State W. Richard

Webb,

MD

H. Dirk

#{149}

Sostman,

experience has been gained with magnetic resonance (MR) imaging of thoracic diseases. Although many different uses of this technique have been proposed, only a limited number have been shown to have a significant clinical role in chest imaging (1-4). It is our intent to review these clinical applications of thoracic MR imaging. ONSIDERABLE

TECHNIQUES Specific imaging protocols will be presented in tabular form in the mdividual discussions of clinical applications. Although the protocols listed are specific for a high-field-strength imager (1.5 T), equivalent techniques can be used with different imagers and lower-field-strength systems. In the thorax, diagnostic images are readily obtained by using field strengths of 0.35-0.5 T. The advantage of use of these field strengths is that motion-related artifacts are less prominent; the disadvantage is a lower intrinsic signal-to-noise ratio. Some techniques are common to all chest imaging protocols. Synchronizing images to the electrocardiogram (ECG) by various methods greatly improves image quality and should be performed in almost all thoracic MR imaging procedures (1,3,5). Dis-

Index

Aorta, MR, 56.1214 #{149} Heart, MR. Lung neoplasms, MR. 60.3 #{149}Mediasneoplasms, 67.3 #{149}Thorax, MR. 60.1214 MR, 93.1214

terms:

51.1214 tinum, Veins,

Radiology

i

From

#{149}

1992;

the

182:621-630

Department

of Radiology,

Univer-

sity of California, San Francisco (W.R.W.), and the Department of Radiology, Box 3808, Duke University Medical Center, Durham, NC 27710 (H.D.S.). Received June 21, 1991; accepted and revision requested August 22; revision received October 1. Address reprint requests to H.D.S.

RSNA, 1992

Art

MD

MR Imaging ofThoracic Clinical Uses’

C

ofthe

Disease:

crete phase-encoding artifacts and blurring due to respiratory motion also degrade thoracic MR image quality. Application of the phase-encoding gradient in an order based on the respiration period can be used to reduce respiratory artifacts without increasing imaging time, although it does not reduce image blurring (6); we use this approach routinely for all thoracic MR imaging. Another approach is to obtain numerous signal averages; this prolongs imaging time and is suitable only for imaging with very short repetition time (TR). Respiratory gating, in which signal acquisition is limited to periods of apnea, has had limited success (7) and is not dinically useful. A significant advantage of MR relative to computed tomography (CT) is direct imaging in sagittal, coronal, and oblique planes; sagittal or coronal MR images can provide anatomic information not available on transaxial

CT or MR images

(8-13).

perform, tolerate,

is easier for sick patients to often provides more ancillary

information, and has an established role in the clinical diagnosis of a number of entities. However, it is a mistake to think of CT and MR as necessarily competitive. Rather, CT and MR are complementary in many instances-each has particular strengths that may be advantageous in specific circumstances.

Structures

that are oriented longitudinally in the sagittal or coronal planes, such as the aorta, can be imaged along their axes. Imaging in the sagittal or coronal plane allows resolution of the edges of structures that lie in or near the transaxial plane, such as lesions in the aorticopulmonary window.

CLINICAL THORACIC

solving tool, in patients who have equivocal or confusing CT findings or in whom specific anatomic information is required that is less clearly demonstrated with CT. In such cases, a limited number of MR images can be helpful. It is important to understand, however, that if MR imaging provides diagnostic information that is merely equivalent to that of CT, then CT is usually the most appropriate clinical study. CT is cheaper, more readily available, usually takes less time to

INDICATIONS MR IMAGING

FOR

In certain situations, MR imaging provides diagnostic information that is superior to that of CT. In these situations, MR should be used as the primary imaging modality (Fig 1). These primary uses of MR generally relate to its ability (a) to image vessels, (b) to distinguish different tissues, (c) to image in nontransaxial planes, or (d) to obviate the administration of iodinated contrast material. In many other instances, however, MR is best reserved as a secondary or problem-

Lung

Cancer

The cancer requires

use of MR imaging for lung evaluation and staging usually a combination of ECG-gated

Ti- and T2-weighted imaging sequences (Table 1), although the sequences used and the planes required will vary with the indication for the study (5,i4-21). Administration of gadopentetate dimeglummne (22) sometimes can be of value but is not required routinely.

In patients can have diagnosis invasion

(12,22-24).

with

lung

cancer,

MR

a primary clinical role in the of chest wall or mediastinal by the primary lung tumor

The

extent

of chest

wall

invasion adjacent to a lung tumor may be better shown by using MR

Abbreviations:

DVT = deep venous thrombosis, ECG = electrocardiogram, GRE = gradientrecalled echo, NSA = number of signals averaged, TE = echo time, TR = repetition time.

621

than CT because of better contrast on Ti- and T2-weighted images between tumor and chest wall fat and muscle (i5,24,25); short-inversion-time inversion-recovery MR sequences, which reduce signal from fat, further enhance the contrast between tumor and chest wall soft tissue (25). These sequences have also been utilized for imaging chest wall involvement in patients with lymphoma (25). MR imaging in the sagittal or coronal planes can be advantageous in evaluating some tumors invading the chest wall, particularly those at the lung apex (10,12,22). In patients with a Pancoast tumor who are being considered for resection, the extent of chest wall invasion and involvement of the subclavian artery or brachial plexus are often better shown with coronal MR than transaxial CT or MR; MR is strongly recommended when superior sulcus invasion is suspected (Fig 2). The anatomic information provided by MR imaging can be of great value in helping the surgeon decide if resection is possible and if so, what approach to use. In the Radiologic Diagnostic Oncology Group study (5), MR was found to be more accurate than CT in the diagnosis of mediastinal invasion, but this result was based on a small nurnber of patients who had invasion. MR is occasionally performed in this setting, particularly when vascular or cardiac invasion is suspected. It has been reported that MR is more accurate than CT in the diagnosis of mediastinal invasion (20) and vascular invasion by lung cancer (22,23). MR is similar to CT in its ability to depict and define mediastinal lymph nodes (Table 2) (5,14,15,17-21,26). Thus, one would expect it to have a similar accuracy in the diagnosis of mediastinal lymph node metastases in patients with lung cancer, if node size is the sole criterion for determining tumor involvement. Indeed, several studies have compared the accuracies of CT and MR and shown them to be similar (Table 2) (5,14,21). Furthermore, the Ti and T2 of mediastinal lymph nodes do not allow the differentiation of benign nodes from those involved by tumor (27,28). The use of gadopentetate dimeglummne for imaging mediastinal nodes and masses also does not allow differentiation of benign from malignant processes (22). In some cases, particularly aorticopulmonary window or subcarinal adenopathy (28), MR is able to demonstrate nodes better than CT because of its ability to image in the coronal or sagittal plane (8,10,1 i,22); however, 622

#{149} Radiology

Cases in Which MR a Primary Modality

Can Be Used

wall invasion by tumor Evaluation of superior sulcus

as

Chest

Mediastinal

invasion

by

tumors

Aortic

dissection

Congenital

venous

Body

Pulse sequence TR/echo time (TE)

ECG-gated spin-echo Option A (better T2 weighting): interval/20

Cases

in Which

a Secondary

obstruction

MR Is Best Used

as

Modality

Diagnosis

Differentiation

of hilar

consolidation

or hilar

(NSA) Presaturation, reordered phase encoding, 7-mm sections with 3-mm gap Sagittal or coronal plane, fat saturation for 12weighted images, gradient-echo (GRE) images for vascular compromise, contrast-

mass

mass

from

or atelectasis

invasion

Matrix, no. of signals averaged Other

of mediastinal

by mediastinal

or

Optional techniques

mass cancer

staging

Detection

of nodules

Congenital

anomalies

in central of the

lung great

enhanced weighted

vessels (children) Cardiac mass Figure tng.

1.

Clinical

uses of thoracic

70

msec Option B (faster): R-R interval/20, 60 msec 256 x 128, 2

thrombosis

plexopathy

(a) R-R msec and

(6) R-R interval/20,

venous

Brachial

hilar

great

Coil

mass

Mediastinal

Lung

of the

or Staging

Setting

(adults)

Paracardiac

Vascular

mass

aneurysm

anomalies

vessels Deep

and

Parameter

tumor

Posterior mediastinal mass Differentiation of fibrosis and

Table 1 MR Technique for Mediastinal Hilar Mass and Lung Cancer

Tiimages

MR imag-

this does not confer an overall advantage in accuracy. The use of coronal or sagittal MR imaging for optimal demonstration of aorticopulmonary or subcarinal adenopathy or mass should be considered a secondary indication for MR. Although MR imaging may be more accurate than CT in depicting the presence or absence of hilar lymph nodes in patients with lung cancer (5,14,29-31), this usually is not of clinical significance. However, it has been suggested by several authors (14,22, 23,32-35) that hilar mass and distal lung consolidation resulting from bronchial obstruction can be distinguished on MR images (Fig 3). This differentiation is sometimes of clinical value, and MR imaging is recommended as a secondary imaging study if CT findings are inconclusive. It has been reported (32,33) that with short TR values (150-500 msec), tumor appears more intense than distal lung disease. However, it is generally found that bronchogenic carcinoma and distal collapse are most easily distinguished with T2 weighting (14,23, 34,36); on T2-weighted images, the lung consolidation appears more intense than the hilar mass (Fig 4). Nonobstructive collapse appears less intense (36). Similar results in distinguishing mass and consolidation can be achieved by using gadolinium-enhanced Ti-weighted imaging; Kono and others (22) distinguished these by

using T2-weighted MR in 77% of patients, while in 80% they could be distinguished after administration of gadopentetate dimeglumine. Mediastinal invasion contiguous with a hilar mass is probably best imaged with MR (23). The use of MR in patients who had lung cancer to evaluate for tumor recurrence after pneumonectomy has been studied in a small number of patients (37). MR imaging was slightly more efficient than CT in identifying the vascular and bronchial stumps, the postpneumonectomy space, and lymph nodes and better depicted cancer recurrence when present (37).

Mediastinal

and

Hilar

Mass

In the diagnosis of mediastinal or hilar mass, transaxial MR imaging usually is performed with both Tiand T2-weighted spin-echo sequences, but the use of either depends on the indications for the MR study (Table 1) (1-3,29,33,38). The Tiweighted images are most helpful in distinguishing mass from fat and in defining vascular anatomy (1-3,30). The T2-weighted images are helpful in showing inhomogeneity within the mass and fluid collections and in distinguishing tumor from fibrosis or chest wall musculature. MR imaging is not often indicated as the primary imaging modality in patients suspected of having mediasMarch

1992

2. Superior sulcus carcinomas. (a) CT and (b) Ti-weighted MR images in a patient with a superior sulcus tumor. On the MR image, the tumor is clearly separated from the subclavian vein (large arrow) and artery (small arrow). There is no evidence of marked invasion, and, thus, this tumor is probably resectable. (c) Ti-weighted, ECG-gated coronal MR image in a different patient with a superior sulcus tumor. The extent of chest wall invasion is well demonstrated. Figure

Table 2 Results of Studies Comparing Metastases in Patients with

CT and MR in Diagnosis Lung Cancer

of Mediastinal

residual masses ation treatment, ual mediasfinal

Node

NO-i vs N23* No. of Patients

Study Martinietal(16) Mussetetal(i5) Pattersonetal(21) Laurent et al (20) Grenieretal(19) Webb et al (14) *

NO-I

=

no mediastinal

34 44 84 120 84 155 node

metastases,

Sensitivity

(%)

Specificity

(%)

Accuracy

(%)

CT

MR

CT

MR

CT

MR

87 91 7i 79 46 52

87 82 71 93 53 48

79 82 89 82 79 69

68 85 91 74 79 64

82 84 82 81

76 84 83 81

65

61

ipsilateral

or contralateral

N2-3

tinal or hilar mass, but a secondary role may sometimes be appropriate. For example, the MR appearances of normal thymus and thymic abnormalities have been well described (39-4i), but in recent studies comparing the accuracies of CT and MR in the diagnosis of thymic lesions, MR has not been found to have a significant advantage (42,43). However, MR often is useful for diagnosing mediastinal or hilar mass in patients who are unable to tolerate iodinated contrast agents (Fig 4). Other primary uses of MR imaging include the diagnosis of mediastinal abnormalities that are suspected to be vascular, the evaluation of posterior mediastinal or paravertebral masses and neurogenic tumors (3,44), and the distinction of mass from fibrous tissue in a patient with treated lymphoma or carcinoma in whom tumor may have recurred (22). MR is useful for imaging posterior mediastinal or paravertebral masses and can be used as the initial examination (44,45). MR allows the accurate assessment of tumor extension into Volume

182

Number

#{149}

3

=

mediastinal

node

metas-

the spinal canal or involvement of the spinal cord. Also, sagittal or coronal images are valuable in showing longitudinal extension of the pathologic process along the spine (44).

In patients

who

have

undergone

lung or mediastinal radiation therapy for treatment of a mediastinal mass, differentiation of radiation-induced fibrosis from recurrent tumor can be difficult with CT. Since biopsy confirmation of recurrent tumor usually is required before additional treatment is begun, localization of areas that are suspicious for recurrent tumor can be important. It has been reported that recurrent carcinoma sometimes can be distinguished from posttreatment radiation fibrosis by using T2weighted (46) or gadolinium-enhanced ation

(22) MR. However, differentiof tumor from associated

inflammatory disease may be difficult (46,47). A recent article (48) showed that MR can play an important role in the follow-up of patients who have been treated for mediastinal Hodgkin disease by helping determine that

weighted in most

are benign. After radithe intensity of residmasses on T2-

images patients

markedly decreased (48); a high-intensity

residual mass, although not specific for persistent or recurrent tumor, might indicate the need for biopsy or close follow-up (49). The MR appearances of untreated mediastinal masses associated with fibrosis have also been

reported

in patients

with

lymphomas

(50) and fibrosing mediastinitis (5i). In most patients with benign mediastinal lesions, values of Ti and T2 do not appear to differ from those of patients with malignant tumors (27,28, 52,53). However, fluid-filled or necrotic masses can be detected on the basis of long Ti and T2 values (53). In patients with fluid-containing lesions, T2-weighted images show a marked increase in signal intensity and can demonstrate mnhomogeneity invisible with short TR and TE values. In some patients, cystic or fluid-filled masses can be diagnosed on MR images when they cannot with CT. Other mediastinal masses appear more inhomogeneous on MR images than on

CT scans,

but

appearances

are usually

nonspecific.

Lung

Nodules

MR is of limited

clinical

value

in the

diagnosis of pulmonary parenchymal disease (1,3,4,44) but may play a clinical role in some cases of suspected lung nodules. MR has been found to be slightly less sensitive than CT in

detection

of small

most locations more sensitive central lung to distinguish

(54). than nodules from

lung

nodules

in

However, MR is CT in detection of that are difficult vessels on the CT Radiology

623

#{149}

V.;. .

l(p

1

5,.

a. Figure

b.

3. Differentiation of hilar mass, consolidation, patient with a right hilar mass and lung consolidation pleural fluid collection (arrows) appears less intensc. lung consolidation and the pleural effusion. (c) On

images. For example, corticotropinproducing bronchial carcinoid tumors in the central lung may be more easily seen by using MR imaging. In one recent study (55), MR and CT were performed in iO patients with surgically proved corticotropin-producing bronchial carcinoid tumors. In eight of the 10, the CT and MR images were equivalent in the detection of bronchial carcinoid tumors. In two patients, CT scans were equivocal but MR images showed tumors in the middle third of the lung. The use of MR as a secondary modality in this setting would seem to be appropriate.

Acquired

Aortic

Disease

Aortic dissection-Imaging studies in patients with possible aortic dissection must document the presence of dissection and establish which segments of the aorta are involved. Both sensitivity and specificity must be high, since false-positive and falsenegative errors are associated with serious consequences. Determination of the type of dissection must also be accurate, because type A dissections usually require immediate surgery whereas type B dissections normally are managed medically. Special problems that may influence management include establishing the site of the proximal intimal tear; dissection without intimal rupture (56); penetrating atherosclerotic ulcer (57,58); and pseudoaneurysm, progression and other complications of medical and surgical management (59,60). Aortic dissection can be imaged with aortography, CT, ultrasound (US), and MR. Although transthoracic US can be used to assess the ascending aorta, its limited field of view gen624

#{149} Radiology

c. and pleural effusion. (a) The Ti-weighted, ECG-gated MR image (TE = 30 msec) in a does not allow clear differentiation of hilar mass and consolidation; however, a small (b) With T2 weighting, the hilar tumor (arrows) appears less intense than the peripheral the CT scan, the differentiation of mass, consolidation, and effusion cannot he made.

erally makes it less useful (61). There is promising experience with transesophageal US, but this technique is not noninvasive (6i,62), since it necessitates sedation and is associated with the risk of esophageal injury. Aortography is still the standard method for demonstrating aortic dissection, but it is invasive and has a low prevalence of false-positive diagnoses and a higher prevalence of false-negative diagnoses (63). CT is accurate and commonly used for evaluating aortic dissection (64). At CT, the intimal flap and the true and false lumina can be identified accurately (65). The demonstration of displaced intimal calcification is a useful ancillary capability that is relatively unique to CT (64). Problems of CT include the need to perform dynamic scanning at correct anatomic levels with a compact bolus of contrast material (66) and the limited ability to assess aortic valve function and branch vessel involvement (information that some surgeons require). MR imaging offers several advantages in studying aortic dissections.

No contrast

material

is required,

L!’-_____ Figure

4.

Ti-weighted

MR

image

in a pa-

tient with a thymoma. A lobulated mass is visible in the anterior portion of the mediastinum, which is characteristic of this tumor. This patient previously experienced a reac-

tion clinical

to contrast evidence

material

and

of superior

demonstrated vena

cava

syn-

drome. The sagittal MR image demonstrates the tumor well and shows abrupt terminahon sion and

of the superior was confirmed at MR venography.

vena on

the

cava. Tumor invaaxial MR image

and

direct multiplanar images are sometimes advantageous. Cine MR technique can allow assessment of the presence and degree of aortic insufficiency (67) and the function of the left ventricle (68). It has been our experience that cine MR sometimes can depict sites of intimal perforation. Mediastinal hematoma, hemothorax, and hemopericardium can be detected. However, MR also has limitations in assessing dissections: Calcification is inconspicuous on MR images, some patients are excluded from MR imaging for safety reasons, MR examinations for dissection usually take

longer to perform than do CT studies, and artifacts are more often a problem with MR than with CT (69). Experience is required to recognize flow artifacts and differentiate slow flow from thrombus (70), although cine MR usually enables confident diagnosis in cases of prominent flow artifacts on the spin-echo images, and phasecontrast images can assist in detecting slow flow (71). Our experience suggests that MR is less accurate than aortography but more accurate than CT in the determination of branch vessel involvement. March

1992

tie experience

with

Although

MR

MR might

than and

CT, the sustaining

tized

patient

in this

setting.

be more

accurate

problems of monitoring the massively trauma-

make

MR impractical

in

such circumstances. Chronic pseudoaneurysms in survivors of traumatic or iatrogenic

uated

aortic

injury

appropriately

can

with

be eval-

MR or CT

(59,60,86).

Congenital Thoracic In the

5.

Figure

Images of a patient with subsequently underwent phase) shows displaced

who (equilibrium

gram

without

an enhancing

within

the

wall

false

of the

Table 3 MR Technique Dissection

clinically CT and intimal

lumen.

(b) Ti-weighted

which

is consistent

aorta,

for Suspected

Parameter

Aortic

Setting

Coil

Body

Pulse sequence

ECG-gated spin-echo, GRE (eg, cine) R-R intervall2O, 40 (spinecho), 25112, 30#{176} (cine) 256x128,2 Spin-echo: presaturation, reordered phase encoding, 7-mm sec-

TR/TE,

flip angle

Matrix,NSA

Other

suspected MR imaging. calcification

tions

with

3-mm

gap

Cine: flow compensation,

reordered phase 10-mm secwith no gap

encoding, tions

Optional

Oblique

techniques

planes,

sensitive

phase-

images

The relative accuracy of aortography, CT, and MR in depicting and characterizing dissections has not, to our knowledge, been established conclusively. Extensive data indicate that CT is accurate in evaluation of dissection (64). More limited studies also suggest that MR is accurate (70-77) compared with aortography or surgery and that it may be slightly more sensitive than CT (77). Our experience is that CT and MR have equivalent accuracy for detection of dissection and that both are somewhat more sensitive than aortography (Fig 5). However, no single technique always fulfills all of the requirements for characterization of dissections. A true emergency case is usually best managed initially with aortography; if Volume

182

#{149} Number

3

aortic dissection but a negative aorto(a) Contrast-enhanced CT scan and thickening of the aortic wall

MR image with

subacute

shows

high

signal

intensity

hematoma.

the aortogram is apparently negative in a highly suspect patient, CT or MR imaging should then be performed. CT is best used for less emergent cases in which the patient is clinically less stable. MR is recommended for stable patients or those with contraindications to contrast material administration. MR imaging may also be useful in following up patients with chronic dissection, to detect complications and monitor the results of surgical and medical treatment (60,65,78,79). Our MR imaging technique for suspected dissection is shown in Table Aortic aneurysm and aortic rupture.-

Both

CT (65,80)

and

3.

MR (75,81,82)

have advantages over aortography in the evaluation of thoracic aneurysms. Both are noninvasive means of documenting that a mediastinal mass is an aneurysm, and both can enable assessment of the thickness of the aortic wall, accurate measurement of the size of the aorta, and characterization of the longitudinal extent of the aneurysm. Excellent delineation of calcification is a minor advantage of CT, whereas MR imaging does not necessitate contrast material administration and can be used to detect and grade the severity of aortic insufficiency. The detection of aortic insufficiency is particularly useful in assessing aneurysms of the sinuses of Valsalva, a task for which CT is ill suited (83). Aortic rupture secondary to trauma probably is best evaluated with aortography; the false-negative rate of CT may be unacceptably high (83,84), although some researchers have reported better results (85). There is lit-

Anomalies Great Vessels pediatric

of the

population,

US and

angiography remain the standard methods for demonstrating great yessel anomalies with associated cardiac malformations and physiologic sequelae. However, while the technical problems of MR are greater in children than in adults, diagnostic MR images can be obtained on small infants with careful technique, and sedation is often needed for US in patients who must be sedated before they undergo MR imaging. Accordingly, MR can be used (usually as a secondary procedure) for delineating congenital vascular and cardiac lesions in infants and children. In adults with congenital anomalies of the great vessels, MR is often the procedure of choice because of its large

field US)

of view and

(compared

its ability

with

to acquire

that

of

images

in

multiple planes without limitation due to the volume of contrast material administered (compared with that needed for angiography). Published experience with MR imaging in developmental anomalies of the great vessels has focused on study of aortic coarctation and pulmonary artery obstruction, and evaluation of the results of correction of these lesions. Coarctation (75,87-96) is accurately delineated by MR. Complications of treatment, including restenosis and aneurysm, can be detected (87,94,96). Clinical acceptance of MR as the sole diagnostic procedure depends on a willingness to forgo direct measurement of the pressure gradient across the lesion. MR is the noninvasive imaging procedure of choice for detecting central pulmonary artery obstruction (97-101), evaluating the potential for palliative shunts (97),

and

assessing

the

results

of surgery

(i02) (Fig 6). Standard MR techniques, however, are not accurate for assessing peripheral pulmonary vascular obstruction (99). Comparisons of MR with transthoracic US have in general shown MR to be superior for demonstration of great vessel anomalies (90,93). Radiology

#{149} 625

The diagnosis with MR of a variety of other congenital vascular anomalies has been reported (90,i03-iiO). These reports all describe accurate depiction of the vascular anatomy. Systemic blood flow to pulmonary blood flow ratios have been measured with phase-contrast MR (iiO). The vascular supply of sequestrations can be identified with MR, thus permitting more confident noninvasive diagnosis (iii). In our practice, pulmonary artery obstruction and suspected vascular ring have been the most frequent clinical indications for MR imaging in the setting of developmental vascular anomaly. We use a combination of spin-echo and cine MR imaging to evaluate such cases, with technique similar to that shown in Table 3 (except that section thickness and onentation patient

Cardiac Lesions

are tailored to the individual size and vascular anatomy).

and

Paracardiac

Mass

Primary and metastatic cardiac tumors are uncommon and usually are detected initially with US. MR also is accurate in delineating the presence and extent of such lesions (ii2-i26). MR is used appropriately as a problem-solving technique in patients with inconclusive US findings and is of particular value in identifying false-positive US results (i26). MR has been shown to demonstrate the presence of fat within cardiac lesions with relatively good specificity (ii2,ii3, 121), which should be further improved by newer techniques such as frequency-selective saturation pulses (i27) and multipoint phase-difference imaging (i28). The more common challenge for MR in diagnostic specificity is to distinguish between intracardiac tumor and thrombus. This problem has not been addressed conclusively in the literature; our own experience suggests that tumor and thrombus often can be distinguished. An important exception is that atrial myxomas and atnial thrombi have variable and overlapping appearances and cannot be distinguished reliably with MR. Intravenously administered gadopentetate dimeglumine may sometimes be useful to distinguish thrombi from tumors. MR imaging is most valuable as an initial investigation in patients suspected of having combined vascular and extravascular involvement, since it can demonstrate both

vascular

and

soft-tissue

cesses with equal accuracy evaluate such patients, we use cardiac-gated spin-echo 626

#{149} Radiology

pro-

(Fig 4). To primarily imaging

with techniques shown in Table

similar 3; cine

used selectively mised flow and dial effusion.

to assess questionable

Venous Obstruction Thromboembolism We

perform

venous

to those MR imaging

is

compropericar-

and

MR

imaging

to

evaluate suspected deep venous thrombosis (DVT) in the pelvis and lower limbs or to evaluate mediastinal venous obstruction (either extrinsic due to tumor or fibrosis, or intrinsic due to thrombosis). MR does not require venous access or contrast matenial and allows study of the entire yenous system. DVT.-Although the diagnosis of DVT is not strictly in the realm of thoracic imaging, it is important in patients suspected of having pulmonary embolism. The possibility of DVT may be evaluated with MR (a) as either a primary test or as a problem-solving measure after inconclusive results are obtained with another test; (b) in a patient with documented pulmonary embolism who is at high risk for persistent or recurrent DVT; or (c) as an alternative to pulmonary artenography in a patient with an abnormal lung scan (the role of venous imaging per se for this indication is evolving) (i29,i30). MR imaging is not currently acceptable for routine imaging of pulmonary emboli. Venous thrombi can be seen with spin-echo technique (131-134), and high accuracy has been reported (135). We prefer to use fast GRE technique (Table 4), which-in our experience of over 250 cases (136,137) (Spnitzer CE, Sostman HD, unpublished data) and that of others (138i40)-appears to be highly accurate. Our limited comparative experience suggests that GRE technique has greater specificity than spin-echo imaging for DVT (iOO% for GRE imaging vs 75.0% for spin-echo in i8 proved cases [Spritzer CE, Sostman HD, unpublished data]), but to our knowledge a definitive comparison has not been published (i40,i4i). With GRE technique, acute DVT is diagnosed when a filling defect is seen within a vein (Fig 7) or when a low-intensity occlusion of an enlarged vein is present (137). When an irregulan or occluded but small vein is present in association with collateral veins, we diagnose chronic DVT (Fig 7); however, the reliability of the latten MR diagnosis has not been proved conclusively. Experience is needed to distinguish between DVT and low

.* I-

:.‘

Figure

6.

infant

ECG-gated

who

had

MR

undergone

image

of a 3.5-kg

a bilateral

central

shunt procedure. The shunts (arrows) are seen, and flow void indicates patency. Flow within the shunts was confirmed at cine MR imaging.

Table

4

MR Technique

for Suspected

Parameter Coil

DVT

Setting Body for pelvis, thighs, abdomen, thorax, shoulder; head for calves; surface cial purposes

Pulse

TRITE,

Matrix,

sequence

flip angle

NSA

for spe(rarely

used) GRE (eg, gradient-recalled acquisition the steady state) 33112,

in

60#{176}, standard

method; 100112, 60#{176}, slow flow (eg, calves) 256 x 128, 2 (standard method), 256 x 256, 1 (calves)

Other

Flow compensation,

Optional

5-mm sections with 5-mm gap Spin-echo images for

techniques

high-signal-intensity clot, flow defect; phase-contrast images (for slow flow); uration (superior

presatonly)

intravascular signal that is caused by dephasing or slow flow. High-intensity thrombus (i42,i43), which is not uncommon in the cerebral vasculatune, is rare in the lower-extremity veins. The alternatives to MR for imaging DVT are standard venography (130, i44-i46) and US (i47-i49), which are well-characterized tests with established advantages and limitations. We currently recommend (150) that US be the first imaging procedure employed in patients with suspected DVT, provided that calf DVT would not be treated and that there is little suspicion of pelvic DVT, since US may be less accurate in these regions. If US March

1992

94%

and

a specificity

of 100%,

negligible

interobserver

This ages

emphasized sufficient

report were

with

167).

variability. for

that axial identification

im-

of jugular and vena caval occlusions, but that accurate evaluation of pathologic conditions of brachiocephalic, subclavian, and axillary qumred sagittal imaging.

cent

study,

clavian Figure 7. MR image with GRE technique of a patient with acute left common iliac and presumed chronic right common iliac DVT. A distended left iliac vein (V) is seen with lowintensity intraluminal filling defect. On the right, the iliac vein is absent but the artery (A) and prominent collateral veins are seen.

TableS MR Technique

Peripheral

Plexopathy

Parameter Coil

Body

Pulse sequences

needed) Ti- and 12-weighted spin

TRITE,

flip angle

Matrix,

NSA

Presaturation;

Optional techniques

coil

Brachial

500120; 2,000120,

respira-

compensation;

axial, sagittal, coronal Ti-weighted (5-mm section with i-mm gap); usually sagittal 12-weighted (7-mm section with 3-mm gap) Contrast-enhanced Tiweighted images; GRE vascular images (see Table 4)

results are indeterminate, if calf or pelvic DVTs are clinical issues, or if symptoms persist, venography or MR then can be considered; the final decision should be based on cost, availability, patient comfort, and local expertise.

venous

obstruction-We

consider MR the noninvasive procedune of choice for cross-sectional imaging of mediastinal venous disease. The MR diagnosis of mediastinal yenous compromise by tumor, fibrosis, inflammatory mass, and thrombus has been the subject of several reports (9,i4,29,53,i5i-i53). To our knowledge, no study has prospectively investigated MR in this setting, and comparisons primarily have been with CT. One recent study (153) reported Volume

MR 182

to have #{149} Number

same

as those

for

Plexopathy

Imaging is useful in patients suspected of having metastatic disease, radiation injury, primary tumor, or traumatic injury involving the brachial plexus. Clinical evaluation usually can indicate the causes of concern

and

whether

a sensitivity 3

of

the plexopathy

is likely

to arise from a central or peripheral lesion (i56), but it cannot demonstrate definitely the cause and site of in-

volvement. radiation

Metastatic disease injury are the most

and common

causes of brachial plexopathy, and the distinction between these is difficult, although pain, Homer syndrome, and

trunk

involvement

are charac-

teristic of metastatic involvement (157,i58). Accordingly, imaging has achieved a major role in the evaluation of patients with brachial plexopathy. CT has been accepted generally as the most useful imaging procedure

in patients

suspected

of having

Limited

mors

CT

fibrosis have

(159,160).

been

Both

(156).

Primary

demonstrated

tuand

myelography (156,i6i,i62) have been used in traumatic lesions of the plexus; some authors recommend myelography as the initial procedure (i56), whereas others (16i,163) stress its limitations. Published experience with MR imaging of the brachial plexus is more limited

than

that

with

CT

(i6i,i64-

CT (i56).

The

published

and

data

have

sug-

fibrosis of cancer

plexopathy is accurate

may

plexus

have indicated (i2,i6i,i65,i67)

be superior

documenting

from tumor patients with

to CT (i2,i6i)

or excluding

involvement

Despite

the

in

brachial

by tumor.

somewhat

lished data on MR. CT and myelography

limited

pub-

it has supplanted for imaging

the

brachial plexus in our practice. cally central lesions fall in the

Clinirealm

neuroradiologic

and

investigation

of

should be evaluated with a posterior neck coil and cervical spine imaging technique. Clinically peripheral lesions (Table 5) should be evaluated initially with the body coil; this should be supplemented, if necessary, by surface coil images. The anatomy is first mapped with Ti-weighted images in at least two planes, and the study is completed with selective use

of other

pulse

sequences

pniate anatomic plane(s) lesions and associated pathologic abnormalities.

in MR evaluation thy

include

of brachial

limited

appropriate

in the approto delineate (eg, vascular) Limitations

use

plexopa-

experience

with

of gadolinium

(Fig 8);

limited data concerning differentiation between tumor, fibrosis, and diation injury, specifically in this

gion;

and

subgross

limited trauma

neuritis.

Many

apply

as well

experience (i6i)

with

and

of these

rare-

idiopathic

limitations

to CT.

meta-

with

CT (156,i59)

superior

that MR is superior to other techniques for evaluating plexus trauma (i6i,i62) and

brachial that MR

static disease (i56,159), but it may be less useful in documenting the absence of metastases in patients with

radiation

provides

of MR over

differentiating (16i). Studies

perform vascular imaging for this indication with GRE technique as for DVT, but additional spin-echo images are obtained routinely if there is a suspicion of an extravascular process. Our diagnostic criteria for intravascu-

are the

MR

superior soft-tissue contrast afforded by MR is advantageous for detection of pathologic conditions (i6i,i65,i67). gested imaging brachial

That study reported 100% specificity but only 25% sensitivity for partially occluding thrombi and 80% sensitivity for complete occlusion (i54). We

lower

Mediastinal

spin-

this results.

if

80 256 x 128,2 tory

to sub-

coronal

echo

Ti-weighted, 12-weighted

Other

limited

only

DVT, while soft-tissue lesions are evaluated with reported criteria for tumor and fibrosis (46,i55).

Setting (surface

was

used

vantages

veins also reAnother re-

echo images. In our experience, approach leads to inaccurate

lar thrombus

for Suspected

Brachial

which

veins,

However,

delineation of the normal anatomy of this region (i64,i66), due mostly to its multiplanar capabilities. Lack of streak artifact from bone and accurate identification of vasculature are ad-

FUTURE

DIRECTIONS

THORACIC

MR

IN

IMAGING

Rapid technical developments tinue in MR imaging, including

that are applicable directly evaluation. Although many

conmany

to thoracic clinically

relevant developments will occur in the near future, we anticipate major advances in three areas: lung parenchymal imaging, pulmonary vascular

imaging,

and

cardiac

imaging.

imaging

of the

lung

parenchyma

until

now

susceptibility

been

hindered artifacts,

MR has

by magnetic motion Radiology

arti#{149} 627

facts, and poor signal-to-noise The advent of shorter-TE quences, better understanding

pulse

ratios. seof sus-

ceptibility variations, and faster imaging techniques should lead to new clinical applications in characterizing focal and diffuse pulmonary parenchymal disease. Pulmonary vascular

MR imaging

has been

limited

by fac-

tors similar to those that have frustrated attempts at parenchymal imaging, as well as by the complex anatomy and physiology of the pulmonary circulation. We development of clinical niques for the detection embolism

and

ment of lung MR provides

the

anticipate the MR techof pulmonary

noninvasive

assess-

blood flow. Although excellent anatomic and

functional images of the heart, it has not provided enough unique information to achieve a major role in routine cardiac evaluation. The advent of fast imaging techniques, tagging methods, and greater understanding of contrast agents for the myocardium will, we believe, lead to the emergence of MR as the premier cardiac imaging modality. a

b.

a.

Figure istration mass

2.

3.

4. 5.

6.

7.

8.

9.

10.

1 1.

12.

628

Gamsu imaging

C, Sostman D. Magnetic resonance of the thorax. Am Rev Respir Dis 1989; 139:254-274. Webb WR. The role of magnetic resonance imaging in the assessment of patients with lung cancer: a comparison with computed tomography. J Thorac Imaging 1989; 4:65-75. Gefter W. Chest applications of magnetic resonance imaging: an update. Radiol Clin North Am 1988; 26:573-588. Fkhcr MR. Magnetic resonance for evaluation of the thorax. Chest 1989; 95:166-173. Webb WR, Gatsonis C, Zerhouni EA, et aI. CT and MR imaging in staging non-small cell bronchogenic carcinoma: report of the’ Radiologic Diagnostic Oncology Group. Radiology 1991; 178:705-713. Bailes DR, Gilderdale DJ, Bydder Respiratory ordered phase-encoding a method for reducing respiratory artifacts in MR imaging. J Comput

et a!. (ROPE): motion Assist To-

obtained

brachial

also

with

plexus,

that, GRE

while

which

the

technique

contrast-enhanced

reveals

chogenic carcinoma: staging with MR compared with staging with CT and surgery. Radiology 1985; 156:117-124. Musset D, Crenier P, Carette MF, et al. Primary lung cancer staging: prospective comparative study of MR imaging with CT. Radiology 1986; 160:607-611. Martini N, Heelan R, Westcott J, et al. Comparative merits of conventional, computed tomographic, and magnetic resonance imaging in assessing mediastinal involvement in surgically confirmed lung cancer. I Thorac Cardiovasc Surg 1985; 90:639-648.

MJ, Henkelman

20.

22.

23.

24.

Chest-wall invasion by carcinoma lung: detection by MR imaging. 148:1075-1078.

of the AJR 1987;

and after unenhanced

25.

26.

27.

28.

structure

(arrow), occlusion

enhancement

due

the

vein

by

the

of

the

nodes: a comparative 279-282. Clazer CM, Orringer

AIR 1988;

MB, Chenevert

ease. Webb

in sarcoidosis 1986;

Eur J Radio! WR, Camsu

and

C, Stark

resonance

Moore EH. of the normal

hila.

Clazer

CM, Cross

BH, Aisen

Francis

IR, Orringer

MB.

pulmonary

hilum:

AM.

a prospective with

Magnetic

E, Evens RC. bronchogenic

postobstructive resonance

puted

lung

LE,

of the

comparative

cancer.

resonance

AiR

1985;

imaging

of

lobar imaging:

tomography.

Differentiation of carcinoma from collapse comparison

Invest

by magnetic with com-

Radiol

1987; 22:

538-543. Shioya S, Haida M, Ono Y, Fukuzaki M, Yamabayashi H. Lung cancer: differentiation of

tumor,

necrosis,

and

atelectasis

TI and T2 values measured ogy 1988; 167:105-109.

38.

AM, Quint Imaging

the thorax. Radio! C!in North Am 1984; 22: 829-846. Levitt RC, Glazer I-IS, Roper CL, Lee JK, Murphy WA. Magnetic resonance imaging of mediastinal and hi!ar masses: comparison with CT. AIR 1985; 145:9-14. Tobler J, Levitt RC, Clazer HS, Moran J,

Crouch proximal

37.

Radiology

Magnetic resonance imaging of mediastinum. Cardiovasc Inter1986; 8:306-313.

study in patients 145:245-248.

Cohen

dis-

DD,

31.

36.

TL, et a!.

Castleman’s

imaging

Webb WR. the hila and vent Radiol

35.

151:

6:145-148.

30.

34.

tumor. tumor.

study.

and abnormal pulmonary 1984; 152:89-94.

33.

tu-

visi-

Mediastina! lymph nodes: relaxation time/ pathologic correlation and implications in staging of lung cancer with MR imaging. Radiology 1988; 168:429-431. de Ceer C, Webb WR, Sollitto R, Colden J. MR characteristics of benign lymph node en-

Magnetic

32.

to

is not

Bergin CJ, Healy MV, Zincone CE, Castellino RA. MR evaluation of chest wall involvement in malignant lymphoma. J Comput Assist Tomogr 1990; 14:928-932. Platt JF, Glazer CM, Orringer MB, et al. Radiologic evaluation of the subcarinal lymph

largement 29.

intravenous adniinimage shows a

as a discrete

is seen venous

RM, et a!.

Crenier P. Dubray B, Carette MF, Frija C, Musset D, Chastang C. Preoperative thoracic staging of lung cancer: CT and MR evaluation. Diagn Intervent Radiol 1989; 1:23-28. Laurent F, Drouillard J, Dorcier F, et al. Bronchogenic carcinoma staging: CT vs MR imaging-assessment with surgery. Eur I Cardiothorac Surg 1988; 2:31-36. Patterson CA, Cinsberg RJ, Poon PY, et al. A prospective evaluation of magnetic resonance imaging, computed tomography, and mcdiastinoscopy in the preoperative assessment of mediastinal node status in bronchogenic carcinoma. J Thorac Cardiovasc Surg 1987; 94: 679-684. Kono M, Sako M, Adachi 5, et al. MR imaging in the assessment of lung cancer patients: primary lung cancer staging, evaluation of therapeutic effect and diagnosis of recurrent tumor. Nippon !gaku Hoshasen Cakkai Zasshi 1989; 49:831-840. Iiapanesel Kameda K, Adachi S. Kono M. Detection of T-factor in lung cancer using magnetic resonance imaging and computed tomography. Thorac Imaging 1988; 3:73-80. Haggar AM, Pearlberg JL, Froelich JW, et al.

seen

marked

137:1456-1462. 19.

before

artery

demonstrated

image

O’Donovan PB, Ross JS, Sivak ED, et al. Magnetic resonance imaging of the thorax: the advantages of coronal and sagittal planes. AIR 1984; 143:1183-1188. Webb WR, Jensen BC, Sollitto R, et al. Bron-

PY, Bronskill

is not

axillary

18.

tion sagittal imaging of in progress. Webb WR, Moore EH. imaging of Radiology Webb WR,

#{149} Radiology

of the

Note

plexus

(a) The Ti-weighted

dimeglumine.

Mediastinal lymph node metastases from bronchogenic carcinoma: detection with MR imaging and CT. Radiology 1987; 162:651656. Batra P, Brown K, Collins JD, Ovenfors CO. Steckel RJ. Evaluation of intrathoracic cxtent of lung cancer by plain chest radiography, computed tomography, and magnetic resonance imaging. Am Rev Respir Dis 1988;

2!.

Moore EH. Sagittal MR imaging of the chest: normal and abnormal. I Comput Assist Tomogr 1985; 9:471-479. Heelan RT, Demas BE, Carave!li JF, et a!. Superior sulcus tumors: CT and MR imaging. Radiology 1989; 170:637-641.

region

to the brachial

Poon

!60:803-810. Batra P, Brown K, Steckel RJ, Collins JD, Ovenlors CO. Aberle D. MR imaging of the thorax: a comparison of axial, coronal, and sagittal imaging planes. J Comput Assist Tomogr 1988; 12:75-81. Webb WR, Gamsu C, Crooks LE. Multisecand coronal magnetic resonance the mediastinum and hila: work Radiology 1984; 150:475-478. Jensen BC, Gamsu C, Sollitto R, Coronal magnetic resonance the chest: normal and abnormal. 1984; 153:729-735. Jensen BC, Camsu C, Sollitto R,

metastasis

17.

GM,

mogr 1985; 9:835-838. Lewis CE, Prato FS, Drost DJ, Nicholson RL. Comparison of respiratory triggering and gating techniques for the removal of respiratory artifacts in MR imaging. Radiology 1986;

Images

14.

16.

the

Ti-weighted

13.

15.

cancer

involvement.

ble.

(b)

Breast

of gadopentetate in

mor

References 1.

8.

Herold monary

CJ, Kuh!man atelectasis:

by means of in vitro. Radiol-

JE, Zerhouni signal patterns

EA. with

Pu!MR

imaging. Radiology 1991; 178:715-720. Laissy IP, Rebibo C, Trotot PM, Iba Zizen Cabanis EA, Benozio M. Post-pneumonectomy evaluation of the chest: a prospective comparative study of MRI with CT. Magn Reson Webb

Moore

MT,

Imaging 1989; 7:55-60. WR, Camsu C, Stark DD, Moon KU, EH. Evaluation of magnetic reso-

March

1992

nance

sequences in imaging mediastinal hiAJR 1984; 143:723-727. Siegel MJ, Glazer HS, Wienerjl, Molina PL. Normal and abnormal thymus in childhood: MR imaging. Radiology 1989; 172:367-371.

63.

mors.

39.

40.

41.

42.

de Geer thymus:

C, Webb assessment

AIR

Emskotter Magnetic gravis: erized

1987;

Normal CT. Radiol-

Burk

65.

66.

Mediasticorrelation surgical

thoracic mography.

H, Lachenmayer L. imaging in myasthenia to mediastinal comput-

tomography?

Dtsch

Med

DJ, Brunberg

JA, Kanal

surface

coil

MR

diology

1987; 162:797-801.

imaging

RE,

Lee

JKT,

Glazer

imaging 48.

HS.

1990; 177:21-22. Nyman RS, Rehn

SM,

1989;

BLG,

72.

et aL

in Hodgkin MR imaging.

disRa-

170:435-440.

73.

49.

Webb WR. MR imaging of treated mediastinal Hodgkin disease (editorial). Radiology 1989; 170:315-316.

50.

Negendank WG, Al-Katib AM, Karanes Smith MR. Uymphomas: MR imaging trast characteristics with clinical-pathologic correlations. Radiology 1990; 177:209-216.

Rholl KS, Levitt

51.

71.

RG, Glazer

HS.

74.

C, con75.

Magnetic

resonance

imaging of fibrosing mediastinitis. 145:255-259. Ross JS, O’Donovan PB, Novoa R, et al. Magnetic resonance of the chest: initial experience with imaging and in vivo TI and T2

76.

AJR 1985;

52.

calculations. 53.

Radiology

1984;

Gamsu

G, Stark

DD,

Webb

Sheldon

FE.

Magnetic

benign mediastinal 151:709-713.

54.

resonance

masses.

of

1984;

78.

NL, Gamsu C, Webb WR. Pulmonary nodules: detection using magnetic resonance and computed tomography. Radiology 1985; 155:687-690. Doppman

JL, Pass

tection noid

HI, Nieman

UK, et al.

of ACTH-producing tumors:

MR

bronchial

imaging

vs CT.

AJR

Yamada

79.

De-

carci-

80.

1991;

81.

347-352. Welch

TJ, Stanson

CM, McKusick of penetrating RadioGraphics 58.

59.

Sheedy

PE II, Johnson

Radiologic atherosclerotic

evaluation ulcer.

1990; 10:675-685. Yucel EK, Steinberg FL, Egglin TK, Geller SC, Waltman AC, Athanasoulis CA. Penetrating atherosclerotic ulcers: diagnosis with MR imaging. Radiology 1990; 177:779-781. Taylor DO, Rehr RB, Thompson JA, Vetrovec

C, Tatum ring after 1990;

60.

AW,

MA. aortic

JU. Aortic pseudoaneurysm occurcardiac transplantation. Am Heart J

61.

by magnetic

Volume

resonance

1990; 97:106-110. Petasnick JP. Radiologic dissection.

62.

82.

83.

84.

120:1222-1225.

Pucillo AU, Schechter AG, Moggio RA, Kay RH, Tenner MS. Herman M. Postoperative evaluation of ascending aortic prosthetic conduits

Shively ography

182

Radiology

evaluation

1991;

BK. Transesophageal in the assessment

#{149} Number

imaging.

3

of aortic

1985; Risius

MJ.

85.

86.

180:297-305. 87.

.

Higgins

1987;

CB.

MR imaging. MD.

CB.

Coarcta-

Radiology MRI

of the great

1986; 146:941-948. Kersting-Sommerhoff

of congen-

arteries.

BA, Sechtem

MR imaging

of the

aortic

AJR UP,

Fisher

of congenital

arch.

AIR

1987;

CB, White

The

thoracic

aorta

1985;

FJ,

Neuhold

95.

%.

97.

1989; 98.

99.

et at.

aorta. 100. R, Higgins

of complications Assist Tomogr

of aortic 1987; 11:

Extracardiac

101.

enhanced

computed

102.

tomography.

Am J Cardiol 1986; 57:282-285. Valk PE, HaleJD, Kaufman L, Crooks LE, Higgins CB. MR imaging of the aorta with three-dimensional vessel reconstruction: validation by angiography. Radiology 1985; 157:

103.

104.

vasculature

surgery:

in candidates

MR imaging.

Radiology

173:503-506.

Gomes AS, LoisJF, Williams RG. Pulmonary arteries: MR imaging in patients with congenital obstruction of the right ventricular outflow tract. Radiology 1990; 174:51-57. Canter CE, Gutierrez FR, Mirowitz SA, Martin T, Hartmann AF. Evaluation of pulmonary arterial morphology in cyanotic congenital heart disease by magnetic resonance imaging. Am Heart J 1989; 118:347-354. Mirowitz SA, Gutierrez FR, Canter CE, Vanflier MW. Tetralogy of Fallot: MR findings. Radiology 1989; 171 :207-212. Sampson C, Martinez J, Rees 5, Somerville J, Underwood

Pernes JM, Grenier P, Desbleds Ml, BruxJL. MR evaluation of chronic aortic dissection. Comput Assist Tomogr 1987; 11:975-981. White RD, Lipton MJ, Higgins CB. Noninvasive evaluation of thoracic aortic disease by

of the 1987; 165:

R, Hallberg M, Sunnegardh J, Thuren A. Magnetic resonance imaging and angiography in the assessment of coarctation of the aorta. Acta Radiol 1989; 30:481485. Sonnabend 5, Colletti PM, Pentecost MJ. Demonstration of aortic lesions via cine magnetic resonance imaging. Magn Reson Imaging 1990; 8:613-618. Rees S, Somerville J, Ward C, et al. Coarctation of the aorta: MR imaging in late postoperative assessment. Radiology 1989; 173:499502. Julsrud PR, Ehman RL, Hagler DJ, Ilstrup for Fontan

by

P. Stoney

abnormalities Radiology

Nyman

DM.

157:149-155.

A, Fezou!idisJ,

Congenital MR imaging.

I, Henze

MJ, HilIJA, Mancuso

W, Olofsson

MR imaging I Comput

94.

et al.

studied

Amparo EG, Higgins CB, Shafton EP. Demonstration of coarctation of the aorta by magnetic resonance imaging. AJR 1984; 143:11921194. Gomes AS, LoisJF, George B, Alpan G, Wilhams RG. aortic arch: 691-695.

Aortic disof MR im-

155:399-406. B, O’DonnellJA,

MR imaging. Radiology Akins EW, Carmichael

R, Longmore

D.

Evaluation

of

Fontan’s operation by magnetic resonance imaging. Am J Cardiol 1990; 65:819-821. Kersting-Sommerhoff BA, Seelos KC, Hardy C, Kondo C, Higgins 55, Higgins CB. Evaluation of surgical procedures for cyanotic congenital heart disease by using MR imaging. AIR 1990; 155:259-266. Coscina WF, Kressel HY, Gefter W, Axel L. MR imaging of double aortic arch. J Comput Assist Tomogr 1986; 10:673-675. Didier D, Higgins CB, Fisher MR, Osaki L,

721-725.

Silverman

Schuierer G, Kaiser W, Zeitler E, et al. Magnetic resonance imaging of aortic aneurysm. Ann Radiol 1985; 28:109-111. GodwinJD, Korobkin M. Acute disease of the aorta: diagnosis by computed tomography and ultrasonography. Radiol Clin North Am 1983; 21:551-574. Egan TJ, Neiman IlL, Herman RJ, Malave SR, Sanders JH. Computed tomography in the diagnosis of aortic aneurysm dissection or

heart disease: gated MR imaging in 72 patients. Radiology 1986; 158:227-235. Ross RD, Bisset GS, Meyer RA, Hannon DW, Bone RE. Magnetic resonance imaging for diagnosis of pulmonary vein stenosis after anomalous pulmonary venous connection. AmJ Cardiol 1987; 60:1199-1201. Guit CL, Bluemm R, Rohmer J, et at. Levotransposition of the aorta: identification of segmental cardiac anatomy using MR imaging. Radiology 1986; 161:673-679. Lynch DA, Higgins CB. MR imaging of unilateral pulmonary artery anomalies. J Comput Assist Tomogr 1990; 14:187-191.

traumatic

Chest

echocardiof aortic pathol-

BA, Higgins

CP, Lipton

WA.

Aufferman

MR.

BD, Jacobstein

abnormalities

Radiology

Thoracic aortic dissections: magnetic resonance imaging. Radiology 1985; 155:407-412. Dinsmore RE, Wedeen VJ, Miller SW, et al. MRI of dissection of the aorta: recognition of the intimal tear and differential flow velocities. AJR 1986; 146:1286-1288. Glazer HS, Gutierrez FR, Levitt RG, Lee JKT,

contrast 5, Harada I. Aortic dissecintimal rupture: diagnosis with and CT. Radiology 1988; 168:

T, Tada

tion without MR imaging 57.

ing. Radiology Geisinger MA,

Fruehwald

D, Fisher

MR, Higgins

pit-

section: sensitivity and specificity aging. Radiology 1988; 166:651-655. Bogren HG, Underwood SR. Firmin DN, et a!. Magnetic resonance velocity mapping in aortic dissection. BrJ Radio! 1988; 61:456-462. Amparo EG, Higgins CB, Hricak H, Sollitto R. Aortic dissection: magnetic resonance imag-

surgery. 982-989.

156:39-43. 56.

dissection:

in MR imaging.

1990; 177:223-228. Kersting-Sommerhoff

CB.

Muller

55.

artifacts

aortic

Cine-MR in dissection of the thoracic EurJ Radiol 1989; 9:37-41.

EH,

imaging

Radiology

Thoracic

Preoperative evaluation of the thoracic aorta using M and angiography. Ann Thorac Surg 1987; 44:499-507. 77.

Moore

R, Brady

AA.

152:95-101.

WR,

EJ, Thompson

LeeJKT.

Murphy

Radiology

149:9-13.

RD. Sommerhoff

MR

91

93.

Radiology

Glimelius

Residual mediastinal masses ease: prediction of size with diology

in the

of fibrosis.

RH, Firmin DN, et assessment of aortic Br HeartJ 1986; 56:

69.

70.

imaging.

ital abnormalities

92.

falls and

165:

MR

Fletcher

1982;

TJ, et al.

at 1.5 1. Ra-

treatment 235-240.

tion of the aorta: 1986; 158:469-474. 90.

to-

Tomogr

unpost-

Didier

Ejection fraction determination by MR imaging: comparison with left ventricle angiography. Radiology 1986; 158:775-777. Solomon SL, Brown JJ, Glazer HS, Mirowitz

SA,

Controversy

appearance

by computed

Assist

RJ. Coarctation of the aorta in children dergoing angioplasty: pretreatment and

Katz ME, Glazer HS, Siegel MJ, Gutierrez F, Levitt RG, Lee JKT. Mediastinal vessels: postoperative evaluation with MR imaging. Radiology 1986; 161:647-651. von Schulthess G, Higashino SM, Higgins 55,

89.

68.

721-726. 47.

dissection

J Comput

6:750-756. Underwood SR, Klipstein al. Magnetic resonance and mitral regurgitation.

neurofibro-

Glazer HS, Lee JK, Levitt RG, et al. Radiation fibrosis: differentiation from recurrent tumor by MR imaging. Radiology 1985; 156:

aortic

88.

455-462. Stratemeier

magnetic 1991; 12:

E, Latchaw

Spinal and paraspinal

matosis:

67.

Wochenschr

IGermanl DP. Thoracic Clin Chest Med

JC, Naidich imaging.

WolfGL.

64.

Thymic 155:495-

T, Trampe resonance an alternative

Weinreb resonance 33-54.

45.

46.

G. and

148:515-519.

1988; 113:1508-1510. 44.

Gamsu with MR

ogy 1986; 158:313-317. Molina PU, Siegel MJ, Glazer [IS. masses on MR imaging. AIR 1990; 500. Batra P. Herrmann C, Mulder D. nal imaging in myasthenia gravis: of chest radiography, CT, MR, and findings.

43.

WR,

ogy. J Thorac Imaging 1990; 5:40-47. Stanford WI-I, Sykers RG, Weens HS. Problems in the aortographic diagnosis of dissecting aneurysms of the aorta. N EngI J Med i%9; 280:225-231. Godwin JD. Conventional CT of the aorta. J Thorac Imaging 1990; 5:18-31. White RD, Dooms GC, Higgins CB. Advances in imaging thoracic aortic disease. Invest Radiol 1986; 21:761-778. Godwin JD, Breiman RS, SpeckmanJM, Problems and pitfalls in the evaluation of

injury.

Radiology

1980;

105.

106.

136:141-

146. Heiberg E, Wolverson MX, Sundaram M, ShieldsJB. CT in aortic trauma. AJR 1983; 1401119-1124. Moore EH, Webb WR, Verrier ED, et at. MRI of chronic post-traumatic false aneurysms of the thoracic aorta. AIR 1984; 143:1195-1196. Bank ER, Aisen AM, Rocchini AP, Hernandez

107.

108.

NFl,

Cheitlin

Kersting-Sommerhoff

DF, et al. congenital

MD.

Congenital

BA, Dietheim

L, Teitel

Magnetic resonance imaging heart disease: sensitivity and

ificity

using

curve

analysis.

receiver

operating

Am Heart

of spec-

characteristic

J 1989; 118:155-161. Radiology

#{149} 629

109.

Park JH, Han MC, Kim CW. MR imaging of congenitally corrected transposition of the great vessels in adults. AIR 1989; 153:491-494.

129.

I 10.

Rees S. Firmin D, Mohiaddin R, Uongmore D. Application

130.

surements mapping II I.

112.

by magnetic to congenital

in massive

lipomatous

Am J

septum.

et

hypertrophy Cardiol 1987;

131.

RA, Weyman

AE,

tissue

Dinsmore

of

Go R, O’Donnell

myxomas.

Dooms CC, diac thrombi.

Higgins

CB.

Assist

118.

119.

120.

121.

122.

123.

Freedberg beskind

D.

et a!.

of car-

Tomogr

imaging

tracardiac

tumors

134.

135.

136.

1986; Lie-

Laissy JP, Bernier P. Patrux B, et al. Primary left atrial angiosarcoma: follow-up by magnetic resonance imaging. Magn Reson Imaging 1990; 8:651-655. Amparo EG, Higgins CB, Farmer D, Gamsu

Gated

MRI of cardiac

paracardiac masses: initial 1984; 143:1151-1156. Casolo F, Biasi 5, Balzarini

experience.

to echocardiography

J

5, van

M, Higgins

CB.

Suspected

127.

128.

Keller PJ, Hunter WW Jr. Schmalbrock Multisection fat-water imaging with shift selective presaturation. Radiology 164:539-541.

Clover GH, Schneider E. technique for true water/fat with

Reson

B, inhomogeneity

Med

Venous

imaging.

152.

Radiology

TW, Cunningham

FG,

153.

CE, Sostman

RE.

Deep

HD,

venous

141.

Wilkes

DC,

Cole-

Brenner

B, Marder

of fern-

VJ, Bryant

RG.

imaging

Ernerg

deep

Med

155.

156.

157.

WA,

Parkey

venous

Yousem

RW.

thrombosis

MR images: AJNR

imaging

Lund

F, Diener

J, Debrum thrombus

potential

168:

McMurdo

C, Gamsu

masses:

MR

KK, Tschola-

CB.

G, Higgins imaging.

Radiology

McMurdo KK, de Geer C, Webb WR, Gamsu C. Normal and occluded mediastinal veins: MR imaging. Radiology 1986; 159:33-38. Hansen ME, Spritzer CE, Sostman HD. As-

Haire WD, RP, Edney

Lynch TG, Lund IA. Limitations

nance

imaging

plex)

scanning thrombosis.

and

ultrasound-directed

in the

J

GB, Lieberman of magnetic reso-

diagnosis Vase Surg

(du-

of subclavian 1991; 13:391-

Ebner F, Kressel mor recurrence

FlY, Mintz MC, et al. Tuversus fibrosis in the female pelvis: differentiation with MR imaging at 1.5 1. Radiology 1988; 166:333-340. Armington WG, Harnsberger HR, Osborn AG, Seay AR. Radiographic evaluation of brachial plexopathy. AJNR 1987; 8:361-367.

Lederman

chial

of

RJ, Wilbourn

recurrent

cancer

AJ.

Brachial

or radiation?

plexopNeurol-

plexus

in patients

with

1983; 33:1553-1557. KS, Glazer GM, Gebarski

plexus:

anatomic,

cancer.

SS.

radiologic

and

Brapatho-

using computed tomograAssist Tomogr 1982; 6:1058-

161.

Rapoport S, Blair DN, McCarthy SM, Desser IS, Hammers LW, Sostman HD. Brachial plexus: correlation of MR imaging with CT and pathologic findings. Radiology 1988; 167:

162.

Gupta RK, Mehta VS. Banerji AK,Jain RK. MR evaluation of brachial plexus injuries.

1990;

GM,

161-165.

in flow

11:51-58.

163.

176:

U, Ericsson thromboembolism.

Bettmann

Paulin

S.

Leg

clinically

modification

the incidence,

nature

and

desirable

effects.

Radiology

side

101-104. Hull RD. Hirsch

ph!ebography:

AWA,

Prandoni

P. Brandjes

Shuman

WP.

brachial

149:1219-1222. Knee!andJB,

GM,

MR imaging

plexus

in

tumor.

Keilman

167.

al. MR imaging of the supraclavicular region: normal anatomy. AIR 1987; 148:77-82. Krteeland JB, Kellman GM, Middleton WD, et al. Diagnosis of diseases of the supraclavicular region by use of MR imaging. AJR 1987;

1977; 122:

Sackett DL, Stoddart G. Cost-effectiveness of clinical diagnosis, venography, and noninvasive testing in patients with symptomatic deep-vein thrombosis.N EnglJ Med 1981; 304:1561-1567.

AA,

suspected

166.

of un-

J,

of

Castagno

Angiology

AJR 1987;

MA,

Imaging

165.

J.

Postmortem as an aid in stud-

1989; 31:377-381. V. Hentz VR.

164.

sequence:

1990;

Neuroradiology Roger B, Trewers

post-traumatic brachial plexus injury. Clin Orthop 1988; 137:57-61. Blair DN, Rapoport 5, Sostman HD, Blair OC. Normal brachial plexus: MR imaging. Radiology 1987; 165:763-767.

1969; 20:155-176.

Lensing

CK,

the brachial

on

pitfall

phlebography

ies of venous

147.

is “gold

Neurology Gebarski

AJR 1990;

gradient recalled pulse experience. Radiology

intraosseous

Magn

venous thrombosis: still the diagnostic Radiology 1988;

160.

255-262.

146.

Schulthess

logic correlation phy.J Comput

Spritzer CE, Peic NJ, LeeJN, Evans AJ, Sostman HD, Riederer SJ. Rapid MR imaging of blood flow with a phase-sensitive, limitedflip-angle, preliminary

145.

1990;

159.

venous

(letter).

Hyperintense

evaluation.

intracar-

corn-

Radiology

ogy 1984; 34:1331-1335. Kori SH, Foley KM, PosnerjB. Brachial plexus lesions in patients with cancer: 100 cases. Neurology 1981; 31:45-50. Cascirio TL, Kori 5, Krol G, Foley KM. CT of

158.

1991; 20:497MR

DM, Balakrishnan RN.

GRASS

144.

Out-

normal

1063.

499. Erdman

Bryan

der

von

athy:

155:897. 142.

CS.

with

397.

in 66

Diagnosis

for calf

Ann

Redman HC. Deep contrast venography standard”? (editorial).

vein

experi-

ence with gradient-echo MR imaging patients. Radiology 1990; 177:235-241. Totterman 5, Francis CW, Foster TH,

deep

154.

gradientexperi-

thrombosis:

JJ, Dorfman

sessing the patency of mediastinal and thoracic inlet veins: value of MR imaging. AJR 1990; 155:1177-1182.

1988; 166:371-375.

Radiology

Spritzer

Radi-

1986; 158:289-296.

C, Camp-

with limited-flip-angle, MR imaging: preliminary

thrombosis.

Three-point Dixon decomposition

correction.

1991; 18:371-383.

Lowe

MR

in diagnosis.

of patients

Mediastinal

of MR imaging in the diagnosis. Radiology 1990; 174:425-431. Spritzer CE, Sussman 5K, Blinder RA, Saeed M, Herfkens RJ. Deep venous thrombosis

resonance

Radiol

P. chemical 1987;

with

JP, Cronan analysis

koff D, de Geer

140.

as

diac masses: evaluation with MR imaging. Radiology 1987; 165:117-122.

151.

MR

JC.

imaging

277-278.

giographic der tiefen bein-und beckenvenenthrombose: vergleich mit der phlebographie. Fortschr Rontgenstr 1990; 153:654-657. Vukov LF, Berquist TH, King BF. Magnetic

for the diagEur

150.

139.

and

MRI

CEL,

Pope

flow

pression US examinations. 175:645-649.

oropopliteal venous thrombosis with MR irnaging: a comparison of four MR pulse sequences. AJR 1990; 154:175-178. GehI V, Bohndorf K, Gunther RW. MR-an-

143.

nostic imaging of cardiac masses. 1988; 8:226-230. de Roos A, Weijers E, van Duinen

Winkler

138.

AJR

U, et al.

Brown

HD,

W, Gore

Vaccaro come

Weinreb JC. Puerperal pelvic thrombophlebitis: impact on diagnosis and treatment using x-ray, CT and MR imaging. Obstet Gynecol 1986; 68:789-794. Erdman WA, Jayson H, Redman H, et a!. Deep venous thrombosis of extremities: role

man

Wall EE. Calcified right atrial myxoma demonstrated by magnetic resonance imaging. Chest 1989; 95:478-479. 126.

137.

by echocardi-

imaging. AIR 1989; 152:469-473. Hananouchi Gl, Goff WB II. Cardiac lipoma: six-year follow-up with MRI characteristics, and a review of the literature. Magn Reson Imaging 1990; 8:825-828.

M.

5, Sostman

ence.

of in-

nant cardiac fibrous histiocytomas and angiosarcomas: MR features. J Comput Assist To-. mogr 1989; 13:627-632. Barakos JA, Brown JJ, Higgins CB. MR imaging of secondary cardiac and paracardiac Icsions. AIR 1989; 153:47-50. Lund JT, Ehman RU, Julsrud PR, Sinak U, Tajik AJ. Cardiac masses: assessment by MR

an adjunct

125.

diagnosed

Rapoport

evaluation refocused

ography. Circulation 1988; 77:96-103. Kim EE, Wallace 5, Abello R, et al. Malig-

G, McNamara

124.

to the evaluation

149.

1986; 161:233-238.

evaluation 162:527-530.

RS, Krozon I, Runnancik WM, The contribution of magnetic

resonance

Radiology

clots: 1987;

10:415-420. 117.

and

diagno-

MR imaging

J Comput

experimental

clinical

CM, Holcomb

Comparison of gated cardiac MRI and 2D echocardiography of intracardiac neoplasms. AJR 1985; 145:21-25. 116.

thrombosis:

duplex

ology 1990; 175:639-644.

1985;

Cohen JM, Buja RM. Venous

utaro

DA,

Radiology

Erdman WA, WeinrebJC, UM, Chancy C, Peshock

RE, et al.

Radiology

JK, Underwood

MR imaging.

Rose SC, Zwiebel WJ, Nelson BD, et al. Symptomatic lower extremity deep venous thrombosis: accuracy, limitations, and role of color

perfusion 98:891-899.

lung scan. Ann Intern Med 1983; Braun IF, Hoffman JC, Malko JA, Pettigrew RI, Donnels W, Davis PC. Jugular venous

imaging.

59:489-

characterization:

abnormal

with

148.

157:357-360. 132.

sis of lipomatous hypertrophy of the atrial septum by nuclear magnetic resonance testing. J Am CoIl Cardiol 1986; 7:688-692. Conces DJ, Vix VA, Klatte EC. Cated MR

imaging of left atrial 1985; 156:445-447.

embolism

thrombosis:

133.

491. Levine

Noninvasive

115.

monary

Applegate PM, Tajik AJ,Julsrud PR, Miller RA. Two-dimensional echocardiographic and magnetic resonance imaging observathe atrial

114.

resonance velocity heart disease. Am

Cardiol 1989; 64:953-956. Naidich DP, Rumancik WM, Ettenger NA, al. Congenital anomalies of the lungs in adults: MR diagnosis. AIR 1988; 151:13-19.

tions

113.

R, Underwood of flow mea-

Alderson P0, Martin EC. Pulmonary embolism: diagnosis with multiple imaging modalities. Radiology 1987; 164:297-312. Hull RD. Hirsch J, Carter CJ, et al. Pulmonary angiography, ventilation lung scanning, and venography for clinically suspected pul-

Middleton

WD,

et

148:1149-1151.

D, et al.

Detection of deep-vein thrombosis by realtime B-mode ultrasonography. N EnglJ Med

1989; 320:342-345.

630

#{149} Radiology

March

1992