Cardiac Markus Jungehulsing, Hans Hermann Hilger,

MD MD

#{149} Udo

Sechtem, MD #{149} Peter Schicha, MD

Thrombi: Gradient-Echo

Gradient-echo (GRE) and spin-echo (SE) magnetic resonance (MR) imaging was performed in 3i patients with chronic left ventricular (LV) thrombi. Thrombi were confirmed or excluded at surgery or by means of other corroborative diagnostic techniques. MR images were evaluated by three reviewers without knowledge of results of corroborative studies. Diagnoses were graded unequivocal if agreed on by three observers and probable if agreed on by two observers. With SE imaging, i2 of iS confirmed thrombi were detected unequivocally, five were considered probable, and one was not detected. With GRE imaging, i6 of the 18 thrombi were visualized unequivocally; two were considered probable. With SE technique, thrombus was unequivocally excluded in nine of 13 cases and exclusion was considered probable in four. One finding was false-negative. Exclusion of thrombus with GRE imaging was unequivocal in 10 of 13 cases and probable in two, and one finding of thrombus was false-positive. GRE imaging resulted in improved differentiation of thrombi from the surrounding blood pool and myocardium and thus was diagnostically superior to SE imaging in detection of LV thrombi. Index terms: Aneurysm, cardiac, 524.773, 524.775 #{149} Heart, MR. 524.1214 #{149} Heart, thrombosis, 524.731, 524.775 #{149} Magnetic resonance, comparative studies #{149} Thrombosis, MR. 524.1214 1992;

MD

#{149} Harald

Left Ventricular Spin-Echo and

Radiology

Theissen,

182:225-229

I

Evaluation with MR Imaging’

patients with left ventricular (LV) aneurysms, embolism is a complication that causes considerable morbidity (1,2). Detection of thrombi in these patients has important consequences; immediate institution of anticoagulant therapy may reduce the possibility of systemic embolism (3,4). Methods such as LV angiography, scintigraphic techniques, computed tomography (CT), and two-dimensionab echocardiography (7) arc used clinically to detect thrombi (4-7). The advantages that two-dimensional echocandiognaphy has over the other mentioned techniques are portability, unlimited imaging planes, bow cost, and noninvasiveness, combined with reasonable sensitivity and specificity. Another noninvasive technique for detecting LV thrombi is magnetic nesonance (MR) imaging. The value of spin-echo (SE) MR imaging in the dctection of LV thrombi has recently been shown (8-10). Gradient-echo (GRE) MR imaging of the heart has added important dynamic information to the morphologic detail demonstrated by SE MR imaging (11-13). GRE MR imaging also is capable of enhancing the signal intensity of flowing blood and thus enhancing contrast between blood and myocandium, especially in patients with slow intraventricular blood flow (14,15). Therefore, the purposes of this study were to evaluate the appearance of LV thrombi on GRE images and to compare the diagnostic value of SE and GRE MR imaging for the diagnosis or exclusion of LV thrombi in pa-

PATIENTS

N

tients

with

LV

aneurysms.

AND

Thirty-one

women,

patients (22 men and nine years old) with chronic underwent SE and GRE

36-77

LV aneurysms

MR imaging.

Thrombi

18 patients

and

cepted M.J. (:

the Clinic and Outpatient Medicine Received

July 15. Supported

RSNA,

1992

Clinic

for Nuclear

Medicine

(U.S., H.H.H.), Universit#{228}t zu KOln, January 29, 1991; revision requested

by the Deutsche

(M.J., PT., H.S.) and the Third

Address

reprint

in

requests

confirmed

in

13 patients

at

on by techniques.

use of Sungi-

cal confirmation was available in 13 patients. Confirmation or exclusion in all other patients was accomplished by con-

roborative diagnosis with the following techniques: sional

at least two of two-dimen-

echocardiography

(n = 5), and (Table).

MR

Imaging

Proton

(ti

(n

CT 15)

=

Technique

MR

imaging

was

with a superconducting at 1.5 T (Gyroscan; erbands).

18),

=

LV angiography

SE MR

performed

magnet Philips, Best,

imaging

was

operating The Neth-

performed

with electrocardiographic gating and two echoes with echo times (TEs) of 30 and 60 msec. Repetition time (TR) ranged from 470 rate

to 1,060 msec, of the patient.

depending The heart

on the heart was imaged

from the LV apex to the aortic root in transverse sections with 8-mm thickness and 0.8-mm gap. The image matrix was

128 x

256

pixels.

To

improve

visualization

of the intracardiac anatomy and to simplify differentiation of flow effects that may occur only in one imaging plane, obbique sagittal sections with 8-mm section thickness were interventricular

performed

obtained septum.

parallel Angulation

by electronic

to the was

axis rotation.

Spa-

tial presaturation was not available at the time the study was conducted and could therefore not be used. GRE images were acquired by using prospective electrocardiographic and TRs of 26-30 msec with angle

compensation

was of blood for

gating TEs of 13

40#{176}. To signal

constant

improve intensity, velocities

Clinic

Joseph Stelzmann Strasse 9, 5000 Cologne March Ii; revision received July 10; ad-

Fonschungsgemeinschaft.

were

excluded

surgery (aneurysmectomy) corroborative imaging

flow

From

METHODS

Patients

msec. The flip the homogeneity

for Internal 41, Germany.

Radiology

to

Abbreviations: left ventricular, spin echo, TE time.

=

GRE = gradient echo, LV = ROI = region of interest, SE = echo time, TR = repetition

was employed as described previously (16). Section thickness of transverse 5cclions

was

8 mm

with

a 1.6-mm

gap.

The

heart was imaged from the LV apex to the base. Sagittal sections were obtained paralbcb to the intervcntricular septum as with the SE technique.

Image

Interpretation

SE and

GRE

images

were

interpreted

by

three independent observers who had no knowledge of the results of corroborative studies.

GRE

images

were

reviewed

in a

movie loop that could be stopped to allow closer observation and measurement of details on still frames. MR imaging findings were graded unequivocal if the three independent observers made the same diagnosis.

If only

two

observers

agreed,

the diagnosis was regarded as being only probable. Thus, there were four diagnostic categories: unequivocal thrombus, probablc thrombus, probably no thrombus, and unequivocally no thrombus. To characterize the contrast among blood, thrombus, and myocardium, signal intensity of thrombus, blood, myocardium, and cpicardial fat was measured in each patient by using regions of interest (ROIs) on transverse sections. ROI area was at beast 10 pixels, and ROIs were positioned in close proximity to thrombus. Signal intensity

was

measured

on

ob-

SE images

tamed with either TE and on GRE images obtained at systobc and diastobe in all patients

in whom

thrombus

cabby diagnosed aging

(n

=

with

12).

Signal

related to fat because dependence of signal terval.

Statistical

was

unequivo-

SE and GRE MR imintensities

were

of the well-known intensity

on

TR

in-

of parts of the thrombus relative to the myocandial wall (17). On second-echo images, slowly flowing blood within the LV ancunysm had higher signal intensity than did thrombus and myocardium in 10 of ii patients with recognizable thrombus. In one patient, flow signal intensity prevented visualization of a thrombus (Fig 3). The presence of sunrounding high-intensity slow blood flow usually facilitated the diffcnentiation between blood and thrombus. Signal intensity of thrombus was darker than that of flowing blood in eight patients. Mean signal intensity of thrombus was significantly lower than that of blood (P = .01) (Fig 4). Three thrombi, however, were brighter than surrounding blood, which was probably because of a nebatively high flow velocity and low blood flow signal intensity as a result of the smaller myocandiab lesions in these patients. Differentiation between thrombus and myocardium was more difficult. Seven thrombi were brighter than myocardium and four were slightly darker, and there was no constant signal intensity relation (P = .29, paired t test). In three patients, diag-

techniques

nosis

in five

patients.

With

both

techniques, diagnosis was false in one of these five. One patient had a false diagnosis of probable thrombus excbusion with SE images and a correct unequivocal diagnosis of thrombus with GRE images.

Analysis

Relative signal intensities of thrombus, blood, and myocardium were compared by using the paired t test and the Bonferroni correction for multiple comparisons. The distribution of unequivocal and uncertain diagnoses, as well as of the correct and false diagnoses with SE and GRE images, was compared by using the x2 test.

RESULTS Diagnostic GRE Images

Accuracy

of SE and

With SE MR imaging, unequivocal diagnosis of thrombus or absence of thrombus was possible in 21 of 31 cases (Table). In five cases, thrombus was considered probable; in another five cases, thrombus was not probable. Both of these categories included an incorrect diagnosis: one was falsepositive and one was false-negative. For the total of 93 diagnoses made by the three reviewers, SE image interpretation was correct in 81 (87%) and incorrect in 12 (13%). The GRE movie 226

allowed better visual distinction of thrombi from moving blood than did comparison of still SE images. GRE images were preferred for making the diagnosis in 87 of 93 paired observations. In 26 of 31 patients, GRE MR imaging results were unequivocal, and only five of 31 were uncertain (vs SE technique, x2 = 3.7 and P = .05). Among these five, one false-positive diagnosis was made in a patient with a large anterior aneurysm. SE and GRE image quality in this case was decreased because of prominent breathing artifacts. Eighty-seven (94%) of the individual diagnoses made by means of GRE image interpretation were correct, and six (6%) were not. The number of false diagnoses per observer was significantly higher with SE images than with GRE images (x2 = 6.4, P = .01). No diagnostic errors occurred in the 19 patients in whom all three observers formed the same diagnosis from SE or GRE MR images (Table). GRE diagnosis was unequivocal in six patients that had a probable diagnosis with use of SE images (three with and three without thrombus). Diagnosis was considered probable with both

#{149} Radiology

Appearance Images

of Thrombi

of thrombus

was

possible

only

when information from oblique sagittab sections was added. In generab, differences in signal intensities between the measured structures on SE images were slight and varied in direction; therefore, no constant signal intensity relation existed on SE images.

on SE

On first-echo SE images, differentiation between thrombus and myocardium was difficult because slightly higher signal intensities (n = 7) of thrombi were encountered as often as were slightly bower ones (n = 5) (Fig 1). Although the differences in signal intensity between thrombi and blood were also slight, mean signal intensity of thrombus was slightly higher (P = 0.05, paired t test) (Fig 2). In three patients, thrombi had lower signal intensity than did blood. All of these patients showed large aneurysms of the left ventricle, and signal intensity features were probably due to prominent slow blood flow and back of complete signal extinction of the blood. Differentiation from blood in these cases was possible only because a small line of flow signal intensity mdicated the presence of an additional structure; this signal intensity was probably due to slight movement

Appearance Images

of Thrombi

on GRE

On GRE images, blood had higher signal intensity than did all other intracardiac structures on systolic and diastolic images, and thrombus abways showed a bower signal intensity than did blood (P < .01) (Fig 5). The contrast between thrombus and blood was therefore consistent in all cases, which facilitated the identification of the 16 thrombi detected on GRE images. Of the 16 thrombi, ii had signal intensity bower than that of myocardium, three had nearby the same signab intensity, and two had signal intensity intermediate between those of blood and myocardium. In general, thrombus was the structure with the lowest signal intensity (P < .02, Bonfcrroni t test). LV aneurysms were more clearly defined on GRE images, due to the absence of wall thickening of the January

1992

Findings

and GRE MR Imaging

of SE

and Corroborative

Studies

in 31 Patients

with

LV Infarction

Chronic

MR Imaging Diagnosis of Thrombus Patient

No.

GRE

I 2 3 4 5 6

SE

Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal

7

8 9 10 11

Location Thrombus Confirmed

Exclusion Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal Unequivocal

probable*

of Thrombus in Myocardium

x x x x x x x x x x

Echo, Surgery Surgery Surgery Surgery Surgery Surgery Echo, Echo, Echo,

x

Echo, angio

angio

angio, CT anglo

Unequivocal

Unequivocal

Unequivocal

Unequivocal

x x

Echo, Echo,

14

Unequivocal

Probable

x

15

Unequivocal

Probable

x

16 17 18 19 20 21 22 23 24 25 26

Unequivocal Exclusion unequivocal

Unequivocal Exclusion unequivocal

Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Probable Probable Probable Exclusion Exclusion

Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Exclusion Probable Probable Probable Exclusion Exclusion

x

Surgery Echo, Echo, Echo, Echo, Surgery Echo, Echo, Echo, Echo, Surgery Surgery Surgery Echo, Surgery

x

Echo, angio

27 29

30 31 Note.-Angio * The thrombus t False diagnosis

thinned, dium.

=

unequivocal unequivocal unequivocal unequivocal unequivocal unequivocal unequivocal unequivocal unequivocal

probable probable

the

probable probable unequivocal unequivocal unequivocal unequivocal unequivocal unequivocal unequivocal

diagnostic

myocandid not

yield.

sionab flowing

The

sometimes

comparison of signal intensity quotients of thrombus versus fat, blood versus fat, and myocardium versus

fat

be confused

(21). In this improved

from the surrounding myocardium, because tween thrombus and

creased

tunes

significantly

on

GRE

images

was

all thrombi than that

DISCUSSION

for

nique,

another

noninvasive

because

studies

method for cardiac echocanthere is a

large

revealed

quality

MR images of thrombi

and bestnuc-

enhanced.

Sig-

was constant,

and

lower blood

to certain bus. For thrombi from

Volume

by

patients

relation. isointense

signal

even

characteristics

anatomic (18,19)

of the throm-

instance, laminated mural may be difficult to distinguish

myocardium

182

with

#{149} Number

two-dimen-

1

or

protruding laminar

Lange, Large, Lange, Small,

protruding laminar laminar protruding

Large,

laminar

Small, protruding

was

degraded

by prominent

breathing

Three with

intensity

greater

than

thrombi

with GRE images, because of the for the cine display of cardiac

motion

and

blood

flow.

In one

of that

two the

tion

between

flow

diac structures.

artifacts

Signal

was

five

patients

high signal-intensity bus. An alternate that these thrombi origin (22). The

certainty

led

to

spuriously

values explanation were of diagnosis

also

papillary

study,

we

have

shortening

used flip

of blood

or throm-

constant diastolic

signal im-

a GRE

flip

angles

of 20#{176} or

accentuated effects

intracanthe carsuch as

muscle

of 40#{176}. Shallower

the (15)

of the

T2*

anand

para-

magnetic compounds contained in the thrombus and further increased contnast between blood and thrombus. SE

for thromwould be

of more

inferior

30#{176} might 12

and

intensity

changed slightly during cycle, whereas structures

In our

diamag-

a

observers felt more comfortable making a diagnosis with GRE images, because the cine display simplified differentia-

gle

thrombi

of

patient,

freely movable thrombus was clearly depicted on GRE MR images, but was not diagnosed on SE images. In general,

were

myocardium,

artifacts.

proved capability

the

these

caused

Large, Large,

wall

flow diac

echocandiograms

the

sep-

CT

netic myocardium. It cannot be cxcluded that volume averaging of signal intensity of blood and thrombus in

of

Small, protruding

Apex

false-positive, or equivocal findings are not uncommon. Those findings may be attributable to technically inadequate abnormalities

sep-

bus maintained a nearly intensity on systolic and ages.

and

false-negative,

intenventricular

Comparison between the signal intensity of myocardium and that of thrombus on GRE images showed no

nearly

echocardiognaphic

that

Ant

thrombus

signal intensity surrounding

and lat wall wall wall

pool.

constant

tech-

had of the

and lat wall; apex and ant wall

protruding protruding laminar laminar protruding protruding laminar laminar laminar laminar

angio

blood pool the contrast surrounding

relation

Small, Small, Large, Large, Small, Small, Large, Large, Large, Lange,

angio angio angio CT

and slowmay

with

considerably

nab intensity

The primary screening patients with a suspected thrombus is two-dimensional diognaphy. Nevertheless,

CT angio angio angio

Image

study, use of GRE the differentiation

on SE and GRE MR images revealed that the difference between the signal intensity of measured structures in(Fig 6).

angio angio

echocardiography (20), blood in an aneurysm

wall

Apex;

Echo, angio, Surgery

probable probable

angiography, ant = anterior, echo = echocardiography, lat = lateral. was moving and therefore not detected with SE MR imaging. of large aneurysm of the anterior wall was made with both techniques.

infarcted anterior Sagittab GRE images

improve

x

CT

Ant Apex Ant Apex Apex Apex Ant Ant Ant Apex

Features of Thrombus

tum Ant wall Apex; interventnicular tum Apex; ant wall Apex Apex

12 13

28

need

Corroboration Techniques

MR

imaging

has

good

and specificity in detection thnombi (8). Nevertheless,

recent

image interpretation this method include

im-

largely

differing

values

sensitivity

of LV difficulties

in

encountered with motion artifacts, for

blood

Radiology

signal

#{149} 227

I

I

1-

I

P 0,05

-j--------

P

S

I

a. Figure

b.

1. 30) obtained

(a) Diagram in patient

thrombus

is lower

blood,

which

blood

appears

tnicular ventricle,

than

has

that

higher

intensity of cardiac features on (b) transverse SE section had LV aneurysm and laminar thrombus. Signal intensity

of myocandium

signal

=

echo

VCI

time,

and

intensity.

slightly darken than LV = left ventricle,

septum,

TE

of signal i5, who

=

The

does RA inferior

can be distinguished

remaining

thrombus. =

right

vena

from

intraventnculan,

AD

atrium,

descending ROIS = region =

slowly

flowing

normally

aorta,

IVS

of interest,

(740/ of

flowing intenven-

=

RV

=

Figure

3. (a) Diagram of signal intensity of cardiac features on (b) transverse section (740/60) obtained in the same patient as in Figure 1. The LV thrombus identified because of prominent flow artifacts. Signal intensity of thrombus not be measured. See Figure i for key to abbreviations.

right

I Ft

second-echo SE could not be could therefore

and during

ratio

more, there

resulting from a diminished the second

as demonstrated is no constant

the thrombus ond echoes.

There

blood flow yesignal-to-noise echo. Further-

in this study, signal intensity of

during

the

first

and

5cc-

T2-weightcd plexes such gbobin,

are several

potential

explana-

sections,

and

it was

therefore

always possible to measure dbc section, accomplishment would have avoided partial

ron. On the other

hand,

not

in the midof which volume en-

partial

volume

and sometimes calcifiboss of protons leads to intensity on Ti- and

MR images. as hemoglobin,

dcoxyhcmogbobin,

or fenritin

tions for the varying signal intensities of thrombus. First, partial volume effects from averaging thrombus and blood in the same section cannot be excluded. Thrombi often did not extend oven

three

iron complexes, cation (23). The decreased signal

show

Iron commethemohemosidenin,

different

magnetic

intensity

on T2-wcightcd A T2-wcighted

intensity

of thrombi

images

and signal images (24-27). sequence can be

organization.

un-

thus

as loss

tween blood.

of water, 228

An

aging

condensation

#{149} Radiology

changes

thrombus

such

of panamagnetic

with

in increased

achieved by gating to every second, third, or fourth heartbeat and might have accentuated the T2 shortening fect of the paramagnetic compounds

metabolic

thrombi,

however, therefore quence.

signal

boss

enhanced

thrombus and It is conceivable

contrast

be-

surrounding that the

more

because

used in this intensity of of some

undesin-

the

standard

GRE

and longer not employed Furthermore, would

have

sequence,

TR intervals were for the SE severy long TR inincreased

imaging

time considerably. Some thrombi were isointense myocardium or had even higher than

which was the infarct sult

the thrombotic material and reduced its signal intensity, whereas the echo rephasing effects would have intensifled the signal of slow blood flow and

possibly

tenvals

gbobin

efof

SE sequence to higher signal

able Ti shortening effects that made the distinction of thrombus from blood more difficult. The study was designed to evaluate the diagnostic potential of the standard SE sequence in companison

effects that may have contributed to diagnostic problems with use of SE mmages did not substantially interfere with diagnosis with GRE images, in which contrast between thnombi and the sunrounding blood pool was constant. Second, thrombotic material differs with respect to its age and degree of dergocs

some

characteristics: Oxyhemoglobin is diamagnetic, deoxyhemogbobin and methemoglobin are paramagnetic, and hemosidenin and fennitin are supenparamagnetic (22). Paramagnetic agents cause Ti and T2 shortening for tissues in which they are located, which results on Ti-weighted

I Ft

flI=d

Figure 4. Comparison (pained t test) of nelative signal intensities on SE MR images (TE, 60 msec) obtained in 11 patients. In general, blood showed higher signal intensity than did myocardium, whereas there was no consistent signal intensity relation between thrombus and cardiac structures.

Ti-weighted study led bocity,

/ F.,t

cava.

Th,=bs

intensity

IId

Ft

Figure 2. Comparison (pained f test) of nelative signal intensities in first-SE MR images (TE, 30 msec) obtained in 12 patients. Signal intensities of thrombus and myocardium were similar. There was no consistent nelationship in signal intensity among the three structures.

that

myocandium,

measured well away region. Paramagnetic

degradation in

of

signal

products loss

within

volume the age and

can

effect of the

be

attributed

of blood thrombi

hemoglobin

from hemo-

would the

which was indeed the case thnombi. The higher signal thnombus

with signal

in most intensity to

of

partial

or to the fact was unknown,

degradation

re-

thrombus,

that

products

could have been present in fresh thrombotic material, but in insufficient amounts to cause severe signal loss of the

thrombus

on

GRE

images.

January

1992

I Ft

Figure

6.

tensities a.

b.

Figure

5.

(a) Diagram

obtained

of signal

in the same

patient

intensity

patients

of cardiac

as in Figures

1 and

features

on

3. Thrombus

(b) transverse

outlines

GRE

are more

due to a marked difference in signal intensity of blood and thrombus. dium have similar signal intensity on this image and can be differentiated blood between them. See Figure 1 for key to abbreviations.

clearly

Thrombus by the

image

angle,

defined

among

MR

and thin

13.

its bow cost and

msec).

GRE sequences

Identification

ages slight sity

of thrombus

may also difference of

tunes

and

lack

relation

and

myocardium.

TE,

among

and

intensity

crabby

on

thrombus, Blood

phase

signal

images.

to vary

With

blood has consistently intensity in the absence which makes differentiation LV

study

indicates

thrombi

with

ated when addition to tients with prominent

GRE nor

to

MR

MR imaging SE

thrombi.

imaging

choice.

SE

omy

may

and

unknown quicker aging

the

left

5.

is used

imaging,

6.

of only

to

site, technique

7.

however,

overview

of cardiac be

anat-

of additional

of the infarcted

ventricle

would

Echocardiognaphy will primary imaging technique patients with LV aneurysms

8.

area

and must be determined than time-consuming GRE of

4.

to be supe-

detection

therefore

use if the extent

of

is facili-

seems

imaging

MR

a fast

1.

3.

are acquired in especially in paflow artifacts and flow.

at a prespecifled seems to be the

provides

imag-

is im9.

allow.

remain the to screen because

10.

of I 1.

Volume

182

#{149} Number

1

be

accurate

its diagnostic

further

enhanced

in patients

intraventricuban

14.

MR imag-

a noninvasive,

capabilby

with thrombus.

F.I

signal

in-

on GRE MR images

obtained

in 11

during

13 msec;

flip

diastole

40#{176}). Differences

structures

(TE,

in signal

intensity

are consistent.

use

Utz JA, Herfkens RJ, Heinsimer JA, et al. Cine MR determination of left ventricular ejection fraction. AJR 1987; 148:839-843. Haase A, Matthaei D, H#{228}nickeW, Merboldt KD. Flash imaging: rapid NMR imaging using low flip-angle pulses. J Magn Reson 1986; 67:258-266.

low-quality

however,

technique; can

for real-time

with

15.

of

susU

References

2.

detection

imaging

for

If MR

detect thrombi GRE imaging of

that

GRE images SE images, prominent slow blood

itics

can cause consid-

GRE

capability

patients

represents

second

higher signal of turbulence, easier.

ing,

Our

ing

pected

im-

velocity,

cycle

of blood

In

echocardiograms,

blood,

flow

of cardiac

SE

SE

be difficult because of the between signal intenand surrounding strucof consistent signal inten-

thrombus

sity

on

imaging.

/

of relative

myocarline of 12.

The third reason for inconsistent signab intensity may be the result of diffenent heart rates causing slightly different Ti weighting of SE images. In contrast, TRs are short and nearly constant for GRE imaging (variation, 25-27

I3I(1

Comparison

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Left ventricular thrombi: evaluation with spin-echo and gradient-echo MR imaging.

Gradient-echo (GRE) and spin-echo (SE) magnetic resonance (MR) imaging was performed in 31 patients with chronic left ventricular (LV) thrombi. Thromb...
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