fist

is clenched,

across

the

a compressive

midcarpal

ics.

force

joint

J Bone

ted by the head of the capitate to the scapholunate space, which may become wider than 2 mm in cases of scapholunate instability. U

2.

Moheim MS. nor radiograph nate

We

MD, for his advice investigation.

and

thank

Louis

cooperation

1981; 3.

Frot

during

JY,

R.

Visualisation

classification

and

5.

Data

were

three-dimensional ed (fast imaging

acquired

with

a

velocity-compensatwith steady-state pre-

sequence.

tissues

(sinus

vascular

Index

terms:

ies,

MR angiograms

trast

and

were

nasal

mucosa)

can ob-

detail. Cerebral

blood vessels, MR studresonance (MR), con-

#{149} Magnetic

17.1214

d’une Ann

Campbell and

scaphoid

I

1990;

M,

Chir

Bena-

sca-

From

the

diological

Medical ceived

280

RSNA,

30,

received

Radiology

#{149}

Nashville, 1989;

5. Address address: Hospital, 1990

of Radiology

Vanderbilt

Center, May

27; revision December 2 Current Lee County C

Department

Sciences,

revision November

and

Ra-

University

TN 37232-2675. requested 20;

ReJune

accepted

reprint requests to J.L.C. Department of Radiology, Fort Myers, Florida.

DM,

WA.

incidence

The

wrist

the

J Bone

its

1988;

sprained

diagnosis

Clin

In: and

Saunders,

Beware and

instability.

1986;

instability.

ed.

Philadelphia:

273. Jones

8.

incidence Main

Scapholunate

sign.

disor251-

wrist:

the

of scapholunate

Joint

Surg

[Br]

PM.

Post-traumatic

1988;

bone.

RD

Jr. Arnold

secondary

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9.

dislocation

Joint

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of

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LA,

mentous

[Br]

1978;

Weeks instability

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ligaRadiology

129:641-651.

J. Scapholunate J, ed. The wrist.

dissociation. New York:

In: Chur-

Anglography’

variety of different methods for magnetic resonance (MR) angiography have been employed to noninvasively visualize vascular anatomy, without the use of MR contrast agents (1-3). A concise summary of the phys-

mens, Iselin, NJ). In all cases, these data were acquired with a three-dimensional velocity-compensated FISP (fast imaging with steady-state precession) sequence provided by Siemens as part of

ics

software package. The sequence parametcrs included a flip angle of 20#{176}, a repetition time (TR) of 40 mscc, an echo time (TE) of 8 mscc, one acquisition, and a 256 X 256 image matrix with 64 sections or partitions. The 20#{176} flip angle was chosen to give maximum vessel contrast due to inflow effects, 40 msec was the minimum TR possible without image distortion, and 8 msec was the minimum TE possible for the pulse sequence. The slab thickness for the 64 partitions varied from 80 to 200 mm, resuiting in an effective section thickness of 1.25-3.125 mm. The in-plane pixel dimension was 1 X 1 mm. A transmitreceive head coil was used in all instances. After acquisition of the initial three-dimensional image data set, GdDTPA was administered at a dose of 0.1 mmol/kg over a 1-2-minute interval; within 10 minutes of the injection, the imaging sequence was repeated. After the data acquisition was completed and each of the 64 sections rcconstructed, separate MR angiograms of the pre- and postcontrast data sets were formed by the maximal value ray projection technique described by Laub and Kaiser (9). Each parallel ray, when projected on the viewing plane, carries with it a maximum intensity that it intersected in its path through the imaging volume (stack of sections). The precontrast planar images and projection MR angiographic views were compared by two participants (J.L.C., T.P.) with similar images obtamed after contrast material injection. The evaluation included an assessment

related

to

the

depiction

of flowing

blood is given by Gao et al (4). MR angiographic methods have included both two-dimensional (5) and three-dimensional (6,7) techniques. Intravascular MR contrast material, in the form of albumin labeled with gadolinium diethylenetniaminepcntaacctic acid (DTPA), has been used experimentally in rats in conjunction with projection imaging (8). After performing unenhanced MR angiography for a limited period of time, primarily for vascular lesions, we observed an interesting finding in a case in which Gd-DTPA dimeglumine (Magnevist; Berlex, Cedar Knolls, NJ) had been administered to enhance tumon

tissue.

When

the

MR

angiographic

pulse sequence was used there was some improvement in the depiction of the vascular anatomy on both the mdividual images and on the projection MR images.

Materials

175:280-283

G.

Lichtman

enhancement

Radiology

Blatt

239-279.

The Terry-Thomas 129:321-322.

46:73-82.

MR

obtained with a ray projection algorithm by using maximum intensity values. Portions of the vascular anatomy particularly venous structures and smaller arteries - were better portrayed on the postcontrast than on the precontrast angiograms. Enhancing lesions were also seen on the projection images. Enhancement of dura and extracranial scure

D, David

de l’interlingne

simple. TL,

Taleisnik

Experience in three patients (one each with meningioma, pineal tumor, and prominent jugular bulb) illustrates that magnetic resonance (MR) angiography can benefit from the administration of gadolinium diethylenetriaminepenta-

cession)

7.

[Am]

1985;

VH. 1977;

70:293-297.

Taleisnik

pathomechan-

Jeff L. Creasy, MD Ronald R. Price, PhD Thomas Presbrey, MD2 David Goins, RT C. Leon Partain, MD, PhD Robert M. Kessler, MD

acid.

Folinais

description

Primary

1964;

Gadolinium-enhanced

acetic

Surg

Livingstone,

Frankel Orthop

ders.

B, Alnot

Thompson the

RS.

chill 6.

5:335-338.

RL, Dobyns JH, Beabout JW, BryTraumatic instability of the wrist:

diagnosis,

54:1612-

posteroantescapholu-

J Bone Joint

radiologique

this

References an

1972;

63:1324-1326.

WD.

Linscheid

[Am]

The tangential to demonstrate

pho-lunarien:

Gilula,

4.

1.

Surg

dissociation.

ceraff

Acknowledgment:

Joint

1632.

is transmit-

and

Methods

In three patients MR angiography was performed both before and after intravenous injection of Gd-DTPA. One patient had a meningioma; one, a pineal tumor; and one, a prominent jugular bulb. Two patients (one with a pineal tumor and one with a meningioma) were studied to assess to vascularity of a lesion and its relationship to nearby arteries and veins. The patient with a prominent jugular bulb was studied primarily

to view

the

vascular

tree

it-

self. Studies

MR

imaging

were

performed

system

on

(Magnetom;

a 1.5-T

Sic-

its

of

investigational

the

sions

MR

ability

to

on the

MR

angiography

visualize

angiogram,

enhancing

le-

to detect

April

1990

a.

ative MR imaging examination. MR angiography without Gd-DTPA enhancement was performed in axial sections and demonstrated minimal venous anatomy. The Gd-DTPA-enhanced MR angiography, performed with sagittal sectioning, showed additional deep yenous anatomy, including the thalamostriate veins, internal cerebral veins, vein of Galen, straight sinus, and supenor sagittal sinus. The third patient was referred for evaluation of a temporal lobe lesion seen at CT; this was believed to be only a prominent jugular bulb. An MR cxamination was requested and included MR angiography for confirmation of the tentative diagnosis (Fig 3). A prominent, high-rising right jugular bulb was indeed present on the anteropostenor projected MR angiograms. In addition, the Gd-DTPA-enhanced MR angiogram demonstrated more venous structures in the neck and more distal branches of the anterior and middle cerebral arteries. As in the other two patients, some extravascular enhancement was present extracranially.

b.

Discussion

d.

C.

Figure 1. Images of a 45-year-old woman with a known left parasellar meningioma. Planar Gd-DTPA-enhanced axial image (TR, 750 msec; TE, 20 msec) (a) and three-dimensional FISP image (b) show enhancement of the tumor. Projection angiograms obtained before (c) and after (d) administration of contrast material. The postcontrast image demonstrates the tumor (arrows)

any

and

vessels

additional

visualized

administration fore administration, luminal

posterior

areas

after

that that

fossa

venous

Gd-DTPA

were and

not visible beto note extra-

artifactually

en-

was

improved

Results

delineation

of

the

mid-

die cerebral artery and A2 segments

branches and of the anterior

bral

enhancing

meningio-

left area

sphenoid was clearly

the

vasculature.

arteries.

ma along

hanced.

ridge

and

visible

in

The

the medial parasellar relation

to

Al cere-

Overlying

Portions of the vascular anatomy can be better visualized after Gd-DTPA enhancement (Figs 1-3). In the patient with the meningioma (Fig 1), GdDTPA-enhanced MR angiography depicted the vein of Galen, straight sinus, and cortical veins not seen before contrast material administration. There

Volume

structures.

175

#{149} Number

1

pharynx

The known findings (CT). assess to the

quested

enhancement of the nasowas also present. pineal region tumor (Fig 2) was to be present on the basis of from computed tomography MR angiography, performed to the position of the mass relative deep

venous

in conjunction

system,

was

with

re-

a preoper-

Unenhanced MR angiography is being promoted for use in a number of neurologic conditions; vascular occlusions, atherosclerotic disease, and ancurysms have all been evaluated in prelimmnary studies (6,7,10). Masaryk et al concluded that a good intravascular contrast agent would benefit the technique of MR angiography (6), and they referenced the work on albumin GdDTPA complexes by Schiedl et al (11,12). To our knowledge, however, none of the work to date has discussed the routine use of Gd-DTPA itself (as opposed to albumin Gd-DTPA) for three-dimensional volume-acquired MR angiographic studies. Theoretical basis of Gd-DTPA-enhanced MR angiography.-The FISP three-dimensional MR angiographic pulse sequence employs gradient motion refocusing to rcphase spins flowing at a constant velocity(s). The result is the depiction of blood vessels by means of the inherent contrast of “stationary” blood. Additional contrast is achieved by time-of-flight effects. These effects are most obvious with vessels oriented perpendicular to the sections and with larger flip angles (20#{176}-30#{176}). Because of the short TE (8 msec) of this sequence, the accumulated phase errors due to acceleration effects were relatively insignificant (