479

Case Report

American Journal of Roentgenology 1992.159:479-480.

Anomalous Left Brachiocephalic MR Demonstration Kiminori

Fujimoto,1

Toshi

Abe,1 Tsutornu

The normal left brachiocephalic from

the confluence

Kurnabe,1

(innominate)

of the left internal

jugular

Naofumi

vein extends

left common

carotid,

and brachiocephalic

Rarely, scribed

this vein follows an anomalous course. as the anomalous left brachiocephalic

anomaly teristics

was first described have not previously

Because

arteries.

Embryologically,

at 1 -cm

intervals

with

(eighth week), municate blood

crossing the mediastinum to the right, posterior to the ascending aorta and anterior to the trachea (Figs. 1B and 1C). It then entered the superior vena cava inferior to the insertion of the azygos vein

the

1 D). The left brachiocephalic vein was not seen in its normal course. Coronal Ti-weighted MR images showed that this signal void extended from the junction of the left internal jugular and

September

1992 0361-803X/92/1

593-0479

© American

first

an oblique

cross

cardinal

channel,

anastomosis,

veins com-

the precardinal

which

passes

the

left

upper

aortic aortic

Received January 28, 1992; accepted after revision March 9, 1992. 1 Department of Radiology, Kurume University School of Medicine, 67 Asahimachi

AJR 159:479-480,

veins

to right. As a result of its diversion, the left cardinal vein proximal to the anastomosis atrophies

Normally,

(Fig.

Saint Mary’s Hospital, 422 Tsubukuhonmachi

or anom-

and loses its connection with the left common cardinal vein. The right common cardinal vein and the anterior cardinal vein as far as the precardinal anastomosis become the superior vena cava. The precardinal anastomosis itself and the left anterior cardinal vein distal to the confluence of the veins from

axial MR images, a round area of signal void was present lateral to the aortic arch (Fig. 1 A). This signal void passed downward and lateral to the aortic arch and entered the aorticopulmonary window,

of Radiology,

of the systemic

the right and left anterior transversal)

from

anterior

-

Department

malformations

treatment.

the primordia

through

(intercardinal,

1 -cm

slice thickness, while the patient was supine. Axial and coronal Ti weighted images were obtained with an ECG-gated technique. On

2

without

of Cuvier) that opens into the primitive sinus venosus. The anterior cardinal veins extend cephalad to the junctions of the internal jugular veins and subclavian veins on either side [2]. In an embryo with a crown-rump length of about 22 mm

A 54-year-old asymptomatic woman underwent MR imaging of the thorax because “buckling” of the aortic arch seen on a routine chest radiograph was suggestive of an aortic aneurysm. MR images (1 .5-T Magnetom 15H unit, Siemens, Iselin, NJ) were arch,

had no cardiovascular

appear as paired anterior and posterior cardinal veins that unite on each side to form a common cardinal vein (or duct

vein

by MR imaging.

at the level of the aortic

the patient

vein was made on the

Discussion

Case Report

obtained

Nozaki2

left brachiocephalic

alies, she was discharged

This is devein. This

left brachiocephalic

and Yoshimi

diagnosis of anomalous basis of these findings.

in 1 888 [1], but the MR characbeen described.

We report a case of an anomalous shown

Hayabuchi,1

Vein:

subclavian veins (Fig. 1 E). It passed downward to the right, inferior to the aortic arch, and entered the superior vena cava (Fig. 1 F). A

and subclavian

veins to the right brachiocephalic vein and the superior vena cava. It runs obliquely downward and to the right, passing superior and anterior to the aortic arch and anterior to the left subclavian,

(Innominate)

Kurume,

limb

become

the precardinal

trunk. trunk,

Fukuoka

Ray Society

left

brachiocephalic

When the anastomosis the left brachiocephalic

830, Japan.

Kurume, Fukuoka 830, Japan. Roentgen

the

anastomosis

Address

occurs

vein

anterior

occurs posterior vein runs posterior

reprint

requests

to K. Fujimoto.

[3].

to the to the to the

American Journal of Roentgenology 1992.159:479-480.

480

FWIMOTO

ET

AL.

AJR:159,

September

1992

Fig. 1.-Anomalous left brachiocephalic vein in a 54-year-old woman. A-D, Axial TI-weighted MR images (920/15) show signal void (arrows) passing downward and lateral to aortic arch (A) and crossing mediastinum to right (B), posterior to ascending aorta and anterior to trachea (C). It then enters superior vena cava (D). E and F, Coronal TI-weighted MR images show signal void (arrowheads) extending from confluence of left internal jugular vein (short arrow) and left eubclavlan vein (long arrow). ft passes downward to right, inferior to aortic arch (AD) and superior to left pulmonary artery (PA), and enters superior vena cava.

aorta after birth. It has been called the anomalous left brachiocephalic vein. As the left brachiocephalic vein ran inferior to the aortic arch and superior to the pulmonary artery in our case, it was suggested that the precardinal anastomosis might have been present posterior to the aortic trunk at the level between the third and the fourth branchial arch arteries, or at the sixth branchial arch artery, in the embryonic stage [3]. The anomalous left brachiocephalic vein was first described by Kerschner [1] in 1 888. The angiographic findings of this anomaly were first described by Roberts et al. [4] in 1951, echocardiographic findings by Cloez et al. [5] in 1 982, and CT findings by Webb et al. [6] in 1 982, but MR findings have not previously been reported. Although an anomalous left ascending

brachiocephalic

vein

may

be

adequately

shown

angiography, MR imaging has the advantage format, and neither contrast enhancement ionizing radiation is needed.

We conclude

that MR imaging

with

CT

or

of a multiplane nor the use of

clearly showed

the anoma-

bus left brachiocephalic vein. Because this anomaly may be shown with various types of medical imaging, radiologists should be aware that it is a possible finding.

REFERENCES 1 . Kerschner L. Zur Morphologie der Vena cava inferior. Anat Anz 1888;3:808-823 2. Gerlis L, Ho SY. Anomalous subaortic position of the brachiocephalic (innominate) vein: a review of published reports and report of three new cases. Br Heart J 1989;61 :540-545 3. Yoshida Y, Seki Y, Yasutaka S. A case of the left brachiocephalic vein passing behind the ascending aorta in man. Kaibogaku Zasshi 1984;59: 168-1 76 4. Roberts JR. Dotter CT, Steinberg I. Superior vena cava and innominate veins: angiographic study. AJR 1951;66:341-352 5. CIoez JL, Ravault F, Maroon F, Pemot C. Thonc veineux innomine en position sous-aortique: interet de I’echocardiographie de contraste par voie suprasteinale. Arch Mal Coeur Vaiss 1982;75:939-943 6. Webb WR, Gamsu G, Speckman JM, et al. Computed tomographic demonstration of mediastinal venous anomalies. AJR 1982;139: 157-1 61