Pseudoocclusion

of a Superficial

Downloaded from www.ajronline.org by 110.36.46.83 on 11/08/15 from IP address 110.36.46.83. Copyright ARRS. For personal use only; all rights reserved

ARTHUR

B.

Temporal-Middle

DUBLIN’

AND

C.

However,

since this seemed

paresis

of the

hemisphere

A superficial

upper

extremity.

complete artery. with

No carotid

extracranial cross-perfusion

via the left carotid

temporal-middle

graft.

The patient

recurrent

December

‘Department reprint

requeststoA.

Am J Roentgenol © 1978 American

6. 1977;

of Diagnostic

in view of the postoperative

has done well 2 months

neurologic

deficits

after surgery.

without

or symptoms.

Discussion

cerebral

The

bruits

CT an-

occlusion of the of the right

circulation artery

(fig. 1). end-to-side

accepted

Radiology.

after

revision

University

March of

California,

primary

value

of superficial

temporal-middle

cer-

ebral artery bypass grafts is prophylactic, preventing the progression of existing neurologic defects and the development of new ones [1, 3. 4]. Thus it is certainly appropriate to evaluate the postoperative patency of these grafts [2]. While Doppler evaluation of bypass patency has been used, the definitive study remains cerebral angiography [1]. Initially, some postoperative narrowing or spasm of

by-

pass was performed without complication. Two weeks after surgery, repeat angiography (with the catheter tip in the main

Received

occlu2A).

Report

by auscultation. Pre- and postcontrast Bilateral transfemoral carotid cerebral

giography demonstrated right internal carotid

cerebral

left

unlikely

(fig.

improvement, the catheter was withdrawn into the right common carotid artery, and a second injection was performed (fig. 2B). This study demonstrated excellent flow through the bypass

white male was admitted for evaluation of two recent episodes of left extremity paresis associated with right amaurosis ftigax. The neurologic examination revealed a mild residual

Bypass

carotid artery) demonstrated on the first series of films

A 62-year-old

were demonstrated scans were normal.

Artery

RICHEY’

trunk of the right external sion of the anastomosis

Microsurgical bypass procedures have gained increasing acceptance in cases of inoperable cerebnI vascular occlusive disease [1]. Postoperative cerebral angiography is frequently performed for the evaluation of shunt patency [2].The clinical and radiographic findings of the first reported case of pseudoocclusion of a superficial temporal-middle cerebral artery bypass are reported. Case

DUANE

Cerebral

the

anastomosis

may

be present

angiographically.

At our

6. 1978. Davis,

School

of

Medicine,

4301

X Street,

Sacramento,

California

95817.

Address

B. Dublin. 131:162-163, July 1978 Roentgen Ray Society

162

0361 -803X/78/0700

-

01 62 $00.00

Downloaded from www.ajronline.org by 110.36.46.83 on 11/08/15 from IP address 110.36.46.83. Copyright ARRS. For personal use only; all rights reserved

CASE

Fig.

2.-A,

Right

external

carotid

arteriogram, lateral (arrow). B, (arrow).

temporal-middle cerebral artery anastomosis excellent patency of graft on repeat injection

view, Right

163

REPORTS

6 sec common

institution, it has been shown that this spasm usually subsides 1-2 weeks after surgery. The great majority of grafts preserve their patency (up to a 20 month average follow-up in one series) [1]. We hypothesize that the simulated occlusion of the bypass in our patient on the initial series of films may have been related to two factors: (1) the excellent perfusion of the affected cerebral hemisphere from contralateral sources, and (2) spasm of the external cerebral artery. Thus the iodinated contrast material may have been rapidly diluted at the site of the anastomosis by nonopacified blood from the contralateral hemisphere. This dilution could have been enhanced by decreased contrast flow due to catheter-induced spasm of the external carotid artery. Withdrawal of the catheter to the common carotid artery improved contrast flow, which then overcame the dilution factor of nonopacified blood. In summary, any bypass graft occlusion must be viewed with suspicion. In high grade or complete internal carotid arterial stenotic lesions, selective injection of the

after

injection.

carotid

external carotid

showing

arteriogram.

carotid studies

Prolonged

filming

lack lateral

of opacification view,

circulation will help sequences

2 sec

distal after

to superficial

injection.

showing

is unnecessary, and common to prevent spasm artifacts. may

also

demonstrate

de-

layed flow through anastomosis. At our institution, angiography is delayed until 2 weeks after surgery to avoid additional artifacts caused by postsurgical spasm. REFERENCES Chater N, Papp J: Microsurgical vascular bypass for occlusive cerebrovascular disease: review of 100 cases. Surg Neurol 6:115-118, 1976 2. Anderson RE, Reichman OH, Davis DO: Radiological evaluation of temporal artery middle cerebral artery anastomosis.Radiology 113:73-79, 1974 3. Heilbrun MP, Reichman OH, Anderson RE, Roberts TS: Regional cerebral blood flow studies following superficial temporal-middle cerebral artery anastomosis. J Neurosurg 43:706-716, 1975 1

4.

.

Spetzler Physiological

A, Chater studies.

N: Microvascular J Neurosurg

bypass 45 : 508-51

surgery. 3. 1976

II.