Ultrasonographically predicting the extent of collateral flow through superficial temporal artery-to-middle cerebral artery anastomosis.
OBJECTIVE
This study was performed to elucidate whether the extent of bypass flow through superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis could be indirectly estimated by measuring the blood flow velocity in the superficial temporal artery (STA) by using duplex ultrasonography.


METHODS
We analyzed 29 patients (31 sides) who underwent STA-MCA bypass surgery for occlusive cerebrovascular disease (28 sides) or unclippable cerebral aneurysm that required therapeutic occlusion of the internal carotid artery (three sides). The flow velocities of the STA were measured by using ultrasonography. For patients who underwent the surgery unilaterally, the flow velocity ratios of the operated side to the contralateral side for the individual arteries were calculated. The correlation between these flow velocity parameters and the extent of bypass flow, which was graded based on the findings of cerebral angiography, was investigated.


RESULTS
Both the affected STA flow velocity and the STA flow velocity ratio, particularly those in the end diastole, increased in patients with more extensive bypass flow. In patients with extensive, moderate, and poor bypass flow, the end diastolic flow velocities of the operated STA were 27.4 +/- 8.8, 23.0 +/- 7.8, and 13.5 +/- 7.5 cm/s, respectively and the end diastolic flow velocity ratios of the STA were 3.4 +/- 0.8, 2.1 +/- 0.5 and 1.3 +/- 0.4, respectively. The pulsatility index and resistance index of the affected STA were significantly lower in the patients with more extensive bypass flow. The optimal threshold value of the end diastolic flow velocity ratio of STA for the group with extensive bypass flow was 2.75, whereas that for the group with poor bypass flow was 1.60. With the obtained values, the sensitivity and specificity were 87.5% and 93.9% for the group with extensive bypass flow and 95.2% and 95.0% for the group with poor bypass flow, respectively.


CONCLUSIONS
The blood flow velocity in the operated STA seems to be a highly sensitive parameter for predicting the extent of bypass flow in patients undergoing STA-MCA anastomosis.
Department of Cerebrovascular Disease, Clinical Research Institute, National Kyushu Medical Center, Fukuoka, Japan.
Shuji
S
Arakawa
Masahiro
M
Kamouchi
Yasushi
Y
Okada
Kazuhiro
K
Kishikawa
Tsuyoshi
T
Omae
Tooru
T
Inoue
Setsuro
S
Ibayashi
Masatoshi
M
Fujishima
D015901:Angiography, Digital Subtraction; D001783:Blood Flow Velocity; D002342:Carotid Artery, External / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D002533:Cerebral Angiography; D002539:Cerebral Arterial Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D002548:Cerebral Revascularization; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013699:Temporal Arteries / Q000000981:diagnostic imaging; D018616:Ultrasonography, Doppler, Duplex