Validation of computed tomographic middle cerebral artery "dot"sign: an angiographic correlation study.
OBJECTIVE
The middle cerebral artery (MCA) "dot" sign consists of hyperdensity of an arterial structure, seen as a dot in the sylvian fissure. The MCA dot sign has been proposed to indicate thrombosis of M2 or M3 MCA branches, analogous to the hyperdense middle cerebral artery (HMCA) sign indicating M1 thrombosis. The MCA dot sign has not been validated previously against the gold standard of conventional cerebral angiography.


METHODS
Noncontrast CT scans and immediately subsequent cerebral angiograms from 54 acute stroke patients within 8 hours of symptom onset were analyzed. CT films were inspected for the MCA dot sign and HMCA sign. Vascular findings on CT were compared with findings at angiography.


RESULTS
Mean patient age was 71 years; median National Institutes of Health Stroke Scale score was 16.5. Mean time from symptom onset to CT was 125 minutes, and that from CT to angiography was 117 minutes. All patients had arterial occlusion at angiography. Of the anterior circulation occlusions, M1 occlusions were noted in 28 patients, isolated M2 in 15, and isolated M3 in 4. One definite MCA dot sign was observed in 16.7% of patients, and an HMCA sign was observed in 13.9%. MCA dot sign performance in predicting the presence of M2 or M3 clot at angiography was as follows: sensitivity 38%, specificity 100%, positive predictive value 100%, negative predictive value 68%, and overall accuracy 73%.


CONCLUSIONS
The MCA dot sign is a highly specific and moderately sensitive indicator of acute thrombus in the M2/M3 MCA branches, as validated by catheter angiography. The MCA dot sign is a useful additional acute stroke CT marker.
Department of Neurology, Division of Stroke and Cerebrovascular Disease, Palmer 125, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Boston, Mass 02215, USA. mleary@bidmc.harvard.edu
Megan C
MC
Leary
Chelsea S
CS
Kidwell
J Pablo
JP
Villablanca
Sidney
S
Starkman
Reza
R
Jahan
Gary R
GR
Duckwiler
Y Pierre
YP
Gobin
Steven
S
Sykes
Kristi J
KJ
Gough
Katrina
K
Ferguson
Jennifer N
JN
Llanes
Rinat
R
Masamed
Margaret
M
Tremwel
Bruce
B
Ovbiagele
Paul M
PM
Vespa
Fernando
F
Vinuela
Jeffrey L
JL
Saver
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography; D015331:Cohort Studies; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging*; D020767:Intracranial Thrombosis / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011379:Prognosis; D015641:Radiography, Interventional; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000592:standards*