CT angiographic source images: flow- or volume-weighted?
OBJECTIVE
CTA-SI have been previously reported to correlate with CBV. We hypothesized that CTA-SI performed by modern multisection CT scanners are CBF-, not CBV-weighted.


METHODS
Sixty-four consecutive patients with anterior circulation stroke symptoms were selected from a stroke data base between June 2007 and January 2009. Two independent blinded readers calculated defect volumes of CTA-SI and PCCT, CBF, and CBV images. Spearman correlation of lesion volumes was performed. Linear regression and residual analysis demonstrated factors associated with outliers for CTA or PCCT for CBF and CBV volumes.


RESULTS
We found a strong positive correlation between CTA with CBF (r = 0.89, P < .0001) and between PCCT and CBV (r = 0.79, P < .0001). CTA to CBV (r = 0.5, P < .0001) and PCCT to CBF (r = 0.52, P < .0001) correlations were weaker. Positive CTA outliers had lower ASPECTS (P = .01), larger baseline CTA (149 ± 46 cm(3) versus 83 ± 32 cm(3); P = .002, respectively), and final infarct (190 ± 100 cm(3) versus 80 ± 50 cm(3); P = .09, respectively) volumes than nonoutliers. No baseline features were significantly related to PCCT outliers. There was no difference in the vessel occlusion sites for positive or negative outliers for CTA or PCCT (P = .55 and P = 1.00, respectively).


CONCLUSIONS
Our results indicate that CTA-SI are CBF- rather than CBV-weighted.
Department of Medical Imaging, University of Toronto, Sunnybrook Health Sciences Centre, Ontario, Canada.
M
M
Sharma
A J
AJ
Fox
S
S
Symons
A
A
Jairath
R I
RI
Aviv
D001810:Blood Volume / Q000502:physiology*; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D016208:Databases, Factual; D006801:Humans; D020243:Infarction, Anterior Cerebral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016014:Linear Models; D014057:Tomography, X-Ray Computed / Q000379:methods*