OBJECTIVE: We analyzed intracranial regional blood flows using an
optical flow method (OFM) and digital subtraction angiography in patients with
internal carotid artery (ICA) stenosis. We also retrospectively explored the
correlation between the patients' diagnoses and the severity of the ICA
stenoses.
MATERIALS AND METHODS: OFM, an image-processing algorithm
to estimate motion, was applied to determine the mean velocity V
$_{mean}$
in the vessels. A group of 40 patients without vascular anomalies acted as the
control group. The patients were classified as having either moderate stenosis
(< 80%, n=14) or severe stenosis (> 80%, n=23).
RESULTS: The V
$_{mean}$
of the ICAs was significantly lower in the
stenotic group compared with the control group (p< 0.01). The V
$_{mean}$
of the ICAs was inversely correlated with the severity of the stenosis
(p< 0.05). The receiver operating characteristic curve of the V
$_{mean}$
in an AP view showed substantial discriminatory power, with an optimal
cutoff value of 3.48 pixels/frame for the detection of patients with carotid
stenosis. The sensitivity and specificity were 84% and 50%, respectively.
On a lateral view, the best cutoff for the V
$_{mean}$
was 4.01
pixels/frame, and the sensitivity and specificity were 92% and 43%,
respectively.
CONCLUSIONS: Digital subtraction angiography combined with the OFM is a feasible
parametric method for intracranial blood flow measurements in patients with moderate to severe carotid stenosis.
