Affiliations: Department of Biomedical Imaging and Radiological
Science, China Medical University, Taichung City, Taiwan | Department of Biomedical Imaging and Radiological
Sciences, National Yang-Ming University, Taipei, Taiwan | Radiology Department, Taipei Veterans General
Hospital, Taipei, Taiwan | School of Medicine, National Yang-Ming University,
Taipei, Taiwan | Graduate Institute of Cancer Biology, China Medical
University, Taichung City, Taiwan
Abstract: 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.
