Cerebral Blood Flow Assessment by Digital Subtraction Angiography.
Digital subtraction angiography is the preferred technique in immediate assessment of blood flow for patients with cerebral vascular diseases during neurovascular intervention. However, assessment of vascular status in a given patient currently depends on the physicians’ intuitive judgment of dynamic contrast
agent distribution patterns observed with DSA.
Current DSA technology does not display volumetric blood flow rates. Flow in major cerebral blood vessels can be measured with other non-invasive imaging modalities including quantitative magnetic resonance angiography, Xenon-enhanced cerebral tomography, singlephoton emission computed tomography,9,10 or transcranial Doppler sonography.
Moreover, perfusion studies in computed tomography, magnetic resonance imaging and positron emission tomography enable clinical measurements of microcirculation. However, these advanced imaging modalities are not available during surgery due to space requirements of the scanners.
Some procedures are further limited by acceptable radiation dosage and unavailability of these techniques in smaller hospitals. Some studies have also cast doubt on perfusion methods for identifying infarct regions, because they involve image interpretation with respect to arbitrary mismatch thresholds.
Recently, increased acquisition rate in combination with de convolution analysis are beginning to provide metrics of cerebral blood flow, cerebral blood volume and mean transit time using DSA with dual panel detectors. Especially, absolute blood flow quantification in large vessels would be significant to improve the diagnostic capability of DSA.
Radiol Open J. 2016; 1(1): 21-30. doi: 10.17140/ROJ-1-104