Noninvasive Measurement of Cerebral Blood Flow With ^99m Tc-Hexamethylpropyleneamine Oxime Single-Photon Emission Computed Tomography and 1-Point Venous Blood Sampling

Abstract

Background and Purpose-The arterial and venous blood concentration of technetium 99m-labeled hexamethylpropyleneamine oxime (

Effect of cilnidipine vs losartan on cerebral blood flow in hypertensive patients with a history of ischemic stroke: a randomized controlled trial

“…Venous blood was sampled 5 min after injection to measure the blood radioactivity at steady state. We quantified the global CBF based on the following formula of a previous study (22): where Radioactivity is the whole brain radioactivity measured by SPECT, E is the first extraction fraction rate by the brain (0.72) (23), R is the retained fraction of lipophilic radioactivity in the brain (0.54) (23), CaL is the lipophilic tracer radioactivity in the arterial blood flow, Cv(5) is the radioactivity of the venous blood at steady state (5 min) and k is the slope of the regression line of (4.62).…”

“…Previous small‐scale studies in patients with a history of stroke reported that global CBF increases by 7.1% (SD 11.1%) with 4‐week losartan treatment and by 2.7% (SD 14.0%) with 4‐week cilnidipine treatment (11, 20). The coefficient of variation for global CBF measurement adopted in this study was reported as 8.6% (22). Assuming similar global CBF changes in the two treatment groups, we determined the non‐inferiority margin as −8.6%.…”