====== Maximum systolic velocity ======

[[Peak systolic velocity]]


[[Internal carotid artery]] [[hemodynamics]] ([[maximum systolic velocity]] and average velocity [Vmax , Vavg ], average blood flow [Flowavg ], and wall shear stress) were analyzed based on [[4D flow MRI]] data. [[Cerebral infarction]], defined as the occurrence of events, in 124 brain hemispheres was determined according to clinical symptoms and conventional [[Brain magnetic resonance imaging]].

Statistical tests: The independent-sample [[T-test]] was used to evaluate differences in [[Internal carotid artery]] [[hemodynamics]] between infarcted and non-infarcted [[hemisphere]]s. [[Binary logistic regression]] was performed to investigate the relationship between ICA hemodynamics and events. A P value < 0.05 was considered statistically significant.

Results: Sixty-one infarcted hemispheres (eight hemispheres with acute ischemic damage, 30 with chronic ischemic damage, and 23 with chronic hemorrhagic damage) had [[cerebrovascular event]]s and 63 non-infarcted hemispheres did not. The hemodynamic parameters in the infarcted hemispheres (Vmax : P < 0.001; Vavg : P = 0.003; and Flowavg : P = 0.004) were significantly lower than those in the non-infarcted hemispheres. However, Vmax (P = 0.052), Vavg (P = 0.107), and Flowavg (P = 0.074) were not significantly different among hemispheres with acute ischemic lesions, chronic ischemic lesions and chronic hemorrhagic lesions. Vmax (odds ratio 3.033, 95% CI: 1.075-8.562) was independently associated with cerebrovascular events.

Data conclusion: Vmax may be a higher risk factor for cerebrovascular events in MMA patients.

[[Evidence level]]: 2 TECHNICAL EFFICACY STAGE: 3
((Wang M, Yang Y, Zhang W, Zhou F, Zhang X, Zhang J, Zhang B. [[Risk Factor]]s for [[Cerebrovascular]] [[Event]]s in [[Moyamoya]] [[Angiopathy]] Using [[4D Flow MRI]]: A Pilot Study. J Magn Reson Imaging. 2022 Nov 9. doi: 10.1002/jmri.28522. Epub ahead of print. PMID: 36349829.))