Background: In patients with steno-occlusive disease, recent findings suggest that hemodynamic alterations may also be associated with crossed cerebellar diaschisis (CCD) rather than a functional disruption alone.
Purpose: To use a quantitative multiparametric hemodynamic MRI to gain a better understanding of hemodynamic changes related to CCD in patients with unilateral anterior circulation stroke.
Study type: Prospective cohort study.
Population: Twenty-four patients (25 datasets) with symptomatic unilateral anterior circulation stroke.
Field strength/sequence: 3T/two sequences: single-shot (echo-planar imaging) EPI sequence and T2* gradient echo perfusion-weighted imaging study.
Assessment: The presence of CCD was inferred from the cerebellar asymmetry index (CAI) of the blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) exam, which was calculated from the mean BOLD-CVR and standard deviation of the CAI of the healthy control group. For all perfusion-weighted (PW)-MRI parameters, the cerebellar and middle cerebral artery (MCA) territory asymmetry indices were calculated.
Statistical tests: Independent Student's t-test to compare the variables from the CCD positive(+) and CCD negative(-) groups and analysis of covariance (ANCOVA) to statistically control the effect of covariates (infarct volume and time since ischemia onset).
Results: CCD was present in 33% of patients. In the MCA territory of the affected hemisphere, BOLD-CVR was significantly more impaired in the CCD(+) group as compared to the CCD(-) group (mean BOLD-CVR ± SD [%BOLD signal/ΔmmHgCO2 ]: -0.03 ± 0.12 vs. 0.11 ± 0.13, P < 0.05). Moreover, the mean transit time (MTT) (asymmetry index (%) CCD(+) vs. CCD(-): 28 ± 23 vs. 4 ± 11, P < 0.05) and time to peak (TTP) (10 ± 10 vs. 2 ± 5, P < 0.05) in the MCA territory of the affected hemisphere were significantly prolonged, while cerebral blood volume was, on average, increased in the CCD(+) group (25 ± 15 vs. 4 ± 19, P < 0.05).
Data conclusion: Our findings show that, in patients with symptomatic unilateral anterior circulation stroke, CCD is associated with hemodynamic impairment in the ipsilateral MCA territory, which further supports the concept of a vascular component of CCD.
Level of evidence: 3 TECHNICAL EFFICACY STAGE: 3.
Keywords: BOLD-fMRI; MCA territory; cerebrovascular reactivity; crossed cerebellar diaschisis; hemodynamic; perfusion-weighted MRI.
© 2020 International Society for Magnetic Resonance in Medicine.