No clear relationship between circadian rhythm and cerebral perfusion parameters in pediatric and early adult populations.

Background: Recent literature suggests circadian rhythm influences cerebral perfusion parameters in adults experiencing an acute large vessel occlusion, but this has never been investigated in the pediatric and young adult populations.

Methods: We queried the United States RAPID Insights database (10/05/2018-09/29/2023) for unique patients between 2 and 25 years with computed tomography perfusion (CTP). Included scans had a minimum ischemic core volume (rCBF <30 %) of >0 cc and a Tmax volume of >0 cc. Intracerebral hemorrhage cases were excluded. Anterior circulation large vessel occlusion cases were segregated and reported separately. Imaging time was subdivided into three epochs: Night (23:00 h-06:59 h), Day (07:00 h-14:59 h), and Evening (15:00 h-22:59 h). Age was analyzed by pre-defined strata: 2-5, 6-11, 12-18, and 19-25 years. Perfusion parameters were stratified by age and time epochs. We used non-parametric testing for variables with non-normal distributions.

Results: We included 2415 CTP scans, with 307 identified as LVO. There were 637 patients 18 or younger, with 85 LVOs. In the overall cohort, LVOs had higher penumbral volumes (75.0 cc [25.0-156.0] vs 26.0 cc [8.0-78.0], p < 0.0001) and mismatch volumes (54.0 cc [18.0-120.0] vs 21.0 cc [7.0-62.0], p < 0.0001). In the LVO subgroup, there was a trend towards higher mismatch volumes at night (58.0 cc [IQR 19.5-139.8]) compared to evening (50.0 cc [IQR 18.8-114.3]) or daytime (55.0 cc [17.0-126.0]), but these differences were not significant (p = 0.72).

Conclusion: Contrary to reports in adults, we did not find a clear association between time of day and cerebral perfusion parameters among pediatric and young adult patients.