Related Experiment Video
Updated: Aug 13, 2026
A Volumetric Method for Quantification of Cerebral Vasospasm in a Murine Model of Subarachnoid Hemorrhage
Published on: July 28, 2018
Nationwide diurnal pattern among intracerebral hemorrhage incidence and volume
Anirudh Sreekrishnan1, Ronda Lun1, Gregory W Albers1
1Department of Neurology, Stanford Hospital, Palo Alto, CA, United States.
Insights
Intracerebral hemorrhage (ICH) volumes are larger when they occur at night. This study validates diurnal trends in ICH incidence and hematoma volume using a large dataset of automated brain scans.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Intracerebral hemorrhage (ICH) exhibits seasonal and diurnal patterns.
- Severity of ICH may be greater during nighttime hemorrhages.
- Rhythmicity in coagulation, blood pressure, and sleep-wake cycles may influence ICH.
Purpose of the Study:
- Validate diurnal trends of ICH incidence in a large nationwide database.
- Evaluate differences in hematoma volume based on image acquisition time.
Main Methods:
- Utilized serial non-contrast head CT (NCHCT) data from U.S. hospitals (2020-2021).
- Employed automated imaging software (iSchemaView) for ICH detection.
- Excluded patients aged ≤25, hematoma volume ≥100 ml, or ≤0.4 ml.
- Categorized imaging times into Night (23:00-06:59), Day (07:00-14:59), and Evening (15:00-22:59).
Main Results:
- Included 19,397 scans with a median ICH volume of 2.9 ml.
- Peak imaging occurred around noon.
- Hematoma volume significantly differed across timepoints (p=0.003).
- Nighttime ICHs (avg. 14.2 ml) were larger than daytime (12.9 ml) or evening (13.0 ml) ICHs.
Conclusions:
- Confirmed diurnal trends in ICH incidence in a real-world, multi-site dataset.
- Detected subtle differences in ICH volume based on time of imaging.
- Further research is needed to understand the underlying mechanisms.
Introduction:
Intracerebral hemorrhage (ICH) incidence follows both seasonal and diurnal patterns with greater severity reported in nighttime hemorrhages. These differences have been attributed to variations in the coagulation cascade, blood pressure, and sleep-wake cycle that all have their own rhythmicity. The purpose of this analysis was to validate these trends in a large nationwide database of automated ICH detection scans and evaluate for differences in hematoma volume by image acquisition time.
Methods:
Serial non-contrast head CT (NCHCT) data, processed with an automated imaging software (iSchemaView), was acquired from U.S. hospitals between 1/1/2020 and 12/31/2021. Final exclusion criteria included: (1) patient age ≤ 25, (2) hematoma volume ≥ 100 ml, (3) hematoma volume ≤ 0.4 ml. Imaging time was subdivided into three epochs: (1) Night: 23:00h-06:59h, (2) Day: 07:00h-14:59h, and (3) Evening: 15:00h-22:59h.
Results:
A total of 19,397 scans were included in the final analysis with a median ICH volume of 2.9 ml and mean volume of 13.23 mL; 15.6% of scans had volumes above 30 ml. Peak imaging occurred around noon. Hematoma volume was significantly different across timepoints (p = 0.003), with ICHs presenting at night (average volume 14.2 ml) larger than those presenting during the day (12.9 ml, p = 0.002) or evening (13.0 ml, p = 0.012).
Conclusion:
In this real world, multi-site data set, we show similar diurnal trends in ICH incidence as previously reported and detected subtle differences in volume based on time of imaging. Further research is required to elucidate the potential underlying mechanisms for these differences.
Related Concept Videos
01:17Hemorrhagic Stroke l: Introduction
01:29Hemorrhagic Stroke ll: Pathophysiology
01:14Increased Intracranial Pressure l: Introduction
01:29Increased Intracranial Pressure ll: Pathophysiology
01:19Cerebral Edema l: Introduction
01:22Cerebral Edema ll: Pathophysiology