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. 2025 Sep 6:5:105603.
doi: 10.1016/j.bas.2025.105603. eCollection 2025.

Changes in hemorrhage pattern on consecutive non-contrast CT scans in non-aneurysmal subarachnoid hemorrhage patients

René van den Berg  1 , Wouter Dronkers  2 , Olvert Berkhemer  1 , Arian Karbe  3 , Menno Germans  3 , W Peter Vandertop  2   4 , Bart J Emmer  1 , Dagmar Verbaan  2   4
Affiliations

Changes in hemorrhage pattern on consecutive non-contrast CT scans in non-aneurysmal subarachnoid hemorrhage patients

René van den Berg et al. Brain Spine. .

Abstract

Introduction: The diagnosis perimesencephalic subarachnoid hemorrhage (PMSAH) is based on a specific distribution pattern within 72 h after ictus. However solid evidence is lacking for this time window with the potential risk that blood distribution can change over time, with implications for the management of these patients.

Research question: To study cisternal and intraventricular blood pattern changes on initial and follow-up non-contrast CT scans (NCCTs) during the first 72 h.

Materials and methods: This retrospective study included consecutive PMSAH and non-perimesencephalic (NPSAH) patients in whom at least two NCCTs were performed within the first 72 h. Presence and changes in the distribution of cisternal and intraventricular blood was independently assessed by three observers.

Results: 135 patients (62 PMSAH and 73 NPSAH) were included. The distribution of SAH remained unchanged within the first 72-h in 63 (47 %) patients (PMSAH: 38 (61 %), NPSAH: 25 (39 %))(p < 0.01). An increase in SAH distribution from 0 to 6 h was seen in 7/47 PMSAH (15 %) versus 24/47 (51 %) in NPSAH patients (p < 0.01). A decrease in SAH distribution from 0 to 6 h was seen in 6/47 (13 %) PMSAH patients versus 2/47 (4 %) NPSAH patients (p < 0.01). Between 6 and 24 h, a 72 % decrease (10/14) was only seen in NPSAH patients. The diagnosis PMSAH never changed to NPSAH or vice versa due to SAH redistribution.

Discussion and conclusion: Within the first 72 h after ictus, redistribution of cisternal and intraventricular blood is seen more often in NPSAH than in PMSAH patients but did not change the specific diagnosis.

Keywords: Non contrast CT; Perimesencephalic hemorrhage; Subarachnoid hemorrhage.

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Conflict of interest statement

The Author(s) declare(s) that there is no conflict of interest.

Figures

Fig. 1
Fig. 1
56-year-old female patient with non-aneurysmal perimesencephalic subarachnoid hemorrhage (PMSAH). On the initial non-contrast CT (NCCT) scan a significant amount of blood is seen in the suprasellar and ambient cistern (A), but absent intraventricular blood (B). On the repeat NCCT 34 h later, the amount of blood in the suprasellar cistern has decreased (C) with now presence of intraventricular blood (D).
See this image and copyright information in PMC

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