J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 17, Number 10, October 2025, pages 556-564

Optimal Timing of Post-Alteplase Brain Computed Tomography: Routine Twenty-Four-Hour Versus Extended Forty-Eight-Hour for Detecting Asymptomatic Intracranial Hemorrhage

Figure 1. Conceptual illustration of post-alteplase outcomes and transitions adapted from a multi-state (illness-death) model. ICH: intracranial hemorrhage; asICH: asymptomatic intracranial hemorrhage; sICH: symptomatic intracranial hemorrhage.

Figure 2. Study flow diagram. Numbers are provided only for groups identified after the first follow-up brain CT scan; subsequent counts are omitted because outcomes evolved dynamically over time and were analyzed using a multi-state (illness-death) model. IV: intravenous; ED: emergency department; MT: mechanical thrombectomy; TOAST: Trial of Org 10172 in Acute Stroke Treatment; CT: computed tomography; ICH: intracranial hemorrhage; asICH: asymptomatic intracranial hemorrhage; sICH: symptomatic intracranial hemorrhage.

Figure 3. Cumulative incidence of intracranial hemorrhage (ICH) over time following intravenous alteplase administration.

**Table 1.** Baseline Characteristics by Final Transitioned Outcomes at 7-Day Follow-Up
Baseline characteristics	sICH (n = 49)	asICH (n = 51)	no ICH (n = 455)	P value
Numbers in each group represent the final transitioned outcomes at the end of the 7-day follow-up. These differ from those in the study flow diagram, which reflect initial outcomes after the first follow-up brain CT scan. sICH: symptomatic intracranial hemorrhage; asICH: asymptomatic intracranial hemorrhage; ICH: intracranial hemorrhage; SD: standard deviation; NIHSS: National Institutes of Health Stroke Scale; IQR: interquartile range; CT: computed tomography.
Male, n (%)	22 (44.9)	30 (56.6)	252 (55.6)	0.225
Age (years), mean ± SD	69.7 ± 9.9	64.4 ± 10.1	64.5 ± 12.7	0.416
Body weight (kg), mean ± SD	57.5 ± 12.1	60.9 ± 13.9	58.3 ± 12.8	0.809
Initial NIHSS, median (IQR)	13 (10, 18)	12 (8, 17)	10 (7, 13)	< 0.001
Number of brain CT scans during admission, median (min, max)	2 (1, 6)	1 (1, 3)	1 (1, 4)	< 0.001
Dead during admission, n (%)
Neurological cause	15 (30.6)	0 (0)	8 (1.8)	0.006
Non-neurological cause	0 (0)	1 (1.9)	7 (1.5)

Table 1. Baseline Characteristics by Final Transitioned Outcomes at 7-Day Follow-Up

Baseline characteristics

sICH (n = 49)

asICH (n = 51)

no ICH (n = 455)

P value

Numbers in each group represent the final transitioned outcomes at the end of the 7-day follow-up. These differ from those in the study flow diagram, which reflect initial outcomes after the first follow-up brain CT scan. sICH: symptomatic intracranial hemorrhage; asICH: asymptomatic intracranial hemorrhage; ICH: intracranial hemorrhage; SD: standard deviation; NIHSS: National Institutes of Health Stroke Scale; IQR: interquartile range; CT: computed tomography.

Male, n (%)

22 (44.9)

30 (56.6)

252 (55.6)

0.225

Age (years), mean ± SD

69.7 ± 9.9

64.4 ± 10.1

64.5 ± 12.7

0.416

Body weight (kg), mean ± SD

57.5 ± 12.1

60.9 ± 13.9

58.3 ± 12.8

0.809

Initial NIHSS, median (IQR)

13 (10, 18)

12 (8, 17)

10 (7, 13)

< 0.001

Number of brain CT scans during admission, median (min, max)

2 (1, 6)

1 (1, 3)

1 (1, 4)

< 0.001

Dead during admission, n (%)

Neurological cause

15 (30.6)

0 (0)

8 (1.8)

0.006

Non-neurological cause

0 (0)

1 (1.9)

7 (1.5)

**Table 2.** Frequency of Brain CT Scans for Asymptomatic Intracranial Hemorrhage Within 7 Days
Follow-up brain CT scans and timing of first detection	Asymptomatic ICH (n = 51)
Data represent patients whose final transitioned outcome was classified as asymptomatic intracranial hemorrhage (asICH) at the end of the 7-day follow-up. CT: computed tomography; ICH: intracranial hemorrhage; SD: standard deviation.
Number of brain CT scans performed
1-time CT patients, n (%)	37 (69.8)
2-time CT patients, n (%)	11 (20.8)
3-time CT patients, n (%)	5 (9.4)
Time to first detection (h), mean ± SD	25.7 ± 8.7

Table 2. Frequency of Brain CT Scans for Asymptomatic Intracranial Hemorrhage Within 7 Days

Follow-up brain CT scans and timing of first detection

Asymptomatic ICH (n = 51)

Data represent patients whose final transitioned outcome was classified as asymptomatic intracranial hemorrhage (asICH) at the end of the 7-day follow-up. CT: computed tomography; ICH: intracranial hemorrhage; SD: standard deviation.

Number of brain CT scans performed

1-time CT patients, n (%)

37 (69.8)

2-time CT patients, n (%)

11 (20.8)

3-time CT patients, n (%)

5 (9.4)

Time to first detection (h), mean ± SD

25.7 ± 8.7

**Table 3.** Comparison of First Asymptomatic Intracranial Hemorrhage (asICH) Detection Between 24-Hour Routine and 48-Hour Extended Brain Computed Tomography Scenarios
	First transition to asymptomatic intracranial hemorrhage (asICH) (n = 63^a)
^aN = 63 represents the first detection of asymptomatic intracranial hemorrhage (asICH), which differs from the final transitioned outcome (n = 51), as 12 patients progressed to symptomatic intracranial hemorrhage (sICH) within 7 days. CT: computed tomography.
First asICH detection, n (%) - sensitivity	19 (30.2)	61 (96.8)	< 0.001

Table 3. Comparison of First Asymptomatic Intracranial Hemorrhage (asICH) Detection Between 24-Hour Routine and 48-Hour Extended Brain Computed Tomography Scenarios

First transition to asymptomatic intracranial hemorrhage (asICH) (n = 63^a)

CT timing scenario 24-h routine

CT timing scenario 48-h extended

P value

^aN = 63 represents the first detection of asymptomatic intracranial hemorrhage (asICH), which differs from the final transitioned outcome (n = 51), as 12 patients progressed to symptomatic intracranial hemorrhage (sICH) within 7 days. CT: computed tomography.

First asICH detection, n (%) - sensitivity

19 (30.2)

61 (96.8)

< 0.001