Evolution of MRI changes on follow-up imaging at specific time intervalsa
| ≤90 Days | 91–365 Days | >365 Days | |
|---|---|---|---|
| No. | 28 | 24 | 23 |
| Time to follow-up MRI (day) | Median, 46 (range, 12–90) | Median, 159.5 (range, 92–365) | Median, 1136 (range, 382-3022) |
| Follow-up MRI demonstrated rebleed (No.) | 5 | 3 | 6 |
| T1 hyperintensity | 17/23 (73.9%) | 12/21 (57.1%) | 8/16 (50%) |
| T1 hyperintensity (moderate to significant) | 9/17 (52.9%) | 6/12 (50%) | 1/8 (12.5%) |
| Enhancement with gadolinium | 6/22 (27.3%) | 7/20 (35%) | 9/16 (56.2%) |
| Degree of enhancement (moderate to significant) | 2/6 (33.3%) | 1/7 (14.3%) | 2/9 (22.2%) |
| Edema | 2/23 (8.7%) | 0 | 0 |
| Degree of edema (moderate to significant) | 1/2 (50%) | – | – |
| DWI low intensity | 13/23 (56.5%) | 12/17 (70.1%) | 13/16 (81.2%) |
| ADC low intensity | 14/19 (73.7%) | 12/16 (75.0%) | 8/13 (61.5%) |
| Change to Zabramski type II or III lesion | 15/23 (65.2%) | 17/21 (80.9%) | 16/16 (100%) |
| Average size change (compared with original MRI) (mm) | Median, 1.4 (range, −6.5 to +1.7) | Median, 2.05 (range, −24.7 to +1.1) | Median, −3.3 (range, −9.7 to +8.9) |
Note:—– indicates no data.
↵a Denominators noted are based on the availability of the particular MRI sequence.