Detection of hemosiderin deposition by T2*-weighted MRI after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE Subarachnoid hemorrhage (SAH) is very difficult to diagnose several months after its onset. We thus investigated subarachnoid hemosiderin deposition well after SAH by T2*-weighted MRI, a sensitive method for hemosiderin detection. METHODS To investigate how hemosiderin deposition as confirmed by T2*-weighted MRI contributes to the determination of prior SAH and how the extent of hemosiderin deposition is associated with a number of clinical factors, we retrospectively analyzed 58 patients >3 months after SAH associated with ruptured aneurysms. We also investigated 209 healthy volunteers as controls. RESULTS T2*-weighted MRI demonstrated subarachnoid hemosiderin deposition in 72.4% of the SAH patients, whereas no deposition was seen in the healthy volunteer group. The hemosiderin was preferentially deposited in the subarachnoid space near a ruptured aneurysm. Odds ratios (ORs) were estimated from logistic regression analyses correlating hemosiderin deposition with other factors. Age (>or=54 years) (OR, 5.1; 95% CI, 1.03 to 25.0; P=0.046), Fisher grade 3 on initial CT (OR, 8.0; 95% CI, 1.26 to 50.4; P=0.027), and Karnofsky Scale score <or=80% 6 months after onset of SAH (OR, 12.8; 95% CI, 1.97 to 83.3; P=0.0077) were all found to be independently associated with hemosiderin deposition levels. CONCLUSIONS T2*-weighted MRI is an effective means of diagnosing prior SAH and may also reveal the location of a ruptured aneurysm. The extent of hemosiderin deposition was significantly associated with several factors, including age, CT findings, and poor prognosis.