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 (greater than or equal to54 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 less than or equal to 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.