Acute subarachnoid haemorrhage: detection with magnetic resonance imaging.

The purpose of this study was the evaluation of fluid attenuated turbo inversion recovery (FLAT TIRE) MR pulse sequence for detecting acute subarachnoid hemorrhage (SAH). Seven patients with SAH were studied within 6 days of ictus. Six of them underwent both CT and MRI and one MRI only. Pulse sequences included T1 spin echo (SE), PD and T2 turbo spin echo (TSE) and FLAT TIRE (TR/TI/TE = 6500/1800/140-180). All studies were performed on a 0.5 T system (Gyroscan T5, Philips Medical Systems). Simulated acute SAH was also studied with MRI. The FLAT TIRE sequence was better than the SE and TSE in all seven cases and better than CT in two cases. In two cases MRI was equivalent to CT, and in another two MRI underestimated the extent of SAH. The simulated acute SAH could be detected easily with the FLAT TIRE sequence, with difficulty on the T1 weighted images and not at all on the PD/T2 weighted images. The specific FLAT TIRE sequence used seems promising for the detection of acute SAH.