Acute subarachnoid hemorrhage: MR imaging with fluid-attenuated inversion recovery pulse sequences.

TLDR

The study assessed whether fluid‑attenuated inversion recovery (FLAIR) MR imaging can detect acute subarachnoid hemorrhage. MR imaging with FLAIR sequences was performed on 20 SAH patients and 27 controls using a 0.5‑T scanner, with images acquired 2 h–2 days post‑ictus and compared to CT findings. FLAIR imaging consistently revealed high‑intensity SAH signals, especially in the posterior fossa where CT is limited, and a double‑blind comparison showed no misclassification between patients and controls, confirming FLAIR’s diagnostic reliability.

Abstract

PURPOSE: To evaluate the usefulness of fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) imaging sequences in the detection of acute subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: MR imaging with FLAIR sequences was performed with a 0.5-T superconducting unit in 20 patients (aged 30-72 years) with acute SAH due to a ruptured aneurysm and in 27 control subjects (aged 32-72 years). FLAIR images were obtained 2 hours to 2 days after ictus. Findings were evaluated and compared with computed tomographic (CT) findings. RESULTS: In all patients, acute SAH was clearly demonstrated as an area with signal intensity that was high relative to that of the normal cerebrospinal fluid and surrounding brain parenchyma at FLAIR imaging. This sequence was especially useful in demonstration of acute SAH in the posterior fossa, which was difficult to show at CT because of beam-hardening artifacts. In a double-blind comparison, no FLAIR images acquired in control subjects were confused with those acquired in control subjects were confused with those acquired in patients. CONCLUSION: FLAIR sequences reliably provide diagnostic images in patients with acute SAH.