RESUMEN
Objective To measure the sensitivity and specificity of gradient echo T*_2(GRE-T*_2) to subarachnoid haemorrhage (SAH). Methods 12 patients with SAH underwent MRI using T_1WI, T_2WI, FLAIR, GRE-T*_2 sequences and CT as well. Results (1)In the acute-stage of the patients, SAH was seen as an area of high signal intensity as compared with the surrounding cerebrospinal fluid in 66.6% of the cases on T_1-weighted images, and in 100% on FLAIR images; low signal intensities were seen in 50.0% of the cases on T_2-weighted images, and in 100% on GRE-T*_2-weighted images; (2) In the subacute of the patients, SAH was detected on T_1-weighted images (25.0% of cases), FLAIR (25.0%), T_2-weighted images (0), GRE-T*_2-weighted images (100.0%); (3) In the patients with atypical SAH, both CT and FLAIR sequence in MRI were negative for SAH, while lumber acupuncture and GRE-T*_2 had positive findings. Conclusion GRE-T*_2 is the most sensitive sequence of MRI for detecting acute and subacute SAH and has significant advantages over CT in the detection of subacute and atypical SAH.