MR imaging of hemorrhagic brain lesions: A comparison of dual-echo gradient- and spin-echo and fast spin-echo techniques

OBJECTIVE. Our objective was to assess the usefulness of the dual-echo gradient- and spin-echo (GRASE) technique in revealing acute hemorrhagic brain lesions and compare GRASE and fast spin-echo techniques for revealing acute hemorrhagic lesions and image artifacts. MATERIALS AND METHODS. Thirty- two consecutive patients with acute intracranial hemorrhage underwent dual- echo GRASE (TE(eff1)/TE(eff2), 35/85) and fast spin-echo (25/110) imaging. The techniques were matched for TR (3032 msec), spatial resolution, and acquisition time. Two neuroradiologists reviewed the images independently, documenting the number, size (<1, >1, or 1 cm in diameter), location, and signal characteristics (hypointense versus hyperintense compared with brain)of detectable lesions. These observers also compared matched T2- and proton density-weighted GRASE and fast spin-echo images for paramagnetic lesion conspicuity, diamagnetic susceptibility artifacts, chemical shift artifacts along the phase- and frequency-encoding directions, and artifactual CSF hyperintensity in the thin curvilinear cortical sulci and the Virchow- Robin spaces on only the proton density-weighted images. RESULTS. The average number and conspicuity of dark (paramagnetic) lesions were significantly greater on GRASE than on fast spin-echo images (p < .05 and p < .001, respectively). We found no significant difference in the average number of bright lesions revealed by either technique (p >. 1). Chemical shift artifacts along the phase-encoding directions were more prominent on GRASE than on fast spin-echo imaging. Chemical shift artifacts along the frequency- encoding directions and artifactual CSF hyperintensity were more prominent on fast spin-echo than on GRASE imaging. No visually apparent difference was found in the degree of diamagnetic susceptibility artifacts seen with the two techniques. CONCLUSION. Dual-echo GRASE imaging can be helpful in the examination of patients with suspected acute brain hemorrhage.