MR-IMAGING OF HEMORRHAGIC BRAIN-LESIONS - A COMPARISON OF DUAL-ECHO GRADIENT-ECHO 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 hemorrha gic 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 hemo rrhage underwent dual-echo GRASE (TEeff1/TEeff2, 35/85) and fast spin- echo (25/110) imaging. The techniques were matched for TR (3032 msec), spatial resolution, and acquisition time. Two neuroradiologists revie wed 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, diamagn etic susceptibility artifacts, chemical shift artifacts along the phas e- and frequency-encoding directions, and artifactual CSF hyperintensi ty in the thin curvilinear cortical sulci and the Virchow-Robin spaces on only the proton density-weighted images. RESULTS. The average numb er and conspicuity of dark (paramagnetic) lesions were significantly g reater on GRASE than on fast spin-echo images (p < .05 and p < .001, r espectively). We found no significant difference in the average number of bright lesions revealed by either technique (p > .1), Chemical shi ft artifacts along the phase-encoding directions were more prominent o n 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 visual ly apparent difference was found in the degree of diamagnetic suscepti bility artifacts seen with the two techniques. CONCLUSION. Dual-echo G RASE imaging can be helpful in the examination of patients with suspec ted acute brain hemorrhage.