MR angiography of intracranial aneurysms: A comparison of 0.5 T and 1.5 T

The objective of this paper is to compare the diagnostic efficacy of 3 DFT time-of-flight MR angiography (MRA) at middle-field-strength and high-field-strength in diagnosis of intracranial aneurysms. Thirty-one patients, including 26 patients with angiographically confirmed intracranial aneurysms (n=28), underwent MRA at 0.5 and 1.5 T, Images were interpreted by six trained observers who were blinded to diagnosis, Twelve projections of MRA of the circle of Willis, by maximum-intensity projection algorithm, were reviewed using continuous confidence-judgment scales. It was found that MRA at 1.5 T was more sensitive than that at 0.5 T in detection of aneurysms, The sensitivity of six observers ranged between 50 and 64% (mean 56%) at 0.5 T, and between 61 and 86% (mean 75%) at 1.5 T, In the smaller aneurysms less than 5 mm, the differences between the units became greater, The sensitivity for small aneurysms ranged from 23 to 54% (mean 32%) at 0.5 T, and from 31 to 69% (mean 58%) at 1.5 T. Our conclusion was that high field strength confers higher accuracy in the detection of intracranial aneurysms with MRA with current-generation MR imagers. (C) 1997 Elsevier Science Ltd.