Usefulness of Contrast-Enhanced T1-Weighted Sampling Perfection with Application-Optimized Contrasts by Using Different Flip Angle Evolutions in Detection of Small Brain Metastasis at 3T MR Imaging: Comparison with Magnetization-Prepared Rapid Acquisition of Gradient Echo Imaging

Definition of the regions of interest. A, Contrast-enhanced sagittal SPACE image. B, Contrast-enhanced sagittal MPRAGE image. A circular or oval region of interest for a lesion is as large as possible, excluding lesion edges, to avoid a partial volume effect (solid oval), and the region of interest for the background is on the brain parenchyma near the lesion in the same plane (dotted circle). We defined these regions of interest carefully to avoid CSF or vessels. The size and shape of the region of interest on the brain parenchyma are identical on both SPACE and MPRAGE images.

Results of the ROC analyses. In both observer groups, the Az was significantly higher for SPACE than for MPRAGE. The difference in Az values between the 2 observer groups was smaller for SPACE images. The asterisk in A indicates residents, P = .0001; the dagger in B, neuroradiologists, P = .0013.