Detection of Hemorrhagic Hypointense Foci in the Brain on Susceptibility-Weighted Imaging Clinical and Phantom Studies

RATIONALE AND OBJECTIVES: To determine the sensitivity of susceptibility-weighted imaging (SWI) for depicting hemorrhagic hypointense foci of the brain in comparison with gradient-recalled echo (GRE)- and GRE-type single-shot echo-planar imaging (GREI, GRE-EPI), and to assess the basic characteristics of the susceptibility effect by using a phantom. MATERIALS AND METHODS: We prospectively examined 16 patients (9 males, 7 females, aged 10-74 years, mean 43 years) with hypointense foci using SWI, GREI, and GRE-EPI at a 1.5-T magnetic resonance (MR) unit. The contrast-to-noise ratio (CNR), sensitivity to small hypointese foci, and artifacts were evaluated. To assess the basic characteristics of SWI, we performed a phantom study using different concentrations of superparamagnetic iron oxide (SPIO). RESULTS: The CNR of lesions was significantly greater for SWI than the other images (P < .0001). SWI detected the greatest number of small hypointense foci, even in the near-skull-base and infratentorial regions. Quantitative and qualitative analyses in our clinical and phantom studies demonstrated that the degree of artifacts was similar with SWI and GREI. CONCLUSION: SWI was best for detecting small hemorrhagic hypointense foci. Artifacts of SWI were similar to GREI.