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 (GREL 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 infiratentorial 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.