Susceptibility-weighted imaging to visualize blood products and improve tumor contrast in the study of brain masses

Purpose: To evaluate the diagnostic value of susceptibility weighted imaging (SWI) for studying brain masses. Materials and Methods: SWI is a high-resolution, three-dimensional, fully velocity-compensated gradient-echo sequence that uses both magnitude and phase data. Custom postprocessing is applied to enhance the contrast in the magnitude images between tissues with different susceptibilities. This sequence was applied to 44 patients (24 males and 20 females, 15-89 years old, mean age = 50.3 years) with brain masses, pre- and/or postcontrast, and compared with conventional sequences (T1, T1 postcontrast, T2, proton density (PD), fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) at 1.5T). Correlation with pathology was obtained in 12 cases. All images were reviewed independently by three radiologists. Results: In the evaluation of tumor visibility, boundary definition, blood products, venous vasculature, architecture, and edema, SWI gave better information than the standard T1-weighted postcontrast images in 11%, 14%, 71%, 73%, and 75% of the data, respectively, in a subgroup of patients. This demonstrates that the information presented by SWI is complementary in nature to that available from conventional methods. On the whole, SWI was much, more sensitive for showing blood products and venous vasculature. SWI showed a useful FLAIR-like contrast and complemented the information obtained by conventional T1 postcontrast sequences regarding the internal architecture of the lesions. Good pathologic correlations were found for blood products as predicted by SWI. Conclusion: SWI should prove useful for tumor characterization because of its ability to better highlight blood products and venous vasculature and reveal new internal architecture.