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

Abstract

Purpose:To evaluate the diagnostic value of susceptibilityweighted imaging (SWI) for studying brain masses. Materials and Methods:SWI is a high-resolution, threedimensional, 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 ϭ 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%, 63%, and 75% of the data, respectively, in a subgroup of 38 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.

High-Resolution Contrast-Enhanced, Susceptibility-Weighted MR Imaging at 3T in Patients with Brain Tumors: Correlation with Positron-Emission Tomography and Histopathologic Findings

“…The contrast-enhancement behavior of all of the lesions in both sequences was also assessed and compared. In good agreement with Sehgal et al, 28 the contrast enhancement of brain lesions, visible in SW-MR images, was equal to that of T1-weighted SE sequences. In our study, 3 high-grade lesions, which demonstrated either minimal or no contrast enhancement, showed at least a low frequency of intralesional SusE.…”

“Brush Sign” on Susceptibility-Weighted MR Imaging Indicates the Severity of Moyamoya Disease

“…Uncoupling between oxygen supply and demand in hypoperfused tissue may cause a relative increase of deoxyhemoglobin levels and a decrease of oxyhemoglobin in the tissue capillaries and the draining veins. Therefore, SWI has been applied to various pathologies of the brain that affect magnetic inhomogeneity, such as stroke, 8,11 trauma, 8 cerebral cavernous malformation, 12,13 arteriovenous malformation, 14 dural arteriovenous fistula, 15 pathophysiology affecting iron storage conditions, [16][17][18] brain tumor, 19 and cerebral amyloid angiopathy. 20 It is noteworthy that this method has the potential to demonstrate increased oxygen extraction in focal cerebral ischemia.…”

Susceptibility-Weighted Imaging in the Diagnosis of Early Basal Ganglia Germinoma

“…It can be used to detect blood products and biologic metal accumulation and provides additional information in brain tumor evaluation, 16 which is valuable in BG germinoma due to its characteristic intratumoral hemorrhage. SWI acquired with a gradient recalled-echo sequence is more suitable than SWI with a spinecho sequence in evaluating tumor vascularity.…”

“…Second, it is possible that transferrin secreted by the tumor cells binds to transferrin receptors on neurons and glial cells, which are then transported into the globus pallidus. 16,19 Further histologic-radiologic correlation studies are needed to support the proposed mechanisms.…”