Department of Diagnostic and Therapeutic Radiology,
Faculty of Medicine, Tamathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
Pathology Unit, Faculty of Science, Rangsit University, Pathumthani 12000, Thailand
Objective: To evaluate the MR imaging features of pathologically diagnosed high and low flow vascular malformations.
Materials and methods: The MR images and pathological diagnosis of soft tissue vascular malformations between January 2008 and July 2013 were retrospectively review. The radiologist recorded the MRI appearances, including the flow void artifact, hypersignal intensity on T1W GRE images, phlebolith, and arterial enhancement on contrast-enhanced MRA images that aided in classifying the flow types. The musculoskeletal pathologist re-evaluated the pathological specimens and classified the flow types according to the ISSVA classification. The MR imaging findings and the pathological diagnoses of the high and low flow
vascular anomalies were then compared.
Results: A total of 27 patients were included in this study. Eleven patients had a final histopathologic diagnosis of low flow vascular malformations and 16 patients had a diagnosis of high flow lesions. The MRI features such as flow void artifact, phleboliths, hypersignal intensity on T1W GRE images, arterial enhancement on dynamic post-gadolinium MRA, showed no difference between these two groups. Nine of 11 (81.8%) low flow vascular anomalies and 7 of 16 (43.8%) high flow vascular malformations had concordant MR imaging diagnosis with pathological result. The characteristics of the patients, lesion size and presence or absence of specific pulse sequences were not different between the groups of concordant and discordant flow type classification.
Conclusion: We have documented the MR imaging features, which shared by low flow and high flow vascular malformations. The ability of MRI to distinguish low flow from high flow lesions based on pathologic diagnosis was limited in our study. Soft tissue vascular malformations: differentiating flow types by MR imaging and comparison with histopathology