T2-star (T2*) -weighted magnetic resonance imaging of tenosynovial giant cell tumors

Abstract Objective Tenosynovial giant cell tumors (TSGCTs) are benign but aggressive lesions. Low to intermediate signal intensity on both T1- and T2-weighted images on magnetic resonance imaging (MRI) is characteristic, possibly reflecting hemosiderin deposition. T2-star (T2*)-weighted MR images reflect the paramagnetic deoxyhemoglobin, methemoglobin, or hemosiderin in the lesions and surrounding tissues. Materials and methods In 23 TSGCT patients (6 male and 17 females), the T2* MRI findings, the cystic changes confirmed on the T2-weighted image, potentially characteristic of TSGCT, were analyzed.Results The tumor locations included 10 large joints including nine knees and one ankle, 10 small joints including six fingers and four toes, and three wrists/hands. Ten diffuse and 13 localized tumors were predominantly located in the large joints and small joints, respectively. Cystic changes were seen in five (22%), predominantly in the large joints. The T2*-weighted images indicated three signal patterns of low, iso and high signal intensity compared to muscle. The low-, iso- and high-signal intensities were seen in 22 (96%), 23 (100%) and 12 (52%) of the locations, respectively. To distinguish TSGCTs from the surrounding tissue, the low intensity T2*-weighted images and low to intermediate intensity T1-weighted images when compared to muscle and fluid, respectively were useful for the large joints. Low to intermediate intensity on T1- or T2-weighted images was useful to distinguish TSGCTs from subcutaneous tissue in the small joints.Discussion MRI using T2*-, as well as T1 and T2-weighted images, is useful to assess the extent of TSGCTs within tissue, which is important for surgical planning.Institutional Review Board ApprovalThis report has been approved by the institutional review board of our institution (R2499).