Giant cell tumor of the tendon sheath: Magnetic resonance imaging findings in 38 patients.

The present study aimed to investigate the value of magnetic resonance imaging (MRI) in the diagnosis of giant cell tumor of the tendon sheath (GCTTS), including localized (L-) and diffuse (D-) types. A total of 38 patients with GCTTS, including 31 with L-GCTTS and 7 with D-GCTTS, diagnosed by surgery and pathology, were retrospectively analyzed. All patients underwent MRI examination. Of the 31 patients with L-GCTTS, the tumors were located in the hand and wrist (18 patients), the ankle and foot (10 cases), the knee joint (2 cases) and the temporomandibular joint (1 case). All 31 lesions were either located in relation to a tendon or were partially/completely enveloping it and all were well marginated. With respect to the 7 D-GCTTS patients, the tumors were located in the ankle and foot (6 cases) or the hand and wrist (1 cases). All 7 lesions presented as an aggressive soft tissue mass infiltrating the tendon sheath and adipose tissue around the joint. The characteristic internal signal of GCTTS, including L-GCTTS and D-GCTTS, was demonstrated by MRI examination. MRI is currently the optimal modality for preoperative assessment of tumor size, extent and invasion of adjacent joint and tenosynovial space.

[Cerebral lesions of DWI hyperintensity in patients with subacute stroke assessed by intravoxel incoherent motion technique].

OBJECTIVE: To investigate the cerebral lesions of diffusion weighted imaging (DWI) hyperintensity in patients with subacute stroke with intravoxel incoherent motion (IVIM) technique. METHODS: The clinical data of 20 patients with ischemic stroke (3 to 7 d after onset) who underwent DWI and IVIM scanning between June 2014 and July 2015, were retrospectively analyzed. The parameters from IVIM including slow diffusion coefficient (D), fast diffusion coefficient (D(*)) and perfusion fraction (f) were processed. DWI hyperintensity was segmented by its signal intensity greater than the mean+2 standard deviations of the value in the homologous contralateral region. Then, DWI hyperintensity was classified into two regions of interest (ROIs): infarction core and peri-core with the ADC threshold of 0.55 × 10⁻³ mm²/s. The mirrored ROIs of infarction core and peri-core were also obtained. Then, we measured the values of ADC and D, D(*) and f in these ROIs. The ratios of ADC (rADC), D (rD), D(*) (rD(*)) and f (rf) were also calculated (e.g., rADC=ADCinfarction core/ADCmirrored region). RESULTS: Compared with mirrored region, ADC, D and f in the infarction core region decreased by 45% (P<0.001), 42% (P<0.001) and 32% (P<0.001), respectively; while ADC, D and f in the peri-core region decreased by 22% (P<0.001), 32% (P<0.001) and 8% (P=0.009), respectively. The values of rADC, rD, rD(*) and rf in the infarction core region were significantly lower than those in the peri-core region (all P<0.001). Pearson analysis showed that rADC was positively correlated with rf in the peri-core region (r=0.467, P=0.038). CONCLUSION: During subacute stage of stroke, compared to the infarction core region within DWI hyperintensity, D and f increase in the peri-core region of DWI hyperintensity, reflecting the increased water diffusion in microstructure and perfusion volume in microvasculature. This result shows that the potential reason for the heterogeneous ADC signal is associated with the disappearance of cellular edema and microvascular compensatory with increased blood volume.