Non-contrast enhanced MRI for assessment of uterine fibroids' early response to ultrasound-guided high-intensity focused ultrasound thermal ablation.

PURPOSE: To examine non-contrast enhanced MRI value to evaluate necrotic area and ablation rate of uterine fibroids after high-intensity focused ultrasound (HIFU) thermal ablation. METHOD: In total, 508 patients with 598 fibroids who underwent HIFU treatment were enrolled. Contrast-enhanced MRI (CE-MRI) with diffusion-weighted imaging (DWI)were performed before treatment and within two days post-treatment. DWI signal performance of post-operative fibroids was observed; apparent diffusion coefficient (ADC) and DWI signal values pre- and post-operation were measured. The volume of post-operative DWI signal change area and post-contrast enhanced fibroid necrosis area were compared. RESULTS: Average ADC and DWI signal values before HIFU treatment were higher than those post-operation; the difference was statistically significant before and after ablation (P < 0.05). After HIFU, 78.09 % (467 / 598) of DWI showed complete regular or irregular high-signal rings and 21.91 % (131 / 598) showed incomplete high-signal rings. No significant difference was noted between the complete high-signal ring volume on DWI and the non-enhanced volume (P > 0.05); however, this difference was statistically significant compared with the incomplete high-signal ring volume on DWI (P < 0.05). Two doctors had good agreements on evaluating the morphology of high-signal rings (κ > 0.75, P < 0.05). CONCLUSIONS: Combined with pre-operative T2WI and post-operative DWI, non-contrast enhanced MRI can effectively evaluate ablation rate for most patients with uterine fibroids.

Quantitative magnetic resonance imaging in patellar tendon-lateral femoral condyle friction syndrome: relationship with subtle patellofemoral instability.

OBJECTIVE: To investigate the correlation of patellar tendon-lateral femoral condyle friction syndrome (PTLFCFS) with subtle patellofemoral instability to explore its pathogenesis. MATERIALS AND METHODS: One hundred knees of 80 patients with PTLFCFS were analyzed retrospectively by retrieving magnetic resonance imaging (MRI) data over a 3-year period from our database. Seven quantitative parameters for evaluating patellofemoral stability were measured on MR images, including the Insall-Salvati ratio, tibial tuberosity-trochlear groove (TT-TG) distance, trochlear groove depth, medial trochlear/lateral trochlear length (MT/LT) ratio, medial trochlear/lateral trochlear height (MH/LH) ratio, lateral patellofemoral angle (LPA), and lateral trochlear inclination (LTI) angle. These patellofemoral parameters of the PTLFCFS group and the normal control group were compared (n = 88), and receiving-operator characteristic (ROC) curve analysis was conducted to determine the specificity and sensitivity of these parameters. RESULTS: The trochlear depth, MT/LT, LPA, and LTI angle were significantly lower (p < 0.001) and the Insall-Salvati ratio was significantly higher (p < 0.001) in the PTLFCFS group. However, the TT-TG distance and MH/LH ratio showed no significant difference (p = 0.231 and 0.073 respectively). The area under the ROC curve of the Insall-Salvati ratio, trochlear depth, MT/LT, LPA, and LTI angle were 0.925, 0.784, 0.8, 0.731, and 0.675 respectively. The efficiency of the Insall-Salvati ratio was the highest among those five parameters. CONCLUSION: This study verified the presence of subtle patellofemoral instability by measuring various patellofemoral parameters in patients with PTLFCFS. It confirmed that PTLFCFS is associated with subtle patellofemoral instability and could largely explain the pathogenesis of PTLFCFS.