Intravoxel incoherent motion diffusion-weighted MR imaging for differentiation of benign and malignant musculoskeletal tumours at 3 T.

OBJECTIVE: To evaluate the intravoxel incoherent motion (IVIM) diffusion-weighted (DW) MRI for differentiating between benign and malignant musculoskeletal tumours at 3 T. METHODS: 65 patients with treatment-naïve musculoskeletal tumours (47 malignant and 23 benign lesions) who underwent 3 T MRI including IVIM DW imaging were included. IVIM-derived parameters included pure diffusion coefficient (D), perfusion related incoherent microcirculation (D*, pseudodiffusion coefficient), and perfusion fraction (f). IVIM parameters and mono-exponential apparent diffusion coefficient (ADC) were retrospectively measured by two independent musculoskeletal radiologists. RESULTS: D and ADC values of malignant tumours (923 ± 360, 965 ± 353 µm2 s-1, respectively) were significantly lower than those of benign tumours (1668 ± 546, 1689 ± 526 µm2 s-1) (p < 0.001). F values of malignant tumours (9.6%) were significantly higher than those of benign tumours (7.2%) (p = 0.021), whereas D* values showed no significant difference (p > 0.05). The area under the receiver operating characteristic (ROC) curve of D, ADC and f were 0.874, 0.880 and 0.671, respectively. Using cut-off values of D and ADC of 1200 µm2 s-1, the sensitivity, specificity and accuracy were 92, 83, 89%, 92, 87 and 90%, respectively. CONCLUSION: D and ADC may be more accurate and reliable for differentiation of malignant from benign musculoskeletal tumours than f and D* at 3 T IVIM DW imaging. Advances in knowledge: Among IVIM-derived parameters, D is more accurate and reliable in differentiating malignant from benign musculoskeletal tumours than f and D* at 3.0T IVIM DW imaging. There was no significant difference in the diagnostic performance of D and ADC.

Ultrasonographic diagnosis of snapping annular ligament in the elbow.

Elbow snapping by annular ligament is rare and may be difficult to diagnose, when this Epub ahead of print condition is not familiar. We report a case of elbow snapping by annular ligament diagnosed by ultrasonography, which was confirmed by arthroscopic observation. The ultrasonographic findings were thickening of the annular ligament and snapping in and out of the radiocapitellar joint during elbow flexion and extension on dynamic ultrasonography.

Visual MRI grading system to evaluate atrophy of the supraspinatus muscle.

OBJECTIVE: To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI). MATERIALS AND METHODS: Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, ≥ 60%; 2, 30-59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear. RESULTS: The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70-0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026). CONCLUSION: The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.

High prevalence of abnormal MR findings of the distal semimembranosus tendon: contributing factors based on demographic, radiographic, and MR features.

OBJECTIVE: The objective of our study was to determine the prevalence of thickening and signal alteration of the distal semimembranosus (SM) tendon on knee MRI and analyze the patient factors associated with abnormal MR findings of the distal SM tendon. MATERIALS AND METHODS: Knee MRI scans of 116 subjects (58 men, 58 women; mean age, 48.5 years; range, 18-79 years) who underwent knee surgery were evaluated to assess the distal SM tendons in terms of signal alteration and thickness. To determine the factors associated with MR findings of the distal SM tendon, we assessed demographic characteristics; Kellgren-Lawrence radiographic osteoarthritis grading; history of trauma; the condition of the cruciate ligaments, collateral ligaments, and menisci; and whether there were cystic lesions around the SM tendon. In addition, 55 control subjects with normal knee MRI findings based on the electronic MRI patient database who had anterior knee pain and did not undergo surgery were enrolled. RESULTS: Abnormal thickening of the distal SM tendon was found in 52.6% of knees and signal alteration in 44.8%. Univariate analysis revealed significant associations between abnormal thickening and age, body mass index, history of trauma, osteoarthritis, medial collateral ligament (MCL) thickening, and anterior cruciate ligament (ACL) tear. As for signal alteration, univariate analysis showed that age, body mass index, osteoarthritis, and MCL thickening were statistically significant factors. Multivariate binary logistic regression analyses showed that osteoarthritis and MCL thickening were the strong independent predictors in thickening and signal alteration of the distal SM tendon. CONCLUSION: Signal alteration and abnormal thickening of the distal SM tendon on MRI are frequently seen in daily practice. These MR findings are strongly associated with osteoarthritis and MCL thickening.

Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

OBJECTIVE: To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique. METHODS: The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDI (vol)) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDI (vol ) and the effect of ATT on image noise while adjusting for other variables including abdominal circumference. RESULTS: CTDI (vol) varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI (vol) and ATT (p = 0.61). ATT did not significantly affect CTDI (vol) (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI (vol) (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38. CONCLUSION: The amount of stool and fluid tagging does not significantly affect radiation exposure.

Sclerotherapy of peritoneal inclusion cysts: a long-term evaluation study.

BACKGROUND: This study was designed to evaluate the long-term results of sclerotherapy for the treatment of peritoneal inclusion cysts (PICs). METHODS: Twenty-nine patients with 30 PICs were included in the study. Sclerotherapy was performed with use of povidone-iodine in 13 PICs and ethanol in 17 PICs, until the drained volume was less than 5 mL. Patients were evaluated after 1 month, 4 months, and then every 6 months by clinical assessment and ultrasound examination. RESULTS: Sclerotherapy was technically successful for all 30 PICs. During the follow-up period of 7-94 months (mean: 38.0 months), the PICs completely disappeared in 15 lesions and the diameter of the cysts decreased more than 50% without symptoms for the other 12 lesions. The overall long-term success rate was 90.0% (27/30). There was no significant difference in the success rate between the use of povidone-iodine (92.3%, 12/13) and ethanol (88.2%, 15/17). Recurrence of a PIC occurred in three patients. Two PICs completely regressed without further recurrence after re-sclerotherapy. Remaining one was removed under surgery. CONCLUSIONS: Sclerotherapy following catheter insertion is a safe, effective, and reliable method for the treatment of PICs. Long-term regular follow-up months may not be necessary.