Diagnostic performance of susceptibility-weighted magnetic resonance imaging for the assessment of sub-coracoacromial spurs causing subacromial impingement syndrome.

OBJECTIVES: To evaluate the potential of susceptibility-weighted-magnetic-resonance-imaging (SWMR) for the detection of sub-coracoacromial spurs in patients with clinically suspected subacromial impingement syndrome (SAIS), compared to standard MR-sequences and radiographs. METHODS: Forty-four patients with suspected SAIS were included. All patients underwent radiography, standard MRI of the shoulder and SWMR. Radiograph-based identification of sub-coracoacromial spurs served as goldstandard. Radiographs identified twenty-three spurs in twenty-three patients. Twenty-one patients without spur formation served as reference group. Detection rate, sensitivity/specificity and interobserver-agreements were calculated. Linear regression was applied to determine the relationship between size measurements on radiographs and MRI. RESULTS: Detection rates for spurs on standard MRI and SWMR were 47.8 % and 91.3 % compared to radiography (p<0.001). SWMR demonstrated a sensitivity of 97.7 % (CI=0.92-1) and a specificity of 91.3 % (CI=0.788-1) for the identification of spurs. Standard MR-sequences achieved a sensitivity of 47.8 % (CI=0.185-0.775) and a specificity of 80.8 % (CI=0.642-0.978). Size measurements between SWMR and radiography showed a good correlation (R2=0.75;p<0.0001), while overestimating lesion size (5.7±1.2 mm; 4.3±1.3 mm;p<0.0001). Interobserver-agreement for spurs was high on SWMR (R2=0.74;p<0.0001), but low on standard MRI (R2=0.24;p<0.0001). CONCLUSIONS: SWMR allows a reliable detection of sub-coracoacromial spur formation in patients with SAIS and is superior to standard MR-sequences using radiography as goldstandard. KEY POINTS: • SWMR has the potential to reliably identify sub-coracoacromial spurs without radiation exposure. • SWMR provides comparable detection rates to conventional radiography for sub-coracoacromial spur formation. • SWMR yields higher detection rates compared to standard-MR regarding sub-coracoacromial spur formation. • SWMR can be implemented in routine shoulder MRI protocols.

Renal cell carcinoma with venous extension: prediction of inferior vena cava wall invasion by MRI.

BACKGROUND: Renal cell carcinoma (RCC) are accompanied by inferior vena cava (IVC) thrombus in up to 10% of the cases, with surgical resection remaining the only curative option. In case of IVC wall invasion, the operative procedure is more challenging and may even require IVC resection. This study aims to determine the diagnostic performance of contrast-enhanced magnetic resonance imaging (MRI) for the assessment of wall invasion by IVC thrombus in patients with RCC, validated with intraoperative findings. METHODS: Data were collected on 81 patients with RCC and IVC thrombus, who received a radical nephrectomy and vena cava thrombectomy between February 2008 and November 2017. Forty eight patients met the inclusion criteria. Sensitivity and specificity as well as the positive and negative predictive values were calculated for preoperative MRI, based on the assessments of the two readers for visual wall invasion. Furthermore, a logistic regression model was used to determine if there was an association between intraoperative wall adherence and IVC diameter. RESULTS: Complete occlusion of the IVC lumen or vessel breach could reliably assess IVC wall invasion with a sensitivity of 92.3% (95%-CI: 0.75-0.99) and a specificity of 86.4% (95%-CI: 0.65-0.97) (Fisher-test: p-value< 0.001). The positive predictive value (PPV) was 88.9% (95%-CI: 0.71-0.98) and the negative predictive value reached 90.5% (95%-CI: 0.70-0.99). There was an excellent interobserver agreement for determining IVC wall invasion with a kappa coefficient of 0.90 (95%CI: 0.79-1.00). CONCLUSIONS: The present study indicates that standard preoperative MR imaging can be used to reliably assess IVC wall invasion, evaluating morphologic features such as the complete occlusion of the IVC lumen or vessel breach. Increases in IVC diameter are associated with a higher probability of IVC wall invasion.

Diagnostic performance of susceptibility-weighted magnetic resonance imaging for the detection of calcifications: A systematic review and meta-analysis.

Since its introduction, susceptibility-weighted-magnetic resonance imaging (SW-MRI) has shown the potential to overcome the insensitivity of MRI to calcification. Previous studies reporting the diagnostic performance of SW-MRI and magnetic resonance imaging (MRI) for the detection of calcifications are inconsistent and based on single-institution designs. To our knowledge, this is the first meta-analysis on SW-MRI, determining the potential of SW-MRI to detect calcifications. Two independent investigators searched MEDLINE, EMBASE and Web of Science for eligible diagnostic accuracy studies, which were published until March 24, 2017 and investigated the accuracy of SW-MRI to detect calcifications, using computed tomography (CT) as a reference. The QUADAS-2 tool was used to assess study quality and methods for analysis were based on PRISMA. A bivariate diagnostic random-effects model was applied to obtain pooled sensitivities and specificities. Out of the 4629 studies retrieved by systematic literature search, 12 clinical studies with 962 patients and a total of 1,032 calcifications were included. Pooled sensitivity was 86.5% (95%-confidence interval (CI): 73.6-93.7%) for SW-MRI and 36.7% (95%-CI:29.2-44.8%) for standard MRI. Pooled specificities of SW-MRI (90.8%; 95%-CI:81.0-95.8%) and standard MRI (94.2; 95%-CI:88.9-96.7%) were comparable. Results of the present meta-analysis suggest, that SW-MRI is a reliable method for detecting calcifications in soft tissues.