MRI assessment of sacroiliitis for the diagnosis of axial spondyloarthropathy: comparison of fat-saturated T2, STIR and contrast-enhanced sequences.

OBJECTIVE: To evaluate whether there are significant differences between contrast-enhanced fat-saturated T1 weighted imaging and non-enhanced fat-suppression imaging for diagnosing sacroiliitis in patients with inflammatory back pain. METHODS: 92 patients, consisting of 46 males and 46 females (mean age: 34 years; range: 15-63 years), who met at least 4 out of 5 Assessment in SpondyloArthritis international Society criteria for inflammatory low back pain were enrolled in this study. All patients underwent MRI consisting of a coronal short tau inversion recovery (STIR) sequence, axial fat-saturated T2 weighted imaging (T2FS), and coronal and axial contrast-enhanced fat-saturated T1 weighted imaging (c & a T1CE). Two observers independently reviewed an image set of coronal STIR with axial T2FS, and an image set of c & a T1CE, at separate times. The degree of bone marrow edema and osteitis was evaluated from each image set. A decision for sacroiliitis positivity for each image set was made based on the findings. The presence of additional active inflammatory findings of spondyloarthropathy such as synovitis, enthesitis and capsulitis were also evaluated. RESULTS: Interobserver and intersequence agreement for the degree of bone marrow edema and osteitis were good or excellent in all quadrants. Cohen's kappa coefficients for sacroiliitis positivity between the two observers were 0.978 and 0.956, and Cohen's kappa coefficients between the two image sets for each observer were 0.892 and 0.870, respectively. The intersequence agreement of additional active inflammatory findings was substantial, and the interobserver agreement was almost perfect or substantial. CONCLUSION: STIR with T2FS image is comparable to T1CE image for diagnosing spondyloarthropathy. T1CE images may have a role in evaluating additional active inflammatory findings of spondyloarthropathy such as synovitis, enthesitis and capsulitis. Advances in knowledge: Coronal STIR with axial T2FS may be sufficient for diagnosis spondyloarthropathy without use of contrast administration.

Incremental Value of MR Cholangiopancreatography in Diagnosis of Biliary Atresia.

PURPOSE: To evaluate the incremental value of a combination of magnetic resonance cholangiopancreatography (MRCP) and ultrasonography (US), compared to US alone, for diagnosing biliary atresia (BA) in neonates and young infants with cholestasis. MATERIALS AND METHODS: The institutional review board approved this retrospective study. The US and MRCP studies were both performed on 64 neonates and young infants with BA (n = 41) or without BA (non-BA) (n = 23). Two observers reviewed independently the US alone set and the combined US and MRCP set, and graded them using a five-point scale. Diagnostic performance was compared using pairwise comparison of the receiver operating characteristics (ROC) curve. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value were assessed. RESULTS: The diagnostic performance (the area under the ROC curve [Az]) for diagnosing BA improved significantly after additional review of MRCP images; Az improved from 0.688 to 0.901 (P = .015) for observer 1 and from 0.676 to 0.901 (P = .011) for observer 2. The accuracy of MRCP combined with US (observer 1, 95% [61/64]; observer 2 92% [59/64]) and PPV (observer 1, 95% [40/42]; observer 2 91% [40/44]) were significantly higher than those of US alone for both observers (accuracy: observer 1, 73% [47/64], P = 0.003; observer 2, 72% [46/64], P = 0.004; PPV: observer 1, 76% [35/46], P = 0.016; observer 2, 76% [34/45], P = 0.013). Interobserver agreement of confidence levels was good for US alone (ĸ = 0.658, P < .001) and was excellent for the combined set of US and MRCP (ĸ = 0.929, P < .001). CONCLUSION: Better diagnostic performance was achieved with the combination of US and MRCP than with US alone for the evaluation of BA in neonates and young infants with cholestasis.