Interobserver variability in the evaluation of chronic mesenteric ischemiawith gadolinium-enhanced MR angiography

Rationale and Objectives. The purpose of this study was to assess interobse rver variability in the interpretation of gadolinium-enhanced magnetic reso nance (MR) angiograms of splanchnic vessels in patients suspected of having chronic mesenteric ischemia (CMI). Materials and Methods. Two readers blinded to the initial interpretation re trospectively reviewed gadolinium-enhanced MR angiograms obtained for suspe cted CMI in 26 patients (20 women and six men; age range, 23-77 years; mean age, 61 years) who also underwent conventional angiography. Each reader gr aded the degree of stenosis based on the percentage diameter reduction of t he celiac artery (CA), superior mesenteric artery (SMA), and inferior mesen teric artery (IMA) by using a five-point ordinal scale: 0, no stenosis; 1, mild stenosis (<50%); 2, moderate stenosis (50%-75%); 3, severe stenosis (> 75%); 4, occluded artery. Using the conventional angiogram as a reference s tandard, authors determined sensitivity and specificity for each observer, assigning two thresholds (grades 2 and 3) as significant stenoses. A kappa statistic (kappa) measured interobserver agreement. Results. With grade 2 stenosis used as a threshold, cumulative accuracies f or detecting significant stenosis were 0.95 (95% confidence interval, 0.86- 0.99) for reader A and 0.97 (0.88-1.0) for reader B. Interobserver agreemen t for grading proximal splanchnic stenosis was 0.90 for CA, 0.92 for SMA, a nd 0.48 for IMA. Conclusion. Gadolinium-enhanced MR angiography is reproducibly accurate for detection of proximal splanchnic artery stenosis, with good to excellent i nterobserver agreement.