PANCREATIC FLUID COLLECTIONS PRIOR TO INTERVENTION - EVALUATION WITH MR-IMAGING COMPARED WITH CT AND US

PURPOSE: To evaluate the ability of magnetic resonance (MR) imaging to depict solid debris within pancreatic collections prior to interventi on and to help assess drainability, as well as to compare MR findings with those obtained at computed tomography (CT) and ultrasound (US). M ATERIALS AND METHODS: Nineteen collections in 18 patients were evaluat ed with MR imaging CT, and US prior to drainage. Prospective, blinded interpretations of imaging studies by three independent readers (each interpreted all the images obtained with only one modality) evaluated collection characteristics (debris, consistency, septation, wall thick ness, and irregularity) and predicted drainability. Findings were comp ared with clinical diagnosis and clinical outcome of drainage. RESULTS : MR imaging and CT depicted all collections; US failed to depict two collections. In nine patients with subacute necrotic collections, soli d debris was seen in eight (89%) at MR imaging, in two (22%) at CT, an d in eight (89%) at US. In seven patients with pseudocysts, debris was seen in two (28%) at MR imaging and in none at CT, as well as in six (100%) of six at US. A collection was defined as ''not drainable'' on the basis of the depiction of solid necrotic debris more than 1 cm in diameter. With this definition, statistically significant differences between sensitivity and specificity values, respectively, were found f or the prediction of actual drainability: MR imaging, 100% and 100%; C T, 25% and 100%; US, 88% and 54%. CONCLUSION: Predrainage MR imaging s hould be performed in patients with subacute pancreatic collections to avoid infectious complications from unrecognized necrotic debris that cannot be removed with use of standard pseudocyst drainage techniques .