| ObjectiveTo investigate the diagnostic value of MSCT and3.0T MRI for evaluating the pounch of the normal group, the critical group and the pouchitis group according to pounchitis disease activity index(PDAI); to establish imaging scoring systems and to evaluate the efficacies of different imaging methods for assessing pounch condition.Materials and MethodsTotal26patients who underwent ileal pouch-anal anastomosis (IPAA) and regularly followed up in TianJin Medical University General Hospital between Mar.2010to Sept.2011enrolled in this study with informed,14males and12females, aged18to57years, mean35.6±12.3years.They were divided into the normal group, the critical group and the pouchitis group according to PDAI:patients who PDAI<3were divided into normal group,3<PDAI<7into critical group, PDAI>7into pouchitis group.21cases flat underwent unenhanced CT scan;20cases underwent dynamic contrast-enhanced CT(DCE-CT);25cases underwent all of the unenhanced MRI scan, diffusion weighted imaging and dynamic contrast-enhanced MRI(DCE-MRI). After the examinations, the image were transmissed to an offline workstation. Two experienced radiologist reviewed the images independently and blindly. The bowel wall thickness, short diameter of the largest adjacent lymph node, apparent diffusion coefficient (ADC) value and the incidences of adjacent lymph nodes, mensentric stranding and complications were measured, then the time-density curves and time-signal intensity curves (TICs) of three groups after DCE-CT and DCE-MRI were plotted, time to peak (TTP) value and relative enhancement rate (Er) after correction by obturator muscle were calculated, the differences of imaging findings measured above were compared among the three groups. Then the imaging findings were evaluated by a three-scales scoring system as0-2points (0:mild;1: moderate;2:severe). Four imaging scoring systems were established, then their diagnostic performances were assessed by receiver operating characteristic (ROC), the sensitivity, specificity, positive predictive value and negative predictive value were calculated. At last, imaging scoring systems were compared with each other according to PDAI respectively.Results1. There were significant differences of bowel thickness between any of two groups of the three groups in four imaging methods, the bowel thickness of pouchitis group [(4.7±2.8) mm;(4.7±3.0) mm;(3.7±2.0) mm;(4.1±2.1) mm] was significantly increased than that of critical group [(2.3±0.6) mm;(2.6±1.0) mm;(1.8±0.3) mm;(2.5±0.2) mm] and normal group [(2.1±0.3) mm;(2.1±0.6) mm;(1.5±0.3) mm;(2.1±0.2) mm], but there was no significant difference between critical group and normal group. There were also no significant differences of short diameter of the largest adjacent lymph node and incidences of adjacent lymph nodes, mensentric stranding among the three groups(p>0.05). There were significant differences in the incidences of complications of the normal group,critical group and pouchitis group in four imaging methods (0,8.3%versus66.7%;0,9.1%versus66.7%;0,14.3%versus66.7%;0,14.3%versus66.7%;p<0.05), but there was also no significant difference between any two groups.2. The bowel wall of pouchitis group significantly hyperenhanced; the bowel wall of critical group may isoenhanced or unenhanced; the normal group was unenhanced. The type of TDCs and TICs in pouchitis group were fast rising and falling slow, but the TTP of TICs was shorter than TDC curves. However, the type of TDCs and TICs in normal group and critical group were rising and falling slowly. There were no significant differences of TTP among the three goups(p>0.05). Er differed significantly among the normal group, critical group and pouchitis group [(85.0±31.3)%,(100.0±33.5)%versus (162.0±111.6)%;(79.7±24.4)%,(104.3±62.4)%vesus (226.9±111.0)%; p<0.05] in DCE-CT and DCE-MRI examinations, but there were no significant differences beween any two groups.3.There were significant differences in the ADCs among the normal group, critical group and pouchitis group[(2.7±0.4)×10-3mm2/s,(1.8±0.2)×10-3mm2/s versus (1.3±0.1)×10-3mm2/s], between any two groups, the ADC of pouchitis group were significantly decreased than that of critical group and normal group, but there was no significant differences between critical group and normal group.4. Four imaging scoring systems were established. Area under curve(AUC) points for using ROC to differentiate normal group and critical group were0.545,0.591,0.758and0.886respectively in four imaging methods, and the Kappa value were0.348,0.380,0.680,0.792; area under curve(AUC) points for using ROC to differentiate critical group and pounchitis group were0.955,0.939,1.000and1.000respectively, and the Kappa value were0.545,0.659,1.000,1.000. Therefore, the diagnostic performance of DCE-MRI scoring system is of best and the correlation between DCE-MRI scoring system and PDAI is the strongest.ConclusionCT and MRI examination can reliably distinguish normal pouch with pouchitis and critical pouch with pouchitis who underwent IPAA, but can’t distinguish normal pouch with critical pouch; among the four imaging scoring systems established according imaging findings of pouchitis, DCE-MRI examination scoring system the best one to identify the normal group, the critical group and pouchitis group. |
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