MR Enterography of the Ileoanal Pouch: Descriptive Radiologic Analysis With Endoscopic and Pathologic Correlation.
OBJECTIVE
The purpose of this study was to describe the MR enterography (MRE) appearance of inflammation of the ileoanal pouch after ileal pouch-anal anastomosis (IPAA) surgery and to correlate it with pouch endoscopic and histopathologic findings.


METHODS
All MRE studies performed between October 1, 2007, and September 30, 2013, for patients who had previously undergone IPAA (n = 54) were retrieved. After review of medical records, the patients who underwent MRE, pouch endoscopy, and biopsy within 90 days (14 men, 14 women; mean age, 42.2 years; range, 24-67 years) were selected for inclusion in the study. Two blinded MRI radiologists in consensus retrospectively evaluated MRE studies for multiple MRI features. Two MRI scores were then calculated: an active and a composite inflammation score. A gastroenterologist retrospectively reviewed the pouch endoscopic images, and a pathologist reviewed the slides; both of these investigators were blinded. Both MRI scores were correlated with the pouch endoscopic and histopathologic findings.


RESULTS
The composite MRI score had strong positive correlation with the endoscopic score (r = 0.61; p = 0.0005) but weak positive correlation with the histopathologic score (r = 0.31; p = 0.10, not statistically significant). The active inflammation MRI score had moderate positive correlation with the endoscopic score (r = 0.57; p = 0.0017) and weak positive correlation with the histopathologic score (r = 0.20; p = 0.31, not statistically significant). An MRI score ≥ 4 indicated the best results, with sensitivity of 86%, specificity of 79%, positive predictive value of 80%, negative predictive value of 85%, and accuracy of 82% for pouch inflammation. A positive likelihood ratio of 4.00 and negative likelihood ratio of 0.18 were obtained.


CONCLUSIONS
In patients who have undergone IPAA surgery, the MRE findings strongly correlate with the pouch endoscopic findings with high sensitivity and positive predictive value for pouch inflammation. Therefore, MRE is a useful noninvasive test performed without ionizing radiation that can be used to evaluate patients with clinical symptoms and possibly alleviate the need for endoscopy in a select patient population.
1 Department of Radiology, Division of Abdominal Imaging, Beth Israel Deaconess Medical Center, Boston, MA.
Kamaldeep Singh
KS
Sahi
2 Department of Radiology, Division of Body MRI, Beth Israel Deaconess Medical Center, 330 Brookline Ave, TCC-4, Boston, MA 02215.
Karen S
KS
Lee
3 Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA.
Alan
A
Moss
4 Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA.
Eric
E
Yee
4 Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA.
Felicia
F
Allard
2 Department of Radiology, Division of Body MRI, Beth Israel Deaconess Medical Center, 330 Brookline Ave, TCC-4, Boston, MA 02215.
Alexander
A
Brook
2 Department of Radiology, Division of Body MRI, Beth Israel Deaconess Medical Center, 330 Brookline Ave, TCC-4, Boston, MA 02215.
Koenraad J
KJ
Mortele
D011125:Adenomatous Polyposis Coli / Q000601:surgery*; D000328:Adult; D000368:Aged; D000714:Anastomosis, Surgical; D001706:Biopsy; D003093:Colitis, Ulcerative / Q000601:surgery*; D039021:Colonic Pouches / Q000473:pathology*; D003287:Contrast Media; D003424:Crohn Disease / Q000601:surgery*; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D011183:Postoperative Complications / Q000175:diagnosis*; D012004:Rectal Neoplasms / Q000601:surgery*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
MR enterography; biopsy; ileal pouch–anal anastomosis; ileoanal pouch; pouch endoscopy; ulcerative colitis