1 Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York2 Department of Radiology, Institut du Cancer de Montpellier, Montpellier, France3 Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, New York4 Department of Radiology, Weill-Cornell Medical College, New York, New York
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BACKGROUND:Few publications exist regarding gadolinium-enhanced sequences in rectal MRI. None have evaluated its potential impact on patient management.OBJECTIVE:This study aimed to assess whether gadolinium-enhanced sequences, including dynamic contrast enhancement, change radiologic interpretation and clinical management of rectal cancer.DESIGN:This is a retrospective analysis of 100 rectal MRIs (50 baseline and 50 postneoadjuvant treatment), both without and with gadolinium-enhanced sequences. Treatment plans were rendered based on each radiologic interpretation for each case by a single experienced surgeon. Differences in radiologic interpretation and management were statistically analyzed.SETTINGS:The study was conducted at the Memorial Sloan Kettering Cancer Center.PATIENTS:Patients undergoing rectal MRI between 2011 and 2015 for baseline tumor staging and/or postneoadjuvant restaging were included.MAIN OUTCOME MEASURES:Primary outcome measures were changes in radiologic tumor stage, tumor margins, and surgical planning with the use of gadolinium at baseline and postneoadjuvant time points.RESULTS:At baseline, tumor downstaging occurred in 8 (16%) of 50 and upstaging in 4 (8%) of 50 with gadolinium. Postneoadjuvant treatment, upstaging occurred in 1 (2%) of 50 from T2 to T3a. At baseline, mean distances from tumor to anorectal ring, anal verge, and mesorectal fascia were not statistically different with gadolinium. However, in 7 patients, differences could have resulted in treatment changes, accounted for by changes in relationships to anterior peritoneal reflection (n = 4), anorectal ring (n = 2), or anal verge (n = 1). Postneoadjuvant treatment, distances to anorectal ring and anal verge (in centimeters) were statistically smaller with gadolinium (p = 0.0017 and p = 0.0151) but could not have resulted in clinically significant treatment changes.LIMITATIONS:This study was limited by its retrospective design.CONCLUSIONS:The use of gadolinium at baseline MRI could have altered treatment in 24% of patients because of differences in tumor stage or position. Postneoadjuvant treatment, gadolinium resulted in statistically smaller distances to sphincters, which could influence surgical decision for sphincter-preserving rectal resection. See Video Abstract at http://links.lww.com/DCR/A444.