ORIGINAL ARTICLE Diagnostic Value of Noninvasive Combined Fluorine-18 Labeled Fluoro-2-deoxy-D-glucose Positron Emission Tomography and Computed Tomography Enterography in Active Crohn’s Disease Anis Ahmadi, MD,* Qin Li, MS, † Keith Muller, PhD, † Dennis Collins, MD,* John F. Valentine, MD,* Walter Drane, MD, ‡ and Steven Polyak, MD* Background: The role of combined localized positron emission tomography (lPET) and computed tomography enterography (CTe) in Crohn’s disease is unclear. We examined if this imaging modality using fluorine-18 labeled-fluoro-2-deoxy-D-glucose (FDG) could more effectively identify disease activity. Methods: 52 lPET-CTe scans were analyzed in this retrospec- tive study. CTe scores and FDG uptake were quantified. Correla- tions of CTe scores and standard uptake value (SUV) with C- reactive protein (CRP), erythrocyte sedimentation rate (ESR), short Inflammatory Bowel Disease Questionnaire (sIBDq), and Harvey–Bradshaw index (HBI) were estimated using Pearson analysis. Imaging scores were compared to medical outcome by logistics regression model. Results: CTe scores correlated with SUV, but additional abnor- mal segments of small bowel were not identified. In all, 38 (79%) abnormal CTe segments demonstrated increased FDG uptake with mean SUVmax 4.77; 10 (21%) abnormal CTe segments lacked FDG accumulation, with mean SUVmax 1.27. There was no cor- relation between SUVmax and CRP, ESR, sIBDq, or HBI. There were no significant differences in clinical indices, biochemical pa- rameters, and presence of multiple abnormal segments between medical responders and uptake were associated with failed medi- cal therapy (P ¼ 0.001). Conclusions: PET scanning added to CTe did not identify addi- tional abnormal segments when compared to CTe alone. Abnor- mal segments with mucosal enhancement on CTe that did not accumulate FDG were significantly associated with failure of medical therapy. A larger trial is warranted to confirm if com- bined lPET-CTe has an important role in the clinical management of stricturing Crohn’s disease. (Inflamm Bowel Dis 2010;16:974–981) Key Words: positron emission tomography, enterography, Crohn’s disease, small bowel E valuation of inflammation severity in Crohn’s disease (CD) is an essential part of effective patient care. A clinician’s assessment can lead to expensive and life-alter- ing decisions such as advancement of medical therapy and surgery. There is a continuing need to improve our tools used to evaluate active inflammation in inflammatory bowel disease (IBD). Current investigative tools used in the assessment of CD include clinical disease activity indi- ces, radiologic imaging, endoscopy, and biochemical markers of inflammation. Radiologic imaging encompasses a number of options, including computed tomography (CT), magnetic resonance imaging (MRI), positron emis- sion tomography (PET), small bowel follow-through (SBFT) fluoroscopy, CT enteroclysis, and CT enterography (CTe). Unfortunately, none of the studies described above provide all the necessary information needed to identify and evaluate disease activity. The relapsing nature of CD often requires repeated evaluation and testing of patients. Therefore, identification of effective noninvasive tests to help determine disease activity and associated complica- tions are attractive in that they improve patient care, mini- mize risk, and can be more cost-effective. Certain pheno- types of CD, such as those with small bowel inflammation, are difficult to assess using endoscopic methods, which have led to the study of noninvasive imaging techniques to evaluate small bowel disease. Additional supporting information may be found in the online version of this article. Received for publication May 22, 2009; Accepted September 20, 2009. From the *Department of Medicine, Division of Gastroenterology, University of Florida College of Medicine, Gainesville, FL, † Department of Epidemiology and Health Policy Research, Division of Biostatistics, Gainesville, FL, ‡ Department of Radiology, Division of Nuclear Medicine, University of Florida College of Medicine, Gainesville, FL. Reprints: Steven Polyak, MD, Department of Medicine, Division of Gastroenterology, University of Florida College of Medicine, 1600 SW Archer Rd., PO Box 100214, Gainesville, FL, 32610 (e-mail: steven. polyak@medicine.ufl.edu) Copyright V C 2009 Crohn’s & Colitis Foundation of America, Inc. DOI 10.1002/ibd.21153 Published online 2 November 2009 in Wiley InterScience (www. interscience.wiley.com). Inflamm Bowel Dis  Volume 16, Number 6, June 2010 974