title: Role of 18F-fluorodeoxyglucose Positron Emission Tomography in the Monitoring of Inflammatory Activity in Crohn's Disease.
abstract: Fluorine-fluorodeoxyglucose positron emission tomography (F-FDG PET) has recently attracted interest for the measurement of disease activity in Crohn's disease (CD). The aim of this study was to assess the utility of FDG-PET as a marker of progression of inflammatory activity and its response to treatment in patients with CD.
  
  
  
  Twenty-two patients with active CD were recruited prospectively to undergo FDG-PET scanning at 2 time points. All 22 index scans were used to assess sensitivity and specificity against a reference standard magnetic resonance imaging measure. Correlations with clinicopathological markers of severity (Harvey-Bradshaw Index, C-reactive protein, and calprotectin) were also performed. Of note, 17/22 patients participated in the longitudinal component and underwent scanning before and 12 weeks after the initiation of anti-tumor necrosis factor alpha therapy. Patients were subcategorized on the basis of a clinically significant response, and responsiveness of the PET measures was assessed using previously described indices. Of note, 5/22 patients took part in the test-retest component of the study and underwent scanning twice within a target interval of 1 week, to assess the reproducibility of the PET measures.
  
  
  
  The sensitivity and specificity of F-FDG PET were 88% and 70%, respectively. Standardized uptake value (SUV)-related PET measures correlated significantly both with C-reactive protein and Harvey-Bradshaw Index in cross-sectional and longitudinal analyses. (G)SUVMAX and (G)SUVMEAN demonstrated favorable responsiveness and reliability characteristics (responsiveness ratio of Guyatt >0.80 and % variability <20%) compared with volume-dependent FDG-PET measures. A proportion of the FDG signal (10%-30%) was found to originate from the lumen of diseased segments.
  
  
  
  F-FDG PET may be useful for longitudinal monitoring of inflammatory activity in CD.
authors.affiliation: *Division of Experimental Medicine, Department of Medicine, Imperial College London, London, United Kingdom; Departments of †Gastroenterology and ‡Imaging, Imperial College Healthcare NHS Trust, London, United Kingdom; §Imanova Centre for Imaging Sciences, London, United Kingdom; ‖Centre for Neuroimaging Sciences, King's College, London, United Kingdom; ¶Centre for Medical Imaging, University College London, London, United Kingdom; **Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom; and ††Division of Hepatology and Gastroenterology, Department of Surgery and Cancer, Imperial College Healthcare NHS Trust, London, United Kingdom.
authors.forename: Evangelos A
authors.initials: EA
authors.lastname: Russo
authors.forename: Sameer
authors.initials: S
authors.lastname: Khan
authors.forename: Ryan
authors.initials: R
authors.lastname: Janisch
authors.forename: Roger N
authors.initials: RN
authors.lastname: Gunn
authors.forename: Eugenii A
authors.initials: EA
authors.lastname: Rabiner
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Taylor
authors.forename: Paul M
authors.initials: PM
authors.lastname: Matthews
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Orchard
mesh_terms: D000328:Adult; D003424:Crohn Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18