RT Journal Article SR Electronic T1 Noninvasive Assessment of Acute Graft-Versus-Host Disease of the Gastrointestinal Tract After Allogeneic Hemopoietic Stem Cell Transplantation Using 18F-FDG PET JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1899 OP 1905 DO 10.2967/jnumed.121.263688 VO 63 IS 12 A1 Cherk, Martin H. A1 Khor, Robert A1 Barber, Thomas W. A1 Yap, Kenneth S.K. A1 Patil, Sushrut A1 Walker, Patricia A1 Avery, Sharon A1 Roberts, Stuart A1 Kemp, William A1 Pham, Alan A1 Bailey, Michael A1 Kalff, Victor YR 2022 UL http://jnm.snmjournals.org/content/63/12/1899.abstract AB Acute graft-versus-host disease of the gastrointestinal tract (acute GIT-GVHD) often complicates allogeneic hemopoietic stem cell transplantation (AHSCT). 18F-FDG PET/CT is known to detect active inflammation and may be a useful noninvasive test for acute GIT-GVHD. The objective of this study was to evaluate the diagnostic utility of 18F-FDG PET/CT to noninvasively assess patients with clinically suspected acute GIT-GVHD. Fifty-one AHSCT patients with clinically suspected acute GIT-GVHD prospectively underwent 18F-FDG PET/CT scanning followed by upper and lower GIT endoscopy within 7 d. Endoscopic biopsies of 4 upper GIT and 4 colonic segments were obtained for histology to compare with corresponding quantitative segmental 18F-FDG PET/CT SUVmax. Receiver-operating-characteristic curve (ROC) analysis was performed to determine predictive capacity of 18F-FDG PET/CT SUVmax for acute GIT-GVHD. A separate qualitative visual 18F-FDG PET/CT analysis was also performed for comparison. Results: Twenty-three of 51 (45.1%) patients had biopsy-confirmed acute GIT-GVHD, with 19 of 23 (82.6%) having upper GIT and 22 of 22 (100%) colonic involvement. One of 23 patients did not undergo a colonoscopy. GVHD involved the entire colon contiguously in 21 of 22 patients. For quantitative analysis, histology from 4 upper GIT and 4 colonic segments were compared with 18F-FDG PET/CT SUVmax. Colonic segments positive for GVHD had a higher SUVmax (4.1 [95% CI, 3.6–4.5]) than did normal colonic segments (2.3 [1.9–2.7], P = 0.006). No difference was demonstrated in upper GIT segments. Quantitative 18F-FDG PET/CT yielded a 69% sensitivity, 57% specificity, 73% negative predictive value, and 59% positive predictive value for the detection of GVHD compared with 70%, 76%, 76%, and 68%, respectively, for qualitative analysis. Conclusion: 18F-FDG PET is a useful noninvasive diagnostic test for acute GIT-GVHD, which when present always involves the colon and usually in its entirety, suggesting colonic biopsy obtained by sigmoidoscopy is adequate for histologic confirmation when acute GIT-GVHD is suspected. Of note, 18F-FDG PET cannot distinguish acute GIT-GVHD from non-GVHD inflammatory changes in the colon.