PET/CT Enterography in Crohn Disease: Correlation of Disease Activity on CT Enterography with ¹⁸F-FDG Uptake

Abstract

We combined 18 F-FDG PET and CT enterography in a single examination and compared the level of 18 F-FDG uptake measured by maximal standardized uptake value (SUVmax) with the CT enterography patterns of disease activity found in patients with Crohn disease (CD). Methods: Twenty-eight patients (mean age, 37.5 y; 11 male and 17 female) suspected of having active CD underwent PET/CT enterography. Abnormal bowel segments recognized on CT enterography were graded qualitatively for the presence of perienteric fat infiltration, the comb sign, and intramural attenuation and by quantitative measurements of mural enhancement (Hounsfield units) and thickness (mm). Also, for each patient, normal segments of the ileum and colon were noted, and CT enterography measurements of thickness and enhancement were obtained. For segments detected on CT enterography, a volume of interest was placed on the fused 18 F-FDG PET scan, and the SUVmax was obtained. Results: Of the 28 patients with suspected active CD, 22 had 85 abnormal segments and 6 had no abnormal segments. SUVmax was significantly higher in the abnormal segments than in the normal segments (5.0 6 2.5 [95% confidence interval, 4.5-5.5] and 2.1 6 0.69 [95% confidence interval, 1.9-2.2], respectively; P , 0.0001). A good correlation was found between SUVmax with CT enterography measurements of mural thickness and enhancement (P , 0.00001). There was a significant difference in SUVmax between the 3 levels of disease activity found by intramural attenuation, perienteric fat infiltration, and the comb sign on CT enterography. SUVmax was significantly higher when there were intense CT enterography findings of active disease (P , 0.001). Conclusion: SUVmax assessment may allow an objective, reliable indication of the grade and severity of inflammation activity in abnormal segments of the bowel detected by CT enterography.

Longitudinal quantification of inflammation in the murine dextran sodium sulfate-induced colitis model using μPET/CT1

“…13 Very recently, FDG-PET/CT has proven to be useful for both the diagnosis and follow-up of human IBD, although some concerns are raised on the high radiation exposure during these PET investigations. [14][15][16] Brewer et al 2 described the use of FDG-PET in various animal models of chronic colitis and showed that the cellular source of the increased FDG-signal in the setting of chronic intestinal inflammation is CD4 þ T cells. Acute DSS-colitis is highly lymphocyte-independent and principally mediated by neutrophils and, to a lesser degree, macrophages.…”

Imaging of the small bowel: Crohn’s disease in paediatric patients

“…Groshar et al [93] showed a statistically significant difference in mean SUV max among the different mural patterns revealed on CT enterography: intramural edema (active inflammation), intramural soft tissue attenuation (inflammatory infiltrate), and intramural fat (chronic inflamma- tion). Therefore, PET-CT data could help to distinguish between acute inflammation and fibrotic strictures.…”

The Role of Positron Emission Tomography in Inflammatory Bowel Disease

“…There is still limited evidence on these imaging methods both in adult and in pediatric IBO patients, but there is a good correlation between PET findings and disease activity (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29).…”