The level of 18F-FDG uptake measured by maximal standardized uptake value (SUVmax) from a combined PET and CT enterography in a single exam may be an objective indication of active inflammation in segments of bowel that are abnormal on CT enterography, according to a study published in this month's Journal of Nuclear Medicine.
The researchers combined 18F-FDG PET and CT enterography in a single exam and compared the level of 18F-FDG uptake measured by SUVmax with the CT enterography patterns of disease activity found in patients with Crohn's disease.
David Groshar, MD, director at the department of nuclear medicine at Rabin Medical Center, Beilinson Hospital in Petach Tikva, Israel, and colleagues included 28 patients suspected of having active Crohn's disease in the study. All patients underwent PET/CT enterography. The researchers also obtained CT enterography measurements of thickness and enhancement and noted normal segments of the ileum and colon.
For segments detected on CT enterography, a volume of interest was placed by the researchers on the fused 18F-FDG PET scan, and the SUVmax was obtained.
Groshar and colleagues found that of the 28 patients with suspected active Crohn's disease, 22 had 85 abnormal segments and six had no abnormal segments. SUVmax was significantly higher in the abnormal segments (5.0) than in the normal segments (2.1).
A good correlation was found between SUVmax with CT enterography measurements of mural thickness and enhancement, noted the authors. There was also a significant difference in SUVmax between the three levels of disease activity found by intramural attenuation, perienteric fat infiltration and the comb sign on CT enterography.
“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. Future studies are warranted to evaluate if combined PET/CT enterography has an important role in the clinical management of Crohn's disease,” concluded Groshar and colleagues.