Local grading of inflammation in chronic Inflammatory Bowel Disease (IBD) by dynamic tissue perfusion measurement (PixelFlux-method)
Objectives: The novel method of dynamic tissue perfusion measurement in color Doppler sonographic videos was applied to sonographic inflammation grading in IBD (Crohn disease [CD] and ulcerative colitis [UC]) as well as to healthy probands to evaluate the potential of the new method compared to established inflammation grading techniques.
Methods: Perfusion intensity was measured by the PixelFlux-method (www.chameleon-software.de) in standardized DICOM video clips of the intestinal wall in 34 healthy subjects (5–18 years), 14 CD patients (8–16 years) and 19 UC (12–18 years) patients under defined and constant conditions. Bowel wall perfusion in CD was compared to the Pediatric Crohn Disease Activity Index (PCDAI) in 12 patients.
Results: Compared to healthy subjects perfusion was significantly elevated in CD (small bowel: 0.025 vs. 0.095cm/s; p<0.001– large bowel: 0.012 vs0.082cm/s). No differences of perfusion between moderate and high PCDAI could be demonstrated despite a weak significant overall correlation. In UC similar significant increase in perfusion intensity was demonstrated (p<0,001) large bowel: 0,113cm/s, small bowel 0,055cm/s). Histologic activity scores (encompassing ulceration, abscess formation, wall infiltration by polymorphonuclear neutrophils and lymphocytes, disturbed crypt architecture) were significantly correlated to local intestinal wall perfusion in UC.
Conclusion: The dynamic perfusion quantification of the inflamed bowel wall correlates significantly to histologic activity markers and is superior to activity evaluation by PCDAI. The PixelFlux-method constitutes thus the bridge from invasive to noninvasive inflammation grading in IDB and has potential to spare endoscopies.