Accuracy of Oral Gallium Citrate Scintigraphy in assessment of inflammatory activity of Crohn's disease.

Aim: The main goal in Crohn´s disease (CD) is a sustained suppression of inflammatory activity associated with mucosa healing in endoscopic evaluation. During clinical routine, there are small numbers of good markers to monitor inflammatory activity under treatment. We postulated that Oral Gallium Citrate Scintigraphy is able to mark inflammatory disease in mucosa and deep inflammation in CD, when used in oral form.

Objective: Measure the accuracy of Oral Gallium Citrate Scintigraphy in intestinal inflammatory activity of Crohn´s disease.

Patients And Methods: In a prospective consecutive cross-sectional study from January 2018 to June 2019, the ileocolonic region of 32 patients with CD were studied by dividing into four regions of interest (ROI) from the ileum to the rectum. A total of 128 intestinal segments were analyzed in cluster data. Accuracy values of Oral Gallium Scintigraphy and colonoscopy tests were evaluated with the histological reference test. Values of the respective receiver operating characteristic (ROC) curves were obtained  and compared. The reliability between the tests was evaluated by Kappa statistical with the segment-level analyses using variance adjustments. All statistical analyses were performed with a test significance level of 0.05.

Results: The study population included 32 patients with CD (10 men, 22 women; average age 39 years). Disease time was five years on average. Anti-TNFs treatment was found in 71%. The most found phenotype of the Montreal classification was L3. Differences in ROC curves for colonoscopy (0.94) and Oral Ga Scintigraphy (0.96) did not show significant value (p = 0.32). The sensitivity of scintigraphy to detect intestinal inflammatory activity in CD was 64%, specificity of 96% and accuracy of 84%. A high agreement was found between oral scintigraphy and histological measurements with kappa = 0.64.

Conclusions: Oral Ga Scintigraphy had similar accuracy and agreement compared to colonoscopy in the identification of inflammatory activity in Crohn´s Disease. This new approach may be useful and less invasive for long term follow-ups.