Background and aim: Scintigraphy using Tc-99m or In-111 labeled proteins is an important diagnostic modality for diagnosis of protein losing enteropathy (PLE). We systematically reviewed the available literature regarding the accuracy of scintigraphy using Tc-99m or In-111 labeled proteins for diagnosis of PLE.
Methods: Medline and SCOPUS were searched using (("protein losing") AND ("scintigraphy" OR "Nuclear Medicine")) as keywords without any language or date limit. All studies on the accuracy of scintigraphy using Tc-99m or In-111 labeled proteins in PLE were included in the systematic review.
Results: Overall 12 studies were included in our study. Pooled sensitivity and specificity were 87% [81-92%], and 62% [51-72%], respectively. Tc-99m labeled tracers had higher sensitivity but lower specificity compared to In-111 labeled ones. Delayed imaging could increase the sensitivity of imaging despite the lower specificity compared to the early images. Restriction of the analyses to larger studies (more than 10 patients) and to studies with the gold standard of fecal alphal-antitrypsin did not change the pooled indices.
Conclusion: Scintigraphy using Tc-99m or In-111 labeled proteins has high sensitivity for diagnosis and localization of PLE. Using Tc-99m labeled tracers and delayed imaging can further increase the sensitivity. Despite the high sensitivity, specificity of scintigraphy is suboptimal and false positive abdominal activities can limit the usefulness of this imaging method.