Applicability of 99m Tc-Labeled Human Serum Albumin Scintigraphy in Dogs With Protein-Losing Enteropathy

Abstract

Background: Diagnosis of protein loss into the gastrointestinal tract using noninvasive techniques is challenging. In people, scintigraphy not only is a sensitive tool to confirm protein-losing enteropathy (PLE), but it also allows for localization of protein loss.

Hypothesis/objectives: To investigate the feasibility of ^99m Tc-labeled human serum albumin (HSA) scintigraphy in dogs with PLE in comparison with control dogs.

Animals: A total of 8 clinically healthy control research dogs and 7 client-owned dogs with gastrointestinal clinical signs and hypoalbuminemia (serum albumin concentration <2.0 g/dL).

Methods: Prospective case-control study. After IV injection of 400 MBq freshly prepared ^99m Tc HSA (30 mg/dog), images of the abdomen were obtained 10, 60, 120, and 240 minutes postinjection. Additional images of the salivary and thyroid glands were obtained to rule out free ^99m Tc. A scan was considered positive for PLE when radiopharmaceutical exudation was detectable in the intestinal tract.

Results: Only 1 control dog showed exudation of the radiopharmaceutical into the intestinal tract. No free ^99m Tc was detected in any dog. In dogs with PLE, focal small intestinal and diffuse small intestinal radiopharmaceutical exudation into the bowel was detected in 2 and 3 dogs, respectively, whereas in 2 dogs, there was disagreement about whether radiopharmaceutical exudation was focal or diffuse.

Conclusion and clinical importance: ^99m Tc-labeled HSA scintigraphy was feasible to diagnose PLE in dogs.

Keywords: Canine; Chronic enteric disease; Diagnostic imaging; Enteral protein loss; Nuclear medicine.