Improving Conspicuity of the Canine Gastrointestinal Wall Using Dual Phase Contrast‐enhanced Computed Tomography: A Retrospective Cross‐sectional Study

Abstract

Gastrointestinal (GI) disease is a common clinical complaint in small animal patients; computed tomography (CT) examinations enable a global overview of the GI tract and associated structures. Previously, the GI wall has been reportedly identified from serosa to mucosa in 77% of standard postcontrast CT studies and wall layers seen in ultrasound have not been distinguished. Inconsistent strong contrast enhancement of the inner layer of the GI mucosal surface was noted on dual phase CT studies acquired in our institution, which increased the visibility of the GI tract and disease processes. The aim of this retrospective, observational, cross-sectional study was to determine the optimal portal vein attenuation for maximizing GI wall conspicuity using dual phase contrast-enhanced CT. Patients with abdominal CT for a non-GI related disease were included. In a pilot study, 175 GI segments from 35 CT studies were graded for presence of mucosal surface enhancement (MSE). The strongest mucosal surface enhancement grade correlated with portal vein attenuation of 43-150 HU; this value was used as inclusion criterion in the main study. A total of 441 GI segments were evaluated in 42 CT studies postcontrast for GI wall conspicuity. The GI wall was conspicuous in 56.7% precontrast, 84.5% at 30s, and 77.3% late postcontrast; 4.7% of segments were removed due to motion blur. At 30 s distinct mucosal surface enhancement was seen in the small intestine and gastric mucosal surface enhancement was poor. Findings supported the use of dual phase contrast-enhanced CT for improving conspicuity of the GI wall.

Contrast‐enhanced computed tomography may be helpful for characterizing and staging canine gastric tumors

“…The normal gastric wall is histologically classified as four slices: mucosa, submucosa, muscular layer, and serosa . Computed tomography makes it possible to identify the layer structure of the gastric wall after contrast material injection . The inner layer with high attenuation corresponds to the mucosa layer in the delayed‐phase.…”

“…Adenocarcinomas and inflammatory polyps are epithelial in origin . In humans, the mucosa layer displays high attenuation in the postcontrast images, and attenuation in such images may be influenced by the origin of the gastric tumor. Enhancement patterns are closely related to blood supply and histologic characteristics, such as the presence of inflammatory or bland spindle cells admixed within edematous, myxoid, and loose collagenous stroma, blood vessels, perivascular fibroblastic proliferation, and hyalinization .…”

“…26 Computed tomography makes it possible to identify the layer structure of the gastric wall after contrast material injection. 29 The inner layer with high attenuation corresponds to the mucosa layer in the delayed-phase. influenced by the involved area of the lymphoma.…”

Preliminary study of CT features of intermediate- and high-grade alimentary lymphoma and adenocarcinoma in cats

“…On contrast CT, the mucosal layer of a normal intestinal wall displays high attenuation in animals with early phase. 24 In the delayed phase, there is a washout of contrast in the mucosa and prolonged homogeneous enhancement of the outer intestinal wall. 24 Adenocarcinoma originates from the glandular epithelium in the crypts of Lieberkühn and spreads via the intramural or submucosal lymphatics.…”

CT findings in five dogs with surgically confirmed colonic torsion

“…Displacement of the cecum and ascending colon, the transverse colon and the descending colon, was defined as the presence of these structures in an abnormal location . Enhancement of the colonic wall following contrast administration was assessed subjectively as compared with that of the ileum . The presence of pneumatosis coli was defined as visualization of gas within the wall of the colon .…”