Diagnostic Imaging of Gastrointestinal Tumours in Dogs and Cats: A Review

Abstract

Gastrointestinal tract tumours in dogs and cats are characterized by non-specific clinical presentation and laboratory abnormalities, but require fast identification, characterization and staging. Imaging techniques play a key role in the diagnostic process of these diseases in routine veterinary practice. Survey and contrast radiography may indicate primary or secondary signs of gastric or intestinal neoplasia such as a wall mass, functional alterations and stenosis points, but they have low sensibility and limited diagnostic value. Ultrasound allows to perform a detailed study of gastrointestinal wall's layers and thickness and adjacent organs but requires adequate acoustic windows and expert operators. Computed tomography is a reference technique both in human and veterinary oncology for the identification of primary neoplasms and for metastases searching thanks to the possibility to scan the whole body and the use of intravenous iodinated contrast medium for vascular assessment. Specific intraluminal distension techniques such as Helical-Hydro Computed Tomography and Computed Tomography Colonography can improve respectively stomach and colon associated masses. To date, Endoscopic Ultrasonography and Magnetic Resonance, despite their proven value in human medicine, lack of literatures that support their usefulness in the diagnosis and staging of gastrointestinal neoplasms in veterinary medicine and are not widely used in these pathologies. The purpose of this work is to review the literature on imaging modalities applied in gastrointestinal tumours diagnosis in dogs and cats, highlighting advantages and limitations of each technique in order to choose the proper imaging procedure in everyday clinical practice.

B-Mode and Contrast Enhanced Ultrasonography Features of Gastric Inflammatory and Neoplastic Diseases in Cats

“…In our study, the average gastric interrugal thickness in healthy cats (mean 2.6 mm) was similar to that reported in the literature (around 2 mm) [ 1 , 40 ]. Focal or diffuse wall thickening with various echogenicity, associated with a loss of layer definition, are the main signs of HGAL [ 5 , 6 , 7 , 8 , 10 , 41 , 42 ]. However, LGAL is reported to have a similar B-mode US appearance to that of GI inflammatory diseases, causing no alteration or diffuse/multifocal mild wall thickening with lost/reduced/preserved layer definition and mesenteric lymphadenopathy [ 5 , 11 , 12 , 38 ].…”

“…Gastric tumours are rare in cats and, among them, alimentary lymphoma (AL) is the most commonly reported in this species [ 1 , 2 , 3 , 4 , 5 , 6 ]. AL can involve the gastrointestinal (GI) tract focally, multifocally or diffusely with the variable involvement of extra-gastrointestinal sites [ 4 , 5 , 7 ].…”

“…Lymphoma can also show a focal hypoechoic eccentric mass [ 1 , 10 ]. However, US findings in the course of inflammatory diseases of the GI tract can be very similar to those of neoplastic infiltration: diffuse or multifocal mild wall thickening, loss of definition among wall layers and mesenteric lymphadenopathy [ 6 , 11 , 12 ]. Other non-neoplastic gastric lesions may have similar appearances to that of the wall’s neoplasia [ 13 ].…”

B-Mode and Contrast Enhanced Ultrasonography Features of Gastric Inflammatory and Neoplastic Diseases in Dogs

“…Gastric neoplasms are uncommon in dogs and represent less than 1% of all neoplastic lesions in this species [ 1 , 2 , 3 ]. Clinical presentation in dogs affected by these tumors may include non-specific progressive gastrointestinal signs like chronic vomiting, hematemesis, melena, anorexia, and weight loss [ 4 ].…”

Computed Tomography Evaluation of Normal Canine Abdominal Lymph Nodes: Retrospective Study of Size and Morphology According to Body Weight and Age in 45 Dogs

“…The visceral group is subdivided into subgroups that apply to specific organs: celiac, cranial, and caudal mesenteric [ 1 ]. For many of these lymph nodes, morphological characteristics have been described through ultrasonography, although food and gas in the gastrointestinal tract can often have negative effects on the response of small abdominal structures [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. There are studies for tracheobronchial, sternal, or cervical lymph nodes [ 11 , 12 , 13 , 14 , 15 ] that have instead proposed computed tomography (CT) as a modality of investigation, and recently, CT was also proposed for morphological and morphometric evaluation of normal abdominal lymph nodes (ALs) to reduce the limitations of ultrasound [ 16 ].…”