Feline abdominal ultrasonography: What’s normal? What’s abnormal? The diseased gastrointestinal tract

Abstract

Practical relevance: Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. B-mode ultrasonography is likely the most widely used modality for imaging the gastrointestinal (GI) tract in cats and it can help in the diagnosis of GI masses, foreign bodies and disorders of the ileocaecocolic junction. Clinical challenges: Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even differentiating between normal variations and pathological changes can be challenging for all but the most experienced. For example, while for inflammatory conditions of the feline GI tract changes are frequently identified on ultrasound, there may occasionally be no changes to the appearance of the intestine; hence a ‘normal’ ultrasound does not exclude the possibility of inflammatory disease. Aim: This review, part of an occasional series on feline abdominal ultrasonography, describes the appearance of a range of conditions that affect the feline GI tract; the normal GI tract is addressed in an accompanying article in this issue of JFMS. Aimed at general practitioners who wish to improve their knowledge and confidence in feline abdominal ultrasound, this review is accompanied by high-resolution images and videos available online as supplementary material. Equipment: Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience. Evidence base: Information provided in this article is drawn from the published literature and the author’s own clinical experience.

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

“…Concerning B-mode qualitative values, there were no statistically significant differences in terms of layer definition, localization, and echogenicity between these three groups, but only if compared to HGAL. These results agree with the literature for US findings in inflammatory and neoplastic disease of the small intestine both in dogs and cats [ 5 , 8 , 9 , 11 , 12 , 38 , 43 , 44 ]. These results indicate that, even for gastric involvement, inflammatory and low-grade lymphomatous infiltrates have similar US features, which are indistinguishable without an adequate histological or immunohistochemical characterization.…”

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

“…Lymphoma is the most common GI-related malignancy in the cat, representing 30% of all feline neoplasms; moreover, 70% of cats with lymphoma have GI involvement: In this species, the small intestine is the most commonly affected site and is also the most frequent tumour of the gastric wall (Willard, 2012;Paulin et al, 2018). The Siamese breed and the older age (between 10 and 14 years in particular) are correlated to an increased risk (Griffin, 2019). Lymphoma is less common in dogs than in cats; furthermore, Alimentary Lymphoma (AL) represents only 7% of all canine lymphoma (Gieger, 2011).…”

Diagnosing and treating chronic vomiting in cats

“…With primary gastrointestinal disease, ultrasonographic changes commonly include changes in the thickness of the wall and potentially loss of layering. Loss of layering of the GI tract is most commonly associated with neoplasia; however, it can occasionally be seen in cats with severe inflammatory disease (Griffin 2019c).…”

“…Lymphoma can present as solitary or multiple intestinal masses (these are most often transmural, hypoechoic, circumferential thickenings of the GI wall, associated with loss of normal wall layering), or as a diffuse thickening of the small intestinal muscularis layer with otherwise normal wall layering (Griffin 2019c). A previous study has identified a significant increased thickness of the intestinal wall and muscularis propria layer in the small intestines of cats with GI small cell T‐cell lymphoma and IBD.…”