Morphology of the Canine Omentum Part 1: Arterial Landmarks that Define the Omentum

Computed tomography of suppurative and neoplastic diseases involving the canine omenta and omental bursa

The greater and lesser omenta are fused peritoneal folds that largely delimit the omental bursa (lesser peritoneal cavity). The omental bursa is a potential space within the abdominal cavity that communicates with the greater peritoneal cavity via the omental (epiploic) foramen: it is subdivided into the omental vestibule, caudal omental recess, and splenic recess. Aims of this retrospective case series study were to describe the frequencies of CT findings of dogs with confirmed inflammatory or neoplastic disease of the omenta, omental bursa, or both. The sample included seven adult, medium-to-large breed dogs. All had fluid in the greater peritoneal cavity and 5/7 (71%) dogs also had fluid in the omental bursa. Primary suppurative inflammatory disease was present in three dogs, each dog had a large abscess with central gas in either the omental vestibule (two dogs) or caudal omental recess (one dog). Both abscesses in the omental vestibule arose from the papillary process of the caudate liver lobe and were surgically removed without complication. Neoplasia was present in four dogs and either arose from omentum (hemangiosarcoma, carcinoma) or infiltrated the omentum from an adjacent organ (splenic leiomyosarcoma, gastric adenocarcinoma). Neoplasms created mass-like tumors, infiltrative tumors, or both and had variable distribution (focal, multifocal, or locally extensive). All dogs with neoplasia were euthanized. CT signs of inflammatory and neoplastic disease overlapped, but the presence of gas might prioritize abscessation. CT signs helped decide feasibility of surgery based on extent of local invasion, especially involvement of structures passing through the porta hepatis.

CT imaging features of fat stranding in cats and dogs with abdominal disorder

BACKGROUND

Fat stranding is a non-specific finding of an increased fat attenuation on computed tomography (CT) images. Fat stranding is used for detecting the underlying lesion in humans.

OBJECTIVES

To assess the clinical significance of fat stranding on CT images for identifying the underlying cause in dogs and cats.

METHODS

In this retrospective study, the incidence, location, extent, distribution, and pattern of fat stranding were assessed on CT studies obtained from 134 cases.

RESULTS

Fat stranding was found in 38% (51/134) of all cases and in 35% (37/107) of tumors, which was significantly higher in malignant tumors (44%) than benign tumors (12%). Moreover, fat stranding was found in more than two areas in malignant tumors (16/33) and in a single area in benign tumors (4/4). In inflammation, fat stranding was demonstrated in 54% (7/13) in a single area (7/7) as a focal distribution (6/7). In trauma, fat stranding was revealed in 50% (7/14) and most were in multiple areas (6/7). Regardless of the etiologies, fat stranding was always around the underlying lesion and a reticular pattern was the most common presentation. Logistic regression analysis revealed that multiple areas (p = 0.040) of fat stranding and a reticulonodular pattern (p = 0.022) are the significant predictors of malignant tumor.

CONCLUSIONS

These findings indicated that CT fat stranding can be used as a clue for identifying the underlying lesion and can be useful for narrowing the differential list based on the extent and pattern.

Morphological investigation of canine epigastric organs and adjacent structures via computed tomography, ultrasound and anatomical prosection

The canine epigastric organs, their locations and visualization of these components are essential for veterinary practice and anatomical research. Despite their importance, conflicts and discrepancies in the published material, to date, still exist, even in a species that has been studied extensively. The aim of this research was to undertake computed tomography, and anatomical sections from differing views and levels in addition to the ultrasound appearance of the main organs of the epigastria region. The epigastric organs, and associated anatomical features and landmarks that affected by stomach fullness were described in relation to their relative positions, visual appearance and general anatomy for both empty and filled stomachs. These features were not only described, but also compared against the published literature.

Gastric lymphatic flows may change before and after endoscopic submucosal dissection: in vivo porcine survival models

BACKGROUND AND STUDY AIM

Standard gastrectomy with lymphadenectomy is recommended following endoscopic submucosal dissection (ESD) due to the risk of lymph-node metastasis for resected cancers. However, when lymphatic flows remain unchanged after ESD, a minimally invasive function-preserving surgery based on the sentinel node (SN) concept may be applicable. In this study, using porcine survival models, we aimed to investigate whether gastric lymphatic flows were modified following ESD.

METHODS

Twelve pigs, each with one simulating lesion 3 cm in size, were used. Indocyanine green (ICG) fluid was endoscopically injected into the submucosa in four quadrants surrounding the lesion. Following laparoscopic observation of lymphatic flows, the lesions were resected by ESD. After 4 weeks, ICG fluid was injected in four quadrants surrounding the scar and lymphatic flows were observed in the same manner as the initial procedure. The distribution of lymphatic flows, including stained SNs, was compared.

RESULTS

In ten lesions (83.3%), the distribution of flows remained unchanged. However, in one lesion, the flow along the right gastric epiploic artery (R-GEA) disappeared on the lesser curvature of the middle stomach. In addition, in one lesion, the flow along R-GEA emerged on the lesser curvature of the lower stomach.

CONCLUSIONS

Our study revealed that, despite ESD, lymphatic flows remained unchanged in most parts of the stomach. The SN concept may be applied after ESD, except for lesions on the lesser curvature. However, in the case of the lesser curvature, special care must be given to the SN concept.

The Omental Pedicle Flap in Dogs Revised and Refined: A Cadaver Study

OBJECTIVE

To expand current knowledge on the canine omental vasculature and refine the existing lengthening technique of the canine omentum.

STUDY DESIGN

Ex vivo study.

ANIMALS

Canine cadavers (n=20).

METHODS

In 10 canine cadavers the omental arteries were mapped using intravascular latex injection and these results were used to create an omental pedicle flap based on the splenic artery in 10 additional cadavers. The operating range of the flap was recorded with particular attention to the main regions of interest for omental transposition in dogs (axillary and inguinal regions).

RESULTS

The superficial and deep omental leaves were each predominantly supplied by a left and a right marginal omental artery that anastomosed near the caudal omental border into a superficial and a deep omental arch, respectively. Anastomoses between arteries of the superficial and the deep omental leaves were weak and inconsistent, except for 1 anastomosis that was found in 8 of 10 dogs. By transposing the intact omentum, the right axilla could be reached in 3 dogs, both axillae in 1 dog, and both groins in all cadavers. In all cases, the omental pedicle reached to and beyond the axillary and inguinal regions. By unfolding the pedicle leaves, the width of the pedicle tip could be doubled.

CONCLUSION

When lengthening the omentum is necessary to reach extra-abdominal structures, the omental pedicle flap based on the splenic artery appears to preserve the omental vascular supply. These observations warrant further clinical trials to evaluate this new omtental flap technique in vivo.