Computed tomographic reference ranges of intrathoracic caudal vena cava ratios in sedated adult dogs without cardiac, pulmonary, or hypovolemic disease.

BACKGROUND: Radiographic assessment of the intrathoracic caudal vena cava (CVC) is commonly used to evaluate hemodynamic status in veterinary patients without and with pulmonary, pericardial, or right-sided cardiac diseases. Many of these patients are now commonly evaluated with computed tomography (CT) in both emergency and referral settings. Traditional radiographic ratios in dogs, particularly the CVC height/aorta height (CVC/Ao) ratio, are often extrapolated to CT in order to determine if the CVC is normal in size. OBJECTIVES: The first goal of this retrospective study was to create an objective measurement method to evaluate the size of the CVC via CT. The second goal was to report normal CVC ratio values in both sagittal and transverse CT images. METHODS: The traditional lateral radiographic CVC ratios were extrapolated to similar ratios obtained from sagittal CT images in stable, sedated adult canine patients without known cardiac or pulmonary disease. Additionally, new methods of canine CVC ratios using transverse CT images were defined using vessel height and area. Mean, standard deviation, and 95% confidence intervals (CIs) of the CVC ratios in transverse and sagittal CT images were calculated to determine normal reference ranges. RESULTS: Ratio agreement from observers of different skill levels was moderate to excellent. Sagittal CT CVC/Ao mean was 1.07 ± 0.17 with a CI of 0.71.42. The mean and CI of transverse CT CVC/Ao height and area were 1.14 ± 0.27 and 0.781.44 and 1.36 ± 0.59 and 0.641.94, respectively. CONCLUSIONS: Application of normal sagittal and transverse CT ratio values in canine patients with and without hypotension, pulmonary, pericardial, or right-sided cardiac diseases is necessary to determine the clinical usefulness of these ratios.

Correlation between computed tomography and histological evaluation of nodal metastasis in dogs with mast cell tumours.

Early diagnosis of nodal metastasis has been shown to impact prognosis for dogs with mast cell tumours (MCT). The objective of this retrospective study was to determine the correlation between computed tomographic characteristics of lymph nodes and histologic nodal metastasis using the HN classification system, in dogs with cutaneous or subcutaneous MCT and regional lymph node(s) removal. Dogs that had removal of MCT and regional lymphadenectomy within 31 days of the initial staging computed tomography (CT) were enrolled. Subjective lymph node characteristics used included margination, loss of fat at hilus, shape of margin, perinodal fat pattern, increase in number of nodes, and pre- and post-contrast heterogeneity. Enhancement, heterogeneity, and short-long axis ratio were calculated. Seventy-one lymph nodes from 37 dogs were included. Generalised linear mixed model of assessment of lymph node was performed twice, with binary outcome [non-metastatic (HN0/1) versus metastatic (HN2/3)] and 4-point scales (HN0-HN3). After blind assessment of 7 characteristics described above, a final subjective interpretation of each lymph node as non-metastatic or metastatic was assigned. A significant correlation was found between final interpretation and prediction of metastasis. Higher HN classification was also significantly correlated with the increased number of nodes and pre- and post-contrast heterogeneity. No correlation was found in short-long axis ratio, calculated heterogeneity, or degree of enhancement. Sensitivity of CT was 35.7%, specificity was 96.6%, and accuracy was 60.5% for nodal metastasis. CT alone cannot be recommended for assessment of metastasis. The use of multiple computed tomographic characteristics may increase accuracy of nodal metastasis detection.

Accelerating cryoprotectant delivery using vacuum infiltration.

The ability to cryopreserve bone marrow within the vertebral body (VB) would offer significant clinical and research benefits. However, cryopreservation of large structures, such as VBs, is challenging due to mass transport limitations that prevent the effective delivery of cryoprotectants into the tissue. To overcome this challenge, we examined the potential of vacuum infiltration, along with carbonation, to increase the penetration of cryoprotectants. In particular, we hypothesized that initial exposure to high-pressure carbon dioxide gas would introduce bubbles into the tissue and that subsequent vacuum cycling would cause expansion and contraction of the bubbles, thus enhancing the transport of cryoprotectant into the tissue. Experiments were carried out using colored dye and agarose gel as a model revealing that carbonation and vacuum cycling result in a 14% increase in dye penetration compared to the atmospheric controls. Experiments were also carried out by exposing VBs isolated from human vertebrae to 40% (v/v) DMSO solution. CT imaging showed the presence of gas bubbles within the tissue pores for carbonated VBs as well as control VBs. Vacuum cycling reduced the bubble volume by more than 50%, most likely resulting in replacement of this volume with DMSO solution. However, we were unable to detect a statistically significant increase in DMSO concentration within the VBs using CT imaging. This research suggests that there may be a modest benefit to carbonation and vacuum cycling for introduction of cryoprotectants into larger structures, like VBs.

Comparison of indirect computed tomographic lymphography and near-infrared fluorescence sentinel lymph node mapping for integumentary canine mast cell tumors.

OBJECTIVE: To compare the independent and combined use of indirect computed tomographic lymphography (ICTL) and near-infrared fluorescence (NIRF) for sentinel lymph node (SLN) mapping in dogs with integumentary mast cell tumors (MCT) and report the metastatic LN rate. STUDY DESIGN: Prospective clinical study. ANIMALS: Twenty client-owned dogs. METHODS: Dogs underwent preoperative ICTL, then intraoperative NIRF SLN mapping and excision of the anatomic lymph node (ALN) and/or SLN, and primary MCT. Technique agreement was complete if the same SLN was detected, and partial if the same SLN was detected along with additional SLN. No agreement occurred if the techniques detected different or no SLN. MCT were graded using two- and three-tier schemes, and LN were graded from HN0-3; HN2-3 were considered metastatic. RESULTS: Complete, partial, and no agreement between ICTL and NIRF was seen in 8/20 (40%), 8/20 (40%), and 4/20 (20%) dogs, respectively. Detection of ICTL-SLN and NIRF-SLN failed in 1/20 (5%) and 4/20 (20%), respectively. Tumors were grade II/low-grade in 19/20 (95%) and grade III/high-grade in 1/20 (5%) dogs. Nineteen out of 20 (95%) dogs had HN2-3 LN. CONCLUSIONS: Technique agreement of at least one SLN was seen in 16/20 (80%) dogs. Although most MCT were classified as intermediate to low grade, LN metastases were commonly detected. CLINICAL SIGNIFICANCE: Combining ICTL and NIRF for MCT SLN mapping yields high SLN detection rates. Lymph node metastasis may be more common than previously reported for intermediate to low grade MCT.

Computed tomographic diagnosis of necroulcerative reticulorumenitis with portal venous gas in a lamb.

A 2-month-old, intact male Merino sheep was presented for acute inappetence and pyrexia. Contrast-enhanced abdominal computed tomography identified reticulorumenal intramural gas with suspected ruminal ulceration, arborizing portal venous gas, and mild peritoneal fluid. The lamb was treated medically for presumptive ulcerative reticulorumenitis and non-septic peritonitis. Over 10 days, the lamb initially showed mild improvement before clinical deterioration and was ultimately euthanized. Definitive diagnosis of necrotizing, ulcerative reticulorumenitis was made via necropsy with histopathology. An underlying cause was not determined. Key clinical message: Contrast-enhanced computed tomography was effective in identifying gastric emphysema and portal venous gas associated with reticuloruminal ulceration.

Diagnostic par tomodensitométrie d'une réticulo-ruménite nécro-ulcérative avec gaz veineux porte chez un agneau. Un mouton mérinos mâle intact, âgé de 2 mois, a été présenté pour une inappétence aiguë et une pyrexie. La tomodensitométrie abdominale de contraste augmentée a identifié du gaz intramural réticuloruménal avec une ulcération ruminale suspectée, du gaz veineux porte arborescent et un léger liquide péritonéal. L'agneau a été traité médicalement pour une réticulo-ruménite ulcéreuse présumée et une péritonite non-septique. Sur une période de 10 jours, l'agneau a d'abord montré une légère amélioration avant une détérioration clinique et a finalement été euthanasié. Le diagnostic définitif de réticulo-ruménite ulcéreuse nécrosante a été posé suite à la nécropsie et l'histopathologie. Une cause sous-jacente n'a pas été déterminée.Message clinique clé:La tomodensitométrie assistée par contraste s'est avérée efficace pour identifier l'emphysème gastrique et le gaz veineux porte associés à l'ulcération réticulo-ruminale.(Traduit par Dr Serge Messier).

Experience level as a predictor of entry into the hypotympanum during feline total ear canal ablation and lateral bulla osteotomy.

OBJECTIVES: The study hypotheses were as follows: (1) owing to the unique anatomy of the feline middle ear, the hypotympanum would be entered in less than 100% of cats during total ear canal ablation and lateral bulla osteotomies (TECA-LBOs); and (2) incomplete penetration of the septum and subsequent failure to enter the hypotympanum is more likely to occur in surgeries performed by a novice surgeon when compared with an experienced surgeon and may be under-recognized. METHODS: Head CT was performed in 12 feline cadavers to confirm absence of gross ear disease. A novice surgeon and an experienced surgeon were randomly assigned to perform TECA-LBO on the left or right ear. Surgeons were blinded to each other's surgical technique. CT of cadavers was performed after the procedure. Successful penetration of the septum, entry into the hypotympanic cavity and amount of bone removed in bulla osteotomy, quantified via CT, were compared between the novice surgeon and experienced surgeon. RESULTS: The novice surgeon entered the hypotympanum in 3/12 (25%) procedures, compared with 9/12 (75%) procedures performed by the experienced surgeon. The experienced surgeon performed a larger osteotomy than the novice surgeon (3301 mm vs 1376 mm, P <0.0023). Regardless of surgeon experience, more bone was removed in surgeries in which the hypotympanum was entered. CONCLUSIONS AND RELEVANCE: Our results underscore the need for familiarity with feline middle ear anatomy when performing TECA-LBOs. Postoperative CT is recommended for novice surgeons to confirm entry into the hypotympanum.

Description of a rare osteochondrosis lesion of the medial aspect of the distal intermediate ridge of the tibia in seven Thoroughbred horses (2008-2018).

Osteochondritis dissecans (OCD) of the distal intermediate ridge of the tibia (DIRT) is commonly identified on either the lateral to medial (LM) or dorso45°medial-plantarolateral oblique (D45M-PLO) projection of the tarsus. This manuscript describes a retrospective case series out of Hagyard Equine Medical Institute, for which medical records and radiographic projections of the tarsus were reviewed, consistent with Keeneland's repository requirements. This original investigation identified seven yearling Thoroughbred horses between 2008 and 2018 with radiographic signs of atypical osteochondrosis lesions within the tarsus. The atypical lesions, originating along the medial margin of the distal intermediate ridge of the tibia, were initially only diagnosed on the dorso10°lateral-plantaromedial (D10L-PMO) projection and were overlooked on the LM and D45M-PLO views. Following the diagnosis of osteochondrosis in these seven cases, the radiographs were reviewed and re-evaluated, but osteochondrosis and/or fragmentation could not be definitively diagnosed on the LM and/or D45M-PLO projections alone. Our findings highlight the importance of a complete radiographic study of the equine tarsus when screening horses for OCD lesions of the distal intermediate ridge of the tibia and that atypical DIRT lesions may go undetected if the D10L-PMO projection is not performed.