Computed tomography may detect liver infiltration of canine diffuse hepatic lymphoma.

BACKGROUND: In dogs, hepatic lymphoma is characterized by neoplastic lymphocyte infiltration into the liver. Reports on the computed tomography (CT) findings of the liver for canine hepatic lymphoma are few, with only one study of multiple liver lesions type. OBJECTIVES: The purpose of this study was to retrospectively assess the CT findings of the liver in canine diffuse hepatic lymphoma. METHODS: As control, five dogs without abnormalities in the liver were included. CT data were analysed, and the following were noted: presence of edge bluntness of the liver, presence of periportal collar sign, the liver size:body weight (BW) ratio and the mean attenuation of liver lesions on pre-contrast, arterial-phase, portal-phase and equilibrium-phase post-contrast images. RESULTS: On CT examination, edge bluntness of the liver was significantly detected in lymphoma (4/5, 80%), as opposed to the control (0/5, 0%) (p = 0.048, φ = 0.82). The periportal collar sign was detected in lymphoma (3/5, 60%), as opposed to the control (0/5, 0%) (p = 0.17, φ = 0.65). The liver size:BW ratio of lymphoma cases was significantly higher compared to that of the control cases (p = 0.0002, r = 0.92). The mean Hounsfield unit of lymphoma cases in the pre-contrast, arterial-phase, portal-phase and equilibrium-phase images were significantly lower than in the control cases (p = 0.005, r = 0.81; p = 0.0003, r = 0.91; p = 0.01, r = 0.75 and p = 0.02, r = 0.71, respectively). CONCLUSIONS: Hepatic lymphoma should be a differential for a blunted and enlarged liver with hypoattenuation on CT examination.

MRI findings, including diffusion-weighted imaging, in seven cats with nasal lymphoma and two cats with nasal adenocarcinoma.

OBJECTIVES: Primary nasal tumours in cats are rare, with lymphoma being the most common feline nasal tumour, followed by adenocarcinoma. Although CT can reliably detect feline nasal tumours, there are no specific CT features that identify each tumour type. To our knowledge, there have been no reports describing MRI findings, including diffusion-weighted imaging (DWI), for nasal lymphomas and adenocarcinomas in cats. Therefore, this retrospective study aimed to evaluate the MRI findings of nasal lymphoma and adenocarcinoma, including qualitative and quantitative analysis of DWI. METHODS: MRI examination was performed on seven cats with histologically confirmed lymphoma and on two with adenocarcinoma. The MRI protocol included T2-weighted imaging (T2WI), T1-weighted imaging (T1WI) and DWI. Apparent diffusion coefficient (ADC) values were measured using DWI. Contrast agent was not used in one cat with lymphoma. RESULTS: Of the cats with lymphoma, three (43%) were iso- and hyperintense on T2WI, seven (100%) were isointense on T1WI, five (83%) exhibited mild heterogeneous enhancement, including a prominent region of non-enhancement on post-contrast T1WI, and seven (100%) cats exhibited hyperintensity on DWI. The median ADC values were 0.45 × 10-3 mm2/s (range 0.37-0.53 × 10-3 mm2/s). For adenocarcinoma, two (100%) were iso- and hyperintense on T2WI, two (100%) were isointense on T1WI, two (100%) exhibited marked heterogeneous enhancement on post-contrast T1WI and two (100%) were isointense on DWI. The median ADC values were 1.08 × 10-3 mm2/s (range 0.88-1.27 × 10-3 mm2/s). The median ADC values of lymphoma tended to be lower than adenocarcinoma (P = 0.056). CONCLUSIONS AND RELEVANCE: Determining ADC value and tumours with a large area of non-enhancement may be helpful in differentiating nasal lymphoma from nasal adenocarcinoma.

Impaired bone quality characterized by apatite orientation under stress shielding following fixing of a fracture of the radius with a 3D printed Ti-6Al-4V custom-made bone plate in dogs.

Custom-made implants have recently gained attention in veterinary medicine because of their ability to properly fit animal bones having a wide variety of shapes and sizes. The effect of custom-made implants on bone soundness and the regeneration process is not yet clear. We fabricated a 3D printed Ti-6Al-4V custom-made bone plate that fits the shape of the dog radius, and placed it into the radius where an osteotomy had been made. The preferential orientation of the apatite c-axis contributes to the mechanical integrity of the bone and is a reliable measure of bone quality. We determined this parameter as well as the bone shape and bone mineral density (BMD). The bone portion which lies parallel to the bone plate exhibited bone resorption, decreased BMD, and significant degradation of apatite orientation, relative to the portion outside the plate, at 7 months after the operation. This demonstrates the presence of stress shielding in which applied stress is not transmitted to bone due to the insertion of a stiff bone plate. This reduced stress condition clearly influences the bone regeneration process. The apatite orientation in the regenerated site remained different even after 7 months of regeneration, indicating insufficient mechanical function in the regenerated portion. This is the first study in which the apatite orientation and BMD of the radius were evaluated under conditions of stress shielding in dogs. Our results suggest that assessment of bone repair by radiography can indicate the degree of restoration of BMD, but not the apatite orientation.

Less enhancement and low apparent diffusion coefficient value on magnetic resonance imaging may be helpful to detect canine prostate adenocarcinoma in case series.

In dogs, diagnosis of prostate cancer is often delayed because clinical signs are not pathognomonic. Although ultrasonography is mainly performed to detect prostate cancer, the ultrasonographic appearance is not specific. In humans, magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI) is used to localize the prostate tumour. To our knowledge, there are no studies of MRI findings for detecting or localizing prostate cancer. The purpose of this study was to assess MRI findings of prostate cancer. As a control, three prostate hyperplasia cases were included. MRI data were analysed, and the following parameters were noted: signal intensity (SI) of prostate lesion on T2-weighted imaging, T1-weighted imaging and DWI, enhancement pattern of prostate lesion, and relative contrast enhancement indices (RCEI) and apparent diffusion coefficient (ADC) value of prostate lesion. For MRI examination, the mean RCEI of the adenocarcinoma was significantly lower than that of hyperplasia (P = .01, r = .8). The SI of the DWI of adenocarcinoma was significantly higher compared to hyperplasia (P = .03, φ = 1). The mean ADC values of the adenocarcinoma were significantly lower than that of hyperplasia (P = .03, r = .82). Thus, less enhancement on MRI, and low ADC value on MRI may help to detect prostate adenocarcinoma.

Urinary bladder reconstruction using autologous collagenous connective tissue membrane "Biosheet®" induced by in-body tissue architecture: A pilot study.

INTRODUCTION: In-body tissue architecture (iBTA) technology, based on cell-free tissue engineering, can produces collagenous tissues for implantation by subcutaneous embedding a designed mold. The aim of this study was to evaluate the biocompatibility of iBTA-induced "Biosheet®" collagenous sheets, as scaffold materials for bladder reconstruction. METHODS: Canine Biosheet® implants were prepared by embedding molds into subcutaneous pouches in beagles for 8 weeks. A part of canine bladder wall was excised (2 × 2 cm) and repaired by patching the same sized autologous Biosheet®. The Biosheet® implants were harvested 4 weeks (n = 1) and 12 weeks (n = 3) after the implantation and evaluated histologically. RESULTS: No disruption of the patched Biosheet® implants or urinary leakage into the peritoneal cavity was observed during the entire observation periods. There were no signs of chronic inflammation or Biosheet® rejection. The urine-contacting surface of luminal surface of the Biosheet® was covered with a multicellular layer of urothelium cells 4 weeks after implantation. α-SMA-positive muscle cells were observed at the margin of the Biosheet® implants at 12 weeks after the implantation. In addition, in the center of the Biosheet® implants, the formation of microvessels stained as α-SMA-positive was observed. CONCLUSION: Biosheet® implants have biocompatibility as a scaffold for bladder reconstruction, indicating that they may be applicable for full-thickness bladder wall substitution. Further studies are required for definitive evaluation as a scaffold for bladder reconstruction.

Contrast-enhanced computed tomography findings of canine primary renal tumors including renal cell carcinoma, lymphoma, and hemangiosarcoma.

In veterinary medicine, abdominal ultrasonography is used to rank the differential diagnosis of renal lesions. However, a conventional sonographic examination may show nonspecific findings. The purpose of this study was to assess the computed tomography (CT) findings of canine renal tumors, including renal cell carcinoma (RCC), lymphoma, and hemangiosarcoma (HSA). In this retrospective study, the following CT parameters were recorded for each dog: 1) extent of renal involvement of tumors, 2) enhancement pattern, 3) number of renal tumors, 4) renal tumor vessel enhancement in the corticomedullary phase, 5) presence of lymphadenopathy and lung metastasis, and 6) attenuation values of the renal tumors on the pre- and post-contrast corticomedullary, nephrographic, and excretory phase images. Fifteen dogs met the inclusion criteria, of which nine had RCCs, four had lymphomas, and two had HSAs. RCCs tended to show heterogeneous enhancement and unilateral renal involvement, and vessel enhancement was detected in the corticomedullary phase in dogs with RCC. Conversely, renal lymphomas showed homogeneous enhancement, bilateral renal involvement, and multiple masses; in these dogs, no vessel enhancement was detected in the corticomedullary phase, and the incidence of lymphadenopathy was low. However, in dogs with lymphadenopathy, the renal lymphoma was associated with regionally severe lymphadenopathy. Finally, renal HSAs tended to show heterogeneous enhancement with a non-enhanced area and unilateral renal involvement; in these dogs, vessel enhancement was detected in the nephrographic phase, with the enhancement expanding around the vessel. These findings had no significant differences. Further studies with a larger sample size are required to examine the association between CT and histopathological findings.