peer reviewed | [en] OBJECTIVE: Treatment of orofacial tumors in dogs is associated with high morbidity and reliable prognostic factors are lacking. Dynamic contrast-enhanced computed tomography (DCECT) can be used to assess tumor perfusion. The objectives of this study were to describe the perfusion parameters of different types of orofacial tumors and to describe the changes in perfusion parameters during radiotherapy (RT) in a subset of them. ANIMALS: 11 dogs with orofacial tumors prospectively recruited. CLINICAL PRESENTATION AND PROCEDURES: All dogs had baseline DCECT to assess blood volume (BV), blood flow (BF), and transit time (TT). Five dogs had repeat DCECT during megavoltage RT. RESULTS: 5 squamous cell carcinomas, 3 sarcomas, 1 melanoma, 1 histiocytic sarcoma, and 1 acanthomatous ameloblastoma were included. Blood volume and BF were higher in squamous cell carcinomas than in sarcomas, although no statistical analysis was performed. At repeat DCECT, 4 dogs showed a reduction in the size of their tumor during RT. Among these dogs, 3 showed an increase in BV and BF and 1 a decrease in these parameters between the baseline and the follow-up DCECT. The only dog whose tumor increased in size between the first and the second DCECT showed a decrease in BV and BF. CLINICAL RELEVANCE: Perfusion parameters derived from DCECT were described in a series of dogs with various types of orofacial tumors. The results suggest that epithelial tumors could have higher BV and BF than mesenchymal tumors, although larger sample sizes are needed to support these preliminary findings.

OBJECTIVE To determine corneal thickness of eyes of healthy goats, sheep, and alpacas by use of a portable spectral-domain optical coherence tomography (SD-OCT) device and evaluate intraoperator reliability for measurements. ANIMALS 11 female goats, 10 female sheep, and 11 (4 males and 7 females) alpacas. PROCEDURES Each animal was sedated, and gentle manual restraint was used to ensure proper positioning of the head and globe. Corneal pachymetry was performed (in triplicate) with a portable SD-OCT device on both eyes of each animal. All corneal measurements were obtained manually by use of the integrated caliper function. Corneal epithelial thickness (CET), corneal stromal thickness (CST), Descemet membrane thickness (DMT), and total corneal thickness (TCT) were measured twice on each image, and a mean value was calculated. RESULTS Mean ± SD values for CET, CST, DMT, and TCT were 96.1 ± 5.0 μm, 486.0 ± 10.3 μm, 36.8 ± 4.8 μm, and 616.9 ± 7.1 μm, respectively, for the goats; 111.6 ± 5.7 μm, 599.8 ± 10.0 μm, 31.0 ± 4.5 μm, and 741.1 ± 9.9 μm, respectively, for the sheep; and 147.4 ± 5.7 μm, 446.1 ± 7.4 μm, 44.5 ± 5.0 μm, and 634.8 ± 6.2 μm, respectively, for the alpacas. Intraclass correlations ranged from 0.49 to 0.83 for CET, CST, and TCT and from 0.13 to 0.36 for DMT. CONCLUSIONS AND CLINICAL RELEVANCE SD-OCT provided manual measurement of corneal thickness (CET, CST, and TCT) with clinically acceptable intraoperator reliability for eyes of healthy goats, sheep, and alpacas.

High-resolution computed tomography (HRCT) was performed in 21 isolated animal lungs, from 4 mammalian species (pigs, rabbits, dogs, sheep). Gross and subgross central and peripheral lung morphology was determined by HRCT. Three distinct types of lungs can be identified, principally based on the extent of interlobular septal development; the relationship of major vessels to airways; and the thickness of the visceral pleura. Type-I lung is found in pigs, sheep, and cattle; type-II lung is found in rabbits, dogs, cats, and monkeys; and type-III lung is found in human beings and horses. These mammalian lungs were compared with human lungs. The potential use of HRCT to investigate specific human lung diseases in the aforementioned species also was considered.

Objective—To evaluate the radiographic, computed tomographic (CT), and cadaveric anatomy of the head of boa constrictors. Animals—4 Boa constrictor imperator cadavers. Procedures—Cadavers weighed 3.4 to 5.6 kg and had a body length ranging from 189 to 221 cm. Radiographic and CT images were obtained with a high-detail screen-film combination, and conventional CT was performed with a slice thickness of 1.5 mm. Radiographic images were obtained in ventrodorsal, dorsoventral, and left and right laterolateral recumbency; CT images were obtained with the animals positioned in ventral recumbency directly laying on a plastic support. At the end of the radiographic and CT imaging session, 2 heads were sectioned following a stratigraphic approach; the other 2, carefully maintained in the same position on the plastic support, were moved into a freezer (-20°C) until completely frozen and then sectioned into 3-mm slices, respecting the imaging protocol. The frozen sections were cleaned and then photographed on each side. Anatomic structures were identified and labeled on gross anatomic images and on the corresponding CT or radiographic image with the aid of available literature. Results—Radiographic and CT images provided high detail for visualization of bony structures; soft tissues were not easily identified on radiographic and CT images. Conclusions and Clinical Relevance—Results provide an atlas of stratigraphic and cross-sectional gross anatomy and radiographic and CT anatomy of the heads of boa constrictors that might be useful in the interpretation of any imaging modality in this species.

The blood supply to the proximal sesamoid bone of the equine forelimb was examined in 18 cadaver limbs from adult horses, using x-ray computed tomography and a tissue-clearing (Spalteholz) technique. Results of the study indicated that the proximal sesamoid bones were supplied by multiple branches of the medial and lateral palmar digital arteries, which entered the proximal half of the bones on their nonarticular, abaxial surface. After entering the bone, the vessels traverse dorsally, axially, and distally, arborizing into several smaller branches that appear to supply the entire bone. The major branches of these vessels reside in bony canals, the orientation and distribution of which parallel the radiographic lucencies seen in horses with sesamoiditis and correspond to the configuration of apical fracture patterns.

Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were determined in 8 clinically normal neonatal foals. After the foals oriented themselves and nursed the mares, they were sedated as necessary, and local anesthesia was provided for making the skin incisions. Using a technique similar to that used in human beings, an indwelling subdural catheter was placed to measure ICP. Carotid artery catheterization was used to measure arterial blood pressure. Cerebral perfusion pressure was calculated as the difference between mean arterial blood pressure and ICP. Intracranial pressure and CPP readings were taken twice during each 24-hour period, starting at 6 hours of age and continuing through 72 hours of age. Mean (+/- SD) ICP were 5.83 +/- 1.82, 8.81 +/- 2.06, and 9.55 +/- 1.55 mm of Hg (range, 2 to 15 mm of Hg), and mean CPP were 80.19 +/- 10.34, 75.30 +/- 10.86, and 76.80 +/- 12.59 mm of Hg (range, 50 to 109 mm of Hg) for each of the first three 24-hour periods after birth, respectively. All 8 foals had physical and neurologic examinations, CSF analysis, and computerized axial tomography evaluations. The foals manifested normal behavior during the interval of measurements, and adverse effects of the procedure were not detected during the monitoring period. Establishment of normal values for TCP and CPP are important to clinicians who have the opportunity to apply this technique for monitoring and evaluating neonatal foals with signs of CNS dysfunction.

Quantitative computed tomography has been used extensively to measure bone mineral density; particularly in the vertebral column and in the proximal portion of the femur in human beings with osteoporosis. Other potential applications of this technique include evaluation of bone adjacent to metallic endoprostheses and evaluation of fractures as they heal. Unfortunately, metal causes severe image degradation, principally seen as starburst streaking. One method used to decrease these artifacts is by imaging less-attenuating materials, such as titanium alloy. Titanium decreases image degradation sufficiently to allow accurate determination of the geometric properties of cadaveric bone. In our study, the effect of a titanium segmental endoprosthesis on bone mineral density measurement was determined by use of bone specimens from dogs and calibration standards. Titanium decreased the bone mineral density of calibration solutions from 6.8 (500 mg/cm3) to 17.7% (250 mg/cm3), and increased bone mineral density of cortical bone by 5.3%. Titanium did not affect the repeatability of these scans, indicating that the error caused by titanium was systematic and can be corrected. Our data were suggestive that quantitative computed tomography can be used to measure bone mineral density of cortical bone adjacent to titanium endoprostheses, with a predictable increase in density measurement.

Nephrotomography and ultrasonography were used in 11 dogs with hyperadrenocorticism to assess the value of these techniques for the localization of biochemically diagnosed hyperfunctioning adrenocortical tumors. Both techniques enabled accurate localization of a unilateral adrenal mass in each of the dogs. Cross-sectional diameters of the masses ranged from 1 to 4 cm. In 1 dog, expansion of tumor into the caudal vena cava was revealed by caudal venacavography and ultrasonography. Mineralization in the tumor mass in 2 dogs was easily recognized by nephrotomography, but not by ultrasonography. Paracostal laparotomy confirmed the presence of an adrenocortical tumor in each dog, and expansion of tumor into the caudal vena cava in 1 dog. Cross-sectional diameters of the tumors ranged from 1.2 to 4.5 cm and corresponded well with cross-sectional measurements by nephrotomography and ultrasonography. It was concluded that nephrotomography and ultrasonography have similar diagnostic accuracies for the detection and localization of hyperfunctioning adrenocortical tumors.

Cutaneous lymphoma is rare in cats. An 11-year-old spayed female Persian cat presented with crust, ulceration, and multiple nodules on the shoulder and forelimb for 2 months. Computed tomography revealed a diffuse, irregularly margined lesion in the dorsal cutis extending from cervical to thoracic vertebrae. Cytological evaluation predominantly revealed large round cells with multilobulated nuclei and basophilic cytoplasm. Histopathological examination confirmed round CD3+/PAX5- cells packed in the dermis. Thus, the diagnosis of non-epitheliotropic cutaneous lymphoma with a diffuse large T-cell type was made. The disease progressed rapidly for the next 2 weeks, and the owner elected humane euthanasia.

The purpose of this study was to manually measure corneal thickness in canine eyes using a spectral-domain optical coherence tomography (SD-OCT) device and to assess intra- and inter-observer reliability of this technique. Twenty healthy dogs with a mean age of 4.7 y were examined. A 6-mm corneal pachymetry protocol was carried out by 1 operator using 1 SD-OCT device in both eyes of each animal. Measurements were obtained manually and in duplicate by 2 independent investigators (> 24 h apart), using the built-in caliper function. Measurements included epithelial thickness (ET), non-epithelial thickness (NET), and central corneal thickness (CCT). The overall mean ET, NET, and CCT for all eyes examined were 72.3 ± 4.6 μm, 538.9 ± 42.5 μm, and 611.2 ± 40.3 μm, respectively. There was no significant difference in ET, NET, or CCT based on the eye examined [oculus dexter (OD) versus oculus sinister (OS)], age, or gender of the animal. There was no significant difference in replicate measurements of ET, NET, or CCT done by the same operator, although a small but significant difference was noted between operators for ET measurements only. The mean difference in ET between operators was 0.6 μm (P = 0.03). The coefficient of variation ranged from 0.5% to 9.27% and intraclass correlation coefficient ranged from 0.35 to 0.97. Based on these results, manual measurements of corneal thickness in canine eyes using a portable SD-OCT device provided ET, NET, and CCT measurements with clinically acceptable intra- and inter-observer reliability.