Feasibility for Measuring Transverse Area Ratios and Asymmetry of Lumbosacral Region Paraspinal Muscles in Working Dogs Using Computed Tomography.

OBJECTIVES: Describe computed tomographic (CT) anatomy of canine lumbosacral (LS) paraspinal muscles, a method for measuring paraspinal muscle transverse area ratios and asymmetry using CT, and application of this method in a small sample of working dogs with versus without LS pain. METHODS: Published anatomy references and atlases were reviewed and discrepancies were resolved by examination of anatomic specimens and multiplanar reformatted images to describe transverse CT anatomy of LS region paraspinal muscles. Sixteen Belgian malinois military working dogs were retrospectively recruited and assigned to LS pain positive versus negative groups based on medical record entries. A single observer unaware of dog group measured CT transverse areas of paraspinal muscles and adjacent vertebral bodies, in triplicate, for L5-S1 vertebral locations. A statistician compared muscle transverse area ratios and asymmetry at each vertebral location between groups. RESULTS: The relative coefficient of variation for triplicate CT area measurements averaged 2.15% (N = 16). Multifidus lumborum (L6-7), psoas/iliopsoas (L5-6, L6-7), and sacrocaudalis dorsalis lateralis (L6-7, L7-S1) transverse area ratios were significantly smaller in dogs with LS pain (n = 11) versus without LS pain (n = 5) (p ≤ 0.05). Muscle asymmetry values were not significantly greater in dogs with versus without LS pain. CLINICAL RELEVANCE: Computed tomographic morphometry of LS region paraspinal muscles is a feasible objective method for use in future evidence-based research studies in working dogs. Potential future research applications include determining whether decreased paraspinal muscle area ratios and/or increased paraspinal muscle asymmetry could be used as markers for preclinical LS pain in stoic dogs or risk factors for other injuries in high performance canine athletes, or determining whether core muscle strengthening exercise prescriptions for dogs with LS pain have an effect on paraspinal muscle area ratios and asymmetry.

Feasibility and accuracy of ultrasound-guided sacroiliac joint injection in dogs.

Frozen cadaver specimens from three dogs were used to create a sectional anatomic atlas of the sacroiliac region. Frozen/thawed cadaver specimens from 12 dogs were used to develop an ultrasound-guided sacroiliac joint injection technique. Accuracy of the technique was tested in 15 additional canine cadaver specimens, using injectate containing blue dye and iodinated contrast medium. Sonoanatomic landmarks for consistently identifying a caudodorsal window into the canine sacroiliac joint space included the L7-S1 articular process joints, ilial wing, sacral wing, sacral lamina, and median sacral crest. Accuracy of ultrasound-guided sacroiliac joint injection was not significantly affected by operator, but was affected by the tissue location targeted and the reference standard used for calculations. Accuracy of the technique was good for placing injectate into either the synchondrosis component, dorsal sacroiliac ligament or ventral sacroiliac ligament; fair to poor for placing injectate into the synovial component; and poor for placing injectate into all four sacroiliac soft tissue structures. Concurrent placement of injectate into extraarticular tissues occurred frequently. We conclude that ultrasound-guided sacroiliac joint injection is feasible for evaluation as a treatment method for lumbosacral region pain in dogs, but is not sufficiently accurate for localizing pain to the sacroiliac joint alone.

Computed tomographic, magnetic resonance imaging, and cross-sectional anatomic features of the manus in cadavers of dogs without forelimb disease.

OBJECTIVE-To provide a detailed description of cross-sectional anatomic structures of the manus in canine cadavers in association with corresponding features in computed tomographic (CT) and magnetic resonance (MR) images. SAMPLE POPULATION-7 cadavers of adult large-breed-type dogs (weight range, 25 to 30 kg) without forelimb disease. PROCEDURES-Forelimbs were removed from the cadavers within 4 hours after euthanasia and frozen. The right forelimbs of 3 cadavers were cut into 4-mm sections by use of a band saw; 1 limb each was sectioned in the transverse, dorsal, or sagittal plane. Sections were cleaned and then photographed. After thawing, transverse CT images of the right forelimbs of 3 additional cadavers were obtained, and the right forelimb of a seventh cadaver underwent MR imaging in the transverse, sagittal, and dorsal planes. The evaluated regions extended from the digits to the carpus. Features in CT and MR images that corresponded to clinically important anatomic structures in tissue sections were identified. RESULTS-For most of the anatomic structures evident in tissue sections, corresponding CT and MR imaging features were identified. Osseous and musculotendinous structures of the manus were readily detected in CT and MR images, whereas vascular structures were only rarely identified by use of the imaging techniques. CONCLUSIONS AND CLINICAL RELEVANCE-Results of the detailed assessment of anatomic structures of the canine manus in association with corresponding features in CT and MR images will facilitate detection of pathological conditions and be beneficial in planning surgical procedures for diseases of the manus in dogs.

Late-gestation ventricular myocardial reduction in fetuses of hyperglycemic CD1 mice is associated with increased apoptosis.

BACKGROUND: Previous work in our laboratory showed reduced myocardium and dilated ventricular chambers in gestation day (GD) 17 hearts that were collected from hyperglycemic CD1 mouse dams. Pre-breeding maternal immune stimulation, using Freund's complete adjuvant (FCA), diminished the severity of these fetal heart lesions. The following experiments were performed to detect possible changes in fetal heart apoptotic cell death, under hyperglycemic conditions and with or without maternal immune stimulation. METHODS: Female CD1 mice were injected with 200 mg/kg of streptozocin (STZ) to induce insulin-dependent diabetes mellitus. Half of these mice received prior FCA injection. Fetal hearts were collected on GD 17 and myocardial apoptotic cells were quantified using flow cytometry. A panel of apoptosis regulatory genes (Bcl2, p53, Casp3, Casp9, PkCe) was then examined in the fetal myocardium using RT-PCR. RESULTS: Early apoptotic cells and late apoptotic/necrotic cells were significantly increased in fetal hearts from STZ or STZ+FCA dams. Pre-treatment with FCA reduced late apoptotic/necrotic cells to control level, suggesting some cell death protection was rendered by FCA. Paradoxically in the face of such increased cell death, the expression of pro-apoptotic genes Casp3 and Casp9 was decreased by diabetes, while the anti-apoptotic gene Bcl2 was increased. CONCLUSIONS: Maternal hyperglycemia causes dys-regulated apoptosis of fetal myocardial cells. Such effect may be prevented by maternal immune stimulation.

Heart changes in 17-day-old fetuses of diabetic ICR (Institute of Cancer Research) mothers: improvement with maternal immune stimulation.

Maternal diabetes mellitus is associated with increased fetal teratogenesis, including cardiovascular defects. Non-specific maternal immune stimulation with Freund's complete adjuvant (FCA) or interferon gamma (IFNgamma) has been associated with protection against birth malformations. Using a diabetic mouse model, late-gestation fetal heart and great vessel morphology were analyzed. Four groups of mice were used: non-diabetic females as a control group, hyperglycemic females induced by streptozotocin as a diabetic group, and diabetic females injected either with FCA or IFNgamma. At day 17 of gestation, females were euthanized and one fetus was arbitrarily selected per litter for fixation and sectioning. Treatment-induced changes in cardiac development were assessed from digital images of serial sections taken at standardized levels in the thorax. One-way parametric and non-parametric ANOVA and ordinal logistic regression were performed to compare the difference among groups (P<0.05). Maternal hyperglycemia altered morphology of the late-gestation fetal mouse heart by causing ventricular chamber dilation, sectional myocardial reduction, and an increase in transversal aortic area. FCA protected the fetal heart from cavitary dilation in diabetic mothers. FCA and IFNgamma protected the fetal heart against reduction of myocardial area, and ascending thoracic aorta dilation. Consequences of late gestation heart chamber dilation and myocardial reduction are not yet known. Maternal immune stimulation partially protected against these developmental defects by mechanisms that remain unclear.

Study of the vasculature of the caprine reproductive organs using the tissue-clearing technique, with special reference to the angioarchitecture of the utero-ovarian vessels and the adaptation of the ovarian and/or vaginal arteries to multiple pregnancies.

Arteries of the reproductive tracts of nonpregnant does and does at 4, 7, 10, 13, 16, and 18 weeks of gestation were injected in situ with Microfil. The tracts were fixed, dehydrated, and rendered transparent to reveal the paths of arteries. The tortuous ovarian artery lay in close apposition to the uterine tributary of the ovarian vein, an arrangement that may serve as a local utero-ovarian pathway for the corpus luteum (CL) luteolysis at the end of nonfertile estrous cycle. During pregnancy, this arteriovenous arrangement might transfer luteotropic substances from uterus to ovary, which might serve in maternal recognition of pregnancy and fit the fact that the goat is CL-dependent throughout gestation. In some cases of triplets, the size of the uterine branch of the ovarian artery was equal to or even larger than that of its parent artery and/or the ipsilateral uterine artery, and the vaginal artery contributed a connecting branch to the uterine artery. These physiological adaptations of the ovarian and/or vaginal arteries, which have not previously been described, correlate well with the increasing nutrient demands of the growing multiple fetuses.

Aortic and ventricular dilation and myocardial reduction in gestation day 17 ICR mouse fetuses of diabetic mothers.

BACKGROUND: Maternal diabetes mellitus is associated with increased fetal teratogenesis, including cardiovascular defects. Information regarding cardiovascular changes in late-gestation fetal mice, related to maternal hyperglycemia, is not present in the literature. METHODS: Late-gestation fetal heart and great vessel morphology were analyzed in fetuses from control and diabetic mice. Female ICR mice were injected with streptozocin (200 mg/kg IP) prior to mating to induce diabetes (n = 8). Nonhyperglycemic females were used as controls (n = 8). At day 17 of gestation, females were euthanized and one fetus was arbitrarily selected per litter to analyze the heart and great vessels. Six additional fetuses from different litters, showing external malformations (spina bifida and/or exencephaly), were also evaluated from the diabetic group. Fetal thoraxes were processed using routine histopathologic techniques, and 7-mum transversal sections were stained with hematoxylin-eosin. Digital images of sections were made and analyzed using NIH Image J software to compare regional cardiac development. Student's t tests for means were performed to determine differences between groups (p < .05). RESULTS: Maternal hyperglycemia caused a dilation of late-gestation fetal ventricular chambers, a reduction of total ventricular myocardial area, and an increase in transversal ascending thoracic aortic area. Three of six fetuses that displayed external malformations showed an overt cardiac defect, beyond the ventricular and myocardial changes. CONCLUSIONS: Maternal hyperglycemia altered morphology of the late-gestation fetal mouse heart. Postnatal persistence or consequences of late-gestation heart chamber dilation and myocardial reduction are not yet known.

Vascular distribution of contrast medium during intraosseous regional perfusion of the distal portion of the equine forelimb.

OBJECTIVE: To describe the vascular distribution pattern of contrast medium during intraosseous regional perfusion (IORP) of the distal portion of the equine forelimb. SAMPLE POPULATION: 13 cadaveric forelimbs from 12 horses without forelimb diseases. PROCEDURES: Serial lateromedial radiographic views were taken of the distal portion of 10 heparinized cadaveric forelimbs at 0, 1, 2, 6, 15, and 30 minutes during IORP of the third metacarpal bone (MCIII) by use of iodinated contrast medium and a tourniquet placed over the proximal portion of MCIII. Vascular regions of interest (ROI) were created for each radiograph. Reviewers identified the presence or absence of contrast medium-induced opacified vessels in all ROI on radiographs. This information was summarized to identify vessel-filling patterns over time. Vessel identification was verified by use of computed tomography angiography and latex perfusion studies on the distal portion of separate cadaveric forelimbs. RESULTS: During IORP, contrast medium filled the medullary cavity of the MCIII; exited via transcortical vessels; and diffused distally to the remaining arteries and veins of the forelimb, distal to the tourniquet. Maximum vessel and soft tissue opacification occurred in most specimens at 6 and 30 minutes, respectively. Serial radiography vessel patterns matched those of computed tomography images and dissected specimens. CONCLUSIONS AND CLINICAL RELEVANCE: IORP provides a repeatable pattern of vascular distribution in the distal portion of the equine forelimb. To our knowledge, our study provides the first documentation of arterial perfusion by use of IORP; results of previous reports indicate that IORP delivers medications to only the venous vessels of the perfused forelimb.

Evaluation of the internal vertebral venous plexus, vertebral canal, dural sac, and vertebral body via nonselective computed tomographic venography in the cervical vertebral column in healthy dogs.

OBJECTIVE: To evaluate nonselective computed tomographic (CT) venography for evaluating the cervical internal vertebral venous plexus (IVVP), define the diameter and area dimensions of the IVVP, and determine the relationship between dimensions of the cervical IVVP and other vertebral components in medium-sized dogs. Animals-6 healthy dogs that weighed 18 to 27 kg. Procedure-Helical CT scans were performed from C1 to C7 before and after IV injection of contrast medium (480 mg of iodine/kg) and a continuous infusion (240 mg of iodine/kg). Image data were transferred to a CT workstation, and measurements were performed on displayed transverse images. Diameter and area measurements of the vertebral canal, dural sac, IVVP, and vertebral body were obtained at C3 to C7. RESULTS: Opacification of vertebral venous structures was achieved in all dogs with no adverse reactions. Sagittal diameters of the IVVP for C3 to C7 ranged from 0.6 to 3.2 mm. Transverse diameters ranged from 2.32 to 5.74 mm. The IVVP area represented 12.4% of the mean vertebral canal transverse area and 30.61% of the mean vertebral epidural space area. Area measurements of the IVVP were significantly correlated with vertebral canal area and dural sac area. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that nonselective CT venography is a safe, sensitive method for performing morphometric assessments of the cervical IVVP in dogs. Findings support the theory that there may be a physiologic or developmental relationship between cervical vertebral canal components.

Computed tomographic anatomy of the canine cervical vertebral venous system.

Computed tomographic (CT) venography of the cervical vertebral canal was performed in six, clinically normal, adult mixed-breed dogs from 14 to 23 kg. After dogs were euthanized and saline perfused, a gelatin and iothalamate mixture was injected into the right external jugular vein. Contiguous, 4-mm-thick CT images were obtained with dogs in sternal recumbency. Dogs were kept in the same position as for the CT scan and frozen to approximately -8 degrees C. All post-contrast CT images were analyzed using similar bone window and level settings. Additional multiplanar reformatted dorsal images were obtained in all dogs. The frozen cadavers were sectioned through the cervical region extending from the occiput to T1 at approximately 8-mm intervals. The frozen sections were then compared with the CT images. The CT appearance of the normal cervical vertebral venous system was described and illustrated. Components such as the internal vertebral venous plexus, interarcuate veins, intervertebral veins, and vertebral veins were clearly identified on the CT images.

Revisión del plexo venoso vertebral en el perro / Review of the vertebral venous plexus in the dog

El plexo venoso vertebral en el perro es una extensa red vascular que se extiende a lo largo de la columna vertebral. Este sistema venoso se divide en tres componentes que se comunican entre sí; el plexo venoso vertebral interno; el plexo venoso vertebral externo y las venas basivertebrales. Debido a la creciente importancia clínica de este plexo venoso en medicina veterinaria, así como en medicina humana, el propósito de este artículo es revisar la literatura en relación con la anatomía, principales aspectos fisiológicos y clínicos del plexo venoso vertebral canino.