Browsing by Author "Jones, Jeryl C."
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- A comparison of radiography versus computed tomography in the diagnosis of middle ear disease in the dogRohleder, Jacob John (Virginia Tech, 2004-04-14)The purpose of this study was to compare CT and radiography for diagnosing the presence and severity of middle ear disease in dogs with chronic otitis externa. Thirty-one dogs that were presented for a total ear canal ablation and bulla osteotomy were recruited. Three normal dogs served as controls. All dogs were examined using radiography and CT. Three radiologists independently evaluated imaging studies in random order. A visual analog scale method was used for scoring certainty and severity of middle ear disease. Surgical findings were recorded intra-operatively. Bulla lining samples were submitted for histopathology and scored by a single pathologist who also used a visual analog scale system. Findings from both modalities agreed more closely with surgical findings than with histopathology findings. With either surgery or histopathology as the gold standard, CT was more sensitive than and as specific as radiographs for predicting presence and severity of middle ear disease. Overall severity of middle ear disease was lower in the right versus the left ears. For CT, inter-observer variance of middle ear certainty was 217.04 while radiographic variance was 126.14 on the side with lower severity estimates. Both radiography and CT were more accurate for predicting the severity of the disease than its presence. Findings indicate that CT is more accurate and reliable than radiography in diagnosing middle ear disease for dogs with chronic otitis externa, but only when severity of disease is moderate or high. With low severity of disease, reader diagnostic certainty for both modalities becomes more variable.
- Diagnostic Imaging of Foreign Bodies and Compartmentalization in the Canine ManusOber, Christopher Patrick (Virginia Tech, 2009-03-17)Injury of the manus is an important cause of morbidity and function loss in dogs, especially working breeds. These injuries may cause foreign body retention and can lead to persistent infection. Accurate methods for diagnosis and localization of pathology in this anatomically complex region are critical to minimize patient morbidity, guide surgical planning, and improve case outcomes. The anatomy of the canine manus was evaluated with computed tomography (CT), magnetic resonance imaging (MRI), and transverse anatomic sections. Most structures identified on transverse sections were visible on both CT and MRI images. Detail in the osseous structures was better in CT images, while MRI provided increased contrast of soft-tissue structures. To test the hypothesis that diagnostic accuracies of CT, MRI, and ultrasound differ for detection of acute wooden foreign bodies in the canine manus, we inserted wooden splinters into canine cadaver manus and imaged each manus with all three modalities. Receiver operating characteristic curve analysis demonstrated that CT was most accurate for detection of acute wooden foreign bodies, followed in turn by ultrasound and MRI. Diseases in the human hand and foot are often confined by soft-tissue spaces, but similar structures have not been described in the dog. To determine if these spaces are present in the canine manus, we injected contrast medium into likely spaces and compartments in cadaver specimens, imaged the limbs with CT, and dissected the injected manus specimens. We found thirteen discrete soft-tissue spaces and five myofascial compartments that are similar to those described in the human hand. To test the hypothesis that spread of disease in the canine manus can be modeled and predicted, we injected cadaver interdigital web spaces with contrast medium, imaged them with CT, and dissected them. We found that the pattern of contrast agent spread, as a model of infection, was predictable and unique to the initial injection site. Findings from these cadaver studies improve our understanding of anatomy, imaging of wooden foreign bodies, and likely patterns of disease extension in the canine manus. Future studies are needed to test the utility of this information for surgical planning in affected clinical patients.
- Diffusion Weighted MR Imaging in the Differentiation between Metastatic and Benign Lymph Nodes in Canine Patients with Head and Neck DiseaseStahle, Jessica Anne (Virginia Tech, 2016-07-14)In dogs with large primary tumors, regional lymph node involvement or evidence of distant metastasis can have worse prognoses and significantly decreased survival. Lymph node size alone has been shown to be insufficient as a predictor for the accurate clinical staging of some canine neoplasia, including oral malignant melanoma. However, regional lymph nodes of the oral cavity, such as the medial retropharyngeal lymph nodes, are difficult to access for routine sampling. Diffusion weighted magnetic resonance imaging (DWI) has demonstrated the ability to differentiate metastatic from inflammatory/benign lymph nodes in clinical studies with human cancer patients through the calculation of quantitative values of diffusion termed apparent diffusion coefficients (ADC). The objective of this exploratory study was to evaluate DWI and ADC as potential future methods for detecting malignant lymph nodes in dogs with naturally occurring disease. We hypothesized that DWI would identify significantly different ADC values between benign and metastatic lymph nodes in a group of canine patients with head or neck disease. Our results demonstrated that two of four observers identified a significant difference between the mean ADC values of the benign and metastatic lymph nodes. When data from all four observers were pooled, the difference between the mean ADC values of the benign and metastatic lymph nodes approached but did not reach significance (P-value: 0.0566). Therefore, our hypothesis was not supported. However, DWI does show promise in its ability to differentiate benign from metastatic lymph nodes, and further studies with increased patient numbers are warranted
- The Effect of CT Display Window and Image Plane on Diagnostic Certainty for Characteristics of Canine Elbow DysplasiaTromblee, Tonya Christine (Virginia Tech, 2006-05-11)Computed tomography (CT) is an established diagnostic modality for evaluation of canine elbow dysplasia. However, diagnostic sensitivity for elbow abnormalities may be affected by variations in CT image quality. Currently there are no data-based recommendations for elbow CT image display parameters. The purpose of this study was to test the effect of CT display parameters on observers' diagnostic certainty for CT abnormalities reportedly associated with canine elbow dysplasia. Fifty dysplastic elbows and ten clinically normal elbows were selected for imaging. Computed tomographic image data from selected elbows were filmed in transverse, sagittal and dorsal planes, with each plane filmed in window widths of 1500, 2500, and 3500 HU. Two veterinary radiologists independently evaluated each set of images for the presence or absence of hypoattenuating MCP subchondral defects, in situ MCP fissures, discrete MCP fragments, irregularity of the radial incisure of the ulna, subchondral sclerosis of the trochlea humeri, osteochondrosis or kissing lesions, and joint incongruity. Level of diagnostic certainty for each CT abnormality was recorded for each observer using a visual analog scale system. The effect of elbow status, plane, and window on the degree of observer certainty was tested. Overall, observers demonstrated higher diagnostic certainty for normal elbows than dysplastic elbows. Observer certainty for the presence of altered subchondral density (presumed osteomalacia or sclerosis) was primarily affected by window width, whereas certainty for structural defects of the MCP, radial incisure, trochlea humeri, and joint incongruity was primarily affected by image plane.
- Effects of Electrically-Stimulated Silver-Coated Implants and Bacterial Contamination in a Canine Radius Fracture Gap ModelWright, Russell Eric (Virginia Tech, 2000-06-09)The purpose of this project was to study the effects of anodic electrically stimulated silver-coated stainless steel implants and bacterial contamination in a canine radius fracture gap model. Twelve skeletally mature canines weighing 19.2-23.2 kg were used. Dogs were randomly assigned to into control and contaminated groups. A 5 mm ostectomy gap was made in both radii of each dog. One radius of each dog was stabilized with a silver-coated stainless steel bone plate and the other with an uncoated stainless steel bone plate. The ostectomy sites were inoculated with sterile PBS in 6 dogs and S. intermedius in the other 6 dogs. Each implant set was electrically stimulated with direct current for 20 minutes daily, for 10 days. Animals were treated with Cephalexin orally for 10 days. Radiographs were obtained at two week intervals. Animals were euthanized at 12 weeks and each plate was cultured. Radiographic, histologic and bacteriologic evaluations of each radius were performed. The difference in bone healing between silver-coated and stainless steel treated radii was determined for each dog by subjective radiographic evaluation and quantitative analysis of radiographic density using commercial software. At week 12, a significant decrease in bone healing was found on radiographic evaluations and quantitative bone area analysis of contaminated radii that were treated with electrically stimulated silver-coated implants (p-value 0.025 and 0.018 respectively). Inoculum or implant treatment type showed no significant difference on radiographic evaluations or quantitative bone area analysis. No significant differences were detected in radiographic evaluations of osteomyelitis or histologic evaluations of bone healing, inflammation and peri-implant resorption. Culture results were not indicative of S. intermedius inoculated osteomyelitis. The use of a bilateral radial ostectomy model allowed comparison of electrically stimulated silver-coated and uncoated implants within each dog. Bone healing in the stable 5 mm fracture gap radial ostectomy model, was progressive in both contaminated and non-contaminated situations. Our study found a negative effect on bone healing when electrically-stimulated silver stearate coated implant were used in S. intermedius contaminated radius ostectomies. This trend became apparent at 6 weeks post-operatively, but was not statistically evident until 12 weeks. Further studies are warranted to evaluate the appropriate protocol, the effects of, and indicated use of this treatment modality in contaminated fractures and clinical osteomyelitis situations.
- Endoscopic-Assisted Lumbosacral Foraminotomy in the DogWood, Brett (Virginia Tech, 2004-01-13)Objective - To determine if an endoscopic-assisted foraminotomy significantly increases the area of the L7-S1 intervertebral foramen and if, over a 12-week time period, there is stenosis of the treated foramen. Study Design - Prospective, experimental study Animal Population - Six, clinically normal adult dogs. Methods - Using endoscopic assistance a unilateral L7-S1 foraminotomy was performed. Computed tomography of the region was performed in the pre-operative, immediately post-operative and 12-week post-operative time periods. Parasagittal area measurements were obtained at the entry, middle and exit zones of the treatment and control foramen for each period. Objective and subjective data were compared among dogs, by time period and treatment status. Results - Endoscopic assisted foraminotomy resulted in a significant increase in the mean parasagittal foramen area (mPFA) of the entry and middle zones in the immediate post-operative period. The exit zone was not made significantly larger at any time period. The foramen remained significantly larger at the 12-week post-operative period in the middle zone only. However, some decrease in the surgically created foramen enlargement occurred at all three levels. The dogs tolerated the procedure well, but did have a mild, temporary delay of functional return post-operatively. Conclusions - Endoscopic assisted foraminotomy in the canine patient can be performed for certain regions of the foramen allowing enhanced visibility in the spinal canal during the procedure. The foramen can be surgically enlarged at the entry and middle zones using this technique. There is some reduction of the foraminal enlargement at 12-weeks post-operative. The clinical significance of this reduction is not evident from this study. Clinical Relevance - Endoscopic assisted foraminotomy could be used to improve intra-operative visualization in dogs with foraminal stenosis as a component of degenerative lumbosacral stenosis.
- Evaluation of the Normal Equine Pituitary GlandMcKlveen, Tori Leigh (Virginia Tech, 2003-07-21)Computed tomography (CT) is becoming more available as a diagnostic tool in the evaluation of the equine skull and brain. Objectives of this study were: 1) refine a CT protocol for evaluating the equine pituitary gland, 2.) define the CT anatomy of the pituitary region, 3.) determine a set of normal values for the pituitary dimensions (length, width, height, volume and weight), 4.) refine CT techniques for measuring pituitary size. Horses were scanned using 10x10mm, 10x5mm, 4x4mm and 4x2mm slice thickness and interval combinations. The pituitary glands were removed immediately after CT and gross measurements were performed. CT measurements were compared with gross pituitary measurements using analysis of variance (ANOVA) in a randomized block design. Accuracy percentages were also calculated using gross measurements as the known value. Mean dimensions of the histologically normal pituitary glands were: length 21.07mm, width 21.62mm, height 9.78mm and volume 2.66cm³. The weights ranged from 1.7g to 3.4g with a mean of 2.6g. Computed tomographic measurement analysis demonstrated that the 10mm slices were the most accurate way to estimate the length of the gland. The 4mm slices yielded the highest accuracy values for width, height and volume of the pituitary gland. The volume was underestimated by all interval and slice thickness combinations performed by CT. No evidence of an overlap effect was identified for any of the dimensions. Our findings indicated that contrast-enhanced CT is an accurate technique for estimating pituitary linear dimensions. Three-dimensional CT volumetry may not be an accurate method for estimating pituitary volume.
- Feasibility for Measuring Transverse Area Ratios and Asymmetry of Lumbosacral Region Paraspinal Muscles in Working Dogs Using Computed TomographyCain, Bethany; Jones, Jeryl C.; Holaskova, Ida; Freeman, Larry E.; Pierce, Bess J. (Frontiers, 2016)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.
- Imaging Studies of the Canine Cervical Vertebral Venous PlexusGomez Jaramillo, Marcelo A. (Virginia Tech, 2005-01-14)The internal vertebral venous plexus (IVVP) is an extensive vascular network recently implicated in various human and canine spinal disorders. Nevertheless, little recent information is available regarding normal anatomy of canine IVVP and its role in acute spinal injuries. The objectives of the study were; (1) to describe the normal IVVP morphology in the canine cervical region using transverse anatomy sections and computed tomography (CT), (2) to develop a technique for CT examination of the IVVP in vivo, (3) to analyze the quantitative characteristics of the IVVP, and (4) to assess the effect of acute experimental spinal cord compression on IVVP morphology. In the first experiment, CT of the cervical vertebral canal was performed in 6, normal, adult mixed-breed dogs. After dogs were euthanized, a gelatin and iothalamate mixture was injected into the right external jugular vein. Cadavers were then frozen to â 8°C, sliced into transverse sections, and compared with CT images. Vascular components such as the IVVP, interarcuate veins, intervertebral veins, and vertebral veins were accurately depicted on CT images. In the second experiment, CT venography was performed using a biphasic IV injection of iodinated contrast medium. Dimensions of the IVVP and other vertebral canal components were calculated for the C3-C7 vertebral region. Sagittal diameters of the IVVP ranged from 0.6 mm to 3.2 mm. The IVVP area occupied 30.61% of the cervical vertebral epidural space area. When C3-C7 segments were considered as a group, IVVP area dimensions were significantly correlated (r > 0.7, p < 0.0001) with vertebral canal area and dural sac area. In the last experiment, acute spinal cord compression (ASCC) was induced and maintained for 10 minutes using an angioplasty balloon catheter device over the C3/4 vertebral region in 6 dogs. Dogs were evaluated prior to, during, and after compression using digital subtraction venography (DSV) and CT venography. Results showed that ASCC produced a significant change in diameter of the IVVP at the site of compression. This effect persisted during the post-compression period. In conclusion, findings indicate that CT venography and DSV accurately depict the IVVP in dogs, and that significant changes of the IVVP morphology occur under ASCC conditions.
- A New Device for Stereotactic ct-Guided Biopsy of the Canine Brain: Design, Construction, and Needle Placement AccuracyGiroux, Alain G. (Virginia Tech, 2000-05-31)Computed tomography (CT) is an imaging technique that uses x-ray and computers to create cross-sectional images of structures. Stereotactic CT-guided biopsy is defined as the use of a stable apparatus to direct and perform tissue biopsies under CT guidance. For the brain, the principal advantage of stereotactic CT guidance over other biopsy techniques is its high accuracy in getting a sample from deep-seated lesions. The objectives of this study were to create an inexpensive CT-guided stereotactic device adaptable to different canine head sizes and to test the accuracy of the device for needle placement in deep-seated brain targets. A biopsy device was created that consists of four main components: a CT table fixation device, a head fixture, a needle fixture , and motion control system. Accuracy was tested using 16 head and neck specimens obtained from dogs euthanitized for reasons unrelated to the brain. Deep-seated (caudate nucleus and pituitary gland) targets were identified on CT. After a 5 mm craniotomy, the biopsy needle, with CT monitoring, was progressively introduced into the target. The final needle track distance was measured on CT. The brain was removed and sliced to verify placement of the needle tip within the target and to measure the actual needle track distance. The total cost of materials and construction for the stereotactic CT-guided biopsy device was $785.00. No difference in needle placement accuracy was identified for caudate and pituitary targets. Based on assessments by 2 independent observers, the caudate target was successfully hit 75% of the time. Pituitary targets were successfully hit 96.8 % of the time. Actual needle track lengths were an average of 3.2 mm less that the track length measured on CT. This difference was most likely due to incomplete staining of the bevel part of the needle track on gross specimens.
- Vascular distribution of contrast medium during intraosseous regional perfusion in the equine distal limbKeys, Graham Jeffrey (Virginia Tech, 2006-05-04)Objective — To describe the vascular distribution pattern of contrast medium during intraosseous regional perfusion (IORP) of the distal portion of the forelimb in horses. Sample Population — 13 cadaver forelimbs from 12 horses without vascular or orthopedic disease of the distal forelimb. Procedure — Serial lateromedial radiographs were taken of 10 heparinized cadaver distal forelimbs at 0, 1, 2, 6, 15, and 30 minutes during IORP of the third metacarpal bone (MCIII) using iodinated contrast medium and a tourniquet placed over the proximal MCIII. Vascular regions of interest (ROI) were created for each radiograph. Reviewers identified presence or absence of contrast in each ROI. This information was summarized to identify vessel-filling patterns over time. Vessel identification was verified using computed tomography angiography and latex perfusion studies on separate cadaver distal forelimbs. Results — During IORP, contrast medium filled the medullary cavity of the MCIII, exited via trans-cortical vessels and diffused distally to the remaining arteries and veins of the limb, 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 CT images and dissected specimens. Conclusions and Clinical Relevance — Intraosseous regional perfusion provides a repeatable pattern of vascular distribution in the distal portion of the equine forelimb. This is the first documentation of arterial perfusion using this technique. Previous reports indicate that IORP only delivers medications to the venous vessels of the perfused limb. Maximum soft tissue perfusion was observed at 30 minutes.