A non-invasive method for measurement of gastric emptying in mice: effects of altering fat content and CCK A receptor blockade.

The ability to make repetitive non-invasive measurements of gastric emptying of nutritive solids in awake, unstressed mice is highly desirable. The aim of the present study was to develop such a technique using nuclear scintigraphy and diets differing in triglyceride content. Awake mice were accustomed to light restraint and to feeding cooked, egg white (0.00 g fat g(-1)), whole egg (0.10 g fat g(-1)), or egg yolk (0.31 g fat g(-1)). Gastric emptying of each diet was measured by labelling the test meals with Technetium(99m) Mebrofenin and using a conventional gamma camera equipped with a high resolution, parallel hole collimator. Gastric emptying of cooked whole egg was also determined following administration of either vehicle or CCK A receptor antagonist, devazepide. The half-emptying time (t(1/2)) significantly increased with increasing triglyceride content from 14 +/- 5 min to 51 +/- 6 min and 82 +/- 4 min for egg white, whole egg and egg yolk, respectively. Administration of devazepide significantly decreased t(1/2) of whole egg to 28 +/- 2 min. These results demonstrate the sensitivity and predictability of this technique in mice and importantly, provide an opportunity to alter the macronutrient or caloric content of the meal to determine effects on gastric emptying.

Use of percutaneous ethanol injection for treatment of bilateral hyperplastic thyroid nodules in cats.

OBJECTIVE: To determine the efficacy and safety of percutaneous ethanol injection (PEI) for the treatment of hyperthyroidism caused by bilateral hyperplastic thyroid nodules in cats. DESIGN; Prospective study. ANIMALS: 7 cats. PROCEDURE: Hyperthyroidism was diagnosed on the basis of clinical signs and increased serum total thyroxine (TT4) concentrations. The presence of 2 cervical thyroid nodules was confirmed by use of ultrasonography and technetium Tc 99m albumin thyroid scans. After the death of 1 cat that received PEI in both thyroid nodules at the same time, the protocol was changed to injecting ethanol into 1 nodule at a time, with at least 1 month between injections. Clinical signs, serum TT4 concentrations, serum ionized calcium concentrations, laryngeal function, findings on ultrasonographic examinations of the ventral cervical region, and results of thyroid scans were monitored. RESULTS: Serum TT4 concentrations transiently decreased in all 6 cats (into the reference range in 5 of 6 cats) within 4 days of the first staged ethanol injection. Each subsequent injection resulted in a transient decrease in serum TT4 concentration. The longest period of euthyroidism was 27 weeks. Adverse effects included Horner's syndrome, dysphonia, and laryngeal paralysis. One cat died of unrelated causes. One cat underwent bilateral thyroidectomy, 2 cats were treated with methimazole, and 2 cats that had increased serum TT4 concentrations were not treated further, because they remained clinically normal. CONCLUSIONS AND CLINICAL RELEVANCE: Percutaneous ethanol ablation of bilateral thyroid nodules as a treatment for cats with hyperthyroidism is not recommended. This treatment is not as efficacious as the medical and surgical treatments presently used.

Percutaneous ultrasonographically guided radiofrequency heat ablation for treatment of primary hyperparathyroidism in dogs.

OBJECTIVE: To evaluate the efficacy and safety of ultrasonographically guided radiofrequency heat ablation of parathyroid masses in dogs with primary hyperparathyroidism. DESIGN: Clinical trial. ANIMALS: 11 dogs. PROCEDURE: In all dogs, either 1 or 2 parathyroid masses were evident ultrasonographically. Dogs were anesthetized, and a 20-gauge over-the-needle catheter was directed into the parathyroid mass via ultrasonographic guidance. Radiofrequency heat was applied to the stylet of the catheter until there was sonographically apparent change to the entire parenchyma of the mass. Serum total and ionized calcium and parathyroid hormone concentrations were monitored daily for 5 days after the ablation procedure and again at 1, 2, and 3-month intervals, if possible. Dogs were monitored for adverse effects. RESULTS: One treatment was required in 6 dogs, 2 treatments were required in 2 dogs, and treatment was unsuccessful in 3 dogs. Serum total and ionized calcium concentrations were within reference ranges within 2 days of the last procedure in all 8 successfully treated dogs. Serum parathyroid hormone concentration was decreased 24 hours after treatment in all 8 dogs. Hypocalcemia developed in 5 of the 8 successfully treated dogs, all of which required treatment. One dog had a transient voice change. Other adverse effects were not reported. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographically guided radiofrequency heat ablation of parathyroid masses is a safe and effective alternative to surgery in dogs with primary hyperparathyroidism.

Evaluation of interoperator variance in shunt fraction calculation after transcolonic scintigraphy for diagnosis of portosystemic shunts in dogs and cats.

OBJECTIVE: To determine interoperator variance in shunt fraction calculation. DESIGN: Case series. SAMPLE POPULATION: 101 transrectal portoscintigraphic studies. PROCEDURE: Results of dynamic portoscintigraphic studies were reviewed by 4 radiologists without knowledge of signalment, history, or medical profile. Results were judged to be negative or positive on the basis of the dynamic scan. Composite images were formulated, and hand-drawn regions of interest were determined for the heart and liver. Time-activity curves were generated, time-zero points were selected, curves were integrated during a 10-second interval, and shunt fractions were calculated. RESULTS: Radiologists were in agreement regarding positive versus negative results for 99 of 101 studies. Interoperator variance in shunt fraction calculation ranged from 0.4 to 59.6%. For 51 studies with positive results, variance ranged from 2.5 to 59.6% (mean +/- SD, 22.8 +/- 14.5%); differences among reviewers were significant. For 48 studies with negative results, variance in shunt fraction ranged from 0.4 to 25.9% (mean, 5.3 +/- 5.8%); significant differences among reviewers were not detected. Shunt fraction calculations were not exactly reproducible among radiologists in 94 and 100% of studies with negative or positive results, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that shunt fraction values are not reproducible among operators. Range in variability was greater in studies with positive results. This factor may be of particular clinical importance in reassessment of patients after incomplete shunt ligation.

Efficacy of a single oral dose of isorsorbide 5-mononitrate in normal dogs and in dogs with congestive heart failure.

Isosorbide 5-mononitrate (5-ISMN) was evaluated in normal dogs and dogs with congestive heart failure (CHF) in a randomized, blinded, and placebo-controlled study. Equilibrium blood pool imaging was used to detect changes in regional blood volume distribution. Six normal dogs were administered placebo, 2, 3, and 4 mg/kg 5-ISMN PO on separate days with a 1-week washout period between randomized dosings. Six dogs with CHF were administered placebo or 4 mg/kg 5-ISMN on separate days with a 1-week washout period between randomized dosings. Data were collected at baseline and at 15, 30, 45, 60, 90, 120, 150, 180, 210, and 240 minutes after dosing. Measured variables included indirect arterial blood pressure (BP), heart rate (HR), packed cell volume (PCV), scintigraphic count rates for normal dogs, and scintigraphic count rates for CHF dogs. Blood for plasma 5-ISMN concentration determination was collected at 60 minutes. Scintigraphic counts were corrected for decay and expressed as a percentage of the whole. No differences were detected in BP, HR, PCV, thoracic blood volume percentage (TBVP), or abdominal blood volume percentage (ABVP) between placebo and 5-ISMN in normal dogs at any dose. No differences were detected in TBVP or ABVP between placebo and 5-ISMN in dogs with CHF Plasma 5-ISMN concentration exceeded the minimum therapeutic concentration in all dogs and at all doses 60 minutes after drug administration. Equilibrium blood pool imaging failed to detect a shift in blood volume with oral 5-ISMN administration at any dose tested in normal dogs and dogs with CHF, despite adequate drug absorption. On the basis of the results of this study, 5-ISMN may not be beneficial in the treatment of dogs with CHF.

Intervertebral disc extrusion in six cats.

Existing reports concerning intervertebral disc disease (IVDD) have focused almost exclusively on dogs, although a small number of individual case reports of IVDD of cats has been published. The medical records of six cats with IVDD were reviewed. Radiographic studies confirmed narrowed intervertebral disc spaces, mineralised intervertebral discs, and one or more extradural compressive lesions of the spinal cord in each cat. All disc extrusions were located in the thoracolumbar region. Surgical decompression of the spinal cord was achieved in all cats by means of hemilaminectomy and removal of compressive extradural material confirmed to be degenerative disc material. Good to excellent neurological recovery was noted in five of the six cats included in this report. Based on this review, it appears that IVDD of cats has many similarities to IVDD of dogs, and that healthy cats with acute intervertebral disc extrusion(s) respond favourably to surgical decompression of the spinal cord.

Quantitative videofluoroscopic evaluation of pharyngeal function in the dog.

Videofluoroscopic evaluation of both liquid barium and barium soaked kibble was performed in 11 adult, clinically normal dogs of varying breeds. Each examination was digitized and evaluated frame by frame to establish the normal timing sequence of the pharyngeal phase of swallowing. Closure of the epiglottis was considered the onset of swallowing. The time to each of the following events was recorded: (1) Maximum pharyngeal contraction, (2) Opening of the epiglottis, (3) Opening of the cranial esophageal sphincter, and (4) Closure of the cranial esophageal sphincter. These values were found to be consistent both intra and interpatient. Retrospective analysis of 3 videofluoroscopic examinations from dogs that met the subjective criteria defining cricopharyngeal achalasia was then performed. A statistically significant delay in the time to opening and closure of the cranial esophageal sphincter was found employing both liquid barium and barium soaked kibble in the dogs with cricopharyngeal achalasia.

Scintigraphic detection of equine orthopedic infection using Tc-HMPAO labeled leukocytes in 14 horses.

The aim of this study was to evaluate the diagnostic value of 99mTc-HMPAO leukocyte scintigraphy (LS) by means of a retrospective review of its use in 14 horses that were evaluated for orthopedic infection as a cause of lameness. A total of 17 LS exams were performed in 14 horses. LS studies were positive in 10 of 14 horses. A bacterial infection was confirmed with cytology or culture in 9 of 10 positive horses. Negative LS studies occurred in 4 of 14 horses. Necropsy confirmed the lack of infection in 2 of the 4 horses. Other clinical data and a favorable clinical outcome supported a negative study in the other 2 horses. No false negative or false positive studies were identified. It may be concluded that HMPAO-LS is an effective tool for the diagnosis of orthopedic infection in horses.

Evaluation of samarium-153 for synovectomy in an osteochondral fragment-induced model of synovitis in horses.

OBJECTIVE: To determine the effects of intraarticular administration of Samarium-153 (153Sm) bound to hydroxyapatite microspheres (153SmM) on an osteochondral chip-induced synovitis. STUDY DESIGN: Sixty days after implantation of autogenous osteochondral fragments in the middle carpal and metacarpophalangeal joints, 153SmM was administered into 1 joint of each type. The contralateral joints were used as untreated controls. ANIMALS OR SAMPLE POPULATION: Fifteen horses without preexisting joint disease were randomly divided into 2 groups (7 in the carpal group, 8 in the metacarpophalangeal group). METHODS: Horses had osteochondral fragments that were harvested from the lateral ridge of the trochlea of the talus and implanted bilaterally into a middle carpal joint and a metacarpophalangeal joint; the opposite joint type served as a control. Sixty days later, 10 to 15 mCi of 153SmM (20 to 50 microm diam) was injected into the fragment-implanted joints. Three horses were treated with nonradioactive hydroxyapatite fragments. Horses were examined clinically until they were killed 14 or 30 days later. Control and treated joints were examined grossly and microscopically to determine the effects of 153SmM on synovial membrane and cartilage. RESULTS: Intraarticular 153SmM caused a transient flare with lameness, effusion, and edema for 48 to 72 hours. Implanted osteochondral chips induced a synovitis characterized by variable degrees of joint damage and synovial infiltrate. Use of 153SmM resulted in synovectomy of variable depth and extent. CONCLUSIONS: Intraarticular 153SmM may be a useful method for synovectomy of inflamed synovial membrane. CLINICAL RELEVANCE: With further testing, radioactive pharmaceuticals might become useful clinical treatments for persistent synovitis not responsive to conventional techniques.

Incomplete ossification of the humeral condyle in Vietnamese pot-bellied pigs.

The purpose of this study was to evaluate the occurrence of humeral condylar fractures in Vietnamese pot-bellied pigs and to postulate a possible predisposing cause for these fractures. Thirteen Vietnamese pot-bellied pigs (Group A) were evaluated over an eight year period (1990-1998), each with a history of either a unilateral or bilateral forelimb lameness. The cause of lameness was localized to the elbow region. Of the thirteen pigs, twenty-one elbows were evaluated radiographically. Pigs ranged in age from six months to four years old. All pigs over the age of seven months showed radiographic evidence of elbow degenerative joint disease. Fractures involving the medial aspect of the humeral condyle were identified in 8/21 studies (38%). A well-defined linear intracondylar articular lucency was identified in 7/21 studies (33%) on the craniocaudal projection. The site of this lucency corresponded to the location of the articular component of the fractures seen involving the humeral condyle. The elbows of five pot-bellied pigs with no known history of forelimb lameness or trauma (Group B) were evaluated radiographically following euthanasia. All five pigs were of unknown age and gender. An intracondylar vertical linear lucency was identified bilaterally in three pigs (60%). Concurrent degenerative joint disease was present in all instances. The remaining two pigs were radiographically normal. Computed tomography of the elbows was performed in one affected pig from Group B. The radiographic findings in this pig were verified. Histopathology of the right elbow of this affected pig was diagnostic for incomplete endochondral ossification of the humeral condyle. A similar condition involving the humeral condyle has been previously described in Cocker and Brittany Spaniels. These canine breeds also have a high incidence of humeral condylar fractures. It is postulated that Vietnamese pot-bellied pigs are similarly prone to humeral condylar fractures, even in the absence of known trauma, due to incomplete ossification of the humeral condyle.

Canine elbow dysplasia. The early radiographic detection of fragmentation of the coronoid process.

Ununited anconeal process, osteochondrosis, and fragmentation of the coronoid process (FCP), separately or together, comprise canine elbow dysplasia. Radiographic detection of ununited anconeal process or osteochondrosis is common, whereas identification of an FCP is often inferred by finding joint incongruity and secondary changes. Early identification of FCP can be improved by evaluating the elbow joint for subtle changes visible early in the course of this disease. Proper radiographic technique and positioning are essential in optimizing identification of the changes associated with mild or early FCP.

Samarium 153-labeled hydroxyapatite microspheres for radiation synovectomy in the horse: a study of the biokinetics, dosimetry, clinical, and morphologic response in normal metacarpophalangeal and metatarsophalangeal joints.

OBJECTIVE: To determine the effects of Samarium-153 bound to hydroxyapatite microspheres (153SmM) when injected into the metacarpophalangeal and metatarsophalangeal joints of horses. STUDY DESIGN: - Horses were injected with 153SmM in metacarpophalangeal and metatarsophalangeal joints with the diagonal contralateral joints used as untreated controls. ANIMALS OR SAMPLE POPULATION: Twelve adult horses without pre-existing disease involving the metacarpo/metatarsophalangeal joints. METHODS: Horses were divided into three groups: high-dose Samarium-153 (12.5 to 17.0 millicurie [mCi]), intermediate dose (6.5 to 12.0 mCi), and low dose (3.5 to 6.0 mCi). Horses were examined daily for 7 days postinjection for clinical abnormalities, lameness, and surface and systemic radiation levels. One horse from each group was euthanatized at 14, 30, and 60 days postinjection and the effects of the 153SmM examined microscopically in the cartilage and synovial membrane. RESULTS: Intraarticular(153)SmM caused inflammation characterized by lameness, effusion, and regional edema for 48 to 72 hours. Minimal levels of active 153SmM were identified in the blood or urine and were well below the maximal tolerance of 1 mCi. Microscopically the radiation caused no effects on the articular cartilage. The synovectomy created was good but not ideal in that some areas did have necrosis into the subintimal regions and a few islands of intact intimal cells persisted. CONCLUSIONS: The use of 153SmM is an effective means of targeting the synovial intimal cells with minimal extrasynovial leakage of radiation. CLINICAL RELEVANCE: The metacarpophalangeal and metatarsophalangeal joints of the horse can be safely treated with 153SmM without damage to the cartilage or significant extracapsular leakage.

Surgical repair of a thoracic meningocele in a foal.

A 6 week old American Paint filly was admitted for evaluation of a dorsal thoracic mass suspected to be a meningocele. The diagnosis was confirmed by plain and contrast enhanced computed tomography. Surgical repair was performed by dissection of the base of the meningocele followed by ligation. No postoperative complications occurred. Contrast enhanced computed tomography was useful to confirm the diagnosis of meningocele and rule out a meningomyelocele.

Percutaneous ultrasound-guided trans-splenic catheterization of the portal vein in the dog.

The purpose of this investigation was to develop a safe and reliable technique for percutaneous catheterization of the portal vein via a major splenic vein using ultrasound guidance. Three separate catheter systems were evaluated on five anesthetized dogs. At least five attempts at catheterization of the splenic vein and subsequently the portal vein were attempted on each animal. Following the procedure the dogs were necropsied to assess for intrasplenic and intraabdominal hemorrhage. A technique using an introducer system and a large catheter was not successful on seven attempts. A technique using an over the needle catheter was successful in gaining access to the splenic vein on two out of five attempts; however the catheter could not be advanced into the portal vein. A technique utilizing 19 or 17 gauge needles with 22 or 19 catheter through-the-needle-catheters was successful in catheterization of the splenic vein and advancement to the portal vein on twelve of fifteen attempts. The smaller gauge needle and catheter system provided for easier access to the splenic vein and subsequent catheter manipulation facilitating access to the portal circulation.

A client server model to facilitate creation of a medical image teaching library.

A simple and convenient system for indexing and archiving medical images used in teaching was developed. The approach was to combine a smart client-side graphical user interface that controlled image size, file format, and keyword structure, and communicated with the hospital information system via hypertext mark-up language, to populate the interface with user selectable pull-down menus. The result is a system that is easily extensible beyond the radiology images for which it was originally designed. Only minor modifications of the client interface are required to adapt the program to accept any file format or image type.

Ultrasonographic evaluation of renal autografts in normal cats.

The purpose of this study was to determine changes in resistive index (RI) and renal size that occur in normal feline kidney autografts in the immediate post-transplant period. Qualitative changes in renal parenchymal echogenicity and pelvic dilation were also noted, although this was not a major focus of the study. Fourteen domestic short-haired cats underwent bilateral nephrectomies followed by an autograft of the right kidney to either the aorta or external iliac artery. Due to post-operative complications, only nine of these cats completed the study. Ultrasonographic determination of the RI and renal size was made before transplantation and on days 1, 4, 7, 10, and 13 following transplantation. No significant changes in renal RI were identified during the study. Renal size increased significantly, peaking at 63% above baseline on day 7, and stayed elevated at 50% above baseline on day 13. There was no evidence of rejection or other abnormalities found on histologic evaluation of the transplanted kidneys. It was concluded that the RI of normal feline renal autografts does not significantly change in the immediate post-operative period. However, significant renal enlargement, likely due to a combination of post-operative edema and hypertrophy, does occur. This study provides baseline information for comparison with feline allografts in the immediate post-transplant period.

Percutaneous ultrasound-guided chemical parathyroid ablation for treatment of primary hyperparathyroidism in dogs.

OBJECTIVE: To evaluate the efficacy, feasibility, and safety of ultrasound-guided chemical ablation of parathyroid masses in dogs with primary hyperparathyroidism. DESIGN: Prospective clinical trial. ANIMALS: 8 dogs. PROCEDURE: In all dogs, a solitary parathyroid mass was evident ultrasonographically. Dogs were anesthetized with propofol, and a 27-gauge needle was directed into the parathyroid mass under ultrasound guidance. Ethanol (96%) was injected into the mass until there was evidence of diffusion of fluid throughout the mass. Serum total calcium, ionized calcium, phosphorus, and parathyroid hormone (PTH) concentrations were monitored daily for 5 to 7 days after the ablation procedure and again 1, 3, and 6 months after the procedure. Dogs were also monitored for adverse effects. Follow-up ultrasonography was performed 5 days and 1 month after the ablation procedure. RESULTS: One injection was required in 7 dogs, and 2 injections were required in 1. Serum total and ionized calcium concentrations were within reference ranges within 24 hours after treatment in 7 dogs and within 5 days in 1 dog. Serum PTH concentration decreased and serum phosphorus concentration increased within 24 hours after treatment in all 8 dogs. Transient hypocalcemia developed in 4 dogs during the first 5 days after treatment, but only 1 dog required treatment for hypocalcemic tetany. Hypercalcemia recurred in 1 dog 1 month after the procedure and surgical removal of the parathyroid mass was required. Other adverse effects were not reported. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided chemical ablation of parathyroid masses is a safe and effective alternative to surgery for dogs with primary hyperparathyroidism.

Development of an automated 12-8 bit conversion algorithm for displaying and archiving scanned radiographs.

The lossless capture of the entire range of optical densities encountered in a radiograph can require up to 4000 individual shades of gray. Most inexpensive computer displays, and most grayscale image formats contain only 256 gray shades. To use these systems, a look up table must be generated to display the scanned image, which maps the approximately 4000 gray shades in the digitized radiograph to the 256 gray shades on the monitor. However, if this conversion is inappropriately performed, much of the information contained in the original image could be lost. This study was undertaken to develop an histogram equalization algorithm that would automatically convert the 4000 gray shade digitized radiograph into a 256 gray shade image file, without perceptable loss of diagnostic information or image quality.