Comparison of health parameters in normal cats fed a limited iodine prescription food vs a conventional diet.

Objectives The objective was to compare the effect on thyroid function in healthy, adult cats fed a limited-iodine food or conventional diet for 24 months. Methods Cats in the limited-iodine group (n = 14) were fed a commercial, dry food containing 0.2 ppm iodine on a dry-matter basis (DMB). Cats in the conventional diet group (n = 12) were fed an identical diet except that the iodine content was 3.2 ppm on a DMB. Both groups were maintained on their respective diets for 24 months. The median age of the cats at baseline was 3.2 years (interquartile range 2.4-4.3). Diagnostic samples were obtained for measurement of serum biochemistry parameters, thyroid hormone concentrations, complete blood count and urinalysis, and thyroid ultrasound examination was performed at baseline, 6, 12, 18 and 24 months. Results Median serum concentrations of free and total thyroxine and thyroid-stimulating hormone were within respective reference intervals for both test groups at all sampling intervals. Median urine iodine concentrations in the limited-iodine group declined significantly ( P = 0.0001) from baseline and were significantly different than conventional diet ( P ⩽0.0007). Ultrasound examination revealed no significant change in median thyroid height in the limited-iodine group at any time point. Conclusions and relevance Normal serum thyroid hormone concentrations and results of urinalysis and routine biochemical testing confirmed that the limited-iodine food was safely fed for 2 years to healthy, adult cats. Ultrasound examination showing that cats on limited-iodine did not develop a change in thyroid gland height was a further indication of the absence of iatrogenic hypothyroidism in the limited iodine diet group. These results support the lack of obvious side effects associated with feeding a limited-iodine diet for 2 years to healthy, adult cats, a situation that may occur in multi-cat households where healthy cats have access to a limited-iodine diet being used to manage cats with feline hyperthyroidism.

Prospective Evaluation of Intra-Articular Dextrose Prolotherapy for Treatment of Osteoarthritis in Dogs.

The objective of this study was to evaluate intra-articular dextrose prolotherapy for osteoarthritis of the elbow or stifle in dogs in a randomized, double-blind, placebo-controlled, prospective pilot study. Seventeen dogs were evaluated with 10 meeting inclusion criteria for this study. Evaluations included orthopedic exam, visual lameness scoring, Canine Brief Pain Inventory (CBPI), goniometry, kinetic gait analysis, and radiography. Initial lameness score, age, body weight, duration of lameness, and CBPI scores did not differ between groups. Change in CBPI pain severity score in the prolotherapy group from wk 6-12 was significantly less improved than in the placebo group, with no other significant differences in pain severity or pain interference scores between groups. Range of motion and radiographic scores did not differ between groups at any time. Mean kinetic forces improved in prolotherapy dogs but were not significantly different between treatment groups at any time. Although easily performed and well-tolerated, there were no statistically significant benefits of dextrose prolotherapy for treatment of osteoarthritis of the elbow and stifle in dogs. Post hoc power analysis of these sample means and standard deviations found that 29-106 animals per group would be necessary to demonstrate significant differences in kinetic forces, providing useful guidance for future studies.

Pre-operative fibrous osteodystrophy and severe, refractory, post-operative hypocalcemia following parathyroidectomy in a dog.

A 13-year-old dog exhibited dramatic, radiographic osteopenia consistent with fibrous osteodystrophy secondary to primary hyperparathyroidism. Following parathyroidectomy, the dog developed severe, prolonged hypocalcemia, but was successfully treated and discharged 32 d after surgery. A variety of factors may have contributed to this dog's hypocalcemia including hypoparathyroidism and hungry bone syndrome.

Ostéodystrophie fibreuse préopératoire et hypocalcémie grave, réfractaire postopératoire après une parathyroïdectomie chez un chien. Un chien âgé de 13 ans a manifesté une ostéopénie radiographique dramatique conforme à une ostéodystrophie fibreuse secondaire à un hyperparathyroïdisme primaire. Après une parathyroïdectomie, le chien a développé une hypocalcémie grave et prolongée, mais il a été traité avec succès et a reçu son congé 32 jours après la chirurgie. Divers facteurs peuvent avoir contribué à l'hypocalcémie de ce chien, y compris l'hypoparathyroïdisme et l'hypocalcémie par avidité osseuse.(Traduit par Isabelle Vallières).

Nephrectomy in an Asian small-clawed otter (Amblonyx cinereus) with pyelonephritis and hydronephrosis secondary to ureteral obstruction.

A 10-yr-old, captive, intact male Asian small-clawed otter (Amblonyx cinereus) with a history of bilateral nephrolithiasis was presented for acute-onset lethargy and inappetance of 5 days duration. On physical examination, the otter was about 8% dehydrated and a palpable fluid wave was present in the abdomen. An abdominal ultrasound revealed hydronephrosis of the left kidney and a hyperechoic structure present within the lumen of the left ureter, causing an obstruction. A urinalysis revealed struvite crystalluria, bacteriuria, and an elevated pH. Following 4 days of antibiotic therapy, a left ureteronephrectomy was performed. Upon opening the kidney to retrieve calculi, a large amount of purulent material was noted within the renal pelvis. To the authors' knowledge, this is the first documented case of a nephrectomy in an Asian small-clawed otter. Nephrectomy should be considered as a viable option for treatment of ureteral obstruction, hydronephrosis, or severe pyelonephritis.

Identification and effects of common errors and artifacts on the perceived quality of radiographs.

OBJECTIVE: To identify common errors in film and digital radiographs provided by referring veterinarians and determine the effect of such errors on the perceived diagnostic quality of image sets. DESIGN: Prospective study. SAMPLE: 135 sets of radiographic images acquired by referring veterinarians for client-owned small animals evaluated at a university hospital. PROCEDURES: Sets of radiographs were prospectively collected and evaluated for proper performance of various radiographic technical variables including exposure, collimation, positioning, inclusion of all appropriate views, presence of artifacts, radiation safety, and labeling. Sets of radiographs were subjectively determined to be of diagnostic or nondiagnostic quality by 2 evaluators. RESULTS: The variables exposure, correct positioning, absence of artifacts, and acquisition of all appropriate views were significantly associated with a determination of diagnostic quality for radiograph sets. Correct patient labeling, radiation safety, and x-ray beam centering and collimation were not associated with a determination of diagnostic quality for radiograph sets. The number of categories with errors was significantly associated with identification of radiograph sets as having diagnostic or nondiagnostic quality. Digital radiographs had a significantly lower number of image artifacts and significantly higher frequency of proper labeling versus film radiographs. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study suggested the technical variables proper exposure, proper positioning, absence of artifacts, and acquisition of all appropriate views were important for acquisition of sets of radiographs of high diagnostic quality. Identification of these errors and adjustment of radiographic technique to eliminate such errors would aid veterinarians in obtaining radiographs of high diagnostic quality and may reduce misinterpretation.

Comparison of three-view thoracic radiography and computed tomography for detection of pulmonary nodules in dogs with neoplasia.

OBJECTIVE: To compare the detection of pulmonary nodules by use of 3-view thoracic radiography and CT in dogs with confirmed neoplasia. DESIGN: Prospective case series. ANIMALS: 33 dogs of various breeds. PROCEDURES: 3 interpreters independently evaluated 3-view thoracic radiography images. The location and size of pulmonary nodules were recorded. Computed tomographic scans of the thorax were obtained and evaluated by a single interpreter. The location, size, margin, internal architecture, and density of pulmonary nodules were recorded. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for thoracic radiography (with CT as the gold standard). RESULTS: 21 of 33 (64%) dogs had pulmonary nodules or masses detected on CT. Of the dogs that had positive CT findings, 17 of 21 (81%) had pulmonary nodules or masses detected on radiographs by at least 1 interpreter. Sensitivity of radiography ranged from 71% to 95%, and specificity ranged from 67% to 92%. Radiography had a positive predictive value of 83% to 94% and a negative predictive value of 65% to 89%. The 4 dogs that were negative for nodules on thoracic radiography but positive on CT were all large-breed to giant-breed dogs with osteosarcoma. CONCLUSIONS AND CLINICAL RELEVANCE: CT was more sensitive than radiography for detection of pulmonary nodules. This was particularly evident in large-breed to giant-breed dogs. Thoracic CT is recommended in large-breed to giant-breed dogs with osteosarcoma if the detection of pulmonary nodules will change treatment.

Estimation of glomerular filtration rate in healthy cats using single-slice dynamic CT and Patlak plot analysis.

Commonly used clinical indicators of renal disease are either insensitive to early dysfunction or have delayed results. Decreased glomerular filtration rate (GFR) indicates renal dysfunction before there is a loss of 50% of functional nephrons. Most tests evaluate global rather than individual kidney function. Dynamic computed tomography (CT) and Patlak plot analysis allows for individual GFR to be tested. Our objectives were to establish a procedure and provide reference values for determination of global GFR in 10 healthy cats using dynamic CT (CTGFR). This method of GFR determination was compared against serum iohexol clearance (SIC). A single CT slice centered on both kidneys and the aorta was acquired every fifth second during and after a bolus injection of iohexol (240 mgI/ml; 300 mgI/kg) for 115 s. Using data from this dynamic acquisition, Patlak plots were obtained, GFR was calculated, and results were compared to global GFR determined by iohexol clearance. The average global CTGFR estimate was 1.84 ml/min x kg (SD = 0.43; range = [1.22, 2.45]). The average global GFR measured using SIC was 2.45 ml/min x kg (SD = 0.58; range = [1.72, 3.69]). GFR measurements estimated by both dynamic CT and SIC were positively associated (estimated Spearman rank correlation coefficient = 0.72; P = 0.0234). The CTGFR method consistently underestimated GFR with a bias of -0.62 (SE = 0.1307) when compared to SIC (P = 0.0011). In healthy cats, CTGFR was capable of determining individual kidney function and appears clinically promising.

Effect of a collateral ligament sparing surgical approach on mechanical properties of equine proximal interphalangeal joint arthrodesis constructs.

OBJECTIVE: To (1) compare the effect of a collateral ligament sparing surgical approach with an open surgical approach on mechanical properties of proximal interphalangeal joint (PIPJ) arthrodesis, and (2) to determine the percentage of articular cartilage surface removed by transarticular (TA) drilling with different diameter drill bits. STUDY DESIGN: Randomized paired limb design. SAMPLE POPULATION: Cadaveric equine limbs (n=76). METHODS: Cadaveric PIPJ were drilled using a 3.5, 4.5, or 5.5 mm drill bit at 80-84° to the dorsal plane to remove articular cartilage and subchondral bone from the distal articular surface of the proximal phalanx (P1) and the proximal articular surface of the middle phalanx (P2). Bone ends were photographed and the percentage of the projected surface area that was denuded of cartilage was measured. PIPJ arthrodesis constructs (3-hole dynamic compression plate [DCP], two 5.5 mm TA screws inserted in lag fashion, medial and lateral to the DCP; DCP-TA) were created using 2 surgical approaches in paired limbs. A conventional open approach was used in 1 limb and a collateral ligament sparing approach used in the other limb. Constructs were tested to failure in single-cycle 3-point dorsopalmar/plantar or lateromedial bending. Maximum load, yield load, and composite stiffness were compared between techniques. RESULTS: The 3.5, 4.5, and 5.5 mm drill bits removed 24±4%, 35±5%, and 45±7% of total PIPJ articular cartilage surface, respectively. Constructs with the collateral ligament sparing approach had significantly greater mean yield load (11.3±2.8 versus 7.68±1.1 kN, P=.008) and mean maximum load (13.5±3.1 versus 10.1±1.94 kN, P=.02) under lateromedial bending. Under dorsopalmar/plantar bending there was no significant difference between surgical approaches. The collateral ligament sparing arthrodesis technique had a shorter surgical time (19±3 minutes) compared with the open technique (31±3 minutes). CONCLUSION: A collateral ligament sparing surgical approach to the PIPJ with removal of articular cartilage by TA drilling and arthrodesis by DCP-TA was faster and stronger in mediolateral bending than arthrodesis constructs created with an open surgical approach. CLINICAL RELEVANCE: Preservation of the collateral ligaments and TA drilling for cartilage removal during PIPJ arthrodesis may be a superior approach to the conventional open approach and warrants clinical evaluation.

Ultrasonographic and magnetic resonance imaging diagnosis of an oropharyngeal wood penetrating injury in a dog.

A 5 yr old female intact English setter with a 17 day history of a penetrating oropharyngeal wound was referred for cervical swelling and pain. Physical examination revealed swelling at the left lateral aspect of the cranial cervical region. Pain was elicited upon flexion, extension, and leftward movement of the neck. Neurologic deficits were not identified. Cervical ultrasonography showed a 0.4 cm × 2.3 cm linear, hyperechoic structure in the soft tissues ventrolateral to the first (C1) and second (C2) cervical vertebrae. MRI demonstrated a linear structure 2 cm in length adjacent to the cranial aspect of C2. The foreign material was isointense to hyperintense on precontrast T1-weighted images, isointense on postcontrast T1-weighted images, and hypointense on T2-weighted images relative to adjacent muscle. Abnormalities within the spinal canal were not identified. Upon surgical exploration, a reed foreign body was identified deep to the serratus ventralis muscle. The patient was normal on follow-up evaluations 4 wk postsurgically.

Fournier's gangrene syndrome in a chimpanzee (Pan troglodytes).

A 37-yr-old male chimpanzee (Pan troglodytes) was evaluated for intermittent diarrhea, scrotal swelling, and lethargy of 2 days duration. Physical examination revealed marked swelling of the scrotum and perineal tissues with mild pitting edema and crepitus. Computed tomography revealed a mixed gas and soft-tissue density extending from the caudal ventral subcutaneous tissues caudally to the scrotum and perineal tissues. Surgical exploration and castration were performed to establish drainage, and culture revealed a polymicrobial infection. A diagnosis of scrotal and fascial plane abscessation consistent with Fournier's gangrene was made. Although castration with open drainage was performed, the animal died 36 hr after surgery. Postmortem examination and histopathology revealed necrotizing fasciitis of the penis, vaginal tunic, and subcutaneous perineal and perianal tissues.

Comparing types of digital capture.

Many digital radiography systems are available. These include both cassette-based and cassette-less systems. Understanding the pros and cons of each system is important prior to purchase.

Digital radiographic artifacts.

Artifacts in radiography can be detrimental to interpretation by decreasing visualization or altering the appearance of an area of interest. Digital radiographs (DRs) have their own unique artifacts, and recognition of these artifacts is important to prevent misinterpretation and help identify the cause. A DR artifact can be categorized according to the step during which it was created. The major categories are preexposure, exposure, postexposure, reading, and workstation artifacts. Understanding the cause of artifacts and method of resolution is paramount in acquiring high-quality digital images.

PACS and image storage.

Storage and retrieval of digital images is an integral component of any digital imaging system. A picture archiving and communication system (PACS) includes hardware and software that allows for display, storage, retrieval, and communication functions. PACS software allows for manipulation of the images to enhance interpretation by way of changes in contrast, brightness, magnification, and measurements, among others. Digital images for medical imaging should be in the digital imaging communications in medicine file format. This specified format allows for interconnectivity between imaging systems from different vendors and is important to ensure appropriate security. A hospital information system or radiology information system can be used to tie the patient record with the digital images in a paperless medical record system.

Magnetic resonance imaging of bone marrow in the pelvis and femur of young dogs.

The purpose of this study was to determine the magnetic resonance (MR) imaging characteristics of bone marrow in the pelvis and femur of normal, young dogs. Six greyhounds were imaged at 4, 8, 12, and 16 months of age. Sagittal images of the femur and dorsal images of the pelvis were obtained with T1-weighted, fast spin echo (FSE) T2-weighted, and short tau (T1) inversion recovery (STIR) sequences. On T1-weighted images areas with high signal intensity, similar to fat, included the femoral heads, mid-diaphysis of the femur, femoral condyles, and the body of the ilium. T2-weighted images were characterized by uniform intermediate signal intensity (less than fat, but greater than muscle) in the femoral head, high signal intensity, similar to fat, in the mid-diaphysis of the femur and ilial body, and intermediate to high signal intensity in the femoral condyle. By 16 months high signal intensity was seen in the diaphysis and distal metaphysis on both T1- and T2-weighted images. On STIR images the femoral head had intermediate to low signal intensity, compared with muscle. The mid-diaphysis of the femur was of low signal intensity, similar to fat, and the body of the ilium had mixed signal intensity at all ages. The femoral condyle had inhomogenous, intermediate to low signal intensity at 4 months, but was of uniform low signal intensity at 8-16 months.

Artifacts in digital radiography.

Digital radiography is becoming more prevalent in veterinary medicine, and with its increased use has come the recognition of a number of artifacts. Artifacts in digital radiography can decrease image quality and mask or mimic pathologic changes. They can be categorized according to the step during which they are created and include preexposure, exposure, postexposure, reading, and workstation artifacts. The recognition and understanding of artifacts in digital radiography facilitates their reduction and decreases misinterpretation. The purpose of this review is to name, describe the appearance, identify the cause, and provide methods of resolution of artifacts in digital radiography.

Magnetic resonance imaging of the femoral head of normal dogs and dogs with avascular necrosis.

The purpose of this study was to describe the appearance of the femoral head of normal, young, small breed dogs, and dogs with avascular necrosis using low-field (0.3 T) magnetic resonance (MR) imaging. Images of the femoral heads were obtained in the dorsal plane, and included T1-weighted spin-echo, T2-weighted fast spin-echo, fast spin echo-inversion recovery, and fluid attenuated inversion recovery pulse sequences. MR imaging features of the asymptomatic femoral heads and necks included uniform high signal intensity compared with muscle on T1- and T2-weighted images. There was either uniform enhancement or no enhancement on postcontrast T1-weighted images. The MR imaging findings of dogs affected with avascular necrosis differed from those of asymptomatic dogs. Typically, the affected dogs had inhomogeneous intermediate to low-signal intensity within the femoral head and neck compared with muscle on T1-weighted images, inhomogeneous enhancement of the femoral head and/or neck on postcontrast T1-weighted images, and inhomogeneous low- to high- signal intensity within the femoral head and neck on T2-weighted images.

The clinical utility of the right lateral intercostal ultrasound scan technique in dogs.

When performing abdominal ultrasonography in dogs, the right aspect of the liver, porta hepatis, right kidney, right adrenal gland, pancreas, and duodenum are often not fully visible from a ventral, or subcostal, approach. The right lateral intercostal plane is an alternative approach that allows evaluation of these structures. This report provides multiple case examples that demonstrate the sonographic anatomy via the right intercostal approach. Other cases are included to demonstrate indications for this approach. Animals in which the right intercostal approach may prove most useful include large- and giant-breed dogs; deep-chested dogs; dogs with gas distention of the stomach, duodenum, and colon; dogs with microhepatia; and those with abdominal effusion and pain.

Comparison of digitized and direct viewed (analog) radiographic images for detection of pulmonary nodules.

The purpose of this study was to compare direct (analog) viewing of thoracic radiographs with digitized images obtained with a radiographic scanner and seven digital cameras for detection of pulmonary nodules. Direct viewing of the analog radiographs was significantly better than all digitized methods (P<0.01). Significant variations exist between the radiographic scanner and the digital cameras. The scanner (Kodak LS75) was significantly better than the Kodak DC 4800 and the Sony DSC-707 cameras (P<0.05). The Nikon 995, Canon EOS-D30, and Ricoh i500 were significantly better than the Sony DSC-707 (P<0.05). There was no significant difference between the Kodak DC 3800, Kodak DC 4800, and the Sony DSC-707. For pairwise comparison of raters (when evaluating the radiographs individually compared with the consensus), the raters matched the consensus rating from 85% to 92% with no significant difference between raters.

Correlation of results of pulmonary computed tomography and pathologic findings in mice with Pasteurella-induced pneumonia.

OBJECTIVE: To determine correlation between results of computed tomography (CT) versus pathologic examination for determining the volume percentage of affected lung in mice experimentally infected with Pasteurella pneumotropica. ANIMALS: 30 adult mice. PROCEDURE: After helical CT scans on day 0, mice were inoculated intranasally with P. pneumotropica. Repeat CT scans were performed on days 1, 2, 3, 4, 6, 8, 10, and 13. Regions of interest (affected areas) were manually drawn on the CT images, and percentage volume of normal lung was calculated by use of 3 methods: first-day volume, largest volume, and last-day volume. Three mice were euthanatized for pathologic evaluation after each scan day. The lungs were examined with a dissection microscope, and lesion scores were assigned on the basis of percentage volume of pneumonia. Correlation coefficients comparing results of the 3 CT methods with results of gross examination were calculated. RESULTS: Lung abnormalities were detected via dissection microscopy by postinfection day 2 and via CT by days 2 or 3. Correlation coefficients for the 3 CT methods of analysis, compared with pathologic findings, were 0.7 via first-day lung volume, 0.8 via largest lung volume, and 0.8 via last-day lung volume. CONCLUSIONS AND CLINICAL RELEVANCE: Results of CT correlated well with results of dissection microscopy for estimating percentage volume of lung affected by pneumonia in mice experimentally infected with P. pneumotropica. This method may be useful for longitudinal studies of pneumonia in mice.