Development and feasibility of new cardiac measurement method using vertebral heart area ratio in dogs.

The vertebral heart scale (VHS) is the most common method used for the objective evaluation of heart size, however, VHS cannot evaluate the entire heart area. This retrospective study aimed to evaluate the development and feasibility of vertebral heart area ratio (VHAR=heart area/the fourth thoracic vertebra [T4] body area) as a new cardiac measurement method. A total of 125 dogs considered without clinical heart abnormalities in the pre-anesthetic examination, measurements of the VHS and VHAR using thoracic radiography were compared with computed tomography measurements of the vertebral cardiac volume ratio (VCVR=cardiac volume/T4 body volume) and investigate whether the VHAR values differed between observers. The mean cardiac and T4 body volumes were 116.99 ± 108.07 cm3 and 0.92 ± 0.91 cm3, respectively. The mean values of observers 1 and 2 were 9.9 ± 0.7 v (VHS), 42.64 ± 27.94 cm2 (heart area), and 1.37 ± 0.96 cm2 (T4 body area). Intraclass coefficients were the highest for the heart area, followed by the T4 body area and VHS. The VHAR showed a moderate correlation with VHS in observers 1 (r=0.671) and 2 (r=0.633). The VCVR showed a more positive correlation with VHAR (r=0.573) than with VHS (r=0.426). These results indicated that VHAR could be used as a complement to VHS for heart size measurement, and the high degree of observer agreement for the measurements indicated the measurement reproducibility of VHAR.

Radiographic and computed tomographic evaluation of tracheal diameter and length in kittens.

OBJECTIVE: To measure the tracheal diameter and length in kittens using radiography and CT and to evaluate the concordance between measurements obtained with these 2 modalities. ANIMALS: 15 kittens with an estimated age of 12 weeks and mean body weight of 1.49 kg. METHODS: Radiographic and CT images were retrospectively evaluated to measure tracheal lengths and diameters. Tracheal diameters were measured at 5 different sites (A [at the level of the C2-3 intervertebral disk space], B [at the level of the C4-5 intervertebral disk space], C [at the cranial end of the manubrium sterni], D [at the level of the second rib], and E [1 cm cranial to the carina]) along the trachea. The cross-sectional area and transverse and vertical diameter ratios were calculated for each measurement site. RESULTS: The cross-sectional area was largest at site A and decreased from site C to site E. Based on the vertical diameter ratio, the tracheal shape was most circular at sites A and E, whereas from sites B to D, it was elliptical. The vertical diameters of the trachea on radiography and CT did not differ statistically significantly. However, the tracheal length measured on radiography was approximately 6 mm longer than that measured on CT (P < .05). CLINICAL RELEVANCE: Using the first rib as an anatomical reference, the placement of a cuffed endotracheal tube is recommended in kittens. In emergency situations, regression equations based on body weight may be helpful in predicting tracheal diameters.

Subcutaneous emphysema and pneumomediastinum following orbital blowout pathological fracture in a cat with nasal lymphoma: a case report.

BACKGROUND: Subcutaneous emphysema and pneumomediastinum are rare complications associated with orbital blowout pathological fracture. CASE PRESENTATION: A 7-year old, castrated male Abbysinian cat presented with anorexia, lethargy, nausea, eyelid swelling, nasal discharge, and sneezing. Based on the clinical and diagnostic work-up, the cat was diagnosed with T cell high-grade nasal lymphoma associated with orbital pathological fracture due to the tumour invasion. After chemotherapy, the cat showed massive subcutaneous emphysema from frontal region to abdomen and pneumomediastinum due to orbital blowout pathological fracture. As the nasal mass decreased in volume; the air had moved from the maxillary sinus to the subcutaneous region and the mediastinum through fascial planes in the head and neck region. CONCLUSIONS: This is a first case report of a massive subcutaneous emphysema and pneumomediastinum due to an orbital blowout pathological fracture following chemotherapy in feline nasal lymphoma in veterinary medicine.

Safety assessment of a three-dimensional-printed autologous omentum patch: An application on the kidneys as a new treatment approach.

Recently, the field of regenerative medicine has made great strides in the development of new treatments for various organ dysfunctions. One of the most promising new approaches is the use of three-dimensional (3D) printing and autologous tissues. In this study, we evaluated the safety of a 3D-printed autologous omentum patch to kidneys using large animals. A total of seven micropigs underwent transplantation of the 3D-printed autologous omentum patch. Twelve weeks after transplantation, the safety was evaluated by measuring body weight, blood, and the renal resistive index. In addition, biopsy samples were histologically analyzed. The results showed no surgical complications, renal functional hematological changes, or inflammatory responses. Therefore, this study provides important insights into direct therapy to kidneys with a 3D-printed patch made of autologous tissue. Furthermore, it has the potential for the development of new therapies for various organ dysfunction.

Measurement of tracheal diameters using ultrasonography versus computed tomography in Beagle dogs.

OBJECTIVE: To compare ultrasonography with computed tomography (CT) for assessment of tracheal diameter as a feasibility study for endotracheal tube selection. STUDY DESIGN: Prospective study. ANIMALS: A total of nine Beagle dogs with a median (interquartile range) weight of 7.4 (7.2-7.7) kg. METHODS: Tracheal diameter measurements were obtained at two locations: 1 cm proximal to caudal border of the cricoid cartilage (sublaryngeal; SL) and dorsal to above cranial border of the manubrium (thoracic inlet; TI). For CT, dogs were anesthetized with propofol and sevoflurane, in sternal recumbency, and measurements obtained after controlled ventilation-induced apnea and the endotracheal tube cuff was deflated. Transverse diameter, right and left 45° oblique diameters were measured. For ultrasonography, unsedated dogs were standing with slight neck extension, and images obtained in ventrodorsal, 45° right and left oblique ways after expiration. Diameters between the tracheal lumen mucosal borders were measured. The degree of agreement between the tracheal diameters measured at SL and TI locations with CT (TDCT-SL and TDCT-TI) and ultrasonography (TDUS-SL and TDUS-TI) was verified using the Bland-Altman method. RESULTS: The agreement between the measurements obtained with CT and ultrasonography was revealed by Bland-Altman analyses, although ultrasonography tended to slightly underestimate the tracheal diameter. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonography can be applied for tracheal diameter measurement. Although further studies are required, an endotracheal tube selection method, using ultrasonography, could be proposed.

Retrospective analysis of efficacy and safety of oral paclitaxel for treatment of various cancers in dogs (2017-2021).

BACKGROUND: In humans, several safety evaluations have shown minimal adverse events with oral paclitaxel; however, its therapeutic efficacy and safety has not been well established in dogs with various cancers. OBJECTIVES: We aimed to retrospectively evaluate the efficacy and safety of oral paclitaxel in dogs with various cancers. METHODS: Twenty-one dogs diagnosed with various cancers were administered several doses of oral paclitaxel three times a month (group 1) or six times a month (group 2). RESULTS: The overall response rate was 6.25% (6.25%, complete response; 56.25%, stable disease; 37.5%, progressive disease) in dogs for which the treatment response could be evaluated. The median overall survival (OS) and progression-free survival (PFS) were 74 and 60.5 days, respectively. Regardless of the administration group, differences in OS and PFS of the two groups did not reach statistical significance. Most dogs tolerated the treatment regimen well, and although minor adverse events were observed in some dogs, they recovered after temporary drug discontinuation, dose reduction or symptomatic treatment. There was no significant difference in the prevalence of adverse events between the two groups. CONCLUSIONS: Based on the observed responses in certain types of cancers and the minimal adverse events, the study findings supported the efficacy and safety of oral paclitaxel administration in dogs. Thus, oral paclitaxel could play a role in the management of cancer in dogs.

Unusual case of pleural effusion caused by amlodipine in a dog with systemic hypertension.

OBJECTIVE: The aim of this report is to document the case of a dog that developed pleural effusion as a potential side-effect to the administration of a high-dose of amlodipine. CASE SUMMARY: A Yorkshire terrier dog (13-year-old, castrated male, 4.5 kg) presented with severe systemic hypertension (>200 mmHg), hyperkalaemia, and acute pancreatitis. The dog had hyperadrenocorticism, chronic valvular heart disease, chronic kidney disease, and cerebellar infarction as underlying diseases. Additionally, the dog had laboured breathing and tachypnoea during hospitalization. Screening examinations revealed a pleural effusion (pure transudate) for which hypoalbuminemia and thromboembolism were ruled out as the causes. Therefore, the adverse drug event of an anti-hypertensive drug (amlodipine) was tentatively diagnosed. CONCLUSIONS: Pleural effusion resolved within 24 h of reducing the dosage of amlodipine. Hence, the dog was diagnosed with amlodipine-induced pleural effusion. Rarely, amlodipine can cause pleural effusion after high-dose administrations in humans, but only two cases of peripheral edema have been reported in animals. If pleural effusion occurs in hypertensive patients administered amlodipine, it should be considered as the potential cause.

Translocation of the conus medullaris during dynamic lumbosacral magnetic resonance imaging in dogs.

OBJECTIVE: To investigate the change in the lumbosacral angle (ΔLSA) and conus medullaris (CM) displacement in healthy dogs undergoing dynamic MRI with changes in the posture of their pelvic limbs from neutral posture to flexion or extension posture and to evaluate for potential correlation between ΔLSA and CM displacement. ANIMALS: 9 healthy adult Beagles. PROCEDURES: Dogs underwent dynamic MRI with their pelvic limbs positioned in neutral, flexion, and extension postures. From T2-weighted sagittal midline plane MRI images, 2 observers measured the lumbosacral angle and CM location in duplicate for each posture for each dog. Intra- and interobserver agreement was assessed, and the Spearman rank correlation coefficient (ρ) was used to assess for potential correlation between ΔLSA and CM displacement for changes in pelvic limb posture from neutral to flexion or extension. RESULTS: Overall, the mean ΔLSA and CM displacement for changes in posture were 23° and 9.09 mm (caudal displacement) for the change from neutral to flexion posture, 8.4° and -2.5 mm (cranial displacement) for the change from neutral to extension posture, and 32.2° and 11.64 mm (caudal displacement) for the change from extension to flexion posture. The ΔLSA strongly correlated (ρ = 0.705; 95% CI, 0.434 to 0.859) with displacement of the CM. CONCLUSIONS AND CLINICAL RELEVANCE: The use of dynamic MRI, compared with conventional MRI, will better help to characterize clinically normal and abnormal features of the lumbosacral region of the vertebral column and associated spinal cord during postural changes. Further, when limited translocation of the CM is evident on dynamic MRI, veterinarians should suspect underlying lumbosacral pathophysiologic processes or anatomic abnormalities.

Severe hydrocephalus in a raccoon dog (Nyctereutes procyonoides).

Hydrocephalus is one of the most common central nervous system malformations in domestic dogs, yet they are poorly documented and studied in wild carnivoran mammals. A pup of raccoon dog (Nyctereutes procyonoides) was rescued and brought to Wildlife Center. The pup showed generalized ataxia, a domed skull, and an open bregmatic fontanelle. Ultrasound and MRI showed severe enlargement of the lateral ventricle with the loss of septum pellucidum resulting in a single large ventricle and cervical syringohydromyelia. Although treatment was attempted, the animal was euthanized due to poor prognosis. At necropsy, macroscopic findings were identical to the diagnostic imaging, where marked enlargement of the calvarium, and attenuated gyri and sulci were observed. Finally, hydrocephalus was confirmed. Here, we describe a case of hydrocephalus in a raccoon dog (Nyctereutes procyonoides).

Antegrade and retrograde CT urethrography with virtual urethroscopy in a dog with urethral narrowing after bilateral triple pelvic osteotomy.

An 8-month-old, castrated male Golden Retriever was unable to urinate without catheterization after a single-session bilateral triple pelvic osteotomy. To determine the cause, a retrograde urethrography was performed, but the results were equivocal. Antegrade (voiding by abdominal compression with heavy material) and retrograde CT urethrography were performed with virtual urethroscopy and revealed that the urethral diameter was narrowed near the pubic bone remnants due to pelvic canal narrowing. After corrective surgery, the patient was able to urinate normally. A combination of antegrade and retrograde CT urethrography with virtual urethroscopy was helpful for guiding surgical decision-making in this patient.

The urethra of healthy female dogs can be normally narrowed due to the urethral flexure in retrograde CT urethrography.

Quantitative analysis of urethral size in male dogs by retrograde CT urethrography using a power injector is a recently reported technique. The aim of the current, prospective, analytical study was to apply the same method to six, healthy, intact female Beagle dogs. The proximal (P < .0001) and middle (P = .0010) urethral volumes significantly differed between the empty and distended bladder states, although no significant difference was observed in the distal volume (P = .0971). Unlike male dogs, female dogs showed two patterns of the urethral course: a straight urethra and urethral flexure. The urethral flexure was always related to intrapelvic position of the urinary bladder, and the more caudal the location of the vesicourethral junction beyond the pecten of the pubic bone, the more marked the appearance of the urethral flexure. Analysis of the urethral diameter at five sites (adopted from the previous radiographic study) was performed, and the urethral diameter showed a significant difference between the empty and the distended bladder states at sites 1 (vesicourethral junction, P < .0001), 2 (P < .0001), and 3 (P = .0244). However, there were no significant differences at sites 4 (P = .2516) and 5 (inflatable retention bulb, P = .1260). The urinary bladder may be in part intrapelvically located in clinically healthy female dogs, and urethral flexure and urethral narrowing can result from the intrapelvic location of the bladder. Narrowing of the urethra should be interpreted with caution when the pelvic bladder is identified.

Retrograde CT urethrography using a power injector quantitatively reveals effects of bladder distension on urethral size in healthy male Beagle dogs.

Quantitative analysis of the normal retrograde urethrogram is well reported in radiography, but studies on CT urethrography are lacking. Recently, a method of retrograde CT urethrography using a power injector was described. The purpose of the current, prospective, analytical study was to quantify the urethral size of five, healthy, intact, male Beagle dogs using retrograde CT urethrography and a power injector. With the injection rate of the power injector set at 0.3 mL/s, 1 mL/kg of diluted contrast medium (15 mg I/mL) was injected, and a CT examination was performed. The state of the initial urethrogram taken was defined as "empty bladder." The same procedures were repeated with the injection of an additional 1 mL/kg of diluted contrast medium until the ureteral reflux was seen (distended bladder). There was a significant difference in volumes between the empty and distended bladder, but the membranous urethra showed the least difference (P = .0044) among the three regions (P < .0001 for the prostatic and penile urethra). Urethral diameters at six sites were measured from sagittal images, and the sites of measurements were adopted from the earlier radiographic studies. The most significant difference in the urethral diameters between the empty and distended bladder occurred at the cranial and middle prostatic urethra (P < .0001). The results of this study can be useful for interpreting the results of retrograde CT urethrography. Care must be taken when narrowing is suspected at the prostatic urethra, and if necessary, further distension of the urinary bladder should be tried.

Feasibility and Reliability of Two-Dimensional Shear-Wave Elastography of the Liver of Clinically Healthy Cats.

Given the broad overlap of normal and abnormal liver tissue in the subjective evaluation of the liver in conventional B-mode ultrasonography, there is a need for a non-invasive and quantitative method for the diagnosis of liver disease. Novel two-dimensional shear-wave elastography (2-D SWE) can measure tissue stiffness by propagation of the shear wave induced using acoustic radiation force impulse in real time. To the best of our knowledge, two-dimensional shear-wave measurement of the liver in cats has not been reported to date. This study assessed the feasibility, reliability, normal values, and related influencing factors of 2-D SWE for assessment of the feline liver without anesthesia and breath-holding. Two-dimensional shear-wave ultrasonography was performed by two evaluators at the right and left sides of the liver. Twenty-nine client-owned clinically healthy adult cats were included. The means and standard deviations for the shear-wave speed and stiffness in the right liver were 1.52 ± 0.13 m/s and 6.94 ± 1.26 kPa, respectively, and those for the left liver were 1.61 ± 0.15 m/s and 7.90 ± 1.47 kPa, respectively. Shear-wave speed (P = 0.005) and stiffness (P = 0.002) were significantly lower in the right liver when compared to the left. The intraclass correlation value for liver stiffness was 0.835 and 0.901 for the right and left liver, respectively, indicating high interobserver agreement. Age, weight, body condition score (BCS), gabapentin administration, and measurement depths were not significantly correlated with liver stiffness or elastography measurements (P > 0.05). Our findings suggest that 2-D SWE measurements of the liver are not influenced significantly by age, weight, or BCS and can be reliably performed without anesthesia and breath-holding in cats. The values determined here can help form the basis for reference elastography values for evaluation of the feline liver.

Computed tomographic lymphangiography of the thoracic duct by subcutaneous iohexol injection into the metatarsal region.

OBJECTIVE: To evaluate the efficacy of subcutaneous iohexol injection into the metatarsal region for thoracic duct lymphangiography in dogs and to determine the minimum effective dose. STUDY DESIGN: Experimental study and clinical report. ANIMALS: Five healthy beagle dogs and one dog with chylothorax. METHODS: For the experimental study, iohexol was injected subcutaneously into the metatarsal region of five dogs at three doses (0.5, 0.75, and 1 mL/kg), and the injection sites were massaged gently. Computed tomography (CT) was performed 1, 3, 5, 7, 10, 15, and 20 minutes after iohexol injection. Subjective quality was assessed, and Hounsfield unit values were measured at several regions of interest (T1, T4, T8, T13, and L3). In the dog with chylothorax, iohexol (1.0 mL/kg) was injected into the right metatarsal region prior to CT. RESULTS: The thoracic duct was visualized and enhanced by contrast in all dogs after injection of 0.75 and 1.0 mL/kg of iohexol, and in two dogs after injection of 0.5 mL/kg at 3, 5, and 7 minutes. The thoracic duct was gradually attenuated with increasing doses of iohexol. In the dog with chylothorax, the entire thoracic duct was well enhanced and dilated, and tortuous cranial mediastinal lymphatics were detected. CONCLUSION: The thoracic duct was visualized when at least 0.75 mL/kg of iohexol was injected subcutaneously into the metatarsal region of dogs. CLINICAL SIGNIFICANCE: Subcutaneous injection of iohexol into the metatarsal region offers a simple alternative to conventional thoracic duct lymphangiography.

Effect of catheter diameter and injection rate of flush solution on renal contrast-enhanced ultrasonography with perfluorobutane in dogs.

OBJECTIVE: To assess effects of catheter diameter and injection rate of flush solution (saline [0.9% NaCl] solution) on renal contrast-enhanced ultrasonography (CEUS) with perfluorobutane in dogs. ANIMALS: 5 healthy Beagles. PROCEDURES: CEUS of the kidneys was performed by IV injection of contrast medium (0.0125 mL/kg) followed by injection of 5 mL of saline solution at rates of 1, 3, and 5 mL/s through a 20-gauge or 24-gauge catheter; thus, CEUS was repeated 3 times for each catheter diameter. Time-intensity curves were created for regions of interest drawn in the renal cortex and medulla. Repeatability was determined by calculating the coefficient of variation (CV). Statistical analysis was used to assess whether perfusion variables or CV of the perfusion variables was associated with catheter diameter or injection rate. RESULTS: Perfusion variables did not differ significantly between catheter diameters. Time to peak enhancement (TTP) in the renal cortex was affected by injection rate, and there were significantly lower values for TTP at higher injection rates. The CEUS variables with the lowest CVs among injection rates were TTP for the renal cortex; the CV for TTP of the renal cortex was the lowest at an injection rate of 5 mL/s. CONCLUSIONS AND CLINICAL RELEVANCE: Use of a 24-gauge catheter did not alter CEUS with perfluorobutane; therefore, such catheters could be used for CEUS of the kidneys of small dogs. Moreover, a rate of 5 mL/s is recommended for injection of flush solution to obtain greater accuracy for renal CEUS in Beagles.

Effects of airway pressure on contrast enhancement and diameter of the pulmonary artery in healthy dogs as determined by use of computed tomography angiography.

OBJECTIVE: To evaluate effects of airway pressure on contrast enhancement and diameter of the pulmonary artery and determine the optimal airway pressure for pulmonary CT angiography in dogs. ANIMALS: 8 healthy Beagles. PROCEDURES: Thoracic CT was performed at end-expiration (0 cm H2O) and 2 positive-pressure end-inspirations (10 and 20 cm H2O). Attenuation curves of enhancement for the sinus of the pulmonary trunk artery were obtained by use of a bolus technique. Contrast medium (300 mg of I/kg) was administered IV, and CT imaging began at the time of peak enhancement. At each pressure, time to peak enhancement, ratio of blood flow from the caudal vena cava to the right side of the heart (KCdVC), and enhancement characteristics and diameter changes of the pulmonary artery were evaluated. RESULTS: All dogs had a significant delay for time to peak enhancement in the sinus of the pulmonary trunk artery as airway pressure increased. The KCdVC progressively increased as airway pressure increased, and there was low contrast enhancement and increased pulmonary artery filling defects at 20 cm H2O. All pulmonary arteries had marked increases in diameter as pressure increased. Arterial distensibility in the gravity-dependent cranial lung region was greater than that in the gravity-independent caudal lung region at the 2 positive-pressure end-inspirations. CONCLUSIONS AND CLINICAL RELEVANCE: Airway pressure affected time to peak enhancement, KCdVC, contrast enhancement, and pulmonary artery diameter. Results suggested that 10 cm H2O could be an optimal pressure for evaluation of the pulmonary artery of dogs by use of CT angiography. (Am J Vet Res 2019;80;756-763).