Objective: To evaluate the effects of reduced kVp and reduced iodinated contrast volume on radiation dose and image quality in canine abdominal CT. Methods: A phantom study (0%–10% iodine dilutions) at 120, 100, and 80 kVp quantified the relationship between iodine concentration and CT attenuation. Eight healthy Beagle dogs underwent multiphase abdominal CT at 120, 100, and 80 kVp (1-week intervals) with weightbased contrast volumes adjusted using phantom-derived slope ratios. Radiation output (CTDIvol , dose-length product) and quantitative image quality (attenuation, background noise, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]) were assessed, along with blinded qualitative scoring by 2 readers. Results: Compared with 120 kVp, CTDIvol decreased by 41% at 100 kVp and 74% at 80 kVp, with similar proportional decreases in dose-length product. Lower kVp increased iodinerelated attenuation, permitting iodine-dose reductions (17% at 100 kVp; 34% at 80 kVp).Quantitative noise increased and SNR decreased at 80 kVp, particularly in delayed-phase images; qualitative noise scores were significantly worse at 80 kVp, whereas overall qualitative image quality did not differ across protocols. Conclusions and Relevance: In dogs, a 100 kVp protocol reduced radiation output and iodine dose while maintaining diagnostic image quality, supporting 100 kVp as a practical optimization strategy for clinical abdominal CT.

This study aimed to evaluate the usefulness of anatomic M-mode (AMM) in 31 healthy cats. We compared cardiac dimensions and function using two-dimensional (2D) mode, AMM, and conventional M-mode (CMM). We used 2D as the standard and evaluated the agreement among 2D, AMM, and CMM measurements. In healthy cats, AMM, rather than CMM, measurements of IVSd/s, LVDd/s, and LVFWd were acceptable for reliability. Since the diagnosis of HCM is based on thickness of IVSd and LVFWd, AMM has potential to be more useful than CMM as a diagnostic tool for echocardiographic measurement in cats.

Objective: The purpose of this study was to retrospectively analyze the trends in RT among dogs and cats treated at the S Animal Cancer Center in Korea from 2020 to 2023. Methods: A retrospective analysis was conducted on 376 animals (308 dogs and 68 cats) receiving RT for various tumors. Data collected included species, breed, sex, age, weight, tumor location, tumor type, RT protocols, and concurrent treatments. Results: The number of patients receiving RT increased from 59 in 2020 to 120 in 2023, reflecting a 103.4% increase over the study period. Sinonasal, intracranial, oral, genitourinary, and skin tumors were the most common, with stereotactic RT being most commonly used for sinonasal and intracranial tumors. Of the patients, 175 (46.5%) received RT alone, 96 (25.5%) with chemotherapy, 64 (17%) with surgery, and 41 (10.9%) with both surgery and chemotherapy. Thirty-one patients (8.2%) underwent multiple RT sessions, primarily for sinonasal tumors (11 cases). Conclusions and Relevance: This study provides the first systematic analysis of RT use in companion animals in Korea and establishes a foundational dataset for future work in veterinary radiation oncology. The findings highlight the growing clinical use of RT and underscore the need for further research to optimize treatment protocols and evaluate patient outcomes in Korean veterinary oncology.

A 4-month-old intact male Sapsaree dog was referred due to a history of postprandial regurgitation following consumption of solid food. Thoracic radiography revealed focal leftward displacement of the thoracic trachea at T1 to T4 vertebrae levels. Barium contrast radiography revealed focal dilation of the cranial thoracic esophagus at the heart base level. Persistent right aortic arch (PRAA) with an aberrant left subclavian artery branching from the patent ductus arteriosus was diagnosed by computed tomography angiography (CTA). Although barium contrast radiography can presumptive diagnose PRAA, CTA should be considered for identifying additional vascular anomalies, specific types, and surgical planning.

A 3-year-old spayed female Russian blue cat was presented for dyspnea, nasal discharge, and stertorous breathing. Plain thoracic radiography revealed no specific findings. Computed tomography (CT) was performed to differentiate upper airway tract disorders. It revealed the presence of an iso-attenuating mass measuring 10.0 × 7.9 × 15.6 mm, with mild homogeneous contrast enhancement occupying the rostral nasopharynx. The mass was surgically debulked via a longitudinal incision in the soft palate. Histopathological and immunohistochemistry analysis of the surgically excised mass revealed CD3–/ CD79a+ B cell lymphoma with an incomplete margin. The patient underwent hypofractionated radiation therapy, receiving a total of 36 Gray (Gy) in 6 Gy fractions over a six-week period. A follow-up CT examination was performed after 27 months of irradiation and the patient was confirmed to have achieved a complete response. There were no complications related to irradiation. The patient was alive for 40 months without recurrence. This study suggests that hypofractionated radiation therapy combined with surgical debulking could be considered as a treatment option for feline nasopharyngeal lymphoma.

A 13-year-old castrated male mixed-breed dog presented for a health screening with a small nodule on the left hindlimb, which was revealed to be a mast cell tumor. A CT scan was performed to evaluate the mast cell tumor, and it incidentally revealed a well-marginated, fluid-attenuating, non-contrast enhanced mass in the deep ventral region of the left lower neck. Ultrasonography confirmed a well-capsulated mass with a cranio-ventrally protruding lesion extending into sternohyoid muscles. The outer layer of the mass had a hypoechoic thick wall and the internal parenchyma contained hyperechoic foci and multiple hyperechoic parallel lines. The mass was surgically resected. Histopathological examination confirmed a dermoid cyst characterized by cornifying squamous epithelial cells, keratinaceous debris, and hair shaft fragments. The dog showed no signs of recurrence or additional abnormalities three months post-surgery. This report highlights the importance of considering dermoid cysts in the differential diagnosis of neck masses on imaging examinations using CT or ultrasonography.

A 13-year-old male neutered Miniature Pinscher presented with coughing and dyspnea. The dog had been coughing for the past 4 weeks. The patient had mild dehydration on physical examination, and muffled heart sounds were detected. Thoracic radiographs revealed pleural effusion, which was consistent with chylous effusion based on cytological and biochemical evaluations. Computed tomography (CT) lymphangiography, which was performed via intrametatarsal pad injection, revealed no evidence of thoracic duct rupture or obvious leakage. On CT angiography (CTA), an intraluminal filling defect was identified in the cranial vena cava (CrVC). CrVC thrombosis with secondary chylothorax was diagnosed based on CT lymphangiography and CTA. Clopidogrel, rivaroxaban, and recombinant tissue-plasminogen activator were prescribed. The follow-up CTA, 4 months after diagnosis, revealed a decrease in the thrombus, and no pleural effusion was identified. Although CrVC thrombosis is an uncommon presentation in veterinary patients, thrombus in the CrVC should be considered as a differential diagnosis of chylothorax in dogs. CT lymphangiography and CTA could be helpful in identifying and differentiating the underlying etiologies of chylothorax.

A 10-year-old spayed female Poodle was referred for blindness. On ophthalmic examination, loss of bilateral ocular pupil light reflex, visual loss, and right retinal detachment were confirmed at a local hospital. Magnetic resonance imaging (MRI) of the brain was performed to identify the optic nerve, optic chiasm, and brain disease. A sessile mass centered on the region of the optic chiasm was identified. The mass had iso- to hypointense on fluid-attenuated inversion recovery and T2-weighted images and mildly hypointense on T1-weighted images compared to the gray matter, with strong contrast enhancement. Peripheral edema was also identified. Computed tomography (CT) brain perfusion was performed to obtain additional hemodynamic information about the patient using a multislice CT. CT perfusion showed that the cerebral blood volume in the left temporal lobe region (13.4 ± 1.6 mL/100 g) was decreased relative to the contralateral region (19.9 ± 0.3 mL/100 g). The patient showed decreased appetite and consciousness one week after the CT scan with clinical symptoms worsened. The patient had seizure, tetraparesis, and loss of consciousness. It was euthanized one month later at the request of the owner. This report suggests that CT brain perfusion can provide additional hemodynamic information such as insufficient brain perfusion in sellar region tumor which can help assess potential complications and prognosis and plan treatment.

Background: Bone subtraction computed tomography angiography (BSCTA) is a useful alternative technique for improving visualization of vessels surrounded by skull bone.However, no studies have compared computed tomography angiography (CTA) and BSCTA for improving the visibility of canine cerebral blood vessels. Objectives: To evaluate the potential benefit of BSCTA for better delineation of brain arteries of the circle of Willis (CoW) in dogs by comparing BSCTA with non-subtraction computed tomography angiography (NSCTA). Methods: Brain CTA was performed for nine healthy beagle dogs using a bolus tracking method with saline flushing. A total dose of 600 mgI/kg of contrast agent with an iodine content of 370 mgI/mL was injected at a rate of 4 ml/s. Bone removal was achieved automatically by subtracting non-enhanced computed tomography (CT) data from contrast CT data. Five main intracranial arteries of the CoW were analyzed and graded on a scale of five for qualitative evaluation. Results: Scores of basilar artery, middle cerebral artery, and rostral cerebral artery in the BSCTA group were significantly higher than those in the NSCTA group (p = 0.001, p = 0.020, and p < 0.0001, respectively). Scores of rostral cerebellar artery (RcA) and caudal cerebral artery (CCA) did not differ significantly between the two groups. However, scores of RcA and CCA in the BSCTA group were higher than those in the NSCTA group. Conclusions BSCTA improved visualization of intracranial arteries of the CoW with close contact to bone. Thus, it should be recommended as a routine scan method in dogs suspected of having brain vessel disease.

A 5-year-old castrated male domestic shorthair cat was referred for further investigation of pulmonary nodules incidentally detected on thoracic radiographs. Thoracic radiographs identified ill-defined soft tissue opacity nodules with small faint mineral opacity. Thoracic computed tomography (CT) revealed that bronchial dilation and bronchial wall thickening in bilateral cranial and accessory lung lobes. Round to ellipsoid mineralized concretions were found embedded in the intrabronchial soft tissue attenuation material. Based on radiography, CT, and cytology, the patient was tentatively diagnosed as having broncholithiasis with chronic bronchitis. This report described the CT diagnosis of broncholithiasis, which has been rarely reported in a cat.