Tomography In Dogs Research Articles

Rectus sheath block results in greater cranial-caudal spread whereas transversus abdominis plane block results in greater lateral spread as assessed by computed tomography in dogs.

To evaluate the in vivo spread of iodinated contrast following injections in the transversus abdominis plane (TAP) and rectus sheath in anesthetized dogs via computed tomography. Secondarily, the time of performing each block was compared. 6 adult, purpose-bred Beagles. In a prospective crossover study, dogs were administered injections either in the rectus sheath or transversus abdominis fascial plane in the same manner as a rectus sheath block (RSB) or TAP block using dilute iodinated contrast. Computed tomography scans were performed immediately following injection (time [T]-0) and at 3, 9, 18, and 30 minutes postinjection. Data regarding the spread in the cranial-caudal and lateral directions and time to perform the injections were compared between the 2 techniques using paired or 2-sample t tests. There was significantly greater spread in the cranial-caudal direction in the RSB group (62.9 ± 6.4 mm vs 54.8 ± 6.8 mm at T30; P = .009), whereas spread in the lateral direction was greater in the TAP group (37.3 ± 3.0 mm vs 48.6 ± 6.1 mm at T30; P < .0001). The RSB injection was performed in a more time-efficient manner than TAP injection (48.2 ± 3.2 seconds vs 82.3 ± 8.7 seconds; P = .03). In living subjects, RSB injections resulted in greater cranial-caudal spread while TAP injections resulted in greater lateral spread. Rectus sheath block injections were performed in a more time efficient manner compared to a single point TAP injection in anesthetized dogs. The RSB was performed in a more time-efficient manner and would likely result in greater coverage of the ventral midline. The TAP block would likely result in more significant regional anesthetic coverage of the lateral abdominal wall. Further studies are required to determine the degree of the clinical significance of these results.

Correlation between microvascular density and perfusion parameters derived from dynamic contrast-enhanced computed tomography in dogs with tumors of the head

BackgroundNon-resectable tumors of the head can represent a therapeutic challenge in dogs and prognostic indicators and markers of response to treatment are needed. Tumor microenvironment, in particular microvascular density (MVD), affects response to treatment and prognosis.MethodsPerfusion parameters obtained from dynamic contrast-enhanced computed tomography (DCECT) have been correlated to MVD and outcome in humans. Twenty-five dogs comprising 16 epithelial tumors and 9 mesenchymal tumors of the head were prospectively recruited and underwent DCECT. Microvascular density (anti-Factor VIII) was assessed using a trained object classifier in stroma and tumor tissue.ResultsMesenchymal tumors had significantly higher percentage area of blood vessels in tumor tissue than epithelial tumors (P = .04). There was no significant association between perfusion parameters and MVD measurements.ConclusionsThese findings suggest that mesenchymal tumors have a higher MVD than epithelial tumors, and that perfusion parameters derived from DCECT might not be well correlated with MVD in dogs with tumors of the head.

Evaluation of changes in lacrimal canaliculi width depending on temperature and viscosity of eye drops using spectral-domain optical coherence tomography in dogs.

To evaluate the changes in the width of the lower lacrimal canaliculi (LC) upon instillation of artificial tears (AT) at different temperatures and viscosities using spectral-domain optical coherence tomography (SD-OCT). Eight eyes of four client-owned adult dogs. Imaging of lower LC was performed under general anesthesia. AT at temperatures of 2°C, 20°C, and 38°C, and a high-viscosity tear gel of 20°C, were topically instilled in 100 μL volumes. SD-OCT tracked LC width changes following each instillation. The average baseline width of the LC was 96.38 ± 30.18 μm. The 2°C AT expanded LC width to 183.50 ± 44.11 μm, returning to baseline in 5.00 ± 1.31 min. The 20°C AT resulted in a width of 155.25 ± 35.79 μm, with a 3.88 ± 1.25 min return. The 38°C AT expanded LC width to 131.75 ± 29.49 μm, with a 2.25 ± 0.89 min return. The high-viscosity tear gel expanded LC width to 208.57 ± 56.31 μm, with remained expanded for 10 or more minutes. In temperature comparisons, the 2°C and 20°C AT significantly expanded the LC width more and had longer return times than the 38°C AT (p < .05). Viscosity comparisons showed higher viscosity eye drops significantly expanded LC width more than lower viscosity eye drops (p < .05). This study found that lower temperature and higher viscosity of eye drops had tendency to result in a wider expansion of the LC width. Additionally, the return time to baseline for LC width tended to be longer with eye drops of lower temperature and higher viscosity. This finding could be helpful in advancing future research on tear dynamics.

Improved detection of air-filled lesions using computed tomography in dogs with recurrent spontaneous pneumothorax through reduction of pulmonary atelectasis via positive pressure ventilation.

Spontaneous pneumothorax in dogs is predominantly caused by the rupture of air-filled lesions, such as bullae or blebs. The efficacy of Computed Tomography (CT) in detecting these lesions has been deemed limited due to its reportedly low sensitivity. This retrospective, cross-sectional study investigates the utility of CT in eight dogs diagnosed with recurrent pneumothorax, all of which had surgical confirmation of the cause of the pneumothorax. Thoracic radiographs were obtained before and the day following the CT studies. Initially, a CT study was conducted without positive pressure ventilation (pre-PPV CT). Subsequent CT studies were performed post-evacuation of pneumothorax and with positive pressure ventilation of 15 cmH2O until lung atelectasis was resolved (post-PPV CT). The pre-PPV CT and post-PPV CT images were anonymized and reviewed by two board-certified radiologists. The presence and morphology of air-filled lesions were evaluated on all images. Surgical findings were recorded and compared to the CT findings. Air-filled lesions were detected in 5 out of 8 dogs in the pre-PPV CT studies and in all 8 dogs in the post-PPV CT studies. The CT findings of air-filled lesions were consistent with surgical findings. None of the dogs showed increased severity of pneumothorax in radiographs taken the day following the CT studies. The study concludes that the resolution of lung atelectasis by evacuation of pneumothorax and positive pressure ventilation during CT studies is feasible and enhances the detection of air-filled lesions in dogs with recurrent spontaneous pneumothorax. This could potentially aid in improving surgical planning.

Virtual non-contrast images of detector-based spectral computed tomography in dogs: a promising alternative to true non-contrast images in veterinary medicine.

In veterinary medicine, abdominal computer tomographic (CT) examinations regularly require a minimum of two scans, with a native scan (true unenhanced, TUE) as a reference for the subsequent contrast-enhanced CT scan (CECT). Spectral detector CT (SDCT) offers the possibility to calculate virtual non-contrast (VNC) images from the post-contrast scan, but this has not yet been investigated in veterinary medicine. The purpose of this study was to assess the reliability of VNC images for abdominal organs in 44 dogs without abdominal pathologies by evaluating their quantitative and qualitative parameters compared to TUE images. We hypothesized that the subtraction of iodine is sufficient in the VNC series compared to the TUE series and that the image quality of the SDCT series is superior to conventional CT images. Corresponding attenuation values in the VNC and TUE series regarding the regions of interest (ROI) in different parenchymal organs and major vessels of the abdominal cavity were assessed by means of a two one-sided t-test (TOST) and Bland-Altman plots. Additionally, the signal-to-noise ratio (SNR) was calculated for each ROI in the different series. In the second step, two board-certified veterinary radiologists made a qualitative assessment of VNC images vs. TUE images in consensus by rating the iodine subtraction, image noise, and image quality of VNC images based on a specific 5-point Likert scale. The difference in corresponding Hounsfield units (HUs) between TUE and VNC images was less than 10 HU in 78.67% of all ROIs. Regarding the limit of less than 10 HU, in the performed TOST, significant p-values of < 0.05 were reached for the liver, spleen, pancreas, and musculature, implying equivalence of both modalities. The quality of spectral base image (SBI) data was rated equivalent to calculated conventional images in the subjective assessment by reaching an average Likert scale score of 3.2 points. VNC images calculated from SDCT data prove a valid alternative to conventional TUE images in the abdominal organs of canine patients without abdominal pathology. VNC offers the possibility to reduce time under general anesthesia and minimize radiation exposure. Future studies are needed to prove the application of this method in clinically diseased patients.

Thoracic computed tomography in dogs with neoplasia

Computer tomography has been described for the detection and characterization of different thoracic neoplastic diseases in dogs, both primary and metastatic. Its use and availability in veterinary medicine are rapidly increasing in the clinical setting, particularly in referral practices. Due to the cross-sectional nature of this modality, CT is particularly useful in the assessment of complex anatomical regions, such as the thoracic cavity. In this review, the most common applications of thoracic CT for the diagnosis and staging of different neoplastic processes in dogs are highlighted.

Retrospective evaluation of the diagnostic utility of computed tomography in dogs with nontraumatic hemoperitoneum: 26 cases (2015-2020).

To describe the appearance of lesions noted on abdominal computed tomography (CT) in dogs with spontaneous hemoperitoneum and determine the utility in using CT to differentiate benign from malignant lesions. Retrospective case series. Single-center, university veterinary teaching emergency service. Twenty-six dogs presented between 2015 and 2020 with spontaneous hemoperitoneum confirmed via abdominocentesis with pre- and postcontrast abdominal CT performed prior to surgery or euthanasia. None. On histopathological diagnosis, 20 of 26 lesions were found to be malignant, and 6 of 26 were benign. Two radiologists reviewed the CTs. Radiologist 1 correctly identified 5 of 6 (83.3%) benign cases and 18 of 20 (90%) malignant cases. Radiologist 2 correctly identified 2 of 6 (33.3%) benign lesions and 18 of 20 (90%) malignant cases. Of the 10 imaging descriptors evaluated, none were significantly associated with the histological diagnosis. Results from the current study suggest that abdominal CT imaging of spontaneous hemoperitoneum cases is not a reliable indicator of malignancy versus benignancy. As such, prognosis should not be defined using this modality alone prior to emergency surgery and instead should be concluded based on the clinical course of the patient and histopathological findings of the resected tissues after surgery.

Assessment of Abdominal Organs Movement by Respiration Using Computed Tomography in Dogs: A Pitfall for Radiation Therapy

Assessment of Abdominal Organs Movement by Respiration Using Computed Tomography in Dogs: A Pitfall for Radiation Therapy

Dynamic contrast-enhanced computed tomography in dogs with nasal tumors.

Treatment of nasal tumors in dogs is associated with high morbidity and reliable prognostic factors are lacking. Dynamic contrast-enhanced computed tomography (DCECT) can be used to assess tumor perfusion. To assess perfusion parameters of nasal tumors (correlating with tumor type) before and during radiotherapy (RT) and find potential correlation with survival. Twenty-four client-owned dogs with nasal tumors, including 16 epithelial tumors and 8 sarcomas. Prospective cross-sectional study. All dogs had baseline DCECT to assess fractional vascular volume (BV), blood flow (BF), and transit time (TT). Thirteen dogs had repeat DCECT after 12 Gy of megavoltage RT. Survival times were calculated. Median BV was 17.83 mL/100 g (range, 3.63-66.02), median BF was 122.63 mL/100 g/minute (range, 23.65-279.99), and median TT was 8.91 seconds (range, 4.57-14.23). Sarcomas had a significantly lower BF than adenocarcinomas (P = .002), carcinomas (P = .01), and other carcinomas (P = .001), and significantly lower BV than adenocarcinomas (P = .03) and other carcinomas (P = .004). Significant associations were found between epithelial tumors and sarcoma for change in tumor volume (P = .01), width (P = .004), and length (P = .02) in that epithelial tumors decreased in volume whereas sarcomas increased in volume. Perfusion parameters were not correlated with survival. Nasal sarcomas have lower BV and BF than nasal carcinomas, and sarcomas have a lower size reduction than carcinomas early on during RT. Baseline results and changes in perfusion parameters may not be correlated with survival.

Clinical utility of a new protocol of cardiac computed tomography in dogs.

The characteristics of non-electrocardiography- and electrocardiography-gated multidetector computed tomography have not been extensively studied in veterinary clinics but it can be useful for cardiac imaging. This study aimed to ascertain the differences between non-electrocardiography and electrocardiography gating methods and to establish their clinical utility based on patient history. Six client-owned dogs (two with patent ductus arteriosus, two with heart base tumour, one with pericardial mesothelioma, and one with normal health) were included in this study. All the dogs were examined using a non-electrocardiography-gated scan, followed by a retrospective electrocardiography-gated scan. Images were reviewed to determine the optimal scan timing and R-R interval in non-electrocardiography- and electrocardiography-gated images, respectively, for detailed coronary artery imaging, diagnostic quality of the best coronary artery visualisation in non-electrocardiography- and electrocardiography-gated images through visual assessment of the main coronary artery branches, and branching patterns of the left coronary artery. Further, we compared the size and margin demarcation of the heart or pericardial lesions in non-electrocardiography- and electrocardiography-gated images obtained from patients with heart or pericardial tumours. The optimal scan timing and R-R interval were the second-scan timing and end-diastole (70%-90%), respectively. Second-scan non-electrocardiography-gated images allowed coronary artery evaluation, indicating high-grade quality in visual assessment, except for the septal branch. Electrocardiography-gated images, but not non-ECG-gated images, clearly revealed pericardial nodules in two dogs. Our findings suggest the respective clinical utilities of non-electrocardiography- or electrocardiography-gated imaging using high-slice cardiac computed tomography based on patient history.

Outer retinal thickness and visibility of the choriocapillaris in four distinct retinal regions imaged with spectral domain optical coherence tomography in dogs and cats.

PurposeTo evaluate the outer retinal band thickness and choriocapillaris (CC) visibility in four distinct retinal regions in dogs and cats imaged with spectral domain optical coherence tomography (SD‐OCT). To attempt delineation of a fovea‐like region in canine and feline SD‐OCT scans, aided by the identification of outer retinal thickness differences between retinal regions.MethodsSpectralis® HRA + OCT SD‐OCT scans from healthy, anesthetized dogs (n = 10) and cats (n = 12) were analyzed. Scanlines on which the CC was identifiable were counted and CC visibility was scored. Outer nuclear layer (ONL) thickness and the distances from external limiting membrane (ELM) to retinal pigment epithelium/Bruch's membrane complex (RPE/BM) and ELM to CC were measured in the area centralis (AC), a visually identified fovea‐like region, and in regions superior and inferior to the optic nerve head (ONH). Measurements were analyzed using a multilevel regression.ResultsThe CC was visible in over 90% of scanlines from dogs and cats. The ONL was consistently thinnest in the fovea‐like region. The outer retina (ELM‐RPE and ELM‐CC) was thickest within the AC compared with superior and inferior to the ONH in dogs and cats (p < .001 for all comparisons).ConclusionsThe CC appears a valid, albeit less than ideal outer retinal boundary marker in tapetal species. The AC can be objectively differentiated from the surrounding retina on SD‐OCT images of dogs and cats; a fovea‐like region was identified in dogs and its presence was suggested in cats. These findings allow targeted imaging and image evaluation of these regions of retinal specialization.

Assessment of Regional Ventilation During Recruitment Maneuver by Electrical Impedance Tomography in Dogs.

BackgroundDuring protective mechanical ventilation, electrical impedance tomography (EIT) is used to monitor alveolar recruitment maneuvers as well as the distribution of regional ventilation. This technique can infer atelectasis and lung overdistention during mechanical ventilation in anesthetized patients or in the ICU. Changes in lung tissue stretching are evaluated by monitoring the electrical impedance of lung tissue with each respiratory cycle.ObjectiveThis study aimed to evaluate the distribution of regional ventilation during recruitment maneuvers based on the variables obtained in pulmonary electrical impedance tomography during protective mechanical ventilation, focusing on better lung recruitment associated with less or no overdistention.MethodsProspective clinical study using seven adult client–owned healthy dogs, weighing 25 ± 6 kg, undergoing elective ovariohysterectomy or orchiectomy. The animals were anesthetized and ventilated in volume-controlled mode (7 ml.kg−1) with stepwise PEEP increases from 0 to 20 cmH2O in steps of 5 cmH2O every 5 min and then a stepwise decrease. EIT, respiratory mechanics, oxygenation, and hemodynamic variables were recorded for each PEEP step.ResultsThe results show that the regional compliance of the dependent lung significantly increased in the PEEP 10 cmH2O decrease step when compared with baseline (p < 0.027), and for the nondependent lung, there was a decrease in compliance at PEEP 20 cmH2O (p = 0.039) compared with baseline. A higher level of PEEP was associated with a significant increase in silent space of the nondependent regions from the PEEP 10 cmH2O increase step (p = 0.048) until the PEEP 15 cmH2O (0.019) decrease step with the highest values at PEEP 20 cmH20 (p = 0.016), returning to baseline values thereafter. Silent space of the dependent regions did not show any significant changes. Drive pressure decreased significantly in the PEEP 10 and 5 cmH2O decrease steps (p = 0.032) accompanied by increased respiratory static compliance in the same PEEP step (p = 0.035 and 0.018, respectively).ConclusionsThe regional ventilation distribution assessed by EIT showed that the best PEEP value for recruitment maintenance, capable of decreasing areas of pulmonary atelectasis in dependent regions promoting less overinflation in nondependent areas, was from 10 to 5 cmH2O decreased steps.

Evaluation of caudal vena cava size using computed tomography in dogs under general anesthesia.

This study investigated the association between caudal vena cava (CVC) size and circulatory dynamics in dogs using computed tomography (CT) under general anesthesia. The subjects were 104 dogs who had undergone CT under general anesthesia in the past. The ratio of short diameter of the CVC to aortic diameter (CVCS/Ao) and the ratio of long to short diameter of the CVC (CVCL/CVCS) in the thorax and abdomen, respectively, were calculated using factors such as mean blood pressure (MBP), shock index (SI), anemia, hypoproteinemia, presence of intra-abdominal mass, and cardiac disease. There was a significant but negligible negative correlation between CVCS/Ao and MBP. In contrast, no significant correlation was found between CVC size and SI. The low MBP group had significantly higher CVCS/Ao of the thorax than the normal MBP group. The group with intra-abdominal mass had significantly lower CVCS/Ao of the abdomen than the group without intra-abdominal mass. The group with cardiac disease had significantly lower CVCL/CVCS of the thorax than the group without cardiac disease. In multiple regression analysis, low MBP, cardiac disease, intra-abdominal mass, and anemia were significant factors for CVCS/Ao of the thorax, CVCL/CVCS of the thorax, CVCS/Ao of the abdomen, and CVCL/CVCS of the abdomen, respectively. In conclusion, CVC size assessment using CT in dogs under general anesthesia is influenced by various factors.

Biodistribution and image characteristics of 124I‐positron emission tomography in dogs with neuroendocrine neoplasia

Radioactive iodine is frequently used for staging of human thyroid carcinomas. Iodine-124 scans performed using position emission tomography (PET) allow for more precise dosimetry of therapeutic radioiodine. The distribution of I-124 has not previously been described in veterinary medicine. The purpose of this prospective, exporatory, descriptive study is to evaluate the whole-body distribution of I-124 in dogs with suspected thyroid carcinoma. Ten dogs with either a cytologic diagnosis of a neuroendocrine neoplasm or biochemical hyperthyroidism were enrolled in a prospective clinical study. Whole-body I-124 PET/CT scans were performed and were evaluated for physiologic and pathologic uptake of I-124. The maximum and mean standardized uptake values (SUVmean) were recorded for several normal and abnormal tissues. Varying degrees of uptake were found in thyroid tumors (SUVmean=66.37), ectopic thyroid masses (21.44), presumed metastatic lesions in lymph nodes (32.14), and the pulmonary parenchyma (4.50). In most dogs, physiologic uptake above background, measured in maximum SUV, was identified in parotid and mandibular salivary glands (14.00 and 1.57) the urinary tract (1.83), the gastrointestinal tract (19.90 stomach, 6.15 colon), the liver (1.41), and the heart (1.88). Occasionally, uptake was identified in the nasolacrimal duct (3.42), salivary duct (2.73), gallbladder (2.68), and anal gland (2.22). Physiologic uptake was also identified in normal thyroid glands and ectopic thyroid tissue. This study provides a baseline of pathologic and physiologic uptake of I-124 in dogs with thyroid carcinoma, to guide interpretation of future studies.

The diagnostic value of intravenous contrast computed tomography in addition to plain computed tomography in dogs with head trauma

BackgroundThe aim of this study is to evaluate additional findings which can be detected by post-contrast computed tomography (CCT) in relation to plain CT (PCT) findings in patients presented with head trauma. Medical records of canine patients with the history of head trauma from three institutions were reviewed. PCT- and CCT-anonymized images were evaluated by a veterinary radiologist separately. From the categorized findings the following conclusions were drawn as: abnormalities were identified on (A) PCT but missed on CCT, (B) CCT but missed on PCT, (C) both PCT and CCT.ResultsThirty-two patients were included. The results showed that findings identified on CCT or PCT (category A and B) but missed on the other series were limited to mild soft tissue and sinus changes. Overall, 61 different fracture areas, 6 injuries of the temporomandibular joint (TMJ), 4 orbital injuries, 14 nasal cavities with soft tissue density filling, 13 areas of emphysema, 4 symphysis separations, 12 intracranial hemorrhages, 6 cerebral edema, 5 cerebral midline shifts, 3 intracranial aeroceles, 3 brain herniations and 6 intraparenchymal foreign bodies (defined as an abnormal structure located within the brain: e.g. bony fragments, bullet, teeth,..) were identified on both PCT and CCT separately (category C). Severity grading was different in 50% (3/6) of the reported cerebral edema using PCT and CCT images.ConclusionThe results showed that PCT is valuable to identify the presence of intracranial traumatic injuries and CCT is not always essential to evaluate vital traumatic changes.

Diagnosis of pulmonary contusions with point-of-care lung ultrasonography and thoracic radiography compared to thoracic computed tomography in dogs with motor vehicle trauma: 29 cases (2017-2018).

To determine the accuracy of lung ultrasound (LUS) using the Veterinary Bedside Lung Ultrasound Examination (VetBLUE) protocol and 3-view thoracic radiographs (TXR) compared to thoracic computed tomography (TCT) for diagnosing the presence and quantification of pulmonary contusions (PC). Prospective cohort study conducted from February 2017 to June 2018. Private emergency and referral center. Thirty-two dogs having sustained motor vehicle trauma were consecutively enrolled. Three dogs were excluded from statistical analysis. All dogs survived to hospital discharge. Within 24hours of sustaining trauma, dogs had LUS, TXR, and TCT performed. Using the VetBLUE protocol, LUS PC were scored according to the presence and number of B-lines and C-lines, indicating extravascular lung water. Thoracic radiographs and TCT were scored for PC in a similar topographical pattern to the VetBLUE protocol. Lung ultrasound and TXR were compared to "gold standard" TCT for the presence and quantification of PC. On TCT, 21 of 29 (72.4%) dogs were positive and 8 of 29 (27.6%) dogs were negative for PC. When LUS was compared to TCT, 19 of 21 dogs were positive for PC (90.5% sensitivity) and 7 of 8 dogs were negative (87.5% specificity) for PC. LUS PC score correlated strongly with TCT PC score (R=0.8, P<0.001). When TXR was compared to TCT, 14 of 21 dogs were positive for PC (66.7% sensitivity) and 7 of 8 dogs were negative (87.5% specificity) for PC. TXR PC score correlated strongly with TCT PC score (R=0.74, P<0.001). In this population of dogs with motor vehicle trauma, LUS had high sensitivity for diagnosis of PC when compared to "gold standard" TCT. LUS provides reliable diagnosis of PC after trauma. More patients with PC were identified with LUS than with TXR, and additional studies are warranted to determine whether this increased sensitivity is statistically significant.

Evaluation of Azygos Vein to Aorta Ratio using Multi-Detector Computed Tomography in Dogs

The purpose of this study is to evaluate the azygos vein to aorta diameter ratio (AV/AO ratio) in healthy dogs and dogs with diseases that may cause azygos vein dilation. The normal groups included eleven healthy beagle dogs and eleven small breed dogs. The abnormal group included 43 dogs that had diseases with high right atrial pressure (RA group), obstruction of cranial or caudal vena cava (CVC group) and porto-azygos shunt group (PSS group). The diameter of AV and AO were measured at three sites on thoracic CT images; the level of the cranial endplate of 12th thoracic vertebra (TV level), the tracheal bifurcation (TB level) and the insertion to the cranial vena cava (CrVC level). The AV/AO ratio at the CrVC level had significantly higher values than those at the TV and TB levels in the normal groups. The AV/AO ratios of TV and TB levels in the CVC group and the values at all measurement sites of the PSS group were significantly higher than the normal groups. AV/AO ratio will be a useful factor for the evaluation of various clinical conditions that change the AV diameter with respect independent to the body weight in dogs.

Prognostic value of fluorine18 flourodeoxyglucose positron emission tomography/computed tomography in dogs with appendicular osteosarcoma.

BackgroundFactors indicative of a negative prognosis for appendicular osteosarcoma (OSA) in dogs are visible metastatic disease, location, and size of lesion. In human medicine maximum standard uptake value (SUVmax), as measured on a fluorine18 flourodeoxyglucose positron emission tomography/computed tomography (18F‐FDG PET/CT), is prognostic for survival for several tumor types.ObjectiveDetermine if SUVmax is associated with progression‐free interval (PFI) and determination of survival in dogs with appendicular OSA.AnimalsSixty‐two dogs with untreated appendicular OSA that had been staged with 18F‐FDG PET/CT.MethodsRetrospective analysis of the 18F‐FDG PET/CT was performed. Dogs were excluded from the study if they did not receive definitive intent treatment for their primary OSA and adjuvant chemotherapy with carboplatin, or had visible metastatic disease on initial imaging. A region of interest (ROI) was created around the primary tumor to measure SUVmax. Univariable and multivariable Cox proportional hazards analysis was performed to evaluate for associations between variables including SUVmax and outcome of PFI and overall survival (OS).ResultsMaximum standard uptake value of the primary tumor was significantly associated with the OS (P = .04) with adjustment for treatment type and monocyte count. The overall median survival time (OST) was 284 days (range, 39‐1293 days) with the OST of dogs having an SUVmax of ≥7.4 of 254 days (range, 98‐428 days) and dogs with an SUVmax of <7.4 of 680 days (range, 108‐811 days, P = .01).Conclusions and Clinical ImportanceMaximum standard uptake value as measured via 18F‐FDG PET/CT is significantly associated with survival in dogs with appendicular OSA with a high SUVmax being an indicator of a negative prognosis.

Validation of ultrasonographic muscle thickness measurements as compared to the gold standard of computed tomography in dogs.

ObjectiveThe objective was to quantitatively evaluate the validity of ultrasonographic (US) muscle measurements as compared to the gold standard of computed tomography (CT) in the canine.DesignThis was a prospective study.PopulationTwenty-five, client-owned dogs scheduled for CT as part of a diagnostic work-up for the management of their primary disease process were included.Materials and MethodsSpecific appendicular (cubital flexors and extensors, coxofemoral flexors and extensors) and axial (temporalis, supraspinatus, infraspinatus, lumbar epaxials) muscle groups were selected for quantitative measure based on CT planning and patient position. Prior to CT scan, the skin over the muscle sites was shaved and marked with a permanent marker. Patient body position was determined based on the patient’s CT plan; positioning was consistent between CT and US imaging. To ensure identical imaging position for both CT and US measurements, radio-opaque fiducial markers were placed directly over the skin marks once the dog was positioned. Quantitative measurements (cm) for both lean muscle mass (LMM) and subcutaneous adipose (SQA) were recorded. Statistical comparisons between CT and US values were done separately for each site and type.ResultsMuscle groups and associated SQA measured by US and CT were not statistically different based on an adjusted p-value using Bonferroni’s correction (p < 0.0031). In addition, all LMM and SQA sites had good reliability and agreement (Cronbach’s α = 0.8 − 1.0) between the two metrics, excluding the coxofemoral extensor muscle group (Cronbach’s α = 0.73232). Linear regression analysis of muscle measures indicated close agreement (slope range 0.93–1.09) and minimal bias of variation (intercept range 0.05–0.11) between CT versus US modalities, with the exception of the coxofemoral extensor muscle. Similarly, SQA CT and US measures indicated close agreement with the slope range of 0.88–1.02 and minimal bias of variation with an intercept range of 0.021–0.098, excluding the cubital flexor and extensor groups. Additionally, the R2 values for these remaining LMM and SQA sites are reported as >0.897 for LLM and >0.8289 for SQA.ConclusionsUltrasound imaging of selected appendicular and axial muscle groups in dogs can provide comparable assessment of muscle thickness to the current gold standard, CT. In consideration of both statistical reliability to CT and cage-side accessibility, the temporalis, supraspinatus, infraspinatus, and lumbar epaxial LMM sites are considered the most useful targets for US LMM assessment in the canine. Our findings support the potential utility of US as a clinical tool in veterinary medicine to assess LMM status in patients. Additional studies are indicated to develop standardized protocols of its use in a cage-side setting and to elucidate the benefit of this modality, in conjunction with nutritional interventions, to manage body LLM stores in compromised patients.

Triple-phase helical computed tomography in dogs with solid splenic masses.

We investigated the utility of triple-phase helical computed tomography (CT) in differentiating between benign and malignant splenic masses in dogs. Forty-two dogs with primary splenic masses underwent triple-phase helical CT scanning (before administration of contrast, and in the arterial phase, portal venous phase, and delayed phase) prior to splenectomy. Tissue specimens were sent for pathological diagnosis; these included hematomas (n=14), nodular hyperplasias (n=12), hemangiosarcomas (n=11), and undifferentiated sarcomas (n=5). The CT findings were compared with the histological findings. Nodular hyperplasia significantly displayed a homogeneous normal enhancement pattern in all phases. Hemangiosarcoma displayed 2 significant contrast-enhancement patterns, including a homogeneous pattern of poor enhancement in all phases, and a heterogeneous remarkable enhancement pattern in the arterial and portal venous phases. Hematoma and undifferentiated sarcoma displayed a heterogeneous normal enhancement pattern in all phases. The contrast-enhanced volumetric ratios of hematoma tended to be greater than those of undifferentiated sarcoma. Our study demonstrated that the characteristic findings on triple-phase helical CT could be useful for the preoperative differentiation of hematoma, nodular hyperplasia, hemangiosarcoma, and undifferentiated sarcoma in dogs. Triple-phase helical CT may be a useful diagnostic tool in dogs with splenic masses.