Objective—To determine the incidence and type of alterations in heart rate (HR), peak systolic blood pressure (PSBP), and serum biochemical variables (total bilirubin, BUN, and creatinine concentrations) associated with IV administration of ionic-iodinated contrast (IIC), nonionic-iodinated contrast (NIC), and gadolinium dimeglumine (GD) contrast media in anesthetized dogs.
Procedures—HR and PSBP were recorded at 5-minute intervals for 20 minutes for untreated control dogs and dogs that received IIC, NIC, or GD contrast medium. The development of an HR of < 60 beats/min or > 130 beats/min that included a ≥ 20% change from baseline was considered a response. The development of PSBP of < 90 mm Hg or > 160 mm Hg that included a ≥ 20% change from baseline was considered a response. Pre- and postcontrast serum biochemical values were recorded.
Results—Of dogs receiving IIC medium, 3% (3/91) had a response in HR and 4% (4/91) had a response in PSBP at ≥ 1 time points. None of the dogs receiving NIC medium had a response in HR; 1 of 16 had a response in PSBP. Of dogs receiving GD contrast medium, 1% (1/92) had a response in HR and 4% (4/92) had a response in PSBP. Of control dogs, 2% (2/81) had a response in HR and 4% (3/81) had a response in PSBP. No serum biochemical alterations were observed.
Conclusions and Clinical Relevance—IV administration of contrast media in anesthetized dogs caused moderate bradycardia, tachycardia, hypotension, or hypertension.
Objective—To determine the incidence and type of alterations in heart rate (HR), peak systolic blood pressure (PSBP), and serum biochemical variables (serum total bilirubin, BUN, and creatinine concentrations) associated with IV administration of ionic-iodinated contrast (IIC), nonionic-iodinated contrast (NIC), and gadolinium (GD) contrast media in anesthetized cats.
Procedures—HR and PSBP were recorded at 5-minute intervals for 20 minutes for untreated control cats and cats that received IIC, NIC, or GD contrast medium. The development of HR < 100 beats/min or > 200 beats/min that included a ≥ 20% change from baseline was considered a response. The development of PSBP of < 90 mm Hg or > 170 mm Hg that included a ≥ 20% change from baseline was considered a response. Pre- and postcontrast serum biochemical values were recorded.
Results—Of cats receiving IIC medium, 2% (1/60) had a response in HR at ≥ 1 time point. Of cats receiving IIC medium, 7% (4/60) had a response in PSBP. None of the cats receiving NIC medium had a response in HR; 2 of 12 had a response in PSBP. Of cats receiving GD contrast medium, 6% (5/83) had a response in HR and 8% (7/83) had a response in PSBP. None of the control cats had a response in HR or PSBP. No serum biochemical alterations were observed.
Conclusions and Clinical Relevance—IV administration of iodine and GD contrast media in anesthetized cats was associated with changes in HR and PSBP.
Case Description—Acute severe systemic reactions developed during IV administration of an ionic iodinated contrast agent (iothalamate meglumine) in 2 dogs undergoing contrast-enhanced computed tomography.
Clinical Findings—Both dogs developed marked changes in heart rate and systolic arterial blood pressure during or immediately after IV administration of the contrast agent. The first dog became profoundly hypertensive and bradycardic with poor oxygenation, apparent bronchospasm, and prolonged diarrhea. The second dog became hypotensive and tachycardic with erythema on the ventral aspect of the abdomen and pelvic limbs, periocular edema, and diarrhea.
Treatment and Outcome—Both dogs were treated for shock by means of IV fluid administration, and anesthesia was discontinued. The first dog was placed on a ventilator to improve oxygenation but was hypertensive and unresponsive for 6.5 hours following contrast agent administration. Bloody diarrhea persisted once consciousness was regained. The dog was discharged 3 days after contrast agent administration, and diarrhea resolved 15 days later. The second dog responded to phenylephrine administration, but urine output appeared low immediately following recovery from anesthesia. Urine output was normal the following day, and the dog was released 36 hours after contrast administration with no residual adverse effects.
Clinical Relevance—Findings highlighted the potential risk for severe reactions associated with IV administration of ionic iodinated contrast agents in dogs. Both hypertensive and hypotensive responses were seen. Supportive care for systemic manifestations was effective in these 2 dogs, and extended hospitalization was not necessary.
Objective—To compare the use of radiography and fluoroscopy for detection and grading of tracheal collapse in dogs.
Design—Retrospective case series.
Animals—62 dogs with tracheal collapse.
Procedures—For each dog, tracheal collapse was confirmed fluoroscopically and lateral cervical and thoracic radiographic views were reviewed. A board-certified radiologist (who was unaware of the dogs' clinical history) evaluated the cervical, thoracic inlet, thoracic, carinal, and main stem bronchial regions in all fluoroscopic videos and radiographic images for evidence of collapse. Cervical, thoracic inlet, thoracic, and carinal regions in both radio-graphic and fluoroscopic studies were graded for collapse (0%, 25%, 50%, 75%, or 100% decrease in diameter).
Results—Lateral cervical and thoracic radiographic images were available for 54 dogs, and inspiratory and expiratory lateral cervical and thoracic radiographic images were available for 8 dogs. For detection of tracheal collapse, assessment of radiographic views was sensitive and had the best negative predictive value in the cervical and thoracic inlet regions. Assessment of radiographic views was most specific and had the best positive predictive value in the thoracic inlet, thoracic, carina, and main stem bronchial regions. Radiography underestimated the degree of collapse in all areas. Review of inspiratory and expiratory views improved the accuracy of radiography for tracheal collapse diagnosis only slightly.
Conclusions and Clinical Relevance—Compared with fluoroscopy, radiography underestimated the frequency and degree of tracheal collapse. However, radiography appears to be useful for screening dogs with potential tracheal collapse.
Case Description—An 11-year-old castrated male Tibetan Mastiff was evaluated because of a visibly enlarged blood vessel and progressively worsening swelling of the right hind limb.
Clinical Findings—On physical examination, the right hind limb was markedly larger than the left hind limb and the dog was minimally weight bearing on the affected limb. A bruit was auscultated over the affected region. Ultrasonography of the tarsal region of the right hind limb revealed an artery with turbulent flow that communicated with venous drainage. A CT scan confirmed the presence of an arteriovenous malformation (AVM).
Treatment and Outcome—Embolization of the AVM with a liquid embolic agent (ethylene-vinyl alcohol copolymer dissolved in dimethyl sulfoxide) was elected. An arteriogram was performed prior to treatment and delineated the vessels that were targeted for embolization. The embolic agent was infused into the AVM, and a postinjection arteriogram confirmed complete occlusion of the AVM nidus and normal arterial flow to the paw with subsequent normal venous drainage. The circumference of the abnormal paw was 51 cm before the procedure and 22.9 cm at 4 weeks after the procedure. Additionally, the gait of the dog dramatically improved. No complications associated with the procedure developed.
Clinical Relevance—Peripheral AVMs in dogs are uncommon, and described treatment options are limited and generally associated with serious morbidity. A liquid embolic agent, ethylene-vinyl alcohol copolymer dissolved in dimethyl sulfoxide, was successfully administered in this case, and no morbidity was observed secondary to the procedure. Clinical success was characterized by substantial improvement in limb swelling and marked improvement in the gait of the dog.
Objective—To compare imaging findings in dogs with pituitary-dependent hyperadrenocorticism (PDH) that did or did not have neurologic abnormalities.
Design—Retrospective case series.
Animals—157 dogs with PDH that did (n = 73) or did not (84) have neurologic abnormalities.
Procedures—Medical records were reviewed for the presence and nature of clinical signs of CNS disease, and computed tomographic and magnetic resonance images were reviewed for evidence of a pituitary tumor.
Results—60 of the 84 (71%) dogs without neurologic abnormalities and 48 of the 73 (66%) dogs with neurologic abnormalities had a detectable pituitary tumor. However, 17 of the 84 (20%) dogs without neurologic abnormalities had a pituitary macrotumor (ie, a tumor ≥ 10 mm in height), and 41 of the 73 (56%) dogs with neurologic abnormalities did not have a detectable pituitary tumor or had a pituitary microtumor. Vague signs of CNS dysfunction (ie, lethargy, inappetence, and mental dullness) were more specific for detection of pituitary macrotumors than were CNS-specific signs (ie, seizure or blindness).
Conclusions and Clinical Relevance—Results suggested that there was no apparent relationship between a pituitary tumor and development of neurologic abnormalities in dogs with PDH. In addition, neurologic abnormalities in dogs with pituitary macrotumors were often vague (ie, lethargy, inappetence, and mental dullness).
Objective—To determine the degree of fluctuation in tracheal dimensions between forced inspiration and passive expiration in healthy dogs of various sizes.
Animals—10 client-owned dogs with no evidence of respiratory disease or tracheal collapse.
Procedures—Anesthetized dogs underwent a computed tomographic examination during forced inspiration and induced but passive expiration to assess tracheal dimensions. Tracheal height, width, and cross-sectional area were measured at inspiration and expiration, and percentage change in dimension was calculated for each variable.
Results—Measurements were acquired in 10 dogs that ranged in body weight from 3.5 to 47.8 kg. Tracheal cross-sectional area at inspiration and expiration was associated with body weight at all 3 tracheal regions. The percentage change in tracheal height and cross-sectional area was associated with body weight in the cervical but not the thoracic-inlet or thoracic regions. The tracheal cross-sectional area changed by as much as 24.2% (mean, 5.5%), 20.0% (mean, 6.0%), and 18.6% (mean, 6.0%) in the cervical, thoracic-inlet, and thoracic regions, respectively.
Conclusions and Clinical Relevance—The change in tracheal cross-sectional area from inspiration to expiration was as great as 24% in healthy dogs, and the area was associated with body weight. Respiratory fluctuations appeared to result in changes in tracheal dimension during respiration similar to those reported for humans.
Objective—To define the reference range for laminar blood flow (BF) and vascular permeability (VPM) in horses without laminitis by use of dynamic contrast-enhanced computed tomography (CT).
Animals—9 adult horses that were not lame and had no abnormalities of the laminae or phalanges detectable via radiographic examination.
Procedures—Each horse was anesthetized by use of a routine protocol. Horses were placed in right or left lateral recumbency with the dependent forelimb in the CT gantry; only 1 limb of each horse was scanned. Serial 10-mm collimated transverse CT images were acquired at the same location every other second for 90 seconds during infusion of ionic, iodinated contrast medium. Custom software was used to estimate BF, VPM, and fractional vascular volume (FVV) in the dorsal, dorsomedial, and dorsolateral laminar regions.
Results—Among the 9 horses' forelimbs, mean ± SD dorsal laminar BF was 0.43 ± 0.21 mL•min−1•mL−1. Mean dorsomedial and dorsolateral laminar BFs were 0.26 ± 0.16 mL•min−1•mL−1 and 0.24 ± 0.16 mL•min−1•mL−1, respectively. Mean dorsal laminar VPM was 0.09 ± 0.03 mL•min−1•mL−1. Mean dorsomedial and dorsolateral laminar VPMs were 0.16 ± 0.06 mL•min−1•mL−1 and 0.12 ± 0.06 mL•min−1•mL−1, respectively. Mean dorsal laminar FVV was 0.63 ± 0.20 and dorsomedial and dorsolateral laminar FVV were 0.37 ± 0.14 and 0.34 ± 0.17, respectively.
Conclusions and Clinical Relevance—In horses, laminar BF, VPM, and FVV can be non-invasively measured by use of dynamic contrast-enhanced CT.
Objective—To evaluate the number and types of underlying disorders detected in dogs with aspiration pneumonia and determine the survival rate among affected dogs.
Design—Retrospective case series.
Animals—88 dogs with aspiration pneumonia.
Procedures—Medical records were reviewed to identify disease processes that could result in aspiration pneumonia. To assess outcome (ie, survival to discharge from the hospital or nonsurvival), dogs were grouped by the type and number of underlying disease processes. Duration of hospitalization and radiographic severity of disease were evaluated with regard to case outcome.
Results—As the cause of aspiration pneumonia, a single underlying disorder was identified in 60 of the 88 dogs; 2 or more diseases were identified in the remaining dogs. Esophageal disease (n = 35), vomiting (34), neurologic disorders (24), laryngeal disease (16), and postanesthetic aspiration (12) were identified most commonly. Overall, 68 dogs survived to discharge from the hospital (survival rate, 77%). Survival rates were comparable among dogs regardless of the underlying cause of aspiration pneumonia. Radiographic severity of disease and duration of hospitalization did not influence survival.
Conclusions and Clinical Relevance—Among these study dogs, aspiration pneumonia was associated with a high survival rate. The presence of more than 1 underlying disease associated with aspiration pneumonia did not adversely impact survival rate. Interestingly, radiographic severity of disease and duration of hospitalization were not associated with overall survival rate.
Objective—To evaluate clinical, clinicopathologic, and radiographic findings in dogs with aspiration pneumonia.
Design—Retrospective case series.
Animals—88 dogs with aspiration pneumonia.
Procedures—History, physical examination findings, and clinicopathologic data were obtained from medical records and analyzed for all 88 dogs. Thoracic radiographic findings for all dogs were reviewed to determine the type and location of pulmonary infiltrates.
Results—Aspiration pneumonia was evident at admission to the hospital in 65 (74%) dogs and developed during hospitalization in 23 (26%) dogs. Less than half of these affected dogs had high values for rectal temperature, heart rate, or respiratory rate; however, most (68%) affected dogs had increased, decreased, or adventitious lung sounds. Neutrophilia with a left shift was a common finding. Hypoalbuminemia was detected in 31 of 58 (53%) dogs. Hypoxemia and a high alveolar-arterial gradient in partial pressure of oxygen were detected in 22 of 28 (79%) dogs and 27 of 28 (96%) dogs, respectively. Among the 88 dogs, thoracic radiography revealed a predominantly alveolar infiltrate in 65 (74%) dogs and an interstitial pattern in 23 (26%) dogs; a single lung lobe was affected in 46 (52%) dogs, most commonly the right middle lung lobe (21/46 [46%] dogs).
Conclusions and Clinical Relevance—In dogs, aspiration pneumonia was often associated with abnormalities in pulmonary auscultation in the absence of objective changes in physical examination findings. However, neutrophilia, hypoalbuminemia, and hypoxemia were frequently detected, and radiographic evidence of infiltrates in the right middle lung lobe was common.