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In collaboration with the American College of Veterinary Radiology.

Computed tomographic findings of pulmonary atelectasis in healthy anesthetized Beagles.

OBJECTIVE To characterize the extent and location of atelectasis in healthy anesthetized dogs positioned in lateral recumbency and to determine whether repositioning dogs in sternal recumbency would resolve atelectasis. ANIMALS 6 healthy adult Beagles. PROCEDURES Each dog was anesthetized and underwent a CT examination twice with a 2-week interval between examinations. Once anesthetized, each dog was positioned in sternal recumbency, and a breath-hold helical transverse thoracic CT scan was acquired. The dog was then positioned in lateral recumbency for 30 minutes, and images were obtained at 5 preselected sites at 3, 8, 13, 20, and 30 minutes after repositioning (phase 1). Then, the dog was repositioned in sternal recumbency, and CT images were obtained at the 5 preselected sites at 5, 10, and 20 minutes after repositioning (phase 2). The protocol for the second examination was the same as the first except the dog was positioned in the opposite lateral recumbency during phase 1. The attenuation and cross-sectional area of the lung lobes at the preselected sites were measured and compared over time. RESULTS Lateral recumbency did not cause atelectasis in any of the dogs. Patchy areas of abnormally increased attenuation were infrequently detected in the left cranial lung lobe when dogs were positioned in left lateral recumbency, and those areas failed to resolve when dogs were positioned in sternal recumbency. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent of lung attenuation changes was minimal in healthy anesthetized Beagles positioned in lateral recumbency and should not preclude CT examination.

Oesophagogastric intussusception associated with spirocercosis in a dog.

An oesophagogastric intussusception was diagnosed in an intact Bull Terrier female aged 2 years and 7 months with a concurrent Spirocerca lupi infection. The dog was presented collapsed with a history of inappetance and lethargy of one day's duration. Anaemia and melaena were present on clinical examination. Thoracic radiographs did not reveal any significant findings. Abdominal ultrasound was suspicious for gastric pathology or a possible foreign body. The final diagnosis of an oesophagogastric intussusception with an S. lupi nodule at the cardia was made on post-mortem. Oesophageal intussusceptions are rare in dogs and often fatal. Gastro-oesophageal intussusceptions usually present with obvious radiographic signs in the caudal thorax, unlike an oesophagogastric intussusception, where the pathology lies within the abdomen and may not be readily diagnosed. Although spirocercosis often presents with a caudal oesophageal mass, this may not be seen radiographically. In this case, the two conditions were present together but the thoracic radiographs were normal.An oesophagogastric intussusception was diagnosed in an intact Bull Terrier female aged 2 years and 7 months with a concurrent Spirocerca lupi infection. The dog was presented collapsed with a history of inappetance and lethargy of one day's duration. Anaemia and melaena were present on clinical examination. Thoracic radiographs did not reveal any significant findings. Abdominal ultrasound was suspicious for gastric pathology or a possible foreign body. The final diagnosis of an oesophagogastric intussusception with an S. lupi nodule at the cardia was made on post-mortem. Oesophageal intussusceptions are rare in dogs and often fatal. Gastro-oesophageal intussusceptions usually present with obvious radiographic signs in the caudal thorax, unlike an oesophagogastric intussusception, where the pathology lies within the abdomen and may not be readily diagnosed. Although spirocercosis often presents with a caudal oesophageal mass, this may not be seen radiographically. In this case, the two conditions were present together but the thoracic radiographs were normal.

The comparison of bolus tracking and test bolus techniques for computed tomography thoracic angiography in healthy beagles.

Computed tomography thoracic angiography studies were performed on five adult beagles using the bolus tracking (BT) technique and the test bolus (TB) technique, which were performed at least two weeks apart. For the BT technique, 2 mL/kg of 300 mgI/mL iodinated contrast agent was injected intravenously. Scans were initiated when the contrast in the aorta reached 150 Hounsfield units (HU). For the TB technique, the dogs received a test dose of 15% of 2 mL/kg of 300 mgI/mL iodinated contrast agent, followed by a series of low dose sequential scans. The full dose of the contrast agent was then administered and the scans were conducted at optimal times as identified from time attenuation curves. Mean attenuation in HU was measured in the aorta (Ao) and right caudal pulmonary artery (rCPA). Additional observations included the study duration, milliAmpere (mA), computed tomography dose index volume (CTDI[vol]) and dose length product (DLP). The attenuation in the Ao (BT = 660 52 HU ± 138 49 HU, TB = 469 82 HU ± 199 52 HU, p = 0.13) and in the rCPA (BT = 606 34 HU ± 143 37 HU, TB = 413 72 HU ± 174.99 HU, p = 0.28) did not differ significantly between the two techniques. The BT technique was conducted in a significantly shorter time period than the TB technique (p = 0.03). The mean mA for the BT technique was significantly lower than the TB technique (p = 0.03), as was the mean CTDI(vol) (p = 0.001). The mean DLP did not differ significantly between the two techniques (p = 0.17). No preference was given to either technique when evaluating the Ao or rCPA but the BT technique was shown to be shorter in duration and resulted in less DLP than the TB technique.

The effects of repeated intravenous iohexol administration on renal function in healthy beagles--a preliminary report.

BACKGROUND: Contrast induced nephrotoxicity (CIN) is a well described syndrome in humans undergoing contrast medium examinations. To date CIN has received minimal attention in the veterinary literature despite increasing use of contrast medium examinations in computed tomographic studies. METHODS: This prospective study evaluated the effect of 1290 mg/kg iohexol given intravenously to 5 normal beagle dogs in a divided dose at an interval of 6-8 weeks. Renal function was evaluated by means of scintigraphically determined glomerular filtration rate (GFR) and a variety of laboratory assays. RESULTS: Only GFR showed a significant decrease (17%) after the second injection but not to a clinically or pathologically significant level. CONCLUSIONS: No clinically significant effect of repeated contrast medium administration was determined in this limited study. However in dogs with reduced renal function the risk of CIN is likely to increase dramatically post contrast administration.