Computed tomography, cross sectional anatomy and measurements in the head of normal goats

In der vorliegenden Studie wurden die Köpfe von 30 klinisch gesunden Saanenziegen mit einem Körpergewicht von 50 bis 80 kg mit der Mehrschicht- Computertomographie untersucht. Es wurden Querschnittbilder vor und nach der intravenösen Gabe von Kontrastmittel angefertigt. Anschließend wurden 13 Tiere euthanasiert und tiefgefroren, um 10 mm dicke anatomische Querschnitte der Köpfe herzustellen. Die korrespondierenden CT-Bilder und anatomischen Schnitte wurden verglichen und die anatomischen Strukturen beschriftet. Die Ausdehnung der Sinus und ihrer Öffnungen wurden bestimmt. Die Dichte und Größe der Hypophyse sowie das Verhältnis Hypophysengröße/Hirnfläche wurde gemessen. Bei 2 Ziegen wurde auch eine dynamische CT-Kontrastuntersuchung der Hypophyse durchgeführt. Die meisten Strukturen, die auf den anatomischen Schnitten gesehen wurden, wurden auch auf den CT-Bildern identifiziert. Der vorliegende Bildatlas und die Messungen können als Grundlage dienen, um Erkrankungen im Kopfbereich der Ziege zu diagnostizieren. The present study was performed to provide a detailed anatomic description and computed tomographic (CT) measurements of the structures of the head in 30 clinically normal Saanen goats weighing 50 to 80 kg. Pre- and post-contrast transverse images of the head were obtained with a 40-slice CT scanner. Subsequently, 13 animals were euthanized and frozen. The heads were then sliced into 10 mm transverse sections of which the caudal aspect was photographed. Corresponding CT and anatomic images were compared and labeled. The extensions of the frontal, maxillary, lacrimal and palatine sinuses and the width and location of the openings of the maxillary sinuses and the frontal sinuses were described. The pituitary density and dimensions, pituitary height/brain area ratio as well as the sum of the areas of the lateral ventricles/brain area ratio were measured. In two goats, dynamic CT of the hypophysis was performed. Most features of the head that were identified on anatomic sections could be identified on the corresponding CT scans. In conclusion, the CT images and measurements obtained in this study can be used as a reference for the evaluation of the head in goats with diseases in this region

Computed Tomography-Derived Occipital–Coccygeal Length and Ilium Wing Distance Correlates with Skin to Epidural and Intrathecal Depths in Dogs

The current clinical techniques for neuraxial needle placement in dogs are predominantly blind without prior knowledge of the depth required to reach the desired space. This study investigated the correlation and defined the relationship between easily obtainable external landmark variables in the dog; occipital–coccygeal length (OCL) and ilium wings distance (IWD), with the skin to epidural and intrathecal space distances using computed tomography (CT). The CT images of 86 dogs of different breeds were examined in this retrospective observational study. Images of dogs in sternal recumbency were optimized to the sagittal view. The distances between the skin and lumbosacral epidural space (LSE) and skin to sacrococcygeal space (SCE) were measured to the ligamentum flavum surrogate (LFS) line. The distance between the skin and the intrathecal space (ITS) was measured from the skin to the vertebral canal at the interlumbar (L5–L6) space. Measurements of the IWD and OCL were performed on dorsal and scout views, respectively. Linear regression equations and Pearson’s correlation coefficients were calculated between variables. Data were reported as mean (standard deviation). Significance was set as alpha < 0.05. After exclusion of four dogs, 82 CT scans were included. The depths were LSE 45 (15) mm, SCE 23 (10) mm, and ITS 50 (15) mm. There was a moderate correlation between OCL with LSE (=14.2 + OCL * 0.05 (r = 0.59, p < 0.0001)), and a strong correlation with ITS (=11.4 + OCL * 0.07 (r = 0.76, p < 0.0001)), while a very weak correlation was found with SCE (=14.0 + OCL * 0.02 (r = 0.27, p < 0.0584)). Similarly, with IWD, there was a moderate correlation with LSE (=10.8 + IWD * 0.56 (r = 0.61, p < 0.0001)), and strong correlation with ITS (=9.2 + IWD * 0.67 (r = 0.75, p < 0.0001)), while a weak correlation was found with SCE (=11.2 + IWD * 0.2 (r = 0.32, p < 0.0033)). Mathematical formulae derived from the multiple regression showed that the body condition score (BCS) improved the relationship between IWD and OCL and the LSE, SCE and ITS, while the addition of body weight was associated with multicollinearity. Further studies are required to determine the accuracy of the algorithms to demonstrate their ability for prediction in a clinical setting

Estimation of time to peak contrast enhancement of the aorta and liver for dual-phase computed tomography on the basis of contrast medium arrival time, injection duration, and injection technique in dogs

OBJECTIVE To evaluate the accuracy of estimating time to peak enhancement (TPE) of the aorta and liver parenchyma on the basis of contrast medium arrival time in the aorta, injection duration, and injection technique in dogs. ANIMALS 18 dogs of specific body weight categories (≥ 2 dogs/category) with no liver abnormalities detected via CT. PROCEDURES Dogs were randomly assigned within weight categories to receive contrast medium IV at a fixed injection rate (5 mL/s) or fixed injection duration (20 seconds). Time-contrast attenuation curves were generated from dynamic CT scans acquired at the hepatic hilus. Data collected for contrast medium arrival time and injection duration were used to estimate TPEs of the aorta and liver, and results were compared with the observed TPEs for the aorta and liver. RESULTS Contrast medium arrival time, injection duration, and injection technique were significantly associated with observed values for aortic TPE and explained 96.1% of variation in TPE. For the fixed rate technique, the regression equation for estimating aortic TPE was 0.8 X (injection duration + contrast medium arrival time) + 1.6. For the fixed duration technique, the regression equation changed by only the constant (-2.6). However, the hepatic TPE estimated from the 3 predictor variables was not significantly different from the mean of observed TPEs. CONCLUSIONS AND CLINICAL RELEVANCE Aortic TPE could be accurately estimated from contrast medium arrival time, injection duration, and injection technique in dogs with apparently healthy livers. The regression equations derived from this relationship can be used to improve the efficiency of dual-phase CT of the liver in dogs

Use of gadoxetic acid for computed tomographic cholangiography in healthy dogs

OBJECTIVE To evaluate the effect of gadoxetic acid (contrast) dose on biliary tract enhancement, determine the optimal time after contrast injection for CT image acquisition, and assess the feasibility of CT cholangiography in sedated dogs. ANIMALS 8 healthy dogs. PROCEDURES The study had 2 parts. In part 1, 4 dogs were anesthetized and underwent CT cholangiography twice. Gadoxetic acid was administered IV at a low dose (0.025 mmol/kg) for the first procedure and high dose (0.3 mmol/ kg) for the second procedure. Serial CT scans were obtained at predetermined times after contrast injection. In part 2, 4 dogs were sedated and underwent CT angiography 85 minutes after IV administration of the high contrast dose. Contrast enhancement of the biliary tract on all scans was objectively assessed by measurement of CT attenuation and qualitatively assessed by use of a subjective 4-point scoring system by 3 independent reviewers. All measurements were compared over time and between contrast doses for the dogs of part 1. Subjective measurements were compared between the sedated dogs of part 2 and anesthetized dogs of part 1. RESULTS Enhancement of the biliary tract was positively associated with contrast dose and time after contrast injection. Optimal enhancement was achieved 65 minutes after contrast injection. Subjective visualization of most biliary structures did not differ significantly between sedated and anesthetized dogs. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated CT cholangiography with gadoxetic acid was feasible in sedated dogs. The high contrast dose provided better visualization of biliary structures than the low dose; CT scans should be obtained 65 minutes after contrast injection

Pulmonary hypertension

OBJECTIVES: The purposes of this study were to evaluate if (1) Angiostrongylus vasorum-infected dogs recruit pulmonary arteriovenous (AV) shunts attenuating the development of pulmonary hypertension (PH), detectable using saline contrast echocardiography, (2) anthelmintic therapy causes an acute increase in pulmonary arterial pressure (PAP), (3) Tissue Doppler Imaging (TDI) allows detection of mild changes in right ventricular function secondary to pulmonary (vascular) disease. ANIMALS: 6 healthy Beagle dogs, each infected with 200 A. vasorum larvae. METHODS: Conventional, TDI and contrast echocardiography, invasive PAP measurements before (T0), 7-12 weeks post infection (wpi, T1), and 1-5 days post therapy (dpt, T2). RESULTS: All dogs had patent infections 7-8 wpi and respiratory signs 6-9 wpi. PAP was mildly but significantly increased at T2. Saline contrast echo was positive in 3/6 dogs at T1 and 4/6 dogs at T2. Pulmonary transit time did not change. Of all numeric echocardiographic parameters, only a non-significant decrease in the E' wave and inversion of E'/A' ratio in 3 dogs at T2 could be observed. Two of these had mild PH and negative saline contrast echocardiography. CONCLUSION: A. vasorum infection causes only a mild increase in PAP following inoculation and anthelmintic therapy. The absence of important PH may in part be explained by the recruitment of AV shunts in the presence of vascular obstructive disease. TDI echocardiographic parameters may be more sensitive to detect mild changes in RV function than conventional parameters

Effect of contrast medium injection duration on peak enhancement of canine pulmonary arteries

Our goal was to investigate the effect of contrast medium injection duration on pulmonary artery peak enhancement and time to peak enhancement. Fourteen dogs were allocated into one of seven predefined weight categories, each category contained two dogs. Dogs in each weight category were assigned to group A or B. Animals in each group received a different contrast medium injection protocol. In group A, a fixed injection rate of 5ml/s was used. In group B, the contrast injection rate was calculated as follows: flow rate1⁄4contrast volume/scan durationþ10s. Time to peak enhancement and peak enhancement of the main left and right pulmonary arteries were measured on single-level, dynamic CT images for a fixed time of 30 s. Rank correlation (Spearman’s) coefficients between injection duration and time to peak enhancement and between body weight and peak enhancement were calculated. For group A, there was a significant negative correlation between peak enhancement and weight (r1⁄

Disseminated Scedosporium prolificans infection in a Labrador retriever with immune mediated haemolytic anaemia

Disseminated scedosporiosis is rare in dogs and is usually reported in German Shepherds with suspected heritable immunodeficiency. This is the first report of disseminated scedosporiosis due to Scedosporium prolificans in a Labrador retriever dog that was receiving immunosuppressive drug therapy for treatment of immune-mediated haemolytic anaemia. Despite cessation of immunosuppressive medications and an initial response to aggressive treatment with voriconazole and terbinafine the dog developed progressive disease with neurological signs necessitating euthanasia six months from diagnosis