HELICAL COMPUTED TOMOGRAPHIC ANGIOGRAPHY OF THE NORMAL CANINE PANCREAS

Computed tomographic measurements of pancreatic thickness in clinically normal dogs

Pancreatic thickness is an indicator for evaluating pancreatic diseases. The transverse and cross-sectional pancreatic thickness observed on computed tomography (CT) may differ. This study aimed to provide a normal reference range for pancreatic thickness on the transverse plane based on body weight (BW) and assess pancreatic thickness to aorta (P/Ao) ratio. In addition, we aimed to establish the normal short and long dimensions of the pancreas based on cross-sectional image through the long axis of the pancreas using multiplanar reconstruction (MPR). The short dimension to aorta (S/Ao) and long dimension to aorta (L/Ao) ratios were also established in clinically normal dogs. The pancreatic thickness was measured using CT results of 205 clinically normal dogs. The pancreatic thickness on the transverse plane and the short and long dimensions in the cross-sectional image of the pancreas were measured using MPR. The diameter of the Ao was measured on the transverse plane and the P/Ao, S/Ao, and L/Ao ratios were calculated. Our study showed that the mean normal pancreatic thicknesses (mean ± standard deviation [SD]) of the pancreatic body, left and right lobe in the transverse plane were 10.92 ± 2.54 mm, 8.92 ± 2.26 mm and 9.96 ± 2.24 mm, respectively. The P/Ao ratios of the pancreatic body, left and right lobes were 1.85 ± 0.33, 1.50 ± 0.27 and 1.68 ± 0.29, respectively. The mean short dimension (mean ± SD) in the cross-sectional image of the pancreatic body, left and right lobe were 8.98 ± 1.97 mm, 7.99 ± 1.89 mm and 8.76 ± 2.03 mm, respectively. In conclusion, pancreatic thickness increased with BW, while the P/Ao, S/Ao, and L/Ao ratios could be used regardless of BW.

Computed tomographic evaluation of pancreatic perfusion in 10 dogs with acute pancreatitis

Severe canine acute pancreatitis can be fatal; imaging features that can predict the clinical course of disease are useful for clinicians. On computed tomography (CT), both pancreatic heterogeneous contrast enhancement and portal vein thrombosis have been correlated with poorer outcome. Perfusion CT is used in human medicine to evaluate pancreatic microcirculation to predict the future development of severe sequela to pancreatitis; this technology has yet to be explored in dogs with acute pancreatitis. The objective of this prospective, case-control study is to evaluate pancreatic perfusion using contrast-enhanced CT in dogs with acute pancreatitis and compare it with previously established values obtained in healthy dogs. Ten client-owned dogs preliminarily diagnosed with acute pancreatitis received a full abdominal ultrasound, specific canine pancreatic lipase (Spec cPL), and perfusion CT. Computer software calculated pancreatic perfusion, peak enhancement index, time to peak enhancement, and blood volume for 3-mm and reformatted 6-mm slices. The data was analyzed using Shapiro-Wilk test, linear mixed model, and Spearman's rho. Values for 3-mm slices were similar to 6-mm slices (all P < 0.05). Dogs with acute pancreatitis had a faster time to peak enhancement than healthy dogs (P = 0.04-0.06). Dogs with acute pancreatitis and homogeneous pancreatic enhancement had higher perfusion, faster time to peak enhancement, and greater blood volume compared to healthy dogs and dogs with acute pancreatitis and heterogeneous pancreatic enhancement (all P = / < 0.05). Pancreatic perfusion decreased with increased pancreatitis severity. No correlation was identified between Spec cPL and pancreatic perfusion (all P > 0.05). These findings preliminarily support perfusion CT in dogs with acute pancreatitis.

Advances in the diagnosis of acute pancreatitis in dogs

In the last 20 years, the diagnosis of pancreatitis has become more frequent as a result of improved diagnostic modalities such as abdominal ultrasound examination, advanced imaging, and immunoassays for the measurement of pancreatic lipase. Our aim is to provide a state‐of‐the‐art overview of the clinical diagnosis of acute pancreatitis (AP) in dogs with a particular focus on pancreatic lipase assay validation and clinical performance, in addition to advanced imaging modalities. We also discuss the potential indications for cytology and histopathology in dogs with suspected AP.

Morphometrical Study of the Lumbar Segment of the Internal Vertebral Venous Plexus in Dogs: A Contrast CT-Based Study

Simple Summary

The internal vertebral venous plexus (IVVP) is a valveless venous network running inside the vertebral canal. The objective of this study was to morphometrically describe the IVVP, dural sac, epidural space and vertebral canal of the lumbar segment in dogs with enhanced computerized tomography. Six clinically healthy adult dogs were used for the study. Dorsal reconstructed computed tomography (CT) images showed a continuous rhomboidal morphological pattern for the IVVP. The dural sac was observed as an isodense structure with a rounded shape throughout the vertebral canal. The average percentage area occupied by the IVVP between L1 and L7 vertebrae ranged between 6.3% and 8.9% of the area of the vertebral canal, and the dural sac ranged between 13.8% and 72.2% of the vertebral canal. The epidural space accounted between 27.08% and 86.2% of the lumbar vertebral canal. CT venography is a safe technique that allows adequate visualization and evaluation of the lumbar IVVP and adjacent structures in dogs.

Abstract

The internal vertebral venous plexus (IVVP) is a thin-walled, valveless venous network that is located inside the vertebral canal, communicating with the cerebral venous sinuses. The objective of this study was to perform a morphometric analysis of the IVVP, dural sac, epidural space and vertebral canal between the L1 and L7 vertebrae with contrast-enhanced computed tomography (CT). Six clinically healthy adult dogs weighing between 12 kg to 28 kg were used in the study. The CT venographic protocol consisted of a manual injection of 880 mgI/kg of contrast agent (587 mgI/kg in a bolus and 293 mgI/mL by continuous infusion). In all CT images, the dimensions of the IVVP, dural sac, and vertebral canal were collected. Dorsal reconstruction CT images showed a continuous rhomboidal morphological pattern for the IVVP. The dural sac was observed as a rounded isodense structure throughout the vertebral canal. The average area of the IVVP ranged from 0.61 to 0.74 mm² between L1 and L7 vertebrae (6.3–8.9% of the vertebral canal), and the area of the dural sac was between 1.22 and 7.42 mm² (13.8–72.2% of the vertebral canal). The area of the epidural space between L1 and L7 ranged from 2.85 to 7.78 mm² (27.8–86.2% of the vertebral canal). This CT venography protocol is a safe method that allows adequate visualization and morphometric evaluation of the IVVP and adjacent structures.

Early partial portal venous contrast enhancement in canine CT-Angiography

Early partial portal vein contrast enhancement (EPoVE) during the late arterial phase is seen in CT angiography of dogs. Previously, it has been a finding attributed to arterioportal vascular anomalies. However, EPoVE may be a normal feature of venous return from abdominal organs. This prospective, descriptive study investigated the origin of EPoVE using four-dimensional CT (4D-CT). Sixteen dogs undergoing 4D-CT for disease of the cranial abdomen were prospectively collected. Regions of interest were placed in the hepatic artery (HA), gastroduodenal vein (GV), extrahepatic portal vein (EHPV) cranial and caudal to the GV, and splenic vein (SV) caudal to its EHPV entry. Times to earliest, partial, full, and maximal vascular enhancement were recorded. A mixed model analysis of variance was used to compare time-to-contrast enhancement between vessels. The number, origin, and time of EPoVE were recorded if visible. A total of 24 EPoVE areas were observed in all dogs. Most dogs had either one (10/16) or two (5/16) areas of EPoVE. The origin of EPoVE was identified in 14 of 24 areas: the GV in five areas, cranial mesenteric vein in four areas, pancreatic branch of SV in three areas, and SV in two areas. The time-to-contrast-enhancement was significantly different for the individual veins compared to the HA. EPoVE during the late arterial phase is a common phenomenon of early portal venous drainage of abdominal organs; it should not be interpreted as pathognomonic for arterioportal vascular anomalies, which should be diagnosed based on additional criteria.

Computed tomographic evaluation of pancreatic perfusion in healthy dogs

OBJECTIVE

To evaluate the feasibility of contrast-enhanced CT for assessment of pancreatic perfusion in healthy dogs.

ANIMALS

6 healthy purpose-bred female Treeing Walker Coonhounds.

PROCEDURES

Contrast-enhanced CT of the cranial part of the abdomen was performed with 3-mm slice thickness. Postprocessing computer software designed for evaluation of human patients was used to calculate perfusion data for the pancreas and liver by use of 3-mm and reformatted 6-mm slices. Differences in perfusion variables between the pancreas and liver and differences in liver-specific data of interest were evaluated with the Friedman test.

RESULTS

Multiple pancreatic perfusion variables were determined, including perfusion, peak enhancement index, time to peak enhancement, and blood volume. The same variables as well as arterial, portal, and total perfusion and hepatic perfusion index were determined for the liver. Values for 6-mm slices appeared similar to those for 3-mm slices. The liver had significantly greater median perfusion and peak enhancement index, compared with the pancreas.

CONCLUSIONS AND CLINICAL RELEVANCE

Measurement of pancreatic perfusion with contrast-enhanced CT was feasible in this group of dogs. Hepatic arterial and pancreatic perfusion values were similar to previously published findings for dogs, but hepatic portal and hepatic total perfusion measurements were not. These discrepancies might have been attributable to physiologic differences between dogs and people and related limitations of the CT software intended for evaluation of human patients. Further research is warranted to assess reliability of perfusion variables and applicability of the method for assessment of canine patients with pancreatic abnormalities.

CT angiographic changes in dogs with acute pancreatitis: A prospective longitudinal study

Computed tomographic angiography (CTA) has recently been shown to be a useful tool in the diagnosis of acute canine pancreatitis, the identification of pancreatic necrosis, and the detection of sequelae. Evidence of pancreatic necrosis on CTA has been shown to be correlated with a poorer outcome in both humans and dogs and early diagnosis and intervention may improve outcomes. In humans, pancreatic necrosis is typically evident on CTA within 48 h of clinical signs, thus, repeat CTA examinations are often performed to identify pancreatic necrosis that may not have been evident on CTA examinations performed early in the course of disease. Published information investigating the timing of CTA examinations and the use of serial CTA in dogs with acute pancreatitis is lacking. In this prospective, longitudinal study, CTA examinations were performed at the time of hospitalization and repeated 3-5 days later in 11 dogs suffering from acute canine pancreatitis to determine if pancreatic necrosis or sequelae are under diagnosed on examinations performed at the time of hospitalization. Computed tomographic angiography studies were evaluated for changes in pancreatic size, pancreatic contrast enhancement, and peri-pancreatic tissues and vessels. The only statistically significant difference between the initial and repeat CTA examinations was the improvement of fat stranding on the repeat CTA examinations (P < .045). Based on these results, CTA performed at the time of admission is likely adequate in the diagnosis and evaluation of dogs with acute pancreatitis. Repeat CTA examinations are unlikely to add additional information in the absence of worsening clinical signs.

Computed tomographic angiography and ultrasonography in the diagnosis and evaluation of acute pancreatitis in dogs

Background

Acute pancreatitis in dogs is an under‐diagnosed disease. Current diagnostic methods are insufficient at identifying sequelae and lack prognostic capability. Computed tomographic angiography (CTA) is accurate for diagnosis and prognostication of pancreatitis in humans.

Objectives

In comparison to ultrasound (US), CTA will (1) better diagnose more severe pancreatitis and sequelae and (2) provide assessment of patient outcome by identification of pancreatic contrast enhancement patterns.

Animals

Twenty‐six client‐owned dogs suspected to have acute pancreatitis.

Methods

US and CTA examinations performed at time of admission were compared to determine the detection of pancreatic changes and sequelae. CTA findings also were compared to outcome indicators for prognosis of dogs with acute pancreatitis. Specific canine pancreatic lipase (cPL) samples were obtained and compared with CTA findings.

Results

Ten of 26 dogs had heterogeneous contrast enhancement of the pancreas. Compared to US, CTA better identified portal vein thrombosis (P = .003). Patients with heterogeneous contrast enhancement had longer hospitalization (P = .01), including hospital stays for >5 days (P = .02), had more relapses, and were more likely to have portal vein thrombosis (P = .002). Patients with heterogeneous contrast enhancement had increased spec cPL (P = .006).

Conclusions and Clinical Importance

In comparison to US, CTA better identified dogs with more severe acute pancreatitis and those with portal vein thrombosis, factors that may predict longer hospitalization and increased risk of relapse. The presence of heterogeneous contrast enhancement and portal vein thrombosis may change therapy for patients with acute pancreatitis.

Evaluation of canine hepatic masses by use of triphasic computed tomography and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography and correlation with histopathologic classification

OBJECTIVE To determine clinical relevance for quantitative and qualitative features of canine hepatic masses evaluated by use of triphasic CT and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography and to compare diagnostic accuracy of these modalities for predicting mass type on the basis of histopathologic classification. ANIMALS 44 client-owned dogs. PROCEDURES Dogs with histopathologic confirmation (needle core, punch, or excisional biopsy) of a hepatic mass were enrolled. Triphasic CT and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography of each hepatic mass were performed. Seventy quantitative and qualitative variables of each hepatic mass were recorded by 5 separate observers and statistically evaluated with discriminant and stepwise analyses. Significant variables were entered in equation-based predictions for the histopathologic diagnosis. RESULTS An equation that included the lowest delayed-phase absolute enhancement of the mass and the highest venous-phase mass conspicuity was used to correctly classify 43 of 46 (93.5%) hepatic masses as benign or malignant. An equation that included only the lowest delayed-phase absolute enhancement of the mass could be used to correctly classify 42 of 46 (91.3%) masses (with expectation of malignancy if this value was < 37 Hounsfield units). For ultrasonography, categorization of the masses with cavitations as malignant achieved a diagnostic accuracy of 80.4%. CONCLUSIONS AND CLINICAL RELEVANCE Triphasic CT had a higher accuracy than ultrasonography for use in predicting hepatic lesion classification. The lowest delayed-phase absolute enhancement of the mass was a simple calculation that required 2 measurements and aided in the differentiation of benign versus malignant hepatic masses.

Triple phase computed tomography of the pancreas in healthy cats

While the availability and use of computed tomography (CT) continues to grow, no study has described the size and multiphase CT appearance of the normal feline pancreas. This information is important to not only allow more accurate identification and differentiation of disease, but it may also be useful in assessing pancreatic function. In this prospective analytical study, we described a triple phase CT protocol of the pancreas for use in sedated cats and the attenuation, enhancement pattern, size, and volume of the pancreas for a group of healthy cats. Fifteen healthy cats were enrolled in the study and a standardized protocol for acquiring arterial, portal, and delayed phase CT images of the pancreas was developed and described. The pancreas was hypo to isoattenuating to both the liver and spleen in all phases in the majority of cats with a homogenous enhancement pattern noted in all 15. Mean pancreatic attenuation was 48, 79, 166, and 126 Hounsfield units (HU) respectively on precontrast, arterial, portal, and delayed phase images. In addition, mean height, length, and width of the left lobe of the pancreas were larger than the right lobe in all 15 cats. There were no associations between volume and volume: body weight ratio with age (P = 0.6518, P = 0.6968) or sex (P = 0.7013, P = 0.2043). This baseline information may be beneficial for use in future studies characterizing pancreatic disease in cats as well as future research studies evaluating pancreatic endocrine function.

Optimal scan delay depending on contrast material injection duration in abdominal multi-phase computed tomography of pancreas and liver in normal Beagle dogs

This study was conducted to establish the values for optimal fixed scan delays and diagnostic scan delays associated with the bolus-tracking technique using various contrast material injection durations in canine abdominal multi-phase computed tomography (CT). This study consisted of two experiments employing the crossover method. In experiment 1, three dynamic scans at the porta hepatis were performed using 5, 10 and 15 sec injection durations. In experiment 2, two CT scans consisting of five multi-phase series with different scan delays of 5 sec intervals for bolus-tracking were performed using 5, 10 and 15 sec injection duration. Mean arrival times to aortic enhancement peak (12.0, 15.6, and 18.6 sec for 5, 10, and 15 sec, respectively) and pancreatic parenchymal peak (17.8, 25.1, and 29.5 sec) differed among injection durations. The maximum mean attenuation values of aortas and pancreases were shown at the scan section with 0 and 5, 0 and 10 and 5 and 10 sec diagnostic scan delays during each injection duration, respectively. The optimal scan delays of the arterial and pancreatic parenchymal phase in multi-phase CT scan using fixed scan delay or bolus-tracking should be determined with consideration of the injection duration.

Diagnostic Imaging of the Hepatobiliary System: An Update

Recent advances in diagnostic imaging of the hepatobiliary system include MRI, computed tomography (CT), contrast-enhanced ultrasound, and ultrasound elastography. With the advent of multislice CT scanners, sedated examinations in veterinary patients are feasible, increasing the utility of this imaging modality. CT and MRI provide additional information for dogs and cats with hepatobiliary diseases due to lack of superimposition of structures, operator dependence, and through intravenous contrast administration. Advanced ultrasound methods can offer complementary information to standard ultrasound imaging. These newer imaging modalities assist clinicians by aiding diagnosis, prognostication, and surgical planning.

Perfusion CT - Can it resolve the pancreatic carcinoma versus mass forming chronic pancreatitis conundrum?

OBJECTIVES

To evaluate the utility of perfusion CT (PCT) in differentiating pancreatic adenocarcinoma from mass forming chronic pancreatitis (MFCP).

METHODS

In this ethically approved study, PCT was performed in 122 patients with pancreatic masses of which 42 patients had pancreatic adenocarcinoma and 13 had MFCP on histopathology. Perfusion parameters studied included blood flow (BF), blood volume (BV), permeability surface area product (PS), time to peak (TTP), peak enhancement intensity (PEI) and mean transit time (MTT). Twenty five controls with no pancreatic pathology were also studied.

RESULTS

Amongst the perfusion parameters BF and BV were found to be the most reliable for differentiating between adenocarcinoma and mass forming pancreatitis. Although they were reduced in both pancreatic adenocarcinoma (BF- 16.6 ± 13.1 ml/100 ml/min and BV- 5 ± 3.5 ml/100 ml) and MFCP (BF- 30.4 ± 8.7 ml/100 ml/min and BV- 8.9 ± 3.1 ml/100 ml) as compared to normal controls (BF- 94.1 ± 24 ml/100 ml/min and BV- 36 ± 10.7 ml/100 ml) but the extent of reduction was greater in pancreatic adenocarcinoma than in MFCP. Based on ROC analysis cut off values of 19.1 ml/100 ml/min for BF and 5 ml/100 ml for BV yielded optimal sensitivity and specificity for differentiating pancreatic adenocarcinoma from MFCP.

CONCLUSIONS

PCT may serve as an additional paradigm for differentiating pancreatic adenocarcinoma from mass forming chronic pancreatitis and a useful tool for detecting masses which are isodense on conventional CT.

Computed Tomography and MRI of the Hepatobiliary System and Pancreas

MRI and computed tomographic (CT) imaging are becoming more common in the diagnosis of hepatobiliary and pancreatic disorders in small animals. With the advent of multislice CT scanners, sedated examinations in veterinary patients are feasible increasing the use of this imaging modality. CT and MRI provide additional information for dogs and cats with hepatobiliary and pancreatic diseases because of lack of superimposition of structures, operator dependence, and through intravenous contrast administration. This added value provides more information for diagnosis, prognosis, and surgical planning.

Establishment of optimal scan delay for multi-phase computed tomography using bolus-tracking technique in canine pancreas

To establish a protocol for a multi-phase computed tomography (CT) of the canine pancreas using the bolus-tracking technique, dynamic scan and multi-phase CT were performed in six normal beagle dogs. The dynamic scan was performed for 60 sec at 1-sec intervals after the injection (4 ml/sec) of a contrast medium, and intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were measured. The multi-phase CT with 3 phases was performed three times using a bolus-tracking technique. Scan delays were 0, 15 and 30 in first multi-phase scan; 5, 20 and 35 in second multi-phase scan; and 10, 25 and 40 sec in third multi-phase scan, respectively. Attenuation values and contrast enhancement pattern were analyzed from the aorta, pancreas and portal vein. The intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were 3.8 ± 0.7, 8.7 ± 0.9 and 13.3 ± 1.5 sec, respectively. The maximum attenuation values of the aorta, pancreatic parenchyma and portal vein were present at scan sections with no scan delay, a 5-sec delay and a 10-sec delay, respectively. When a multi-phase CT of the canine pancreas is triggered at aortic enhancement appearance using a bolus-tracking technique, the recommended optimal delay times of the arterial and pancreatic parenchymal phases are no scan delay and 5 sec, respectively.

Computed tomographic angiography under sedation in the diagnosis of suspected canine pancreatitis: a pilot study

Background

Computed tomography (CT) is highly accurate for diagnosing pancreatitis in humans. The diagnosis of pancreatitis in dogs is based on clinical signs, laboratory findings, and ultrasonographic (US) changes. There are, however, inherent limitations in relying on laboratory and ultrasound findings for the clinical diagnosis of pancreatitis in dogs.

Hypothesis/Objectives

We hypothesized that CT angiography would be a rapid and reliable method to confirm pancreatitis in dogs compared to ultrasonography. The aim was to describe the CT characteristics and compare them to ultrasound findings and correlate the CT appearance to the severity of the patients' clinical course.

Animals

A prospective pilot case series; 10 dogs with pancreatitis were enrolled if the history, clinical signs, laboratory, and ultrasonographic findings were indicative of pancreatitis.

Methods

A 3‐phase angiographic CT was performed under sedation. Afterward, each dog had US‐guided aspirates of the pancreas collected and blood drawn for cPLi assay. Images were evaluated for portion of visible pancreas, pancreatic size and margin, pancreatic parenchyma, presence of peripancreatic changes and contrast enhancement pattern. The results were compared with outcome.

Results

An enlarged, homogeneously to heterogeneously attenuating and contrast‐enhancing pancreas with ill‐defined borders was identified in all dogs. CT identified more features characterizing pancreatic abnormalities compared to US. Thrombi were found in 3/10 dogs. Three dogs with heterogeneous contrast enhancement had an overall poorer outcome than those with homogenous enhancement.

Conclusions and Clinical Importance

CT angiography under sedation was used in dogs to confirm clinically suspected pancreatitis and identified clinically relevant and potentially prognostic features of pancreatitis in dogs.

Comparison between survey radiography, B-mode ultrasonography, contrast-enhanced ultrasonography and contrast-enhanced multi-detector computed tomography findings in dogs with acute abdominal signs

Contrast-enhanced multi-detector computed tomography (CE-MDCT) is used routinely in evaluating human patients with acute abdominal symptoms. Contrast-enhanced ultrasound (CEUS) continues to be in its infancy as it relates to evaluation of the acute abdomen. The purpose of this study was to compare survey radiography, B-mode ultrasound, CEUS, and CE-MDCT findings in canine patients presenting with acute abdominal signs; with a focus on the ability to differentiate surgical from non-surgical conditions. Nineteen dogs were prospectively enrolled. Inclusion required a clinical diagnosis of acute abdominal signs and confirmed surgical or non-surgical causes for the clinical signs. Agreement for the majority of recorded imaging features was at least moderate. There was poor agreement in the identification of pneumoperitoneum and in the comparison of pancreatic lesion dimensions for B-mode vs. CEUS. The CT feature of fat stranding was detected in cases including, but not limited to, gastric neoplasia with perforation, pancreatitis, and small intestinal foreign body. Ultrasound underestimated the size and number of specific lesions when compared with CE-MDCT. Contrast-enhanced ultrasound was successful in detecting bowel and pancreatic perfusion deficits that CE-MDCT failed to identify. Accuracy for differentiation of surgical vs. non-surgical conditions was high for all modalities; 100%, 94%, and 94% for CE-MDCT, ultrasonography and survey radiography respectively. Findings indicated that CE-MDCT is an accurate screening test for differentiating surgical from non-surgical acute abdominal conditions in dogs. Focused CEUS following CE-MDCT or B-mode ultrasonography may be beneficial for identifying potentially significant hypoperfused lesions.

Quantitative computed tomography of the liver in dogs submitted to prednisone therapy

The aim of this study is to evaluate the possible alterations in radiodensity of the hepatic parenchyma and spleen resulting from the corticotherapy with prednisone, correlating these findings with serum biochemical hepatic transaminase activity. A clinical trial was performed on eight healthy dogs with the intent of evaluating possible hepatic alterations after prednisone therapy using quantitative computed tomography. All animals received prednisone orally at a dose of 2mg/kg of weight for 30 days. The radiodensity of the liver and spleen was determined before and after the period that the medication was administered. An increase in the radiodensity of the hepatic parenchyma between the initial and final experimental stages was observed. In the present study the existence of early hepatic alterations were verified, which are compatible with glycogen storage.

Comparison between bolus tracking and timing-bolus techniques for renal computed tomographic angiography in normal cats

Renal dual-phase computed tomograpic angiography (CTA) is used to assess suitability of feline donors prior to transplantation. A prerequisite for successful CTA is optimal synchronization between the arterial passage of contrast material and CT data acquisition. This retrospective study was conducted to compare quality of renal vascular enhancement at dual-phase CTA in normal cats between two techniques of timing of data acquisition: the timing-bolus and the bolus tracking method. Nine cats were scanned using the timing-bolus technique and 14 with the bolus tracking technique using otherwise similar scanning parameters in a 16-slice multidetector row CT scanner. The quality of enhancement of the renal vessels at the scanned arterial phase and venous phase was assessed both subjectively and objectively by three board-certified radiologists. Arterial enhancement was not observed at the scanned arterial phase in three of the nine cats with the timing-bolus technique but only 1 of the 14 cats with the bolus tracking technique. Early venous enhancement at the scanned arterial phase was common with the bolus tracking technique. Data acquisition was significantly faster with the bolus tracking technique. We conclude that the bolus tracking technique is a valid technique that could be integrated into the routine protocol for 16-detector row CT renal angiography in cats.

Feasibility for using dual-phase contrast-enhanced multi-detector helical computed tomography to evaluate awake and sedated dogs with acute abdominal signs

Canine patients with acute abdominal signs are often clinically unstable and need a rapid and accurate diagnosis. Contrast-enhanced multi-detector computed tomography (CT) is the current modality of choice for evaluating acute abdominal pain in people. We hypothesized that contrast-enhanced multi-detector CT would be a feasible and safe technique for use in awake and lightly sedated dogs with acute abdominal signs. Eighteen client-owned dogs were enrolled, all presenting with acute abdominal signs. Dogs were scanned using a dual-phase protocol that included precontrast, arterial, and portal venous phases. Eight dogs were scanned awake and ten were given light sedation as chosen by the primary care clinician. Two observers who were unaware of clinical findings and sedation status scored image quality for each scan by consensus opinion. Mean serum creatinine in the sedated group was higher than in the awake group but was within the normal reference range. Other laboratory and physiologic measures did not differ between awake and sedated groups. No IV contrast-related adverse reactions were seen. Median scan time for all patients was less than 10 min. Sixteen of 18 contrast-enhanced multi-detector CT scans were scored fair to excellent in diagnostic quality, with no statistical difference in diagnostic quality for awake vs. sedated patients. Causes for two poor quality diagnostic scans included severe beam hardening from previously administered barium contrast agent and severe motion artifacts. We conclude that dual-phase contrast-enhanced multi-detector CT is a feasible and safe technique for evaluating awake and minimally sedated dogs presenting with acute abdominal signs.

Computed tomography in the diagnosis of steroidal hepatopathy in a dog: case report

It is reported a case of an eight-year-old Yorkshire Terrier dog, with a history of prolonged use of prednisone in a dosage of 1mg/kg of body weight each 24 hours during two years. The helical computed tomography revealed hepatomegaly associated to a hyperattenuation of the parenchyma, with a radiodensity value of 82.55 Hounsfield units (HU). The spleen presented a mean radiodensity of 57.17HU, and a radiodensity difference of 25.38HU was observed between the two organs. Based on the history and findings of imaging technique, it was determined the presumptive diagnosis of steroidal hepatopathy compatible with accumulation of hepatic glycogen. It was concluded that computed tomography enabled the characterization of hepatic injury and the presumed diagnosis of steroidal hepatopathy

64-slice CT perfusion imaging of pancreatic adenocarcinoma and mass-forming chronic pancreatitis

RATIONALE AND OBJECTIVES

To investigate 64 computed tomography (CT) perfusion imaging features of patients with pancreatic cancer and mass-forming chronic pancreatitis.

MATERIALS AND METHODS

Between January 2003 and April 2010, 234 patients with pancreatic mass underwent 64-CT perfusion imaging. Among them, the histopathological results of 64 patients were proven to be pancreatic adenocarcinoma and 15 patients were proven to be mass-forming chronic pancreatitis. Additionally, CT perfusion imaging was performed in 33 healthy volunteers served as controls. The slice data were processed using CT perfusion software. Perfusion parameters including time density curve, blood flow, blood volume, permeability, peak enhancement, and time to peak were recorded.

RESULTS

Blood flow was 77% lower in patients with pancreatic adenocarcinoma than in controls, 48% lower in patients with mass-forming chronic pancreatitis than in controls, and 56% lower in patients with pancreatic adenocarcinoma than with mass-forming chronic pancreatitis (P < .016). Blood volume was 65% lower in pancreatic adenocarcinoma than in controls, 27% lower in mass-forming chronic pancreatitis than in controls, and 53% lower in cancer than mass-forming chronic pancreatitis (P < .016). Permeability was 559% higher in pancreatic adenocarcinoma than in controls, 821% higher in mass-forming chronic pancreatitis than in controls, and 28% lower in cancer than mass-forming chronic pancreatitis (P < .016). Peak enhancement was 27% lower and time to peak 23% longer in pancreatic adenocarcinoma than mass-forming chronic pancreatitis (P < .016). Time-density curve showed the peak of mass-forming chronic pancreatitis is earlier and higher than that of pancreatic adenocarcinoma, and the peak of mass-forming chronic pancreatitis is later and lower than that of controls.

CONCLUSION

CT perfusion imaging can provide additional quantitative hemodynamic information of pancreatic adenocarcinoma and mass-forming chronic pancreatitis.

Distal abdominal aortic thrombosis diagnosed by three-dimensional contrast-enhanced magnetic resonance angiography

Contrast enhanced magnetic resonance angiography (MRA) can provide noninvasive relatively rapid three-dimensional high-detailed vascular images over large anatomic areas. There are few descriptions of the use of contrast-enhanced MRA in veterinary patients. This is a report illustrating the use of contrast-enhanced MRA to localize the full extent of distal aortic, external iliac, and femoral artery thrombi confirmed surgically in four dogs. Distal aorta contrast-enhanced MRA was anatomically accurate in detecting the full extent of thrombi involving the aorta, external iliac and femoral arteries in these four canine patients. This procedure can provide important information for surgery.

Pancreatic adenocarcinoma: dynamic 64-slice helical CT with perfusion imaging

BACKGROUND

Perfusion CT is able to outline blood perfusion changes in a tissue. Thus, in lesions of the tissues of the pancreas, this offers to increase the accuracy of CT diagnosis. In this study, our aim was to explore the perfusion characteristics of normal pancreas and pancreatic adenocarcinoma.

METHODS

Dynamic 64-slice helical CT was conducted in 36 patients with non-pancreatic disease and in 40 patients with histopathologically proven pancreatic adenocarcinoma. Perfusion parameters including blood flow (BF), blood volume (BV), and permeability surface area product (PS) were recorded.

RESULTS

There was no significant difference noted between the distribution of BF, BV, and PS values in different regions of the pancreas, namely the head, neck, body, and tail (P > 0.05). The BF, BV, and PS of normal pancreas were recorded as 135.24 +/- 48.36 ml min(-1) 100 g(-1), 200.55 +/- 54.96 ml 100 g(-1), and 49.75 +/- 24.27 ml min(-1) 100 g(-1), respectively. BF, BV, and PS values of the tumor tissue of pancreatic adenocarcinoma decreased significantly compared to normal pancreas (P < 0.05).

CONCLUSIONS

Normal pancreas appears homogenous on perfusion CT. A significant decrease of BF, BV, and PS was observed in pancreatic adenocarcinoma. Dynamic 64-slice helical CT with perfusion imaging should be considered a potential modality to increase the accuracy of CT diagnosis for pancreatic adenocarcinoma.

Dynamic computed tomography of the pancreas in normal dogs and in a dog with pancreatic insulinoma

To establish optimal imaging conditions for enhanced computed tomography (CT) for canine pancreatic tumors, 10 healthy beagles were subjected to dynamic CT. This technique was then applied to a dog with suspected insulinoma. The changes in mean peak enhancement and the delay time of the aorta and pancreas were determined. In normal beagles, maximal arterial and pancreatic CT enhancement was observed at 15 +/- 2 s (795 +/- 52 Housfield unit [HU]) and 28 +/- 9 s (118 +/- 16HU) after contrast medium injection, respectively. Multiphase enhanced CT was performed in a pug with suspected insulinoma using the CT protocol defined for the normal beagles with some parameters modified; the images were acquired at the arterial (14 s after contrast medium injection), pancreatic (after 28 s), and equilibrium (after 90 s) phases; scanning was followed by exploratory laparotomy. CT images were characterized by an enhanced mass in the left pancreatic lobe at the arterial phase, during which the difference between the CT values of the mass and normal pancreas was the highest. Histopathologic diagnosis of the pancreatic mass was insulinoma. Thus, it appears that enhanced CT imaging can be used to delineate the pancreas from a pancreatic mass, and it may be helpful in deciding the need for surgery.