[Multiphasic contrast-enhanced CT: correlation of the peak attenuation in the aorta abdominalis and portal vein with easily detectable clinical parameters]

OBJECTIVE

The diagnostic value of a multiphase CT strongly depends on the correct timepoints of analysis. Therefore, we investigated whether the peak attenuation time in the aorta and portal vein are predictable using easily detectable clinical parameters. Regression equations were developed that enable an approximate prediction of these scan times.

MATERIAL AND METHODS

Contrast dynamic CT was performed in 39 anaesthetised dogs of different breeds. The heart rate at the onset of the examination, the age and the body weight were documented. The contrast agent Imeron 300® was injected into a cephalic vein at 3 ml/s with 600 mg iodine/kg body weight using an automatic injector and a dynamic axial CT was started at the same time. The peak enhancement time in the aorta (pETA) and portal vein (pETP) were measured.

RESULTS

The mean pETA was 24.5 ± 8.6 seconds and the mean pETP was 43.6 ± 13.4 seconds. There was a strong correlation (r = 0.92) between pETA and body weight in combination with the heart rate, and a moderate correlation (r = 0.66) between pETP and body weight in combination with the age. The regression equation was: pETA = 12.23 + 0.61 body weight - 0.07 heart rate. The time between pETA and pETP was 8-24 seconds in 34 animals.

CONCLUSION

To plan the arterial peak the authors recommend the use of the established regression equations based on the statistical results or alternatively bolus tracking to plan the arterial peak. When it is planned to examine the portal venous peak, an interscan duration of 8-14 seconds is recommended.

Feline distal aortic thromboembolism: a review of 44 cases (1990-1998)

The clinical case records of 44 cats with distal aortic thromboembolism were reviewed. These detailed 49 separate episodes of thromboembolism. Of the 44 cats, 33 (75%) were neutered males, and 43 (98%) were domestic shorthairs. The mean age was 8.7 years (age range 2-16 years). Evidence of pre-existing heart disease had been noted in 23% of cases. Heart failure was a concurrent diagnosis in 51% of episodes and 36% of these cases survived their thromboembolic episodes. Overall, cats survived 39% of the episodes. Cats died during 28% of the episodes, while 33% of the episodes resulted in the cats being euthanased. The median survival time was 6 months. Seventeen per cent of cats on prophylactic aspirin therapy experienced an episode of re-embolisation. Forty-three per cent of episodes occurred in the spring.

Radiographic diagnosis of calcific aortic arteriosclerosis in a Jersey cow

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A retrospective study of 100 cases of feline distal aortic thromboembolism: 1977-1993

The medical records of 100 cats with distal aortic thromboembolism were reviewed. The average age was 7.7 years, with the neutered male being the most common signalment (63%). Evidence of preexisting cardiac disease was noted in 11% of the cases. A murmur or arrhythmia was noted in 57% of the cases on presentation. Frequent laboratory abnormalities included elevations in blood glucose, alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, and creatinine. Radiographic and electrocardiographic abnormalities were common (89% and 85%, respectively). The most frequent, underlying disease was hypertrophic feline cardiomyopathy (58%), with the left atrial size (as measured by M-mode) significantly increased in the majority of cases (mean left atrial-to-aortic ratio, 2.08). The average, long-term survival in the 37% of cases which survived the initial thromboembolic episode was 11.5 months. The remaining cases either died (28%) or were euthanized (35%).

Pulmonary arteriography and hemodynamics during feline heartworm disease. Effect of aspirin

The ability of aspirin to block arterial disease and thromboembolism of the pulmonary arteries was studied in heartworm-infected cats. Three groups of cats were transplanted with four heartworms per cat and studied. One group of eight cats (aspirin group) received aspirin (97.5 mg, twice a week) for the five-month infection and another group of eight cats served as the nontreated control group (nontreated group). Based upon the results of the first two groups, the third group (adjusted aspirin group) of six cats was studied in which the aspirin dosage was adjusted in order to maintain an inhibition of in vitro platelet aggregation. Cats were studied by nonselective pulmonary arteriograms before heartworm transplantation and by selective arteriograms, aortograms, and pulmonary hemodynamics five months after heartworm transplant. Pulmonary hypertension, (mean pulmonary artery pressures greater than 16 mmHg), was discovered in three cats with one cat in each group. There were no differences in the mean pulmonary artery pressure or vascular resistance between the groups. Many of the arterial diameters for the nontreated and aspirin groups were greater after the five-month infection than before heartworm infection. All of the postinfection caudal arteries were tortuous and had aneurysms. Some of the caudal lung lobes had perfused areas that appeared to have a hypervascular microvasculature. The proportion of obstructed right and left distal caudal pulmonary arteries and the resulting nonperfused area of the caudal lung lobe in the nontreated and aspirin treated groups were each greater than in the adjusted aspirin group.(ABSTRACT TRUNCATED AT 250 WORDS)