Transsplenic portal scintigraphy using 99mTc-pertechnetate for the diagnosis of portosystemic shunts in cats: a retrospective review of 12 patients.

Portosystemic shunts (PSS), congenital or acquired, occur uncommonly in the feline population. The diagnostic approach is similar to one in dogs suspected of a PSS based on the clinical signs and haematological and biochemical changes. Diagnostic imaging, however, is key for the confirmation of a PSS. Although abdominal ultrasound is the first-choice diagnostic imaging modality, the results are not always unequivocal. Transsplenic portal scintigraphy (TSPS) using (99m)Tc-pertechnetate is a well-established technique in canine medicine, providing relatively fast and easy confirmation of the presence or absence of a PSS. As the prevalence of PSS is much lower in the feline population, this technique has not been widely used in cats. This retrospective study of 12 cases gives an overview of the potential of TSPS in the diagnostic work-up of PSS in cats (2005-2012).

Comparison of echocardiography and gated equilibrium radionuclide ventriculography in the measurements of left ventricular systolic function parameters in healthy dogs.

Left ventricular systolic function was assessed in 12 healthy dogs with equilibrium radionuclide ventriculography. The results of the analysis were compared to traditional echocardiographic measurements. Left ventricular internal dimensions and volume were measured at the time of end-systole and end-diastole. Ejection fraction--one of the most informative parameters of cardiac function--was calculated in each animal. Values (e.g. EDD, ESD, EDV, ESV) measured by the scintigraphic method were significantly (Student's t-test, p < 0.05) higher than the data obtained by echocardiography. Ejection fraction (EF) was the only parameter that did not differ significantly when comparing the two imaging techniques. The difference between the results of parallel measurements was in inverse ratio to the size of the heart.

The use of gated radionuclide ventriculography as a noninvasive method of evaluating right ventricular function in dogs with experimentally induced congestive heart failure.

Gated radionuclide ventriculography was evaluated as a noninvasive method of quantifying right ventricular function in dogs with experimentally induced congestive heart failure. Gated radionuclide ventriculography measurements of right ventricular function (right ventricular ejection fraction, right ventricular average emptying rate, and right ventricular average filling rate) were related to standard hemodynamic and echocardiographic measurements. Congestive heart failure was induced by rapid ventricular pacing in eight normal dogs. Hemodynamic, echocardiographic, and gated radionuclide ventriculography measurements were obtained before and after development of biventricular failure. Congestive heart failure resulted in significant changes in all hemodynamic, echocardiographic, and gated radionuclide ventriculography measurements with the exception of systemic arterial pressure. Right ventricular ejection fraction was inversely related to pulmonary artery systolic, diastolic, and mean pressure, and right ventricular average emptying rate was inversely related to the pulmonary artery systolic, diastolic, and mean pressure. Right ventricular ejection fraction was inversely related to left ventricular filling pressure, (pulmonary capillary wedge pressure). Neither the echocardiographic measurements of right ventricular size (right ventricular internal diastolic dimension) nor the right ventricular end-diastolic pressure were related to right ventricular ejection fraction and right ventricular average emptying rate. However, echocardiographic measurements of right ventricular dimension were related to right ventricular filling pressure. The gated radionuclide ventriculography indexes of right ventricular function, right ventricular ejection fraction and right ventricular average emptying rate, are affected by afterload but unaffected by preload, whereas the echocardiographic measurement of right ventricular dimension is related to preload. Gated radionuclide ventriculography provides right ventricular data which is unique from that obtained by standard echocardiographic imaging. Also, gated radionuclide ventriculography has potential value as a noninvasive means of estimating a change in pulmonary artery pressure.

Non-invasive evaluation of the cardiac function in golden retriever dogs by radionuclide angiography.

Golden Retriever dogs manifest an X-linked, Duchenne-like, muscular dystrophy with a characteristic lack of dystrophin. Histologic findings have demonstrated the cardiac involvement in these dogs to be a model for the cardiac insufficiency in human Duchenne muscular dystrophy (DMD). The goal of this study was to assess the capability of radionuclide angiography (RNA) as an assessment tool to measure the ventricular dysfunction in these dogs. Three dogs, one normal and two with muscular dystrophy (MD), were studied by equilibrium gated blood pool. Red blood cells were labelled with 420 MBq of 99mTc. The three dogs lying on their left sides on the table, received no drugs and were not restrained in any manner. RNA left ejection fraction (EF) and echographic measurements of left ventricular fractional shortening (FS) were performed during the same session. EF values were 61%, 48%, 36% and FS values were 47%, 32%, 26%, respectively, for the control dog, the 6 month old MD dog and the 12 month old MD dog. This preliminary study demonstrates the potential usefulness of RNA for the non-invasive follow-up exams of specific therapy in a canine model of muscular dystrophy.

Radionuclide angiocardiography in the normal dog: equilibrium studies.

Equilibrium radionuclide ventriculography was applied in 27 healthy anaesthetised dogs (9 to 60 kg) after labelling the blood pool with 99mTc, using a gamma camera with a computer on-line. Quantitative analysis of the calibrated ventriculogram provided the following left ventricular parameters: the end diastolic volume (EDV), the ejection fraction (EF), the possible degree of regurgitation and as velocity indices the peak ejection and peak refilling rates (PER and PRR). Averaged results were: EDV 1.8 ml kg-1; EF 0.59; PER 4.3 EDV s-1; PRR 3.75 EDV s-1. Visual inspection of the camera images may reveal abnormal wall motions and dilatation of heart chambers.

Comparison of left ventricular ejection fractions determined in healthy anesthetized dogs by echocardiography and gated equilibrium radionuclide ventriculography.

Left ventricular ejection fractions (LVEF) of 8 pentobarbital-anesthetized dogs were calculated by gated equilibrium radionuclide ventriculography (RVG) and by M-mode and two-dimensional echocardiography (2-DE) prior to and during constant IV infusion of isoproterenol. Mean LVEF (+/- SD), determined with RVG by use of an automatic edge detection algorithm (RVG-auto) to define the left ventricular region of interest, increased from a resting value of 53.5% (+/- 4.9%) to 71.9% (+/- 6.8%) during isoproterenol infusion. Mean LVEF, determined with RVG by use of visual inspection (RVG-manual) to define the left ventricular region of interest increased from a resting value of 51.6% +/- 3.8% to 67.0% +/- 5.6% during isoproterenol infusion. Using 2-DE and the bullet formula to calculate left ventricular volume (LVV = 5/6 x cross-sectional area x length), mean LVEF increased from 52.3% (+/- 3.50) to 74.7% (+/- 5.0%). Using 2-DE area measurements and Teicholz formula, mean LVEF increased from 48.9% (+/- 5.1%) to 69.5% (+/- 6.0%). Using M-mode echocardiographic left ventricular diameter measurements and Teicholz formula, mean LVEF increased from 52.3 (+/- 9.0%) to 78.3% (+/- 8.1%). Before and during isoproterenol infusion, the mean LVEF values calculated by RVG agreed closely with mean LVEF values calculated from M-mode and 2-DE. Correlation coefficients determined from linear regression analysis of LVEF by echocardiography vs LVEF by radionuclide ventriculography ranged from 0.79 to 0.88. Correlation coefficients were higher and SEM were lower when LVEF was determined by RVG-manual, rather than by RVG-auto methods and when LVEF was calculated from 2-DE measurements, rather than from M-mode measurements.