Radionuclide imaging of cardiac function represents a number of well-validated techniques for accurate determination of right (RV) and left ventricular (LV) ejection fraction (EF) and LV volumes. These first European guidelines give recommendations for how and when to use first-pass and equilibrium radionuclide ventriculography, gated myocardial perfusion scintigraphy, gated PET, and studies with non-imaging devices for the evaluation of cardiac function. The items covered are presented in 11 sections: clinical indications, radiopharmaceuticals and dosimetry, study acquisition, RV EF, LV EF, LV volumes, LV regional function, LV diastolic function, reports and image display and reference values from the literature of RVEF, LVEF and LV volumes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "prevailing or general consensus". The guidelines are designed to assist in the practice of referral to, performance, interpretation and reporting of nuclear cardiology studies for the evaluation of cardiac performance.
The authors used cine magnetic resonance (MR) velocity mapping to study flow in the superior vena cava (SVC) and inferior vena cava (IVC) of 13 healthy control subjects and 13 patients with right-sided cardiac disease. In the control subjects, peaks of flow in systole and diastole were observed, and mean SVC flow was 35% of the cardiac output. Respiratory gating was used in six control subjects to acquire images at end inspiration and end expiration, and although the systolic peak was reduced at end expiration, total flow was unchanged. A reduced systolic peak and retrograde flow in the IVC were observed in patients with tricuspid regurgitation. A reduced diastolic peak was seen in patients with pulmonary hypertension, pericardial constriction, and right ventricular dysplasia, reflecting reduced diastolic compliance of the right ventricle. In the patient with obstruction of the SVC, absence of flow was confirmed, and retrograde flow was seen in the azygos vein. The authors believe that cine MR velocity mapping is a reliable method of studying vena caval flow noninvasively and that it has important potential applications for the investigation of disorders of the right side of the heart.
Thirty-six patients were studied with magnetic resonance (MR) imaging 2-29 years after repair of coarctation of the aorta, and the findings were compared with clinical data and results of echocardiography, catheterization, angiography, and surgery. A satisfactory echocardiographic examination of the isthmus was achieved in 28 patients. Comparison with data from gradient measurements at catheterization and Doppler ultrasound shows that the reduction of lumen diameter correlates well with the gradient and that restenosis at the site of the repair can be suspected when the percentage of stenosis at the isthmus is greater than 50%. MR imaging showed a Dacron patch aneurysm in three patients. Cine MR imaging showed systolic signal loss in the ascending aorta that was presumed to be due, among other factors, to turbulent flow generated from a bicuspid valve. Similar signal loss was seen in the descending aorta distal to the site of the coarctation repair, but this was not related to the presence or absence of a gradient. Aortic compliance measured from transverse MR systolic and diastolic images was abnormally low, suggesting it may be a factor causing systolic hypertension after coarctation repair. MR imaging is a reliable and accurate noninvasive method likely to supersede other methods of assessing the aorta and isthmus following coarctation repair.
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