Myocardial signal intensity curves for myocardial perfusion studies may be made quantitative by the use of T1 measurements made after the first-pass of contrast agent. A short data acquisition method for T1 mapping is presented in which all data for each T1 map are acquired in a short breath hold, and the slice geometry and timing in the cardiac cycle exactly match that of the dynamic first-pass perfusion sequence. This allows accurate image registration of the T1 map with the first-pass series of images. The T1 method is based on varying the preparation-pulse delay time of a saturation recovery sequence, and in this implementation employs an ECG-triggered, single-shot, spoiled gradient echo technique with SENSE reconstruction. The method allows T1 estimates of three slices to be made in fifteen heartbeats. For a range of samples with T1 values equivalent to those found in the myocardium during the first-pass of contrast agent, T1 estimates were accurate to within 6%, and the variation between slices was 2% or less.
Magnetic resonance (MR) is well suited to imaging the pericardium. High resolution images synchronized with the cardiac cycle can be obtained in any plane. The wide field of view allows additional anatomical and functional information to be obtained from adjacent structures such as the aorta, pleura, lungs and mediastinum. MR is particularly useful in cases of pericardial constriction without an associated effusion, in patients with complex or loculated pericardial effusions and in pericardial tumours. In this article we illustrate the characteristic MR features of a variety of pericardial pathologies.
Balloon angioplasty was attempted, using hydrophillic Terumo guidewires, in 52 totally and subtotally occluded coronary arteries (50 patients), in which recanalisation by conventional angioplasty guidewires had failed. Hydrophillic guidewires had a crossing success rate of 65.4% (34/52); there was subsequently a technical success rate of 56% (29/52) and clinical success of 39% (20/52). Dissection of the coronary artery was seen in 16/29 technically successful cases. In 12/16 arteries, dissection was small and localised, whereas in 4/16 large and extended distally. There was one myocardial infarction and no peri-procedural deaths. Eleven out of 29 technically successful cases continued to be regarded as successful 12 mo postangioplasty. We conclude that the hydrophillic Terumo guidewire can improve the success rate in angioplasty of totally and subtotally occluded coronary arteries when conventional wires have failed.
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