PubMed · 538342
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K Miyazawa. 1979. [Exercise test and heart function].. https://pubmed.ncbi.nlm.nih.gov/538342/
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Use of the personal microcomputer for the analysis of clinical cardial PET studies acquired at the Paul Scherrer Institute in Villigen, Switzerland. At present this is the only PET facility in Switzerland. As the local computers were not usually available for image analysis, it was necessary to find a convenient way to visualize and analyze the PET images in our department in the Cantonal Hospital, Aarau (distance to Villigen some 30 km). The personal microcomputer is, as other authors have already shown, in fact capable of handling the acquired images (128 by 128 pixels) easily. We use a Macintosh IIcx (16 MHz Motorola 68030 CPU) as image analysis workstation. In spring 1990 we implemented a software which could read the original Siemens matrix file directly into the Macintosh PC. As the handling of this software was somewhat clumsy, we now use a very powerful software ("Explorer", UCLA), which is specially designed for PET analysis. Analysis of PET data on the personal computer saves both time and money as we are able to use a standard PC periphery, which is less expensive than specially designed medical units.
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A magnetic resonance imaging (MRI) method is presented to detect, localize, and quantify myocardial kinematics by measuring the material rate-of-strain tensor at each pixel in gated NMR images of the heart. The immediate, local effect of muscular activity is self-deformation, and the strain tensor is the basic mathematical device by which such deformation may be quantified. The present method, called "strain-phase" MRI (SP-MRI), entails four steps: (1) the velocity of the myocardium is encoded by means of a set of motion-sensitive NMR image acquisitions, one image per velocity component; (2) the spatial derivatives of the velocity are computed at each pixel; (3) the velocity-derivative data are combined to compute an approximation of the strain-rate tensor of the myocardium at each pixel; and (4) the strain-rate tensor data are simplified to produce a color-coded functional image which represents strain-rate components which are of particular biomedical interest in the myocardium. We present a quantitative SP-MRI methodology suited to conventional MRI, and in addition present an "echo-planar" methodology, able to produce qualitative functional images of myocardial kinematics at almost real-time speeds. Two-dimensional strain-phase MRI data acquired in normal human subjects are presented. These data demonstrate the practicability of SP-MRI in vivo, that SP-MRI resolves myocardial kinematics at the single-pixel scale, having resolution comparable to that of conventional MRI, and that SP-MRI data may have a signal-to-noise ratio up to 50% as great as that of the conventional MRI data from which they are produced. SP-MRI measurements of the local instantaneous strain rates in the human left ventricular myocardium are quantitatively consistent with known transmural average values of myocardial strain.