Shape preserving three-dimensional display of myocardial scintigraphic data.

A three-dimensional display has been developed which is specifically suited to the visualization of myocardial single photon emission tomographic (SPET) data. A set of radial maxima voxels, representative of the whole left ventricle uptake and shape is first extracted by cylindrical and spherical sampling of the short axis slices. A three-dimensional representation of these voxels is then obtained, with hues depicting the uptake amount and shades (i.e. intensity and saturation) depicting the shape. This technique is suitable for 201Tl and 99TCm-hexakis-2-methoxyisobutyl isonitrile (99TCm-sestamibi) myocardial images. It is proposed as an aid to interpreting myocardial SPET as it enables the physician to distinguish simultaneously the actual shape, the extent and the severity of perfusion defects on a single frame.

Quantitative comparison of prone and supine myocardial SPECT MIBI images.

The myocardial count distribution and the stress/rest ratio distribution were compared between prone and supine Tc-99m MIBI myocardial SPECT acquisitions. Ninety-nine male patients with a low stress supine inferior wall count underwent stress and rest acquisitions in the supine and prone positions successively. For each study, values depicting the inferior, anterior, septal, and lateral wall counts were extracted from a medioventricular normalized circumferential profile and underwent a statistical analysis (Student's paired t-test). On prone imaging, when compared to supine imaging, counts showed a highly significant mean relative increase of 11% +/- 1% in the inferior wall and of 7% +/- 1% in the septum. Conversely, these counts showed a significant mean relative decrease of 4% +/- 1% in the anterior wall and of 3% +/- 1% in the lateral wall. Moreover, the inferior wall stress/rest ratio showed a highly significant mean relative increase (6% +/- 2%). The prone position is probably preferable for interpreting the inferior wall and septum, where relative counts are enhanced, as with TI-201, and because the inferior stress-rest discrepancies are reduced in that position. But the anterior and lateral wall information is impaired in the prone position. The authors suggest, in case of a low stress supine inferior count, the combination of both positions, which is feasible with Tc-99m MIBI, in order to prevent a misleading interpretation.

[Quantification of chronic aortic insufficiency. Comparison between Doppler ultrasonic diagnosis and the radiocardiogram]. / Quantification de l'insuffisance aortique chronique. Comparaison de l'échographie Doppler et du radiocardiogramme.

The objective of this study is to quantify aortic insufficiency by comparing pulsated Doppler ultrasonography and radiocardiography used as reference test. Since february 1986, 23 patients were tested with both techniques within 15 days. The Doppler ultrasonography enabled to quantify aortic insufficiency in 4 stages by semi-quantitative mapping of the regurgitation flow of the left ventricle (LV). Radiocardiography (RCG) has enabled the determination of the regurgitation fraction (RF), for each patient. A mean RF was calculated on RCG, for each Doppler stage. The FR difference between each Doppler stage is significant, especially between minimal and severe aortic insufficiency. RCG is the first stage of an isotopic examination, at rest and during stress; it may be followed by Doppler ultrasonography in monitoring patients with aortic insufficiency.