[Digital perfusion images for evaluating patients with mitral valve replacement].

To determine whether the distribution of pulmonary perfusion can be applied as a noninvasive means of evaluating patients with mitral valve replacement (MVR), computerized Tc-99m MAA pulmonary perfusion images (digital perfusion images: DPI) were obtained for 32 patients in the preoperative, early postoperative and late postoperative (18 months mean) periods. DPI consisted of isocount areas, and a 100-70% area was defined as a hyperperfusion area. The distribution of pulmonary perfusion was evaluated using patterns of hyperperfusion area in anterior DPI. In 32 patients above-mentioned had the hyperperfusion areas in the upper lung fields preoperatively, the perfusion of the lung base was investigated. In 21 patients hyperperfusion area appeared in the lung base in the late follow-up period (group A), and all patients improved clinically. In 11 patients, the DPI improved to nearly normal patterns. In five patients, the DPI improved after one year postoperatively. In 11 patients, hyperperfusion areas did not appear in the lung base in the late follow-up period (group B). Six of the 11 patients did not improve clinically. There were no significant hemodynamic differences between groups A and B except for slight differences in the postoperative pulmonary vascular resistance. These results suggested significant correlations between the clinical improvement and the normalization of the DPI. The use of DPI patterns may facilitate quantitative and objective estimations of postoperative states. Since DPI are easy to perform noninvasively, DPI may comprise a useful graphic diagnostic method for evaluating patients with MVR.