Clinical application of subtraction CT imaging for evaluation of pulmonary vascular permeability

In this clinical study, one normal subject, one patient with primary interstitial pneumonia, one patient with segmental pneumonia due to Staphylococcus aureus, one patient with post-operative esophageal carcinoma, and two patients with mitral stenosis were studied. Dynamic CT scan images under continuous injection of low osmotic contrast medium were analyzed in series, in an attempt to evaluate vascular permeability quantitatively. The following results were obtained: 1) Subtraction CT scan image 10 minutes after the start of contrast medium injection in two patients with pneumonia, showed a reduction of pulmonary vascular permeability following therapy. 2) Subtraction CT scan image of the patient with post-operative esophageal carcinoma treated with 25 Gy radiation showed a discrepancy between pulmonary vascular permeability and other findings. 3) In hemodynamically stable patients with mitral stenosis, subtraction CT images demonstrated that pulmonary vascular permeability was not affected by pulmonary congestion, irrespective of its severity.