Evaluation of SPECT imaging capability in various lung diseases

Clinical study on segmental disorders in various pulmonary diseases was performed using Tc-99m MAA, Kr-81m; and evaluation of single photon emission computed tomography (SPECT) is reported in this paper. As a fundamental study, plastic segmental lung phantom was made, and filled with Tc-99m O4- solution to study the SPECT imaging capability. From right S1 to left S10 defect and all lobar defects of the lung phantoms were studied in turn by SPECT, which obtained three dimensional images for each portion of the segmental defect. The imaging capability of SPECT was compared with the planar image in each defective portion of the segmental phantom. Absolute superiority of SPECT images to planar images was shown on right S7, S8, left Ssub(7+8) and S9 defective portions. The superiority of SPECT also was shown on some other defective portions of the segmental phantoms. As a clinical study, in seven cases of aortitis syndrome, the roentgenograms and X-CT images did not show any significant abnormal signs. SPECT perfusion images showed some visible abnormalities in six of the cases. In detectability of abnormal findings in pulmonary diseases, there were some indications of the superiority of lung scintigraphy, compared with the roentgenograms and X-CT images, especially in aortitis syndrome that may have mainly functional damage without significant organic changes. The SPECT images were only 3--6% superior to the planar images in detecting abnormalities. However, after careful study of defective portions of the segmental phantoms, it was easier to determine the location and the level of functional disorders using SPECT images. (author)