Three-dimensional Computed Tomography Image of Small Pulmonary Lesions

To evaluate diagnostic imaging of small lesions in the peripherallung, three-dimensional (3D) reconstruction CT images were usedto study 36 cases (including which had been 19 resected) ofpulmonary nodules > 3 cm in diameter. Rapid scanning wasemployed in 17 cases and helical scanning (in which the X-raytube rotates continuously with simultaneous table sliding) in19 cases. The rapid scanning could not be evaluated in two casesbecause respiratory motion resulted in discontinuous image data.We were able to evaluate 34 cases. The addition of 3D imagesto the conventional iamges made it possible for us to obtainuseful information on visualizing relations between nodulesand vascular structures in 32% (11/34) of the cases. The 3Dimages enabled us to visualize the lesions and pulmonary vesselsthree-dimensionally. It was, however, difficult to evaluatelesion shape since we were able to obtain useful informationin only 3% (1/34) of the cases. In helical scanning, data areacquired from an extensive area within a short time, providingconsecutive axial-slice images remain free of any respiratoryartifacts. In this regard, helical scanning is suitable forgenerating 3D images. A diagnostic procedure based on 3D lesionanalysis should be developed and standardized.