DIFFUSE LUNG-DISEASE - ASSESSMENT WITH HELICAL CT - PRELIMINARY-OBSERVATIONS OF THE ROLE OF MAXIMUM AND MINIMUM INTENSITY PROJECTION IMAGES

PURPOSE: To evaluate assessment of diffuse lung disease with helical c omputed tomography (CT) and maximum intensity projection (MIP) and min imum intensity projection images. MATERIALS AND METHODS: Six patients with suspected lung disease (the control group) and 20 patients with d ocumented disease underwent axial helical CT through the upper and low er lung fields. Findings on the MIP and minimum intensity projection i mages of each helical data set were compared with findings on the thin -section scan obtained at the midplane of the series. RESULTS: Owing t o markedly improved visualization of peripheral pulmonary vessels (n = 26) and improved spatial orientation, MIP images were superior to hel ical scans to help identify pulmonary nodules and characterize them as peribronchovascular (n = 2) or centrilobular (n = 7). Minimum intensi ty projection images were more accurate than thin-section scans to hel p identify lumina of central airways (n = 23) and define abnormal low (n = 15) and high (ground-glass) (n = 8) lung attenuation. Conventiona l thin-section scans depicted fine linear structures more clearly than either MIP or minimum intensity projection images, including the wall s of peripheral, dilated airways (n = 3) and interlobular septa (n = 3 ). MIP and minimum intensity projection images added additional diagno stic findings to those on thin-section scans in 13 (65%) of 20 cases. CONCLUSION: MIP and minimum intensity projection images of helical dat a sets may help diagnosis of a wide spectrum of diffuse lung diseases.