Usefulness of coronal reformations in the diagnostic evaluation of infiltrative lung disease.

PURPOSE

To evaluate the diagnostic accuracy of coronal thin sections as an alternative to transverse high-resolution computed tomography (HRCT) scans in the diagnostic approach to infiltrative lung disease (ILD) with multislice computed tomography (MSCT).

MATERIALS AND METHODS

Fifty consecutive patients referred for suspicion of ILD underwent MSCT (collimation: 4 mm x 1 mm; pitch: 1.75; scan time: 0.5 seconds; 80 mA per slice) of the entire thorax. Two sets of lung images were systematically reconstructed: 1-mm thick transverse computed tomography (CT) scans (i.e., HRCT scans) (group 1) and 1-mm thick coronal images (group 2). Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial frequency algorithm. Two observers independently analyzed the overall image quality, the presence and distribution of CT features of ILD, and the diagnostic value of group 1 and group 2 lung images.

RESULTS

Group 1 and group 2 images were coded as interpretable, with minimal respiratory artifacts in the lower lung zones in two cases (4%). Presence of abnormal lung infiltration was found in 38 patients in group 2 with concordant interpretation of group 1 images. No significant difference was found in the identification of CT features of ILD between group 2 and group 1 (nodules: 32% vs. 30%; lines: 14% vs. 16%; increased attenuation: 24% vs. 26%; fibrosis: 48% vs. 50%; distortion: 46% vs. 50%; and abnormal interfaces: 16% in both groups). Distribution of lung abnormalities in central, peripheral, anterior, and/or posterior lung zones was similarly recognized in group 2 and group 1. In patients with extensive lung infiltration, the vertical predominance of lung changes was more precisely assessed in group 2 (n = 12) than in group 1 (n = 4). For a mean coverage of 260 mm in this study group, the mean number of sections to be interpreted was significantly lower in group 2 (19 sections) than in group 1 (28 sections) (P < 0.01).

CONCLUSION

Coronal sections allow a diagnostic approach to ILD as precise as that provided with HRCT scans, based on the interpretation of a significantly reduced number of images.