Usefulness of Coronal Reformations in the Diagnostic Evaluation of Infiltrative Lung Disease

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Abstract
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). 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. 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). 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.