Volume Histogram Analysis for Lung Thin-Section Computed Tomography: Differentiation Between Usual Interstitial Pneumonia and Nonspecific Interstitial Pneumoni

Objective: The aim of this study was to evaluate volume histogram analysis between usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP). Methods: Sixty cases (UIP, n = 22; NSIP, n = 38) were evaluated retrospectively. Three parameters (contrast, variance, and entropy) were calculated in 3 types of regions of interest (ROIs): (a) whole lung, (b) right lower lobe, and (c) cubic ROIs. To evaluate the influence of extent of abnormal findings, the numbers of voxels with low or high density in whole lung were compared with the 3 parameters. Result: No significant differences were observed between the ROIs of whole lung and the right lower lobe. In all cubic ROIs, entropy in UIP was larger than that in NSIP (P < 0.001). The numbers of voxels with low-density areas significantly correlated with the values of contrast and entropy, whereas those with high-density areas significantly correlated with all 3 parameters. Conclusion: Volume histogram analysis for cubic ROIs may be feasible for differentiating between UIP and NSIP.