Volume-Controlled Histographic Analysis of Pulmonary Parenchyma in Normal and Diffuse Parenchymal Lung Disease: A Pilot Study

PURPOSE: To evaluate the clinical usefulness of a home-made histographic analysis system using a lung volume controller. MATERIALS AND METHODS:Our study involved ten healthy volunteers, ten emphysema patients, and two idio-pathic pulmonary fibrosis (IPF) patients. Using a home-made lung volume controller, images were obtained in the upper, middle, and lower lung zones at 70%, 50%, and 20% of vital capacity. Electron beam tomography was used and scanning parameters were single slice mode, 10-mm slice thickness, 0.4-second scan time, and 35 -cm field of view. Using a home-made semi-automated program, pulmonary parenchyma was isolated and a histogram then obtained. Seven histographic parameters, namely mean density (MD), density at maximal frequency (DMF), maximal ascending gradient (MAG), maximal ascending gradient density (MAGD), maxi-mal descending gradient (MDG), maximal descending gradient density (MDGD), and full width at half maxi-mum (FWHM) were derived from the histogram. We compared normal controls with abnormal groups includ-ing emphysema and IPF patients at the same respiration levels. RESULTS: A normal histographic zone with +/-1 standard deviation was obtained. Histographic curves of normal controls shifted toward the high density level, and the width of the normal zone increased as the level of inspi-ration decreased. In ten normal controls, MD, DMF, MAG, MAGD, MDG, MDGD, and FWHM readings at a 70% inspiration level were lower than those at 20% (p<0.05). At the same level of inspiration, histograms of emphysema patients were located at a lower density area than those of normal controls. As inspiration status decreased, histograms of emphysema patients showed diminished shift compared with those of normal con-trols. At 50% and 20% inspiration levels, the MD, DMF, and MAGD readings of emphysema patients were significantly lower than those of normal controls (p<0.05). Compared with those of normal controls, his-tograms of the two IPF patients obtained at three inspiration levels were located in an area of higher density. CONCLUSION: Using a home-made histographic analysis system which included a lung volume controller, pa-tients with diffuse parenchymal lung disease could be distinguished from normal controls. The method may be useful for the diagnosis and follow up of diffuse parenchymal lung diseases.

The Calculation of the Electroretinographic Power

To promote the electrophysiologic diagnostic efficiency, the program for calculation of the total power in the frequency domain and of the area in the time domain of the electroretinogram was designed. The total power is calculated by integration of the squared power spectrum obtained by Fourier transform (Parseval theorem) in the time domain. The dominant power is the power of the dominant frequency in power spectrum and is calculated by integration of the squared peak area spectrum. The sectional inegration of the squared power spectrum can be established by manual input. The inplemented software also has the functions that calculate the summed amplitud and area of the oscillatory potentials in the time domain. And it performs each functions by selection of pop-up menu with mouse to use conveniently under graphic interface, compatible with UTAS-E2000 system.