[en] The effect of bromhexine on mucociliary clearance mechanisms was evaluated in 10 patients with various chest diseases in stable condition by radioaerosol inhalation lung scintigraphy. Visual and numerical evaluations were made by radioaerosol inhalation lung cine-scintigraphy and by calculating the following 5 indices; i) lung retention ratio, ii) airway deposition ratio, iii) airway retention ratio, iv) airway clearance efficiency and v) alveolar deposition ratio, respectively. Lung function tests and chest roentgenograms were also performed before and after administration of bromhexine. Aerosol inhalation lung cine-scintigraphy did not reveal a very marked difference in mucus transport patterns on the trachea after administration of bromhexine, but numerical analysis showed significantly smaller lung and airway retention ratios and greater airway clearance efficiencies, whereas airway deposition ratios remained unchanged in the first 80 min, indicating a more efficient airway mucus clearance after bromhexine administration. (author)

[en] The purpose of this study was to assess the effect of back-ground countrate (BGC) on the ventilation index (VI)'s and establish areasonable and simple way to correct the BGC. Xe-133 gas was inhaled with a semi-equilibrium method and washed out with air. Three ROI's were made for BGC correction; an entire chest (ROI 1), an area covering Xe-133 activity within lungs and its scatter (ROI 2), and an area over the lung alone (ROI 3). Firstly we estimated the BGC per matrix in the region between ROI 1 and ROI 2 in each frame data. By analyzing the washout curves on the whole lung region (ROI 3) and regional lungs between semi-equilibrium and 120 seconds after washout started, three different VI's were calculated; real half time (T sub(1/2R)), half time estimated from exponential curve fitting (T sub(1/2exp)), and/or the area under the curve (A) divided by the difference in mean count rate during semiequilibrium (a) and at 120 second (c) after washout started (T sub((A/H)) = A/(a-c)). True VI's were calculated after BGC correction in each frame data. There was no uniform correlation between the non-corrected VI's and true ones, respectively. Therefore, we had to correct BGC to calculate each of the three VI's exactly. There were statistically significant correlations between 'turn-over rate' (= V radical sub(E) min/(FRC + V sub(T)) and any of the true VI's calculated from the overall lung area (r = -0.8). T sub(1/2R) could hardly be estimated in regional lungs in patients with chronic obstructive lung disease. T sub ((A/H)) correlated better with T sub(1/2R) (r = 0.941) than T sub(1/2exp). T sub((A/H)) calculated after BGC correction in 'A', 'a', and 'c' were equal to T sub((A/H) calculated after BGC correction on each frame. In conclusion, the best VI is T sub((A/H)) calculated after BGC correction on 'A', 'a', and 'c'. (J.P.N.)

[en] In order to get a functional image of the lungs for estimating regional ventilation, the ¹³³Xe ventilation studies by a single breath washin and washout with air were analyzed on 39 patients with various chest diseases and 4 normal subjects. We analyzed the washout curves on the whole and regional lungs between 10 and 75 or between 10 and 130 sec after washout started. Three different ventilation indexes were calculated; real half time (T 1/2 R), half time estimated from exponential curve-fitting(1/2 T exp), and/or the area under the washout curve divided by the difference in mean count-rate between 10 and 75 or between 10 and 130 sec after washout started (T sub(A,H)). When a single matrix was selected out of 32x32 matrixes as a region of interest in the lung, the washout curve fluctuated so much that it was difficult to get the regional T 1/2 R. In patients with good lung function and/or in the normal subjects, T 1/2 R could be estimated without difficulty even in a lung region larger than or equal to the size of a single matrix when the lungs were divided into 16x16 matrixes, but in patients with COPD it could still hardly be estimated. In a single matrix out of 16x16 matrixes the correlation between T 1/2 R and T sub(A,H) become higher and the correlation between T 1/2 R and T 1/2 exp was less good as we made the interval of analysis longer. T sub(A,H) correlated better with T 1/2 R than T 1/2 exp in any interval of analysis. There was a statistically significant correlation between FEVsub(1.0)% and each of the three indexes calculated from overall lung area (r=0.8). To make a functional image of regional ventilation by ¹³³Xe single breath washin and washout procedure, it would be better to use the following: a) interval of analysis between 10 and 130 sec after washout started; b) 16x16 matrix; and c) T sub(A,H) as a ventilation index. (author)

[en] Physical parameters influencing deposition patterns of inhaled aerosol in the lungs are the size distribution of inhaled aerosol and the carrier gas which transports aerosol into the lungs. We measured median diameter (d sub(m)) of ultrasonically generated aerosol in terms of radioactivity (weight) and its geometric standard deviation (σsub(g)) by using a cascade impactor under the following three different clinically simulated conditions; 1) without a reservoir in place between the aerosol generator and a mouth piece, and with air as a carrier gas, 2) with a reservoir, and with air as a carrier gas and 3) with a reservoir, and with a mixture of 80% helium (He) and 20% oxygen (O₂) as a carrier gas. Median diameters and geometric standard deviations were 4.18 micron and 1.76, 3.73 micron and 1.73 and 2.76 micron and 1.82, respectively. Inhaled aerosol generated without a reservoir and with air as a carrier gas tanded to deposit on the major airways, revealing the so-called ''central pattern''-like deposition patterns, and was considered to be useful for the study of mucociliary clearance mechanism in the lungs, whereas that generated with a reservoir in place, and with a mixture of 80% He and 20% O₂ as a carrier gas deposited most evenly in the lung periphery, and it was suited to the study of ventilation in the lungs. Aerosol generated with a reservoir in place and with air as a carrier gas, however, showed more or less an in-between deposition pattern and was suited to use in the routine clinical aerosol inhalation lung imaging. (author)

[en] A new modality of display following radioaerosol inhalation which we call ''radioaerosol inhalation lung cine-scintigraphy'' or ''aerosol inhalation cine-scintigraphy'' in short has enabled us to visualize the movement of inhaled radioactivity after its deposition in the lungs and allowed us to assess mucociliary clearance mechanism more directly and accurately than by any other means as far described. Mucociliary clearance is usually cephalad in direction from peripherally to proximally, but pathologic conditions such as pulmonary emphysema or bronchogenic carcinoma could not only retard or stop the clearance but also drive radioactivity transported from one lung into the opposite side or even retrogress the mucus flow. Radioaerosol inhalation lung cine-scintigraphy has also helped to select the regions of interest to get regional clearance curves and to interpret the meaning of each clearance curve thus obtained. This new modality is expected to serve as an indispensable means to study mucociliary clearance mechanism, a potentially important non-respiratory function of the lungs. (author)

[en] Three types of aerosol nebulizers used in clinical practice, a jet type (JT), and IPPB (Bennett PR-2) and an ultrasonic nebulizer (Mistogen EN 142) (US) were studied regarding aerosol size distribution, efficiency in aerosol output, efficiency in lung deposition and deposition patterns in the lungs. The JT was operated both manually and mechanically. Tc-99m-albumin solution was the agent for aerosol generation. Aerosol size was measured by a cascade impactor, efficiency by measuring radioactivity in the lungs and nebulizers and deposition patterns by visual comparison. Mass median diameter (MMD) was the largest (4.18 μ) with its geometric standard deviation of 1.76 with the US, and the other nebulizers showed smaller MMD (2.00 - 2.35 μ) and broader geometric standard deviations. Aerosol output was 4 times more efficient with the US than with the others. Lung deposition was 8 times more efficient with the US, 7 times with the mechanically operated JT, and 6 times with the IPPB than the manually operated JT. Overall aerosol deposition in the lungs was the most efficient with the US, but the IPPB showed better penetration in normal subjects and patients with the least obstructive disturbance. Manually operated JT tended to produce the so-called central deposition pattern even in normal subjects. In conclusion, of the three nebulizers tested, the MMD of aerosol generated was the largest with the US, and the US was the most efficient in aerosol output and lung deposition. (author)

[en] Uneven distribution of inhaled aerosol in the lungs is the characteristics of obstructive airways disease such as chronic bronchitis and pulmonary emphysema, and has been classified typically into peripheral and central deposition patterns, respectively by visual inspection, whereas in the normal the distribution is homogeneous throughout the lungs. The purpose of the present study was to analyse the distribution of inhaled radioactivity in the lungs by way of matrixes by a computer. The seemingly homogeneous distribution pattern in normal subjects has been found to indicate a gradual change in count profile between the neighboring matrixes. The peripheral pattern indicates the patchy presence of small number of matrixes with excessive radioactivity throughout the lungs, and the central pattern, the presence of matrixes of excessive radioactivity along the major central airways forming a comma-like configuration superimposed on the peripheral pattern. Our computer analysis has a potentiality to characterize obstructive airways disease for a better understanding of their pathophysiology, which is not feasible by a simple visual inspection of images on a polaroid picture. (author)

[en] The mucociliary clearance function was studied by radioaerosol inhalation lung cinescintigraphy and its quantification in 8 patients with pulmonary vascular diseases; pulmonary embolism, 5 cases, and right pulmonary artery hypoplasia, pulmonary arteriovenous fistulas, aortitis syndrome, 1 case each. The mucociliary clearance function was found to be well maintained in pulmonary vascular diseases unless ventilation was disturbed. There was no difference in the mucociliary clearance function between pulmonary embolism and other pulmonary vascular diseases. (author)

[en] The unevenness or inhomogeneity of aerosol deposition patterns on radioaerosol inhalation lung images has been interpreted rather qualitatively in the clinical practice. We have reported our approach to quantitatively analyze the radioactive count distribution on radioaerosol inhalation lung images in relation to the actual lung function data. We have defined multiple indexes to express the shape and the unevenness of the count distribution of the lung images. To reduce as much as possible the number of indexes to be used in the regression functions, the method of selection of variables was introduced to the multiple regression analysis. Because some variables showed greater coefficients of simple correlation, while others did not, multicollinearity of variables had to be taken into consideration. For this reason, we chose a principal components regression analysis. The multiple regression function for each item of pulmonary function data thus established from analysis of 67 subjects appeared usable as a predictor of the actual lung function: for example, % VC (vital capacity) could be estimated by using four indexes out of the multiple ones with a coefficient of multiple correlation (R) of 0.753, and FEVsub(1.0) % (forced expiratory volume in one second divided by forced expiratory volume), by 7 indexes with R = 0.921. Pulmonary function data regarding lung volumes and lung mechanics were estimated more accurately with greater R's than those for lung diffusion, but even in the latter the prediction was still statistically significant at p less than 0.01. We believe the multiple regression functions thus obtained are useful for estimating not only the overall but also the regional function of the lungs. (author)

[en] The term unevenness or inhomogeneity has been used rather vaguely in nuclear medicine to characterize the radioactive distribution in organ images. The purpose of this study was to establish methodology to numerize the unevenness on images and to find the physiological and functional aspects included in uneven images. Using the count profiles of each of the rows and/or columns derived from image matrix data, many indexes, such as size, deposition characteristics and indexes of unevenness of count distribution were defined and computed. The values derived by analyzing count profiles of each row were named horizontal variables. Similar procedures were performed vertically for each column and the values thus obtained were named vertical variables. To evaluate the unevenness of images, two different approaches were tried. One was H + V analysis: the indexes were taken from those size and deposition characteristics, horizontal and vertical variables and their respective means, standard deviation, coefficient of variation and lengths. Thus the total number of indexes was 33 in H + V analysis. Another approach was HV analysis: here disregarding the rows and columns, similar calculations were made for the combined rows and columns for the H and V variables. The total number of indexes was 21 in HV analysis. We applied this method to lung perfusion images and found that at least more than 250 counts per cell (pixel) were necessary for the analysis of unevenness. (author)