Imaging diagnosis of gas exchange in patients with lung cancer

Functional images of the ventilation-perfusion ratios and the mean transit time of Xe-133 were then obtained through computer analysis. In addition, an overall lung function test and arterial blood gas analysis were carried out on the same day. %V radical with Kr-81m during tidal breathing expressed as the percentage of tumor-bearing lung to total lung correlated significantly with %VC(r=0.666, p<0.0005). Likewise, there was a significant correlation (r=0.713, p<0.005) between %VC and %Q radical with Tc-99m MAA. The correlation coefficient between the relative mean transit time of Xe-133 and FEVsub(1.0)% was -0.433(p<0.1). On the other hand, FEVsub(1.0)% did not correlate with %V radical with Kr-81m and %Q radical Tc-99m MAA. Ventilation and perfusion in the affected lung showed no significant difference between UICC.TNM stages I and II. In stages III and IV, however, regional ventilation and perfusion decreased significantly. The T factor had a more serious influence on ventilation and perfusion in the affected lung than the N factor. The V radical sub(A)/Q radical sub(C) distribution was calculated from the functional image of the ventilation-perfusion ratios in 17 cases with lung cancer. Four types of V radical sub(A)/Q radical sub(C) distribution were found: Type I (a pattern with nearly normal distribution) was observed in 8 of 17 cases, Type II (a pattern with a high V radical sub(A)/Q radical area) was seen in 7 cases, Type III (a pattern with a low V radical sub(A)/Q radical area) was seen in one case, and Type IV (a pattern with both a high and low V radical sub(A)/Q radical area) was found in the remaining case. The functional image obtained with ventilation-perfusion scintigraphy allowed visual and quantitative evaluation of changes of regional lung function and provided important information on regional ventilation and perfusion in patients with lung cancer. (J.P.N.)