Regional Pulmonary Function Studied With Xenon133*

Abstract

Although there are many tests of pulmonary function in common usage, most of these measure only over-all function and are incapable of describing separately the behavior of different parts of the lung. Pulmonary arteriography has proven to be a valuable procedure for estimating the distribution of blood flow through the lungs but does not provide quantitative results. By bronchospirometry it has been possible to measure separately the ventilation and oxygen uptake of the two lungs or even of individual lobes, but considerable skill is required to obtain valid results, and the measurements must be made under conditions which are quite unphysiological. Both arteriography and bronchospirometry, furthermore, are unpleasant for the patient and are not without hazard.The use of a radioactive tracer gas for assessing regional ventilation was reported in 1955 by Knipping and co-workers (2). They recorded external counting rate over multiple areas of the chest during breathing of air containing xenon'33 and were able to show the presence of unventilated or markedly underventilated areas in certain patients. In subsequent publications (3-8), these and other workers extended their observations and described a method of displaying the results pictorially but did not attempt to estimate regional ventilation quantitatively.More recently, Dyson and co-workers (9) have described the use of oxygen15 with external

Quantitative analysis of regional airways obstruction using dynamic hyperpolarized 3He MRI—Preliminary results in children with cystic fibrosis

“…Errors will be introduced by the process of coalescing the spatially localized information into a global index for comparison with spirometry. In clinical practice, radionuclide ventilation scintigraphy is the only means of assessing regional dynamic ventilation (22,23). However, it has poor temporal resolution and involves the use of radioactive substances, albeit with low radiation exposure for the patient.…”

Computed Tomography Studies of Lung Mechanics

“…Invasive techniques, including the retrograde catheter (4,5), alveolar capsule (6), and implanted radiopaque markers (7), added greatly to our understanding of regional lung function but obviously could not be applied in human disease. The use of noninvasive imaging methods, initially with lowresolution planar detectors and radioactive tracer gases (8) and then by tomographic methods of increasing resolution and volumetric data acquisition (9-13) (again, enhanced by coupling to models of distributed lung function [14]), now provides an unprecedented capability for understanding regional lung mechanical function in general as well as in individual patients.…”

Functional Imaging: CT and MRI

“…Attempts have been made to quantify regional ventilation both directly and indirectly with a variety of invasive techniques or radioisotope imaging (87)(88)(89)(90)(91)(92)(93)(94)(95)(96), but these methods have been limited by invasiveness, poor spatial and temporal resolution, qualitative nature, and/or complexity. Xenon-enhanced MDCT (Xe-MDCT) is a method for the non-invasive measurement of regional pulmonary ventilation, determined from the wash-in and/or wash-out rates of the radiodense, non-radioactive gas xenon as measured in serially acquired, axial MDCT scans.…”