Lateral-view ventilation images with 133Xe.

For better delineation of regional ventilation abnormalities, a lateral-view imaging has been employed when one or more areas of abnormal retention were visible in posterior views of 133Xe washout images. It is technically simple to obtain lateral views during the 133Xe washout phase. The resulting images were found to be very useful in detecting regions of ventilation-perfusion mismatch and in evaluating regional obstructive lung disease.