Respiratory instructions for CT examinations of the lungs: A hands-oil guide

In computed tomographic (CT) examinations of the lung, accurate visualization of the natural contrast between the low attenuation of air and the relatively higher attenuation of vessels, airways, and interstitial structures requires cooperative and coordinated respiratory maneuvers by the patient. Inadequate respiratory maneuvers can influence differences in lung attenuation and lead to misinterpretation by (a) increasing attenuation to simulate disease in normal patients, (b) decreasing attenuation to simulate normal contrast in patients with disease, or (c) creating motion artifacts. For respiratory maneuvers to be effective, patients have to be instructed before the examination and coached during it. However, comprehensive descriptions of such instructions and coaching are lacking in the radiology literature. Therefore, respiratory instructions specifically for use in thoracic CT examinations have been devised. Along with patient coaching, use of these instructions can improve image quality. With this hands-on guide, both radiologists and technologists can optimize the respiratory instructions given to their patients and thereby improve the quality of thoracic CT examinations. (C) RSNA, 2008.