Breath expiration times were recorded for 59 patients who underwent hepatic DSA between June 1991 and September 1991 at the Osaka Medical Center for Cancer and Cardiovascular Disease.
Prior to examination, breath expiration time was measured for each patient, and individual expiration times were taken into consideration to time the beginning of the exposure.
Patients' breath expiration times were not measured and were not taken into consideration.
Expiration times of the 59 patients varied from 1.8 seconds to more than 6 seconds, with a 1.8-second expiration time recorded in 1 patient (1.7%), a 2- to 5.9-second expiration time measured in 54 patients (91.5%), and an expiration time of 6 seconds or more measured in four patients (6.8%).
To examine whether variations in expiration time were related to misregistration artifacts, breath expiration times were individually analyzed and each patient's expiration time was taken into consideration during the examination.
Researchers used a digital stopwatch to measure each patient's breath expiration time during fluoroscopic positioning.
As soon as the patient's diaphragm began moving in the cranial direction, the technologist began timing the patient's expiration time with the stopwatch.
For Group A, each patient's breath expiration time was taken into consideration; for Group B, it was not.
No Misregistration Misregistration Patient Group Artifacts Artifacts Group A (Hepatic DSA performed while taking patient's breath expiration time into consideration) 24 (80%) 6 (20%) Group B (Hepatic DSA performed without taking patient's breath expiration time into consideration) 20 (57.1%) 15 (42.9%) Total 44 (67.7%) 21 (32.3%)