Juan Arenas MD, Presenter: Nothing to Disclose

Cristina García-Espasa, Abstract Co-Author: Nothing to Disclose

Juan-Matías Bernabes, Abstract Co-Author: Nothing to Disclose

Jose Sánchez-Payá PhD, Abstract Co-Author: Nothing to Disclose

Javier De la Hoz, Abstract Co-Author: Nothing to Disclose

Joan Carreres, Abstract Co-Author: Nothing to Disclose

Transient contrast interruption (TCI) is a vascular phenomenon causing low-quality or non-diagnostic pulmonary CT angiograms. Deep inspiration is suggested as the cause of the artifact, and the effect of respiratory training with several inspiratory and expiratory cycles just before the CT scan is unclear. So, to evaluate if performing a different respiratory protocol has an impact on the frequency of TCI, we conducted this prospective randomized study.

Of 231 consecutive patients, those who were presumed to collaborate to perform respiratory manoeuvres were ramdomized to either group A, who were asked to make the inspiratory effort at the beginning of the scan, without previous training, or group B, who made a “respiratory training” with several deep inspirations and expirations just before and during contrast infusion, followed by a deep inspiration just at the beginning of the scan. Those patients who were considered not able to collaborate formed a third group C. Age, sex, weight, height and injection rate were  registered.  Images were blindly reviewed by two radiologists who evaluated contrast enhancement of pulmonary arteries at different levels and the presence and grade of TIC.  

There were 118 male and 113 female patients (mean age, 65 years; range, 18–93 years) in the final evaluation. Ninety-four patients were randomized to protocol A, 92 to protocol B and 45 non-collaborative patients were assigned to group C. There were no statistically significant difference among groups.  The number of patients presenting any grade of TIC were 33 (35%) in group A, 30 (32%) in B, and 12 (27%) in C (non significant differences). When TIC phenomenom was graded and divided in significant or not, differences had also no statistically significance, with 14 (15%), 10 (11%) and 4 (9%) patients in groups A, B and C, respectively. No other registered variable was associated with the detection of TIC phemomenon.  

Performing a respiratory training, with several inspiratory and expiratory cycles before inspiration, preceeding CT pulmonary angiography, has no effect on the incidence of transient interruption of contrast phenomenom in this prospective randomized study.  

The incidence of transient interruption of contrast on CT pulmonary angiography is not affected by performing respiratory training with  respiratory cycles before scanning.

Arenas, J, García-Espasa, C, Bernabes, J, Sánchez-Payá, J, De la Hoz, J, Carreres, J, Effect of  “Respiratory Training” Before Deep Inspiration in Pulmonary CT Angiography: Prospective Randomized Study Evaluating the Incidence of Transient Contrast Interruption.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6012951.html