Has “respiratory coaching” before deep inspiration an impact on the incidence of transient contrast interruption during pulmonary CT angiography?

Abstract

PurposeTo evaluate if respiratory coaching performed prior to CT pulmonary angiography (CTPA) image acquisition has an impact on the occurrence of transient interruption of contrast (TIC) phenomenon.Materials and methodsTwo hundred and thirty-one consecutive patients with suspected pulmonary embolism (PE) were referred for CTPA. They were randomised into two groups, with or without respiratory coaching (groups A and B, respectively). Those patients who were deemed not able to be coached were not randomised and were assigned to a third group (C). Two radiologists evaluated the degree of enhancement of the pulmonary arteries and the presence and grade of TIC. The χ2 test was used to compare differences among groups in occurrence and grade of this phenomenon.ResultsThere were no significant differences in the presence of any grade of TIC among the three groups, with 30 positive cases (32%) in group A, 33 (35%) in group B, and 12 (27%) in group C (P = 0.61). When TIC was graded and divided into significant or not, the different groups also did not differ significantly.ConclusionPerforming respiratory coaching before CTPA had no statistically significant effect on the incidence and severity of TIC in this prospective randomised study.Main Messages• Significant transient interruption of contrast appears in 12% of pulmonary CT angiograms.• Severe transient interruption of contrast leading to nondiagnostic tests appears in 2% of studies.• In our study respiratory coaching has no impact on the incidence of transient interruption of contrast.

Suction/Inspiration against resistance or standardized Mueller maneuver : a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study

“…Despite occasional controversial discussions, there was a general consensus that expiration followed by breathhold leads to an improved contrast in pulmonary arteries in comparison to inspiration followed by breathhold [8][9][10][11][12][13]18]. To our knowledge, the present prospective clinical study is the first to investigate on a patient level how the recently introduced and promising Bsuction against resistance^breathing maneuver might influence contrast behavior compared to other breathing techniques used in clinical routine [14].…”

“…In the last few years, some research groups have postulated that Bexpiration^followed by apnea during injection of the contrast agent might improve the enhancement profile within the PA CT [8][9][10][11][12][13].…”

Indeterminate CT pulmonary angiogram: Why and does it matter?

“…1 Currently, CT pulmonary angiogram (CTPA) has become the standard diagnostic imaging modality to evaluate suspected pulmonary embolism due to its availability, non-invasiveness and rapid examination time. 2 A metaanalysis on utility of thin-slice multidetector CTPA demonstrated high sensitivity and specificity of 74.1% and 89.5% (with a range 57-100% and 68-10%), respectively, supporting CTPA as a valuable imaging tool for the detection of PE. 3 PE has a mortality rate of more than 15% in the first 3 months after diagnosis; hence, it is imperative that correct and accurate diagnosis is attained with the radiological imaging.…”

“…Pulmonary embolism (PE) is a potentially life‐threatening illness and is the third most common acute cardiovascular disease after myocardial infarction and stroke . Currently, CT pulmonary angiogram (CTPA) has become the standard diagnostic imaging modality to evaluate suspected pulmonary embolism due to its availability, non‐invasiveness and rapid examination time . A meta‐analysis on utility of thin‐slice multidetector CTPA demonstrated high sensitivity and specificity of 74.1% and 89.5% (with a range 57–100% and 68–10%), respectively, supporting CTPA as a valuable imaging tool for the detection of PE .…”

“…Mean rate of 6.4% of indeterminate studies is reported in various studies, ranging from 0.5% to 10.8% . Various possible causes of indeterminate and suboptimal CTPA have been proposed . Stephen et al .…”