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Suction against resistance: a new breathing technique to significantly improve the blood flow ratio of the superior and inferior vena cava

Journal Paper/Review - Aug 9, 2014

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Citation
Gutzeit A, Roos J, Hergan K, von Weymarn C, Wälti S, Reischauer C, Froehlich J. Suction against resistance: a new breathing technique to significantly improve the blood flow ratio of the superior and inferior vena cava. Eur Radiol 2014; 24:3034-41.
Project
Type
Journal Paper/Review (English)
Journal
Eur Radiol 2014; 24
Publication Date
Aug 9, 2014
Issn Print
Issn Electronic
1432-1084
Pages
3034-41
Publisher
Brief description/objective

OBJECTIVES
Optimal contrast within the pulmonary artery is achieved by the maximum amount of contrast-enhanced blood flowing through the superior vena cava (SVC), while minimum amounts of non-contrasted blood should originate from the inferior vena cava (IVC). This study aims to clarify whether "suction against resistance" might optimise this ratio.

METHODS
Phase-contrast pulse sequences on a 1.5T MRI magnet were used for flow quantification (mean flow (mL/s), stroke volume (Vol) in the SVC and IVC in volunteers. Different breathing manoeuvers were analysed repeatedly: free breathing; inspiration; expiration; suction against resistance, and Valsalva. To standardise breathing commands, volunteers performed suction and Valsalva manoeuvers with an MR-compatible manometer.

RESULTS
Suction against resistance was associated with a significant drop of the IVC/SVC flow quotient (1.63 [range 1.3-2.0] p < 0.05 at -10 mmHg and 1.48 [1.1-1.9] p < 0.01 at -20 mmHg) corresponding to increased blood flow from SVC and diminished flow originating from the IVC. The remaining breathing commands (free breathing 2.2; inspiration 2.4; expiration 2.4; Valsalva 10 mmHg 2.3; Valsalva 20 mmHg 2.6; and Valsalva 30 mmHg 2.2) showed no differences (p > 0.05).

CONCLUSIONS
Suction against resistance caused a significant drop in the IVC/SVC quotient. Theoretically, this breathing manoeuver might significantly improve the enhancement characteristics of CT angiography.

KEY POINTS
Suction provokes reduction in blood flow in the inferior vena cava. Ratio between the inferior and superior vena cava blood flow diminished during suction. Manometer used during breathing standardises MR phase-contrast blood flow measurements.