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

Objective Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. Material and methods The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. Results Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) ( p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration ( p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU ( p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique ( p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. Conclusion Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. Key Points • Suction/Inspiration against resistance is promising to improve contrast density within the pulmonary artery. • Patients potentially suffering pulmonary embolism are able to follow suction/inspiration against resistance. • Contrast density after suction is superior in comparison to other breathing maneuvers.