Functional residual capacity breath hold for subtraction image of dynamic liver MRI

The involuntary respiratory muscle contractions that occur during breath holding were found in almost all of 52 subjects and were regular in a majority. In detailed studies, subjects rebreathed a mixture of 8% CO2 in O2 and then held their breath on an occluded mouthpiece, with glottis open, at functional residual capacity. Contractions monitored as waves of negative pressure were reproducible and increased in amplitude and frequency through the breath hold, but the breakpoint did not always correspond to the same pressure or frequency. Frequency and the time derivative of pressure (dP/dt) of contractions were much higher during breath holding than frequency of breathing and dP/dt of occluded breaths at the same gas tensions during rebreathing. Contractions were reduced in amplitude after the subject took three breaths without altering gas tensions. The results are consistent with the hypothesis that contractions contribute to dyspnea in breath breath holding, but there is not a simple correlation between their magnitude and the degree of dyspnea.

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High resolution T2 weighted liver MR imaging using functional residual capacity breath-hold with a 1.0-Tesla scanner

European Journal of Radiology ◽

10.1016/j.ejrad.2008.07.007 ◽

2009 ◽

Vol 72 (2) ◽

pp. 300-305 ◽

Cited By ~ 2

Author(s):

Akihiko Tabuchi ◽

Toshizo Katsuda ◽

Rumi Gotanda ◽

Tatsuhiro Gotanda ◽

Masahiko Mitani ◽

...

Keyword(s):

High Resolution ◽

Mr Imaging ◽

Functional Residual Capacity ◽

Breath Hold ◽

Residual Capacity ◽

Tesla Scanner

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Postinspiratory mixing in the lung and cardiogenic oscillations

Journal of Applied Physiology ◽

10.1152/jappl.1981.51.4.922 ◽

1981 ◽

Vol 51 (4) ◽

pp. 922-928 ◽

Cited By ~ 9

Author(s):

R. Arieli ◽

A. J. Olszowka ◽

H. D. Van Liew

Keyword(s):

Mechanical Properties ◽

Functional Residual Capacity ◽

Pressure Wave ◽

Phase Iii ◽

Breath Hold ◽

Residual Volume ◽

Residual Capacity ◽

Expired Gas ◽

Cardiogenic Oscillations ◽

Phase Iv

Subjects inspired a 300-ml bolus of indicator gas cocktail (5% each of SF6, Ar, Ne, and He) form residual volume (RV), then inspired air to functional residual capacity (FRC). There was no evidence that a 10-s breath hold changed the relative concentrations or amounts of indicator gases in phases III and IV of expiration or allowed additional gas to mix into the RV, but the breath hold caused cardiogenic oscillations (CO) in expired gas to decrease in height. The units responsible for cardiogenic troughs and peaks are different from the units responsible for phases III and IV, respectively, in that the oscillation troughs had a lower He/SF6 ratio than the peaks whereas phase III had a higher He/SF6 than phase IV. We explain the CO as due to variation in mechanical properties, leading to variation in response to the pressure wave caused by the heart, in units that are relatively near to each other. We conclude that there is little or no postinspiratory mixing between distant lung units, but the dampening of CO suggests that units that are close to each other can mix if time is allowed.

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