Is the RV function measurement affected by inconsistent breath holding during short axis cine stack acquisition?

Background: Variability in the respiratory phase of the breath holds (not consistently at the end-of-expiration) during short-axis-cine-stack acquisition has the potential to introduce errors in left and right ventricle (LV, RV) function measurements. We have shown that respiratory phase variations introduced at basal and apical slices affect LV volumes but not LV ejection fraction (BSCMR 2025). Here, we evaluated if the same variations in respiratory phases affected RV function measurements.


Methods: 21 healthy volunteers were included in this study, each of whom underwent a CMR including two complete short-axis cine stacks; one during end-expiratory breath hold, and the other during end-inspiratory breath-hold, all other parameters remained consistent between the two stacks. A Siemen AERA 1.5T, running XA30 software, was used for acquisitions. The cines were acquired using a retrospectively triggered bSSFP sequence, including 30 phases per slice. Cvi_42 software (Circle Cardiovascular Imaging) with automated endo/epi-cardiac contouring was used to compute RV end-diastolic-volume (RVEDV), end-systolic-volume (RVESV) and ejection-fraction percentage (RVEF%), as well as 2 volume-independent parameters, LV myocardium-mass (LV_Myo_Mass) and LV global-peak-wall-thickness (LV_GPWTh). To simulate variability in the respiratory phase during breath holds, we generated 3 new cine stacks in cvi_42, at 3 ventricular locations: basal, mid and apical, by substituting 2 slices in the end-expiration stack with 2 slices from the end-inspiration stack. The RV volumetric measurements from these 3 new cine stacks were then compared to the end-expiration-cine-stack as the reference standard, using repeated-measures one-way-ANOVA (R-Studio).


Results: No statistical differences were found between end-of-inspiration compared with end-of-expiration for any of the measured parameters. RVEDV, RVESV and RVSV and RVEF% were significantly reduced when respiratory phase variations were inserted at basal level. Moreover, RVEDV, RVESV and RVSV, but not RVEF%, were significantly increased when respiratory phase variations were placed at mid ventricle (highest increase) and at apical level. Finally, LV_Myo_Mass measured in the basal, mid and apical stacks was significantly different compared to the end-of-expiration stack.


Conclusion: The current results provide quantitative evidence of the extent by which RV function measurements are affected by variability in the respiratory depth of the breath holds executed by patients during short-axis-cine-stack acquisition. In contrast to LV, RV ejection fraction is significantly reduced when respiratory phase variations occur at basal level, which might impact the final report.

In conclusion, particularly when RV function is the main target of the CMR scan, variability in the respiratory depth during breath holds should be a concern for radiographers at acquisition time.

RV function parameters measured from 5 cine stacks: End-of-Expiration (EOE), End-of-Inspiration (EOI), APICAL, MID and BASAL. Statistical differences shown by * symbol: *p < 0.05, **p < 0.01, ***p < 0.001, after repeated measures one-way ANOVA (non parametric).

	RVEDV	RVESV	RVSV	RVEF%	LV_Myo_Mass	LV_GPWTh
END-OF-EXPIRATION (EOE)	158.67 +/- 31.93 ml	76.15 +/- 20.67 ml	82.52 +/- 14.46 ml	52.48% +/- 4.85%	90.92 +/- 22.87 g	8.68 +/- 1.44 mm
END-OF-INSPIRATION (EOI)	155.06 +/- 35.24 ml	74.64 +/- 19.76 ml	80.42 +/- 18.68 ml	52.12% +/- 4.76%	88.35 +/- 21.93 g	8.90 +/- 1.92 mm
EOI % diff. EOE	-2.3%	-2.0%	-2.6%	-0.7%	-2.8%	2.6%
APICAL stack	162.67 +/- 33.24 ml	77.54 +/- 20.12 ml	85.12 +/- 16.09 ml	52.66% +/- 4.51%	95.18 +/- 24.19 g	8.69 +/- 1.46 mm
APICAL % diff. EOE	2.5% **	1.8%  *	3.1%  *	0.3%	4.7%  ***	0.1%
MID stack	168.98 +/- 34.98 ml	81.32 +/- 23.88 ml	87.66 +/- 15.23 ml	52.51% +/- 5.90%	93.39 +/- 24.08 g	9.02 +/- 2.06 mm
MID  % diff. EOE	6.5% ***	6.8% ***	6.2%  ***	0.1%	2.7%  ***	3.9%
BASAL stack	132.70 +/- 28.50 ml	70.33 +/- 18.91 ml	62.37 +/- 18.92 ml	46.87% +/- 9.22%	78.09 +/- 17.63 g	8.47 +/ 1.53 mm
BASAL % diff. EOE	-16.4% ***	-7.64%  *	-24.4%  ***	-10.7%  ***	-14.1%  ***	-2.4%

Box plot charts of RV function parameters measured from 5 cine stacks: End-of-Expiration (EOE), End-of-Inspiration (EOI), APICAL, MID and BASAL. Statistical differences shown by * symbol: *p < 0.05, **p < 0.01, ***p < 0.001, after repeated measures one-way ANOVA (non parametric).