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Undersampled cine 3D tagging for rapid assessment of cardiac motion.

Stoeck CT, Manka R, Boesiger P, Kozerke S - J Cardiovasc Magn Reson (2012)

Bottom Line: Comparison of results from fully sampled in-vivo data acquired with prospectively undersampled acquisitions showed a mean difference in circumferential shortening of -0.14 ± 5.18% and 0.71 ± 6.16% for R = 3 and 4.In patients peak, circumferential shortening was significantly reduced (p < 0.002 for all patients) in regions with late gadolinium enhancement.Undersampled cine 3D tagging enables significant reduction in scan time of whole-heart tagging and facilitates quantification of shortening, rotation and torsion of the left ventricle without adding significant errors compared to previous 3D tagging approaches.

View Article: PubMed Central - PubMed

Affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Gloriastrasse 35, 8092, Zurich, Switzerland.

ABSTRACT

Background: CMR allows investigating cardiac contraction, rotation and torsion non-invasively by the use of tagging sequences. Three-dimensional tagging has been proposed to cover the whole-heart but data acquisition requires three consecutive breath holds and hence demands considerable patient cooperation. In this study we have implemented and studied k-t undersampled cine 3D tagging in conjunction with k-t PCA reconstruction to potentially permit for single breath-hold acquisitions.

Methods: The performance of undersampled cine 3D tagging was investigated using computer simulations and in-vivo measurements in 8 healthy subjects and 5 patients with myocardial infarction. Fully sampled data was obtained and compared to retrospectively and prospectively undersampled acquisitions. Fully sampled data was acquired in three consecutive breath holds. Prospectively undersampled data was obtained within a single breath hold. Based on harmonic phase (HARP) analysis, circumferential shortening, rotation and torsion were compared between fully sampled and undersampled data using Bland-Altman and linear regression analysis.

Results: In computer simulations, the error for circumferential shortening was 2.8 ± 2.3% and 2.7 ± 2.1% for undersampling rates of R = 3 and 4 respectively. Errors in ventricular rotation were 2.5 ± 1.9% and 3.0 ± 2.2% for R = 3 and 4. Comparison of results from fully sampled in-vivo data acquired with prospectively undersampled acquisitions showed a mean difference in circumferential shortening of -0.14 ± 5.18% and 0.71 ± 6.16% for R = 3 and 4. The mean differences in rotation were 0.44 ± 1.8° and 0.73 ± 1.67° for R = 3 and 4, respectively. In patients peak, circumferential shortening was significantly reduced (p < 0.002 for all patients) in regions with late gadolinium enhancement.

Conclusion: Undersampled cine 3D tagging enables significant reduction in scan time of whole-heart tagging and facilitates quantification of shortening, rotation and torsion of the left ventricle without adding significant errors compared to previous 3D tagging approaches.

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Related in: MedlinePlus

Sequence diagram (a) and sampling pattern for k-t undersampling (b). After detection of the R-wave the tagging preparation is applied, followed by two repetitions of undersampled data and training data acquisitions for each stack.
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Figure 2: Sequence diagram (a) and sampling pattern for k-t undersampling (b). After detection of the R-wave the tagging preparation is applied, followed by two repetitions of undersampled data and training data acquisitions for each stack.

Mentions: All simulations were performed in Matlab (The MathWorks, Natick, MA, USA). Three orthogonal stacks with line tagging modulation in readout direction were generated (Figure 1a). The CSPAMM method [14] was simulated to avoid tag line fading. The model consisted of a contracting left ventricle as well as static tissue representing chest wall and liver. Circumferential shortening and rotation as measured in a healthy subject at basal and apical level was linearly interpolated along the long-axis to create three-dimensional motion data. Peak circumferential shortening was 18.8% and 17.8% for base and apex, respectively. Peak rotation was −3.2° and 10.3° for base and apex (Figure 1b-d). Longitudinal shortening obtained from the same in-vivo subject was incorporated. Simulations of undersampled data acquisition were compared to fully sampled simulated data sets with equivalent spatial and temporal resolution. The matrix size was set according to practical values [24,25] (Table 1). Gaussian noise was added to k-space data before undersampling resulting in a SNR of 25 prior to undersampling. Both undersampled and training data were extracted from the computer model (Figure 2b). Undersampling rates of R = 3, 4, 5 and 8 were simulated. In all simulations, five training profiles were used in ky and kz direction resulting in a total of 25 training profiles.


Undersampled cine 3D tagging for rapid assessment of cardiac motion.

Stoeck CT, Manka R, Boesiger P, Kozerke S - J Cardiovasc Magn Reson (2012)

Sequence diagram (a) and sampling pattern for k-t undersampling (b). After detection of the R-wave the tagging preparation is applied, followed by two repetitions of undersampled data and training data acquisitions for each stack.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472184&req=5

Figure 2: Sequence diagram (a) and sampling pattern for k-t undersampling (b). After detection of the R-wave the tagging preparation is applied, followed by two repetitions of undersampled data and training data acquisitions for each stack.
Mentions: All simulations were performed in Matlab (The MathWorks, Natick, MA, USA). Three orthogonal stacks with line tagging modulation in readout direction were generated (Figure 1a). The CSPAMM method [14] was simulated to avoid tag line fading. The model consisted of a contracting left ventricle as well as static tissue representing chest wall and liver. Circumferential shortening and rotation as measured in a healthy subject at basal and apical level was linearly interpolated along the long-axis to create three-dimensional motion data. Peak circumferential shortening was 18.8% and 17.8% for base and apex, respectively. Peak rotation was −3.2° and 10.3° for base and apex (Figure 1b-d). Longitudinal shortening obtained from the same in-vivo subject was incorporated. Simulations of undersampled data acquisition were compared to fully sampled simulated data sets with equivalent spatial and temporal resolution. The matrix size was set according to practical values [24,25] (Table 1). Gaussian noise was added to k-space data before undersampling resulting in a SNR of 25 prior to undersampling. Both undersampled and training data were extracted from the computer model (Figure 2b). Undersampling rates of R = 3, 4, 5 and 8 were simulated. In all simulations, five training profiles were used in ky and kz direction resulting in a total of 25 training profiles.

Bottom Line: Comparison of results from fully sampled in-vivo data acquired with prospectively undersampled acquisitions showed a mean difference in circumferential shortening of -0.14 ± 5.18% and 0.71 ± 6.16% for R = 3 and 4.In patients peak, circumferential shortening was significantly reduced (p < 0.002 for all patients) in regions with late gadolinium enhancement.Undersampled cine 3D tagging enables significant reduction in scan time of whole-heart tagging and facilitates quantification of shortening, rotation and torsion of the left ventricle without adding significant errors compared to previous 3D tagging approaches.

View Article: PubMed Central - PubMed

Affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Gloriastrasse 35, 8092, Zurich, Switzerland.

ABSTRACT

Background: CMR allows investigating cardiac contraction, rotation and torsion non-invasively by the use of tagging sequences. Three-dimensional tagging has been proposed to cover the whole-heart but data acquisition requires three consecutive breath holds and hence demands considerable patient cooperation. In this study we have implemented and studied k-t undersampled cine 3D tagging in conjunction with k-t PCA reconstruction to potentially permit for single breath-hold acquisitions.

Methods: The performance of undersampled cine 3D tagging was investigated using computer simulations and in-vivo measurements in 8 healthy subjects and 5 patients with myocardial infarction. Fully sampled data was obtained and compared to retrospectively and prospectively undersampled acquisitions. Fully sampled data was acquired in three consecutive breath holds. Prospectively undersampled data was obtained within a single breath hold. Based on harmonic phase (HARP) analysis, circumferential shortening, rotation and torsion were compared between fully sampled and undersampled data using Bland-Altman and linear regression analysis.

Results: In computer simulations, the error for circumferential shortening was 2.8 ± 2.3% and 2.7 ± 2.1% for undersampling rates of R = 3 and 4 respectively. Errors in ventricular rotation were 2.5 ± 1.9% and 3.0 ± 2.2% for R = 3 and 4. Comparison of results from fully sampled in-vivo data acquired with prospectively undersampled acquisitions showed a mean difference in circumferential shortening of -0.14 ± 5.18% and 0.71 ± 6.16% for R = 3 and 4. The mean differences in rotation were 0.44 ± 1.8° and 0.73 ± 1.67° for R = 3 and 4, respectively. In patients peak, circumferential shortening was significantly reduced (p < 0.002 for all patients) in regions with late gadolinium enhancement.

Conclusion: Undersampled cine 3D tagging enables significant reduction in scan time of whole-heart tagging and facilitates quantification of shortening, rotation and torsion of the left ventricle without adding significant errors compared to previous 3D tagging approaches.

Show MeSH
Related in: MedlinePlus