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  • Open Access

High-dose dobutamine stress SSFP cine MRI at 3 Tesla with patient adaptive local RF shimming using dual-source RF transmission

  • 1,
  • 2,
  • 1,
  • 1,
  • 1,
  • 3,
  • 1 and
  • 1
Journal of Cardiovascular Magnetic Resonance201214 (Suppl 1) :P252

https://doi.org/10.1186/1532-429X-14-S1-P252

  • Published:

Keywords

  • Image Quality
  • Steady State Free Precession
  • Invasive Coronary Angiography
  • Severe Artifact
  • Steady State Free Precession Sequence

Background

Image quality of cine imaging using steady state free precession (SSFP) sequences at 3T is insufficient due to increased RF-inhomogeneity (B1 field) and the high sensitivity of SSFP sequences to off-resonance artefacts. Recently, the introduction of a dual source RF transmission system with patient-adaptive local RF-shimming has led to a significant improvement of image quality of SSFP imaging at 3T.

The objective of this study was to prospectively evaluate the feasibility, image quality and diagnostic accuracy of high-dose dobutamine stress magnetic resonance imaging (DSMR) at 3T comparing dual-source versus single-source transmit technology.

Methods

DSMR was performed in 44 patients with each participant undergoing cine imaging at rest and during dobutamine infusion using both dual- and single-source transmit technology.

B1-maps and measurements of contrast to noise ratio (CNR) were evaluated to quantify the effect of RF calibration in both transmission modes.

Analysis of image quality (0=non diagnostic, 1=severe artifact, 2=slight artifact, 3=no artifact) and wall motion was performed at rest and at maximum stress comparing single- and dual-source technology.

CAD was defined on invasive coronary angiography as the presence of ≥70% stenosis.

Results

The mean percentage of the intended flip angle within the heart increased from 88% ± 9.1 with single-source to 103% ± 5.6 with dual-source (p<0.001). Deviation of the flip angle from the base to the apex along the pseudo-long axis decreased from 29.8% ± 12.9% with single-source to 12.8% ± 7.2% with dual-source.

CNR increased for dual-source vs. single-source especially pronounced at the apex (63.4 ± 24.2 vs. 36.5 ± 16.5, p<0.001) but also at the base (50.1 ± 14.8 vs. 39.3 ± 15.8, p<0.001).

Image quality of dual-source was higher than single-source both at rest (2.8 ± 0.5 vs. 2.6 ± 0.7, p<0.001) and stress (2.5 ± 0.7 vs. 2.0 ± 1.0, p<0.001). The number of segments with either severe artifacts or non-diagnostic image quality at stress was 27% using single-source compared to only 8% using dual-source (figure 1).
Figure 1
Figure 1

Analysis of image quality of DSMR SSFP cine imaging at 3 Tesla. A significant difference existed between the number of segments with severe artifacts and no diagnostic segments comparing single-source and dual-source transmit technology both at rest and even more pronounced at maximum stress.

No significant differences between dual-source DSMR and single-source DSMR were seen regarding sensitivity (92% vs. 83%, p=0.38) and specificity (88% vs. 50%, p=0.25) due to the relatively small patient cohort. Diagnostic accuracy of dual-source DSMR (90%) was significantly higher than single-source DSMR (77%) (p=0.006) (figure 2).

Figure 2

Conclusions

We demonstrated that using a dual-source transmit technology in a standard DSMR protocol is feasible in a 3T environment. Furthermore, the dual-source transmit technology provides better image quality and higher diagnostic accuracy compared to single-source transmit technology.

Funding

None.

Authors’ Affiliations

(1)
Department of Internal Medicine/Cardiology, German Heart Institute Berlin, Berlin, Germany
(2)
Philips Healthcare, Hamburg, Germany
(3)
Philips Healthcare, Best, Netherlands

Copyright

© Berger et al; licensee BioMed Central Ltd. 2012

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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