Abstract Archives of the RSNA, 2012


SSC02-07

True Real-Time Cardiac MRI with Radial K-Space Sampling in Free Breathing without ECG-synchronization—Improved Image Quality with Iterative Image Reconstruction

Scientific Formal (Paper) Presentations

Presented on November 26, 2012
Presented as part of SSC02: Cardiac (Anatomy and Function II)

Participants

Ralf W. Bauer MD, Presenter: Research Consultant, Siemens AG Speakers Bureau, Siemens AG
Isabel Radtke BSC, Abstract Co-Author: Nothing to Disclose
Martin Uecker, Abstract Co-Author: Research collaboration, Siemens AG
Shuo Zhang MS, Abstract Co-Author: Research collaboration, Siemens AG
Kai Tobias Block, Abstract Co-Author: Employee, Siemens AG
Thomas G. Graf PhD, Abstract Co-Author: Employee, Siemens AG
Josef Matthias Kerl MD, Abstract Co-Author: Research Consultant, Siemens AG Speakers Bureau, Siemens AG
Thomas Josef Vogl MD, PhD, Abstract Co-Author: Nothing to Disclose
Maya Christina Larson, Abstract Co-Author: Nothing to Disclose

PURPOSE

Radial k-space sampling often suffers from artifacts and low signal when aiming at high temporal resolution. We investigated the role of iterative reconstruction concerning image quality and temporal resolution of a novel TrueFISP sequence based on radial k-space sampling (rTrueFISP) for real-time functional cardiac evaluation compared to standard balanced steady-state free precision (bSSFP).

METHOD AND MATERIALS

12 healthy volunteers (mean age 27 y, mean heart rate 71±10 bpm) underwent 1.5 T cardiac MRI. Single-shot short axis views (8 mm slabs, 20% gap) were acquired with a) retrospectively ECG-gated segmented bSSFP in breath-hold and b) free breathing non-ECG-synchronized rTrueFISP with sliding-window (5 subframes) or iterative image (IR) reconstruction with a temporal resolution per single image of 36 fr/s. Left ventricular functional parameters (EDV, ESV, EF) were determined according to the Simpson’s rule with bSSFP representing the reference standard. Contrast-to-noise-ratio (CNR) of myocardium/blood pool was calculated. Subjective image quality was assessed by two radiologists (1=excellent, 6=non-diagnostic).

RESULTS

LV functional parameters showed strong correlation (r=0.97-98; p<0.001) between bSSFP and rTrueFISP with both different ways of image reconstruction (EF: 68±6% vs. 67±6% vs 66±6%). CNR (15.2 vs. 8.5 vs. 16.4) and overall subjective image quality (1.9±0.8 vs. 1.6±0.5) significantly improved with IR compared to sliding-window rTrueFISP and was comparable to bSSFP. Foremost, artifact burden was significantly reduced.

CONCLUSION

The implementation of iterative image reconstruction in real-time free-breathing non-ECG-gated rTrueFISP imaging significantly reduces artifacts and improves overall image quality, while the accuracy of LV functional analysis in comparison with the standard ECG-gated breath-hold cine bSSFP sequences was maintained.

CLINICAL RELEVANCE/APPLICATION

With improved image quality real-time cardiac MRI with radial k-space sampling took an important step for the acceptance and robustness of this novel sequence for clinical use in actual patients.

Cite This Abstract

Bauer, R, Radtke, I, Uecker, M, Zhang, S, Block, K, Graf, T, Kerl, J, Vogl, T, Larson, M, True Real-Time Cardiac MRI with Radial K-Space Sampling in Free Breathing without ECG-synchronization—Improved Image Quality with Iterative Image Reconstruction.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12026589.html