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Highly accelerated real-time T2-weighted imaging with through-time radial GRAPPA and low-latency GPU reconstruction

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Journal of Cardiovascular Magnetic Resonance201416 (Suppl 1) :W33

  • Published:


  • Acute Myocardial Infarction
  • High Temporal Resolution
  • Acute Injury
  • Radial Sequence
  • Latency Reconstruction


T2-weighted cardiac images are commonly used for edema detection [14]. However, neither black-blood TSE nor cine images can offer real-time edema monitoring, and are therefore not suitable for the guidance of cardiac ablation procedures. We proposed a radial T2-weighted interrupted balanced SSFP (rT2W-iSSFP), a real-time high temporal resolution sequence targeted at monitoring edema.



rT2W-iSSFP generates T2-weighting with a series of 180° RF pulses. TE-effective for the radial sequence is defined as the time from the beginning of the train to the median imaging echo. rT2W-iSSFP also incorporates through-time radial GRAPPA to achieve high temporal resolution with high degrees of acceleration (R = 8) [5], (Figure 1) which was implemented on a 48-core hybrid system with a GPU (Tesla C1060, NVIDIA), achieving 10-20 fps image acquisition with 20 ms latency reconstruction and image display [6].
Figure 1
Figure 1

Illustration of the acquisition scheme, flip angles and k-space sampling pattern of rT 2 W-iSSFP. Four-fold acceleration is shown in this example. Images were reconstructed using through-time radial GRAPPA with a low-latency implementation. Typically a 192 × 192 matrix and an acceleration rate of R = 8 is used.


Bloch equation simulations were performed to evaluate the T2-weighting and the image quality of rT2W-iSSFP using a variant of the Shepp-Logan phantom containing 3 ellipsoids with different T1s and T2s to represent cerebrospinal fluid (CSF), liver, and myocardium (Figure 2a) [7, 8]. T2-weighted turbo spin echo (T2W-TSE) was also simulated [3, 9]. TE-effective was 60 ms for both T2W-TSE and rT2W-iSSFP.
Figure 2
Figure 2

(a) Illustration of the Shepp-Logan phantom used for simulation. (b) T2W-TSE and (c) r T2W-iSSFP were simulated. Swine with acute injury was scanned by (d) breath-hold T2W-TSE and (e) free-breathing r T2W-iSSFP as well. The edema (the arrows in d) is depicted in both d and e. In both simulation and in-vivo imaging, T2W-TSE was used as the reference of T2-weighting. Tacq - acquisition time.

Animal Model

Swine with acute injury (N = 2) were imaged on a 1.5T scanner (Avanto, Siemens, Germany). Free-breathing ECG-triggered single-shot rT2W-iSSFP was acquired (TE-effective = 80 ms; TR = 3 ms; matrix = 192 × 192; 3 slices per heartbeats). ECG-triggered, breath-held T2W-TSE (TE = 80 ms, resolution = 1 × 1 mm2, matrix = 192 × 192) was used as a reference.


The results from simulation of T2W-TSE and rT2W-iSSFP are shown in Figures 2b and 2c. The intensity difference between CSF and liver is similar in T2W-TSE and rT2W-iSSFP. Streaking artifacts are seen in Figure 2c, but these are not pronounced in in vivo images. Four-chamber views of swine heart from T2W-TSE (breath-hold) and rT2W-iSSFP (free-breathing) are shown in Figures 2d and 2e. Edema at the anteroseptal region due to acute myocardial infarction is depicted (the arrows in d).


rT2W-iSSFP offers high temporal resolution T2-weighted imaging with image quality sufficient for visualization of edema from acute injury. rT2W-iSSFP can be applied to real-time monitoring of edema formation during cardiac interventions.

Authors’ Affiliations

Biomedical Engineering, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
Biomedical Engineering, Tsinghua University, Beijing, China
Siemens Healthcare USA, Inc., Chicago, Illinois, USA
Cardiology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
Radiology, Case Western Reserve University, Cleveland, Ohio, USA
Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA


  1. Kellman, et al: MRM. 2007Google Scholar
  2. Vergara, et al: Heart Rhythm. 2010Google Scholar
  3. Simonetti, et al: Radiology. 1996Google Scholar
  4. Dharmakumar, et al: MRM. 2006Google Scholar
  5. Seiberlich, et al: MRM. 2011Google Scholar
  6. Saybasili, et al: ISMRM. 2013Google Scholar
  7. Paul, et al: MRM. 2006Google Scholar
  8. Derbyshire, et al: MRM. 2005Google Scholar
  9. Hennig, et al: MRM. 1986Google Scholar


© Xu et al.; licensee BioMed Central Ltd. 2014

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