scholarly journals Metabolite-Specific Echo-Planar Imaging of Hyperpolarized [1-13C]Pyruvate at 4.7 T

Tomography ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 466-476
Author(s):  
Tyler Blazey ◽  
Galen D Reed ◽  
Joel R Garbow ◽  
Cornelius von Morze
Keyword(s):  
Real Time ◽  
Excitation Pulse ◽  
Flip Angle ◽  
Center Frequency ◽  
Planar Imaging ◽  
Resonance Effects ◽  
Frequency Adjustment ◽  
Spectral Selectivity ◽  
Echo Planar

Although hyperpolarization (HP) greatly increases the sensitivity of 13C MR, the usefulness of HP in vivo is limited by the short lifetime of HP agents. To address this limitation, we developed an echo-planar (EPI) sequence with spectral-spatial radiofrequency (SSRF) pulses for fast and efficient metabolite-specific imaging of HP [1-13C]pyruvate and [1-13C]lactate at 4.7 T. The spatial and spectral selectivity of each SSRF pulse was verified using simulations and phantom testing. EPI and CSI imaging of the rat abdomen were compared in the same rat after injecting HP [1-13C]pyruvate. A procedure was also developed to automatically set the SSRF excitation pulse frequencies based on real-time scanner feedback. The most significant results of this study are the demonstration that a greater spatial and temporal resolution is attainable by metabolite-specific EPI as compared with CSI, and the enhanced lifetime of the HP signal in EPI, which is attributable to the independent flip angle control between metabolites. Real-time center frequency adjustment was also highly effective for minimizing off-resonance effects. To the best of our knowledge, this is the first demonstration of metabolite-specific HP 13C EPI at 4.7 T. In conclusion, metabolite-specific EPI using SSRF pulses is an effective way to image HP [1-13C]pyruvate and [1-13C]lactate at 4.7 T.

In vivo perfusion measurements in the human placenta using echo planar imaging at 0.5 T

1998 ◽  
Vol 40 (3) ◽  
pp. 467-473 ◽  
Author(s):  
Penny A. Gowland ◽  
Susan T. Francis ◽  
Keith R. Duncan ◽  
Alan J. Freeman ◽  
Bashar Issa ◽  
...  
Keyword(s):  
Human Placenta ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Perfusion Measurements ◽  
Echo Planar

The clinical potential of ultra-high-speed echo-planar imaging

1990 ◽  
Vol 333 (1632) ◽  
pp. 507-514 ◽  
Keyword(s):  
Real Time ◽  
High Speed ◽  
Echo Planar Imaging ◽  
Lesion Detection ◽  
Whole Body ◽  
Planar Imaging ◽  
Cardiac Events ◽  
Ultra High Speed ◽  
Movement Artefact ◽  
Echo Planar

Ultra-high-speed echo-planar imaging (EP1) allows acquisition of a complete twodimensional image in 64 to 128 ms devoid of movement artefact and without sacrifice of contrast due to relaxation time effects. In conventional whole-body MRI, however, obtrusive movement artefact and extended imaging time, resulting from the need to apply multiple sequences to facilitate lesion detection and pathological characterization, remain limitations. Reduced total examination time increases patient tolerance and throughput • furthermore optimization of contrast to achieve maximal conspicuity of particular features in liver or brain pathology is achieved simply and interactively by real time adjustment of the imaging parameters. The method provides the opportunity to study in real time dynamic events such as flow phenomena in the vascular and cerebrospinal fluid compartments of the brain as well as the kinetics of administered contrast agents, EPI is the only means of capturing the irregular motion of aperiodic cardiac events and bowel peristalsis.

scholarly journals Real-Time 3D Laparoscopic Ultrasonography

2005 ◽  
Vol 27 (3) ◽  
pp. 129-144 ◽  
Author(s):  
Edward D. Light ◽  
Salim F. Idriss ◽  
Kathryn F. Sullivan ◽  
Patrick D. Wolf ◽  
Stephen W. Smith
Keyword(s):  
Real Time ◽  
Insertion Loss ◽  
Pulmonary Veins ◽  
Intracardiac Echocardiography ◽  
Center Frequency ◽  
Ultrasound Transducers ◽  
Laparoscopic Ultrasonography ◽  
Chamber View ◽  
2D Array

We have previously described 2D array ultrasound transducers operating up to 10 MHz for applications including real time 3D transthoracic imaging, real time volumetric intracardiac echocardiography (ICE), real time 3D intravascular ultrasound (IVUS) imaging, and real time 3D transesophageal echocardiography (TEE). We have recently built a pair of 2D array transducers for real time 3D laparoscopic ultrasonography (3D LUS). These transducers are intended to be placed down a trocar during minimally invasive surgery. The first is a forward viewing 5 MHz, 11 times 19 array with 198 operating elements. It was built on an 8 layer multilayer flex circuit. The interelement spacing is 0.20 mm yielding an aperture that is 2.2 mm × 3.8 mm. The O.D. of the completed transducer is 10.2 mm and includes a 2 mm tool port. The average measured center frequency is 4.5 MHz, and the −6 dB bandwidth ranges from 15% to 30%. The 50 Ω insertion loss, including Gore MicroFlat cabling, is −81.2 dB. The second transducer is a 7 MHz, 36 times 36 array with 504 operating elements. It was built upon a 10 layer multilayer flex circuit. This transducer is in the forward viewing configuration and the interelement spacing is 0.18 mm. The total aperture size is 6.48 mm x 6.48 mm. The O.D. of the completed transducer is 11.4 mm. The average measured center frequency is 7.2 MHz, and the −6 dB bandwidth ranges from 18% to 33%. The 50 Ω insertion loss is −79.5 dB, including Gore MicroFlat cable. Real-time in vivo 3D images of canine hearts have been made including an apical 4-chamber view from a substernal access with the first transducer to monitor cardiac function. In addition, we produced real time 3D rendered images of the right pulmonary veins from a right parasternal access with the second transducer, which would be valuable in the guidance of cardiac ablation catheters for treatment of atrial fibrillation.

Real-time flow measurements using echo-planar imaging

1991 ◽  
Vol 18 (1) ◽  
pp. 1-8 ◽  
Author(s):  
D. N. Guilfoyle ◽  
P. Gibbs ◽  
R. J. Ordidge ◽  
P. Manwield
Keyword(s):  
Real Time ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
Flow Measurements ◽  
Time Flow ◽  
Echo Planar

scholarly journals Comparison of Real-Time Water Proton Spectroscopy and Echo-Planar Imaging Sensitivity to the BOLD Effect at 3 T and at 7 T

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e91620 ◽  
Author(s):  
Yury Koush ◽  
Mark A. Elliott ◽  
Frank Scharnowski ◽  
Klaus Mathiak
Keyword(s):  
Real Time ◽  
Echo Planar Imaging ◽  
Water Proton ◽  
Planar Imaging ◽  
Proton Spectroscopy ◽  
Bold Effect ◽  
Echo Planar

scholarly journals Real-time geometric distortion correction for interventional imaging with echo-planar imaging (EPI)

2009 ◽  
Vol 61 (4) ◽  
pp. 994-1000 ◽  
Author(s):  
Iulius Dragonu ◽  
Baudouin Denis de Senneville ◽  
Bruno Quesson ◽  
Chrit Moonen ◽  
Mario Ries
Keyword(s):  
Real Time ◽  
Echo Planar Imaging ◽  
Distortion Correction ◽  
Geometric Distortion ◽  
Planar Imaging ◽  
Interventional Imaging ◽  
Echo Planar
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