Lim, Song-I
(Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine)
,
Woo, Chul-Woong
(Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine)
,
Kim, Sang-Tae
(Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine)
,
Choe, Bo-Young
(Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea)
,
Woo, Dong-Cheol
(Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine)
The objective of this study was to describe a radiofrequency (RF) coil design for in vivo sodium magnetic resonance imaging (MRI) for use in small animals. Accumulating evidence has indicated the importance and potential of sodium imaging with improved magnet strength (> 7T), faster gradient, better...
The objective of this study was to describe a radiofrequency (RF) coil design for in vivo sodium magnetic resonance imaging (MRI) for use in small animals. Accumulating evidence has indicated the importance and potential of sodium imaging with improved magnet strength (> 7T), faster gradient, better hardware, multi-nucleus imaging methods, and optimal coil design for patient and animal studies. Thus, we developed a saddle-shaped sodium volume coil with a diameter/length of 30/30 mm. To evaluate the efficiency of this coil, bench-level measurement was performed. Unloaded Q value, loaded Q value, and ratio of these two values were estimated to be 352.8, 211.18, and 1.67, respectively. Thereafter, in vivo acquisition of sodium images was performed using normal mice (12 weeks old; n = 5) with a two-dimensional gradient echo sequence and minimized echo time to increase spatial resolution of images. Sodium signal-to-noise ratio in mouse kidneys (renal cortex, medulla, and pelvis) was measured. We successfully acquired sodium MR images of the mouse kidney with high spatial resolution (approximately 0.625 mm) through a combination of sodium-proton coils.
The objective of this study was to describe a radiofrequency (RF) coil design for in vivo sodium magnetic resonance imaging (MRI) for use in small animals. Accumulating evidence has indicated the importance and potential of sodium imaging with improved magnet strength (> 7T), faster gradient, better hardware, multi-nucleus imaging methods, and optimal coil design for patient and animal studies. Thus, we developed a saddle-shaped sodium volume coil with a diameter/length of 30/30 mm. To evaluate the efficiency of this coil, bench-level measurement was performed. Unloaded Q value, loaded Q value, and ratio of these two values were estimated to be 352.8, 211.18, and 1.67, respectively. Thereafter, in vivo acquisition of sodium images was performed using normal mice (12 weeks old; n = 5) with a two-dimensional gradient echo sequence and minimized echo time to increase spatial resolution of images. Sodium signal-to-noise ratio in mouse kidneys (renal cortex, medulla, and pelvis) was measured. We successfully acquired sodium MR images of the mouse kidney with high spatial resolution (approximately 0.625 mm) through a combination of sodium-proton coils.
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제안 방법
The advantage of microstrip transmission line includes its simple design without the need for lumped elements (12). Although non-shielded RF coils were designed and developed in this study, traditional RF surface coils could be used to modify microstrip transmission line type in order to improve their performance. Primarily, a more compact coil design would enable its placement inside high field magnets (13).
Data acquisition for in vivo MRI was conducted using a 9.4T/160-mm animal MR system (Agilent Technologies, Santa Clara, CA, USA) with a 400 mT/m gradient. Renal sodium levels were quantified in normal mice based on the following parameters: gradient echo sequence, repetition time (TR)/TE, 100/2.
Na dual-tuned coils. However, further work such as modification of our RF coils is needed to improve their performance and apply advanced pulse sequences for fast imaging and high SNR. Although we applied sodium MR imaging with traditional RF coil and sequences, modified RF coils and advanced MR protocols might better facilitate animal and clinical studies of alterations in sodium concentration in various diseases (e.
대상 데이터
Proton-sodium RF coils (105.8 and 400 MHz at 9.4T) were developed for this study. Basic RF circuit components were attached to each loop.
성능/효과
In conclusion, we acquired sodium images of mouse kidney with significantly greater spatial resolution by using 1H/23Na dual-tuned coils. However, further work such as modification of our RF coils is needed to improve their performance and apply advanced pulse sequences for fast imaging and high SNR.
3d). Our results confirmed that our simply designed RF coils with a combination of a 1H-tuned coil and a 23Na-tuned coil had sufficient performance at 9.4T. This design can also be used to independently tune and match each loop to ensure optimal sensitivity.
후속연구
This design can also be used to independently tune and match each loop to ensure optimal sensitivity. Finally, our preliminary results provide a foundation for an improvement in the quality of in vivo sodium MR imaging through the development of advanced RF coils.
참고문헌 (17)
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