scholarly journals Development of a Proton-Frequency-Transparent Birdcage Radiofrequency Coil for In Vivo 13C MRS/MRSI Study in a 3.0 T MRI System

2021 ◽  
Vol 11 (23) ◽  
pp. 11445
Author(s):  
Jun-Sik Yoon ◽  
Jong-Min Kim ◽  
Han-Jae Chung ◽  
You-Jin Jeong ◽  
Gwang-Woo Jeong ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Corn Oil ◽  
Mr Studies ◽  
Rf Coil ◽  
Mr Images ◽  
Hyperpolarized 13C ◽  
3.0 T ◽  
13C Mrs ◽  
3.0 T Mri

A proton-frequency-transparent (PFT) birdcage RF coil that contains carbon-proton switching circuits (CPSCs) is presented to acquire 13C MR signals, which, in turn, enable 1H imaging with existing 1H RF coils without being affected by a transparent 13C birdcage RF coil. CPSCs were installed in the PFT 13C birdcage RF coil to cut the RF coil circuits during 1H MR imaging. Finite-difference time-domain (FDTD) electromagnetic (EM) simulations were performed to verify the performance of the proposed CPSCs. The performance of the PFT 13C birdcage RF coil with CPSCs was verified via phantom and in vivo MR studies. In the phantom MR studies, 1H MR images and 13C MR spectra were acquired and compared with each other using the 13C birdcage RF coil with and without the CPSCs. For the in vivo MR studies, hyperpolarized 13C cardiac MRS and MRSI of swine were performed. The proposed PFT 13C birdcage RF coil with CPSCs led to a percent image uniformity (PIU) reduction of 1.53% in the proton MR images when compared with the case without it. FDTD EM simulations revealed PIU reduction of 0.06% under the same conditions as the phantom MR studies. Furthermore, an SNR reduction of 5.5% was observed at 13C MR spectra of corn-oil phantom using the PFT 13C birdcage RF coil with CPSCs compared with that of the 13C birdcage RF coil without CPSCs. Utilizing the PFT 13C birdcage RF coil, 13C-enriched compounds were successfully acquired via in vivo hyperpolarized 13C MRS/MRSI experiments. In conclusion, the applicability and utility of the proposed 16-leg low-pass PFT 13C birdcage RF coil with CPSCs were verified via 1H MR imaging and hyperpolarized 13C MRS/MRSI studies using a 3.0 T MRI system.

scholarly journals Evaluation of endometrial thickness in postmenopausal women by using 3.0-T MRI

2014 ◽  
Vol 18 (1) ◽  
Author(s):  
Junko Nakamura ◽  
Takeharu Yoshikawa ◽  
Eriko Maeda ◽  
Hiroyuki Akai ◽  
Hiroshi Ohtsu ◽  
...  
Keyword(s):  
Postmenopausal Women ◽  
Medical Records ◽  
Endometrial Thickness ◽  
Mr Images ◽  
Endometrial Thickening ◽  
3.0 T ◽  
The Mean ◽  
Magnetic Resonance Imaging Mri ◽  
3.0 T Mri

Background: The accepted threshold for normal endometrial thickness is 5 mm; lesions with endometrial thickness < 5 mm are considered benign, whilst those > 5 mm areconsidered malignant. However, endometrium ≥ 5 mm on transvaginal ultrasonography inpostmenopausal woman is considered as asymptomatic endometrial thickening. However, recent studies suggest that asymptomatic endometrial thickness of even 8 mm – 11 mm in postmenopausal women may be normal.Objectives: The present study investigated the normal endometrial thickness range in 297 asymptomatic postmenopausal women using 3.0-T magnetic resonance imaging (MRI) T2-weighted sagittal images measured retrospectively by a single radiologist.Method: The data were classified according to patient age and postmenopausal duration, and the medical records and follow-up MR images were reviewed to assess the clinical outcome.Results: The mean endometrial thickness was 2.4 ± 0.1 mm (range: 0.1–11.6). The endometriumin 21 of 297 subjects was ≥ 5 mm thick. Follow-up MR images were obtained in 17 of these 21 women, and their endometrial thickness was found to have decreased in all of them. To date,none of the subjects has been diagnosed with endometrial cancer.Conclusion: Although 5 mm is considered the conservative threshold of normal endometrial thickness on MRI of postmenopausal women, this figure should not, to avoid excessive false-positive diagnoses, be assumed as an indication of malignancy.

Usefulness of composite methionine–positron emission tomography/3.0-tesla magnetic resonance imaging to detect the localization and extent of early-stage Cushing adenoma

2010 ◽  
Vol 112 (4) ◽  
pp. 750-755 ◽  
Author(s):  
Hidetoshi Ikeda ◽  
Takehiko Abe ◽  
Kazuo Watanabe
Keyword(s):  
Mr Imaging ◽  
Diagnostic Accuracy ◽  
Fdg Pet ◽  
Early Stage ◽  
False Negative ◽  
Mr Images ◽  
Cushing Disease ◽  
Significant Difference ◽  
3.0 T ◽  
Met Pet

Object Fifty to eighty percent of Cushing disease is diagnosed by typical endocrine responses. Recently, the number of diagnoses of Cushing disease without typical Cushing syndrome has been increasing; therefore, improving ways to determine the localization of the adenoma and making an early diagnosis is important. This study was undertaken to determine the present diagnostic accuracy for Cushing microadenoma and to compare the differences in diagnostic accuracy between MR imaging and PET/MR imaging. Methods During the past 3 years the authors analyzed the diagnostic accuracy in a series of 35 patients with Cushing adenoma that was verified by surgical pituitary exploration. All 35 cases of Cushing disease, including 20 cases of “overt” and 15 cases of “preclinical” Cushing disease, were studied. Superconductive MR images (1.5 or 3.0 T) and composite images from FDG-PET or methionine (MET)–PET and 3.0-T MR imaging were compared with the localization of adenomas verified by surgery. Results The diagnostic accuracy of superconductive MR imaging for detecting the localization of Cushing microadenoma was only 40%. The causes of unsatisfactory results for superconductive MR imaging were false-negative results (10 cases), false-positive results (6 cases), and instances of double pituitary adenomas (3 cases). In contrast, the accuracy of microadenoma localization using MET-PET/3.0-T MR imaging was 100% and that of FDG-PET/3.0-T MR imaging was 73%. Moreover, the adenoma location was better delineated on MET-PET/MR images than on FDG-PET/MR images. There was no significant difference in maximum standard uptake value of adenomas evaluated by MET-PET between preclinical Cushing disease and overt Cushing disease. Conclusions Composite MET-PET/3.0-T MR imaging is useful for the improvement of the delineation of Cushing microadenoma and offers high-quality detectability for early-stage Cushing adenoma.

Adjustable shunt valve–induced magnetic resonance imaging artifact: a comparative study

2010 ◽  
Vol 113 (1) ◽  
pp. 74-78 ◽  
Author(s):  
Ahmed K. Toma ◽  
Andrew Tarnaris ◽  
Joan P. Grieve ◽  
Laurence D. Watkins ◽  
Neil D. Kitchen
Keyword(s):  
Mr Imaging ◽  
Pulse Sequence ◽  
Spin Echo ◽  
Pulse Sequences ◽  
Fast Spin Echo ◽  
Mr Images ◽  
Shunt Valve ◽  
Adjustable Valve ◽  
Imaging Artifact

Object In this paper, the authors' goal was to compare the artifact induced by implanted (in vivo) adjustable shunt valves in spin echo, diffusion weighted (DW), and gradient echo MR imaging pulse sequences. Methods The MR images obtained in 8 patients with proGAV and 6 patients with Strata II adjustable shunt valves were assessed for artifact areas in different planes as well as the total volume for different pulse sequences. Results Artifacts induced by the Strata II valve were significantly larger than those induced by proGAV valve in spin echo MR imaging pulse sequence (29,761 vs 2450 mm3 on T2-weighted fast spin echo, p = 0.003) and DW images (100,138 vs 38,955 mm3, p = 0.025). Artifacts were more marked on DW MR images than on spin echo pulse sequencse for both valve types. Conclusions Adjustable valve–induced artifacts can conceal brain pathology on MR images. This should influence the choice of valve implantation site and the type of valve used. The effect of artifacts on DW images should be highlighted pending the development of less MR imaging artifact–inducing adjustable shunt valves.

In vivo 39K, 23Na and 1H MR imaging using a triple resonant RF coil setup

2009 ◽  
Vol 200 (1) ◽  
pp. 134-136 ◽  
Author(s):  
Mark Augath ◽  
Patrick Heiler ◽  
Stefan Kirsch ◽  
Lothar R. Schad
Keyword(s):  
Mr Imaging ◽  
Rf Coil

Diagnostic accuracy of DW MR imaging in the differentiation of chordomas and chondrosarcomas of the skull base: A 3.0-T MRI study of 105 cases

2018 ◽  
Vol 105 ◽  
pp. 119-124 ◽  
Author(s):  
Thomas Welzel ◽  
Eva Meyerhof ◽  
Matthias Uhl ◽  
Kristin Huang ◽  
Andreas von Deimling ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Diagnostic Accuracy ◽  
Skull Base ◽  
3.0 T ◽  
Mri Study ◽  
3.0 T Mri

scholarly journals Thermoacoustic tomography of in vivo rat brain

2017 ◽  
Vol 10 (04) ◽  
pp. 1740001 ◽  
Author(s):  
Yuan Zhao ◽  
Zihui Chi ◽  
Lin Huang ◽  
Zhu Zheng ◽  
Jinge Yang ◽  
...  
Keyword(s):  
Rat Brain ◽  
In Vivo Imaging ◽  
Thermoacoustic Tomography ◽  
Anatomical Structures ◽  
3.0 T ◽  
Electric Field Polarization ◽  
First Time ◽  
The Brain ◽  
3.0 T Mri

We present for the first time in vivo imaging of rat brain using microwave-induced thermoacoustic tomography (TAT). The in vivo imaging of rat brain was realized through an unconventional delivery of microwave energy from the front of rat brain (while the transducer was scanned along coronal plane of the animal brain), which maximized the microwave penetration into the brain. In addition, we found that the imaging contrast was highly dependent on the direction of the electric field polarization (EFP) and that more tissue structures/compositions could be revealed when both [Formula: see text]- and [Formula: see text]-EFPs were used for TAT. The in vivo TAT images of rat brain obtained were compared with the 3.0 T MRI images and histological photographs, and numerous important brain anatomical structures were identified. An example of our TAT approach for imaging a foreign object embedded in a rat brain was also demonstrated. This study suggests that TAT has a great potential to be used in neuroscience studies and in noninvasive imaging of brain disorders.

scholarly journals Synthesis, Characterizations, and 9.4 Tesla T2 MR Images of Polyacrylic Acid-Coated Terbium(III) and Holmium(III) Oxide Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1355
Author(s):  
Shanti Marasini ◽  
Huan Yue ◽  
Son Long Ho ◽  
Ji Ae Park ◽  
Soyeon Kim ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Polyacrylic Acid ◽  
Colloidal Stability ◽  
Negative Contrast ◽  
Mri Contrast Agents ◽  
Mr Images ◽  
Mri Contrast ◽  
3.0 T ◽  
Magnetic Resonance Imaging Mri

Polyacrylic acid (PAA)-coated lanthanide oxide (Ln2O3) nanoparticles (NPs) (Ln = Tb and Ho) with high colloidal stability and good biocompatibility were synthesized, characterized, and investigated as a new class of negative (T2) magnetic resonance imaging (MRI) contrast agents at high MR fields. Their r2 values were appreciable at a 3.0 T MR field and higher at a 9.4 T MR field, whereas their r1 values were negligible at all MR fields, indicating their exclusive induction of T2 relaxations with negligible induction of T1 relaxations. Their effectiveness as T2 MRI contrast agents at high MR fields was confirmed from strong negative contrast enhancements in in vivo T2 MR images at a 9.4 T MR field after intravenous administration into mice tails.

scholarly journals Noninvasive in Vivo Tracking of Mesenchymal Stem Cells and Evaluation of Cell Therapeutic Effects in a Murine Model Using a Clinical 3.0 T MRI

2013 ◽  
Vol 22 (11) ◽  
pp. 1971-1980 ◽  
Author(s):  
Florian Drey ◽  
Yeong-Hoon Choi ◽  
Klaus Neef ◽  
Birgit Ewert ◽  
Arne Tenbrock ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Murine Model ◽  
Therapeutic Effects ◽  
3.0 T ◽  
3.0 T Mri

scholarly journals Uniform Fe3O4/Gd2O3-DHCA nanocubes for dual-mode MR imaging

2020 ◽  
Author(s):  
Miao Qin ◽  
Yueyou Peng ◽  
Mengjie Xu ◽  
Hui Yan ◽  
Yizhu Cheng ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Clinical Diagnosis ◽  
Multimodal Imaging ◽  
Experimental Results ◽  
Dual Mode ◽  
3.0 T

Multimodal imaging technology were extensively studied over past few years, because they offered complementary diagnosis information, which can increase the accuracy of diagnosis. The synthesis of contrast agents via simplified methods are desired for the development of multimodal imaging. Herein, uniformly distributed Fe3O4/Gd2O3 nanocubes for T1-T2 dual-mode contrast agents were rationally designed and successfully fabricated by our group. In this system, the Fe3O4/Gd2O3 nanocubes were coated with nontoxic 3,4-dihydroxyhydrocinnamic acid (DHCA) for better hydrophilia and biocompatibility. The results show that Ferrum (Fe) and Gadolinium (Gd) elements are homo-dispersity in the Fe3O4/Gd2O3-DHCA (FGDA) nanocubes. Relaxivity study at 3.0 T scanner demonstrates that the r1 value and r2 value of FGDA nanocubes reach up to 67.57 ± 6.2 mM-1s-1 and 24.2 ± 1.46 mM-1s-1. The images of T1-weighted and T2-weighted imaging in vivo demonstrate that FGDA nanocubes possess the ability of magnetic resonance (MR) imaging enhancement as dual-mode contrast agent. The above illustrated experimental results indicate that FGDA nanocubes can be applied in clinical diagnosis in future.

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