Radiofrequency planar surface coil for magnetic resonance: When the use of a circular wire gives a noticeable advantage with respect to a flat strip conductor?

The aim of this study was to evaluate the potential of a miniaturized implantable nuclear magnetic resonance (NMR) coil to acquire in vivo proton NMR spectra in sub-microliter regions of interest and to obtain metabolic information using magnetic resonance spectroscopy (MRS) in these small volumes. For this purpose, the NMR microcoils were implanted in the right cortex of healthy rats and in C6 glioma-bearing rats. The dimensions of the microcoil were 450 micrometers wide and 3 mm long. The MRS acquisitions were performed at 7 Tesla using volume coil for RF excitation and microcoil for signal reception. The detection volume of the microcoil was measured equal to 450 nL. A gain in sensitivity equal to 76 was found in favor of implanted microcoil as compared to external surface coil. Nine resonances from metabolites were assigned in the spectra acquired in healthy rats (n = 5) and in glioma-bearing rat (n = 1). The differences in relative amplitude of choline, lactate and creatine resonances observed in glioma-bearing animal were in agreement with published findings on this tumor model. In conclusion, the designed implantable microcoil is suitable for in vivo MRS and can be used for probing the metabolism in localized and very small regions of interest in a tumor.

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Magnetic resonance imaging (1H) and spectroscopy (1H, 31P) of growing chicken embryos

Canadian Journal of Animal Science ◽

10.4141/cjas93-096 ◽

1993 ◽

Vol 73 (4) ◽

pp. 953-965 ◽

Cited By ~ 2

Author(s):

A. Lirette ◽

Z. Liu ◽

D. C. Crober ◽

R. A. Towner ◽

U. M. Oehler ◽

...

Keyword(s):

Nmr Spectroscopy ◽

Magnetic Resonance ◽

Nmr Spectra ◽

Surface Coil ◽

Nmr Imaging ◽

Chicken Embryos ◽

H Nmr ◽

Imaging And Spectroscopy ◽

Two Peaks

Nuclear magnetic resonance (NMR) imaging and spectroscopy techniques were used to observe in vivo anatomical and metabolite changes, respectively, in developing chicken embryos. Proton (1H) NMR images of the eggs revealed major changes in yolk shape from day 2 to day 6. Embryos were visible from day 6 to hatching, and good embryonic anatomical images were obtained. Two peaks were observed from 1H-NMR spectroscopy of fertilized eggs: one for lipid methylene protons, and one for water protons. Water peak to lipid peak ratios did not vary significantly (P > 0.05) from day 2 to day 21 of incubation. Localized 31P-NMR spectra of developing embryos were obtained with either a 31P surface coil or a double-tuned 31P/1H volume coil. The surface-coil method gave a greater signal to noise ratio by a factor of four. The 31P-NMR spectra indicated two peaks at day 2; these were attributed to phosphomonoesters and phosphodiesters. The three peaks characteristic of ATP appeared on day 11 and increased in size until hatching. From day 19, phosphocreatine was detectable. There appeared to be a good correlation between 31P-metabolite changes detected by in vivo 31P-NMR spectroscopy and literature values for biochemical analyses of developing chicken embryos. The advantage in using NMR imaging and spectroscopy techniques is that anatomical and metabolic changes can be obtained in vivo, non-invasively and repeatedly as an embryo develops. Key words: NMR, MRI, embryo, poultry

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Magnetic Resonance Imaging of Spinal Cord Disease of Childhood

PEDIATRICS ◽

10.1542/peds.78.2.251 ◽

1986 ◽

Vol 78 (2) ◽

pp. 251-256

Author(s):

Roger J. Packer ◽

Robert A. Zimmerman ◽

Leslie N. Sutton ◽

Larissa T. Bilaniuk ◽

Derek A. Bruce ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Spinal Cord ◽

Magnetic Resonance ◽

Vertebral Body ◽

Congenital Anomalies ◽

Correct Diagnosis ◽

Surface Coil ◽

Resonance Imaging ◽

Spinal Cord Disease ◽

Magnetic Resonance Imaging Mri

Correct diagnosis of spinal cord disease in childhood is often delayed, resulting in irreversible neurologic deficits. A major reason for this delay is the lack of a reliable means to noninvasively visualize the spinal cord. Magnetic resonance imaging (MRI) should be useful in the evaluation of diseases of the spinal cord. A 1.5 Tesla MRI unit with a surface coil was used to study 41 children, including eight patients with intrinsic spinal cord lesions, eight patients with masses compressing the cord, 12 patients with congenital anomalies of the cord or surrounding bony structures, three patients with syrinxes, and three patients with vertebral body abnormalities. Intrinsic lesions of the cord were well seen in all cases as intrinsic irregularly widened, abnormally intense cord regions. MRI was helpful in following the course of disease in patients with primary spinal cord tumors. Areas of tumor were separable from syrinx cavities. Extrinsic lesions compressing the cord and vertebral body disease were also well visualized. Congenital anomalies of the spinal cord, including tethering and lipomatous tissue, were better seen on MRI than by any other radiographic technique. MRI is an excellent noninvasive "screening" technique for children with suspected spinal cord disease and may be the only study needed in many patients with congenital spinal cord anomalies. It is also an excellent means to diagnose and follow patients with other forms of intra- and extraspinal pathology.

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Applicability of Magnetic Resonance Imaging in the Assessment of Fetal Urinary Tract Malformations

Canadian Association of Radiologists Journal ◽

10.1016/j.carj.2018.10.006 ◽

2019 ◽

Vol 70 (1) ◽

pp. 83-95 ◽

Cited By ~ 2

Author(s):

Tatiana Mendonça Fazecas ◽

Edward Araujo Júnior ◽

Heron Werner ◽

Pedro Daltro ◽

Alberto Borges Peixoto ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Urinary Tract ◽

Magnetic Resonance ◽

Three Dimensional ◽

Surface Coil ◽

Resonance Imaging ◽

Magnetic Resonance Imaging Mri ◽

Urinary Tract Malformations ◽

Weighted Sequences ◽

Urinary Tract Anomalies

Objective To assess the applicability of magnetic resonance imaging (MRI) to complement ultrasound in the diagnosis of fetal urinary tract anomalies. Methods This was a retrospective cohort study that included 41 women between 19 weeks and 37 weeks and 6 days of gestation carrying fetuses with malformations of the urinary tract which were initially diagnosed by ultrasound and then referred for MRI. In all cases, the diagnosis was confirmed after birth either through imaging or autopsy. A surface coil was positioned over the abdomen and T2-weighted sequences were obtained in the axial, coronal, and sagittal planes; T1 in at least one plane; and three-dimensional (3-D) TRUFI in fetuses with dilatation of the urinary tract. Results Mean gestational age at the time of MRI examination was 28.21 weeks. The rapid T2 sequences allowed all the anomalies of the fetal urinary tract to be assessed, whereas 3-D TRUFI sequencing proved very useful in evaluating anomalies involving dilatation of the urinary tract. The signs of pulmonary hypoplasia characterized by hypointense signal in the T2-weighted sequences were identified in 13 of the 41 fetuses. Conclusion MRI confirmed and added information to the ultrasound regarding fetal urinary tract anomalies, as well as information related to the other associated malformations, their progress in the prenatal period, and possible postnatal prognosis.

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Magnetic resonance imaging of cervical carcinoma using an endorectal surface coil

European Journal of Radiology ◽

10.1016/j.ejrad.2014.02.011 ◽

2014 ◽

Vol 83 (7) ◽

pp. 1030-1035 ◽

Cited By ~ 3

Author(s):

Kerstin A. Brocker ◽

Céline D. Alt ◽

Gerhard Gebauer ◽

Christof Sohn ◽

Peter Hallscheidt

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Cervical Carcinoma ◽

Surface Coil ◽

Resonance Imaging ◽

Endorectal Surface Coil

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Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game?

PLoS ONE ◽

10.1371/journal.pone.0161863 ◽

2016 ◽

Vol 11 (9) ◽

pp. e0161863 ◽

Cited By ~ 11

Author(s):

Oliver Weinberger ◽

Lukas Winter ◽

Matthias A. Dieringer ◽

Antje Els ◽

Celal Oezerdem ◽

...

Keyword(s):

Cardiac Magnetic Resonance ◽

Magnetic Resonance ◽

Surface Coil ◽

3 Tesla ◽

Rf Coil

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Retino-thalamo-cortical and callosal connections visualized with manganese-enhanced magnetic resonance imaging and validated with tract tracing techniques

10.14293/s2199-1006.1.sor-.ppfbvat.v1 ◽

2020 ◽

Author(s):

Robyn J. Laing ◽

Donna J Cross ◽

Jaime Olavarria

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Longitudinal Studies ◽

Ocular Dominance ◽

Surface Coil ◽

Resonance Imaging ◽

Adult Rats ◽

Callosal Connections ◽

Plastic Changes

Ocular dominance columns correlate with patchy callosal connections in Long Evans rats (Laing et al., 2015). We explored in vivo manganese-enhanced magnetic resonance imaging (MEMRI) as a possible strategy for longitudinal studies of plastic changes in the retino-thalamo-cortical and callosal pathways. MnCl 2 was injected either intraocularly or intracortically to label these pathways, respectively. The transport of the paramagnetic ion Mn 2+ was evaluated by comparing images acquired both before and 36 or 12 hours after intraocular or cortical injections, respectively. Images were acquired on a 3T magnet (Philips Achieva, Philips Healthcare, Andover, MA), using a custom surface coil and a T1-weighted MPRAGE image sequence (TR/TE = 23/11 ms; Ti=1000 ms; FA= 10 deg acquired matrix 432x432 mm over 118 slices, voxel size 0.11x0.11x0.2 mm 3 ). To validate the transport of Mn 2+ , each animal also received either an intraocular injection of the transneuronal tracer WGA-HRP, or cortical injections of HRP. Following monocular injections of MnCl 2 , MRI images showed significant, bilateral accumulations of Mn 2+ in regions of the SC, LGN and visual cortex that corresponded with regions labeled with HRP. In adult rats monocularly enucleated at birth, we injected MnCl 2 in the hemisphere contralateral to the remaining eye in an attempt to detect anomalies reported previously in the callosal pattern ipsilateral to the remaining eye. After the scans, the hemisphere injected with MnCl 2 was injected with HRP. MRI images revealed Mn 2+ patterns that closely resembled the callosal patterns demonstrated with HRP in the same animal. Our results suggest that both transneuronal retino-thalamo-cortical, as well as cortico-cortical transport of Mn 2+ provide potentially useful strategies for longitudinal studies of plastic changes in these pathways.

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