5153517 Surface resonator for a magnetic resonance imaging apparatus

Oppelt, Ralph; Duerr, Wilhelm; Siebold, Horst

doi:10.1016/0730-725x(93)90260-k

Cited by 3 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…RF surface coils comprising one linear current element [19,20], two crossing linear current elements (butterfly coil) [21], or two parallel linear current elements (figure-of-eight coil, FO8) [22] positioned in the central region of the coil have been reported. The FO8 and the butterfly coils are composed by two central current elements with arbitrarily shaped current return paths.…”

Section: Introductionmentioning

confidence: 99%

Versatile coil design and positioning of transverse-field RF surface coils for clinical 1.5-T MRI applications

Alfonsetti

Clementi

Iotti

et al. 2004

MAGMA

View full text Add to dashboard Cite

Clinical MRI/MRS applications require radio frequency (RF) surface coils positioned at an arbitrary angle alpha with respect to B(0). In these experimental conditions the standard circular loop (CL) coil, producing an axial RF field, shows a large signal loss in the central region of interest (ROI). We demonstrate that transverse-field figure-of-eight (FO8) RF surface coils design are not subject to the same amount of signal loss in the central ROI as loop coils when their orientations are changed. The 1.5-T CL and FO8 prototypes (diameter = 10 cm) were built on Plexiglas using copper strips (width = 4 mm, thickness = 100 mum). The two linear elements of the FO8 coil were 1 cm apart. Axial spoiled gradient echo (SPGR) images of a phantom containing doped water were acquired with the coil plane at alpha=0 degrees , 45 degrees , and 90 degrees . As alpha increases, the CL images show, in the central ROI, a signal that decreases from a maximum value to zero. Whereas the FO8 images show, in the same ROI, a signal that varies little from the maximum value (20%). Optimized FO8 coils can be oriented with the coil plane positioned along any direction with respect to B(0) without significant signal loss. Transverse RF coil design should be useful for clinical MRS studies and also for parallel imaging techniques where versatile RF coils disposed along arbitrary directions are required.

show abstract

Section: Introductionmentioning

confidence: 99%

Versatile coil design and positioning of transverse-field RF surface coils for clinical 1.5-T MRI applications

Alfonsetti

Clementi

Iotti

et al. 2004

MAGMA

View full text Add to dashboard Cite

show abstract

“…It has been shown [28,29] that the transverse field circular FO8 coil, consisting of two parallel linear elements, exhibits a maximum B 1 field intensity at a specific location along the coil z-axis, as compared to the standard axial field circular loop (CL) coil. It is worth noting that in the literature there is some confusion about the naming of FO8 and Butterfly coils [20][21][22][23][24][25][26][27][28]. In previous work [30], we have adopted a clear denomination based on the geometrical disposition of the linear current elements that produce a specific B 1 field distribution.…”

Section: Introductionmentioning

confidence: 99%

“…The simplest, and most used, RF surface coil design consists of a circular or rectangular loop, giving a B 1 field that in the central region of the coil is perpendicular to the coil plane (axial RF field) [4,[20][21][22][23]. This RF coil design is especially suitable for MRI systems with horizontal B 0 field and a great number of MRS/MRI pre-clinical and clinical applications have been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

A theoretical and experimental study on transverse field radio frequency surface coils

2010

View full text Add to dashboard Cite

“…Novel RF surface coil designs comprising one linear current element [9,10], two crossing linear current elements (butterfly coil) [11], or two parallel linear current elements (figure-of-eight coil, F08) [12][13][14][15][16] positioned in the central region of the coil were developed to overcome sensitivity and/or spatial selectivity limitations in a given ROI. These geometries are called transverse field RF surface coils, because the current flowing in the linear elements produce a B 1 field that, in the central region of the RF coil is, substantially, a transverse RF field (i.e.…”

Section: Introductionmentioning

confidence: 99%

Improved 1.5 T Magnetic Resonance Spectroscopy in the Human Calf with a Spatially Selective Radio Frequency Surface Coil

Alfonsetti¹,

Testa²,

Iotti³

et al. 2010

TOSPECJ

View full text Add to dashboard Cite

We describe the use of a transverse field RF surface coil that improves 1.5 T proton MR spectroscopy in the human calf. A 2-element figure-of-eight (FO8) transverse field RF surface coil (diameter 2R=10 cm; separation between the two linear current elements 2s=1cm) and a circular loop (CL) coil of equal diameter where built and tested with proton PRESS spectra at 1.5 T. The 1 H PRESS spectra obtained in the resting calf muscle of healthy volunteers showed that the FO8 coil allows a higher PRESS SNR (up to a factor 4.5) within a region of about 20 mm centred at about 12 mm from the coil plane, as compared to a standard CL coil. We found also a faster PRESS SNR decrease in the muscle tissue for anterior/posterior distance >20 mm using the FO8 coil. The measured PRESS SNR in the fat tissues of the calf showed a signal mostly localised within 10 mm from the coils surface and with an improved SNR (up to 5.5 times) observed in the presence of the FO8 coil as compared to the CL coil of equal diameter. The FO8 coil design can be advantageous for MRS applications, since it allows higher SNR from a small VOI positioned centrally within a relatively narrow region at a given depth in the human calf. The reported spatial SNR features of the FO8 coil design should also be useful for 1 H and 31 P MRS metabolites quantification in the human brain.

show abstract

5153517 Surface resonator for a magnetic resonance imaging apparatus

Cited by 3 publications

References 0 publications

Versatile coil design and positioning of transverse-field RF surface coils for clinical 1.5-T MRI applications

Versatile coil design and positioning of transverse-field RF surface coils for clinical 1.5-T MRI applications

A theoretical and experimental study on transverse field radio frequency surface coils

Improved 1.5 T Magnetic Resonance Spectroscopy in the Human Calf with a Spatially Selective Radio Frequency Surface Coil

Contact Info

Product

Resources

About