Standard 3.0 T MR Imaging

Scarabino, Tommaso; Nemore, F.; Giannatempo, G.M.; Simeone, Annalisa; Maggialetti, A.; Maggialetti, Nicola; Salvolini, U.

doi:10.1007/3-540-31776-7_4

Cited by 3 publications

(4 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dose can even be halved without compromising the sensitivity of the intensity/time curves from which the rCBV and MTT values are subsequently deduced. A standard dose of contrast medium is not necessary for perfusion studies using 3.0 T MR systems [1][2][3][4] , and the dose can be further reduced by administering a higher concentration (1 molar) (figure 7).…”

Section: Perfusion At 30 Tmentioning

confidence: 98%

See 1 more Smart Citation

3.0 T Perfusion MR Imaging

Scarabino¹,

Giannatempo

Pollice³

et al. 2004

Rivista di Neuroradiologia

Self Cite

View full text Add to dashboard Cite

Section: Perfusion At 30 Tmentioning

confidence: 98%

“…Using EPI sequences and a borderline S/N, perfusion MR imaging gains from high magnetic field strength [1][2][3][4][5] . ASL is improved by the increased T1 and higher S/N 6 , as is DSC by virtue of the higher S/N and enhanced magnetic susceptibility.…”

Section: Perfusion At 30 Tmentioning

confidence: 99%

3.0 T Perfusion MR Imaging

Scarabino¹,

Giannatempo

Pollice³

et al. 2004

Rivista di Neuroradiologia

Self Cite

View full text Add to dashboard Cite

“…The well-known areas of the white matter, namely the periventricular areas physiologi-cally hyperintense in lower field (1.5 T) images, are even more pronounced in 3.0 T images so that special attention is required to distinguish them from diseases like amyotrophic lateral sclerosis 4 . The semeiological features described for the grey nuclei and recent bleeds also apply to FLAIR sequences 3-10 ( figure 12).…”

Section: Flair Imagingmentioning

confidence: 99%

3.0 T MR Imaging

Scarabino

Nemore²,

Giannatempo³

et al. 2004

Rivista di Neuroradiologia

Self Cite

View full text Add to dashboard Cite

Impulse SequencesA 3.0 T MR system implements all the impulse sequences usually applied in clinical practice such as spin echo (SE): normal, fast 2D and 3D; gradient echo (GE): GRASS / Fast-GRASS 2D and 3D, SPGR / Fast SPGR 2D e 3D; echoplanar (EPI): single shot / multishot 2D e 3D; inversion recovery (IR): STIR, FLAIR (normal, fast), using the usual imaging parameters like flow and respiratory compensation, cardiac and peripheral gating, graphic prescription, fat/water saturation, variable bandwidth and asymmetric field of view.Both the user interface and the parameters of these sequences are the same as those of 1.5 T systems so that recompiling such sequences on 3.0 T systems should theoretically yield exactly the same images with the advantage of high field strength, namely a double signal intensity. In practice, much depends on the relaxation times (T1 and T2) and the SAR 1-3 . As

show abstract

“…At high magnetic field strength, spectroscopy improves with respect to lower field MR devices thanks to an increase in the signal/noise ratio (S/N) and resolution of the chemical shift (figure 3) [1][2][3][4][5][6][7] .…”

mentioning

confidence: 99%

3.0 T Proton MR Spectroscopy

Scarabino¹,

Nemore²,

Giannatempo³

et al. 2004

Rivista di Neuroradiologia

Self Cite

View full text Add to dashboard Cite

Proton MR Spectroscopy at 3.0 T Increased S/N and chemical shiftAt high magnetic field strength, spectroscopy improves with respect to lower field MR devices thanks to an increase in the signal/noise ratio (S/N) and resolution of the chemical shift (figure 3) 1-7 .In theory, the S/N should double on moving from 1.5 T to 3.0 T systems, but in practice the improvement is only around 20-46%. The linear rise in the S/N ratio expected with 3.0 T MR units would only be possible if other factors like T1 and T2 values (T1 is increased, T2 is decreased) or the RF effect failed to change significantly. To this should be added the lower coil sensitivity and poorer homogeneity of its volume, less shimming and misregistration errors caused by the wider chemical shift which can degrade the quality of the spectra 4-6 .In terms of increased resolution of the chemical shift, although the position of spectrum peaks is constant on the ppm scale (e.g. NAA at 2.02 ppm), the resonance frequency is different (for NAA 127 Hz at 1.5 T, 254 Hz at 3.0 T). The greater amplitude of the chemical shift frequency range of brain metabolites yields better spectral resolution and hence a more clear-cut separation between adjacent peaks which may overlap at lower magnetic field strength. In practice, this major advantage cannot be fully exploited in in vivo spectroscopy studies as the linewidth (in Hz) of the metabolites increases by at least a factor of two so that the separation between individual adjacent peaks is not radically improved using 3.0 T MR systems. The increase in linewidth is proportional to the reduction in T2 values and the increase in local magnetic field inhomogeneity at high field strength. Inhomogeneity can be reducing by more appropriate higher grade shimming. In addition, if the spatial dimensions of field inhomogeneities are within the range of voxel size, narrower linewidths can be obtained by using small voxels (less than 0.4 ml, i.e., 0.7×0.7×0.7 mmc) 8 . INTRODUCTION -Proton MR spectroscopy (MRS)consists in the in vivo study of some of the steps involved in brain metabolism. Proton MRS displays low molecular weight brain metabolites in the form of spectra whose shape basically depends on metabolite concentration (more than 0.1-1 mM) which varies in different pathological conditions. Proton MRS is an adjunct to routine MR investigation offering information useful for tissue characterization. The main metabolites detected vary according to the acquisition parameters (TR, TE) and type of impulse sequence adopted (STEAM, PRESS), and include: N-acetyl-aspartate (NAA, neuronal marker) at 2.01 ppm, choline (Cho, membrane marker) at 3.22 ppm, creatine/phosphocreatine (Cr/PCr, cell density index) at 3.5 ppm, myoinositol (mI, glial marker) at 3.56 ppm and when present lactic acid (Lac, anaerobic glycolysis index) and lipids (Lip, necrosis index). Two techniques, single voxel and multivoxel, are used depending on the spatial localisation procedure. Single voxel MRS acquires the spectrum of a preselected brain volume of interest, w...

show abstract

Standard 3.0 T MR Imaging

Cited by 3 publications

References 16 publications

3.0 T Perfusion MR Imaging

3.0 T Perfusion MR Imaging

3.0 T MR Imaging

3.0 T Proton MR Spectroscopy

Contact Info

Product

Resources

About