Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance

Pisa, Italy

Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance

Pisa, Italy

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Costagli M.,Imago7 Foundation | Costagli M.,Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance | Symms M.R.,GE Applied Science Laboratory | Angeli L.,University of Pisa | And 12 more authors.
European Radiology | Year: 2015

Objectives: This study aimed to assess the performance of a “Silent” zero time of echo (ZTE) sequence for T1-weighted brain imaging using a 7 T MRI system. Methods: The Silent sequence was evaluated qualitatively by two neuroradiologists, as well as quantitatively in terms of tissue contrast, homogeneity, signal-to-noise ratio (SNR) and acoustic noise. It was compared to conventional T1-weighted imaging (FSPGR). Adequacy for automated segmentation was evaluated in comparison with FSPGR acquired at 7 T and 1.5 T. Specific absorption rate (SAR) was also measured. Results: Tissue contrast and homogeneity in Silent were remarkable in deep brain structures and in the occipital and temporal lobes. Mean tissue contrast was significantly (p < 0.002) higher in Silent (0.25) than in FSPGR (0.11), which favoured automated tissue segmentation. On the other hand, Silent images had lower SNR with respect to conventional imaging: average SNR of FSPGR was 2.66 times that of Silent. Silent images were affected by artefacts related to projection reconstruction, which nevertheless did not compromise the depiction of brain tissues. Silent acquisition was 35 dB(A) quieter than FSPGR and less than 2.5 dB(A) louder than ambient noise. Six-minute average SAR was <2 W/kg. Conclusions: The ZTE Silent sequence provides high-contrast T1-weighted imaging with low acoustic noise at 7 T. Key Points: • “Silent” is an MRI technique allowing zero time of echo acquisition• Its feasibility and performance were assessed on a 7 T MRI system• Image quality in several regions was higher than in conventional techniques• Imaging acoustic noise was dramatically reduced compared with conventional imaging• “Silent” is suitable for T1-weighted head imaging at 7 T © 2015 European Society of Radiology


PubMed | University of Ferrara, Neuroradiology Unit, Imago7 Foundation, General Electric and 3 more.
Type: Journal Article | Journal: European radiology | Year: 2016

This study aimed to assess the performance of a Silent zero time of echo (ZTE) sequence for T1-weighted brain imaging using a 7T MRI system.The Silent sequence was evaluated qualitatively by two neuroradiologists, as well as quantitatively in terms of tissue contrast, homogeneity, signal-to-noise ratio (SNR) and acoustic noise. It was compared to conventional T1-weighted imaging (FSPGR). Adequacy for automated segmentation was evaluated in comparison with FSPGR acquired at 7T and 1.5T. Specific absorption rate (SAR) was also measured.Tissue contrast and homogeneity in Silent were remarkable in deep brain structures and in the occipital and temporal lobes. Mean tissue contrast was significantly (p<0.002) higher in Silent (0.25) than in FSPGR (0.11), which favoured automated tissue segmentation. On the other hand, Silent images had lower SNR with respect to conventional imaging: average SNR of FSPGR was 2.66 times that of Silent. Silent images were affected by artefacts related to projection reconstruction, which nevertheless did not compromise the depiction of brain tissues. Silent acquisition was 35dB(A) quieter than FSPGR and less than 2.5dB(A) louder than ambient noise. Six-minute average SAR was <2W/kg.The ZTE Silent sequence provides high-contrast T1-weighted imaging with low acoustic noise at 7T. Silent is an MRI technique allowing zero time of echo acquisition Its feasibility and performance were assessed on a 7T MRI system Image quality in several regions was higher than in conventional techniques Imaging acoustic noise was dramatically reduced compared with conventional imaging Silent is suitable for T1-weighted head imaging at 7T.


Costagli M.,Imago7 Research Foundation | Costagli M.,Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance | Donatelli G.,University of Pisa | Biagi L.,Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance | And 6 more authors.
NeuroImage: Clinical | Year: 2016

Amyotrophic Lateral Sclerosis (ALS) is a progressive neurological disorder that entails degeneration of both upper and lower motor neurons. The primary motor cortex (M1) in patients with upper motor neuron (UMN) impairment is pronouncedly hypointense in Magnetic Resonance (MR) T2* contrast. In the present study, 3D gradient-recalled multi-echo sequences were used on a 7. Tesla MR system to acquire T2*-weighted images targeting M1 at high spatial resolution. MR raw data were used for Quantitative Susceptibility Mapping (QSM). Measures of magnetic susceptibility correlated with the expected concentration of non-heme iron in different regions of the cerebral cortex in healthy subjects. In ALS patients, significant increases in magnetic susceptibility co-localized with the T2* hypointensity observed in the middle and deep layers of M1. The magnetic susceptibility, hence iron concentration, of the deep cortical layers of patients' M1 subregions corresponding to Penfield's areas of the hand and foot in both hemispheres significantly correlated with the clinical scores of UMN impairment of the corresponding limbs. QSM therefore reflects the presence of iron deposits related to neuroinflammatory reaction and cortical microgliosis, and might prove useful in estimating M1 iron concentration, as a possible radiological sign of severe UMN burden in ALS patients. © 2016 The Authors.


PubMed | Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance, University of Pisa and Imago7 Research Foundation
Type: | Journal: NeuroImage. Clinical | Year: 2016

Amyotrophic Lateral Sclerosis (ALS) is a progressive neurological disorder that entails degeneration of both upper and lower motor neurons. The primary motor cortex (M1) in patients with upper motor neuron (UMN) impairment is pronouncedly hypointense in Magnetic Resonance (MR) T2* contrast. In the present study, 3D gradient-recalled multi-echo sequences were used on a 7Tesla MR system to acquire T2*-weighted images targeting M1 at high spatial resolution. MR raw data were used for Quantitative Susceptibility Mapping (QSM). Measures of magnetic susceptibility correlated with the expected concentration of non-heme iron in different regions of the cerebral cortex in healthy subjects. In ALS patients, significant increases in magnetic susceptibility co-localized with the T2* hypointensity observed in the middle and deep layers of M1. The magnetic susceptibility, hence iron concentration, of the deep cortical layers of patients M1 subregions corresponding to Penfields areas of the hand and foot in both hemispheres significantly correlated with the clinical scores of UMN impairment of the corresponding limbs. QSM therefore reflects the presence of iron deposits related to neuroinflammatory reaction and cortical microgliosis, and might prove useful in estimating M1 iron concentration, as a possible radiological sign of severe UMN burden in ALS patients.

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