Abstract
In 19F-MRI studies limiting factors are the presence of a low signal due to the low concentration of 19F-nuclei, necessary for biological applications, and the inherent low sensitivity of MRI. Hence, acquiring images using the pulse sequence with the best signal to noise ratio (SNR) by optimizing the acquisition parameters specifically to a 19F compound is a core issue. In 19F-MRI, multiple-spin-echo (RARE) and gradient-echo (GRE) are the two most frequently used pulse sequence families; therefore we performed an optimization study of GRE pulse sequences based on numerical simulations and experimental acquisitions on fluorinated compounds. We compared GRE performance to an optimized RARE sequence. Images were acquired on a 7T MRI preclinical scanner on phantoms containing different fluorinated compounds. Actual relaxation times (T1, T2, T2) were evaluated in order to predict SNR dependence on sequence parameters. Experimental comparisons between spoiled GRE and RARE, obtained at a fixed acquisition time and in steady state condition, showed RARE sequence outperforming the spoiled GRE (up to 406% higher). Conversely, the use of the unbalanced-SSFP showed a significant increase in SNR compared to RARE (up to 28% higher). Moreover, this sequence (as GRE in general) was confirmed to be virtually insensitive to T1 and T2 relaxation times, after proper optimization, thus improving marker independence from the biological environment. These results confirm the efficacy of the proposed optimization tool and foster further investigation addressing in-vivo applicability.
| Original language | English |
|---|---|
| Title of host publication | Progress in Biomedical Optics and Imaging - Proceedings of SPIE |
| Publisher | SPIE |
| Volume | 9033 |
| ISBN (Print) | 9780819498267 |
| DOIs | |
| Publication status | Published - 2014 |
| Event | Medical Imaging 2014: Physics of Medical Imaging - San Diego, CA, United States Duration: Feb 17 2014 → Feb 20 2014 |
Other
| Other | Medical Imaging 2014: Physics of Medical Imaging |
|---|---|
| Country | United States |
| City | San Diego, CA |
| Period | 2/17/14 → 2/20/14 |
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Keywords
- Gradient Echo
- RARE
- sequence optimization
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Radiology Nuclear Medicine and imaging
Cite this
Comparison between optimized GRE and RARE sequences for 19F MRI studies. / Soffientini, Chiara D.; Mastropietro, Alfonso; Caffini, Matteo; Cocco, Sara; Zucca, Ileana; Scotti, Alessandro; Baselli, Giuseppe; Bruzzone, Maria Grazia.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 9033 SPIE, 2014. 90334E.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Comparison between optimized GRE and RARE sequences for 19F MRI studies
AU - Soffientini, Chiara D.
AU - Mastropietro, Alfonso
AU - Caffini, Matteo
AU - Cocco, Sara
AU - Zucca, Ileana
AU - Scotti, Alessandro
AU - Baselli, Giuseppe
AU - Bruzzone, Maria Grazia
PY - 2014
Y1 - 2014
N2 - In 19F-MRI studies limiting factors are the presence of a low signal due to the low concentration of 19F-nuclei, necessary for biological applications, and the inherent low sensitivity of MRI. Hence, acquiring images using the pulse sequence with the best signal to noise ratio (SNR) by optimizing the acquisition parameters specifically to a 19F compound is a core issue. In 19F-MRI, multiple-spin-echo (RARE) and gradient-echo (GRE) are the two most frequently used pulse sequence families; therefore we performed an optimization study of GRE pulse sequences based on numerical simulations and experimental acquisitions on fluorinated compounds. We compared GRE performance to an optimized RARE sequence. Images were acquired on a 7T MRI preclinical scanner on phantoms containing different fluorinated compounds. Actual relaxation times (T1, T2, T2) were evaluated in order to predict SNR dependence on sequence parameters. Experimental comparisons between spoiled GRE and RARE, obtained at a fixed acquisition time and in steady state condition, showed RARE sequence outperforming the spoiled GRE (up to 406% higher). Conversely, the use of the unbalanced-SSFP showed a significant increase in SNR compared to RARE (up to 28% higher). Moreover, this sequence (as GRE in general) was confirmed to be virtually insensitive to T1 and T2 relaxation times, after proper optimization, thus improving marker independence from the biological environment. These results confirm the efficacy of the proposed optimization tool and foster further investigation addressing in-vivo applicability.
AB - In 19F-MRI studies limiting factors are the presence of a low signal due to the low concentration of 19F-nuclei, necessary for biological applications, and the inherent low sensitivity of MRI. Hence, acquiring images using the pulse sequence with the best signal to noise ratio (SNR) by optimizing the acquisition parameters specifically to a 19F compound is a core issue. In 19F-MRI, multiple-spin-echo (RARE) and gradient-echo (GRE) are the two most frequently used pulse sequence families; therefore we performed an optimization study of GRE pulse sequences based on numerical simulations and experimental acquisitions on fluorinated compounds. We compared GRE performance to an optimized RARE sequence. Images were acquired on a 7T MRI preclinical scanner on phantoms containing different fluorinated compounds. Actual relaxation times (T1, T2, T2) were evaluated in order to predict SNR dependence on sequence parameters. Experimental comparisons between spoiled GRE and RARE, obtained at a fixed acquisition time and in steady state condition, showed RARE sequence outperforming the spoiled GRE (up to 406% higher). Conversely, the use of the unbalanced-SSFP showed a significant increase in SNR compared to RARE (up to 28% higher). Moreover, this sequence (as GRE in general) was confirmed to be virtually insensitive to T1 and T2 relaxation times, after proper optimization, thus improving marker independence from the biological environment. These results confirm the efficacy of the proposed optimization tool and foster further investigation addressing in-vivo applicability.
KW - Gradient Echo
KW - RARE
KW - sequence optimization
UR - http://www.scopus.com/inward/record.url?scp=84901594064&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901594064&partnerID=8YFLogxK
U2 - 10.1117/12.2042658
DO - 10.1117/12.2042658
M3 - Conference contribution
SN - 9780819498267
VL - 9033
BT - Progress in Biomedical Optics and Imaging - Proceedings of SPIE
PB - SPIE
ER -