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Gradient‐echo and spin‐echo blood oxygenation level–dependent functional MRI at ultrahigh fields of 9.4 and 15.2 Tesla
| Content Provider | Scilit |
|---|---|
| Author | Han, Sohyun Son, Jeong Pyo Cho, Hyungjoon Park, Jang‐Yeon Kim, Seong‐Gi |
| Copyright Year | 2018 |
| Description | Journal: Magnetic Resonance in Medicine Purpose Sensitivity and specificity of blood oxygenation level–dependent (BOLD) functional MRI (fMRI) is sensitive to magnetic field strength and acquisition methods. We have investigated gradient‐echo (GE)‐ and spin‐echo (SE)‐BOLD fMRI at ultrahigh fields of 9.4 and 15.2 Tesla. Methods BOLD fMRI experiments responding to forepaw stimulation were performed with 3 echo times (TE) at each echo type and $B_{0}$ in α‐chloralose–anesthetized rats. The contralateral forelimb somatosensory region was selected for quantitative analyses. Results At 9.4 T and 15.2 T, average baseline T_{2}$^{*}$ (n = 9) was 26.6 and 17.1 msec, whereas baseline $T_{2 }$value (n = 9) was 35.7 and 24.5 msec, respectively. Averaged stimulation‐induced ΔR_{2}$^{*}$ was –1.72 $s^{–1}$ at 9.4 T and –3.09 $s^{–1}$ at 15.2 T, whereas $ΔR_{2}$ was –1.19 $s^{–1}$ at 9.4 T and –1.97 $s^{–1}$ at 15.2 T. At the optimal TE of tissue T_{2}$^{*}$ or $T_{2}$, BOLD percent changes were slightly higher at 15.2 T than at 9.4 T (GE: 7.4% versus 6.4% and SE: 5.7% versus 5.4%). The ΔR_{2}$^{*}$ and $ΔR_{2}$ ratio of 15.2 T to 9.4 T was 1.8 and 1.66, respectively. The ratio of the macrovessel‐containing superficial to microvessel‐dominant parenchymal BOLD signal was 1.73 to 1.76 for GE‐BOLD versus 1.13 to 1.19 for SE‐BOLD, indicating that the SE‐BOLD contrast is less sensitive to macrovessels than GE‐BOLD. Conclusion SE‐BOLD fMRI improves spatial specificity to microvessels compared to GE‐BOLD at both fields. BOLD sensitivity is similar at the both fields and can be improved at ultrahigh fields only for thermal‐noise–dominant ultrahigh‐resolution fMRI. |
| Related Links | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6585650/pdf |
| Ending Page | 1246 |
| Page Count | 10 |
| Starting Page | 1237 |
| e-ISSN | 15222594 |
| DOI | 10.1002/mrm.27457 |
| Journal | Magnetic Resonance in Medicine |
| Issue Number | 2 |
| Volume Number | 81 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 2019-02-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: Magnetic Resonance in Medicine Radiology, Nuclear Medicine and Imaging |
| Content Type | Text |
| Resource Type | Article |
