کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6268549 | 1614630 | 2015 | 13 صفحه PDF | دانلود رایگان |
- We transferred ultrahigh-resolution fMRI protocols to clinical 3Â T settings.
- Thereby, the maximal t-value in the sensorimotor cortex (SMC) was increased by 66%.
- Number of activated clusters in the SMC was increased by a factor of 3.3.
- In the nucleus accumbens, the cluster number increased with the proposed protocol.
BackgroundTo translate highly accelerated EPI-fMRI protocols as commonly used at ultra-high field strengths to clinical 3Â T settings.New methodEPI protocols with increasing matrix sizes and parallel imaging (PI) factors were tested in two separate fMRI studies, a simple motor-task and a complex motivation-task experiment with focus on the sensorimotor cortex (SMC) and the nucleus accumbens (NAcc), respectively.ResultsBy increasing the matrix size and the PI-factor simultaneously, BOLD-sensitivity in terms of maximal t-values and numbers of activated clusters was uncompromised in single individuals in both fMRI experiments. In the SMC, the multi-subject analysis revealed an increase of 66% of the maximal t-value whereby the number of activated clusters was increased by a factor of 3.3 when the matrix size (PI-factor) was increased from 96Â ÃÂ 96 (RÂ =Â 2) to 192Â ÃÂ 192 (RÂ =Â 4). In the NAcc, the number of activated clusters increased from 5 to 7 whereby the maximal t-value remained unaffected when the matrix size (PI-factor) was increased from 96Â ÃÂ 96 (RÂ =Â 2) to 160Â ÃÂ 160 (RÂ =Â 3).Comparison with existing methodUsing the proposed high-resolution EPI protocol, spatial blurring was clearly reduced. Further, BOLD sensitivity was clearly improved in multi-subject analyses and remained unaffected in single individuals compared to using the standard protocols.ConclusionsConventionally used matrix sizes (PI-factors) might be non-optimal for some applications sacrificing BOLD spatial specificity. We recommend using the proposed high-resolution protocols applicable in detecting robust BOLD activation in fMRI.
Journal: Journal of Neuroscience Methods - Volume 239, 15 January 2015, Pages 170-182