Faster brain imaging without expensive upgrades
Researchers developed a way to scan brain activity twice as quickly using standard MRI equipment, matching the detection power of slower scans. The breakthrough could let hospitals and research labs improve neuroimaging studies without replacing expensive hardware or retraining staff on new analysis methods.
Originaltitel: Increased fMRI Sensitivity at Equal Data Burden Using Averaged Shifted Echo Acquisition
**Kostnad-effektiv fMRI-avbildning möjlig med standard-utrustning** Forskare vid Linköpings universitet presenterar en metodutveckling som ökar känsligheten i hjärnaktivitetsmätningar utan att kräva dyr ny hårdvara. Genom att integrera "shifted echo"-teknik i vanlig magnetresonanstomografi kan man minska upptagningsintervallet (TR) till under 1 sekund samtidigt som datavolymen hålls hanterbar. Studien jämförde fyra olika inställningar på 11 försöksdeltagare. Den optimala metoden — där data genomsnittades två och två — visade 25–30 procent förbättrad signalkvalitet jämfört med referenssekvensen. Detta uppnåddes utan att öka datamängden nämnvärt. Resultatet är affärsmässigt relevant för kliniker och forskningscentra som saknar infrastruktur för experimentell avbildningsteknik. Metoden gör avancerad funktionell hjärnmappning tillgänglig på befintlig utrustning och minskar behovet av specialiserad support, vilket påverkar investeringsbeslut för stora medicinska institutioner.
<p>There is growing evidence as to the benefits of collecting BOLD fMRI data with increased sampling rates. However, many of the newly developed acquisition techniques developed to collect BOLD data with ultra-short TRs require hardware, software, and non-standard analytic pipelines that may not be accessible to all researchers. We propose to incorporate the method of shifted echo into a standard multi-slice, gradient echo EPI sequence to achieve a higher sampling rate with a TR of amp;lt; 1 s with acceptable spatial resolution. We further propose to incorporate temporal averaging of consecutively acquired EPI volumes to both ameliorate the reduced temporal signal-to-noise inherent in ultra-fast EPI sequences and reduce the data burden. BOLD data were collected from 11 healthy subjects performing a simple, event-related visual-motor task with four different EPI sequences: (1) reference EP/sequence with TR = 1440 ms, (2) shifted echo EP/sequence with TR = 700 ms, (3) shifted echo EPI sequence with every two consecutively acquired EPI volumes averaged and effective TR = 1400 ms, and (4) shifted echo EPI sequence with every four consecutively acquired EPI volumes averaged and effective TR = 2800 ms. Both the temporally averaged sequences exhibited increased temporal signal-to-noise over the shifted echo EPI sequence. The shifted echo sequence with every two EPI volumes averaged also had significantly increased BOLD signal change compared with the other three sequences, while the shifted echo sequence with every four EPI volumes averaged had significantly decreased BOLD signal change compared with the other three sequences. The results indicated that incorporating the method of shifted echo into a standard multi-slice EPI sequence is a viable method for achieving increased sampling rate for collecting event-related BOLD data. Further, consecutively averaging every two consecutively acquired EPI volumes significantly increased the measured BOLD signal change and the subsequently calculated activation map statistics.</p>