Strategies for improving the detection of fMRI activation in trigeminal pathways with cardiac gating.
Functional magnetic resonance imaging (fMRI) has become a powerful tool for studying the normal and diseased human brain. The application of fMRI in detecting neuronal signals in the trigeminal system, however, has been hindered by low detection sensitivity due to activation artifacts caused by cardiac pulse-induced brain and brainstem movement. A variety of cardiac gating techniques have been proposed to overcome this issue, typically by phase locking the sampling to a particular time point during each cardiac cycle. We sought to compare different cardiac gating strategies for trigeminal system fMRI. In the present study, we used tactile stimuli to elicit brainstem and thalamus activation and compared the fMRI results obtained without cardiac gating and with three different cardiac gating strategies: single-echo with TR of 3 or 9 heartbeats (HBs) and dual-echo T2*-mapping EPI (TR = 2 HBs, TE = 21/55 ms). The dual-echo T2* mapping and the single-echo with TR of 2 and 3 HBs cardiac-gated fMRI techniques both increased detection rate of fMRI activation in brainstem. Activation in the brainstem and the thalamus was best detected by cardiac-gated dual-echo EPI.
Zhang
Wei-Ting
WT
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, and Harvard Medical School, Bldg 149 (2301), 13th Street, Charlestown, MA 02129, USA. wtzhang@nmr.mgh.harvard.edu
Mainero
Caterina
C
Kumar
Ashok
A
Wiggins
Christopher J
CJ
Benner
Thomas
T
Purdon
Patrick L
PL
Bolar
Divya S
DS
Kwong
Kenneth K
KK
Sorensen
A Gregory
AG
D000328:Adult; D000465:Algorithms; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008959:Models, Neurological; D010812:Physical Stimulation; D011149:Pons / Q000033:anatomy & histology / Q000502:physiology; D013788:Thalamus / Q000033:anatomy & histology / Q000502:physiology; D014110:Touch / Q000502:physiology; D014278:Trigeminal Nuclei / Q000033:anatomy & histology* / Q000502:physiology*