High resolution echo planar imaging (HR-EPI) images were also acquired with geometric distortions to match those of the DTI data (Boulby et al., 2005).
In addition to the fMRI data, for each subject we acquired a high resolution echo planar image covering the whole brain with the following parameters: two shots, echo time = 30 ms, repetition time = 4500 ms, matrix 256 × 256, 88 contiguous 1.5 mm slices.
In addition to the functional MRI data, we acquired a high resolution echo planar image covering the whole brain with the following parameters for each subject: two shots, echo time 30 ms, repetition time 4500 ms, matrix 256 × 256, 88 contiguous 1.5 mm slices; the geometric distortions were matched by introducing an additional delay to increase the echo spacing (Boulby et al., 2005).
After preprocessing, the functional images were registered to the corresponding high-resolution echo planar images, (co-registered to T1-weighted images,) which were registered to the 2 mm isotropic MNI-152 standard space image [18].
For each subject, we acquired a high-resolution echo planar image (EPI) covering the whole brain.
Functional data were collected using high-resolution echo planar T2∗-weighted imaging (40 oblique axial slices, repetition time [TR] 2490 ms, echo time [TE] 30 ms, in-plane resolution 2 × 2 mm, slice thickness 2 mm plus a 25% slice gap, 192 × 192 mm field of view).
Functional data were collected using high-resolution echo planar T2*-weighted imaging (EPI, 40 oblique axial slices, time repetition [TR] 2490 ms, time echo [TE] 30 ms, in-plane resolution 2 × 2 mm, slice thickness 2 mm plus a 25% slice gap, 192 × 192 mm field of view).
More recently, gradient echo imaging on MR and susceptibility weighted imaging (SWI), a high resolution gradient echo sequence, are even more sensitive in detecting subtle blood products in the brain.
Sequences included high resolution turbospin echo (TSE) T2-weighted imaging [repetition time (TR)/echo time (TE): 6,000 10,000 ms/136 ms, echo train length (ETL): 61, number of acquisitions: 3] in the axial, coronal, and sagittal planes, and fat-suppressed spin echo T1-weighted imaging (740 790/19, number of acquisitions: 2) in the axial and sagittal plane, using a multislice technique.
21 healthy participants (16 female) were scanned on a 3T scanner with a standardized trigeminal nociceptive stimulation protocol for event-related fMRI using a specifically designed sequence for high resolution brainstem echo planar imaging as well as a brainstem specific noise correction technique and brainstem template.
In all specimens T1-weighted, T2-weighted and High Resolution Gradient Echo sequences were employed.
