Achieva 1.5t mri scanner

Subjects were placed in a MRI compatible papoose (Universal Medical, Norwood, MA) to minimize movement artifact following published recommendations [20 (link)] and scanned on a Philips Achieva 1.5 T MRI scanner (Philips, Amsterdam, Netherlands). Infants were swaddled and fed prior to MRI when possible. Those who fell asleep were scanned without sedation. Those who were fussy received oral chloral hydrate. None of the infants were intubated or given narcotics for the purposes of the study scan. T2-weighted images (dual echo, turbo spin echo, TR = 3 s, TE = 16.8 and 210 ms, in-plane resolution 0.7 × 0.7 mm, number of slices = 18, slice thickness = 4 mm, slice gap = 1 mm, number of acquisitions = 3, echo train length = 16, scan time = 6:06) and T1-weighted images (inversion-prepped turbo spin echo, TR = 8.3 s, TE = 15 ms, in-plane resolution. 0.7 × 0.7 mm, number of slices = 18, slice thickness = 4 mm, slice gap = 1 mm, number of acquisitions = 2, echo train length = 16, scan time = 3:03, inversion delays T1 = 300, 500, 700, 1000, 1500, 2000, and 2500 ms) were acquired. Images were oriented in coronal planes for all subjects.

The MRI scans were acquired on an Achieva 1.5 T MRI scanner (Software release 2.6.1, Philips Healthcare) using an eight channel SENSE head coil. The scans included (i) 3D B₀ mapping (3D sagittal T1-FFE, TR = 10 ms, acquisition voxel 2 × 2 × 2 mm³, acquisition array size 70(RL) × 112(AP) × 112(HF), 2 acquisitions with different TEs at 3.00 ms and 3.07 or 3.20 ms), (ii) Multi-slice spin-echo (SE) imaging as a geometrical reference (FOV = 250 mm, TR/TE = 479/12 ms, slice thickness = 4.0 mm, gap = 0.4 mm, number of slices = 35, water-fat shift = 1.5 mm in AP direction), and (iii) diffusion weighted imaging (DWI) using EPI readout (FOV = 250 mm, TR/TE = 4682/74 ms, slice thickness = 4.0 mm, gap = 0.4 mm, number of slices = 35, water-fat shift of 33 mm in the AP direction, b = 0, 1000 mm²/s). Diffusion-weighted imaging is particularly important for examination of stroke^{16 (link),17 (link)}.

Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were performed using the Philips Achieva 1.5T MRI scanner in accordance with standard operating procedures. All neuroimaging data were evaluated by two independent, accredited, and experienced neuroimaging experts. Depending on the presence of lacunar infarction, two separate groups were set: the lacunar infarction group and the no lacunar infarction group. The degree of white matter damage was classified into four levels according to the age-related white matter change (ARWMC) rating scale, namely, grade 0 = no lesions, grade 1 = focal damage, grade 2 = partial fusion of lesions, and grade 3 = diffuse involving the entire area, with or without “U”-fiber involvement. Depending on the lesion range, two separate groups were set: the absent-to-mild white matter damage group (0–1 grade) and the moderate-to-severe white matter damage group (grade 2–3). Typical images are shown in Figure 1.

T1-weighted (T1W) brain images in the sagittal plane were obtained with a Philips Achieva 1.5-T MRI scanner with an eight-channel SENSE head coil using a 3D turbo field echo (TFE) sequence with the following parameters: 160 contiguous slices; TR/TE, 9.9/3.7 ms; matrix size, 256 × 256; voxel size, 1 × 1 × 1 mm. Head movement was minimized by the use of foam pads placed within the head coil.