MRI scans were obtained with a 3-T clinical MR scanner (Philips Achieva) at CHLA. The default MRI protocol used by our institution for preoperative neuronavigation images was designated sequence 1 (S1) and consisted of an approximately 5-minute T1-weighted turbo field echo (TFE) sequence, including TR/TE 7/3.5 msec, flip angle (FA) 8°, matrix 252 × 217, in-plane resolution 1 × 1 mm, and slice thickness 1 mm. A summary of all evaluated sequence parameters is included (Table 1 ), and the acquisition times for standard diagnostic T1-weighted and T2-weighted scans are supplied in Supplemental Materials .
The aims of parameter refinement were to reduce the acquisition time and to maintain a high contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) on the skin surface. Moderate reductions in image resolution and SNR/CNR in the brain parenchyma itself were considered acceptable trade-offs. A single subject was scanned with all 13 image sequences to evaluate which were suitable for further evaluation in additional volunteers. We acquired baseline (S1) and improved (S5) images from 10 healthy volunteers (age range 25–38 years; 8 males and 2 females), as well as from a pediatric patient (12 years old) to demonstrate proof of concept.
The aims of parameter refinement were to reduce the acquisition time and to maintain a high contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) on the skin surface. Moderate reductions in image resolution and SNR/CNR in the brain parenchyma itself were considered acceptable trade-offs. A single subject was scanned with all 13 image sequences to evaluate which were suitable for further evaluation in additional volunteers. We acquired baseline (S1) and improved (S5) images from 10 healthy volunteers (age range 25–38 years; 8 males and 2 females), as well as from a pediatric patient (12 years old) to demonstrate proof of concept.