Table 3.
Recommended 1.5T protocol
| 3D T1w Pre | Ax 2D FLAIR | Ax 2D DWI | Ax 2D T2w | 3D T1w Postb | ||
|---|---|---|---|---|---|---|
| Sequence | IR-GREd,e | TSEc | EPIf | Contrast Injectiona | TSEc | IR-GREd,e |
| Plane | Sagittal/axial | Axial | Axial | Axial | Sagittal/axial | |
| Mode | 3D | 2D | 2D | 2D | 3D | |
| TR [ms] | 2100g | >6000 | >5000 | >3500 | 2100g | |
| TE [ms] | Min | 100–140 | Min | 100–120 | Min | |
| TI [ms] | 1100h | 2200 | 1100h | |||
| Flip angle | 10°–15° | 90°/≥160° | 90°/180° | 90°/≥160° | 10°–15° | |
| Frequency | ≥172 | ≥256 | 128 | ≥256 | ≥172 | |
| Phase | ≥172 | ≥256 | 128 | ≥256 | ≥172 | |
| NEX | ≥1 | ≥1 | ≥1 | ≥1 | ≥1 | |
| FOV | 256 mm | 240 mm | 240 mm | 240 mm | 256 mm | |
| Slice thickness | ≤1.5 mm | ≤4 mm | ≤4 mm | ≤4 mm | ≤1.5 mm | |
| Gap/spacing | 0 | 0 | 0 | 0 | 0 | |
| Diffusion optionsi |
b = 0, 500, and 1000 s/mm2
≥3 directions |
|||||
| Parallel imaging | No | Up to 2x | Up to 2x | Up to 2x | No | |
| Scan time (approximate) | 5–10 min | 4–5 min | 3–5 min | 3–5 min | 5–10 min |
Abbreviations: 3D, 3-dimensional; A/P, anterior to posterior; ADC, apparent diffusion coefficient; Ax, axial; DWI, diffusion-weighted imaging; EPI, echo-planar imaging; FLAIR, fluid-attenuated inversion recovery; FOV, field of view; IR-GRE, inversion-recovery gradient-recalled echo; MPRAGE, magnetization prepared rapid gradient-echo; NEX, number of excitations or averages; R/L, right to left; TSE, turbo spin-echo.
a0.1 mmol/kg or up to 20 cc (single, full dose) of MR contrast.
bPostcontrast 2D axial T1-weighted images should be collected with identical parameters to precontrast 2D axial T1-weighted images.
cTSE = turbo spin-echo (Siemens & Philips) is equivalent to FSE (fast spin-echo; GE, Hitachi, Toshiba).
dIR-GRE = inversion-recovery gradient-recalled echo sequence is equivalent to MPRAGE = magnetization prepared rapid gradient-echo (Siemens and Hitachi) and the inversion recovery spoiled gradient-echo (IR-SPGR or Fast SPGR with inversion activated or BRAVO; GE), 3D turbo field echo (TFE; Philips), or 3D fast field echo (3D Fast FE; Toshiba).
eA 3D acquisition without inversion preparation will result in different contrast compared with MPRAGE or another IR-prepped 3D T1-weighted sequences and therefore should be avoided.
fIn the event of significant patient motion, a radial acquisition scheme may be used (eg, BLADE [Siemens], PROPELLER [GE], MultiVane [Philips], RADAR [Hitachi], or JET [Toshiba]); however, this acquisition scheme can cause significant differences in ADC quantification and therefore should be used only if EPI is not an option.
gFor Siemens and Hitachi scanners. GE, Philips, and Toshiba scanners should use a TR = 5–15 milliseconds for similar contrast.
hFor Siemens and Hitachi scanners. GE, Philips, and Toshiba scanners should use a TI = 400–450 milliseconds for similar contrast.
iOlder model MR scanners that are not capable of >2 b-values should use b = 0 and 1000 s/mm2.