New Imaging Strategies Using a Motion-Resistant Liver Sequence in Uncooperative Patients

Table 1

Parameters for the motion-resistant protocol used for 3.0T MR imaging scanners.

Parameter	Precontrast sequences			Postcontrast sequences
	T1-weighted 2D MP-RAGE in-phase/out-of-phase	T2-weighted SS-ETSE	BLADE	T1-weighted 3D-GRE with CAIPIRINHA	T1-weighted 3D-GRE with CAIPIRINHA (echo-sharing technique)	T1-weighted radial 3D-GRE	T1-weighted radial 3D-GRE (KWIC technique)
Plane of acquisition	Axial	Axial, coronal	Axial	Axial, coronal	Axial	Axial	Axial
TR (milliseconds)	1500	1200	3910	4.6	4.7	3.4	3.1
TE (milliseconds)	2.3/3.4	150	105	2.2	1.5	1.7	1.5
TI (milliseconds)	1200
Flip angle (°)	20	120	160	12	12	12	12.5
Echo train length		102	23	1	2
Parallel imaging	GRAPPA 2	GRAPPA 2	GRAPPA 2	2D CAIPIRINHA; 2 × 2	2D CAIPIRINHA 2 × 2	GRAPPA 2	GRAPPA 2
BW/pixel (Hz)	210/180	710	300	395	870	870	1040
Matrix (frequency × phase)	256 × 173	320 × 213	320 × 320	384 × 227	384 × 211	384 × 384	320 × 320
FOV (mm)	302 × 304	302 × 394	380 × 380	302 × 227	296 × 299	340 × 340	340 × 340
Number of sections	36	36	36	80	80	80	80
Section thickness (mm)	5	5	5	2.5	2.5	2.5	3.0
Intersectional gap (mm)	1.5	1.5	1.5	0	0	0	0
Number of signal acquisitions	1	1		1	1	1	1
Fat suppression	None	Fat sat for axial, none for coronal	Fat sat	Fat sat	Fat sat	Fat sat	Fat sat
Respiratory control	BI	BI	FB	BH	BH	FB	BH

BH, breath-hold; BI, breathing-independent; BLADE, proprietary name for periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) in MR systems from Siemens Medical Solutions; BW, bandwidth; Hz, Hertz; CAIPIRINHA, controlled aliasing in parallel imaging results in higher acceleration; FB, free breathing; FOV, field of view; GRE, gradient recalled echo; KWIC, k-space weighted image contrast; MP-RAGE, magnetization-prepared rapid-acquisition gradient echo; sat, saturation; SS-ETSE, single-shot echo-train spin-echo; TE, echo time; TI, inversion time; TR, repetition time.