Utilizing generalized autocalibrating partial parallel acquisition (GRAPPA) to achieve high-resolution contrast-enhanced MR angiography of hepatic artery: initial experience in orthotopic liver transplantation candidates

Purpose:To compare and evaluate images acquired with two different MR angiography (MRA) sequences, three-dimensional (3D) half-Fourier fast spin-echo (FSE) and 3D true steady-state free-precession (SSFP) combined with two time-spatial labeling inversion pulses (T-SLIPs), for selective and non-contrast-enhanced (non-CE) visualization of the portal vein. Materials and Methods:Twenty healthy volunteers were examined using half-Fourier FSE and true SSFP sequences on a 1.5T MRI system with two T-SLIPs, one placed on the liver and thorax, and the other on the lower abdomen. For quantitative analysis, vessel-to-liver contrast (Cv-l) ratios of the main portal vein (MPV), right portal vein (RPV), and left portal vein (LPV) were measured. The quality of visualization was also evaluated. Results:In both pulse sequences, selective visualization of the portal vein was successfully conducted in all 20 volunteers. Quantitative evaluation showed significantly better Cv-l at the RPVs and LPVs in half-Fourier FSE (P Ͻ 0.0001). At the MPV, Cv-l was better in true SSFP, but was not statistically different. Visualization scores were significantly better only at branches of segments four and eight for half-Fourier FSE (P ϭ 0.001 and 0.03, respectively). Conclusion:Both 3D half-Fourier FSE and true SSFP scans with T-SLIPs enabled selective non-CE visualization of the portal vein. Half-Fourier FSE was considered appropriate for intrahepatic portal vein visualization, and true SSFP may be preferable when visualization of the MPV is required.

Section: Quantitative Evaluationmentioning

confidence: 99%

Section: Quantitative Evaluationmentioning

confidence: 99%

Non‐contrast‐enhanced MR portography with time‐spatial labeling inversion pulses: Comparison of imaging with three‐dimensional half‐fourier fast spin‐echo and true steady‐state free‐precession sequences

Shimada

Isoda

Okada

et al. 2009

“…where DT is the delay time, TT is the measured contrast material transit time, IT is the total contrast material injection time, and AC is the acquisition time (14,15). The portal venous and equilibrium phases were obtained at 15 and 100 seconds after the end of the arterial phase scan, respectively.…”

Section: Mri Techniquementioning

confidence: 99%

Comparison of dynamic MRI at 3.0T and MDCT of pancreatobiliary disease: Evaluation with source, MPR, CPR, and MIP images for image quality and hepatic arterial and portal venous vessel conspicuity

Uchida

Sakoda

Arikawa

et al. 2009

“…Relative signal intensity (SI) of the target organ compared with that of reference tissue was adopted for quantitative evaluation (11), because the conventionally used method to determine the signal-to-noise ratio (SNR), which is derived from two separate regions of interest (ROIs) in a single image, was difficult to apply due to the use of the parallel imaging (12). The SI of the ECA was compared with that of the muscle adjacent to it for all sequences.…”

Section: Quantitative Evaluationmentioning

confidence: 99%

Visualization of external carotid artery and its branches: Non–contrast‐enhanced MR angiography using balanced steady‐state free‐precession sequence and a time‐spatial labeling inversion pulse

Satogami

Okada

Koyama

et al. 2009

Purpose: To evaluate visibility of the external carotid artery (ECA) and its branches using three-dimensional (3D) balanced steady-state free-precession (SSFP) MR angiography with a time-spatial labeling inversion pulse (Time-SLIP), and to provide an optimal value of the inversion time (TI). Materials and Methods:Peripheral-pulse-wave-gated 3D balanced SSFP images were obtained in 20 healthy volunteers. Images with a Time-SLIP using four different TIs (600, 900, 1200, and 1500 ms) and without a Time-SLIP, referred to as sequence A to E, were acquired for each subject and compared for visibility scores of ECA system and relative signal intensity (SI) of ECA.Results: Average Friedman rank for overall visibility was 1.63, 3.01, 3.59, 3.58, and 3.20 for sequence A to E, respectively. Sequence C and D yielded significantly higher visibility than sequence A, B, and E. The mean relative SI value was 0.97, 0.87, 0.81, 0.76, and 0.67 for sequence A to E, respectively. Conclusion:Balanced SSFP MR angiography with a Time-SLIP is superior to that without a Time-SLIP, showing excellent visualization of ECA system in approximately 3 min in average with sufficient background suppression including veins and salivary ducts. A TI of 1200 ms was considered to be optimal for this purpose.