RT Journal Article
SR Electronic
T1 Diffusion-Weighted Imaging with Dual-Echo Echo-Planar Imaging for Better Sensitivity to Acute Stroke
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 1293
OP 1302
DO 10.3174/ajnr.A3921
VO 35
IS 7
A1 Holdsworth, S.J.
A1 Yeom, K.W.
A1 Antonucci, M.U.
A1 Andre, J.B.
A1 Rosenberg, J.
A1 Aksoy, M.
A1 Straka, M.
A1 Fischbein, N.J.
A1 Bammer, R.
A1 Moseley, M.E.
A1 Zaharchuk, G.
A1 Skare, S.
YR 2014
UL http://www.ajnr.org/content/35/7/1293.abstract
AB BACKGROUND AND PURPOSE: Parallel imaging facilitates the acquisition of echo-planar images with a reduced TE, enabling the incorporation of an additional image at a later TE. Here we investigated the use of a parallel imaging–enhanced dual-echo EPI sequence to improve lesion conspicuity in diffusion-weighted imaging. MATERIALS AND METHODS: Parallel imaging–enhanced dual-echo DWI data were acquired in 50 consecutive patients suspected of stroke at 1.5T. The dual-echo acquisition included 2 EPI for 1 diffusion-preparation period (echo 1 [TE = 48 ms] and echo 2 [TE = 105 ms]). Three neuroradiologists independently reviewed the 2 echoes by using the routine DWI of our institution as a reference. Images were graded on lesion conspicuity, diagnostic confidence, and image quality. The apparent diffusion coefficient map from echo 1 was used to validate the presence of acute infarction. Relaxivity maps calculated from the 2 echoes were evaluated for potential complementary information. RESULTS: Echo 1 and 2 DWIs were rated as better than the reference DWI. While echo 1 had better image quality overall, echo 2 was unanimously favored over both echo 1 and the reference DWI for its high sensitivity in detecting acute infarcts. CONCLUSIONS: Parallel imaging–enhanced dual-echo diffusion-weighted EPI is a useful method for evaluating lesions with reduced diffusivity. The long TE of echo 2 produced DWIs that exhibited superior lesion conspicuity compared with images acquired at a shorter TE. Echo 1 provided higher SNR ADC maps for specificity to acute infarction. The relaxivity maps may serve to complement information regarding blood products and mineralization. DWdiffusion-weightedGRAPPAgeneralized autocalibrating partially parallel acquisitionGREgradiant-recalled echoPIparallel imagingR2relaxivity map