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 S.J. Holdsworth
A1 K.W. Yeom
A1 M.U. Antonucci
A1 J.B. Andre
A1 J. Rosenberg
A1 M. Aksoy
A1 M. Straka
A1 N.J. Fischbein
A1 R. Bammer
A1 M.E. Moseley
A1 G. Zaharchuk
A1 S. Skare
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