PT  - JOURNAL ARTICLE
AU  - S.J. Holdsworth
AU  - K.W. Yeom
AU  - M.U. Antonucci
AU  - J.B. Andre
AU  - J. Rosenberg
AU  - M. Aksoy
AU  - M. Straka
AU  - N.J. Fischbein
AU  - R. Bammer
AU  - M.E. Moseley
AU  - G. Zaharchuk
AU  - S. Skare
TI  - Diffusion-Weighted Imaging with Dual-Echo Echo-Planar Imaging for Better Sensitivity to Acute Stroke
AID  - 10.3174/ajnr.A3921
DP  - 2014 Apr 24
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2014/04/17/ajnr.A3921.short
4100  - http://www.ajnr.org/content/early/2014/04/17/ajnr.A3921.full
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. Abbreviations DWdiffusion-weightedGRAPPAgeneralized autocalibrating partially parallel acquisitionGREgradiant-recalled echoPIparallel imagingR2relaxivity map