• S J Holdsworth, K W Yeom, M U Antonucci, J B Andre, J Rosenberg, M Aksoy, M Straka, N J Fischbein, R Bammer, M E Moseley, G Zaharchuk, and S Skare.
• From the Department of Radiology (S.J.H., K.W.Y., M.U.A., J.R., M.A., M.S., N.J.F., R.B., M.E.M., G.Z.), Stanford University, Stanford, California sholdsworth@stanford.edu.
• AJNR Am J Neuroradiol. 2014 Jul 1; 35 (7): 1293-302.

Background And PurposeParallel 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 MethodsParallel 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.ResultsEcho 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.ConclusionsParallel 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.© 2014 by American Journal of Neuroradiology.

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