Diffusion-weighted imaging with dual-echo echo-planar imaging for better sensitivity to acute stroke

Area of Science:

• Magnetic Resonance Imaging
• Neuroradiology
• Medical Imaging Techniques

Background:

• Parallel imaging accelerates echo-planar imaging (EPI) acquisition by reducing echo time (TE).
• This acceleration allows for dual-echo acquisitions, capturing images at both short and long TEs within a single diffusion-preparation period.

Purpose of the Study:

• To investigate the utility of a parallel imaging-enhanced dual-echo EPI sequence.
• To improve lesion conspicuity in diffusion-weighted imaging (DWI) for stroke evaluation.

Main Methods:

• Acquired parallel imaging-enhanced dual-echo DWI data in 50 patients suspected of stroke at 1.5T.
• Utilized dual-echo EPI with TE1 = 48 ms and TE2 = 105 ms.
• Neuroradiologists graded lesion conspicuity, diagnostic confidence, and image quality, comparing with routine DWI.

Main Results:

• Both echo 1 and echo 2 DWIs were rated superior to the reference DWI.
• Echo 2 demonstrated superior sensitivity for detecting acute infarcts, unanimously favored over echo 1 and reference DWI.
• Echo 1 offered better overall image quality and higher SNR ADC maps for infarct specificity.

Conclusions:

• Parallel imaging-enhanced dual-echo DWI is effective for evaluating lesions with restricted diffusion.
• The longer TE of echo 2 significantly enhances lesion conspicuity.
• Echo 1 provides valuable ADC maps for specificity, and relaxivity maps may offer complementary information.