Chemical shift-encoded multishot EPI for navigator-free prostate DWI

Area of Science:

• Radiology
• Medical Imaging
• Biophysics

Background:

• Diffusion-weighted imaging (DWI) is crucial for prostate cancer detection.
• Standard single-shot EPI (ssh-EPI) suffers from geometric distortions and fat signal interference.
• Multishot EPI (mse-EPI) faces challenges with motion-induced phase variations.

Purpose of the Study:

• Introduce a navigator-free Dixon 3-shot-EPI protocol for prostate DWI.
• Overcome limitations of ssh-EPI, including geometric distortions and fat signal interference.
• Address phase variations in mse-EPI while enabling water/fat separation.

Main Methods:

• Acquired DWI data from 7 healthy volunteers using Dixon 3-shot EPI and standard fat-suppressed ssh-EPI.
• Compared image quality via Likert scale ratings by two readers.
• Quantitatively compared apparent diffusion coefficient (ADC) values.
• Applied the protocol to two patients to assess clinical feasibility.

Main Results:

• Dixon 3-shot EPI significantly reduced geometric distortion (p < 0.01) compared to ssh-EPI.
• No significant differences in edge definition, SNR, or overall image quality were observed.
• Dixon mse-EPI offered advantages like B0 map-driven distortion correction and superior fat suppression.
• Lesions were clearly identifiable in both protocols on ADC maps in patient data.

Conclusions:

• The proposed Dixon 3-shot-EPI protocol is a promising alternative to ssh-EPI for prostate DWI.
• It offers reduced geometric distortions and improved fat suppression.
• The protocol addresses common DWI issues and enhances scanning flexibility for optimized imaging.