Reduced-distortion diffusion MRI of the craniovertebral junction

Area of Science:

• Radiology
• Neuroimaging
• Diffusion Tensor Imaging

Background:

• Diffusion imaging of the craniocervical junction (CVJ) is often hindered by susceptibility and distortion artifacts.
• These artifacts can complicate the interpretation of diffusion-weighted images in the CVJ region.

Purpose of the Study:

• To compare the efficacy of Read-out Segmented Echo-Planar Imaging (RS-EPI) with Segmented Echo-Planar Imaging (SS-EPI) for diffusion MR imaging of the CVJ.
• To evaluate the potential of RS-EPI in reducing artifacts and improving image quality for CVJ assessment.

Main Methods:

• Acquisition of diffusion tensor imaging (DTI) data from 10 healthy volunteers using both RS-EPI and SS-EPI sequences on a 3T MRI scanner.
• Standardized imaging parameters including 1-mm in-plane resolution, 3-mm slice thickness, and b-values of 0 and 1000 s/mm².
• Quantitative and qualitative assessment of image distortion, delineation of anatomical structures, and visualization of fine details by two independent readers.

Main Results:

• RS-EPI demonstrated significantly reduced geometric distortion compared to SS-EPI (P < .01).
• Improved delineation of the temporal lobe and cerebellar contours was observed with RS-EPI.
• Enhanced visualization of fine structures within the brainstem and cerebellum was achieved using the RS-EPI sequence.

Conclusions:

• RS-EPI is less susceptible to geometric distortion than SS-EPI, leading to superior delineation of the CVJ's internal structure.
• Despite a comparable acquisition time, RS-EPI shows promise for DTI studies in CVJ lesions.
• Potential applications include the diagnosis of brainstem ischemia, neurodegenerative diseases, tumors, and inflammatory conditions affecting the CVJ.