Comparison of Point Spread Function Encoding EPI DWI and Turbo Gradient Spin Echo BLADE DWI for Imaging Intracranial...

To compare the image quality and quantitative parameters of point spread function-encoded echo planar imaging (PSF-EPI) and turbo gradient spin echo BLADE (TGSE-BLADE) for distortion-free diffusion-weighted imaging (DWI) of intracranial tumors.

This prospective study included 37 patients (18 males, 19 females, median age: 11 years) with intracranial tumors who underwent 3 T MRI using both PSF-EPI and TGSE-BLADE DWI sequences. Two radiologists independently evaluated qualitative parameters, including tumor depiction, artifacts, geometric distortion, and overall image quality on a 5-point scale. Quantitative metrics, including signal-to-noise ratio (SNR), contrast, contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC), were measured. Statistical methods included paired tests, Cohen's Kappa statistics, and Bland-Altman analysis for assessing ADC agreement in normal-appearing white matter and tumors.

PSF-EPI demonstrated significantly better tumor depiction (p<0.01) and overall image quality (p<0.01) than TGSE-BLADE, with no significant difference in artifact (p=0.256) or distortion scores (p=0.389). Inter-rater agreement was substantial to almost perfect. Quantitatively, PSF-EPI yielded significantly higher SNR (p<0.001), whereas CNR was comparable between the two sequences (p=0.988). Tumor contrast was slightly higher in TGSE-BLADE than in PSF-EPI (p=0.034). In normal-appearing white matter, ADC measurements showed good agreement with only a small mean difference and no significant inter-sequence difference (p=0.097). Likewise, no significant inter-sequence difference in lesion ADC was observed (p=0.195), although ADC differences in tumors showed wider dispersion than those in normal-appearing white matter on Bland-Altman analysis.

While both sequences provide distortion-free imaging, PSF-EPI offers superior image quality and significantly higher measured SNR. ADC measurements were comparable between PSF-EPI and TGSE-BLADE. These findings support the use of PSF-EPI as a robust technique for intracranial tumor imaging, particularly when lesion conspicuity and anatomical delineation are clinically prioritized.