Diagonal DWI: A Time-Efficient Alternative to 3-Scan Trace DWI for Breast Lesion Evaluation at 3.0-T MRI-A Phantom...

Diffusion-weighted imaging (DWI) in breast MRI requires balancing image quality with acquisition time. Reducing scan time without sacrificing diagnostic performance could improve patient comfort and workflow.

To compare 3-scan trace DWI (tDWI) and diagonal DWI (dDWI) for breast lesion evaluation using both phantom and clinical assessments, focusing on image quality metrics and diagnostic performance.

Retrospective comparative study.

A commercially available breast diffusion phantom (Caliber MRI; Boulder, CO, USA) and 92 consecutive participants were initially enrolled. After excluding 23 due to having no confirmed lesion, and 15 with non-mass lesions, 54 patients (median age 55.5 years, range 21-82) were analyzed.

3-T, tDWI (120 s) and dDWI (74 s) with identical parameters except for diffusion gradient directions, with dDWI reducing scan time by 38%.

Phantom studies measured apparent diffusion coefficient (ADC) and estimated signal-to-noise ratio (eSNR). Clinical studies evaluated ADC, contrast-to-noise ratio (CNR), and contrast ratio (CR) from ROIs in lesions, normal breast tissue, and fat. Three radiologists scored lesion conspicuity and image quality.

Due to non-normal data distribution, the Wilcoxon signed-rank test compared metrics between sequences. The ADC coefficient of variation (CV) was calculated. A p-value < 0.05 was considered significant.

dDWI significantly improved image quality by reducing artifacts, especially those originating from the nipple and in the breast tissue periphery, and slightly better lesion conspicuity. No significant difference was found for eSNR in breast phantom studies (p = 0.31 for b = 0; and p = 0.84 for b = 800 s/mm²). tDWI demonstrated significantly higher CNR for breast tissue and fat. tDWI also showed lower CR values for tumor/breast tissue and lower values for tumor/fat. ADC measurements were similar between techniques (CV = 4.20%).

dDWI provides a 38% shorter acquisition time than tDWI while maintaining comparable quantitative performance. dDWI demonstrates improved image quality, particularly in challenging anatomical regions, though tDWI yields higher contrast-to-noise ratio values.

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