Diffusion-weighted single-shot echoplanar MR imaging for liver disease.

Area of Science:

• Radiology and Medical Imaging
• Oncology
• Biomedical Engineering

Background:

• Diffusion-weighted imaging (DWI) is a valuable MRI technique for assessing tissue microstructure.
• Apparent diffusion coefficients (ADCs) quantify water molecule diffusion, providing insights into tissue cellularity and integrity.
• Characterizing liver lesions is crucial for diagnosis and treatment planning, with DWI showing promise in differentiating lesion types.

Purpose of the Study:

• To determine apparent diffusion coefficients (ADCs) for abdominal organs and liver lesions.
• To investigate the influence of varying b values on ADC measurements.
• To evaluate the utility of ADCs in differentiating benign from malignant liver tumors.

Main Methods:

• Diffusion-weighted single-shot echo-planar imaging was performed on 6 healthy volunteers and 126 patients.
• Multiple b values were used, with a maximum of 846 sec/mm².
• ADCs were calculated for abdominal organs (liver, spleen, kidney) and liver lesions (49 malignant, 30 benign).

Main Results:

• ADCs decreased with increasing maximum b values across organs and lesions.
• Benign lesions exhibited significantly higher ADCs (2.49±1.39 x 10⁻³ mm²/sec) than malignant lesions (1.01±0.38 x 10⁻³ mm²/sec).
• Using a maximum b value of 846 sec/mm², an ADC threshold of 1.6 x 10⁻³ mm²/sec achieved 98% sensitivity and 80% specificity for malignancy.

Conclusions:

• ADC measurement shows significant potential for characterizing liver lesions.
• The magnitude of the maximum b value used in DWI influences calculated ADCs.
• Standardization of b values is recommended for reliable ADC-based differentiation of liver tumors.