Characterization of adrenal masses with diffusion-weighted imaging

Area of Science:

• Radiology
• Medical Imaging
• Oncology

Background:

• Adrenal masses require accurate characterization to distinguish between benign and malignant lesions.
• Diffusion-weighted MRI (DWI) is a technique used to assess tissue microstructure.
• Apparent diffusion coefficient (ADC) values derived from DWI can provide quantitative information about tissue water diffusion.

Purpose of the Study:

• To evaluate the effectiveness of diffusion-weighted MRI (DWI) in characterizing adrenal masses.
• To determine the role of apparent diffusion coefficient (ADC) measurements in differentiating benign from malignant adrenal lesions.

Main Methods:

• Retrospective review of 49 adrenal lesions in 48 patients using MRI.
• Analysis of signal intensities on T1-weighted imaging (in-phase and opposed-phase) and ADC values.
• Quantitative assessment using signal intensity index, adrenal-to-spleen ratio, and ADC values, both independently and combined.
• Logistic regression and receiver operating characteristic (ROC) curve analysis were performed.

Main Results:

• Apparent diffusion coefficient (ADC) values were not found to be significant predictors of lesion status on multivariate analysis.
• No significant difference in diagnostic performance was observed for ADC, signal intensity index, adrenal-to-spleen ratio, or their combination on ROC analysis.
• For indeterminate lesions based on signal intensity index, ADC values showed potential utility: values > 1.50 × 10(-3) mm(2)/s were exclusively in benign lesions, and values < 1.0 × 10(-3) mm(2)/s were predominantly in malignant lesions.

Conclusions:

• Apparent diffusion coefficient (ADC) values alone are generally not effective for differentiating adrenal lesions.
• ADC measurements may assist in characterizing a subset of adrenal lesions that are indeterminate based on signal intensity index, potentially improving diagnostic accuracy.