Small solid renal masses: characterization by diffusion-weighted MRI at 3 T.

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Small solid renal lesions require accurate characterization.
• Differentiating benign from malignant renal masses is crucial for patient management.

Purpose of the Study:

• To describe the appearance of small solid renal lesions (≤3 cm) on diffusion-weighted MRI.
• To evaluate the utility of apparent diffusion coefficient (ADC) measurements in distinguishing benign from malignant renal masses.

Main Methods:

• Retrospective analysis of 47 small renal masses in 35 patients using 3 Tesla MRI with diffusion-weighted sequences.
• Qualitative and quantitative analysis of diffusion-weighted images and ADC maps.

Main Results:

• Small renal lesions appeared hyperintense on high b-value images and hypointense on ADC maps.
• Mean ADC values were significantly lower in renal masses compared to normal kidney parenchyma (1.22 ± 0.3 vs 1.85 ± 0.12 mm²/s).
• Distinct ADC values were observed for different renal tumor subtypes, including renal cell carcinomas, metastases, angiomyolipomas, and oncocytomas.

Conclusions:

• Diffusion-weighted MRI is valuable for characterizing small solid renal masses.
• ADC measurements show potential in differentiating benign from malignant renal lesions and classifying tumor subtypes.