Diffusion-weighted MR imaging of thyroid nodules

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Thyroid nodules are common, and differentiating benign from malignant types is crucial for patient management.
• Fine needle aspiration biopsy (FNAB) cytology is the standard reference, but can have limitations.

Purpose of the Study:

• To evaluate the diagnostic utility of diffusion-weighted imaging (DWI) in differentiating malignant and benign thyroid nodules.
• To compare apparent diffusion coefficient (ADC) values between malignant and benign nodules, and normal thyroid parenchyma.

Main Methods:

• Seventy-six patients with thyroid nodules and 20 healthy subjects underwent diffusion-weighted MR imaging.
• Three b-factors (100, 200, 300 mm²/s) were used to calculate ADC values for nodules and normal thyroid tissue.
• Statistical analysis compared ADC values between nodule types and control groups.

Main Results:

• Mean ADC values were significantly lower for malignant nodules compared to benign nodules across all b-factors.
• ADC values for normal thyroid parenchyma were similar in patients with nodules and healthy subjects.
• ADC values for malignant nodules: 0.96±0.65 (b=100), 0.56±0.43 (b=200), 0.30±0.20 (b=300) x 10⁻³ mm²/s.
• ADC values for benign nodules: 3.06±0.71 (b=100), 1.80±0.60 (b=200), 1.15±0.43 (b=300) x 10⁻³ mm²/s.

Conclusions:

• Diffusion-weighted imaging (DWI) shows potential as a non-invasive tool for differentiating malignant and benign thyroid nodules.
• Lower ADC values are indicative of malignancy in thyroid nodules.