Can malignant and benign pulmonary nodules be differentiated with diffusion-weighted MRI?

Area of Science:

• Radiology
• Medical Imaging
• Oncology

Background:

• Pulmonary nodules require accurate differentiation between malignant and benign types for appropriate patient management.
• Diffusion-weighted imaging (DWI) is an emerging technique in thoracic imaging.

Purpose of the Study:

• To assess the utility of diffusion-weighted imaging (DWI) with a high b factor in distinguishing malignant from benign pulmonary nodules.

Main Methods:

• 54 pulmonary nodules (>= 5 mm) in 51 patients were analyzed using DWI (b factor = 1,000 s/mm²).
• Two radiologists independently scored nodule signal intensity on a 5-point scale.
• Statistical analysis included the Mann-Whitney U test and ROC curve analysis.

Main Results:

• Malignant nodules exhibited significantly higher signal intensity scores (mean 4.03) compared to benign nodules (mean 2.50) (p < 0.01).
• The area under the ROC curve was 0.796, indicating good diagnostic performance.
• With a threshold score of 3, sensitivity was 88.9%, specificity 61.1%, and accuracy 79.6%.

Conclusions:

• Signal intensity on DWI is a potentially useful parameter for differentiating malignant and benign pulmonary nodules.
• Careful interpretation is necessary for small metastatic nodules, nonsolid adenocarcinomas, granulomas, and inflammatory nodules.