MRI Evaluation of Indeterminate Pulmonary Nodules

Area of Science:

• Radiology
• Pulmonary Medicine
• Oncology

Background:

• Pulmonary nodules require accurate differentiation from benign and malignant pathologies.
• Distinguishing pulmonary hamartomas from other lung nodules, such as carcinoid tumors and non-small cell lung cancer (NSCLC), is crucial for appropriate patient management.

Purpose of the Study:

• To evaluate specific Magnetic Resonance Imaging (MRI) features for differentiating pulmonary hamartomas from other nodule pathologies.
• To assess the diagnostic utility of enhancement patterns and signal intensity index (SII) in identifying hamartomas.

Main Methods:

• A retrospective analysis of chest MRIs from 48 patients with pathologically confirmed or stable follow-up diagnosed pulmonary nodules.
• Two blinded radiologists assessed enhancement patterns (solid, rim, speckled/mesh) and calculated SII using chemical shift imaging.

Main Results:

• Hamartomas, carcinoid tumors, and adenocarcinomas were the most common diagnoses.
• Rim and speckled/mesh enhancement patterns were significantly more prevalent in hamartomas (P<0.001).
• A signal intensity index (SII) >10% demonstrated 100% specificity for hamartomas, and combining enhancement patterns with SII >10% achieved 96.6% specificity.

Conclusions:

• Chemical shift imaging, while diagnostic for hamartomas, shows signal dropout in over half of cases.
• Specific MRI enhancement patterns (rim or speckled/mesh) are highly suggestive of hamartomas.
• Combining MRI features like enhancement patterns and SII improves diagnostic accuracy for pulmonary hamartomas, potentially reducing unnecessary follow-up or invasive procedures.