PULMONARY NODULES

• Abnormal focal areas of radiodensity on CXR or CT are referred to as "nodules"
• Solitary pulmonary nodules are defined as intraparenchymal lung lesions < 3cm in diameter (Chest. 2003;123:89S-96S)
• CXR & CT cannot accurately distinguish benign from malignant nodules
• PET scans carry a sensitivity of between 80% and 90% and a specificity of approximately 85% for diagnosing cancer in solitary pulmonary nodules. Limitations include a reduced ability to detect bronchoalveolar and carcinoid tumors, and cancers <1 cm
• Lung Ca lesions frequently have high-affinity somatostatin receptors
• Scintigraphy with 99-technetium depreotide (synthetic somatostatin analogue) to distinguish benign from malignant nodules--
  • In a study of 114 pts with solitary nodules on CXR & CT (< 6cm in diameter) underwent SPECT with technetium depreotide and also tissue sampling; sensitivity for malignancy was 97%; specificity 73% (Chest 117:1232, 2000--JW)