1. Lung Nodules Frans Naudé

2. Definition of Pulmonary nodule • Rounded opacity , moderately well defined • < 3cm in diameter Web p 97

3. General Approach to lung nodules Position • Is it a lung nodule? • Skin tags, nipple shadows, bone lesions • Distribution in the lung Number of Nodules ( SPN, Multiple) Compare with previous radiographs Interpreting CXR p102

4. Web p185

5. P84, Computed Tomography of the Lung, Verschakelen

6. Lung nodules: Imaging Modalities • CXR • CT ( HRES) • PET/CT : F18-FDG

7. Description of pulmonary nodule • Pattern of distribution (Relationship to fissures, pleura, secondary lobules) • Edge characteristics (sharp, poorly circumscribed, ground glass) • Morphology ( branching/ tree in bud) • Size: • Pulmonary nodule <3cm • Small nodule < 1cm Web p97 High resolution CT of the lung

8. Large nodules 1-3cm(Easily seen on CXR)

9. HRES CTAnatomy of pulmonary lobule

10. Secondary pulmonary lobule interlobular septa centrilobular region lobular lung parenchyma Blue = Pulmonary veins Green = lymphatic's Yellow= bronchiolar branches Red = Arteries White = Connective tissue Computed Tomography of the lung p9

11. Secondary pulmonary lobule Prof Naidich

12. HRES CT • Interstitial nodules vs Air space nodules

13. WEB-Algorithmic approach to nodules P120 High resolution CT lung ,Web - approach

14. CT of the lung , p74

15. CT of the lung , p72

16. HRES CT High resolution CT lung ,Web – Algorithm 4

17. Airspace nodules • = centrilobular distribution • = no pleural/septal nodules • Ground-glass opacification/ less dense than adjacent blood vessels

18. Centrilobular nodules : Tree in Bud

19. Tree – in - Bud • PT with TB • Indicative of endobronchial spread P83, Computed Tomography of the Lung,Verschakelen

20. Infective bronchiolitis • Tree in Bud appearance • Bronchial wall thickening Computed Tomography of the Lung,Verschakelen

21. HRES CTTree in bud absent High resolution CT lung ,Web - approach

22. Centrilobular: Tree in bud absent

23. Poorly defined hazy ground glass nodules • Respiratory bronchiolitis • Langercellhistiocytosis • Lymphocytic interstitial pneumonitis

25. Interstitial nodules • = pleural/ septal predominance

26. HRES CTPerilymphatic High resolution CT lung ,Web - approach

28. Perilymphatic disease • Clustered nodules • Adjacent to fissures and pleural surfaces and along central vascular structures • DDX: Sarcoid, silicosis, CWP. • Rare: Amyloid ,LIP

29. Sarcoidosis P83, Computed Tomography of the Lung,Verschakelen

30. Silicosis Web p305

31. Web p 306

32. Coal workers pneumoconiosis Web p 306 Diffuse pattern more in favour of CWP or silicosis than sarcoidosis

34. HRES CTRandom High resolution CT lung ,Web - approach

36. Random nodules • Sharply define,+- feeding vessel DDX • Metastases: lung, breast, kidney, colon, melanoma, thyroid , pancreas • Infection: Milliary TB, septic emboli, fungal infection • Vasculitis • Langercellhistiocytosis

37. Metastases • Random • Basilar predominance P82, Computed Tomography of the Lung,Verschakelen

38. CT of the lung, p 75

39. Perilymphatic vs. centrilobular TB Centrilobular changes : nodules, tree-in-bud, branching lines Sarcoidosis - Fissural and subpleural nodules

40. Perilymphaticnodules. Nodules are immediately in contact with interlobular septa and the visceral pleura (B) Centrilobular nodules. Nodules are positioned 5 - 10 mm from costal and visceral pleural surfaces and interlobular septa.

41. High resolution CT lung ,Web - approach

42. References • High resolution CT of the lung, Web, Naidich • CT of the lung, Verschakelen, De Wever • Prof Naidich RSSA lecture • High-Resolution CT of the Lung: Patterns of Disease and Differential Diagnoses, RadiolClin N Am 43 (2005) 513 – 542 • Imaging of Interstitial Lung Disease, RadiolClin N Am 43 (2005) 589 – 599

43. SPN Def: focal area of increased round /oval density in the lung parenchyma measuring less than 3cm, Cause : infection, malignancy , inflammation, vascular, congenital Risk : 30-40% malignant

44. Radiographics 2000:20: 43

45. Approach to SPN • Morphology: • - Size ( smaller more likely benign) • - margins and contours

46. Internal characteristics • Homogeneous attenuation (55% benign, 20%malignant) • Pseudocavitation and air bronchograms: lymphoma or bronchioalveolar cancer • Benign cavitation : smooth ,thin walls (<4mm) • Malignant cavitation: thick irregular walls( >16mm) • Intranodular fat = hamartoma • Benign calcification : • post infection: central, diffuse solid, laminated , • hamartoma : popcorn like • Malignant calcification: diffuse,amorphous,punctate • Metastatic osteosarcoma: high attenuation nodule

47. 25-39% malignant nodules classified as benign on radiological morphology assessment • growth rate assessment: doubling rate ( increase in diameter of >26%) for malignant nodules between 30-400 days • Clinical data: age, risk factors, previous malignancy

48. Distribution of lung nodules • Cancer – basal predominance • Breast CA, Colon, Renal often metastasize to lung Interpreting CXR p100

49. Size of lung nodules • Mayo clinic CT screening trial • ( in patients with no history of cancer) • <3mm = less than 0,2% malignant • <5mm = fewer than 1% malignant • 4-7mm = 0,9% malignant • 8-20mm = 18% malignant • >20mm = 50% malignant Radiology Nov 2005 p 397

50. Follow-up National Lung Screening Trial • nodules smaller than 4mm • return for screening after 12 months, without interval scans or other work-up Radiology Nov 2005 p 397