The document discusses the "crazy paving sign" seen on CT scans, which refers to a combination of ground glass opacity and interlobular septal thickening giving the appearance of a paved surface. Various cases are presented showing causes of this pattern including alveolar proteinosis, chronic eosinophilic pneumonia, Pneumocystis jirovecii pneumonia, bronchioloalveolar carcinoma, sarcoidosis, drug-induced lung injuries, organizing pneumonia, and lipoid pneumonia. Biopsy findings are also described for some of the cases.

1. Dr MazenQusaibatyMD, DISHead Pulmonary and Internist Department Ibnalnafisse HospitalMinistry of Syrian healthEmail: Qusaibaty@gmail.com Secondary pulmonary lobule Crazy paving sign

2. Topic Outline Secondary pulmonary lobule Crazy paving sign 2

3. Secondary pulmonary lobule 3

4. 4

5. Secondary pulmonary lobule Unit of lung (0.5-3 cm) Irregularly polyhedral 5

6. Secondary pulmonary lobule A group of terminal bronchioles 6

7. Secondary pulmonary lobule Accompanyingpulmonary arterioles 7

8. Secondary pulmonary lobule Surrounded by lymph vessels 8

9. Secondary pulmonary lobule Demarcated by “interlobular septa” 9

10. Secondary pulmonary lobule Pulmonary veins 10

11. Secondary pulmonary lobule Pulmonary lymphatics 11

12. 12 Connective Tissue Stroma

13. 13 Quiz

14. 14 Quiz

15. 15 Quiz

16. 16 Quiz

17. 17 Quiz

18. 18 Quiz

19. 19 Quiz

20. Crazy paving sign

21. Crazy paving sign Refers to the combination of ground glass attenuation superimposed on a network of interlobular septal thickening giving it an appearance of a surface paved with slabs of differing shapes 21

22. 22 Crazy paving sign Crazy Paving is a combination of ground glass opacity with superimposed net of septal thickening

23. Crazy paving sign Alveolar proteinosis 23

24. Crazy paving sign Thin-section CT scan targeted to the left upper lobe in a 41-year-old man with alveolar proteinosis 24

25. 25 Crazy Paving sign

26. 26 Crazy Paving

27. 27 Crazy Paving sign

28. 28 Crazy Paving sign

29. 29 Crazy Paving sign

30. 30 Crazy Paving sign

31. 31 Crazy Paving sign

32. 32 Crazy Paving sign

33. Causes of the crazy-paving pattern 33 http://radiographics.rsna.org/content/23/6/1509/F2.expansion.html

34. Case 01 /Crazy Paving sign Thin-section CT scan of right upper lobe 34

35. Case 01 / Crazy Paving sign A fine reticular pattern superimposed on a background of ground-glass opacity—that is, the crazy-paving pattern. 35

36. Case 01 / Crazy Paving sign Fluid within the major fissure(arrowheads) 36

37. Case 01 / Crazy Paving sign A 32-year-old man with ARDS 37

38. Case 02 / Thin-section CT scan of right lower lobe The crazy-paving pattern is present in the right lower lobe, particularly in the region circumscribed by the arrowheads 38

39. Case 02 / Crazy Paving sign The minimum and maximum sizes of each frame of the network are 2 and 6 mm, respectively. 39

40. Case 02 / Crazy Paving sign A 65-year-old woman with chronic eosinophilic pneumonia 40

41. Case 03 / Thin-section CT scan of the left lower lobe Crazy-paving appearance, which is best seen in the region circumscribed by the arrows. 41

42. Case 03 / Postmortem findings in a 41-year-old woman Alveolar Hemorrhage 42

43. Case 04 / High-resolution CT scan Areas of ground-glass attenuation with intralobular lines 43 http://radiographics.rsna.org/content/23/6/1509/F3.expansion.html

44. P carinii pneumonia in a 32-year-old man with acquired immunodeficiency syndrome. 44 http://radiographics.rsna.org/content/23/6/1509/F3.expansion.html

45. Case 04 / Photomicrograph (original magnification, ×400; Grocott stain) of a specimen obtained with bronchoalveolar lavage shows alveolar exudates that contain cystic forms of P carinii (arrows) 45 http://radiographics.rsna.org/content/23/6/1509/F4.expansion.html

46. Case 05 / Diffuse mucinous bronchioloalveolar carcinoma in a 78-year-old man / High-resolution CT scan shows a bilateral crazy-paving pattern and centrilobular nodules. 46 http://radiographics.rsna.org/content/23/6/1509/F5.expansion.html

47. Case 06 / Sarcoidosis in a 25-year-old asymptomatic man High-resolution CT scan Shows scattered bilateral areas of ground-glass attenuation associated with inter- and intralobular lines. 47 http://radiographics.rsna.org/content/23/6/1509/F11.expansion.html

48. Case 07 Methotrexate-induced NSIP in a 41-year-old woman with rheumatoid arthritis who presented with dyspnea and decreased diffusing capacity of the lungs for carbon monoxide (DLCO). 48 http://radiographics.rsna.org/content/23/6/1509/F12.expansion.html

50. Reactive hyperplastic type II pneumonocytes(arrow)49 http://radiographics.rsna.org/content/23/6/1509/F13.expansion.html

51. Case 07 / Photomicrograph (original magnification, ×400; hematoxylin-eosin stain) of a specimen from lung biopsy Findings consistent with NSIP induced by the pulmonary toxic effects of Methotrexate. 50 http://radiographics.rsna.org/content/23/6/1509/F13.expansion.html

52. Case 08 / Amiodarone-induced NSIP in an 88-year-old man with severe dyspnea High-resolution CT scan shows bilateral diffuse ground-glass attenuation and inter- and intralobular lines. Note the traction bronchiectasis. 51 http://radiographics.rsna.org/content/23/6/1509/F14.expansion.html

53. Case 09 Bleomycin induced organizing pneumonia in a 44-year-old woman with Hodgkin lymphoma who presented with: A nonproductive cough Dyspnea Decreased DLCO 52

54. Case 09 / High-resolution CT/ Bleomycin inducedBOOP Crazy-paving sign 53 http://radiographics.rsna.org/content/23/6/1509/F17.expansion.html

55. Case 09 / High-resolution CT/ Bleomycin inducedBOOP The diagnosis of was confirmed with transthoracic biopsy 54 http://radiographics.rsna.org/content/23/6/1509/F17.expansion.html

57. Initiation of corticosteroid therapy55 http://radiographics.rsna.org/content/23/6/1509/F17.expansion.html

58. Case 10 Lipoid pneumonia in a 64-year-old woman with a 20-year history of scleroderma who presented: Progressive dyspnea Dry cough 56

59. Case 10 /High-resolution CT scan/ Lipoid pneumonia Shows Crazy-paving sign(arrow) 57 http://radiographics.rsna.org/content/23/6/1509/F19.expansion.html

60. Case 10 /High-resolution CT scan/ Lipoid pneumonia The results of bronchoalveolar lavage and transbronchial biopsy were nondiagnostic 58 http://radiographics.rsna.org/content/23/6/1509/F19.expansion.html

61. Case 10 / Photomicrograph (original magnification, ×250; hematoxylin-eosin stain) of a specimen from open lung biopsy shows numerous lipid-laden macrophages that fill and distend the alveoli (arrow) and interstitium. 59 http://radiographics.rsna.org/content/23/6/1509/F20.expansion.html

62. Case 11 / Posteroanterior chest radiograph Shows a centrally located mass adjacent to an area of diffuse ground-glass opacity in the right upper lobe. Note the air trapping in the lung base. 60 http://radiographics.rsna.org/content/23/6/1509/F24.expansion.html

63. Case 11 / Posteroanterior chest radiograph CT scan shows typical crazy-paving surrounding the mass, which is perihilar. 61 http://radiographics.rsna.org/content/23/6/1509/F24.expansion.html

64. Case 11 / What diagnosis that do you expect? Adenocarcinoma BOOP. Lipoidpneumonia Diffuse pulmonary hemorrhage P carinii pneumonia 62 http://radiographics.rsna.org/content/23/6/1509/F24.expansion.html

65. Case 11 / What diagnosis that do you expect? Diffuse pulmonary hemorrhage BOOP. Lipoidpneumonia Adenocarcinoma P carinii pneumonia 63 http://radiographics.rsna.org/content/23/6/1509/F24.expansion.html

66. Case 11 / How do you explain the ground glass? Lymphangitic carcinomatosis surrounding the central mass Adenocarcinoma with surrounding pulmonary hemorrhage 64 http://radiographics.rsna.org/content/23/6/1509/F24.expansion.html

67. Case 11 / How do you explain the ground glass? Lymphangitic carcinomatosis surrounding the central mass Adenocarcinoma with surrounding pulmonary hemorrhage 65 http://radiographics.rsna.org/content/23/6/1509/F24.expansion.html