the lecture explains the different patterns of HRCT and how they can diagnose different interstitial lung diseases.

1. HRCT in diagnosis of
diffuse Lung Diseases
Dr/Ahmed Bahnassy
Assistant Professor of Radiology
Qassim University

2. Technique and anatomy
 Very thin 1mm slices for chest with 10-20
mm intervals aiming at visualizing the lung
interstitium.

3. Road map to diagnosis
1. Recognize the abnormality pattern.
2. Locate it in relation to the lung and to the
SPL
3. Evaluate its effects on lung parenchyma

4. HRCT patterns
 Reticular pattern
 Nodular pattern.
 Increased lung opacity.
 Decreased lung opacity and cystic
changes

5. I-Reticular opacities
 Interlobular septal thickening:
 Causes :
1. Lymphangitic spread of
tumour (asymmetrical or
symmetrical)
2. Pulmonary edema.
3. Amyloidosis

6. Honeycombing
– Causes:
1. IPF
2. Collagen vascular diseases
(Rh.A. - scleroderma)
3. Drug related fibrosis
4. End stage Hypersensitivity
pneumonitis
5. End Stage Sarcoidosis
6. Radiation.
7. End stage ARDS

7. Traction Bronchiectasis
 Causes :  Corkscrewed bronchi
1. Non specific in IPF
intersitial
pneumonia.
2. UIP
3. Sarcoidosis.
4. Hypersensitivity
pneumonitis.
5. Radiation.
6. End stage ARDS

8. I :Lymphangitic spread of tumour

9. II-Scleroderma

10. III-IPF
 Posterior lung cysts  Prone scan

11. IV-Rheumatoid arthritis-Dilated
bronchi=fibrosis

12. II-Nodules
 Perilymphatic.
 Centrilobular.
 Random

13. A-Perilymphatic nodules
 Causes :
1. Sarcoidosis.
2. Silicosis.
3. Lymphangitic spread
of tumour.
4. Amyloidosis.
5. Lymphocytic
interstitial pneumonitis

14. I -Sarcoidosis

15. II-Lymphangitis carcinomatosis

16. B-Random nodules
causes :
1. Miliary infection
2. Haematogenous
metastasis.
3. Sarcoidosis

17. I-Miliary TB

18. II-Miliary mets

19. C-Centrilobular nodules
 causes :
1. Endobronchial spread of
infection (Bacteria, virus, TB,
mycobacterium, fungus)
2. Endobronchial spread of
tumor (BAC)
3. Hypersensitivity pneumonitis.
4. BOOP
5. Silicosis and coal miner
pneumoconiosis

20. Centrilobular nodules
I-Bronchopneumonia

21. II-Hypersensitivity pneumonitis

22. Tree – in – bud appearance
 Causes :
1. Endobronchial spread of
infection(bacteria,TB ,fungi)
2. Airway disease with
infection(CF ,bronchiectasis)
3. Mucous plugging(asthma
,ABPA)
4. BAC .

23. I-Cystic fibrosis

24. II-Air way infection

25. III-Pseudomonas
bronchopneumonia

27. III-Increased lung opacity
 Consolidation.
 Ground Glass
opacification

28. Consolidation causes.
 Acute Symptoms:  Chronic Symptoms :
– Pneumonia – Chronic eosinophilic
– Pulmonary edema,He. pneumonia
– ARDS – BOOP
– Interstitial pneumonia
– Lipoid pneumonia.
– BAC

29. Consolidation-I-Chronic
eosinophilic pneumonia:
multifocal,patchy subpleural areas
of consolidation

30. II-BOOP:patchy GG opacity in
peribronchial distribution. (Here post
transplant graft versus host disease)

31. Ground Glass Opacity causes
 Acute Symptoms :  Chronic Symptoms :
– Pulmonary edema, – NSIP
He. – UIP
– Pneumonia. – DIP
– DAD – Hypersensitivity
– AIP pneumonitis.
– Acute Hypersensitivity – Alveolar proteinosis.
pneumonitis. – Sarcoidosis.
– Lipoid pneumonia.
– BAC

32. I-Pulmonary edema

33. II-CMV infection:GG opacities with
centrilobular nodules

34. III-Pneumocystis carinii infection

35. IV-Hypersensitivity pneumonitis

36. Crazy-paving pattern
 Combination of GG opacity
with interlobular septal
thickening.
 Non specific.
 Causes :
 PCP , viral pneumonia
,edema , hemorrhage
,ARDS .
 If chronic lung disease it is
often :alveolar proteinosis

37. Alveolar Proteinosis
 Fine reticular pattern + GG opacity

38. IV-Decreased lung opacity and
cystic lesions .
1. Emphysema
(centrilobular
,panlobular
,paraseptal )
2. Mosaic
perfusion.
3. Air trapping .
4. Lung cysts .

39. I-Centrilobular Emphysema

40. II-Panlobular Emphysema

41. III-Paraseptal Emphysema

42. Lung cysts –causes
 Uncommon:
 Common  Lymphangioleio
causes : myomatosis.
– Bullae
– Honeycombing.
 LCH
– Pneumatocekes.  TS
– Cystic  Sjogren
bronchiectasis. syndrome.
– Cysts in  LIP
hypersensitivty
pneumonitis  Papillomatosis

43. I-Lymphangiomyomatosis

44. II-LCH

45. Mosaic appearance
 causes :
 Airway Disease:
– Large air way (CF
,Bronchiectasis)
– Small air way (BOOP
,small air way
infection ,mucous
plugging)
 Vascular diseases :
– Chronic PE
– vasculitis

46. Common Interstitial lung
diseases

47. UIP/IPF

48. Reticular opacities, traction
bronchiectasis + HC

49. NSIP=GG opacities
+reticulations

50. COP- Peribronchial consolidations-
GG opacity

51. COP=Irregular nodular opacities

52. DIP

53. LIP

55. Golden rules for HRCT
interpretation.
 Honeycombing with a basal and subpleural redominance
is highly suggestive of UIP.Lung biopsy is rarely
performed when HRCT shows these findings.
 Concentric lower lobe GG opaity without honeycombing
suggests NSIP.In a patient with collagen vascular
disease ,biopsy is uncommoly performed.
 Patchy or noular subpleural or peribronchial
consolidation is typical of COP.
 Cystic air spaces or GG opacity may represent LIP.LIP is
usually associated with other diseases.
 Diffuse or centrilobular GG opacity in a smoker is typical
of DIP or RB-ILD

56. References
 1 - HOGG JH. Chronic interstitial lung disease of unknown cause: a new classification based on
pathogenesis. A J R 1991; 156: 225-233.
 2 - BERGIN C, ROGGLI V, COBLENTZ C, CHILES C. The secondary pulmonary lobule: normal
and abnormal CT appearances. AJR 1988; 151:21-25.
 3 - WEBB WR, STEIN MG, FINKBEINER WE,JUNG GI I et coll. Normal and diseased isolated
lungs: high-resolution CT. Radiology 1988; 166: 81-87.
 4 - MURATA K, ITOH H, TODO G, KANAOKA M, NOMA S et coll. Centrilobular lesions of the
lungs: demonstration by high-resolution CT and pathologic correlation. Radiology 1986; 161: 641-
645.
 5 - REMY-JARDIN M, REMY J, GIRAUD F, WATTINNE L, GOSSELIN B. Computed tomography
assessment of ground glass opacity : Semiology and significance. J Thorac Imaging 1993; 8 :
249-264.
 6 - BRAUNER MW, GRENIER Ph, MOMPOINT D, LENOIR S, De CREMOUX H. Pulmonary
sarcoidosis: evaluation with high-resolution CT. Radiology 1989; 172: 467-471.
 7 - MULLER NL, MILLER RR, WEBB WR, EWANS KG, OSTROW DN. Fibrosing alveolitis:
Pathologic-CT correlation. Radiology 1986; 160: 585-588.
 8 - WESTCOTT JL, COLE SR. Traction bronchiectasis in end-stage pulmonary fibrosis.
Radiology 1986; 161: 665-669.
 9 - MUNK PL, MULLER NL, MILLER RR, OSTROW DN. Pulmonary lymphangitic
carcinomatosis: CT and pathologic findings. Radiology 1988; 166: 705-709.
 10 - HANSELL DM, MOSKOVIC. High resolution computed tomography in extrinsic allergic
alveolitis. Clin Radiol 1991; 43: 8-12.
 11 - MULLER NL, MILLER RR. State-of-the art: Computed tomography of chronic diffuse
infiltrative lung diseaseI Am Rev Respir Dis 1990; 142: 1206-1215.