Preface If not coincidence, at least it was in the same decade when endoscopic sinus surgery and computed tomography were introduced to Otolaryngologists, which have changed the approach to sinonasal problems dramatically. Probably, there are no such coincidences in the history of medicine where two new modalities of approaches appeared at the same time, to deal with the same problem and complement each other while doing so. The asset of improved visualization and magnification, available through endoscopes, has revolutionized the understanding of the pathophysiology of sinusitis, and resulted in better appreciation of the anatomy of the paranasal sinuses. However, non-invasive diagnostic endoscopy has its limits, and the deeper structures cannot be evaluated by endoscopy alone . Computed tomography, which has an ability to optimally display bone, soft tissue and air simultaneously, can not only complement endoscopic examination, it can provide a surgical road map delineating the anatomy, defining the obstructing lesions, and noting anatomic variations that may predispose to operative complications. Computed tomography has scored over plain radiographs and polytomographs as an imaging modality in this area. Even though surpassing CT's capacity to image soft tissue, MRI is less suitable as an imaging modality for evaluation of this area because of the similar signal intensities for bone and air. CT scanning has become imaging modality of choice and the cooperation required between the Radiologist and the Surgeon is mandatory for both evaluation and treatment of paranasal disorders. It is of paramount importance on the part of the Otolaryngologists to understand interpretation of CT films, Radiological anatomy of the paranasal sinuses, Anatomical variations and the pathology to complement the endoscopy findings for initial screening, surgical planning, reduce postoperative complications and to provide better results. This Presentations is prepared to help Otolaryngology colleagues to learn the Imaging/radiological aspects required for endoscopic sinus surgery.

1. Imaging for Endoscopic Sinus
Surgery
Dr. Prahlada N.B M.S (PGIMER, Chandigarh)
Karnataka ENT Hospital & Research Center,
Chitradurga, Karnataka.

2. Imaging v/s Endoscopy
V/S

3. Surgery done without imaging

4. Imaging modalities
CT Scan is choice of Imaging
Plain X-Ray CT Scan MRI

5. Patient Preparation
• Course of Antibiotics & Decongestants
• Sympathomimetic Nasal Spray 15 min before
CT procedure
• Patient to blow the nose just before procedure

6. Reading CT Films
• Coronal Images
• Mark R/L sides properly
• Read from Nasion to Sphenoid sinus
• Study following in all Sections
- Nasal Septum
- Lamina Papyracea
- Skull Base

7. Normal Anatomy

8. Coronal Section : At Nasion

9. Coronal Section : At Agger Nasi

10. Frontal Recess
Sagittal Section Coronal Section

11. Lacrimal Apparatus

12. Coronal Section : At OMC

13. Anterior Skull Base

14. Ethmoid Infundibulum
Axial Section Coronal Section

15. Middle turbinate attachements
I Part II Part III Part
Vertical Oblique Horizontal

16. Lateral Recess
Coronal Section Sagittal Section

17. Coronal Section : At Post. Ethmoid

18. Posterior Ethmoid Cells (Onodi)
Axial Section Coronal Section

19. Coronal Section : At Sphenoid

20. Axial Section : At Frontal

21. Axial Section : At Optic nerve

22. Axial Section : At Maxillary sinus

23. Anatomical Variations

24. Variations : Frontal Sinus
Coronal Section Axial Section

25. Variations : Frontal Sinus
Coronal Section Axial Section

26. Variations : Frontal Sinus
Axial Section Coronal Section

27. Variations : Frontal Cells
Type I Type II
Type III Type IV

28. Variations : Agger Nasi Cells

29. Variations : Agger Nasi Cells
Agger causing disease Large Agger Nasi cell

30. Variations : Frontal Recess

31. Variations : Anterior Skull Base
Type I Type II Type III
1 - 3 mm 4 - 7 mm 8 - 16 mm

32. Variations : Uncinate process
Medially bent Pneumatized

33. Variations : Bulla Ethmoidalis
Absent Bulla

34. Variations : Ethmoid Sinus

35. Variations : Haller’s Cells

36. Variations : Middle turbinate
Concha Paradoxic MT Interlamellar

37. Rostrum of the Sphenoid

38. Sphenoid Pneumatization types
Conchal

39. Sphenoid Pneumatization types
Presellar

40. Sphenoid Pneumatization types
Sellar

41. Variations : Sphenoid Sinus
Extensive Pterygoid
pneumatization penumatization

42. Variations : Sphenoid Sinus
Dehiscent nerves ACP penumatization

43. Variations : Sphenoid Sinus
Dehiscent Optic Nerve Dehiscent Int. Carotid.a

44. Variations : Sphenoid Sinus
Absent Septa Multiple Septae

45. Variations : Sphenoid Sinus
Septa ending on Optic Septa ending on Carotid

46. CT in Pathology

47. Acute Sinusitis
• Air Fluid level
• Mucosal thickening
• Complete opacification of the sinus

48. Chronic Sinusitis
• Ethmoid sinus is commonly involved
• Mucosal thickening
• Bone remodeling due to osteitis
• Polyposis

49. Fungal Sinusitis
• Allergic fungal sinusitis
• Sinus mycetoma
• Acute invasive fungal sinusitis
• Chronic invasive fungal sinusitis
• Chronic granulomatous fungal sinusitis

50. Allergic fungal sinusitis
• Complete opacification of multiple sinuses
• Sinus expansion & erosion of sinus wall
• High attenuation areas due to metals

51. Sinus Mycetoma
• Focal area of increased attenuation that is
created within a deseased sinus

52. Acute invasive fungal sinusitis
• Aggressive bone erosion
• Extension of disease into adjacent soft
tissues
• Intrasinus high attenuation may not be
present

53. Bening polyp
• Homogenous, well circumscribed
hypodense/isodense mass

54. AC Polyp

55. Mucocoele
• Hypodense, non-enhancing mass that fills
and expands the sinus cavity

56. Mucocoele
Frontal Sphenoid

57. Complications of FESS

58. Complication : NLD injury

59. Complication : ACF injury

60. Complication : CSF Leak

61. Complication :
Orbital Haemorrhage

62. Complication :
Medical rectus injury

63. Complication :
Pneumo-encephaloceole

64. Complication :
Optic Nerve injury

65. Complication : Haemorrhage

66. Thank you
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