Orbital Imaging
- 1. Chairman Dr. Syed NabilBin Maruf FCPS - II Course Student NIO&H Moderator Dr. Zinat Nasrin Assistant Professor Department of Radiology NIO&H Dr. Shafiul Mostafiz Assistant Professor Fellow - Department of Oculoplasty NIO&H Imaging inOrbital Diseases
- 2. • Pair ofConfined Spaces in the Skull • Volume : 30 cc • Direct Link with Cranial Vault • Contains the Eyeballs along with other important structures Orbits
- 3. Imaging Modalities Radiography Ultrasonography Computed Tomography Magnetic Resonance Imaging
- 4. Anatomical Considerations • Size,Shape & Relations • 4 Walls, Base, Apex & Passages of Orbit • Fascial Compartments / Surgical Spaces • Contents & their Anatomy • Paranasal Sinuses
- 5. Orbital Diseases • CongenitalMalformations • Inflammatory & Infective • Vascular Lesions • Cystic Lesions & Tumours • Ocular Diseases • Orbital Trauma
- 6. Orbital Diseases Surgical Spaces •Extraorbital Space Bony Lesions & Sinus Lesions • Subperiosteal Space Subperiosteal haematoma, abscess Inflammatory & Neoplastic lesions of PNS
- 7. Orbital Diseases • Extraconallesions Capillary Haemangioma Dermoids & Epidermoids Lacrimal Gland Lesions Sarcoidosis • Tenon’s Space Extraocular extension of Choroidal Melanoma Rhabdomyosarcoma Lymphangioma Pseudotumor
- 8. Orbital Diseases • Intraconallesions Cavernous Hemangioma Optic Nerve Meningioma, Glioma, Neuritis Lymphoma Lymphangioma Pseudotumor & TED Varix CCF Metastatic Seeds Orbital Cellulitis
- 9. Orbital Imaging CT &MRI are the standard imaging CT ideal for Bony & Traumatic Manifestations MRI ideal for Soft Tissue Manifestations X-Rays can be used in limited cases B-Scan for Intra-Ocular diseases
- 10. • Most versatile,informative • Bony detail or calcification • Detect metallic foreign body • Inability to distinguish between pathological soft tissue masses which are radiologically isodense • Exposure to radiation - Cataract Computed Tomography
- 13. Computed Tomography Major Considerations •Slice thickness • Imaging plane – Axial / Coronal / Sagittal • Tissue window – Soft or Brain / Bone • Contrast enhancement – Iohexol (46% Iodine) • Modification of CT procedure • Orbit with Brain CT
- 19. • Better forsoft tissue • Not ideal to visualise Bony manifestations • Better resolution of Optic Nerve & Orbital Apex • No radiation • Must screen for metallic foreign bodies in orbit Magnetic Resonance Imaging
- 20. Magnetic Resonance Imaging BasicImage Sequences T1- weighted (T1W) • Fat appear brighter than water/vitreous/CSF T2- weighted (T2W) • Water/vitreous/CSF appear brighter than tissues like blood products
- 21. Magnetic Resonance Imaging Fluidattenuation inversion recovery (FLAIR) • Signal from fluid suppressed • Useful in demyelinating conditions as white matter hyperintensities on T2W images are better appreciated with adjacent CSF bright signals nulled
- 22. Magnetic Resonance Imaging Postcontrast images • Gadolinium-T1W Fat-suppressed images • Bright signal from intraorbital fat can mask the signal and enhancement of pathology
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- 29. Idiopathic Orbital Inflammatory Disease Enlargementof Muscle including tendon
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- 32. Optic Nerve Glioma Isodenselobulated fusiform intraconal mass along the left optic nerve
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- 34. Optic Nerve Sheath Meningioma GlobularConfiguration of Optic Nerve Sheath Meningioma with “Tram Track Sign” Fat-suppressed T1 axial (A) coronal (B) MRI, with Gadolinium
- 35. Optic Nerve Sheath Meningioma Hyperdensemass surrounding the left optic nerve with slightly lobulated contour and nerve compression
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- 38. Lacrimal Gland Tumour PleomorphicAdenoma showing rounded well- defined lacrimal gland lesion Bilateral Benign Lymphoid Hyperplasia showing oblong diffuse enlargement of the lacrimal gland
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- 44. Optic Neuritis Axial T1WAxial T1W-FLAIR Axial T1W
- 45. Angiography & Venograpy MRA/ MRV & CTA / CTV • Indicated for assessing vascular lesions: Arteriovenous Malformation Haemangioma Lymphangioma Venous Malformation Varix Arterial Aneurysm
- 46. Radiography Plain X-Ray ofthe Orbit • Very limited role • Indications: Traumatic Injuries Foreign Bodies
- 47. Radiography X-Ray Views • WatersView • Caldwell’s View • Lateral View • Submentovertex View • Rhese View
- 48. Water’s View a -Frontal sinus b - Medial Orbital Wall c - Innominate Line d - Inferior Orbital Rim e - Orbital Floor f - Maxillary Antrum g - Superior Orbital Fissure h - Zygomaticofrontal Suture i - Zygomatic Arch
- 49. Caldwell’s View a -Frontal sinus b - Innominate line c - Inferior orbital rim d - Posterior orbital floor e - Superior orbital fissure f - Greater wing of sphenoid g - Ethmoid air sinus h - Medial orbital wall i - Petrous ridge j - Zygomaticofrontal suture k - Foramen rotundum
- 50. Lateral View Orbital Roof EthmoidSinus Anterior Clinoid Process Sella Turcica Planum Sphenoidale Frontal Sinus Maxillary Sinus
- 51. Submentovertex View a -Zygomatic arch b - Orbit c - Lateral orbital wall d - Posterior wall of maxillary sinus e - Pterygoid plate f - Sphenoid sinus
- 52. Rhese View a -Right Optic Canal b - Optic Strut c - Superior Orbital Fissure d - Ethmoid Sinus e - Planum Sphenoidale f - Greater Wing of Sphenoid
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- 55. Radiography X-Ray Requisition for Intraorbital/ Intraocular Foreign Body • X-Ray (A/P) of Orbits • If Intraocular Foreign Body noted - Lateral View of Respective Side with Eyes looking Up & Down
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- 57. Ultrasonography • A- &B-Scan can play an important role in differential diagnoses of orbital masses • Site, morphology and structure of the lesion (B-scan) and on the acoustic structure, internal reflectivity, vascularization and margins of the lesion (A-scan) • Poor transmission is characteristic in any Solid, Infiltrative or Inflammatory mass of the orbit • Real-Time & Dynamic
- 58. Acoustically Abnormal Orbit MassLesion Foreign Body Inflammatory Lesion • Cellulitis • Abscess • Pseudotumour Rounded Hyper-reflective • Meningioma, Glioma • Neurofibroma Hyporeflective • Mucocele • Dermoid Cyst • Cavernous Haemangioma Irregular Hyper-reflective • Lymphoma • Metastatic Cancer Hyporeflective • Haemangioma • Lymphangioma Ultrasonography
- 59. Cornea Orbital Lymphoma Lens Retina Vitreous OpticNerve Hyper-reflective retrobulbar round solid mass
- 60. Cavernous Haemangioma • 10-MHzA & B-scan • Well encapsulated lesion • Typical hemangioma
- 61. Advanced Modalities MRI-DWI (DiffusionWeighted Imaging) MR Spectroscopy Perfusion Studies Positron Emission Tomography (PET) – CT / MRI • Can characterize lesions at molecular level • Distinguish malignant from benign • Metastatic evaluation
- 62. Conclusion • CT-Scan isthe Imaging of Choice • MRI in case of Orbital Apex, Optic Canal or Intracranial extension of Orbital Neoplasm • Coordinate with the Radiologist for best outcome • Diagnose on the basis of Clinical Correlation
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Editor's Notes
- #14 Slide Thickness • Spatial resolution of a CT depends on slice thickness. • The thinner the slice, the higher the resolution. • Usually, 2mm cuts are optimal for the eye and orbit. • In special situations (like evaluation of the orbital apex/Optic Nerve), thinner slices of 1mm/1.5mm can be more informative. Modification of CT procedure • Certain cases may require special modifications during the scanning procedure to aid diagnosis. • In a case of orbital venous varix, it is important to request for special scans (with contrast) while the patient performs a Valsalva maneuver. Simultaneous brain CT • Suspected neurocysticercosis with orbital involvement. • Head injury with orbital trauma • Optic nerve meningiomas
- #30 A&B – CT C&D – Fat supressed T1W