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Ct temporal bone

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Yasha Gupta

This document discusses the anatomy seen on CT scans of the temporal bone in different planes. It provides details on key structures visible in the axial, coronal, and sagittal planes, including the semicircular canals, cochlea, facial nerve canal, ossicles, and mastoid air cells. Different anatomical compartments of the middle ear are also described based on coronal imaging. The purpose is to identify relevant anatomy, assess disease extension and surgical planning for ear procedures.

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Moderator: Dr Pankaj Kumar Presenter: Dr Yasha Gupta Department of ENT Dr Baba Saheb Ambedkar Hospital.
WHY?? • Identify anatomy • Operative planning • Risk assessment • Informed consent
Informations • Aeration • Position of dura, Facial Nerve and Vessels • Labyrinth • Extension of disease • Evidence of previous surgery
Planes of scanning  Axial  30 Degrees to anthropological base line  Parallel to lateral SCC.  Best displays inner & middle ear.  Sections parallel to the hard Palate  Coronal plane  patient head extended in prone or supine with 105 degree  plane is perpendicular to the lateral SCC  Sections are parallel to posterior wall of maxillary sinus  Saggital plane 4 105 0 30
Planes • Pöschl plane approximates the plane of the sSCC • Stenvers plane is perpendicular to both the axial plane and the Pöschl plane
AXIAL CUTS • Superior SCC • Posterior SCC • Vestibular aqueduct • IAC • Facial • LSCC
Superior SCC • Start Superiorly • Superior SCC comes into view • Seen perpendicular to long axis of temporal bone
Posterior SCC • Posterior SCC appears Parallel to Petrous temporal bone
Vestibular Aqueduct • Vestibular aqueduct Veers Ventrally Onto the posterior cranial fossa surface of Temporal bone
Ct temporal bone
Inernal Auditory Canal • It is next to appear • All structures anterior to it are cochlear • Posterior to it are vestibular
Ct temporal bone
Ct temporal bone
Lateral SCC • Signet ring appearance
Ct temporal bone
Ct temporal bone
Ossicles • Ice cream cone appearance
Ct temporal bone
• The ice-cream cone sign represents the normal appearance of the malleus and incus on an axial high-resolution CT scan (HRCT) image of the temporal bone . • The ball (scoop) of the ice cream is formed by the head of malleus and the cone is formed by the body of the incus. • The space between the ice-cream cone and the scutum is called Prussak's space.
Ct temporal bone
Cochlea • Stack of coins
Cochlear aqueduct
CORONAL
Middle Ear • Three compartments in coronal plane. • A line drawn from lower edge of the scutum to the tympanic portion of the facial nerve - epi/mesotympanum. • parallel to the floor of the external auditory canal meso/hypotympanum
Epitympanum It contains : • Head of the malleus • Malleo–incudal articulation • Body and short process of the incus, • Short process of Incus projects posteriorly towards aditus. These structures are best demonstrated on axial images.
• Tegment tympani – roof of epitympanum – barrier between middle cranial fossa and middle ear cavity. • Best evaluated on coronal images
• Posteriorly the epitympanum opens into the mastoid antrum via the aditus ad antrum; demonstrated on both the axial and coronal images
Mesotympanum • The mesotympanum contains the ossicular chain • Oval and round window • Long process of the Incus • Stapes • Handle of Malleus • Facial nerve Canal
• On coronal images the long process of incus is vertically oriented parallel to the long process of malleus, continuing as the rounded lenticular and the facet to articulate with the head of the stapes
• The stapes hub and crura are best demonstrated on axial images at the level of the oval window • The stapes footplate sits in the oval window niche and cannot always be discretely identified on CT.
Ct temporal bone

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Ct temporal bone

  • 1. Moderator: Dr Pankaj Kumar Presenter: Dr Yasha Gupta Department of ENT Dr Baba Saheb Ambedkar Hospital.
  • 2. WHY?? • Identify anatomy • Operative planning • Risk assessment • Informed consent
  • 3. Informations • Aeration • Position of dura, Facial Nerve and Vessels • Labyrinth • Extension of disease • Evidence of previous surgery
  • 4. Planes of scanning  Axial  30 Degrees to anthropological base line  Parallel to lateral SCC.  Best displays inner & middle ear.  Sections parallel to the hard Palate  Coronal plane  patient head extended in prone or supine with 105 degree  plane is perpendicular to the lateral SCC  Sections are parallel to posterior wall of maxillary sinus  Saggital plane 4 105 0 30
  • 5. Planes • Pöschl plane approximates the plane of the sSCC • Stenvers plane is perpendicular to both the axial plane and the Pöschl plane
  • 6. AXIAL CUTS • Superior SCC • Posterior SCC • Vestibular aqueduct • IAC • Facial • LSCC
  • 7. Superior SCC • Start Superiorly • Superior SCC comes into view • Seen perpendicular to long axis of temporal bone
  • 8. Posterior SCC • Posterior SCC appears Parallel to Petrous temporal bone
  • 9. Vestibular Aqueduct • Vestibular aqueduct Veers Ventrally Onto the posterior cranial fossa surface of Temporal bone
  • 11. Inernal Auditory Canal • It is next to appear • All structures anterior to it are cochlear • Posterior to it are vestibular
  • 14. Lateral SCC • Signet ring appearance
  • 17. Ossicles • Ice cream cone appearance
  • 19. • The ice-cream cone sign represents the normal appearance of the malleus and incus on an axial high-resolution CT scan (HRCT) image of the temporal bone . • The ball (scoop) of the ice cream is formed by the head of malleus and the cone is formed by the body of the incus. • The space between the ice-cream cone and the scutum is called Prussak's space.
  • 24. Middle Ear • Three compartments in coronal plane. • A line drawn from lower edge of the scutum to the tympanic portion of the facial nerve - epi/mesotympanum. • parallel to the floor of the external auditory canal meso/hypotympanum
  • 25. Epitympanum It contains : • Head of the malleus • Malleo–incudal articulation • Body and short process of the incus, • Short process of Incus projects posteriorly towards aditus. These structures are best demonstrated on axial images.
  • 26. • Tegment tympani – roof of epitympanum – barrier between middle cranial fossa and middle ear cavity. • Best evaluated on coronal images
  • 27. • Posteriorly the epitympanum opens into the mastoid antrum via the aditus ad antrum; demonstrated on both the axial and coronal images
  • 28. Mesotympanum • The mesotympanum contains the ossicular chain • Oval and round window • Long process of the Incus • Stapes • Handle of Malleus • Facial nerve Canal
  • 29. • On coronal images the long process of incus is vertically oriented parallel to the long process of malleus, continuing as the rounded lenticular and the facet to articulate with the head of the stapes
  • 30. • The stapes hub and crura are best demonstrated on axial images at the level of the oval window • The stapes footplate sits in the oval window niche and cannot always be discretely identified on CT.