CT facial 3D

Outline

• 3D
• CT (axial, coronal and sagittal planes)
• Radiography (Facial series)
• Water’s view (PA view with cephalad angulation)
• Caldwell view (PA view)
• Lateral view
• Towne’s view
• Facial trauma (Pathology/Fractures)
• Nasal fractures
• Naso-orbital-ethmoidal fractures
• Frontal sinus fractures
• Orbital fractures
• Zygomatic fractures
• Maxillary fractures
• Mandibular fractures

FACIAL 3D

ct scan

Computed Tomography (CT)

Axial

Preferredmodality for imaging of the face

• More sensitive for fracture detection
• Show significant soft tissue injury, especially the globe
• Easier to perform, quicker than complete views of plain film radiographs
• Pre-surgical planning for complex injuries
• CT can miss subtle tooth fracture along the axial plane, additional orthopanthogram may be helpful to detect tooth

Axial

CT protocol

• Axial scanning from above the frontal sinus down to below hard palate (face), and can be scanned further to include the mandible, if there is a clinical suspicion for fracture of mandible
• For helical (spiral) scanner, axial images can be reconstructed to coronal and sagittal planes without the need for direct coronal scanning
• Viewing in both bone and soft tissue windows, in 3 planes (axial, coronal and sagittal)

Coronal

3D CT

Anterior View

• *Nasofrontal suture
• **Zygomaticofrontal suture
• ***Zygomaticotemporal suture
• SOF = Superior orbital fissure
• IOF = Inferior orbital fissure

3D CT

Left Lateral View

Sagittal

Normal Anatomy

• * Nasofrontal suture
• **Zygomatico-frontal suture
• *** Zygomatico-temporal suture

Sagittal

(FACE)

3D CT Base View

Computed Tomography (CT)

Facial Anatomy

Sagittal

• Face (midface) is the region from supraorbital rims to and including maxillary alveolar process.
• Mandible, including the temporomandibular joints (TMJ), considered separate from the face.

CT Facial 3D

is a type of x-ray that allows high quality images of organs, blood vessels, and bones to be recorded in a very short amount of time. The individual CT images are then layered together to form a virtual model of the body. It is able to reveal the functionality of many of the anatomical structures in the body, in addition to structural defects, tumors, and lesions.

Materialise Interactive Medical Image Control System (MIMICS)

- is an image processing software for 3D design and modeling,

3D computerized aided design (CAD) system

- is the use of computer systems to assist in the creation, modification, analysis, or optimization of a design and used to increase the productivity of the designer, improve the quality of design

• Most common fracture of the facial bone
• Telecanthus is an indication of more severe injury, further workup including CT scan is required
• CT better depicts fx, especially frontal process of maxilla. Depressed fx of frontal process of maxilla can lead to facial deformity if left untreated
• CT should be performed if there is more than a simple nasal fracture on x-ray
• Presence of telecanthus should prompt CT workup

• NOE fractures involve the central upper face, disrupting the medial orbit, nose and ethmoid sinuses
• NOE fractures are distinguished from simple nasal fractures by Posterior disruption of medial canthal region, ethmoids and medial orbital walls
• Most common from motor vehicle collisions (MVC),
• Complications- Persistent telecanthus, Injury to lacrimal system, Nasofrontal duct impingement

Facial Trauma

• Nasal fractures
• Naso-orbital-ethmoidal fractures
• Frontal sinus fractures
• Orbital fractures
• Zygomatic fractures
• Maxillary fractures
• Mandibular fractures

• motor vehicle accidents (most common),
• Frontal sinuses drain via either nasofrontal duct located posteriomedially in the sinus or in conjunction with anterior ethmoid air cells. The nasofrontal duct, if present and fractured, can be obstructed - leading to chronic drainage complication
• Fracture potentially injures nasofrontal duct (fx involves base of frontal sinus, medial to supraorbital notch)
• Early complication: frontal sinusitis leading to meningitis, osteomyelitis, orbital abscess or brain abscess
• Late complication: mucocele, mucopyocele.

• Most common portion of orbit to sustain a fracture
• CT in axial, and coronal planes are essential to determine presence of fractures and status of intraocular muscles
• Usually associated with other complex midface fractures
• Blowout fractures- Bone is displaced away from the orbit.

• Two types of zygomatic fractures-
• Zygomatic complex fracture & Isolated zygomatic arch fracture

Types of maxillary fractures

• Maxillary sagittal fracture (maxillary sinus fracture)- Fracture of a maxilla in sagittal plane, involving anterior-lateral wall of a maxillary sinus
• Alveolar process fracture- Fracture of any portion of the alveolar process
• LeFort Fractures- most severe fractures seen in face and associated with high energy trauma
• LeFort I fracture- Transverse (horizontal) fracture of inferior maxillae, involving maxillary sinuses (all except superior walls), lateral margin of nasal fossa, nasalseptum and pterygoid plates
• LeFort II fracture- Pyramid-shaped maxillary fracture, involving maxillary sinuses (anterior-lateral walls), inferior orbital rim, orbital floor and nasofrontal suture
• LeFort III fracture- This fracture separates calvaria (skull) from the facial bones. Most severe of all LeFort fractures.

• Mandible is a ring or arc bone which is usually difficult to break in one location. Approximately half of mandible fractures occur in multiple locations.
• Rare in children- If occurs, condyle is the most common location and Condyle is the growth center of mandible. Trauma to this area can retard growth and cause facial asymmetry

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End

Facial Series

• Can be obtained to screen for facial injury if CT is not immediately available
• If plain film identify a fracture other than a simple nasal bone fracture, further evaluation by CT is indicated
• Remember: plain film is a 2D image of a 3D object:
• Overlapping structures significantly obscure anatomic detail
• This problem is solved by standard views (to minimize overlap, allow visualization of important structures, familiarity for interpretation)

Plain Film Radiography