RADIOGRAPHIC INTERPRETATION OF INFECTION & TRAUMA

Diagnostic imaging of maxillofacial and fascial space infections Anatomical extent of the process Surgically drainable abscesses and

fluid collections Demonstrating and assessing

associated complications

Plain film examination

• Periapical X ray• Panoramic radiograph : odntogentic

infection• Anteroposterior and lateral view : cervical soft tissue (airway)

submandibular, parapharyngeal, retropharyngeal space (airway compromise)

Periapical X ray

Abscess adjacent to primary tooth

Anatomic location

Caries and periapical lesion

牙周病 除了牙周病外，尚有何種疾病 ?

pericoronitis

Preoperative clinical aspects. Proptotic left globe, periorbital swelling preventing spontaneous opening of the eye, subconjunctival ecchymosis, and impairment of ocular motility to the right side

CT scan in axial view. Maxillary sinus filled with pus. Close relationship between upper molar root apexes and maxillary sinus (C). Intraoral view of residual root of tooth #26 affected by extensive carious lesion (D).

Sinusitis

Upper molars

Sinusitis (water’s view)

Prevertebral Space Infection(lateral view)

X-ray neck P.A. View : Showing severe acute deviation of trachea to Rt. side

Computed tomograph

3-dimensional picture

Gray scales :more negative --- blackmore positive --- white

CT readily assess the integrity of cortical bone

Short time required for CT examination

Relative low cost compared to MRI

Computed tomograph

CT numbers : Hounsfield units(HU)

Air : -1000 HU Fat : -80 to -100

HU Water : 0 HU Blood : 60 to 110

HU Bone : 1000 HU

• (A) Sublingual space (long black

arrow), submandibular space (long white arrow), mylohyoid muscle (star), hyoglossus muscle (black arrowhead). The root of the tongue is identified by the genioglossus (black circle) and the lingual septum (white arrowhead).

The lateral boundary of the submandibular space is formed by the fascial layers on the medial margin of the platysma muscle (dashed white arrow).

• (C) Inset: schematic of coronal plane through the oral cavity. The shaded purple area illustrates the horseshoe shaped configuration of the submandibular space and the bilateral continuity of the space ventral to the mylohyoid and anterior belly of the digastric muscles.

• (B) Coronal CT view at the level of the oral cavity. Sublingual space (long black arrow), submandibular space (long white arrow), mylohyoid muscle (star), genioglossus (black circle), and the lingual septum (white arrowhead), platysma muscle (dashed white arrow), buccinator muscle (curved arrow).

• Schematic diagram of the relationship of the tooth roots to the sublingual, submandibular, and buccal spaces. Infection extending through the lingual cortex from premolar and molar teeth will involve the sublingual space, whereas infection from molar teeth will involve the submandibular space.

• Submandibular space abscess or phlegmon. Axial contrast-enhanced CT (A) shows a large fluid collection within the right submandibular space (arrow), with thickening of the buccinator muscle on the lateral aspect of the mandible and stranding in the subcutaneous tissues representing myositis and cellulits respectively.

(B) Axial bone CT shows an endodontically treated (root canal) second molar root with apical periodontitis (C).

Ludwigs angina

Ludwigs angina• Acute respiratory

distress. Axial (A) and coronal (B) contrast-enhanced CTs demonstrate extensive edema and soft tissue thickening of the tongue, sublingual, and submandibular space seen clinically as angioedema, cellulitis, and hematoma. A calcification lies within the genioglossus muscle (arrow), representing either a foreign body or displaced sialolith and is the likely initiating factor.

Magnetic resonance imaging 3 D ( 以往 CT 只有 2 D) T1 image : good

anatomical detail T2 image : very

sensitive in detecting disease processes

T1 : fat, highly proteinaceous tissue

T2 : water content

MRI

Sialolithiasis• Sialolithiasis. (A) Axial

contrast-enhanced CT. Calcified sialolith in Wharton's duct at the junction of the superficial lobe with the deep lobe of the submandibular gland. (B) Axial contrast-enhanced CT from the same patient in A. The black arrow points to a thickened and enhancing wall of the dilated submandibular duct..

Sialolithiasis• (C) Contrast-enhanced

axial T1-weighted MRI of a different patient demonstrating a calcified sialolith in left Wharton's duct (arrow). (D) Axial T2 weighted MRI of the same patient in C showing the sialolith with surrounding fluid (arrow). The actual size of this stone was approximately 20% smaller than measured on the MRIs. Size inaccuracies for sialoliths generally would only affect sialoendoscopic or interventional retrieval or lithotripsy.

Radiographic interpretation trauma

Radiographic examination Presence of root fracture Degree of extrusion or intrusion Presence of preexisting periapical

disease Extent of root development Size of the pulp chamber and root canal Presence of jaw fractures Tooth fragments and foreign bodies

lodged in soft tissue

有幾處有 Fracture lines

Anatomic distribution of mandibular fracture

Maxillary fracture

Infraorbital fracture

Lateral wall fracture

Waters view

Peri-oral soft tissue avulsion and

Maxillary fractures, comminuted mandibular ramus/body fractures and bilateral condyle fractures.

Le Fort midfacial fractures

3-D CT reconstruction showing a Le Fort type 1 fracture

LeFort Fracture II

LeFort Fracture III

Zygomatic complex fracture

Zygomaticomaxillary arch Fracture

Submental-vertex view

The End