L13 PR2

Radiologic Interpretation Part 2¹

Dr Dayea Oh OMF Radiologist

Learning Objectives²

• Reviewing the systematic approach
• Describing “lesions” considering:
  • Location
  • Borders
  • Morphology
  • Internal Architecture / Pattern
  • Effects on Adjacent Tissues
• Understanding Surgical Sieve
• Choosing next appropriate diagnostic imaging modality for further evaluation
• Knowing when to urgently refer

Systematic Approach to Interpretation³

0. Any Technical or Positional Error?

1. Address Clinical Concerns

2. Dentoalveolar

   • a) Count teeth & identify ectopic and/or impacted teeth
   • b) Dental Anomalies (Position, Shape, …)
   • c) Periodontal bone loss
   • d) Dental pathology (non-carious tooth loss, caries, fracture, periapical pathologies, etc.)

3. Maxilla and Mandible

   • a) Abnormal lucencies
   • b) Abnormal opacities
   • c) Altered trabecular pattern
   • d) Fractures
   • e) Jaw Asymmetry

4. Maxillary sinuses (esp. mucosal changes)

5. TM Joints (esp. morphological change of condyles)

6. Soft Tissues (swelling, soft tissue calcifications eg. Tonsiloliths, salivary gland stones, etc.)

7. Other sites: Spine, orbits, etc. (structural changes)

Diagnostic Framework for Jaw Lesions

Radiodensity and Localization⁴⁵

Abnormal Findings (Lesions) in the Jaws

1. Lucent? Opaque? Or Mixed?

2. Localisation

• Unilateral or Bilateral?
• Single or Multiple?
• Epicentre
  • Pericoronal / Periapical to Tooth?
  • MD Body ➝ Superior / Inferior to Mandibular Canal or Within?
  • MX ➝ Inferior or Superior to Maxillary Sinus Floor?
  • Other: MD condyle, ramus, angle, etc.

Borders and Morphology

Abnormal Findings (Lesions) in the Jaws⁶

3. Borders

• Well defined / Ill (poorly) defined
  • Well defined ⟶ Corticated, Sclerotic, etc.
• Circular, Scalloping, Irregular…

4. Morphology

• Unilocular (circular border), Multilocular, Pseudo-multilocular
• Other: circular, ovoid, triangular, …

Internal Architecture and Patterns

Abnormal Findings (Lesions) in the Jaws⁷

5. Internal Architecture / Structure (lucent lesion)

• Completely lucent?
• Septa, calcifications, tooth-like structure, etc.

6. Pattern (opaque lesion)

• Homogenous / Heterogenous
• Altered trabecular bone
• Ground glass, wheel-spoke, popcorn-like, etc.

Effects on Adjacent Structures

Abnormal Findings (Lesions) in the Jaws⁸

7. Effects on Adjacent Structures

• Teeth: lamina dura, PDL space, root, follicular space
• Mandibular Canal:
  • Displacement, compression / flattening, widening, obliteration
• Surrounding Bone:
  • Sclerosis
• Cortical plate:
  • Expansion, thinning, effacement
  • Periosteal reaction / new bone formation
    • Lamellar / Onion-skin / Hair-on-end / Sunray / Codman’s triangle, etc.
• Maxillary sinus:
  • Floor: lifting, effacement, discontinuity, remodelling, etc.
  • Other walls: discontinuity, remodelling, inward bowing, etc.

Pathological Categories and Case Examples⁹¹⁰

Artefactual	Anatomical	Anomaly	Inflammatory / Infection	Cysts / Cyst-like Lesions
Hamartoma	Benign Tumour • Odontogenic • Non-odontogenic	Idiopathic	Fibro-osseous Lesions	Malignancy
Trauma	Vascular Anomalies	Metabolic / Systemic Disease	Other (giant cell lesion, syndromes, etc.)

Developmental Anomalies¹¹

• Cleft palate (congenital)
• Always look for other anomalies, especially dental anomalies (e.g., supernumerary teeth, malformed teeth, missing teeth, etc.)

Stafne Defect

OPG¹²

• Well-defined lucency with heavily/thick corticated border

CT

• Cortical depression (often fat-filled, seldom salivary gland)
• CT review

Inflammatory and Infectious Lesions¹³¹⁴

• Lucent → Mixed lucent-sclerotic → Sclerotic
• Discontinuity/effacement of maxillary sinus floor
• Sinus locule*

Inflammatory

Cysts and Cyst-like Lesions

Radicular Cysts^15161718

• Cysts are expansile and have corticated borders.

• Corticated borders = slow growing lesion.

• Further investigation with CBCT or MDCT.

• The balloon-like “hydraulic” enlargement of a cyst in the jaws, and displacement of the adjacent inferior alveolar canal as it increases in size.

• Well-defined corticated expansile lesion centred at the apical foramen of 23, extending labially and also inferiorly over the labial aspect of the root

• Labial expansion with cortical thinning and focal effacements

• Elevated cortical floor of the left maxillary sinus

• Internal homogeneous fluid attenuation. This lesion is well contained in spite of the focal effacements of the labial cortex

CBCT / MDCT review

CBCT review

Simple Bone Cysts¹⁹

• Simple Bone Cyst: Corticated lucency. Can be mildly expansile.
• MDCT/MRI Review

Hamartomas and Odontomas

Hamartoma (Tumour-like Lesions)²⁰

• Odontoma (Compound & Complex type): amorphous mix of calcified dental tissues
• CT (CBCT or MSCT/MDCT) Review
• Refer to Surgeon

Benign Odontogenic Tumours²¹²²

• Mass effect

• Expansile features + resorption

• Original outer cortex

• Benign lesion

• Erosion of endosteal surface

• Periosteum displaced bone surface

• MDCT/MRI Review

• Refer to Surgeon

• Well-defined, expansile, multilocular lucency with thick, curved internal septa resulting in “soap bubble” appearance

• MDCT/MRI Review

• Refer to Surgeon

Benign Non-odontogenic Tumours²³²⁴

• Fusiform, expansile lucency associated with mandibular canal
• Neurofibroma (strong association with Neurofibromatosis type 1 (NF1))
• MDCT/MRI Review
• Refer to Surgeon

Idiopathic Lesions and Bone Islands²⁵

• Bone islands are also considered as hamartomas.
• Localised dense bone (often homogeneous cortical density).
• Can occur anywhere.
• Most common site: mandibular premolar-molar region.
• Various morphologies.
• Seldom resorb teeth.
• Bone islands continuous with cortical plates are termed enostosis.
• Further evaluation not required.
• Monitor with I/O or OPG (unless symptomatic).

Fibro-osseous Lesions

Cemento-osseous Dysplasia²⁶

• Florid COD: Multifocal COD involving 2 or more quadrants
• Periapical COD
• Can consider CBCT review
• Cemento-osseous Dysplasia (unifocal or multifocal)
  • Early, immature lesions are lucent
  • Late, mature lesions are opaque with a lucent rim and sclerotic borders
• Fibro-osseous

Fibrous Dysplasia²⁷

• Fibro-osseous
• Fibrous Dysplasia
• Classic ground-glass appearance
• Smooth expansion
• Heterogenous pattern; mixed hypodensity & ground-glass bone
• CBCT vs MDCT

Malignant Neoplasms²⁸

• Ill-defined borders, fast-growing, destructive, invasive (invade through path of least resistance)
• Cortical destruction + various periosteal reaction
• “Floating teeth” - loss of lamina dura
• Urgent Referral to Surgeon

Squamous Cell Carcinoma²⁹³⁰

• Squamous cell carcinoma (left maxillary sinus)
• Refer to OMF Surgeons straight away
• Urgent Referral

Metastatic and Primary Bone Cancer³¹³²

• Osteoblastic Cancer

• Metastatic cancer – primary prostate cancer (some breast cancer also)

• Urgent Referral

• Primary Bone Cancer: Osteogenic sarcoma

• Urgent Referral

Orthopantomogram Report Checklist³³

1. Identify any significant OPG error
2. Check stage of dentition (deciduous / mixed / permanent)
3. Identify any missing teeth (& supernumerary teeth, if present)
   • Are there implants in edentulous sites?
     • Comment on peri-implant crestal bone level.
   • Are there root remnants?
4. Identify any impacted or ectopic teeth
   • Location
   • Angulation
   • Morphology (both crown & root system)
   • Relationship with adjacent structures eg. Adjacent molars, mx sinus, IDC, etc.
5. Any dental anomalies? (eg. Dens invaginatus, supernumeraries, etc)
6. Identify periodontal bone loss
   • Perio-endo bony defects
   • Horizontal bone loss
   • Angular bony defects / vertical bone loss
   • Furcation involvement
7. Are there calculus deposits? Where?
8. Is there existing restorative therapy?
   • Identify any faulty restorations eg. overhang, insufficient margin
9. Identify caries including recurrent caries
10. Identify non-carious tooth loss (NCTL) eg. attrition
11. Is there existing endodontic therapy?
12. Identify periapical lucencies ie. periapical inflammatory lesions
    • Any associated root resorption, antral floor remodelling, reactive sclerosis, reactive mucosal thickening in antrum?
13. Identify any abnormal lucencies or opacities in the jaws
    • Location
    • Border and Morphology
      • Well-defined? Ill-defined?
      • Overall shape – oval, round, elongated, etc.
    • Internal architecture
    • Effects on adjacent structures
    • Surgical Sieve - Differential diagnoses if can.
14. Extragnathic structures
    • Maxillary sinuses – Symmetrical? Size? Opacity? Floor and walls intact?
    • Condyles – Symmetrical? Deformity? Remodelling? Sclerosis? Pitting? Beaking / lipping? Loose bodies?
    • Airspace
    • Cervical spine
    • Any presence of soft tissue calcifications?
      • Check submandibular region, tonsillar regions, carotid bulb region, etc.
    • Pterygomaxillary fissure
    • Orbits
15. Summary (for long reports or reports with significant pathology)
    • Further imaging required? If yes, which modality?

Further Reading and References³⁴

• Essentials of dental radiography and radiology 5th edition by Whaites, Eric; Drage, Nicholas
• White and Pharoah’s Oral radiology: principles and interpretation 8th edition By Ernest Lam
• Atlas of Oral and Maxillofacial Radiology By Bernard Koong

Footnotes

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