1

Review of Radiographic Interpretation for General and

Specialist Dentists

C Grace Petrikowski DDS, Dip Oral Rad, MSc, FRCD(C)

Huronia Maxillofacial Radiology

1867 Yonge Street, #602 4 Checkley Street, #300 Toronto, ON M4S 1Y5 Barrie, ON L4N 1W1416-440-3892 705-735-4442

drgrace@hmfr.ca

Clinical Examination

Radiographicexamination

Histopathologicalanalysis

Diagnosis

Radiographic Examination

adequate number and quality of images

entire lesion visible in one or a combination of projections

supplement panoramic projections with intraorals

two views perpendicular to each other or consider CBCT for 3D info

Entire lesion not visible but see internal bone pattern

Extent of lesion visible but lacks internal detail

Entire lesion not visible but see internal bone pattern

Extent of lesion visible but lacks internal detail

2

Image Analysis Procedure

examine the entire image

identify normal anatomy

Image Analysis Procedure

picture-matching

(“Aunt Minnie” approach)

vs

systematic analysis

“Aunt Minnie” Approach

3

Cat or lynx?

Lesion Description Overview

anatomic position and epicenter

periphery / border characteristics

shape

internal characteristics

size and number

effects on surrounding structures

Anatomic Position

localized vs generalized

unilateral vs bilateral

Md vs Mx

monostotic vs polyostotic

Location / Origin

Identify epicenter - assumes equal growth in all directions

central bony

peripheral bony – arising on periosteal surface

soft tissue

Epicenter - application

mandible: relationship to inferior alveolar canal

maxilla: origin within or outside of sinus

4

5

Periphery / Borders

well-defined

ill-defined

shape

Well-defined Periphery

corticated– thin

– thick

non-corticated but definite edge (“punched out”)

sclerotic border

soft tissue capsule

6

Origin within sinus:no cortex

Origin outside of sinus:has a cortex

Ill-defined Periphery

blending - observe transition of number and shape of trabeculae

invasive / permeative - observe bone destruction (radiolucencies)

multifocal - lesions separated by normal bone

7

Shape

regular / hydraulic (fluid-filled)

irregular

scalloped

8

Size

measure lesion size with ruler– be aware that image may be

magnified (eg. pan) or distorted

relate borders of lesion to surrounding structures– facilitates comparison later on,

regardless of image magnification

Internal Characteristics: Structure and Density

radiolucent

radiopaque

mixed

Radiolucent lesions

totally radiolucent

loculated

trabeculated

9

Radiopaque Lesions

homogenous vs non-homogenous radiopacity

– degree of radiopacity within the lesion may vary in different parts of lesion

relate degree of radiopacity of lesion to radiopacity of neighboring structures such as bone and teeth

Homogenous internal pattern

Inhomogenous internal pattern

Mixed Internal Pattern

Identify radiopaque tissue

bone

tooth

cementum-like

dystrophic calcification

Comparative Radiopacity

air / fat / gas

fluid / soft tissue

cancellous bone

cortical bone / cementum

dentin

enamel

metal

radiolucent

radiopaque

Sinus air space should be radiolucent

10

Soft Tissue Density

Effects on Surrounding Structures

teeth / lamina dura / periodontal ligament space

bone

cortical boundaries and anatomic structures

suggests lesion behavior – fast vs slow-growing

Teeth and Surrounding Structures

no effect

displacement

resorption

periodontal ligament space– widened, narrowed, missing

lamina dura

11

Widening of the Periodontal Ligament Space

determine if lamina dura still present

orthodontic tooth movement

tooth mobility

intermaxillary fixation

inflammatory disease (perio or apical)

tumor invasion

therapeutic radiation to jaw

scleroderma

Effects on Surrounding Bone

no reaction (multiple myeloma)

decalcification (inflammatory disease)

bone formation– formation of a cortex (cyst, benign

tumor)

– sclerotic border (PCD)

– diffuse sclerosis (inflammation or some metastatic lesions)

Effects on Cortical Boundaries & Anatomic Structures

medial, lateral and inferior cortex of mandible

floor of maxillary sinus

floor of nasal cavity

cortex of inferior alveolar canal

look for destruction / thinning / displacement

normal cortex

cortical outlineno longer visible

12

Elevation of Mx sinus floor

Periosteal Reaction

single line / lamination

laminated (multiple lines)

solid

spiculated

MRONJ – medication-related osteonecrosis of the jaw

13

Slowly-growing lesions

regular or irregular outline

radiolucent / radiopaque / mixed

corticated and / or definite border

expand, move teeth, resorb roots, etc.

maintain bony covering

Rapidly growing lesions

irregular outline

destroy or thin cortex

radiolucent or mixed

non-corticated, ill-defined border

look for soft tissue mass

14

Breast mets –note irregularlywidened periodontal ligament spaces

Diagnostic algorithm

Normal Abnormal

Developmental Acquired

Acquired

InflammatoryCysts

NeoplasiaVascular abnormalities

Bone dysplasiasMetabolic / endocrine

Physical / chemical

Final Interpretation or ask for help

Final Interpretation

Further imaging

PeriodicRe-evaluation

Biopsy Treatment

Common Incidental Findings –Plain Radiographs

soft tissue calcifications

radiopacities in bone

radiolucencies in bone

maxillary sinus abnormalities

TMJ abnormalities

bone pattern variations

Common Incidental Findings - CBCT

maxillary sinus abnormalities are most common, followed by ethmoid sinus

soft tissue calcifications

non-vital teeth

TMJ abnormalities

cervical spine abnormalities

other: impacted teeth, residual infection, bone pattern variations

15

Soft Tissue Calcifications in Plain Radiographs

lymph nodes

tonsils

sialolith

stylohyoid ligament calcification

calcified atheromatous plaque

Soft Tissue Calcifications in CBCT

Most common ST calcifications in CBCT:

stylohyoid ligament

tonsilloliths

carotid artery

triticeous cartilage

superior horn of thyroid cartilage

submandibular sialolith

Soft Tissue Calcifications

where is the calcification? Relate to:– cervical spine level

– hyoid bone

what shape is it?– oval, linear, circular

number: single vs multiple

unilateral vs bilateral

remember: may have >1 type of calcification

Calcified Stylohyoid Chain

several ligaments arise from the styloid process and can calcify, esp. stylohyoid ligament which attaches to lesser horn of hyoid

incidence = 1.4% - 30%, 75% bilateral

usually asymptomatic, some have symptoms due to rigid stylohyoid compressing or irritating nearby structures such as the carotid artery (stylocarotid artery syndrome) or recurrent throat pain that radiates to ear or worsens with head rotation, swallowing or moving Md (Eagle syndrome)

16

Tonsillar Calcifications

paired bilateral lymphoid tissue in lateral wall of oropharynx

dystrophic calcification associated with chronic infection - incidence up to16%

tonsilloliths may grow to large size but usually small, punctate, multiple

at level of C1-C2

asymptomatic or H/O throat irritation, foul taste, odor, otalgia

Dystrophic calcification of tonsils

C1

C2

Calcified lymph nodes

Calcified lymph nodes Carotid Artery Calcifications

most common at bifurcation of internal and external carotid artery

vascular plaques form, reducing luminal diameter

can lead to decreased oxygen to brain and increased risk of stroke

atheroma-related formation of thrombi and emboli in carotid A is most frequent cause of stroke

17

Carotid Artery Calcifications

CBCT: single or multiple “rice grains”, linear or curvilinear opacities

lateral and posterior to greater horn of hyoid

always posterior-lateral to pharyngeal air space

Carotid artery calcifications

C2

C1

Tonsil calcifications

Carotid artery calcification

C1

C2

C3

18

Right side Left side

Radiopacities in bone

dense bone island

retained tooth fragment

periapical cemento-osseous dysplasia

superimposed soft tissue calcifications

Periapical cemental dysplasia –PCD

(=Periapical cemento-osseous dysplasia –PCOD)

19

Radiolucencies in bone

cysts – especially SBC

large bone marrow space

Stafne bone cyst

Stafne bone cyst Maxillary sinus abnormalities

sinuses normally filled with air radiolucent

radiopacity due to thickened soft tissue or fluid

inflammatory disease most common: thickening of sinus mucosa or sinusitis

20

Coronal Anatomy

Source: Koenig et al. Diagnostic Imaging: Oral and Maxillofacial. Amyrsis 2012.

Uncinate process

Infundibulum

Mucositis / Mucosal Hyperplasia

thickened sinus mucosa

infectious or allergic etiology

of no clinical significance if asymptomatic

imaging: radiopaque band parallel to contour of sinus wall, non-corticated

Mucositis

Mucous Retention Cyst

not a true cyst, called “pseudocyst” because is not lined with epithelium

blockage of secretory ducts of seromucinous glands in sinus mucosa results in accumulation of secretions, causing tissue swelling

most common in Mx sinus

clinically significant if blocks sinus drainage

21

Mucous retention cyst

Acute Sinusitis

= acute inflammatory process of sinonasal mucosa ≤4 wks duration

seen in ethmoid & Mx sinuses

air-fluid level, bubbly or strandy-appearing secretions and mucosal thickening “foam on water” appearance

no expansion or reduced volume of sinuses

Chronic Sinusitis

= inflammation of sinonasal mucosa ≥12 consecutive weeks duration

often associated with allergy

mucosal thickening or ST opacification of normal-sized sinuswith thickening and sclerosis of sinus bony walls

Chronic Sinusitis

Sagittal reformat

22

Sinus Polyposis

= non-neoplastic inflammatory swelling of sinus +/- nasal mucosa that buckles to form polyps

looks like multiple ST blobs

DDx includes MRC but nasal cavity spared with MRC (MRC only occurs in sinus)

rare in children

Sinus Polyposis Sinus Polyposis

Lesion Arising From Within vs. Outside Sinus

Radicular Cyst

23

Dentigerous CystClinician Responsibility

clinician responsible for interpreting the entire image volume in a CBCT scan / look to edges of conventional images

don’t forget to look in regions outside the area of interest, especially:– neck – soft tissues, C-spine

– sinuses

– TMJ

if in doubt, consult with someone with expertise in radiographic interpretation

C Grace Petrikowski DDS, Dip Oral Rad, MSc, FRCD(C)

Huronia Maxillofacial Radiology

1867 Yonge Street, #602 4 Checkley Street, #300 Toronto, ON M4S 1Y5 Barrie, ON L4N 1W1416-440-3892 705-735-4442

info@hmfr.ca