interpretation for general and clinical examination
TRANSCRIPT
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
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
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
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