Radiographic interpretation

RADIOGRAPHIC INTERPRETATION

Guided by:
Dr Vela Desai
Dr Beena Varma
Dr Neelkanth Patil
Dr Rajeev Sharma

Radiograph
2

 Photographic image
 Radiosensitive surface
 Radiation – X rays/ Gamma rays
 Radiogram/shadowgram/roentgenogram

11/15/2011

Role of radiographs
3

 Clinical examination phase
 Diagnosis( confirm/exclude)
 Treatment planning
 During treatment
 Follow up
 Blind screening tool-justify
 Limitations-replace clinical examination
 Need for further investigation

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Radiographs in Diagnosis
4

 Diagnostic imaging is an integral part of the
diagnostic process in clinical dentistry.
 Radiographs are often obtained as part of a

complete examination.
 Appropriate radiographic interpretation is used
along with clinical information and other tests
to formulate a differential diagnosis

Free PowerPoint Template from www.brainybetty.com 11/15/2011

Uses of radiographs
5

 Loss of tooth structure
 Caries(occlusal/proximal)
 Non carious(attrition,fracture)
 Periodontal diseases
 Endodontic diseases
 Impacted teeth
 Trauma
 Other bone pathologies
 Implants

6

 Technique Radiography
 Interpretation Radiology
 Interpretation:

Step by step analytical process that provides
an exact idea of the clinical problem and helps
to achieve the final diagnosis of any particular
lesion.

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Interpretation
7

 Three steps:
 Visualization
 Perception
 Integration of information
 Other diagnostic tools-vitality/mobility
 Pulp tester

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8

 Clinical examination  Quality assurance
 Type of radiograph  Inadequate quality
 Number of  Inadequate number
radiographs  Extraoral radiology
 Aids in interpretation  Biopsy/treatment-
aids in site selection

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FULL MOUTH INTRAORAL RADIOGRAPHS-IOPA & BITEWING

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Ideal radiograph:
 Visual : density & contrast

 Geometric : sharpness/detail,

resolution/definition, magnification, distortion
 Anatomical accuracy of radiographic images

 Adequate coverage of anatomical region of
interest.

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Viewing Conditions
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 This should be done in a quiet, darkened room
 At least two good, evenly-lit viewing boxes are
required
 A bright light illuminator is required for relatively
over-exposed areas
 Mounted in holder
 Appropriate size of viewbox to accommodate film
 Magnifying glass-detailed examination of small
regions

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12

 A radiograph is a two dimensional image of a
three dimensional object.
 Clark’s rule: The most distant object from the
cone(lingual) moves towards the direction of
the cone

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Three-dimensional concept
13

 The radiographic image is simply a
Two-dimensional shadowgram of the patient
 The third dimension must be reconstructed
mentally, preferably from two radiographic
projections made at right angles (orthogonal
projections) to each other
 Oblique projections may be required to assess
anatomically complicated areas

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Contrast perception:
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 Ability to distinguish b/w two areas of
radiographic image of diff densities-Weber’s
law
 Minimum perceptible difference in gray level is
proportional to the brightness level to which
the subject is adapted.
 All areas on a radiograph represented as:
 Black
 Grey
 White
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MACH BAND EFFECT
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 Illusion consists of light or dark stripes that are
perceived next to the boundary between two regions of
an image that have different lightness gradients

 Spatial high-boost filtering performed by the human
visual system on the luminance channel of the image
captured by the retina.

 Mach bands are independent of orientation.

 This occurs when two circles of uniform brightness are
placed side by side, separated by a sharp edge. Just
along the edge one colour looks darker than it really is,
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while the other looks lighter.

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MACH BAND EFFECT 11/15/2011

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 False-positive radiological diagnosis of dental
caries
 Manifest adjacent to metal restorations or
appliances, between enamel and dentin
 Misdiagnosis of horizontal root fractures
because of the differing radiographic
intensities of tooth and bone.

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 RADIOLUSCENT-the capability of a substance
with a relatively small atomic number to let a large
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amount of x-rays pass through it, thus producing
darkened images on x-ray films.

RADIOOPAQUE

RADIOLUSCENT

 RADIOOPACITY-the capability of a substance to
hinder or completely stop the passage of x-rays,
display as white/light areas on an exposed x-ray
film.
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Properties
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 Atomic number
 The higher the atomic number, the more
radiopaque the tissue/object:
 Physical opacity
 Air, fluid and soft tissue have approximately the
same atomic number, but the specific gravity of
air is only 0.001, whereas that of fluid and soft
tissue is 1
 Therefore air will appear black on a radiograph,
compared with fluid and soft tissue, which appear
more grey 11/15/2011

20

 Thickness
 The thicker the tissue/object, the greater the
attenuation of X-Rays and the more white the
image .

 When two tissues/objects are superimposed, the
composite shadow formed by these will appear
more opaque than either of the two separate
tissues
 Bone(14;1.8)

Image analysis
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 Identify normal anatomic landmarks
 Knowledge of normal v/s abnormal
 Attention to all regions on the film
systematically
 Three circuits

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First visual circuit: intraoral
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images
 Periapical before bitewing images
 Right maxilla to left; left mandible to right

 One anatomic structure at a time

 Eg: posterior maxilla-maxillary

sinus,tuberosity,zygomatic process
 Normal anatomy

bones, canals, foramina
Check for symmetry

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Use a systematic process
23

 Go back to the first quadrant and look at the
trabecular pattern. Is it:
 Normal

 Symmetrical when compared to the
contralateral
side
 Sparse

 Dense

 In the direction of anatomical stress

 Altered
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Fish net
Step ladder

Granular

24 TRABECULAR PATTERN 11/15/2011

Second visual circuit
25

 Examination of bone:
 Height of alveolar bone
 Crest relative to teeth
 Loss of height-more than 1.5 mm-periodontal
disease
 Cortication
 Lamina dura + PDL space + tooth roots
 Carcinoma-erosion of alveolar crest+ ill defined
borders.

26 Free PowerPoint Template from www.brainybetty.com 11/15/2011

Third visual circuit
27

 Examination of dentition & associated
structures
 Number, Sequence, appearance, root

structure
 Crowns –defective enamel, caries

 Intreproximal areas & restorations

 Pulp chambers-size, contentRestoration
Dentin
Proximal caries
 Bone-radioluscent/radioopaque lesions
Pulp

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Check individual teeth
28

 Enamel, [amelogenesis imperfecta, mulberry molar, etc.]

 The dentin, [dens invaginatus or evaginatus, denticles etc.] T

 Pulp chamber [dentinogenesis imperfecta, odontogenesis
imperfecta, odontodysplasia, taurodontism, individual obliteration of
nerve canals, etc.]

 Apical area [root resorption, lucencies or opacities]

 periodontal ligament space [widened in early osteosarcoma
(localized), scleroderma ( generalized) [ absent in
hyperparathyroidism]

 Amount of bone support.

Routine assessment of
radiographs
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 Ensure that the radiograph is the one of the patient being
examined, check the date, opd/no.
 Ensure two orthogonal projections are available.
 The radiographic views are named according to the direction the
primary beam enters and leaves the tissue and the body part
being examined
 The position of the patient during exposure should be known,
and left/right markers should be identified
 The radiograph should be of high technical quality with respect to
positioning, centring, collimation, exposure and development,
and should be free from artefacts.

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30

 Every shadow visible must be evaluated to
determine whether it is:
A feature of normal anatomy
 A composite structure formed by superimposition
of structures
 An artefact produced by inaccurate positioning

 A pathologic lesion: must be ruled out first


Interpretation is an orderly process

Normal Abnormal
variation

Developmental
Acquired
abnormalities
abnormalities

Cyst Benign Malignant Inflammatory Bone Vascular Metabolic
Trauma
neoplasia neoplasia lesion dysplasia analomy
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Why describe the lesion?
32

 The radiographic description can give us
indications of:
 Tissue of origin
 Biological behavior
 Prognosis
 Treatment concerns
 Diagnosis or a Differential Diagnosis


Describing the Lesion
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1. Size
2. Shape
3. Location
4. Density
5. Borders
6. Internal Architecture
7. Effect on adjacent structures


Aunty Minnie Approach
34

 Aunt Minny represents an abnormality which
looks like one that the evaluator has seen
before, or been told about.
 It would be difficult to recognise new findings
using this approach
Cousin Harry represents an abnormality which
the evaluator has not seen for a long time, but
would like to see
Uncle Fred represents an abnormality which is
often present

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35


Size
36

 Measure the lesion with a ruler. If you must
estimate, use surrounding structures as
guide
 Measure in two dimensions, width and
height in mm or cm

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Shape
37

Regular shapes like Round, Triangular,
Rhomboid etc.
Irregular shape like circular, fluid
filled(hydraulic)-cyst
Scalloped-multilocular app.

Odontogenic keratocyst 11/15/2011

38

Scalloped/Multilocular-
Ameloblastoma
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Location
39

 Is the lesion localized or generalized?
 Unilateral or bilateral

(submandibular fossa), fibrous dysplasia
 Where is the lesion in relation to other
structures and anatomic landmarks?
 Use terms such as:

 Mesial, Distal

 Inferior, Superior

 Posterior, Anterior

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Soft tissues or jaws:
40

 Epicentre-coronal to tooth-odontogenic
epithelium
 Epicenter of the lesion is above the
mandibular canal->odontogenic in origin
 Epicentre->below IAC->non
odontogenic(likely)
 Cartilaginous lesions, osteochondromas -
>condyles
 If the epicenter of the lesion is in the sinus, not
odontogenic in origin-alveolar process of
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maxilla

Density
41

 Is the lesion Radiopaque, Radiolucent, or
Mixed Density
 Remember that opacity is relative to the
adjacent structures.
 If the lesion is of mixed density, describe the
appearance

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Radioluscent to radioopaque
42
structures
 Air,fat,gas
 Fluid
 Soft tissue
 Bone marrow
 Trabecular bone
 Cortical bone
 Enamel
 Metal

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Internal architecture
43

 Is the lesion uniform?
 Internal structures such as septae or
loculations
 Septae –residual bone-long strands/walls
 Loculations are individual compartments(2)
 Soap bubble app- OKC
 Giant cell granuloma-wispy, granular
 Odontogenic myxoma-straight, thin
 Tooth-like elements-cementum

Fibrous dysplasia
44

 More in number
 Shorter
 Aligned in response to stress
 Randomly oriented
 Ground glass/orange peel app

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46
 Inflammatory lesion-new bone formation-thick
trabeculae-more radioopaque
 Dystrophic calcifications-damaged soft tissue
masses- calcified lymph nodes-cauliflower like
masses
 Ewing’s sarcoma-onion skin app

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Calcified lymph nodes-tuberculosis

Borders
47
 Well or poorly demarcated
 Punched out-sharp- (no bony reaction)-

multiple myeloma
 Corticated-uniform-periphery- (thin opaque border)

cyst
 Sclerotic (wide, uneven opaque border)

Periapical cemental dysplasia

 Radioluscent(periphery)+ corticated

Odontoma, cementoblastoma
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Periapical cemento Residual cyst
osseous dysplasia

Well defined borders


Ill defined borders
49

 Gradual transition-normal app bone &
abnormal app trabaculae- sclerosing osteitis

 Invasive border-bone destruction-malignancy


Jaw – examine the lesion in the
jaw:
50

· Site – location, extent, solitary, multi-focal or
generalised
· Size and shape – measure and describe. This
may require one or more views.
· Symmetry – examine contralateral site. Bilateral
symmetry is suggestive of a normal variant
· Border – sclerosis, resorption, lack of continuity
· Contents – lucent or opaque. Homogenous or
varying density
· Association with other structures. Teeth
displaced or resorbing

Effect on adjacent structures
51

 Lesions behaviour & impact on surrounding
structures-identification of disease
 Inflammatory disease-bone
resorption/formation.
 A Space Occupying lesion creates its own
space by displacing other structures, such as
teeth, maxillary sinus, inferior alveolar canal,
etc.

52

 Epicentre above crown of teeth-follicular cysts-
teeth apically
 Lesion-ramus of mandible-cherubism-anterior
direction
 Papilla of developing tooth-lymphoma
 Widening of PDL, broken lamina dura-
periapical/periodontal abscess
 Root resoption-periodontitis, trauma, tumors
 Reactive bone-periphery of lesion-benign slow
growth

53

 Inferior alveolar canal
 Superior displacement-fibrous dysplasia
 Widening of IAN-cortical boundary intact-
benign vascular/neural lesion
 Irregular widening with cortical destruction,
complete length of canal-malignant neoplasm


Outer cortical bone/periosteal
54
reactions
 Slow growing-new bone-expanding lesion-
outer cortical bone maintained
 Rapidly growing-periosteum does not respond-
missing cortical plate
 Exudate from inflammatory lesion-lift
periosteum off surface of the surface of cortical
bone-periosteum lay down new bone.
 Onion skin app-leukaemia, langerhan’s cell
histiocytosis
 Spiculated new bone-osteogenic sarcoma
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Formulation of radiographic
55
interpretation
 Organised fashion
 Single observation
 Diagnosis


56

 Decision 1: Normal V/S Abnormal
 Decision2: Developmental V/S Acquired
 Decision 3: Classification
 Decision 4: Ways To Proceed

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Decision 1: Normal V/S Abnormal
57

 Structure of interest
 Variation of normal/represents abnormality


Decision 2: Developmental V/S
Acquired
58

 Area of interest: abnormal
 Radiographic characterstics: location,
periphery, shape, internal structure, effect on
surrounding structures
 Indicates developmental/acquired-external
root resorption


Decision 3: Classification
59

 Abnormality
 Appropriate category
 Treatment plan


Decision 4: Ways To Proceed
60

 Analyse images
 Further imaging like CT, MRI
 Biopsy
 Treatment


SOFT TISSUE.
61

 The examination of the radiographic
appearance of soft tissue is all too often
overlooked.
 This is particularly true on panoramic
radiographs.
 If the clinical examination determines that soft
tissue requires radiographic examination, kVp
be reduced when the patient is exposed. Soft
tissue structures in the maxillofacial region are
often tongue, soft palate, tip and ala of the
nose Free PowerPoint Template from www.brainybetty.com 11/15/2011

Correct terminology
62

 One examines a radiograph and NOT an X-ray. Bear in mind that

an X-ray can not be seen. An X-ray is a photon / beam of energy.

 One does not see infection at the apex of a tooth. What one does

see is the well / poorly demarcated radiolucency/opacity, x mm

by y mms in size at the apex of tooth number X.

For the same reason one does not speak about a PAP in radiology.

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63

 Periodontal bone loss is not periodontitis per
se.

 Stay away from brand names. We do not
have a panorex machine here. Use the word
PANORAMIC radiograph or PAN.

 In radiologic terminology, a PA is a postero-
anterior PowerPoint Template from www.brainybetty.com
Free view. 11/15/2011

EXISTING DIAGNOSTIC
RADIOGRAPHS
64

 An effective way to reduce unnecessary
radiation to the patient is to avoid retaking
[recent] radiographs that already exist. It is the
clinician's responsibility to obtain these records
from earlier health providers where possible.


The diagnostic process is far from infallible. In any
diagnostic procedure there are four possible outcomes:-
65

1. True positive: The disease is present and
correctly identified.
2. False positive: The disease was absent but
something on the radiograph convinced the
clinician that it was present.
3. True negative: No disease present and
correctly determined.
4. False negative: Disease is present but not
detected. Occurs much too often

RADIOGRAPHIC RECORDS
66

 The value of radiographs as a part of the integral
records of a patient cannot be overstated.
 Good radiograph is difficult to match with written
records and the radiograph is more indisputable than a
written statement in a court of law provided the name of
the patient is indicated as well as the date.
 However, this is not a call to expose the patient to
ionizing radiation merely for the sake of documentation.
 One may not retake radiographs for the sake of
improving one's grades. Radiographs legally must be
kept for at least 5 years; some authorities state 7 years.

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DOCUMENTATION
67

 Clear medico-legal requirement for
documentation of interpretation.
 Signed and dated radiographic report must be
written with patient's record.
 Clinically useful in treatment planning and
case presentation.


Radiographic report
68

 Patient & general information
 Imaging procedure
 Clinical information
 Findings
 Radiographic interpretation


RADIOGRAPHIC
69
PRESCRIPTION

 Licensed dentist may prescribe radiographs
 Examination appropriate radiographic
views

Maximum amount of information

Minimum amount of ionizing radiation.


70 CONCLUSION

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References
71

 White and pharoah,principles and
interpretation.IV edition,pg281-296
 W&P. Ch.14. Oral and Maxillofacial Imaging.
Farman and NortjeNeill Serman.2000
 Dr. Parish P. Sedghizadeh. Radiographic
pathology of the head and neck.
 Brocklebank L, Dental Radiology, Oxford
University Press 1997.
 Deforge DH and Colmery BH, An Atlas of
Dental Radiology, Iowa State University Press
2000

THANK YOU
72

...when you have eliminated the impossible,
whatever remains, however improbable, must
be the
truth.
Sir Arthur Conan Doyle, (Sherlock Holmes)
British mystery author & physician (1859 - 1930)

11/15/2011

Radiographic interpretation

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