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Principles of Radiologic

Interpretation Accdg to White



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Objective

• To provide a step-by-step, analyticprocess that can be applied to

the interpretation of diagnosticimages

• To equip the reader with a

systematic method of imageanalysis

•

• Proficiency comes only with



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Why take a radiograph?

• If it will be useful and will affectthe treatment plan

• Re: (ICRP) Basic Principles of radiation protection: JO D

•



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Acquiring appropriatediagnostic images

• Asses the Quality of the diagnosticimage

§ Is the image distorted?§ Is the image too dark? Or too light?

§ A thorough knowledge of all possibleimage distortions is a prerequisite.

• Number and type of available images§ As indicated by the clinical examination

§ Interpretation may suggest the need foradditional imaging or views.

§ May suggest need also for images of



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Ideal viewing conditions:

1.Reduced ambient light.

2. The radiographs should be

mounted in a film mount/holder.

3.Light on viewing box should be of

equal intensity across theviewing surface.

4. The size of the viewbox should

accommodate the size of the



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Use of opaque mask (dark surround):If the viewer is much larger than the film



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Use of opaque mask (darksurround):

If the viewer is much larger than thefilm



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5.Intense light may be needed toevaluate dark areas.

6.A magnifying glass allows detailedexamination of small regions of the film.

•



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Systematic Radiographic

Examinations – Important for clinicians to establish

a systematic approach to viewing

and analyzing images— – Helps ensure recognition and

collection of all the informationcontained in the image and in

turn improves the accuracy of theinterpretation



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Analysis of Intraosseous

Lesions



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Step 1 Localize the

abnormality• Determine:

– If localized, or generalized

– The Epicenter• Point of origin (relative to the surrounding

structure) – In bone or soft tissue

– Above or below the IAN canal

– In or outside the IAN canal

– Inside or outside the tooth follicle

– At a tooth root apex

•



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Generalized

• all osseous structures of themaxillofacial region –

• consider metabolic or endocrinedisorders

• Both jaws, cranial vault, long

bones, etc•



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Localized

• – decide if

• Localized to the mandible (whichstructure) – Anterior - ramus - condylar

– Body - angle - coronoid• Localized to the maxilla

– Anterior - posterior

• unilateral or bilateral – Bilateral – may be normal anatomicvariations

– Unilateral –may be abnormal conditions



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Epicenter

• Point of origin (relative to thesurrounding structure) – In bone or soft tissue

– Above or below the IAN canal

– In or outside the IAN canal

– Inside or outside the tooth follicle – At a tooth root apex

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– Point of origin – if can bepinpointed, can indicate the

tissue type that compose theabnormality• If epicenter is coronal to the tooth

probably of odontogenicepithelium

• If above the inferior alveolar canallikely of odontogenic tissue

• If below the IAC unlikelyodontogenic tissue

•If within IAC likely neural or

vascular in nature

• If in condylar region likelycartilaginous or considerosteochondrosarcomas

• If within maxi antrum likely non



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Single or multifocal

– List of multifocalabnormalitiesshort

•



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Size

– In centimeters

– Or describing the boundaries

– E.g dentigerous cyst is often larger

than a hyperplastic follicle•



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Step 2



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Step 2Assess the Periphery and

Shape• Well defined or ill-defined? Shape?• Well defined

– If an imaginary pencil can drawconfidently the limits of the lesion

– Some small regions may be ill-defined(may be due to shape or direction of beam

– Punched out– sharp boundary, like by a paperpuncher

• Surrounding bone has normal appearance up tothe edge of the lesion

– Corticated margin- thin, fairly uniformradiopaque line of reactive bone at the periphery ;e.g. cysts

– Sclerotic margin – widen radiopaque border of reactive bone usually not uniform in width



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• Ill-defined borders

– Blending border gradual

transition between normal-appearing bone trabeculae

• Focus on trabeculae not on marrowspaces

• Eg sclerosing osteitis or fibrousdysplasia

– Invasive border associated with

rapid growth, seen usu in

malignant tumors



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• Shape, e.g.

– Circular or fluid-filled shape• Like an inflated balloon

– Scalloped shape• Series of contiguous arcs or

semicircles

• May reflect the mechanism of growth

• Seen in: cysts, cystic like lesions,some tumors

• Sometimes referred to asmultilocular**



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Analyze the Internal

Structure• Classified as: totally radiolucent e.g cysts• totally radiopaque e.g osteomas• radiolucent-radiopaque lesions

• Radiopacity may be within, in front, or

behind the lesion• List of materials from the mostradiolucent to the most radiopaque – Air, fat, and gas

– Fluid

– Soft tissue – Bone marrow

– Trabecular bone

– Cortical bone and dentin

– Enamel

– metal



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• Mixed density lesions:§ Varying trabecular patterns

different from normal bone§ Fibrous dysplasia greater innumber, shorter and randomlyoriented (not aligned in responseto stress) orange-peel or

ground glass appearance§ Stim of new bone formation

Thick trabeculae moreradiopaque

§ Septa – residual bone organizedinto long strands or walls

§ Septa divide into at least 2compartments = multilocular

§ “soap-bubble” appearance–

ameloblastoma



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§ Dystrophic calcifications§ Calci in damaged tissues

§ Eg calcified lymph nodes, appear asdense, cauliflowerlike masses

§ Cementum§ Homogenous, dense, amorphous

structure sometimes organizedinto round or oval shapes

§ Tooth structure§ Knowledge of densities of enamel,

dentin, cementum and pulp

•



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Step 4



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Step 4Analyze the Effects of the

Lesion on SurroundingStructures• Gen: displacement, resorption, etc

• Teeth, Lamina dura, periodontal

membrane space – Tooth displacement in slower

growing, space occupying lesions• Direction of epicenter impt:

– Above the crown ot tooth :displaces apically (follicular cysts,odontomas

– Start in the ramus cherubism ,

push teeth in an anterior direction

–



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• Widening of PL –Observe whether: uniform or

irregular

– Presence or absence of lamina dura

•

• Resorption –Usually more chronic andslower growing lesions

– From chronic inflammation



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• Surrounding bone density andtrabecular pattern – Presence of reactive bone (sclerotic or

corticated)

– Suggests benign growth

•

• Inferior alveolar nerve canal and mentalforamen – Superior displacement of IAC fibrous

dysplasia

– Widening of canal with maintainedcortical boundary benign lesionneural/vascular in origin

– Irregular widening with cortical

destructionàMALIGNANT NEOPLASM



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• Outer cortical bone and periostealreactions

– Cortex may remodel in response to alesion

– Slowly growing lesion new bone

formation, may maintain outer corticalplate

– Fast growing lesion outer cortical plate

may be missing

– Onion-skin type of pattern exudate

lifts off the cortical plate and then

deposits new bone• Seen more in inflammatory lesions than

malignant

– Spiculated new bone formed at right

angles to outer cortical plate•



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Step 5



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Step 5Formulate a Radiographic

Interpretation

• Decision 1: Normal vs Abnormal

• Decision 2 : Developmental vsAcquired

• Decision 3: Classification

• Decision 4: Ways to proceed• The Radiographic report



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Decision 1:

Normal vs Abnormal• Needs in-depth knowledge of

normal anatomy

Decision 2:



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Decision 2:Developmental vs.

Acquired• Analyze the location, shape,

periphery, internal structure, and

effects on surrounding tissues• E.g. When presented with tooth

with short roots, ask: “Did the

tooth develop a short root, orwas the root at one time of normal length?”

•



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Decision 3;

Classification• Select the most likely

developmental or acquired

abnormality• Rule out the more common

lesions: inflammatory or trauma,

etc• Bring clinical information into

interpretation: patient historyand clinical signs and symptoms



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Decision 4:

Ways to Proceed• Decide if data require further imaging,

treatment, biopsy, or observation of the abnormality (watchful waiting)\

• May make a short list of entities fromone of the divisions of acquiredabnormalities

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• Radiographic report may be necessaryfor: – Documentation

– Communication with other clinicians



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The Radiographic Report

• Patient and general information\ – Date, address of clinic, referring

clinician’s name, patient’s name, age,

gender, any numerical id

• Imaging procedure – List of imaging procedures taken with

date

– E.g.

• Clinical information – Ag history of present illness, any clinical

examination done prior to radiographicexam



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• Findings (observation) – Composed of an objective, detailed list of

observations, without interpretation,

made from diagnostic images – Use step-by-step analysis of lesion to

ensure completeness

• Radiographic interpretation (or

impression) – Should be shorter, and provides an

interpretation for the precedingobservations.

– One should endeavor to provide adefinitive diagnosis, but if not possible,a short list of possible conditions isacceptable.

– Advice regarding further studies, when

required, may be added.•



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self test



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• D e scrip tio n

• .Lo ca tio n

– ,T h e a b n o rm a lity is sin g u la r a n d u n ila te ra l a n d th e.e p ice n te r lie s co ro n a l to th e m a n d ib u la r first m o la r

• .Pe rip h e ry a n d sh a p e – -T h e le sio n h a s a w e ll d e fin e d cortical b o u n d a ry a n d a

.sph e rical o r ro u n d sha p e T h e p e rip h e ry a lso

.a tta ch e s to th e ce m e n to e n a m e lju n ctio n• .In te rn a l stru ctu re

– .T h e in te rn a l stru ctu re is to ta lly ra d io lu ce n t

• .E ffe cts• ,T h is le sio n h a s d isp la ce d th e first m o la r in a n a p ica l d ire ctio n

w h ich re in fo rce s th e d e cisio n th a t th e o rig in w a s co ro n a l to. ,th is to o th A lso th e le sio n h a s d isp la ce d th e se co n d m o la r

d ista lly a n d th e se co n d - .p re m o la r in a n a n te rio r d ire ctio n A p ica l

re sorp tion o f th e d ista lro ot o f th e seco n d d e cid u o u s m o la r h a s

.occurred

• T h e oc clu sal ra d iog ra p h re ve a ls th a t th e b u cca lco rtica lp la te h a s

, ,ex p an d ed in a sm oo th curve d sha p e an d a th in corticalb ou n d ary.still e x ists

Analysis



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Analysis• .T h e se im a g e s re v e a l a n a b n o rm a l a p p e a ra n ce T h e

co ro n a llo ca tio n o f th e le sio n su g g e sts th a t th e tissu e

m a kin g u p th is a b n o rm a lity p ro b a b ly is d e rive d fro m~ .a co m p o n e n t o fth d e n ta l fo llicle T h e e ffe cts o n th e

su rro u n d in g stru ctu re s in d ica te th a t th is a b n o rm a lity

.is a cq u ire d T h e d isp la ce m e n t a n d re sorp tio n o f

, , ,te e th in ta ct p e rip h e ra lco rte x cu rve d sh a p e a n d

-ra d io lu ce n t in te rn a lstru ctu re a ll in d ica te a slo w, , - ,g ro w in g b e n ig n sp a ce o ccu p y in g le sio n m o st like ly

.in th e cy st ca te g o ry

• O d o n to g e n ic tu m o rs su ch a s a n a m e lo b la stic fib ro m a ,,m a y b e co n sid e re d b u t a re le ss like ly b e ca u se o f th e

.sha p e T h e m o st com m o n typ e o f cyst in a fo llicu la r

.lo ca tio n is a fo llicu la r or d e n tig e ro u s cy st

O d o n to g e n ic ke ra to cy sts o cca sio n a lly a re se e n in th is

,lo ca tio n b u t th e to o th re sorp tio n a n d d e g re e o f

e xp a n sio n a re n o t ch a ra cte ristic o f th a t p a th o lo g ic

.co n d itio n

• ,T h e re fo re th e fin a lin te rp re ta tio n is a fo llicu la r cyst w ith



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END



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Self Test



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See pics



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