xray interpretation

criteria for diagnostic quality in interpretation principles

• appropriate modality for clinical question

• shows full region of interest

criteria of perception in interpretation principles

• ability to recognize an abnormality

• review entire image

• knowledge of normal anatomy and anatomic variation

criteria of cognition in interpretation principles

• ability to arrive at appropriate dx

• knowledge of disease mechanisms and key features

the four steps to take in overview of the interpretation principles

1. select appropriate image type

2. make sure image is of diagnostic quality

3. identify presence of any abnormalities in the image

4. determine what the abnormality is → differential dx

what is image selection

selecting the type of image that is suitable for the task to meet diagnostic objectives

the type of image selection that is suited for the diagnostic task should be guided by: (4)

• preceived by nature or severity of abnormality (size and accessibility)

• efficacy of technique to accurately reveal characteristic radiographic features of abnormality

• amount of image detail required for dx

• radiation dose; accessibility and cost to pt

what are the 4 main imaging modalities

• intraoral

• panoramic

• CBCT and MDCT

• MRI

which imaging modality has highest spatial resolution relative to other modalities in dentistry

intraoral

what is intraoral imagining best used for

evaluating disease involving teeth and supporting structures

when are PANOs indicated for dx, what is the downside

allows for examination of a larger area; lower image resolution and more artifact (than intraoral)

when is CBCT/MDCT indicated

when there is a need to evaluate anatomy in multiple dimensions without anatomical superimposition

when is MRI indicated

soft tissue evaluation

limitations to MRI compared to MDCT

MRI has more info than MDCT, but at lower resolution and hard tissues less well visualized

what are the imaging modality steps

1. clinical evaluation

2. check prior imaging

3. 2D images

4. CBCT/MDCT

5. MRI

6. nuclear medicine

when is 3D imaging indicated

if standard 2D imaging is inadequate for diagnostic task

what is a full-mouth radiographic series (FMX)

survey of whole mouth intended to display crowns and roots of all teeth, periapical areas, interproximal areas and alveolar bone including edentulous areas

limitations to periapical images

limitation to geometric distortion

BWXs are optimal for…

• revealing interproximal caries

• project the crests of the alveolar processes relative to adjacent teeth w minimal distortion

when would you use PAs instead of BWXs to evaluate caries extent and assess periodontal bone loss

when you are evaluating anterior teeth

there are a few disadvantages in PANOs, what are some

• susceptibility to pt positioning and movement

• unequal magnification and geometric distortion across image

• complex pattern of superimposition of anatomic structures challenges interpretation

• occasionally overlapping structures can hide lesions

PANO compared to intraoral…

PANO not as useful detecting small carious lesions, fine structure of periodontium, or early periapical disease

PANOs information compared to an FMX

PANO doesn’t provide much additional useful information beyond an FMX for most pts

what does it mean for a radiograph to have image quality

the reliability of an image in its representation of the true state of anatomy examined

what are the parameters of image quality (5)

• image sharpness

• spatial resolution

• contrast resolution

• magnification

• distortion

what are the 3 points in quality criteria that radiographs should have

• record the complete area of interest in the image

• have the least possible amount of magnification and distortion

• have optimal contrast and spatial resolution to facilitate interpretation for the dx task

what is the point of systematic search strategy

have a list of normal anatomic structures to look at to:

• improve detection of abnormalities

• helps avoid ‘satisfaction of search’

what is diagnostic reasoning

method of identifying features of the abnormality that will assist in arriving at a plausible interpretation or dx

in diagnostic reasoning, feature memorization is generally less effective than…

understanding basic disease mechanisms for interpretation accuracy (don’t just memorize features of disease, you should understand pathogenesis)

what are the two types of diagnostic reasonings

• non-analytical

• analytical

what is the non-analytical strategy in dx reasoning

• assumes viewing abnormality in its entirety on a global level leads to a more holistic dx hypothesis

• deliberate search for deatures that support the hypothesis → “pattern recognition”

• success is limited by experince level

what is the analytical strategy in diagnostic reasoning

• a step-by-step analysis of features which are used to make interpretation/dx

• reduces bias and premature closure of decision making process

it is best to use non-analytical and the analytical strategy together, what should you avoid in diagnostic reasoning

• avoid use of non-analytical alone

• avoid rote memorization of lesion features

what are the 2 steps in the analytical strategy

1. describe lesion features

2. interpret significance of the observed feature

what is the importance of the second step of the analytical strategy: interpret significance of the observed features

• use features to determine disease category

• narrow down to differential dx

what should your description include in the analytical strategy

• L- location

• E- edge

• S- shape/size

• I- internal content

• O- other structures

• N- number

what are the 5 steps to take in analysis of intraosseous lesions

1. localize the abnormality

2. assess periphery and shape of abnormality

3. analyze the internal structure

4. assess effects of lesion on adjacent structures

5. formulate an interpretation

what is an epicenter

geometric center of a lesion of the mesial-distal, superior-inferior, and buccal-lingual extensions

how can an epicenter help identify a lesion

may assist in determining cell or tissue type the lesion is derived from; is less accurate w very large, poorly-defined lesions

if the epicenter of a lesion is located WITHIN the IAC, what is the more likely origin of the lesion

likely neural or vascular

if there is irregular widening w cortical destruction of the IAC, what is the more likely origin of the lesion

may indicate malignant neoplasm in the canal

if the epicenter of a lesion is located ABOVE the IAC, what is the more likely origin of the lesion

likely odontogenic

if an epicenter of a lesion is located BELOW the IAC, what is the more likely origin of the lesion

likely non-odontogenic

if the epicenter of a lesion is in the ramus, coronoid, or condyle or within the maxilla sinus, what is the more likely origin of the lesion

non-odontogenic

certain lesions tend to be found in certain locations but this does NOT mean…

you should use location alone when formulating a diagnosis

how to describe a lesion extent in multiple dimensions

• peri-coronal

• peri-apical

• inter-radicular

describe the location of this lesion

in the L posterior mandible, pericoronal to #17, involving the IAC and #18

what are the 3 vocabulary words we can use to describe the periphery/border of a lesion

• well defined

• poorly defined

• zone of transition

  • narrow vs wide

what is the zone of transition

how “quickly” normal bone transitions to abnormal

do well-defined lesions tend to benign or malignant

benign

do poorly-defined lesions tend to malignant or benign

malignant

what are some terms that can be used to further describe a well-defined border

• punched out

• corticated

• sclerotic

• radiolucent periphery

what is the term punched out and what is it commonly associated w

• sharp, narrow zone of transition, non-corticated

• tends to be associated w multiple myeloma

what is the term corticated and what is it commonly associated w

• thin, radiopaque line of bone at lesion periphery

• associated w benign, slow-growing process

what is sclerotic and what is it commonly associated w

• wider, more diffuse zone of transition

• reflects ability of lesion to stimulate bone production→ reactive bone formation

what is the term radiolucent periphery and what is it commonly associated w

• rim of radiolucency representing soft tissue

• associated w benign, slow-growing lesions

• generally w outer corticated border and inner/internal radiopacity

how would describe a border that is both well-defined and kind of poorly-defined

whichever is the majority, is how the lesion will be classified

terms that can be used to define a poorly-defined lesions

• blending

• invasive

what is the term blending

• gradual, wide zone of transition

• focus on trabeculae rather than marrow spaces

what is the term invasive

• wide zone of transition w few or no trabecular between lesion periphery and normal bone→ is more focused in marrow space

• associated w rapid growth and aggressive and malignant lesions

invasive can also be called…

permeative: lesion appears to grow through trabeculae producing finger-like extensions

describe the periphery of the lesion

sclerotic, poorly-defined, blending border

what are the terms that can be used to describe size and shape of a lesion

• circular or hydraulic shape

• unilocular

• scalloping

what is circular or hydraulic shape commonly associated w

like a balloon: is a characteristic of a cyst

what is a unilocular shape

means one, corticated, single, well-defined, radiolucency

what is scalloping

series of contagious arcs or semicircles that may develop around roots of teeth or in adjacent bones or cortices

what can scalloping also be called

lobulated or loculated

what is scalloping commonly assoicated w

can be seen in cysts and benign neoplasms; may reflect mechanism of lesion growth

what are the 3 basic categories describing the internal structures of lesions

• entirely radiolucent

• entirely radiopaque

• mixed radiolucent and radiopaque

what does an entire radiolucent lesion represent

normal bone is resorbed

what does an entire radiopaque lesion represent

lesion filled w mineralized matrix

what does a mixed radiolucent and radiopaque lesions represent

clacified material is deposited against a radiolucent background

describe this lesion

lesion is periapical to #24/25, well-defined, mildly sclerotic, w mixed density of radiolucency and radiopacity

what are the types of mixed-density internal structures of lesions:

• abnormal trabecular patterns

• internal septation

• dystrophic calcification

• amorphous bone

• tooth structure

what are abnormal trabecular patterns

variations in numbers, lengths, thickness and orientations of trabeculae

is internal septation referring to unilocular or multilocular

multilocular- compartments created by septations (striations of bone within lesion)

multilocular lesions can be associated w:

• trapped, normal, residual bone

• could have been manufactured/created by lesion

• appearance of septa can indicate nature and pathogenesis of lesion

what does dystrophic calcification mean

mineralization in damaged soft tissue

what is amorphous bone

dense, often cortical-like bone, but poorly organized

why is it important to look at adjacent structures when describing a lesion

used to infer biologic behavior of a lesion

• may aid in dx

• understanding disease mechanisms that give rise to changes in required

what are some effects on adjacent structures you can note about a lesion

• displacement of teeth

• resorption of teeth

• widening of PDL

• surrounding bone rxn

• inferior alveolar canal and mental foramen

• cortical boundaries of bone

• periosteal rxn

if you see displacement of teeth from a lesion (tipping), what is this commonly associated w

benign, slower-growing, space-occupying lesions

if you see bodily displacement of a tooth/teeth, what type of lesion can this be associated w

most associated w a tumor over a cyst

if you see resorption of teeth from a lesion, what is this commonly associated w

slower-growing, benign process but may result from chronic inflammation

• some malignant tumors can occasionally resorb teeth

how can we differentiate malignancies from benign lesions when looking at the resorption of the tooth

• malignant: more likely to have thinning or “spiking” root appearance

• benign: tend to have smooth borders or resorption continuous w lesion

what should pay attention to when assessing the PDL

• observe whether widening is localized or generalized, irregular or uniform, as well as epicenter of widening

• adjacent lamina dura should also be assessed

PDL widening w epicenter at apex will imply…

source of inflammation probably from pulp → from pulp necrosis

PDL widening coronal epicenter near crest implies…

source of inflammation is probably periodontal→ periodontal disease

what can the surrounding bone rxn suggest about the lesion

abnormality can stimulate osteoblastic rxn

why is there a corticated border around a cyst

is a bone rxn that develops in response to its enlargement; is NOT part of the cyst

why is it important to evaluate the IAC and mental foramen

changes to IAC can be a characteristic of a specific disease process

why is it important to evaluate cortical boundaries

may remodel in response to lesion growth; shape and amount of expansion can provide information about the way the entity is growing and hint at the type of lesion

cortical boundaries of bone may remodel in response to lesion growth, SLOW growth of cortical boundaries allows…

time for new bone formation and expanded surface remains intact; suggests benign lesion

cortical boundaries of bone may remodel in response to lesion growth, RAPID growth of cortical boundaries will outpace…

new formation and cortex lost (eroded); suggests malignancy

if you see more erosion, less expansion, and “floating teeth” this suggests what type of lesion

an agressive, fast-growing malignancy

what are the types of periosteal rxns we can see from a lesion

• onion skin pattern

• spiculated bone pattern

• sunburst pattern

what is the onion skin pattern

layering of new bone mostly seen in inflammatory lesions and more rarely in tumors

what is spiculated bone pattern

formed at right angles to the surface cortex seen w metastatic lesions

what is a sunburst pattern

more exuberant radiating pattern of bone seen in osteosarcoma or hemangioma

what does formulate interpretation means in terms of cognition

elucidate the meaning of observations: determine the significance of observed features and combine clinical info w radiographic description

what is the interpretation algorithm (decision tree)

1. normal or abnormal

2. developmental or acquired

3. disease classification/category (if acquired)

4. ways to proceed