SiteSiteSize

ShapeOutline

Relative densityEffects on adjacent surrounding structures

Measuring the dimensions in cm Describing boundaries(the lesion extends from…..to…..in one dimensionand extends from…..to……in the other dimension)

Size

Shape

Monolocuar Monolocular/unilocular Multilocular Pseudoloculated Round Oval Scalloped/undulating Irregular

Pseudolocuar

Multilocuar

Smooth Punched-out Corticated: a thick or thin surrounding RO line Sclecotic: a non-uniform RO boundary Oval Encapsulated Irregular

* Well-defined Outline

Well-defined with a corticatedmargin

Well-defined without a corticated margin

Poorly-defined * Poorly-defined

Effects on adjacent surrounding structures

1. Bony expansion

1. Tooth displacement

3. Thinning of cortex

2. Displacement ID canal

1. Uniformly RL2. RL with RO (mixed)3. RO

Relative density

www.dent.ucla.edu/sod/depts/oral_rad/courses/DS422b/

Question:Please describe the lesion

as indicated by yellowish arrow

There is a well-defined unilocular round shaped circumcoronal radiolucence with corticated margin over the submerged tooth 38 extending from left retromolar area down to the mandibular angle and from distal aspect of tooth 37 up to two/thirds of left ramus area, measuring approximately 3 5 cm in diameter.

A sequential approach to radiological interpretation

Panoramic radiography revealed the patient to be fullyedentulous. All bony outlines were within the normal rangeexcept for a 4.5 x 3.0 cm well-demarcated, unilocularhomogeneous radiolucency with smooth well-corticatedoutline in the left body of the mandible.The lesion extended from the premolar region back to 1.5 cmanterior to the posterior margin of the mandibular ramus. There was slight expansion of the cortical outline of the lowerborder in the left antigonial notch region.

A sequential approach to radiological interpretation

The adjacent mandibular canal was inferiorly displaced. Canal cortical outlines were intact with no evidence of resorption and the paranasal sinuses were clear.A root fragment was noted in the region of the radiolucency in the left mandible, and there were several areas of the well-delineated radiolucency in the left mandible was that of a benign cyst or tumor.

A sequential approach to radiological interpretation

Panoramic radiography also revealed a well-delineatedradiolucency rimmed by an ovoid 3.5 x 2.5 cm calcifiedmargin, superimposed over the left mandibular ramus.The radiographic shadow of the calcified soft tissue lesionextended superiorly to the level of the mandibular sigmoidnotch and 1.5 cm below the head of the left mandibular condyle, and inferiorly to 1 cm below the left mandibular foramen and lingula

A sequential approach to radiological interpretation

The principal differential interpretations were carotid aneurysm and calcified lymph node.Although carotid bruit was not clinically detected, the risk of a carotid aneurysm mandated prompt investigation of thisradiographic finding.To elucidate further the position of this calcified soft-tissue lesion and the boundaries of the mandibular radiolucency, anaxial CT examination was performed.

Axial CTAxial CT

Maxilla

Axial CT

1st cervical vertebra

A sequential approach to radiological interpretation

The CT confirmed the presence of the calcified-rimmed softtissue ventral and lateral of the first cervical vertebral body and skull base.This was interpreted as compatible with aneurysm or psedoaneurysmal dilation of the internal carotid artery, measuring as large as 2.4 cm.Degenerative changes in the cervical spine were noted.

Axial CT

Mandible, upper portion

Axial CT

Mandible, lower portion

A sequential approach to radiological interpretation

Lower CT slices through the body of the mandible confirmedthe homogeneously radiolucent cystic lesion with a benignappearance. There was evidence of buccal and lingual corticalexpansion with attenuation.In view of the report of a probable carotid aneurysm,CT angiography was prescribed to relate this lesion to itssurrounding structures.

A sequential approach to radiological interpretationCT angiography revealed the calcified mass was intimatelyrelated to tortuous internal and external carotid arteries.Careful reformatting at various angulations failed to demonstrate a direct continuity between the internal carotid and the presumed aneurysm; however due to structural superimposition CT failed to provide a definite answer.MRI was selected to elucidate further structures obscured in the CT angiograms.

A sequential approach to radiological interpretation

MRI revealed bright signals for the carotid artery and jugular veinsbilaterally, but failed to demonstrate an aneurysm. The contents of the lesion in the left mandibular body had intermediate signal intensity

A sequential approach to radiological interpretation

Angio MaxIP MRI revealed the carotids were found to be tortuous. There was no evidence of an aneurysm of the leftinternal carotid artier.The surgeon wanted additional verification of the absence of a carotid aneurysm and ordered ultrasonography.

A sequential approach to radiological interpretation

Ultrasound images showed no evidence of aneurysm. Bothcarotid bifurcations were tortuous. There was evidence ofatherosclerotic plaque in the left and right carotid bifurcationbulbs and the proximal region of the left internal carotid artery.The systolic velocity ratio of right internal to common carotid artery was 0.59 whereas the diastolic velocity ratio was0.78; for the left side the respective ratios were 0.96 and 1.47.These ratios are within the normal range.

Neck lesion

Final Diagnosis

Mandibular lesion

A sequential approach to radiological interpretation

Glandular odontogenic cyst

The calcified lesion in the soft tissues adjacent to the firstcervical vertebra and extending to the carotid space was nota carotid aneurysm, but rather a calcifying ‘cystic’ massprobably representing a lymph node.

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