Abstract ID: IRIA -1251. Knowledge of CVJ anomalies is important as it contains vital structures...
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Transcript of Abstract ID: IRIA -1251. Knowledge of CVJ anomalies is important as it contains vital structures...
RADIOLOGICAL APPROACH TO CRANIOVERTEBRAL JUNCTION ANOMALIES
Abstract ID: IRIA -1251
Introduction
Knowledge of CVJ anomalies is important as it contains vital structures including cervicomedullary junction
To illustrate the various methods of craniometry used in diagnosing CVJ anomalies
Aims and objectives
Materials and methods
Multimodality radiological assessment of CVJ anomalies along with radiological findings in commonly encountered congenital CVJ anomalies is illustrated
CRANIOMETRY- LANDMARKS
A- nasionB-posterior pole of
hard palateC-anterior arch C1D-odontoid processE-posterior arch C1F- opisthionG- basionH- tuberculum
sellae
A
B
C D E
FG
H
A
B
C
D
E
A- tip of mastoid process
B-occipital condyle
C-odontoid process
D-axis body
E-lateral mass of atlas
CRANIOMETRY - LINES
CHAMBERLAIN’S LINE MCRAE’S LINE
Posterior margin of hard palate to opisthion( )
Normal- tip of dens less than 5mm below this line
Abnormal- in basilar invagination
Line from basion to opisthion ( ) Normal – tip of dens below this
line Abnormal-in basilar
invagination
CRANIOMETRY - LINES
MCGREGOR’S LINE WACKENHEIM’S LINE
Posterior margin of hard palate to lowest part of occipital bone
Normal- tip of dens less than 7mm below this line
Abnormal- in basilar invagination
Line extrapolated along dorsal surface of clivus
Normal – dens should be tangential or anterior to this line
Abnormal-in basilar invagination
DIGASTRIC LINE BIMASTOID LINE
Line between incisurae mastoidae ( )
Normal- 10mm above atlanto-occipital joint
Line between tips of mastoid processes ( )
Normal – intersects atlanto-occipital joint
CRANIOMETRY - LINES
CRANIOMETRY - ANGLESWELCHER BASAL ANGLE CLIVUS CANAL ANGLE
Angle at junction of nasion-tuberculum and tuberculum-basion lines
Normal- 132-140 degree Abnormal->143 degree in
platybasia
Angle at junction of Wackenheim’s line and posterior vertebral body line
Normal – 150-180degree Abnormal-<150 degree in
platybasia
ATLANTOOCCIPITAL JOINT AXIS ANGLE KLAUS INDEX
Angle formed at junction of lines along atlanto-occipital joints ( )
Normal -124-127 degree Obtuse in condyle hypoplasia
Distance between dens and tuberculum cruciate line ( )
Normal-40-41mm Basilar invagination-<30mm
CRANIOMETRY
Chamberlain’s line (palato-occipital line)
Palato–suboccipital line (McGregor line)
Foramen magnum line (McRae line)
Height of the posterior cranial fossa(Klaus Index)
Wackenhein’s clival canal line Bull’s angle (Atlanto-palatal
angle) Atlanto-temporo-
mandibularindex (Fischgold)
• Bimastoid line (Fischgold& Metzer)
• Bidigastric line (Fischgold& Metzer)
• Condylar angle (Schmidt & Fischer)
• Basal angle (Welcher)• Boogard’s angle
Lateral projection Frontal projection
Atlanto-occipital junction
Atlanto-occipital assimilation
Platybasia Basilar invagination
Occipital • Basiocciput hypoplasia• Occipital condyle
hypoplasia• Condylus tertius
Atlas• Posterior arch
anomalies• Anterior arch
anomalies
Axis• Ossiculum terminale• Os odontoideum• Odontoid aplasia
Associated conditions • Chiari malformation• Klippel Fiel syndrome
• Osteogenesis imperfecta• Achondroplasia
CONGENITAL CVJ ANOMALIES-CLASSIFICATION
Failure of segmentation of C1 and skull base
Association – C2-C3 fusion, atlantoaxial subluxation
CT coronal section showing complete atlanto-occipital assimilation on right side and incomplete atlanto-occipital assimilation on left side( )
CONGENITAL ANOMALIES-ATLANTO-OCCIPITALATLANTOOCCIPITAL
ASSIMILATION
CT sagittal section showing complete atlanto-occipital assimilation( ),short clivus( ),violation of Chamberlain’s line( )-basilar invagination and atlantoaxial dislocation( )
Skull base flattening Primary and secondary Bow string deformity Increased basal angle Decreased clivus canal
angle ( ) Association – basilar
invagination
32 year old gentleman with decreased clivus canal angle( ) , violation of Chamberlain’s line( , ) acute angulation, compression of cervicomedullary juncion ( )
PLATYBASIA
Abnormally high vertebral column
Prolapse into skull base Secondary- basilar
impression Chamberlain’s line Mc Gregor’s line Digastric line
24 year old gentleman with violation of Chamberlain’s line( ) and digastric line( ), atlantoaxial dislocation(atlantodens interval-3.8mm)
BASILAR INVAGINATION
CONGENITAL ANOMALIES-OCCIPITALBASIOCCIPUT HYPOPLASIA CLIVUS CANAL ANGLE
Shortening of clivus Violation of Chamberlain’s line Decreased clivus canal angle
Flattened condyles Widening of atlanto-occipital
joint axis angle ( ) Causes basilar invagination
CT sagittal section showing short clivus ( ), atlantooccipital assimilation ( ) and violation of Chamberlain’s line ( )
CT coronal section showing flattened occipital condyles( ) and widening of atlanto-occipital joint axis angle ( )
Third condyle Ossification remnant
at distal end of clivus Association – os
odontoideum
CT coronal section showing remnant ossification centre at distal end of clivus( )
CONGENITAL ANOMALIES – OCCIPTALCONDYLUS TERTIUS
Anterior and posterior arch anomalies Total or partial aplasia Isolated anterior arch anomalies –rare Split atlas
CT axial section showing posterior atlas arch rachischisis
CT axial section showing partial anterior arch rachischisis( ) and os odontoideum( )Hypertrophic anterior arch( ); corticated margins
Jefferson’s fractureIrregular margins ; normal anterior arch
CONGENITAL ANOMALIES-ATLAS
OS ODONTOIDEUM OSSICULUM TERMINALE
Separate odontoid process Failure of fusion of base with
body of axis
Bergmann ossicle Failure of fusion of apical
segment with base of dens
CONGENITAL ANOMALIES-AXIS
T1W MRI sagittal section showing os odnotoideum(
CT sagittal section showing os odnotoideum( ) with ossiculum terminale( )
KLIPPEL FIEL SYNDROME CHIARI MALFORMATION
Complex entity causing cervicovertebral fusion
Associations- occipito-atlantoid fusion
Low lying tonsils Associations- basiocciput
hypoplasia, atlanto-occipital assimilation, platybasia
CONGENITAL SYNDROMES
16 year old lady with herniated tonsils( )Acute clivocanal angle( ),short clivus( ) and cervical cord compression
CT sagittal section showing violation of Chamberlain’s line ( ), atlantooccipital fusion( ), atlantodens interval of 3.9mm( ),fused C5-C8( )
Congenital Acquired Traumatic Atlantodens
interval 3mm - adults 5mm - children
ATLANTOAXIAL DISLOCATION
20 year old man with type 2 dens fracture(irregular margins( ) and atlantoaxial dislocation( )
47 year old lady with rheumatoid arthritis with basilar impression, sclerosis of atlantoaxial joint( ) and atlantoaxial dislocation( )
18 year old lady with TB, retropharyngeal collection( ), lytic area in dens( ) and atlantoaxial dislocation( )
38 year old lady with increased atlantodens interval( )
SPONTANEOUS
INFECTIVE RHEUMATOID ARTHRITIS TRAUMA
Understanding of the important land marks and accurate assessment of the lines and angles is crucial in the evaluation of craniovertebral junction anomalies
CONCLUSION
REFERENCES
• Wendy etal, Craniovertebral junction:Normal craniometry and congenital anomalies; Radiographics:1994:14:225-277• Goel A,Basilar invagination,Chiari malformation,syringomyelia:a review,Neurology India, 2009(3):235-246• Tassanawipas etal, magnetic resonance imaging study of the craniocervical junction, J Orth surg, 2005:13(3):228-231• Harris J, The cervicocranium:its radiographic assessment, Radiology 2001;218:337-351