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Orbital and Craniofacial Malformations


INTRODUCTION

Background

  • Craniofacial malformations have characteristic osseous and soft tissue features, which lead to visible deformity. In addition, these anomalies can lead to loss of normal function of hearing, swallowing, and vision.

  • These malformations frequently involve combinations of craniofacial locations.

  • Several craniofacial malformations have known genetic causes. The most common genetic abnormality involves the fibroblast growth factor.


Imaging

  • CT imaging with 3D reconstruction is the modality of choice. Although currently limited to research investigations, black bone MRI using an ultrashort TE sequence is a potential future alternative to CT.

  • Because craniofacial malformations frequently involve multiple anatomic sites, an evaluation of craniofacial malformations requires a systematic assessment of the calvarium, orbits, nose, palate, maxilla, mandible, temporal bone, and spine.

  • Once the combination of anomalies or a characteristic anomaly is identified, a diagnosis is often achieved.

  • This section illustrates the congenital and acquired orbital and craniofacial malformations and clues to the diagnosis.

CRANIOSYNOSTOSIS: OVERVIEW

Key Points

Background

  • Craniosynostosis is the premature fusion of the cranial sutures.

  • Craniosynostosis is categorized as single or multiple and syndromic or nonsyndromic. Syndromic craniosynostosis is associated with other anomalies of the face, trunk and/or extremities.

  • There is an association between craniosynostosis and intracranial hypertension, particularly in complex or syndromic craniosynostosis. However, no correlation between craniosynostosis and hydrocephalus has been established.

  • Craniosynostosis has been shown to be associated with altered brain morphology but not overall brain volume. These alteration may account for observed problems with language, attention, information processing, and visual spatial skills.

  • Etiology unknown; 15% are syndromic causes, most commonly due to FGFR, TWIST1, or MSX2 gene mutations

  • Secondary causes can include brain malformations and shunting, which lead to altered pressure exerted on the calvarium

Imaging

  • CT imaging with 3D reconstruction is the modality of choice.

  • Ultrasound has been suggested as an alternative modality but is operator dependent and requires user expertise.

  • Black Bone MRI may emerge in the future as an alternative to CT.

  • Syndromic craniosynostosis is often associated with jugular foramen stenosis, tonsillar herniation, altered venous drainage, and accessory transosseous venous drainage, which may impact surgical approach.

  • Plagiocephaly which refers to flattening of the skull is often imaged to assess for craniosynostosis but is most commonly due to positional flattening that occurs in infants from laying asymmetrically on one side of the posterior calvarium rather than fusion of a suture.

REFERENCES

  • 1. Attaya H., Thomas J., Alleman A.: Imaging of Craniosynostosis from Diagnosis through Reconstruction. Neurographics 2011; 01: pp. 121-128.
  • 2. Eley K.A., Watt-Smith S.R., Sheerin F., et. al.: Black Bone” MRI: a potential alternative to CT with three-dimensional reconstruction of the craniofacial skeleton in the diagnosis of craniosynostosis. Eur Radiol 2014; 24: pp. 2417-2426.
  • 3. Garza R.M., Khosla R.K.: Nonsyndromic craniosynostosis. Semin Plast Surg 2012; 26: pp. 53-63.

METOPIC CRANIOSYNOSTOSIS

Key Points

  • Normal fusion of the metopic suture occurs at 6 to 9 months

  • Premature fusion results in trigonocephaly +/− hypotelorism

  • Metopic craniosynostosis occurs in ~25% of nonsyndromic craniosynostosis cases

REFERENCEs

  • 1. Attaya H., Thomas J., Alleman A.: Imaging of Craniosynostosis from Diagnosis through Reconstruction. Neurographics 2011; 01: pp. 121-128.
  • 2. Garza R.M., Khosla R.K.: Nonsyndromic craniosynostosis. Semin Plast Surg 2012; 26: pp. 53-63.

SAGITTAL CRANIOSYNOSTOSIS

Key Points

  • Normal fusion of the sagittal suture occurs at ~22 years

  • Most common craniosynostosis (40% to 60% of craniosynostosis); 45% of nonsyndromic craniosynostosis; 20% of syndromic craniosynostosis

  • Results in scaphocephaly which is AP elongation and narrowed biparietal distance of the calvarium

REFERENCE

  • 1. Attaya H., Thomas J., Alleman A.: Imaging of Craniosynostosis from Diagnosis through Reconstruction. Neurographics 2011; 01: pp. 121-128.

CORONAL CRANIOSYNOSTOSIS

Key Points

  • The coronal suture normally fuses at ~24 years of age

  • Unilateral fusion: 25% of nonsyndromic craniosynostosis; results in anterior plagiocephaly, uplifted superolateral corner of the orbit (harlequin eye deformity), contralateral bulging of the frontoparietal skull, “facial twist”, and proptosis

  • Bilateral fusion: Usually syndromic (i.e., Apert, Crouzon); results in brachycephaly which is a shortening of the skull in AP dimension.

REFERENCEs

  • 1. Attaya H., Thomas J., Alleman A.: Imaging of Craniosynostosis from Diagnosis through Reconstruction. Neurographics 2011; 01: pp. 121-128.
  • 2. Garza R.M., Khosla R.K.: Nonsyndromic craniosynostosis. Semin Plast Surg 2012; 26: pp. 53-63.

LAMBDOID CRANIOSYNOSTOSIS

Key Points

  • Unilateral fusion results in posterior plagiocephaly; bilateral fusion results in brachycephaly

  • Unilateral fusion results in an ipsilateral mastoid bulge, contralateral parietal bulge, thickened ridge along the suture, and inferior displacement of the external auditory canal (EAC) which is a useful clinical finding to differentiate from positional plagiocephaly.

  • Less common than metopic, coronal, and sagittal suture craniosynostosis

  • Lambdoid suture normally fuses at ~26 years of age

REFERENCE

  • 1. Attaya H., Thomas J., Alleman A.: Imaging of Craniosynostosis from Diagnosis through Reconstruction. Neurographics 2011; 01: pp. 121-128.

CLOVERLEAF SKULL

Key Points

  • Also known as Kleeblattschadel deformity

  • Multisuture craniosynostosis (sagittal, coronal, and lambdoid), resulting in a trilobed or cloverleaf pattern

  • Associated with Apert, Crouzon, and Pfeiffer syndrome

REFERENCE

  • 1. Attaya H., Thomas J., Alleman A.: Imaging of Craniosynostosis from Diagnosis through Reconstruction. Neurographics 2011; 01: pp. 121-128.

APERT SYNDROME

Key Points

Background

  • Autosomal dominant; FGFR2 mutation

  • Varying degrees of developmental delay, mild to moderate intellectual disability

Imaging

  • Skull: Bicoronal craniosynostosis resulting in brachycephaly; may have widened metopic suture; harlequin eye deformity

  • Face: Midface hypoplasia, choanal stenosis, pyriform aperture stenosis, and cleft palate

  • Intracranial malformations: Callosal agenesis/dysgenesis, ventriculomegaly/hydrocephalus, temporal lobe dysgyria, Chiari I, and venous outflow stenosis

  • Symmetric syndactyly (fusion) of the hands and feet

  • Other anomalies: Cervical segmentation anomalies, cardiovascular, respiratory, GI, and GU anomalies

REFERENCES

  • 1. Rossi A. Pediatric Neuroradiology 1st edition. Springer-Verlag Berlin Heidelberg.
  • 2. Lowe L.H., Booth T.N., Joglar J.M., et. al.: Midface anomalies in children. Radiographics 2000; 20: pp. 907-922.

APERT SYNDROME

Fig. 12.1, Craniosynostosis : Overview skull shapes in caused by craniosynostosis with exception of positional plagiocephaly.

Fig. 12.2, Metopic Craniosynostosis . (A to F) 3D volumetric CT and axial CT images demonstrating metopic craniosynostosis characterized by early closure of the metopic suture and trigonocephaly of the frontal bone as well as potential for crowding of the frontal lobes and hypotelorism.

Fig. 12.3, Sagittal Craniosynostosis . (A to D) 3D volumetric CT images and coronal CT images demonstrating sagittal craniosynostosis with associated elongation of the calvarium called scaphocephaly.

Fig. 12.4, Coronal Craniosynostosis . (A to D) 3D volumetric and axial CT images demonstrating unilateral right coronal craniosynostosis and associated flattening of the calvarium, also known as plagiocephaly. Note the characteristic facial twist and contralateral bulging of the frontoparietal skull.

Fig. 12.5, Lambdoid Craniosynostosis . (A to D) 3D volumetric and axial CT images demonstrating left lambdoid craniosynostosis, with associated posterior plagiocephaly. Note the findings of ipsilateral mastoid bulge, contralateral parietal bulge, and inferior position of the ipsilateral ear.

Fig. 12.15, Micrognathia . (A) Sagittal T2W image of micrognathia, retrognathia, and glossoptosis in a patient with Pierre-Robin sequence. (B) Sagittal T2W fetal image in a different patient demonstrating the inferior facial angle is abnormally low measuring 39º. (C) Axial T2W fetal image demonstrating the AP diameter (dashed line) of the mandible in a patient with micrognathia.

Fig. 12.6, Cloverleaf Skull . (A to F) 3D volumetric and axial CT images demonstrating multisuture craniosynostosis resulting in a cloverleaf pattern.

Fig. 12.7, Apert Syndrome . (A and B) 3D volumetric CT images demonstrate bilateral coronal craniosynostosis and brachycephaly. (C and D) AP hand radiographs demonstrate bilateral syndactyly.

Fig. 12.8, Apert Syndrome . (A to F) Multiplanar CT images and 3D volumetric CT images demonstrating bilateral coronal craniosynostosis, brachycephaly, hypertelorism, pyriform aperture stenosis, ventriculomegaly, and Chiari I malformation. (G and H) Axial and coronal T2W fetal MR images demonstrate bilateral temporal lobe dysgyria, ventriculomegaly, and absent septum pellucidum.

Fig. 12.9, Crouzon Syndrome . (A to D) 3D volumetric CT images and multiplanar CT images hypertelorism, craniosynostosis of the metopic and coronal sutures, basilar invagination, Chiari I malformation, and nasopharynx.

Fig. 12.10, Pfeiffer Syndrome . (A and B) 3D volumetric CT images demonstrate wide metopic suture, bicoronal craniosynostosis, and areas of osseous thinning of the parietal bone. (C) Elbow radiograph demonstrating ankylosis of the elbow joint.

Fig. 12.11, Saethre Chotzen Syndrome . (A and B) 3D volumetric CT images demonstrate wide metopic suture, wide gap between the parietal bones, and bicoronal craniosynostosis. (C) Foot radiograph demonstrating cutaneous syndactyly between the second and third toes.

Fig. 12.12, Carpenter Syndrome . (A and B) 3D volumetric CT images demonstrate metopic, sagittal, and bicoronal craniosynostosis, ridging along the midline of the skull, downsloping orbits, and multiple intrasutural ossification centers in the arc-like lambdoid suture. (C) Foot radiograph demonstrating polydactyly.

Fig. 12.13, Bathrocephaly . (A to B, D to E) 3D volumetric CT images and (C, F) sagittal reformat CT in two separate patients demonstrating dorsal symmetric midline protuberance of the occipital calvarium with a persistent mendosal suture.

Fig. 12.14, Pierre-Robin . (A to D) 3D volumetric CT images and coronal and sagittal CT images demonstrate micrognathia, retrognathia, glossoptosis, and cleft palate. Low-set ears are also present.

Fig. 12.16, Hemifacial Microsomia . (A to D) 3D volumetric CT images and axial and sagittal CT images demonstrate left mandibular hypoplasia, leftward jaw angulation, left external auditory canal atresia, hypoplastic left muscles of mastication, and segmentation anomalies of the C2-C3 and C5-C6 vertebrae.

Fig. 12.17, Treacher Collins . (A to D) 3D volumetric CT images and axial CT image demonstrate bilateral mandibular and maxillary hypoplasia, retrognathia, and bilateral external auditory canal atresia.

Fig. 12.18, Cleidocranial Dysplasia . (A and B) 3D volumetric CT images demonstrate wide metopic and sagittal sutures, inverted pear-shaped calvarium, and multiple intrasutural ossicles (also known as wormian bones). (C) AP chest radiograph demonstrates absent clavicles. (D and E) 3D volumetric CT and axial CT image demonstrate delayed eruption of primary teeth and impacted supernumerary teeth. (F) AP pelvis radiograph demonstrates wide pubic symphysis.

Fig. 12.19, Morning Glory Disc Anomaly . (A) Axial T2W image demonstrating abnormal left optic disc with funnel shape disc, elevation of the adjacent retinal surface, and effaced distal optic nerve sheath. (B) Sagittal volumetric MR angiography image demonstrating left supraclinoid internal carotid artery stenosis. (C) Morning glory syndrome demonstrating the characteristic appearance with central white glial tissue, surrounding pigmentary changes, and straightened spoke-like vessels radiating from the disc. (C from Kaiser PK, Friedman NJ, Pineda R II. The Massachusetts Eye and Ear Infirmary Illustrated Manual of Ophthalmology. 5th ed. Elsevier; 2021.)

Fig. 12.20, Persistent Hyperplastic Primary Vitreous . (A) Axial T2W and (B) axial T1W+C images demonstrate small right globe with abnormal intraocular triangular and linear tissue (“martini sign”). (C and D) Ultrasound images of the globe without and with color Doppler demonstrate the persistent fetal vasculature of PHPV.

Fig. 12.21, Microphthalmia . A T2W image demonstrating small right and left globes with colobomatous cyst in the right orbit.

Fig. 12.22, Retinopathy of Prematurity . (A and B) Axial and coronal CT images demonstrate small right and left globes with dystrophic calcifications and abnormal lenses. Calcification is not a prominent feature of ROP but can be seen.

Fig. 12.23, Norrie Disease . (A) Axial T2W and (B) axial T1W+C images demonstrate bilateral PHPV as well as retinal detachments, and subretinal hemorrhagic effusions. (C) Axial T2W and (D) axial T1W images demonstrate bilateral PHPV with retinal detachments, and subretinal proteinaceous effusions.

Fig. 12.24, Radiotherapy-Related Atrophy . (A) Axial T1W, (B) coronal T2W fat saturation, and (C) sagittal T1W images demonstrate right masseter and medial pterygoid muscle atrophy, reduced height, and fatty marrow in the C3-C6 vertebral bodies and basilar invagination. (D to F) 3D volumetric CT images demonstrate the right facial atrophy and right head tilt.

Fig. 12.25, Choanal Atresia . (A) Axial CT image demonstrates narrow bilateral choana with membranous occlusions. (B) Axial CT image demonstrating left choana osseous narrowing and membranous occlusion. (C) Axial CT image demonstrating bilateral osseous choanal narrowing with membranous occlusion. (D and E) Axial and sagittal T2W fetal images demonstrate bilateral choanal atresia seen as dark signal interrupting the T2 hyperintense fluid signal in the posterior nasal cavity.

Fig. 12.26, CHARGE Syndrome . (A) Axial CT image demonstrates bilateral choanal atresia with osseous and membranous occlusion. (B) Axial CT image demonstrating right choanal atresia. (C) Axial CT image demonstrating left cochlear aperture stenosis and large vestibular aqueduct. (D) Axial T2 W image demonstrating bilateral microphthalmia and large right coloboma.

Fig. 12.27, Pyriform Aperture Stenosis . Axial CT image demonstrates narrow bilateral pyriform apertures.

CROUZON SYNDROME

Key Points

Background

  • Also known as craniofacial dysostosis

  • Autosomal dominant. FGRF2 gene mutation;normal intelligence

Imaging

  • Skull: Multiple craniosynostosis combinations can be seen resulting in turricephaly, trigonocephaly, brachycephaly, scaphocephaly, and cloverleaf skull

  • Face: Hypertelorism, shallow orbits, proptosis, maxillary hypoplasia, prognathia, basilar kyphosis, AP narrowing of the nasopharynx, stenosis or atresia of EAC, and cleft palate

  • Intracranial malformations: midline anomalies including callosal agenesis/dysgenesis, Chiari I, hydrocephalus, venous outflow stenosis/anomalous drainage

  • Additional anomalies: Cervical segmentation anomalies, stylohyoid ligament calcification, musculoskeletal deformities, and skin lesions

  • Normal hands and feet

REFERENCES

  • 1. Rossi A. Pediatric Neuroradiology 1st edition. Springer-Verlag Berlin Heidelberg.
  • 2. Lowe L.H., Booth T.N., Joglar J.M., et. al.: Midface anomalies in children. Radiographics 2000; 20: pp. 907-922.

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