Category Archives: HEAD & NECK

IMAGING ANATOMY OF PHARYNX & LARYNX

IMAGING ANATOMY OF PHARYNX & LARYNX is essential to understand subsequent pathology,  The upper aerodigestive tract consists of the pharynx and the larynx. The larynx connects pharynx and trachea.

The pharynx is divided into:

Nasopharynx: extends to inferior portion of  soft palate
Oropharynx: extends from soft palate to hyoid bone
Hypopharynx (laryngeal part of the pharynx): contains pyriform sinuses and posterior pharynx.

The larynx contains:

• The laryngeal surface of epiglottis.                                                                                          • Aryepiglottic folds
• Arytenoid cartilage
• False cords
• True cords (glottis is the space between vocal cords)
• Subglottic larynx

Para-pharyngeal Space    (Fig. 1)

  • it’s Potential space filled with loose connective tissue.
  • A pyramidal Space , with the apex directed toward the lesser cornua of the hyoid bone and the base toward the skull base.
  • It Extends from skull base to mid-oropharynx.
  • BORDERS:
    Lateral: mandible, medial pterygoid muscle
    Medial: superior constrictor muscles of pharynx, tensor and levator veli palatini
    Anterior: buccinator muscle, pterygoid, mandible
    Posterior: carotid sheath.

FIG (1)
  • CONTENTS(Fig. 2)

           • Anterior (prestyloid) compartment : – Internal maxillary artery  – Interior alveolar, lingual, auriculotemporal nerves.

           • Posterior (retrostyloid) compartment:   – ICA, internal jugular vein (IJV) -CNs IX, X, XII -Cervical sympathetic chain lymph nodes.

        • Medial (retropharyngeal) compartment:  Lymph nodes (Rouvière)

FIG (2)
  • Lymphatics (Fig. 3)
    The parapharyngeal space has abundant lymph node groups.
    Lateral pharyngeal node (Rouvière)
    Deep cervical nodes
    Internal jugular chain, including jugulodigastric node
    • Chain of spinal accessory nerve
    • Chain of transverse cervical artery

FIG (3)

Paraganglia (Fig. 4)

Cells of neuroectodermal origin that are sensitive to changes in oxygen and CO2.

Types:

• Carotid body (at carotid bifurcation)
• Vagal bodies
Neoplastic transformation of the jugular bulb ganglion produces the glomus jugulare.

FIG (4)

Fluoroscopic Vocal Cord examination (Fig. 5)

Occasionallyperformedtoevaluatethesubglotticregion (Valsalva maneuver), invisible by laryngoscopy.
• Phonation of “E” during expiration: adducts cords.

• Phonation of “reversed E” during inspiration; distends laryngeal ventricles
• Puffed cheeks (modified Valsalva): distends pyriform
• Valsalva: distends subglottic region
• Inspiration: abducts cords.

FIG (5)

Nodal Stations (Fig. 6)

• IA: between anterior margins of the anterior bellies of the digastric muscles, above the
hyoid bone and below the mylohyoid muscle (submental)
• IB: below mylohyoid muscle, above hyoid bone, posterior to anterior belly of digastric muscle,
and anterior to a line drawn tangential to the posterior surface of the submandibular gland
(submandibular)
Levels II, III, IV: internal jugular nodes       II: (jugulodigastric) from skull base to lower body of the hyoid bone, through posterior edge of the sternocleidomastoid muscle and posterior edge of the submandibular gland.
Note: A node medial to the carotid artery is classified as a retropharyngeal node.
III: hyoid bone to cricoid cartilage
IV: cricoid to clavicle
Level V: skull base to clavicle, between anterior edge of trapezius muscle and posterior edge of
sternocleidomastoid muscle.

• Level VI: visceral nodes; from hyoid bone, top of manubrium, and between common carotid arteries on each side
• Level VII: caudal to top of the manubrium in superior mediastinum (superior mediastinal
nodes).

FIG (6)

Pathologic Adenopathy Size Criteria:

Neck lymphadenopathy by size has poor specificity, and no universal standard exists for determination of adenopathy. Nonetheless, two methods are commonly used:
• Long axis: 15mm in levels I and II, 10mm elsewhere
• Short axis: 11mm in level II, 10mm elsewhere Retropharyngeal nodes should not exceed 8mm
(long) or 5mm (short).

Emerging technologies such as MRI lymph node imaging with iron nanoparticles or PET may prove to be more specific and sensitive.

——————————————————————-

THANKS TO PROF.DR. Ralph Weissleder, MD, PhD

DIFFERENTIAL DIAGNOSIS OF HEAD & NECK LESIONS

DIFFERENTIAL DIAGNOSIS OF HEAD & NECK LESIONS IS VERY INTERESTING TOPIC TO DISCUSS.

Temporal Bone

  • Approach:

  • Soft tissue mass in the middle ear:

ü Cholesteatoma ü Chronic otitis media
ü Granulation tissue ü Cholesterol granuloma
ü Glomus tympanicum tumor ü Aberrant ICA
ü High or dehiscent jugular bulb ü
  • Vascular mass in middle ear:

·        Glomus tympanicum ·        Aberrant carotid artery
·        Carotid artery aneurysm ·        Persistent stapedial artery
·        Exposed jugular bulb ·        Exposed carotid artery
·        Hemangioma ·        Extensive glomus jugulare
  • Intra-canalicular IAC masses:

Exclusively intra-canalicular lesions: §  Acoustic neuroma (CN VIII), common

§  Facial neuroma (CN VII), rare

§  Hemangioma

§  Lipoma

Not primarily intra-canalicular: §  Meningioma

§  Epidermoid

 

  • Jugular fossa mass:

o   Glomus jugular tumor is the  most common

o   Neurofibroma is the  2nd most common

o   Schwannoma

o   Chondrosarcoma

o   Metastases

  • Mastoid bone defect:

ü Neoplastic bone destruction

ü Cholesteatoma

ü Post-operative simple / radical mastoidectomy

ü Post-traumatic deformity

  • Petrous apex lesions:

§  Cholesterol granuloma which appears T1 hyper-intense

§  Mucocele

   –  T1 hypo-intense

     – but may be T1 hyper-intense if à proteinaceous, then                           indistinguishable from cholesterol granuloma

§  Epidermoid àrestricted diffusion

§  Chondrosarcoma

§  Chordoma à if central extending to petrous

§  Endolymphatic sac tumor:  rare, more posterior; L > R; if bilateral, you think of VHL

ORBIT

  • Approach to orbital masses:

 

  • Orbital masses by Etiology:

Tumors: o   Hemangioma:  in adults: cavernous, in children: capillary.

o   Lymphoma

o   Metastases

o   Lymphangioma

o   Less common:

     ü Rhabdomyosarcoma

    ü Hemangiopericytoma

    ü Neurofibroma

Inflammatory: o   Pseudotumor is common

o   Thyroid ophthalmopathy is common

o   Cellulitis, abscess

o   Granulomatous is Wegener disease

Vascular: o   Carotid-cavernous fistula

o   Venous varix

o   Thrombosis of superior ophthalmic vein

Trauma: o   Hematoma

o   Foreign body

  • Extra-conal & Intra-conal Disease:

Extraconal disease Intraconal disease
Nasal disease:

·        Infection

·        Neoplasm

Orbital bone disease:

·        Subperiosteal abscess

·        Osteomyelitis

·        Fibrous dysplasia

·        Tumors

·        Trauma

Sinus disease:

·        Mucocele

·        Invasive infections

·        Neoplasm

Lacrimal gland disease:

·        Adenitis

·        Lymphoma

·        Pseudotumor

·        Tumor

Well-defined margins:

·        Hemangioma

·        Schwannoma

·        Orbital varix

·        Meningioma

Ill-defined margins:

·        Pseudotumor

·        Infection

·        Lymphoma

·        Metastases

Muscle enlargement:

·        Pseudotumor

·        Graves disease (thyroid ophthalmopathy)

·        Myositis

·        Carotid cavernous fistula

  • Vascular orbital lesions:

Tumor: ü Hemangioma, hemangioendothelioma, hemangiopericytoma

ü Lymphangioma

ü Meningioma

Vascular:

(with enlarged superior ophthalmic vein):

ü Carotid cavernous fistula

ü Cavernous thrombosis

ü Orbital varix

ü Ophthalmic artery aneurysm

  • Optic nerve sheath enlargement

Tumor o   Optic nerve glioma

o   Meningioma

o   Meningeal carcinomatosis

o   Metastases, lymphoma, leukemia

Inflammatory o   Optic neuritis

o   Pseudotumor

o   Sarcoid

increase intracranial pressure  
Trauma: o   hematoma
  • Tramtrack enhancement of orbital nerve:

§  Optic nerve meningioma

§  Optic neuritis

§  Idiopathic

§  Pseudotumor

§  Sarcoidosis

§  Leukemia, lymphoma

§  Peri-optic hemorrhage

§  Metastases

§  Normal variant

  • Third nerve palsy:

• Compression: ·        Intracranial aneurysm (do not miss)

·        Uncal herniation

·        Tumors  : neurofibroma, metastases, primary

·        Granuloma :Tolosa-Hunt, sarcoid

• Infection: ·        Encephalitis

·        Meningitis

·        Herpes zoster

• Vasculitis, dural cavernous sinus fistula
• Demyelination
• Trauma
• Infiltration (leptomeningeal carcinomatosis)
  • Ocular muscle enlargement:

o   Thyroid ophthalmopathy (most common cause); painless

o   Infection from adjacent sinus

o  Pseudotumor; painful

o   Granulomatous: TB, sarcoid, cysticercosis

o   Rare causes:

High flow: ü Dural AVM,

ü Carotid cavernous sinus fistula (CCF)

ü Lymphangioma

Hemorrhage  
Tumor: ü Lymphoma

ü Rhabdomyosarcoma

ü Leukemia

ü Metastases

Trauma  
Acromegaly  
Apical mass  
  • Overview of Orbital Masses:

Mass Children Adults
Tumor: ·        Retinoblastoma

·        Rhabdomyosarcoma

·        Optic nerve glioma

·        Lymphoma

·        Hemangioma

·        Hemangioma

·        Schwannoma

·        Melanoma

·        Meningioma

·        Lymphoma

Other: ·        Dermoid cyst ·        Pseudotumor

·        Trauma

  • Mnemonic for childhood orbital masses: “LO VISON:”

o   Leukemia

o   Optic nerve glioma

o   Vascular malformation (hemangioma, lymphangioma)

o   Inflammation

o   Sarcoma, rhabdomyosarcoma

o   Ophthalmopathy, orbital pseudotumor

o   Neuroblastoma

  • Cystic orbital lesions:

·        Dermoid

·        Epidermoid

·        Teratoma

·        Aneurysmal bone cyst

·        Cholesterol granuloma

·        Colobomatous cyst

  • T1W hyperintense orbital masses:

Tumor: §  Melanotic melanoma

§  Retinoblastoma

§  Choroidal metastases

§  Hemangioma

Detachment: §  Coats disease

§  Persistent hyperplastic primary vitreous (PHPV)

§  Trauma

Other: §  Hemorrhage

§  Phthisis bulbi

§  Intra-vitreal oil treatment for detachment

  • Globe calcifications:

Tumor: ü Retinoblastoma à 95% are calcified, 35% are bilateral.

ü Astrocytic hamartoma àassociated with TS, NF.

ü Choroidal osteoma

Infection: (chorioretinitis) ü Toxoplasmosis

ü Herpes

ü CMV

ü Rubella

Other: Phthisis bulbi:

ü Calcification à in end-stage disease

ü Shrunken bulb

Optic nerve drusen:

ü Most common cause of calcifications in à adults

ü Bilateral

  • Sudden onset of proptosis:

·        Orbital varix à worsened by Valsalva maneuver.

·        Hemorrhage into cavernous hemangioma

·        CCF

·        Hemorrhage into lymphangioma

·        Thrombosis of superior orbital vein

  • Lacrimal gland enlargement:

Lymphoid lesions, 50%:  

o   Benign lymphoid hyperplasia

o   Mikulicz disease

o   Lymphoma

o   Pseudotumor

o   Sjögren syndrome

Epithelial neoplasm: o   Pleomorphic adenoma, 75%

o   Adenoid cystic carcinoma

 

  • Diffuse bone abnormality:

Signs:

·        bony enlargement (fibrous dysplasia), expansion, sclerosis

ü Fibrous dysplasia

ü Paget disease

ü Thalassemia

ü Congenital (rare):

o   osteopetrosis, craniometaphyseal and diaphyseal dysplasia

                                            

Sinuses

  • Radio-opaque sinus:

Normal variant: ü Hypoplasia

ü Unilateral thick bone

Sinusitis:
Acute à Air-Fluid Level (AFL)

Chronic à mucosal thickening, retention cysts

ü Allergic

ü Fungal à aspergillosis, mucormycosis

ü Granulomatous à sarcoid, Wegener disease

Solid masses: ü SCC

ü Polyp, inverted papilloma

ü Lymphoma

ü Juvenile angiofibroma:

o   Most common tumor in children.

ü Mucocele:

o   Expansile, associated with cystic fibrosis in children.

Post-surgical: ü Caldwell-Luc operation

 

Naso-oropharynx

  • Mucosal space mass:

Tumors: ·        SCC

·        Lymphoma

·        Rhabdomyosarcoma

·        Melanoma

Benign masses: ·        Adenoids

·        Juvenile angiofibroma

·        Thornwaldt cyst

  • Parapharyngeal & carotid space masses:

Tumors:

·   Salivary gland tumors:

       – 80% are à benign,

       – 20% are à malignant

·      Neurogenic tumor àschwannomas, glomus vagale)

·        Nasopharyngeal carcinoma

·        Lymphadenopathy à benign, malignant

Abscess, cellulitis  
  • Pre-vertebral mass:

ü Metastases

ü Chordoma

ü Osteomyelitis, abscess

ü Hematoma

 

Neck

  • Cystic Extra-thyroid / Thyroid lesions:

Cystic extra-thyroid lesions Cystic thyroid lesions
Neck:

ü Branchial cleft cyst: Lateral to carotid artery.

ü Thyroglossal duct cyst: Midline mass.

ü Ranula:  Retention cyst of sublingual glands.

ü Retention cysts of mucous glands (parotid)

ü Cystic hygroma (lymphangioma):   most common <2 years of age

ü uncommon lesions:

o   Teratoma.

o   Dermoid.

o   Cervical thymic cysts.

o   Hemangioma.

Naso-oropharynx:

ü Thornwaldt cyst

ü Mucus retention cyst (obstructed glands)

ü Necrotic SCC (thick wall)

Larynx, paralaryngeal space:

ü Laryngocele

ü Mucus retention cyst

ü Colloid cysts

ü Cystic degeneration

ü Cystic tumor:

     – Papillary cancer

     – Cystic metastases (papillary cancer)

 

  • Solid neck mass:

Tumors: ü SCC of the larynx or Naso-oropharynx  is common.

ü Lymphadenopathy:

  • Reactive hyperplasia
  • Malignant

ü Parotid tumors

ü Neural tumors:

  • Neurilemoma
  • Neurofibroma
  • Glomus tumors

ü Other rare tumors:

  • Mesenchymal, dermoid, teratoma
Inflammatory: ü Infection à abscess, fungal, TB

ü Granulomatous inflammation sarcoid, TB lymphadenitis = scrofula.

Congenital: ü Ectopic thyroid
  • Vascular head & neck masses:

Glomus tumor: ü Glomus vagale

ü Glomus jugulare

ü Carotid body tumor

ü Glomus tympanicum

Hemangioma:  
AVM:  
Aneurysm:

 

Often ICA:

ü Pseudo-aneurysm

ü Post-traumatic

 

IMAGING TECHNIQUES OF PHARYNX AND LARYNX

IMAGING TECHNIQUES OF PHARYNX AND LARYNX ARE VERY EASY, WE HERE WILL TRY TO SUMMERIZE THEM.

THANKS TO DR/ DAVID SUTTON MD, FRCP, FRCR, DMRD, FCan.AR (Hon) OUR BELOVED TEACHER

PLAIN XRAY:

  • Lateral Film is the best film projection, as Pharynx and Larynx clear of the cervical spine . as in Fig (1). The Film is placed against the shoulder and the incident beam is centered on :
  • Jaw Angle if we want Nasopharynx.
  • Thyroid Cartilage If we want Larynx.

 

Fig. 1 

(A) Some of the structures demonstrated on a plain lateral view of the neck. Xerography, although giving an excellent demonstration of the air-soft-tissue interface, is no longer available because of the high radiation dose used. 

(B) High-kV lateral neck gives an adequate demonstration of the soft tissue anatomy.

BARIUM SWALLOW

  • More benefit to opacify lesions below the crico-pharyngeus that cannot be assessed with a laryngeal mirror.
  • Tumours of the pharynx will be outlined by barium coating, especially those in the piriform fossae ( difficult to be seen with a mirror).
  • The normal larynx will appear as a `filling defect’ in the frontal projection with contrast in the piriform fossa on either side.
  • This is well shown on the oblique projection, obtained with the patient swallowing while the head is turned to one side.
  • When the larynx fails in its primary function as a protective sphincter for the lungs, ‘spill-over’ will occur to give a `barium laryngogram’.
  • This problem is seen more and more in an aging people, who dysphagia is due to mild stroke.

 

Fig . 2

Lateral View of normal Barium Swallow. The epiglottis (arrow) folds over the larynx as barium passes down into the esophagus .

Cine Radiology

  • It gives a good demonstration of degustation process.
  •  Passage of the bolus across the back of the tongue with an elevation of the larynx and tilting of the epiglottis down over the closed larynx is shown (Fig. 2).
  • Contrast then passes through the open cricopharyngeus into the esophagus.
  • Minor functional disorders of swallowing can only be shown by this technique (Fig. 3).
  • Videofluoroscopy is an alternative means of assessing swallowing function and a technique for assessment of oral or pharyngeal dysphagia.

Fig.3 

Cine barium swallow. Four frames in 1 s, frontal and lateral views. The patient had mild dysphagia due to unilateral vagal paralysis. Various
normal and abnormal features are demonstrated. 
Lateral view. 
1. The vallecula fills with barium and is then partially effaced by the normal backward compression of the tongue. 
2. The epiglottis is partially immobile and only tilts down to the transverse position, not fully covering the laryngeal inlet. 
3. Barium enters the vestibule of the larynx. This may occasionally be observed in asymptomatic subjects but is usually an indication of failure of the laryngeal sphincters ('spill-over'). 
4. At the same time the relation of the postphyaryngeal wall to the cervical spine does not change, indicating paralysis of the middle pharyngeal constrictor. 
5. Cricopharyngeus contracts and relaxes normally. 
AP view. 
6. The epiglottis shows little movement. 
7. The right side of the pharynx contracts normally but the left remains flaccid and filled with barium. 
8. Cricopharyngeus contracts and releases normally.

CT

  • CT is now the optimum method of imaging the outlines of the nasopharynx but also shows the soft-tissue structures of the infratemporal fossa and parapharyngeal space, which lie alongside the Naso- and oropharynx.
  • Formerly this region could be studied radiologically only in an indirect way by examination of surrounding bony structures or by invasive contrast examinations such as sialography and angiography.
  • The infratemporal fossa is situated below the skull base and is bounded by the pharyngeal musculature medially and the mandible laterally.
  • The most prominent and easily recognized structures within the infratemporal fossa are the pterygoid muscles.The anatomy of this region is depicted in Fig. 4.
  • Below, the infratemporal fossa is continuous with the parapharyngeal space.
    The role of CT for lesions in this region may be defined as:
    • To complement direct examination of lesions in the postnasal space
    .• To assess the size and situation and relations of a well-defined
    mass for prospective surgical removal, or the extent of local deep infiltration for radiotherapy planning.
    • To assess the relation of the mass to the great vessels and the parotid gland: by combining CT with contrast enhancement more accurate differentiation becomes possible.Contrast enhancement should be assessed in the vascular phase by intravenous infusion or bolus injection. Further sections in the coronal plane may give more information. Respiratory movement is less of a problem with the new fast scanners.
  • Scanning is begun at the level of the thyroid bone and sequential scans
    of 5 min slices are made in a caudal direction.
  • The shape of the airway alters as sequential scans are viewed. Above the rounded hypopharynx, it is bisected by the crescentic epiglottis.
  • Further down, the median and lateral glossoepiglottic folds delineate the valleculae.
  • Below this, the airway assumes a triangular shape and the piriform sinuses are seen as two lateral appendages separated by the aryepiglottic folds.
  • At the level of the cords the shape changes to the characteristic glottic chink or boat shape with the sharp anterior commissure extending right up to the thyroid cartilage in the midline (Fig. 5).
  • In the subglottic area, there is an even, symmetric oval shape which gives way at the level of the first tracheal ring to an oval flattened posteriorly, which may he likened to the shape of a horseshoe. 
  • CT provides a non-invasive, quick and effective radiological investigation of the larynx, and is not uncomfortable for the patient.
  • It can be done without risk in the face of respiratory obstruction, or after suspected laryngeal injury.
  • It gives an accurate assessment of laryngeal anatomy and involvement by tumor, particularly at the glottic level.
  • The value of such an assessment is greatly increased if partial laryngectomy is contemplated, but this is an unusual operation in the UK where carcinoma of the larynx is treated with radiotherapy and/or total laryngectomy.

 

Fig.4

Axial CT of soft tissues below the skull base. (A) Normal section through antra and postnasal space. The arrowheads indicate the openings of
the eustachian tubes. m = ramus of mandible; s = styloid process; p = pterygoid muscles. (B) Section at a slightly lower level passes through the soft palate
(sp). Tensor and levator palatini blend with the pharyngeal constrictors (c) to give a dense muscle mass. The enlarged but otherwise normal parotid gland
has a lower attenuation, i.e. appears darker, than the masseter muscle in front of it but not as dark as the fatty tissue in the parapharyngeal space. Thus the
medial limit of the deep parotid lobe can be defined (arrowhead). These features are best shown by MRI.

Fig.5
Axial CT Scan of the normal Larynx at the level of true vocal cords. 
Note the diamond shape of the airway with the cords in abduction.
Contrast is given , so CCA (A) and IJV (I) are shown.

MRI

  • MRI is superior over CT for neck masses.
  • MRI show neck vessels without the need to contrast.
  • T1WI gives the best spatial resolution.
  • T weighted Protocols give the best view of muscle invasion by carcinoma esp in Tongue base.
  • CT with contrast is superior over MRI in the evaluation of Neck Lymph Nodes, however, none of them can differentiate neoplastic from inflammatory hyperplasia, yet metabolic techniques like FDG-PET, SPECT is promising in that.
  • Sometimes the presence of Fat can obscure lesions, so fat saturation techniques are very useful, STIR protocol the most dependent one show increase signal intensity from most of the tumors especially Parotid Tumors. But It can’t be used with gadolinium contrast.
  •   Chemical Shift fat saturation techniques can show recurrent tumor after gadolinium injection.
  • Now Fat Saturation Techniques, used with T1 fast spin echo OR Post-gadolinium T protocols are more useful in defining Neck Lesions .   

 

Fig.6 (A) upper image: Sagittal MRI, T 1 -weighted, shows good differentiation between the tongue muscles, the genioglossi in the floor of the mouth and the surrounding fat, especially in the pre-epiglottic space (arrow).  (B) lowe image : Sagittal film in a child revealing subglottic stenosis (arrow)



Fig.7

Chordoma. Sagittal MR section, T,-weighted, shows a nonhomogeneous mass in the nasopharynx and replacing the basisphenoid.The tumor has burst out of its capsule and is displacing the brainstem posteriorly.

IMAGING OF CONGENITAL SKULL LESIONS

I-Lacunar Skull:

IMAGING OF CONGENITAL SKULL LESIONS IS A VERY RICH TOPIC TO TALK, LET’S GET A LOOK.

*Pathology:-

  • A dysplasia of the cartilage bones of the skull vault.
  • They lie in the thickest part of frontal, parietal & upper occipital bone.
  • Commonly associated with CNS anomalies: myelomeningiocele, hydrocephalus.

*Statistics:

In infants, disappear by 4-6 months.

*Radiology:-

1-Plain films:

Bilateral clusters of elliptical areas in which the vault is extremely thin are separated by thicker strands; some areas of the vault may be normal.

2-CT:

Shows that the scalloping predominantly affects the outer table.

II-Abnormalities of the Cranial Sutures:

A- Normal variation of the shape of the skull (Not pathological):

1-Dolichocephaly: longer skull in relation to width.

2-Brachycephaly: wider skull in relation to length.

3-Trigonocephaly: triangular skull due to the sharp anterior pointing of frontal bone due to premature fusion of metopic suture (in utero).

4-Bathrocephaly: square occipital bone overlapping the parietal bone at the lambdoid suture (should not be confused with traumatic lesions).

B-Premature fusion of Skull Sutures (Craniosynostosis):

Craniosynostosis

*Pathology:

  • Premature fusion of a calvarial suture.
  • Maybe primary or secondary to metabolic disease, bone dysplasia, hematological disorder or decreased intracranial pressure.

 *Statistics:

  • Most cases are detectable at birth.
  • M:F = 3:1.
  • Frequency of sutural involvement: sagittal 56%, multiple 14%, unilateral coronal. 11%, bilateral coronal 11%, metopic 17% and lambdoid 1%.

*Presentation:

Abnormally shaped head.

*Radiology:

1-Plain Film:

  • Analysis of skull shape is the best radiologic clue for diagnosis.
  • The resulting deformity depends on which suture is affected:

1-Sagittal Suture: 

Produces a long and narrow skull (dolichocephaly or scaphocephaly).

Severe craniosynostosis of the scaphocephalic type caused by premature synostosis of only a short segment of the sagittal suture of
a 2-week-old infant. A, In lateral projection, deformity resulting from the craniostenosis is clearly seen, but the sagittal suture itself is invisible (superior
black arrows). Coronal (black arrows) and lambdoid sutures (white arrow) are widened. B, In frontal projection, the sagittal suture is visible in its entirety
and is open except for a short segment (arrows) only a few millimeters long.
Caffey's Pediatric diagnostic imaging

2-Coronal suture:

May be unilateral or bilateral

-if bilateral produce a short and wide/tall skull (brachycephaly or turricephaly).

-if unilateral produce lopsided skull (plagiocephalic).

3-Metopic suture: 

produces a pointed forehead (trigonocephaly) and hypotelorism.

4-Lambdoid suture:

-if unilateral causes flattening of the occipital region (plagiocephaly)

-if bilateral, causes flattening of the entire occiput.

5-All sutures: produce sharp peaked crown (oxycephaly).

  • ‘Harlequin eye’ appearance is seen with complete coronal craniosynostosis which extends to the sphenoethmoidal synchondrosis
  • Cloverleaf skull (Kleeblattschadel) is caused by intrauterine premature closure of the coronal, lambdoid and sagittal sutures and is associated with lacunar skull (Luckenschadel) and brain dysgenesis or hydrocephalus.as figure below.

Rudlof - Atlas of newborn - volume III

NB: In microcephaly: small head due to premature closure of all the sutures+ primary mental defect.

2-CT:

  • Sutural narrowing, parasutural sclerosis, sharpening of suture edges and bony bridging across the sutures.
  • May only see buckling of suture with fibrous (non-bony) fusion.

3-US:

Delayed growth of biparietal diameter in early pregnancy

*Management:

  • Strip craniectomy in cases of single craniosynostosis is for cosmetic purposes as brain growth is not impaired
  • With universal craniosynostosis, strip craniectomy is mandatory to prevent complications of increased intracranial pressure and to allow brain growth.

NB: Prevent premature closure of sutures before 9 months:

                            – prevent mental defect.

                            –regain normal shape.

C-Widening of the sutures

  • occurs most commonly with raised intracranial pressure.
  • It is also seen with neoplastic infiltration of the sutures by, e.g., neuroblastoma, in which case the adjacent bone is often clearly eroded.

III-Abnormalities of skull base& foramen magnum:

 A-Platybasia:

*Definition:

A condition in which the base of skull appears relatively flattened

*Pathology:

  • There is an increase in the basal angle, as measured on a true lateral skull film.
  • The basal angle: lies between the two lines drawn from the anterior lip of the foramen magnum and the nasion to a point at or near the tuberculum sellae: the normal range is 120–140º; when the angle exceeds 148º the base of the skull is abnormally flat.
  • The term platybasia is sometimes used rather loosely to include basilar impression and basilar invagination.

B-Basilar Impression:

  • Indicates an elevation of floor of the posterior fossa.
  • Commonly associated with congenital anomalies of cervical spine.
  • The foramen magnum may be abnormal in shape and size.

C-Basilar Invagination:

Definition:

This is a term reserved for conditions in which the margins of the foramen magnum are inverted.

Etiology:

it is usually developmental, but similar changes may complicate rickets, Paget’s disease or other conditions in which the bone is softened.

Radiology:

The following lines may be used for assessment of basilar invagination on either plain films or CT scout topogram film:

1-Chamberlain’s line: drawn on the true lateral projection of the craniocervical junction, from the posterior end of the hard palate to the posterior border of the foramen magnum. Not more than 2 mm of the odontoid process should lie above this line

.2-MacGregor’s modification: as above, but using the occipital squama as the posterior landmark when the posterior lip of the foramen is not identified with ease. This line is vitiated if the head is tilted to one side. Not more than half the odontoid should be above this line.

3-The digastric line: on the occipitofrontal projection, between the two digastric notches. The atlanto-occipital joints should be below this line.=Basilar invagination is not the only condition in which the odontoid is unduly high: an abnormally short clivus and/or occipitalization of the atlas can give similar appearances.

NB: Both basilar invagination and platybasia are best assessed by mid-line sagittal MRI, when the effects on the neuraxis are also displayed.

III-Occipitalization of the Atlas:

*Definition:

The first cervical vertebra is fused to the skull base.

*Incidence:

1% of the population.

*Pathology:

  • In its mildest degree, the distance between the 2 posterior arch of the atlas and occipital bone is reduced and does not change with flexion and extension.
  • In ‘assimilation’ of the atlas, bony fusion is complete, and no separate components of the atlas can be identified.
  • The normal relationship of atlas and axis is, however, preserved, so that the odontoid is abnormally high.
  • The potential significance of this anomaly lies in its association with the Chiari malformation.

IV-Defective ossification:

in conditions such as:

1-Cleidocranial dysostosis.

2-Osteogenesis imperfecta.

 *Result in:

  • Very wide sutures, without other signs of raised intracranial pressure.
  • Wormian bones are prominent.
  • It is usually evident that the patient has a generalized bone disorder.

V-Hypertelorism:

  • A condition in which the orbits seem widely separated.
  • Usually associated with well developed ethmoid cells occupying the gap between the orbits.
  • Present in:

             1-Isolated congenital lesion (Grieg’s disease).

              2- Osteogenesis imperfecta.

              3- Cleidocranial dystosis.

              4- Fibrous dysplasia.

              5- Craniostenosis.

              6- Secondary to mucocele of ethmoid sinus (acquired).

 

**NOTES:-

*Apeurt’s syndrome = Syndactyly + oxycephally.        

*Acrocephally = Summit skull (brachycephally) (same as tower skull).

*Crourzon’s disease = (hereditary craniofacial dysostosis) is a form of acrocephally + facial bone hypoplasia, hypertelorism, exophthalmos, parrot-beak nose, prognathism, MR & corepulmonale .

*Carpenter’s syndrome = acrocephalopolysyndactyly