Skull pathologies on Xrays

skull pathologies

1. SKULL PATHOLOGIES ON PLAIN RADIOGRAPHS Dr.Sachin Babanagar Assistant Professor , Dept of Radio-diagnosis, DY Patil Hospital , Kolhapur

2. Major Indications of Skull radiographs Dysplasias Diagnostic survey in abuse Abnormal Head shapes Infections and tumors affecting the skull bones Metabolic bone disease Leukemia Multiple Myeloma Trauma – medico-legal case, may detect some linear fractures Detection of calcifications, hyperostosis , lytic/sclerotic metastasis

3. Approach to Skull X-ray The various abnormalities that can be detected on plain skull X-ray can be categorized in the following groups : Abnormal density Abnormal contour of the skull Abnormal intracranial volume Intracranial calcification Increased thickness of the skull Single lucent defect Multiple lucent defects Sclerotic areas

4. ABNORMAL DENSITY Generalized reduced density Osteogenesis Imperfecta Hypophosphatasia Achondrogenesis Focal Reduced density Lacunar skull – focal areas of nonossified bone bound by normally ossified bone Generalized Increased density Osteopetrosis – basal bone initially, followed by calvaria Pyknodysostosis Localized increased density Fibrous dysplasia Osteoma Craniometaphyseal dysplasia

5. Osteogenesis Imperfecta Lacunar Skull O s t eop e t r osis Fibrous dysplasia

6. ABNORMAL CONTOUR NORMAL CONTOUR SUTURES INTR A CRANIAL CONTENTS NEW BONE F ORM A TION

7. PREMATURE FUSION OF SUTURES Craniosynostosis Commonest cause of abnormal contour in children Calvarium expands to accommodate the growing brain in the axis of the fused suture. Scaphocephaly Sagittal synostosis Most common of the isolated synostosis M:F = 4:1 Elongated narrow boat-shaped skull Turricephaly Closure of both coronal sutures and lambdoid sutures Short, wide skull with towering head, bulging temporal areas and shallow orbits The recessed supraorbital rims and hypoplasia of basal frontal bones gives cloverleaf skull appearance.

8. Plagiocephaly Unilateral coronal or lambdoid synostosis Unicoronal synostosis is the second most common form of craniosynostosis after sagittal synostosis. 2/3 rd cases occur in females and 10% are familial There occurs elongation of the orbit, elevation of the lateral portion of the ipsilateral orbital rim – the Harlequin eye appearance Tilting of the nasal septum and crista galli towards the ipsilateral side. Expansion of bony calvarium due to presence of slow growing intracerebral or sub arachnoid SOLs Arachnoid cysts Chronic SDH – calcifications may facilitated the diagnosis Abnormal bone formation Achondroplasia – defective enchondral ossification Skull base is affected (develops from cartilage). Calvarium not affected ( membranous bones) Small foramen magnum, enlarged cranium, frontal bossing and large jaws.

9. Sagittal synostosis Turricephaly(oxycephaly) Plagiocephaly Harlequin eye – coronal synostosis

10. Cloverleaf skull ACHONDROPLASIA

11. ABNORMAL INTRACRANIAL VOLUME Abnormal cranial volume can be determined by measuring the skull directly and then comparing the measurements to the standard for age and body size. Skull vault to face ratio. Volume of skull vault to face is 4:1 at birth, 3:1 by 2 years, 1.5:1 by adulthood. Enalrged head size Hydrocephalus Macrocephaly Hydranencephaly Pitutary dwarfism Small Skull Microcephaly – otherwise normal contour, associated with mental retardation. Sinuses are large and digital or convolutional markings are absent or decreased Sutures fuse early, but this is not the cause but a result of microcephaly D/D from premature fusion of sutures

12. Increased thickness of the skull Early cessation of brain growth Cerebral atrophy Hemolytic anemia – thalassemia, sickle cell, hereditary spherocytosis Progressive hydrocephalus Hemolytic anemias – most striking in thalassemia. Diploic space is widened with striking radial striations ( “hair – on –end”). PNS may be completely obliterated. Progressive hydrocephalus Without shunting – large bony calvarium decreased diploic space With shunting – abnormal expansion ceases, arrested hydrocephalus, sutures close, inner table thickens, diploic space widens

13. HAIR – ON END APPEARNCE

14. Single radiolucent Defect Considerations while dealing with a single lucent lesion : Location Associated soft tissue swelling Table of the bone involved Margins – sharp, ill-defines, sclerotic Causes of radiolucent defects : Congenital – parietal foramina, anomalous apertures, meningoencephalocele, dermal sinus Acquired – trauma, infections, tumors and histiocytosis.

15. Parietal Foramina Rounded lytic defects Bilaterally symmetrical Located in posterior parietal bone Meningoencephalocele Midline Frontal or occipital Sharp margins Associated soft tissue swelling Dermal Sinus Midline radiolucent defect Sharp, slightly sclerotic margin Associated lipoma or nevus of the overlying soft tissues Intracranial components – CT Fractures At the site of injury associated with soft tissue swelling

16. Linear nondepressed fractures – Radiolucent lines. Not to be confused with vascular grooves ( ill-defined, undulant course) and sutures ( saw-toothed, expected anatomical location) Depressed fractures – Area of increased radiodensity surrounded by a radiolucent zone. In children, arachnoid membrane may herniate through the torn dura and pulsations lead to enlargement of the arachnoid collection resulting in Growing fracture. Bulging membranes lead to the formation of a Leptomeningeal cyst. Infections Rare Follow trauma or a spread from other sites Radiographically – mottled irregular lucencies which have well-defined borders and associated swelling of the scalp. Epidermoid tumors Congenital inclusion of epithelial cells within the calvarium Well-defined lytic lesions with sclerotic borders Not necessarily mid-line Intracranial epidermoids may produce a radiolucent shadow mimicking a lytic lesion.

17. Malignant lesions Primary osteosarcoma – gross destruction of the bone with well defined margins and soft-tissue component Metastasis Intacranial mass lesions may present as lytic skull lesion Neurofibromatosis is a rare cause of lytic skull lesion – not due to neurofibroma, but due to mesenchymal defect. Histiocytosis X ( Eosinophilic granuloma, Letterer-Siwe disease, Hand-Schüller-Christian disease) A single lytic lesion having sharp, non-sclerotic barder and bevelled edges is characteristic of eosinophilic granuloma. A small bone in the center – Button sequestrum. Other two variants have larger, multiple and punched out lesions

18. Paritel Foramina DERMOID ENCEPHALOCELE

19. E P IDE R M O ID HEMANGIOMA OSTEOMYELITIS

20. E OSINO PH ILIC GRANULOMA

21. LINEAR SKULL FRACTURE GROWING FRACTURE DEPRESSED FRACTURE

22. Multiple Radiolucent Defects Children Craniolacunia Wormian Bones Increased Convolutional Markings Histiocytosis Metastasis – neuroblastoma, leukemia, Ewing’s Sarcoma Adults Multiple Myeloma Metastasis Hyperparathyroidism

23. CRANIOLACUNIA NEUROBLASTOMA – SUTURAL METASTASIS NEUROBLASTOMA - METS

24. HAND-SCHULLER-CHRISTIAN METASTASIS MULTIPLE MYELOMA HYPERPARATHYROIDISM

25. Wormian Bones Convolutional Markings – Copper Beaten Skull

26. Sclerotic Areas of Skull Osteopetrosis Fibrous Dysplasia – Sclerotic lesion with loss of trabecular pattern/ mixed lesions Paget’s Disease – “Cotton wool” skull, thickening of diploic space, enlargement, osteoporosis circumscripta Osteoma Proteus Syndrome – hyperostosis Meningioma – hyperostosis Hyperostosis frontalis interna – elderly, inner table, does not cross midline, spares diploic space

27. OSTEOPETROSIS FIBROUS DYSPLASIA O S T E O M A HYPEROSTOSIS

28. OSTEOPOROSIS CIRCUMSCRIPTA PAGET’S DISEASE

29. MENINGIOMA – HYPEROSTOSIS WITH PROMINENT VASCULAR MARKINGS HYPEROSTOSIS FRONTALIS INTERNA

30. INTRACRANIAL CALCIFICATION Physiological – Pineal, Choroid plexus, Habenular, basal ganglia, falcine, anterior petroclinoid ligaments, pitutary (rare), ICA. Abnormal – Familial – Tuberous Sclerosis, Sturge-Weber Syndrome, Idiopathic familical cerebrovascular calcinosis (Fahr’s) Metabolic – Hypoparathyroidism, Pseudohypoparathyroidism, Hyperparathyroidism Inflammatory – CMV, Toxoplasmosis, Rubella, Abscess Vascular – AVM, Aneurysm, Hematoma Neoplasm – Craniopharyngioma, Astrocytoma, oligodendroglioma, pinealoma

31. PINEAL CALCIFICATION TUBEROUS SCLEROSIS STURGE-WEBER SYNDROME Vein of Galen Aneurysm

32. SUPRA SELLAR CALCIFICATION - CRANIOPHARYNGIOMA INTRACRANIAL CALCIFICATION - TORCHES

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