12/3/2023 0 Comments Spike definition mri![]() ![]() CT is the most accurate method for evaluating bone destruction of the inner and outer tables, the lytic or sclerotic nature of the lesion and for the evaluation of mineralised tumour matrix. Remodelling and expansion of skull tables.ĭermoid cyst (typically midline near anterior fontanelle)įatty signal on T1, variable signal on T2.Ĭalvarial lesions are radiologically evaluated with CT and MRI. Well-demarcated osteolytic lesion with sclerotic margins. Heterogeneous enhancement of the solid component. Solid component is isointense on T1 and iso/hypointense on T2. Mixed phase: yellow marrow maintained in all sequences.Ĭan have periosseous soft tissue component.Įxpansile, lytic lesion or solid lesion with areas of cystic changes. Lytic phase: hyperintense T2, hypointense T1 (with foci of interspersed T1 hyperintense yellow marrow). Mixed phase (lytic and sclerotic): skull vault enlargement “cotton-wool” appearance.īlastic phase: bone thickening and sclerosis. Lytic phase: “osteoporosis circumscripta”. Osseous venous vascular malformation (formerly haemangioma) Variable signal, extensive marrow oedema is typically present. Hypointense T1, variable signal on T2 depending on amount of cortical and trabecular bone. Variable signal depending on amount of mineralised stroma and fibrous tissue. Typically homogeneously sclerotic with “ground-glass appearance”. Skull lesions can be lytic or sclerotic, single or multiple with varied composition they may arise from osteogenic, chondrogenic, fibrogenic, vascular and/or other elements of bone (Tables (Tables2 2 and and3 3). On the other hand, malignant tumours have poorly defined margins, a wide transition zone, aggressive periosteal reaction and often have a soft tissue component these lesions cause dramatic bony destruction with intracranial or extracranial extension (Table (Table1) 1). In general, benign tumours have well-defined borders with a narrow transition zone sclerotic margins are frequently present. Recognition of benign and malignant imaging features is important for the radiological diagnosis. Diagram of the skull depicts patterns of bone destruction in the skull ( b) Underneath the calvarium are the meninges comprised of the dura mater, arachnoid mater and pia mater. The outer table is covered by periosteum. Covering the skull is the scalp which consists of the skin, subcutaneous dense connective tissue, galea aponeurotica and loose connective tissue. The skull is composed of the marrow space (diploe), inner and outer tables. Image depicting the calvarium anatomy ( a). The skull base forms the floor of the cranial cavity and, therefore, similar lesions can occur in this region however, there are lesions that are also specific to this location such as chordoma and chondrosarcoma. Lesions of the calvarium may originate from the bony structures or may be secondary to invasion of scalp-based lesions or brain-based lesions into the skull vault. It is composed of two cortical tables the inner and outer tables, and the diploe or marrow space between them (Fig. The skull vault is formed by the frontal, parietal, temporal and occipital bones and parts of the zygoma and sphenoid bone. Calvarial lesions may be benign or malignant fortunately, benign tumours are the most commonly encountered lesions. Clinical parameters such as the age and clinical history are important factors to guide the radiological diagnosis. ![]() Occasionally, they may present as a visible, palpable or symptomatic lump. Calvarial lesions are often asymptomatic and are usually discovered incidentally during computed tomography (CT) or magnetic resonance imaging (MRI) of the brain or as part of workup of local clinical symptoms or staging of other diseases. ![]()
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