subarachnoid haemorrhage,intraventricular haemomhagee 10min CT is the modality of choice Located between the dura and the inner table of the skull Tearing of the meningeal vessels especial middle meningeal artery The shape is usually biconvex ●May cross the mid line Associated with a skull fracture Subdural Haematoma Subdural hematoma is a collection of blood in the subdural space.The main 10min sources of bleeding are thom bridging veins.Rarely a subdural hematoma may be due to rupture of an aneurysm and subsequent laceration of the arachnoidal membraneSubdural hematomas are mainly frontoparietal in location and are usually crescentic in shapeSubdural blood may extend along the falx.in the midline.thus producing interhemispheric subdural hematomas. CT is the examination of choice 5min The density varies according to age of the hematoma:an acute hematoma is hyperdense.becomes isodense in the subacute phase hypodense when chronic(i.e.more than 12 weeks old Space-occupying effect subarachnoid haemorrhage 10min An acute extravasation of blood into the subarachnoid space CT scan clearly shows the hyperdensity of the subarachnoid spaces filled with blood Usually following rupture of an aneurysm of the circle of Willis Blood is cleared from the subarachnoid spaces within 1week Intramedullary spinal cord tumor Intramedullary spinal cord tumor is a tumor that arise from cells of thespinal cord 5minsubarachnoid haemorrhage , intraventricular haemorrhage e ⚫ CT is the modality of choice ⚫ Located between the dura and the inner table of the skull ⚫ Tearing of the meningeal vessels ,especial middle meningeal artery ⚫ The shape is usually biconvex ⚫ May cross the midline ⚫ Associated with a skull fracture Subdural Haematoma Subdural hematoma is a collection of blood in the subdural space，The main sources of bleeding are thorn bridging veins，Rarely a subdural hematoma may be due to rupture of an aneurysm and subsequent laceration of the arachnoidal membraneSubdural hematomas are mainly frontoparietal in location and are usually crescentic in shapeSubdural blood may extend along the falx, in the midline, thus producing interhemispheric subdural hematomas. ⚫ CT is the examination of choice ⚫ The density varies according to age of the hematoma: an acute hematoma is hyperdense, becomes isodense in the subacute phase hypodense when chronic (i.e. more than 12 weeks old ⚫ Space-occupying effect subarachnoid haemorrhage ⚫ An acute extravasation of blood into the subarachnoid space ⚫ CT scan clearly shows the hyperdensity of the subarachnoid spaces filled with blood ⚫ Usually following rupture of an aneurysm of the circle of Willis ⚫ Blood is cleared from the subarachnoid spaces within 1 week Intramedullary spinal cord tumor Intramedullary spinal cord tumor is a tumor that arise from cells of thespinal cord 10min 10min 5min 10min 5min