بسم الله الرحمن الرحيم

1. بسم الله الرحمن الرحيم

2. BRAIN CT IN EMERGENCY

3. Lecture Objectives: • Normal anatomy of brain CT • Trumatic brain injury • Subarachnoid hemorrhage • Intraparenchymal hemorrhage • Stroke • Brain edema • Cerebral herniation

6. A. Orbit B. Sphenoid Sinus C. Temporal Lobe D.ExternaAuditory Canal E. Mastoid Air Cells F. Cerebellar Hemisphere

7. A. Anterior Horn of the Lateral Ventricle B. Caudate Nucleus C. Anterior Limb of the Internal Capsule D. Putamen and Globus Pallidus E. Posterior Limb of the Internal Capsule F. Third Ventricle G. Quadrigeminal Plate Cistern H. Cerebellar Vermis I. Occipital Lobe

8. A. Falx Cerebri B. Frontal Lobe C. Body of the Lateral Ventricle D. Splenium of the Corpus Callosum E. Parietal Lobe F. Occipital Lobe G. Superior Sagittal Sinus

9. A. Falx Cerebri B. Sulcus C. Gyrus D. Superior Sagittal Sinus

10. CT SCAN.. Bone window fracture

11. CT SCAN.. Contrast enhanced CT: IV injection of contrast medium is often given because the abnormality not seen in pre contrast scans may be rendered visible following contrast enhancement (consequence of breakdown of blood brain barrier allowing contrast to enter the lesion particularly in neoplasm, infection, inflammation and certain stage of ischemia). Also it is helpful in demonstrating blood vessels MCA ACA Basilar artery Straight sinus Superior sagittal sinus Contrast enhanced CT

12. CT SCAN.. Computer reconstructions can in selected circumstances be made from the axial sections which then provide images in coronal or sagittal planes. Sagittal reconstruction Coronal reconstruction

13. CT SCAN.. CTA CT angiography is helpful in diagnosis of vascular diseases and abnormalities such as stenosis, occlusion or vascular malformation Occlusion of left middle cerebral artery

14. Computed Tomographic Cerebral Venography (CTV) CTV Can be reliably assess intracranial venous system Comparable to MR angiographic techniques Rapid and readily available Avoids many patient contraindications that may prevent MR evaluation Using iodinated contrast material, requires complex post processing to remove bony structures from reconstructed images

15. CT SCAN.. CT PERFUSION cerebral blood volume cerebral blood flow

16. CT SCAN.. CT PERFUSION In acute stroke, very early cranial CT may be normal. Perfusion CT shows great promise in refining the selection of patients suitable for thrombolysis, as it can accurately determine infarct core from potentially salvageable ischaemic penumbra. Some cerebral tumours are associated with angiogenesis and a breakdown of the blood-brain barrier. Angiogenesis can be detected as an increase in flow and volume parameters, and blood-brain barrier breakdown can be quantified as contrast accumulates in the interstitial space. Such aggressive features can distinguish malignant from benign tumours when standard imaging may not.

18. Primary: Extraaxial hemorrhage: - Epidural hematoma - Subdural hematoma - Subarachnoid hemorrhage Intraaxial lesions: - Diffuse axonal injury - Cortical contusion - Deep gray matter injury - Brainstem injury - IVH Secondary: - Brain herniation - Traumatic ischemia - Diffuse cerebral edema - Hypoxic brain injury Traumatic brain injury:

19. Epidural hematoma • 90% is arterial (middle meningeal artery) • Temporoparietal • Biconvex, lenticular • Does not cross suture lines, crosses dural reflections • Commonly associated with skull fractures

21. Bone window Brain window Acute extradural hemorrhage CT SCAN.. fracture The window settings are selected for the brain, but may be altered to shows the bones.

22. Subdural hematoma • Tear of cortical bridging veins • Cresentric along the brain surface • Crosses suture lines, does not cross dural reflections • Common in infants (child abuse) and in the elderly

27. Subarachnoid hemorrhage • Hyperdense CSF in the basal cisterns, sylvian fissure and subarachnoid space • Aneurysm rupture is the most common cause in non trauma patient • Patients present with the worst headache of their life

28. Subarachnoid hemorrhage

29. Subarachnoid hemorrhage • The pattern of hemorrhage may give a clue to the location of the ruptured aneurysm: • A-com aneurysm⇒interhemispheric fissure • P-com aneurysm⇒ipsilateral basal cisterns • MCA trifurcation⇒sylvian fissure • Basilar tip⇒interpeduncular cistern, intraventricular • PICA ⇒posterior fossa cisterns, intraventricular

30. Pseudo-subarachnoid hemorrhage • Symmetric increased density in the basal cisterns with no sulcal density • 30-40 HU • Assoaciated with generalized brain edema • History of recent cardiopulmonary resuscitation

32. Diffuse axonal injury • Axonal disruption from shearing forces of acceleration/deceleration • Patients are unconscious with severe head injury • Common locations: - Lobar gray/white matter junction - Corpus callosum - Dorsolateral brain stem

33. Diffuse axonal injury • Initial CT is often normal. Petechial hemorrhage develops later. • Susceptibility-sensitive, gradient-echo MR sequences are most sensitive for detecting hemorrhagic shear injuries.

34. Diffuse axonal injury

36. Cortical contusions • Focal hemorrhage/edema secondary to brain impacting on bone or dura • Located 180 degrees from the site of direct impact (contrecoup) • Characteristic locations: - Anterior temporal - Inferior frontal - Parasagittal hemisphere - Splenium of the corpus callosum - Brainstem

39. Intra ventricular hemorrhage

40. Intraparenchymal hemorrhage • Causes: - Hypertension - Amyloid angiopathy - Vascular malformations - Coagulopathy - Trauma - Drug induced - Tumor hemorrhage

43. Stroke • Types: - Ischemic stroke - Hemorrhagic stroke - Venous occlusion

44. Ischemic stroke • Nonenhanced CT is the initial investigation of choice • Exclude hemorrhage and underlying mass or AVM Imaging findings: • Normal in early stroke • Hyperdense clot in the affected artery • Insular ribbon sign • Sulcal effacement • Cytotoxic edema develops by 6 hours

45. Ischemic stroke • Acute infarction cannot be excluded on the basis of a negative CT. • Diffusion weighted MRI is most sensitive for detecting acute infarction • Hemorrhagic transformation can develop in the subacute stage (gradient echo MRI)

48. Insular Ribbon Sign

49. 1st Day

50. 2nd Day