Ct scan agp
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This document discusses the radiological anatomy of the brain as seen on CT scans. It begins by outlining the systematic approach used to interpret CT scans, including assessing symmetry, midline structures, cross-sectional anatomy, and skull and soft tissues. It then describes key anatomical structures visible on CT such as the cranial fossae, meninges, fissures, ventricles, grey and white matter. The document also discusses how CT is used to identify ischemic strokes at different stages, from immediate changes like hyperdense vessels, to acute swelling, subacute resolving swelling, and chronic infarction. It notes CT perfusion can identify the infarct core and penumbra using parameters like CBV, CBF, MTT and
Ct scan agp
- 1. RADIOLOGICALANATOMY OF BRAIN IN CT SCAN Akshai George Paul
- 2. Systemic Approach to head CT Symmetry Midline Cross-sectional anatomy o Brain tissue o CSF space o Skull and soft tissues Subdural space Bone windows
- 4. Meninges
- 6. Fissures
- 7. Ventricles
- 12. Normal CT of Brain • Sulci are symmetrical on both sides • Midline is straight • Grey-white distinction is clear • Ventricles are normal sized • Skull is intact with no scalp edema.
- 13. Above the level of Foramen Magnum
- 14. At the level of FourthVentricle
- 15. Above the level of fourth ventricle
- 16. At the level of theThirdVentricle
- 19. Above the ventricular level
- 27. CT IN ISCHEMIC STROKE
- 28. Ischemic stroke can be further classified on the basis of the time from the onset of symptoms as ■ hyperacute ■ acute ■ subacute ■ chronic
- 29. the goals of CT in an acute setting are: 1. exclude ICH 2. look for early features of ischemia 3. exclude other IC pathologies that may mimic the stroke
- 30. Immediate change • The earliest CT sign visible is the hyperdense segment of a vessel, representing the intravascular thrombus or emboli. • Its most often observed in the MCA: MCA Dot sign/ hyperdense MCA sign
- 31. Acute stroke • Loss of grey-white matter differentiation . • Cortical hypodensity with associated parenchymal swelling with resultant gyral effacement • Insular ribbon sign • There will be significant mass effects also due to the swelling
- 32. Subacute stroke • The swelling starts to subside and small amounts of cortical petechial hemorrhages may appear. • This is known as CT fogging phenomenon. • Can be misleading as the affected cortex may appear normal.
- 33. Chronic infarct • Here the residual swelling passes and gliosis sets in. • Finally it appears as a region of low density with negative mass effect. • Sometimes, cortical mineralisation can be seen as hyperdense areas.
- 34. CT perfusion ■ Allows to identify both the core of infarct and the penumbra. ■ The following parameters are used for its identification: Cerebral blood volume(CBV) Cerebral blood flow(CBF) Mean transit time(MTT) Time to peak (TTP)