Brain Computed tomography.interpretation of brain ct

Ct modality for brain

1. BRAIN CT Presentation by Group 1 Mwaka Habanji Peter Kakwama Dorothy Maambo Deborah Ngwira

2. OUTLINE Introduction Principles of CT Types of CT Scans CT scan of head trauma -epidural haemorrhage -subdural haemorrhage CT scan of sinus pathology CT scan of masses -CT Scan in diagnosing brain tumours CT Scan of cerebrovascular accident (CVA)

3. INTRODUCTION Computed tomography (CT) This is a non invasive medical imaging test that uses x rays or the use of ionizing radiation to produce cross sectional images.

4. PRINCIPLE Collimated X rays are passed through the patient and information is obtained with a detector on the other side The X rays source and the detector are interconnected and rotated around the patient during scanning period. Digital computers then assemble the data that is obtained and integrate it to provide a cross sectional image(tomogram).

5. Types of CT Non contrast - CT no contrast agent is used Contrast enhanced CT – Contrast agent is injected to highlight specific areas Spiral(Helical) CT – There is continuous scanning in spiral motion. High speed CT- fast scanning for cardiac or pulmonary imaging. Low dose CT- reduced radiation dose 2 for screening or pediatric imaging.

6. CT Scan in head trauma Imaging modality of choice in head is non contrast CT scan Important CT finding of head trauma: Epidural haemorrhage(EDH) Subdural haemorrhage(SDH)

7. EPIDURAL HEAMORRIAGE Location of epidural is between the inner space of the skull and outer layer of the dura(periosteum) As a result of EDHs are usually limited in their extent by the cranial sutures. Features in ct : it is biconvex in shape,hyperdense sharply demarcated indications;evaluate the epidural hematoma or epidural abcesses and mass effect ( i.e midline shift and uncal herniations )may be present. Reporting outcomes location and size of the epidural lesions. Displacement of adjacent brain structures. midline shift or herniation. associated fractures or trauma .

8. SUBDURAL Location between the dura and the arachnoid mater. In contrast to EDH, Subdural haemorrhage (SDH) is not limited by sutures but are limited Dural reflections( falx cerebri, tentorium and falx cerebelli Appearance of SDH depends upon the time since its formation: a. Acute SDH (less than 3 days) crescentic hyperdense b. subacute SDH(3-14 days) nearly isodense for detection often CECT is needed. c. Chronic SDH(greater 14)hypodense with enhancing membrane. Indication : evaluate subdural hematomas SDH or subdural empymas . Reporting outcomes -location and size of subdural lesion -displacement of adjacent brain structures -midline shift or herniation -Associated trauma or bleeding disorders.

9. CT SCAN IN SINUS PATHOLOGY Physicians who are interested in treating patients with sinus disease must be able to read and interpret sinus CT scans. Indication: Evaluate the paranasal sinus disease, such as acute sinusitis, chronic sinusitis complication( e.g. abscess). Reporting outcomes: -opacification or air-fluid levels and sinuses. -thickening of the sinus mucosa. -bony changes( e.g erosion or destruction) complications( abscess, orbital cellulitis)

10. MASSES - Indication: Evaluate intra-axial or extra-axial brain masses (e.g., tumors, cysts, abscesses). - Reporting outcomes: - Location, size, and shape of the mass - Enhancement pattern (e.g., solid, cystic, ring-enhancing) - Edema or mass effect on adjacent brain structures - Associated bony changes (e.g., erosion or hyperostosis)

11. CT SCAN IN DIAGNOSING BRAIN TUMOR (MASSES) Although the most effective and common tool for diagnosing a brain tumour is the use of an mri scan , ct scan serve as an effective scanning tool for supratentorial abnormalities

12. STROKE Indication : Evaluate acute ischemic stroke, hemorrhagic stroke, or transient ischemic attack (TIA). - Reporting outcomes: - Early signs of ischemia (e.g., hyperdense artery sign, loss of gray-white matter differentiation) - Infarct location and size - Hemorrhage location and size - Vascular occlusion or stenosis

13. CT UN CEREBROVASCULAR ACCIDENT (CVA) HEMORRHAGIC STROKE) There are two types of haemorrhagic strokes : there are those that are caused by intracerebral haemorrhage (ICH) and those that are caused by subarachnoid haemorrhage(SAH). Common locations: basal ganglia and thalamus, pons and cerebellar hemisphere. Acute blood is markedly hyperdense compared to brain parechyma , and as such usually poses little difficulty in diagnosis.

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