頭部電腦斷層讀片口訣 - 見血可是非常糟！
Blood
- Locations of the major blood supply to the brain, Circle of Willis in the suprasellar cistern
- Acute blood is bright white on CT
- EDH (lens-shaped), SDH (sickle-shaped), Intraparenchymal (esp. basal ganglia, deep bleed vs. cortical bleed), intraventricular (watch for hydrocephalus), SAH (Blood in cisterns)
- Acute sequelae: EDH - lateral or transtentorial herniation.
Can: 4 key Cisterns
- Quadrigeminal (W-shaped), circummesencephalic (ring around midbrain), suprasellar (star-shaped, circle of Willis), sylvian (between temporal and frontal lobes)
- Blood in cisterns (SAH, aneurysmal rupture), effacement of cisterns (IICP)
Be: Brain parenchyma (adjust contrast window)
- Symmetry, shift, gray-white differentiation, hyper/hypodensity, sucal patterns, basal ganglia location, pneumocephalus.
- Limitations of posterior-fossa imaging.
- Early ischemic stroke: loss of gray-white differentiation, asymmetry of gyral pattern, insular ribbon sign
- Trauma -contusion; Nontrauma- tumor, abscess, or atrophy
- Contrast effect on BBB destruction.
Very: Ventricles
- CSF produced in lateral ventricles (back-to-back commas) → Third ventricle (slit-shaped) → aqueduct of Sylvius → Fourth ventricle (Helmet-haped). Approximatedly 20ml/h
- Look for effacement (hydrocephalus), ventricular shift, and blood.
- Acute hydrocephalus: transependymal flow
- Brain Atrophy
Bad: Bony skull (use bone window)
- Note soft tissue swelling, basilar skull fracture, and sinus pathology.
- Look for blood/air-fluids level in sinuses/mastoid air cells, and widened sutures.
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