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Slide 2 Head CT Basics : Trauma Micelle Haydel, MD LSU-New Orleans Slide 3 First, a little test Slide 4 1. Slide 5 2. Slide 6 3. Slide 7 4. Slide 8 5. Slide 9 6. Slide 10 7. Slide 11 8. Slide 12 9. Slide 13 Head CT Interpretation the basics Slide 14 A Little History... In the early 1970s, Hounsfield developed a way of computerizing Xrays to select certain densities for viewing. Plain films: black, white or a few shades of grey CT: thousands of shades of grey based on the density of the tissue (Hounsfield Units) Slide 15 What We Need to Know Air is very black (less than -300 HU) Water/CSF is black (near 0 HU) Bone is very dense/white (500-3000 HU) Blood is white (60-80 HU) Brain is gray 35-50 HU Slide 16 Quad 3rd Before we look at abnormal, A little normal geography: Use the Cisterns& Ventricles as landmarks 4th Supra Slide 17 4th Ventricle Slide 18 Suprasellar Cistern Slide 19 Sella turcica Suprasellar Slide 20 3 rd Ventricle Quadrigeminal Cistern Slide 21 Temporal Horn of Lateral Ventricle Slide 22 3 rd Ventricle & Quadrigeminal Cistern Slide 23 Lateral Ventricles Frontal Occipital Slide 24 Lateral Ventricles Slide 25 4th Quad 3rd Suprasellar Review: Temp Horn Slide 26 Normal Head Slide 27 Slide 28 Slide 29 Slide 30 Slide 31 Slide 32 Slide 33 Slide 34 Slide 35 Slide 36 Slide 37 Slide 38 ABNORMAL CTs Slide 39 On each brain slice look for: Symmetry, symmetry, symmetry sulci cisterns and ventricles grey-white differentiation Slide 40 Identify What Doesnt Belong Hyperdensities (whiter) extra-axial hematomas (SDH, EDH) ICB or contusion SAH in sulci, cisterns or ventricles Hypodensities (darker) pneumocephaly (air is darker than CSF) infarction Slide 41 Identify What Doesnt Belong Localized or diffuse edema effacement of sulci or cisterns distortion of gray-white matter interface enlarged ventricles, temporal horn Fractures soft tissue swelling fluid (blood) in sinuses or mastoid air cells in children, look for widened sutures Always look at bone windows Slide 42 Blood: Acute blood is white (60-80 HU) on CT, due to the density of hemoglobin. As hgb breaks down, the HU decrease (i.e. subacute and isodense hematomas) Slide 43 Dura mater Arachnoid Pia mater Dura tightly adhered to skull, but loosely to brain. Slide 44 Epidural Hematoma -Lens shaped (dura tightly adhered to skull -Can cross midline -Frequently assoc. with fracture Slide 45 Small Epidural Hematoma Slide 46 Very Small Epidural Hematoma Slide 47 Epidural with fracture Slide 48 Very Small Epidural Hematoma with fracture Slide 49 Epidural with Pneumocephaly Slide 50 Subdural Hematoma Follows the contour of the brain & doesnt cross the midline Slide 51 Small SDH tracking down midline Slide 52 Small Subdural Hematoma Slide 53 Very Small Subdural Hematoma Slide 54 Large Subdural Hematoma with shift Slide 55 Isodense Subdural Hematoma Slide 56 Hygroma with shift s/p SDH Slide 57 Acute on Chronic Subdural Hematoma Slide 58 Intraparenchymal Bleed Slide 59 Intraparenchymal Bleed & Skull Fracture Slide 60 Intraparenchymal Bleed & Contusions Slide 61 Contusion Slide 62 Pneumocephaly and contusion Slide 63 Subarachnoid hemorrhage- Blood in the 4 th Ventricle Slide 64 Subarachnoid blood in the suprasellar cistern Slide 65 Subarachnoid blood tracking along the sulci Slide 66 Intra-Ventricular Blood throughout Slide 67 Subdural hematoma Temporal Horn enlargement Slide 68 Epidural Enlarged Temporal Horn Slide 69 Diffuse Edema, SAH tracking across tentorium Slide 70 Subfalcean herniation (midline shift) due to SDH Slide 71 Uncal herniation (EDH & subfalcean herniation) Slide 72 Diffuse Edema s/p SAH Slide 73 Soft-tissue swelling Fracture Slide 74 .the results Slide 75 1. Epidural Hematoma Slide 76 2. Skull Fracture SAH Slide 77 3. Cerebral Contusion Slide 78 4. SAH Slide 79 5. Subdural Hematoma Subfalcean Herniation Slide 80 6. Epidural Hematoma Slide 81 7. Diffuse Edema Slide 82 8. Isodense Subdural Slide 83 9. Subdural Hematoma Slide 84 ?