WordPress.com



2457459502140Bone00Bone15519409502140Skull fractures (especially basal skull fracture); sinuses and air cells00Skull fractures (especially basal skull fracture); sinuses and air cells15494009151620Symmetrical with no dilation, effacement, shift, blood00Symmetrical with no dilation, effacement, shift, blood2432059151620Ventricles00Ventricles2438405498465Brain00Brain15506705497195Look for: tumour, atrophy, abscess, mass effect, CVA, intracranial air, grey-white differentiation, symmetry, hyper/hypodensities; compare gyri for evidence of effacement; trace falx for evidence of midline shiftHyperdense: blood, IV contrast, calcificationHypodense: air, fat, ischaemia, tumour; active bleeding / old bloodInfarct: no abnormality in 1st few hours (sensitivity 50% at 6hrs, specificity >95%) Early changes suggest large infarct: loss of grey-white differentiation is 1st sign, parenchymal hypodensity, effacement of sulci, ventricular compression, local mass effect, loss of insular ribbon, obscuration of lentiform nucleus, hyperdense MCA or other (100% specificity, 30% sensitivity for MCA) hypoattenuation at 24 hours (max at 3-5/7) increased attentuation (for few weeks) decreased attenuation with mass effect and ill defined margins isodense at 1-2/52 more decreased attenuation looks like CSF at few months Poor outcome with thrombolysis if: hypodensity >1/3 MCA territory (19% fatal haemorrhage vs 0%; 7% good 3/12 outcome vs 17%), sulcal effacement, mass effect, cerebral oedemaICH: increased attenuation in 1st week (hypodense area may be active bleeding) decreased density and blurring of margins from periphery after 1/52 surrounding oedema (may contrast enhance mimicking cancer) loss of mass effect isodense at 3/52 hypoattentuation at 10/52 little residual change00Look for: tumour, atrophy, abscess, mass effect, CVA, intracranial air, grey-white differentiation, symmetry, hyper/hypodensities; compare gyri for evidence of effacement; trace falx for evidence of midline shiftHyperdense: blood, IV contrast, calcificationHypodense: air, fat, ischaemia, tumour; active bleeding / old bloodInfarct: no abnormality in 1st few hours (sensitivity 50% at 6hrs, specificity >95%) Early changes suggest large infarct: loss of grey-white differentiation is 1st sign, parenchymal hypodensity, effacement of sulci, ventricular compression, local mass effect, loss of insular ribbon, obscuration of lentiform nucleus, hyperdense MCA or other (100% specificity, 30% sensitivity for MCA) hypoattenuation at 24 hours (max at 3-5/7) increased attentuation (for few weeks) decreased attenuation with mass effect and ill defined margins isodense at 1-2/52 more decreased attenuation looks like CSF at few months Poor outcome with thrombolysis if: hypodensity >1/3 MCA territory (19% fatal haemorrhage vs 0%; 7% good 3/12 outcome vs 17%), sulcal effacement, mass effect, cerebral oedemaICH: increased attenuation in 1st week (hypodense area may be active bleeding) decreased density and blurring of margins from periphery after 1/52 surrounding oedema (may contrast enhance mimicking cancer) loss of mass effect isodense at 3/52 hypoattentuation at 10/52 little residual change2438401340485Blood00Blood56248304558665Subarachnoid haemorrhage – blood in cisterns or cortical sulci00Subarachnoid haemorrhage – blood in cisterns or cortical sulci579437531413450034207454536440Subdural haematoma – concave; crosses sutures but not midline; usually venous injury / bridging vessels00Subdural haematoma – concave; crosses sutures but not midline; usually venous injury / bridging vessels371919531413450015513054537075Epidural haematoma – biconvex; doesn’t cross sutures; usually arterial injury00Epidural haematoma – biconvex; doesn’t cross sutures; usually arterial injury179641531413450054451252546985Chronic – Hypodense at 4-6/5200Chronic – Hypodense at 4-6/5233077152546985More hyperdense for 1st few hours / days becomes isodense (subacute) at 1-4/5200More hyperdense for 1st few hours / days becomes isodense (subacute) at 1-4/5215513052546985Acute - Initially white (active bleeding is dark)00Acute - Initially white (active bleeding is dark)558673012579350016637001263650005027930177101500321246517456150038303201263650001551305965200Patient information; orientation; contrast vs non-contrast00Patient information; orientation; contrast vs non-contrast245110965200Opening00Opening246380330200How to Read a CT Head00How to Read a CT Head25876256478905002066290873696500500316571596252963545715962500294640715962550031654869815285813548698150029464048698154997450337693015652753376295Most important: circummesencephalic (ring around midbrain) suprasellar (star shape at Circle of Willis) quadrigeminal (W shape – happy smile) sylvian (between temporal and frontal lobes)Look to see: if there’s blood, if the cisterns are open00Most important: circummesencephalic (ring around midbrain) suprasellar (star shape at Circle of Willis) quadrigeminal (W shape – happy smile) sylvian (between temporal and frontal lobes)Look to see: if there’s blood, if the cisterns are open2946403376930Cisterns00Cisterns294640391160Causes of Ring Enhancing Lesions MRTHAMPA00Causes of Ring Enhancing Lesions MRTHAMPA15652752844165A00A19119852843530Abscess (toxoplasma, TV, Cryptococcus, candida, staph aureus, streptococcus, prevotella, pseudomonas, anaerobes, bacteroides)00Abscess (toxoplasma, TV, Cryptococcus, candida, staph aureus, streptococcus, prevotella, pseudomonas, anaerobes, bacteroides)15646402496185P00P19119852497455Primary brain tumour (gliobastoma, CNS lymphoma, cystic astrocytoma); post-op changes00Primary brain tumour (gliobastoma, CNS lymphoma, cystic astrocytoma); post-op changes1231901644650019119852146935Multiple sclerosis00Multiple sclerosis15652752146935M00M19119851800225Aneurysm00Aneurysm15646401798955A00A15652751442720H00H19119851442720Haematoma (resolving)00Haematoma (resolving)19119851091565Tuberculoma00Tuberculoma15652751091565T00T1564640743585R00R1911985744855Radiation necrosis00Radiation necrosis1911985387351Metastases00Metastases1565275387350M00M34823407799070447929070916800035579054988560289687058248550012204704178300003968754815840227901529222705019675121158030702251211580003968751211580262890050800000 ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download