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Matthias KerlInstitute for Diagnostic and Interventional Radiology Johann Wolfgang Goethe University Frankfurt am Main Diagnosing Vascular Cranial Diseases Using Compted Tomography
CTA of the Carotids: Background • Standard of reference • DSA • Poor correlation to • postmortem findings1 • Vascular ultrasound • Poor in assessment of • filiform stenoses • Calcifications cancel the • depiction of the vessel • lumen • Symptomatic patients1: • High benefit of CEA for • patients with >70% stenosis • Moderate benefit of CEA for • patients with 50-70% stenosis • Asymptomatic patients2: • Small benefit in terms of absolute risk • Standard of reference • DSA • Poor correlation to • postmortem findings1 • Vascular ultrasound1 • Poor in assessment of • filiform stenoses • Calcifications cancel the • depiction of the vessel • lumen • Unable to display vascular wall / surrounding soft tissue • In complex stenoses >1 angiographic projections needed • But: • Excellent display of vessel lumen regardless of blood flow • Excellent reproducibility • Excellent portray of arterial anatomy (Aortic arch to cerebral vessels) 1Rothwell PM, Lancet (2003) 361:107–116 2Moore WS, Circulation (1995) 91:556–579 1Schulte-Altedorneburg G, J Neurol (2005) 252 : 575–582 1Polak JF, Radiology (1998) 209:288–289
CTA of the Carotids: Background • Alternative non-invasive • procedures: • CTA • Alternative non-invasive • procedures: • CTA • Alternative non-invasive • procedures: • CTA • Filling techniques • - First-pass technique • - Passage of a bolus of CM through imaged volume • - Depict lumen & surrounding arterial wall / soft tissues • „Flow-dependent“ techniques • US (Doppler, duplex / color-flow) • MRA (TOF / PCA) • Measure blood must through volume of interest MRA CTA (1) x-ray tubes with adequate photon flux & cooling capacity (2) detector technology allowing simultaneous gathering of multiple thin axial profile data sets (3) continuous rotating x-ray tubes with continuous table travel (helical or spiral technology
CTA of the Carotids: MDCT Spiral-CT 4-row MDCT 64-row MDCT • Alternative non-invasive • procedures: • CTA Isotropic Voxel
CTA and MRA of the Carotids: MDCT • Alternative non-invasive • procedures: • CTA
CTA of the Carotids: MDCT • Alternative non-invasive • procedures: • CTA
CTA of the Carotids: Minimal requirements • >4-slice Multidetector-row CT • Scanning • >4 x 2.5 mm collimation • >0.5 sec rotation time • 100mAs / 120kV • CM: 120ml @ 3ml/s • 300mgI/ml • bolus triggering / test bolus • Image Reconstruction • slice tickness / increment • 3/3mm • 3/1.5mm (MPR) • medium soft tissue kernel B30f
CTA of the Carotids: Recommended scan protocol • 64-slice MDCT • 64 x 0.6mm collimation • z-flying focal spot technique • 0.33sec rotation time • AATCM • 72mAs(base) • 120kV • CM: 90ml 400mgI/ml • 30ml @ 4.5ml/s • 60ml @ 2.5ml/s • 30ml Saline @ 2.5ml/s • Infusion via right arm (artefacts) • Bolus triggering (160 HU / aA) • ECG triggering @ Stanford Type A
CTA of the Carotids: Recommended scan protocol • 64-slice MDCT • 64 x 0.6mm collimation • z-flying focal spot technique • 0.33sec rotation time • AATCM • 72mAs(base) • 120kV • CM: 90ml 400mgI/ml • 30ml @ 4.5ml/s • 60ml @ 2.5ml/s • 30ml Saline @ 2.5ml/s • Infusion via right arm (artefacts) • Bolus triggering (160 HU / aA) • ECG triggering @ Stanford Type A Single Bolus Split Bolus
CT Angiography - Head Circle of Willis Vascular Malformations Aneurysms
3-mm aneurysm in MCA, at the origin of L’t anterior temporal artery.
Ideal imaging modality for aneurysm detection and characterization: • Non-invasive. • Easy to perform. • Reproducible. • Readily available. • Minimal complications. • High degree of accuracy.
Intracerebral haemorrhage on CT • Is always seen • apparent immediately • lasts 1 week • then disappears and looks like an infarct
Intracerebral Haemorrhage • Usually caused by hypertension • thickening & weakening of walls of small arteries/arterioles • formation of small aneurysms • rupture produces a large blood filled cavity that acts as a SOL • typically basal ganglia or thalamus
Ischaemic stroke on CT • Infarcts seen as areas of hypodensity • become more obvious as time progresses • small infarcts appear later than large ones • overall, 40% strokes have normal CT • posterior fossa difficult
Cerebral Infarction • Infarction is caused by failure of blood flow to a region • damage to the brain is due to: • ischaemia • oedema surrounding the ischaemic area • sources of occlusion of vessels: • thrombosis of small vessels - hypertensive lipohyalinosis - lacunar infarcts • thrombosis of larger vessels • embolus from extracranial vessels or heart
Question 1: Mr Y A 72 year old lady with known bladder cancer (transitional cell carcinoma) presents with mild left sided weakness. CT scan
What’s the diagnosis? Right frontal lesion is a primary intracerebral haemorrhage stroke The left frontal lesion is an incidental meningioma Lessons Stroke affects older people and co-morbidity is common About 10% of all stroke is due to primary intracerebral haemorrhage
Pathology of stroke can now be reliably established by CT scanning done within hours/days of the event Cerebral infarction 80% Primary intracerebral haemorrhage 10% Subarachnoid haemorrhage 5% Unknown 5% Sudlow & Warlow 1997 Systematic review of world-wide incidence studies
Question 2 64 year old man was driving his car and he suddenly lost power in his right arm and leg He had no headache No loss of consciousness Called for help and son brought him to casualty No significant medical history
On examination Looked well Blood pressure 200/120 mmHg Normal language Slurred speech Complete weakness affecting his right face, arm and leg No hemianopia
Question 3: 85 year old lady Presents with a sudden onset of dizziness and headache On examination she had nystagmus Six hours after admission started to complain of worsening headache 24 hours later was unconscious Is this a stroke?
Question 4 Mrs X 69 years old Developed Right hemiparesis and aphasia during breakfast (9am) Husband called GP and sent immediately to A & E department
Severe (0/5) right face, arm and leg weakness Dyspraxia (disorganised movement of body) Aphasic (no understanding or expression of language)
Is this a stroke? Dense MCA sign indicating thrombus in the left MCA Yes!