Guidelines for Management of Ischaemic Stroke 2008 - ESO

More documents

Recommendations

Info

ESO-Guidelines for Management of Ischaemic Stroke 2008 Some centres prefer to use MRI as first line routine investigation for acute stroke. MRI with diffusion-weighted imaging (DWI) has the advantage of higher sensitivity for early ischaemic changes than CT [130]. This higher sensitivity is particularly useful in the diagnosis of posterior circulation stroke and lacunar or small cortical infarctions. MRI can also detect small and old haemorrhages for a prolonged period with T2* (gradient echo) sequences [143]. However, DWI can be negative in patients with definite stroke [144]. Restricted diffusion on DWI, measured by the apparent diffusion coefficient (ADC), is not 100% specific for ischaemic brain damage. Although abnormal tissue on DWI often proceeds to infarction it can recover, which indicates that DWI does not show only permanently damaged tissue [145, 146]. Tissue with only modestly reduced ADC values may be permanently damaged; there is as yet no reliable ADC threshold to differentiate dead from still viable tissue [147, 148]. Other MRI sequences (T2, FLAIR, T1) are less sensitive in the early detection of ischaemic brain damage. MRI is particularly important in acute stroke patients with unusual presentations, stroke varieties, and uncommon aetiologies, or in whom a stroke mimic is suspected but not clarified on CT. If arterial dissection is suspected, MRI of the neck with fat suppressed T1-weighted sequences is required to detect intramural haematoma. MRI is less suited for agitated patients or for those who may vomit and aspirate. If necessary, emergency life support should be continued while the patient is being imaged, as patients (especially those with severe stroke) may become hypoxic while supine during imaging [124]. The risk of aspiration is increased in the substantial proportion of patients who are unable to protect their airway. Perfusion imaging with CT or MRI and angiography may be used in selected patients with ischaemic stroke (e.g. unclear time window, late admission) to aid the decision on whether to use thrombolysis, although there is no clear evidence that patients with - 22 -
ESO-Guidelines for Management of Ischaemic Stroke 2008 particular perfusion patterns are more or less likely to benefit from thrombolysis [149- 152]. Selected patients with intracranial arterial occlusion may be candidates for intra-arterial thrombolysis, although there is only limited evidence to support this [153, 154]. Patients with combined obstructions of the internal carotid artery (ICA) and MCA have less chance of recovering with intravenous thrombolysis than patients with isolated MCA obstructions [155]. In patients with MCA trunk occlusions, the frequency of severe extracranial occlusive disease in the carotid distribution is high [156, 157]. Mismatch between the volume of brain tissue with critical hypoperfusion (which can recover after reperfusion) and the volume of infarcted tissue (which does not recover even with reperfusion) can be detected with MR diffusion/perfusion imaging with moderate reliability [158], but this is not yet a proven strategy for improving the response to thrombolysis up to 9 hours [159]. There is disagreement on how to best identify irreversible ischaemic brain injury and to define critically impaired blood flow [149, 152, 160]. Quantification of MR perfusion is problematic [161], and there are widely differing associations between perfusion parameters and clinical and radiological outcomes [149]. Decreases in cerebral blood flow on CT are associated with subsequent tissue damage [150, 151], but the therapeutic value of CT perfusion imaging is not yet established. Although infarct expansion may occur in a high proportion of patients with mismatch, up to 50% of patients without mismatch may also have infarct growth and so might benefit from tissue salvage [152, 162]. The “imaging/clinical” mismatch, i.e. the mismatch between the extent of the lesion seen on DWI or CT and the extent of the lesion as expected from the severity of the neurological deficit, has produced mixed results [163, 164]. Hence, neither perfusion imaging with CT or MRI nor the mismatch concept can be recommended for routine treatment decisions. Microhaemorrhages are present on T2 * MRI in up to 60% of patients with haemorrhagic stroke, and are associated with older age, hypertension, diabetes, leukoaraiosis, lacunar stroke, and amyloid angiopathy [165]. The incidence of symptomatic intracranial haemorrhage following thrombolysis in ischaemic stroke - 23 -
Page 1 and 2: Guidelines for Management of Ischae
Page 3 and 4: ESO-Guidelines for Management of Is
Page 21: ESO-Guidelines for Management of Is
Page 73 and 74:
ESO-Guidelines for Management of Is
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
show all

Guidelines for Management of Ischaemic Stroke 2008 - ESO

Create successful ePaper yourself

Delete template?

Save as template?