Evaluation of carotid endarterectomy with sequential MR perfusion imaging: A preliminary 12-month follow up

Gillard, Jonathan H.; Hardingham, Charles R.; Antoun, Nagui M.; Freer, C. E. L.; Kirkpatrick, Peter J.

doi:10.1016/s0009-9260(99)90681-5

Cited by 14 publications

(16 citation statements)

References 49 publications

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“…To the best of our knowledge, this is the first PWI study in patients presenting symptoms of "hyperperfusion" after CEA. A previous MRI perfusion study 7 found early bolus arrival time on the ipsilateral hemisphere in 4 of 7 patients who were asymptomatic after CEA, confirming the common occurrence of the reperfusion hyperemic response. In the present study, the relative hemispheric hyperperfusion ipsilateral to CEA in patients 1 to 4, as evidenced by PWI, was only moderate, ranging from 20% to 44%.…”

Section: Discussionsupporting

confidence: 62%

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Postcarotid Endarterectomy Hyperperfusion or Reperfusion Syndrome

Karapanayiotides

Meuli

Devuyst

et al. 2005

Stroke

147

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Background and Purpose-Hyperperfusion syndrome (HS) after carotid endarterectomy (CEA) has been related to impaired cerebrovascular autoregulation in a chronically hypoperfused hemisphere. Our aim was to provide new insight into the pathophysiology of the HS using magnetic resonance imaging (MRI) studies with diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI). Methods-Five out of 388 consecutive patients presented 2 to 7 days after CEA, partial seizures (nϭ5), focal deficits (nϭ5), and intracerebral hemorrhage (nϭ3). In 4 patients, using sequential examinations, we identified vasogenic or cytotoxic edema by DWI; we assessed relative interhemispheric difference (RID) of cerebral blood flow (CBF) by PWI; and we measured middle cerebral artery mean flow velocities (MCA Vm) by transcranial Doppler (TCD). Results-None of the patients presented pathological DWI hyperintensities, consistent with the absence of acute ischemia or cytotoxic edema. In 2 patients, we found an MRI pattern of reversible vasogenic edema similar to that observed in the posterior leukoencephalopathy syndrome. Middle cerebral artery (MCA) mean flow velocities (Vm) were not abnormally increased at any time. PWI documented a 20% to 44% RID of CBF in favor of the ipsilateral to CEA hemisphere. Conclusions-HS can occur in the presence of moderate relative hyperperfusion of the ipsilateral hemisphere. MCA Vm values may not accurately reflect RID of CBF over the cortical convexity. We suggest that the hemodynamic pathogenetic mechanisms of the HS are more complicated than hitherto believed and that they may be more accurately described by the term "reperfusion syndrome." (Stroke. 2005;36:21-26.)

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Section: Discussionsupporting

confidence: 62%

“…Hitherto, diffusion-weighted imaging (DWI) has been used in very few patients with HS after CEA, 6 and perfusionweighted imaging (PWI) has not been applied to the investigation of the HS. A study 7 evaluated CEA with sequential PWI, but none of the patients had HS.…”

mentioning

confidence: 99%

Postcarotid Endarterectomy Hyperperfusion or Reperfusion Syndrome

Karapanayiotides

Meuli

Devuyst

et al. 2005

Stroke

147

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“…It is expected that this would be transient, but the exact time course cannot be defined by the data presented here. In a recent study, 7 patients were monitored by MRI 1 to 2 days after endarterectomy, and enhancement was not seen at that time. In the present study, no symptoms were reported after the procedure, and thus this proposed enhancement mechanism needs to be distinguished from the hyperperfusion syndrome.…”

Section: Discussionmentioning

confidence: 99%

“…The short-term cerebral effects of direct interventional treatments for carotid stenosis have not been extensively studied, although early reports show improvement of cerebral blood flow after endarterectomy. 7 Chelates of gadolinium, 8 a rare earth metal, are commonly used as an intravenous contrast agent in MRI. In neuroimaging they are used to depict breakdown of the bloodbrain barrier or, with the advent of subsecond scanning times, as a tracer for investigating cerebral perfusion.…”

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confidence: 99%

Unilateral Leptomeningeal Enhancement After Carotid Stent Insertion Detected by Magnetic Resonance Imaging

Wilkinson

Griffiths²,

Hoggard³

et al. 2000

Stroke

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Background and Purpose-Percutaneous transluminal angioplasty combined with vascular stenting is currently being assessed in the treatment of patients with symptomatic, severe carotid stenosis. The immediate cerebral hemodynamic effects resulting from stenting are not fully understood. This article describes a novel finding: abnormal leptomeningeal enhancement after stenting shown by MRI. Methods-Fourteen patients with symptomatic severe carotid bifurcation stenosis underwent MRI within 4 hours before and within 3 hours after attempted carotid stenting. Twelve patients were successfully stented. Part of the MR investigation consisted of the acquisition of T1-weighted images before and after administration of the contrast agent Gd-DTPA, both before and after the procedure. Results-All 12 patients who underwent successful stenting did not have abnormal enhancement of the leptomeninges before stenting but developed unilateral enhancement following intervention but before the second injection of contrast agent. No contrast enhancement was detected in the 2 patients who had the angiographic procedure but were not stented. Conclusions-These findings suggest that abnormal changes to the leptomeningeal vasculature occur during carotid stenting which are not associated with sudden development of neurological symptoms. The anatomic distribution of the enhancement suggests that it is a consequence of the sudden change in brain hemodynamics secondary to the improvement in carotid flow after stenting. Key Words: angioplasty Ⅲ blood-brain barrier Ⅲ carotid stenosis Ⅲ magnetic resonance imaging Ⅲ stenting A therosclerotic carotid stenosis is the leading cause of ischemic stroke in adults. The results of 2 large, multicenter studies have shown the relative advantages of medical and surgical intervention (carotid endarterectomy) in patients with severe, symptomatic carotid stenosis. 1-3 Other interventions aimed at improving blood flow to the brain such as percutaneous transluminal angioplasty 4 and, more recently, the combination of balloon angioplasty and endovascular stent insertion, 5 are also being used to reduce the risk of stroke. Stenting, like angioplasty, has the advantage of being less invasive than surgical intervention and may offer a low incidence of restenosis. 6 The long-term effects of interventional procedures (Ն2 years) have been reported in the case of endarterectomy, will presumably be shortly reported in the case of balloon angioplasty, and are yet to be assessed for stenting.MR has become an invaluable tool for neurological research with use of structural imaging and "functional" techniques such as perfusion-weighted and diffusion-weighted imaging. The short-term cerebral effects of direct interventional treatments for carotid stenosis have not been extensively studied, although early reports show improvement of cerebral blood flow after endarterectomy. 7 Chelates of gadolinium, 8 a rare earth metal, are commonly used as an intravenous contrast agent in MRI. In neuroimaging they are used to depict breakdown...

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“…Additionally, selected symptomatic patients with moderate ICA stenosis may also benefi t from surgical therapy [6] . Currently used risk stratifi cation parameters, luminal stenosis, although a good refl ector of the haemodynamic consequence of ICA stenosis [7] may not refl ect the true burden of disease as outward expansion of the vessel wall can disguise large in situ plaques [8] . This process of remodelling suggests that despite cerebrovascular perfusion being preserved, luminal patency may not adequately refl ect risk of subsequent ischaemic stroke [9] , which is now thought to be more accurately refl ected by plaque burden and composition [10] .…”

Section: Introductionmentioning

confidence: 99%