Low signal, high noise and large uncertainty make CT perfusion unsuitable for acute ischemic stroke patient selection for endovascular therapy
- 1Department of Neuroradiology, Massachusetts General Hospital, Boston, Massachusetts, USA
- 2Harvard Medical School, Boston, Massachusetts, USA
- Correspondence to Dr R G González, Department of Neuroradiology, Massachusetts General Hospital, Boston, Massachusetts, 02114 USA;
- Accepted 2 May 2012
Introduction: I was wrong
Neurointerventionists are on the cusp of revolutionizing the care of the acute ischemic stroke patient. The stage is set for a major advance after 2 decades of experience and the development of extraordinarily effective endovascular devices. This advance depends on a clear demonstration of improved patient outcomes, but the evidence for improved outcomes after endovascular therapy is weak. This was most dramatically demonstrated by the halting of the IMS III trial (ClinicalTrials.gov Identifier: NCT00359424). There is an emerging consensus that the proper selection of patients for endovascular treatment has been lacking. Patient selection using neuroimaging has not been successful, most likely because ineffective neuroimaging methods have been employed.
I have been a strong advocate of using neuroimaging, especially CT perfusion (CTP), for patient selection. CTP is particularly attractive because it can be obtained immediately after non-contrast CT and C without moving the patient. But I was wrong. There is now strong evidence that some neuroimaging methods are effective but others are not. I have learned that the evidence is especially strong for the reliability of diffusion MRI and the unreliability of CTP for measuring the size of the infarct core in the individual patient. In this essay, I review the evidence that led to my current view on the best practices for imaging the stroke patient. My hope is that my education may help neurointerventionists maximally benefit their patients.
Massachusetts General Hospital neuroradiology and interventional neuroradiology consensus conference on advanced neuroimaging of stroke physiology for neurointervention
The greatest opportunity to improve overall outcomes in ischemic stroke is the successful treatment of patients with occlusion of major cerebral arteries. The vast majority of these patients involve occlusion of the proximal middle cerebral artery (MCA), and this condition will be the focus of this essay. Figure 1 illustrates the altered physiology produced by a right MCA occlusion. With occlusion, there is an immediate alteration in cerebral hemodynamics that is simultaneously …