State of the Art Stroke Imaging: A Current Perspective

 Why do you need these extremely slow imaging technologies? TIME IS BRAIN  you know.

Maybe you want these much faster objective diagnosis options.

Hats off to Helmet of Hope - stroke diagnosis in 30 seconds; February 2017

 

Microwave Imaging for Brain Stroke Detection and Monitoring using High Performance Computing in 94 seconds March 2017

 

New Device Quickly Assesses Brain Bleeding in Head Injuries - 5-10 minutes April 2017

Ski-Mask Design AIR Coil Offers Whole-Brain Imaging Without Claustrophobia

The latest here:

State of the Art Stroke Imaging: A Current Perspective

Rosalie McDonough, MD, Johanna Ospel, MD, Mayank Goyal, MD, PhD

First Published September 27, 2021 Review Article Find in PubMed 

https://doi.org/10.1177/08465371211028823

Article information

Abstract

Acute stroke is a widespread, debilitating disease. Fortunately, it also has one of the most effective therapeutic options available in medicine(Now that is a complete lie, unless of course you expect survivors to accept your fucking tyranny of low expectations!), endovascular treatment. Imaging plays a major role in the diagnosis of stroke and aids in appropriate therapy selection. Given the rapid accumulation of evidence for patient subgroups and concurrent broadening of therapeutic options and indications, it is important to recognize the benefits of certain imaging technologies for specific situations. An effective imaging protocol should: 1) be fast,(How fast to get to 100% recovery?) 2) easily implementable, 3) produce reliable results, 4) have few contraindications, and 5) be safe, all with the goal of providing the patient the best chance of achieving a favorable outcome. In the following, we provide a review of the currently available imaging technologies, their advantages and disadvantages, as well as an overview of the future of stroke imaging. Finally, we offer a perspective.

Keywords

acute stroke, diagnostic imaging, computed tomography, evidence-based medicine, endovascular treatment

Acute ischemic stroke (AIS) is a widespread, debilitating disease, globally affecting approximately 9.5 million people per year.¹ In the US and Canada, it is a leading cause of death and disability.² Fortunately, it also has one of the most effective therapeutic options available in medicine, endovascular treatment (EVT), with an astonishingly low number needed to treat of 2.6 for patients with large vessel occlusions (LVO).³ Prior to EVT, intravenous (IV) thrombolytics comprised the standard of care and, currently, if patients are eligible, both are often used in combination to achieve and maintain vessel patency.⁴

The AIS population is heterogenous, however in the Canadian-led HERMES meta-analysis of the large EVT trials^5-9 (one of which was also Canadian-led), the investigators did not identify any subgroups in which the treatment was not effective.¹⁰ These initial trials, however, involved highly selected patient cohorts and were thus able to show a clear benefit, albeit at the cost of excluding many patients who may have benefited from treatment.^7,11 Since then, many trials have been done or are being conducted on patients who fall outside of these strict inclusion criteria. The BASICS (ClinicalTrials.gov Identifier: NCT01717755) and BEST¹² trials examined the effect of EVT on vertebrobasilar occlusions versus best medical management and found no significant difference in patient outcome, in contrast to a registry-based study.¹³ However, both trials were relatively small and limited to crossover, and there was no evidence of a detrimental effect of EVT. The late window trials DAWN and DEFUSE 3 used CTP and MRI-based imaging criteria to show the efficacy of EVT in patients presenting beyond the 6-hour time window,^14,15 which have been adopted in many clinics around the world. Recently, the focus has shifted to medium vessel occlusions (MeVOs); data from non-randomized studies suggest that EVT of MeVOs is both possible and safe,^16-19 however high-level evidence from randomized trials is lacking. Furthermore, trials investigating the effect of EVT on outcome in patients with large baseline infarctions and minor stroke are currently underway (SELECT-2 (ClinicalTrials.gov Identifier: NCT03876457), TESLA (ClinicalTrials.gov Identifier: NCT03805308), TENSION (ClinicalTrials.gov Identifier: NCT03094715), LASTE (ClinicalTrials.gov Identifier: NCT03811769) and MOSTE (ClinicalTrials.gov Identifier: NCT03796468)). Researchers often use the term “futile treatment” when referring to EVT that did not lead to an improvement in outcomes, and patient selection criteria are applied to identify patients who are most likely to benefit from EVT, thereby also aiming to keep the “futile” EVT procedures at a minimum. This approach is however problematic, since the decision to treat or not to treat with EVT is made based on available information prior to treatment, and there are several factors after the treatment decision has been made that also influence outcomes, such as reperfusion quality, stroke unit care, and post-stroke complications. Even in cases in which EVT does not lead to an improvement in outcome, the complication rate of the EVT procedure appears to be low and there is no evidence of harm in patients with failed EVT compared to those who are not treated with EVT.²⁰ A synopsis of the current American and Canadian evidence-based imaging-related guideline recommendations can be found in Table 1.

Table 1. Imaging-Related Guideline Recommendations.4,21

Table 1. Imaging-Related Guideline Recommendations.^4,21

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While EVT is highly effective in (re)-opening the vessel, it must be done in a timely manner. Indeed, an estimated 2 million neurons die for every prolonged minute of vessel occlusion, highlighting the acute, time critical nature of this disease (“time is brain”).²² As such, it is crucial to minimize the steps between stroke onset and recanalization.

Acute stroke due to non-traumatic hemorrhage represents 10-15% of all stroke cases, however is associated with higher rates of mortality and morbidity.²³ Imaging plays a major role in the differentiation of diagnosis between AIS and stroke due to hemorrhage and thereby aids in the triage of patients for appropriate therapy selection. It has evolved rapidly over the years, from a simple non-contrast computed tomography (NCCT) scan performed within a week of onset to sophisticated software programs that allow for quasi-immediate automatic brain parenchyma assessment and detection of the occluded vessel. These technological developments are iteratively occurring within an adaptive framework in response to broadening therapeutic indications. At the same time, there has been an increase in imaging technology accessibility, allowing diagnostic stroke workups to be performed at smaller tertiary or more rural clinics. As a result, multiple imaging strategies exist, largely dependent on institutional resources, regional guideline recommendations, and, to some extent, stroke physician preferences. Regardless, the goal has remained the same: to quickly diagnose and appropriately treat the patient for the best chance of achieving a favorable outcome.