# Advancements in diagnostic and interventional radiology for stroke treatment: the path from trial to bedside through the pre-MR CLEAN, MR CLEAN, and MR CLEAN II eras

## TL;DR

This paper discusses how diagnostic and interventional radiology transformed stroke treatment through key trials, leading to improved patient outcomes.

## Contribution

The paper highlights the novel impact of MR CLEAN and MR CLEAN II trials on stroke treatment guidelines and clinical practice.

## Key findings

- Endovascular treatment for anterior circulation large vessel occlusions significantly reduces disability.
- Computed tomography angiography or magnetic resonance angiography became standard in acute stroke workup.
- Collaboration between disciplines accelerated clinical implementation of stroke treatments.

## Abstract

The stroke field is inevitably connected with imaging in which radiologists fulfill a central role. Our landmark MR CLEAN trial led to the implementation of baseline computed tomography angiography or magnetic resonance angiography in the acute stroke workup and subsequent endovascular treatment (EVT) for ischemic stroke patients with a large vessel occlusion in the anterior circulation, resulting in numerous patients worldwide currently being treated often successfully. A reversal of the pathophysiologic process behind an acute cerebrovascular event was made possible. Subsequently, in the MR CLEAN II trials, the clinical impact of both diagnostic and interventional radiologists remained a cornerstone of our research, which means value-based radiology. Within these MR CLEAN II trials, we proved that aspirin and heparin during EVT should be avoided due to increased symptomatic intracranial hemorrhage risk (MR CLEAN-MED). We concluded there is additional benefit of EVT in the 6-to-24-h window after stroke in the presence of good collaterals on baseline CTA (MR CLEAN-LATE). The impactful success of our stroke trials that changed many guidelines was mainly attributable to (1) the societal burden of the disease, with two thirds of patients dying or being independent at 3 months; (2) the fact that stroke is a common disease, (3) the relatively simple and pragmatic approach of the trials resembling real-world setting; (4) the acceleration of implementation in clinical practice facilitated by a structured approach to guideline development and conditional funding; and foremost (5) the excellent collaboration on a professional level between-disciplines, i.e., diagnostic radiologists, interventionalists, and neurologists.

Critical relevance statement The MR CLEAN and MR CLEAN II trials have had tremendous impact on clinical practice, directly by more patients being treated with an effective intervention and indirectly through adoption of evidence-based guidelines. It is in this setting of stroke treatment that diagnostic and interventional radiologists have played a crucial role and created clinical impact.

• Endovascular treatment for stroke caused by a large vessel occlusion in the anterior circulation reduces disability significantly.

• Our landmark MR CLEAN trial led to the implementation in daily practice of computed tomography angiography or magnetic resonance angiography in the acute stroke workup and subsequent endovascular treatment.

• The key to a successful trial and fast implementation in clinical practice was the excellent collaboration between disciplines, i.e., radiologists and neurologists, in all stroke centers in the Netherlands.

• Performance of a multicenter trial, multidisciplinary guideline adaptation recommending endovascular treatment, and reimbursement were important steps resulting in treatment of 8% of all ischemic stroke patients annually.