Mobile Stroke Unit Project – Smart, Gentle, and Sustainable-

About Mobile Stroke Units (MSUs)

A Mobile Stroke Unit (MSU) is a doctor car equipped with a dedicated head X-ray CT scanner and a telecommunications system that can be mounted in an ambulance. It enables rapid diagnosis and initiation of treatment for stroke at the scene of an emergency call or at the point where it meets an ambulance. Recent clinical comparative studies have demonstrated that the reduction in time from onset to diagnosis and initiation of treatment by MSUs leads to better outcomes for stroke patients, along with cost-effectiveness.

 The first MSU (Mechanical Storage Unit) was put into operation in 2008 in Homburg, a provincial city in southwestern Germany, by Professor Klaus Fassbender (Saarland University). Its effectiveness was reported in 2012, and it was put into operation in Berlin as well. Since then, MSUs have spread mainly in major cities in the United States, and in recent years, their introduction has progressed in Thailand and China. It is reported that by the end of 2025, there will be about 100 units in operation in 17 countries worldwide.

The X-ray CT scanner installed in the MSU is dedicated to the head and, in addition to simple CT, is also capable of angiography (CTA) and cerebral perfusion imaging (CTP). In recent years, development of head CT scanners using microwave technology has also progressed, and it is expected that they will be installed in regular ambulances and helicopters in the future.

Treatment in MSUs primarily involves thrombolytic therapy for cerebral infarction, and currently, in addition to alteplase, tenecteplase is also being studied internationally. Clinical trials for very early intervention are ongoing for cerebral hemorrhage. Furthermore, MSUs are expected to be applied to traumatic brain injuries, and close cooperation between stroke and emergency medicine departments is crucial for their implementation. As an operational model in regional cities, the concept of Hybrid MSUs has been proposed, and verification studies are underway, mainly in Europe.

In Japan, we took the lead in establishing the MSU project team in 2012, and have been working towards the introduction and operation of the system, but so far this has not been realized. Details are summarized in the paper mentioned below. Currently, we are working in cooperation with relevant organizations to consider the institutional framework (pharmaceutical approval framework) for in-vehicle CT scanners, which is the most important issue for introduction.

In the latest US guidelines for the initial treatment of acute ischemic stroke, published in January 2026, thrombolytic therapy with MSUs was classified as Class I, Level of Evidence A. In Japan's "Third Five-Year Plan for Overcoming Stroke and Cardiovascular Disease," published in March 2026, a direction toward introducing MSUs was also indicated. Against this backdrop, we are currently requesting the establishment of working groups within relevant academic societies.

Based on our philosophy of "earlier diagnosis and treatment initiation for stroke, and better treatment outcomes," we aim to introduce MSUs to areas where they are needed, and are working to resolve the challenges necessary for their continuous operation.

March 2026, Masahiko Hiroki

Research Outputs

• “Nationwide Questionnaire Survey on Mobile Stroke Unit - Challenges and Prospects”
  Masahiko Hiroki, Motoshi Kono, Masaki Misawa Journal of the Japanese Society of Emergency Medicine: Survey and Report 2022 Volume 25, Issue 4, p. 694-703

• “Issues and prospects for the introduction and operation of MSU in Japan”
  Masahiko Hiroki, Motoshi Kono, Masaki Misawa Journal of the Japanese Society of Emergency Medicine: Review 2022 Vol. 25 No. 5 p. 767-781

• "Latest trends in mobile stroke unit and its in-vehicle diagnostic equipment"
  Masahiko Hiroki, Yutaka Kono, Masaki Misawa Stroke: Review 2023 Vol. 45 No. 5 p. 369-380

• “Mobile stroke unit: Usefulness and problem solving in Japan”
  Masahiko Hiroki, Masaki Misawa Japanese Clinical Practice: Review 2023 Vol. 81 No. 9 p. 1425–1433

• Practical Status and Social Background of Current Mobile Stroke Units Worldwide: A Survey and Investigation.
• Hiroki Masahiko, Kohno Mototsugu, Kohno Yutaka, Misawa Masaki.
• West J Emerg Med. 2025 May 19;26(3):700-711.

Click here for the project video (CT-equipped ambulance simulation)

Return to information list