A mobile head CT system is designed to bring brain imaging into the pre-hospital stroke pathway, allowing suspected stroke patients to be scanned before they reach hospital. Siemens Healthineers SOMATOM On.site as an ambulance-integrated scanner that can support detection of brain ischaemia and bleeding, patient triage and treatment decisions. The system can be combined with the Stroke Connect digital platform to share images and clinical data and support remote expert evaluation. The approach is intended to shorten delays between assessment, imaging and transfer to an appropriate stroke centre, while keeping imaging and workflow functions within the mobile stroke unit.
Imaging Moves Into the Pre-Hospital Pathway
Delays remain a central problem in acute stroke care because suspected stroke patients may be transported without a pre-hospital diagnosis. Without that diagnosis, patients may not be transported to the appropriate stroke centre, delaying treatment. Only 18% of stroke patients receive treatment within the first hour.
SOMATOM On.site is designed to move head CT imaging into the ambulance. Installed in a mobile stroke unit, the scanner can acquire head images at the scene and support identification of brain ischaemia and bleeding. The stated aim is to provide information early enough to assist triage and treatment decisions before hospital arrival. Early field diagnosis can also support direct transfer to an appropriate stroke centre rather than relying on transport decisions without imaging.
The system is intended for non-contrast CT, computed tomography angiography and multiphase computed tomography angiography. Siemens Healthineers states that its head CT image quality can support bleeding detection or exclusion and detection of large vessel occlusion at the point of care. A clinical example describes use of mobile CT to support triage of an intracranial haemorrhage patient and the definition of a pre-hospital treatment plan, including blood pressure-lowering medication.
Workflow Links Imaging, Data and Remote Expertise
The mobile scanner is paired with Stroke Connect, a digital platform designed to collect, organise and share clinical data for suspected stroke patients. It includes structured workflows, stroke-scale documentation, image sharing and telemedicine functions. Remote experts can access relevant patient data, allowing clinical input to be provided from the stroke centre while the patient remains in the field.
The platform is also intended to connect ambulance teams with hospital clinicians through end-to-end image transfer and audio and video communication. This is intended to accelerate therapy decisions without compromising care. With imaging and clinical information available to clinicians before arrival, the pathway is designed to support earlier decisions on destination and treatment.
Workflow guidance is also built into the scanner. myExam Companion includes tools intended to standardise protocols and guide the examination, while Scan&GO allows the operator to control the scan through the integrated touch interface while remaining beside the patient. Images can be checked before automated reconstruction, and Recon&GO automates post-processing. These functions are intended to support consistent acquisition and timely delivery of clinical images.
Stroke Connect also has an operational role. Remote access to patient data is intended to allow stroke centres to keep limited specialist staff in hospital while reducing the number of staff required on board. The platform is designed to bring clinical experts remotely to the scene through its data exchange, image sharing and telemedicine functions.
Design Targets Mobile Use and Scan Consistency
SOMATOM On.site is built for fixed installation in an emergency vehicle without the need for rails. A mounted trolley secures the scanner on board, and the system can acquire scans at an incline of up to 5°. The scanner uses a telescopic gantry and integrated positioning accessories intended to simplify placement of suspected stroke patients and support consistent scans in mobile stroke units.
Patient positioning uses a shoulder board to bridge the space between the bed and stretcher, together with a head holder for fixed isocentric placement. A CARE 2D Camera and bore lighting allow the patient to remain visible when radiation shielding covers are in place. The system also incorporates self-shielding intended to reduce scatter radiation outside the hospital environment.
Technical specifications include a 35 cm gantry opening, 0.75 mm spatial resolution and 32-slice acquisition. The scanner uses a Stellar detector, ADMIRE iterative reconstruction and iMAR metal artefact reduction. Siemens Healthineers states that these technologies support sharp images, while intelligent guidance is intended to help users acquire consistent head CT scans when time is critical.
Conclusion
Mobile stroke units equipped with head CT can bring imaging, data sharing and remote clinical input into the pre-hospital pathway. SOMATOM On.site is designed to support brain imaging at the scene, while Stroke Connect links images and clinical information with hospital teams. The system combines ambulance integration, guided scanning and remote workflow functions intended to support earlier triage and treatment decisions. Its use remains subject to local product availability and regulatory requirements, while the described capabilities focus on imaging, workflow and pre-hospital decision support.
Source & Image Credit: Siemens Healthineers
