This is a prospective, open, multicentre trial that will enrol patients with clinical signs of stroke in the acute phase admitted for CT scan. The investigator will assess and control the inclusion/exclusion criteria. If the patient is confirmed to be suitable for the trial, the patient is asked to give oral informed consent. If the answer is affirmative the microwave measurement will be performed. The procedure will take less than five minutes (the duration of the actual measurement procedure is 1.5 minutes) and will not interfere with the patient's standard of care during the hospital stay. Written informed consent is acquired by the investigator, as soon as possible after the acute phase of care is completed.

The measurement data will be evaluated for the presence of signal artifacts. The diagnostic ability of the device will be evaluated using a leave-one-out cross validation (LOOCV) method with the CT diagnosis as ground truth.

Safety will be evaluated throughout the trial, and a safety follow-up will be performed by the investigator 24 hours after the last microwave measurement. No further follow-up of patients is planned.