This paper deals with the possibility of adopting microwave imaging to continuously monitor a patient after the onset of a brain stroke, with the aim to follow the evolution of the disease, promptly counteract its uncontrolled growth, and possibly support decisions in the clinical treatment. In such a framework, the assessed techniques for brain stroke diagnosis are indeed not suitable to pursue this goal. Conversely, microwave imaging can provide a diagnostic tool able to follow up the disease’s evolution, while relying on a relatively low cost and portable apparatus. The proposed imaging procedure is based on a differential approach which requires the processing of scattered field data measured at different time instants. By means of a numerical analysis dealing with synthetic data generated for realistic anthropomorphic phantoms, we address some crucial issues for the method’s effectiveness. In particular, we discuss the role of patient-specific information and the effect of inaccuracies in the measurement procedure, such as an incorrect positioning of the probes between two different examinations. The observed results show that the proposed technique is indeed feasible, even when a simple, nonspecific model of the head is exploited and is robust against the above mentioned inaccuracies. 1. Introduction A brain stroke occurs when cerebral blood circulation fails as a consequence of a blocked or burst blood vessel, causing a ischemia or an hemorrhage, respectively. Currently, stroke is the second cause of mortality worldwide and a major cause of permanent disability [1]. Moreover, because of the ageing population, such a burden is expected to increase in the future, with a significant, also economical, impact on health-care systems [2]. In such a framework, the most assessed diagnostic tools are magnetic resonance imaging (MRI) and computerized tomography (CT), which provide highly reliable images and indeed play a primary role in stroke management protocols [3]. In the recent years, with the aim to further enhance recovery rate and reduce consequences of strokes, continuous postevent monitoring of physiological parameters in the acute stage has gained an increasing importance [4, 5]. As a matter of fact, recovery and treatment depend on close clinical observation, especially during the first few hours after the onset of stroke [6]. However, CT and MRI cannot contribute to pursue this goal, because they are time consuming, not portable, and cost-ineffective. Moreover, CT uses ionizing radiations, which are harmful for the patient's health and hence
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