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During magnetic resonance imaging (MRI), measurements of arterial blood pressure can provide valuable information about the status of the patient under investigation. However, due to the strong magnetic fields used in MRI, normal non-invasive blood pressure equipment cannot be used during these examinations. This study aims to evaluate the function and calibration of a non-invasive sphygmomanometer, the CareTaker4. The CareTaker4 estimates blood pressure by measuring the pressure in the finger using a finger cuff and an air tube that propagates the pressure to the device. The device can then be placed outside the MRI examination room, outside the influence of magnetic fields. By understanding how the system works and what factors affect its reliability, we can optimize the use of CareTaker4 to reliably monitor the patient's blood pressure during magnetic resonance imaging. This project aimed to develop a measurement setup and code for analyzing the data signals given by the CareTaker4 system, to understand and evaluate the functionality of this non-invasive pressure system. 

To do this, an experiment was carried out with a test group consisting of 5 participants. The blood pressure was measured with the CareTaker4 for 15 minutes, while the raw pressure signal in the tubing was measured with an external pressure sensor. Signals generated from the CareTaker4 were documented while the pressure sensor data was recorded with a measuring station. Data analysis and interpretation were then executed in MatLab. The relationship between the measured pressure signal and the signals generated by the CareTaker4 system was then examined. As a second test, the actual blood pressure estimations provided by the CareTaker4 system were also compared to a reference value taken with a regular blood pressure monitor before and just after the experiment. 

Our results showed that the experimental setup allowed for measurement of the pressure in the tubing connecting the CareTaker4 to the patient and that these measured signals corresponded fairly well with the raw signals exported by the CareTaker4, although more work is needed to fully match the two data sets (e.g., choosing the correct filtering etc). The measured blood pressures were in agreement between the CareTaker4 and the reference (arm cuff). The methods we used and the code that was developed could thus successfully generate a close-up view of how the pulse pressure changes over time during measurements and could be expanded to further understand and subsequently validate the CareTaker4 system under different measurement situations.