Microwave Radiometry for Non-Invasive Detection of Vesicoureteral Reflux (VUR) Following Bladder Warming

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Pediatric Urology

Background:

• Vesicoureteral reflux (VUR) is a significant pediatric condition linked to renal scarring.
• Current diagnostic methods for VUR rely on invasive procedures and X-ray imaging.
• There is a critical need for non-invasive VUR detection techniques.

Purpose of the Study:

• To develop and validate a non-invasive approach for detecting VUR.
• To assess the feasibility of radiometric kidney temperature monitoring during bladder warming.
• To establish a safer alternative to current traumatic VUR diagnostic procedures.

Main Methods:

• Design and testing of a 915MHz square slot antenna array for bladder heating.
• Development of an EMI-shielded log spiral microstrip receive antenna for radiometric monitoring.
• Utilizing a high-sensitivity 1.375GHz total power radiometer and power modulation techniques.
• Conducting in vivo porcine experiments to characterize bladder heating and radiometric temperature changes at depth.

Main Results:

• Demonstrated safe and effective heating of the bladder (180mL saline to 40-44°C) without thermal damage to surrounding tissues.
• Successfully detected temperature changes (2-6°C) in a deep-seated 30mL target simulating the kidney in porcine models.
• Confirmed the radiometer's sensitivity to detect temperature variations indicative of VUR.

Conclusions:

• A 915MHz antenna array can safely warm the bladder in vivo.
• A 1.375GHz radiometer system can detect significant temperature rises in deep tissues.
• This non-invasive radiometric method shows high sensitivity for detecting VUR, offering a promising alternative to current diagnostics.