Bladder Volume Estimation Using 3-D Electrical Impedance Tomography Based on Fringe Field Sensing

Clinically, dynamic monitoring of bladder volume is of great significance for patients with bladder diseases. This article proposes a method for the continuous monitoring of bladder volume by 3-D electrical impedance tomography (EIT). To facilitate convenient installation and maintenance for patients, a single-layer half-circle EIT sensor is proposed and designed to be attached at the top of the full bladder for 3-D imaging, based on fringe field sensing. By incorporating the simple prior knowledge of the approximate position and maximum extension region of a full bladder in the abdomen, a dedicated sparse representation algorithm was proposed to alleviate the ill-posedness of 3-D reconstruction and improve the image quality. Bladder volume is finally estimated based on the 3-D image with improved accuracy. The effectiveness of the proposed method is verified by simulation and human trials. Results show that this method is able to reconstruct a 3-D image of the bladder, and the estimation errors of volume are less than 8% in the human trials, which is accurate enough for patients nursing. This provides a promising alternative for the dynamic monitoring of bladder volume.