Review of systems for the detection and monitoring of accumulated fluids in the human torso

A fluid buildup in the torso, such as inside the lungs (pulmonary edema) or around the lungs (pleural effusion), is among the common symptoms of various diseases such as cancers, and heart and liver failures. The chest X-ray and computer tomography (CT)-scan are the most widely used non-invasive devices for the detection of the accumulated fluid. Due to the high cost and ionizing radiation of the aforementioned diagnostic tools, there has been huge research efforts to design alternative tools that are non-invasive, efficient, low-cost and safe for long term monitoring. This paper presents a brief review of the recently proposed systems for the detection of torso fluid accumulation using different modalities. This review indicates that microwave-based imaging systems are the most promising technique as a diagnostic tool of this serious medical condition.