Feasibility of the photoacoustic detection of haemophilia-related microbleeds: a preclinical study using isolated pig limbs

Recent advancements in haemophilia treatment have dramatically reduced the frequency of symptomatic bleeding. However, minor, asymptomatic bleeding may contribute to the progression of joint damage and decrease quality of life. Detecting small amounts of blood with minimal flow is difficult using existing testing methods, necessitating the development of new diagnostic approaches. To determine whether tiny amounts of blood injected subcutaneously, intramuscularly, and intra-articularly can be detected in a pig to assess the feasibility of detecting microbleeds in people with haemophilia. Pig whole blood was injected subcutaneously, intramuscularly, and intra-articularly into the isolated hind limbs of pigs. Photoacoustic imaging (PAI) was performed using an Acoustic X device (CYBERDYNE INC, Tsukuba, Japan) to detect blood signals. Following the injection of 200 µL of blood, conventional ultrasound imaging revealed no discernible changes, such as echo-free spaces. Conversely, on PAI, a signal indicating the presence of blood was detected. We have demonstrated that even very small amounts of nonflowing blood injected into the subcutaneous tissue, muscle, and joint of the hind limbs of pigs can be detected using PAI. We believe that the results of this study show the potential of this technique for detecting microbleeds in people with haemophilia. Not applicable.