A new body imaging system that combines rotational ultrasound (RUS) with photoacoustic tomography (PAT) aims to improve body imaging.
Researchers from the University of Southern California (USC) in Los Angeles and the California Institute of Technology in Pasadena created the RUS-PAT system and reported success in a recent study.
In this episode, Charles Liu, MD, PhD, discusses how the system works, the study's results, potential applications for RUS-PAT, and future directions in research. Along with being a co-senior author on the published paper, Liu is a professor of clinical neurological surgery, urology, and surgery at the USC Keck School of Medicine and director of the USC Neurorestoration Center.
Researchers on the project tested RUS-PAT on multiple regions of the human body, including the brain, breast, hand, and foot. The system captured images of both tissue structure and blood vessels across a region up to 10 cm wide and in about 10 seconds.
The researchers have also highlighted benefits of using the system. These include lower costs to build compared to an MRI scanner, avoiding the radiation needed for x-ray and CT scans, and resulting in more sophisticated images than conventional ultrasound.
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
