Osamu Arai

Reproducible Surveillance Breast Ultrasound Using an Image Fusion Technique in a Short-Interval Follow-up for BI-RADS 3 Lesions: A Pilot Study

The aim of our study was to verify the utility of surveillance ultrasound (US) using real-time virtual sonography (RVS)--to coordinate present US images with past US images reconstructed from previously acquired US volume data using an image fusion technique--for short-interval follow-up of Breast Imaging-Reporting and Data System (BI-RADS) category 3 mass lesions. We enrolled 20 women (23 lesions) with more than 24 mo of follow-up after classification as BI-RADS category 3 during initial US. US surveillance was scheduled at 6, 12 and 24 mo. Measurement of the target lesion diameter was performed after the probe was adjusted to include the maximum diameter of a past US image at each visit. RVS was technically successful in 100% of patients. All target lesions were detected, including two iso-echoic lesions. The mean target lesion diameters at baseline and at 6, 12 and 24 mo were 8.2 ± 4.2, 8.4 ± 4.5, 8.1 ± 4.5 and 8.3 ± 5.0 mm, respectively (p = 0.785). Our results suggest that RVS is a reproducible, operator-independent technique for comparison of US images of BI-RADS category 3 mass lesions obtained at different time points.

The Integration of Computed Topography Imaging in Ultrasound Diagnosis: Real-Time Virtual Sonography

Ultrasound imaging in medicine is a noninvasive and convenient examination method. The probe for the ultrasound scanner is manipulated freehand during examination, so the cross-sectional image is a little less objective compared to other modalities. In addition, the cross-sectional image is not parallel to the body, and hence it is difficult to compare ultrasound images and computed tomography (CT) images. When the doctor makes the comparison between these two kinds of images for diagnosis or interventional operation, he feels some stress. We thought this situation should be improved, so we developed a new technology that combines CT images to ultrasound images. This system enables side-by-side display of CT multiplanar reconstruction (MPR) images obtained from CT volume data and the same cross-sectional ultrasound images in real time. We named it as real-time virtual sonography (RVS).