Comparison of Accuracies between Real-Time Nonrigid and Rigid Registration in the MRI–US Fusion Biopsy of the Prostate

Magnetic resonance imaging (MRI) is increasingly important in the detection and localization of prostate cancer. Regarding suspicious lesions on MRI, a targeted biopsy using MRI fused with ultrasound (US) is widely used. To achieve a successful targeted biopsy, a precise registration between MRI and US is essential. The purpose of our study was to show any decrease in errors using a real-time nonrigid registration technique for prostate biopsy. Nineteen patients with suspected prostate cancer were prospectively enrolled in this study. Registration accuracy was calculated by the measuring distance of corresponding points by rigid and nonrigid registration between MRI and US, and compared for rigid and nonrigid registration methods. Overall cancer detection rates were also evaluated by patient and by core. Prostate volume was measured automatically from MRI and manually from US, and compared to each other. Mean distances between the corresponding points in MRI and US were 5.32 ± 2.61 mm for rigid registration and 2.11 ± 1.37 mm for nonrigid registration (p < 0.05). Cancer was diagnosed in 11 of 19 patients (57.9%), and in 67 of 266 biopsy cores (25.2%). There was no significant difference in prostate-volume measurement between the automatic and manual methods (p = 0.89). In conclusion, nonrigid registration reduces targeting errors.

Motion Artifact Reduction in Contrast-Enhanced Dual-Energy Mammography – A Multireader Study about the Effect of Nonrigid Registration as Motion Correction on Image Quality

Purpose The technically caused delay between low-energy (LE) and high-energy (HE) acquisitions allows motion artifacts in contrast-enhanced dual-energy mammography (CEDEM). In this study the effect of motion correction by nonrigid registration on image quality of the recombined images was investigated. Materials and Methods Retrospectively for 354 recombined CEDEM images an additional recombined image was processed from the raw data of LE and HE images using the motion correction algorithm. Five radiologists with many years of experience in breast cancer diagnostic imaging compared side-by-side one conventional processed CEDEM image with the corresponding image processed by the motion correction algorithm. Every pair of images was compared based on six criteria: General image quality (1), sharpness of skin contour (2), reduction of image artifacts (3), sharpness of lesion contour (4), contrast of lesion (5), visibility of lymph nodes (6). These criteria were rated on a Likert scale (improvement: + 1, + 2; deterioration: –1, –2). Results The mean ratings concerning criteria 1–5 showed a superiority of the recombined images processed by the motion correction algorithm. For example, the mean rating of general image quality was 0.86 (95 % CI: 0.78; 0.93). Only the mean rating concerning criterion 6 showed an inferiority of the recombined images processed by the motion correction algorithm (–0.29 (–0.46; –0.13)). Conclusion The usage of nonrigid registration for motion correction significantly improves the general image quality and the quality of subordinate criteria on the recombined CEDEM images at the expense of somewhat reduced lymph node visibility in some cases. Key Points: Citation Format

Design and Implementation of a Heating Treatment System for Vitiligo Skin Disease Based on Medical Ultrasound

Vitiligo is relatively common clinically. It is an acquired and persistent skin and mucosal pigment depigmentation disease. As a noninvasive and nonradioactive treatment, high-energy ultrasound has been applied to skin diseases of vitiligo. Treatment achieved good clinical results. This article analyzes the structure of the original medical ultrasound system for vitiligo and finds the deficiencies and missing components of the system. On the basis of the original design scheme, a new structural scheme was designed, which solved the shortcomings of the original system and added missing parts. Subsequently, according to actual application requirements and specific component performance, the schematic design, including audio and video input, output and storage, DDR3, Ethernet, and the design of key circuits, such as power supply modules, are specifically introduced. Later, in the PCB design, the contents including stacking, layout, routing, and simulation of key signals were introduced in detail. The design includes a probe excitation signal generation module, excitation signal parameter control module, high voltage and temperature monitoring module, and corresponding power conversion module. This paper is mainly to develop a vitiligo skin disease heating treatment array system based on the principle of both cost and performance. This paper is based on the nonrigid registration algorithm of the FFD model and HPV interpolation and the nonrigid registration algorithm combining shape information and SIFT method. In the focused ultrasound treatment system, the image-guided positioning and monitoring functions are realized. Studies have shown that when the peak voltage of the transmitter circuit is 55 V, the sound power is 0.28 W. It can be seen that the transmitting circuit system designed in this article is a relatively stable and reliable system, which is suitable for the ultrasound treatment of vitiligo skin diseases.