Multiresolution discrete optimization registration method of ultrasound and magnetic resonance images based on key points / 生物医学工程学杂志

The registration of preoperative magnetic resonance (MR) images and intraoperative ultrasound (US) images is very important in the planning of brain tumor surgery and during surgery. Considering that the two-modality images have different intensity range and resolution, and the US images are degraded by lots of speckle noises, a self-similarity context (SSC) descriptor based on local neighborhood information was adopted to define the similarity measure. The ultrasound images were considered as the reference, the corners were extracted as the key points using three-dimensional differential operators, and the dense displacement sampling discrete optimization algorithm was adopted for registration. The whole registration process was divided into two stages including the affine registration and the elastic registration. In the affine registration stage, the image was decomposed using multi-resolution scheme, and in the elastic registration stage, the displacement vectors of key points were regularized using the minimum convolution and mean field reasoning strategies. The registration experiment was performed on the preoperative MR images and intraoperative US images of 22 patients. The overall error after affine registration was (1.57 ± 0.30) mm, and the average computation time of each pair of images was only 1.36 s; while the overall error after elastic registration was further reduced to (1.40 ± 0.28) mm, and the average registration time was 1.53 s. The experimental results show that the proposed method has prominent registration accuracy and high computational efficiency.

Success rate of one-stop procedure for atrial fibrillation ablation and its impact on cardiac function: a propensity-matched study / 南方医科大学学报

OBJECTIVE@#To investigate the effect of the combination of atrial fibrillation (AF) ablation and left atrial appendage closure (LAAC) on cardiac function and the success rate of AF ablation.@*METHODS@#We retrospectively analyzed the data of 56 patients with AF undergoing a one-stop procedure for AF ablation and LAAC in our hospital between May, 2015 and May, 2019. Propensity score matching (PSM) at the ratio of 1:1 was used to select 56 control patients undergoing AF ablation at high risk of stroke, for matching with the hybrid procedure group. The perioperative complications, thromboembolic events, recurrence of atrial arrhythmia and cardiac function were compared between the groups.@*RESULTS@#The two groups of patients were comparable for age, gender, BMI, duration and type of AF, concomitant diseases, CHA2DS2-VASc and HAS-BLED scores (@*CONCLUSIONS@#The combination of AF ablation and LAAC is safe but does not improve the success rate of AF ablation. The one-stop procedure can improve cardiac function of the patients, but AF ablation alone can achieve better improvement of cardiac function.