The Application of Knowledge Distillation toward Fine-Grained Segmentation for Three-Vessel View of Fetal Heart Ultrasound Images.

Objectives: Measuring anatomical parameters in fetal heart ultrasound images is crucial for the diagnosis of congenital heart disease (CHD), which is highly dependent on the clinical experience of the sonographer. To address this challenge, we propose an automated segmentation method using the channel-wise knowledge distillation technique. Methods: We design a teacher-student architecture to conduct channel-wise knowledge distillation. ROI-based cropped images and full-size images are used for the teacher and student models, respectively. It allows the student model to have both the fine-grained segmentation capability inherited from the teacher model and the ability to handle full-size test images. A total of 1,300 fetal heart ultrasound images of three-vessel view were collected and annotated by experienced doctors for training, validation, and testing. Results: We use three evaluation protocols to quantitatively evaluate the segmentation accuracy: Intersection over Union (IoU), Pixel Accuracy (PA), and Dice coefficient (Dice). We achieved better results than related methods on all evaluation metrics. In comparison with DeepLabv3+, the proposed method gets more accurate segmentation boundaries and has performance gains of 1.8% on mean IoU (66.8% to 68.6%), 2.2% on mean PA (79.2% to 81.4%), and 1.2% on mean Dice (80.1% to 81.3%). Conclusions: Our segmentation method could identify the anatomical structure in three-vessel view of fetal heart ultrasound images. Both quantitative and visual analyses show that the proposed method significantly outperforms the related methods in terms of segmentation results.

Radiofrequency ablation for primary hyperparathyroidism and risk factors for postablative eucalcemic parathyroid hormone elevation.

OBJECTIVE: To investigate the efficacy of radiofrequency ablation (RFA) as a treatment option for primary hyperparathyroidism (pHPT) and risk factors for postablative eucalcemic parathyroid hormone elevation (ePTH). METHODS: This retrospective study included 51 patients with pHPT who underwent RFA. The patients were divided into the ePTH and normal PTH groups, based on the serum intact parathyroid hormone (iPTH) level one month after ablation. Serum iPTH, calcium, and phosphorus levels, and the volume reduction rates (VRR) of the parathyroid glands were compared between the groups at each follow-up point. Risk factors for ePTH at one month after ablation were examined. RESULTS: After RFA, one (2%) patient had persistent pHPT, and 50 (98%) patients were cured. The incidence rates of ePTH at 1, 3, 6, and 12 months were 48%, 30%, 20%, and 16%, respectively. Serum iPTH levels in the ePTH group were higher than those in the normal PTH group at each follow-up point (all p < 0.05), except 1 day after ablation (p > 0.05). Serum calcium and phosphorus levels, and the VRR of the glands were comparable in both groups at each follow-up point (all p > 0.05), except for calcium levels 3 days after RFA (p < 0.05). Baseline iPTH (odds ratio, 1.067; p = 0.045) and calcium (odds ratio, 3.923; p = 0.038) levels were independent risk factors for ePTH 1 month after RFA. CONCLUSIONS: RFA is safe and effective for the treatment of pHPT. Moreover, ePTH occurrence after RFA was associated with baseline iPTH and calcium levels and did not increase the risk of recurrent pHPT.

Efficacy and safety of ultrasound-guided radiofrequency ablation of hyperplastic parathyroid gland for secondary hyperparathyroidism associated with chronic kidney disease.

BACKGROUND: The purpose of this study was to determine if ultrasound-guided radiofrequency ablation (RFA) of hyperplastic parathyroid glands could be used to treat secondary hyperparathyroidism (HPT) in patients with chronic kidney disease. METHODS: RFA of the hyperplastic parathyroid glands was performed in 34 patients with secondary HPT. Intact parathyroid hormone (iPTH), calcium, and phosphorus were measured. The outcome was based on the ablation extent (ie, 4, 3, and 1-2 glands). RESULTS: The iPTH, calcium, and phosphorus levels decreased in all groups after RFA. One year after ablation, these parameters remained significantly lower in the 4-gland ablation group compared with the 3-gland and 1 to 2-gland groups. The same tendency was observed for the symptom score. The iPTH levels of <272 pg/mL on the day after ablation was the best predictor for maintaining parathyroid hormone (PTH) levels in a reasonable range 1 year after ablation. CONCLUSIONS: RFA of hyperplastic parathyroid glands for treating secondary HPT is feasible in selected patients. © 2016 Wiley Periodicals, Inc. Head Neck 39: 564-571, 2017.