(The) Process of Elementary Students Action on Climate Change

학위논문(석사) --서울대학교 대학원 :협동과정 환경교육전공,2010.2.Maste

Computer-aided diagnosis system for evaluation of thyroid nodules on ultrasonography: prospective non-inferiority study according to the experience level of radiologists

Purpose: To determine whether a CAD system for the evaluation of thyroid nodules is non-inferior to radiologists with different levels of experience. Materials and Methods: Institutional review board approval and informed consent were obtained for this prospective non-inferiority study. Patients with thyroid nodules with a decisive diagnosis, whether benign or malignant, were consecutively enrolled from November 2017 to September 2018. Three radiologists with different levels of experience (1 month, 4 year, and 7 years) in thyroid ultrasound reviewed the thyroid ultrasound with and without the use of a CAD system. Statistical analyses included non-inferiority testing of the diagnostic accuracy for malignant thyroid nodules between the CAD system and the three radiologists with a non-inferiority margin of 10%, comparison of the diagnostic performance, and the added value of the CAD system on the radiologists. Results: A total of 197 patients (165 patients with a benign nodule [84.8%] and 25 patients with a malignant nodule [15.2%]) were included in the study cohort. The diagnostic accuracy of the CAD system [88.4%, 95% confidence interval (CI) = 82.65–92.53] was non-inferior to that of the radiologists with less experience (1 month and 4 year) on thyroid US (83.03, 95% CI = 76.52–88.02; P < 0.001), whereas it was inferior to that of the experienced radiologist (7 years) (95.76%, 95% CI = 91.37–97.96; P = 0.138). The sensitivity and negative predictive value of the CAD system were significantly higher than those of the less-experienced radiologists, whereas no significant difference was found with the experienced radiologist. A conjunctive combination of grayscale US and the CAD system significantly improved sensitivity and negative predictive value, although specificity and positive predictive value deteriorated for the less-experienced radiologists. Conclusion: The CAD system may offer support for decision-making in the diagnosis of malignant thyroid nodules for operators who have less experience in thyroid US.Docto

Treatment efficacy of radiofrequency ablation for recurrent tumor at the central compartment after hemithyroidectomy

OBJECTIVE. The aim of this study was to evaluate the efficacy of ultrasound (US)-guided radiofrequency ablation (RFA) for recurrent tumor in the central compartment after hemithyroidectomy. MATERIALS AND METHODS. The medical records of patients who underwent RFA for recurrent tumor after hemithyroidectomy between January 2008 and December 2018 were reviewed. Eight patients who underwent RFA for 10 recurrent tumors after hemithyroidectomy were included in our study population. Patients underwent follow-up US 1, 6, and 12 months after treatment and annually thereafter. The tumor volume reduction rate (VRR) was calculated as follows: VRR = ([initial volume - final volume] × 100) / initial volume. All patients were advised to undergo contrast-enhanced CT after tumor ablation. Complete tumor disappearance was defined as no visible treated tumor on follow-up US or CT. RESULTS. Mean tumor VRR was 97.8% ± 7.0% (SD) (range, 77.8?100%). Complete tumor ablation was achieved for all 10 recurrent tumors. Complete disappearance was confirmed in nine recurrent tumors, and one recurrent tumor showed a VRR of 77.8% on US but there was no enhancement on CT. All eight patients achieved no evidence of disease during mean follow-up of 33.0 months. RFA was tolerated by all patients; there were no major complications or procedure-related deaths. One patient experienced transient voice change during RFA. CONCLUSION. RFA can be considered to be an effective and safe alternative treatment method for recurrent tumor in the central compartment after hemithyroidectomy

Efficacy of radiofrequency ablation for recurrent thyroid cancer invading the airways

Objectives: To evaluate the efficacy of radiofrequency ablation (RFA) in patients with recurrent thyroid cancer invading the airways. Methods: We reviewed patients who had undergone RFA for recurrent thyroid cancer in the central compartment after total thyroidectomy between January 2008 and December 2018. All tumors were classified according to their association with the laryngeal structure and trachea. The volume reduction rate (VRR) and complete disappearance rate were calculated, and their differences were determined relative to the association between the tumor and trachea. Complication rates associated with RFA were evaluated. Results: The study population included 119 patients with 172 recurrent tumors. Mean VRR was 81.2% ± 55.7%, with 124 tumors (72.1%) completely disappearing after a mean follow-up of 47.9 ± 35.4 months. The complete disappearance rate of recurrent tumors not in contact with the trachea was highest, followed by tumors forming acute angles, right angles, and obtuse angles with the trachea, and tumors with intraluminal tracheal invasion (p value < 0.001). The overall complication rate was 21.4%. Conclusions: RFA is effective and safe for the local control of recurrent tumors in the central neck compartment after total thyroidectomy, even for tumors invading the airways, and may be considered an alternative to surgical resection. The inverse relationship between RFA efficacy and airway invasion suggests that early RFA may benefit patients with recurrent tumors in the central neck compartment. Key Points: ? RFA achieved a mean VRR of 81.2% ± 55.7% and complete disappearance of 124 tumors (72.1%) after a mean follow-up of 47.9 ± 35.4 months. ? The complete disappearance rate of recurrent tumors not in contact with the trachea was the highest, followed by tumors forming acute angles, right angles, and obtuse angles with the trachea, and tumors with intraluminal tracheal invasion. ? Stent-assisted RFA may be a good alternative for palliative treatment of recurrent tumors with intraluminal tracheal invasion

Clinical practice guidelines for radiofrequency ablation of benign thyroid nodules: a systematic review

Purpose: Thermal ablation is a novel treatment alternative for benign thyroid nodules, and one of the most promising thermal ablation techniques is radiofrequency ablation (RFA). Considering the increasing use of thyroid RFA, some scientific societies have proposed clinical practice guidelines. We systemically reviewed and compared these guidelines for thyroid RFA to identify a standard treatment strategy that represents the positions of most societies. Methods: We searched the MEDLINE and EMBASE databases for studies with human participants that were published in English between January 1, 2000 and August 2, 2019. Studies containing clinical practice guidelines for the RFA of benign thyroid nodules were included. We extracted data regarding indications, pre- and post-procedural evaluations, treatment techniques, and the need to obtain informed consent. Results: Of the 83 studies found, four studies were included, and one study was added after searching the bibliographies of those articles. The five included studies were guidelines developed by the Korean Society of Thyroid Radiology, a group of experts from Italian scientific societies, the Italian Working Group on Minimally Invasive Treatments of the Thyroid, the United Kingdom's National Institute for Health and Clinical Excellence, and a group of four professional Austrian thyroid associations. Indications, pre- and post-procedural evaluations, and techniques were similar across studies; however, differences in each of these categories were found. Conclusion: While the reviewed guidelines are similar with regard to major categories, international guidelines for the RFA of benign thyroid nodules should be established in the future