| Summary: | 博士 === 國立臺灣大學 === 臨床醫學研究所 === 102 === Thyroid cancer is the most common endocrine malignancy. The incidence is increasing in the past decades. How to improve the detection rate and diagnostic accuracy has become an urgent issue. We proposed the novel computerized methods in this thesis to quantify the ultrasonic features of thyroid cancer. We included two ultrasonic features which were microcalcifications and heterogeneity in this thesis to test whether computerized method could be helpful in diagnosis of thyroid cancer.
The first part was to improve the ultrasonographic detection rates of thyroid cancers with microcalcifications, we proposed to enhance the sensitivity of sonographic calcifications detection and to avoid inter-observer variation by a computerized quantification method in a prospective setting. A total of 256 nodules were included (173 benign, 83 malignant). Among them, the diagnosis of 181 nodules (102 benign, 79 malignant) were verified by surgical pathology. Quantification of cystic components and calcifications was automatically performed by a proprietary program (AmCAD-UT) implemented with methods proposed in this paper. The calcification index (CI) between benign and malignant nodules diagnosed by combined FNA biopsy and surgical pathology results (total number, 256) showed a significant difference (p<0.001, AUC=0.746). Furthermore, we excluded patients without surgical pathology results for further validation, and the CI between benign and malignant nodules confirmed by pathology results (total number, 181) showed a significant difference (p<0.001, AUC=0.763). To learn whether our computer program increased our diagnostic capabilities, we analyzed human investigators and their abilities to detect and evaluate. In this study, calcifications were noted in 48.19% (40 of 83) of malignant thyroid nodules and in 10.98% (19 of 173) of benign nodules. This new computer-aided diagnosis method to evaluate the sonographic calcifications of thyroid nodules is a more sensitive and more objective method. It can provide better sensitivity than conventional methods in the diagnosis of thyroid malignancies containing microcalcifications.
The second part is to test whether the computerized quantification of ultrasonic heterogeneity can aid the diagnosis of thyroid malignancy, we evaluated ultrasonic heterogeneity by an objective and quantitative computerized method in a prospective setting. A total of 400 nodules including 271 benign thyroid nodules and 129 malignant thyroid nodules were evaluated. Quantification of ultrasonic heterogeneity (heterogeneity index, HI) was performed by a proprietary program implemented with methods proposed in this paper. The HI values between benign and malignant nodules, diagnosed by a combination of fine-needle aspiration (FNA) and surgical pathology results, are significantly different (p<0.001, AUC=0.714). Ultrasonic heterogeneity (US-H) of these samples assessed by an experienced clinician could not significantly differentiate between benign and malignant thyroid nodules. However, the nodules with marked heterogeneity of US-H showed higher HI values than that of nodules with homogeneous US-H assessment. These results indicate that using the new computer-aided diagnosis method to evaluate the ultrasonic heterogeneity of thyroid nodules is an objective and quantitative method that is correlated to the conventional US-H assessment but can aid in the diagnosis of thyroid malignancy better.
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