The taller-than-wide sign indicates that the anteroposterior dimension-to-transverse dimension ratio (AP/T ratio) is higher than 1. The aim of the present study was to reconfirm the accuracy of the taller-than-wide sign for diagnosing malignant thyroid nodules by ultrasonography in multicenter collaborative research, and investigate differences according to tumor sizes, histological types, and the influence of the tilt and orientation of the probe. At 6 registered institutes, 2,032 thyroid nodules were successively operated on and diagnosed pathologically. The accuracy of the taller-than-wide sign for diagnosing malignant tumors by ultrasonography was retrospectively analyzed across all nodules as well as in analyses separately stratified by tumor size and histology. The influence of the tilt and orientation of the probe was also assessed. The taller-than-wide sign showed high specificity for diagnosing malignancy in all nodules tested. It also showed high specificity regardless of the tumor size. When tumors were analyzed by histological types, the AP/T ratio of papillary carcinoma was significantly higher than that of benign nodules, whereas no significant difference was observed between follicular carcinoma and benign nodules. The specificity of longitudinal sections was significantly higher, while the AUC of longitudinal sections was significantly larger than those of transverse sections. The AP/T ratio obtained when the probe was tilted was not significantly different from that when it was straight. The present results support the usefulness of the taller-than-wide sign for diagnosing malignant tumors regardless of size, but not follicular carcinoma. The influence of the tilt and orientation of the probe was negligible.

高过宽标志表明前后尺寸与横向尺寸比（AP / T比）高于1。本研究的目的是再次确认高过宽标志的诊断准确性多中心协作研究超声检查恶性甲状腺结节，并根据肿瘤大小、组织学类型以及探头倾斜和方向的影响调查差异。在6个注册机构，先后对2032个甲状腺结节进行了手术和病理诊断。回顾性分析了所有结节以及按肿瘤大小和组织学分层的分析中，通过超声检查诊断恶性肿瘤的高过宽标志的准确性。还评估了探头倾斜和方向的影响。在所有测试的结节中，高过宽标志显示出对诊断恶性肿瘤的高度特异性。无论肿瘤大小如何，它也显示出高特异性。按组织学类型分析肿瘤时，乳头状癌的AP/T比值显着高于良性结节，而滤泡状癌与良性结节之间无显着差异。纵切面特异性显着高于横切面，纵切面AUC显着大于横切面。探针倾斜时获得的 AP/T 比与直线时的 AP/T 比没有显着差异。目前的结果支持高过宽标志用于诊断各种大小的恶性肿瘤，但不支持滤泡癌。