Study Of Ultrasonic Elastography Parameters Applied In The Diagnosis Of Thyroid Nodules

Objective: To investigate the diagnostic value of ultrasonic elastography(UE) forthyroid nodules in order to make clinical effective treatment.Methods:52patients with82nodules were examind on the basis of high-frequencyultrasound (HFU) before surgery. Observed the number, size, borde, shape,anteroposterior to transverse diameter ratio, internal echo, microcalcifications, capsule,haloes, distribution of blood flow and resistence index. Then start to UE mode, theelastogram were analyzed referred to the five-score by the Itoh. Elastic score wasdeveloped by two experienced ultrasound physician to rate the graph classification.Many discussions the score if the experience lack to concensus. To calculate the arearatio by measuring the area of each nodule under the UE and two-dimension gray-scaleultrasonography mode. Analyzed and compared with the sensitivity, specificity,accurary, positive predictive value, negative predictive value of high-frequencyultrasound, UE scoring and the two with pathologic diagnosis as a gold standard.Receiver operating characteristic curve was plotted analyzing the diagnostic value ofelasticity stiffness score and area ratio. In accordance with the focal depth, the thyroidnodules were divided into superficial and deep group. The elastographic diagnosis inthe two groups were respectively compared.Results:(1)High-frequency ultrasound image features of anteroposterior to transverse diameterratio and blood supply between the benign and malignant thyroid nodules weredifferent(P<0.05). Diagnosis in borde, shape, internal echo and microcalcificationsaspects the difference were statistically significant(P<0.01). Diagnosis in haloes andresistence index the difference were not statistically significant(P＞0.05).(2)The sensitivity, specificity, accurary, positive predictive value, negative predictive value of high-frequency ultrasound, UE scoring and the two in diagnosing benign andmalignant thyroid nodules were85.42%,67.65%,78.05%,78.85%,76.67%;86.96%,66.67%,78.05%,76.92%,80.00%;93.88%,81.82%,89.02%,88.46%,90.00%,respectively. The accuracy of the two combined was higher than those ofhigh-frequency ultrasound and UE scoring method compared by the McNemar χ2test(P<0.05).(3)The area ratio of benign thyroid nodules ranged from0.88to1.66(1.29±0.19). Thearea ratio of malignant thyroid nodules ranged from1.30to2.01(1.67±0.22). The arearatio of the benign thyroid nodules was significantly different with those of themalignant ones by the McNemar t test (P<0.01). The area ratio of the malignant thyroidnodules were higher than the benign ones. ROC curves were obtained to assess theperformance of the area ratio. The Az was0.902.1.41was the best cutoff point of thearea ratio for differentiating benign from malignant thyroid nodules. The sensitivity,specificity, accurary, positive predictive value, negative predictive value were92.86%,67.50%,80.49%,75.00%,90.00%. The accuracy of area ratio was not significantlydifferent with those of UE scoring method(P>0.05). The accuracy of area ratio wassignificantly different with those of the two(P<0.05).(4) The accuracy of different depth for UE scoring was not significantly different fordifferenttianting benign and malignant breast lessions (P＞0.05).Conclusion:(1)The diagnosis of thyroid nodules is based on high-frequency ultrasound, but there isa certain overlap on the high-frequency ultrasound image feature in benign andmalignant nodules. Therefore one can rely solely on indicators to be judged. It shouldbe comprehensively analysised when you want to improve the accuracy of diagnostic.(2)Ultrasound elasticity imaging can reflect the hardness of the organization. It canmake up for the deficiency of high-frequency ultrasound and provide more informationfor the diagnosis of benign and malignant thyroid nodules. Combination with UEscoring and high-frequency ultrasound greatly enhanced the accuracy of diagnosis. (3)The area ratio of thyroid nodules can indirectly evaluate the surrounding thyroidtissues of nodules involving the scope and extent. It can be used as another effectivesupplementary measure for differentiating benign and malignant thyroid nodules.1.41was the best cutoff point of the area ratio for differentiating benign and malignantthyroid nodules.(4)The UE scoring are correlative with the hardness of the lesion rather than its sizeand depth at a given range.