Study Of The Shear Wave Velocities On Thyroid Tissues In Patients With Graves Disease

Objective:To investigate the changes of the shear wave velocities on thyroid tissuesin patients with Graves disease by means of acoustic radiation force impulseimaging teconology.Methods:A total of82subjects who came to our hospital from December2012toDecember2013were divided into two groups: GD group including42cases(11men and31women, aged8-73years, mean (30.2±16.1) years)who werefirst diagnosed as Graves disease; normal control group including40cases (20men and20women,aged9-68years, mean (35.6±13.8) years).The inclusion criteria was as follows: GD group:①patients whodiagnosed as Graves disease for the first time, without any treatment;②without apparent nodule and substantive placeholder lesions by examinationof ultrasound;③FT3,FT4and TSH in line with the diagnostic criteria, orconfirmed by pathology FNAB. Normal control group(correspond to the ageof the GD group); thyroid function was normal (including TT3, TT4, FT3,FT4,TSH, TPOAb, TGAb, ect); echo of thyroid was uniform, no nodules werefound by ultrasonic examination, and with the exception of thyroid relateddiseases.Parameters: The size of thyroid, the echo pattern, blood flow distribution,superior thyroid artery flow velocity (PSV and DSV), blood flow volume,shear wave velocity (SWV), thyroid hormone (TSH).Instrument and methods: Siemens Acoson S2000ultrasound system wasused, adopting9L4multi-functional linear array probe and8MHZ frequency.All patients supined, at the beginning, we used grey-scaled ultrasound toexamine each thyroid gland, observing thyroid size, shape, border, internal echo. After that, we performed VTQ test. In each patient seven elastographicmeasurements were made in the right thyroid lobe and seven times in the leftthyroid lobe, excluded the maximum and the minimum and then calculated theaverage value.Statistical analysis: Using SPSS13.0statistical software to analyzethyroid tissue SWV value of each group. GD group and normal control groupSWV value of thyroid tissue adopted group t test. Single factor analysis ofvariance was applied to analyze the significance of GD groups. Therelationship between SWV and TSH used Spearman correlation analysis.Receiver operating characteristic (ROC) curve was performed to estimate thecapacity of the average thyroid SWV value to predict GD using the area undercurve (AUC),sensitivity, specificity, accuracy, positive predictive value andnegative predictive value. For all analyses, a two-tailed P value of less than0.05indicated statistical significance.Results:1Shear wave elastography1.1GD group of shear wave velocity of the different parts of the thyroid glandtissue were higher than control group in the corresponding position, thedifference was statistically significant(P=0.017,0.001,0.017,0.004,0.020,0.004,0.003, P<0.05).1.2Shear wave velocity of GD group at different parts of the thyroid glandtissue had no statistical significance (P=0.878,0.841,1.000,0.988,1.000,P>0.05).1.3There was no linear correlation between the thyroid average shear wavevelocity of GD group and TSH (P=0.120).2From the ROC curve, the cutoff level of SWV for GD was defined as2.075m/s, the sensitivity, specificity, accuracy, positive predictive value,negative predictive value were73.8%,90.9%,81.7%,88.6%,76.6%,respectively. The AUC was0.855.3Conventional ultrasound patterns3.1There were11men and31women among42GD patients. The number of women were more than men.3.2The volumes of GD group and normal control group were compared byusing two independent samples nonparametric test, the result was statisticallysignificant (P=0.000), that is, the volumes of GD group were greater than thenormal control group.3.3In42cases with GD,23cases were Ⅲ level,16cases were Ⅱ level,3cases were Ⅰ level in the blood flow classification.3.4There was no statistically significant difference between GD group’sthyroid PSV、DSV of left lobe and right lobe(P=0.864, P=0.283). The peakvelocity of GD group was higher than normal thyroid.3.5Thyroid blood flow volume of GD was greater than that of normal thyroid.Conclusion:VTQ elasticity imaging technology can evaluate thyroid hardnessquantitatively, shear wave velocity of thyroid tissue can be regarded as areference index of clinical diagnosis of GD, which provide a new method toidentify diffuse thyroid lesions.