| Object: Acoustic radiation force impulse (ARFI) elastography is aquantitative technique to measure of tissue stiffness. The study was aimed toassess the value of ARFI for identification benign and malignant thyroidnodules.Methods: This research included93patients of118nodules who werecarried out thyroidectomy, aged from20to80years old, average (51.2+12.8) years old, involved18men and75women. The nodules size rangefrom0.5to8.0cm, average of (2.12±1.25)cm. Single nodules in35patientsand multiple nodules in58people in the research.Siemens S2000color doppler ultrasonic diagnostic apparatus were usedfor application, which equipped with virtual touch tissue imaging, VTI andvirtual touch tissue quantification, VTQ software,9L4multi-functional lineararray probe was used, the frequency range of7-9MHz. All patients tooksupine, the neck pad and the head back, fully exposed the neck, routineultrasound examination and ARFI measurement were performed respectively.The total nodules were evaluated using traditional ultrasoundexamination and color doppler ultrasound, the parameters include the size ofthyroid nodule, position， aspect ratio, boundary, internal echo andcalcification features, single or multiple. The color doppler ultrasonic wasapplied for the graphical blood flow of the nodules and small artery bloodflow spectrum within the nodules, the resistance of nodules and the bloodflow distribution of nodules were classified.The qualitative and quantitative measurement of thyroid nodules andthe normal thyroid tissue around the nodules were assessed using VirtualTouch Impulse (VTI) imaging and Virtual Touch Quantification,(VTQ) imaging, then went to VTQ measurement model, told patients stop swallow,probes shoud be perpendicular to organization, and lightly touch with theneck for it’s weight, any external force must be avoided, images werecollected and saved, the parameters, such as shear wave velocity, SWV valuewere recorded. some nodules showed SWV values for XXX m/s thatdetermines the amount of value should be combined with VTI image. VTIexpressed in gray-scale images, according to the hardness of soft to hard,respectively, according to the lesion area showed that the proportion of blackand white color will be VTI images from white to black. five times should bemeasured in each nodule and the normal thyroid tissue around, the averagewas calculated. Parameters with mean±standard deviation were adoptedSPSS17.0software and to compare with the pathology results using T test,when P <0.05was statistically significant, the ROC curve was depictedaccording to the results of surgical pathology, diagnostic criteria, fordifferentiating benign from malignancy in thyroid solid nodules of thecritical value, according to the area under the curve (AUC) concluded itssensitivity, specificity, accuracy, positive predictive value and negativepredictive value.Results:1Pathology results: Total of89nodules were approved benign by pathology,of which56nodular were goiter,15nodules were adenomatous hyperplasia,10nodules were thyroid adenoma,5nodular goiters were toxic goiter,1nodule was thyroiditis of wood samples,1nodule was inflammatory cellsinfiltration,1nodule was eosinophilic cell tumor; Total of29nodules wereapproved malignant by pathology, among them18thyroid nodules werepapillary carcinoma,5nodules were little papillary carcinoma,2noduleswere follicular carcinoma,2nodules were undifferentiated carcinoma,1noudle was poorly differentiated adenocarcinoma,1noudle was follicularadenocarcinoma.2Routine ultrasound results:2.1According to the criteria of conventional ultrasound diagnosis for benign and malignant nodules, malignant were diagnosed in25nodules, in which8nodules were false diagnosed:1nodules in the pathology confirmed forthyroid adenoma,1for thyroiditis of wood samples,6for nodular goiterassociated with calcification,17malignant nodules were corrected diagnosed;93benign nodules were diagnosed with the criteria of ultrasound, in which13nodules were false diagnosed:12nodules were malignant nodules,1wasinflammatory cells infiltration,80benign nodules were corrected diagnosed，the sensitivity, specificity and accuracy were56.7%,90.9%,82.2%respectively, positive predictive value and negative predictive value were68.0%,86.0%respectively.2.2According to the classification standard as type0-4for the flow of nodules.Among benign nodules:1.1%(1/89) nodules had a Blood flow of type0,6.7%(6/89) nodules had a Blood flow of type1,44.9%(40/89) nodules had a Bloodflow of type2,32.6%(29/89) nodules had a Blood flow of type3,14.6%(13/89) nodules had a Blood flow of type4.Among malignant nodules,0%(0/29) nodules had a Blood flow of type0,51.7%(15/29) nodules had a Bloodflow of type1,3.4%(1/29) nodules had a Blood flow of type2,31.0%(9/29)nodules had a Blood flow of type3,13.8%(4/29) nodules had a Blood flow oftype4.2.3According to the criteria of the resistance index (RI) which higher than0.7for malignant nodules, lower than0.7for benign nodules. For the benignnodules,8nodules for RI higher than0.7,67nodules for RI lower than0.7,14nodules had not been drawn out blood flow frequency spectrum; For themalignant nodules,17nodules for RI higher than0.7,9nodules for RI lowerthan0.7,3nodules had not been drawn out blood flow frequency spectrum.The sensitivity, specificity and accuracy were68.0%,88.0%,83.1%respectively, positive predictive value and negative predictive value were65.3%,89.3%respectively.3The acoustic radiation force impulse imaging results:3.1The mean SWV of the benign nodule and the adjacent thyroid tissue were(2.07±0.8) m/s,(2.20±0.54) m/s. The mean SWV of the malignant nodule and the adjacent thyroid tissue were (4.39±2.78) m/s,(2.19±0.55) m/s.3.2The statistical analyses were carried out using SPSS17.0software， thedifferences between the mean SWV of benign and malignant nodule and theadjacent thyroid tissue were compared with independent T test. Analysis ofvariance was used to compare whether there were significant differences in theSWV among different pathologic types. There were significant differences inSWV between benign and malignant groups (t=4.44, p=0.000); but therewere no significant differences between the groups of the adjacent thyroidtissue.3.3ROC curve analyses showed that the AUC for the SWV was0.879indifferentiating benign from malignant thyroid nodules. The best cutoff pointswere2.57m/s for SWV, the sensitivity, specificity and accuracy were82.7%,82.1%,90.0%respectively, positive predictive value and negative predictivevalue were77.4%,94.2%respectively.Conclusion:This study shows that ARFI technology providesquantitative and qualitative information about the tissue stiffness, whichprovides a new useful tool for identification of benign and malignant thyroidnodules. swv value of2.57m/s may be a diagnostic point, it can be moreaccurately in identification of benign and malignant thyroid nodules. SoARFI technology in the differential diagnosis of benign and malignantthyroid nodules have important clinical value, it is a very important auxiliaryexamination method for clinical doctors. But acoustic radiation force impulseimaging is still at the initial stage of application and has certain limitation inclinical practice, it remains to be further exploration and research. With thedeepening of the research ARFI technology and ultrasonic doctor diagnosisand treatment technology unceasing enhancement, ARFI technology willprovide more accurate for the clinical diagnosis and differential diagnosis inthe future. |
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