The present study is an observational study conducted on 200consecutive patients from December 2014 to December 2016 in the Department ofRadio-diagnosis, Pathology and Surgery at Jawaharlal Nehru Medical College andHospital, Aligarh Muslim University, Aligarh UP India. The patients presentingto the surgery out-patient department for neck swelling were initiallyclinically evaluated for thyroid swelling. They were referred to the radiologydepartment and underwent ultrasound of the thyroid.
Color and power Dopplerwere used as and when necessary. This study was approved by institutional ethicsand research advisory committee, Faculty of Medicine, JNMCH, AMU. TheStatistical software namely SPSS 22.
0, MedCalc 12.7 were used for the analysisof the data.INCLUSION CRITERIA:· Patients with suspected thyroid nodules · All the age group· Both sexesEXCLUSION CRITERIA:Patients with diffuse thyroid disease were excluded from thestudy.SONOGRAPHICEVALUATIONAllUS scans and power Doppler US Examinations of the thyroid gland were performed using Samsung Medison Sonoace X8 with a linear-array transducer (5-12 MHz) that providesenough penetration (about5 cm depth) and excellent resolution (0.7-1 mm) using anoptimized gain.
Power Doppler examinations were performed by using the standardequipment settings for thyroid ultrasound. The patient was examined in supine position withthe neck hyperextended (a pillow may be placed below the shoulders to achieveneck hyperextension). US features of all of the thyroid nodules were prospectivelyrecorded for clinical use according to the internal component, echogenicity,margins, calcifications, shape & vascularity. Using the modifiedRuss classification, each nodule was classified into a TIRADS category (I, II,III, IVA, IVB and V) based on the US features. Based on the results of a previousstudy, a solid component, hypoechogenicity, marked hypoechogenicity,microlobulated or irregular margins, microcalcifications, and ataller-than-wide shape were counted as suspicious US features (REFERENCE)US-GUIDED FNAB/FNAC AND REFERENCESTANDARDUS-guidedfine needle aspiration cytology (FNAC) were performed by the same radiologistswho performed the initial scans for each thyroid nodule without administrationof local anaesthesia. 3-4 Smears were made for each nodule using 23-gaugeneedle attached to a 2 ml disposable plastic syringe. Materials obtained fromaspiration biopsy were used to prepare smears, immediately placed in 95% ethylalcohol & sent to the Department of pathology for papanicolaou staining.Cytopathologists of the hospital interpreted the smears.
Reporting ofthyroid cytology, fine needle aspiration cytology results will be classified asbenign, indeterminate, suspicious for papillary thyroid carcinoma, malignant,or inadequate.13 Also those patients who haveundergone surgery their histopathological reports were also collected. We comparedUltrasonography diagnoses with cytopathology and surgical histopathologicalreports.DATA AND STATISTICAL ANALYSISSensitivity, specificity, positive predictive value (PPV) and negativepredictive value (NPV) was calculated for each of the suspicious US featuresthat are highly suggestive of malignancy as described in USG section REFRENCES Kwak JY et al.
5 and Kim E-Y et al. The risk of malignancy for each categoryof TIRADS classification was determined. The threshold for statisticalsignificance was set at 0.05. All statistical analysis was performed using thestatistical software SPSS 22.
0 (SPSS Inc, Chicago, USA).RESULTSA total of 200patients were evaluated in our study. FNAC reports showed indeterminate resultin ten cases and there was inconclusive report owing to inadequatesampling/technical error in nine patients.
Thus 19 patients were excluded fromthe study. Out of 181 patients, eleven nodules (6.07 % ) were malignant andrest 170 (93.
9 % ) nodules were benign. In our study above mentioned ultrasoundcharacteristics Table- 1 were included so as to further group them intoTIRADS.1.
Majority of the nodules were predominantly solidin its internal content. 100 % of the malignant nodules were predominantlysolid and majority of the predominantly cystic nature of the nodules werebenign in nature.2. Hypoechogenicity was noted in 63.6 % of themalignant nodule with the sensitivity and specificity of 63.6% and 89.4%respectively which shows that hypoechogenicity was more specifically associatedwith the malignancy.3.
Anechoic, isoechoic and hyperechogenicity natureof the nodules were a consistent feature of benign nodules.4. Specificity of taller than wide shape in thedetection of malignant lesions was very high (98.
8%). In our study irregularshape of the nodule also showed high specificity (98.8 %) for malignancy.Majority of the nodules with oval to round shape were benign (90%).5. Sensitivity and specificity of spiculated marginin the detection of malignant nodule was 55.
5% and 92.7% respectively. Thisshows that spiculated margin is highly specific feature of a malignant nodule.6. Microcalcification was more specificallyassociated with the malignant nodule and seen in the 27.3% cases withsensitivity and specificity of 27.3% and 98.8% respectively.
This shows thatmicrocalcification is another significant diagnostic ultrasonography feature todifferentiate between benign and malignant nodules. And macrocalcification wasnoted only in benign nodules (100 %).Among the ultrasound characteristicsas shown in Table 2, malignant nodules revealed highest specificity forspiculated margin (100 %), followed by microcalcification (98.8 %) & tallerthan wide (98.8 %) as a malignant ultrasonography characteristics. However, thesensitivity was low for all these features.
Highest sensitivity was noted forpredominantly solid nature (100 %) for malignant nodules. Highest positivepredictive value was noted for spiculated margins (100 %).Among the benign USG characteristicsTable 3 , anechoicnature showed the highest specificity followed by macrocalcification (87.6%),hyperechoic (86.5%) and predominantly cystic (76.5 %) nature.In our study, TIRADS grading was donebased on previously described different ultrasound characteristics used todifferentiate benign and malignant nodules.
Out of total 181 patients, maximum number ofthe patients belonged to TIRADS grade 3 (n = 147) ( Benign = 145 and Malignant= 2 ). TIRADS grade IVA and IVB had 7 and 8 patients respectively. Out of 181 nodules,the positive predictive value was 100 % for grade V malignant nodules Table 4 followed by 75%for grade IV B malignant nodules. There was significant difference between IV Aand IV B malignant nodules with IV A having very low risk for malignancy and IVB having significantly high risk for malignancy.
DISCUSSION USG is now increasingly being used to evaluatethyroid diseases to characterize the morphology of the lesion and suggest apathologic diagnosis. The role has expanded to assess the local extent of thelesions, any nodal involvement and guide FNAC wherever indicated. In thepresent study, 200 patients who were clinically suspected to have thyroidnodules were evaluated by USG and graded according to the Russ’s modifiedTIRADS algorithm and FNAC showed indeterminate result in 10 cases and there wasinconclusive report owing to inadequate sampling/technical error in 9 patients.Thus 19 patients were excluded from the study. A female preponderance was notedin patients with thyroid nodules in all age groups. The overall sex ratio wasM:F = 1:6.3. Of the 181 cases of nodular thyroid disease examined 11 proved tobe malignant and the rest were benign.
In our study 27.3 % of malignant thyroid noduleswere of taller than wide shape. The sensitivity and specificity of taller thanwide shape in the detection of malignant lesions were 27.3% and 98.8%respectively. This shows that the taller than wide shape has a high specificityfor malignancy.
In our study irregular shape of the nodule also shows high specificity(98.8 %). Result of current study is in consistent with the study conducted by Moonet al 2008.Diana et al 2011 described that therisk of malignancy was more with solid nodule. In our study 100 % of themalignant thyroid nodules and 76.5% of the benign nodules were predominantlysolid in consistency and majority of the benign nodules were of predominantly cysticin nature.
In the present study, there was one case of intacystic papillarycarcinoma which had cystic internal consistency with large internal solidcomponent. FNAC was taken from the solid area and diagnosed to be a malignantintracystic papillary neoplasm Case 9…FIG. Hypoechogenicity was noticed in63.6 % of the malignant nodule with the sensitivity and specificity of 63.
6%and 89.4% respectively whereas hypoechogenicity seen in 10.6 % cases of benign nodules.Hypoechogenicity was more specifically associated with the malignancy. Moonet al and Diana et al in their study reported that the frequency ofhypoechogenicity was significantly different between benign and malignantnodules and hypoechogenicity was highly specific for diagnosing malignantnodules.
Out of the eleven proven malignant nodules, five (45.5%)had smooth margin followed by ill defined margin which was seen in four cases (36.4%). However, sensitivity and specificity of spiculated margin in the detectionof malignant nodule was 55.5% and 92.7% respectively. This shows thatspiculated margin is highly specific feature of a malignant nodule.
Moon etal reported similar result with sensitivity of 48.3% and specificity of91.8% for speculated margin in the detection of malignant nodule.
In the current study three cases (27.3 %) ofmalignant nodules showed microcalcification whereas (1.2 %) benign nodulesshowed microcalcification. Microcalcification was more specifically associatedwith the malignant nodule and seen in the 27.3% cases with sensitivity andspecificity of 27.3% and 98.
8% respectively. Moon et al 2008 reported that themicrocalcifications have a high positive predictive value (41.8%–94.2%) but alow sensitivity (26.1%–59.1%) in the detection of malignant nodule. In ourstudy the positive predictive value of microcalcification for the diagnosingmalignant nodule was 60.0 % and macrocalcification showed high negative predictivevalue of 93.
1 %.Kim et al.10 previouslyreported the same result that hypoechogenicity, marked hypoechogenicity, andtaller than wide shape were the ultrasound features which best predicted thechance of malignancy in thyroid nodules. These features were considered to be suspiciousfor malignancy in study conducted by Kwak et al, Nam-Goongetal 11, Salmaslioglu A et al 12 and Tae HJ et al 1Some investigators suggest a combination of thesefeatures is known to provide better diagnostic accuracy than a single featurealone.
However, considerable variation in the Sensitivity and specificity ofthe US findings for malignant thyroid nodules are reported. Factors that mayaffect the findings reported in previous studies include the use of differentUS equipment, operator’s experience and the different US criteria foridentifying a malignancy. In addition to unavoidable inter-observer variabilityduring the US examination. Since 2009 multiple studies have been conductedon TIRADS and its reliability in the evaluation of malignant and benign thyroidnodules and to identify whether it had a good diagnostic performance of thyroidlesions.Comparing the diagnostic performance of TIRADS inthe present study with other studies Table 4 (Hovarth et al ,Park et al14,Kwaket al,Kim et al, Moifo et al15, Chandramohan et al16) show that the risk ofmalignancy increases as we advance the grading of TIRADS from grade III tograde V.
The result shows that present study for TIRADS grade II, IV A, IV B& V is correlating with the other studies while present study for TIRADSgrade III is correlating with the study of kwak et al. In our study itwas also noted that there is substantial increase in the risk of malignancy (i.efrom 28.
57 % to 75 %) was noted from TIRADS grade IVA to grade IVB and V. Anylesion with grade IV and V should always be biopsied because the overall riskof malignancy is very high. Conclusion USG is the best diagnostic tool in the assessmentof thyroid nodule. The number of diagnosed non-palpable thyroid nodules isincreasing as a consequence of the widespread use of USG. Among all theclinically palpable lesions, incidence of malignancy is low. So, it becomesvery important to differentiate benign from malignant nodules and to guidefine-needle aspiration cytology of nodules suspected for malignancy.
There are combinationsof USG features that can suggest the possibility of malignancy. TIRADS servesas a convenient classification system which can guide the clinicians to biopsythe TIRADS IV and V nodules, thus helping in better patient management.