The All the age group · Both sexes EXCLUSION

The present study is an observational study conducted on 200
consecutive patients from December 2014 to December 2016 in the Department of
Radio-diagnosis, Pathology and Surgery at Jawaharlal Nehru Medical College and
Hospital, Aligarh Muslim University, Aligarh UP India. The patients presenting
to the surgery out-patient department for neck swelling were initially
clinically evaluated for thyroid swelling. They were referred to the radiology
department and underwent ultrasound of the thyroid. Color and power Doppler
were used as and when necessary. This study was approved by institutional ethics
and research advisory committee, Faculty of Medicine, JNMCH, AMU. The
Statistical software namely SPSS 22.0, MedCalc 12.7 were used for the analysis
of the data.

INCLUSION CRITERIA:

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·        
Patients with suspected thyroid nodules

·        
All the age group

·        
Both sexes

EXCLUSION CRITERIA:

Patients with diffuse thyroid disease were excluded from the
study.

SONOGRAPHIC
EVALUATION

All
US 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 provides
enough penetration (about5 cm depth) and excellent resolution (0.7-1 mm) using an
optimized gain. Power Doppler examinations were performed by using the standard
equipment settings for thyroid ultrasound. The patient was examined in supine position with
the neck hyperextended (a pillow may be placed below the shoulders to achieve
neck hyperextension). US features of all of the thyroid nodules were prospectively
recorded for clinical use according to the internal component, echogenicity,
margins, calcifications, shape & vascularity. Using the modified
Russ 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 previous
study, a solid component, hypoechogenicity, marked hypoechogenicity,
microlobulated or irregular margins, microcalcifications, and a
taller-than-wide shape were counted as suspicious US features (REFERENCE)

US-GUIDED FNAB/FNAC AND REFERENCE
STANDARD

US-guided
fine needle aspiration cytology (FNAC) were performed by the same radiologists
who performed the initial scans for each thyroid nodule without administration
of local anaesthesia. 3-4 Smears were made for each nodule using 23-gauge
needle attached to a 2 ml disposable plastic syringe. Materials obtained from
aspiration biopsy were used to prepare smears, immediately placed in 95% ethyl
alcohol & sent to the Department of pathology for papanicolaou staining.
Cytopathologists of the hospital interpreted the smears. Reporting of
thyroid cytology, fine needle aspiration cytology results will be classified as
benign, indeterminate, suspicious for papillary thyroid carcinoma, malignant,
or inadequate.13 Also those patients who have
undergone surgery their histopathological reports were also collected.

We compared
Ultrasonography diagnoses with cytopathology and surgical histopathological
reports.

DATA AND STATISTICAL ANALYSIS
Sensitivity, specificity, positive predictive value (PPV) and negative
predictive value (NPV) was calculated for each of the suspicious US features
that 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 category
of TIRADS classification was determined. The threshold for statistical
significance was set at 0.05. All statistical analysis was performed using the
statistical software SPSS 22.0 (SPSS Inc, Chicago, USA).

RESULTS

A total of 200
patients were evaluated in our study. FNAC reports showed indeterminate result
in ten cases and there was inconclusive report owing to inadequate
sampling/technical error in nine patients. Thus 19 patients were excluded from
the study. Out of 181 patients, eleven nodules (6.07 % ) were malignant and
rest 170 (93.9 % ) nodules were benign. In our study above mentioned ultrasound
characteristics Table- 1 were included so as to further group them into
TIRADS.

1.      
Majority of the nodules were predominantly solid
in its internal content. 100 % of the malignant nodules were predominantly
solid and majority of the predominantly cystic nature of the nodules were
benign in nature.

2.      
Hypoechogenicity was noted in 63.6 % of the
malignant nodule with the sensitivity and specificity of 63.6% and 89.4%
respectively which shows that hypoechogenicity was more specifically associated
with the malignancy.

3.      
Anechoic, isoechoic and hyperechogenicity nature
of the nodules were a consistent feature of benign nodules.

4.      
Specificity of taller than wide shape in the
detection of malignant lesions was very high (98.8%). In our study irregular
shape 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 margin
in the detection of malignant nodule was 55.5% and 92.7% respectively. This
shows that spiculated margin is highly specific feature of a malignant nodule.

6.      
Microcalcification was more specifically
associated with the malignant nodule and seen in the 27.3% cases with
sensitivity and specificity of 27.3% and 98.8% respectively. This shows that
microcalcification is another significant diagnostic ultrasonography feature to
differentiate between benign and malignant nodules. And macrocalcification was
noted only in benign nodules (100 %).

Among the ultrasound characteristics
as shown in Table 2, malignant nodules revealed highest specificity for
spiculated margin (100 %), followed by microcalcification (98.8 %) & taller
than wide (98.8 %) as a malignant ultrasonography characteristics. However, the
sensitivity was low for all these features. Highest sensitivity was noted for
predominantly solid nature (100 %) for malignant nodules. Highest positive
predictive value was noted for spiculated margins (100 %).

Among the benign USG characteristics
Table 3 , anechoic
nature showed the highest specificity followed by macrocalcification (87.6%),
hyperechoic (86.5%) and predominantly cystic (76.5 %) nature.

In our study, TIRADS grading was done
based on previously described different ultrasound characteristics used to
differentiate benign and malignant nodules. Out of total 181 patients, maximum number of
the 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 A
and IV B malignant nodules with IV A having very low risk for malignancy and IV
B having significantly high risk for malignancy.

 

DISCUSSION

 

USG is now increasingly being used to evaluate
thyroid diseases to characterize the morphology of the lesion and suggest a
pathologic diagnosis. The role has expanded to assess the local extent of the
lesions, any nodal involvement and guide FNAC wherever indicated. In the
present study, 200 patients who were clinically suspected to have thyroid
nodules were evaluated by USG and graded according to the Russ’s modified
TIRADS algorithm and FNAC showed indeterminate result in 10 cases and there was
inconclusive report owing to inadequate sampling/technical error in 9 patients.
Thus 19 patients were excluded from the study. A female preponderance was noted
in patients with thyroid nodules in all age groups. The overall sex ratio was
M:F = 1:6.3. Of the 181 cases of nodular thyroid disease examined 11 proved to
be malignant and the rest were benign.

 

In our study 27.3 % of malignant thyroid nodules
were of taller than wide shape. The sensitivity and specificity of taller than
wide 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 specificity
for 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 Moon
et al 2008.

Diana et al 2011 described that the
risk of malignancy was more with solid nodule. In our study 100 % of the
malignant thyroid nodules and 76.5% of the benign nodules were predominantly
solid in consistency and majority of the benign nodules were of predominantly cystic
in nature. In the present study, there was one case of intacystic papillary
carcinoma which had cystic internal consistency with large internal solid
component. FNAC was taken from the solid area and diagnosed to be a malignant
intracystic papillary neoplasm Case 9…FIG. Hypoechogenicity was noticed in
63.6 % 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. Moon
et al and Diana et al in their study reported that the frequency of
hypoechogenicity was significantly different between benign and malignant
nodules and hypoechogenicity was highly specific for diagnosing malignant
nodules.

 

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 detection
of malignant nodule was 55.5% and 92.7% respectively. This shows that
spiculated margin is highly specific feature of a malignant nodule. Moon et
al reported similar result with sensitivity of 48.3% and specificity of
91.8% for speculated margin in the detection of malignant nodule.

In the current study three cases (27.3 %) of
malignant nodules showed microcalcification whereas (1.2 %) benign nodules
showed microcalcification. Microcalcification was more specifically associated
with the malignant nodule and seen in the 27.3% cases with sensitivity and
specificity of 27.3% and 98.8% respectively. Moon et al 2008 reported that the
microcalcifications have a high positive predictive value (41.8%–94.2%) but a
low sensitivity (26.1%–59.1%) in the detection of malignant nodule. In our
study the positive predictive value of microcalcification for the diagnosing
malignant nodule was 60.0 % and macrocalcification showed high negative predictive
value of 93.1 %.

Kim et al.10 previously
reported the same result that hypoechogenicity, marked hypoechogenicity, and
taller than wide shape were the ultrasound features which best predicted the
chance of malignancy in thyroid nodules. These features were considered to be suspicious
for malignancy in study conducted by Kwak et al, Nam-Goonget
al 11, Salmaslioglu A et al 12 and Tae HJ et al 1

Some investigators suggest a combination of these
features is known to provide better diagnostic accuracy than a single feature
alone. However, considerable variation in the Sensitivity and specificity of
the US findings for malignant thyroid nodules are reported. Factors that may
affect the findings reported in previous studies include the use of different
US equipment, operator’s experience and the different US criteria for
identifying a malignancy. In addition to unavoidable inter-observer variability
during the US examination. Since 2009 multiple studies have been conducted
on TIRADS and its reliability in the evaluation of malignant and benign thyroid
nodules and to identify whether it had a good diagnostic performance of thyroid
lesions.

Comparing the diagnostic performance of TIRADS in
the present study with other studies Table 4 (Hovarth et al ,Park et al14,Kwak
et al,Kim et al, Moifo et al15, Chandramohan et al16) show that the risk of
malignancy increases as we advance the grading of TIRADS from grade III to
grade 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 TIRADS
grade III is correlating with the study of kwak et al. In our study it
was also noted that there is substantial increase in the risk of malignancy (i.e
from 28.57 % to 75 %) was noted from TIRADS grade IVA to grade IVB and V. Any
lesion with grade IV and V should always be biopsied because the overall risk
of malignancy is very high.

 

Conclusion

 

USG is the best diagnostic tool in the assessment
of thyroid nodule. The number of diagnosed non-palpable thyroid nodules is
increasing as a consequence of the widespread use of USG. Among all the
clinically palpable lesions, incidence of malignancy is low. So, it becomes
very important to differentiate benign from malignant nodules and to guide
fine-needle aspiration cytology of nodules suspected for malignancy. There are combinations
of USG features that can suggest the possibility of malignancy. TIRADS serves
as a convenient classification system which can guide the clinicians to biopsy
the TIRADS IV and V nodules, thus helping in better patient management.