Solitary Thyroid Nodules - Validity of Ultrasonography, Fine Needle Aspiration Cytology and Sestamibi in Detecting Thyroid Malignancies - A Cross-Sectional Study in Kerala

Author(s): Shilpa Suresh1, Riju R. Menon2, Pradeep Jacob3, C. Gopalakrishnan Nair4

The diagnosis of thyroid malignancies continues to remain a challenge, due to lack
of specificity with various modalities, and intrinsic variability with clinical
examination. Although histopathological diagnosis is confirmatory, there is a need
for pre-surgical assessment and confirmation, which will prove to be useful in
decision making regarding the course of management. The present study was
carried out to evaluate the validity of various modalities for detection of thyroid
This cross-sectional study was carried out among 40 patients who presented to
the outpatient clinic with thyroid nodules. All the participants were evaluated by
ultrasound, fine needle aspiration cytology (FNAC) and sestamibi scintigraphy. All
the participants were taken up for surgery and the resected specimen was sent
for histopathology for confirmatory diagnosis.
Ultrasound and FNAC detected malignancy in 25 % of the participants, while
sestamibi scintigraphy detected malignancy in 30 % of the participants. Based on
histopathology, the gold standard confirmatory test, malignancy was detected in
35 % of the participants. It was observed that the sensitivity was highest for FNAC
(75 %) followed by TC methoxyisobutylisonitrile (TC MIBI) (50 %). Specificity was
highest for FNAC (95 %) followed by ultrasound (88 %) (P < 0.0001).
FNAC has the highest sensitivity and specificity while ultrasound and sestamibi
have comparable specificity. There is a high probability of malignancy when the
delayed image in sestamibi scintigraphy shows retention. MIBI may prove to be
useful in differentiating benign and malignant follicular lesions.