There were 39 solitary adenomas,
2 double adenomas,
3 parathyroid hyperplasias in 43 patients (20 male,
23 females) with age of 41.7 +/- 11.6 years; serum corrected calcium and PTH was 11.12 +/- 1.02 mg/dL and 417.7 +/- 444.1 ng/L respectively; size and weight was 20 +/- 9.74 mm (range of 11 – 48 mm) and 198.9 +/- 255.8 mg (range of 47-1032 mg) respectively.
ARFI elastography was performed on 102 thyroid nodules and surgical histopathology was available for 93 of them (23 males and 70 females).
Out of them 38 were benign thyroid nodules (BTN) and 55 were malignant thyroid nodules (MTN). The size of the thyroid nodule was 36 +/- 15.8 mm (range of 11-72 mm).
Surgical histopathology of lesions included in the study.
Benign thyroid nodules
Malignant thyroid nodules
Adenomatous or nodular hyperplasia
Hurthle cell adenoma
Papillary carcinoma of thyroid
Follicular variant of papillary carcinoma (FVPTC
Medullary carcinoma of thyroid
Shear wave velocity measurements:
The mean SWV of parathyroid lesion was 1.6 +/-0.78 m/s (range of 0.61 to 4.8 m/s).
The mean SWV of benign and malignant thyroid nodules was 2.11 +/- 0.8 m/s (range of 0.8 to 4.8 m/s) and 4.3 +/- 2.71 m/s (1.05 to 8.4 m/s) respectively.
This difference was statistically significant,
p < 0.05.
Figure 2 shows the box plot comparing the SWV (m/s) of parathyroid and thyroid nodules.
Majority (n = 36,
78.3%) of parathyroid lesions had an elasticity index of 2,
8 lesions had an EI of one and two lesions had an EI of three. None of them showed an elasticity index of four.
Majority (89.1%) of malignant nodules had elasticity score of 3 (n = 36) and 4 (n=13).
But majority (79%) of BTN had an EI of one (n = 18) or two (n = 12).
Eight BTN showed an EI of three.
There was significant difference in the EI of parathyroid and thyroid lesions (chi square = 51.6,
There was a characteristic speckled pattern on VTI in most (n=41,
91.1%) of the parathyroid lesions.
Figure 3 and 4 shows an example of the speckled appearance of parathyroid lesions in two different patients with right inferior parathyroid adenomas.
However this appearance was seen in only few (n=9,
9.1%) thyroid nodules.
This difference was quiet significant,
Chi square = 87.04,
The nine thyroid lesions which had this appearance in part of the lesion was due to artifacts caused by foci of cystic degeneration (n=6) and micro calcification (n=3).
ROC analysis showed an area under the curve (95% CI) of 0.901 (0.848-0.967) (Figure 5),
0.797 (0.72-0.875) and 0.724 (0.641 – 0.808) respectively for speckled appearance on VTI,
VTQ and elasticity score respectively to differentiate parathyroid and thyroid lesion.
NPV and accuracy of speckled appearance of parathyroid lesions as a sign to differentiate parathyroid and thyroid lesions was 91.1 %,
95.45% and 90.5% respectively.
The SWV cut off which offers the best diagnostic performance for parathyroid is 1.72 m/s with a sensitivity of 75.3% and specificity of 71.1%.
Tc99m Sestamibi scintigraphy:
Tc99m Sestamibi scitigraphy and SPECT was discordant with the surgical findings in 11/43 (25.5%) patients.
ultrasound correctly localized the parathyroid lesion in 9/11 patients.
Ultrasound was discordant with the surgical findings in 2 patients (4.6 %),
one due to missed double adenoma and other due to concomitant thyroid nodule,
the later was false positive on Tc99m sestamibi scintigraphy as well.