Retention Index of Tc-99m MIBI Thyroid Scintigraphy, Ultrasonography, and Fine-Needle Aspiration Cytology
in the Assessment of Thyroid Nodule
Ivana D. Mulyanto1, Basuki Hidayat1, Dimyati Achmad2, A. Hussein S.Kartamihardja1, Johan S. Masjhur1
Department of Nuclear Medicine1, Department of Oncological Surgery2 Universitas Padjadjaran - Dr. Hasan Sadikin Hospital
Bandung, Indonesia
BACKGROUND
*Revised American Thyroid Association Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer.Thyroid 2009;19:1167 – 8
Palpable 5% woman and 1% man
US 19 – 67%
PREVALENCE
BACKGROUND
1. Revised American Thyroid Association Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer.Thyroid 2009;19:1167–82. Schlumberger M., Pacini F. Thyroid tumor 3th ed. Thyroid Nodule. Paris 2006:13–14
Thyroid nodule
Thyroid cancer: 5 – 15%
Benign lesion: 85– 95%
BACKGROUND
• Size, echogenicity, shape, margin, echostructure, calcification
• Operator dependent
• I-123, I-131, Tc-99m pertechnetate
• Cold nodule: 5-15% malignant
• FNAC 15-30% indeterminate result
Non invasive preoperative diagnostic modalities
Tc-99m-hexakis-2-methoxyisobuthylisonitrile (Tc-
99m MIBI)
Negative potential membrane
HIGH UPTAKE & RETENTION
Malignant cell
High number and activity of mitochondria
High number and activity of
mitochondria
Malignant thyroid nodule
•Rodrigues M, Chehne F, Kalinowska W, Berghammer P, Zielinski C, Sinzinger H. Uptake of 99mTc-MIBI and 99mTc-Tetrofosmin into malignant versus nonmalignant breast cell lines. J Nucl Med 2000; 41: 1495-9•Carew JS, Huang P. Mitochondrial defects in cancer. Mol Cancer 2002; 1: 9
OBJECTIVE
This prospective study was designed to assess the significance of Tc-99m MIBI thyroid scintigraphy using retention index(RI)
parameter, ultrasound(US), and fine-needle aspiration cytology(FNAC) in differetiating
benign from malignant thyroid nodule.
MATERIAL & METHOD
Patients with palpable single thyroid nodule
US
Tc-99m MIBI thyroid scintigraphy
FNAC
Surgery
Inclusion criteria:• cold nodule on Tc-99m pertechnetate thyroid scan;• normal serum TSH and thyroid hormone level
Kang score ≤2 benignKang score >2 malignant
Benign : coloid goitre, thyroiditisIndeterminate : follicular neoplasmMalignant : papillary thyroid ca
Lobectomy, isthmolobectomy, or total thyroidectomy
Dual phase acquisition with semiquantitative analysis
RESULT
RESULT
RI of Tc-99m MIBIHistopathological finding
p valueMalignant Benign
Mean(SD) 1.04(0.50) 0.58(0.17) 0.0015
RESULT
Cut-off point: >0.58 Sensitivity : 87.5% Specificity : 70.6%PPV : 58.3% NPV : 92.3%Accuracy : 76% (95%CI: 47.3-99.7; LR: 2.98)
US Histopathological finding Total p value
Malignant BenignKang score >2 7 (87.5%) 8 (47.1%) 15 Kang score ≤2 1 (12.5%) 9 (52.9%) 10
Total 8 17 25 0.065
RESULT
Sensitivity 87.5%; specificity 52.9%; PPV 46.7%; NPV 90%; accuracy 64%
RESULT
FNAC Histopathological finding Total p value
Malignant Benign
Malignant 5 0 5
Indeterminate 2 4 6
Benign 1 13 14
Total 8 17 25 0.001
Sensitivity 62.5%; specificity 76.5%; PPV 55.5%; NPV 81.3%; accuracy 72%Indeterminate results (n=6):
- 2 (33.3%) malignant (follicular thyroid ca)- 4 (66.6%) jinak (follicular adenoma)
Tc-99m MIBI RI diagnosed 5 of 6 subjects (83.3%) with indeterminate result
RESULT
Tc-99m MIBI Thyroid Scintigraphy US FNACSensitivity 87.5% 87.5% 62.5%Specificity 70.6% 52.9% 76.5%
NPV 92.3% 90% 81.3%PPV 58.3% 46.7% 55.5%
Accuracy 76% 64% 72%Kappa Index 0.51 0.38 0.33
Discussion One subject with Tc-99m MIBI RI
of 0.39 showed malignant histopathological finding.
Five subjects with Tc-99m MIBI RI of 0.68 – 0.93 showed benign
histopathological finding.
• Size• Vascular supply • Proliferation rate ?
CONCLUSION
RI of Tc-99m MIBI thyroid scintigraphy may be useful in the assessment of thyroid nodule, for it has high negative predictive value and agreement compared to histopathological result.
Thank You