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