1. 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

2. BACKGROUND US  19 – 67% Palpable  5% woman and 1% man P R E V A L N
*Revised American Thyroid Association Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer.Thyroid 2009;19:1167 – 8

3. BACKGROUND Thyroid nodule Thyroid cancer: Benign lesion: 85– 95%
5 – 15%
Benign lesion: 85– 95%
Revised American Thyroid Association Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer.Thyroid 2009;19:1167–8
Schlumberger M., Pacini F. Thyroid tumor 3th ed. Thyroid Nodule. Paris 2006:13–14

4. Non invasive preoperative diagnostic modalities
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

5. Tc-99m-hexakis-2-methoxyisobuthylisonitrile (Tc-99m MIBI)
Negative potential membrane
HIGH UPTAKE & RETENTION
High number and activity of mitochondria
High number and activity of mitochondria
Malignant thyroid nodule
Malignant cell
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:
Carew JS, Huang P. Mitochondrial defects in cancer. Mol Cancer 2002; 1: 9

6. 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.

7. Material & Method Inclusion criteria:
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  benign
Kang score >2  malignant
Dual phase acquisition with semiquantitative analysis
Benign : coloid goitre, thyroiditis
Indeterminate : follicular neoplasm
Malignant : papillary thyroid ca
Lobectomy, isthmolobectomy, or total thyroidectomy

8. RESULT

9. Histopathological finding
RESULT
RI of Tc-99m MIBI
Histopathological finding
p value
Malignant
Benign
Mean(SD)
1.04(0.50)
0.58(0.17)
0.0015

10. RESULT Cut-off point: >0.58 Sensitivity : 87.5% Specificity : 70.6%
PPV : 58.3%
NPV : 92.3%
Accuracy : 76%
(95%CI: ;
LR: 2.98)

11. Histopathological finding
RESULT US
Histopathological finding
Total
p value
Malignant
Benign
Kang score >2
7 (87.5%)
8 (47.1%) 15
Kang score ≤2
1 (12.5%)
9 (52.9%) 10 8 17 25
0.065
Sensitivity 87.5%; specificity 52.9%; PPV 46.7%; NPV 90%; accuracy 64%

12. Histopathological finding
RESULT
FNAC
Histopathological finding
Total
p value
Malignant
Benign 5
Indeterminate 2 4 6 1 13 14 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

13. Tc-99m MIBI Thyroid Scintigraphy
RESULT
Tc-99m MIBI Thyroid Scintigraphy US
FNAC
Sensitivity
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

14. ? Size Vascular supply Proliferation rate 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 ?

15. 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.

16. Thank You