The clinical value of dual-phase 99Tcm-MIBI SPECT in diagnosis of breast lesions

Objective: 99Tcm-methoxyisobutylisonitfile (MIBI) had been widely reported for breast cancer imaging. However, most of the reports used to be static imaging. The aim of this study was to validate the clinical value of dual-phase 99Tcm-MIBI SPECT in diagnosis of breast lesions. Methods: In all, 119 subjects were included. Twenty-six were normal and 93 had breast lesions. All underwent dual-phase 99Tcm-MIBI SPECT and the imaging device Was self-designed. Tumors to non-tumor radioactivity ratios (T/NT) were calculated at early (5 min) and delayed (180 min) phases. Moreover, the validity of the breast lesions among all patients was based on the results from histopathology. Results: Malignant lesions had the highest uptake of MIBI, followed by benign lesions and normal in both early and delayed phases. No statistical differences were noted between the T/NT at early and delayed phases in normal breasts and malignant tumors (1.09± 0.18 vs 1.08±0.19, t=1.443, P>0.05; 5.00±4.34 vs 6.79±11.94, t=-0.884, P>0.05). Interestingly, significant difference was noted between the T/NT at early and delayed phases in benign tumors (2.08±2.85 vs 1.69±3.05, t=2.814, P<0.05). The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of dual-phase 99Tcm-MIBI SPECT in diagnosis of breast lesions were 97.1%, 79.3%, 86.0%, 73.9% and 97.9%, respectively. The pooled diagnostic coincidence ratio was 86.0%. The diagnostic accuracy was 97.1% in malignant tumors, and 79.3% in begin lesions. If the detect- ability of dual-phase 99Tcm-MIBI SPECT was considered with the tumor size, the sensitivity was 5/6 for tumor diameter of < 2 cm and was 100% (29/29) for those ≥2 cm. Conclusion: This self-design device was optimal to detect breast tumor with 99Tcm-MIBI, especially combined with a dual-phase study. (authors)