Experience in Using Breast Single-Photon Emission Computed Tomography with ^99mTc-MIBI

Objective: evaluation of the results of single-photon emission computed tomography (SPECT) with technetium-99m-methoxyisobutylisonitrile (99m Tc-MIBI ) in women with breast masses according to mammography (MMG) and ultrasound (US) examination in comparison with the results of morphology analysis. Material and methods . SPECT with 99m Tc-MIBI was performed in 11 women aged from 30 to 63 years (median age 40 [33.5; 46.5]) with BI-RADS (Breast Imaging Reporting and Data System) categories 4 or 5 mammary masses according to bilateral MMG and US diagnostics. Two patients underwent repeated SPECT and US to analyze the primary tumor response to neoadjuvant chemotherapy. Results . With a multimodal approach to the diagnosis of breast tumors, including MMG and US, 11 pathological masses were identified. SPECT made it possible to find an additional mass that had not been previously visualized. All 12 masses were subsequently verified morphologically. With benign changes, hyperfixation of 99m Tc-MIBI was not observed. SPECT allowed to assess the accumulation of the radiopharmaceutical in metastatically affected lymph nodes. However, the most sensitive method for detecting the axillary lymph node lesions is US. According to the results of repeated SPECT in 2 patients, no radiopharmaceutical accumulation was noted in mammary gland masses after two courses of neoadjuvant chemotherapy, but according to the histological examination, the tumor response was different: I and IV degrees of pathomorphosis according to G.A. Lavnikova Conclusion. The experience of using mammary SPECT with 99m Tc-MIBI confirms an increase in the accuracy of radiologic diagnosis of newly identified breast cancer, expands the possibilities of examination in cases of ambiguous MMG and US data, as well as the contraindications or patient’s refusal from magnetic resonance imaging.