99MTechnetium-sestamibi scintimammography in non-palpable breast lesions found on screening X-ray mammography

The use of single-photon emission computed tomography-computed tomography in detecting multiple metastatic lymph nodes in patients with breast cancer

AIM

The aim of the present study was to determine the accuracy of single-photon emission computed tomography-computed tomography (SPECT-CT) with technetium-99m-sestamibi (Tc-MIBI) for detecting multiple (>2 nodes) axillary lymph node involvement in patients with breast cancer (BC).

PATIENTS AND METHODS

A total of 184 women with BC were examined. Clinically, axillary lymph nodes were classified as N0 in all cases. Patients underwent SPECT-CT breast and axillary region imaging 10-15 min after a 740 mBq intravenous injection of Tc-MIBI. SPECT-CT data were then verified by definitive histopathological examination (sentinel-node biopsy and/or axillary lymph node dissection were used as reference standard). Diagnostic values of different CT and SPECT signs of multiple (>2) lymph node involvement were evaluated.

RESULTS

Histological examination of excised lymph nodes showed metastatic involvement in 62 (33.7%) out of 184 patients. In fact, 25 (13.6%) patients had more than two lymph node involvements. In another 37 (20.1%) cases the metastasis was revealed in one or two sentinel lymph nodes only. The main SPECT-CT criteria of multiple (>2) lymph node involvement were as follows: the maximum size of the primary tumor (>20 mm), lymph node dimensions (>12 mm along the long axis and >10 mm along the short axis), nodal cortical thickness (>4 mm), round shape, solid structure, quantity of identified abnormal lymph nodes (>1), and intensity of tracer uptake. The developed integrated model offers the possibility to exclude multiple lymph node metastasis (>2) in BC patients with a probability of 99%.

CONCLUSION

This single-center study showed that in patients with BC, a combination of functional and anatomical data that were obtained by using SPECT-CT with Tc-MIBI can significantly improve detectability of multiple (>2) axillary metastases.

Incidence of deep vein thrombosis in patients undergoing breast reconstruction with autologous tissue transfer

Background Breast reconstruction is associated with multiple risk factors for venous thromboembolism. However, the incidence of deep vein thrombosis in patients undergoing breast reconstruction is uncertain. Objective The aim of this study was to prospectively evaluate the incidence of deep vein thrombosis in patients undergoing breast reconstruction using autologous tissue transfer and to identify potential risk factors for deep vein thrombosis. Methods Thirty-five patients undergoing breast reconstruction were enrolled. We measured patients' preoperative characteristics including age, body mass index (kg/m²), and risk factors for deep vein thrombosis. The preoperative diameter of each venous segment in the deep veins was measured using duplex ultrasound. All patients received intermittent pneumatic pump and elastic compression stockings for postoperative thromboprophylaxis. Results Among the 35 patients evaluated, 11 (31.4%) were found to have deep vein thrombosis postoperatively, and one patient was found to have pulmonary embolism postoperatively. All instances of deep vein thrombosis developed in the calf and were asymptomatic. Ten of 11 patients underwent free flap transfer, and the remaining one patient received a latissimus dorsi pedicled flap. Deep vein thrombosis incidence did not significantly differ between patients with a free flap or pedicled flap (P = 0.13). Documented risk factors for deep vein thrombosis demonstrated no significant differences between patients with and without deep vein thrombosis. The diameter of the common femoral vein was significantly larger in patients who developed postoperative deep vein thrombosis than in those who did not ( P < 0.05). Conclusions The morbidity of deep vein thrombosis in patients who underwent breast reconstruction using autologous tissue transfer was relatively high. Since only the diameter of the common femoral vein was predictive of developing postoperative deep vein thrombosis, postoperative pharmacological thromboprophylaxis should be considered for all patients undergoing breast reconstruction regardless of operative procedure.

Mono- and dicationic Re(I)/(99m)Tc(I) tricarbonyl complexes for the targeting of energized mitochondria

The enhanced negative mitochondrial membrane potential of tumor cells can increase the cell accumulation of triphenylphosphonium (TPP) derivatives, which prompted us to investigate TPP-containing Re(I)/(99m)Tc organometallic compounds as probes for in vivo targeting of energized mitochondria. Novel compounds (Re1-Re4/Tc1-Tc4) were obtained with bifunctional chelators of the pyrazole-diamine (N,N,N-donors) and pyrazole-aminocarboxylic (N,N,O-donors) type, functionalized with TPP pharmacophores that have been introduced at the central amine of the chelators using different spacers. In this way, dicationic (Re1-Re2, Tc1-Tc2) and monocationic (Re3-Re4, Tc3-Tc4) complexes with variable lipophilicity were synthesized. The (99m)Tc complexes (Tc1-Tc4) are highly stable under physiological conditions and their chemical identification was done by HPLC comparison with the Re congeners (Re1-Re4), which were fully characterized by common analytical techniques (electrospray ionization mass spectrometry (ESI-MS), IR, multinuclear NMR). The in vitro biological evaluation of Tc1-Tc4 was performed in a panel of human tumor cell lines (PC-3, MCF-7 and H69), including cell lines overexpressing P-glycoprotein (MCF-7/MDR1 and H69/Lx4), and in isolated mitochondria. All the tested complexes showed a low to moderate cellular and mitochondrial uptake and did not undergo significant P-glycoprotein (Pgp)-mediated efflux processes. In particular, the dication Tc2 and the monocation Tc4 presented the highest cellular and mitochondrial uptake. Their cellular uptake was shown to depend on the mitochondrial (Δψm) and plasma membrane (Δψp) potentials. Altogether, the biological properties of these compounds suggest that they might be relevant for the design of radioactive metalloprobes for in vivo targeting of mitochondria.

99mTc-thymine scintigraphy may be a promising method in the diagnosis of breast cancer

OBJECTIVE

Mammography has been established as the gold standard for the detection of breast cancer, and imaging techniques such as ultrasonography, magnetic resonance imaging, scintigraphy and positron emission tomography may be useful to improve its sensitivity and specificity. The objective of this study with breast scintigraphy was to evaluate the uptake of 99mTc-thymine in mammary lesions.

METHODS

A total of 45 patients were included in this study. Thirty-three patients (73%) were subjected to surgery or percutaneous biopsy, providing histopathological data. The other 12 patients who remained under surveillance received clinical examinations and biannual mammography with a normal follow-up of at least three years, the data from which were used for comparison with the scintimammography results.

RESULTS

The majority of patients (64.4%) had clinically impalpable lesions with a mammogram diagnosis of microcalcifications, impalpable nodules, or focal asymmetry. Of the studied lesions, 87% were smaller or equal to 20 mm in diameter, and 22% had malignant histopathological findings. Scintigraphy with 99mTc-thymine had a sensitivity of 70%, a specificity of 85.7%, positive and negative predictive values of 58.3% and 90.9%, respectively, and an accuracy of 82.2%.

CONCLUSIONS

The results of this study are consistent with those previously reported by other authors. The good specificity and high negative predictive value of this technique and the absence of uptake in the heart indicate that it may be a promising complementary method in clinical practice and that it may contribute to reducing unnecessary benign biopsies.

An X-Ray computed tomography/positron emission tomography system designed specifically for breast imaging

Mammography has served the population of women who are at-risk for breast cancer well over the past 30 years. While mammography has undergone a number of changes as digital detector technology has advanced, other modalities such as computed tomography have experienced technological sophistication over this same time frame as well. The advent of large field of view flat panel detector systems enable the development of breast CT and several other niche CT applications, which rely on cone beam geometry. The breast, it turns out, is well suited to cone beam CT imaging because the lack of bones reduces artifacts, and the natural tapering of the breast anteriorly reduces the x-ray path lengths through the breast at large cone angle, reducing cone beam artifacts as well. We are in the process of designing a third prototype system which will enable the use of breast CT for image guided interventional procedures. This system will have several copies fabricated so that several breast CT scanners can be used in a multi-institutional clinical trial to better understand the role that this technology can bring to breast imaging.