The value of early and double phase 99Tcm-sestamibi scintimammography in the diagnosis of breast cancer.

The aim of this study was to assess the additional value of early and double phase scintimammography (SMM) with 99Tcm-sestamibi in the detection of breast cancer following initial evaluation by palpation and mammography. Altogether, 322 women with breast lesions evaluated prospectively by palpation, fine-needle aspiration and mammography were assigned a malignancy risk according to the results. Scintimammography was performed in all patients in the prone breast dependent position. Immediate and delayed views were obtained. Acquisition of immediate tracer uptake was termed 'early phase' SMM, whereas a combination of both immediate and delayed phase images was termed 'double phase' SMM. All patients underwent breast biopsy. Both early phase and double phase SMM detected eight of nine tumours in the low-risk group (88.8% sensitivity). In the uncertain cases (moderate-risk group), early phase SMM detected all malignant tumours, but double phase SMM missed one (92.3% sensitivity). In the high-risk group, early phase SMM missed two breast cancers (94.6% sensitivity) and double phase SMM missed four (89.2% sensitivity). Overall, early phase SMM had a sensitivity of 94.9% and a specificity of 80.2% in detecting breast cancer, whereas double phase SMM had a sensitivity of 89.8% and a specificity of 94.3%. Both methods had 100% sensitivity for tumours larger than 1 cm. In conclusion, SMM detected additional breast cancers following an initial evaluation by palpation, fine-needle aspiration and mammography. Our results suggest that double phase SMM is more specific than early phase SMM, although early phase SMM is more sensitive. Whether the interpretation of SMM results should rely on both early and delayed images, or early images alone, should be based on the relative risk of malignancy of the breast lesion as estimated by the initial evaluation.

Double-phase 99mTc-sestamibi scintimammography and trans-scan in diagnosing breast cancer.

UNLABELLED: The goal of our study was to assess the value of both scintimammography with 99mTc-sestamibi (SMM) and trans-scan (T-scan) in detecting breast cancer. METHODS: A total of 121 women were evaluated by palpation, mammography, SMM and T-scan. SMM was performed in the prone, breast dependent position. Immediate and delayed views (double-phase) were obtained. T-scan is a new breast imaging method that maps noninvasively the distribution of tissue electrical impedance and capacitance. RESULTS: SMM had 88.9% sensitivity, 88.4% specificity and 88.4% accuracy in detecting breast cancer. SMM had 100% sensitivity in detecting breast tumors >1 cm and only 66% sensitivity in detecting tumors <1 cm. T-scan had 72.2% sensitivity and 67% specificity in detecting breast cancer. It detected one more breast cancer than SMM, at the expense of 27 additional false-positive results. CONCLUSION: Double-phase SMM was sensitive and specific in detecting breast cancer. This method may reduce the rate of negative breast biopsies in tumors >1 cm. T-scan was only moderately accurate in detecting breast cancer. Its addition to SMM did not improve significantly the rate of breast cancer detection. However, because of its complete noninvasiveness, large-scale applicability and low cost, T-scan deserves further refining.