TECHNETIUM-99M-SESTAMIBI SCINTIMAMMOGRAPHY FOR THE DETECTION OF BREAST-CARCINOMA - COMPARISON BETWEEN PLANAR AND SPECT IMAGING

The purpose of our study was to compare the results of planar and SPEC T scintimammography for the detection of breast carcinoma. In addition , our goal was to determine whether SPECT reconstructed with filtered backprojection (FBP) or with iterative algorithms (ISA) can improve th e sensitivity and specificity of planar scintimammography (SMM), Metho ds: One hundred thirteen patients with suspicious physical examination s and/or mammography underwent planar lateral and anterior breast imag ing as well as SPECT imaging after injection of Tc-99m-sestamibi. We u sed a blind evaluation, both separately and combined, for planar SMM, ISA-SPECT and FBP-SPECT. Scintigraphic findings were correlated with t he final histopathological diagnoses. Results: The sensitivity of plan ar SMM was 80% with a specificity of 83%. All ISA-SPECT studies were o f diagnostic quality, while FBP-SPECT was considered nondiagnostic in 14 that were excluded for statistical calculation. Sensitivity of ISA- SPECT and FBP-SPECT were 71% and 69%, respectively. Specificity was 70 % for ISA-SPECT and 66% for FBP-SPECT. Combined planar SMM plus ISA-SP ECT sensitivity was 85% (81% for planar SMM plus FBP-SPECT) with a spe cificity of 72%. Three carcinomas indeterminate on planar SMM were cor rectly identified by combined planar SMM plus ISA-SPECT. ISA-SPECT and FBP-SPECT provided additional information to planar SMM with respect to localization of sestamibi uptake, tumor extent, improved diagnostic certainty and detection of axillary nodes in 40 and 14 patients, resp ectively. Conclusion: ISA reconstruction is the preferable approach to SPECT data. Combined with planar SMM, ISA-SPECT can improve sensitivi ty. SPECT is useful in cases of indeterminate and positive planar SMM.