Tc-99m-MIBI Scintimammography; SPECT versus Planar Imaging

Abstract

Planar imaging missed 10 malignant lesions while SPECT missed only 4. Ten benign lesions showed uptake of MIBI on planar imaging while 11 showed uptake on SPECT. Cumulative scores for normal and benign groups did not show any significant difference between planar and SPECT imaging. The malignant group showed significant increase in score for SPECT. Specificity, false negative fraction and positive predictive value for planar imaging were 85.7%, 14.3% and 87.5%. These values did not show any significant difference for SPECT (84.5%, 15.5% and 87.4% respectively). Sensitivity, false negative fraction and negative predictive value for planar imaging (87.5%, 12.5% and 85.7%) was significantly different (p < 0.005) than SPECT (95%, 5% and 93.7% respectively). MIBI SPECT scintimammography improves the sensitivity, false negative fraction and negative predictive value of the planar imaging. In the absence of MIBI uptake on SPECT imaging, malignancy can be ruled out with great confidence, while only uptake should be further evaluated.