Technetium-99m-sestamibi scintimammography has been shown to be a useful diagnostic test in the detection of breast cancer. The purpose of this study was two-fold to: (a) evaluate semiquantitative indices of tracer uptake in lesions and determine if they are helpful in distinguishing benign from malignant breast lesions; and (b) test the reproducibility of these measures of sestamibi uptake in breast images.
Methods: Prone lateral planar imaging was performed on 27 patients after intravenous injection of 20-30 mCi 99mTc-sestamibi. Data were analyzed by creating three regions of interest (ROIs) over designated areas: lesion, normal breast and right chest wall. Lesion-to-normal (L:N) and lesion-to-chest wall (L:CW) ratios were calculated for each patient. Reproducibility was assessed by having two independent observers draw ROIs (interobserver) and one observer draw two independent sets of ROIs (intraobserver).
Results: L:N and L:CW ratios were significantly different for malignant versus benign lesions (p < 0.001 for both ratios). Intraobserver and interobserver reproducibility showed good correlation with r = 0.98 (L:CW ratio).
Conclusion: Semiquantitative analysis of sestamibi breast imaging results in reproducible uptake ratios that may be helpful in objectively interpreting imaging results.