Diagnostic Accuracy of Quantitative Scintimammography Using Tc-99m Tetrofosmin according to ROC Curve Analysis for Breast Cancer

Abstract

Purpose: Tc-99m Tetrofosmin is a new alternative to Tc99m MIBI for nuclear breast imaging. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the feasibility of Tc-99m Tetrofosmin quantitative scintimammography (SMM) (qSMM) and to compare with previously reported Tc-99m MIBI qSMM data [J Kor Surg 1999;57(5):638-644)]. Methods: Prone anterior, lateral planar and supine SPECT images were taken from 135 cases in 131 female patients (mean ages=44 yr) with breast mass (size≥0.2 cm) after 30mCi intravenous injection of Tc-99m Tetrofosmin. 70 malignant and 65 benign lesions were histologically proven. Three regions of interest (ROIs) were drawn over designated areas: the Lesion (L), the Normal breast opposite the lesion (NL) and the right Chest wall (CW). L/NL and L/CW ratios on both the SPECT and the planar images were analyzed. Results: ROC curve analysis revealed that the planar L/NL ratio and the SPECT L/NL and L/CW ratios had higher diagnostic accuracy for detecting breast cancer than the planar L/CW ratio did (P<0.05). The qSMM (mean), which is an arithmetic mean of the planar L/NL ratio, the SPECT L/NL ratio and the SPECT L/CW ratio, the sensitivity, the specificity, accuracy and area under curve (AUC) were 82.9%, 81.5%, 82.2% and 0.879 respectively. Presence of axillary lymph node metastasis showed a slightly higher qSMM (mean) value (2.79 {n=23} vs 2.75 {n=27} P=0.06). These are comparable with previously reported Tc-99m MIBI qSMM data of 84.4%, 76.6%, 81.0% and 0.847 respectively, and the presence of axillary lymph node metastasis showed a higher qSMM(mean) value (4.09 {n=17} vs 3.09 {n=28}, P=0.06) [J Kor Surg 1999; 57(5):638-644)]. Conclusion: Tc-99m Tetrofosmin qSMM (mean) is a useful and objective method for differentiating malignant from benign breast lesion and has the comparable diagnostic accuracies of Tc-99m MIBI qSMM. (Journal of Korean Breast Cancer Society 2004;7:49-54)