The Usefulness of Mammography and Scintimammography in Differential Diagnosis of Breast Tumor / 대한핵의학회잡지

PURPOSE: It is very important to differentiate breast cancer from benign mass. There are many reports to evaluate the differential diagnosis under the several diagnostic tools. We evaluated the usefulness of mammography and Tc-99m MIBI scintimammography in the differential diagnosis of breast mass and correlated with pathologic findings. MATERIALS AND METHODS: This study included 80 patients (age: 24-72, mean: 48.4) who underwent mammography and Tc-99m MIBI scintimammography for breast masses. Scintimammographies (anterior-posterior and lateral projections) were acquired in 10 minutes and 2 hours after intravenous injection of Tc-99m MIBI. Four specialists in diagnostic radiology and nuclear medicine evaluated the findings of breast masses under the mammography and Tc-99m MIBI scintimammography, and calculated the tumor to background (T/B) ratio. The pathologic results were obtained and we statistically analyzed the correlations between pathologic results and imaging findings under the mammography and Tc-99m MIBI scintimammography by chi-square and correlation test. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value of mammography for detection of breast cancer were 87.5%, 56.3%, 75.0%, and 75.0% respectively. 45 cases of 80 patients were suspicious for breast cancer under the Tc-99m MIBI scintimammography. 41 cases of 45 patients were confirmed as breast cancer and the remaining 4 cases were confirmed as benign masses. The sensitivity, specificity, positive predictive value and negative predictive value of Tc-99m MIBI scintimammography for detection of breast cancer were 85.4%, 87.5%, 91.1%, and 80.8% respectively. The sensitivity of scintimammography was lower than that of mammography for detection of breast cancer, however the specificity, positive predictive value, and negative predictive value were higher. In the benign mass, the mean T/B ratio in 10 minutes was 1.409 +/- 0.30, and that in 2 hours was 1.267 +/- 0.42. The maximal T/B ratio of benign mass in 10 minutes was 1.604 +/- 0.42, and that in 2 hours was 1.476 +/- 0.50. In the malignant mass, the mean T/B ratio in 10 minutes was 2.220 +/- 1.07, and that in 2 hours was 1.842 +/- 0.75. The maximal T/B ratio of malignant mass was 2.993 +/- 1.94, and that in 2 hours was 2.480 +/- 1.34. And the T/B ratio under the early and delayed images were meaningful. CONCLUSION: The scintimammography is useful diagnostic tool to differentiate breast cancer from benign mass, although the sensitivity of mammography for detection of breast mass is high. Especially, the use of the T/B ratio is helpful to diagnose breast cancer.

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

BACKGROUND: Technetium-99m sestamibi scintimammography (SMM) has been shown to be a useful diagnostic test in the detection of breast cancer, and the receiver operating characteristic (ROC) curve analysis provides detailed information about the diagnostic test. A ROC curve analysis was performed to evaluate the feasibility of Tc-99m sestamibi quantitative scintimammography (qSMM) for differentiating malignant from benign breast lesions. METHODS: Prone anterior, lateral planar, and supine SPECT imagings were performed on 75 female patients (mean age=43.4 yr) with breast masses (size> or =0.8 cm) after intravenous injection of 30 mCi of Tc-99m sestamibi. 45 malignant and 30 benign lesions were histologically proven. Three regions of interest (ROIs) were drawn over designated areas: lesion (L), normal breast opposite to the lesion (NL), and right chest wall (CW). L/NL and the L/CW ratios on both the SPECT and the planar images were analyzed. RESULTS: ROC curve analysis revealed that planar L/NL ratio and the SPECT L/NL and L/CW ratios provide better diagnostic accuracies for detecting breast cancer than the planar L/CW ratio did (p<0.05). From the qSMM (mean), which was an arithmetic mean of the planar L/NL, ratio the SPECT L/NL ratio and the SPECT L/CW ratio, the sensitivity, the specificity, the positive predictive value, the negative predictive value, and the accuracy were 84%, 77%, 84%, 77%, and 81%, respectively. Presence of axillary lymph-node metastasis showed a higher qSMM (mean) value (4.09 {n=17} vs 3.09 {n=28}, p=0.06). CONCLUSIONS: qSMM (mean) is a useful objective method for differentiating malignant from benign breast lesions.

Tc-99m MIBI scintimammography (SMM) in the evaluation of palpable breast masses.

Radionuclide breast imaging, also called scintimammography (SMM) was performed using Tc-99m MIBI in 37 patients with palpable breast masses. A total of 38 lesions were analyzed. Twenty cases subsequently underwent modified radical mastectomy while the remainder underwent only biopsy or fine needle aspiration for histologic proof. The average size of the masses were 3.03+1.61 x 4.10+2.89 cm in diameter. Twenty-six lesions were malignant and 12 were benign; 23 malignancies showed positive MIBI uptake but three did not. The false negative cases were all invasive ductal carcinomas. Nine benign lesions were true negatives and three were false positives. They were mastitis, foreign-body granuloma and fat necrosis which chronic inflammation. Of 14 cases which histologically proved to have axillary node metastasis, only 7 revealed positive MIBI uptake. The sensitivity and spectively. However, in the detection of axillary node metastasis, the sensitivity was only 50 percent. Thus, Tc-99m MIBI SMM is helpful in the diagnosis of routine mammography. However, the imaging is not accurate enough for the detection of axillary node metastasis. In addition, Tc-99m MIBUI SMM also plays an important role in terms of prognosis and therapeutic planning in patients with breast cancer.