Double phase Tc-99m MIBI scintimammography with dedicated breast specific gamma camera in the evaluation of breast masses: Quantitative analysis

Objectives To evaluate diagnostic performances of quantitative analysis of double phase Tc-99m MIBI imaging with dedicated breast specific gamma camera for breast masses.

Methods Early(10 min) and delayed(40 min) scintimammography were performed after injection of 925 MBq of Tc-99m MIBI in the patients with breast masses. Lesion to background ratio(L/B) and washout rate were calculated and compared to the results of histopathology.

Results Twenty eight lesions were malignant(22 IDC, 3 DCIS, 1 adenoid cystic carcinoma, 1 mucinous adenoca, 1 ILC), and 61 were benign. Size of malignant breast mass(27.2±13.9 mm) was larger than the benign lesions(14.4±6.4 mm). L/B ratio was higher in the malignant lesions(early 3.61±1.29, delay 3.56±1.25) than in benign lesions (early 2.65±0.77, delay 2.40±0.64). However, no statistical differences between early and delayed L/B ratio on both benign and malignant lesions. Washout rate showed that more retention of tracer in the malignant lesions (0.009±0.09) than in the benign lesions (0.06±0.12).

Conclusions Dedicated high-resolution scintimammography with double phase quantitative analysis were very useful in characterizing breast masses