Functional breast imaging with Tc 99m Mibi for detection of primary breast lesion and axillary lymph node metastases

Breast cancer is the most common cancer among women and the second leading cause of death in women after lung cancer. The principle aim is to study the utility of Tc- MIBI scintimammography in evaluation of breast cancer and lymph node metastases.

A total of 36 patients both with breast lumps or/and axillary masses suspected breast cancer on clinical examination and/or at conventional imaging procedures (CIP's) were included in this study. The mean age was 47.13 years, median age 47 and age range 22-77 years. All patients received a 740-1000 MBq bolus IV injection of 99mTc-MIBI preferably in a pedal vein. At 5-10 min post injection planar images were obtained in prone lateral and supine anterior position using dual head gamma camera. MIBI uptake was scored as follows: 1 for normal uptake (compared with contralateral side), 2 for focal low intense uptake (equivocal), 3 for focal high intense uptake (positive). All patients had histopathology for tissue diagnosis.

There were 36 patients who presented with breast lesions (30 palpable, 6 non-palpable) and 8 patients with axillary lump. Scan was found true positive in 24 patients and was true negative in 7 patients with breast lesion. In case of axillary lump, it was true positive in 4 and true negative in 2 patients. Planar scintimammography showed sensitivity of 86%, specificity 88%, PPV 96%, NPV 64% and accuracy of 86% (p<0.01). However sensitivity, specificity, PPV, NPV and accuracy for axially metastasis were 86%, 67%, 80%, 67% and 75% respectively. (P-value <0.01).

It is concluded from the study that SMM has good diagnostic accuracy in the detection of breast cancer specially in palpable lesion and lymph node metastases.