Detection of Ductal Carcinoma in Situ with Mammography, Breast Specific Gamma Imaging, and Magnetic Resonance Imaging: A Comparative Study1

Rationale and Objectives

To evaluate the sensitivity of high-resolution breast-specific gamma imaging (BSGI) for the detection of ductal carcinoma in situ (DCIS) based on histopathology and to compare the sensitivity of BSGI with mammography and magnetic resonance imaging (MRI) for the detection of DCIS.

Materials and Methods

Twenty women, mean 55 years (range 34–76 years), with 22 biopsy-proven DCIS were retrospectively reviewed. After injection of 25–30 mCi (925–1,110 MBq) technetium 99m-sestamibi, patients had BSGI with a high-resolution, small-field-of-view gamma camera in craniocaudal and mediolateral oblique projections. BSGI studies were prospectively classified according to focal radiotracer uptake using a 1 to 5 scale, as normal 1), with no focal or diffuse uptake; benign 2), with minimal patchy uptake; probably benign 3), with scattered patchy uptake; probably abnormal 4), with mild focal radiotracer uptake; and abnormal 5), with marked focal radiotracer uptake. Imaging findings were compared to findings at biopsy or surgical excision. The sensitivity of BSGI, mammography, and when performed, MRI were determined for the detection of DCIS. Breast MRI was performed on seven patients with eight biopsy-proven foci. The sensitivities were compared using a two-tailed t-test and confidence intervals were determined.

Results

Pathologic tumor size of the DCIS ranged from 2 to 21 mm (mean 9.9 mm). Of 22 cases of biopsy-proven DCIS in 20 women, 91% were detected with BSGI, 82% were detected with mammography, and 88% were detected with magnetic resonance imaging. BSGI had the highest sensitivity for the detection of DCIS, although this small sample size did not demonstrate a statistically significant difference. Two cases of DCIS (9%) were diagnosed only after BSGI demonstrated an occult focus of radiotracer uptake in the contralateral breast, previously undetected by mammography. There were two false-negative BSGI studies

Conclusions

BSGI has higher sensitivity for the detection of DCIS than mammography or MRI and can reliably detect small, subcentimeter lesions.

Key Words: Breast cancer, molecular imaging, breast biopsy, nuclear medicine imaging