Development of a novel breast MRI phantom for quality control.

OBJECTIVE: Many indications for breast MRI exist. MRI screening can identify preinvasive breast cancer in women at high risk and in that regard is superior to mammography and ultrasound. Quality control standards exist for mammography and breast ultra-sound screening with phantoms designed specifically for this purpose. Given the growing importance of breast MRI, we propose the development of a breast MRI phantom for quality control purposes.

MATERIALS AND METHODS: A breast phantom with dual cavities containing water and fat was developed. A resolution plate inside the phantom contains various shapes ranging in size from 1 to 20 mm. Twenty studies of the phantom were performed with a 1.5-T system. STIR, T1-weighted fat-suppressed, and T2-weighted sequences were completed. Relaxation times of water and fat, number of step shapes resolved on STIR and T2-weighted images, number of circles resolved on T2-weighted images, and the diameter of a 20-mm circle on T1-weighted fat-suppressed images were recorded.

RESULTS: On STIR images the TR of fat was 238.70±96.31 ms and of water was 1231.92±399.14 ms. On T2-weighted images the TR of fat was 778.73±62.60 ms and of water was 1737.60±121.63 ms. On STIR images, steps 3 mm and larger were visualized in 95% of instances. On T2-weighted images steps 3 mm and larger were seen in all instances. Measurements of a 20-mm circle were 19±0.3 mm.

CONCLUSION: The proposed breast MRI phantom can be used to obtain reproducible measurements and allows implementation of quality control measures for a modality that is being increasingly used.