Comparison of diffusion-weighted imaging findings in brain metastases of different origin.

Our purpose was to estimate apparent diffusion coefficient (ADC) values from brain metastases (BMs). Our patient sample included 159 patients with 948 BMs. Magnetic resonance imaging was obtained with a 1.5-T device. For diffusion-weighted imaging, a multislice single-shot echo-planar imaging sequence was used (b values of 0, 500, and 1000 s/mm(2)). The mean ADC value of BMs was 0.98 ± 0.32 × 10(-3) mm(2) s(-1). A total of 72.8% of BM lesions showed ADC values under 0.90 × 10(-3) mm(2) s(-1). Small-cell lung cancer had the lowest ADC values (0.86 ± 0.27) in comparison to BMs from non-small-cell lung cancer (1.17 ± 0.49), breast carcinoma (0.97 ± 0.21), and malignant melanoma (0.99 ± 0.36).