[Magnetic resonance imaging for the evaluation of prostate cancer metastatic to bone]

The response of bone metastatic lesions to endocrine therapy was assessed by repeated magnetic resonance imaging (MRI) and an isotope bone scan after an average period of 7.0 months (2-10 months) in 12 patients with prostate cancer. MRI used both T1-weighted spin echo technique and short TI IR (STIR) sequence. Of 7 patients with hormone-dependent cancer, the bone metastatic lesions resolved or became vague in all patients on STIR image, while in only 4 and 3 on T1-weighted image and bone scan, respectively. Of 5 patients with hormone-refractory cancer, the lesions progressed on both MRI and bone scan in all patients except one who had initially had diffusely metastatic lesions of systemic bone. The results indicate that STIR image of MRI is helpful for the therapeutic evaluation of bone lesions.