The value of magnetic resonance relaxation time in staging ovarian endometrial cysts

We evaluated the use of magnetic resonance imaging (MRI) in the pre-operative staging of 15 endometrial cysts. The effect of the iron content on the T1 and T2 relaxation times was assessed in confirmed endometrial cysts employing a 0.15 T MR system and a 200 MHz spectrometer. There was a positive linear correlation (r = 0.93) between the T1 values of the lesions obtained using the MR system (T1) and those of the resected cyst contents obtained using the spectrometer (sp-T1). A similar relationship was found between T2 and sp-T2 (r = 0.87). There was a negative linear relationship between the T1 value and the cyst iron content (r = -0.81), but there was no relationship between the T2 value and the iron content. T1 was 412 +/- 91 ms for Stage II cysts (n = 3), 356 +/- 126 ms for Stage III cysts (n = 3) and 208 +/- 30 ms for Stage IV cysts (n = 9). The T1 value for Stage IV cysts was significantly shorter than that for Stages II and III cysts (p less than 0.05). Thus, the T1 value was useful in distinguishing fresh from old endometrial cysts, suggesting that the MRI T1 relaxation time might be useful for staging ovarian endometrial cysts before surgery.