Magnetic resonance relaxation time in evaluating the cyst fluid characteristics of endometrioma.

To determine whether the cyst fluid characteristics of endometrioma can be evaluated by magnetic resonance imaging (MRI), 36 endometriomas obtained from 24 patients (age range 21-43 years; mean 34 years) were studied. MRI was performed < 2 weeks before laparoscopy or laparotomy. Comparative studies of the density and concentration of iron in the endometrioma and the signal intensity (SI) of MRI [calculated relaxation time T1 value, calculated relaxation time T2 value, signal intensity on a T1-weighted image (T1SI) and on a T2-weighted image (T2SI) of the cyst; T1SI/signal intensity of the gluteus maximus muscle (MSI), and T2SI/MSI of the cyst] were performed. The density of the cyst fluid and its iron concentration were found to be directly proportional. There was a significant relationship between the concentration of iron and the T2SI, T2SI/MI and calculated T2 values. In particular, the concentration of iron and the ration of T2SI/ MSI were inversely proportional. Therefore, T2SI/MSI reflected the concentration of iron in endometriomas without recourse to measurement of the calculated T2 value, which suggests that the MRI and T2 signal intensity may be useful for evaluating the cyst fluid characteristics of endometriomas.