Adenomyosis of the Uterus: Recognition of a Characteristic Enhancement Pattern on Contrast-enhanced Dynamic MRI

ABSTRACT

PURPOSE: To analyze the enhancement patterns of adenomyosis and evaluate the usefulness of dynamic MR imaging in detecting adenomyosis. MATERIALS AND METHODS: Dynamic MR imaging finding in 46 women with adenomyosis were analyzed retrospectively. Dynamic MR imaging was obtained in each patient. Fifteen consecutive FLASH images were obtained before, immediately after and 15, 30, 45, 90 second and 5 minute after bolus injection of Gd-DOTA. Signal intensities of adenomyosis and outer myometrium and standard deviations of image noise were measured using an electronic cursor. Contrast-to-noise ratio (C/N) of the lesion to outer myometrium were calculated as follows ; (signal intensity of outer myometrium-signal intensity of adenomyosis)/(standard deviation) of noise signal intensity. RESULTS: The mean signal intensity of adenomyosis was higher than surrounding outer myometrium before and immediately after contrast injection. On 15, 30, 45, 90 second, and 5 minute after injection the signal intensity of adenomyosis was lower than that of surrounding outer myometrium (p < 0.05). The mean C/N values between adenomyosis and surrounding myometrium on precontrast scan, immediate postcontrast, and 15, 30, 45, 90 second and 5 minute delayed images were 3.20, 5.03, 6.14, 6.87, 7.13, 7.78, 38.59, respectively. On T2-weighted images, the mean C/N value between adenomyosis and surrounding myometrium was 16.7. Mean C/N value between adenomyosis and surrounding myometrium on delayed images was significantly higher than those of other dynamic & T2-weighted images(p<0.05). CONCLUSION: Dynamic MR imaging is very useful in the evaluation of the enhancement pattern and especially in detection of adenomyosis because the mean C/N value between adenomyosis and surrounding myometrium on delayed images are higher than that of T2-weighted images.