OBJECTIVE: The objective of this study was to assess the usefulness of Gadolinium contrast enhancement in differentiating adenomyomas from leiomyomas and normal myometrium.DESIGN: We identified all pelvic MR scans performed at Washington University 2003-2007 fulfilling the following criteria: use of Gadolinium contrast and concomitant presence of at least one adenomyoma, at least one leiomyoma, and at least one area of normal myometrium, as independently reported by two senior radiologists.MATERIALS AND METHODS: On all pelvic MR scans that met inclusion criteria, the signal intensity (SI) of myometrial, adenomyomatous and leiomyomatous tissue were measured before and after Gadolinium enhancement. All signal intensities were calculated relative to the pre-Gadolinium signal intensity. The heterogeneity of each tissue was then graded by 2 independent radiologists on a scale of 1-4, in reference to myometrium. Mean heterogeneity scores for each group were calculated and compared with unpaired t-tests.RESULTS: Myometrial tissue enhanced by factors of 2.1, 3.6 and 3.6 after Gadolinium administration at sequence 1, 2 and 3 (95% Confidence Interval < 0.27). There was significantly less Gadolinium enhancement in adenomyomas, which enhanced by 1.4, 2.4 and 2.5 (95% CI < 0.21). A wide variation was observed in the Gadolinium enhancement of leiomyomas, which enhanced by 1.9, 2.8 and 3.2 (95% CI > 0.53).Table 1Vascularity of adenomyomas and leiomyomas relative to myometrium on contrast MR scanTimepointPre-GadoliniumPost 1Post 2Post 3Normal myometrium12.0573.6223.646Adenomyoma0.9411.3622.3942.492Leiomyoma0.9931.8772.8473.19095% Confidence Interval: <0.27 for Normal myometrium; <0.21 for Adenomyoma; >0.53 for Leiomyoma. Open table in a new tab CONCLUSIONS: Whereas leiomyomas revealed a wide variation in their enhancement patterns, adenomyomas demonstrated less enhancement relative to normal myometrium on Gadolinium enhanced MR imaging. Adenomyomas are more homogenous and enhance less than leiomyomas. These findings may be important in differentiating adenomyomas from leiomyomas and thereby assist in pre-operative planning. OBJECTIVE: The objective of this study was to assess the usefulness of Gadolinium contrast enhancement in differentiating adenomyomas from leiomyomas and normal myometrium. DESIGN: We identified all pelvic MR scans performed at Washington University 2003-2007 fulfilling the following criteria: use of Gadolinium contrast and concomitant presence of at least one adenomyoma, at least one leiomyoma, and at least one area of normal myometrium, as independently reported by two senior radiologists. MATERIALS AND METHODS: On all pelvic MR scans that met inclusion criteria, the signal intensity (SI) of myometrial, adenomyomatous and leiomyomatous tissue were measured before and after Gadolinium enhancement. All signal intensities were calculated relative to the pre-Gadolinium signal intensity. The heterogeneity of each tissue was then graded by 2 independent radiologists on a scale of 1-4, in reference to myometrium. Mean heterogeneity scores for each group were calculated and compared with unpaired t-tests. RESULTS: Myometrial tissue enhanced by factors of 2.1, 3.6 and 3.6 after Gadolinium administration at sequence 1, 2 and 3 (95% Confidence Interval < 0.27). There was significantly less Gadolinium enhancement in adenomyomas, which enhanced by 1.4, 2.4 and 2.5 (95% CI < 0.21). A wide variation was observed in the Gadolinium enhancement of leiomyomas, which enhanced by 1.9, 2.8 and 3.2 (95% CI > 0.53). 95% Confidence Interval: <0.27 for Normal myometrium; <0.21 for Adenomyoma; >0.53 for Leiomyoma. CONCLUSIONS: Whereas leiomyomas revealed a wide variation in their enhancement patterns, adenomyomas demonstrated less enhancement relative to normal myometrium on Gadolinium enhanced MR imaging. Adenomyomas are more homogenous and enhance less than leiomyomas. These findings may be important in differentiating adenomyomas from leiomyomas and thereby assist in pre-operative planning.