Typical and atypical pelvic MRI characteristics of Mayer-Rokitansky-Küster-Hauser syndrome: a comprehensive analysis of 201 patients.

<bold>Objectives: </bold>To comprehensively evaluate the pelvic magnetic resonance imaging (MRI) findings of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome and summarize the typical and atypical characteristics.<bold>Methods: </bold>A retrospective analysis of 201 consecutive MRKH patients was carried out. Pelvic MRI was reviewed by two experienced gynecological radiologists in consensus. Characteristics including the morphology, signal pattern and volumes of the uterine rudiments, location and volume of the ovaries, and the degree of vaginal dysgenesis were evaluated. Other noted abnormalities were also recorded.<bold>Results: </bold>Morphologically, the majority (95%) of patients displayed bilateral uterine rudiments combined with a fibrous band. The minority of patients showed no (3.5%) or unilateral (1.5%) uterine rudiments. A total of 385 uterine rudiments were detected which showed four types of signal patterns: one-layer differentiation (325, 84.4%), two-layer differentiation (27, 7%), three-layer differentiation without subsequent alteration (23, 6.0%), and three-layer differentiation with hematometra and/or ipsilateral hematosalpinx (10, 2.6%). The median volumes of these four types of uterine rudiments were 2.6 ml (1.69-3.81 ml), 3.19 ml (2.67-4.51 ml), 6.05 ml (3.37-12.44 ml), and 31.97 ml (19.2-38.7 ml), respectively. The mean ovarian volume was 6.49 ± 3.91 ml. Abnormally located ovaries were detected in 63 (31.3%) patients. The distal vagina was discernable in 25.1% of patients.<bold>Conclusion: </bold>MRKH patients typically display bilateral uterine rudiments combined with a fibrous band and normally located ovaries. The uterine rudiments are generally small with only one-layer differentiation, a subset of which might be large and exhibited other atypical presentations, including two- or three-layer differentiation or even hematometra. Abnormally located ovaries are not rare.<bold>Key Points: </bold>• Morphologically, MRKH patients typically displayed bilateral uterine rudiments combined with a fibrous band. • Typically, the uterine rudiments (84.4%) were small and displayed only one-layer differentiation. • About 15.6% of rudiments showed atypical characteristics including two- or three-layer differentiation, even complicated with hematometra or hematosalpinx. [ABSTRACT FROM AUTHOR]