Purpose or Case Report: Intraabdominal cystic lesions are relatively common prenatal diagnoses. Determining its etiology and diagnosis can be challenging on prenatal imaging. Fetal MR is a helpful imaging modality that can provide additional anatomic and physiologic information. The purpose of this study is to evaluate MR imaging findings of fetal intraabdominal cystic lesions with correlation with postnatal imaging and outcome.
Methods & Materials: Following IRB approval a review of the fetal MRI database from 2010-2016 was performed to identify cases of fetal intraabdominal cystic lesions. Exclusion criteria: lack of postnatal follow-up. Fetal MR images were reviewed, as well as pertinent postnatal imaging, laboratory values and relevant surgical/pathologic data.
Results: Of the 55 fetal MRIs identified, 26 met inclusion criteria. Of these, 2 (8%) showed resolution of the cystic lesions on postnatal imaging. The majority of the evaluated lesions were either renal (7/26 or 27%) or intestinal (6/26 or 23%) in origin (Table 1). Additional prenatal diagnoses included sacrococcygeal teratoma 4/26 (15%), suprarenal mass 2/26(8%), torsed ovary 1/26(3%) and hepatobiliary abnormalities 2/26(8%). One presented with a mesenteric lymphatic malformation and one had cloacal malformation with hydrocolpos. T1W sequences obtained in 22/24 cases were scored for added value in making final diagnosis (i.e. detected meconium in meconium pseudocysts, blood products in ovarian cysts, simple fluid signal in lymphatic malformation); T1W images showed added value and increased confidence in diagnosis in all 22/22 cases. Of the 26 MR prenatal diagnoses, only one was corrected postnatally (pt with prenatal diagnosis of choledochal cyst shown to represent an ectopic gallbladder on postnatal imaging).
Conclusions: We show that fetal intraabdominal cystic lesions are predominantly of renal and intestinal origin. T1W sequences afford the added physiologic information which can result in a more accurate final diagnosis; thereby, improving prenatal counseling and post-natal care.