Key Clinical MessageA rare case of fetal small intestinal volvulus was diagnosed prenatally using MRI, with characteristic black-and-white and coffee-bean signs. Early diagnosis led to timely surgical intervention and favorable outcome.Case DescriptionA 35-year-old Japanese woman presented with decreased fetal movement at 33 weeks. Ultrasound revealed fetal ascites and dilated intestinal tract. Fetal MRI demonstrated characteristic findings: low T2 signal in dilated intestines (Fig1A, “black-and-white sign”) and adjacent thickened oval loops suggesting torsion (Fig1B, “coffee-bean sign”). Emergency cesarean section was performed. Laparotomy of the baby confirmed twisted necrotic small intestine(Fig2). Segmental resection was performed, and the postoperative course was favorable.AnswerDiagnosis: Fetal small intestinal volvulusIntrauterine diagnosis of fetal small intestinal volvulus is increasing due to the recognition of the disease and the improvement of diagnostic techniques, although it is a rare disease1). Ultrasound is the main diagnostic tool, but not many cases show specific findings for small bowel torsion, such as the whirlpool sign, and it is not easy to distinguish it from gastrointestinal atresia without torsion. However, when small bowel torsion occurs in utero, the prognosis may be poor and forced delivery may be required, so an accurate diagnosis is important. In recent years, MRI has been used for the diagnosis of various fetal diseases, and as the technology has advanced and the imaging time has shortened, the accuracy of diagnosis has also improved. There are still few reports of the use of MRI in cases of fetal small intestinal volvulus, but in addition to the whirlpool sign and coffee-bean sign seen in ultrasound examinations, the black and white sign, which reflects ischemic changes in the intestinal tract, has also been reported2). In this case, the White and black sign and Coffee been sign, which are characteristic of small intestinal volvulus, were shown.Author ContributionsMiyu Nakamura: primary author, case management, and manuscript preparation; Hiroshi Sato: manuscript preparation, prenatal diagnosis and imaging interpretation; Kazuyo Kakui: case supervision and critical review. All authors reviewed and approved the final manuscript.Figure LegendsFigure 1A. Fetal MRI (T2-weighted image) shows low signal intensity within the dilated small intestine (arrow), in contrast to adjacent normal bowel (“black-and-white sign”).Figure 1B. The twisted bowel loop (arrowhead) appears oval-shaped with wall thickening—resembling a “coffee-bean sign.”Figure 2. Postnatal laparotomy shows twisted and discolored small intestine with segmental perforation.References1. Shen AW, et al. Prenatal imaging features and perinatal outcomes of fetal volvulus-A literature review. Prenat Diagn. 2022;42(2):192–200.2. Kou C, et al. Prenatal diagnosis of midgut volvulus by fetal MRI: a retrospective study. Front Pediatr. 2024;12:1442866.