Certain abdominopelvic vascular structures may be compressed by adjacent anatomic structures or may cause compression of adjacent hollow viscera. Such compressions may be asymptomatic; when symptomatic, however, they can lead to a variety of uncommon syndromes in the abdomen and pelvis, including median arcuate ligament syndrome, May-Thurner syndrome, nutcracker syndrome, superior mesenteric artery syndrome, ureteropelvic junction obstruction, ovarian vein syndrome, and other forms of ureteral compression. These syndromes, the pathogenesis of some of which remains controversial, can result in nonspecific symptoms of epigastric or flank pain, weight loss, nausea and vomiting, hematuria, or urinary tract infection. Direct venography or duplex ultrasonography can provide hemodynamic information in cases of vascular compression. However, multidetector computed tomography is particularly useful in that it allows a comprehensive single-study evaluation of the anatomy and resultant morphologic changes. Anatomic findings that can predispose to these syndromes may be encountered in patients who are undergoing imaging for unrelated reasons. However, the diagnosis of these syndromes should not be made on the basis of imaging findings alone. Severely symptomatic patients require treatment, which is generally surgical, although endovascular techniques are increasingly being used to treat venous compressions.

Placenta accreta is abnormal placental adherence or invasion of the myometrium or extrauterine structures. It is increasing in incidence because of increasing number of cesarean sections and is one of the main causes of excessive postpartum hemorrhage. Recognition of this entity is crucial because improved outcomes have been shown when the antenatal diagnosis of placenta accreta is made. Ultrasound is the first-line tool; magnetic resonance imaging (MRI) is complementary. Ultrasound and MRI features and MRI protocols will be reviewed.

Proximal femoral focal deficiency is an extremely rare congenital anomaly with only a few case reports in the literature. This case illustrates one diagnosed by prenatal ultrasound. The diagnosis may be isolated or associated with other abnormalities and syndromes. This report describes the early obstetrical ultrasound diagnosis, its evolution and associated findings throughout pregnancy. To the best of our knowledge, it is the first report associating this diagnosis with sickle cell trait. Another finding in our patient was a concomitant intrauterine growth restriction that we attribute to placental infarctions and a retro placental hemorrhage, also on the basis of sickle cell trait. At birth, placental weight was under the 10th percentile for gestational age. Obstetrical ultrasound in the prenatal diagnosis of proximal femoral focal deficiency is important, because early recognition of this malformation could provide useful information to parents and physicians regarding newborn management and therapeutic planning.

This pictorial essay illustrates the varied imaging appearances of adnexal torsion and its diagnostic pitfalls. This is a difficult diagnosis with many false positives and false negatives. Diagnosis is mostly based on clinical history and ultrasound examination, with computed tomography and/or magnetic resonance used to support the diagnosis and to exclude other pathologies.

With routine antenatal ultrasound and recent advances in ultrasound technology, fetal intraabdominal cystic masses are recognized more often and are better characterized than in the past. They may be classified as solid and cystic, and may originate from multiple structures. When considering the extensive differential diagnosis of cystic masses, the observation of peristalsis narrows the possibilities to the gastrointestinal tract. To find this feature on ultrasound, the examiner must expressly think and look for it, otherwise it may be missed. Our case report illustrates one of those cases.