Fetal liver iron overload: the role of MR imaging.

OBJECTIVE: To assess the potential role of MR imaging in the diagnosis of fetal liver iron overload. METHODS: We reviewed seven cases of abnormal liver signal in fetuses referred to MR imaging in a context of suspected congenital infection (n = 2), digestive tract anomalies (n = 3) and hydrops fetalis (n = 2). The average GA of the fetuses was 31 weeks. The antenatal diagnoses were compared with histological data (n = 6) and postnatal work-up (n = 1). RESULTS: Magnetic resonance imaging demonstrated unexpected abnormal fetal liver signal suggestive of iron overload in all cases. The iron overload was confirmed on postnatal biopsy (n = 2) and fetopathology (n = 4). The final diagnosis was hepatic hemosiderosis (haemolytic anaemia (n = 2) and syndromal anomalies (n = 2)) and congenital haemochromatosis (n = 3). In all cases, the liver appeared normal on US. CONCLUSIONS: Magnetic resonance is the only imaging technique able to demonstrate liver iron overload in utero. Yet, the study outlines the fundamental role of MR imaging in cases of congenital haemochromatosis. The antenatal diagnosis of such a condition may prompt ante-(in the case of recurrence) or neonatal treatment, which might improve the prognosis.

Incidence, mechanisms, and patterns of fetal cerebral lesions in twin-to-twin transfusion syndrome.

OBJECTIVE: To determine the incidence of fetal cerebral lesions and their characteristics in twin-to-twin transfusion syndrome (TTTS). DESIGN AND SETTING: This was a retrospective analysis at a single center for the period 1999 to 2004 in which 299 cases of severe TTTS at 15-28 weeks of gestation were reviewed. METHODS: Only cerebral injuries diagnosed during pregnancy or ischemic lesions diagnosed within the first week of life were considered in order to exclude those related to prematurity. We only included cases resulting in at least one survivor at one week after delivery, as well as fetuses that were terminated because of severe cerebral abnormalities. We excluded all fetuses delivered at <24 weeks of gestation that died prior to undergoing postnatal cranial ultrasonography. The main outcome measures were fetal cerebral lesions, intrauterine death, survival, and neonatal death. RESULTS: Two hundred and ninety-nine pregnancies were evaluated. Three hundred and fifteen fetuses were reviewed. Cerebral abnormalities developed antenatally in 26/315 fetuses (8.25%). All lesions but one were diagnosed prenatally. Prenatal diagnosis of these lesions was achieved primarily by ultrasound (US) and magnetic resonance imaging (MRI), in 20/25 (80%) and in 5/25 (20%) fetuses, respectively. Cerebral abnormalities developed following primary laser coagulation in 12/222 (5.40%), following serial amnioreduction in 9/66 (13.63%), and following expectant management in 3/14 (21.4%) fetuses. Abnormalities developed after single intrauterine fetal death (IUFD) in 14 cases. CONCLUSIONS: Cerebral morbidity in TTTS mainly occurs following vascular disruptive lesions. Both donors and recipients are at risk of developing either ischemic or hemorrhagic lesions. The risk of developing cerebral lesions in single survivors is significantly lower following laser treatment. Combined use of a targeted US and fetal MRI could detect most cerebral abnormalities antenatally. Timing of the triggering event is critical for planning serial US and MRI follow-up examinations.

Imaging diagnosis--left retrocaval ureter and transposition of the caudal vena cava in a dog.

Retrocaval ureter and transposition of the caudal vena cava are each, rare developmental anomalies. We describe the usefulness of static fluid magnetic resonance urography and dynamic contrast-enhanced magnetic resonance urography in the diagnosis of these anomalies. Basic techniques, benefits, and drawbacks of magnetic resonance urography are presented.

Utilidad de la resonancia magnética cerebral fetal en antenatal: como método de exploración complementario a la ultrasonografía / Utility of the cerebral fetal magnetic resonance: as an exploration method complementary to the ultrasonography

La utrosonografía es el examen de elección para la exploración del cerebro fetal in utero, ya sea efectuada vía transabdominal o transvaginal, pero tiene sus limitaciones por lo que en algunas ocaciones debemos recurrir a otro tipo de exámenes complementarios para poder afinar el diagnóstico. Es aquí donde la resonancia magnética (RM) cumple su rol más importante. Se describen 11 casos de malformación cerebral, donde la anomalía más frecuente fue la ventriculomegalia. Vemos que la resonancia magnética cumple un rol muy importante en la evaluación de las estructuras cerebrales, principalmente las de la línea media. La anomalía asociada más frecuente en nuestra casuística fue la agenesia de cuerpo calloso, así como anomalías de la migración neuronal y de la giración o leucomalacia periventricular, lo que además orienta a que el origen de estas fue seguramente secundario a eventos isquémicos.