MRI In Pregnancy Research Articles

MRI based morphological examination of the placenta.

Ultrasound is widely used as the initial diagnostic imaging modality during pregnancy with both high spatial and temporal resolution. Although MRI in pregnancy has long focused on the fetus, its use in placental imaging has greatly increased over recent years. In addition to the possibilities of evaluating function, MRI with a wide field of view and high contrast resolution allows characterization of placental anatomy, particularly in situations that are difficult to specify with ultrasound, especially for suspected placenta accreta. MRI also appears to be a particularly useful examination for the anatomical evaluation of the placenta independent of maternal body habitus or fetal position. Indeed, surprisingly little attention is paid to the placenta in MRI when the indication for the examination is fetal. Thus, some aspects of the placenta seem to us to be important to be recognized by the radiologist and to be described on the MRI report. In this review, we will describe MRI sequences used for, and common features seen in, imaging of i) the normal placenta, ii) abnormal aspects of the placenta that should be identified on MRI performed for fetal reason, and iii) placental anomalies for which placental MRI may be indicated.

Quantitative ferumoxytol-enhanced MRI in pregnancy: A feasibility study in the nonhuman primate

ObjectivesTo assess the feasibility of ferumoxytol-enhanced MRI in pregnancy with a nonhuman primate model. Materials and methodsIn this prospective study, eleven pregnant rhesus macaques at day 98 ± 5 of gestation were divided into three groups, untreated control (UC) (n = 3), saline control (SC) (n = 4) and interleukin 1 beta (IL-1β) treated (IT) (n = 4), which were administered with either saline or IL-1β into the amniotic fluid. All animals were imaged at multiple time points before and after ferumoxytol administration (4 mg/kg). Longitudinal R2* and susceptibility of tissues were obtained using region-of-interest analysis and the longitudinal changes were assessed using linear mixed models and Student's t-test. ResultsIn fetuses, a slope of 0.3 s−1/day (P = 0.008), 0.00 ppm/day (P = 0.699) and − 0.2 s−1/day (P = 0.023) was observed in liver R2*, liver susceptibility, and lung R2*, respectively. In placentas, R2* and susceptibility increased immediately after ferumoxytol administration (P < 0.001) and decreased to baseline within two days. The mean change from baseline showed no significant difference between the SC group and the IT group at all scan time points. In maternal livers, R2* increased immediately after ferumoxytol administration, further increased at one-day, and then decreased but remained elevated (P < 0.001). The mean change from baseline showed no significant difference between the SC group and the IT group at all scan time points. ConclusionsThis work demonstrates the feasibility of quantitative ferumoxytol-enhanced MRI to measure dynamics of ferumoxytol delivery and washout in the placenta. Stable MRI measurements indicated no evidence of iron deposition in fetal tissues of nonhuman primates after maternal ferumoxytol exposure.

MRI in pregnancy: Indications and practical considerations.

There is a constantly evolving knowledgebase regarding the safety of MRI in pregnant patients, as well as the safety of gadolinium administration, given potential fetal risks. This review provides an overview of national and international recommendations for patient screening and safety by trimester, evaluates the most recent literature regarding administration of gadolinium in pregnant patients, and discusses technical requirements when imaging pregnant patients. A protocol for imaging pregnant patients is provided, and multiple common indications for MRI in pregnancy are discussed. Level of Evidence 5. Technical Efficacy Stage 5. J. Magn. Reson. Imaging 2019;49:621-631.

MRI in pregnancy: Gastrointestinal and genitourinary pathology

MRI in pregnancy: Gastrointestinal and genitourinary pathology

The use of MRI to demonstrate small bowel obstruction during pregnancy

Patients who present during pregnancy with acute abdominal symptoms often present a significant diagnostic challenge. Although ultrasound is often the first mode of abdominal imaging, in complex cases further imaging is often necessary. MRI of the small bowel has been made possible with the development of rapid scanning techniques. This has increased the attractiveness of a modality whose benefits include multiplanar imaging, excellent soft tissue contrast and the avoidance of ionizing radiation. With these capabilities MRI has been shown to be a useful adjunct when imaging the small bowel in pregnancy. Although MRI has been employed to investigate small bowel obstruction in the obstetric setting, to date there have been no reports of MR identifying small bowel obstruction secondary to extrinsic compression from a gravid uterus. During pregnancy, small bowel obstruction is most commonly attributed to adhesions. However, there are also antenatal occurrences of small bowel obstruction secondary to uterine compression. We present the MRI findings of an unusual case of small bowel obstruction occurring secondary to compression from a 32-week gravid uterus, in a patient with an end ileostomy. Furthermore, while clinical history and examination are fundamental to diagnosis of intestinal obstruction, the following case highlights the value of MRI in pregnancy as a confirmatory test.