TAILIEUCHUNG - Ebook Atlas of fetal MRI: Part 2

(BQ) part 1 book “Atlas of fetal MRI” has contents: MR imaging of fetal thoracic abnormalities, MR imaging of the fetal abdomen and pelvis, MR imaging of the fetal extremities, spine, and spinal cord; MR imaging of multiple gestations, and other contents. | 5 MR Imaging of Fetal Thoracic Abnormalities DEBORAH LEVINE INTRODUCTION throughout the third trimester when the lungs display higher signal intensity and larger size than in the early second trimester (9). The aorta, superior vena cava, inferior vena cava, and ductal arch all can be viewed when the image is in the appropriate plane (Figs. – ) (44). The individual chambers of the heart are rarely visualized secondary to constant cardiac motion, but at times, the image is obtained either at just the right time for a single-shot image or at the correct phase of the cardiac cycle such that cardiac gating has occurred for images obtained during a breathhold (Fig. ). A number of publications have described the benefit of magnetic resonance (MR) imaging in the evaluation of fetuses with thoracic abnormalities (1 –10). In a study by Levine et al. (9), of 74 fetuses with thoracic abnormalities, MR imaging provided additional information over sonography in 28 () patients. However, MR information regarding the thorax impacted care in only 6/74 () fetuses. Prenatal thoracic MR is most likely to impact care in the fetal surgery patient and in the cases where the diagnosis is unclear by sonography. The Airway and Esophagus NORMAL ANATOMY The trachea, carina, and mainstem bronchi can be seen in many examinations of the chest (Fig. ). Small portions of the esophagus are commonly visualized (9). The esophagus appears as a tubular structure in the posterior mediastinum. It is best visualized when the image acquisition coincides with the fetus swallowing a bolus of amniotic fluid or reflux occurs. The esophagus is then visualized as it is distended and filled with amniotic fluid (Fig. ). Lung Signal Intensity T2 lung signal intensity in normal lungs is higher in older gestational age fetuses compared with younger gestational age fetuses (Figs. –) (9,11). T1 signal intensity similarly decreases with increasing gestational age (12). Normal lung .

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• Atlas of fetal MRI
• Fetal thoracic abnormalities
• T he fetal abdomen
• The fetal extremities
• Multiple gestations
• MR imaging in pregnancy
• Fetal CNS abnormalities
• The fetal skull
• Safety of MR imaging in pregnancy
• MR imaging of normal brain
• Obstetric triage
• Emergency care protocols
• Periviable obstetric management
• Early complications
• Postabortion complications
• Medical conditions