Magnetic resonance imaging of the fetal lung: a pictorial essay

Abstract

Ultrasound, which is now a widely available and generally accepted, low-cost technique with real-time properties, is the screening investigation of choice in fetal medicine. However, enthusiasm for fetal prenatal magnetic resonance imaging (MRI) is rising, because of the absence of known biological risks, the increasing ease of performing of fetal MRI and the superb contrast resolution provided. Over the last 10 years, the technology has advanced dramatically. Fast imaging sequences have allowed better MRI visualization of the unborn patient than ever before. As a consequence, experience with fetal MRI is gradually expanding. We are beginning to appreciate the clinical conditions where fetal MRI can complement the ultrasound findings. Apart from the central nervous system, MRI of the fetal lung has received the most attention. Fetal MRI can be used to assess thoracic structural anomalies, lung development as well as maturation. The introduction of fetal therapy for severe lung hypoplasia, associated with congenital diaphragmatic hernia (CDH), has recently boosted the application. This review aims to highlight MRI techniques used to image the lungs of the unborn child and to point out their strengths and limitations in specific conditions.

Prenatal diagnosis of congenital lung malformations

“…The diagnosis is verified with color Doppler (and sometimes with MRI) by the presence of an abnormal vascular supply arising from the aorta or its major branches (Fig. 5) [11,12]. If the vascular supply is not recognized, BPS is indistinguishable from other congenital lung abnormalities, such as CPAM, bronchial atresia and CLO [12,17].…”

“…Occasionally, they may cause secondary bronchial compression that causes morphological changes in the lung distal to the obstruction: increase of volume and retention of foetal lung fluid. The retained fluid is homogeneously hyperechoic and is hyperintense on T2-weighted MRI [12]. In case of bronchial obstruction, the differential diagnosis includes bronchial atresia.…”

“…4). These cysts are easily recognisable on T2-weighted images [10][11][12]. In large lesions, the expansion of the pathological lung may cause mediastinal shift and secondary compression of the contralateral lung (Fig.…”

Congenital Chest Malformations: A Multimodality Approach with Emphasis on Fetal MR Imaging

“…In addition, some chest malformations occupy the thorax and alter normal pulmonary development, causing hypoplastic lung formation. These pulmonary abnormalities are not mutually exclusive, since abnormalities frequently occur together as hybrid conditions (3)(4)(5)(6).…”

Diagnosis of Diaphragmatic Hernia with Associated Congenital Lung Lesions: Contribution of Fetal MRI

“…US is a bedside, real-time technique with low cost, high availability and general acceptance [13] , and remains the initial imaging modality of choice to determine fetal pulmonary structure and size. However, MRI, due to its superior tissue contrast resolution, larger field of view, lack of shadowing artifact and relative operator independence, can provide valuable complementary information [13] . Absence of shadowing artifact not only allows full qualitative but also quantitative assessment of the ipsilateral lung in CDH.…”