Fetal MR Imaging Diagnosis of Pulmonary Agenesis

Magn Reson Med Sci, Vol. 9, No. 3, pp. 149–152, 2010

CASE REPORT

Shigeko KUWASHIMA* and Yasushi KAJI

Department of Radiology, Dokkyo Medical University 880 Kitakobayashi, Mibu-machi, Shimotsuka-gu, Tochigi 321–0293, Japan (Received January 14, 2010; Accepted March 24, 2010)

A woman was referred to our institution with an ultrasound (US) suggestive of right-sided heart in fetus at 34 weeks' gestation. Magnetic resonance (MR) imaging revealed right- sided heart, small right hemithorax, and completely absent right main bronchus and right pulmonary artery. From our experience with this case, we point out 5 important MR imaging ˆndings needed for prenatal diagnosis of pulmonary agenesis. Fetal MR imaging also provided information about anomalies of other organs.

Keywords: fetus, MRI, pulmonary agenesis

nor cardiomegaly was found. The displacement of Introduction the heart to the right and the complete absence of Pulmonary agenesis is the complete absence of the right main bronchus and right pulmonary ar- lung parenchyma with no trace of bronchial or vas- cular supply. Chest radiography at birth may detect characteristic ˆndings of this disease, and computed tomography (CT) may be useful in conˆrming the diagnosis. We present the fetal magnetic resonance (MR) imaging appearance of a case of right pulmonary agenesis.

Case Report A previously healthy 23-year-old woman with no family history of congenital heart disease was referred to our institution for consultation with an outside ultrasonogram (US) performed at 34 weeks' gestation that suggested dextrocardia in fetus. She underwent MR imaging at 34 weeks' gestation on a 1.5-tesla system (Sonata, Siemens Medical Solutions, Erlangen, Germany) using a phased ar- ray coil without premedication (half-Fourier acqui- sition single-shot turbo spin-echo [HASTE] se- quences; repetition time [TR]/echo time [TE]＝ 1000/66; ‰ip angle 150; 4- to 5-mm slice thickness; 300- to 350-cm ˆeld of view [FOV]; matrix 256× 256). Coronal MR imaging revealed the fetus had a right-sided heart, small right hemithorax, left lung almost occupying the left thorax, and absent right Fig. 1. T2-weighted coronal image shows displace- main bronchus (Fig. 1). Neither pleural eŠusion ment of the heart to the right with small right hemithorax and overdistension of the left lung. Note *Corresponding author, Phone: ＋81-282-86-1111, Fax: ＋81- complete absence of the right main bronchus and 282-86-4740, E-mail: shigeko＠dokkyomed.ac.jp normal left main bronchus (arrow).

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Fig. 2. T2-weighted axial image shows complete absence of the right main bronchus and artery with normal left bronchus (arrow) and artery (arrow head). Left lung demonstrates overdistension with homo- Fig. 4. Chest radiograph shows complete opacity geneous normal signal intensity. of the right hemithorax with a marked shift of the heart to the right. Note vertebra segmentation anomaly and rib anomaly.

Fig. 3. T2-weighted axial image shows a horseshoe kidney.

Fig. 5. Coronal reconstruction of computed tomo- tery are apparent in the axial MR imaging (Fig. 2). graphy (CT) shows absent right lung with hyperex- Coronal and axial images of the left lung showed pansion of the left lung. Note the complete absence of the right main bronchus. homogeneous high intensity. MR imaging clearly demonstrated a horseshoe kidney (Fig. 3). The woman delivered a 3,568-gram live male in- fant with Apgar scores of 8 at one minute and 9 at 5 Figure 5 shows the complete absence of the right min. Immediate radiography demonstrated com- main bronchus and Fig. 6, of the right pulmonary plete opacity of the right hemithorax, marked shift artery. Ventricular septal defect (VSD) was identi- to the right of the heart and mediastinum, vertebra ˆed on US. segmentation anomaly, and rib anomalies (Fig. 4). CT of the chest on Day 0 revealed absence of the right lung with hyperexpansion of the left lung.

Magnetic Resonance in Medical Sciences Pulmonary Agenesis 151

Fig. 6. a, b: Contrast-enhanced computed tomography (CT) shows absent right pulmonary artery.

ing ˆndings needed to make a prenatal diagnosis of Discussion pulmonary agenesis: 1) absence of the right lung, Pulmonary agenesis occurs during the embryo- 2) absence of the right main bronchus, 3) absence genic period, at approximately 4 weeks' gestation, of the right pulmonary artery, 4) left lung with when the primitive lung is forming, and its etiology homogeneous normal intensity, 5) abdominal con- is unknown.1,2 The abnormality is usually unilater- tents in the abdominal cavity. al with no predominance by side or gender. The di- Patients with right pulmonary agenesis have agnosis of pulmonary agenesis is usually suspected shorter lives than those with left-lung agenesis, when chest radiography demonstrates a small, which suggests that right pulmonary agenesis has a completely opaque hemithorax with displacement greater frequency of associated shift of the heart of the mediastinum.3 CT and MR imaging may and mediastinum with corresponding distortion of provide important diagnostic information, showing blood vessels and bronchi. More than 50z of chil- the absence of lung parenchyma, bronchial tree, dren with pulmonary agenesis have associated con- and pulmonary vessels on the aŠected side. genital anomalies that involve the cardiovascular, When confronted with a case of a right-sided gastrointestinal, skeletal, and genitourinary sys- heart with small right hemithorax on fetal MR tems. Therefore, after diagnosing pulmonary agen- imaging, the diŠerential diagnosis includes atelec- esis, it is necessary to look for other anomalies. tasis, congenital cystic adenomatoid malformation Fetal MR imaging may provide more information (CCAM), congenital diaphragmatic hernia, and than fetal US about the anatomical details of mal- pulmonary hypoplasia or agenesis. When total formed fetuses; in this case, fetal MR imaging atelectasisoftherightlungoccurs,diŠerentiating demonstrated a horseshoe kidney. Technical ad- the ˆndings from those of right pulmonary agenesis vances in fetal MR imaging have made it an in- may be di‹cult based only on the presence of a creasingly important diagnostic tool in evaluating right-sided heart. Left CCAM can be identiˆed by fetuses with suspected anomalies. However, fetal thepresenceofmultiplecysticlesionsintheleft MR imaging does not provide precise diagnostic in- lung with displacement of the heart and mediasti- formation about congenital heat disease. Pulmona- num to the right.4 Inthecaseofacongenitalleftdi- ry agenesis is usually suggested by fetal US. By ad- aphragmatic hernia, the defect causes abdominal ditionally performing fetal MR imaging, we can contents in the chest that lead to a right-sided conˆrm the diagnosis of this disease and discover heart.5 Right pulmonary hypoplasia shows asym- abnormalities in other organs. This information metrically decreased right lung volume with abnor- had an important eŠect on prenatal counseling. mally low signal intensity.6 In this case, diagnosis was made postnatally. We Conclusions should have researched other important ˆndings after recognizing the right-sided heart. Correct diag- Although prenatal diagnosis of dextrocardia is nosis requires consideration of other characteristic possible with US, fetal MR imaging contributes sig- ˆndings of this disease. From our experience with niˆcantly to the prenatal assessment of pulmonary this case, we point out 5 important fetal MR imag- agenesis and associated congenital anomalies. In

Vol. 9 No. 3, 2010 152 S. Kuwashima and Y. Kaji this study, we have characterized the appearance of 3. Bulas DI, Slovis TL. Pulmonary agenesis, In: Slovis pulmonary agenesis on MR imaging. TL, ed. CaŠey's Pediatric Diagnostic Imaging. 11th ed. Philadelphia: Mosby Elsevier, 2008; 89–92. 4. Hubbard AM, Adzick NS, Crombleholme TM, et References al. Congenital chest lesions: diagnosis and charac- 1. Berrocal T, Madrid C, Novo S, Gutiáerrez J, Ar- terization with prenatal MR imaging. Radiology jonilla A, G áomez-Le áon M. Congenital anomalies of 1999; 212:43–48. the tracheobronchial tree, lung, and mediastinum: 5. Leung JW, Coakley FV, Hricak H, et al. Prenatal embryology, radiology, and pathology. Radiograph- MR imaging of congenital diaphragmatic hernia. ics 2004; 24:e17. Epub 2003 Nov 10. AJR Am J Roentgenol 2000; 174:1607–1612. 2. Daltro P, Fricke BL, Kuroki I, Domingues R, Don- 6. Kuwashima S, Nishimura G, Iimura F, et al. Low- nelly LF. CT of congenital lung lesions in pediatric intensity fetal lungs on MRI may suggest the diag- patients. AJR Am J Roentgenol 2004; 183:1497– nosis of pulmonary hypoplasia. Pediatr Radiol 1506. 2001; 31:669–672.

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