Clínica de Diagnóstico por Imagem – CDPI, Rio de Janeiro - Brazil.

Definition

Congenital diaphragmatic hernia is an idiopathic birth malformation comprising the Bochdalek diaphragmatic defect with herniation of abdominal viscera into the thoracic cavity and consequent pulmonary hypoplasia.

Incidence

The incidence is approximately 0.25:10,000 births.

Despite advances in diagnosis and postnatal treatment, the overall mortality rate is around 60%, predominantly due to a pulmonary hypoplasia and hypertension. The major prognostic factors are the presence of associated structural defects or chromosomal anomalies (trisomies 13 and 18), early diagnosis, herniation of the liver into the thorax (liver up), and lung-head ratio. Higher (>1.4) or lower values of lung-head ratio (<1.0) for left-sided congenital diaphragmatic hernia, are predictive of survival and demise, respectively. Ultrasound is accurate and allows earlier diagnosis of left-sided congenital diaphragmatic hernia. It is the method of choice for prenatal malformation screening, but it does not always provide sufficient informations to perform an adequate abnormality evaluation. Prenatal magnetic resonance (MRI) is being used for further definition of fetal anatomy.

Case report

We report a case (27-year-old, gravida 1) of left-sided congenital diaphragmatic hernia diagnosed at 13 weeks’ gestation with increased fetal nuchal translucency thickness (2.9 mm). No other associated abnormalities were identified. The karyotype obtained by amniocentesis was normal (46, XY). The lung-head ratio at 26 weeks was 0.8. MRI was performed at 26 and 34 weeks showing liver up. A male infant weighing 3050 g was delivered by Cesarean section at 38 weeks gestation. The neonate died in the second day of life before surgery.

Figure 1: Same ultrasound axial view at 26 week’s gestation.
Figure 2: Ultrasound coronal view at 26 week’s gestation showing the stomach inside the thorax (arrow).

Figures 3, 4: Ultrasound of the cephalic pole and thorax at 26 week’s gestation to calculate the lung-head ratio. The lung-head ratio is obtained multiplying the orthogonal diameters of the right lung at the level of the four heart chambers, at the gestational age of 24-26 week, dividing by the head circumference (in millimeters).

Figures 5, 6, 7: Coronal view on T2-weighted showing lung surface (blue arrow), stomach (red arrow) and the heart displaced to the right hemithorax (green arrow).

Figures 8, 9: Axial view on T2-weighted shows the heart placed to the right side and the stomach in the same place (red arrow). In the figure 10 we can see the normal kidneys (arrows).

Figures 10, 11, 12: Sagittal T2-weighted shows the liver-up (blue arrow) and the stomach in the chest (red arrow).

Figure 13: Sagittal T2-weighted MR image shows the left diaphragmatic hernia. Note the intestinal loops inside left side of the thorax (arrow).

Figures 14, 15: Sagittal T2 and T1 showing the liver-up at 34 weeks (arrows).

Figure 16: Coronal T2 view (34 weeks) showing the heart in the right hemithorax (red arrow) and the liver-up (blue arrow).
Figure 17: Axial T2 view showing small right lung with low signal intensity (red arrow) and the liver-up (blue arrow). Note the heart (green arrow) and the stomach (black arrow).

Figure 18: The lung volumetry by MRI at 34 week’s gestation. To obtain the lung volume, the cross-sectional area of the lung is measured on each transverse section. To calculate the volume for each section, the value of the cross-sectional area was multiplied by that of the section thickness and intersection gap combined. The volumes of all of the sections were then summed to obtain the volume of the entire lung. The calculation was repeated for the contralateral lung, and then the volumes of both lungs were added to obtain the total lung volume.

References

• Albanese CT, Lopoo J, Goldstein RB. Fetal liver position and perinatal outcome for congenital diaphragmatic hernia. Prenat Diagn 1998; 18: 1138-1142.
• Lipshutz GS, Albanese CT, Feldstein VA. Prospective analysis of lung-to-head ratio predicts survival for patients with prenatally diagnosed congenital diaphragmatic hernia. J Pediatr Surg 1997; 32:1634-1636.
• Metkus AP, Filly RA, Stringer MD, Harrison MR, Adzick NS. Sonographic predictors of survival in fetal diaphragmatic hernia. J Pediatr Surg 1996; 31: 148-151.
• Werner   www.thefetus.net/ 2005-10-24-11. MRI, Diaphragmatic Hernia.