Epidemiology

Congenital diaphragmatic hernias are seen in 1 of every 2000-4000 live births. 84% are left-sided, 13% are right-sided and 2% bilateral 6.

Clinical presentation

Most congenital diaphragmatic hernias are detected either soon after birth or on antenatal ultrasound. Mortality is predominantly due to the development of pulmonary hypoplasia, which is thought to be due to the mass effect on the developing lung. Such neonates are hypoxic and have persistent fetal circulation due to pulmonary hypoplasia and pulmonary hypertension.

Pathology

Diaphragmatic development is usually complete by ~9th week of gestation. Congenital diaphragmatic hernias result from failure of fusion of one of the pleuroperitoneal canals at about 8 weeks gestation. They may contain the stomach, intestines, liver, or spleen.  

Types

Congenital diaphragmatic herniation can be grouped into two basic types on location:

1. Bochdalek hernia

   • most common fetal congenital diaphragmatic hernia

   • more common on the left: 75-90%

   • posterolateral

   • large and associated with poorer outcome

   • presents earlier

   • mnemonic: BBBBB

2. Morgagni hernia

   • less common

   • anterior

   • presents later 

Associations

While a CDH can occur as an isolated condition, associated anomalies are relatively common and include:

• pulmonary hypoplasia: also a complication

• left ventricular hypoplasia due to impaired umbilical venous return 19

• early ventricular dysfunction, about 40% 18

• intestinal malrotation: in up to 45% of cases 17

• bronchopulmonary sequestration

• aneuploidy: can be present in up to 50% of cases ref

  • trisomy 13

  • trisomy 18

  • trisomy 21

  • Turner syndrome: monosomy X

  • Pallister-Killian syndrome: tetrasomy 12p

• Fryns syndrome

• Cornelia de Lange syndrome

• congenital cardiac anomalies

• neural tube defects

  • anencephaly

  • spina bifida

Radiographic features

Plain radiograph

• indistinct diaphragm with opacification of part of or all the hemithorax (typically left sided)

• scaphoid abdomen

• deviation of lines 3

  • endotracheal tube

  • nasogastric tube

  • umbilical arterial and venous catheters

Antenatal ultrasound

Indirect sonographic findings that should prompt a search for CDH include 7:

• polyhydramnios

• cardiomediastinal shift +/- abnormal cardiac axis

• inability to demonstrate the normal stomach bubble

The study should be performed in the true transverse plane. Sonographic diagnosis of CDH can be made from the following findings 7,8:

• absent bowel loops in the abdomen

• intrathoracic herniation of the liver; noted in up to 85% of cases and is associated with a worse prognosis

• peristaltic bowel movements in the chest

• herniation into the chest may occur intermittently

• abdominal circumference is reduced (due to herniation of organs)

• left-sided CDH

  • stomach and small bowel (echo-free) at the same transverse level as the heart on four-chamber view: this makes left sided hernias comparatively easier to detect on ultrasound (as opposed to herniation of echogenic liver on the right side)

  • stomach and small bowel superior to the inferior margin of the scapula

  • leftward displacement of the gallbladder 

• right-sided CDH

  • color Doppler study

    • leftward bowing of the umbilical segment of the portal vein

    • portal branches to the lateral segment of the left hepatic lobe coursing towards or above the diaphragm

  • gallbladder present above the diaphragm

  • echogenic space between the left heart border and stomach representing the left hepatic lobe

Although classically considered a cystic echogenic lung mass, there are reports of CDH appearing initially as a solid echogenic lung mass that evolves in appearance with advancing gestation 9.

The observed-to-expected lung-to-head ratio (O/E LHR) may be calculated and correlates with the degree of pulmonary hypoplasia. Studies suggest that the degree of lung hypoplasia can be used to predict survival rates and the numbers from the Antenatal-CDH-Registry group that apply to isolated left-sided CDH and liver herniation are shown below 10,11:

• O/E LHR <15% (extreme pulmonary hypoplasia): virtually no chance of survival

• O/E LHR 15-25% (severe pulmonary hypoplasia): predicted survival ≈ 15%

• O/E LHR 26-45% (moderate pulmonary hypoplasia): predicted survival 30-75%

• O/E LHR >45% (mild pulmonary hypoplasia): very likely to survive

MRI

Fetal MRI may be helpful in further assessing the hernia and any associated pulmonary hypoplasia. 

Sequences typically performed for assessment of CDH include 12,13:

• T2 weighted three-plane single shot fast spin echo (SSFSE) 

  • fluid filled stomach and small bowel appear hyperintense

• T2 weighted balanced steady state free precession (bSSFP) 

  • flowing blood appears hyperintense: portal vessels may be seen extending toward or above the diaphragm

• T1 weighted fast field echo (FFE) 

  • liver appears moderately hyperintense

• T2 weighted half-fourier acquisition single-shot turbo spin echo (HASTE) 

  • lungs appear hyperintense (composed primarily of water) while heart, mediastinum and liver appear hypointense

Lung-head ratio: can be assessed on both ultrasound or MRI; MRI measured LHR has been found to have a slightly higher prognostic accuracy than with ultrasound 5. 

MRI allows the measurement of fetal lung volumes which provide an estimate of the severity of pulmonary hypoplasia. The total fetal lung volume (TFLV) can be calculated from a contiguous T2-weighted HASTE sequence and an observed-to-expected TFLV (O/E TFLV) derived. It has been found to predict well both mortality and morbidity, including the need for ECMO and the development of bronchopulmonary dysplasia 14,15.

Treatment and prognosis

Fetuses with an antenatal diagnosis of CDH should be delivered in a tertiary referral center with access to neonatal intensive care and pediatric surgical facilities.

Large CDH have a poor prognosis, due to pulmonary hypoplasia and perinatal mortality may be as high as 80%. Successful management is dependent on specialist pediatric facilities, with the ability to offer surgery, ECMO etc.

Acute postnatal circulatory changes elevate LV afterload and increase pulmonary venous pressure exacerbating ventricular dysfunction 19.

Signs suggesting a poor prognosis include:

• large hernia size

• early gestational age at diagnosis

• intra-thoracic liver

• small contralateral lung

• pulmonary hypertension 20

• early ventricular dysfunction especially biventricular dysfunction 18

• the presence of associated abnormalities

• bilateral CDH

• unfavorable lung: head ratio

A composite prognostic index (CDH-CPI) comprising 10 prenatal parameters has been developed and was found to have a stronger correlation with survival and need for ECMO than any one parameter individually 16. 

Some centers perform in utero surgery in selected cases. One such surgical approach is the fetoscopic endotracheal occlusion (FETO) procedure, in which the fetal trachea is temporarily occluded by a balloon to allow expansion of the fetal lungs with fluid and consequently prevent some degree of pulmonary hypoplasia 21. A randomized controlled trial demonstrated a survival benefit in severe CDH 21.

Complications

• development of pulmonary hypoplasia

• development of pulmonary hypertension

  • severity may be predicted by the modified McGoon index

• cardiac dysfunction: RV, LV or combined

0

Fetal Radiopedia

August 14, 2024

 

this artical by : https://obgyn.onlinelibrary.wiley.com

Abstract

Objective

To describe a new sign of cleft lip and palate (CLP), the maxillary gap, which is visible in the mid-sagittal plane of the fetal face used routinely for measurement of nuchal translucency thickness.

Methods

This was a retrospective study of stored images of the mid-sagittal view of the fetal face at 11–13 weeks' gestation in 86 cases of CLP and 86 normal controls. The images were examined to determine if a maxillary gap was present, in which case its size was measured.

Results

In 37 (43.0%) cases of CLP the defect was isolated and in 49 (57.0%) there were additional fetal defects. In the isolated CLP group, the diagnosis of facial cleft was made in the first trimester in nine (24.3%) cases and in the second trimester in 28 (75.7%). In the group with additional defects, the diagnosis of facial cleft was made in the first trimester in 46 (93.9%) cases and in the second trimester in three (6.1%). A maxillary gap was observed in 96% of cases of CLP with additional defects, in 65% of those with isolated CLP and in 7% of normal fetuses. There was a large gap (>1.5 mm) or complete absence of signals from the maxilla in the midline in 69% of cases of CLP with additional defects, in 35% of those with isolated CLP and in none of the normal controls.

Conclusions

The maxillary gap is a new simple marker of possible CLP, which could increase the detection rate of CLP, especially in isolated cases. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

INTRODUCTION

Cleft lip and palate (CLP) is a common congenital defect that can be either isolated or associated with a wide range of chromosomal abnormalities and genetic syndromes. Isolated cleft lip or cleft palate may escape prenatal detection, but combined CLP is diagnosed easily during the routine second-trimester scan1, 2.

In the last decade, widespread use of the 11–13-week scan in screening for aneuploidies with measurement of fetal nuchal translucency (NT) thickness has resulted in many major fetal defects being diagnosed in the first trimester of pregnancy3. This can be achieved by direct visualization of the fetal anatomy, for example in cases of anencephaly, exomphalos and megacystis3, or by focused assessment of specific fetal structures triggered by the finding of indirect signs, for example increased NT in association with major cardiac defects4, 5 and abnormal intracranial translucency (IT) in association with open spina bifida6-9.

Most cases of CLP are not detected during the first-trimester scan3. Improved detection may be achieved by targeted examination of the face in a coronal view and assessment of the retronasal triangle10. However, the uptake of such assessment may be limited by the necessity to include examination of a plane additional to the standard mid-sagittal view that is necessary for measurement of fetal crown–rump length, NT, nasal bone (NB) and IT.

The objectives of this study were first, to describe a new sign of CLP, the maxillary gap, visible in the mid-sagittal plane of the fetal face, which is used routinely for measurement of NT, NB and IT (Figures 1 and 2) and, second, to provide preliminary data on the potential value of the maxillary gap in the early diagnosis of CLP.

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Figure1

Figure 1

Open in figure viewerPowerPoint

Standard mid-sagittal view of the fetal face used routinely at 11–13 weeks, illustrating the maxilla in a normal fetus (a) and the maxillary gap (open arrow) in a fetus with cleft lip and palate (b).

Figure 2

Open in figure viewerPowerPoint

Ultrasound images in the mid-sagittal plane of the face in a normal fetus with no maxillary gap (a), a normal fetus with small maxillary gap (arrow) (b) and four fetuses with cleft lip and palate, showing partial (c,d,e) or complete (f) maxillary gap (arrows).

SUBJECTS AND METHODS

In three cases of CLP we made an incidental observation that, in the mid-sagittal view of the fetal face at 11–13 weeks' gestation, there was a gap in the echogenic line representing the palate; no such gap was observed in 10 consecutive cases of normal fetuses. We therefore subsequently conducted a search of the databases of two major centers of prenatal diagnosis, to identify fetuses with CLP which underwent routine first-trimester screening for aneuploidies. The stored images of the mid-sagittal view of the face in these cases were retrieved and for each case a control was selected: a fetus examined on the same day that was subsequently liveborn without any abnormality.

The diagnosis of CLP was made in a coronal view of the face. In most cases which underwent termination of pregnancy, diagnosis was confirmed clinically or at autopsy. Cases with isolated cleft lip or cleft of the posterior palate were not included in the study. Transabdominal ultrasound examinations were performed initially as part of routine NT screening and, in the presence of fetal malformations, an additional transvaginal examination was performed selectively.

All retrieved images of cases and controls were assessed offline by two independent examiners (R.C., G.O.) who were unaware of the final diagnosis. The images were examined to determine if a maxillary gap was present; if this was the case we determined whether it was partial or complete (Figure 2) and measured the size of the gap. Ultrasound findings and pregnancy outcome data were obtained from the databases and their relation to the maxillary gap was examined.

RESULTS

The study population comprised 86 cases of CLP with satisfactory images of the mid-sagittal view of the fetal face at 11–13 weeks, identified from the combined databases of the two centers. The characteristics of the study population and controls are summarized in Table 1. In the controls no defect was detected in either the first- or the second-trimester scan and all pregnancies resulted in healthy live births with no defects.

Table 1. Characteristics of study group of 86 fetuses with facial cleft and 86 normal controls

Characteristic	Normal controls (n = 86)	Facial cleft
		Isolated (n = 37)	Other defects (n = 49)
Maternal age (years)	32 (30–36)	32 (26–35)	34 (28–39)
Gestational age (weeks)	12.6 (12.3–12.7)	13.0 (12.7–13.3)	12.7 (12.1–13.3)
Crown–rump length (mm)	61.0 (57.3–64.0)	68.3 (63.5–72.9)	60.2 (54.6–68.3)
Nuchal translucency thickness (mm)	1.6 (1.4–1.9)	1.9 (1.7–2.1)	2.8 (1.9–4.9)
Fetal karyotype
Normal or normal live birth	86 (100)	37 (100)	12 (24.5)
Trisomy 13	—	—	23 (46.9)
Trisomy 18	—	—	9 (18.4)
Other	—	—	3 (6.1)
Unknown	—	—	2 (4.1)
Cleft location
Median	—	—	12 (24.5)
Bilateral	—	7 (18.9)	26 (53.1)
Unilateral	—	30 (81.1)	11 (22.4)
Maxillary protrusion	—	7 (18.9)	20 (40.8)
Time of diagnosis
First trimester	—	9 (24.3)	46 (93.9)
Second trimester	—	28 (75.7)	3 (6.1)
Outcome
Live birth	86 (100)	33 (89.2)	2 (4.1)
Neonatal death	—	1 (2.7)	—
Termination of pregnancy	—	3 (8.1)	45 (91.8)
Fetal death	—	—	2 (4.1)

• Data are given as median (interquartile range) or n (%).

The diagnosis of facial cleft was made in the first trimester in 55 (64.0%) and in the second trimester in 31 (36.0%) of the CLP cases (Table 1). The diagnosis was suspected in the first trimester in some cases due to maxillary protrusion or to the presence of associated anomalies and was confirmed by examining a coronal view of the face and the oblique view of the retronasal triangle.

In 37 (43.0%) cases the facial cleft was an isolated finding; in three (8.1%) of these the pregnancy was terminated at the request of the parents, one (2.7%) underwent neonatal death due to birth asphyxia and in 33 (89.2%) the pregnancy resulted in live birth and the infant underwent surgery for correction of the defect. In this group with isolated CLP the diagnosis of facial cleft was made in the first trimester in nine (24.3%) cases and in the second trimester in 28 (75.7%).

In 49 cases of CLP there were additional fetal defects. In 47 cases fetal karyotyping following chorionic villus sampling or amniocentesis was carried out; the karyotype was normal in 12 (25.5%) and abnormal in 35 (74.5%), including 23 cases of trisomy 13, nine of trisomy 18 and three other chromosomal abnormalities. In 45 cases the pregnancy was terminated at the request of the parents, two fetuses died in utero and in two the pregnancy resulted in live birth and the infant underwent surgery for correction of the defect. In this group with additional defects the diagnosis of facial cleft was made in the first trimester in 46 (93.9%) cases and in the second trimester in three (6.1%).

A maxillary gap was observed in six (7.0%) of the controls, in 24 (64.9%) cases with isolated CLP and in 47 (95.9%) cases of CLP with additional abnormalities (Table 2). Figure 2 illustrates partial and complete maxillary gaps. The size of the gap in all six controls was < 1.5 mm. Of the 24 cases of isolated CLP with a maxillary gap, its size was < 1.5 mm in 11 (45.8%) and 1.5–5.0 mm in 13 (54.2%). Of the 47 cases with CLP, additional defects and a maxillary gap, the gap size was < 1.5 mm in 13 (27.7%), 1.5–5.0 mm in 21 (44.7%) and complete in 13 (27.7%); in eight of the latter fetuses there was holoprosencephaly and a median facial cleft.

Table 2. Type and size of maxillary gap in 86 fetuses with facial cleft and 86 normal controls

Maxillary gap characteristic	Normal controls (n = 86)	Facial cleft
		Isolated (n = 37)	Other defects (n = 49)
Type
No gap	80 (93.0)	13 (35.1)	2 (4.1)
Partial gap	6 (7.0)	24 (64.9)	34 (69.4)
Complete gap	—	—	13 (26.5)
Size
< 1.5 mm	6 (100)	11/24 (45.8)	13/47 (27.7)
1.5–5 mm	—	13/24 (54.2)	21/47 (44.7)
Complete	—	—	13/47 (27.7)

• Data are given as n (%).

Protrusion of the maxilla in the profile view was observed in 20 (40.8%) of the 49 fetuses with CLP and additional abnormalities and in seven (18.9%) of the 37 cases with isolated CLP (Table 1).

DISCUSSION

This study demonstrates that CLP can be suspected at 11–13 weeks' gestation in the presence of a maxillary gap in the standard mid-sagittal view of the fetal face that is used routinely in screening for chromosomal abnormalities. A maxillary gap was observed in 96% of cases of CLP with additional abnormalities, in 65% of those with isolated CLP and in 7% of normal fetuses. There was a large gap or complete absence of signals from the maxilla in the midline in 69% of cases of CLP with additional abnormalities, in 35% of those with isolated CLP and in none of the normal controls.

At the end of complex embryological development of the midline of the face between 6 and 12 weeks' gestation, the nose and lip are formed and the palate closes. Anatomically, the palate is then composed of three parts: the anterior or primary palate, including the alveolar ridge, the posterior or secondary palate and the soft palate11. At the time of the 11–13-week scan, some parts of the maxilla may still show lack of ossification. This may explain the finding of a gap in some of the normal controls: in all of these, the size of the suspected gap was very small (< 1.5 mm). Therefore, suspicion of a small maxillary gap in the mid-sagittal view in the presence of an intact maxilla in the coronal view can be considered as a normal finding.

The diagnosis of CLP was made at the 11–13-week scan in 94% of the cases with other abnormalities, but in only 24% of those with isolated CLP. This is not surprising because, in the presence of often multiple sonographic defects, a systematic search is undertaken for additional defects, including CLP, especially in cases with suspected trisomy 18 or 13.

Examination of the maxilla in the mid-sagittal view of the fetal face at 11–13 weeks has been reported previously, in studies which focused mainly on its length in normal fetuses and in fetuses with trisomy 21 or on its use as a landmark for calculation of the frontomaxillary facial angle12-15. Our present study emphasizes a new aspect of early assessment of the maxilla: looking for a maxillary gap as a potential marker of CLP.

In the prenatal diagnosis of facial cleft the typical recommended views during the second-trimester scan are the axial view of the maxilla and the coronal view of the nose and lip11, 16, 17. The importance of the mid-sagittal view of the palate was reported recently for demonstration of the so-called ‘equals sign’ corresponding to the anatomical appearance of the soft palate and uvula18. It was suggested that, in the first trimester, identification of cleft palate necessitates a coronal view of the anterior bony face and demonstration of the retronasal triangle10. Some studies have reported on the use of the retronasal triangle view with three-dimensional (3D) ultrasound to demonstrate CLP and retrognathia19-22. However, the retronasal triangle plane on two-dimensional (2D) or on 2D in combination with 3D ultrasound has not been accepted widely as a standard view in routine screening. In contrast, we have highlighted the importance of the maxillary gap as a marker of possible CLP because the marker is visible in the standard plane that is obtained routinely in screening for aneuploidies.

The main strength of the study is the large number of affected cases with stored images of quality acceptable for assessment. The main limitation relates to its retrospective nature and reliance on stored images. Although for the cases of CLP detected in the first trimester there were numerous images and video recordings, for those in which the diagnosis was missed there were only a few stored images for assessment.

In conclusion, examination of the mid-sagittal view of the fetal face, which is performed routinely for assessment of fetal NT, NB and the posterior brain region, can identify a maxillary gap and lead to first-trimester diagnosis of CLP. In cases of maxillary gap, the sonographer should undertake detailed examination of the face and palate regions. Prospective large studies are necessary to determine the performance of the maxillary gap in screening for facial clefts.

0

Fetal Radiopedia

August 14, 2024