FETAL CHESTFETAL HEART

FETAL CHESTDIAPHRAGM

◦ Assess diaphragm (thin echogenic line) Diaphragm hernias

Lung and bowel similar echogenicity- Look for peristalsis

Left easier to see than right due to gastric bubble

LUNGS◦ Look for pulmonary masses

CCAM Sequestration

◦ Pulmonary hypoplasiaPLEURA - effusionsMEDIASTINUM - masses

CONGENITAL DIAPHRAGM HERNIABochdalek - 90% on left; most unilatAll should have amniocentesis and

dedicated echoSecondary pulmonary hypoplasia is

major cause of mortalityFindings

◦ Polyhydramnios◦ Stomach/bowel/liver adjacent to heart◦ Peristalsis in chest◦ Mediastinal shift◦ Absent gastric bubble◦ Reduced abdominal circumference

compared to rest of fetal biometry

Associated anomalies◦ Aneuploidy (T18, T21); NTD; CHD; malrotation, omphalocele

DDX◦ CCAM◦ Other cystic masses such as foregut duplication cysts are

rare

CCAM Most common fetal lung mass Types I-III

◦ Types I and II macroscopic cysts >5mm with good prognosis and hydrops is rare

Small risk of malignant degeneration (rhabdomyosarcoma) Imaging

◦ Macroscopic types appear cystic◦ Microscopic types appear solid (echogenic)

Pulmonary hypoplasia of normal lung - degree determines prognosis Mediastinal shift - cardiac compromise; polyhydramnios (impaired

swallowing) Associations (type II)

◦ Cardiac anomalies◦ Pulmonary sequestration◦ Pectus excavatum◦ Jejunal atresia◦ Renal agenesis, prune-belly syndrome

Pathology◦ Hamartomatous proliferation of terminal bronchioles◦ Cysts lined by respiratory epithelium and communicate with airways at birth

CCAM

EXTRALOBAR SEQUESTRATION More common in males (4:1) 90% LLL or below diaphragm Always airless as it has its own pleural envelope and no

communication with bronchial tree Systemic arterial supply - Aorta 80% Systemic venous drainage - IVC, azygos, portal v Imaging Findings

◦ Solid hyperechogenic mass◦ Look for systemic arterial supply on Doppler◦ Polyhydramnios◦ Hydrops

Associations 65%◦ CDH◦ Cardiac◦ GI, Renal, Vertebral anomalies

Often regress in utero DDX

◦ CCAM◦ Congential lobar emphysema (initially filled with fetal fluid)◦ Neuroblastoma

SEQUESTRATION

PULMONARY HYPOPLASIAAgenesis – complete absence of one or both lungs

(airways, alveoli, and vessels)Aplasia – absence of lung except for a rudimentary

bronchus that ends in a blind pouchHypoplasia – decrease in number and size of

airways and alveoli◦ Primary◦ Secondary

Bilateral - Oligohydramnios (Potter’s sequence); Skeletal dysplasia

Unilateral - CCAM; Sequestration; CDH; Hydrothorax

Imaging◦ Reduced thoracic circumference (<2SD) is suggestive◦ Fetal lung maturity best sssessed with

lecithin:sphingomyelin ratio in amniotic fluid◦ Echogenic pattern unreliable marker for maturity

PLEURAL EFFUSION = abnormalFetal hydropsChromosomal Underlying mass InfectionLymphangiectasiaChylothorax - assoc with T21 and Turner’s

MEDIASTINAL MASSESAnterior Medistinum

◦ Teratoma◦ Cystic hygroma◦ Normal Thymus

Posterior Mediastinum◦ Neurogenic tumours◦ Enteric cyst

FETAL HEARTTechnique Abdominal situs view

◦ 4-chamber view◦ LVOT

Posterior/central to RVOT Runs left to right

◦ RVOT Anterior to LVOT Runs right to left Bifurcates early: DA and RPA Check for antegrade flow in DA Anatomical trifurcation: DA, RPA, LPA

◦ 3-vessel view amniocentesis indicated in all abnormal: 15-40% will have

chromosomal anomalies ventricles/atria are of roughly same size as other ventricle/atria 3 in 1 rule: heart fills 1/3 of axial chest Cardiac circumference 1/2 chest circumference Length atrial septum: ventricular septum 1:2 Normal HR: 120-160bpm, SR

Best seen on Four-Chamber View◦ Septal defect◦ Endocardial cushion defect (AVSD)◦ Hypoplastic left heart◦ Ebstein’s anomaly◦ Critical AS◦ Coarctation

Best Seen on Outflow Tract Views◦ Tetralogy of Fallot◦ Transposition◦ Truncus Arteriosus◦ Pentalogy of Cantrell

3-VESSEL VIEW

Maternal Risk Factors for CHDDiabetesInfection - rubella, CMVSLEDrugs - EtOH, Phenytoin, lithiumFHX of heart disease, previous

child with CHDArrhythmia

VSDMost common CHD (1:1000)Membranous 80% vs Muscular 10% vs

Outlet (ECD) 5%Don’t mistake membranous to

muscular transition for VSD

Endocardial Cushion Defect40% have Trisomy 21EC forms lower atrial septum,

superior ventricular septum, anterior MV leaflet and septal TV leaflet

Transposition of Great VesselsAorta arises from RV and pulmonary trunk

from LVAorta and pulmonary artery are parallel

instead of perpendicular to each other

Tetralogy of Fallot Tetralogy

◦ Infundibular RV outflow tract stenosis◦ Overriding aorta◦ VSD◦ Hypoplastic RV

LV and RV are symmetric due to equal pressures Often missed on 4-chamber view

Ebstein’s AnomalySeptal and posterior leaflets of tricuspid valve

prolapse and are integrated into RV wallAtrialisation of RVLarge RA due to massive regurgMaternal lithium is a risk factor

Pulmonary AtresiaHypoplastic RA and RVPulmonary artery calibre may be

normalReversed flow in DA

Pericardial Effusion>2mmAssociated with hydrops fetalis,

congenital infection and cardiac anomalies

Look for fluid in other compartments (hydrops)

Look for signs of congential infections◦Cerebral calcification◦Hepatic calcifciation◦Echogenic bowel

Endocardial FibroelastosisIncreased echogenicity of

endocardiumVentricular dilatation and poor

contractility

Ectopia Cordis

Rhabdomyoma Hamartoma of myocytes Strong association with Tuberous Sclerosis

◦ 50-85% of fetuses with it have TS◦ 50% of TS have it

Echogenic mass, usually intraventricular, can arise from IV septum

FETAL ARRHYTHMIASPAC and PVC common and benignSVT is the most common

tachyarrhythmia - CMX hydropsFetal bradycardia (HR <100 for

>10sec)◦ If persistent - consider structural cardiac

defects or maternal CVDFetal heart block

◦ 40-50% have structural abnormality - usually lethal

◦ Associated with maternal SLE, RA, Scleroderma