Congenital Heart Disease and Radiology

Congenital Heart Disease and Radiology

Ankit L. PansaraChicago Medical School

What is the role of the radiologist in assessing suspected CHD?

The INITIAL role of the radiologist is to evaluate the chest radiograph and to provide an ordered, logical differential diagnosis.*It is usually not possible to give a precise diagnosis in these cases (using plain film).

MR may be used to assess cardiac chamber size and position, wall thickness, the presence of intracardiac shunts, and the position of the coronary arteries.

What are the most common acyanotic CHDs? The first consideration in diagnosing

CHD should be whether the infant is clincally cyanotic.

Acyanosis implies a left-to-right shunt, and the most common causes include ASD, VSD, PDA, and endocardial cushion defects.

These typically cause enlargement of specific chambers.

CXR evaluation of cardiac chamber size

RA: right heart border on frontal view

RV: anterior heart border on lateral view

LA: posterior-superior heart border on lateral view

LV: left inferior heart border on frontal view

VSD Diagnosis on CXR Isolated small VSD: normal heart size and

vascularity Moderate defects with normal PA pressures but

high flow: increased vascular markings and varying degrees of cardiomegaly

Large defects with significant L-to-R shunting: increased pulmonary vascular markings, cardiomegaly, prominent PA segments, splaying of the R and L bronchi, and LA enlargement

Large defects with pulmonary vascular dx: RVH with upturned apex and prominent proximal PA segments in the absence of increased vascular markings in the periphery. Heart size often appears to be normal.

VSD results in enlarged RV, PA, and LA

VSD

ASD Diagnosis on CXR

Mild to moderate cardiomegaly with a large RA, RV, and PA segment

Pulmonary vascular markings are increased

Enlargement of the RV is often only manifested on a lateral view.

Many patients will have a normal CXR

ASD results in enlarged RA and RV(this has been closed with a transvenous “cardioseal” device

PDA Diagnosis on CXR

The findings vary in proportion to the degree of the L-to-R shunting

With a larger shunt, there is cardiomegaly with enlargement of the LV, LA, and prominent pulmonary vasculature

PDA results in enlargement of PA, LA, and LV

How does assessment of pulmonary blood flow aid in the diagnosis of cyanotic CHD?

Cyanosis implies either admixture of oxygenated and deoxygenated blood, which would appear as increased blood flow to the heart, or that blood is shunted away from the lungs, which would appear as decreased blood flow.

* Assessment of blood flow includes looking for shunt vessels at the periphery of the lung fields of behind the liver shadow.

Eisenmenger Complex Defintion – the combination of VSD with

pulmonary HTN and consequent R-to-L shunt through the defect, with or without an associated overriding aorta

CXR RV enlargement on lateral projection Enlarged central pulmonary arteries Normal to decreased pulmonary vascular

markings peripherally

Eisenmenger Complex

Which CHDs appear with cyanosis and increased pulmonary blood flow?

These include total anomalous pulmonary venous return, truncus arteriosus, transposition of the great vessels, tricuspid atresia, and single ventricle. Hypoplastic left heart syndrome may appear with CHF and cyanosis.

Major Causes of CHF in newborn Constitutional problems such as anemia,

hypoglycemia, sepsis Primary pump problems such as hypoplastic left

heart Outflow obstructions such as aortic stenosis or

coarctation of the aorta Inflow problems such as cor triatriatum or mitral

valve stenosis Extracardiac shunts such as vein of Galen

malformation or a hemangioendothelioma

Cor triatriatum – a heart with 3 atrial chambers, the LA being subdivided by a transverse septum with a single small opening which seperates the openings of the pulmonary veins from the mitral valve

Coarctation of the Aorta

Pulmonary Atresia and Stenosis

Aberrant R Subclavian

TOF Diagnosis on CXR Cyanotic TOF: boot-shaped heart caused

by an enlarged RV with absence of a radiographic main PA segment

Decreased pulmonary vascular markings (PVM)

Acyanotic TOF and TOF/pulmonary atresia with major aorta pulmonary collateral arteries (MAPCA), normal to increased PVMs

Absent PV, mildly enlarged cardiac silhouette, dilated PAs, hyperinflated lungs

TOFImage #1 shows typical cardiac shape and decreased pulmonary vascularity. Image #2 made after BT shunt surgery shows clips on subclavian artery. Image #3 shows edema in right lung due to overperfusion following shunt surgery.

Glycogen Storage Dis (Pompe)Due to deficiency of acid alpha glucosidase, it is a fatal disease of many organs including the heart. Newborns infants may be well but soon develop muscle atonia, cannot feed and their hearts become enormous. Glycogen accumulates in all organs.

Kartagener’s Syndrome

Marfan SyndromeDilatation of the aortic root may require grafting. The pectus excavatum is probably asymptomatic. The incidental neural crest tumor is probably asymptomatic as well.

Ebstein AnomalyCongenital downward displacement of the tricuspid valve into the right ventricle

References

Alpert MD, Joseph S., Editor. The AHA Clinical Cardiac Consult. Lippincott William & Wilkins. 2001

Pretorius MD, E. Scott and Solomon MD MBA, Jeffrey A. Radiology Secrets. 2nd Ed. Elsevier Inc. 2006.

Stedman’s Medical Dictionary. 27th Ed. Lippincott Williams & Wilkins. 2005.