Adapting CMR sequences for CHD and imaging small patients

In this chapter, the necessary modifications to common cardiovascular magnetic resonance sequences will be discussed. Specific areas that will be covered are: optimization of steady-state free precession cine imaging for the assessment of function, whole heart imaging in infants and children, velocity-encoded phase contrast magnetic resonance for the assessment of flow in paediatrics, and modification of contrast-enhanced magnetic resonance angiographic sequences in childhood. In addition, various methods of dealing with respiratory motion in children will be discussed.

Use of Intracardiac Echocardiography in Cardiac Electrophysiology

Intracardiac echocardiography is increasingly used during invasive electrophysiology procedures. Common applications include guiding transseptal puncture, assessing potential complications, and identifying structures invisible under fluoroscopy. It is important to distinguish intravascular ultrasound from intracardiac ultrasound. Intravascular ultrasound uses high-frequency transducers that provide excellent high-resolution images but have limited tissue penetration. Intracardiac imaging uses lower frequencies, increasing tissue penetration to 14 cm and permitting “whole heart” imaging. The purpose of this brief introduction is to provide practical points of reference for use of intracardiac echocardiography and orientation to the images that follow in the remainder of the book. Thus, only images from the phased-array system are included.