The front line in the diagnosis of abnormalities of pulmonary veins is echocardiography. However, due to limited acoustic windows, further studies are needed. Until recently, catheterisation was thought as the gold standard as both anatomical and functional information could be provided. However, the total examination and exposure time as well as the interventional nature of the method together with the recent technological advances of the MR and CT systems, have led to almost complete replacement of catheterization by non-invasive imaging methods.
In our institution, a tertiary referral centre for heart disease, in close co-operation with the cardiologists and the cardiac surgeons of the neonatal-pediatric clinic we have decided that the front line imaging methods are a thorough echocardiogram followed by a CT angiogram. With these two examinations, a thorough and detailed diagnosis of the cardiac-vascular abnormality can be obtained within a few hours from the admission of the infant. Functional information together with 3D reformatting provide all the information needed for decision making and surgery planning.
All patients, independent of age, have initially an echocardiogram by a highly experienced pediatric cardiologist and, immediately afterwards, are received at the CT unit.
EXAMINATION PROTOCOLS
All examinations were performed with a SIEMENS Dual Source SOMATOM DEFINITION SYSTEM
The protocols used depend on the age of the patient.
A. Young patients up to 3 yrs old
Scan parameters
Patient Position: cranial/caudal - supine
Normal breathing
Scan delay: 2 sec
80 kV
80-150 mAs (no care 4D)
Slice thickness: 2.0 mm (Acq 64x0,6mm)
Pitch: 1.4
Rotation time: 0.5sec
Reconstruction parameters
Slice thick. 1,0mm Kernel B20f smooth
Increment 1.0mm Window Baby Abdomen
Injection parameters
Injection route: Preferably through the femoral or axillary veins
Contrast medium: 2ml/kg of LOCM ( concentration 270 - 320mg) followed by 30mls of saline flash
The injection is performed manually when the patient's weight is under 6 kgs. When the patient's weight is above 6 kgs, an injector is used with a flow rate 3 - 4 mls/sec
The scan is performed 25 secs after the injection has finished
B. Patients above 3 yrs old
Scan parameters
Patient Position: cranial/caudal - supine (heart)
Scan delay: 7 sec
120 kV
mAs care 4D
Slice thickness 3.0mm (Acq 64x0,6mm)
Pitch 0.2 – 0.3
Rot. time 0.33sec
ROI Left atrium (HU 100)
Reconstruction parameters
Slice thick. 0,75mm Kernel B20f smooth
Increment 0,4mm Window Cardiac
Injection parameters
Injection route: Preferably through the right antecubital vein
Contrast medium 2ml/kg in case of children or 110mls in adults of LOCM (concentration 320 - 370mls)
Flow/rate 4-5ml/sec
Saline flash 30ml - 3ml/sec