3D CT an Alternative to Catheterization in Neonatal Heart Defect Diagnosis

November 04, 2003

Alicia Ault

Nov. 4, 2003 (New Orleans)    Three-dimensional multislice computed tomography (CT) quickly and effectively identifies extracardiac heart defects in neonates, which should make it the diagnostic tool of choice after echocardiography when preparing for surgery, researchers reported here Sunday at the American Academy of Pediatrics National Conference and Exhibition.

Lead author Russel Hirsch, MD, FAAP, director of the cardiac catheterization lab at the Heart Center of Cincinnati Children's Hospital, reported on 13 patients. Mean age was 11 days, and mean weight was 3 kg. All were neonates who had undergone echocardiography, but, for various reasons, surgeons were unable to make a diagnosis, Dr. Hirsch told meeting attendees.

The patients had been referred for cardiac catheterization for definitive diagnosis before surgery, but instead were given CT with a mean duration of six seconds. All patients were given contrast enhancement (Optiray 350) via hand injection. Only five patients required any sedation, and none were intubated.

The images produced could be manipulated 360° for views from every angle.

"Extracardiac anatomy was defined rapidly, without complications in all cases," Dr. Hirsch said. Abnormalities identified included hypoplastic left heart syndrome, truncus arteriosus, single ventricle with anomalous pulmonary venous return, and interrupted aortic arch. All of the diagnoses were confirmed at surgery, said Dr. Hirsch.

He concluded, "Multislice 3D CT should be considered the imaging procedure of choice in the neonatal population with congenital heart defects if noninvasive diagnostic evaluations are inconclusive; hemodynamic assessment is not required; and therapeutic intervention is not an option."

Some in the audience questioned whether these neonates should have undergone magnetic resonance imaging instead, because CT results in radiation exposure. But Dr. Hirsch said the infants he studied were generally very ill and might not have survived the general anesthesia and hour needed to complete an MRI scan.

Also, he noted that radiation exposure from the short CT scan was likely to be less than that received during a cardiac catheterization. During that procedure, adults generally are exposed to 299 mrem; a 15-second CT scan in adults results in a 300-mrem exposure, said Dr. Hirsch.

Session moderator Thomas Klitzner, MD, PhD, FAAP, from the Mattel Children's Hospital at the University of California, Los Angeles, called Dr. Hirsch's study "a major accomplishment" in an interview with Medscape. Especially impressive was the ability to scan the children without sedation or intubation, he said, noting that neonates with defects tend to be quite ill.

"They were able to identify all the important surgical aspects of the disease, which is especially important when you need to go quickly into surgery," he told Medscape.

Dr. Klitzner said he thought it would be a challenge for magnetic resonance imaging to do as well in these small, sick patients. When asked if he thought this study would lead to wider use of CT as a diagnostic tool, he said, "I hope so."

AAP 2003 National Conference and Exhibition: Abstract 510. Presented Nov. 2, 2003.

Pediatr Cardiol. 2003;24:613-633

Reviewed by Gary D. Vogin, MD

Alicia Ault is a freelance writer for Medscape.


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