ASNC: Cardiac PET Shows Promise for Evaluating Children with Congenital Anomalies

SAN DIEGO, Sept. 14 -- Cardiac PET imaging offers a safe, accurate, noninvasive method for monitoring the expanding population of long-term survivors of congenital anomalies, according to a small clinical series reported here.

Confirmatory coronary angiography showed that PET correctly identified ischemia in four of six patients and had a 100% specificity for ruling out ischemia, Adnan K. Chhatriwalla, M.D., of the Cleveland Clinic, reported at the American Society of Nuclear Cardiology meeting.

"Cardiac PET imaging is a promising option for noninvasive assessment of myocardial ischemia in children with complex congenital heart disease," said Dr. Chhiatriwalla. "PET also offers advantages over other noninvasive tests."

"However," he added, "the high pretest probability [of ischemia] in our population might have skewed the results, and the findings from this small sample require validation in a larger series."

The need for long-term monitoring of children with congenital heart disorders has increased as more patients achieve long-term survival. Several options for noninvasive imaging of myocardial perfusion are available, but no standards for using the modalities exist.

"Cardiac PET testing with rubidium-82 offers several advantages in the pediatric population, including better spatial resolution in small hearts and shorter acquisition times," said Dr. Chhiatriwalla.

Dr. Chhiatriwalla and colleagues evaluated myocardial perfusion imaging with Rb-82 PET in 22 consecutive pediatric patients with various complex congenital anomalies. PET images were reviewed by two blinded observers, who assigned myocardial perfusion scores based on a standard 17-segment model. When available, coronary angiograms were read by a blinded observer.

The patients ranged in age from eight months to 18 years, and their weight ranged from 5.4 to 104.6 kg. PET imaging indicated coronary ischemia in eight of the 22 patients, 15 of whom underwent cardiac catheterization.

Comparison of angiographic and PET imaging results showed that PET correctly identified ischemia in four of six patients and correctly ruled out ischemia in all nine patients who had both PET and angiographic imaging. PET performance characteristics were:

• Sensitivity 100%
• Specificity 82%
• Negative predictive value 100%
• Positive predictive value 67%

"We plan to continue evaluating PET's accuracy for identifying myocardial ischemia in patients with complex congenital anomalies," said Dr. Chhiatriwalla.