Standardized uptake value in pediatric patients: an investigation to determine the optimum measurement parameter

Abstract.

Although the standardized uptake value (SUV) is currently used in fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging, concerns have been raised over its accuracy and clinical relevance. Dependence of the SUV on body weight has been observed in adults and this should be of concern in the pediatric population, since there are significant body changes during childhood. The aim of the present study was to compare SUV measurements based on body weight, body surface area and lean body mass in the pediatric population and to determine a more reliable parameter across all ages. Sixty-eight pediatric FDG-PET studies were evaluated. Age ranged from 2 to 17 years and weight from 11 to 77 kg. Regions of interest were drawn at the liver for physiologic comparison and at FDG-avid malignant lesions. SUV based on body weight (SUV_bw) varied across different weights, a phenomenon less evident when body surface area (SUV_bsa) normalization is applied. Lean body mass-based SUV (SUV_lbm) also showed a positive correlation with weight, which again was less evident when normalized to bsa (SUV_bsa-lbm). The measured liver SUV_bw was 1.1±0.3, a much lower value than in our adult population (1.9±0.3). The liver SUV_bsa was 7.3±1.3. The tumor sites had an SUV_bw of 4.0±2.7 and an SUV_bsa of 25.9±15.4 (65% of the patients had neuroblastoma). The bsa-based SUVs were more constant across the pediatric ages and were less dependent on body weight than the SUV_bw. These results indicate that SUV calculated on the basis of body surface area is a more uniform parameter than SUV based on body weight in pediatric patients and is probably the most appropriate approach for the follow-up of these patients.