What and how should we measure in paediatric oncology FDG-PET/CT? Comparison of commonly used SUV metrics for differentiation between paediatric tumours

Abstract

Background: In clinical routine, SUV max and SUV peak are most often used to determine the glucose metabolism in tumours by 18 F-FDG PET/CT. Both metrics can be further normalised to SUVs in reference regions resulting in a SUV ratio (SUV ratio ). The aim of the study was to directly compare several widely used SUVs/SUV ratios with regard to differentiation between common tumours in paediatric patients; a special focus was put on characteristics of reference region SUVs.Methods: The final study population consisted of 61 children and adolescents with diagnoses of non-Hodgkin lymphoma (NHL, n = 25), Hodgkin lymphoma (HL, n = 14), and sarcoma (n = 22). SUV metrics included SUV max and SUV peak as well as both parameters normalised to liver and mediastinal blood pool, respectively, yielding the SUV ratios SUV max/liver , SUV max/mediastinum , SUV peak/liver , and SUV peak/mediastinum . Results: The metrics SUV max , SUV peak , SUV max/liver , and SUV peak/liver all proved to be sensitive for tumour differentiation (p ≤ 0.008); in contrast, SUV max/mediastinum and SUV peak/mediastinum revealed to be non-sensitive approaches. Correlation analyses showed inverse associations between reference region SUVs and SUV ratios (p < 0.05). Multiple regression analyses demonstrated significant effects of factors as bodyweight and uptake time on reference region SUVs (p < 0.01), and thus indirectly on the corresponding SUV ratios . Conclusions: In the paediatric population, the ability to differentiate between common tumours remarkably varies between SUV metrics. When using SUV ratios , the choice of reference region is crucial. Factors potentially influencing reference region SUVs (and thus SUV ratios ) should be taken into account in order to avoid erroneous conclusions. When not possible, SUV max and SUV peak represent less complex, more robust alternatives.

Are Semiquantitative Methods Superior to Deauville Scoring in the Monitoring Therapy Response for Pediatric Hodgkin Lymphoma?

“…However, it is known that SUV measurements can be affected by several factors that may result in considerable variations of accuracy and reproducibility, including alterations in the calibration of the PET scanner or dose calibrator, tracer extravasation at the injection site, elevated blood glucose levels or patient motion (leading to SUV measurement errors up to 50%) and the partial volume effect (which may lead to SUV underestimation in smaller tumors). It has been found that both liver and mediastinal blood pool SUV could be predicted by patient weight [ 11 , 28 , 29 ]. Malladi et al showed that liver SUV was affected by gender, whereas mediastinal SUV was dependent on the uptake time [ 21 ].…”

Are Semiquantitative Methods Superior to Deauville Scoring in Monitoring Therapy Response of Pediatric Hodgkin Lymphoma?

“…Based on our findings, we recommend that pediatric patients with SUVmax higher than 15.5g/ml at baseline 18 F-FDG PET-CT should undergo a stricter follow-up. However, it is known that SUV measurements can be affected by several factors that may result in considerable variations of accuracy and reproducibility, including alterations in the calibration of the PET scanner or dose calibrator, tracer extravasation at the injection site, elevated blood glucose levels or patient motion (leading to SUV measurement errors up to 50%), and partial volume effect (which may lead to SUV underestimation in smaller tumors) [11,[26][27]. Additional studies with a larger sample size should be conducted to corroborate our findings.…”

“…It has been found that liver and mediastinal blood pool SUVs were both predicted by patient weight [31]. Malladi et al proved that liver SUV was affected by gender, whereas mediastinal SUV was dependent on the uptake time [36].…”

Positron Emission Tomography for Response Evaluation in Microenvironment-Targeted Anti-Cancer Therapy

“…Standardized uptake value (SUV) is a normalized measure of radiotracer uptake, defined as the ratio of the radioactivity concentration in a defined region (MBq/mL) to the injected radioactivity that is corrected for total body mass (MBq/g). The maximal values of SUV, expressed as SUVmax and SUVpeak, are used for evaluating tumor aggressiveness and as prognostic markers of the tumor [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. SUV is a standard measure in FDG-PET which is representative of tumor viability and aggressiveness.…”