TY - JOUR
T1 - Quantitative Assessments of Tumor Activity in a General Oncologic PET/CT Population
T2 - Which Metric Minimizes Tracer Uptake Time Dependence?
AU - Ince, Semra
AU - Laforest, Richard
AU - Itani, Malak
AU - Prasad, Vikas
AU - Derenoncourt, Paul Robert
AU - Crandall, John P.
AU - Ashrafinia, Saeed
AU - Smith, Anne M.
AU - Wahl, Richard
AU - Fraum, Tyler J.
N1 - Publisher Copyright:
COPYRIGHT © 2024 by the Society of Nuclear Medicine and Molecular Imaging.
PY - 2024/9/1
Y1 - 2024/9/1
N2 - In oncologic PET, the SUV and standardized uptake ratio (SUR) of a viable tumor generally increase during the postinjection period. In contrast, the net influx rate (Ki), which is derived from dynamic PET data, should remain relatively constant. Uptake-time-corrected SUV (cSUV) and SUR (cSUR) have been proposed as uptake-time-independent, static alternatives to Ki. Our primary aim was to quantify the intrascan repeatability of Ki, SUV, cSUV, SUR, and cSUR among malignant lesions on PET/CT. An exploratory aim was to assess the ability of cSUR to estimate Ki. Methods: This prospective, single-center study enrolled adults undergoing standard-of-care oncologic PET/CT. SUV and Ki images were reconstructed from dynamic PET data obtained before (~35–50 min after injection) and after (~75–90 min after injection) standard-of-care imaging. Tumors were manually segmented. Quantitative metrics were extracted. cSUVs and cSURs were calculated for a 60-min postinjection reference uptake time. The magnitude of the intrascan test–retest percent change (test–retest j%Dj) was calculated. Coefficients of determination (R2) and intraclass correlation coefficients (ICC) were also computed. Differences between metrics were assessed via the Wilcoxon signed-rank test (a, 0.05). Results: This study enrolled 78 subjects; 41 subjects (mean age, 63.8 y; 24 men) with 116 lesions were analyzed. For both tracers, SUVmax and maximum SUR (SURmax) had large early-to-late increases (i.e., poor intrascan repeatability). Among [18F]FDG-avid lesions (n 5 93), there were no differences in intrascan repeatability (median test–retest j%Dj; ICC) between the maximum Ki (Ki,max) (13%; 0.97) and either the maximum cSUV (cSUVmax) (12%, P 5 0.90; 0.96) or the maximum cSUR (cSURmax) (13%, P 5 0.67; 0.94). For DOTATATE-avid lesions (n 5 23), there were no differences in intrascan repeatability between the Ki,max (11%; 0.98) and either the cSUVmax (13%, P 5 0.41; 0.98) or the cSURmax (11%, P 5 0.08; 0.94). The SUVmax, cSUVmax, SURmax, and cSURmax were all strongly correlated with the Ki,max for both [18F]FDG (R2, 0.81–0.92) and DOTATATE (R2, 0.88–0.96), but the cSURmax provided the best agreement with the Ki,max across early-to-late time points for [18F]FDG (ICC, 0.69–0.75) and DOTATATE (ICC, 0.90–0.91). Conclusion: Ki,max, cSUVmax, and cSURmax had low uptake time dependence compared with SUVmax and SURmax.
AB - In oncologic PET, the SUV and standardized uptake ratio (SUR) of a viable tumor generally increase during the postinjection period. In contrast, the net influx rate (Ki), which is derived from dynamic PET data, should remain relatively constant. Uptake-time-corrected SUV (cSUV) and SUR (cSUR) have been proposed as uptake-time-independent, static alternatives to Ki. Our primary aim was to quantify the intrascan repeatability of Ki, SUV, cSUV, SUR, and cSUR among malignant lesions on PET/CT. An exploratory aim was to assess the ability of cSUR to estimate Ki. Methods: This prospective, single-center study enrolled adults undergoing standard-of-care oncologic PET/CT. SUV and Ki images were reconstructed from dynamic PET data obtained before (~35–50 min after injection) and after (~75–90 min after injection) standard-of-care imaging. Tumors were manually segmented. Quantitative metrics were extracted. cSUVs and cSURs were calculated for a 60-min postinjection reference uptake time. The magnitude of the intrascan test–retest percent change (test–retest j%Dj) was calculated. Coefficients of determination (R2) and intraclass correlation coefficients (ICC) were also computed. Differences between metrics were assessed via the Wilcoxon signed-rank test (a, 0.05). Results: This study enrolled 78 subjects; 41 subjects (mean age, 63.8 y; 24 men) with 116 lesions were analyzed. For both tracers, SUVmax and maximum SUR (SURmax) had large early-to-late increases (i.e., poor intrascan repeatability). Among [18F]FDG-avid lesions (n 5 93), there were no differences in intrascan repeatability (median test–retest j%Dj; ICC) between the maximum Ki (Ki,max) (13%; 0.97) and either the maximum cSUV (cSUVmax) (12%, P 5 0.90; 0.96) or the maximum cSUR (cSURmax) (13%, P 5 0.67; 0.94). For DOTATATE-avid lesions (n 5 23), there were no differences in intrascan repeatability between the Ki,max (11%; 0.98) and either the cSUVmax (13%, P 5 0.41; 0.98) or the cSURmax (11%, P 5 0.08; 0.94). The SUVmax, cSUVmax, SURmax, and cSURmax were all strongly correlated with the Ki,max for both [18F]FDG (R2, 0.81–0.92) and DOTATATE (R2, 0.88–0.96), but the cSURmax provided the best agreement with the Ki,max across early-to-late time points for [18F]FDG (ICC, 0.69–0.75) and DOTATATE (ICC, 0.90–0.91). Conclusion: Ki,max, cSUVmax, and cSURmax had low uptake time dependence compared with SUVmax and SURmax.
KW - corrected SUV
KW - metabolic rate
KW - Patlak slope
KW - PET
UR - http://www.scopus.com/inward/record.url?scp=85203300729&partnerID=8YFLogxK
U2 - 10.2967/jnumed.123.266469
DO - 10.2967/jnumed.123.266469
M3 - Article
C2 - 39142828
AN - SCOPUS:85203300729
SN - 0161-5505
VL - 65
SP - 1349
EP - 1356
JO - Journal of Nuclear Medicine
JF - Journal of Nuclear Medicine
IS - 9
ER -