Early Assessment of Treatment Response in Takayasu Arteritis: An 18FDG PET Procedure.
OBJECTIVE
To describe a procedure allowing early assessment of treatment response in Takayasu arteritis (TA) patients by averaging the standard uptake value obtained from N hottest voxels irrespective of their location within the F-FDG-positive vessel walls (SUVmax-N).


METHODS
The procedure is illustrated in a score-V TA patient before and after 1 and 3 months of glucocorticoid treatment (scans 0-1-3, respectively). Comparison between scans was made by using SUVmax-N repeatability percentages with 95-99-99.9% reliability.


RESULTS
No significant difference in SUVmax (ie, N = 1) was found between scan 0 and 1, and between scan 1 and 3, with 95% reliability. A significant difference in SUVmax-N was found with 99.9% reliability for each scan pair by averaging N = 4100-515 hottest voxels (total hottest volume of 100.0-12.6 mL), respectively.


CONCLUSIONS
The proposed SUVmax-N procedure may be an efficient tool to early assess treatment response in TA patients. Further studies involving series of patients with large vessel vasculitis are warranted to investigate its usefulness in their management.
From the *CH de Libourne, Service de Médecine Interne, Libourne; †CHU de Bordeaux, Service de Médecine Nucléaire, Pessac; ‡Univ Bordeaux, Centre de Recherche Cardio-Thoracique, F-33076 Bordeaux; and §INSERM U 1045, Centre de Recherche Cardio-Thoracique, Bordeaux, France.
Olivier
O
Caubet
Vincent
V
Meunier
Roger
R
Marthan
Eric
E
Laffon
D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013625:Takayasu Arteritis / Q000000981:diagnostic imaging* / Q000188:drug therapy
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18