The objective of this study was to compare the diagnostic accuracy of 18F Choline positron emission tomography/computed tomography (PET/CT) static acquisition versus dynamic acquisition in detecting locoregional recurrence in patients subjected to prostatectomy.
99 subjects (mean age 70 ± 7.2, mean PSA 3.86 ± 5.05) treated with radical prostatectomy underwent a PET/CT study for restaging prostate cancer consisting in a dynamic acquisition (dynamic PET/CT) on the prostatic loggia and a whole body acquisition (static PET/CT) according to standard guidelines in the same exam session. A datasheet was generated for separate imaging modality comparison (static vs. dynamic PET/CT). The positive findings detected by each technique were then compared with follow-up data that served as the reference standard. Subjects were then divided in four groups according to results. Agreement among techniques has been studied by means of k statistic.
58 subjects (56%) were considered as negative for local recurrence in both techniques (mean PSA = 3.36± 4.43); 22 (22%) were positive in both modalities (mean PSA = 6.18±6.84); 9 subjects (9%) shown a negative dynamic PET/CT and a positive static PET/CT (mean PSA 1.34±0.46) while 10 subjects (10%) shown a positive dynamic PET/CT and a negative static PET/CT (mean PSA 3.89±4.76). Cohen’s K was equal to 0.56.
Our study shows a moderate concordance between dynamic and static PET/CT. The dynamic acquisition allowed the detection of local recurrence in 10% of the subject with a negative static PET/CT scan.