Fig. 4
MIPs of the three resulting multiparametric images from a 20-min D-WB examination with four 5 min passes from 50 to 70 min post-injection using PBIF. A SUV calculated as the average of all four passes reflecting the total 18FDG signal; B Patlak MRFDG reflecting the metabolic rate of 18FDG, i.e. conversion into 18FDG-6P; C Patlak DVFDG reflecting the distribution volume of free 18FDG. This 85-year-old man was referred for interim evaluation of treatment response after relapse of diffuse large cell lymphoma. SUV images (A), showed regression of nodes on both sides of the diaphragm, but a suspicious newcomer FDG-avid focus was described on the left arm (red arrows), and supplemental localized consolidating radiation treatment was considered. However, further analysis of the Patlak images showed this to be a false-positive finding, as there is no signal on MRFDG images (B), and the presence of signal only on DVFDG images (C) shows this to be unbound FDG. The patient was thus in disease remission and required no supplemental treatment. There were a couple other findings that required investigation. On the right side of the abdomen (black arrow 1) lies a little FDG-avid focus in the colon, in relation to a polyp that on polypectomy showed a high-grade adenoma. There were also bilateral foci in the prostate (black arrows 2). Transrectal ultra-sound could not exclude malignancy, but no biopsy was taken due to the patients' age and comorbidities