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Frankfurt am Main, Germany

Luboldt W.,Multiorgan Screening Foundation | Luboldt W.,University Hospital Frankfurt | Hartmann H.,Multiorgan Screening Foundation | Wiedemann B.,Multiorgan Screening Foundation | And 2 more authors.
Molecular Imaging | Year: 2010

The purpose of this study was to standardize therapy monitoring of hepatic metastases from gastroenteropancreatic neuroendocrine tumors (GEP-NETs) during the course of somatostatin receptor radionuclide therapy (SRRT). In 21 consecutive patients with nonresectable hepatic metastases of GEP-NETs, chromogranin A (CgA) and 68Ga-DOTATOC PET/CT were compared before and after the last SRRT. On 68Ga-DOTATOC PET/CT, the maximum standard uptake values (SUVmax) of normal liver and hepatic metastases were calculated. In addition, the volumes of hepatic metastases (volume of interest [VOI]) were measured using four cutoffs to separate normal liver tissue from metastases (SUVmax of the normal liver plus 10% [VOI liver+10%], 20% [VOIliver+20%], 30% [VOI liver+30%] and SUV = 10 [VOI10SUV]). The SUVmax of the normal liver was below 10 (7.2 ± 1.3) in all patients and without significant changes. Overall therapy changes (Δ) per patient (mean [95% CI]) were statistically significant with p < .01 for DCgA 5 243 (269 to 217), ΔSUVmax 5222 (229 to214), and ΔVOI10SUV=-53 (268 to 238)% and significant with p < .05 for ΔVOI liver+10%5229 (255 to 23)%, ΔVOIliver+20% 5 232 (262 to 22) and ΔVOIliver+30% 5 237 (266 to 28). Correlations were found only between DCgA and Delta;VOI10SUV (r 5 .595; p < .01), ΔSUVmax and ΔVOI10SUV (0.629, p < .01), and SUVmax and ΔSUVmax (r52.446; p < .05). 68 Ga-DOTATOC PET/CT allows volumetric therapy monitoring via an SUV-based cut-off separating hepatic metastases from normal liver tissue (10 SUV recommended). © 2010 Decker Publishing. Source

Luboldt W.,Multiorgan Screening Foundation | Luboldt W.,University Hospital Frankfurt | Volker T.,University Hospital Dresden | Wiedemann B.,University Hospital Dresden | And 12 more authors.
European Radiology | Year: 2010

Objective: To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas ≥10mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off. Methods: 84 patients, who underwent PET/CT and colonoscopy (n=79)/sigmoidoscopy (n=5) for (79 × 6 + 5 × 2) = 484 colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting masspositive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrastenhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs. Results: Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n=23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n=10) the SUVmax was ≥5. This cutoff resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV max. Conclusion: FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUVmax≥5 improves the accuracy. © The Author(s) 2010. Source

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