Radiolabeled somatostatin (sst) receptor agonists are integral to the diagnosis of gastroenteropancreatic neuroendocrine tumors (NETs), but detection rates, especially of liver metastases, remain limited even with PET/CT. Ga-OPS202 (Ga-NODAGA-JR11; NODAGA = 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid and JR11 = Cpa-c(dCys-Aph(Hor)-dAph(Cbm)-Lys-Thr-Cys)-dTyr-NH)), a novel radiolabeled sst receptor antagonist with a high affinity for the sst receptor, has the potential to perform better than sst receptor agonists. Here, we present the results of the phase II component of a phase I/II study that evaluated the sensitivity of Ga-OPS202, compared with the reference compound,Ga-DOTATOC (an sst receptor agonist), in PET imaging. Patients received a single 150-MBq intravenous injection ofGa-DOTATOC (15 μg of peptide) and 2 single 150-MBq intravenous injections of Ga-OPS202 (15 μg of peptide at visit 1 and 50 μg at visit 2). Whole-body PET/CT acquisitions were performed 1 h after injection on the same calibrated PET/CT scanner. Diagnostic efficacy measures were compared against contrast medium-enhanced CT or MRI as the gold standard. Two independent masked experts read the scans, and both outcomes were combined for analysis. Twelve consecutive patients with low- or intermediate-grade gastroenteropancreatic NETs took part in this prospective study. Image contrast for matched malignant liver lesions was significantly higher for the Ga-OPS202 scans than for theGa-DOTATOC scan: the median of the mean tumor-to-background SUV ratios were significantly higher for 15 and 50 μg of Ga-OPS202 (5.3 and 4.3, with interquartile ranges of 2.9-5.7 and 3.4-6.3 and values of 0.004 and 0.008) than for Ga-DOTATOC (1.9, with an interquartile range of 1.4-2.9). The higher tumor-to-background ratio ofGa-OPS202 resulted not only in a higher detection rate of liver metastases but also in a significantly higher lesion-based overall sensitivity with the antagonist than with Ga-DOTATOC: 94% and 88% for 50 and 15 μg ofGa-OPS202, respectively, and 59% for 15 μg of Ga-DOTATOC ( < 0.001). Positive predictive values for Ga-OPS202 PET/CT andGa-DOTATOC PET/CT were similar (∼98%). There were no significant differences in image contrast, sensitivity, or positive predictive values between the 2 Ga-OPS202 peptide doses, indicating a high reproducibility. Preliminary diagnostic efficacy data from this phase II study indicate that Ga-OPS202 has high sensitivity for the detection of gastroenteropancreatic NETs. Further studies in larger patient populations are warranted.
Background: Endoscopic lung volume reduction with valves is a valid therapeutic option for COPD patients with severe emphysema. The exclusion of interlobar collateral ventilation (CV) is an important predictor of clinical success. Objectives: Recently, a catheter-based endobronchial in vivo measurement system (Chartis, Pulmonx, USA) has become routine in the clinical evaluation of CV status in target lobes, but the criteria for phenotyping CV by Chartis evaluation have not yet been defined. We asked the questions, how many phenotypes can be identified using Chartis, what are the exact criteria to distinguish them, and how do the Chartis phenotypes respond to valve insertionκ Methods: In a retrospective study, 406 Chartis assessments of 166 patients with severe COPD were analyzed. Four Chartis phenotypes, CV positive (CV+), CV negative (CV-), low flow (LF) and low plateau were identified. Fifty-two patients without CV were treated with valves and followed for 3 months. Results: The Chartis phenotypes were discriminated with respect to decline in expiratory peak flow, increase in resistance index and change in total exhaled volume after 1, 2, 3, 4 and 5 min of measurement time (p < 0.0001, ANOVA), and the cutoff criteria were defined accordingly. To examine the application of these phenotyping criteria, students applied them to 100 Chartis assessments, and they demonstrated almost perfect inter- and intraobserver agreements (κ > 0.9). Compared to baseline, CV- and LF patients with ipsilateral CV- lobe showed an improvement in FEV1 (p < 0.05), vital capacity (p < 0.05) and target lobe volume reduction (p < 0.005) after valve insertion. Conclusion: This study describes the most prevalent Chartis phenotypes.
GA-68 DOTATOC PET/CT allows a high detection rate of NET lesions in the context of MEN-1 syndrome as well as influence therapeutic management in nearly up to half of the patients. GA-68 DOTATOC PET/CT should include a CE-CT to improve MEN-associated NET lesion detection.
(68)Ga-DOTATOC PET/CT was considerably cheaper than (111)In-DTPA-octreotide with respect to both material and personnel costs. Furthermore, by using (68)Ga-DOTATOC PET/CT considerably fewer additional examinations were needed reducing the consequential costs significantly.
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