@article{ChenWernerLapaetal.2018, author = {Chen, Xinyu and Werner, Rudolf A. and Lapa, Constantin and Nose, Naoko and Hirano, Mitsuru and Javadi, Mehrbod S. and Robinson, Simon and Higuchi, Takahiro}, title = {Subcellular storage and release mode of the novel \(^{18}\)F-labeled sympathetic nerve PET tracer LMI1195}, series = {EJNMMI Research}, volume = {8}, journal = {EJNMMI Research}, number = {12}, issn = {2191-219X}, doi = {10.1186/s13550-018-0365-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167081}, year = {2018}, abstract = {Background: \(^{18}\)F-N-[3-bromo-4-(3-fluoro-propoxy)-benzyl]-guanidine (\(^{18}\)F-LMI1195) is a new class of PET tracer designed for sympathetic nervous imaging of the heart. The favorable image quality with high and specific neural uptake has been previously demonstrated in animals and humans, but intracellular behavior is not yet fully understood. The aim of the present study is to verify whether it is taken up in storage vesicles and released in company with vesicle turnover. Results: Both vesicle-rich (PC12) and vesicle-poor (SK-N-SH) norepinephrine-expressing cell lines were used for in vitro tracer uptake studies. After 2 h of \(^{18}\)F-LMI1195 preloading into both cell lines, effects of stimulants for storage vesicle turnover (high concentration KCl (100 mM) or reserpine treatment) were measured at 10, 20, and 30 min. \(^{131}\)I-meta-iodobenzylguanidine (\(^{131}\)I-MIBG) served as a reference. Both high concentration KCl and reserpine enhanced \(^{18}\)F-LMI1195 washout from PC12 cells, while tracer retention remained stable in the SK-N-SH cells. After 30 min of treatment, 18F-LMI1195 releasing index (percentage of tracer released from cells) from vesicle-rich PC12 cells achieved significant differences compared to cells without treatment condition. In contrast, such effect could not be observed using vesicle-poor SK-N-SH cell lines. Similar tracer kinetics after KCl or reserpine treatment were also observed using 131I-MIBG. In case of KCl exposure, Ca\(^{2+}\)-free buffer with the calcium chelator, ethylenediaminetetracetic acid (EDTA), could suppress the tracer washout from PC12 cells. This finding is consistent with the tracer release being mediated by Ca\(^{2+}\) influx resulting from membrane depolarization. Conclusions: Analogous to \(^{131}\)I-MIBG, the current in vitro tracer uptake study confirmed that \(^{131}\)F-LMI1195 is also stored in vesicles in PC12 cells and released along with vesicle turnover. Understanding the basic kinetics of \(^{18}\)FLMI1195 at a subcellular level is important for the design of clinical imaging protocols and imaging interpretation.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @article{WernerBundschuhBundschuhetal.2018, author = {Werner, Rudolf A. and Bundschuh, Ralph A. and Bundschuh, Lena and Javadi, Mehrbod S. and Higuchi, Takahiro and Weich, Alexander and Sheikhbahaei, Sara and Pienta, Kenneth J. and Buck, Andreas K. and Pomper, Martin G. and Gorin, Michael A. and Lapa, Constantin and Rowe, Steven P.}, title = {MI-RADS: Molecular Imaging Reporting and Data Systems - A Generalizable Framework for Targeted Radiotracers with Theranostic Implications}, series = {Annals of Nuclear Medicine}, journal = {Annals of Nuclear Medicine}, issn = {0914-7187}, doi = {10.1007/s12149-018-1291-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166995}, year = {2018}, abstract = {Both prostate-specific membrane antigen (PSMA)- and somatostatin receptor (SSTR)-targeted positron emission tomography (PET) imaging agents for staging and restaging of prostate carcinoma or neuroendocrine tumors, respectively, are seeing rapidly expanding use. In addition to diagnostic applications, both classes of radiotracers can be used to triage patients for theranostic endoradiotherapy. While interpreting PSMA- or SSTR-targeted PET/computed tomography (CT) scans, the reader has to be aware of certain pitfalls. Adding to the complexity of the interpretation of those imaging agents, both normal biodistribution, and also false-positive and -negative findings differ between PSMA- and SSTR-targeted PET radiotracers. Herein summarized under the umbrella term molecular imaging reporting and data systems (MI-RADS), two novel RADS classifications for PSMA- and SSTR-targeted PET imaging are described (PSMA- and SSTR-RADS). Both framework systems may contribute to increase the level of a reader's confidence and to navigate the imaging interpreter through indeterminate lesions, so that appropriate workup for equivocal findings can be pursued. Notably, PSMA- and SSTR-RADS are structured in a reciprocal fashion, i.e. if the reader is familiar with one system, the other system can readily be applied as well. In the present review we will discuss the most common pitfalls on PSMA- and SSTR-targeted PET/CT, briefly introduce PSMA- and SSTR-RADS, and define a future role of the umbrella framework MI-RADS compared to other harmonization systems.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @unpublished{WernerBundschuhBundschuhetal.2018, author = {Werner, Rudolf A. and Bundschuh, Ralph A. and Bundschuh, Lena and Javadi, Mehrbod S. and Leal, Jeffrey P. and Higuchi, Takahiro and Pienta, Kenneth J. and Buck, Andreas K. and Pomper, Martin G. and Gorin, Michael A. and Lapa, Constantin and Rowe, Steven P.}, title = {Interobserver Agreement for the Standardized Reporting System PSMA-RADS 1.0 on \(^{18}\)F-DCFPyL PET/CT Imaging}, series = {Journal of Nuclear Medicine}, journal = {Journal of Nuclear Medicine}, issn = {0161-5505}, doi = {10.2967/jnumed.118.217588}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167788}, year = {2018}, abstract = {Objectives: Recently, the standardized reporting and data system for prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging studies, termed PSMA-RADS version 1.0, was introduced. We aimed to determine the interobserver agreement for applying PSMA-RADS to imaging interpretation of 18F-DCFPyL PET examinations in a prospective setting mimicking the typical clinical work-flow at a prostate cancer referral center. Methods: Four readers (two experienced readers (ER, > 3 years of PSMA-targeted PET interpretation experience) and two inexperienced readers (IR, < 1 year of experience)), who had all read the initial publication on PSMA-RADS 1.0, assessed 50 18F-DCFPyL PET/computed tomography (CT) studies independently. Per scan, a maximum of 5 target lesions were selected by the observers and a PSMA-RADS score for every target lesion was recorded. No specific pre-existing conditions were placed on the selection of the target lesions, although PSMA-RADS 1.0 suggests that readers focus on the most highly avid or largest lesions. An overall scan impression based on PSMA-RADS was indicated and interobserver agreement rates on a target lesion-based, on an organ-based, and on an overall PSMA-RADS score-based level were computed. Results: The number of target lesions identified by each observer were as follows: ER 1, 123; ER 2, 134; IR 1, 123; and IR 2, 120. Among those selected target lesions, 125 were chosen by at least two individual observers (all four readers selected the same target lesion in 58/125 (46.4\%) instances, three readers in 40/125 (32\%) and two observers in 27/125 (21.6\%) instances). The interobserver agreement for PSMA-RADS scoring among identical target lesions was good (intraclass correlation coefficient (ICC) for four, three and two identical target lesions, ≥0.60, respectively). For lymph nodes, an excellent interobserver agreement was derived (ICC=0.79). The interobserver agreement for an overall scan impression based on PSMA-RADS was also excellent (ICC=0.84), with a significant difference for ER (ICC=0.97) vs. IR (ICC=0.74, P=0.005). Conclusions: PSMA-RADS demonstrates a high concordance rate in this study, even among readers with different levels of experience. This suggests that PSMA-RADS can be effectively used for communication with clinicians and can be implemented in the collection of data for large prospective trials.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @article{WernerBundschuhHiguchietal.2018, author = {Werner, Rudolf A. and Bundschuh, Ralph A. and Higuchi, Takahiro and Javadi, Mehrbod S. and Rowe, Steven P. and Zs{\´o}t{\´e}r, Norbert and Kroiss, Matthias and Fassnacht, Martin and Buck, Andreas K. and Kreissl, Michael C. and Lapa, Constantin}, title = {Volumetric and Texture Analysis of Pretherapeutic \(^{18}\)F-FDG PET can Predict Overall Survival in Medullary Thyroid Cancer Patients Treated with Vandetanib}, series = {Endocrine}, journal = {Endocrine}, issn = {1355-008X}, doi = {10.1007/s12020-018-1749-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167910}, year = {2018}, abstract = {Purpose: The metabolically most active lesion in 2-deoxy-2-(\(^{18}\)F)fluoro-D-glucose (\(^{18}\)F-FDG) PET/CT can predict progression-free survival (PFS) in patients with medullary thyroid carcinoma (MTC) starting treatment with the tyrosine kinase inhibitor (TKI) vandetanib. However, this metric failed in overall survival (OS) prediction. In the present proof of concept study, we aimed to explore the prognostic value of intratumoral textural features (TF) as well as volumetric parameters (total lesion glycolysis, TLG) derived by pre-therapeutic \(^{18}\)F-FDG PET. Methods: Eighteen patients with progressive MTC underwent baseline \(^{18}\)F-FDG PET/CT prior to and 3 months after vandetanib initiation. By manual segmentation of the tumor burden at baseline and follow-up PET, intratumoral TF and TLG were computed. The ability of TLG, imaging-based TF, and clinical parameters (including age, tumor marker doubling times, prior therapies and RET (rearranged during transfection) mutational status) for prediction of both PFS and OS were evaluated. Results: The TF Complexity and the volumetric parameter TLG obtained at baseline prior to TKI initiation successfully differentiated between low- and high-risk patients. Complexity allocated 10/18 patients to the high-risk group with an OS of 3.3y (vs. low-risk group, OS=5.3y, 8/18, AUC=0.78, P=0.03). Baseline TLG designated 11/18 patients to the high-risk group (OS=3.5y vs. low-risk group, OS=5y, 7/18, AUC=0.83, P=0.005). The Hazard Ratio for cancer-related death was 6.1 for Complexity (TLG, 9.5). Among investigated clinical parameters, the age at initiation of TKI treatment reached significance for PFS prediction (P=0.02, OS, n.s.). Conclusions: The TF Complexity and the volumetric parameter TLG are both independent parameters for OS prediction.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @inproceedings{WernerChenHiranoetal.2018, author = {Werner, Rudolf A. and Chen, Xinyu and Hirano, Mitsuru and Nose, Naoko and Lapa, Constantin and Javadi, Mehrbod S. and Higuchi, Takahiro}, title = {The Impact of Ageing on [\(^{11}\)C]meta-Hydroxyephedrine Uptake in the Rat Heart}, series = {Journal of Nuclear Medicine}, volume = {59}, booktitle = {Journal of Nuclear Medicine}, number = {Supplement No 1}, issn = {0161-5505}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-162228}, pages = {100}, year = {2018}, abstract = {No abstract available.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @article{WernerChenHiranoetal.2018, author = {Werner, Rudolf A. and Chen, Xinyu and Hirano, Mitsuru and Rowe, Steven P. and Lapa, Constantin and Javadi, Mehrbod S. and Higuchi, Takahiro}, title = {SPECT vs. PET in Cardiac Innervation Imaging: Clash of the Titans}, series = {Clinical and Translational Imaging}, journal = {Clinical and Translational Imaging}, issn = {2281-5872}, doi = {10.1007/s40336-018-0289-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-163628}, year = {2018}, abstract = {Purpose: We aim to provide an overview of the conventional single photon emission computed tomography (SPECT) and emerging positron emission tomography (PET) catecholamine analogue tracers for assessing myocardial nerve integrity, in particular focusing on \(^{18}\)F-labeled tracers. Results: Increasingly, the cardiac sympathetic nervous system (SNS) is being studied by non-invasive molecular imaging approaches. Forming the backbone of myocardial SNS imaging, the norepinephrine (NE) transporter at the sympathetic nerve terminal plays a crucial role for visualizing denervated myocardium: in particular, the single-photon-emitting NE analogue \(^{123}\)I-meta-Iodobenzylguanidine (\(^{123}\)I-mIBG) has demonstrated favorable results in the identification of patients at a high risk for cardiac death. However, cardiac neuronal PET agents offer several advantages inlcuding improved spatio-temporal resolution and intrinsic quantifiability. Compared to their \(^{11}\)C-labeled counterparts with a short half-life (20.4 min), novel \(^{18}\)F-labeled PET imaging agents to assess myocardial nerve integrity have the potential to revolutionize the field of SNS molecular imaging: The longer half-life of \(^{18}\)F (109.8 min) allows for more flexibility in the study design and delivery from central cyclotron facilities to smaller hospitals may lead to further cost reduction. A great deal of progress has been made by the first in-human studies of such \(^{18}\)F-labeled SNS imaging agents. Moreover, dedicated animal platforms open avenues for further insights into the handling of radiolabeled catecholamine analogues at the sympathetic nerve terminal. Conclusions: \(^{18}\)F-labeled imaging agents demonstrate key properties for mapping cardiac sympathetic nerve integrity and might outperform current SPECT-based or \(^{11}\)C-labeled tracers in the long run.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @article{WernerChenMayaetal.2018, author = {Werner, Rudolf A. and Chen, Xinyu and Maya, Yoshifumi and Eissler, Christoph and Hirano, Mitsuru and Nose, Naoko and Wakabayashi, Hiroshi and Lapa, Constantin and Javadi, Mehrbod S. and Higuchi, Takahiro}, title = {The Impact of Ageing on 11C-Hydroxyephedrine Uptake in the Rat Heart}, series = {Scientific Reports}, volume = {8}, journal = {Scientific Reports}, number = {11120}, issn = {2281-5872}, doi = {10.1038/s41598-018-29509-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164826}, year = {2018}, abstract = {We aimed to explore the impact of ageing on 11C-Hydroxyephedrine (11C-HED) uptake in the healthy rat heart in a longitudinal setting. To investigate a potential cold mass effect, the influence of specific activity on cardiac 11C-HED uptake was evaluated: 11C-HED was synthesized by N-methylation of (-)-metaraminol as the free base (radiochemical purity >95\%) and a wide range of specific activities (0.2-141.9 GBq/μmol) were prepared. \(^{11}\)C-HED (48.7±9.7MBq, ranged 0.2-60.4μg/kg cold mass) was injected in healthy Wistar Rats. Dynamic 23-frame PET images were obtained over 30 min. Time activity curves were generated for the blood input function and myocardial tissue. Cardiac 11C-HED retention index (\%/min) was calculated as myocardial tissue activity at 20-30 min divided by the integral of the blood activity curves. Additionally, the impact of ageing on myocardial 11CHED uptake was investigated longitudinally by PET studies at different ages of healthy Wistar Rats. A dose-dependent reduction of cardiac 11C-HED uptake was observed: The estimated retention index as a marker of norepinephrine function decreased at a lower specific activity (higher amount of cold mass). This observed high affinity of 11C-HED to the neural norepinephrine transporter triggered a subsequent study: In a longitudinal setting, the 11C-HED retention index decreased with increasing age. An age-related decline of cardiac sympathetic innervation could be demonstrated. The herein observed cold mass effect might increase in succeeding scans and therefore, 11C-HED microPET studies should be planned with extreme caution if one single radiosynthesis is scheduled for multiple animals.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @unpublished{WernerIlhanLehneretal.2018, author = {Werner, Rudolf A. and Ilhan, Harun and Lehner, Sebastian and Papp, L{\´a}szl{\´o} and Zs{\´o}t{\´e}r, Norbert and Schatka, Imke and Muegge, Dirk O. and Javadi, Mehrbod S. and Higuchi, Takahiro and Buck, Andreas K. and Bartenstein, Peter and Bengel, Frank and Essler, Markus and Lapa, Constantin and Bundschuh, Ralph A.}, title = {Pre-therapy Somatostatin-Receptor-Based Heterogeneity Predicts Overall Survival in Pancreatic Neuroendocrine Tumor Patients Undergoing Peptide Receptor Radionuclide Therapy}, series = {Molecular Imaging and Biology}, journal = {Molecular Imaging and Biology}, issn = {1536-1632}, doi = {https://doi.org/10.1007/s11307-018-1252-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164624}, year = {2018}, abstract = {Purpose: Early identification of aggressive disease could improve decision-support in pancreatic neuroendocrine tumor (pNET) patients prior to peptide receptor radionuclide therapy (PRRT). The prognostic value of intratumoral textural features (TF) determined by baseline somatostatin receptor (SSTR)-PET before PRRT was analyzed. Procedures: 31 patients with G1/G2 pNET were enrolled (G2, n=23/31). Prior to PRRT with [\(^{177}\)Lu]DOTATATE (mean, 3.6 cycles), baseline SSTR-PET/CT was performed. By segmentation of 162 (median per patient, 5) metastases, intratumoral TF were computed. The impact of conventional PET parameters (SUV\(_{mean/max}\)), imaging-based TF as well as clinical parameters (Ki67, CgA) for prediction of both progression-free (PFS) and overall survival (OS) after PRRT was evaluated. Results: Within a median follow-up of 3.7y, tumor progression was detected in 21 patients (median, 1.5y) and 13/31 deceased (median, 1.9y). In ROC analysis, the TF Entropy, reflecting derangement on a voxel-by-voxel level, demonstrated predictive capability for OS (cutoff=6.7, AUC=0.71, p=0.02). Of note, increasing Entropy could predict a longer survival (>6.7, OS=2.5y, 17/31), whereas less voxel-based derangement portended inferior outcome (<6.7, OS=1.9y, 14/31). These findings were supported in a G2 subanalysis (>6.9, OS=2.8y, 9/23 vs. <6.9, OS=1.9y, 14/23). Kaplan-Meier analysis revealed a significant distinction between high- and low-risk groups using Entropy (n=31, p<0.05). For those patients below the ROC-derived threshold, the relative risk of death after PRRT was 2.73 (n=31, p=0.04). Ki67 was negatively associated with PFS (p=0.002); however, SUVmean/max failed in prognostication (n.s.). Conclusions: In contrast to conventional PET parameters, assessment of intratumoral heterogeneity demonstrated superior prognostic performance in pNET patients undergoing PRRT. This novel PET-based strategy of outcome prediction prior to PRRT might be useful for patient risk stratification.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @article{WernerIlhanLehneretal.2018, author = {Werner, Rudolf A. and Ilhan, Harun and Lehner, Sebastian and Papp, L{\´a}szl{\´o} and Zs{\´o}t{\´e}r, Norbert and Schatka, Imke and Muegge, Dirk O. and Javadi, Mehrbod S. and Higuchi, Takahiro and Buck, Andreas K. and Bartenstein, Peter and Bengel, Frank and Essler, Markus and Lapa, Constantin and Bundschuh, Ralph A.}, title = {Pre-therapy Somatostatin-Receptor-Based Heterogeneity Predicts Overall Survival in Pancreatic Neuroendocrine Tumor Patients Undergoing Peptide Receptor Radionuclide Therapy}, series = {Molecular Imaging and Biology}, journal = {Molecular Imaging and Biology}, issn = {1536-1632}, doi = {10.1007/s11307-018-1252-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167168}, year = {2018}, abstract = {Purpose: Early identification of aggressive disease could improve decision-support in pancreatic neuroendocrine tumor (pNET) patients prior to peptide receptor radionuclide therapy (PRRT). The prognostic value of intratumoral textural features (TF) determined by baseline somatostatin receptor (SSTR)-PET before PRRT was analyzed. Procedures: 31 patients with G1/G2 pNET were enrolled (G2, n=23/31). Prior to PRRT with [\(^{177}\)Lu]DOTATATE (mean, 3.6 cycles), baseline SSTR-PET/CT was performed. By segmentation of 162 (median per patient, 5) metastases, intratumoral TF were computed. The impact of conventional PET parameters (SUV\(_{mean/max}\)), imaging-based TF as well as clinical parameters (Ki67, CgA) for prediction of both progression-free (PFS) and overall survival (OS) after PRRT was evaluated. Results: Within a median follow-up of 3.7y, tumor progression was detected in 21 patients (median, 1.5y) and 13/31 deceased (median, 1.9y). In ROC analysis, the TF Entropy, reflecting derangement on a voxel-by-voxel level, demonstrated predictive capability for OS (cutoff=6.7, AUC=0.71, p=0.02). Of note, increasing Entropy could predict a longer survival (>6.7, OS=2.5y, 17/31), whereas less voxel-based derangement portended inferior outcome (<6.7, OS=1.9y, 14/31). These findings were supported in a G2 subanalysis (>6.9, OS=2.8y, 9/23 vs. <6.9, OS=1.9y, 14/23). Kaplan-Meier analysis revealed a significant distinction between high- and low-risk groups using Entropy (n=31, p<0.05). For those patients below the ROC-derived threshold, the relative risk of death after PRRT was 2.73 (n=31, p=0.04). Ki67 was negatively associated with PFS (p=0.002); however, SUVmean/max failed in prognostication (n.s.). Conclusions: In contrast to conventional PET parameters, assessment of intratumoral heterogeneity demonstrated superior prognostic performance in pNET patients undergoing PRRT. This novel PET-based strategy of outcome prediction prior to PRRT might be useful for patient risk stratification.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @article{WernerWeichKircheretal.2018, author = {Werner, Rudolf A. and Weich, Alexander and Kircher, Malte and Solnes, Lilja B. and Javadi, Mehrbod S. and Higuchi, Takahiro and Buck, Andreas K. and Pomper, Martin G. and Rowe, Steven and Lapa, Constantin}, title = {The theranostic promise for neuroendocrine tumors in the late 2010s - Where do we stand, where do we go?}, series = {Theranostics}, volume = {8}, journal = {Theranostics}, number = {22}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170264}, pages = {6088-6100}, year = {2018}, abstract = {More than 25 years after the first peptide receptor radionuclide therapy (PRRT), the concept of somatostatin receptor (SSTR)-directed imaging and therapy for neuroendocrine tumors (NET) is seeing rapidly increasing use. To maximize the full potential of its theranostic promise, efforts in recent years have expanded recommendations in current guidelines and included the evaluation of novel theranostic radiotracers for imaging and treatment of NET. Moreover, the introduction of standardized reporting framework systems may harmonize PET reading, address pitfalls in interpreting SSTR-PET/CT scans and guide the treating physician in selecting PRRT candidates. Notably, the concept of PRRT has also been applied beyond oncology, e.g. for treatment of inflammatory conditions like sarcoidosis. Future perspectives may include the efficacy evaluation of PRRT compared to other common treatment options for NET, novel strategies for closer monitoring of potential side effects, the introduction of novel radiotracers with beneficial pharmacodynamic and kinetic properties or the use of supervised machine learning approaches for outcome prediction. This article reviews how the SSTR-directed theranostic concept is currently applied and also reflects on recent developments that hold promise for the future of theranostics in this context.}, subject = {Positronen-Emissions-Tomografie}, language = {en} }