Refine
Has Fulltext
- yes (72)
Is part of the Bibliography
- yes (72)
Year of publication
Document Type
- Journal article (59)
- Conference Proceeding (7)
- Preprint (6)
Language
- English (72) (remove)
Keywords
- PET (21)
- Positronen-Emissions-Tomografie (20)
- positron emission tomography (15)
- theranostics (9)
- neuroendocrine tumor (8)
- prostate cancer (7)
- SPECT (6)
- 18F-FDG (5)
- PET/CT (5)
- PRRT (5)
- PSMA (5)
- RADS (5)
- SSTR (5)
- CXCR4 (4)
- inflammation (4)
- molecular imaging (4)
- norepinephrine transporter (4)
- prostate-specific membrane antigen (4)
- radioligand therapy (4)
- sympathetic nervous system (4)
- 18F-DCFPyL (3)
- 18F-LMI1195 (3)
- DaTscan (3)
- Prostate Cancer (3)
- ageing (3)
- peptide receptor radionuclide therapy (3)
- somatostatin receptor (3)
- vandetanib (3)
- 11C-HED (2)
- 18F-FDS (2)
- Ioflupane (2)
- MIBG (2)
- MRI (2)
- Myokarditis (2)
- PSMA-PET (2)
- PSMA-RADS (2)
- Parkinson (2)
- Parkinson Disease (2)
- Parkinson-Krankheit (2)
- Positron Emission Tomography (2)
- SSTR-RADS (2)
- Stammzelle (2)
- TKI (2)
- Virchow Node (2)
- [177Lu]-DOTATATE/-DOTATOC (2)
- [68Ga] (2)
- antidepressant (2)
- cardiomyocytes (2)
- chemokine receptor (2)
- diabetes (2)
- fatty acid (2)
- heart (2)
- heart failure (2)
- hiPSC-CM (2)
- induced pluripotent stem cells (2)
- kidney (2)
- machine learning (2)
- medullary thyroid carcinoma (2)
- molecular medicine (2)
- myocardial sympathetic innervation imaging (2)
- myocarditis (2)
- personalized medicine (2)
- personalized treatment (2)
- precision medicine (2)
- prostate-specific membrane antigen (PSMA) (2)
- reporting and data system (2)
- somatostatin receptor (SSTR) (2)
- stem cell therapy (2)
- tracer (2)
- tumor heterogeneity (2)
- tyrosine kinase inhibitor (2)
- 11C-Hydroxyephedrine (1)
- 11C-hydroxyephedrine (1)
- 123I-Ioflupane (1)
- 123I-mIBG (1)
- 123I-metaiodobenzylguanidine (1)
- 177Lu (1)
- 18F-DCFPL (1)
- 18F-flurpiridaz (1)
- 18FFBnTP (1)
- 2- deoxy-2-(18F)fluoro-D-glucose (1)
- 2-deoxy-2-(18F)fluoro-D-glucose (1)
- 2-deoxy-2-18F-fluoro-D-sorbitol (1)
- 5IA-SPECT (1)
- 68Ga-DOTANOC (1)
- 68Ga-DOTATATE (1)
- 68Ga-DOTATATE/-TOC (1)
- 68Ga-DOTATOC (1)
- 99mTc-DTPA (1)
- <sup>18</sup>F-FDG (1)
- <sup>68</sup>Ga-Pentixafor (1)
- AI (1)
- Alzheimer’s disease (1)
- Antidepressants (1)
- C-X-C motif chemokine receptor 4 (1)
- COVID-19 (1)
- CTCAE (1)
- CXCR4-targeting (1)
- Cardiovascular diseases (1)
- DCGAN (1)
- DOTATOC (1)
- DYT1 (1)
- Dystonia (1)
- ECG (1)
- FV45 (1)
- GAN (1)
- GCA (1)
- GI (1)
- Ganglia (1)
- Gastrointestinal (1)
- Glomerular filtration (1)
- HFmrEF (1)
- HMDP hydroxymethylene diphosphonate (1)
- Heart failure (1)
- Herz (1)
- Imaging pitfalls (1)
- Journal of Nuclear Cardiology (1)
- MAG3 (1)
- MDD (1)
- MI-RADS (1)
- MPI (1)
- Magnetresonanztomografie (1)
- Medullärer Schilddrüsenkrebs (1)
- Metaiodobenzylguanidine (1)
- Myocardial-perfusion SPECT (1)
- NEC (1)
- NET (1)
- Neuroendocrine (1)
- Neuroendocrine Tumor (1)
- Nierenfunktionsstörung (1)
- OXPHOS (1)
- Oncology (1)
- P-glycoprotein expression (1)
- PMR (1)
- PROMISE (1)
- PSMA I&T (1)
- PSMA-617 (1)
- PSMA-RADS-3A (1)
- PSMA-RADS-3B (1)
- PSMA-targeted PET (1)
- Pancreas (1)
- Parkinson disease (1)
- Parkinsonism (1)
- Parkinson’s disease (1)
- Pitfall (1)
- Positron-Emission Tomography (1)
- Positronenemissionstomografie (1)
- Prostata (1)
- RLT (1)
- ROS (1)
- Radiofluorine (1)
- Radionuclide Therapy (1)
- Radiotracer (1)
- SARS-CoV-2 (1)
- SPECT Scanner (1)
- SPECT/CT (1)
- SSTR-PET (1)
- SUV (1)
- Simvastatin (1)
- Single-Photon-Emissions-Computertomographie (1)
- Sodium-Glucose Cotransporters (SGLTs) (1)
- Standardisierung (1)
- T-shaped π-π stacking (1)
- T-shaped π–π stacking (1)
- Technetium Tc 99m Sestamibi Rats (1)
- Tracer (1)
- ZDF rats (1)
- [177Lu]/[90Y]PentixaTher (1)
- [18F]FDG PET/CT (1)
- [68Ga]DOTATOC (1)
- [68Ga]PentixaFor (1)
- [68Ga]Pentixafor (1)
- [\(^{68}\)Ga]Ga-FAPI (1)
- [\(^{68}\)Ga]Pentixafor (1)
- \(^{177}\)Lu (1)
- \(^{18}\)F (1)
- \(^{18}\)F-FDG (1)
- \(^{18}\)F-fluorodeoxyglucose (1)
- \(^{68}\)Ga (1)
- amyloid-β (Aβ) (1)
- angiotensin II type 1 receptor (1)
- antidepressants (1)
- artificial intelligence (1)
- autonomic nervous system (1)
- benzylguanidine (1)
- biomarkers (1)
- blood flow (1)
- butyrylcholinesterase (1)
- carbamate (1)
- cardiac (1)
- cardiac innervation imaging (1)
- cardiac nerve (1)
- cardiac neurohormonal system (1)
- cardiac sympathetic nerve system (1)
- cardiac sympathetic nervous system (1)
- cardioprotective potential (1)
- cell biology (1)
- cognitive decline (1)
- combination (1)
- computational biology and bioinformatics (1)
- contractility (1)
- coronary artery disease (1)
- depression (1)
- diabetic cardiomyopathy (1)
- dilated cardiomyopathy with ataxia (1)
- dopamine (1)
- dopamine acetylcholine (1)
- editorial (1)
- ejection fraction (1)
- endocrinology (1)
- endoradiotherapy (1)
- enzyme kinetics (1)
- fibroblast activation protein (1)
- fluorine-18 (1)
- genetics (1)
- giant cell arteritis (1)
- glomerular filtration rate (1)
- heart failure with mid-range ejection fraction (1)
- hematotoxicity (1)
- hydroxyephedrine (1)
- interobserver (1)
- interreader (1)
- left-ventricular function (1)
- mIBG (1)
- magnetic resonance imaging (1)
- major depressive disorder (1)
- matched pair (1)
- mechanisms retention (1)
- medium-sized animals (1)
- meningioma (1)
- metabolism (1)
- mitochondria (1)
- molecular biology (1)
- mouse (1)
- moycardial sympathetic innervation (1)
- myocardial perfusion imaging (1)
- nephrology (1)
- nephrotoxicity (1)
- neuroblastoma (1)
- neuroendocrine neoplasia (1)
- neuroendocrine neoplasms (NEN) (1)
- neuroendocrine tumors (NET) (1)
- neurology (1)
- nicotinic receptors (1)
- nonhuman primates (1)
- nuclear cardiology (1)
- ollimator (1)
- organic cation transporter (1)
- pancreas (1)
- papillary thyroid carcinoma (PTC) (1)
- performance (1)
- peripheral injury (1)
- phaeochromocytoma (1)
- phenethylguanidine (1)
- polymyalgia rheumatica (1)
- post-reconstruction filtering (1)
- quality (1)
- quantification (1)
- radioiodine (1)
- radiotracer (1)
- radiotracer kinetics (1)
- radiotracers (1)
- rats (1)
- renal (1)
- renal failure (1)
- renal function (1)
- renal imaging (1)
- renal scintigraphy (1)
- renin-angiotensin system (1)
- reporting and data systems (1)
- scanner (1)
- second hit (1)
- selpercatinib (1)
- sepsis (1)
- sigma-1 receptor-directed molecular imaging (1)
- single photon emission computed tomography: sympathetic nerve (1)
- skeletal (1)
- small animal SPECT (1)
- small-animal imaging (1)
- solid tumors (1)
- split renal function (1)
- standardization (1)
- standardized reporting (1)
- statin (1)
- stem cells (1)
- stem-cell research (1)
- storage vesicle turnover (1)
- stroke (1)
- structure–activity relationships (1)
- sympathetic nerve (1)
- thyroid carcinoma (TC) (1)
- unilateral ureteral obstruction (1)
- urology (1)
- valsartan (1)
- vasculature (1)
- vasculitis (1)
Institute
- Klinik und Poliklinik für Nuklearmedizin (72) (remove)
Sonstige beteiligte Institutionen
- Johns Hopkins School of Medicine (17)
- Johns Hopkins University School of Medicine (5)
- Johns Hopkins School of Medicine, Baltimore, MD, U.S. (3)
- Department of Biomedical Imaging, National Cerebral and Cardiovascular Research Center, Suita, Japan (2)
- Division of Medical Technology and Science, Department of Medical Physics and Engineering, Course of Health Science, Osaka University Graduate School of Medicine, Suita Japan (2)
- Institut for Molecular Biology and CMBI, Department of Genomics, Stem Cell Biology and Regenerative Medicine, Leopold-Franzens-University Innsbruck, Innsbruck, Austria (2)
- Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Science, Baltimore, MD, USA (2)
- Department of Nuclear Medicine, Kanazawa University (1)
- Hospital Augsburg, Augsburg, Germany (1)
- Johns Hopkins School of Medicine, Baltimore, MD, USA (1)
We investigated in vivo brain nicotinic acetylcholine receptor (nAChR) distribution in cognitively intact subjects with Parkinson's disease (PD) at an early stage of the disease. Fourteen patients and 13 healthy subjects were imaged with single photon emission computed tomography and the radiotracer 5-[(123)I]iodo-3-[2(S)-2-azetidinylmethoxy]pyridine ([(123)I]5IA). Patients were selected according to several criteria, including short duration of motor signs (<7 years) and normal scores at an extensive neuropsychological evaluation. In PD patients, nAChR density was significantly higher in the putamen, the insular cortex and the supplementary motor area and lower in the caudate nucleus, the orbitofrontal cortex, and the middle temporal gyrus. Disease duration positively correlated with nAChR density in the putamen ipsilateral (ρ = 0.56, p < 0.05) but not contralateral (ρ = 0.49, p = 0.07) to the clinically most affected hemibody. We observed, for the first time in vivo, higher nAChR density in brain regions of the motor and limbic basal ganglia circuits of subjects with PD. Our findings support the notion of an up-regulated cholinergic activity at the striatal and possibly cortical level in cognitively intact PD patients at an early stage of disease.
Heart failure is one of the growing causes of death especially in developed countries due to longer life expectancy. Although many pharmacological and instrumental therapeutic approaches have been introduced for prevention and treatment of heart failure, there are still limitations and challenges. Nuclear cardiology has experienced rapid growth in the last few decades, in particular the application of single photon emission computed tomography (SPECT) and positron emission tomography (PET), which allow non-invasive functional assessment of cardiac condition including neurohormonal systems involved in heart failure; its application has dramatically improved the capacity for fundamental research and clinical diagnosis. In this article, we review the current status of applying radionuclide technology in non-invasive imaging of neurohormonal system in the heart, especially focusing on the tracers that are currently available. A short discussion about disadvantages and perspectives is also included.
PURPOSE:
To evaluate the heart and the Tc-99m-sestamibi biodistribution after statin pretreatment in a rat model of abdominal sepsis.
METHODS:
Twenty-four Wistar rats were randomly distributed into four groups (n=6 per group): 1) sepsis with simvastatin treatment, 2) sepsis with vehicle, 3) sham control with simvastatin and 4) sham control with vehicle. 24 hours after cecal ligation and puncture rats received 1.0MBq of Tc-99m-sestamibi i.v. 30min after, animals were euthanized for ex-vivo tissue counting and myocardium histological analysis.
RESULTS:
Myocardial histologic alterations were not detected 24 hours post-sepsis. There was significantly increased cardiac Tc-99m-sestamibi activity in the sepsis group with simvastatin treatment (1.9\(\pm\)0.3%ID/g, p<0.001) in comparison to the sepsis group+vehicle (1.0\(\pm\)0.2% ID/g), control sham group+ simvastatin (1.2\(\pm\)0.3% ID/g) and control sham group (1.3\(\pm\)0.2% ID/g). Significant Tc-99m-sestamibi activity in liver, kidney and lungs was also detected in the sepsis group treated with simvastatinin comparison to the other groups.
CONCLUSIONS:
Statin treatment altered the biodistribution of Tc-99m-sestamibi with increased cardiac and solid organ activity in rats with abdominal sepsis, while no impact on controls. Increased myocardial tracer activity may be a result of a possible protection effect due to increased tissue perfusion mediated by statins.
Isolated generalized dystonia is a central motor network disorder characterized by twisted movements or postures. The most frequent genetic cause is a GAG deletion in the Tor1a (DYT1) gene encoding torsinA with a reduced penetrance of 30-40 % suggesting additional genetic or environmental modifiers. Development of dystonia-like movements after a standardized peripheral nerve crush lesion in wild type (wt) and Tor1a+/- mice, that express 50 % torsinA only, was assessed by scoring of hindlimb movements during tail suspension, by rotarod testing and by computer-assisted gait analysis. Western blot analysis was performed for dopamine transporter (DAT), D1 and D2 receptors from striatal and quantitative RT-PCR analysis for DAT from midbrain dissections. Autoradiography was used to assess the functional DAT binding in striatum. Striatal dopamine and its metabolites were analyzed by high performance liquid chromatography. After nerve crush injury, we found abnormal posturing in the lesioned hindlimb of both mutant and wt mice indicating the profound influence of the nerve lesion (15x vs. 12x relative to control) resembling human peripheral pseudodystonia. In mutant mice the phenotypic abnormalities were increased by about 40 % (p < 0.05). This was accompanied by complex alterations of striatal dopamine homeostasis. Pharmacological blockade of dopamine synthesis reduced severity of dystonia-like movements, whereas treatment with L-Dopa aggravated these but only in mutant mice suggesting a DYT1 related central component relevant to the development of abnormal involuntary movements. Our findings suggest that upon peripheral nerve injury reduced torsinA concentration and environmental stressors may act in concert in causing the central motor network dysfunction of DYT1 dystonia.
Peptide Receptor Radionuclide Therapy (PRRT) for the treatment of neuroendocrine tumors may lead to kidney deterioration. This study aimed to evaluate the suitability of \(^{99m}\)Tc-mercaptoacetyltriglycine (\(^{99m}\)Tc-MAG3) clearance for the early detection of PRRT-induced changes on tubular extraction (TE). TE rate (TER) was measured prior to 128 PRRT cycles (7.6±0.4 GBq \(^{177}\)Lu-octreotate/octreotide each) in 32 patients. TER reduction during PRRT was corrected for age-related decrease and analyzed for the potential to predict loss of glomerular filtration (GF). The GF rate (GFR) as measure for renal function was derived from serum creatinine. The mean TER was 234 ± 53 ml/min/1.73 m² before PRRT (baseline) and 221 ± 45 ml/min/1.73 m² after a median follow-up of 370 days. The age-corrected decrease (mean: -3%, range: -27% to +19%) did not reach significance (p=0.09) but significantly correlated with the baseline TER (Spearman p=-0.62, p<0.001). Patients with low baseline TER showed an improved TER after PRRT, high decreases were only observed in individuals with high baseline TER. Pre-therapeutic TER data were inferior to plasma creatinine-derived GFR estimates in predicting late nephropathy. TER assessed by \(^{99m}\)Tc-MAG3clearance prior to and during PRRT is not suitable as early predictor of renal injury and an increased risk for late nephropathy.
Brown adipose tissue (BAT) is an attractive therapeutic target to combat diabetes and obesity due to its ability to increase glucose expenditure. In a genetic rat model (ZDF fa/fa) of type-2 diabetes and obesity, we aimed to investigate glucose utilization of BAT by \(^{18}\)F-FDG PET imaging. Male Zucker diabetic fatty (ZDF) and Male Zucker lean (ZL) control rats were studied at 13 weeks. Three weeks prior to imaging, ZDF rats were randomized into a no-restriction (ZDF-ND) and a mild calorie restriction (ZDF-CR) group. Dynamic \(^{18}\)F-FDG PET using a dedicated small animal PET system was performed under hyperinsulinemic-euglycemic clamp. \(^{18}\)F-FDG PET identified intense inter-scapular BAT glucose uptake in all ZL control rats, while no focally increased \(^{18}\)F-FDG uptake was detected in all ZDF-ND rats. Mild but significant improved BAT tracer uptake was identified after calorie restriction in diabetic rats (ZDF-CR). The weight of BAT tissue and fat deposits were significantly increased in ZDF-CR and ZDF-ND rats as compared to ZL controls, while UCP-1 and mitochondrial concentrations were significantly decreased. Whitening and severely impaired insulin-stimulated glucose uptake in BAT was confirmed in a rat model of type-2 diabetes. Additionally, calorie restriction partially restored the impaired BAT glucose uptake.
Introduction: The prognosis of medullary thyroid carcinoma (MTC) is poor using common chemotherapeutic approaches. However, during the last years encouraging results of recently introduced tyrosine kinase inhibitors (TKI) such as vandetanib have been published. In this study we aimed to correlate the results of \(^{18}\)F-fluorodeoxyglucose ([\(^{18}\)F]FDG) positron emission tomography (PET) imaging with treatment outcome.
Methods: Eighteen patients after thyroidectomy with recurrent/advanced MTC lesions receiving vandetanib (300 mg orally/day) could be analysed. A baseline \(^{18}\)F-FDG PET prior to and a follow-up \(^{18}\)F-FDG PET 3 months after TKI initiation were performed. During follow-up, tumor progression was assessed every 3 months including computed tomography according to RECIST. Progression-free survival (PFS) was correlated with the maximum standardized uptake value of \(^{18}\)F-FDG in lymph nodes (SUV(LN)max) or visceral metastases (SUV(MTS)max) as well as with clinical parameters using ROC analysis.
Results: Within median 3.6 years of follow-up, 9 patients showed disease progression at median 8.5 months after TKI initiation. An elevated glucose consumption assessed by baseline \(^{18}\)F-FDG PET (SUV(LN)max > 7.25) could predict a shorter PFS (2 y) with an accuracy of 76.5% (SUV(LN)max <7.25, 4.3 y; p=0.03). Accordingly, preserved tumor metabolism in the follow-up PET (SUV(MTS)max >2.7) also demonstrated an unfavorable prognosis (accuracy, 85.7%). On the other hand, none of the clinical parameters reached significance in response prediction.
Conclusions: In patients with advanced and progressive MTC, tumors with higher metabolic activity at baseline are more aggressive and more prone to progression as reflected by a shorter PFS; they should be monitored more closely. Preserved glucose consumption 3 months after treatment initiation was also related to poorer prognosis.
C-X-C motif chemokine receptor 4 (CXCR4) and somatostatin receptors (SSTR) are overexpressed in gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). In this study, we aimed to elucidate the feasibility of non-invasive CXCR4 positron emission tomography/computed tomography (PET/CT) imaging in GEP-NET patients using [\(^{68}\)Ga]Pentixafor in comparison to \(^{68}\)Ga-DOTA-D-Phe-Tyr3-octreotide ([\(^{68}\)Ga]DOTATOC) and \(^{18}\)F-fluorodeoxyglucose ([\(^{18}\)F]FDG). Twelve patients with histologically proven GEP-NET (3xG1, 4xG2, 5xG3) underwent [\(^{68}\)Ga]DOTATOC, [\(^{18}\)F]FDG, and [\(^{68}\)Ga]Pentixafor PET/CT for staging and planning of the therapeutic management. Scans were analyzed on a patient as well as on a lesion basis and compared to immunohistochemical staining patterns of CXCR4 and somatostatin receptors SSTR2a and SSTR5. [\(^{68}\)Ga]Pentixafor visualized tumor lesions in 6/12 subjects, whereas [\(^{18}\)F]FDG revealed sites of disease in 10/12 and [\(^{68}\)Ga]DOTATOC in 11/12 patients, respectively. Regarding sensitivity, SSTR-directed PET was the superior imaging modality in all G1 and G2 NET. CXCR4-directed PET was negative in all G1 NET. In contrast, 50% of G2 and 80% of G3 patients exhibited [\(^{68}\)Ga]Pentixafor-positive tumor lesions. Whereas CXCR4 seems to play only a limited role in detecting well-differentiated NET, increasing receptor expression could be non-invasively observed with increasing tumor grade. Thus, [\(^{68}\)Ga]Pentixafor PET/CT might serve as non-invasive read-out for evaluating the possibility of CXCR4-directed endoradiotherapy in advanced dedifferentiated SSTR-negative tumors.
Objective: Radiotracers targeting prostate-specific membrane antigen (PSMA) have increasingly been recognized as showing uptake in a number of normal structures, anatomic variants, and non-prostate-cancer pathologies. We aimed to explore the frequency and degree of uptake in peripheral ganglia in patients undergoing PET with the PSMA-targeted agent \(^{18}\)F-DCFPyL.
Methods: A total of 98 patients who underwent \(^{18}\)F-DCFPyL PET/CT imaging were retrospectively analyzed. This included 76 men with prostate cancer (PCa) and 22 patients with renal cell carcinoma (RCC; 13 men, 9 women). Scans were evaluated for uptake in the cervical, stellate, celiac, lumbar and sacral ganglia. Maximum standardized uptake value corrected to body weight (SUV\(_{max}\)), and maximum standardized uptake value corrected to lean body mass (SUL\(_{max}\)) were recorded for all ganglia with visible uptake above background. Ganglia-to-background ratios were calculated by dividing the SUV\(_{max}\) and SUL\(_{max}\) values by the mean uptake in the ascending aorta (Aortamean) and the right gluteus muscle (Gluteusmean).
Results: Overall, 95 of 98 (96.9%) patients demonstrated uptake in at least one of the evaluated peripheral ganglia. With regard to the PCa cohort, the most frequent sites of radiotracer accumulation were lumbar ganglia (55/76, 72.4%), followed by the cervical ganglia (51/76, 67.1%). Bilateral uptake was found in the majority of cases [lumbar 44/55 (80%) and cervical 30/51 (58.8%)]. Additionally, discernible radiotracer uptake was recorded in 50/76 (65.8%) of the analyzed stellate ganglia and in 45/76 (59.2%) of the celiac ganglia, whereas only 5/76 (6.6%) of the sacral ganglia demonstrated \(^{18}\)F-DCFPyL accumulation. Similar findings were observed for patients with RCC, with the most frequent locations of radiotracer uptake in both the lumbar (20/22, 90.9%) and cervical ganglia (19/ 22, 86.4%). No laterality preference was found in mean PSMA-ligand uptake for either the PCa or RCC cohorts.
Conclusion: As PSMA-targeted agents become more widely disseminated, the patterns of uptake in structures that are not directly relevant to patients’ cancers must be understood. This is the first systematic evaluation of the uptake of \(^{18}\)F-DCFPyL in ganglia demonstrating a general trend with a descending frequency of radiotracer accumulation in lumbar, cervical, stellate, celiac, and sacral ganglia. The underlying biology that leads to variability of PSMA-targeted radiotracers in peripheral ganglia is not currently understood, but may provide opportunities for future research.
Introduction: Therapeutic options in advanced medullary thyroid carcinoma (MTC) have markedly improved since the introduction of tyrosine kinase inhibitors (TKI). We
aimed to assess the role of metabolic imaging using 2-deoxy-2-(\(^{18}\)F)fluoro-D-glucose (\(^{18}\)F-FDG) positron emission tomography/computed tomography (PET/CT) shortly before and 3 months after initiation of TKI treatment.
Methods: Eighteen patients with advanced and progressive MTC scheduled for vandetanib treatment underwent baseline \(^{18}\)F-FDG PET/CT prior to and 3 months after TKI treatment initiation. During follow-up, CT scans were performed every 3 months and analyzed according to Response Evaluation Criteria In Solid Tumors (RECIST). The predictive value for estimating progression-free (PFS) and overall survival (OS) was examined by investigating \(^{18}\)F-FDG mean/maximum standardized uptake values (SUVmean/max) of the metabolically most active lesion as well as by analyzing clinical parameters (tumor marker doubling times {calcitonin, carcinoembryonic antigen (CEA)}, prior therapies, RET (rearranged during transfection) mutational status, and disease type).
Results: Within a median follow-up of 5.2 years, 9 patients experienced disease progression after a median time interval of 2.1y whereas the remainder had ongoing disease control (n=5 partial response and n=4 stable disease). Eight of the 9 patients with progressive disease died from MTC after a median of 3.5y after TKI initiation.
Pre-therapeutic SUVmean >4.0 predicted a significantly shorter PFS (PFS: 1.9y vs. 5.2y; p=0.04). Furthermore, sustained high 18F-FDG uptake at 3 months with a SUVmean>2.8 tended to portend an unfavorable prognosis with a PFS of 1.9y (vs. 3.5y; p=0.3). Prolonged CEA doubling times were significantly correlated with longer PFS (r=0.7) and OS (r=0.76, p<0.01, respectively). None of the other clinical parameters had prognostic significance.
Conclusions: Pre-therapeutic \(^{18}\)F-FDG PET/CT holds prognostic information in patients with advanced MTC scheduled for treatment with the TKI vandetanib. Low tumor metabolism of SUVmean < 4.0 prior to treatment predicts longer progression-free survival.
Background: Precise regional quantitative assessment of renal function is limited with conventional \(^{99m}\)Tc-labeled renal radiotracers. A recent study reported that the positron emission tomography (PET) radiotracer 2-deoxy-2-(\(^{18}\)F-fluorosorbitol (\(^{18}\)F-FDS) has ideal pharmacokinetics for functional renal imaging. Furthermore, (\(^{18}\)F-FDS is available via simple reduction from routinely used 2-deoxy-2-(\(^{18}\)F-fluoro-D-glucose ((\(^{18}\)F-FDG). We aimed to further investigate the potential of (\(^{18}\)F-FDS PET as a functional renal imaging agent using rat models of kidney diseases.
Methods: Two different rat models of renal impairment were investigated: Glycerol induced acute renal failure (ARF) by intramuscular administration of glycerol in hind legs and unilateral ureteral obstruction (UUO) by ligation of the left ureter. 24h after these treatments, dynamic 30 min 18F-FDS PET data were acquired using a dedicated small animal PET system. Urine 18F-FDS radioactivity 30 min after radiotracer injection was measured together with co-injected \(^{99m}\)Tc-diethylenetriaminepentaacetic acid (\(^{99m}\)Tc-DTPA) urine activity. Results: Dynamic PET imaging demonstrated rapid (\(^{18}\)F-FDS accumulation in the renal cortex and rapid radiotracer excretion via kidneys in control healthy rats. On the other hand, significantly delayed renal radiotracer uptake (continuous slow uptake) was observed in ARF rats and UUO-treated kidneys. Measured urine radiotracer concentrations of (\(^{18}\)F-FDS and \(^{99m}\)Tc-DTPA were well correlated (R=0.84, P<0.05).
Conclusions: (\(^{18}\)F-FDS PET demonstrated favorable kinetics for functional renal imaging in rat models of kidney diseases. Advantages of high spatiotemporal resolution of PET imaging and simple tracer production could potentially complement or replace conventional renal scintigraphy in select cases and significantly improve the diagnostic performance of renal functional imaging.
Background: \(^{123}\)I-metaiodobenzylguanidine (mIBG) provides independent prognostic value for risk stratification among heart failure patients, but the use of concomitant medication should not impact its quantitative information. We aimed to evaluate the four most-prescribed antidepressants currently used as a first‑line treatment for patients with major depressive disorder (MDD) and their potential on altering mIBG imaging results.
Methods: The inhibition effect of four different types of antidepressants (desipramine, escitalopram, venlafaxine and bupropion) for MDD treatment on \(^{131}\)I-mIBG uptake was assessed by in-vitro cell uptake assays using human neuroblastoma SK-N-SH cells. The half maximal inhibitory concentration (IC50) of tracer uptake was determined from dose-response curves. To evaluate the effects of IV pretreatment with desipramine (1.5 mg/kg) and escitalopram (2.5, 15 mg/kg) on mIBG cardiac uptake, in-vivo planar 123I-mIBG scans in healthy New Zealand White Rabbits were conducted. Results: The IC50 values of desipramine, escitalopram, venlafaxine and bupropion on \(^{131}\)I-mIBG cellular uptake were 11.9 nM, 7.5 μM, 4.92 μM, and 12.9 μM, respectively. At the maximum serum concentration (Cmax, as derived by previous clinical trials), the inhibition rates of 131I-mIBG uptake were 90.6 % for desipramine, 25.5 % for venlafaxine, 11.7 % for bupropion and 0.72 % for escitalopram. A low inhibition rate for escitalopram in the cell uptake study triggered investigation of an in-vivo rabbit model: with dosage considerably higher than clinical practice, the non-inhibitory effect of escitalopram was confirmed. Furthermore, pretreatment with desipramine led to a marked reduction of cardiac 123I-mIBG uptake.
Conclusions: In the present in-vitro binding assay and in-vivo rabbit study, the selective-serotonin reuptake inhibitor escitalopram had no major impact on neuronal cardiac mIBG uptake within therapeutic dose ranges, while other types of first-line antidepressants for MDD treatment led to a significant decrease. These preliminary results warrant further confirmatory clinical trials regarding the reliability of cardiac mIBG imaging, in particular, if the patient’s neuropsychiatric status would not tolerate withdrawal of a potentially norepinephrine interfering antidepressant.
Reliable standards and criteria for somatostatin receptor (SSTR) positron emission tomography (PET) are still lacking. We herein propose a structured reporting system on a 5-point scale for SSTR-PET imaging, titled SSTR-RADS version 1.0, which might serve as a standardized assessment for both diagnosis and treatment planning in neuroendocrine tumors (NET). SSTR-RADS could guide the imaging specialist in interpreting SSTR-PET scans, facilitate communication with the referring clinician so that appropriate work-up for equivocal findings is pursued, and serve as a reliable tool for patient selection for planned Peptide Receptor Radionuclide Therapy.
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.