[en] A continuous-flow left ventricular assist device (LVAD) is a new and highly promising therapy in supporting end-stage heart failure patients, either bridging them to heart transplantation or as a destination therapy. Infection is one of the major complications associated with LVAD implants. "1"8F-FDG PET/CT has already been shown to be useful in the detection of LVAD infection. The goal of this study was to compare the diagnostic accuracy of different PET analysis techniques (visual grading versus SUVmax and metabolic volume). We retrospectively analyzed 48 patients with implanted LVAD who underwent an "1"8F-FDG PET/CT that were either suspected to have a driveline or device infection or inflammation of unknown origin. PET/CT was analyzed qualitatively (visual grading) and quantitatively (SUVmax and metabolic volume) and matched to the final clinical diagnosis concerning driveline infection. The final diagnosis (standard of reference) was made at the end of clinically recorded follow-up or transplantation and included microbiological cultures of the driveline exit site and/or surgical samples, and clinical signs of infection despite negative cultures as well as recurrence of symptoms. Sensitivity, specificity, positive and negative predictive value were 87.5%, 79%, 81% and 86% for visual score, 87.5%, 87.5%, 87.5% and 87.5% for SUVmax and 96%, 87.5%, 88.5%, 95.5% for metabolic volume, respectively. ROC analysis revealed an AUC of.929 for SUVmax and.969 for metabolic volume. Both SUVmax and metabolic volume had a high detection rate of patients with driveline infection (21/24 = 91.5% true positive vs. 23/26 = 88.5% true positive, respectively). However, metabolic volume detected more patients without any infection correctly (1/22 = 4.5% false negative vs. 3/24 = 12.5% false negative). "1"8F-FDG PET/CT is a valuable tool for the diagnosis of LVAD driveline infection with high diagnostic accuracy. Particularly the use of the metabolic volume yields very high accuracy and performs slightly better than SUVmax. (orig.)

[en] Coronary artery calcium scoring can complement myocardial perfusion imaging (MPI). The purpose of this study was to evaluate the feasibility and accuracy of using the CalciumScore-CT derived from a combined SPECT/CT device also for SPECT attenuation correction (AC). The study group comprised 99 patients who underwent both post-stress and rest MPI using a two-slice SPECT/CT system. For AC, one of the two scans was accompanied by a CalciumScore-CT scan (CalciumScore-CTAC) and the other by a conventional spiral CT (AttenCorr-CT) scan (AttenCorr-CTAC). In 48 patients the CalciumScore-CT scan was acquired with the post-stress scan and the AttenCorr-CT scan with the rest scan, and in 51 patients the order was reversed. The accuracy of the images based on AC was determined qualitatively by consensus reading with respect to the clinical diagnoses as well as quantitatively by comparing the perfusion summed stress scores (SSS) and the summed rest scores (SRS) between attenuation-corrected and uncorrected images. In comparison to the uncorrected images CalciumScore-CTAC led to regional inaccuracies in 14 of 51 of studies (27.5 %) versus 12 of 48 studies (25 %) with AttenCorr-CTAC for the stress studies and in 5 of 48 (10 %) versus 1 of 51 (2 %) for the rest studies, respectively. This led to intermediate and definite changes in the final diagnosis (ischaemia and/or scarring) in 12 % of the studies (12 of 99) and in 7 % of the studies (7 of 99) with CalciumScore-CTAC and in 9 % of the studies (9 of 99) and 4 % of the studies (4 of 99) with AttenCorr-CTAC. Differences in SSS and SRS with respect to the uncorrected images were greater for the CalciumScore-CTAC images than for the AttenCorr-CTAC images (ΔSSS 4.5 ± 5.6 and 2.1 ± 4.4, p = 0.023; ΔSRS 4.2 ± 4.9 and 1.6 ± 3.2, p = 0.004, respectively). Using the same CT scan for calcium scoring and SPECT AC is feasible. Image interpretation must, however, include uncorrected images since CT-based AC relatively often introduces artefacts into the myocardial perfusion images. This effect is somewhat more pronounced with CalciumScore-CTAC than with AttenCorr-CTAC. (orig.)

[en] Based on a single older study it is established dogma that TSH levels should be ≥30 mU/l at the time of postoperative "1"3"1I ablation in differentiated thyroid cancer (DTC) patients. We sought to determine whether endogenous TSH levels, i.e. after levothyroxine withdrawal, at the time of ablation influence ablation success rates, recurrence-free survival and DTC-related mortality. A total of 1,873 patients without distant metastases referred for postoperative adjuvant "1"3"1I therapy were retrospectively included from 1991 onwards. Successful ablation was defined as stimulated Tg <1 μg/l. Age, gender and the presence of lymph node metastases were independent determinants of TSH levels at the time of ablation. TSH levels were not significantly related to ablation success rates (p = 0.34), recurrence-free survival (p = 0.29) or DTC -elated mortality (p = 0.82), but established risk factors such as T-stage, lymph node metastases and age were. Ablation was successful in 230 of 275 patients (83.6 %) with TSH <30 mU/l and in 1,359 of 1,598 patients (85.0 %) with TSH ≥30 mU/l. The difference was not significant (p = 0.55). Of the whole group of 1,873 patients, 21 had recurrent disease. There were no significant differences in recurrence rates between patients with TSH <30 mU/l and TSH ≥30 mU/l (p = 0.16). Ten of the 1,873 patients died of DTC. There were no significant differences in DTC-specific survival between patients with TSH <30 mU/l and TSH ≥30 mU/l (p = 0.53). The precise endogenous TSH levels at the time of "1"3"1I ablation are not related to the ablation success rates, recurrence free survival and DTC related mortality. The established dogma that TSH levels need to be ≥30 mU/l at the time of "1"3"1I ablation can be discarded. (orig.)

[en] To evaluate the diagnostic potential of PET/MRI with ["1"8F]FDG in comparison to PET/CT in patients with differentiated thyroid cancer suspected or known to have dedifferentiated. The study included 31 thyroidectomized and remnant-ablated patients who underwent a scheduled ["1"8F]FDG PET/CT scan and were then enrolled for a PET/MRI scan of the neck and thorax. The datasets (PET/CT, PET/MRI) were rated regarding lesion count, conspicuity, diameter and characterization. Standardized uptake values were determined for all ["1"8F]FDG-positive lesions. Histology, cytology, and examinations before and after treatment served as the standards of reference. Of 26 patients with a dedifferentiated tumour burden, 25 were correctly identified by both ["1"8F]FDG PET/CT and PET/MRI. Detection rates by PET/CT and PET/MRI were 97 % (113 of 116 lesions) and 85 % (99 of 113 lesions) for malignant lesions, and 100 % (48 of 48 lesions) and 77 % (37 of 48 lesions) for benign lesions, respectively. Lesion conspicuity was higher on PET/CT for both malignant and benign pulmonary lesions and in the overall rating for malignant lesions (p < 0.001). There was a difference between PET/CT and PET/MRI in overall evaluation of malignant lesions (p < 0.01) and detection of pulmonary metastases (p < 0.001). Surgical evaluation revealed three malignant lesions missed by both modalities. PET/MRI additionally failed to detect 14 pulmonary metastases and 11 benign lesions. In patients with thyroid cancer and suspected or known dedifferentiation, ["1"8F]FDG PET/MRI was inferior to low-dose ["1"8F]FDG PET/CT for the assessment of pulmonary status. However, for the assessment of cervical status, ["1"8F]FDG PET/MRI was equal to contrast-enhanced neck ["1"8F]FDG PET/CT. Therefore, ["1"8F]FDG PET/MRI combined with a low-dose CT scan of the thorax may provide an imaging solution when high-quality imaging is needed and high-energy CT is undesirable or the use of a contrast agent is contraindicated. (orig.)

[en] To study the clinical yield of diagnostic whole body "1"3"1I scintigraphy (DxWBS) in the follow-up of differentiated thyroid carcinoma (DTC) patients in relation to stimulated thyroglobulin (sTg) in the initial post-ablation setting, as well as in the setting of repeated monitoring in course of further DTC follow-up. Data of 1420 thyroidectomized and radioiodine remnant-ablated DTC patients following a well-defined therapy and standardized follow-up protocol were evaluated. DxWBS and sTg were evaluated separately and in combination for various follow-up time points. The factual administration of the recorded indication for further oncologic therapy (excluding radioiodine therapies given for minimal normal remnants) within the following 4 months after follow-up served as the standard of reference. Furthermore, DxWBS was compared to post therapy WBS and SPECT(/CT) if available. Subgroup analysis was carried out for DTC patients < 45 years old at diagnosis without distant metastasis. The diagnostic impact of cervical ultrasound was not assessed. sTg can identify the patients at risk better than DxWBS. Furthermore, the most sensitive time point to assess response appears to be a time point beyond 3 months after RRA. When information received from both imaging and laboratory measurements are concordant, i.e. both construe absence of remaining disease, only a small fraction of patients (<2%) required treatment in the future. The strongest effect was observed 12 months after RRA. Only 0.9% of the negative DxWBS patients with concordant sTg below the functional sensitivity at this time point required treatment thereafter. A complete omission of DxWBS in the post-RRA surveillance of DTC is justified once DxWBS is negative and sTg is below the functional sensitivity (with no evidence of thyroglobulin antibodies), as patients showing this combination of test results (especially 12 months after RRA) show an at worst marginal risk of recurrence. In all other cases DxWBS may still be justified. (orig.)

[en] New molecular imaging approaches featuring the assessment of inflammatory processes in the vascular wall on top of existing anatomic and functional vessel imaging procedures could emerge as decisive tools for the understanding and prevention of cardiovascular events. In this respect imaging approaches addressing specific molecular and cellular targets in atherosclerosis are of high interest. This review summarizes the rationale and current status of nuclear imaging probes which possess high translational potential.

[en] The purpose of this study was to determine whether ["6"8Ga]DOTATATE PET/MRI with diffusion-weighted imaging (DWI) can replace or complement ["1"8F]FDG PET/CT in patients with radioactive-iodine (RAI)-refractory differentiated thyroid cancer (DTC). The study population comprised 12 patients with elevated thyroglobulin and a negative RAI scan after thyroidectomy and RAI remnant ablation who underwent both ["1"8F]FDG PET/CT and ["6"8Ga]DOTATATE PET/MRI within 8 weeks of each other. The presence of recurrent cancer was evaluated on a per-patient, per-organ and per-lesion basis. Histology, and prior and follow-up examinations served as the standard of reference. Recurrent or metastatic tumour was confirmed in 11 of the 12 patients. ["6"8Ga]DOTATATE PET(/MRI) correctly identified the tumour burden in all 11 patients, whereas in one patient local relapse was missed by ["1"8F]FDG PET/CT. In the lesion-based analysis, overall lesion detection rates were 79/85 (93 %), 69/85 (81 %) and 27/82 (33 %) for ["1"8F]FDG PET/CT, ["6"8Ga]DOTATATE PET/MRI and DWI, respectively. ["1"8F]FDG PET(/CT) was superior to ["6"8Ga]DOTATATE PET(/MRI) in the overall evaluation and in the detection of pulmonary metastases. In the detection of extrapulmonary metastases, ["6"8Ga]DOTATATE PET(/MRI) showed a higher sensitivity than ["1"8F]FDG PET(/CT), at the cost of lower specificity. DWI achieved only poor sensitivity and was significantly inferior to ["1"8F]FDG PET in the lesion-based evaluation in the detection of both extrapulmonary and pulmonary metastases. ["1"8F]FDG PET/CT was more sensitive than ["6"8Ga]DOTATATE PET/MRI in the evaluation of RAI-refractory DTC, mostly because of its excellent ability to detect lung metastases. In the evaluation of extrapulmonary lesions, ["6"8Ga]DOTATATE PET(/MRI) was more sensitive and ["1"8F]FDG PET(/CT) more specific. Furthermore, DWI did not provide additional information and cannot replace ["1"8F]FDG PET for postoperative monitoring of patients with suspected RAI-refractory DTC. (orig.)

[en] An accurate postoperative assessment is pivotal to inform postoperative ${}^{131}$I treatment in patients with differentiated thyroid cancer (DTC). We developed a predictive model for post-treatment whole-body scintigraphy (PT-WBS) results (as a proxy for persistent disease) by adopting a decision tree model. Age, sex, histology, T stage, N stage, risk classes, remnant estimation, TSH, and Tg were identified as potential predictors and were put into regression algorithm (conditional inference tree, ctree) to develop a risk stratification model for predicting the presence of metastases in PT-WBS. The lymph node (N) stage identified a partition of the population into two subgroups (N-positive vs N-negative). Among N-positive patients, a Tg value > 23.3 ng/mL conferred a 83% probability to have metastatic disease compared to those with lower Tg values. Additionally, N-negative patients were further substratified in three subgroups with different risk rates according to their Tg values. The model remained stable and reproducible in the iterative process of cross validation. We developed a simple and robust decision tree model able to provide reliable informations on the probability of persistent/metastatic DTC after surgery. These information may guide post-surgery ${}^{131}$I administration and select patients requiring curative rather than adjuvant ${}^{131}$I therapy schedules.

[en] This narrative review aims to summarize the relationship between hyperthyroidism, upper reference range thyroid hormone (TH) levels, and cancer, and to address the clinical management of hyperthyroidism in cancer patients. A comprehensive search was performed by an independent reviewer through Google Scholar and PubMed Electronic databases. All searches were restricted to English language manuscripts published between 2000 and 2020. Numerous in vitro, in vivo, and population-based studies suggest cancer-stimulating effect of triiodothyronine and thyroxin. THs are presented as mediators for tumor growth, proliferation, and progression. Many population and case-control studies suggest an increased risk of several solid but also hematologic malignancies in relation to hyperthyroidism and upper normal range TH levels. However, results are not unambiguous. In this review, we will summarize population and case–control studies that investigated the relationship between hyperthyroidism, upper reference range TH levels, lower thyrotropin (TSH) levels, lower reference range TSH levels with cancer risk, cancer prognosis, and cancer outcome. The vast majority of evidence suggests an association between clinical and subclinical hyperthyroidism with the risk of developing several types of cancer. Furthermore, hyperthyroidism is also linked with a poorer cancer prognosis. In this review, we will also discuss the diagnosis of hyperthyroidism in patients with pre-existing cancer and cover the management of hyperthyroidism in cancer patients, with special attention on the role of nuclear medicine. It is crucial to emphasize the importance of the rapid establishment of euthyroidism, and consequently, the importance of radioiodine therapy, as the therapy of choice in most cancer patients. We want to show that in this day and age there still is a high relevance for I-131 to achieve a permanent solution and thus likely reduce the risk of adverse influence of hyperthyroidism on the occurrence of new and course of existing cancer cases.

[en] The purpose of this retrospective, multicenter study was to assess efficacy of PSMA-PET/CT-guided salvage radiotherapy (sRT) in patients with recurrent or persistent PSA after primary surgery and PSA levels < 0.2 ng/ml. The study included patients from a pooled cohort (n = 1223) of 11 centers from 6 countries. Patients with PSA levels > 0.2 ng/ml prior to sRT or without sRT to the prostatic fossa were excluded. The primary study endpoint was biochemical recurrence-free survival (BRFS) and BR was defined as PSA nadir after sRT + 0.2 ng/ml. Cox regression analysis was performed to assess the impact of clinical parameters on BRFS. Recurrence patterns after sRT were analyzed. The final cohort consisted of 273 patients; 78/273 (28.6%) and 48/273 (17.6%) patients had local or nodal recurrence on PET/CT. The most frequently applied sRT dose to the prostatic fossa was 66-70 Gy (n = 143/273, 52.4%). SRT to pelvic lymphatics was delivered in 87/273 (31.9%) patients and androgen deprivation therapy was given to 36/273 (13.2%) patients. After a median follow-up time of 31.1 months (IQR: 20-44), 60/273 (22%) patients had biochemical recurrence. The 2- and 3-year BRFS was 90.1% and 79.2%, respectively. The presence of seminal vesicle invasion in surgery (p = 0.019) and local recurrences in PET/CT (p = 0.039) had a significant impact on BR in multivariate analysis. In 16 patients, information on recurrence patterns on PSMA-PET/CT after sRT was available and one had recurrent disease inside the RT field. This multicenter analysis suggests that implementation of PSMA-PET/CT imaging for sRT guidance might be of benefit for patients with very low PSA levels after surgery due to promising BRFS rates and a low number of relapses within the sRT field.