Primär lokalisiertes Prostatakarzinom: Vergleich der non-invasiven Diagnostik mittels präoperativer ¹¹C-Cholin-PET/CT-Untersuchung und postoperativen (histologisch gesicherten) Ergebnissen

Mit dieser Untersuchung wurde grundsätzlich der Fragestellungen nachgegangen, ob es mit Hilfe der präoperativen 11C-Cholin-PET/CT-Untersuchung möglich ist, ein primär lokalisiertes Prostatakarzinom nachzuweisen und ob die Ergebnisse bezüglich der Tumorlokalisation sowie der Lymphknotendetektion mit der postoperativen Histologie vergleichbar sind. In diese Studie wurden insgesamt 43 Patienten einbezogen. Davon stellte sich bei 41 Patienten ein histologisch gesichertes Adenokarzinom der Prostata heraus, ein Patient wurde aufgrund eines Rezidivs operiert und ein Patient bot das histologische Bild einer Prostatitis. Im Vergleich mit der Pathohistologie zeigte die visuelle 11C-Cholin-PET/CT bezüglich der Tumordetektion eine Sensitivität von 92,68% bei einer Treffergenauigkeit von 90,70%. Die semiquantitative Auswertung mittels SUVmax-Wert Bestimmung (>3,0) erreichte hier 85,37% Sensitivität bei einer Treffergenauigkeit von 83,72%. Im Hinblick auf die exakte Seitenlokalisation (Stadium T2a/b vs. T2c) zeigte sich eine Tendenz zum Overstaging bei einer Sensitivität von 58% (visuell und semiquantitativ). Unter Kenntnis des kleinen Patientenkollektivs zeigten sich für beide Methoden (visuell und semiquantitativ) geringe und zudem stark schwankende Sensitivitäten in der Vorhersage der Kapselinfiltration (T3a) und der Samenblaseninfiltration (0%-75%) bei hoher Spezifität (85%-98%). Im Lymphknotenstaging konnte bei ca. 500 postoperativ aufgearbeiteten Lymphknoten immerhin eine Treffergenauigkeit von 90%-95% (visuell vs. semiquantitativ) erreicht werden. Diese Studie lässt demnach folgende Schlussfolgerungen zu: Die Ergebnisse bzgl. der Tumordetektion sind vielversprechend, die exakte lokale Tumorausdehnung ist mit der 11C-Cholin-PET/CT jedoch schwer zu diagnostizieren. Möglicherweise kann die Methode einen Beitrag zum Lymphknotenstaging leisten. Die Ergebnisse müssen jedoch in Studien mit deutlich größerer Fallzahl und multizentrischem Studiendesign validiert werden

Combined [18F]-Fluoroethylcholine PET/CT and 99mTc-Macroaggregated Albumin SPECT/CT Predict Survival in Patients With Intermediate-Stage Hepatocellular Carcinoma

Aim The aim of this study was to retrospectively analyze the prognostic value of combined Tc-99m-macroaggregated albumin (MAA) SPECT/CT and [F-18]-fluoroethylcholine (FEC) PET/CT before radioembolization for survival of patients with intermediate-stage hepatocellular carcinoma. Methods Twenty-four patients with known hepatocellular carcinoma Barcelona Clinic Liver Cancer stage B were eligible for this analysis. All patients were scheduled for radioembolization and received a pretherapeutic [F-18]FEC PET/CT scan as well as Tc-99m-MAA SPECT/CT for hepatopulmonary shunting. Laboratory and semiquantitative PET parameters and morphologic and metabolic (intersection) volumes of MAA and FEC were evaluated. Spearman correlation with overall survival, receiver operating curve analyses, univariate and multivariate Cox regression, and Kaplan-Meier-analysis was applied. Results All patients (5 female/19 male) are deceased within the observational period. Median survival was 395 days (51 days;range, 23-1122 days). The percentage of hypervascularized metabolically active tumor volume (vascularized tumor ratio;defined as high MAA and FEC uptake) correlated significantly with survival. Vascularized tumor ratio was a significant predictor in univariate and multivariate analyses (P = 0.026;hazard ratio, 11.65;95% confidence interval, 1.62-83.73;P = 0.015). Statistical significance was not reached by all other variables in multivariate analysis. Receiver operating curve analysis for 1-year survival revealed an area under the curve of 0.77 (P = 0.024) for vascularized tumor ratio. At a cutoff value of 9%, sensitivity, specificity, and positive and negative prediction were 83%, 67%, and 71% and 80% (P = 0.036). Patients with a higher tumor vascularization had a median survival of 274 +/- 80 versus 585 +/- 284 days (P = 0.015). Conclusion: s Hepatocellular carcinoma with high vascularization in metabolic active areas as assessed by combined FEC PET/CT and Tc-MAA SPECT/CT represents an unfavorable subgroup with reduced overall survival after radioembolization

European Journal of Nuclear Medicine and Molecular Imaging / [18F]DOPA PET/ceCT in diagnosis and staging of primary medullary thyroid carcinoma prior to surgery

Purpose Medullary thyroid carcinoma (MTC) is characterized by a high rate of metastasis. In this study we evaluated the ability of [18F]DOPA PET/ceCT to stage MTC in patients with suspicious thyroid nodules and pathologically elevated serum calcitonin (Ctn) levels prior to total thyroidectomy and lymph node (LN) dissection. Methods A group of 32 patients with sonographically suspicious thyroid nodules and pathologically elevated basal Ctn (bCtn) and stimulated Ctn (sCtn) levels underwent DOPA PET/ceCT prior to surgery. Postoperative histology served as the standard of reference for ultrasonography and DOPA PET/ceCT region-based LN staging. Univariate and multivariate regression analyses as well as receiver operating characteristic analysis were used to evaluate the correlations between preoperative and histological parameters and postoperative tumour persistence or relapse. Results Primary MTC was histologically verified in all patients. Of the 32 patients, 28 showed increased DOPA decarboxylase activity in the primary tumour (sensitivity 88%, mean SUVmax 10.5). Undetected tumours were exclusively staged pT1a. The sensitivities of DOPA PET in the detection of central and lateral metastatic neck LN were 53% and 73%, in contrast to 20% and 39%, respectively, for neck ultrasonography. Preoperative bCtn and carcinoembryonic antigen levels as well as cN1b status and the number of involved neck regions on DOPA PET/ceCT were predictive of postoperative tumour persistence/relapse in the univariate regression analysis (P < 0.05). Only DOPA PET/ceCT cN1b status remained significant in the multivariate analysis (P = 0.016, relative risk 4.02). Conclusion This study revealed that DOPA PET/ceCT has high sensitivity in the detection of primary MTC and superior sensitivity in the detection of LN metastases compared to ultrasonography. DOPA PET/ceCT identification of N1b status predicts postoperative tumour persistence. Thus, implementation of a DOPA-guided LN dissection might improve surgical success.(VLID)360071

Dual-Tracer PET-MRI-Derived Imaging Biomarkers for Prediction of Clinically Significant Prostate Cancer

Purpose: To investigate if imaging biomarkers derived from 3-Tesla dual-tracer [(18)F]fluoromethylcholine (FMC) and [68Ga]Ga-PSMAHBED-CC conjugate 11 (PSMA)-positron emission tomography can adequately predict clinically significant prostate cancer (csPC). Methods: We assessed 77 biopsy-proven PC patients who underwent 3T dual-tracer PET/mpMRI followed by radical prostatectomy (RP) between 2014 and 2017. We performed a retrospective lesion-based analysis of all cancer foci and compared it to whole-mount histopathology of the RP specimen. The primary aim was to investigate the pretherapeutic role of the imaging biomarkers FMC- and PSMA-maximum standardized uptake values (SUVmax) for the prediction of csPC and to compare it to the mpMRI-methods and PI-RADS score. Results: Overall, we identified 104 cancer foci, 69 were clinically significant (66.3%) and 35 were clinically insignificant (33.7%). We found that the combined FMC+PSMA SUVmax were the only significant parameters (p p = 0.049) for the prediction of csPC. ROC analysis showed an AUC for the prediction of csPC of 0.695 for PI-RADS scoring (95% CI 0.591 to 0.786), 0.792 for FMC SUVmax (95% CI 0.696 to 0.869), 0.852 for FMC+PSMA SUVmax (95% CI 0.764 to 0.917), and 0.852 for the multivariable CHAID model (95% CI 0.763 to 0.916). Comparing the AUCs, we found that FMC+PSMA SUVmax and the multivariable model were significantly more accurate for the prediction of csPC compared to PI-RADS scoring (p = 0.0123, p = 0.0253, respectively). Conclusions: Combined FMC+PSMA SUVmax seems to be a reliable parameter for the prediction of csPC and might overcome the limitations of PI-RADS scoring. Further prospective studies are necessary to confirm these promising preliminary results

Renal and Salivary Gland Functions after Three Cycles of PSMA-617 Therapy Every Four Weeks in Patients with Metastatic Castration-Resistant Prostate Cancer

Background: [177Lu]Lu-PSMA-617 radioligand therapy (PSMA-RLT) could affect kidney and salivary gland functions in metastatic castration-resistant prostate cancer (mCRPC) patients. Methods: We retrospectively analyzed clinical, renal, and salivary scintigraphy data and salivary [68Ga]Ga-PSMA-11 ligand PET scan measures such as metabolic volume and SUVmax values of 27 mCRPC men (mean age 71 ± 7 years) before and 4 weeks after receiving three cycles of PSMA-RLT every 4 weeks. Twenty-two patients additionally obtained renal and salivary scintigraphy prior to each cycle. A one-way ANOVA, post-hoc Scheffé test and Cochran’s Q test were applied to assess organ toxicity. Results: In total, 54 PSMA PET scans, 98 kidney, and 98 salivary scintigraphy results were evaluated. There were no significant differences for the ejection fraction, peak time, and residual activity after 5 min for both parotid and submandibular glands prior to each cycle and 4 weeks after the last cycle. Similarly, no significant differences in serum creatinine and renal scintigraphy parameters were observed prior to each cycle and 4 weeks after the last treatment. Despite there being no changes in the metabolic volume of both submandibular glands, SUVmax values dropped significantly (p &lt; 0.05). Conclusion: Results evidenced no alterations in renal function and only minimal impairment of salivary function of mCRPC patients who acquired an intense PSMA-RLT regimen every 4 weeks

Onctotarget / Analysis of hematological parameters as prognostic markers for toxicity and survival of 223Radium treatment

Radium (Ra) has emerged as treatment prolonging survival in patients with metastatic castration-resistant prostate cancer (CRPC). As Ra can cause hematotoxicity (HT), pre-existing hematopoiesis might influence the efficacy of Ra and the rate of hematotoxicity, but as to our knowledge such data has not been published yet, we retrospectively conducted an analysis on patients receiving Ra. 54 patients treated with Ra had a median survival of 67 weeks, which was significantly reduced in patients with pre-existing Hb toxicity (Tox) grade 2 (48 weeks P = 0.008) as compared to grade 1 (67 weeks) and normal levels of Hb (not reached); survival in patients with Plt Tox grade 1 was significantly reduced (44 weeks) as compared to normal Plt counts (71 weeks, P = 0.033). Patients with impaired hematopoiesis regarding Hb and Plts developed significantly more grade 3 and 4 HT (Hb < 10 g/dl: 42.9% [3/7] vs 10.6% [5/47], P < 0.001; Plt < 150 G/L: 28.6% [2/7] vs 6.4% [3/47], P = 0.002) and received significantly fewer treatment cycles (Hb <10 g/dl: 5.1 vs 5.8, P = 0.04; Plt < 150 G/L: 3.4 vs 5.6, P < 0.001). These results imply that pre-existing impaired hematopoiesis, in particular thrombocytopenia and anemia, before 223Ra therapy, is an important risk factor for worse outcome of treatment with Ra.(VLID)470946

Relationship between PSA kinetics and [18F]fluorocholine PET/CT detection rates of recurrence in patients with prostate cancer after total prostatectomy

Purpose The aim of the present study was to identify prostate-specific antigen (PSA) threshold levels, as well as PSA velocity, progression rate and doubling time in relation to the detectability and localization of recurrent lesions with [18F]fluorocholine (FC) PET/CT in patients after radical prostatectomy. Methods The study group comprised 82 consecutive patients with biochemical relapse after radical prostatectomy. PSA levels measured at the time of imaging were correlated with the FC PET/CT detection rates in the entire group with PSA velocity (in 48 patients), with PSA doubling time (in 47 patients) and with PSA progression (in 29 patients). Results FC PET/CT detected recurrent lesions in 51 of the 82 patients (62%). The median PSA value was significantly higher in PET-positive than in PET-negative patients (4.3 ng/ml vs. 1.0 ng/ml; p Conclusion In a study cohort of patients with biochemical recurrence of prostate cancer after radical prostatectomy there emerged clear PSA thresholds for the presence of FC PET/CT-detectable lesions

Does Delayed-Time-Point Imaging Improve18F-FDG-PET in Patients with MALT Lymphoma?: Observations in a Series of 13 Patients

To determine whether in patients with extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue lymphoma (MALT), delayed–time-point 2-(18)F-fluoro-2-deoxy-d-glucose-positron emission tomography ((18)F-FDG-PET) performs better than standard–time-point (18)F-FDG-PET. MATERIALS AND METHODS: Patients with untreated histologically verified MALT lymphoma, who were undergoing pretherapeutic (18)F-FDG-PET/computed tomography (CT) and consecutive (18)F-FDG-PET/magnetic resonance imaging (MRI), using a single (18)F-FDG injection, in the course of a larger-scale prospective trial, were included. Region-based sensitivity and specificity, and patient-based sensitivity of the respective (18)F-FDG-PET scans at time points 1 (45–60 minutes after tracer injection, TP1) and 2 (100–150 minutes after tracer injection, TP2), relative to the reference standard, were calculated. Lesion-to-liver and lesion-to-blood SUV(max) (maximum standardized uptake values) ratios were also assessed. RESULTS: (18)F-FDG-PET at TP1 was true positive in 15 o f 23 involved regions, and (18)F-FDG-PET at TP2 was true-positive in 20 of 23 involved regions; no false-positive regions were noted. Accordingly, region-based sensitivities and specificities were 65.2% (confidence interval [CI], 45.73%–84.67%) and 100% (CI, 100%-100%) for (18)F-FDG-PET at TP1; and 87.0% (CI, 73.26%–100%) and 100% (CI, 100%-100%) for (18)F-FDG-PET at TP2, respectively. FDG-PET at TP1 detected lymphoma in at least one nodal or extranodal region in 7 of 13 patients, and (18)F-FDG-PET at TP2 in 10 of 13 patients; accordingly, patient-based sensitivity was 53.8% (CI, 26.7%–80.9%) for (18)F-FDG-PET at TP1, and 76.9% (CI, 54.0%–99.8%) for (18)F-FDG-PET at TP2. Lesion-to-liver and lesion-to-blood maximum standardized uptake value ratios were significantly lower at TP1 (ratios, 1.05 ± 0.40 and 1.52 ± 0.62) than at TP2 (ratios, 1.67 ± 0.74 and 2.56 ± 1.10; P = 0.003 and P = 0.001). CONCLUSIONS: Delayed–time-point imaging may improve (18)F-FDG-PET in MALT lymphoma

European Journal of Nuclear Medicine and Molecular Imaging / Quantitative assessment of atherosclerotic plaques on 18F-FDG PET/MRI : comparison with a PET/CT hybrid system

Purpose PET with 18F-FDG has the potential to assess vascular macrophage metabolism. 18F-FDG is most often used in combination with contrast-enhanced CT to localize increased metabolism to specific arterial lesions. Novel 18F-FDG PET/MRI hybrid imaging shows high potential for the combined evaluation of atherosclerotic plaques, due to the superior morphological conspicuity of plaque lesions. The purpose of this study was to evaluate the reliability and accuracy of 18F-FDG PET/MRI uptake quantification compared to PET/CT as a reference standard in patients with carotid atherosclerotic plaques. Methods The study group comprised 34 consecutive oncological patients with carotid plaques who underwent both PET/CT and PET/MRI with 18F-FDG on the same day. The presence of atherosclerotic plaques was confirmed by 3 T MRI scans. Maximum standardized uptake values (SUVmax) for carotid plaque lesions and the average SUV of the blood pool within the adjacent internal jugular vein were determined and target-to-blood ratios (TBRs, plaque to blood pool) were calculated. Results Atherosclerotic lesions with maximum colocalized focal FDG uptake were assessed in each patient. SUVmax values of carotid plaque lesions were significantly lower on PET/MRI than on PET/CT (2.3 0.6 vs. 3.1 0.6; P < 0.01), but were significantly correlated between PET/CT and PET/MRI (Spearmans r = 0.67, P < 0.01). In contrast, TBRmax values of plaque lesions were similar on PET/MRI and on PET/CT (2.2 0.3 vs. 2.2 0.3; P = 0.4), and again were significantly correlated between PET/MRI and PET/CT (Spearmans r = 0.73, P < 0.01). Considering the increasing trend in SUVmax and TBRmax values from early to delayed imaging time-points on PET/CT and PET/MRI, respectively, with continuous clearance of radioactivity from the blood, a slight underestimation of TBRmax values may also be expected with PET/MRI compared with PET/CT. Conclusion SUVmax and TBRmax values are widely accepted reference parameters for estimation of the radioactivity of atherosclerotic plaques on PET/CT. However, due to a systematic underestimation of SUVmax and TBRmax with PET/MRI, the optimal cut-off values indicating the presence of inflamed plaque tissue need to be newly defined for PET/MRI.KLI 382(VLID)346802