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In DLBCL, the Deauville scoring system (DS) is the standard for PET/CT response assessment. An alternative system, based on the semi-quantitative change in standardized uptake values, namely ΔSUVmax, has been reported to be more objective than the DS. We aimed to compare ΔSUVmax and DS for risk stratification of DLBCL patients on end-of-treatment (EoT) PET. 108 consecutive patients were included. 2-year EFS Kaplan-Meier survival analyses and Cox regression models were performed. 2-year EFS was significantly different between favorable ΔSUVmax (favΔ < -86.5%) and unfavorable ΔSUVmax (unfavΔ ≥ -86.5%) patients: 100.0% ± 0.0 versus 58.3% ± 14.2 ( p  = 0.001). On Cox multivariable regression, ΔSUVmax status was the only independent predictor of 2-year EFS, outperforming DS. Therefore, ΔSUVmax should be computed for non-responder patients, especially DS4, as the 2-year EFS is not different between responders and non-responders in the case of favΔ. Further studies are needed in order to confirm this hypothesis.

Background: We compared quantification of MBF and myocardial flow reserve (MFR) with a 99mTc-sestamibi CZT-SPECT to 15 O-water PET., Methods: SPECT MBF for thirty patients in the WATERDAY study was re-analyzed by QPET software with motion correction and optimal placement of the arterial input function. 15 O-water PET MBF was re-quantified using dedicated software. Inter-operator variability was assessed using repeatability coefficients (RPC)., Results: Significant correlations were observed between global (r = 0.91, P < 0.001) and regional MBF (r = 0.86, P < 0.001) with SPECT compared to PET. Global MBF (rest 0.95 vs 1.05 ml/min/g, P = 0.07; stress 2.62 vs 2.68 mL/min/g, P = 0.17) and MFR (2.65 vs 2.75, P = 0.86) were similar between SPECT and PET. Rest (0.81 vs 0.98 mL/min/g, P = 0.03) and stress MBF (1.98 vs 2.61 mL/min/g, P = 0.01) in right coronary artery (RCA) were lower with SPECT compared to PET. However, MFR in the RCA territory was similar (2.54 vs 2.77, P = 0.21). The SPECT-PET RPC for global MBFs and MFR were 0.95 mL/min/g and 0.94, with inter-observer RPC of 0.59 mL/min/g and 0.74, respectively., Conclusions: MBF and MFR derived from CZT-SPECT with motion correction and optimal placement of the arterial input function showed good agreement with 15 O-water PET, as well as low inter-operator variability., (© 2019. American Society of Nuclear Cardiology.)

Aim: To perform a comprehensive analysis of discordances between contrast-enhanced CT (ceCT) and 18 F-FDG PET/CT in the evaluation of the extra-cerebral treatment monitoring in patients with stage IV melanoma., Materials and Methods: We conducted a retrospective monocentric observational study over a 3-year period in patients referred for 18 F-FDG PET/CT and ceCT in the framework of therapy monitoring of immune checkpoint (ICIs) as of January 2017. Imaging reports were analyzed by two physicians in consensus. The anatomical site responsible for discordances, as well as induced changes in treatment were noted., Results: Eighty patients were included and 195 pairs of scans analyzed. Overall, discordances occurred in 65 cases (33%). Eighty percent of the discordances (52/65) were due to 18 F-FDG PET/CT scans upstaging the patient. Amongst these discordances, 17/52 (33%) led to change in patient's management, the most frequent being radiotherapy of a progressing site. ceCT represented 13/65 (20%) of discordances and induced changes in patients' management in 2/13 cases (15%). The most frequent anatomical site involved was subcutaneous for 18 F-FDG PET/CT findings and lung or liver for ceCT., Conclusions: Treatment monitoring with 18 F-FDG PET/CT is more efficient than ceCT and has a greater impact in patient's management.

Purpose: To seek for the minimal duration per bed position with a digital PET system without compromising image quality and lesion detection in patients requiring fast 18 F-FDG PET imaging., Materials and Methods: 19 cancer patients experiencing pain or dyspnea and 9 pediatric patients were scanned on a Vereos system. List mode data were reconstructed with decreasing time frame down to 10 s per bed position. Noise was evaluated in the liver, blood pool and muscle, and using target-to-background ratios. Five PET readers recorded image quality, number of clinically relevant foci and of involved anatomical sites in reconstructions ranging from 60 to 10 s per bed position, compared to the standard 90 s reconstruction., Results: The following reconstructions, which harboured a noise not significantly higher than that of the standard reconstruction, were selected for clinical evaluation: 1iterations/10 subsets/20 sec (1i10 s20 sec ), 1i10 s30 sec , and 2i10 sPSF60 sec. Only the 60 s per bed acquisition displayed similar target-to-background ratios compared to the standard reconstruction, but mean ratios were still higher than 2.0 for the 30 s reconstruction. Inter-rater agreement for the number of involved anatomical sites and detected lesion was good or almost perfect (Kappa: 0.64-0.91) for all acquisitions. In particular, kappa for the 30 s per bed acquisition was 0.78 and 0.91 for lesion and anatomical sites number, respectively. Intra-rater agreement was also excellent for the 30 s reconstruction (kappa = 0.72). Median estimated total PET acquisition time for the 1i10 s30 sec , and the standard reconstruction were 4 and 12 min, respectively., Conclusions: Fast imaging is feasible with state-of-the-art PET systems. Acquisitions of 30 s per bed position are feasible with the Vereos system, requiring optimization of reconstruction parameters., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Objectives: To explore the prognostic value of positron emission tomography (PET) radiomic features in the field of diffuse large B cell lymphoma (DLBCL) treated with a first-line immunochemotherapy., Methods: One-hundred thirty-two patients newly diagnosed with DLBCL were retrospectively included. PET studies were reconstructed using an ordered subset expectation maximisation algorithm with point spread function modelling. The total metabolic tumour volume (MTV) was recorded for each patient, and the volume of interest structure of the largest target lesion was used to compute 18 F-FDG textural parameters. Data was randomly split into training and validation datasets. Optimal cutoff values were determined by means of 2-year event-free survival (EFS) ROC analyses. Two-year EFS analyses were performed using Kaplan-Meier survival analyses and univariable and multivariable Cox regression models., Results: The median follow-up was 27 months, and the 2-year event-free survival (2y-EFS) was 77.3% in the entire population. ROC analyses for the 2y-EFS reached statistical significance for total MTV as well as four second-order metrics (homogeneity, contrast, correlation, dissimilarity) and five third-order metrics (LZE (Long-Zone Emphasis), LZLGE (Long-Zone Low-Grey Level Emphasis), LZHGE (Long-Zone High-Grey Level Emphasis), GLNU (Grey-Level Non-Uniformity) and ZP (Zone Percentage)). LZHGE displayed the highest ROC analysis accuracy (acc. = 0.76) and the best discriminant value on univariable Kaplan-Meier analysis (p < 0.0001, HR = 4.54). On multivariable analysis, including IPIaa, total MTV and LZHGE, LZHGE was the only independent predictor of 2y-EFS. These results were confirmed on the validation dataset., Conclusions: Baseline 18 F-FDG PET heterogeneity of the largest lymphoma lesion is a promising predictor of 2y-EFS in newly diagnosed DLBCL treated with immunochemotherapy., Key Points: • 18 F-FDG metabolic heterogeneity emerges as a new tool for survival prognostication of patients and has been explored in many solid tumours with promising results. • Baseline 18 F-FDG PET heterogeneity of the largest lymphoma lesion is an independent predictor of 2y-EFS in newly diagnosed DLBCL treated with immunochemotherapy. • DLBCL patients presenting with a heterogeneous tumour displayed a worse prognosis.

Background: Anal cancer is a relatively rare tumor of which incidence increases in developed countries. 18 F-FDG PET has been increasingly used for its post radio-chemotherapy evaluation. However, several authors have reported the risk of local false-positive findings leading to low specificity and positive predictive values. These false-positive results could be due to post-radiotherapy inflammation or infection but certainly also to physiological anal canal uptake that is observed on a regular basis in clinical practice. The purpose of this prospective study (NCT03506529; HYPHYCA) was therefore to seek predictive factors of physiological anal canal hypermetabolism., Materials and Methods: Over a 2-month period, patients aged 18 years old and more, referred for 18 F-FDG PET-CT at two EARL-accredited PET centers were included, after obtaining their informed and written consent. They were asked to fill in a questionnaire including seven closed questions about usual intestinal transit, ongoing medications relative to intestinal transit, history of digestive, and anal and/or pelvic diseases. Age, gender, and body mass index (BMI) were recorded. A single nuclear medicine physician visually and quantitatively analyzed anal canal uptake (SUV max&#95;EARL ) and assessed visual rectal content (air, feces, or both) and the largest rectal diameter (mm)., Results: Six hundred and thirteen patients were included (sex ratio F/M = 0.99) and 545 (89%) questionnaires were entirely completed. Significantly more males presented anal canal hypermetabolism (sex ratio (M/F) = 1.18 versus 0.85, p = 0.048). Moreover, patients with anal canal hypermetabolism had higher BMI (27.6 (5.7) kg/m 2 versus 23.9 (4.5) kg/m 2 , p < 0.0001), higher rate of hemorrhoid history (43% versus 27%, p = 0.016), and higher rate of rectum filled with only feces (21% versus 12%, p = 0.019) as compared to patients with no anal canal uptake. On logistic regression, all these variables were found to be independent predictors of the occurrence of an anal canal hypermetabolism. Odds ratio were 1.16 (1.12-1.20) per unit of BMI (kg/m 2 ) (p < 0.0001), 1.48 (1.04-2.11) for males (p = 0.030), 1.64 (1.10-2.45) for hemorrhoids history (p = 0.016), and 1.94 (1.147-3.22) for the rectum filled with only feces (p = 0.010)., Conclusion: According to our study, the predictive factors of physiological anal canal hypermetabolism are high BMI, male gender, hemorrhoid history, and rectum filled with only feces. This may pave the way to a more specific interpretation of post radio-chemotherapy PET evaluations of anal canal cancer, provided that other studies are conducted in this specific population., Trial Registration: This prospective study was registered at Clinicaltrial.gov: NCT03506529; HYPHYCA on April 24, 2018.

Background: Evaluate the physical performance of the VERITON CzT camera (Spectrum Dynamics, Caesarea, Israel) that benefits from new detection architecture enabling whole-body imaging compared to that of a conventional dual-head Anger camera., Methods: Different line sources and phantom measurements were performed on each system to evaluate spatial resolution, sensitivity, energy resolution and image quality with acquisition and reconstruction parameters similar to those used in clinical routine. Extrinsic resolution was assessed using 99m Tc capillary sources placed successively in air, in a head and in a body phantom filled with background activity. Spectral acquisitions for various radioelements used in nuclear medicine ( 99m Tc, 123 I, 201 Tl, 111 In) were performed to evaluate energy resolution by computing the FWHM of the measured photoelectric peak. Tomographic sensitivity was calculated by recording the total number of counts detected during tomographic acquisition for a set of source geometries representative of different clinical situations. Sensitivity was also evaluated in focus mode for the CzT camera, which consisted of forcing detectors to collect data in a reduced field-of-view. Image quality was assessed with a Jaszczak phantom filled with 350 MBq of 99m Tc and scanned on each system with 30-,20-,10- and 5-min acquisition times., Results: Extrinsic and tomographic resolution in the brain and body phantoms at the centre of the FOV was estimated at 3.55, 7.72 and 6.66 mm for the CzT system and 2.47, 7.75 and 7.72 mm for the conventional system, respectively. The energy resolution measured at 140 keV was 5.46% versus 9.21% for the Anger camera and was higher in a same manner for all energy peaks tested. Tomographic sensitivity for a point source in air was estimated at 236 counts·s -1 ·MBq -1 and increased to 1159 counts·s -1 ·MBq -1 using focus mode, which was 1.6 times and 8 times greater than the sensitivity measured on the scintillation camera (144 counts·s -1 ·MBq -1 ). Head and body measurements also showed higher sensitivity for the CzT camera in particular with focus mode. The Jaszczak phantom showed high image contrast uniformity and a high signal-to-noise ratio on the CzT system, even when decreasing acquisition time by 6-fold. Representative clinical cases are shown to illustrate these results., Conclusion: The CzT camera has a superior sensitivity, higher energy resolution and better image contrast than the conventional SPECT camera, whereas spatial resolution remains similar. Introduction of this new technology may change current practices in nuclear medicine such as decreasing acquisition time and activity injected to patient.

Aims: (1) To perform a comprehensive analysis of the time elapsed between the last G-CSF injection and the PET/CT examination on the biodistribution of 18 F-FDG, with emphasis on liver, spleen, and bone marrow uptake, and (2) to investigate whether an inversion of the liver to spleen ratio affects the Deauville scoring., Materials and Methods: Retrospectively included were 74 consecutive diffuse large B cell lymphoma (DLBCL) patients referred for baseline and interim examinations and receiving immunochemotherapy with various G-CSF regimens. A comprehensive evaluation considering baseline metabolic active tumour volume (MATV), factors affecting liver uptake, the type of G-CSF, and the time elapsed between chemotherapy/G-CSF and interim PET/CTs was performed., Results: Mean (± SD) percentage variations between baseline and interim PET/CTs (i-PET/CT) for bone marrow (%Variation&#95; BONE ), liver (%Variation&#95; LIVER ) and spleen (%Variation&#95; SPLEEN ) were equal to 32.0 ± 46.9%, 16.1 ± 42.8%, and 10.6 ± 51.1 %, respectively. %Variation&#95; LIVER and %Variation&#95; SPLEEN were higher in patients using lenograstim, but this was linked to lower uptakes at baseline and was therefore likely not due to G-CSF itself. The mean delay between G-CSF injection and i-PET/CT acquisition was not an independent explanatory variable for %Variation&#95; BONE , %Variation&#95; LIVER , and %Variation&#95; SPLEEN . On the contrary, %Variation&#95; BONE and %Variation&#95; SPLEEN were negatively correlated to the time-lapse between the end of chemotherapy and i-PET/CT: ρ = - 0.342 (p = 0.010) and ρ = - 0.529 (p < 0.0001), respectively. Patients with a time-lapse since the last injection of chemotherapy < 17 days displayed higher bone and spleen SUVmax EARL . %Variation&#95; LIVER was positively correlated to baseline MATV: ρ = 0.243 (p = 0.039). Patients displaying a high baseline MATV ≥ 177 cc had significantly lower liver SUVmax EARL at baseline. This difference was no longer observed at i-PET/CT, after tumours had shrunk., Conclusions: Neither the type of G-CSF used nor the time elapsed between its last injection and i-PET/CT examination independently influences bone, hepatic, or splenic uptakes at i-PET/CT. The major determinant for the occurrence of a bone or spleen hypermetabolism on i-PET/CT is the time elapsed between the chemotherapy and the examination, which should be maintained above 15 days. Inversion of the liver to spleen ratio appeared to be due to increased spleen hypermetabolism on i-PET/CT, making unlikely an impact on the Deauville scoring.

Objective: We evaluated the relative performances of dipyridamole (Dip) and regadenoson (Reg) in a cohort of patients referred for coronary artery disease diagnosis or follow-up using myocardial perfusion imaging., Materials and Methods: We retrospectively included 515 consecutive patients referred for 99m Tc-sestamibi myocardial perfusion single-photon emission computerized tomography (SPECT) on a cadmium-zinc-telluride (CZT) camera after pharmacologic stress. About three quarters ( n = 391, 76%) received Dip. Reg was administrated to patients with chronical respiratory disease or with body mass index (BMI) over 38 kg/m 2 ( n = 124, 24%). Patients with an abnormal stress scan (92%) underwent a rest imaging on the same day. Qualitative interpretation of perfusion images was achieved using QPS software, and the ischemic area was assessed using the 17-segment model. In patients undergoing a stress-rest protocol, perfusion polar plots were postprocessed using automated in-house software to quantify the extension, intensity, and location of the reversible perfusion defect. Statistical comparison between groups was performed using univariate and multivariate analysis., Results: Qualitative analysis concluded to myocardial ischemia in 70% of the patients (69% in the Dip group, 76% in the Reg group, P = ns). In those patients, the number of involved segments (Dip 2.5 ± 1.6, Reg 2.7 ± 1.6, P = ns) and the proportion of patients with an ischemic area larger than two segments (Dip 30%, Reg 37%, P = ns) were comparable. Automated quantification of the reversible perfusion defect demonstrated similar defect extension, intensity, and severity in the two groups. Defect location was identical at the myocardial segment and vascular territory scales., Conclusions: Reg and Dip showed equal performances for ischemic burden characterization using myocardial CZT SPECT., Competing Interests: There are no conflicts of interest.

When evaluating 18 F-FDG PET images with the Deauville score (DS), the quantification of tumor and reference organs limits the problem of optical misinterpretation. Compared with conventional reconstruction algorithms, point-spread function (PSF) modeling increases SUVs significantly in tumors but only moderately in the liver, which could affect the DS. We investigated whether the choice of the reconstruction algorithm affects the DS and whether discordance affects the capability of 18 F-FDG PET to stratify lymphoma patients. Methods: Overall, 126 patients with diffuse large B-cell lymphoma were included (56 female and 70 male; median age, 65 y; range, 20-88 y). PET data were reconstructed with the unfiltered PSF method. Additionally, a 6-mm filter was applied to PSF images to meet the requirements of the EANM Research Ltd. (EARL) harmonization program from the European Association of Nuclear Medicine (EANM) (PSF EARL ). One hundred interim PET (i-PET) and 95 end-of-treatment PET (EoT-PET) studies were analyzed. SUV max in the liver and aorta was determined using automatic volumes of interest and compared with SUV max in the residual mass with the highest 18 F-FDG uptake. Results: For i-PET, using PSF and PSF EARL , we classified patients as responders and nonresponders in 60 and 40 cases versus 63 and 37 cases, respectively. Five cases of major discordance (5.0%) occurred (i.e., changes from responder to nonresponder). For Eot-PET, patients were classified using PSF and PSF EARL as responders and nonresponders in 69 and 26 cases versus 72 and 23 cases, respectively. Three cases of major discordance (3.2%) occurred. Concordance (Cohen unweighted κ) between the PSF and the PSF EARL DS was 0.82 (95% confidence interval, 0.73-0.91) for i-PET and 0.89 (95% confidence interval, 0.81-0.96) for EoT-PET. The median follow-up periods were 28.4 and 27.4 mo for i-PET and EoT-PET, respectively. Kaplan-Meier analysis showed statistically significant differences in progression-free survival and overall survival among responders and nonresponders no matter which reconstruction was used for i-PET and EoT-PET. Conclusion: Neither DS nor risk stratification of diffuse large B-cell lymphoma patients is affected by the choice of PET reconstruction. Specifically, the use of PSF is not an issue in routine clinical processes or in multicenter trials. These findings have to be confirmed in escalation and deescalation procedures based on early i-PET., (© 2018 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: We assessed the feasibility of myocardial blood flow (MBF) and flow reserve (MFR) estimation using dynamic SPECT with a novel CZT camera in patients with stable CAD, in comparison with 15 O-water PET and fractional flow reserve (FFR)., Methods: Thirty patients were prospectively included and underwent FFR measurements in the main coronary arteries (LAD, LCx, RCA). A stenosis ≥50% was considered obstructive and a FFR abnormal if ≤0.8. All patients underwent a dynamic rest/stress 99m Tc-sestamibi CZT-SPECT and 15 O-water PET for MBF and MFR calculation. Net retention kinetic modeling was applied to SPECT data to estimate global uptake values, and MBF was derived using Leppo correction. Ischemia by PET and CZT-SPECT was considered present if MFR was lower than 2 and 2.1, respectively., Results: CZT-SPECT yielded higher stress and rest MBF compared to PET for global and LAD and LCx territories, but not in RCA territory. MFR was similar in global and each vessel territory for both modalities. The sensitivity, specificity, accuracy, positive and negative predictive value of CZT-SPECT were, respectively, 83.3, 95.8, 93.3, 100 and 85.7% for the detection of ischemia and 58.3, 84.6, 81.1, 36.8 and 93% for the detection of hemodynamically significant stenosis (FFR ≤ 0.8)., Conclusions: Dynamic 99m Tc-sestamibi CZT-SPECT was technically feasible and provided similar MFR compared to 15 O-water PET and high diagnostic value for detecting impaired MFR and abnormal FFR in patients with stable CAD.

Aim: Our aim was (1) to evaluate the prevalence of steatosis in lymphoma patients and its evolution during treatment; (2) to evaluate the impact of hepatic steatosis on 18 F-FDG liver uptake; and (3) to study how hepatic steatosis affects the Deauville score (DS) for discriminating between responders and non-responders., Methods: Over a 1-year period, 358 PET scans from 227 patients [122 diffuse large B cell lymphoma (DLBCL), 57 Hodgkin lymphoma (HL) and 48 Follicular lymphoma (FL)] referred for baseline (n = 143), interim (n = 79) and end-of-treatment (EoT, n = 136) PET scans were reviewed. Steatosis was diagnosed on the unenhanced CT part of PET/CT examinations using a cut-off value of 42 Hounsfield units (HU). EARL-compliant SUL max were recorded on the liver and the tumour target lesion. DS were then computed., Results: Prevalence of steatosis at baseline, interim and EoT PET was 15/143 (10.5%), 6/79 (7.6%) and 16/136 (11.8%), respectively (p = 0.62).Ten out of 27 steatotic patients (37.0%) displayed a steatotic liver on all examinations. Six patients (22.2%) had a disappearance of hepatic steatosis during their time-course of treatment. Only one patient developed steatosis during his course of treatment. Liver SUL max values were significantly lower in the steatosis versus non-steatotic groups of patients for interim (1.66 ± 0.36 versus 2.15 ± 0.27) and EoT (1.67 ± 0.29 versus 2.17 ± 0.30) PET. CT density was found to be an independent factor that correlated with liver SUL max , while BMI, blood glucose level and the type of chemotherapy regimen were not. Using a method based on this correlation to correct liver SUL max , all DS4 steatotic patients on interim (n = 1) and EoT (n = 2) PET moved to DS3., Conclusions: Steatosis is actually a theoretical but not practical issue in most patients but should be recognised and corrected in appropriate cases, namely, for those patients scored DS4 with a percentage difference between the target lesion and the liver background lower than 30%.