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Purpose We investigated whether artificial intelligence (AI)-based denoising halves PET acquisition time in digital PET/CT. Methods One hundred ninety-five patients referred for [18F]FDG PET/CT were prospectively included. Body PET acquisitions were performed in list mode. Original “PET90” (90 s/bed position) was compared to reconstructed ½-duration PET (45 s/bed position) with and without AI-denoising, “PET45AI and PET45”. Denoising was performed by SubtlePET™ using deep convolutional neural networks. Visual global image quality (IQ) 3-point scores and lesion detectability were evaluated. Lesion maximal and peak standardized uptake values using lean body mass (SULmax and SULpeak), metabolic volumes (MV), and liver SULmean were measured, including both standard and EARL1 (European Association of Nuclear Medicine Research Ltd) compliant SUL. Lesion-to-liver SUL ratios (LLR) and liver coefficients of variation (CVliv) were calculated. Results PET45 showed mediocre IQ (scored poor in 8% and moderate in 68%) and lesion concordance rate with PET90 (88.7%). In PET45AI, IQ scores were similar to PET90 (P = 0.80), good in 92% and moderate in 8% for both. The lesion concordance rate between PET90 and PET45AI was 836/856 (97.7%), with 7 lesions (0.8%) only detected in PET90 and 13 (1.5%) exclusively in PET45AI. Lesion EARL1 SULpeak was not significantly different between both PET (P = 0.09). Lesion standard SULpeak, standard and EARL1 SULmax, LLR and CVliv were lower in PET45AI than in PET90 (P mean were higher (P mean (ICC ≥ 0.87). Conclusion AI allows [18F]FDG PET duration in digital PET/CT to be halved, while restoring degraded ½-duration PET image quality. Future multicentric studies, including other PET radiopharmaceuticals, are warranted.

Background Early reports show the unequal effect the COVID-19 pandemic might have on men versus women engaged in medical research. Purpose To investigate whether the COVID-19 pandemic has had an impact on scientific publishing by female physicians in medical imaging. Materials and Methods The authors conducted a descriptive bibliometric analysis of the gender of the first and last authors of manuscripts submitted to the top 50 medical imaging journals from March to May 2020 (n = 2480) compared with the same period of the year in 2018 (n = 2238) and 2019 (n = 2355). Manuscript title, date of submission, first and last names of the first and last authors, journal impact factor, and author country of provenance were recorded. The Gender-API software was used to determine author gender. Statistical analysis comprised χ2 tests and multivariable logistic regression. Results Percentages of women listed as first and last authors were 31.6% (1172 of 3711 articles) and 19.3% (717 of 3711 articles), respectively, in 2018-2019 versus 32.3% (725 of 2248 articles) and 20.7% (465 of 2248 articles) in 2020 (P = .61 and P = .21, respectively). For COVID-19-related articles, 35.2% (89 of 253 articles) of first authors and 20.6% (52 of 253 articles) of last authors were women. No associations were found between first- and last-author gender, year of publication, and region of provenance. First and last authorship of high-ranking articles was not in favor of North American women whatever the year (odds ratio [OR], 0.79 [P = .05] and 0.72 [P = .02], respectively). Higher rates of female last authorship of high-ranking articles were observed in Europe (P = .003) and of female first authorship of low-ranking publications in Asia in 2020 (OR, 1.38; 95% CI: 0.98, 1.92; P = .06). Female first and last authorship of COVID-19-related articles was overrepresented for lowest-rank publications (P = .02 and P = .01, respectively). Conclusion One in three first authors and one in five last authors were women in 2018-2019 and 2020, respectively. Although the first 2020 lockdown did not diminish the quantity of women-authored publications, the impact on the quality was variable. ©RSNA, 2021 See also the editorial by Robbins and Khosa in this issue.

We investigated whether artificial intelligence (AI)-based denoising halves PET acquisition time in digital PET/CT.One hundred ninety-five patients referred for [PET45 showed mediocre IQ (scored poor in 8% and moderate in 68%) and lesion concordance rate with PET90 (88.7%). In PET45AI, IQ scores were similar to PET90 (P = 0.80), good in 92% and moderate in 8% for both. The lesion concordance rate between PET90 and PET45AI was 836/856 (97.7%), with 7 lesions (0.8%) only detected in PET90 and 13 (1.5%) exclusively in PET45AI. Lesion EARLAI allows [

Spirometric gating devices (SGDs) can measure the respiratory signal with high temporal resolution and accuracy. The primary objective of this study was to assess the feasibility and tolerance of a gated lung PET/CT acquisition using an SGD. The secondary objective was to compare the technical quality, accuracy, and interoperability of the SGD with that of a standard respiratory gating device, Real-Time Position Management (RPM), based on measurement of vertical thoracoabdominal displacement. Methods: A prospective phase I monocentric clinical study was performed on patients undergoing 18F-FDG PET/CT for assessment of a solitary lung nodule, staging of lung malignancy, or planning of radiotherapy. After whole-body PET/CT, a centered gated acquisition of both PET and CT was simultaneously obtained with the SGD and RPM during normal breathing. Results: Of the 46 patients who were included, 6 were prematurely excluded (1 because of hyperglycemia and 5 because of distant metastases revealed by whole-body PET/CT, leading to an unjustified extra gated acquisition). No serious adverse events were observed. Of the 40 remaining patients, the gated acquisition was prematurely stopped in 1 patient because of mask discomfort (2.5%; confidence interval [CI], 0.1%-13.2%). This event was considered patient tolerance failure. The SGD generated accurately gated PET/CT images, with more than 95% of the breathing cycle detected and high temporal resolution, in 34 of the 39 patients (87.2%; 95% CI, 60.0%-100.0%) and failed to generate a biologic tumor volume in 1 of 21 patients with increased 18F-FDG uptake (4.8%; 95% CI, 0.1%-26.5%). The quality and accuracy of respiratory signal detection and synchronization were significantly better than those obtained with RPM (P < 0.05). Conclusion: This trial supports the use of an SGD for gated lung PET/CT because of its high patient tolerance and accuracy. Although this technique seems to technically outperform RPM for gated PET/CT, further assessment of its superiority and the clinical benefit is warranted. We believe that this technique could be used as a gold standard to develop innovative approaches to eliminate respiration-induced blurring artifacts.

Background: New digital versus analogic PET has higher temporal resolution and more stable count rate, potentially limiting the degradation of PET image quality in larger patients. We wanted to describe the influence of patient’s body habitus on [18F]FDG PET image quality primary in digital PET/CT and analogic PET/CT.Results:We studied retrospectively the relation between patient’s weight, BMI, fatty massand PET image quality, described by the coefficient of variance in the liver (CVliv) and visually.177 unique patient exams on digital PET/CT (weight 35-127 kg; BMI 15-44 kg/m2) were performed with 2 protocols (protocol 1: N=52: 3MBq (0,08mCi)/kg [18F]FDG; 2minutes/bed position; 2iterations10subsets; 2mm diameter voxels and protocol 2: N=125: 4MBq (0,11mCi) /kg [18F]FDG; 1min/bed position; 4iterations4subsets; 2mm voxels).74 unique patient exams were analyzed on analogic PET/CT (weight 38-130 kg; BMI 14-52 kg/m2; with one protocol: 4MBq (0,11mCi)/kg [18F]FDG; 2min40sec/bedposition for BMIliv with weight, BMI, fatty mass (p£0.009) and male sex (p£0,03) for both camera’s, with good fit in CVliv versus weight model on digital PET/CT (R2 up to 0.62). 4MBq (0,11mCi) protocol on digital PET/CT versus analogic PET/CT obtained lower CVliv on digital PET/CT in patients liv increased similarly with weight for both protocols, up to 26% [95% Confidence Interval 2-56%] for ³90 kg versus liv values were lower in 4MBq (0,11mCi) protocol 2.Also visually PET image quality decreased with habitus on each camera (p£0.001) and was lower in females on digital PET/CT only (p=0,04).Conclusions:[18F]FDG PET image quality decreases with weight and enlarging body habitus on digital and analogic PET/CT imposing further optimization and harmonization also in digital PET/CT. This is important for clinical routine, but also (multicentric) research and development of artificial intelligence software.

18FDG PET-CT is useful for early and differential diagnosis of dementia. ASL-MRI seems an attractive alternative. Visual agreement was calculated in 21 brain regions bilaterally in 9/11 patients with suspected early-stage dementia, excluding 2 patients due to ASL-MRI motion artefacts. Overall gross agreement was almost perfect and identical between and within modalities (κ=0.85-0.86, p

Spirometric gating devices (SGDs) can measure the respiratory signal with high temporal resolution and accuracy. The primary objective of this study was to assess the feasibility and tolerance of a gated lung PET/CT acquisition using an SGD. The secondary objective was to compare the technical quality, accuracy, and interoperability of the SGD with that of a standard respiratory gating device, Real-Time Position Management (RPM), based on measurement of vertical thoracoabdominal displacement.

A 37-year-old woman with pheochromocytoma underwent presurgical FDG PET/CT. Despite her usual antiadrenergic medication consisting in 25 mg of carvedilol, PET/CT demonstrated intense and widespread FDG uptake in brown adipose tissue (BAT). No BAT FDG uptake was detectable on a repeated examination after specific preparation consisting in 40 mg propranolol and 5 mg diazepam. We therefore recommend this propranolol-diazepam preparation in patients with pheochromocytoma referred for PET/CT. Carvedilol-classically prescribed to alleviate effects of adrenergic overstimulation-seems ineffective on BAT. This observation questions the benefit of carvedilol to reduce β3-adrenoreceptor-mediated effects, not only in BAT, but also in other tissues.

Vemurafenib improves the management of advanced melanoma due to selective inhibition of the mutated BRAF V600E kinase. FDG-PET-CT is a tool for the evaluation of the biologic impact of inhibiting mutant BRAF. With vemurafenib at day 15, all the patients had at least partial metabolic response. Reductions in uptake correlate with longer progression free survival. In this case, incomplete information provided by the patient led to the performance of his third PET 85 hours after the introduction of vemurafenib. This early case of complete metabolic response suggests that FDG-PET-CT is a useful marker of early biologic response to vemurafenib.

18FDG PET-CT is useful for early and differential diagnosis of dementia. ASL-MRI seems an attractive alternative. Visual agreement was calculated in 21 brain regions bilaterally in 9/11 patients with suspected early-stage dementia, excluding 2 patients due to ASL-MRI motion artefacts. Overall gross agreement was almost perfect and identical between and within modalities (κ=0.85-0.86, p0.05). Intermodality regional agreement was variable, moderate (κ=0,56 in posterior cingulate) to perfect (including in precuneus), not different from intramodality agreement. Diagnostic accuracy was 5/9 (56%) for ASL-MRI and 7/9 (78%) for FDG PETCT. (p=0.31). Clinical experience and optimisation may further improve ASL-MRI's performance.

This 65 year-old woman, 1 month postoperative after maxillary sinus carcinoma (pT4N0cM0) excision and reconstruction, presented with significant left facial clear fluid wound leakage. A salivary or cerebrospinal leakage was suspected. Fluid analysis, CT, and MRI were noncontributory. Dynamic salivary scintigraphy with SPECT-CT allowed for the detection and localization of the leakage from the left parotid gland. Radioactive dose rate of the wound bandage was 50 μSv/h compared with 0.05 μSv/h for background and confirmed the diagnosis. Left total parotidectomy resulted in resolution.

Purpose: Respiratory motion is a source of artifacts that reduce image quality in PET. Four dimensional (4D) PET/CT is one approach to overcome this problem. Existing techniques to limiting the effects of respiratory motions are based on prospective phase binning which requires a long acquisition duration (15–25 min). This time is uncomfortable for the patients and limits the clinical exploitation of 4D PET/CT. In this work, the authors evaluated an existing method and an alternative retrospective binning method to reduce the acquisition duration of 4D PET/CT. Methods: The authors studied an existing mixed-amplitude binning (MAB) method and an alternative binning method by mixed-phases (MPhB). Before implementing MPhB, they analyzed the regularity of the breathing patterns in patients. They studied the breathing signal drift and missing CT slices that could be challenging for implementing MAB. They compared the performance of MAB and MPhB with current binning methods to measure the maximum uptake, internal volume, and maximal range of tumor motion. Results: MPhB can be implemented depending on an optimal phase (in average, the exhalation peak phase −4.1% of the entire breathing cycle duration). Signal drift of patients was in average 35% relative to the breathing amplitude. Even after correcting this drift,more » MAB was feasible in 4D CT for only 64% of patients. No significant differences appeared between the different binning methods to measure the maximum uptake, internal volume, and maximal range of tumor motion. The authors also determined the inaccuracies of MAB and MPhB to measure the maximum amplitude of tumor motion with three bins (less than 3 mm for movement inferior to 12 mm, up to 6.4 mm for a 21 mm movement). Conclusions: The authors proposed an alternative binning method by mixed-phase binning that halves the acquisition duration of 4D PET/CT. Mixed-amplitude binning was challenging because of signal drift and missing CT slices. They showed that more than three bins were necessary for a more accurate measurement of the maximum amplitude of the tumor motion. However, the current 4D-CT technology limits the increase of the number of bins in 4D PET/CT because of missing CT slices. One can reconstruct 4D PET images with more bins but without attenuation/scatter correction.« less