PET FDG CT is useful for giant-cell arteritis with isolated cough.

Giant cell arteritis (GCA) is a chronic vasculitis of large- and medium-sized vessels. The most frequent symptoms are temporal headaches, scalp tenderness, jaw claudication and polymyalgia rheumatica in 35% of patients. Atypical presentation with dry cough is very rare and could be isolated making the diagnosis difficult. Initial imaging including PET-CT could be helpful. Literature review yielded 13 case reports with available data and one case series which focused on cough and which were all be included in this study. Most of the cases included males (n = 8), with mostly isolated cough or associated to fever and weight loss. Angio-CT of aortic wall was mostly normal, whereas FDG PET-CT showed in all available cases abnormal arterial thoracic uptake. Temporal artery biopsy was almost suggestive of GCA in all available cases. Cough was steroid responsive usually within few days in all cases without any need of combined therapy. Giant cell arteritis is the most common large-vessel vasculitis over the age of 50 in western countries. Isolated dry cough is extremely rare and encountered in less than 5% of cases.

Influence of key histological characteristics on 18F-fluorodeoxyglucose /18F-choline positron emission tomography positivity in hepatocellular carcinoma: A machine learning study.

Purpose: To determine the characteristics influence of key histological on 18F-fluorodeoxyglucose (18F-FDG) and 18F-choline positron emission tomography (PET) positivity in hepatocellular carcinoma (HCC). Materials and methods: The 18F-FDG/18F-choline PET imaging findings of 103 histologically proven HCCs (from 62 patients, of which 47 underwent hepatectomy and 15 received liver transplantation) were retrospectively examined to assess the following key histological parameters: Grade, capsule, microvascular invasion (mVI), macrovascular invasion (MVI), and necrosis. Using a ratio of 70/30 for training and testing sets, respectively, a penalized classification model (Elastic Net) was trained using 100 repeated cross-validation procedures (10-fold cross-validation for hyperparameter optimization). The contribution of each histological parameter to the PET positivity was determined using the Shapley Additive Explanations method. Receiver operating characteristic curves with and without dimensionality reduction were finally estimated and compared. Results: Among the five key histological characteristics of HCC (Grade, capsule, mVI, MVI, and necrosis), mVI and tumor Grade (I-III) showed the highest relevance and robustness in explaining HCC uptake of 18F-FDG and 18F-choline. MVI and necrosis status both showed high instability in outcome predictions. Tumor capsule had a minimal influence on the model predictions. On retaining only mVI and Grades I-III for the final analysis, the area under the receiver operating characteristic (ROC) curve values were maintained (0.68 vs. 0.63, 0.65 vs. 0.64, and 0.65 vs. 0.64 for 18F-FDG, 18F-choline, and their combination, respectively). Conclusion: 18F-FDG/18F-choline PET positivity appears driven by both the Grade and mVI components in HCC. Consideration of the tumor microenvironment will likely be necessary to improve our understanding of multitracer PET positivity.

Is 18 F-FDG/ 18 F-Choline Dual-Tracer PET Behavior a Surrogate of Tumor Differentiation in Hepatocellular Carcinoma : A Tertiary Center Dedicated Study.

BACKGROUND: In hepatocellular carcinoma (HCC) setting, 18 F-FDG and 18 F-choline PET/CT radiotracers are classically considered surrogates of the degree of differentiation, a strong predictor of disease recurrence after curative treatment. Because the corresponding level of evidence has never been assessed as primary end point, the aim of this retrospective study was to specifically assess the relevance of 18 F-FDG combined to 18 F-choline PET imaging as a surrogate of tumor differentiation in HCC. PATIENTS AND METHODS: A total of 49 histologically proven HCCs (46 patients treated by surgery or liver transplantation) with available baseline 18 F-FDG and 18 F-choline PET/CT, dedicated liver contrast-enhanced CT scan, and histological key features were retrospectively reviewed. Hepatocellular carcinoma tumors with well, moderately, and poorly differentiation (grades I, II, and III of the World Health Organization classification) were compared on their PET findings (double-blinded visual analysis and 8 usual semiquantitative metrics) by using nonparametric Kruskal-Wallis analyses of variance. In the case of statistical significance, pairwise post hoc tests with family-wise error rate adjustment were performed. RESULTS: No statistical difference between the grades was observed for any of the patients' or lesions' characteristics ( P > 0.05), except for the macrovascular invasion between the grades I and II (adjusted P = 0.03). None of the PET findings showed statistical difference between the grades, except the tumor-to-background ratio of 18 F-FDG, higher for the grade III compared with grades I (adjusted P = 0.02) and II (adjusted P = 0.01). For less than one third of cases (14 lesions; 28.5%), the regional uptake was judged visually heterogeneous, but none of the related semiquantitative PET metrics were statistically discriminant ( P > 0.05). CONCLUSIONS: Contrary to a common belief, 18 F-FDG/ 18 F-choline dual-tracer PET behavior is not a relevant surrogate of tumor differentiation in HCC. Future multitracer PET studies are mandatory to refine our knowledges of their deep biological meaning in this field.

Towards refining the utility of dual (18F-FDG / 18F-Choline) PET/CT for the management of hepatocellular carcinoma: a tertiary center study.

BACKGROUND: The role of positron emission tomography/computed tomography (PET/CT) in hepatocellular carcinoma (HCC) management is not clearly defined. Our objective was to analyze the utility of dual-PET/CT (18F-FDG + 18F-Choline) imaging findings on the BCLC staging and treatment decision for HCC patients. METHODS: Between January 2011 and April 2019, 168 consecutive HCC patients with available baseline dual-PET/CT imaging data were retrospectively analyzed. To identify potential refinement criteria for surgically-treated patients, survival Kaplan-Meier curves of various standard-of-care and dual-PET/CT baseline parameters were estimated. Finally, multivariate cox proportional hazard ratios of the most relevant clinico-biological and/or PET parameters were estimated. RESULTS: Dual-PET/CT findings increased the score of BCLC staging in 21 (12.5%) cases. In 24.4% (N.=41) of patients, the treatment strategy was modified by the PET findings. Combining AFP levels at a threshold of 10 ng/mL with 18F-FDG or 18F-Choline N status significantly impacted DFS (P<0.05). In particular, the combined criteria of the N+ status assessed by 18F-Choline with AFP threshold of 10 ng/mL provided a highly predictive composite parameter for estimation of DFS according to multivariate analysis (HR=10.6, P<0.05). CONCLUSIONS: The 18F-Choline / AFP composite parameter appears promising, and further prospective studies are mandatory to validate its oncological impact.

18F-FDG PET molecular imaging: A relevant tool to investigate chronic inflammatory rheumatisms in clinical practice?

18F-Labeled Fluorodeoxyglucose-Positron Emission Tomography (18F-FDG PET) is a molecular imaging tool commonly used in practice for the assessment of many cancers. Thanks to its properties, its use has been progressively extended to numerous inflammatory conditions, including chronic inflammatory rheumatism (CIR) such as rheumatoid arthritis (RA), spondylarthritis (SpAs) and polymyalgia rheumatica (PMR). 18F-FDG PET is currently not recommended for the diagnostic of CIRs. However, this whole-body imaging tool has emerged in clinical practice, providing a general overview of systemic involvement occurring in CIRs. Numerous studies have highlighted the capacity of 18F-FDG PET to detect articular and extra articular involvements in RA and PMR. However, the lack of specificity of 18F-FDG limits its use for diagnosis purpose. Finally, the key question is the definition of the best way to integrate this whole-body imaging tool in the patient's management workflow.

Isotopic Radiolabeling of Crizotinib with Fluorine-18 for In Vivo Pet Imaging.

Crizotinib is a tyrosine kinase inhibitor approved for the treatment of non-small-cell lung cancer, but it is inefficient on brain metastases. Crizotinib is a substrate of the P-glycoprotein, and non-invasive nuclear imaging can be used to assess the brain penetration of crizotinib. Positron emission tomography (PET) imaging using fluorine-18-labeled crizotinib would be a powerful tool for investigating new strategies to enhance the brain distribution of crizotinib. We have synthesized a spirocyclic hypervalent iodine precursor for the isotopic labeling of crizotinib in a 2.4% yield. Because crizotinib is an enantiomerically pure drug, a chiral separation was performed to afford the (R)-precursor. A two-step radiolabeling process was optimized and automated using the racemic precursor to afford [18F](R,S)-crizotinib in 15 ± 2 radiochemical yield and 103 ± 18 GBq/µmol molar activity. The same radiolabeling process was applied to the (R)-precursor to afford [18F](R)-crizotinib with comparable results. As a proof-of-concept, PET was realized in a single non-human primate to demonstrate the feasibility of [18F](R)-crizotinib in in vivo imaging. Whole-body PET highlighted the elimination routes of crizotinib with negligible penetration in the brain (SUVmean = 0.1). This proof-of-concept paves the way for further studies using [18F](R)-crizotinib to enhance its brain penetration depending on the P-glycoprotein function.

18F-FDG /18F-Choline Dual-Tracer PET Behavior and Tumor Differentiation in HepatoCellular Carcinoma. A Systematic Review.

Background: Post-operative recurrence remains the strongest prognostic factor of resected hepatocellular carcinoma (HCC), making the accurate selection of patients with curable HCC a crucial issue. PET imaging combining both 18F-FDG and fatty acid synthase (FAS) radiotracers-such as Choline-has shown its interest for the initial staging and therapeutic management of patients with HCC, but its use is still not consensual. Importantly, the very first dual-tracer PET studies suggested 18F-FDG/FAS PET behavior be linked to the degree of differentiation of HCC, a major predictive factor of post-operative recurrence. Although this key molecular imaging concept may impact how dual-tracer PET will be used in early-stage HCC, its level of evidence remains largely unexplored. In this study, we conducted a systematic review of the available evidence-based data to clarify the relevance of dual 18F-FDG/18F-Choline PET in characterizing the degree of differentiation of HCC tumors. Methods: A systematic search of the PubMed/Medline and Embase databases was performed up to November 2021. A systematic review of the dual-tracer 18F-FDG/18F-Choline PET behavior of histology-proven HCC according to their degree of differentiation was conducted. The overall quality of the included studies was critically assessed based on the STROBE guidelines. Information on study date, design, patient cohort characteristics, grade of differentiation of HCC tumors, and the dual-tracer PET behavior per HCC was independently extracted and summarized. Results: From 440 records initially available, 6 full-text articles (99 histology-proven HCC) provided dual-tracer 18F-FDG/18F-Choline PET behavior per HCC tumor grade were included in the systematic review. Based on our analysis, 43/99 HCCs were reported to be well-differentiated, and 56/99 HCCs were reported to be less-differentiated tumors. In the well-differentiated subgroup, more than half were exclusively positive for 18F-Choline (51%), whereas 39% were positive for both 18F-FDG and 18F-Choline. In the less-differentiated subgroup, 37% of HCC patients were positive exclusively for FDG, 36% were positive for both 18F-FDG and 18F-Choline, and 25% were positive exclusively for 18F-Choline. Conclusion: The 18F-FDG/18F-Choline dual-tracer PET behavior of uptake shows high overlap between well- and less differentiated HCC, making the characterization of tumors challenging based on such PET combination alone. Given our growing knowledge of the molecular complexity of HCC, further studies are necessary to refine our understanding of radiotracers' behavior in this field and improve the usefulness of PET imaging in the clinical decision process of HCC.

Renal involvement of lymphomas proven by kidney biopsy: report of 10 cases from a tertiary care center and comparison with the literature.

Lymphomas localized in the kidney are a rare entity that may be challenging to diagnose. We analyzed data from 10 patients with renal involvement of lymphoma diagnosed between 2009 and 2019 on fine needle biopsy from our tertiary center, and compared these with findings of 160 cases reported in the literature. Diffuse large B-cell lymphoma was the main histology subtype (40 and 38% in our sample and in the literature, respectively), followed by low-grade B-cell lymphomas, mostly from the marginal zone (MZ). Altogether, 106 patients had urological inaugural symptoms and 64 had general symptoms. Patients with urological presentation more often had renal masses than diffuse infiltration (p < 0.001), unilateral tumors (p = 0.0036) and low-grade B-cell lymphomas (17 vs 6%, p = 0.043). In both groups, nearly one-fourth of patients had diffuse (stage IV) lymphomas. Overall survival did not differ by the presence of urological/systemic symptoms, stage or aggressive lymphoma status. Notably, 3 of 10 patients from our series had MZ lymphomas associated with primary Sjögren syndrome revealed by acute kidney injury, including one where the autoimmune disease was detected. Lymphoproliferative disorders localized in the kidney are a challenging condition that can lead to detection of aggressive or diffuse lymphomas.

Features of non-Hodgkin's lymphoma diagnosed in minor salivary gland biopsies from primary Sjögren's syndrome patients.

OBJECTIVE: To evaluate the contribution of minor salivary gland biopsy (mSGB) histology in diagnosing primary SS (pSS)-associated non-Hodgkin B-cell lymphoma (NHL). METHODS: pSS patients with mSGB at NHL diagnosis were included. RESULTS: Among the 24 patients (92.3% female, mean age 61.3 years) with an mSGB at NHL diagnosis, 13 (54.2%) had mSGB histology-revealed NHL (mSGB+); it was the only site enabling NHL diagnosis in 10/13 (76.9%) patients. Mucosa-associated lymphoid tissue (MALT) lymphoma was found in 23/24 (95.8%) patients; 100% of mSGB+ identified MALT lymphomas. pSS and lymphoma characteristics were comparable for mSGB+ and mSGB- patients. Eight (61.5%) of the 13 mSGB+ patients and all 11 mSGB- patients were treated for lymphoma. Between diagnosis and 1 year of follow-up, the ESSDAI without the NHL item remained stable (7.4 vs 5.0; P = 0.33) for the five untreated patients, while it decreased significantly for the 19 treated patients (15.8 vs 5.1; P = 0.004). CONCLUSION: For pSS patients with suspected NHL, mSGB histology enabled NHL diagnosis in half of them, MALT was found in 95.8% and all mSGB+ were MALT lymphomas, thereby avoiding more invasive biopsy. Our results suggest that mSGB should be obtained at pSS diagnosis and repeated during follow-up when NHL is suspected.

Fully Integrated Quantitative Multiparametric Analysis of Non-Small Cell Lung Cancer at 3-T PET/MRI: Toward One-Stop-Shop Tumor Biological Characterization at the Supervoxel Level.

INTRODUCTION: The aim of this study was to study the feasibility of a fully integrated multiparametric imaging framework to characterize non-small cell lung cancer (NSCLC) at 3-T PET/MRI. PATIENTS AND METHODS: An 18F-FDG PET/MRI multiparametric imaging framework was developed and prospectively applied to 11 biopsy-proven NSCLC patients. For each tumor, 12 parametric maps were generated, including PET full kinetic modeling, apparent diffusion coefficient, T1/T2 relaxation times, and DCE full kinetic modeling. Gaussian mixture model-based clustering was applied at the whole data set level to define supervoxels of similar multidimensional PET/MRI behaviors. Taking the multidimensional voxel behaviors as input and the supervoxel class as output, machine learning procedure was finally trained and validated voxelwise to reveal the dominant PET/MRI characteristics of these supervoxels at the whole data set and individual tumor levels. RESULTS: The Gaussian mixture model-based clustering clustering applied at the whole data set level (17,316 voxels) found 3 main multidimensional behaviors underpinned by the 12 PET/MRI quantitative parameters. Four dominant PET/MRI parameters of clinical relevance (PET: k2, k3 and DCE: ve, vp) predicted the overall supervoxel behavior with 97% of accuracy (SD, 0.7; 10-fold cross-validation). At the individual tumor level, these dimensionality-reduced supervoxel maps showed mean discrepancy of 16.7% compared with the original ones. CONCLUSIONS: One-stop-shop PET/MRI multiparametric quantitative analysis of NSCLC is clinically feasible. Both PET and MRI parameters are useful to characterize the behavior of tumors at the supervoxel level. In the era of precision medicine, the full capabilities of PET/MRI would give further insight of the characterization of NSCLC behavior, opening new avenues toward image-based personalized medicine in this field.

Diagnostic Splenectomy: Characteristics, Pre-Operative Investigations, and Identified Pathologies for 20 Patients.

Splenectomy is indicated in cases of trauma to the spleen or hematological and immunological diseases (hereditary spherocytosis, autoimmune cytopenia). Less frequently, splenectomy is performed for diagnostic purposes to complement unsuccessful prior etiological investigations. The splenectomy remains a surgery at risk of complications and should be considered as a last-resort procedure to make the diagnosis and to be able to treat patients. We studied the medical files of 142 patients who underwent a splenectomy for any reason over a 10-year period and identified 20 diagnostic splenectomies. Diagnostic splenectomies were mainly performed to explore unexplained splenomegaly for 13 patients and fever of unknown origin for 10. The other patients had surgery for other causes (cytopenia, abdominal symptoms, suspicion of relapsing malignant hemopathies). Splenectomy contributed to the final diagnosis in 19 of 20 cases, corresponding mostly to lymphoid hemopathies (14/20). The most frequent disease was diffuse large B-cell lymphoma (8/20). Splenectomy did not reveal any infectious disease. The most relevant pre-operative procedures to aid the diagnosis were 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) and immuno-hematological examinations. Diagnostic splenectomy is useful and necessary in certain difficult diagnostic situations. Highlights: Diagnostic splenectomy is still useful in 2020 to diagnose unexplained splenomegaly or fever of unknown origin. Lymphoma was the most common final diagnosis. FDG PET/CT was the most useful tool to aid in the diagnosis.

PET Molecular Imaging: A Holistic Review of Current Practice and Emerging Perspectives for Diagnosis, Therapeutic Evaluation and Prognosis in Clinical Oncology.

PET/CT molecular imaging has been imposed in clinical oncological practice over the past 20 years, driven by its two well-grounded foundations: quantification and radiolabeled molecular probe vectorization. From basic visual interpretation to more sophisticated full kinetic modeling, PET technology provides a unique opportunity to characterize various biological processes with different levels of analysis. In clinical practice, many efforts have been made during the last two decades to standardize image analyses at the international level, but advanced metrics are still under use in practice. In parallel, the integration of PET imaging with radionuclide therapy, also known as radiolabeled theranostics, has paved the way towards highly sensitive radionuclide-based precision medicine, with major breakthroughs emerging in neuroendocrine tumors and prostate cancer. PET imaging of tumor immunity and beyond is also emerging, emphasizing the unique capabilities of PET molecular imaging to constantly adapt to emerging oncological challenges. However, these new horizons face the growing complexity of multidimensional data. In the era of precision medicine, statistical and computer sciences are currently revolutionizing image-based decision making, paving the way for more holistic cancer molecular imaging analyses at the whole-body level.

AZTEK: Adaptive zero TE k-space trajectories.

PURPOSE: Because of short signal lifetimes and respiratory motion, 3D lung MRI is still challenging today. Zero-TE (ZTE) pulse sequences offer promising solutions as they overcome the issue of short T2∗ . Nevertheless, as they rely on continuous readout gradients, the trajectories they follow in k-space are not adapted to retrospective gating and inferred motion correction. THEORY AND METHODS: We propose AZTEK (adaptive ZTE k-space trajectories), a set of 3D radial trajectories featuring three tuning parameters, to adapt the acquisition to any moving organ while keeping seamless transitions between consecutive spokes. Standard ZTE and AZTEK trajectories were compared for static and moving phantom acquisitions as well as for human thoracic imaging performed on 3 volunteers (1 healthy and 2 patients with lung cancer). RESULTS: For the static phantom, we observe comparable image qualities with standard and AZTEK trajectories. For the moving phantom, spatially coherent undersampling artifacts observed on gated images with the standard trajectory are alleviated with AZTEK. The same improvement in image quality is obtained in human, so details are more delineated in the lung with the use of the adaptive trajectory. CONCLUSION: The AZTEK technique opens the possibility for 3D dynamic ZTE lung imaging with retrospective gating. It enables us to uniformly sample the k-space for any arbitrary respiratory motion gate, while preserving static image quality, improving dynamic image quality and guaranteeing continuous readout gradient transitions between spokes, which makes it appropriate to ZTE.

18F-FDG PET and DCE kinetic modeling and their correlations in primary NSCLC: first voxel-wise correlative analysis of human simultaneous [18F]FDG PET-MRI data.

OBJECTIVES: To decipher the correlations between PET and DCE kinetic parameters in non-small-cell lung cancer (NSCLC), by using voxel-wise analysis of dynamic simultaneous [18F]FDG PET-MRI. MATERIAL AND METHODS: Fourteen treatment-naïve patients with biopsy-proven NSCLC prospectively underwent a 1-h dynamic [18F]FDG thoracic PET-MRI scan including DCE. The PET and DCE data were normalized to their corresponding T1-weighted MR morphological space, and tumors were masked semi-automatically. Voxel-wise parametric maps of PET and DCE kinetic parameters were computed by fitting the dynamic PET and DCE tumor data to the Sokoloff and Extended Tofts models respectively, by using in-house developed procedures. Curve-fitting errors were assessed by computing the relative root mean square error (rRMSE) of the estimated PET and DCE signals at the voxel level. For each tumor, Spearman correlation coefficients (rs) between all the pairs of PET and DCE kinetic parameters were estimated on a voxel-wise basis, along with their respective bootstrapped 95% confidence intervals (n = 1000 iterations). RESULTS: Curve-fitting metrics provided fit errors under 20% for almost 90% of the PET voxels (median rRMSE = 10.3, interquartile ranges IQR = 8.1; 14.3), whereas 73.3% of the DCE voxels showed fit errors under 45% (median rRMSE = 31.8%, IQR = 22.4; 46.6). The PET-PET, DCE-DCE, and PET-DCE voxel-wise correlations varied according to individual tumor behaviors. Beyond this wide variability, the PET-PET and DCE-DCE correlations were mainly high (absolute rs values > 0.7), whereas the PET-DCE correlations were mainly low to moderate (absolute rs values < 0.7). Half the tumors showed a hypometabolism with low perfused/vascularized profile, a hallmark of hypoxia, and tumor aggressiveness. CONCLUSION: A dynamic "one-stop shop" procedure applied to NSCLC is technically feasible in clinical practice. PET and DCE kinetic parameters assessed simultaneously are not highly correlated in NSCLC, and these correlations showed a wide variability among tumors and patients. These results tend to suggest that PET and DCE kinetic parameters might provide complementary information. In the future, this might make PET-MRI a unique tool to characterize the individual tumor biological behavior in NSCLC.

Diffusion-weighted Imaging Voxelwise-matched Analyses of Lung Cancer at 3.0-T PET/MRI: Reverse Phase Encoding Approach for Echo-planar Imaging Distortion Correction.

Background PET/MRI has drawn increasing interest in thoracic oncology due to the simultaneous acquisition of PET and MRI data. Geometric distortions related to diffusion-weighted imaging (DWI) limit the evaluation of voxelwise multimodal analyses. Purpose To assess the effectiveness of reverse phase encoding in correcting DWI geometric distortion for multimodal PET/MRI voxelwise lung tumor analyses. Materials and Methods In this prospective study, reverse phase encoding method was implemented with 3.0-T PET/MRI to correct geometric distortions related to DWI. The method was validated in dedicated phantom and then applied to 12 consecutive patients (mean age, 66 years ± 13 [standard deviation]; 10 men) suspected of having lung cancer who underwent fluorodeoxyglucose PET/MRI between October 2018 and April 2019. The effects on DWI-related image matching and apparent diffusion coefficient (ADC) regional map computation were assessed. Consequences on multimodal PET/MRI voxelwise lung tumor analyses were evaluated. Spearman correlation coefficients (rs) between the standardized uptake value (SUV) and ADC data corrected for distortion were computed from optimal realigned DWI PET data, along with bootstrap confidence intervals. Results Phantom results showed that in highly distorted areas, correcting the distortion significantly reduced the mean error against the ground truth (-25% ± 10.6 to -18.4% ± 12.6; P < .001) and the number of voxels with more than 20% error (from 85.3% to 31.4%). In the 12 patients, the coregistration of multimodal PET/MRI tumor data was improved by using the reverse phase encoding method (0.4%-44%). In all tumors, voxelwise correlations (rs) between ADC and SUV revealed null or weak monotonic relationships (mean rs of 0.016 ± 0.24 with none above 0.5). Conclusion Reverse phase encoding is a simple-to-implement method for improved diffusion-weighted multimodal PET/MRI voxelwise-matched analyses in lung cancer. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Colletti in this issue.

Toward radiomics for assessment of response to systemic therapies in lung cancer.

This editorial comment explains recent developments in radiomics regarding the use of quantitative imaging biomarkers to predict lung cancer sensitivity to a variety of cancer therapies. Tumor response assessment has been a crucial component guiding cancer treatment. Evaluation of treatment response was standardized and classically based on measuring changes in tumor lesion size. Recent breakthroughs in artificial intelligence pave the way for the use of radiomics in tumor response assessment. Such objective techniques would bring a remarkable transformation to conventional methods, which can be inherently subjective. Successful implementation of these technologies would allow for faster and more accurate predictions of treatment efficacy, which will be critical to the advancement of personalized medicine.

Imaging-guided precision medicine in non-resectable gastro-entero-pancreatic neuroendocrine tumors: A step-by-step approach.

The majority of gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are diagnosed at a non-resectable stage due to non-specific clinical syndromes, late manifestations from mass effects, or incidental detection of a clinically silent disease. Management strategies include curative or cytoreduction surgery, imaging-guided intervention, chemotherapy, immunotherapy, and radionuclide therapies. In this step-by-step review, we provide a structured approach for standardized reading and reporting of medical imaging studies covering content and terminology. This review explains which imaging studies should be used for different NETs and what should be reported when interpreting these studies. This standardized data collection guide should enable precision medicine for the management of patients with GEP-NETs of neuroectodermal origin: gastrointestinal-NETs (giNETs) and pancreatic NETs (pNETs). To improve outcomes from GEP-NETs, it contains a comprehensive evaluation of imaging aids for determining surgical non-resectability, and serves as a surrogate measure for tumor differentiation and proliferation, assessing the spatial and temporal heterogeneity of the tumor sites with prognostic and therapeutic implications.

Imaging-guided precision medicine in glioblastoma patients treated with immune checkpoint modulators: research trend and future directions in the field of imaging biomarkers and artificial intelligence.

Immunotherapies that employ immune checkpoint modulators (ICMs) have emerged as an effective treatment for a variety of solid cancers, as well as a paradigm shift in the treatment of cancers. Despite this breakthrough, the median survival time of glioblastoma patients has remained at about 2 years. Therefore, the safety and anti-cancer efficacy of combination therapies that include ICMs are being actively investigated. Because of the distinct mechanisms of ICMs, which restore the immune system's anti-tumor capacity, unconventional immune-related phenomena are increasingly being reported in terms of tumor response and progression, as well as adverse events. Indeed, immunotherapy response assessments for neuro-oncology (iRANO) play a central role in guiding cancer patient management and define a "wait and see strategy" for patients treated with ICMs in monotherapy with progressive disease on MRI. This article deciphers emerging research trends to ameliorate four challenges unaddressed by the iRANO criteria: (1) patient selection, (2) identification of immune-related phenomena other than pseudoprogression (i.e., hyperprogression, the abscopal effect, immune-related adverse events), (3) response assessment in combination therapies including ICM, and (4) alternatives to MRI. To this end, our article provides a structured approach for standardized selection and reporting of imaging modalities to enable the use of precision medicine by deciphering the characteristics of the tumor and its immune environment. Emerging preclinical or clinical innovations are also discussed as future directions such as immune-specific targeting and implementation of artificial intelligence algorithms.