Metabolic Imaging Research Articles

Deuterium MR spectroscopy: potential applications in oncology research.

Metabolic imaging in clinical practice has long relied on PET with fluorodeoxyglucose (FDG), a radioactive tracer. However, this conventional method presents inherent limitations such as exposure to ionizing radiation and potential diagnostic uncertainties, particularly in organs with heightened glucose uptake like the brain. This review underscores the transformative potential of traditional deuterium MR spectroscopy (MRS) when integrated with gradient techniques, culminating in an advanced metabolic imaging modality known as deuterium MRI (DMRI). While recent advancements in hyperpolarized MRS hold promise for metabolic analysis, their widespread clinical usage is hindered by cost constraints and the availability of hyperpolarizer devices or facilities. DMRI, also denoted as deuterium metabolic imaging (DMI), represents a pioneering, single-shot, and noninvasive paradigm that fuses conventional MRS with nonradioactive deuterium-labelled substrates. Extensively tested in animal models and patient cohorts, particularly in cases of brain tumours, DMI's standout feature lies in its seamless integration into standard clinical MRI scanners, necessitating only minor adjustments such as radiofrequency coil tuning to the deuterium frequency. DMRI emerges as a versatile tool for quantifying crucial metabolites in clinical oncology, including glucose, lactate, glutamate, glutamine, and characterizing IDH mutations. Its potential applications in this domain are broad, spanning diagnostic profiling, treatment response monitoring, and the identification of novel therapeutic targets across diverse cancer subtypes.

Quantitative 17 O MRSI of myocardial oxygen metabolic rate, blood flow, and oxygen extraction fraction under normal and high workload conditions.

The heart is a highly aerobic organ consuming most of the oxygen the body in supporting heart function. Quantitative imaging of myocardial oxygen metabolism and perfusion is essential for studying cardiac physiopathology in vivo. Here, we report a new imaging method that can simultaneously assess myocardial oxygen metabolism and blood flow in the rat heart. This novel method is based on the 17 O-MRSI combined with brief inhalation of 17 O-isotope labeled oxygen gas for quantitative imaging of myocardial metabolic rate of oxygen consumption (MVO2 ), myocardial blood flow (MBF), and oxygen extraction fraction (OEF). We demonstrate this imaging method under basal and high workload conditions in rat hearts at 9.4 T. We show that this 17 O MRSI-based approach can directly measure and image MVO2 (1.35-4.06 μmol/g/min), MBF (0.49-1.38 mL/g/min), and OEF (0.33-0.44) in the heart of anesthetized rat under basal and high workload (21.6 × 103 -56.7 × 103 mmHg • bpm) conditions. Under high workload condition, MVO2 and MBF values in healthy rats approximately doubled, whereas OEF remained unchanged, indicating a strong coupling between myocardial oxygen metabolic demand and supply through blood perfusion. The 17 O-MRSI method has been used to simultaneously image the myocardial metabolic rate of oxygen consumption, blood flow, and oxygen extraction fraction in small animal hearts, which are sensitive to the physiological changes induced by high workload. This approach could provide comprehensive measures that are critical for studying myocardial function in normal and diseased states and has a potential for translation.

Metabolic brain imaging with glucosamine CEST MRI: in vivo characterization and first insights

The utility of chemical exchange saturation transfer (CEST) MRI for monitoring the uptake of glucosamine (GlcN), a safe dietary supplement, has been previously demonstrated in detecting breast cancer in both murine and human subjects. Here, we studied and characterized the detectability of GlcN uptake and metabolism in the brain. Following intravenous GlcN administration in mice, CEST brain signals calculated by magnetization transfer ratio asymmetry (MTRasym) analysis, were significantly elevated, mainly in the cortex, hippocampus, and thalamus. The in vivo contrast remained stable during 40 min of examination, which can be attributed to GlcN uptake and its metabolic products accumulation as confirmed using 13C NMR spectroscopic studies of brain extracts. A Lorentzian multi-pool fitting analysis revealed an increase in the hydroxyl, amide, and relayed nuclear Overhauser effect (rNOE) signal components after GlcN treatment. With its ability to cross the blood-brain barrier (BBB), the GlcN CEST technique has the potential to serve as a metabolic biomarker for the diagnosis and monitoring various brain disorders.

Mechanism-aware and multimodal AI: beyond model-agnostic interpretation

Artificial intelligence (AI) is widely used for exploiting multimodal biomedical data, with increasingly accurate predictions and model-agnostic interpretations, which are however also agnostic to biological mechanisms. Combining metabolic modelling, ‘omics, and imaging data via multimodal AI can generate predictions that can be interpreted mechanistically and transparently, therefore with significantly higher therapeutic potential.

Characteristic early changes of Glu and Cho in brain regions affected by different types of subjective cognitive decline and their clinical significance.

To discuss the early changes of Glu and Cho in the affected areas of different types of subjective cognitive decline, including amnestic MCI (aMCl), non-amnestic MCI (naMCI) and vascular cognitive impairment no dementia (VCIND), using Proton Magnetic Resonance Spectroscopy (1H-MRS) technology. Routine head MRI and lH-MRS examinations were performed on 50 clearly diagnosed aMCI patients, 44 naMCI patients, 44 VCIND patients, and 44 elderly individuals with normal cognitive function. Measure the volume of the patient bilateral hippocampus. Using the bilateral hippocampus, left posterior cingulate gyrus (PCG), and frontal lobe as regions of interest, the scope under the peak of N-acetylaspartate (NAA), choline complex (Cho), glutamate (Glu), Metabolic Images (mI), and creatine (Cr) was tested. Perform a correlation analysis between the NAA/Cho/Cr values of the VCIND group and the MoCA score. All experimental subjects were right-handed. The NAACr values in both hippocampus of the VCIND were greatly lower than those in control (P < .05). The NAA/Cr values on both sides of the VCIND were correlated with the MoCA score (P < .05). The NAA/Cr values in the LHp and PCG of subjects in the aMCI and naMCI groups were lower than those in the NC group (P < .05). The NAA/Cr values in the left frontal lobe of the aMCI and naMCI showed no obvious decrease compared to the NC. The Glu/Cr of subjects in the aMCI was lower in the left PCG than those in the naMCI and NC (P < .05). The discrepancy between the naMCI and the NC was P > .05. In the LHp and frontal lobe, in contrast with the naMCI and NC, the mI/Cr values in the LHp and PCG of subjects in the aMCI were higher (P < .05). In the left frontal lobe, relative to the aMCI and NC, the mI/Cr values in the naMCI were higher (P < .05). The changes in the concentration of 1H-MRS metabolites in the hippocampus can indicate the presence of hippocampal neuronal damage before morphological changes occur in the hippocampus. 1H-MRS NAA/Cr can reflect the cognitive function changes of patients to a certain extent. There are regional differences in mI and Glu metabolism in the brain between aMCI and naMCI groups. 1H-MRS provides an effective basis for clinical differentiation between aMCI and naMCI.

Radiomic Analysis for Human Papillomavirus Assessment in Oropharyngeal Carcinoma: Lessons and Pitfalls for the Next Future

Background: Oropharyngeal Squamous Cell Carcinoma (OPSCC) is rapidly increasing due to the spread of Human Papillomavirus (HPV) infection. HPV-positive disease has unique characteristics, with better response to treatment and consequent better prognosis. HPV status is routinely assessed via p16 immunohistochemistry or HPV DNA Polymerase Chain Reaction. Radiomics is a quantitative approach to medical imaging which can overcome limitations due to its subjective interpretation and correlation with clinical data. The aim of this narrative review is to evaluate the impact of radiomic features on assessing HPV status in OPSCC patients. Methods: A narrative review was performed by synthesizing literature results from PUBMED. In the search strategy, Medical Subject Headings (MeSH) terms were used. Retrospective mono- or multicentric works assessing the correlation between radiomic features and HPV status prediction in OPSCC were included. Selected papers were in English and included studies on humans. The range of publication date was July 2015–April 2023. Results: Our research returned 23 published papers; the accuracy of radiomic models was evaluated by ROC curves and AUC values. MRI- and CT-based radiomic models proved of comparable efficacy. Also, metabolic imaging showed crucial importance in the determination of HPV status, albeit with lower AUC values. Conclusions: Radiomic features from conventional imaging can play a complementary role in the assessment of HPV status in OPSCC. Both primary tumor- and nodal-related features and multisequencing-based models demonstrated higher accuracy.

Endothelial cells metabolically regulate breast cancer invasion toward a microvessel.

Breast cancer metastasis is initiated by invasion of tumor cells into the collagen type I-rich stroma to reach adjacent blood vessels. Prior work has identified that metabolic plasticity is a key requirement of tumor cell invasion into collagen. However, it remains largely unclear how blood vessels affect this relationship. Here, we developed a microfluidic platform to analyze how tumor cells invade collagen in the presence and absence of a microvascular channel. We demonstrate that endothelial cells secrete pro-migratory factors that direct tumor cell invasion toward the microvessel. Analysis of tumor cell metabolism using metabolic imaging, metabolomics, and computational flux balance analysis revealed that these changes are accompanied by increased rates of glycolysis and oxygen consumption caused by broad alterations of glucose metabolism. Indeed, restricting glucose availability decreased endothelial cell-induced tumor cell invasion. Our results suggest that endothelial cells promote tumor invasion into the stroma due, in part, to reprogramming tumor cell metabolism.

Validation of early‐frame 18F‐FDG PET for CBF quantification: Comparison to simultaneous eASL measurements in memory patients

AbstractBackgroundThis study aimed to validate early [18F]‐FDG (eFDG) imaging for the quantification of cerebral blood flow (CBF), enabling dual‐marker imaging of perfusion and metabolism with a single tracer.Method19 participants with memory concerns underwent simultaneous [18F]‐FDG PET and multi delay pseudo‐continuous arterial spin labeling (eASL) MR imaging on a hybrid 3T PET/MRI scanner. eFDG‐CBF maps were generated from the first 30s, 60s, 120s and 300s after injection, and measurements were compared to ASL‐CBF using voxel‐wise cross correlation and concordance correlation for 7 regions derived from the MNI‐structural atlas.ResultHighest voxel‐wise cross‐correlation to ASL‐CBF maps were reported for 300s (5 min) eFDG (r = 0.77).Concordance correlation (CC) values were strong in all ROIs, ranging from (CC = 0.88) to (CC = 0.65) in temporal and occipital regions respectively. Mean of measurements in all ROIs were in good agreement between eFDG and ASL CBF maps, with a reported voxel‐wise mean absolute error of ±6.73 ml/100g/min between two maps.ConclusionBy simultaneous measurement of hemodynamics across modalities with a TOF‐enabled PET/MRI, we were able to demonstrate that eFDG PET is a reliable measure in mapping CBF based on strong inter‐modality correlation with ASL‐CBF, irrespective of pathophysiological variations in memory patients.

Assessing the Role of PLCG2*M28L Risk In A Novel Mouse Model Late‐Onset Alzheimer’s Disease

AbstractBackgroundMODEL‐AD has developed and characterized novel mouse models that aim to better phenocopy human LOAD for preclinical testing. More than 40 different models carrying combinations of LOAD risk factors have been created and assessed for relevance to LOAD. In this study, we aim to determine the mechanisms by which variations in the phospholipase C gamma 2 (PLCG2) gene increase risk for LOAD.MethodsThe M28L variant in PLCG2 (PLCG2*M28L) was prioritized as a LOAD risk factor. Mice were generated by CRISPR/CAS9 introduction of Plcg2*M28L variant on to LOAD1 (B6.APOE4.Trem2*R47H) and transcriptional profiling of brain hemispheres from 12 months old mice was used to evaluate molecular effects of Plcg2*M28L. To evaluate the contribution of Plcg2*M28L to LOAD risk, mice where placed on control or high fat diet (HFD) to serve as an environmental driver of neuroinflammation. Female and male LOAD1.Plcg2*M28L and LOAD1 control mice are being characterized at 4 and 12 mos through the MODEL‐AD phenotyping pipeline, which includes in vivo imaging of brain perfusion and glycolytic metabolism, multi‐omics, fluid biomarkers, cognition, and neuropathology.ResultsLOAD1.Plcg2*M28L mice showed brain transcriptomic alignment at 12 mos to human LOAD, and was prioritized for deep phenotyping. LOAD1 mice on HFD showed significant regional reductions in brain glycolysis and increased perfusion relative to controls yielding an uncoupled phenotype. By contrast, LOAD1.Plcg2*M28L mice showed a little to no regional changes in brain glycolysis or perfusion and few uncoupled regions. Multi‐resolution connectomics revealed a decrease in cluster number and organization in LOAD1 but not LOAD1.Plcg2*M28L for both sexes fed HFD compared with control diets. By 12 mos, male and female LOAD1.Plcg2*M28L mice on HFD showed opposite changes in clustering coefficient, network degree, and network density, with males showing a decrease and females an increase relative to controls. Mice carrying Plcg2*M28L variants are also being phenotyping at 18 and 24 mos.ConclusionsData collected to date reveal Plcg2*M28L on a LOAD1 background showed fewer sex‐dependent change in metabolism, perfusion and uncoupling on HFD when compared to LOAD1. These data suggest that the Plcg2*M28L risk variant on the LOAD1 background may result in an attenuated TREM2 signaling.

Celastrol ameliorates energy metabolism dysfunction of hypertensive rats by dilating vessels to improve hemodynamics.

The impact of hypertension on tissue and organ damage is mediated through its influence on the structure and function of blood vessels. This study aimed to examine the potential of celastrol, a bioactive compound derived from Tripterygium wilfordii Hook F, in mitigating hypertension-induced energy metabolism disorder and enhancing blood perfusion and vasodilation. In order to investigate this phenomenon, we conducted in vivo experiments on renovascular hypertensive rats, employing indirect calorimetry to measure energy metabolism and laser speckle contrast imaging to evaluate hemodynamics. In vitro, we assessed the vasodilatory effects of celastrol on the basilar artery and superior mesenteric artery of rats using the Multi Wires Myograph System. Furthermore, we conducted preliminary investigations to elucidate the underlying mechanism. Moreover, administration of celastrol at doses of 1 and 2mg/kg yielded a notable enhancement in blood flow ranging from 6 to 31% across different cerebral and mesenteric vessels in hypertensive rats. Furthermore, celastrol demonstrated a concentration-dependent (1 × 10-7 to 1 × 10-5M) arterial dilation, independent of endothelial function. This vasodilatory effect could potentially be attributed to the inhibition of Ca2+ channels on vascular smooth muscle cells induced by celastrol. These findings imply that celastrol has the potential to ameliorate hemodynamics through vasodilation, thereby alleviating energy metabolism dysfunctions in hypertensive rats. Consequently, celastrol may hold promise as a novel therapeutic agent for the treatment of hypertension.

A Prospective Ukrainian Multicentre Cohort Study of Pet Value Prognostic Role in Primary Patients with Hodgkin Lymphoma (HL): Six-Year a Brief Review

Introduction : The PET-adapted approach for the treatment of patients with Hodgkin's lymphoma has long been used around the world. In Ukraine, this method has recently become actively used at all stages of treatment, which allows it to meet modern standards. Airms. The primary endpoint was to assess the effectiveness of individualized approaches as a correlation between PET findings and response to therapy, type of regimen and clinical outcome (Event free (EFS) and overall survival (OS)). The second endpoint was to evaluate the impact of risk factors on the survival. Methods. Of 278 evaluable patients, 64% were female; median age 43 years (range, 17-69 years). Patients received a treatment with ABVD or ABVD/AVD (more than 50% pts); BEACOPP-14/esc or “switched-regimens” (ABVD+BEACOPP-esc/14, BEACOPP-esc/14+ABVD). Metabolic PET imaging was performed to routine protocols using Deauville criteria for response assessment. Results. Bulky disease (&amp;gt;10 cm in any dimension) were presented in 74/278 (26.6%) of pts, B symptoms - in 126/278 (45.3%) and extranodal disease had 57/278 (20.5%). 93.8% of patients achieved remission (CR/PR) during the follow-up period (median timeline: 27 months). The ORR for patients with stage I-II was 87.2% (137/157) vs 80.1% (97/121) for patients with stage III-IV. We recorded a disease progression in 44 (15.8%) patients during and after the 1st line therapy, (median time to relapse - 8 months). Only 6 pts died due to HL. In the study group, PET was performed at the beginning of treatment in 150 pts, interim in 248 and at the end of treatment in 190 pts. We found a trend in improved outcome after treatment in patients with at least two follow-up PETs (interim and EOT), indicating the effectiveness of individualized PET-adapted therapy. Interim PET-CT was assessed as DS 1-2 in 127 patients (48.4%), DS 3 in 88 (33.6%), DS 4-5 in 47 pts (17.9%). In total, the disease progression occurred in 48.3% (15/31) of interim PET-positive (PET2+) patients and 11.5% (20/174) of interim PET-negative (PET2-) patients (p&amp;lt;0.05). After 6 year of follow-up EFS decreased in patients with PET2+ by 10% than the previously reported (PET2- pts 85% and vs 44% PET2+ pts, p=0.0001). Perhaps, despite the achievement of a partial metabolic response (DS-4), patients in this group still require intensification of treatment. Intermediate-risk group cohort (2B stage) to improve the EFS levels when the regimens was given BEACOPP-esc/14+ABVD vs ABVD+BEACOPP-esc/14 vs ABVD (80% vs 60% vs 55% respectively, p=0.03) and was independent of PET2 status. Also, a more intensified treatment for patients with stage III-IV of HL showed a significantly better level of EFS compared to the ABVD regimen, and it did not depend on PET2 status (Log-rank test, p=0.0003). OS is the most patient-relevant outcome in oncology; large sample sizes and extended follow-up durations are needed to detect statistically significant differences in OS. After a median follow up of 70 months, the study met its primary endpoint in the PET-2 negative cohort, with 6-year OS of 97% versus 60% (p=0.004). Interestingly, we did not find any correlation between EFS between risk groups 2B+bulky vs 2B without bulky (p=0.9) and also 2A+ (vs) - bulky (p=0.2). But we confirmed OS higher in pts with stage 2A vs 2B (98% vs 75%, respectively, p=0.03). Conclusions . The results of the use of PET in patients with primary HL showed a high predictive value of PET, which affects event-free and overall survival.

CNS Involvement in Pediatric Hodgkin Lymphoma: A Comprehensive Retrospective Analysis from the Staging, Evaluation and Response Criteria Harmonization (SEARCH) for Childhood, Adolescent and Young Adult Hodgkin Lymphoma (CAYAHL) Group

Introduction Hodgkin lymphoma (HL) accounts for approximately 7% of childhood cancer, most frequent in adolescents and young adults. In contrast to non-Hodgkin lymphoma (NHL), central nervous system (CNS) involvement at the time of diagnosis with HL is rare and poorly understood. Information regarding the clinical presentation, management, response to treatment and outcome of patients who exhibit this finding is limited to case reports or small series. We sought to describe CNS involvement at the time of diagnosis with pediatric HL by performing a retrospective analysis of 3 large international clinical trials. Methods Patients with CNS involvement were identified from the imaging databases of the COG trial AHOD1331 (NCT02166463) and EuroNet trials PHL-C1 (NCT00433459, EudraCT 2006-000995-33) and PHL-C2 (NCT02684708, EudraCT 2012-004053-88). Imaging was reviewed collaboratively by COG and Euronet radiologists and nuclear medicine physicians with expertise in HL, with input from radiation oncologists and pediatric oncologists. All identified cases of CNS involvement had morphologic (CT) and metabolic (FDG-PET) imaging prior to initiation of therapy, as well as disease response assessment after 2 cycles of therapy. Variables evaluated included: age, sex, Ann Arbor stage, histology, symptoms at the time of presentation (pain, neurologic symptoms), corticosteroid administration prior to FDG-PET scan, number and location of CNS lesions, tissue of origin of the CNS lesion, anatomic description of the involvement of the CNS lesion, number and location of E-lesions, whether emergency irradiation or an operative procedure were performed at diagnosis, FDG tracer uptake at the time of initial staging, response of the CNS lesions after 2 cycles of chemotherapy, whether relapse occurred and in which location. CNS involvement was defined in 2 ways: (1) lesions originating within the CNS parenchyma and (2) lesions extending into the CNS. Results 45 patients with 55 CNS lesions were identified from a combined cohort of 5569 patients with a new diagnosis of HL. 9 patients presented with pain and 4 with neurologic symptoms, however information regarding clinical symptoms was not available for 34/45 patients. Symptoms corresponded to the location of the CNS lesion. All identified lesions extended into the CNS from surrounding tissue, none originated within the CNS parenchyma. 82.2% of patients had a single lesion extending into the CNS, most commonly through the neural foramina into the thoracic spine (45.5%), sacrum (23.6%) or lumbar spine (21.8%). Lesions originated from adjacent bone (45%) or soft tissue (40%). 89% of patients with CNS lesions had stage IV HL, and 68.8% had extranodal (non-CNS) disease. 54.8% of lesions displaced the spinal cord, but none infiltrated the spinal cord itself. After 2 cycles of chemotherapy, 67.3% of CNS lesions had a &amp;gt;75% reduction in size or complete resolution, and 32.7% of CNS lesions decreased in volume by 50-75%. A residual mass was present for 74% of lesions involving the neural foramina after 2 cycles of chemotherapy. 89.1% of lesions were PET negative at interim response assessment (IRA). 2 CNS lesions were associated with relapse at the CNS site, these were PET negative at IRA. 13 lesions received irradiation, none of these were sites of subsequent relapse. Conclusions This large, combined cohort of intermediate- and high-risk pediatric patients enrolled on clinical trials from 2007 to 2021 confirms the rarity of CNS involvement at the time of diagnosis with HL, with an overall incidence of 0.8%. Importantly, CNS lesions extended from adjacent tissue and did not originate within the CNS itself. These lesions never directly infiltrated the brain parenchyma or spinal cord. They were highly metabolically active at diagnosis, and demonstrated an excellent metabolic and morphologic response to the first 2 cycles of chemotherapy. Patients with CNS involvement had a 2-fold greater incidence of extranodal disease than previously reported cohorts. In summary, this retrospective study provides key information about CNS involvement in pediatric HL at the time of diagnosis, contributing to our understanding of this rare, yet important, clinical presentation.

Low Tmtv Influences Response and Outcomes in R/R DLBCL 3L+ Patients Treated with CAR-T Cells : First Results of FDG-PET/CT Analysis in the French Descar-T Registry

Context : DESCAR-T is a French national registry designed by LYSA/LYSARC including real-life patients receiving commercial CAR T-cells for hematologic malignancies. We initiated a project to conduct a centralized review of Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography (FDG-PET/CT) performed before CAR T-cells infusion, and during follow-up, to evaluate the impact of several metabolic imaging parameters at baseline and response assessment. Materials and methods : Patients with relapsed/refractory (R/R) DLBCL who initiated at least a third line of therapy (3L+) from the DESCAR-T registry and treated with commercial anti-CD19 CAR T-cells, with at least one central reviewed PET before CAR T-cell infusion (PRE-CAR T), at one month (M1) or three months (M3) after infusion, were included. For each visit, Total Metabolic Tumor Volume (TMTV) and SUVmax of the tumor were measured. Deauville score (DS) and response according to 2014 Lugano classification were registered on follow-up FDG-PET/CT. TMTV optimal cut-off for survival prediction (PFS and OS) was determined using X-tile analysis and association of DS with prognosis was studied. Progression-free survival (PFS) was defined as the time between CAR T-cell infusion and progression during follow-up. Overall survival (OS) was defined as the time between CAR T-cell treatment and death during follow-up. Results : Our analysis included FDG-PET/CT data from 212 R/R DLBCL patients (59 treated with tisagenlecleucel and 153 with axicabtagene ciloleucel). Median follow-up was 24.1 months and overall response rate was 47.1% with 112 patients presenting progression or relapse. On PRECAR-T FDG-PET/CT, the median SUVmax was 16.1 (25th-75th percentiles, 8.55-25.30) and median TMTV was 43.91 cm3 (25th-75th percentiles, 12.79-140.43 cm3). Tumor burden significantly affected survival using a TMTV optimal cut-off of 30 cm3. It was associated with a shorter PFS in patients with PRECAR-T TMTV ≥30 cm3 compared with &amp;lt;30 cm3 (median of 3 vs 22.2 months; p=0.0001; respectively) and a shorter OS (median of 9.4 vs 32 months ; p=0.0001; respectively). Regarding metabolic response at M1, reported in 192 patients, DS 1-3 (n=120; 62.5%) was significantly associated with better PFS and OS than DS4-5 (n=72; 37.5%) (for PFS: median of 1.3 vs 21.8 months ; p&amp;lt;0.0001; for OS: median of 4.5 vs 30.6 months; p&amp;lt;0.0001). Of note, considering only DS5 (n=46; 24%) as unequivocally insufficient response onM1 evaluation, identified patients with the poorest outcomes (for PFS: median of 0 month vs 21.2 months ; p&amp;lt;0.0001; for OS: median of 4.5 months vs 31.1 months; p&amp;lt;0.0001). Conclusion : Low PRECAR-T TMTV influences response and retains its predictive and prognostic value in R/R DLBCL patients treated with anti-CD19 CAR T-cells. Moreover, metabolic response assessed with DS is significantly associated with patients' outcome.

Application and development of Deuterium Metabolic Imaging in tumor glucose metabolism: visualization of different metabolic pathways

Cancer metabolism has emerged as a pivotal area of research recently. The ability to visualize and comprehend the metabolic processes of cancer holds immense clinical value, particularly in the diagnosis of malignant tumors and the assessment of treatment responses. Deuterium Metabolic Imaging (DMI), as a robust, simple, and versatile MR spectroscopic imaging tool, demonstrates promise in tumor diagnosis and treatment efficacy assessment. This review explored the latest developments and applications of DMI in oncology across various tumor metabolic axes, with a specific emphasis on its potential for clinical translation. DMI offers invaluable insights into tumor biology, treatment responses, and prognostic outcomes. Notably, DMI can identify early responses to immunotherapy, a prominent area of current research interest. In conclusion, DMI harbors the potential to evolve into a convenient and efficient imaging technique in clinical practice, thereby advancing precision medicine and improving the diagnosis and evaluation of cancer treatments.

Imaging tumor lactate is feasible for identifying intermediate-risk prostate cancer patients with postsurgical biochemical recurrence.

While radical prostatectomy remains the mainstay of prostate cancer (PCa) treatment, 20 to 40% of patients develop postsurgical biochemical recurrence (BCR). A particularly challenging clinical cohort includes patients with intermediate-risk disease whose risk stratification would benefit from advanced approaches that complement standard-of-care diagnostic tools. Here, we show that imaging tumor lactate using hyperpolarized 13C MRI and spatial metabolomics identifies BCR-positive patients in two prospective intermediate-risk surgical cohorts. Supported by spatially resolved tissue analysis of established glycolytic biomarkers, this study provides the rationale for multicenter trials of tumor metabolic imaging as an auxiliary tool to support PCa treatment decision-making.

Salvage Radical Prostatectomy for Recurrent Prostate Cancer: A Systematic Review (French ccAFU).

The aim of this study was to systematically review the current evidence regarding the oncological and functional outcomes of salvage radical prostatectomy (sRP) for recurrent prostate cancer. A systematic review was conducted throughout September 2022 using the PubMed, Science Direct, Scopus, and Embase databases. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed to identify eligible studies. A total of 55 studies (3836 patients) met our eligibility criteria. The vast majority of men included had radiation therapy (including brachytherapy) as their first-line treatment (n = 3240, 84%). Other first-line treatments included HIFU (n = 338, 9%), electroporation (n = 59, 2%), proton beam therapy (n = 54, 1.5%), cryotherapy (n = 34, 1%), focal vascular targeted photodynamic therapy (n = 22, 0.6%), and transurethral ultrasound ablation (n = 19, 0.5%). Median preoperative PSA, at the time of recurrence, ranged from 1.5 to 14.4 ng/mL. The surgical approach was open in 2300 (60%) cases, robotic in 1465 (38%) cases, and laparoscopic in 71 (2%) cases. Since 2019, there has been a clear increase in robotic versus conventional surgery (1245 versus 525 cases, respectively). The median operative time and blood loss ranged from 80 to 297 min and 75 to 914 mL, respectively. Concomitant lymph node dissection was performed in 2587 cases (79%). The overall complication rate was 34%, with a majority of Clavien grade I or II complications. Clavien ≥ 3 complications ranged from 0 to 64%. Positive surgical margins were noted in 792 cases (32%). The median follow-up ranged from 4.6 to 94 months. Biochemical recurrence after sRP ranged from 8% to 51.5% at 12 months, from 0% to 66% at 22 months, and from 48% to 59% at 60 months. The specific and overall survival rates ranged from 13.4 to 98% and 62 to 100% at 5 years, respectively. Urinary continence was maintained in 52.1% of cases. sRP demonstrated acceptable oncological outcomes. These results, after sRP, are influenced by several factors, and above all by pre-treatment assessment, including imaging, with the development of mpMRI and metabolic imaging. Our results demonstrated that SRP can be considered a suitable treatment option for selected patients, but the level of evidence remains low.

Short-term consumption of highly processed diets varying in macronutrient content impair the sense of smell and brain metabolism in mice

ObjectiveFood processing greatly contributed to increased food safety, diversity, and accessibility. However, the prevalence of highly palatable and highly processed food in our modern diet has exacerbated obesity rates and contributed to a global health crisis. While accumulating evidence suggests that chronic consumption of such foods is detrimental to sensory and neural physiology, it is unclear whether its short-term intake has adverse effects. Here, we assessed how short-term consumption (<2 months) of three diets varying in composition and macronutrient content influence olfaction and brain metabolism in mice. MethodsThe diets tested included a grain-based standard chow diet (CHOW; 54% carbohydrate, 32% protein, 14% fat; #8604 Teklad Rodent diet , Envigo Inc.), a highly processed control diet (hpCTR; 70% carbohydrate, 20% protein, 10% fat; #D12450B, Research Diets Inc.), and a highly processed high-fat diet (hpHFD; 20% carbohydrate, 20% protein, 60% fat; #D12492, Research Diets Inc.). We performed behavioral and metabolic phenotyping, electro-olfactogram (EOG) recordings, brain glucose metabolism imaging, and mitochondrial respirometry in different brain regions. We also performed RNA-sequencing (RNA-seq) in the nose and across several brain regions, and conducted differential expression analysis, gene ontology, and network analysis. ResultsWe show that short-term consumption of the two highly processed diets, but not the grain-based diet, regardless of macronutrient content, adversely affects odor-guided behaviors, physiological responses to odorants, transcriptional profiles in the olfactory mucosa and brain regions, and brain glucose metabolism and mitochondrial respiration. ConclusionsEven short periods of highly processed food consumption are sufficient to cause early olfactory and brain abnormalities, which has the potential to alter food choices and influence the risk of developing metabolic disease.

High-sensitivity deuterium metabolic MRI differentiates acute pancreatitis from pancreatic cancers in murine models

Deuterium metabolic imaging (DMI) is a promising tool for investigating a tumor’s biology, and eventually contribute in cancer diagnosis and prognosis. In DMI, [6,6′-2H2]-glucose is taken up and metabolized by different tissues, resulting in the formation of HDO but also in an enhanced formation of [3,3′-2H2]-lactate at the tumor site as a result of the Warburg effect. Recent studies have shown DMI’s suitability to highlight pancreatic cancer in murine models by [3,3′-2H2]-lactate formation; an important question is whether DMI can also differentiate between these tumors and pancreatitis. This differentiation is critical, as these two diseases are hard to distinguish today radiologically, but have very different prognoses requiring distinctive treatments. Recent studies have shown the limitations that hyperpolarized MRI faces when trying to distinguish these pancreatic diseases by monitoring the [1-13C1]-pyruvate→[1-13C1]-lactate conversion. In this work, we explore DMI’s capability to achieve such differentiation. Initial tests used a multi-echo (ME) SSFP sequence, to identify any metabolic differences between tumor and acute pancreatitis models that had been previously elicited very similar [1-13C1]-pyruvate→[1-13C1]-lactate conversion rates. Although ME-SSFP provides approximately 5 times greater signal-to-noise ratio (SNR) than the standard chemical shift imaging (CSI) experiment used in DMI, no lactate signal was observed in the pancreatitis model. To enhance lactate sensitivity further, we developed a new, weighted-average, CSI-SSFP approach for DMI. Weighted-average CSI-SSFP improved DMI’s SNR by another factor of 4 over ME-SSFP—a sensitivity enhancement that sufficed to evidence natural abundance 2H fat in abdominal images, something that had escaped the previous approaches even at ultrahigh (15.2 T) MRI fields. Despite these efforts to enhance DMI’s sensitivity, no lactate signal could be detected in acute pancreatitis models (n = 10; [3,3′-2H2]-lactate limit of detection < 100 µM; 15.2 T). This leads to the conclusion that pancreatic tumors and acute pancreatitis may be clearly distinguished by DMI, based on their different abilities to generate deuterated lactate.

Autofluorescence imaging of endogenous metabolic cofactors in response to cytokine stimulation of classically activated macrophages.

Macrophages are one of the most prevalent subsets of immune cells within the tumor microenvironment and perform a range of functions depending on the cytokines and chemokines released by surrounding cells and tissues. Recent research has revealed that macrophages can exhibit a spectrum of phenotypes, making them highly plastic due to their ability to alter their physiology in response to environmental cues. Recent advances in examining heterogeneous macrophage populations include optical metabolic imaging, such as fluorescence lifetime imaging (FLIM), and multiphoton microscopy. However, the method of detection for these systems is reliant upon the coenzymes NAD(P)H and FAD, which can be affected by factors other than cytoplasmic metabolic changes. In this study, we seek to validate these optical measures of metabolism by comparing optical results to more standard methods of evaluating cellular metabolism, such as extracellular flux assays and the presence of metabolic intermediates. Here, we used autofluorescence imaging of endogenous metabolic co-factors via multiphoton microscopy and FLIM in conjunction with oxygen consumption rate and extracellular acidification rate through Seahorse extracellular flux assays to detect changes in cellular metabolism in quiescent and classically activated macrophages in response to cytokine stimulation. Based on our Seahorse XFP flux analysis, M0 and M1 macrophages exhibit comparable trends in oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). Autofluorescence imaging of M0 and M1 macrophages was not only able to show acute changes in the optical redox ratio from pre-differentiation (0 hours) to 72 hours post-cytokine differentiation (M0: 0.320 to 0.258 and M1: 0.316 to 0.386), mean NADH lifetime (M0: 1.272 ns to 1.379 ns and M1: 1.265 ns to 1.206 ns), and A1/A2 ratio (M0: 3.452 to ~ 4 and M1: 3.537 to 4.529) but could also detect heterogeneity within each macrophage population. Overall, the findings of this study suggest that autofluorescence metabolic imaging could be a reliable technique for longitudinal tracking of immune cell metabolism during activation post-cytokine stimulation.

NIMG-22. COMPARISON OF NON-INVASIVE, ML-GENERATED WHOLE-BRAIN SPATIAL RADIOPATHOMIC MAPS DERIVED FROM ANATOMICAL AND DIFFUSION-WEIGHTED MRI ON PATIENTS WITH NEWLY DIAGNOSED-GLIOMA

Abstract INTRODUCTION Spatial heterogeneity in the glioma microenvironment is difficult to capture through singular biopsy samples. Identification of malignant tumor regions can help guide diagnosis and treatment planning. This study compares radiopathomic maps from 2 strategies derived from anatomical and diffusion-weighted MRI: 1) a support vector machine model trained on an MRI dataset with tissue samples of known spatial coordinates to generate spatial maps of probability of KI-67 and cellularity, and 2) a bagged random-forest model derived from 40+ person glioma brain bank of autopsy tissue coregistered to end-of-life MRI to generate spatial maps of cellularity and tumor probability (TPM). We hypothesize that TPMs from autopsy samples will correlate with KI-67 predictions, while cellularity values among methods will correlate. METHODS Spatial maps of tumor pathology from autopsy- and tissue sample-based models were generated on 55 patients newly-diagnosed with glioblastoma that were scanned with anatomical, diffusion-weighted, and metabolic imaging. Mean values were extracted from each map within the T2-hyperintense, non-enhancing lesion (NEL), the contrast-enhancing lesion (CEL), normal-appearing white matter (NAWM), and 5mm diameter spheres centered at the location where tissues were taken. Spearman correlation analysis was used to elucidate the strength of the linear relationship within the selected regions between the two maps. RESULTS Correlations between KI-67 and TPM values were highest and most significant at the tissue sample locations and CEL (ρ=0.306, p=0.002 and ρ=0.312, p=0.044 respectively). Cellularity maps generated from the autopsy-based model showed no significant correlation with newly diagnosed cellularity values at tissue sample locations, potentially highlighting the influence of treatment. CONCLUSION This study examines the current state of ML-generated spatial mapping, highlighting similarities within CEL, but need to account for the effects of subsequent treatment and progression when comparing tumor beyond the CEL between models derived between different time points.