RPS 2211 - Contrast agents and energy sustainability in neuroimaging

Author Block: C. Deuschl¹, K. Kudo², A. Liu³, M. A. Klemens³, B. M. Hofmann³, P. Palkowitsch³, B. P. Liu⁴; ¹Essen/DE, ²Sapporo/JP, ³Berlin/DE, ⁴Chicago, IL/US
Purpose: This dose-finding Phase 2 study for the novel tetrameric macrocyclic GBCA gadoquatrane investigated the efficacy of 0.04 mmol Gd/kg body weight (bw) gadoquatrane in comparison to 0.1 mmol Gd/kg bw gadobutrol for CE-MRI in patients with CNS lesions at 5-, 10- and 15-min post injection (pi).
Methods or Background: Adult patients with CNS lesions were included in the study and underwent two CE-MRIs within an interval of 3 to 14 days, first gadobutrol, then gadoquatrane. Images were acquired at 5- (3D IR-GRE), 10- (2D-SE) and 15-min pi (3D IR-GRE). The 5-, 10- and 15-min CE-MRIs were assessed in the Blinded Independent Central Review using visualization parameters (contrast enhancement, border delineation, internal morphology) to investigate the time course of enhancement. Quantitative signal intensity measurements were also performed. Safety parameters were assessed and pharmacokinetic (PK) samples were taken to determine plasma concentrations for both GBCAs.
Results or Findings: The sum of the lesion visualization parameters at each point for the average reader was very similar for gabobutrol (9; 8.86; 9.09) and gadoquatrane (8.94; 8.8; 8.97), with differences close to zero (-0.06; -0.06; -0.12). These results were representative for the three individual readers and each visualization parameter. The results of the quantitative measurements supported the qualitative evaluations. The safety and concentration-time profile of gadoquatrane were very similar to gadobutrol, but dose-proportionally lower.
Conclusion: Gadoquatrane at a dose of 0.04 mmol Gd/kg bw shows similar efficacy as gadobutrol at 0.1 mmol Gd/kg bw on 5-, 10- and 15-min pi CE-MRI images.
Limitations: The limitation of the study is the small sample size of 50 evaluable patients.
Funding for this study: This Phase 2 study was sponsored by Bayer AG.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethics vote from all sites available.

Author Block: J. Vymazal, Z. Ryznarova, R. Liščák, A. Rulseh; Prague/CZ
Purpose: To demonstrate the role of gadopiclenol in MR imaging of brain metastases with at standard (0.05 mmol/kg) and double dose (0.1 mmol/kg), including delayed examination (ca 15 minutes after contrast administration).
Methods or Background: Ninety-one subjects with known brain metastases underwent MRI prior to radiosurgery (44 female, mean age 64.2 ±12 years). A standard T1W 3D SPACE sequence was acquired in all subjects (3 subjects at 1.5T, 88 at 3T) post-contrast, followed by a delayed acquisition. In roughly half of subjects (n=47), the delayed acquisition was preceded by additional contrast administration (cumulative double dose). After randomization, 3 blinded readers evaluated the number of lesions for each patient in 2 sessions, 1 month apart. A paired t-test was used to compare early and late evaluations in the two groups (subjects with cumulative single dose or double dose), the Welch t-test was used to compare differences in (late-early) single versus (late-early) double doses.
Results or Findings: Agreement between all three blinded readers was used for evaluation. The late single dose exam revealed 170 metastatic lesions compared to 161 metastatic lesions on the early exam. Late double-dose exam revealed 138 metastatic lesions compared to 121 metastatic lesions on the single dose early exam. The number of lesions on early versus late (single/double dose) exams did not differ significantly (p=0.4 and p=0.11, respectively). No significant difference was detected between double dose and delayed single dose.
Conclusion: Although relatively more lesions were detected on delayed exam (single/double dose), the difference did not reach significance, likely reflecting small effect size. Furthermore, no significant difference was found between late single and double dose.
Limitations: The study was performed at a single institution. Only the SPACE sequence was used for blinded reading.
Funding for this study: Supported by MH CZ - DRO (NNH, 00023884) No. 244302
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Approved on June, 5, 2024

Author Block: M. Rasschaert, E. Couloumy, C. Hollenbeck, E. Renard, I. Janot, N. Decout, M. Lefebvre, C. Factor, P. Robert; Roissy CdG Cedex/FR
Purpose: Gadopiclenol is a high relaxivity macrocyclic Gadolinium-Based Contrast Agent (mGBCA) approved in 2022 in the USA and December 2023 in Europe. The aim of this study was to evaluate the time-dependent gadolinium Gd exposure in main body organs over 5 months in rats after a single injection of gadopiclenol or two mGBCAs.
Methods or Background: Healthy female rats were allocated to 3 groups: gadopiclenol (Elucirem®), gadobutrol (Gadovist®) and gadoterate (Dotarem®). One single administration of GBCA at the Human Equivalent Dose was realized, blinded. Selected tissues (including central (CNS) and peripheric nervous system (PNS) organs, excretion organs, bone) were collected for total Gd determination by Inductive Coupled Plasma-Mass Spectrometry at 1 day, 1 week, 1 or 5 months after injection (n=10/group and timepoint). The global exposure to Gd in all investigated organs was estimated by calculating the area under the curve (AUC).
Results or Findings: After gadopiclenol administration, the Gd exposure over the 5 months compared to gadoterate and gadobutrol was respectively -43% and -41% in CNS, -28% and -32% in PNS (sciatic nerve, spinal nodes, footpads, spinal cord), -25% and -68% in skin, -1% and -26% in liver, -19% to -44% in kidney and -31% to -39% in spleen. In bone, the Gd exposure after gadopiclenol administration was +80% and +16% higher in femur diaphysis, -1% and +48% in epiphysis. In bone marrow, the AUC was -22% and -35% lower compared to gadobutrol and gadoterate respectively. Globally, the overall Gd exposition was -25% and -40% after gadopiclenol compared to gadoterate and gadobutrol, respectively.
Conclusion: In our experimental conditions, the measured exposure to Gd after gadopiclenol injection is significantly reduced compared to the other marketed GBCAs in most of the investigated organs.
Limitations: Animal Study
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Research project 2015080615264829 approved by French MESR Ministry

Author Block: S. M. Sceppacuercia¹, C. Tur¹, A. H. M. E. Hammam², W. H. E. Hamed², O. Sarwani², D. Deborah¹, C. Auger Acosta¹, T. A. Yousry², A. Rovira Cañellas¹; ¹Barcelona/ES, ²London/UK
Purpose: To describe the evolution of GBCA use, the detection of Gd-enhancing, and new T2 lesions over time in two independent cohorts of MS patients. We also examined the association between new T2 lesions and clinical features, focusing on the role of GBCA use.
Methods or Background: We included all MS patients clinical MRIs at the Multiple Sclerosis Centre of Catalonia, Spain, and the Queen Square MS Centre, UK, during May from 2015 to 2022. Clinical and demographic data included age, sex, disease duration, clinical phenotype, progression, relapses since the last MRI, and DMT variables. Brain MRI data included GBCA use, the number of Gd+ lesions, and new T2 lesions. Statistical analysis used logistic regression models adjusted for confounders.
Results or Findings: 479 patients(cohort1), and 794 (cohort2). Both cohorts showed a significant decrease in GBCA use over time, an increase in DMT exposure (p=0.032), and a reduction in relapses (p<0.001) and progression events (p=0.006). A significant reduction in Gd-enhancing lesions was observed in Barcelona. The detection of new lesions also decreased over time, likely due to an older population (p<0.001) and increased use of high-efficacy DMTs (p<0.001). GBCA administration was independently associated with a higher likelihood of detecting new lesions (p=0.030).
Conclusion: Over time, there was a decrease in GBCA use, Gd-enhancing lesion detection, and new/enlarging T2 lesions, suggesting a trend towards a less aggressive disease course, possibly due to more effective DMTs and an aging population. GBCA use was independently associated with higher detection of new T2 lesions, possibly reflecting heightened neuroradiologist vigilance when new inflammatory activity is suspected and the facilitation of T2 lesion detection by Gd-enhancing lesions.
Limitations: This includes the retrospective nature, a single month/year representation and unequal MRIs' frequencies among years and centres.
Funding for this study: A retrospective study with no fund needed.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: A retrospective study.

Author Block: I. Shahid, E. Lancelot; Paris/FR
Purpose: Some patients who received multiple administrations of gadolinium-based contrast agents (GBCAs) have been reported to develop “symptoms associated with gadolinium exposure” (SAGE).
The aim of this study was to analyze pharmacovigilance data and to explore the various SAGE patterns of linear and macrocyclic GBCAs among patients exhibiting three or more SAGE symptoms.
Methods or Background: SAGE symptoms were searched by preferred terms (PTs) in different system organ class (SOC) categories in the FDA Adverse Event Reporting System (FAERS) database, over a 6-year period ranging from 2014 to 2019, for 3 linear and 3 macrocyclic GBCAs.
Results or Findings: The analysis of FAERS data revealed a significantly higher SAGE weight for the linear GBCAs (20-24%) than for the macrocyclic GBCAs (5-9%). For the linear GBCAs, the most prevalent combinations of 3 SAGE symptoms were reported in 152-164 occurrences, while for the macrocyclic GBCAs this range was significantly lower (1-13 occurrences). Moreover, the patterns of SAGE combinations differed significantly between both categories of GBCAs.
Conclusion: Linear GBCAs are associated with higher SAGE reporting rates than macrocyclic GBCAs. They also present different patterns of SAGE combinations.
Limitations: This study did not provide any demonstration of a causal relationship between the reported events and GBCA administration to the patients.
Funding for this study: None
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not Applicable (No patients were involved)

Author Block: S. Kalari¹, I. Seimenis¹, E. Psatha², D. Apostolou¹, I. Loulakas¹, E. Karavasilis²; ¹Athens/GR, ²Alexandroupolis/GR
Purpose: Compressed-sensing is a new acquisition technique that enables efficient signal acquisition and reconstruction reducing the scanning time. The aim of our study was to estimate the impact of CS on energy consumption during brain imaging.
Methods or Background: Thirty individuals underwent brain MRI using the same exam protocol including 3DT1, 3DT2 and 3DΤ2 Flair with and without CS on a 3.0TPhilips MRI system. Energy consumption was recorded using kilowatt-hour energy measurement sensors (0.017 Hz sampling rate) for all the above sequences. The 3DT1, 3DT2 and 3DT2 Flair with and without CS image quality was assessed quantitatively using VolBrain free available online software. Images were also reviewed from an experienced neuroradiologist who evaluated their total image quality and 3DT2 Flair lesion detection sensitivity. Sequences’ signal to noise ratio (SNR), image quality indices derived from VolBrain, qualitative indices and their energy consumption were introduced to SPSS to perform paired t-test statistical analysis (p<0.05).
Results or Findings: The mean acquisition time of 3DT2 FLAIR, 3DT2 and 3DT1 with and without CS were 210sec±0.8sec vs 390sec±1.1sec, 200sec±0.7sec vs 370sec±1sec and 230sec±0.1sec vs 400sec±1.2sec respectively. We didn’t find any statistical differences in both image qualitative and quantitative quality metrics. There was no substantial difference of the SNR. Concerning the energy consumption/min CS increased by 42% the energy consumption rate in 3DT2 FLAIR (0.57kWh/min versus 0.40kWh/min) therefore the total energy consumption was decreased by 10% (1,99 versus 2.2 kWh). 3DT2 and 3DT1 energy with and without CS consumption rate were 0.60kWh/min, 0.56kWh/min and 0.58kwh/min and 0.53kwh/min. Thus, the 3DT2 and 3DT1 total energy consumption were decreased 45,9% and 42,5%, respectively.
Conclusion: CS image acceleration technique has the potential to reduce MRI scanning time and energy required while maintaining high image quality.
Limitations: Not applicable
Funding for this study: No funding was provided for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study received institutional review board approval and written consent was obtained from all participants.

Author Block: A. Roletto¹, M. Verga², G. L. Viganò², S. Zanoni²; ¹Milan/IT, ²Brescia/IT
Purpose: Magnetic resonance imaging (MRI) scanners contribute significantly to the carbon footprint of healthcare sector, and efforts to reduce environmental impact are based on reducing energy consumption. The aim of this work was to develop a methodology to reduce carbon emissions by reorganising an MRI neuroradiology system's diagnostic activities based on daily electricity emission data.
Methods or Background: In July 2024, at a large public hospital of Brescia (Italy), the energy profiles of two weeks of diagnostic activity of a neuroradiology MRI system were recorded using HT GSC60 Power Meter/Analyzer (HT-Italia, Italy), calculating the total energy consumption and its distribution over days. Finally, the amount of carbon dioxide equivalent (CO2e) emitted by electricity consumption was calculated using open-source daily emission data (www.electricitymaps.com) and the amount that can be saved by rescheduling diagnostic activities to lower emission day periods.
Results or Findings: The total weekly energy consumption was 2305.1 kWh, spread over 5 working days, from 7am to 7pm. The most performed examinations were brain MRI (25 kWh/scan) and lumbar spine MRI (18 kWh/scan). Total emissions were 373.5 kgCO2e, equivalent to emissions from one homes' energy use for six months. Examinations performed between 4pm and 7pm have the highest carbon emission index (213.4-252.3 gCO₂eq/kWh). Rescheduling them earlier in the working day or at the weekend would reduce emissions by 18%, without any decrease of energy consumed.
Conclusion: This study shows how clinicians and managers can reduce carbon emissions from MRI diagnostic activity, not only by reducing energy consumption through cutting unnecessary examinations or optimising the acquisition technique, but also by rescheduling work activities according to daily electricity emission data, scheduling examinations during low-carbon emission times.
Limitations: Short period of data collection limited the strength of the conclusions of this study.
Funding for this study: Not applicable
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not applicable