Investigative Radiology最新文献

{"title":"Pharmacokinetics, Safety, and Dialyzability of Gadoquatrane in Patients With Impaired Renal Function: A Comprehensive Investigation Using Clinical Trial Data, Modeling and Simulation, and In Vitro Data.","authors":"Tommaso Fadini, Gabriele Sutter, Stefan Klein, Eva Busemann, Esmée Vendel, Peter Vis, Stefan Heitmeier, Thomas Frenzel, Wolfgang Ebert, Birte Maria Hofmann","doi":"10.1097/RLI.0000000000001191","DOIUrl":"10.1097/RLI.0000000000001191","url":null,"abstract":"<p><strong>Objectives: </strong>The aims of the study were to evaluate the safety, tolerability and pharmacokinetics of gadoquatrane in men and women with mild to moderate renal impairment and in matching participants with normal renal function, to predict the pharmacokinetics of gadoquatrane in patients with severe renal impairment, and to assess the dialyzability of gadoquatrane. Gadoquatrane is a new gadolinium-based contrast agent (GBCA) currently in clinical development.</p><p><strong>Materials and methods: </strong>This evaluation used data from an open-label, nonrandomized, single-dose study in the following 3 parallel cohorts: (i) participants with mild renal impairment, (ii) participants with moderate renal impairment, and (iii) matching controls with normal renal function (3 × 8 = 24 participants between 51 and 79 years of age; 14 women). Each participant received a single IV bolus injection of gadoquatrane (0.025 mmol/kg body weight, corresponding to 0.1 mmol Gd/kg). Study procedures included safety assessments and collection of plasma and urine samples over 6 months. Gadolinium concentrations in plasma and urine were determined by inductively coupled plasma mass spectrometry. Modeling and simulation were used to predict the exposure in patients with severe renal impairment. In vitro experiments were used to assess the dialyzability of gadoquatrane.</p><p><strong>Results: </strong>Following IV injection, gadolinium plasma concentrations rapidly declined in all cohorts, albeit at different rates depending on renal function. With increasing degree of renal impairment, the exposure increased and the total as well as the renal clearance decreased. The total body weight-normalized clearance was lower by 21% in participants with mild renal impairment (90% confidence interval: 4; 35%) and by 42% in participants with moderate renal impairment (90% confidence interval: 30; 53%) than in participants with normal renal function. Maximum plasma concentration and volume of distribution were similar in all cohorts. The mean effective plasma half-life, which reflects the overall elimination of gadoquatrane, was short, even in participants with moderate renal impairment (4.1 hours; coefficient of variation: 31.2%). In all cohorts, approximately 90% of the injected dose was recovered in urine within the first 24 hours; after 7 days, recovery was practically complete (92%-97% of the dose administered, on average). Only trace amounts of gadolinium continued to be excreted (median recovery in 24-hour urine in all cohorts at 6 months after the injection: <0.0001% of the dose administered). For patients with severe renal impairment, simulations indicated a continuous decrease in gadoquatrane clearance and increase in exposure with increasing severity of renal impairment. Dialyzability experiments showed that the in vitro kinetic dialysis profile of gadoquatrane is essentially the same as that of gadobutrol.</p><p><strong>Conclusions: </strong>Gadoquatrane sh","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"779-790"},"PeriodicalIF":8.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12490336/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143971617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Vitro and In Vivo Stability Assessment of the Novel, Macrocyclic Gadolinium-Based Contrast Agent Gadoquatrane.","authors":"Stephan Gruendemann, Thomas Frenzel, Jessica Lohrke, Janina Boyken, Gregor Jost, Markus Berger, Hannes-Friedrich Ulbrich, Hubertus Pietsch","doi":"10.1097/RLI.0000000000001195","DOIUrl":"10.1097/RLI.0000000000001195","url":null,"abstract":"<p><strong>Objectives: </strong>Gadoquatrane is a tetrameric extracellular gadolinium-based contrast agent (GBCA) with a T1 relaxivity of 11.8 L/(mmol Gd*s) at 1.41 T in human plasma, which is currently in Phase 3 clinical development. In the current study, the stability of gadoquatrane was assessed in comparison with approved macrocyclic GBCAs in several in vitro and in vivo assays.</p><p><strong>Materials and methods: </strong>Kinetic inertness, a key determinant of complex stability, was assessed for gadoquatrane, gadoteridol, gadobutrol, gadoterate, and gadopiclenol at equimolar Gd concentrations by measuring the time course of dissociation at pH 1.2 and 37°C using a complexometric assay. Kinetic inertness was also determined in human plasma at pH 7.4 and 37°C using ion exchange chromatography coupled to inductively coupled plasma mass spectrometry (ICP-MS). The binding of gadoquatrane, gadobutrol, and gadopiclenol to synthetic hydroxyapatite, the inorganic component of bone, was investigated in vitro and the Gd content in histological bone slices 1 week after a single injection of these 3 selected GBCAs in rats (0.6 mmol Gd/kg, equivalent to a human dose of 0.1 mmol Gd/kg) was analyzed using laser ablation coupled to ICP-MS.</p><p><strong>Results: </strong>The dissociation half-lives at pH 1.2 (mean, 95% confidence interval in parenthesis) were 28.6 (28.1, 29.1) days for gadoquatrane, 14.2 (13.8, 14.6) days for gadopiclenol, 2.7 (2.6, 2.8) days for gadoterate, 14.1 (13.1, 15.1) hours for gadobutrol, and 2.2 (2.0, 2.4) hours for gadoteridol. After 15 days of incubation in human plasma at pH 7.4, no released Gd 3+ ions above the lower limit of quantification (LLOQ, 0.01% of total Gd) were observed for gadoquatrane and gadoterate, while for gadobutrol, gadopiclenol and gadoteridol the concentrations of released Gd 3+ ions reached 0.12 (0.11, 0.13)%, 0.20 (0.19, 0.21)%, and 0.20 (0.20, 0.21)%, respectively. The rates of dissociation for gadopiclenol and gadoteridol were similar. For gadoquatrane, gadobutrol, and gadopiclenol, the binding to hydroxyapatite was examined. It was very low (< 0.02% of total Gd) for all 3 GBCAs. The Gd concentration 1 week after the injection of 0.6 mmol Gd/kg of the 3 GBCAs in bone marrow were in a comparable range of 2.3-3.0 nmol Gd/g tissue. In the epiphysis the Gd concentrations for gadoquatrane (1.2 (1.0, 1.4)) and gadobutrol (1.2 (1.0, 1.4)) were lower compared to gadopiclenol (2.2 (1.9, 2.6)). In the diaphysis the respective values were 0.5 (0.4, 0.7) nmol Gd/g, 1.0 (0.8, 1.3) nmol Gd/g, and 2.7 (2.1, 3.5) nmol Gd/g. Elemental imaging of the femur obtained in this in vivo study revealed no Gd containing structures in the mineralized bone for gadoquatrane (< 1 nmol Gd/g). For gadopiclenol, a visible thin layer of Gd concentration (interquartile range [IQR]: 17-38 nmol Gd/g, maximum value ~80 nmol Gd/g) in the subcortical layer of the bone was observed. The same layer contained a lower Gd concentration for gadobu","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"768-778"},"PeriodicalIF":8.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12490335/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144005062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gadolinium Deposition in Bone Tissues After Contrast-enhanced Magnetic Resonance Imaging: A Comprehensive Review.","authors":"Nathalie Fretellier, Jean-Marc Idée, Marlène Rasschaert, Cécile Factor, Aart J Van der Molen","doi":"10.1097/RLI.0000000000001208","DOIUrl":"10.1097/RLI.0000000000001208","url":null,"abstract":"<p><p>Over the past 15 years, significant advancements have been made in understanding the pharmacology and toxicology of gadolinium-based contrast agents (GBCAs), widely used in magnetic resonance imaging (MRI). This review focuses on the fate of gadolinium cation (Gd 3+ ) in bone tissues. The evidence indicates that Gd 3+ can persist in bone for extended periods, with higher retention observed for GBCAs with linear ligand structures as opposed to macrocyclic ones. The prolonged presence of Gd, with a significant proportion in species other than the initial intact injected GBCA form, raises concerns about potential toxicological effects, although no direct clinical consequences on bone physiology have been reported so far. This review discusses the complex interactions between Gd 3+ and bone matrix components, such as hydroxyapatite, collagen, and proteoglycans, which might contribute to the mechanisms of Gd retention. It also explores the potential for Gd to interfere with bone remodelling processes and cellular functions, as suggested by in vitro studies, and in comparison with that known for other rare earth elements (REE).</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"722-744"},"PeriodicalIF":8.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12490344/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144505688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symptoms Associated With Gadolinium Exposure: Different Patterns and Rates Between Linear and Macrocyclic Gadolinium-Based Contrast Agents.","authors":"Imran Shahid, Eric Lancelot","doi":"10.1097/RLI.0000000000001160","DOIUrl":"10.1097/RLI.0000000000001160","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Objective: &lt;/strong&gt;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 3 or more SAGE symptoms.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Materials and methods: &lt;/strong&gt;SAGE were identified from a review of the scientific literature, and the corresponding preferred terms (PTs) were searched in each system organ class recorded in the FDA Adverse Event Reporting System (FAERS). To ensure the comparability of data, 3 macrocyclic and 3 linear extracellular GBCAs currently approved for intravenous administration in the United States were considered. Only patients with 3 or more SAGE symptoms were included. SAGE weights, representing the percentage of SAGE symptoms among all adverse events collected over a 6-year period from 2014 to 2019, were calculated for each GBCA. The frequency of these symptoms to occur in sets of \"3 PT combinations\" was also analyzed. The 3 PT combinations were calculated by first selecting the PT with the highest occurrence for a GBCA and then combining it with all the PTs accounting for 5% or more of the total adverse events reported for the respective GBCA. This led to identify the most prevalent 3 PT combinations per GBCA. Moreover, in order to determine whether or not SAGE symptoms were specific to GBCAs, data for 4 water-soluble iodinated contrast media were also extracted from the FAERS database over the same period, using the SAGE list of symptoms as reference.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;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 agents, the most prevalent 3 PT combinations of SAGE symptoms were reported in 152-164 occurrences, whereas for the macrocyclic agents, this range was significantly lower (1-13 occurrences). Moreover, all these agents could be categorized in 3 groups with different patterns of 3 PT combinations (ie, [gadodiamide and gadopentetate dimeglumine], [gadobenate dimeglumine and gadoteridol], and [gadoterate dimeglumine and gadobutrol]). The most prevalent PTs were found to be \"pain,\" \"arthralgia,\" and \"headache\" in each group, respectively.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;The global SAGE weights were significantly lower for the macrocyclic GBCAs as compared with the linear GBCAs. Moreover, the frequency of occurrence of 3 PT combinations was notably lower with the macrocyclic agents and comparable to the iodinated contrast media, indicating that SAGE may be negligible for this class of GBCAs. Different patterns of 3 PT combinations were also observed among the GBCAs involved in this study. A causal relationship could not be established between SAGE and the corresponding GBCAs, therefore, further research on this t","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"745-752"},"PeriodicalIF":7.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12490337/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Current Research and Development in the Field of Magnetic Resonance Contrast Media.","authors":"Val M Runge","doi":"10.1097/RLI.0000000000001206","DOIUrl":"10.1097/RLI.0000000000001206","url":null,"abstract":"<p><p>The next-generation, high relaxivity, gadolinium-based contrast agents (GBCAs) are discussed, together with new studies of safety, improvements in MR technique, and the ongoing development of additional agents. It is likely that the next generation agents, gadopiclenol and gadoquatrane, will largely replace the current standards, the macrocyclic gadolinium chelates, despite the excellent safety profile and very high stability of the latter. In the Group of Seven (G7) nations, which includes Canada, France, Germany, Italy, Japan, the United Kingdom and the United States, use of the linear gadolinium chelates has largely ceased, due to concerns regarding their relative instability as compared to the macrocyclic agents and the deposition of gadolinium that occurs in many tissues, including brain and bone, following their injection. Manganese-based compounds are once again being investigated, a field largely untouched since the initial development of clinical MR contrast media in the 1980s. Their potential impact on clinical imaging is, however, unclear. New information continues to emerge regarding differences in stability of the gadolinium-based agents. Artificial intelligence and deep learning techniques are maturing and are discussed briefly, given their potential and recent clinical application involving MR contrast media.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"709-710"},"PeriodicalIF":8.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144575490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reliability of Whole-Liver Liver-Fat-Quantification Between Deep Learning-Accelerated and Standard Volumetric Interpolated Breath-hold Examination Dixon Sequences in a Prospective Oncology Cohort.","authors":"Stephan Rau, Anna Fink, Ralph Strecker, Marcel Dominik Nickel, Lea Jigme Michel, Vlad Sacalean, Kai Falko Kästingschäfer, David Klemm, Alexander Rau, Fabian Bamberg, Jakob Weiss, Maximilian Frederik Russe","doi":"10.1097/RLI.0000000000001242","DOIUrl":"10.1097/RLI.0000000000001242","url":null,"abstract":"<p><strong>Objective: </strong>To evaluate the impact of accelerated, deep learning-based reconstructed T1-weighted VIBE Dixon images on fat-signal fraction (FSF) quantification compared with standard protocols.</p><p><strong>Methods: </strong>In this prospective single-center study, patients undergoing clinically indicated abdominal MRI underwent 3 T1-weighted VIBE acquisitions on a 1.5 T scanner: a standard sequence and 2 accelerated sequences (\"fast\" and \"ultra-fast\"). The accelerated scans employed higher CAIPIRINHA parallel imaging factors, partial Fourier sampling, and deep learning-based image reconstruction. Subsequently, whole-liver FSF was determined using a validated automated liver segmentation tool for in-phase and opposed-phase reconstructions. The quality of segmentation was assessed visually and by comparing liver volumes. Statistical analyses included calculation of mean absolute error and Spearman's correlation for FSF agreement.</p><p><strong>Results: </strong>Between March 2025 and May 2025, 60 patients (mean age, 63.7 ± 13.9 y; 55% females) were enrolled. Acquisition times were 15 seconds for the standard sequence and 10 and 6 seconds for fast and ultra-fast sequences, respectively. The whole liver segmentations from the fast and ultra-fast sequences showed high correlations (ρ > 0.975, both P < 0.001) with minimal mean absolute error of 1.1% and 1.5% from the standard sequence. The liver fat quantification showed high concordance across protocols, too: median FSF was 2.3% (standard), 2.6% (fast), and 2.4% (ultra-fast), with a mean absolute error <0.6% from standard for both accelerated protocols (all ρ > 0.92, P < 0.001).</p><p><strong>Conclusions: </strong>Liver fat quantification using highly accelerated, deep learning-enhanced MRI sequences enables reliable assessment of liver fat content with a significant reduction in scan time in low fat-fraction ranges.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.9,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13117532/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145312833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving Spatial Accuracy of MRI in the Presence of Metal-induced Geometric Distortions.","authors":"Hao Li, Ali C Özen, Mathias Nittka, Arne Lauer, Marianne Schell, Fabian Preisner, Michael O Breckwoldt, Dominik F Vollherbst, Martin Bendszus, Sabine Heiland, Tim Hilgenfeld","doi":"10.1097/RLI.0000000000001240","DOIUrl":"10.1097/RLI.0000000000001240","url":null,"abstract":"<p><strong>Objectives: </strong>To identify sequences and protocols for minimal metal-induced geometric distortion (MD) for improved spatial accuracy in MRI.</p><p><strong>Materials and methods: </strong>A 3D lattice phantom containing a stainless-steel bracket or a crown-supported titanium implant was scanned using 6 MRI sequences (TSE, SEMAC, CS-SEMAC, SPACE, VIBE, and research sequence MSVAT-SPACE) in a 3T system. MD was assessed at 9360 crossing points as Euclidean distance using a standardized algorithm. MD was analyzed by total MD, affected volume (AV) at various thresholds, and directional dependency. Statistical analysis was performed by one-way ANOVA.</p><p><strong>Results: </strong>For the stainless-steel bracket, TSE showed the highest total MD among all sequences (2187±297 mm, P<0.01) and maximum displacement (>4 mm), with 467 mL AV at MD>0.5 mm. CS-SEMAC and SEMAC yielded the lowest MD among all sequences (469±75 mm and 502±154 mm, P<0.01) and the smallest AV (55 mL and 45 mL) at MD>0.5 mm. 3D sequences exhibited intermediate performance with no significant difference (MSVAT-SPACE/VIBE/SPACE: 1569±204 mm/1137±71 mm/1513±143 mm; P>0.08). For the crown-supported titanium implant, all sequences showed reduced MD (<440 mm) and AV (<71 mL at MD>0.5 mm), while VIBE yielded a comparable AV (65 mL) but the highest MD (615 mm). MD was direction-dependent, particularly for the stainless-steel bracket, being highest along frequency-encoding direction (P<0.002); TSE also showed significantly higher MD in slice direction (P=0.0071), while distortions in phase direction were consistently lower.</p><p><strong>Conclusions: </strong>Susceptibility artifact reduction sequences, particularly SEMAC and CS-SEMAC, effectively reduce total-MD by 79% and AV by 90%. Distortion varies by encoding direction and is most severe along the frequency-encoding axis, highlighting the importance of sequence and parameter selection for accurate MRI near metal implants.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.9,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13117564/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145280241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multicontrast Multiphase Intestinal Imaging Using Photon-Counting CT: A Feasibility Study in Rats.","authors":"Jonas Neumann, Gregor Jost, Ralf Gutjahr, Tristan Nowak, Jessica Lohrke, Bernhard Schmidt, Joachim von Zanthier, Hubertus Pietsch","doi":"10.1097/RLI.0000000000001241","DOIUrl":"10.1097/RLI.0000000000001241","url":null,"abstract":"<p><strong>Objectives: </strong>The aim of this study is to validate a 3-material decomposition algorithm for distinguishing between 2 contrast media (CM) (iodine-based and tungsten-based) and water in vivo using a commercial photon-counting CT (PCCT) unit, able to acquire 4 energy thresholds simultaneously.</p><p><strong>Materials and methods: </strong>Six healthy rats were imaged during different CM distribution phases with both iodine-based and tungsten-based CM present in the animals, one administered orally and one intravenously. Material decomposition was used to compute quantitative contrast maps, virtual noncontrast (VNC) maps, and virtual monoenergetic images (VMI). The mean enhancement in CM-filled regions and in CM-free muscle was measured. This prospective preclinical study was conducted in accordance with the German Animal Welfare Act guidelines and with the approval of the local state animal welfare committee.</p><p><strong>Results: </strong>Iodine-filled regions were exclusively enhanced (P<0.001) in the iodine map. Tungsten-filled regions were exclusively enhanced (P<0.001) in the tungsten map. VNC maps of a 3-material decomposition received no additional enhancement by CM. VMI, incorporating both iodine and tungsten CM, of different energy levels indicated the K-edge of tungsten.</p><p><strong>Conclusions: </strong>This study successfully demonstrated the capability of PCCT combined with material decomposition to delineate 2 CM and water in rats. The contrast dynamics of the 2 CM in the vessels (aorta and vena cava) and intestines were successfully reproduced in the CM maps. VNC maps may omit the need for CT scans before contrast administration. VMI revealed distinct energy-dependent attenuation profiles of the given materials.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13117563/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145206618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"T1 Relaxation-Enhanced Steady-State Acquisition With Radial k-Space Sampling: A Novel Family of Pulse Sequences for Motion-Robust Volumetric T1-Weighted MRI With Improved Lesion Conspicuity.","authors":"Ruoxun Zi, Robert R Edelman, Christoph Maier, Mahesh Keerthivasan, Riccardo Lattanzi, Daniel K Sodickson, Kai Tobias Block","doi":"10.1097/RLI.0000000000001185","DOIUrl":"10.1097/RLI.0000000000001185","url":null,"abstract":"<p><strong>Objectives: </strong>Magnetization-prepared rapid gradient-echo (MP-RAGE) sequences are routinely acquired for brain exams, providing high conspicuity for enhancing lesions. Vessels, however, also appear bright, which can complicate the detection of small lesions. T1RESS (T1 relaxation-enhanced steady-state) sequences have been proposed as an alternative to MP-RAGE, offering improved lesion conspicuity and suppression of blood vessels. This work aims to evaluate the performance of radial T1RESS variants for motion-robust contrast-enhanced brain MRI.</p><p><strong>Materials and methods: </strong>Radial stack-of-stars sampling was implemented for steady-state free-precession-based rapid T1RESS acquisition with saturation recovery preparation. Three variants were developed using a balanced steady-state free-precession readout (bT1RESS), an unbalanced fast imaging steady precession (FISP) readout (uT1RESS-FISP), and an unbalanced reversed FISP readout (uT1RESS-PSIF). Image contrast was evaluated in numerical simulations and phantom experiments. The motion robustness of radial T1RESS was demonstrated with a motion phantom. Four patients and six healthy volunteers were scanned at 3 T and 0.55 T. Extensions were developed combining T1RESS with GRASP for dynamic imaging, with GRAPPA for accelerated scans, and with Dixon for fat/water separation.</p><p><strong>Results: </strong>In simulations and phantom scans, uT1RESS-FISP provided higher signal intensity for regions with lower T1 values (<500 ms) compared with MP-RAGE. In motion experiments, radial uT1RESS-FISP showed fewer artifacts than MP-RAGE and Cartesian uT1RESS-FISP. In patients, both unbalanced uT1RESS variants provided higher lesion conspicuity than MP-RAGE. Blood vessels appeared bright with MP-RAGE, gray with uT1RESS-FISP, and dark with uT1RESS-PSIF. At 0.55 T, bT1RESS provided high signal-to-noise ratio T1-weighted images without banding artifacts. Lastly, dynamic T1RESS images with a temporal resolution of 10.14 seconds/frame were generated using the GRASP algorithm.</p><p><strong>Conclusions: </strong>Radial T1RESS sequences offer improved lesion conspicuity and motion robustness and enable dynamic imaging for contrast-enhanced brain MRI. Both uT1RESS variants showed higher tumor-to-brain contrast than MP-RAGE and may find application as alternative techniques for imaging uncooperative patients with small brain lesions.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"658-668"},"PeriodicalIF":7.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12353590/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PixelPrint 4D : A 3D Printing Method of Fabricating Patient-Specific Deformable CT Phantoms for Respiratory Motion Applications.","authors":"Jessica Y Im, Neghemi Micah, Amy E Perkins, Kai Mei, Michael Geagan, Leonid Roshkovan, Peter B Noël","doi":"10.1097/RLI.0000000000001182","DOIUrl":"10.1097/RLI.0000000000001182","url":null,"abstract":"<p><strong>Objectives: </strong>Respiratory motion poses a significant challenge for clinical workflows in diagnostic imaging and radiation therapy. Many technologies such as motion artifact reduction and tumor tracking have been developed to compensate for its effect. To assess these technologies, respiratory motion phantoms (RMPs) are required as preclinical testing environments, for instance, in computed tomography (CT). However, current CT RMPs are highly simplified and do not exhibit realistic tissue structures or deformation patterns. With the rise of more complex motion compensation technologies such as deep learning-based algorithms, there is a need for more realistic RMPs. This work introduces PixelPrint 4D , a 3D printing method for fabricating lifelike, patient-specific deformable lung phantoms for CT imaging.</p><p><strong>Materials and methods: </strong>A 4DCT dataset of a lung cancer patient was acquired. The volumetric image data of the right lung at end inhalation was converted into 3D printer instructions using the previously developed PixelPrint software. A flexible 3D printing material was used to replicate variable densities voxel-by-voxel within the phantom. The accuracy of the phantom was assessed by acquiring CT scans of the phantom at rest, and under various levels of compression. These phantom images were then compiled into a pseudo-4DCT dataset and compared to the reference patient 4DCT images. Metrics used to assess the phantom structural accuracy included mean attenuation errors, 2-sample 2-sided Kolmogorov-Smirnov (KS) test on histograms, and structural similarity index (SSIM). The phantom deformation properties were assessed by calculating displacement errors of the tumor and throughout the full lung volume, attenuation change errors, and Jacobian errors, as well as the relationship between Jacobian and attenuation changes.</p><p><strong>Results: </strong>The phantom closely replicated patient lung structures, textures, and attenuation profiles. SSIM was measured as 0.93 between the patient and phantom lung, suggesting a high level of structural accuracy. Furthermore, it exhibited realistic nonrigid deformation patterns. The mean tumor motion errors in the phantom were ≤0.7 ± 0.6 mm in each orthogonal direction. Finally, the relationship between attenuation and local volume changes in the phantom had a strong correlation with that of the patient, with analysis of covariance yielding P  = 0.83 and f  = 0.04, suggesting no significant difference between the phantom and patient.</p><p><strong>Conclusions: </strong>PixelPrint 4D facilitates the creation of highly realistic RMPs, exceeding the capabilities of existing models to provide enhanced testing environments for a wide range of emerging CT technologies.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"636-646"},"PeriodicalIF":7.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12353425/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}