Investigative Radiology最新文献

{"title":"Epineural Scarring Visualization and Noninvasive Quantification of a Severe Posttraumatic Complication: An Experimental Magnetic Resonance Neurography Study.","authors":"Merle Brunnée, Martin Aman, Maximilian Mayrhofer-Schmid, Manuel Fischer, Simeon C Daeschler, Tess Klemm, Ulrich Kneser, Kianush Karimian-Jazi, Michael O Breckwoldt, Leila Harhaus, Sabine Heiland, Martin Bendszus, Arne H Boecker, Daniel Schwarz","doi":"10.1097/RLI.0000000000001132","DOIUrl":"10.1097/RLI.0000000000001132","url":null,"abstract":"<p><strong>Aim: </strong>Peripheral nerve scarring is a severe yet common complication following nerve injury or surgery that can lead to impaired nerve function, including chronic pain and sensory or motor deficits. In this study, we aimed to establish high-resolution magnetic resonance neurography (MRN) to accurately visualize and monitor de novo-formed epineural fibrotic adhesions (EFAs) of the sciatic nerve in a rat nerve injury model.</p><p><strong>Methods: </strong>Employing an established model to induce overshooting EFA, the study included 3 experimental groups of animals (n = 6 each): a positive control group (PC), an intervention group (IG), and a sham group. All groups underwent surgical nerve exposure: both PC and IG received an application of 10 μL 2.5% glutaraldehyde to induce EFA, but only IG received an additional preventive wrapping of the nerve with a collagen-containing matrix. Magnetic resonance imaging was performed 6, 8, and 12 weeks postoperatively using a standardized protocol including T2w and T1w without and with contrast media. Motor function and nerve regeneration was assessed using the visual static sciatic index. Histological specimens were obtained 12 weeks postoperatively and correlated with imaging.</p><p><strong>Results: </strong>On high-resolution MRN, prominently contrast-enhancing epineural sleeves were present in vivo, which corresponded to histologically confirmed EFA (ratio of EFA to nerve area MRN 1.512 ± 0.106 vs histological ratio 1.459 ± 0.208, nonsignificant). As expected, average EFA in IG (0.310 ± 0.118 mm 2 ) was smaller than in PC (0.909 ± 0.212 mm 2 , P < 0.01). Also, the average EFA in sham (0.386 ± 0.030 mm 2 ) was less pronounced than in PC ( P < 0.01). There was no significant difference in the average EFA between IG und sham. The EFA correlated with the functional outcome, which was measured by visual static sciatic index (correlation coefficient -0.59, P < 0.05).</p><p><strong>Conclusions: </strong>The results of the present study for the first time confirm the clinical observation that epineural thickening on contrast-enhanced T1w imaging following manipulation to a nerve indeed corresponds to overshooting epineural scarring, which may be linked to impaired nerve function. This can be followed noninvasively in vivo over time providing an important basis for clinical decision-making in cases where further invasive therapies may be necessary.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"275-280"},"PeriodicalIF":7.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142604397","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":"A Comprehensive and Repeatable Contrast-Enhanced Ultrasound Quantification Approach for Clinical Evaluations of Tumor Blood Flow.","authors":"Connor Krolak, Angela Wei, Marissa Shumaker, Manjiri Dighe, Michalakis Averkiou","doi":"10.1097/RLI.0000000000001127","DOIUrl":"10.1097/RLI.0000000000001127","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Objective: &lt;/strong&gt;The aim of this study is to define a comprehensive and repeatable contrast-enhanced ultrasound (CEUS) imaging protocol and analysis method to quantitatively assess lesional blood flow. Easily repeatable CEUS evaluations are essential for longitudinal treatment monitoring. The quantification method described here aims to provide a structure for future clinical studies.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Materials and methods: &lt;/strong&gt;This retrospective analysis study included liver CEUS studies in 80 patients, 40 of which contained lesions (primarily hepatocellular carcinoma, n = 28). Each patient was given at least 2 injections of a microbubble contrast agent, and 60-second continuous loops were acquired for each injection to enable evaluation of repeatability. For each bolus injection, 1.2 mL of contrast was delivered, whereas continuous, stationary scanning was performed. Automated respiratory gating and motion compensation algorithms dealt with breathing motion. Similar in size regions of interest were drawn around the lesion and liver parenchyma, and time-intensity curves (TICs) with linearized image data were generated. Four bolus transit parameters, rise time ( RT ), mean transit time ( MTT ), peak intensity ( PI ), and area under the curve ( AUC ), were extracted either directly from the actual TIC data or from a lognormal distribution curve fitted to the TIC. Interinjection repeatability for each parameter was evaluated with coefficient of variation. A 95% confidence interval was calculated for all fitted lognormal distribution curve coefficient of determination ( R2 ) values, which serves as a data quality metric. One-sample t tests were performed between values obtained from injection pairs and between the fitted lognormal distribution curve and direct extraction from the TIC calculation methods to establish there were no significant differences between injections and measurement precision, respectively.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Average interinjection coefficient of variation with both the fitted curve and direct calculation of RT and MTT was less than 21%, whereas PI and AUC were less than 40% for lesion and parenchyma regions of interest. The 95% confidence interval for the R2 value of all fitted lognormal curves was [0.95, 0.96]. The 1-sample t test for interinjection value difference showed no significant differences, indicating there was no relationship between the order of the repeated bolus injections and the resulting parameters. The 1-sample t test between the values from the fitted lognormal distribution curve and the direct extraction from the TIC calculation found no statistically significant differences (α = 0.05) for all perfusion-related parameters except lesion and parenchyma PI and lesion MTT .&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;The scanning protocol and analysis method outlined and validated in this study provide easily repeatable quantitative evaluations of lesional blood flow with bolus transit par","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"281-290"},"PeriodicalIF":7.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11888899/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142465523","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":"Imaging of Cardiovascular Implantable Electronic Device Leads With Photon-Counting Detector Computed Tomography.","authors":"Simon Schalla, Joachim E Wildberger, Mitch J F G Ramaekers, Casper Mihl, Michael C McDermott, Lion Stammen, Kevin Vernooy, Thomas G Flohr","doi":"10.1097/RLI.0000000000001177","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001177","url":null,"abstract":"<p><strong>Objectives: </strong>Computed tomography (CT) imaging of cardiovascular implantable electronic device (CIED) leads is currently hampered by large metal artifacts. Recently, photon-counting detector CT (PCD-CT) has been clinically introduced, offering high-resolution imaging with thin slice thicknesses and improved contrast-to-noise ratios. Suspected complications of CIED such as perforation, infection and venous obstruction could potentially be imaged with PCD-CT if metal artifacts were effectively reduced through adapted scan protocols and iterative metal artifact reduction algorithms (IMAR). The study evaluated the impact of various scan and reconstruction parameters, including different IMAR settings, on CIED lead visualization with PCD-CT in order to develop an optimized scan and reconstruction protocol for imaging leads.</p><p><strong>Materials and methods: </strong>Five different CIED leads were evaluated in a nonbeating heart phantom using a dual-source PCD-CT with electrocardiography-gated spectral standard resolution (collimation 144 × 0.4 mm) and nonspectral ultra-high resolution (UHR) mode (collimation 120 × 0.2 mm) spiral data acquisition. One scan was performed for each lead and each acquisition mode. Images were reconstructed with different slice thicknesses (0.2 mm, 0.4 mm, 0.6 mm), convolution kernels (Bv40, Bv44, Bv48, and Bv56), virtual monoenergetic energy levels (60-140 keV in steps of 10 keV), without and with different IMAR settings. The extent of metal artifacts was objectively evaluated using 4 different parameters. Additionally, 3 observers subjectively assessed image quality using a 5-point scale.</p><p><strong>Results: </strong>Metal artifacts increased with sharper kernels and higher keV levels in virtual monoenergetic reconstructions. The artifacts were not dependent on slice thickness. No significant differences in metal artifacts were observed between UHR and standard-resolution scans when using similar reconstruction parameters. IMAR effectively reduced artifacts across all kernels, slice thicknesses, and keV levels, with the \"neuro coils\" setting showing the best performance. Subjective analysis of image quality revealed that thinnest slices and sharpest kernels (0.2 mm, Bv56) allowed for better delineation of fine structures, such as the shape of helices, while reconstructions with thicker slices and softer kernels (0.6 mm, Bv40) were preferred for visualizing general lead appearance and adjacent anatomical structures.</p><p><strong>Conclusions: </strong>Ultra-high and standard resolution PCD-CT with IMAR enables good-quality imaging of CIED leads, showing even small details without compromising the visibility of nearby structures. A dedicated acquisition and reconstruction protocol comprising an UHR scan with 2 reconstructions (0.2 mm/Bv56 and 0.6 mm/Bv40, using IMAR) appears optimal for PCD-CT imaging of CIED leads.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143730025","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":"Every Drop (Photon) Counts: Current Applications and Future Challenges of Photon-Counting Detector CT in Abdominal Imaging.","authors":"Domenico De Santis, Antonella Del Gaudio, Curzio Santangeli, Federica Fanelli, Fiammetta Pacelli, Lucrezia Capece Minutolo Del Sasso, Marta Zerunian, Michela Polici, Tiziano Polidori, Francesco Pucciarelli, Daniele Marin, Andrea Laghi, Damiano Caruso","doi":"10.1097/RLI.0000000000001178","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001178","url":null,"abstract":"<p><strong>Abstract: </strong>Photon-counting detector computed tomography (PCD-CT) is a breakthrough innovation over conventional single-energy and dual-energy CT equipped with energy-integrating detectors (EID). Because of increased spatial resolution and improved material differentiation, PCD-CT aims at improving the diagnosis of various abdominal conditions. This technology offers several advantages over EID-based CT scanners, including higher spatial and contrast resolution, reduced electronic noise, and low radiation dose exposure. Additionally, because spectral information is generated within the detectors, PCD-CT offers the possibility of routine spectral examinations and refines material decomposition through available multienergy imaging, further enhancing tissue characterization and image contrast. With most scientific literature focused on cardiovascular applications, abdominal imaging is an open field for technical and clinical research in PCD-CT. This review aims to provide a general overview of the technical principles of PCD-CT, its applications in abdominal imaging, and to summarize the main literature findings of its clinical applications in the liver, pancreas, adrenals, genitourinary system, bowel, peritoneum, and abdominal vessels. We will also highlight the pros and cons observed in clinical practice and offer insights into potential future developments of PCD-CT in abdominal imaging.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143730021","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":"Fixed Versus Patient-Specific Trigger Delay in High-Pitch Computed Tomography Angiography of the Aorta Prior to Transcatheter Aortic Valve Implantation: Assessment of Image Quality and Homogeneity of Vessel Enhancement.","authors":"Sidre Sahin-Uzuner, Foroud Aghapour Zangeneh, Goncalo De Almeida, Oezlem Krzystek, Maria Paslak, Jakob Heimer, Ralf Gutjahr, Thomas Sartoretti, Tilo Niemann, André Euler","doi":"10.1097/RLI.0000000000001176","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001176","url":null,"abstract":"<p><strong>Objective: </strong>The aim of the study is to compare the image quality and homogeneity of vessel enhancement in high-pitch CT-angiography of the aorta (CTA) prior to transcatheter aortic valve implantation between bolus tracking with a fixed trigger delay and bolus tracking with a patient-specific trigger delay.</p><p><strong>Materials and methods: </strong>In this retrospective study, consecutive patients who received a CTA of the aorta prior to transcatheter aortic valve implantation between January 2023 and June 2024 were included. Patients were imaged using either bolus tracking and a fixed trigger delay (Group A; 15 seconds) or bolus tracking and a patient-specific trigger delay (Group B; FAST Bolus; Siemens Healthineers AG). The same contrast injection and scan protocol were used in both groups. Vessel enhancement was measured at multiple craniocaudal locations. Subjective image quality was assessed by 2 readers using 5-point Likert scales. Likert scores were analyzed using Wilcoxon rank-sum tests. Enhancement was assessed with a mixed-effects model.</p><p><strong>Results: </strong>Sixty-five patients (28 females) were assessed in each group. Patient demographics (both 74 ± 12 years; P = 0.58, body mass index: 26.0 vs 26.2 kg/m2; P = 0.79) and radiation dose (CTDIvol: 3.4 vs 3.5 mGy; P = 0.55) did not differ significantly between the two groups. Mean CT attenuation was 489 HU versus 469 HU in the ascending aorta and 428 HU versus 464 HU in the common femoral artery for fixed and patient-specific delays, respectively. Enhancement in the femoral arteries was significantly lower in the fixed delay group (P < 0.05), while there was no significant difference at other vessel locations. Diagnostic image quality and enhancement at the femoral artery were rated significantly better for the patient-specific trigger delay by one reader (both P < 0.05).</p><p><strong>Conclusions: </strong>Bolus tracking with a patient-specific trigger delay improved the craniocaudal homogeneity of vessel enhancement and subjective image quality at the distal access site as compared to bolus tracking with a fixed trigger delay in high-pitch CTA prior to TAVI.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143669842","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":"Emerging Trends and Innovations in Radiologic Diagnosis of Thoracic Diseases.","authors":"Jiyoung Song, Eui Jin Hwang, Soon Ho Yoon, Chang Min Park, Jin Mo Goo","doi":"10.1097/RLI.0000000000001179","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001179","url":null,"abstract":"<p><strong>Abstract: </strong>Over the past decade, Investigative Radiology has published numerous studies that have fundamentally advanced the field of thoracic imaging. This review summarizes key developments in imaging modalities, computational tools, and clinical applications, highlighting major breakthroughs in thoracic diseases-lung cancer, pulmonary nodules, interstitial lung disease (ILD), chronic obstructive pulmonary disease (COPD), COVID-19 pneumonia, and pulmonary embolism-and outlining future directions.Artificial intelligence (AI)-driven computer-aided detection systems and radiomic analyses have notably improved the detection and classification of pulmonary nodules, while photon-counting detector CT (PCD-CT) and low-field MRI offer enhanced resolution or radiation-free strategies. For lung cancer, CT texture analysis and perfusion imaging refine prognostication and therapy planning. ILD assessment benefits from automated diagnostic tools and innovative imaging techniques, such as PCD-CT and functional MRI, which reduce the need for invasive diagnostic procedures while improving accuracy. In COPD, dual-energy CT-based ventilation/perfusion assessment and dark-field radiography enable earlier detection and staging of emphysema, complemented by deep learning approaches for improved quantification. COVID-19 research has underscored the clinical utility of chest CT, radiographs, and AI-based algorithms for rapid triage, disease severity evaluation, and follow-up. Furthermore, tuberculosis remains a significant global health concern, highlighting the importance of AI-assisted chest radiography for early detection and management. Meanwhile, advances in CT pulmonary angiography, including dual-energy reconstructions, allow more sensitive detection of pulmonary emboli.Collectively, these innovations demonstrate the power of merging novel imaging technologies, quantitative functional analysis, and AI-driven tools to transform thoracic disease management. Ongoing progress promises more precise and personalized diagnostic and therapeutic strategies for diverse thoracic diseases.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143663442","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":"Developing Magnetic Resonance Imaging Biomarkers of Neuroinflammation, Cognitive Impairment, and Survival Outcomes for Radiotherapy-Induced Brain Injury in a Preclinical Mouse Model.","authors":"Maya Teitz, Esteban Velarde, Xiaoju Yang, Shana Lee, Kristen Lecksell, Chantelle Terrillion, Adnan Bibic, Ethel J Ngen","doi":"10.1097/RLI.0000000000001173","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001173","url":null,"abstract":"<p><strong>Objective: </strong>Radiotherapy-induced brain injury (RIBI) is a chronic side effect that affects up to 90% of brain tumor survivors treated with radiotherapy. Here, we used multiparametric magnetic resonance imaging (MRI) to identify noninvasive and clinically translatable biomarkers of RIBI.</p><p><strong>Method: </strong>8-week-old female, immune competent BALB/c mice were stereotactically irradiated with a single dose of 80 Gy, at a dose rate of 1.7 Gy/minute. The irradiated mice were then monitored longitudinally with MRI, behavioral tests of learning and memory, and immunohistochemistry, in comparison to nonirradiated mice.</p><p><strong>Results: </strong>Three types of MRI biomarkers of RIBI were identified. A contrast-enhanced T1-weighted MRI biomarker was identified as being best suited to detect the onset of injury, by detecting changes in the blood-brain barrier (BBB) permeability. Maximum BBB permeability (18.95 ± 1.75) was detected with contrast-enhanced T1-weighted MRI at 1-month postirradiation in irradiated mice (P < 0.0001, n = 3). Interestingly, maximum neuroinflammation (24.14 ± 6.72) was also detected using IBA1 and CD68 immunohistochemistry at 1-month postirradiation in irradiated mice (P = 0.0041, n = 3). This simultaneous maximum BBB permeability and neuroinflammation detection also coincided with the detection of the onset of transient cognitive impairment, detected using the fear-conditioning behavioral test at 1-month postirradiation in irradiated mice compared to nonirradiated mice (P = 0.0017, n = 10). A T2-weighted MRI hyperintensity biomarker was also identified, and determined to be best suited to detect intermediate injury. Maximum T2-weighted MRI hyperintensity (3.97 ± 2.07) was detected at 2-month postirradiation in the irradiated mice compared to nonirradiated mice (P = 0.0368, n = 3). This T2-weighted MRI hyperintensity also correlated with maximum astrogliosis (9.92 ± 4.21), which was also detected at 2-month postirradiation using GFAP immunohistochemistry in the irradiated mice compared to nonirradiated mice (P = 0.0215, n = 3). Finally, T2-weighted and T2*-weighted MRI hypointensity biomarkers were identified as being best suited to detect late injury, from 4-month postirradiation. These biomarkers correlated with increased iron deposition from late vascular damage, which was validated with Perls' Prussian blue histology (P < 0.05, n = 3). These hypointense MRI biomarkers of late injury also preceded significant weight loss, severe cognitive impairment, and decreased survival in the irradiated mice compared to the nonirradiated mice.</p><p><strong>Conclusions: </strong>Here, we identified 3 types of translational MRI biomarkers of RIBI that could enable the noninvasive longitudinal evaluation of potential RIBI prophylactic and therapeutic agents. These translational MRI biomarkers could also play a pivotal role in the management of RIBI in brain tumor survivors.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143648471","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":"Performance of an Intravascular Tantalum Oxide-Based Nanoparticle Computed Tomography Contrast Agent in Preclinical Hepatic Tumor Detection.","authors":"Maurice M Heimer, Yuxin Sun, Peter J Bonitatibus, Johanna Luitjens, Cheng W Hong, Nikki Okwelogu, Sina Houshmand, Theresia Aschauer, Clemens C Cyran, Michael Ingrisch, Brian C Bales, Dan E Meyer, Benjamin M Yeh","doi":"10.1097/RLI.0000000000001175","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001175","url":null,"abstract":"<p><strong>Background: </strong>Noniodinated intravenous contrast agents have shown significant potential to improve computed tomography (CT) imaging; however, in vivo evidence for impact on lesion detection remains scarce.</p><p><strong>Purpose: </strong>The aim of the study was to compare a novel intravenous carboxybetaine zwitterionic-coated tantalum oxide (TaCZ) nanoparticle contrast agent to clinical iodinated contrast agent for the detection of liver tumors in a rabbit tumor model at CT.</p><p><strong>Methods: </strong>Following hepatic implantation of VX2 tumors, n = 10 rabbits were repeatedly scanned on a clinical CT system before and at 40, 105, and 180 seconds after intravenous contrast injection of 540 mg element (Ta or I) per kilogram of body weight using TaCZ or iopamidol. After contrast elimination, imaging was repeated with the other contrast agent in each rabbit. Findings were compared to gross pathology. Three readers independently reviewed n = 114 randomized image series for hepatic tumors and rated conspicuity on a 5-point scale (1 = barely visible to 4 = obvious; 0 = not detected). Regions of interest drawn by readers were used to calculate contrast to noise ratio. Metrics were compared between contrast agents for different tumor size categories (3-6 mm, >6-11 mm, >11-14 mm, >14 mm) and for venous scan delays between contrast agents.</p><p><strong>Results: </strong>TaCZ provided higher hepatic contrast enhancement resulting in superior Contrast-to-noise ratio (CNR) of hepatic tumors at all examined venous contrast delays (5.7-6.9 vs 3.9-4.5; all P < 0.001) compared to iopamidol. This translated into improved overall sensitivity (all P < 0.001) and detection of small hepatic tumors ≤11 mm (all P≤0.002). In addition, compared to iopamidol, TaCZ showed higher tumor conspicuity in all subgroups. Larger lesion size and early contrast delay were associated with improved lesion detection for both contrast agents.</p><p><strong>Conclusions: </strong>Experimental TaCZ nanoparticles showed higher hepatic contrast enhancement and improved the detection and conspicuity of hepatic tumors at all sizes and scan delays compared to iopamidol, with sustained intense contrast enhancement in delayed venous phase up to at least 180 seconds.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657182","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":"The Discovery of Gadopiclenol: An Example of Rational Drug Design?","authors":"Marc Port","doi":"10.1097/RLI.0000000000001169","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001169","url":null,"abstract":"<p><strong>Abstract: </strong>Gadopiclenol was initially developed as a high-relaxivity, nonspecific magnetic resonance imaging contrast agent to enhance image quality and thereby improve diagnostics. This design required a highly demanding Drug Target Profile, addressing not only relaxivity but also factors such as physicochemical properties of the injectable solution (viscosity, osmolality, heat sterilization compatibility), pharmacokinetics and toxicity, particularly related to the stability of the complex. These considerations led to a multiparametric molecular design based on a gadolinium complex characterized by the following features: (1) a macrocyclic, nonionic structure based on the PCTA framework with 2 water molecules in the inner sphere; (2) the introduction of steric constraints around the gadolinium to enhance stability and reduce relaxivity quenching by endogenous ions; (3) slowed rotational diffusion due to gadolinium's position at the center of the complex; and (4) the incorporation of 3 hydrophilic amino polyol pendant arms to ensure aqueous solubility, reduce binding with endogenous proteins, and enhance product safety.This rational design led to the creation of a first prototype, P03277V1. However, the occurrence of nephrogenic systemic fibrosis necessitated modifications to the Drug Target Profile, aimed at improving the complex's stability and reducing production costs. This was achieved through the discovery of an isomerization process for P03277V1, resulting in gadopiclenol, which demonstrated excellent kinetic stability.The rational design of gadopiclenol thus exemplifies the concept of Property-Based Drug Design used in medicinal chemistry. It also highlights that the complexity of designing a diagnostic agent is comparable to that of a therapeutic agent. Furthermore, the case of gadopiclenol illustrates that the medical positioning of a drug candidate can evolve during clinical development. Gadopiclenol's medical positioning shifted from being a product with high relaxivity to improve signal strength, to one intended for use at a half dose to limit gadolinium injection and minimize risks to patients, such as nephrogenic systemic fibrosis or accumulation in specific areas of the brain. Currently, gadopiclenol is approved for clinical use at a dose of 0.05 mmol/kg to minimize gadolinium exposure to patients. Whether the 0.1 mmol/kg dose can be used to enhance clinical diagnostics and improve patient management in the future remains to be seen.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604818","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":"The Effect of X-ray Dose Photon-Counting Detector Computed Tomography on Nodule Properties in a Lung Cancer Screening Cohort: A Prospective Study.","authors":"Bjarne Kerber, Falko Ensle, Jonas Kroschke, Cecilia Strappa, Ricarda Stolzmann-Hinzpeter, Christian Blüthgen, Marc Marty, Anna Rita Larici, Thomas Frauenfelder, Lisa Jungblut","doi":"10.1097/RLI.0000000000001174","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001174","url":null,"abstract":"<p><strong>Objectives: </strong>The aim of the study was to evaluate the effect of photon-counting detector (PCD-)CT dose reduction to x-ray equivalent levels on nodule detection, diameter, volume, and density compared to a low-dose reference standard using semiautomated and manual methods.</p><p><strong>Materials and methods: </strong>Between February and July 2023, 101 prospectively enrolled participants underwent noncontrast same-study low- and chest x-ray-dose CT scans using PCD-CT. Patients who were not referred for lung cancer screening or nodule follow-up, as well as those with nodules smaller than 5 mm in diameter, were excluded. Nodule detection and measurement of nodule diameters and volumes was semiautomatically performed for low- and x-ray-dose scans using computer-aided diagnosis software. Additionally, 2 blinded readers manually measured largest nodule diameters and examined nodule density. Nodules were classified using Lung-RADS v2022. Image quality was assessed with subjective and objective measures.</p><p><strong>Results: </strong>Mean CTDIvol for x-ray dose scans was 0.11 ± 0.03 mGy, compared to 0.65 ± 0.15 mGy for low-dose images (P < 0.001). One hundred seventy-two nodules larger than 5 mm were detected in 53 of the 101 participants (32 male, 61.6 ± 12.5 years; 21 female, 60.3 ± 12.5 years). The semiautomated method had high overall sensitivity for nodule detection (0.94) on x-ray dose scans, with a higher sensitivity for solid nodules (>0.95) and lower for subsolid nodules (>0.86). Nodules not detected on x-ray dose scans were significantly smaller. Semiautomated measurements underestimated nodule diameter for solid nodules on x-ray dose scans (P = 0.01), but no significant effect for nodule volume was found (P = 0.775). Readers rated nodule density less dense on x-ray dose scans (R1: P < 0.001, R2: P = 0.006). There was no significant difference in nodule diameter for both readers between scan doses (R1: P = 0.141; R2: P = 0.554). There were good to excellent correlations between semiautomated and reader nodule diameters. Agreement and accuracy between low-dose and x-ray dose Lung-RADS classifications across methods were good (Cohens' к = 0.73, 0.62, 0.76 for semiautomated method, R1 and R2; resp. Accuracy: 0.82, 0.78, 0.85). No Lung-RADS classification changes were observed with semiautomated volumetric measurements of nodules.</p><p><strong>Conclusions: </strong>Semiautomated nodule detection is highly sensitive in PCD-CT x-ray dose scans. Semiautomated nodule volume measurement is more robust to image quality changes than nodule diameter. Accurate semiautomated and manual nodule measurements are feasible on x-ray dose scans, but nodule density was in tendency underestimated. Nodule classification using Lung-RADS was shown to be accurate on x-ray dose scans.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143575710","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}