49 results match your criteria contrast agent-free

Organic Structure-Directing Agent-Free Synthesis of Mordenite-Type Zeolites Driven by Al-Rich Amorphous Aluminosilicates.

ACS Omega 2021 Mar 16;6(8):5176-5182. Epub 2021 Feb 16.

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.

Mordenite (MOR)-type zeolites with a Si/Al molar ratio of up to 13 with crystallite sizes of ca. 60 nm were successfully synthesized from Al-rich aluminosilicates with a Si/Al ratio of 2 and additional SiO under seed-assisted hydrothermal conditions for 6 h or longer without any organic structure-directing agents (OSDAs). In stark contrast, under the same hydrothermal conditions for 6 h, control experiments using starting reagent(s), such as Al-poor aluminosilicate, pure SiO, tetraethyl orthosilicate, and Al(NO), all of which are typically employed for zeolite synthesis, failed to yield MOR-type zeolites. Read More

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Quantitative three-dimensional collagen orientation analysis of human meniscus posterior horn in health and osteoarthritis using micro-computed tomography.

Osteoarthritis Cartilage 2021 Feb 13. Epub 2021 Feb 13.

Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland. Electronic address:

Objective: Knee osteoarthritis (OA) is associated with meniscal degeneration that may involve disorganization of the meniscal collagen fiber network. Our aims were to quantitatively analyze the microstructural organization of human meniscus samples in 3D using micro-computed tomography (μCT), and to compare the local microstructural organization between OA and donor samples.

Method: We collected posterior horns of both medial and lateral human menisci from 10 end-stage medial compartment knee OA patients undergoing total knee replacement (medial & lateral OA) and 10 deceased donors without knee OA (medial & lateral donor). Read More

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February 2021

High-resolution, non-contrast-enhanced magnetic resonance angiography of the wrist, hand and digital arteries using optimized implementation of Cartesian quiescent interval slice selective (QISS) at 1.5 T.

Magn Reson Imaging 2021 05 11;78:58-68. Epub 2021 Feb 11.

Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany.

Purpose: Non-contrast-enhanced (CE) magnetic resonance angiography (MRA) techniques are of considerable interest for diagnosing vascular diseases in the upper extremities owing to the possibility of repeated examinations, sufficient coverage of the measurement volume, and because possible side effects of administering iodine- or gadolinium-based contrast agents and radiation exposure can be avoided. The aim of this study was to investigate the feasibility of an optimized electrocardiogram (ECG) triggered Cartesian quiescent interval slice selective (QISS) technique for MRA of hand arteries.

Material And Methods: Both hands of 20 healthy volunteers (HVs) were examined using an optimized QISS-MRA pulse sequence at 1. Read More

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Rapid CT-based Estimation of Articular Cartilage Biomechanics in the Knee Joint Without Cartilage Segmentation.

Ann Biomed Eng 2020 Dec 11;48(12):2965-2975. Epub 2020 Nov 11.

Department of Applied Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland.

Knee osteoarthritis (OA) is a painful joint disease, causing disabilities in daily activities. However, there is no known cure for OA, and the best treatment strategy might be prevention. Finite element (FE) modeling has demonstrated potential for evaluating personalized risks for the progression of OA. Read More

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December 2020

Relaxation-compensated CEST (chemical exchange saturation transfer) imaging in breast cancer diagnostics at 7T.

Eur J Radiol 2020 Aug 24;129:109068. Epub 2020 May 24.

Division of Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. Electronic address:

Purpose: To investigate whether fat-corrected and relaxation-compensated amide proton transfer (APT) and guanidyl CEST-MRI enables the detection of signal intensity differences between breast tumors and normal-appearing fibroglandular tissue in patients with newly-diagnosed breast cancer.

Method: Ten patients with newly-diagnosed breast cancer and seven healthy volunteers were included in this prospective IRB-approved study. CEST-MRI was performed on a 7 T-whole-body scanner followed by a multi-Lorentzian fit analysis. Read More

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Contrast agent-free synthesis and segmentation of ischemic heart disease images using progressive sequential causal GANs.

Med Image Anal 2020 05 26;62:101668. Epub 2020 Feb 26.

Department of Medical Imaging, Western University, London ON, Canada. Electronic address:

The elimination of gadolinium contrast agent (CA) injections and manual segmentation are crucial for ischemic heart disease (IHD) diagnosis and treatment. In the clinic, CA-based late gadolinium enhancement (LGE) imaging and manual segmentation remain subject to concerns about potential toxicity, interobserver variability, and ineffectiveness. In this study, progressive sequential causal GANs (PSCGAN) are proposed. Read More

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Noninvasive monitoring of liver metastasis development via combined multispectral photoacoustic imaging and fluorescence diffuse optical tomography.

Int J Biol Sci 2020 12;16(9):1616-1628. Epub 2020 Mar 12.

OPTIMAL, Small animal Imaging Platform, F-38000 Grenoble, France.

molecular imaging in preclinical animal models is a tool of choice for understanding the pathophysiological mechanisms involved in cancer development and for conducting drug development research. Moreover, combining several imaging modalities can provide multifaceted, complementary and cross-validated information. Photoacoustic imaging (PAI) is a promising imaging modality that can reflect blood vasculature and tissue oxygenation as well as detect exogenous molecules, but one shortcoming of PAI is a lack of organic photoacoustic contrast agents capable of providing tumor contrast. Read More

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Magnetic resonance microscopy and correlative histopathology of the infarcted heart.

Sci Rep 2019 12 27;9(1):20017. Epub 2019 Dec 27.

Laboratory of Metabolomics, Institute of Health Research-INCLIVA, Valencia, Spain.

Delayed enhancement cardiovascular magnetic resonance (MR) is the gold-standard for non-invasive assessment after myocardial infarction (MI). MR microscopy (MRM) provides a level of detail comparable to the macro objective of light microscopy. We used MRM and correlative histopathology to identify infarct and remote tissue in contrast agent-free multi-sequence MRM in swine MI hearts. Read More

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December 2019

Gadolinium based contrast agent-free cardiac magnetic resonance imaging for the assessment of heart anatomy. A feasibility study.

Rev Esp Cardiol (Engl Ed) 2020 Jun 13;73(6):510-512. Epub 2019 Dec 13.

Cardiology/Electrophysiology Department, University Hospital Basel, University Basel, Basel, Switzerland; Cardiovascular Research Institute Basel, University Hospital Basel, University Basel, Basel, Switzerland.

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Super-resolution localization photoacoustic microscopy using intrinsic red blood cells as contrast absorbers.

Light Sci Appl 2019 20;8:103. Epub 2019 Nov 20.

Departments of Creative IT Engineering, Electrical Engineering, Mechanical Engineering, and Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673 Republic of Korea.

Photoacoustic microscopy (PAM) has become a premier microscopy tool that can provide the anatomical, functional, and molecular information of animals and humans in vivo. However, conventional PAM systems suffer from limited temporal and/or spatial resolution. Here, we present a fast PAM system and an agent-free localization method based on a stable and commercial galvanometer scanner with a custom-made scanning mirror (L-PAM-GS). Read More

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November 2019

Non-contrast enhanced diagnosis of acute myocarditis based on the 17-segment heart model using 2D-feature tracking magnetic resonance imaging.

Magn Reson Imaging 2020 01 9;65:155-165. Epub 2019 Nov 9.

Department for Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Campus Kiel, Germany.

Purpose: The aim of this study was to investigate the diagnostic value of myocardial deformation analysis based on the 17-segment heart model using non-contrast enhanced (CE) 2D tissue feature tracking (2D-FT) technique.

Material And Methods: Seventy patients with suspected myocarditis underwent a cardiovascular magnetic resonance (CMR) examination at 1.5 Tesla. Read More

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January 2020

Real-Time Transthoracic Vector Flow Imaging of the Heart in Pediatric Patients.

Prog Pediatr Cardiol 2019 Jun 5;53:28-36. Epub 2019 Mar 5.

University of Arkansas, Department of Biomedical Engineering, 790 W. Dickson St., Fayetteville, AR 72701, United States.

In children with congenital heart defects, Doppler ultrasound is the standard, bedside imaging modality. However, precise characterization of blood flow is challenging due to angle-dependent and one-dimensional velocity estimation. Contrast agent free Vector Flow Imaging is a new ultrasound technology that enables angle-independent visualization of the detailed flow field. Read More

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[Diffusion-weighted imaging-diagnostic supplement or alternative to contrast agents in early detection of malignancies?]

Radiologe 2019 Jun;59(6):517-522

Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Deutschland.

Medical research in the field of oncologic imaging diagnostics using magnetic resonance imaging increasingly includes diffusion-weighted imaging (DWI) sequences. The DWI sequences allow insights into different microstructural diffusion properties of water molecules in tissues depending on the sequence modification used and enable visual and quantitative analysis of the acquired imaging data. In DWI, the application of intravenous gadolinium-containing contrast agents is unnecessary and only the mobility of naturally occurring water molecules in tissues is quantified. Read More

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[Contrast-agent free imaging of the prostate : Ready for clinical practice?]

Radiologe 2019 Jun;59(6):503-509

Universitätsklinik für Radiologie und Nuklearmedizin, Medizinische Universität Wien & AKH-Wien, Währinger Gürtel 18-20, Ebene 7F, 1090, Wien, Österreich.

Background: Multiparametric MRI (mpMRI) is currently the most accurate imaging modality for detection and local staging of prostate cancer (PCa). Disadvantages of this modality are high costs, time consumption and the need for a contrast medium.

Aims: The aim of the work was to provide an overview of the current state of fast and contrast-free MRI imaging of the prostate. Read More

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[Contrast agent-free breast MRI : Advantages and potential disadvantages].

Radiologe 2019 Jun;59(6):510-516

Universitätsklinik für Radiologie und Nuklearmedizin, Allgemeine und Kinderradiologie, Allgemeines Krankenhaus, Medizinischen Universität Wien, Währinger Gürtel 18-20, 1090, Wien, Österreich.

Background: Contrast-enhanced breast magnetic resonance imaging (MRI) is the most sensitive method for detection of breast cancer. The further spread of breast MRI is limited by the complicated examination procedure and the need for intravenously administered contrast media.

Objectives: Can diffusion-weighted imaging (DWI) replace contrast-enhanced sequences to achieve an unenhanced breast MRI examination?

Materials And Methods: Narrative review and meta-analytic assessment of previously published studies. Read More

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Photoacoustic imaging for the evaluation of early tumor response to antivascular treatment.

Quant Imaging Med Surg 2019 Feb;9(2):160-170

Department of Medical Imaging, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, China.

Background: Photoacoustic imaging (PAI) provides real-time noninvasive and contrast agent-free monitoring of the concentrations of some endogenous compounds related to tumor vascularization and oxygenation. In this study, we used PAI to noninvasively evaluate tumor responses to antiangiogenic therapy.

Methods: In vivo studies were performed with the approval of our institutional animal ethics committee. Read More

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February 2019

Noninvasive Contrast-Free 3D Evaluation of Tumor Angiogenesis with Ultrasensitive Ultrasound Microvessel Imaging.

Sci Rep 2019 03 20;9(1):4907. Epub 2019 Mar 20.

Department of Radiology, Mayo Clinic College of Medicine and Science, Mayo Clinic, Rochester, MN, USA.

Ultrasound microvessel imaging (UMI), when applied with ultrafast planewave acquisitions, has demonstrated superior blood signal sensitivity in comparison to conventional Doppler imaging. Here we propose a high spatial resolution and ultra-sensitive UMI that is based on conventional line-by-line high-frequency ultrasound imagers and singular value decomposition (SVD) clutter filtering for the visualization and quantification of tumor microvasculature and perfusion. The technique was applied to a chicken embryo tumor model of renal cell carcinoma that was treated with two FDA-approved anti-angiogenic agents at clinically relevant dosages. Read More

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Imaging endogenous macrophage iron deposits reveals a metabolic biomarker of polarized tumor macrophage infiltration and response to CSF1R breast cancer immunotherapy.

Sci Rep 2019 01 29;9(1):857. Epub 2019 Jan 29.

Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.

Iron deposits are a phenotypic trait of tumor-associated macrophages (TAMs). Histological iron imaging and contrast-agent free magnetic resonance imaging (MRI) can detect these deposits, but their presence  in human cancer, and correlation with immunotherapeutic response is largely untested. Here, primarily using these iron imaging approaches, we evaluated the spatial distribution of polarized macrophage populations containing high endogenous levels of iron in preclinical murine models and human breast cancer, and used them as metabolic biomarkers to correlate TAM infiltration with response to immunotherapy in preclinical trials. Read More

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January 2019

Update on imaging in rheumatic diseases: cartilage.

Clin Exp Rheumatol 2018 Sep-Oct;36 Suppl 114(5):139-144. Epub 2018 Oct 1.

Department and Hiller-Research-Unit of Rheumatology, Heinrich-Heine-University Dusseldorf, Germany.

In recent years, the role of articular cartilage for understanding pathogenesis as well as for clinical research has become increasingly important. Whereas previously cartilage could only be assessed invasively, various imaging procedures are available for its evaluation now. Although still widely used, conventional radiography bears significant limitations since it assesses cartilage indirectly by joint space width. Read More

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January 2019

Cardiac Magnetic Resonance Imaging of the Myocardium in Chronic Kidney Disease.

Kidney Blood Press Res 2018 8;43(1):134-142. Epub 2018 Feb 8.

1st Department of Pediatrics, Semmelweis University, Budapest, Hungary.

Early stages of chronic kidney disease (CKD) are often underdiagnosed, while their deleterious effects on the cardiovascular (CV) system are already at work. Thus, the assessment of early CV damage is of crucial importance in preventing major CV events. Myocardial fibrosis is one of the major consequences of progressive CKD, as it may lead to reentry arrhythmias and long-term myocardial dysfunction predisposing to sudden death and/or congestive heart failure. Read More

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September 2018

Coronary magnetic resonance imaging after routine implantation of bioresorbable vascular scaffolds allows non-invasive evaluation of vascular patency.

PLoS One 2018 25;13(1):e0191413. Epub 2018 Jan 25.

Department of Cardiology and Angiology I, Heart Center Freiburg University, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Background: Evaluation of recurrent angina after percutaneous coronary interventions is challenging. Since bioresorbable vascular scaffolds (BVS) cause no artefacts in magnetic resonance imaging (MRI) due to their polylactate-based backbone, evaluation of vascular patency by MRI might allow for non-invasive assessment and triage of patients with suspected BVS failure.

Methods: Patients with polylactate-based ABSORB-BVS in proximal coronary segments were examined with 3 Tesla MRI directly (baseline) and one year after implantation. Read More

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Arterial Spin Labeling Cerebral Perfusion Magnetic Resonance Imaging in Migraine Aura: An Observational Study.

J Stroke Cerebrovasc Dis 2018 May 10;27(5):1262-1266. Epub 2018 Jan 10.

Department of Neurology, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany; Department of Neurology, Klinikum Kempten, Kempten, Germany.

Background: Changes in cerebral perfusion during migraine with aura (MA) have been assessed mainly using dynamic susceptibility contrast (DSC) magnetic resonance perfusion imaging. A contrast agent-free method to assess these changes would be desirable. We assessed changes in cerebral perfusion during MA using arterial spin labeling (ASL) perfusion magnetic resonance imaging. Read More

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Non-invasive quantitative imaging of hepatocellular carcinoma growth in mice by micro-CT using liver-targeted iodinated nano-emulsions.

Sci Rep 2017 10 24;7(1):13935. Epub 2017 Oct 24.

University of Strasbourg, Faculty of Pharmacy, 74 route du Rhin 67401 Illkirch-Graffenstaden Cedex, Strasbourg, France.

Hepatocellular carcinoma (HCC) is the only cancer for which non-invasive diagnosis is recognized by international guidelines. Contrast agent free ultrasound imaging, computed tomography (CT) and/or magnetic resonance imaging are techniques used for early detection and confirmation. Clinical evidence depicts that CT is 30% less precise as compared to MRI for detection of small tumors. Read More

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October 2017

Exploration of melanoma metastases in mice brains using endogenous contrast photoacoustic imaging.

Int J Pharm 2017 Nov 25;532(2):704-709. Epub 2017 Aug 25.

Institute for Advanced Biosciences, University of Grenoble Alpes, INSERM U1209, CNRS UMR5309, F-38000 Grenoble, France; OPTIMAL, Small Animal Imaging Platform, F-38000 Grenoble, France. Electronic address:

Photoacoustic imaging (PAI) provides real time non-invasive and contrast agent free monitoring of some endogenous compounds concentrations that provides improved insights into tissue vascularization and oxygenation which are particularly important during tumor progression. This study assessed the input of PAI for examination of melanoma brain metastases in an orthotopic mouse model and further focused on spatial analyses within the tumor tissue. Hemoglobin content appeared to be higher in tumors than in healthy brains. Read More

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November 2017

Maximum intensity breast diffusion MRI for BI-RADS 4 lesions detected on X-ray mammography.

Clin Radiol 2017 Oct 4;72(10):900.e1-900.e8. Epub 2017 Jul 4.

German Cancer Research Center (dkfz), Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.

Aim: To investigate an abbreviated, contrast-agent free diffusion-weighted (DW) breast magnetic resonance imaging (MRI) protocol that provides a single image for the radiologist to read in order to non-invasively examine Breast Imaging-Reporting and Data System (BI-RADS) 4 lesions detected using breast cancer screening X-ray mammography.

Materials And Methods: This retrospective evaluation within a institutional review board-approved, prospective study included 115 women (mean 57 years, range 50-69 years) with BI-RADS 4 findings on X-ray mammography and indication for biopsy over a period of 15 months. Full diagnostic breast MRI (FDP) was performed prior to biopsy (1. Read More

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October 2017

Novel MRI Technique Enables Non-Invasive Measurement of Atrial Wall Thickness.

IEEE Trans Med Imaging 2017 08 13;36(8):1607-1614. Epub 2017 Apr 13.

Knowledge of atrial wall thickness (AWT) has the potential to provide important information for patient stratification and the planning of interventions in atrial arrhythmias. To date, information about AWT has only been acquired in post-mortem or poor-contrast computed tomography (CT) studies, providing limited coverage and highly variable estimates of AWT. We present a novel contrast agent-free MRI sequence for imaging AWT and use it to create personalized AWT maps and a biatrial atlas. Read More

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A hyaluronic acid-based hydrogel enabling CD44-mediated chondrocyte binding and gapmer oligonucleotide release for modulation of gene expression in osteoarthritis.

J Control Release 2017 05 6;253:153-159. Epub 2017 Mar 6.

The Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark. Electronic address:

Hyaluronic acid (HA) is an attractive biomaterial for osteoarthritis (OA) treatment due to inherent functional and compatibility properties as an endogenous knee joint component. In this work, we describe a HA-based hydrogel with the dual functionality of increased CD44-dependent chondrocyte binding and controlled release of gapmer antisense oligonucleotides for unassisted cellular entry and subsequent gene silencing activity. A Schiff base-mediated gelation method was used to produce a panel of hydrogels varying in the aldehyde-modified HA (900kDa) to chitosan ratios (3:7, 5:5 and 7:3) for identifying designs displaying optimal engagement of OA patient-derived CD44-expressing chondrocytes. Read More

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Cardiac MR elastography for quantitative assessment of elevated myocardial stiffness in cardiac amyloidosis.

J Magn Reson Imaging 2017 11 25;46(5):1361-1367. Epub 2017 Feb 25.

Radiology, Mayo Clinic, Rochester, Minnesota, USA.

Purpose: To evaluate if cardiac magnetic resonance elastography (MRE) can measure increased stiffness in patients with cardiac amyloidosis. Myocardial tissue stiffness plays an important role in cardiac function. A noninvasive quantitative imaging technique capable of measuring myocardial stiffness could aid in disease diagnosis, therapy monitoring, and disease prognostic strategies. Read More

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November 2017

Prediction of malignancy by a radiomic signature from contrast agent-free diffusion MRI in suspicious breast lesions found on screening mammography.

J Magn Reson Imaging 2017 08 2;46(2):604-616. Epub 2017 Feb 2.

Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Purpose: To assess radiomics as a tool to determine how well lesions found suspicious on breast cancer screening X-ray mammography can be categorized into malignant and benign with unenhanced magnetic resonance (MR) mammography with diffusion-weighted imaging and T -weighted sequences.

Materials And Methods: From an asymptomatic screening cohort, 50 women with mammographically suspicious findings were examined with contrast-enhanced breast MRI (ceMRI) at 1.5T. Read More

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Effect of Nitroglycerin on the Performance of MR Coronary Angiography.

J Magn Reson Imaging 2017 05 12;45(5):1419-1428. Epub 2016 Oct 12.

Clinic Agatharied, Department of Cardiology, Academic Teaching Hospital, University of Munich, Hausham, Germany.

Purpose: To systematically investigate the effect of sublingual glyceryl trinitrate (nitroglycerin=nitro=glyceryl trinitrate=GTN=C H N O [NTG]) on the diagnostic performance of MR coronary artery imaging (MRCA) to detect relevant coronary artery disease (CAD).

Materials And Methods: Thirty-five healthy volunteers and 25 patients with suspected or proven CAD (all in sinus rhythm) underwent MRCA before and after NTG using a contrast-agent free, three-dimensional, navigator-based, steady state free precession acquisition (voxel size 1.0 × 0. Read More

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