The protein and contrast agent-specific influence of pathological plasma-protein concentration levels on contrast-enhanced magnetic resonance imaging

OBJECTIVE: The objective of this study was to measure the protein-specific response of r1 and r2 relaxivities of commercially available gadolinium-based magnetic resonance imaging contrast agents to variation of plasma-protein concentrations. MATERIALS AND METHODS: In this in vitro study, contrast agent (gadofosveset trisodium, gadoxetate disodium, gadobutrol, and gadoterate meglumine) dilution series (0-2.5 mmol Gd/L) were prepared with plasma-protein (human serum albumin [HSA] and immunoglobulin G [IgG]) concentrations at physiological (42 and 10 g/L HSA and IgG, respectively, Normal) and at 3 pathological levels with HSA/IgG concentrations of 10/10 (solution Alb low), 42/50 (IgG mild), and 42/70 (IgG severe) g/L. Contrast-agent molar relaxivities and relaxivity-enhancing protein-contrast-agent interaction coefficients were determined on the basis of inversion-recovery and spin-echo data acquired at 1.5 and 3.0 T at 37°C. Protein-induced magnetic resonance imaging signal changes were calculated. RESULTS: The effective r1 and r2 molar relaxivities consistently increased with albumin and IgG concentrations. At 1.5 T, the r1 values increased by 10.2 (gadofosveset), 4.3 (gadoxetate), 1.3 (gadobutrol), and 1.1 L s mmol (gadoterate), respectively, from the Alb low to the IgG severe solution. At 3.0 T, the r1 values increased by 2.9 (gadofosveset), 2.3 (gadoxetate), 0.7 (gadobutrol), and 0.9 (gadoterate) L s mmol, respectively. An excess of IgG most strongly increased the r1 of gadoxetate (+40 and +19% at 1.5 and 3.0 T, respectively, from Normal to IgG severe). An albumin deficiency most strongly decreased the r1 of gadofosveset (-44% and -20% at 1.5 and 3.0 T, respectively, from Normal to Alb low). The modeling confirmed a strong gadofosveset r1 enhancement by albumin and suggested stronger IgG than albumin effects on the apparent molar relaxivity of the other agents per protein mass concentration at 1.5 T. CONCLUSIONS: Pathological deviations from normal plasma-protein concentrations in aqueous solutions result in changes of effective r1 and r2 contrast-agent relaxivities and projected signal enhancements that depend on the contrast agent, the blood-serum protein profile, and the field strength

Contrast-Enhanced Clinical Magnetic Resonance Imaging

In Contrast-Enhanced Clinical Magnetic Resonance Imaging, Val M. Runge and other leading experts present an overview of the basic principles regarding MR contrast media, a review of clinical applications in the head, spine, and body, and a look at future developments. Their focus is on clinical applications, with extensive illustrations to demonstrate the use of MR in each anatomic area and to aid in film interpretation. Val M. Runge is Rosenbaum Professor of Radiology and director of the Magnetic Resonance Imaging and Spectroscopy Center at the University of Kentucky Chandler Medical Center.https://uknowledge.uky.edu/upk_medicine_and_health_sciences/1006/thumbnail.jp

Scientific Advances and Technical Innovations in Musculoskeletal Radiology.

Decades of technical innovations have propelled musculoskeletal radiology through an astonishing evolution. New artificial intelligence and deep learning methods capitalize on many past innovations in magnetic resonance imaging (MRI) to reach unprecedented speed, image quality, and new contrasts. Similarly exciting developments in computed tomography (CT) include clinically applicable molecular specificity and substantially improved spatial resolution of musculoskeletal structures and diseases. This special issue of Investigative Radiology comprises a collection of expert summaries and reviews on the most impactful innovations and cutting-edge topics in musculoskeletal radiology, including radiomics and deep learning methods for musculoskeletal disease detection, high-resolution MR neurography, deep learning-driven ultra-fast musculoskeletal MRI, MRI-based synthetic CT, quantitative MRI, modern low-field MRI, 7.0 T MRI, dual-energy CT, cone beam CT, kinematic CT, and synthetic contrast generation in musculoskeletal MRI

Advocating the Development of Next-Generation, Advanced-Design Low-Field Magnetic Resonance Systems.

New next-generation low-field magnetic resonance imaging systems (operating in the range of 0.5 T) hold great potential for increasing access to clinical diagnosis and needed health care both in developed countries and worldwide. The relevant history concerning the choice of field strength, which resulted in 1.5 T still dominating today the number of installed systems, is considered, together with design advances possible because of interval developments, since low field was considered for clinical use in the 1980s, and current research. The potential impact of low-cost, advanced-generation low-field magnetic resonance imaging systems, properly designed, is high in terms of further dissemination of health care-across the gamut from industrial to developing countries-regardless of disease entity and anatomic region of involvement, with major niche applications likely as well

A New Era in Magnetic Resonance Contrast Media.

Next-generation gadolinium-based contrast agents (GBCAs), including both high relaxivity agents and targeted agents, and manganese-based agents with a high probably of commercial success are discussed in some depth. It is highly likely that gadopiclenol and gadoquatrane, both next-generation high relaxivity gadolinium-based compounds, will come in time to replace the current macrocyclic gadolinium chelates, despite the wide acceptance, very high safety profile, and high stability of the latter group. Current research has also made possible the development of 2 new targeted gadolinium chelates, which look very promising, with the potential to improve cancer detection (for both MT218 and ProCA32.collagen) as well as diseases of collagen (for the latter agent). Further work with manganese-based compounds, a topic left fallow for more than 20 years, has also now produced 2 agents with high potential for clinical use, one (manganese chloride tetrahydrate, administered orally) developed primarily for imaging of the liver and the other (Mn-PyC3A, administered intravenously) as a gadolinium-free replacement for the GBCAs. New detail has recently emerged regarding specific circumscribed subregions of the brain with specialized cytoarchitecture and functions in which high gadolinium concentrations are seen following injection of the linear agent gadodiamide. These findings pave the way for tailored functional neurological testing, specifically in patients at potential risk due to the continued wide use in many countries across the world of the linear GBCAs. The impact of artificial intelligence is also critically discussed, with its most likely applications being dose reduction and new clinical indications

The Clinical Utility of Magnetic Resonance Imaging According to Field Strength, Specifically Addressing the Breadth of Current State-of-the-Art Systems, Which Include 0.55 T, 1.5 T, 3 T, and 7 T.

ABSTRACT This review provides a balanced perspective regarding the clinical utility of magnetic resonance systems across the range of field strengths for which current state-of-the-art units exist (0.55 T, 1.5 T, 3 T, and 7 T). Guidance regarding this issue is critical to appropriate purchasing, usage, and further dissemination of this important imaging modality, both in the industrial world and in developing nations. The review serves to provide an important update, although to a large extent this information has never previously been openly presented. In that sense, it serves also as a position paper, with statements and recommendations as appropriate