Since the 1980s, gadolinium (Gd)-based contrast agents (GBCAs) have been routinely used in magnetic resonance imaging as stable chelates of the Gd3+ ion, without toxic effects. Generally, GBCAs are considered some of the safest contrast agents. However, it has been observed that they can accumulate in patient tissue, bone, and probably brain (causing nephrogenic systemic fibrosis in patients with kidney failure or insufficiency and disturbance of calcium homeostasis in the organism). The GBCAs are predominantly removed renally without metabolization. Subsequently, they do not undergo degradation processes in wastewater-treatment plants and are emitted into the aquatic ecosystem. Their occurrence was confirmed in surface waters (up to 1100 ng/L), sediments (up to 90.5 μg/g), and living organisms. Based on a literature review, there is a need to investigate the contamination of different ecosystems and to ascertain the environmental fate of Gd. Long-term ecotoxicological data, degradation, metabolism, bioaccumulation processes, and biochemical effects of the Gd complexes should be explored. These data can be used to assess detailed environmental risks because currently only hotspots with high levels of Gd can be marked as dangerous for aquatic environments according to environmental risk assessments. Environ Toxicol Chem 2018;37:1523-1534. © 2018 SETAC.

https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.4116

Gadolinium as a new emerging contaminant of aquatic environments.

The latest guidelines for the hospital care of patients affected by coronavirus disease 2019 (COVID-19)-related acute respiratory failure have moved towards the widely accepted use of noninvasive respiratory support (NIRS) as opposed to early intubation at the pandemic onset. The establishment of severe COVID-19 pneumonia goes through different pathophysiological phases that partially resemble typical acute respiratory distress syndrome (ARDS) and have been categorized into different clinical–radiological phenotypes. These can variably benefit on the application of external positive end-expiratory pressure (PEEP) during noninvasive mechanical ventilation, mainly due to variable levels of lung recruitment ability and lung compliance during different phases of the disease. A growing body of evidence suggests that intense respiratory effort producing excessive negative pleural pressure swings (Ppl) plays a critical role in the onset and progression of lung and diaphragm damage in patients treated with noninvasive respiratory support. Routine respiratory monitoring is mandatory to avoid the nasty continuation of NIRS in patients who are at higher risk for respiratory deterioration and could benefit from early initiation of invasive mechanical ventilation instead. Here we propose different monitoring methods both in the clinical and experimental settings adapted for this purpose, although further research is required to allow their extensive application in clinical practice. We reviewed the needs and available tools for clinical–physiological monitoring that aims at optimizing the ventilatory management of patients affected by acute respiratory distress syndrome due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection.

/pdf/different-methods-to-improve-the-monitoring-of-noninvasive-2uy20xe9.pdf

Different Methods to Improve the Monitoring of Noninvasive Respiratory Support of Patients with Severe Pneumonia/ARDS Due to COVID-19: An Update

X-ray iodinated contrast media have been shown to generate contrast in MR images when used with the chemical exchange saturation transfer (CEST) approach. The aim of this study is to compare contrast enhancement (CE) capabilities and perfusion estimates between radiographic molecules and a Gd-based contrast agent in two tumour murine models with different vascularization patterns. MRI-CEST and MRI-CE T1w images were acquired in murine TS/A and 4 T1 breast tumours upon sequential i.v. injection of iodinated contrast media (iodixanol, iohexol, and iopamidol) and of gadoteridol. The signal enhancements observed in the two acquisition modalities were evaluated using Pearson’s correlation, and the correspondence in the spatial distribution was assessed by a voxelwise comparison. A significant, positive correlation was observed between iodinated contrast media and gadoteridol for tumour contrast enhancement and perfusion values for both tumour models (r = 0.51-0.62). High spatial correlations were observed in perfusion maps between iodinated molecules and gadoteridol (r = 0.68-0.86). Tumour parametric maps derived by iodinated contrast media and gadoteridol showed high spatial similarities. A good to strong spatial correlation between tumour perfusion parameters derived from MRI-CEST and MRI-CE modalities indicates that the two procedures provide similar information. • Gd-based agents are the standard of reference for contrast-enhanced MRI.
 • Iodinated contrast media provides MRI-CEST contrast enhancement in animal tumour models.
 • Contrast enhancements were positively correlated between iodinated agents and gadoteridol.
 • Tumour perfusion map showed similar spatial distribution between iodinated agents and gadoteridol.
 • MRI-CEST with iodinated agents provide similar information to gadoteridol.

/pdf/mri-cest-assessment-of-tumour-perfusion-using-x-ray-3er80jrdlw.pdf

MRI-CEST assessment of tumour perfusion using X-ray iodinated agents: comparison with a conventional Gd-based agent

Liver metastases: Detection and staging.

EXCI-CEST: Exploiting pharmaceutical excipients as MRI-CEST contrast agents for tumor imaging.

Magnetic resonance plays a leading role in the management of oncology patients, providing superior contrast resolution and greater sensitivity compared with other techniques, which enables more accurate tumor identification, characterization and staging. Contrast agents are widely used in clinical magnetic resonance imaging; approximately 40–50% of clinical scans are contrast enhanced. Most contrast agents are based on the paramagnetic gadolinium ion Gd3+, which is chelated to avoid the toxic effects of free gadolinium. Multiple factors such as molecule structure, molecule concentration, dose, field strength and temperature determine the longitudinal and transverse relaxation rates (R1 and R2, respectively) and thus the T1- and T2-relaxivities of these chelates. These T1- and T2-relaxivities, together with their pharmacokinetic properties (i.e. distribution and concentration in the area of interest), determine the radiologic efficacy of the gadolinium-based contrast agents.

Use of contrast agents in oncological imaging: magnetic resonance imaging.

The role of imaging in COVID-19 pneumonia diagnosis and management: Main positions of the experts, key imaging features and open answers

A 74-year-old hypertensive woman presented with shortness of breath. There was no associated coughing, chest pain or fever. ECG identified atrial fibrillation with rapid ventricular response. A transoesophageal echocardiogram was scheduled to exclude thrombus before cardioversion (Figure 1A); however, an echogenic structure was seen (Figure 1B arrow, see online supplementary video 1) between the left atrium, the pulmonary artery and the aortic root.



Figure 1 
Two-dimensional transoesophageal echocardiography from mid-oesophageal view at 0° (A) and at 60° with anterior (B) flexion of the probe. AO, aorta; LA, left atrium; LAA, left atrial appendage; PA, pulmonary artery.



Which of the following is the most likely diagnosis? 

1. Aortic valve endocarditis with annular abscess

2. Left atrial appendage thrombus

3. Left atrial myxoma

4. Pulmonary embolism …

https://heart.bmj.com/content/heartjnl/102/9/693.full.pdf

An intriguing intracardiac mass in a woman with atrial fibrillation

Modern imaging of the pancreas has both a morphologic role, with an accurate delineation of the pancreatic tissue as well as of the pancreatic ducts and vessels, and a functional role, with the visualization of the pancreatic fluid cynetic and ductal dilation after secretin injection. The wide range of informations achievable with modern imaging techniques leads to a in depht knowledge of the different diagnostic value obtained by different imaging techniques. US is conventionally the first-line diagnostic tool to be used in patients with jaundice or abdominal pain, but with a low sensitivity and specificity, as the imaging feature of a hypoechoic mass cannot provide useful information to differentiate pancreatic cancer from massforming pancreatitis. Moreover, artifacts inside cavities can lead to difficulties in differentiating small cystic lesions from solid ones, or a false diagnosis of inhomogeneous content of cystic lesions. With Tissue Harmonic Imaging (THI) a reduction of artefacts inside cystic lesions can be obtained, allowing a better confidence in the nature of small hypoechoic lesions of the pancreas and a better fluid-solid differentiation. Acoustic Radiation Force Impulse (ARFI) technique allows to evaluate the mechanical strain properties of deep organs by means of a focused high intensity pulse to displace the target tissue. It has been utilized in the evaluation of acute pancreatitis, in the differentiation of benign and malignant focal pancreatic solid lesions, in the evaluation of the content of cystic pancreatic lesions [1-3]. Finally, CEUS has improved the characterization of pancreatic tumors, allowing a better differentiation between pancreatic carcinoma and mass-forming pancreatitis, adenocarcinoma and neuroendocrine tumor, serous and mucinous cystic pancreatic lesions [4]. MDCT is a robust technique to explore the pancreas, and it is the gold standard in the local staging of pancreatic carcinoma, thanks to its high spatial resolution, which allows a good depiction of the relationship of the tumor with the peri-pancreatic vessels. However, small iso-attenuating tumors can be hardly depicted with CT. New protocols with low-kV or dual energy technique improve the sensitivity of the MDCT, thus allowing the depiction of small tumors [5,6], especially with the use of new algorithms, which reduce the noise [7]. MRI it is used as a “problem solving” technique, when other imaging modalities are not able to resolve the clinical question, although in the evaluation of cystic tumor of the pancreas it is considered the gold standard, thanks to its high sensitivity to static fluids and different composition of fluids (mucin, blood, etc.). The most significant application of MR in the pancreas are:

/pdf/imaging-of-the-pancreas-state-of-the-art-4xpg50jeqd.pdf

Michele Fusaro

Papers

Use of contrast agents in oncological imaging: magnetic resonance imaging.

The role of imaging in COVID-19 pneumonia diagnosis and management: Main positions of the experts, key imaging features and open answers

An intriguing intracardiac mass in a woman with atrial fibrillation

Imaging of the pancreas: state of the art

Prevention of Coronary Artery Disease-Related Heart Failure: The Role of Computed Tomography Scan.