Tuning of Hydrogel Architectures by Ionotropic Gelation in Microfluidics: Beyond Batch Processing to Multimodal Diagnostics

Microfluidics is emerging as a promising tool to control physicochemical properties of nanoparticles and to accelerate clinical translation. Indeed, microfluidic-based techniques offer more advantages in nanomedicine over batch processes, allowing fine-tuning of process parameters. In particular, the use of microfluidics to produce nanoparticles has paved the way for the development of nano-scaled structures for improved detection and treatment of several diseases. Here, ionotropic gelation is implemented in a custom-designed microfluidic chip to produce different nanoarchitectures based on chitosan-hyaluronic acid polymers. The selected biomaterials provide biocompatibility, biodegradability and non-toxic properties to the formulation, making it promising for nanomedicine applications. Furthermore, results show that morphological structures can be tuned through microfluidics by controlling the flow rates. Aside from the nanostructures, the ability to encapsulate gadolinium contrast agent for magnetic resonance imaging and a dye for optical imaging is demonstrated. In conclusion, the polymer nanoparticles here designed revealed the dual capability of enhancing the relaxometric properties of gadolinium by attaining Hydrodenticity and serving as a promising nanocarrier for multimodal imaging applications.

Enhancement of subarachnoid space during magnetic resonance imaging of endolymphatic hydrops: a case report

Enhancement of the subarachnoid space after intravenous administration of gadolinium contrast agent is not common. Enhancement usually occurs in pathological conditions that increase the permeability of the blood–cerebrospinal fluid barrier, most notably in meningitis. We herein describe possible subarachnoid enhancement in patients with no apparent effect on the meninges. These patients had clinical signs of Meniere’s disease and underwent specific magnetic resonance imaging of the inner ear to possibly visualize endolymphatic hydrops. The endolymphatic space can be noninvasively imaged by intravenous administration of contrast agent, usually at a double dose, 4 hours before the scanning process. During this time, the contrast agent penetrates not only the perilymph but also the subarachnoid space, where the highest concentration occurs after 4 hours according to some studies.

Introduction of Cardiac Magnetic Resonance Imaging in Kosovo: First Fifty Consecutive Patients Registry Report

BACKGROUND: Cardiac magnetic resonance (CMR) as advanced diagnostic tool for the heart has been introduced in our institution since September 2019. AIM: We report on the first fifty consecutive patients using this imaging modality. METHODS AND MATERIALS: Strict protocol for CMR procedure, imaging quality assessment, contraindications, and informed consent were established. Patients selected for CMR were enrolled in a prospective registry. Visualizing the heart chambers, heart muscle and heart valves, resulted in acquiring complex imaging of the heart structure and function. When applicable, patients received gadolinium contrast agent for Late Gadolinium Enhancement (LGE). Adenosine was used for stress induced myocardial perfusion study. In this study, we report on the initial CMR procedures in the first 15 months. RESULTS: The age of the patients ranges from 17 to 82 and the number of male and female patients was well balanced. No absolute contraindications were met in any patient. Relative contraindications were noted but did not prevent from performing the scan. Different cardiac pathologies were encountered in the examined patients. Most common was the ischemic heart disease – 19 (38%). We had 15 (30%) out of 46 (92%) CMR procedures with LGE showing fibrotic scaring. Quality image assessment was scaled from poor to excellent. Most of the assessments were graded very good and good (46% and 48%), no poor, and very poor noted. CONCLUSION: CMR has been successfully introduced in Kosovo as excellent imaging tool for diagnosing and characterizing a nearly exhaustive spectrum of heart diseases.

Motion-corrected free-breathing late gadolinium enhancement combined with a gadolinium contrast agent with a high relaxation rate: an optimized cardiovascular magnetic resonance examination protocol

Objective This prospective study investigated the feasibility of an optimized cardiovascular magnetic resonance (CMR) examination protocol using the motion-corrected (MOCO), balanced steady-state free precession (bSSFP), phase-sensitive inversion recovery (PSIR) sequence combined with a gadolinium contrast agent with a high relaxation rate in patients who cannot hold their breath. Methods Fifty-one patients with heart disease underwent CMR examinations twice and these were performed with different late gadolinium enhancement (LGE) imaging sequences (fast low-angle shot [FLASH] sequence vs. MOCO sequence) and different gadolinium contrast agents (gadopentetate dimeglumine vs. gadobenate dimeglumine) with a 48-hour interval. LGE image quality, total time spent in the whole study, and time taken to perform LGE imaging were compared for the two CMR examinations. Results LGE images with the MOCO bSSFP PSIR sequence showed significantly higher image quality compared with those with the segmented FLASH PSIR sequence. There was a significant difference between the total scan time for the two examinations and different LGE sequences. Conclusions The MOCO bSSFP PSIR sequence effectively improves the quality of LGE images. Changing the CMR scanning protocol by combining the MOCO bSSFP PSIR sequence with a gadolinium contrast agent with a high relaxation rate effectively shortens the scan time. Clinical trial registration number: ChiCTR-ROC-17013978.

Computer Simulation of the Effects of Contrast Protocols on Aortic Signal Intensity on Magnetic Resonance Angiograms

Background: While iodine-enhanced computed tomography has been studied, detailed information on gadolinium-enhanced magnetic resonance imaging has not been reported. Objective: The purpose of this study was to evaluate the effect of various gadolinium contrast agent (Gd-CA) factors on enhancement on aortic magnetic resonance angiography (MRA) using computer simulation. Methods: We developed a computer simulation software combines pharmacokinetic models and tables that converts the blood concentration of particular Gd-CAs into the signal intensity (SI). We simulate aortic time-intensity curves (TIC) on MRA study. We compared the effect of the Gd-CA volume, injection rate, and different Gd-CAs on the TIC. Results: An increase in the Gd-CA volume from 14.0 to 28.0 ml increased maximal aortic intensity 1.11 times. Changing the injection rate from 1.0 to 2.8 ml/s increased it 1.10 times. Compared with gadoteridol, the maximal signal intensity (SI) of gadoterate-meglumine and gadobutrol was 1.03 and 1.01 times, respectively that of gadoteridol. Conclusion: In our computer-simulated MRA study, different Gd-CA factors resulted in no significant difference in the maximal aortic SI

A New Class of Smart Gadolinium Contrast Agent for Tissue pH Probing Using Magnetic Resonance Imaging

Detecting tissue pH in vivo is extremely vital for medical diagnosis and formulation of treatment decisions. To this end, many investigations have been carried out to develop an accurate and efficient method of in vivo pH measurement. Most of the techniques developed so far suffer from inadequate accuracy, due to poor sensitivity at low concentration of the target or nonspecific interactions within the tissue matrix. To overcome these issues, we describe herein the development of a simple, yet reliable, way to estimate pH with high precision using a Gd(III)-DOTA-silyl-based acid-labile group as a pH-sensitive contrast agent with Magnetic Resonance Imaging (MRI). With this method, a change in T 1 weighted image intensity of the newly developed pH-sensitive contrast is directly linked to the proton concentration in the media. As a result, we were able estimate the pH of the target with 95% reliability.

An advanced micelle-based biodegradable HPMA polymer-gadolinium contrast agent for MR imaging of murine vasculatures and tumors

A biodegradable HPMA polymeric micelle-based MR contrast agent containing gadolinium (Gd3+) for imaging murine vascular structures and tumors.