Search Results (82)

Four-dimensional (4D) flow MRI has shown promise for the assessment of aortic hemodynamics. However, data analysis traditionally requires manual and time-consuming human input at several stages. This limits reproducibility and affects analysis workflows, such that large-cohort 4D flow studies are lacking. Here, a fully automated artificial intelligence (AI) 4D flow analysis pipeline was developed and evaluated in a cohort of over 350 subjects. The 4D flow MRI analysis pipeline integrated a series of previously developed and validated deep learning networks, which replaced traditionally manual processing tasks (background-phase correction, noise masking, velocity anti-aliasing, aorta 3D segmentation). Hemodynamic parameters (global aortic pulse wave velocity (PWV), peak velocity, flow energetics) were automatically quantified. The pipeline was evaluated in a heterogeneous single-center cohort of 379 subjects (age = 43.5 ± 18.6 years, 118 female) who underwent 4D flow MRI of the thoracic aorta (n = 147 healthy controls, n = 147 patients with a bicuspid aortic valve [BAV], n = 10 with mechanical valve prostheses, n = 75 pediatric patients with hereditary aortic disease). Pipeline performance with BAV and control data was evaluated by comparing to manual analysis performed by two human observers. A fully automated 4D flow pipeline analysis was successfully performed in 365 of 379 patients (96%). Pipeline-based quantification of aortic hemodynamics was closely correlated with manual analysis results (peak velocity: r = 1.00, p < 0.001; PWV: r = 0.99, p < 0.001; flow energetics: r = 0.99, p < 0.001; overall r ≥ 0.99, p < 0.001). Bland–Altman analysis showed close agreement for all hemodynamic parameters (bias 1–3%, limits of agreement 6–22%). Notably, limits of agreement between different human observers’ quantifications were moderate (4–20%). In addition, the pipeline 4D flow analysis closely reproduced hemodynamic differences between age-matched adult BAV patients and controls (median peak velocity: 1.74 m/s [automated] or 1.76 m/s [manual] BAV vs. 1.31 [auto.] vs. 1.29 [manu.] controls, p < 0.005; PWV: 6.4–6.6 m/s all groups, any processing [no significant differences]; kinetic energy: 4.9 μJ [auto.] or 5.0 μJ [manu.] BAV vs. 3.1 μJ [both] control, p < 0.005). This study presents a framework for the complete automation of quantitative 4D flow MRI data processing with a failure rate of less than 5%, offering improved measurement reliability in quantitative 4D flow MRI. Future studies are warranted to reduced failure rates and evaluate pipeline performance across multiple centers. Full article

Stem cells therapies offer a promising approach in translational oncology, as well as in regenerative medicine due to the tropism of these cells to the damage site. To track the distribution of stem cells, the latter could be labeled by MRI-sensitive superparamagnetic (SPM) iron oxide nanoparticles. In the current study, magnetic properties of the magnetic nanoparticles (MNPs) incorporated into the bone marrow-derived fetal mesenchymal stem cells (FetMSCs) were evaluated employing nonlinear magnetic response measurements. Synthesized dextran-coated iron oxide nanoparticles were additionally characterized by X-ray diffraction, transmission electron microscopy, and dynamic light scattering. The MNP uptake by the FetMSCs 24 h following coincubation was studied by longitudinal nonlinear response to weak alternating magnetic field with registration of the second harmonic of magnetization. Subsequent data processing using a formalism based on the numerical solution of the Fokker–Planck kinetic equation allowed us to determine magnetic and dynamic parameters and the state of MNPs in the cells, as well as in the culture medium. It was found that MNPs formed aggregates in the culture medium; they were absorbed by the cells during coincubation. The aggregates exhibited SPM regime in the medium, and the parameters of the MNP aggregates remained virtually unchanged in the cells, indicating the preservation of the aggregation state of MNPs inside the cells. This implies also the preservation of the organic shell of the nanoparticles inside FetMSCs. The accumulation of MNPs by mesenchymal stem cells gradually increased with the concentration of MNPs. Thus, the study confirmed that the labeling of MSCs with MNPs is an effective method for subsequent cell tracking as incorporated nanoparticles retain their magnetic properties. Full article

Breast magnetic resonance imaging (MRI) is considered the most effective method for detecting breast cancer due to its high sensitivity. Yet multiple factors limit its widespread use, including high direct and indirect costs, a prolonged acquisition time with consequent patient discomfort, and a lack of trained radiologists. During the last decade, new strategies have been followed to increase the availability of breast MRI, including the omission of non-essential sequences to generate abbreviated MRI protocols (AB-MRIs) aimed at reducing the acquisition time with the potential of improving the patient’s experience and accommodating a higher number of MRI examinations per day. An alternative method is ultrafast MRI (UF-MRI), a novel technique that gathers kinetic data within the first minute after contrast injection, offering high temporal resolution. This enables the analysis of early contrast wash-in curves, showing promising outcomes. In this study, we reviewed the role of UF-MRI in breast imaging and detailed how the integration of this new approach with radiomics and mathematical models might further improve diagnostic accuracy and even have a prognostic role, a fundamental characteristic in the modern scenarios of personalized medicine. In addition, possible clinical applications and advantages of UF-MRI will be discussed. Full article

Background: While gallium-68 has traditionally dominated PET imaging in oncology, copper radionuclides have sparked interest for their potential applications in nuclear medicine and theranostics. Considering the advantageous physical decay properties of copper-61 compared to those of gallium-68, we describe a fully automated GMP-compliant synthesis process for ⁶¹Cu-based radiopharmaceuticals and demonstrate their in vivo application for targeting the overexpressed PSMA by PET/MR imaging. Methods: Copper-61 was obtained through the irradiation of natural zinc liquid targets in a biomedical cyclotron. [⁶¹Cu]Cu-DOTAGA-PSMA-I&T and [⁶¹Cu]Cu-NODAGA-PSMA-I&T were produced without manual intervention in two Synthera^® Extension modules. Radiochemical purity was analyzed by radio-HPLC and iTLC. Cellular uptake was evaluated in LNCaP and DU145 cells. In vivo PET/MRI was performed in control mice to evaluate the biodistribution of both radiopharmaceuticals, and in tumor-bearing mice to assess the targeting ability towards PSMA. Results: The fully automated process developed proved to be effective for the synthesis of ⁶¹Cu-based radiopharmaceuticals, with appropriate molar activities. The final products exhibited high radiochemical purity (>98%) and remained stable for up to 6 h after the EOS. A time-dependent increase in cellular uptake was observed in LNCaP cells, but not in DU145 cells. As opposed to [⁶¹Cu]Cu-NODAGA-PSMA-I&T, [⁶¹Cu]Cu-DOTAGA-PSMA-I&T exhibited poor kinetic stability in vivo. Subsequent PET/MR imaging with [⁶¹Cu]Cu-NODAGA-PSMA-I&T showed tumor uptake lasting up to 4 h post-injection, predominant renal clearance, and no detectable accumulation in non-targeted organs. Conclusions: These results demonstrate the feasibility of the implemented process, which yields adequate amounts of high-quality radiopharmaceuticals and can be adapted to any standard production facility. This streamlined approach enhances reproducibility and scalability, bringing copper-61 closer to widespread clinical use, to the detriment of the conventionally accepted gallium-68. Full article

Meticulous clinical examination is essential for spinal disorders to utilize the diagnostic methods and technologies that strongly support physicians and enhance clinical practice. A significant change in the approach to diagnosing spinal disorders has occurred in the last three decades, which has enhanced a more nuanced understanding of spine pathology. Traditional radiographic methods such as conventional and functional X-rays and CT scans are still the first line in the diagnosis of spinal disorders due to their low cost and accessibility. As more advanced imaging technologies become increasingly available worldwide, there is a constantly increasing trend in MRI scans for detecting spinal pathologies and making treatment decisions. Not only do MRI scans have superior diagnostic capabilities, but they also assist surgeons in performing meticulous preoperative planning, making them currently the most widely used diagnostic tool for spinal disorders. Positron Emission Tomography (PET) can help detect inflammatory lesions, infections, and tumors. Other advanced diagnostic tools such as CT/MRI fusion image, Functional Magnetic Resonance Imaging (fMRI), Upright and Kinetic MRI, magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI) could play an important role when it comes to detecting more special pathologies. However, some technical difficulties in the daily praxis and their high costs act as obstacles to their further spread. Integrating artificial intelligence and advancements in data analytics and virtual reality promises to enhance spinal procedures’ precision, safety, and efficacy. As these technologies continue to develop, they will play a critical role in transforming spinal surgery. This paradigm shift emphasizes the importance of continuous innovation and adaptability in improving the diagnosis and treatment of spinal disorders. Full article

Background: ATTRv and ATTRwt cardiac amyloidosis (CA) are underrecognized causes of heart failure with preserved left ventricular ejection fraction. The diagnosis of CA remains challenging due to low diagnostic suspicion and clinical overlap with more common diseases. The aim of this study was to use [^99mTc]-PYP SPECT-CT to perform a volumetric evaluation of bone scintigraphy to overcome the limitations of current practices. Methods: A monocentric prospective study was conducted to evaluate a lot of 22 patients with a mean age of 52.86 ± 13.80 years, diagnosed with hereditary cardiac transthyretin amyloidosis (ATTR). Results: Correlations between the quantitative SPECT-CT, clinical data, and morphological parameters were performed, demonstrating moderate to strong correlation of SUVmaxMyocardium/SUVmaxBone to both ECG low voltage and EchoGLS, SUVmaxMyocardium/SUVmaxLiver to myocardial gadolinium kinetics with T1 mapping MRI, diastolic disfunction, sensory–motor polyneuropathy, and EchoGLS, SUVmaxMyocardium/SUVmeanBone with diastolic disfunction and sensory–motor polyneuropathy, as well as SUVmaxMyocardium/SUVmaxSoft tissue to S II, respectively. Conclusions: The moderate to strong correlations among advanced quantitative SPECT-CT metrics and clinical and paraclinical data create the premises to use these parameters for early diagnosis of cardiac ATTR. Further multicentric studies in a larger patient population are needed to validate the newly identified quantitative SPECT-CT parameters. Full article

This research describes the development and thorough characterization of a novel, versatile, and biocompatible hybrid nanocarrier of the NO-releasing agent NOC-18, with a specific focus on optimizing the purification process. In this study, we focused on the sustained release of NO using biocompatible and diagnostic hybrid magnetic nanoparticles (hMNPs) containing cerium-doped maghemite (CM) NPs, embedded within human serum albumin (HSA) protein. A comprehensive study was conducted using electron paramagnetic resonance (EPR) alongside the Griess assay to evaluate NO release from the chosen NO donor, NOC-18, and to assess the limitations of the molecule under various reaction conditions, identifying the optimal conditions for binding NOC-18 with minimal NO loss. Two types of particles were designed: In-hMNPs, where NOC-18 is encapsulated within the particles, and Out-hMNPs, where NOC-18 is attached onto the surface. Our results demonstrated that In-hMNPs provided a sustained and prolonged release of NO (half-life, 50 h) compared to the rapid release for the Out-hMNPs, likely due to the strong bonds formed with cerium, which helped to stabilize the NO molecules. These results represent a promising approach to designing a dual-function agent that combines contrast properties for tumor MRI with the possibility of increasing the permeability of tumor vasculature. The employment of this dual-function agent in combination with nanotherapeutics could improve the latter’s efficacy by facilitating their access to the tumor. Full article

Objectives: To evaluate the effectiveness of breast MRI, including diffusion-weighted imaging (DWI), in detecting residual lesions in patients with malignancy after excisional biopsy. Methods: From January 2018 to December 2023, 3T breast MRI was performed to assess lesion morphology, residual size, and enhancement kinetics. The apparent diffusion coefficient (ADC) values were measured, and the diagnostic outcomes of CE-MRI, CE-MRI with DWI, mammography (MG), and ultrasound (US) were compared with clinical and histopathological data. Results: A total of 152 lesions were analyzed, with 36.2% showing residual malignancy. Both CE-MRI and CE-MRI with DWI effectively identified residual lesions, with significant differences in morphology, size, kinetic patterns, and ADC values (all p < 0.001). CE-MRI with DWI showed a sensitivity of 90.9% and an NPV of 93.6%, compared with 89.1% sensitivity and 92.2% NPV for CE-MRI alone. Sensitivities for MG and US were 57.1% and 38.7%, with NPVs of 64.7% and 59.6%, respectively. Diagnostic accuracy was highest for CE-MRI with DWI (80.9%), followed by CE-MRI (79.0%), MG (60.3%), and US (59.7%). The AUC for CE-MRI with DWI (0.831) was slightly higher than CE-MRI alone (0.811), though not significant (p = 0.095). AUCs for MG and US were lower at 0.623 and 0.563, with no significant difference between MG and US (p = 0.234). Conclusions: CE-MRI with DWI and CE-MRI alone were comparable and demonstrated excellent performance in discriminating between women with and without residual disease. Integrating CE-MRI with DWI could become a standard protocol for patients with suspected residual malignancy after excisional biopsy. Full article

Intra-cardiac kinetic energy (KE) and ventricular flow analysis (VFA), as derived from 4D-flow MRI, can be used to understand the physiological burden placed on the left ventricle (LV) due to bicuspid aortic valve (BAV). Our hypothesis was that the KE of each VFA component would impact the surgical referral outcome depending on LV function decrement, BAV phenotype, and aortic dilation severity. A total of 11 healthy controls and 49 BAV patients were recruited. All subjects underwent cardiac magnetic resonance imaging (MRI) examination. The LV mass was inferior in the controls than in the BAV patients (90 ± 26 g vs. 45 ± 17 g, p = 0.025), as well as the inferior ascending aorta diameter indexed (15.8 ± 2.5 mm/m² vs. 19.3 ± 3.5 mm/m², p = 0.005). The VFA KE was higher in the BAV group; significant increments were found for the maximum KE and mean KE in the VFA components (p < 0.05). A total of 14 BAV subjects underwent surgery after the scans. When comparing BAV nonsurgery vs. surgery-referred cohorts, the maximum KE and mean KE were elevated (p < 0.05). The maximum and mean KE were also associated with surgical referral (r = 0.438, p = 0.002 and r = 0.371, p = 0.009, respectively). In conclusion, the KE from VFA components significantly increased in BAV patients, including in BAV patients undergoing surgery. Full article

Background: Accurate measurements of flow and ventricular volume and function are critical for clinical decision-making in cardiovascular medicine. Cardiac magnetic resonance (CMR) is the current gold standard for ventricular functional evaluation but is relatively expensive and time-consuming, thus limiting the scale of clinical applications. New volumetric acquisition techniques, such as four-dimensional flow (4D-flow) and three-dimensional volumetric cine (3D-cine) MRI, could potentially reduce acquisition time without loss in accuracy; however, this has not been formally tested on a large scale. Methods: 4DCarE (4D-flow MRI for cardiovascular evaluation) is a prospective, multi-centre study designed to test the non-inferiority of a compressed 20 min exam based on volumetric CMR compared with a conventional CMR exam (45–60 min). The compressed exam utilises 4D-flow together with a single breath-hold 3D-cine to provide a rapid, accurate quantitative assessment of the whole heart function. Outcome measures are (i) flow and chamber volume measurements and (ii) overall functional evaluation. Secondary analyses will explore clinical applications of 4D-flow-derived parameters, including wall shear stress, flow kinetic energy quantification, and vortex analysis in large-scale cohorts. A target of 1200 participants will enter the study across three sites. The analysis will be performed at a single core laboratory site. Pilot Results: We present a pilot analysis of 196 participants comparing flow measurements obtained by 4D-flow and conventional 2D phase contrast, which demonstrated moderate–good consistency in ascending aorta and main pulmonary artery flow measurements between the two techniques. Four-dimensional flow underestimated the flow compared with 2D-PC, by approximately 3 mL/beat in both vessels. Conclusions: We present the study protocol of a prospective non-inferiority study of a rapid cardiac MRI exam compared with conventional CMR. The pilot analysis supports the continuation of the study. Study Registration: This study is registered with the Australia and New Zealand Clinical Trials Registry (Registry number ACTRN12622000047796, Universal Trial Number: U1111-1270-6509, registered 17 January 2022—Retrospectively registered). Full article

Evaluating intratumor heterogeneity with image texture analysis offers a more sophisticated understanding of sarcoma response to treatment. We examined the effects of inductive moderate hyperthermia (IMH) on sarcoma-45 growth and intratumor heterogeneity across tissue, cellular and molecular levels using magnetic resonance imaging (MRI), ultrasound and histology image analysis. IMH (42 MHz, 20 W) inhibited sarcoma-45 growth kinetics by 34% compared to the untreated control group. T₂-weighted MRI brightness was increased by 42%, reflecting more extensive tumor necrosis, while Young’s modulus increased by 37% due to more pronounced connective tissue replacement in response to IMH. Whereas calculations of Moran’s spatial autocorrelation index revealed distinctions in heterogeneity between tumor core, periphery and capsule regions of interest (ROIs) on MRI, ultrasound and histological examination in the untreated tumor-bearing animals, there was no significant difference between core and periphery after IMH. Exposure to IMH increased overall tumor ROI heterogeneity by 22% on MRI but reduced heterogeneity in the core and periphery on ultrasound and histology images. Ki-67 protein distribution was 25% less heterogeneous on the tumor periphery after IMH. Therefore, this study provides a quantitative characterization of IMH effects on different manifestations of intratumor sarcoma-45 heterogeneity using experimental imaging data. Full article

AAZTA (6-amino-6-methylperhydro-1,4-diazepinetetraacetic acid) is a mesocyclic chelating agent forming stable complexes with several metal ions. Over the past 20 years since its inception, AAZTA and its bifunctional derivatives have gained a growing role in several applications ranging from MRI contrast agents to diagnostics and nuclear medicine. The recent market restrictions applied to nitroethane preclude the easy preparation of AAZTA, prompting the search for a suitable alternative. In this work, we report the synthesis of two structural analogs (AAZTA-Bn and AAZTA-Et) from commercially available chemicals and the thermodynamic and kinetic study of their complexing ability towards selected metal ions. A comparison of the complexing properties of AAZTA-Bn and AAZTA-Et with the former AAZTA allows us to identify the possible heir of this efficient chelating agent. Full article

Background: Cardiac magnetic resonance (cMRI) is often used to diagnose acute myocarditis (AM). It is also performed after 6 months to monitor myocardial involvement. However, the clinical and predictive relevance of the 6-month cMRI is uncertain. Objective: We used cMRI to assess the morphology and heart function of patients with AM, the correlation between left ventricular remodeling and biomarkers of heart dysfunction and myocardial fibrosis, and the involvement of myocardial fibrosis initially and 6 months after the acute episode. Materials and methods: We conducted a prospective study of 90 patients with the clinical suspicion of AM, where cMRI was performed within the first week after symptom onset and repeated after 6 months. Results: Non-ischemic late gadolinium enhancement (LGE) was present in 88 (97.7%) patients and mainly involved the septum and inferior wall. cMRI at 6 months was associated with significantly reduced abnormalities of segmental kinetics (p < 0.001), myocardial edema (p < 0.001), presence of LGE (p < 0.05) and LGE mass (p < 0.01), native T1 mapping (p < 0.001), and presence of pericardial collection (p ≤ 0.001). At 6 months, signs of myocardial edema appeared in 34.4% of patients, and a complete cure (absence of edema and LGE) was found in 8.8% of patients. LGE disappeared in 15.2% of patients, and the mean number of myocardial segments involved decreased from 46% to 30%, remaining unchanged in 13% of patients. Patients with LGE without edema had a more severe prognostic condition than those with persistent edema. Patients with increased LGE extension on the control cMRI had a worse prognosis than those with modified or low LGE. The most significant independent predictive parameters for major cardiovascular events (MACEs) were LGE mass (adjusted OR = 1.27 [1.11–1.99], p < 0.001), myocardial edema (OR = 1.70 [1.14–209.3], p < 0.001), and prolonged native T1 (OR = 0.97 [0.88–3.06], p < 0.001). The mid-wall model of LGE and the presence of edema-free LGE were MACE-independent predictors. Conclusions: LGE, myocardial edema, and prolonged native T1 were predictors of MACEs. LGE does not necessarily mean constituted fibrosis in the presence of edema and may disappear over time. LGE without edema could represent fibrosis, whereas the persistence of edema represents active inflammation and could be associated with the residual chance of complete recovery. cMRI should be performed in all patients with AM at 6 months to evaluate progress and prognosis. Full article

The glymphatic system has recently been shown to be important in neurological diseases, including diabetes. However, little is known about how the progressive onset of diabetes affects the glymphatic system. The aim of this study is to investigate the glymphatic system response to the progressive onset of diabetes in a rat model of type 2 diabetic mellitus. Male Wistar rats (n = 45) with and without diabetes were evaluated using MRI glymphatic tracer kinetics, functional tests, and brain tissue immunohistochemistry. Our data demonstrated that the contrast agent clearance impairment gradually progressed with the diabetic duration. The MRI data showed that an impairment in contrast clearance occurred prior to the cognitive deficits detected using functional tests and permitted the detection of an early DM stage compared to the immuno-histopathology and cognitive tests. Additionally, the quantitative MRI markers of brain waste clearance demonstrated region-dependent sensitivity in glymphatic impairment. The improved sensitivity of MRI markers in the olfactory bulb and the whole brain at an early DM stage may be attributed to the important role of the olfactory bulb in the parenchymal efflux pathway. MRI can provide sensitive quantitative markers of glymphatic impairment during the progression of DM and can be used as a valuable tool for the early diagnosis of DM with a potential for clinical application. Full article

A total of 457 patients, including 241 HR+/HER2− patients, 134 HER2+ patients, and 82 TN patients, were studied. The percentage of TILs in the stroma adjacent to the tumor cells was assessed using a 10% cutoff. The low TIL percentages were 82% in the HR+ patients, 63% in the HER2+ patients, and 56% in the TN patients (p < 0.001). MRI features such as morphology as mass or non-mass enhancement (NME), shape, margin, internal enhancement, presence of peritumoral edema, and the DCE kinetic pattern were assessed. Tumor sizes were smaller in the HR+/HER2− group (p < 0.001); HER2+ was more likely to present as NME (p = 0.031); homogeneous enhancement was mostly seen in HR+ (p < 0.001); and the peritumoral edema was present in 45% HR+, 71% HER2+, and 80% TN (p < 0.001). In each subtype, the MR features between the high- vs. low-TIL groups were compared. In HR+/HER2−, peritumoral edema was more likely to be present in those with high TILs (70%) than in those with low TILs (40%, p < 0.001). In TN, those with high TILs were more likely to present a regular shape (33%) than those with low TILs (13%, p = 0.029) and more likely to present the circumscribed margin (19%) than those with low TILs (2%, p = 0.009). Full article