Quantitative MRI for Monitoring Metabolic Dysfunction-Associated Steatotic Liver Disease: A Test-Retest Repeatability Study.

BACKGROUND: Quantitative magnetic resonance imaging metrics iron-corrected T1 (cT1) and liver fat from proton density fat-fraction (PDFF) are both commonly used as noninvasive biomarkers for metabolic dysfunction-associated steatohepatitis (MASH); however, their repeatability in this population has rarely been characterized. PURPOSE: To quantify the variability of cT1 and liver fat fraction from PDFF in patients with biopsy-confirmed metabolic dysfunction-associated steatotic liver disease (MASLD) and MASH. STUDY TYPE: Prospective, single center. POPULATION: Twenty-one participants (female = 11, mean age 53 ± 24 years) with biopsy-confirmed MASLD, including 6 with MASH and fibrosis ≥2. FIELD STRENGTH/SEQUENCE: 3 T; T1 and T2* mapping for the generation of cT1 (shMOLLI: CardioMaps and 2D MDE, T1map-FIESTA and LMS MOST: StarMap, 2D Multi-Echo FSPGR) and magnitude-only PDFF sequence for liver fat quantification (LMS IDEAL: StarMap, 2D Multi-Echo FSPGR). ASSESSMENT: T1 mapping and PDFF scans were performed twice on the same day for all participants (N = 21), with an additional scan 2-4 weeks later for MASH patients with fibrosis ≥2 (N = 6). Whole liver segmentation masks were generated semi-automatically and average pixel counts within these masks were used for the calculation of cT1 and liver fat fraction. STATISTICAL TESTS: Bland-Altman analysis for repeatability coefficient (RC) and 95% limits of agreement (LOA) and intraclass correlation coefficient (ICC). RESULTS: Same-day RC was 32.1 msec (95% LOA: -36.6 to 24.2 msec) for cT1 and 0.6% (95% LOA: -0.5% to 0.7%) for liver fat fraction; the ICCs were 0.98 (0.96-0.99) and 1.0, respectively. Short-term RC was 65.2 msec (95% LOA: -63.8 to 76.5 msec) for cT1 and 2.6% (95% LOA: -2.8% to 3.1%) for liver fat fraction. DATA CONCLUSION: In participants with MASLD and MASH, cT1 and liver fat fraction measurements show excellent test-retest repeatability, supporting their use in monitoring MASLD and MASH. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Decreases in cT1 and liver fat content reflect treatment-induced histological improvements in MASH.

BACKGROUND & AIMS: MRI biomarkers of liver disease are robust and reproducible alternatives to liver biopsy. Emerging data suggest that absolute reduction in iron corrected T1 (cT1) of ≥ 80 ms and relative reduction in liver fat content of 30% reflect histological improvement. We aimed to validate the associations of changes to these noninvasive biomarkers with histological improvement, specifically the resolution of steatohepatitis. METHODS: A retrospective analysis of participants from three interventional clinical trials who underwent multiparametric MRI to measure liver cT1 and liver fat content (LFC) (LiverMultiScan) alongside biopsies at baseline and end of study. Responders were defined as those achieving resolution of steatohepatitis with no worsening in fibrosis. Differences in the magnitude of change in cT1 and LFC between responders and non-responders was assessed. RESULTS: Individual patient data from 150 participants were included. There was a significant decrease in liver cT1 (-119 ms vs. -49 ms) and liver fat content (-65% vs. -29%) in responders compared to non-responders (P < .001) respectively. The diagnostic accuracy to identify responders was 0.72 (AUC) for both. The Youden's index for cT1 to separate responders from non-responders was -82 ms and for liver fat was a 58% relative reduction. Those achieving a ≥ 80 ms reduction in cT1 were 5-times more likely to achieve histological response (sens 0.68; spec 0.70). Those achieving a 30% relative reduction in liver fat were ∼4 times more likely to achieve a histological response (sens 0.77; spec 0.53). CONCLUSIONS: These results, from three combined drug trials, demonstrate that changes in multiparametric MRI markers of liver health (cT1 and PDFF) can predict histological response for steatohepatitis following therapeutic intervention. IMPACT AND IMPLICATIONS: There is great interest in identifying suitable biomarkers that can be used to replace liver biopsy, or to identify those patients who would benefit from one, in both the clinical management of MASH and in drug development. We investigated the utility of two MRI-derived non-invasive tests, iron corrected T1 mapping (cT1) and liver fat content from proton density fat fraction (PDFF), to predict histological improvement in patients who had undergone experimental treatment for MASH. Using data from 150 people who participated in one of three clinical trials, we observed that a reduction in cT1 by over 80 ms and a relative reduction in PDFF of over 58% were the optimal thresholds for change that predicted resolution of steatohepatitis. PDFF as a marker of liver fat, and cT1 as a specific measure of liver disease activity, are both effective at identifying those who are likely responding to drug interventions and experiencing improvements in overall liver health. CLINICAL TRIAL NUMBER(S): NCT02443116, NCT03976401, NCT03551522.

ESR Essentials: advanced MR safety in vulnerable patients-practice recommendations by the European Society for Magnetic Resonance in Medicine and Biology.

For every patient, the MR safety evaluation should include the assessment of risks in three key areas, each corresponding to a specific hazard posed by the electromagnetic fields generated by the MR scanner: ferromagnetic attraction and displacement by the static field; stimulation, acoustic noise, and device interaction by the gradient fields; and bulk and focal heating by the radiofrequency field. MR safety guidelines and procedures are typically designed around the "average" patient: adult, responsive, and of typical habitus. For this type of patient, we can safely expect that a detailed history can identify metallic objects inside and outside the body, verbal contact during the scan can detect signs of discomfort from heating or acoustic noise, and safety calculations performed by the scanner can prevent hyperthermia. However, for some less common patient categories, these assumptions do not hold. For instance, patients with larger habitus, febrile patients, or pregnant people are more subject to bulk heating and require more conservative MR protocols, while at the same time presenting challenges during positioning and preparation. Other vulnerable categories are infants, children, and patients unable to communicate, who might require screening for ferromagnetic objects with other imaging modalities or dedicated equipment. This paper will provide guidance to implement appropriate safety margins in the workflow and scanning protocols in various vulnerable patient categories that are sometimes overlooked in basic MR safety guidance documents. CLINICAL RELEVANCE STATEMENT: Special care in the implementation of MR safety procedures is of paramount importance in the handling of patients. While most institutions have streamlined operations in place, some vulnerable patient categories require specific considerations to obtain images of optimal quality while minimizing the risks derived by exposure to the MR environment. KEY POINTS: Patients unable to effectively communicate need to be carefully screened for foreign objects. Core temperature management is important in specific patient categories. There are no hard quantitative criteria that make a patient fall into a specific vulnerable category. Protocols and procedures need to be adaptable.

Assessing the performance of AI-assisted technicians in liver segmentation, Couinaud division, and lesion detection: a pilot study.

BACKGROUND: In patients with primary and secondary liver cancer, the number and sizes of lesions, their locations within the Couinaud segments, and the volume and health status of the future liver remnant are key for informing treatment planning. Currently this is performed manually, generally by trained radiologists, who are seeing an inexorable growth in their workload. Integrating artificial intelligence (AI) and non-radiologist personnel into the workflow potentially addresses the increasing workload without sacrificing accuracy. This study evaluated the accuracy of non-radiologist technicians in liver cancer imaging compared with radiologists, both assisted by AI. METHODS: Non-contrast T1-weighted MRI data from 18 colorectal liver metastasis patients were analyzed using an AI-enabled decision support tool that enables non-radiology trained technicians to perform key liver measurements. Three non-radiologist, experienced operators and three radiologists performed whole liver segmentation, Couinaud segment segmentation, and the detection and measurements of lesions aided by AI-generated delineations. Agreement between radiologists and non-radiologists was assessed using the intraclass correlation coefficient (ICC). Two additional radiologists adjudicated any lesion detection discrepancies. RESULTS: Whole liver volume showed high levels of agreement between the non-radiologist and radiologist groups (ICC = 0.99). The Couinaud segment volumetry ICC range was 0.77-0.96. Both groups identified the same 41 lesions. As well, the non-radiologist group identified seven more structures which were also confirmed as lesions by the adjudicators. Lesion diameter categorization agreement was 90%, Couinaud localization 91.9%. Within-group variability was comparable for lesion measurements. CONCLUSION: With AI assistance, non-radiologist experienced operators showed good agreement with radiologists for quantifying whole liver volume, Couinaud segment volume, and the detection and measurement of lesions in patients with known liver cancer. This AI-assisted non-radiologist approach has potential to reduce the stress on radiologists without compromising accuracy.

Multi-organ abnormalities assessed by a single MRI scan in individuals with blood cancer.

BACKGROUND: During the COVID-19 pandemic individuals with all blood cancers were classified as clinically vulnerable and at high risk of complications and death. Our study sought to determine if individuals with specific blood cancers were at a heightened risk of longer term organ impairment, secondary to SARS-CoV-2 infection. METHODS: We set up a prospective observational study, utilising quantitative multi-parametric MRI to determine organ health over time in patients with specific blood cancers who had recovered from COVID-19. RESULTS: Multi-organ abnormality was more prevalent in blood cancer patients than in healthy controls (42 % vs 6 % p < 0.001) but comparable to the long COVID controls (42 % vs 33 %, p > 0.05). At 6 month follow up scans, organ abnormalities persisted in most individuals with blood cancer (71 % ≥1 organ and 52 % multi-organ). CONCLUSION: A multi-organ MRI platform offers the capacity to accurately evaluate organ health dynamically in blood cancers and detect asymptomatic organ impairment. The application of multi-organ MRI could aid early detection and longitudinal monitoring of organ impairment, potentially guiding more personalised treatment strategies and improving clinical outcomes in many rare diseases.

Quantitative Imaging Reveals Steatosis and Fibroinflammation in Multiple Organs in People With Type 2 Diabetes: A Real-World Study.

We aimed to determine the extent of multiorgan fat accumulation and fibroinflammation in individuals living with type 2 diabetes. We deeply phenotyped individuals with type 2 diabetes (134 from secondary care, 69 from primary care) with multiorgan, quantitative, multiparametric MRI and compared with 134 matched control individuals without diabetes and 92 control individuals with normal weight. We examined the impact of diabetes duration, obesity status, and glycemic control. Ninety-three of the individuals with type 2 diabetes were reevaluated at 7 months (median). Multiorgan abnormalities were more common in individuals with type 2 diabetes (94%) than in age- and BMI-matched healthy individuals or healthy individuals with normal weight. We demonstrated a high burden of combined steatosis and fibroinflammation within the liver, pancreas, and kidneys (41%, 17%, and 10%) associated with visceral adiposity (73%) and poor vascular health (82%). Obesity was most closely associated with advanced liver disease, renal and visceral steatosis, and multiorgan abnormalities, while poor glycemic control was associated with pancreatic fibroinflammation. Pharmacological therapies with proven cardiorenal protection improved liver and vascular health unlike conventional glucose-lowering treatments, while weight loss or improved glycemic control reduced multiorgan adiposity (P ≤ 0.01). Quantitative imaging in people with type 2 diabetes highlights widespread organ abnormalities and may provide useful risk and treatment stratification.

The Effects of Intensive Rehabilitation Combined with Thiamine Treatment on Cognitive Recovery in a Case of Non-Alcoholic Wernicke-Korsakoff Syndrome.

Wernicke-Korsakoff Syndrome (WKS) is a severe neurological disorder resulting from thiamine deficiency, commonly associated with alcohol consumption but also stemming from dietary imbalances or other clinical conditions. Cognitive deficits, affecting memory and executive functions, pose a serious concern, with partial recovery often not complete. A 28-year-old woman underwent surgery for acute necrotizing hemorrhagic pancreatitis, leading to admission for post-acute intensive treatment due to prolonged bed rest syndrome. Clinical examinations revealed sensory-motor neuropathy, denervation in the active phase, mammillary body hyperintensity, and cognitive impairment. The patient exhibited poor orientation, lacked awareness of her clinical condition, and experienced impaired nonverbal memory, practical constructive issues, and planning difficulties-consistent with WKS. The patient received high-dose thiamine (300 mg TDS), coupled with daily physiokinesitherapy and occupational therapy. A final neuropsychological evaluation three months later showed substantial remission of executive and memory difficulties, improved spatial-temporal orientation, and enhanced awareness. The complex case required timely multidisciplinary intervention for accurate diagnosis and effective rehabilitation. The patient experienced rapid clinical improvement and cognitive recovery with high-dose thiamine and physiotherapy.

The beneficial role of nano-sized Fe3O4 entrapped in ultra-stable Y zeolite for the complete mineralization of phenol by heterogeneous photo-Fenton under solar light.

Highly efficient, separable, and stable magnetic iron-based-photocatalysts produced from ultra-stable Y (USY) zeolite were applied, for the first time, to the photo-Fenton removal of phenol under solar light. USY Zeolite with a Si/Al molar ratio of 385 was impregnated under vacuum with an aqueous solution of Fe2+ ions and thermally treated (500-750 °C) in a reducing atmosphere. Three catalysts, Fe-USY500°C-2h, Fe-USY600°C-2h and Fe-USY750°C-2h, containing different amounts of reduced iron species entrapped in the zeolitic matrix, were obtained. The catalysts were thoroughly characterized by absorption spectrometry, X-ray powder diffraction with synchrotron source, followed by Rietveld analysis, X-ray photoelectron spectroscopy, N2 adsorption/desorption at -196 °C, high-resolution transmission electron microscopy and magnetic measurements at room temperature. The catalytic activity was evaluated in a recirculating batch photoreactor irradiated by solar light with online analysis of evolved CO2. Photo-Fenton results showed that the catalyst obtained by thermal treatment at 500 °C for 2 h under a reducing atmosphere (FeUSY-500°C-2h) was able to completely mineralize phenol in 120 min of irradiation time at pH = 4 owing to the presence of a higher content of entrapped nano-sized magnetite particles. The latter promotes the generation of hydroxyl radicals in a more efficient way than the Fe-USY catalysts prepared at 600 and 750 °C because of the higher Fe3O4 content in ultra-stable Y zeolite treated at 500 °C. The FeUSY-500°C-2h catalyst was recovered from the treated water through magnetic separation and reused five times without any significant worsening of phenol mineralization performances. The characterization of the FeUSY-500°C-2h after the photo-Fenton process demonstrated that it was perfectly stable during the reaction. The optimized catalyst was also effective in the mineralization of phenol in tap water. Finally, a possible photo-Fenton mechanism for phenol mineralization was assessed based on experimental tests carried out in the presence of scavenger molecules, demonstrating that hydroxyl radicals play a major role.

Multi-organ impairment and long COVID: a 1-year prospective, longitudinal cohort study.

OBJECTIVES: To determine the prevalence of organ impairment in long COVID patients at 6 and 12 months after initial symptoms and to explore links to clinical presentation. DESIGN: Prospective cohort study. PARTICIPANTS: Individuals. METHODS: In individuals recovered from acute COVID-19, we assessed symptoms, health status, and multi-organ tissue characterisation and function. SETTING: Two non-acute healthcare settings (Oxford and London). Physiological and biochemical investigations were performed at baseline on all individuals, and those with organ impairment were reassessed. MAIN OUTCOME MEASURES: Primary outcome was prevalence of single- and multi-organ impairment at 6 and 12 months post COVID-19. RESULTS: A total of 536 individuals (mean age 45 years, 73% female, 89% white, 32% healthcare workers, 13% acute COVID-19 hospitalisation) completed baseline assessment (median: 6 months post COVID-19); 331 (62%) with organ impairment or incidental findings had follow-up, with reduced symptom burden from baseline (median number of symptoms 10 and 3, at 6 and 12 months, respectively). Extreme breathlessness (38% and 30%), cognitive dysfunction (48% and 38%) and poor health-related quality of life (EQ-5D-5L < 0.7; 57% and 45%) were common at 6 and 12 months, and associated with female gender, younger age and single-organ impairment. Single- and multi-organ impairment were present in 69% and 23% at baseline, persisting in 59% and 27% at follow-up, respectively. CONCLUSIONS: Organ impairment persisted in 59% of 331 individuals followed up at 1 year post COVID-19, with implications for symptoms, quality of life and longer-term health, signalling the need for prevention and integrated care of long COVID.Trial Registration: ClinicalTrials.gov Identifier: NCT04369807.

Use of Zeolites in the Capture and Storage of Thermal Energy by Water Desorption-Adsorption Cycles.

In this work, four zeolite-bearing materials (three naturally occurring and one of synthetic origin) were considered for thermal energy capture and storage. Such materials can store thermal energy as heat of desorption of the water present therein, heat that is given back when water vapor is allowed to be re-adsorbed by zeolites. This study was carried out by determining the loss of water after different activation thermal treatments, the water adsorption kinetics and isotherm after an activation step of the zeolites, the intergranular and intragranular porosity, and the thermal conductivity of the zeolite-bearing materials. Moreover, the thermal stability of the framework of the zeolites of the four materials tested was investigated over a large number of thermal cycles. The results indicate that zeolite 13X was the most suitable material for thermal energy storage and suggest its use in the capture and storage of thermal energy that derives from thermal energy waste.

Silica Meets Tannic Acid: Designing Green Nanoplatforms for Environment Preservation.

Hybrid tannic acid-silica-based porous nanoparticles, TA-SiO2 NPs, have been synthesized under mild conditions in the presence of green and renewable tannic acid biopolymer, a glycoside polymer of gallic acid present in a large part of plants. Tannic acid (TA) was exploited as both a structuring directing agent and green chelating site for heavy metal ions recovery from aqueous solutions. Particles morphologies and porosity were easily tuned by varying the TA initial amount. The sample produced with the largest TA amount showed a specific surface area an order of magnitude larger than silica nanoparticles. The adsorption performance was investigated by using TA-SiO2 NPs as adsorbents for copper (II) ions from an aqueous solution. The effects of the initial Cu2+ ions concentration and the pH values on the adsorption capability were also investigated. The resulting TA-SiO2 NPs exhibited a different adsorption behaviour towards Cu2+, which was demonstrated through different tests. The largest adsorption (i.e., ~50 wt% of the initial Cu2+ amount) was obtained with the more porous nanoplatforms bearing a higher final TA content. The TA-nanoplatforms, stable in pH value around neutral conditions, can be easily produced and their use would well comply with a green strategy to reduce wastewater pollution.

Removal of sulfanilamide by tailor-made magnetic metal-ceramic nanocomposite adsorbents.

Three tailor-made magnetic metal-ceramic nanocomposites, obtained from zeolite A (ZA1 and ZA2) and a natural clinoptilolite (LB1), have been used as adsorbents to remove sulfanilamide (SA), a sulfonamide antibiotic of common use, from water. A patented process for the synthesis of nanocomposites has been suitably modified to maximize the efficiency of the SA removal, as well as to extend the applicability of the materials. The role played by the main process parameters (kinetic, pH, initial concentration of SA) has been characterized. The significant effect of the pH on the SA removal has been explained identifying two possibly coexisting mechanisms of SA adsorption, based on polar and hydrophobic interactions, respectively. The adsorption kinetics have been in all cases described by the pseudo second-order model. The adsorption isotherms obtained with ZA1 have been satisfactorily described by the Langmuir model, suggesting a monolayer adsorption of SA on the magnetic nanocomposites resulting from a uniform surface energy. The isotherms obtained with LB1 could be described by a more complex approach, deriving by the additive superposition of Langmuir and Sips models. In order to ensure an effective removal of the antibiotic and a proper recycle of the magnetic adsorbents, a sustainable regeneration procedure of the exhausted adsorbent has been developed, based on the treatment with a dilute solution of NaOH.

Thermodilatometric Study of the Decay of Zeolite-Bearing Building Materials.

Six zeolite-bearing rocks, often used as building materials, were analyzed by thermodilatometry, together with a rock not bearing zeolites and a plaster covering a containing wall made of zeolite-bearing dimension stones, up to 250 °C. The main results obtained were the following: (i) the zeolite-bearing rocks exhibited very small, if any, positive variation of ΔL/Lo (%) up to about 100 °C, whereas they more or less shrank in the temperature range 100-250 °C (final values ranging from -0.21 to -0.92%); (ii) the rock not bearing zeolites regularly expanded through the whole temperature range, attaining a final value of 0.19%; (iii) the plaster showed a thermodilatometric behavior strongly affected by its water content. Obtained results were interpreted based on plain thermal expansion, shrinkage by dehydration, cation migration and thermal collapse of the zeolitic structure. The decay of the zeolite-bearing building materials was essentially related to: (i) the large differences recorded in the thermodilatometric behavior of the various rocks and the plaster; (ii) the different minerogenetic processes that resulted in the deposition of the various zeolite-bearing rocks.

On the optimal temporal resolution for phase contrast cardiovascular magnetic resonance imaging: establishment of baseline values.

BACKGROUND: The aim of this study is to quantify the frequency content of the blood velocity waveform in different body regions by means of phase contrast (PC) cardiovascular magnetic resonance (CMR) and Doppler ultrasound. The highest frequency component of the spectrum is inversely proportional to the ideal temporal resolution to be used for the acquisition of flow-sensitive imaging (Shannon-Nyquist theorem). METHODS: Ten healthy subjects (median age 33y, range 24-40) were scanned with a high-temporal-resolution PC-CMR and with Doppler ultrasound on three body regions (carotid arteries, aorta and femoral arteries). Furthermore, 111 patients (median age 61y) with mild to moderate arterial hypertension and 58 patients with aortic aregurgitation, atrial septal defect, or repaired tetralogy of Fallot underwent aortic CMR scanning. The frequency power distribution was calculated for each location and the maximum frequency component, fmax, was extracted and expected limits for the general population were inferred. RESULTS: In the healthy subject cohort, significantly different fmax values were found across the different body locations, but they were nonsignificant across modalities. No significant correlation was found with heart rate. The measured fmax ranged from 7.7 ± 1.1 Hz in the ascending aorta, up to 12.3 ± 5.1 Hz in the femoral artery (considering PC-CMR data). The calculated upper boundary for the general population ranged from 11.0 Hz to 27.5 Hz, corresponding to optimal temporal resolutions of 45 ms and 18 ms, respectively. The patient cohort exhibited similar values for the frequencies in the aorta, with no correlation between blood pressure and frequency content. CONCLUSIONS: The temporal resolution of PC-CMR acquisitions can be adapted based on the scanned body region and in the adult population, should approach approximately 20 ms in the peripheral arteries and 40 ms in the aorta. TRIAL REGISTRATION: This study presents results from a restrospective analysis of the clinical study NCT01870739 (ClinicalTrials.gov).

Separation of Biological Entities From Human Blood by Using Magnetic Nanocomposites Obtained From Zeolite Precursors.

In this work, three novel magnetic metal-ceramic nanocomposites were obtained by thermally treating Fe-exchanged zeolites (either A or X) under reducing atmosphere at relatively mild temperatures (750-800 °C). The so-obtained materials were thoroughly characterized from the point of view of their physico-chemical properties and, then, used as magnetic adsorbents in the separation of the target gene factors V and RNASE and of the Staphylococcus aureus bacteria DNA from human blood. Such results were compared with those obtained by using a top ranking commercial separation system (namely, SiMAG-N-DNA by Chemicell). The results obtained by using the novel magnetic adsorbents were similar to (or even better than) those obtained by using the commercial system, both during manual and automated separations, provided that a proper protocol was adopted. Particularly, the novel magnetic adsorbents showed high sensitivity during tests performed with small volumes of blood. Finally, the feasible production of such magnetic adsorbents by an industrial process was envisaged as well.

Dynamic MR imaging of the skeletal muscle in young and senior volunteers during synchronized minimal neuromuscular electrical stimulation.

OBJECTIVE: Neuromuscular electrical stimulation (NMES)-induced isometric contraction is feasible during MRI and can be combined with acquisition of volumetric dynamic MR data, in a synchronous and controlled way. Since NMES is a potent resource for rehabilitation, MRI synchronized with NMES presents a valuable validation tool. Our aim was to show how minimal NMES-induced muscle contraction characterization, as evaluated through phase-contrast MRI, differs between senior and young volunteers. MATERIALS AND METHODS: Simultaneous NMES of the quadriceps muscle and phase-contrast imaging were applied at 3 T to 11 senior (75 ± 3 years) and 12 young volunteers (29 ± 7 years). A current sufficient to induce muscle twitch without knee extension was applied to both groups. RESULTS: Strain vectors were extracted from the velocity fields and strain datasets were compared with non-parametric tests and descriptive statistics. Strain values were noticeably different between both groups at both current intensities and significant differences were observed for similar current level. DISCUSSION: In conclusion, NMES-synchronized MRI could be successfully applied in senior volunteers with strain results clearly different from the younger volunteers. Also, differences within the senior group were detected both in the magnitude of strain and in the position of maximum strain pixels.

Synchronous MRI of muscle motion induced by electrical stimulation.

PURPOSE: Assessing the functionality of muscle fibers is essential to monitor both pathological and physiological processes. Here, we present a new method for accurate, quantitative measurement of muscle contraction with magnetic resonance imaging (MRI) using an electrical muscle stimulator (EMS), hence allowing the direct assessment of muscle kinematics. METHODS: A commercially available EMS device was used to induce involuntary periodic muscle contraction of the vastus lateralis muscle (VL) synchronized with high-temporal-resolution cine phase contrast MRI acquisition at 3T. The proposed method was evaluated in ten male volunteers at varying levels of stimulation (10-18 mA) and maximum velocity, strain, and strain rate were calculated offline. RESULTS: Artifact-free velocity, strain and strain rate maps were produced and were consistent across the volunteers. Quantitatively, all parameters varied significantly at different levels of stimulation, in an approximately power-law dependence on the stimulation current. At 18 mA maximum contraction speeds at the beginning of the contraction were 4.28 ± 2.64 cm/s; principal strain was 0.30 ± 0.12; and positive in-plane strain rate was 0.25 ± 0.14 s-1 . CONCLUSION: MRI of EMS-controlled involuntary muscle contraction is feasible and allows offline calculation of velocity, strain and strain rate maps, which appear to depend significantly on the stimulation current used. Magn Reson Med 77:664-672, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Preparation and Characterization of Magnetic and Porous Metal-Ceramic Nanocomposites from a Zeolite Precursor and Their Application for DNA Separation.

In this work, metal-ceramic nanocomposites were obtained through short (up to 2 h) thermal treatments at relatively moderate temperatures (750­800 °C) under a reducing atmosphere, using Fe-exchanged zeolite A as the precursor. The as-obtained materials were characterized by X-ray powder diffraction analysis, N2 adsorption at ­196 °C, and highresolution transmission electron microscopy. The results of these analyses showed that the nanocomposites consisted of a dispersion of metallic Fe nanoparticles within a porous ceramic matrix, mainly based on amorphous silica and alumina. These nanocomposites were magnetically characterized, and their magnetic response was studied. Finally, the obtained metal-ceramic nanocomposite materials were used in the separation of Escherichia coli DNA from a crude cell lysate. The results of the DNA separation experiments showed that the obtained materials could perform this type of separation.

Application of highly porous materials for simazine removal from aqueous solutions.

The removal of simazine from both pure water and solute-bearing well water was studied by adsorption on two solids: zeolite H-Y from the commercial Na form and porous silica tailored by the sol-gel technique. The pH dependence of the amount adsorbed in a closed system at constant total simazine content as well as the apparent isotherms of adsorption was measured in all four cases. The low ion content of natural water suffices to alter the adsorption features in the case of silica, but not with zeolite H-Y. Iteration of the adsorption process onto constant amounts of solid allowed bringing the residual simazine concentration below 0.05 mg/L, the value allowed by Italian laws in wastewaters.

Feasibility of Dose Optimization in a Second-Generation Dual-Source CT Scanner for a Manufacturer-Recommended Urolithiasis Protocol for Imaging Renal Stones.

OBJECTIVE: The purpose of this article is to investigate the magnitude of dose optimization for a manufacturer-recommended urolithiasis protocol in a second-generation dual-source CT scanner. MATERIALS AND METHODS: Custom renal phantoms with 24 stones were scanned using the manufacturer-provided dual-energy CT protocol (tube A, 100 kVp and 210 reference mAs; tube B, 140 kVp and 162 reference mAs) and seven dose-optimized protocols in which the reference tube current-time product setting of tube A was reduced stepwise by 20 mAs. Detection and characterization of the stones was assessed. In the patient study, 25 patients underwent the manufacturer-provided dual-energy protocol and 25 patients underwent imaging with a dose-optimized protocol (tube A, 100 kVp and 90 reference mAs; tube B, 140 kVp and 70 reference mAs). Dose-length product (DLP), image noise, and contrast-to-noise ratio (CNR) were assessed. Subjective image quality was analyzed by three independent radiologists. RESULTS: In the phantom study, the reference tube current-time product of tube A could be reduced from 210 to 90 mAs without losing the accuracy of detection or characterization of the calculi. In the patient study, the dose-optimized protocol resulted in a significant reduction of the average DLP by 51% compared with the standard protocol (219.4 vs 443.5 mGy·cm, respectively; p = 0.0001). The image noise was higher, and the CNR was lower, in the dose-optimized group than in the standard-dose group (p < 0.05). The subjective overall image quality of the dose-optimized CT examinations was rated as good, and that of the standard-dose CT examinations was rated as excellent (p = 0.001). CONCLUSION: The in vitro and in vivo assessment revealed a potential for a 51% dose reduction of the manufacturer-recommended dual-energy CT protocol for urolithiasis without compromising the accuracy.