Machine learning identifies liver fat fraction (FF) measured by 1H MR spectroscopy, insulinemia, and elastography as robust, non-invasive biomarkers for diagnosing steatohepatitis in liver transplant patients, validated through decision tree analysis. Compared to the general population (~5.8% prevalence), MASH is significantly more common in liver transplant recipients (~30%-50%). In patients with FF > 5.3%, the positive predictive value for MASH ranged up to 97%, more than twice the value observed in the general population.
- MeSH
- dospělí MeSH
- elastografie MeSH
- játra * patologie diagnostické zobrazování MeSH
- lidé středního věku MeSH
- lidé MeSH
- strojové učení * MeSH
- transplantace jater * MeSH
- ztučnělá játra * diagnóza diagnostické zobrazování MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE: This prospective pilot study aims to evaluate the capabilities of novel quantitative ultrasound (QUS) methods based on attenuation (Att.PLUS) and sound speed (SSp.PLUS) for detecting liver fat. PATIENTS AND METHODS: The study included 56 individuals with biopsy-proven steatosis (percutaneous liver biopsy) ranging from 0 % to 90 % of hepatocytes containing intracellular lipid vacuoles. Histopathology was considered reference standard. Abdominal QUS examinations were conducted using Att.PLUS and SSp.PLUS techniques on the Aixplorer MACH 30 system. Comparative assessments were made using the results of liver biopsy and magnetic resonance spectroscopy (MRS) together with magnetic resonance imaging proton density fat fraction (MRI-PDFF). MR examinations were performed on the Siemens VIDA 3 T system. RESULTS: ROC analysis was conducted for two groups: (a) patients without steatosis (S0) versus those with steatosis (S1 + S2 + S3) yielded AUC values of 0.79 for Att.PLUS and 0.78 for SSp.PLUS, in contrast to an AUC > 0.95 for MRS and MRI-PDFF; and (b) patients without or with mild steatosis (S0 + S1) versus those with severe steatosis (S2 + S3), yielded AUC values of 0.93 for Att.PLUS and 0.89 for SSp.PLUS, in contrast to an AUC > 0.99 for MRS and MRI-PDFF. However, MR methods were superior in detecting liver fat content in obese patients and post-liver transplantation individuals. CONCLUSION: Both QUS parameters (Att.PLUS and SSp.PLUS) appear equivalent at differentiating S0 vs. (S1 + S2 + S3) patients, but the Att.PLUS parameter may be more effective at identifying advanced steatosis (S2 + S3). MR techniques outperformed QUS methods, making them more suitable for clinical studies.
- MeSH
- biopsie MeSH
- dospělí MeSH
- játra diagnostické zobrazování patologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie metody MeSH
- magnetická rezonanční tomografie * metody MeSH
- pilotní projekty MeSH
- prospektivní studie MeSH
- reprodukovatelnost výsledků MeSH
- senioři MeSH
- senzitivita a specificita MeSH
- ultrasonografie * metody MeSH
- ztučnělá játra * diagnostické zobrazování patologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Background: Metabolic-dysfunction-associated steatotic liver disease (MASLD) represents a major clinical complication of obesity. Methods: In this study, we used magnetic resonance (MR) methods to determine the effect of obesity treatment with semaglutide, a GLP-1 receptor agonist, on the liver fat content and selected metabolic variables. We investigated whether treatment would affect the acute response of liver fat to glucose and fructose administration and whether it would affect the fatty acid profile of VLDL-triglycerides. Sixteen obese non-diabetic men underwent a 16-week dietary intervention and 16-week treatment with subcutaneous semaglutide in a crossover design without a washout period. The order of the interventions was randomized. Results: After treatment, body weight of the subjects decreased by 5% and liver fat by a third, whereas dietary intervention had no impact on these parameters. The decrease in liver fat with semaglutide did not correlate with changes in body weight and other measures of adiposity and was unrelated to improved insulin sensitivity. Conclusions: The proportion of palmitic and palmitoleic acids in VLDL-triglycerides decreased after treatment, suggesting that the beneficial effects of semaglutide on liver fat are mediated by the suppression of de novo lipogenesis.
- Publikační typ
- časopisecké články MeSH
BACKGROUND: During and after exercise, dynamic 31 P MR parameters are typically measured using an MR-compatible ergometer. Self-built equipment for local condition can be constructed where possible. PURPOSE: To develop a pedal resistance ergometer with rocker arm based on a system that combines electric weight displacement, visual self-monitoring, and exercise triggering. The repeatability and reproducibility were tested. METHODS: The hardware and software for the ergometer were constructed from commercial components in a home laboratory. Twelve volunteers participated in the testing of the ergometer. RESULTS: A fully automated ergometer system was developed, allowing the pedal resistance to be adjusted during the examination. The system includes a self-monitoring and triggering mechanism that enables both the operator and subject to monitor pedal frequency and force. The operator can modify the pedal resistance as desired during the exercise. This self-monitoring solution is simple and cost-effective, requiring only a commercial potentiometer, an Arduino converter, and a conventional video projector with a personal computer (PC). Additionally, all system components are located outside the magnetic resonance (MR) room, avoiding interference with the MR system. Results of several test of the reproducibility/repeatability of power at three pedal resistance values (15%, 24%, 25% maximal voluntary force) were expressed both as a coefficient of variation ranging from 6% to 3.1% and as an intraclass correlation of coefficient ranging from 0.96 to 0.99. Similar values were also found for other dynamic parameters of 31 P MR spectroscopy. These findings are similar to published data obtained on different types of ergometers. CONCLUSIONS: Based on more than 1 year of usage, the ergometer proved successful in handling stationary and variable loads, and can be easily operated by a single user.
Most in vivo 31P MR studies are realized on 3T MR systems that provide sufficient signal intensity for prominent phosphorus metabolites. The identification of these metabolites in the in vivo spectra is performed by comparing their chemical shifts with the chemical shifts measured in vitro on high-field NMR spectrometers. To approach in vivo conditions at 3T, a set of phantoms with defined metabolite solutions were measured in a 3T whole-body MR system at 7.0 and 7.5 pH, at 37 °C. A free induction decay (FID) sequence with and without 1H decoupling was used. Chemical shifts were obtained of phosphoenolpyruvate (PEP), phosphatidylcholine (PtdC), phosphocholine (PC), phosphoethanolamine (PE), glycerophosphocholine (GPC), glycerophosphoetanolamine (GPE), uridine diphosphoglucose (UDPG), glucose-6-phosphate (G6P), glucose-1-phosphate (G1P), 2,3-diphosphoglycerate (2,3-DPG), nicotinamide adenine dinucleotide (NADH and NAD+), phosphocreatine (PCr), adenosine triphosphate (ATP), adenosine diphosphate (ADP), and inorganic phosphate (Pi). The measured chemical shifts were used to construct a basis set of 31P MR spectra for the evaluation of 31P in vivo spectra of muscle and the liver using LCModel software (linear combination model). Prior knowledge was successfully employed in the analysis of previously acquired in vivo data.
- MeSH
- adenosindifosfát metabolismus MeSH
- adenosintrifosfát metabolismus MeSH
- fosfatidylcholiny metabolismus MeSH
- fosfatidylethanolaminy metabolismus MeSH
- fosfáty metabolismus MeSH
- fosfor metabolismus MeSH
- játra metabolismus MeSH
- kosterní svaly metabolismus MeSH
- lidé MeSH
- nukleární magnetická rezonance biomolekulární * MeSH
- pilotní projekty MeSH
- software * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
Increased hepatic fat content (HFC) is a hallmark of non-alcoholic fatty liver (NAFL) disease, a common condition in liver transplant recipients. Proton MR spectroscopy (1H MRS) and MR imaging-based proton density fat fraction as the only diagnosis modality enable precise non-invasive measurement of HFC and, also, fatty acid profiles in vivo. Using 1H MRS at 3T, we examined 47 liver transplantation candidates and 101 liver graft recipients. A point-resolved spectroscopy sequence was used to calculate the steatosis grade along with the saturated, unsaturated and polyunsaturated fractions of fatty acids in the liver. The steatosis grade measured by MRS was compared with the histological steatosis grade. HFC, represented by fat fraction values, is adept at distinguishing non-alcoholic steatohepatitis (NASH), NAFL and non-steatotic liver transplant patients. Relative hepatic lipid saturation increases while unsaturation decreases in response to increased HFC. Additionally, relative hepatic lipid saturation increases while unsaturation and polyunsaturation both decrease in liver recipients with histologically proven post-transplant NASH or NAFL compared to non-steatotic patients. HFC, measured by in vivo 1H MRS, correlated well with histological results. 1H MRS is a simple and fast method for in vivo analysis of HFC and its composition. It provides non-invasive support for NAFL and NASH diagnoses.
- Publikační typ
- časopisecké články MeSH
The article describes the determination of the amount of fat in liver tissue (steatosis) by non-invasive methods of 1H magnetic resonance (MR) spectroscopy and MR imaging in vivo on whole body tomographs. Commercially available PRESS, STEAM and HISTO techniques for 1H MR spectroscopy and 3D-Dixon techniques for MR imaging on a 3T MR tomograph were used. The accuracy and usability of individual techniques were verified on prepared lipid phantoms in the concentration range of 2.5–30% fat and on a representative group of volunteers. It turns out that MR spectroscopic and imaging methods are currently fully comparable.
Cíl: Porovnat spektroskopické metody stanovení steatózy sekvencemi PRESS, STEAM a HISTO na 3T tomografech TRIO a VIDA. Metodika: Byla naměřena 1H MR spektra jater dobrovolníků na 3T tomografech Siemens TRIO a VIDA (45/25 subjektů) sekvencemi PRESS s TE = 30/33 ms, STEAM s TE = 20/33 ms a metodou HISTO s TE = 12-72 ms. Stejné sekvence byly použity pro stanovení T2 lipidů a vody. Spektra byla zpracována programem LCModel. Frakční (FF) a objemové (HFC) zlomky (%) byly korigovány individuálními a průměrnými hodnotami relaxačních časů T2. Analýza výsledků byla provedena korelační, regresní a Bland-Altmanovou metodou. Výsledky: Relaxační časy T2 snižují hodnoty parametrů FF a HFC až o cca 47 % při použití nominálních T2. Regresní analýza a Bland-Altmanovy grafy ukazují, že parametry získané technikami PRESS, STEAM a HISTO s TE 20 a 33 ms na VIDA jsou srovnatelné. Byly změřeny hodnoty T2 lipidů mezi 45-53 ms a T2 vody mezi 24-31 ms. Byly stanoveny limitní hodnoty FF pro určení stupně steatózy u transplantovaných pacientů v těchto rozsazích: S0: < 0,8 %; S1: 0,81-6,2 %; S2: 6,21-16,5 %; S3: > 16,5 %. Závěr: Získané hodnoty FF a HFC jsou citlivé na T2 korekce a použití průměrných hodnot T2 dává vyšší hodnoty parametrů FF a HFC. Bland-Altmanovy grafy ukazují na dobrou shodu metod STEAM, PRESS a HISTO. Limitní hodnoty pro stanovení stupně steatózy u transplantovaných pacientů z výsledků HISTO metody jsou v rozmezí literárních hodnot.
Aim: To compare MR spectroscopic methods for steatosis determination by PRESS, STEAM and HISTO sequences on 3T TRIO and VIDA tomographs. Method: 1H MR spectra of the liver of volunteers were measured on 3T tomographs Siemens TRIO and VIDA (45/25 subjects). The sequences PRESS with TE = 30/33 ms, STEAM with TE = 20/33 ms and the HISTO method with TE = 12-72 ms were used. The same sequences were used to determine T2 of lipids and water. The spectra were processed using the LCModel method. Fractional (FF) and volume (HFC) fractions (%) were corrected for individual and mean T2 values. Correlation, regression and Bland-Altman data analyses were performed. Results: Relaxation times T2 reduce FF and HFC values by up to approx. 47%. Regression analysis and Bland-Altman graphs show that the parameters obtained by PRESS, STEAM and HISTO techniques with short TE are comparable on VIDA. Mean T2 values of lipids between 45 and 53 ms and T2 of water between 24 and 31 ms were measured. HISTO FF cut-off values for the degree of steatosis in transplant patients were set in the following ranges: S0: < 0.8%; S1: 0.81-6.2%; S2: 6.21-16.5%; S3: > 16.5%. Conclusion: The obtained FF and HFC values are sensitive to T2 corrections. Bland-Altman´s graphs indicate good agreement among STEAM, PRESS and HISTO methods. Limit values for the steatosis degree in transplant patients from the result of the HISTO method agree with literature values.
Cíl: Představujeme radiofrekvenční objemovou cívku s pracovním objemem 100 ml pro in vivo 1H a 19F MR zobrazování malých hlodavců na 4,7 T experimentálním spektrometru. Metodika: Cívka je konstrukce typu birdcage s jednokanálovým buzením a dvanácti podélnými elementy vytvářejícími homogenní elektromagnetické pole B1 v cívce. Od běžně konstruovaných birdcage cívek se cívka prezentovaná v tomto článku odlišuje možností změny rezonanční frekvence ve velkém frekvenčním rozsahu (zahrnujícím f019F= 188,6 - f01H= 200,4 MHz @ B0 4,7 T), což je umožněno unikátním řešením změny elektrické kapacity mezi vodiči prostřednictvím změny délky cívky. Výsledky: Hodnoty faktoru kvality v rezonancích pro nezatíženou cívku jsou Q1H = 328 a Q19F= 331. Tyto výsledky jsou srovnatelné s hodnotami běžného typu konstrukce birdcage cívek určených pouze pro jednu z rezonančních frekvencí. Prezentovaná cívka však umožňuje nejen měření 1H, ale i 19F snímků se srovnatelným MR signálem bez nutnosti výměny cívek mezi jednotlivými měřeními. Závěr: Obě taková měření tedy mohou být provedena s identickou polohou vzorku nebo hlodavce.
Aim: We present a radio frequency volume coil with a working volume of 100 ml for in vivo 1H and 19F MR imaging of small rodents on a 4.7 T experimental spectrometer. The coil has a single-channel excitation. Method: Structure of coil is birdcage type with twelve longitudinal elements generating a sufficiently homogeneous electromagnetic field B1 in the coil. From commonly constructed birdcage coils, this is distinguished by the possibility of changing the resonant frequency over a large frequency range (including f019F = 188.6 MHz - f01H = 200.4 MHz @ B0 4.7T), which is allowed possible by changing the electrical capacitance between the wires through changes in the length of the coil. Result: The quality factors in the resonances for the unloaded coil are Q1H = 328 and Q19F = 331. This is comparable to the common type of birdcage coil design used for only one of the frequencies. However, the presented coil allows measurement of 1H, as well as 19F images with comparable MR signals, but without the need to change the coils between individual measurements. Conclusion: Both such measurements can thus be performed with an identical rodent position.
- Klíčová slova
- objemová radiofrekvenční cívka,
- MeSH
- design vybavení MeSH
- hlodavci MeSH
- magnetická rezonanční tomografie * přístrojové vybavení MeSH
- zobrazování fluorovou magnetickou rezonancí MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- klinická studie MeSH
- práce podpořená grantem MeSH
