Quantitative MRI of the liver: Evaluation of extracellular volume fraction and other quantitative parameters in comparison to MR elastography for the assessment of hepatopathy.

BACKGROUND: Chronic liver diseases pose a major health problem worldwide, while common tests for diagnosis and monitoring of diffuse hepatopathy have considerable limitations. Preliminary data on the quantification of hepatic extracellular volume fraction (ECV) with magnetic resonance imaging (MRI) for non-invasive assessment of liver fibrosis are encouraging, with ECV having the potential to overcome several of these constraints. PURPOSE: To clinically evaluate ECV provided by quantitative MRI for assessing the severity of liver disease. MATERIALS AND METHODS: In this prospective study, multiparametric liver MRI, including T1 mapping and magnetic resonance elastography (MRE), was performed in subjects with and without hepatopathy between November 2018 and October 2019. T1, T2, T2*, proton density fat fraction and stiffness were extracted from parametric maps by regions of interest and ECV was calculated from T1 relaxometries. Serum markers of liver disease were obtained by clinical database research. For correlation analysis, Spearman rank correlation was used. ROC analysis of serum markers and quantitative MRI data for discrimination of liver cirrhosis was performed with MRE as reference standard. RESULTS: 109 participants were enrolled (50.7 ± 16.1 years, 61 men). ECV, T1 and MRE correlated significantly with almost all serum markers of liver disease, with ECV showing the strongest associations (up to r = 0.67 with MELD, p < 0.01). ECV and T1 correlated with MRE (0.75 and 0.73, p < 0.01 each). ECV (AUC 0.89, cutoff 32.2%, sensitivity 85%, specificity 87%) and T1 mapping (AUC 0.85, cutoff 592.5 ms, sensitivity 83%, specificity 75%) featured good performances in detection of liver cirrhosis with only ECV performing significantly superior to model of end stage liver disease (MELD), AST/ALT ratio and international normalized ratio (p < 0.01, respectively). CONCLUSION: Quantification of hepatic extracellular volume fraction with MRI is suitable for estimating the severity of liver disease when using MRE as the standard of reference. It represents a promising tool for non-invasive assessment of liver fibrosis and cirrhosis.

[Magnetic-resonance imaging under degenerative changes in lumbar spine: state of the art]. / Magnitno-rezonansnaia tomografiia pri degenerativnykh izmeneniiakh poiasnichnogo otdela pozvonochnika: sovremennoe sostoianie voprosa.

Magnetic resonance imaging (MRI) of lumbar spine is a very frequent examination in any computer tomography unit. However, there are still no scan standards or standards for scan interpretation in the world's medical community. In this article based on our experience we describe common problems encountered by a radiologist during MRI examination of lumbar spine and its subsequent description. The literature survey and analysis are presented with a summary of current recommendations. We examined routine sequences, which could be included in MRI protocol, discussed common terminology, and showed the incidence of different pathologies. The special emphasis is made on assessing lumbar canal stenosis. In this article we focus on qualitative and quantitative criteria of lumbar spinal stenosis.

[Use of phase-contrast magnetic resonance imaging to quantify cerebrospinal fluid dynamics in patients with communicating hydrocephalus].

OBJECTIVE: to determine differences in cerebrospinal fluid (CSF) flow velocities in patients with varying degrees of communicating hydrocephalus (CH) versus a group of healthy volunteers without hydrodynamic disorders. MATERIAL AND METHODS: The investigation enrolled 27 CH patients (17 and 10 patients with an Evans index of 0.31 and 0.46, respectively) and 62 healthy volunteers. Average, volumetric, and peak flow velocities were determined at different intracranial levels. RESULTS: Analysis of differences between the mean values indicated that the patients with CH were observed to have progressive cranial cavity CSF outflow obstruction that depended on the degree of dilation of the ventricular system and, probably, on impaired CSF reabsorption. These changes can provide an explanation for the clinical symptoms present in the patients and also serve as diagnostic criteria. CONCLUSION: The investigation showed that phase-contrast magnetic resonance imaging might be used to estimate the quantitative indicators of CSF in health and in varying degrees of CH. The velocity characteristics of antegrade and retrograde CSF flows are significantly different in health and in disease, which may be relevant to neurologists and neurosurgeons when planning therapy and surgery options.

Evaluation of the flow of cerebrospinal fluid as well as gender and age characteristics in patients with communicating hydrocephalus, using phase-contrast magnetic resonance imaging.

To determine the difference in the velocity parameters of cerebrospinal fluid flow in patients with varying severity of communicating hydrocephalus compared to a group of healthy volunteers without hydrodynamic disorders. The study involved 35 subjects with communicating hydrocephalus (25 subjects with Evans index of 0.31; 10 subject with Evans index of 0.46) and 62 healthy volunteers. The mean, volume, and peak flow velocities were determined at the different intracranial levels. Also were made an assessment of gender and age differences. Analysis of the differences between the mean values showed the progressive inhibition of cerebrospinal fluid outflow from the cranial cavity [in moderate communicating hydrocephalus-at 1.5 times (p < 0.05), in severe communicating hydrocephalus at 2-2.5 times (p < 0.01)], depending on the severity of enlargement of the ventricular system and, most likely, related to inhibition of its reabsorption. These changes may explain the clinical symptoms of subjects and serve as diagnostic criteria. Also it was revealed a significant influence of the factor of age on speed characteristics of the cerebrospinal fluid flow (F = 5.3303, p = 0.0003, for mean velocity).