Postprandial splenic stiffness changes on magnetic resonance elastography in a young healthy population.

Magnetic resonance elastography (MRE) is an accurate noninvasive diagnostic tool for assessing the stiffness of parenchymal organs, including the spleen. However, this measurement may be biased due to postprandial changes in splenic stiffness. The aim of the current study was to evaluate postprandial changes in spleen stiffness assessed by MRE in a large sample of healthy volunteers. This was a prospective institutional research ethics board-approved study. Healthy volunteers with no history of liver disease were recruited for an MRE test and blood draw from December 2018 to July 2019. Each participant underwent spleen MRE after at least 4 h of fasting and again 30 min after a 1000 kcal meal. Also, 14 randomly selected volunteers underwent additional MRE examinations at 1.5 and 2.5 h after food intake. The MRE data were acquired at 60 Hz using a 1.5-T MRI scanner. The spleen stiffness was assessed using a weighted mean of stiffness values from regions of interest manually drawn on three to five spleen slices. Spearman's rank correlation, Wilcoxon signed-rank, Friedman, and Mann-Whitney tests were used for statistical analysis. A total of 100 volunteers met the inclusion criteria and were eventually enrolled in this study (age 23 ± 2 years; 65 women). The mean spleen stiffness for the whole group increased by 7.9% (p < 0.001) from the mean ± SD value of 5.09 ± 0.63 (95% CI: 4.96-5.21) kPa in the fasting state to 5.47 ± 0.66 (95% CI 5.34-5.60) kPa 30 min after the meal and then gradually decreased. However, even 2 h 30 min after the meal, the spleen stiffness was higher than in the fasting state. This difference was statistically significant at p less than 0.001. It was concluded that meal intake results in a statistically significant elevation of spleen stiffness that persists for 2.5 h. This finding supports the recommendation for routine fasting for more than 2.5 h prior to assessing MRE-based spleen stiffness.

3D vector MR elastography applications in small organs.

BACKGROUND: Magnetic resonance elastography (MRE) is a rapidly developing medical imaging technique that allows for quantitative assessment of the biomechanical properties of the tissue. MRE is now regarded as the most accurate noninvasive test for detecting and staging liver fibrosis. A two-dimensional (2D MRE) acquisition version is currently deployed at >2000 locations worldwide. 2D MRE allows for the evaluation of the magnitude of the complex shear modulus, also referred to as stiffness. The development of 3D vector MRE has enabled researchers to assess the biomechanical properties of small organs where wave propagation cannot be adequately analyzed with the 2D MRE imaging approach used in the liver. In 3D vector MRE, the shear waves are imaged and processed throughout a 3D volume and processed with an algorithm that accounts for wave propagation in any direction. Additionally, the motion is also imaged in x, y, and z directions at each voxel, allowing for more advanced processing to be applied. PURPOSE: This review describes the technical principles of 3D vector MRE, surveys its clinical applications in small organs, and discusses potential clinical significance of 3D vector MRE. CONCLUSION: 3D vector MRE is a promising tool for characterizing the biomechanical properties of small organs such as the uterus, pancreas, thyroid, prostate, and salivary glands. However, its potential has not yet been fully explored.

Evaluation of Spleen Stiffness in Young Healthy Volunteers Using Magnetic Resonance Elastography.

PURPOSE: Magnetic resonance elastography (MRE) has been established as the most accurate noninvasive technique for diagnosing liver fibrosis. Recent publications have suggested that the measurement of splenic stiffness is useful in setting where portal hypertension may be present. The goal of the current study was to compile normative data for MRE-assessed stiffness measurements of the spleen in young adults. MATERIALS AND METHODS: A total of 100 healthy young Caucasian volunteers (65 females and 35 males) in the age range of 20 to 32 years were enrolled in this study. The participants reported no history of chronic spleen and liver disease, normal alcohol consumption, and a normal diet. The MRE data were acquired by using a 1.5 T whole-body scanner and a 2D GRE pulse sequence with 60 Hz excitation. Spleen stiffness was calculated as a weighted mean of stiffness values in the regions of interest manually drawn by the radiologist on three to five spleen slices. RESULTS: Mean spleen stiffness was 5.09 ± 0.65 kPa for the whole group. Male volunteers had slightly higher splenic stiffness compared to females: 5.28 ± 0.78 vs. 4.98 ± 0.51 kPa, however, this difference was not statistically significant (p = 0.12). Spleen stiffness did not correlate with spleen fat content and liver stiffness but a statistically significant correlation with spleen volume was found. CONCLUSIONS: The findings of this study provide normative values for 2D MRE-based measurement of spleen stiffness in young adults, a basis for assessing the value of this biomarker in young patients with portal system pathologies.

Postprandial hepatic stiffness changes on magnetic resonance elastography in healthy volunteers.

Magnetic resonance elastography (MRE) is a reliable noninvasive method for assessment of hepatic stiffness. Liver stiffness is known to be affected by elevated postprandial portal blood flow in patients with chronic liver disease. The goal of this study was to determine whether food intake affects liver stiffness in the absence of known liver disease. We evaluated 100 volunteers (35 men and 65 women) who met inclusion criteria. The subjects had two MRE examinations, first while fasting and then 30 min after a test meal. Fourteen subjects also had two additional MRE exams 1 h 30 min and 2 h 30 min after the meal. Liver stiffness was measured by placing the largest possible polygon ROIs on the four widest liver slices and calculated as a mean of stiffness values from each slice. The correlation of liver stiffness values before and after the meal was assessed using a paired t-test. To evaluate the relationship between the change in postprandial liver stiffness and fasting liver stiffness values, linear regression was performed. The liver stiffness values in the fasting state ranged from 1.84 to 2.82 kPa, with a mean of 2.30 ± 0.23 kPa (95% CI 2.25-2.34). At 30 min after the meal, liver stiffness values ranged from 2.12 to 3.50 kPa, with a mean of 2.70 ± 0.28 kPa (95% CI 2.64-2.75), demonstrating a systematic postprandial increase by 0.40 ± 0.23 kPa (17.7 ± 3.5%). Meal intake significantly increases liver stiffness in healthy individuals, which persists for at least 2 h 30 min. Patients should fast for 3-4 h before MRE examinations to avoid fibrosis overstaging due to postprandial liver stiffness augmentation.

Value of liver iron concentration in healthy volunteers assessed by MRI.

Iron overload is a relatively common clinical condition resulting from disorders such as hereditary hemochromatosis, thalassemia, sickle cell disease, and myelodysplasia that can lead to progressive fibrosis and eventually cirrhosis of the liver. Therefore, it is essential to recognize the disease process at the earliest stage. Liver biopsy is the reference test for the assessment of liver fibrosis. It also allows for quantifying liver iron concentration (LIC) in patients. However, this is an invasive method with significant limitations and possible risks. Magnetic resonance imaging (MRI) and evaluation of the R2* relaxation rate can be an alternative to biopsy for assessing LIC. However, it causes a need for accurate R2* data corresponding to standard value for further comparison with examined patients. This study aimed to assess the normative values of liver R2* in healthy individuals. A total of 100 volunteers that met established criteria were enrolled in the study: 36 (36%) men and 64 (64%) women. The mean age was 22.9 years (range 20 to 32 years). R2* was estimated by an MRI exam with a 1.5 T clinical magnetic resonance scanner. Images for measuring the LIC and liver fat concentration were obtained using the IDEAL-IQ technique for liver imaging. The Mean (SD) liver R2* was 28.34 (2.25) s-1 (95% CI, 27.78-28.90, range 23.67-33.00 s-1) in females, 29.57 (3.20) s-1 (95% CI, 28.49-30.66, range 23.93-37.77 s-1) in males, and 28.72 (2.69) s-1 (range 23.67-37.77 s-1) in the whole group. R2* value in this particular population with a high proportion of young women did not exceed 38 s-1. In the absence of fibrosis or steatosis, liver stiffness and fat fraction did not show any relationship with R2*.

Publisher Correction: Classification of aggressive and classic mantle cell lymphomas using synchrotron Fourier Transform Infrared microspectroscopy.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Normative values for magnetic resonance elastography-based liver stiffness in a healthy population.

INTRODUCTION Chronic liver disease resulting in fibrosis, and ultimately cirrhosis, is a significant cause of morbidity and mortality worldwide. None of the conventional imaging techniques are able to detect early fibrosis and compare its grade with the histopathologic scale. Liver biopsy, as the diagnostic standard for liver fibrosis, also has limitations and is not well accepted by patients. Magnetic resonance elastography is a well­established technique for evaluating liver stiffness and may replace invasive procedures. Detection of liver fibrosis in its early stages, however, requires a detailed knowledge of normal liver stiffness. OBJECTIVES This study aimed to determine normal liver stiffness values in healthy volunteers. PATIENTS AND METHODS A total of 102 volunteers (mean age, 21.6 years; range, 20-28 years) with no history of gastrointestinal, hepatobiliary, or cardiovascular disease were enrolled in the study. Liver stiffness was evaluated by magnetic resonance elastography with a 1.5T clinical magnetic resonance scanner. Images of the induced transverse wave propagation were obtained and converted to tissue stiffness maps (elastograms). RESULTS The mean (SD) liver stiffness for the entire group of volunteers was 2.14 (0.28) kPa (range, 1.37-2.66 kPa). For women, the mean (SD) stiffness value was 2.14 (0.30) kPa (range, 1.37-2.66 kPa), and for men, 2.14 (0.25) kPa (range, 1.54-2.54 kPa). CONCLUSIONS Liver stiffness in a healthy adult cohort did not exceed 2.7 kPa and is not influenced by sex, body mass index, or fat content.

Classification of aggressive and classic mantle cell lymphomas using synchrotron Fourier Transform Infrared microspectroscopy.

Mantle cell lymphoma (MCL) is regarded as an incurable neoplasm, even to the novel drug strategies. It is known MCL has two morphological variants- classic and aggressive. Aggressive MCL is characterized by a higher mitotic index and proliferation rate, and poor overall survival in comparison to classic subtype. The insight into the detailed biochemical composition of MCL is crucial in the further development of diagnostic and treatment guidelines for MCL patients; therefore Synchrotron radiation Fourier Transform Infrared (S-FTIR) microspectroscopy combined with Principal Component Analysis (PCA) was used. The major spectral differences were observed in proteins and nucleic acids content, revealing a classification scheme of classic and aggressive MCLs. The results obtained suggest that FTIR microspectroscopy has reflected the histopathological discrimination of both MCL subtypes.