Decomposition Of Fat Research Articles

Assessment and integration of multiparametric MRI for liver fibrosis staging in rat non-alcoholic steatohepatitis: Evaluation of diagnostic efficiency and model interpretation

ObjectivesMulti-parametric MRI techniques, including intravoxel incoherence motion (IVIM), iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL IQ), T2* mapping and T2 mapping, were employed to develop and validate a predictive model for non-alcoholic steatohepatitis (NASH) diagnosis and liver fibrosis (LF) staging in rats. The combined model was interpreted using SHapley Additive exPlanations (SHAP) values for model understanding. Materials and methods160 healthy Sprague-Dawley (SD) rats were divided into control (n = 24) and experimental (n = 136) groups, and the 12-week and 16-week groups were injected intraperitoneally with carbon tetrachloride (CCl4) for 4 weeks, one month before the final feeding period. All rats were subjected to pathological examination to determine LF stage. Upon the study’s completion, 147 SD rats were assessed for liver fibrosis. Results84 SD rats were diagnosed with NASH and 31, 10, and 43 rats were histologically diagnosed with no fibrosis (F0), early LF (F1-F2), and late LF (F3-F4). For diagnosis of NASH and staging of liver fibrosis associated with NASH, a combined multi-parameter magnetic resonance imaging prediction model has a higher area under the ROC curve (AUC) than individual diffusion parameters, especially in advanced stages of fibrosis, with an AUC of 0.929 for the combined model. In SHAP, the free fluid(FF) value contributes most to the model for diagnosing NASH and advanced liver fibrosis, while the T2 value contributes most for diagnosing liver fibrosis and the apparent diffusion coefficient (ADC) value contributes most for diagnosing liver cirrhosis. ConclusionsThe integration of several magnetic resonance imaging methods along with SHAP value analysis provides a more comprehensive and theoretical investigation into the mechanisms and factors contributing to the progression of liver fibrosis in NASH, offering insights from various angles.

Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) for evaluation of early bone mass changes in ageing osteoporosis patients

This study explored the application value of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) technology in the early diagnosis of ageing osteoporosis (OP). 172 participants were enrolled and underwent magnetic resonance imaging (MRI) examinations on a 3.0T scanner. 100 cases were included in the normal group (50 males and 50 females; mean age: 45 years; age range: 20–84 years). 33 cases were included in the osteopenia group (17 males and 16 females; mean age: 55 years; age range: 43–83 years). 39 cases were included in the OP group (19 males and 20 females; mean age: 58 years; age range: 48–82 years). Conventional T1WI and T2WI were first obtained, followed by 3D-IDEAL-IQ-acquisition. Fat fraction (FF) and apparent transverse relaxation rate (R2*) results were automatically calculated from IDEAL-IQ-images on the console. Based on T1W and T2W-images, 300 ROIs for each participant were manually delineated in L1-L5 vertebral bodies of five middle slices. In each age group of all normal subjects, each parameter was significantly correlated with gender. In male participants from the normal, osteopenia, and OP groups, statistical analysis revealed F values of 11319.292 and 180.130 for comparisons involving FF and R2* values, respectively (all p<0.0001). The sensitivity and specificity of FF values were 0.906 and 0.950, 0.994 and 0.997, 0.865 and 0.820, respectively. For R2*, they were 0.665 and 0.616, 0.563 and 0.519, 0.571 and 0.368, respectively. In female participants from the normal, osteopenia, and OP-groups, statistical analysis revealed F values of 12461.658 and 548.274 for comparisons involving FF and R2* values, respectively (all p<0.0001). The sensitivity and specificity of FF values were 0.985 and 0.991, 0.996 and 0.996, 0.581 and 0.678, respectively. For R2*, they were 0.698 and 0.730, 0.603 and 0.665, 0.622 and 0.525, respectively. Significant differences were indicated in the quantitative values among the three groups. FF value had good performance, while R2* value had poor performance in discriminating osteopenia and OP-groups. Overall, the IDEAL-IQ technique offers specific reference indices that enable noninvasive and quantitative assessment of lumbar vertebrae bone metabolism, thereby providing diagnostic information for OP.

Quantitative assessment of renal steatosis in patients with type 2 diabetes mellitus using the iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence imaging: repeatability and clinical implications.

Fatty kidney disease is linked to renal function damage, but there is no noninvasive tool for monitoring renal fat accumulation. This study aimed to explore the repeatability of the iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification (IDEAL-IQ) sequence imaging in quantifying renal fat deposition and to assess the differences observed in patients with type 2 diabetes mellitus (T2DM). A total of 26 healthy participants underwent two IDEAL-IQ scans without repositioning, and the repeatability of the imaging technique was assessed with Bland-Altman analysis. Additionally, 96 patients with T2DM underwent a single IDEAL-IQ scan for the examination of renal fat deposition. The patients with T2DM were classified into three groups based on their estimated glomerular filtration rate (eGFR). One-way analysis of variance was used to analyze the differences of renal fat depositions between the groups. Receiver operating characteristic curve analysis was used to assess the diagnostic performance of IDEAL-IQ. Bland-Altman analyses showed narrower limits of agreement and a significant correlation (r=0.81; P<0.05) between the two IDEAL-IQ scans. Statistically significant differences between the healthy volunteers and patients with T2DM, diabetic kidney disease (DKD) I-II, and or DKD III-IV were found in renal parenchymal proton-density fat fraction (PDFF) values (P<0.001). Renal parenchymal PDFF was negatively correlated with eGFR (r=-0.437; P<0.001) and positive correlated with serum creatinine level (µmol/L) (r=0.421; P<0.001). The area under the curve of IDEAL-IQ in discriminating between the healthy volunteers and patients with T2DM was 0.857. For discriminating T2DM from DKD I-II and DKD III-IV, the IDEAL-IQ had an area under the curve of 0.689 and 0.823, respectively. IDEAL-IQ is a promising and reproducible technique for the assessment of renal fat deposition and identification of risk of DKD in patients with T2DM. Moreover, IDEAL-IQ imaging is expected to improve the sensitivity and specificity of early renal function damage and staging assessment of patients with T2DM.

Quantitative assessment of rotator cuff injuries using synthetic MRI and IDEAL-IQ imaging techniques

PurposeTo evaluate synthetic magnetic resonance imaging (SyMRI) and iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL-IQ) imaging for a comprehensive evaluation of rotator cuff injuries (RCI). MethodsNinety-seven patients with RCI were classified into four groups based on the arthroscopic results: (grade II), partial tear (grade III), complete tear (grade IV), and controls (grade I). T1 (Transverse Relaxation Time 1), T2 (Transverse Relaxation Time 2), proton density (PD), and fat fraction (FF) were evaluated using SyMRI and IDEAL-IQ. Measurement reliability was assessed using intraclass correlation coefficients (ICC). The diagnostic potential for grading RCI was evaluated using ordinal regression and ROC analyses. ResultsA high measurement reliability (ICC > 0.7) was observed across subregions. T1 and T2 significantly varied across grades, particularly T2 in the lateral subregion between grades III and IV (P < 0.001) and the central subregion between grades II and III (P < 0.001). ROC analyses yielded valuable diagnostic accuracy, including T2 in the lateral subregion with an AUC of 0.891, distinguishing grade I from grade IV. Positive correlations were found between T2 values in specific shoulder subregions and injury grade (r = 0.615 for lateral, r = 0.542 for medial, both P < 0.001). In grade IV, FF was notably increased in the supraspinatus, infraspinatus, and subscapularis muscles compared with grades I-III. There were no significant FF variations in the teres minor muscle among grades. ConclusionsQuantitative MRI parameters from SyMRI and IDEAL-IQ, especially T2 and FF, may classify and assess RCI severity. The results could help improve the accuracy of diagnosing different grades of RCI, offering clinicians additional tools for improving patient outcomes through personalized medicine.

Vertebral bone quality score was associated with paraspinal muscles fat infiltration, but not modic classification in patients with chronic low back pain: a prospective cross-sectional study

BackgroundThe lumbar vertebra and paraspinal muscles play an important role in maintaining the stability of the lumbar spine. Therefore, the aim of this study was to investigate the relationship between paraspinal muscles fat infiltration and vertebral body related changes [vertebral bone quality (VBQ) score and Modic changes (MCs)] in patients with chronic low back pain (CLBP).MethodsPatients with CLBP were prospectively collected in four hospitals and all patients underwent 3.0T magnetic resonance scanning. Basic clinical information was collected, including age, sex, course of disease (COD), and body mass index (BMI). MCs were divided into 3 types based on their signal intensity on T1 and T2-weighted imaging. VBQ was obtained by midsagittal T1-weighted imaging (T1WI) and calculated using the formula: SIL1−4/SICSF. The Proton density fat fraction (PDFF) values and cross-sectional area (CSA) of paraspinal muscles were measured on the fat fraction map from the iterative decomposition of water and fat with the echo asymmetry and least-squares estimation quantitation (IDEAL-IQ) sequences and in/out phase images at the central level of the L4/5 and L5/S1 discs.ResultsThis study included 476 patients with CLBP, including 189 males and 287 females. 69% had no Modic changes and 31% had Modic changes. There was no difference in CSA and PDFF for multifidus(MF) and erector spinae (ES) at both levels between Modic type I and type II, all P values>0.05. Spearman correlation analysis showed that VBQ was weakly negatively correlated with paraspinal muscles CSA (all r values < 0.3 and all p values < 0.05), moderately positive correlation with PDFF of MF at L4/5 level (r values = 0.304, p values<0.001) and weakly positively correlated with PDFF of other muscles (all r values<0.3 and all p values<0.001). Multivariate linear regression analysis showed that age (β = 0.141, p < 0.001), gender (β = 4.285, p < 0.001) and VBQ (β = 1.310, p = 0.001) were related to the total PDFF of muscles. For MCs, binary logistic regression showed that the odds ratio values of age, BMI and COD were 1.092, 1.082 and 1.004, respectively (all p values ＜ 0.05).ConclusionsPDFF of paraspinal muscles was not associated with Modic classification. In addition to age and gender, PDFF of paraspinal muscles is also affected by VBQ. Age and BMI are considered risk factors for the MCs in CLBP patients.

IDEAL-IQ combined with intravoxel incoherent motion diffusion-weighted imaging for quantitative diagnosis of osteoporosis

BackgroundOsteoporosis (OP) is a common chronic metabolic bone disease characterized by decreased bone mineral content and microstructural damage, leading to increased fracture risk. Traditional methods for measuring bone density have limitations in accurately distinguishing vertebral bodies and are influenced by vertebral degeneration and surrounding tissues. Therefore, novel methods are needed to quantitatively assess changes in bone density and improve the accurate diagnosis of OP.MethodsThis study aimed to explore the applicative value of the iterative decomposition of water and fat with echo asymmetry and least-squares estimation-iron (IDEAL-IQ) sequence combined with intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for the diagnosis of osteoporosis. Data from 135 patients undergoing dual-energy X-ray absorptiometry (DXA), IDEAL-IQ, and IVIM-DWI were prospectively collected and analyzed. Various parameters obtained from IVIM-DWI and IDEAL-IQ sequences were compared, and their diagnostic efficacy was evaluated.ResultsStatistically significant differences were observed among the three groups for FF, R2*, f, D, DDC values, and BMD values. FF and f values exhibited negative correlations with BMD values, with r=-0.313 and − 0.274, respectively, while R2*, D, and DDC values showed positive correlations with BMD values, with r = 0.327, 0.532, and 0.390, respectively. Among these parameters, D demonstrated the highest diagnostic efficacy for osteoporosis (AUC = 0.826), followed by FF (AUC = 0.713). D* exhibited the lowest diagnostic performance for distinguishing the osteoporosis group from the other two groups. Only D showed a significant difference between genders. The AUCs for IDEAL-IQ, IVIM-DWI, and their combination were 0.74, 0.89, and 0.90, respectively.ConclusionsIDEAL-IQ combined with IVIM-DWI provides valuable information for the diagnosis of osteoporosis and offers evidence for clinical decisions. The superior diagnostic performance of IVIM-DWI, particularly the D value, suggests its potential as a more sensitive and accurate method for diagnosing osteoporosis compared to IDEAL-IQ. These findings underscore the importance of integrating advanced imaging techniques into clinical practice for improved osteoporosis management and highlight the need for further research to explore the full clinical implications of these imaging modalities.

Moderate resistance training reduces intermuscular adipose tissue and risk factors of atherosclerotic cardiovascular disease for elderly patients with type 2 diabetes.

This study aimed to assess the impact of moderate resistance training on intermuscular adipose tissue (IMAT) in elderly patients with type 2 diabetes and the independent effect of IMAT reduction on metabolic outcomes. In this randomized controlled trial, 85 patients with type 2 diabetes were assigned to either the resistance training group (42 participants) or the control group (43 participants) for a 6-month intervention. The primary outcome was changes in IMAT measured by computed tomography scan and magnetic resonance imaging using the interactive decomposition of water and fat with echo asymmetry and least squares qualification sequence. Secondary outcomes included changes in metabolic parameters. Thirty-seven participants in each group completed the study. The IMAT area (measured by a computed tomography scan) in the resistance group decreased from 5.176 ± 1.249 cm2 to 4.660 ± 1.147 cm2, which is a change of -0.512 ± 0.115 cm2, representing a 9.89% decrease from the least-squares adjusted mean at baseline, which was significantly different from that of the control group (a change of 0.587 ± 0.115 cm2, a 10.34% increase). The normal attenuation muscle area (representing normal muscle density) in the resistance group increased from 82.113 ± 8.776 cm2 to 83.054 ± 8.761 cm2, a change of 1.049 ± 0.416 cm2, a 1.3% increase, which was significantly different from that of the control group (a change of -1.113 ± 0.416 cm2, a 1.41% decrease). Homeostasis model assessment 2 of beta cell function (HOMA2-β; increased from 52.291 ± 24.765 to 56.368 ± 21.630, a change of 4.135 ± 1.910, a 7.91% increase from baseline) and ratio of insulin increase to blood glucose increase at 30 min after the oral glucose tolerance test (∆I30/∆G30; increased from 4.616 ± 1.653 to 5.302 ± 2.264, a change of 0.715 ± 0.262, a 15.49% increase) in the resistance group were significantly improved compared with those in the control group, which had a change of -3.457 ± 1.910, a 6.05% decrease in HOMA2-β, and a change of -0.195 ± 0.262, a 3.87% decrease in ∆I30/∆G30, respectively. Adjusting for sex, age, diabetes duration, baseline IMAT, and the dependent variable at baseline, linear regression showed that the change in IMAT area was not related to the change in HOMA2 insulin resistance (β = -0.178, p = .402) or the change in HOMA2-β (β = -1.891, p = .197), but was significantly related to the changes in ∆I30/∆G30 (β = -0.439, p = .047), 2-h postprandial glucose (β = 1.321, p = .026), diastolic blood pressure (β = 2.425, p = .018), normal attenuation muscle area (β = -0.907, p = .019) and 10-year risk of atherosclerotic cardiovascular disease (β = 0.976, p = .002). Low-level, moderate resistance training reduces IMAT content. Even a small reduction in IMAT may be related to a decrease in risk factors for atherosclerotic cardiovascular disease, but this small reduction may not be sufficient to reduce insulin resistance.

Automated evaluation of hip abductor muscle quality and size in hip osteoarthritis: Localized muscle regions are strongly associated with overall muscle quality

Limited information exists regarding abductor muscle quality variation across its length and which locations are most representative of overall muscle quality. This is exacerbated by time-intensive processes for manual muscle segmentation, which limits feasibility of large cohort analyses. The purpose of this study was to develop an automated and localized analysis pipeline that accurately estimates hip abductor muscle quality and size in individuals with mild-to-moderate hip osteoarthritis (OA) and identifies regions of each muscle which provide best estimates of overall muscle quality.Forty-four participants (age 52.7 ± 16.1 years, BMI 23.7 ± 3.4 kg/m2, 14 males) with and without mild-to-moderate radiographic hip OA were recruited for this study. Unilateral hip magnetic resonance (MR) images were acquired on a 3.0 T MR scanner and included axial T1-weighted fast spin echo and 3D axial Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL-IQ) spoiled gradient-recalled echo (SPGR) with multi-peak fat spectrum modeling and single T2* correction. A three dimensional (3D) V-Net convolutional neural network was trained to automatically segment the gluteus medius (GMED), gluteus minimus (GMIN), and tensor fascia lata (TFL) on axial IDEAL-IQ. Agreement between manual and automatic segmentation and associations between axial fat fraction (FF) estimated from IDEAL-IQ and overall muscle FF were evaluated.Dice scores for automatic segmentation were 0.94, 0.87, and 0.91 for GMED, GMIN, and TFL, respectively. GMED, GMIN, and TFL volumetric and FF measures were strongly correlated (r: 0.92–0.99) between automatic and manual segmentations, where all values fell within the 95% limits of agreement of [−9.79 cm3, 17.43 cm3] and [−1.99%, 2.89%], respectively. Axial FF was significantly associated with overall FF with the strongest correlations at 50%, 50%, and 65% the length of the GMED, GMIN, and TFL muscles, respectively (r: 0.93–0.97). An automated and localized analysis can provide efficient and accurate estimates of hip abductor muscle quality and size across muscle length. Specific regions of the muscle may be used to estimate overall muscle quality in an abbreviated evaluation of muscle quality.

Understanding ADC variation by fat content effect using a dual-function MRI phantom

BackgroundA dual-function phantom designed to quantify the apparent diffusion coefficient (ADC) in different fat contents (FCs) and glass bead densities (GBDs) to simulate the human tissues has not been documented yet. We propose a dual-function phantom to quantify the FC and to measure the ADC at different FCs and different GBDs.MethodsA fat-containing diffusion phantom comprised by 30 glass-bead-containing fat-water emulsions consisting of six different FCs (0, 10, 20, 30, 40, and 50%) multiplied by five different GBDs (0, 0.1, 0.25, 0.5, and 1.0 g/50 mL). The FC and ADC were measured by the “iterative decomposition of water and fat with echo asymmetry and least squares estimation-IQ,” IDEAL-IQ, and single-shot echo-planar diffusion-weighted imaging, SS-EP-DWI, sequences, respectively. Linear regression analysis was used to evaluate the relationship among the fat fraction (FF) measured by IDEAL-IQ, GBD, and ADC.ResultsThe ADC was significantly, negatively, and linearly associated with the FF (the linear slope ranged from -0.005 to -0.017, R2 = 0.925 to 0.986, all p < 0.001). The slope of the linear relationship between the ADC and the FF, however, varied among different GBDs (the higher the GBD, the lower the slope). ADCs among emulsions across different GBDs and FFs were overlapped. Emulsions with low GBDs plus high FFs shared a same lower ADC range with those with median or high GBDs plus median or lower FFs.ConclusionsA novel dual-function phantom simulating the human tissues allowed to quantify the influence of FC and GBD on ADC.Relevance statementThe study developed an innovative dual-function MRI phantom to explore the impact of FC on ADC variation that can affect clinical results. The results revealed the superimposed effect on FF and GBD density on ADC measurements.Key points• A dual-function phantom made of glass bead density (GBD) and fat fraction (FF) emulsion has been developed.• Apparent diffusion coefficient (ADC) values are determined by GBD and FF.• The dual-function phantom showed the mutual ADC addition between FF and GBD.Graphical

Persistent Organic Pollutants released from decomposed adipose tissue affect mitochondrial enzyme function in the brain and eyes other than the liver.

Persistent organic pollutants (POPs) are toxic chemicals that can accumulate in the human body, and particularly in adipose tissue. POPs can induce metabolic diseases via mitochondrial dysfunction and can also cause cancer, obesity, and cardiovascular and neurodegenerative diseases. Although the effects of POPs were studied by evaluating mitochondrial function, which is fundamental in investigating the etiologies of various metabolic diseases, the physiological impact of POPs released by the decomposition of fat in adipose tissue is barely understood. Therefore, to investigate the mitochondrial dysfunction caused by POPs released from adipose tissue to other organs, zebrafish were exposed to POPs and placed into four groups: control (C), obesity control (OC), obesity control with POPs (OP), and POP exposure with obesity and caloric restriction (OPR). Next, the activities of the mitochondrial respiratory complexes and the levels of ATP production, reactive oxygen species/reactive nitrogen species (ROS/RNS), and antioxidants, such as glutathione and superoxide dismutase, were measured in the brain, eyes, and liver, as these are the major organs most susceptible to metabolic diseases. POPs released from adipose tissue showed a stronger effect than the direct effects of obesity and POPs on mitochondrial enzyme activity in the brain and eye. Released POPs increased mitochondrial complex I activity and decreased mitochondrial complex II activity compared with normal, obesity, and POP-treated conditions in the brain and eyes. However, the mitochondrial complexes' activities in the liver were affected more by obesity and POPs. In the liver, the mitochondrial enzyme activities of the OPR group seemed to recover to the control level, but it was slightly lowered in the OC and OP groups. Independently, the ROS/RNS and antioxidant levels were not affected by obesity, POPs, or the released POPs in the brain, eye, and liver. The results indicate that POPs stored in adipose tissue and released during fat decomposition did not affect oxidative stress but could affect mitochondrial respiratory enzymes in organ dependent manner. This study is meaningful in that it provides experimental evidence that stored POPs affect specific organs for prolonged periods and can be linked to various diseases in advance.

Peritumoral Fat Content Identified Using Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-squares Estimation (IDEAL) Correlates with Breast Cancer Prognosis.

Adipocytes around aggressive breast cancer (BC) are less lipid different from naive adipocytes (cancer-associated adipocytes, CAAs), and peritumoral edema caused by the release of cytokines from CAAs can conduce to decrease the peritumoral fat proportion. The purpose of this study was to correlate peritumoral fat content identified by using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) with lymph node metastasis (LNM) and recurrence-free survival (RFS) in BC patients and to compare with T2-weighted (T2WI) and diffusion-weighted images (DWI) analyses. This retrospective study consisted of 85 patients who were diagnosed with invasive carcinoma of breast and underwent breast MRI, including IDEAL before surgery. The scan time of fat fraction (FF) map imaging using IDEAL was 33s. Four regions of interest (ROIs), which are 5 mm from the tumor edge, and one ROI in the mammary fat of the healthy side were set on the FF map. Then average peritumoral FF values (TFF), average FF values on the healthy side (HFF), and peritumoral fat ratio (PTFR, which is defined as TFF/HFF) were calculated. Tumor apparent diffusion coefficient (ADC) values were measured on ADC map obtained by DWI. Peritumoral edema was classified into three grades based on the degree of signal intensity around the tumor on T2WI (T2 edema). The results of stepwise logistic regression analysis for four variables (TFF, PTFR, T2 edema, and ADC value) indicated that TFF and T2 edema were significant factors of LNM (p < 0.01). RFS was significantly associated with TFF (p = 0.016), and 47 of 49 (95.9%) patients with TFF more than 85.5% were alive without recurrence. Peritumoral fat content identified by using IDEAL is associated with LNM and RFS and may therefore be a useful prognostic biomarker for BC.

Kidney R2* Mapping for Noninvasive Evaluation of Iron Overload in Paroxysmal Nocturnal Hemoglobinuria.

The kidney iron deposition can cause kidney damage and renal insufficiency in paroxysmal nocturnal hemoglobinuria (PNH) patients. Assessment of iron deposition in the kidney is essential for the early diagnosis of renal damage in PNH patients. The purpose of this study was to evaluate kidney R2* (T2* reciprocals) values in PNH patients using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ). Two radiologists measured the R2* values of the renal cortex in 14 PNH patients and 13 healthy volunteers using IDEAL-IQ. Lactate dehydrogenase (LDH), a reliable marker of intravascular hemolysis, was also measured in all participants. The kidney R2* values were significantly higher in PNH patients compared with those in healthy volunteers (P < 0.001). High inter-operator reproducibility of the measurements was also acquired using IDEAL-IQ. LDH levels were also significantly higher in PNH patients compared with those in healthy volunteers (P < 0.001). Kidney R2* values strongly correlated with LDH levels in PNH patients. IDEAL-IQ has a possibility of becoming a useful method for the noninvasive evaluation of renal iron overload in PNH patients.

The quantitative parameters derived from IDEAL-IQ in the lumbar vertebrae of healthy children: a pilot study of bone development.

Early childhood bone development affects that of bone disease in adolescence and adulthood. Many diseases can affect the cancellous bone or bone marrow. Therefore, it is of great significance to quantify the bone development of healthy children. The evaluation methods of bone development include bone age (BA) assessment and dual-energy X-ray bone mineral densitometry (DXA), both of which have strong subjectivity. The present study was conducted to improve our understanding of the bone development of healthy children using the quantitative parameters derived from iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification (IDEAL-IQ) sequence. Our study enrolled healthy children between January 2022 to December 2022 consecutively in Children's Hospital of Shanxi. The inclusion criteria were as follows: (I) age ≤18 years; (II) no contraindications (surgical and interventional devices for ferromagnetic materials, cardiac implantable electronic devices, cochlear implants, insulin pumps, dental implants containing metal or alloy) to magnetic resonance imaging (MRI) scan. The exclusion criteria were as follows: (I) previous malignant disease, (II) previous chemoradiotherapy, (III) previous spine surgery, (IV) previous or acute vertebral compression fracture, (V) artifacts present in images. Participants underwent MRI scans using IDEAL-IQ sequence in the lumbar vertebrae. The IDEAL-IQ parameters [proton density fat fraction (PDFF), 1/T2* (R2*)] were obtained. The factor analysis of variance was applied to compare the differences of PDFF and R2* in different lumbar vertebral groups. The Kruskal-Wallis H test or Mann-Whitney U test was applied to compare the differences of quantitative data among different gender or age groups. Spearman correlation analysis was applied to study the relationship among the age, PDFF, and R2*. A total of 145 participants (76 males, 69 females) were evaluated. There were no significant differences in PDFF and R2* of different lumbar vertebrae (PPDFF=0.338, PR2*=0.868). The average age was 36 [13-72] months. They were assigned into 4 groups (0-11, 12-35, 36-71, and 72-144 months). As the age increased, the average PDFF and R2* both increased significantly (rPDFF=0.659, rR2*=0.359, P<0.001). There were significant statistical differences in PDFF and R2* between the 4 age groups (ZPDFF=46.651, ZR2*=27.537, P<0.001). Moreover, the PDFF was also positively correlated with R2* (r=0.576, P<0.001). No association was found between the gender and PDFF, R2* (PPDFF=0.949, PR2*=0.177). The quantitative parameters derived from IDEAL-IQ in the lumbar vertebrae of healthy children will improve our understanding of bone development and provide a basis for further exploring the diseases that affect children's bone development.

Rectus Femoris Ultrasound Echo Intensity Is a Valid Estimate of Percent Intramuscular Fat in Patients Following Anterior Cruciate Ligament Reconstruction.

The aim of the work described here was to evaluate quadriceps muscle ultrasound metrics and common demographic variables to create a conversion equation that validly predicts magnetic resonance imaging (MRI) percent intramuscular fat after anterior cruciate ligament reconstruction (ACLR). We recruited 15 participants between the ages of 18 and 35 y who were 1-5 y post-ACLR. For the MRI assessment, we used an iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) sequence to assess the mid-thigh. A single reader manually segmented the rectus femoris on two consecutive MRI slices using ITK-Snap to estimate the percent intramuscular fat. For the ultrasound assessment, a single investigator captured transverse panoramic ultrasound images of the mid-thigh with the participant positioned supine and the knee flexed to 30°. A separate single reader used ImageJ to manually segment the rectus femoris ultrasound images. Ultrasound metrics included muscle cross-sectional area, echo intensity and subcutaneous fat thickness. A stepwise linear multiple regression was used to develop an equation to predict MRI percent intramuscular fat using the ultrasound metrics and common demographics (i.e., age, sex, height, mass). Additionally, intraclass correlation coefficients (ICC2,k) and Bland-Altman plots were used to assess the agreement between true and estimated percent intramuscular fat. Echo intensity and age significantly predicted MRI intramuscular fat percent (p=0.003, r2=0.62). When using the conversion equation, there was high agreement (ICC2,k=0.87, 95% confidence interval: 0.62-0.96) between the estimated and true percent intramuscular fat. Our patient population-specific conversion equation that uses quadriceps muscle ultrasound echo intensity and age is a valid estimate of MRI percent intramuscular fat.

Real-time water/fat imaging at 0.55T with spiral out-in-out-in sampling.

To develop an efficient and flexible water/fat separated real-time MRI (RT-MRI) method using spiral out-in-out-in (OIOI) sampling and balanced SSFP (bSSFP) at 0.55T. A bSSFP sequence with golden-angle spiral OIOI readout was developed, capturing three echoes to allow water/fat separation. A low-latency reconstruction that combines all echoes was available for online visualization. An offline reconstruction provided water and fat RT-MRI in two steps: (1) image reconstruction with spatiotemporally constrained reconstruction (STCR) and (2) water/fat separation with hierarchical iterative decomposition of water and fat with echo asymmetry and least-squares estimation (HIDEAL). In healthy volunteers, spiral OIOI was acquired in the wrist during a radial-to-ulnar deviation maneuver, in the heart without breath-hold and cardiac gating, and in the lower abdomen during free-breathing for visualizing small bowel motility. We demonstrate successful water/fat separated RT-MRI for all tested applications. In the wrist, resulting images provided clear depiction of ligament gaps and their interactions during the radial-to-ulnar deviation maneuver. In the heart, water/fat RT-MRI depicted epicardial fat, provided improved delineation of epicardial coronary arteries, and provided high blood-myocardial contrast for ventricular function assessment. In the abdomen, water-only RT-MRI captured small bowel mobility clearly with improved water-fat contrast. We have demonstrated a novel and flexible bSSFP spiral OIOI sequence at 0.55T that can provide water/fat separated RT-MRI with a variety of application-specific temporal resolution and spatial resolution requirements.

Quantitative ultrasound fatty liver evaluation in a pediatric population: comparison with magnetic resonance imaging of liver proton density fat fraction

BackgroundBiopsy remains the gold standard for the diagnosis of hepatic steatosis, the leading cause of pediatric chronic liver disease; however, its costs call for less invasive methods.ObjectiveThis study examined the diagnostic accuracy and reliability of quantitative ultrasound (QUS) for the assessment of liver fat content in a pediatric population, using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the reference standard.Materials and methodsWe enrolled 36 patients. MRI-PDFF involved a 3-dimensional T2*-weighted with Dixon pulse multiple-echo sequence using iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL IQ). QUS imaging relied on the ultrasound system “RS85 A” (Samsung Medison, Seoul, South Korea) and the following software: Hepato-Renal Index with automated region of interest recommendation (EzHRI), Tissue Attenuation Imaging (TAI), and Tissue Scatter Distribution Imaging (TSI). For each QUS index, receiver operating characteristic (ROC) curve analysis against MRI-PDFF was used to identify the associated cut-off value and the area under the ROC curve (AUROC). Concordance between two radiologists was assessed by intraclass correlation coefficients (ICCs) and Bland–Altman analysis.ResultsA total of 61.1% of the sample (n=22) displayed a MRI-PDFF ≥ 5.6%; QUS cut-off values were TAI=0.625 (AUROC 0.90, confidence interval [CI] 0.77–1.00), TSI=91.95 (AUROC 0.99, CI 0.98–1.00) and EzHRI=1.215 (AUROC 0.98, CI 0.94–1.00). Inter-rater reliability was good-to-excellent for EzHRI (ICC 0.91, 95% C.I. 0.82–0.95) and TAI (ICC 0.94, 95% C.I. 0.88–0.97) and moderate to good for TSI (ICC 0.73; 95% C.I. 0.53–0.85).ConclusionOur results suggest that QUS can be used to reliably assess the presence and degree of pediatric hepatic steatosis.Graphical abstract

Hepatic MR imaging using IDEAL-IQ sequence: Will Gd-EOB-DTPA interfere with reproductivity of fat fraction quantification?

Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence (IDEAL-IQ) is based on chemical shift-based water and fat separation technique to get proton density fat fraction. Multiple studies have shown that using IDEAL-IQ to test the stability and repeatability of liver fat is acceptable and has high accuracy. To explore whether Gadoxetate Disodium (Gd-EOB-DTPA) interferes with the measurement of the hepatic fat content quantified with the IDEAL-IQ and to evaluate the robustness of this technique. IDEAL-IQ was used to quantify the liver fat content at 3.0T in 65 patients injected with Gd-EOB-DTPA contrast. After injection, IDEAL-IQ was estimated four times, and the fat fraction (FF) and R2* were measured at the following time points: Pre-contrast, between the portal phase (70 s) and the late phase (180 s), the delayed phase (5 min) and the hepatobiliary phase (20 min). One-way repeated-measures analysis was conducted to evaluate the difference in the FFs between the four time points. Bland-Altman plots were adopted to assess the FF changes before and after injection of the contrast agent. P < 0.05 was considered statistically significant. The assessment of the FF at the four time points in the liver, spleen and spine showed no significant differences, and the measurements of hepatic FF yielded good consistency between T1 and T2 [95% confidence interval: -0.6768%, 0.6658%], T1 and T3 (-0.3900%, 0.3178%), and T1 and T4 (-0.3750%, 0.2825%). R2* of the liver, spleen and spine increased significantly after injection (P < 0.0001). Using the IDEAL-IQ sequence to measure the FF, we can obtain results that will not be affected by Gd-EOB-DTPA. The high reproducibility of the IDEAL-IQ sequence makes it available in the scanning interval to save time during multiphase examinations.

Fat fraction and R2 * values of various liver masses: Initial experience with 6-point Dixon method on a 3T MRI system

PurposeTo assess the feasibility of the 6-point Dixon method for evaluating liver masses. We also report our initial experience with the quantitative values in various liver masses on a 3T system. Materials and methodsOf 251 consecutive patients for whom 6-point Dixon was employed in abdominal magnetic resonance imaging scans between October 2020 and October 2021, 117 nodules in 117 patients with a mass diameter of more than 1 cm were included in the study. Images for measuring the proton density fat fraction (PDFF) and R2 * values were obtained using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation-quantitative technique for liver imaging. Two radiologists independently measured PDFF (%) and R2 * (Hz). Inter-reader agreement and the differences between readers were examined using intra-class correlation coefficient (ICC) and the Bland-Altman method, respectively. PDFF and R2 * values in differentiating liver masses were examined. ResultsThe masses included hepatocellular carcinoma (n = 59), cyst (n = 20), metastasis (n = 14), hemangioma (n = 8), and others (n = 16). The ICCs for the region of interest (mm2), PDFF, and R2 * were 0.988 (95 % confidence interval (CI): 0.983, 0.992), 0.964 (95 % CI: 0.949, 0.975), and 0.962 (95 % CI: 0.941, 0.975), respectively. The differences of measurements between the readers showed that 5.1 % (6/117) and 6.0% (7/117) for PDFF and R2 * , respectively, were outside the 95 % CI. ConclusionOur observation indicates that the 6-point Dixon method is applicable to liver masses.

Correlation analysis of quantitative MRI measurements of thigh muscles with histopathology in patients with idiopathic inflammatory myopathy

ObjectivesTo validate the correlation between histopathological findings and quantitative magnetic resonance imaging (qMRI) fat fraction (FF) and water T2 mapping in patients with idiopathic inflammatory myopathy (IIM).MethodsThe study included 13 patients with histopathologically confirmed IIM who underwent dedicated thigh qMRI scanning within 1 month before open muscle biopsy. For the biopsied muscles, FF derived from the iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation (IDEAL-IQ) and T2 time from T2 mapping with chemical shift selective fat saturation were measured using a machine learning software. Individual histochemical and immunohistochemical slides were evaluated using a 5-point Likert score. Inter-reader agreement and the correlation between qMRI markers and histopathological scores were analyzed.ResultsReaders showed good to perfect agreement in qMRI measurements and most histopathological scores. FF of the biopsied muscles was positively correlated with the amount of fat in histopathological slides (p = 0.031). Prolonged T2 time was associated with the degree of variation in myofiber size, inflammatory cell infiltration, and amount of connective tissues (p ≤ 0.008 for all).ConclusionsUsing the machine learning-based muscle segmentation method, a positive correlation was confirmed between qMRI biomarkers and histopathological findings of patients with IIM. This finding provides a basis for using qMRI as a non-invasive tool in the diagnostic workflow of IIM.Relevance statementBy using ML-based muscle segmentation, a correlation between qMRI biomarkers and histopathology was found in patients with IIM: qMRI is a potential non-invasive tool in this clinical setting.Key points• Quantitative magnetic resonance imaging measurements using machine learning-based muscle segmentation have good consistency and reproductivity.• Fat fraction of idiopathic inflammatory myopathy (IIM) correlated with the amount of fat at histopathology.• Prolonged T2 time was associated with muscle inflammation in IIM.Graphical

Association between IDEAL-IQ MRI fat fraction quantification and pelvic bone marrow reserve function in concurrent chemoradiotherapy for cervical cancer

ObjectiveTo analyze the association between iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantification sequence (IDEAL-IQ) magnetic resonance imaging (MRI) of bone marrow fat fraction and bone marrow reserve function during concurrent chemoradiotherapy for cervical cancer. MethodsThe study retrospectively analyzed twenty-six patients with stage IB1 to IVA cervical cancer treated between February 2020 and November 2020. All patients received concurrent chemoradiotherapy that included platinum alone or combined paclitaxel and platinum. Pelvic IDEAL-IQ MRI (plain and enhanced) was performed before and after treatment. Regions of interest, including the fifth lumbar vertebra, sacrum, ilium, ischium, and femoral neck, were manually delineated, and the bone marrow fat fraction was measured. Peripheral blood cell counts were recorded during treatment, and the relationship between the fat fraction values and changes in the blood cell counts was explored. ResultsIDEAL-IQ MRI bone marrow fat fraction was associated with platelet nadir and platelet decline during treatment. The average pelvic bone marrow fat fraction before chemoradiotherapy was moderately negatively correlated with platelet count nadir during concurrent chemoradiotherapy (r ​= ​−0.450, P ​= ​0.021). The change in average pelvic bone marrow fat fraction through chemoradiotherapy was moderately positively correlated with the degree of thrombocytopenia (r ​= ​0.399, P ​= ​0.044). ConclusionBone marrow fat content quantified by IDEAL-IQ was associated with platelet count nadir and the degree of thrombocytopenia in patients with cervical cancer undergoing concurrent chemoradiotherapy.