Fat Signal Research Articles

Accelerated liver water T1 mapping using single-shot continuous inversion-recovery spiral imaging.

Liver T1 mapping techniques typically require long breath holds or long scan time in free-breathing, need correction for inhomogeneities and process composite (water and fat) signals. The purpose of this work is to accelerate the multi-slice acquisition of liver water selective T1 (wT1) mapping in a single breath hold, improving the k-space sampling efficiency. The proposed continuous inversion-recovery (IR) Look-Locker methodology combines a single-shot gradient echo spiral readout, Dixon processing and a dictionary-based analysis for liver wT1 mapping at 3 T. The sequence parameters were adapted to obtain short scan times. The influence of fat, inhomogeneities and TE on the estimation of T1 was first assessed using simulations. The proposed method was then validated in a phantom and in 10 volunteers, comparing it with MRS and the modified Look-Locker inversion-recovery (MOLLI) method. Finally, the clinical feasibility was investigated by comparing wT1 maps with clinical scans in nine patients. The phantom results are in good agreement with MRS. The proposed method encodes the IR-curve for the liver wT1 estimation, is minimally sensitive to inhomogeneities and acquires one slice in 1.2 s. The volunteer results confirmed the multi-slice capability of the proposed method, acquiring nineslices in a breath hold of 11 s. The present work shows robustness to inhomogeneities ( , good repeatability ( and is in better agreement with MRS ( than is MOLLI ( . The wT1 maps in patients captured diverse lesions, thus showing their clinical feasibility. A single-shot spiral acquisition can be combined with a continuous IR Look-Locker method to perform rapid repeatable multi-slice liver water T1 mapping at a rate of 1.2 s per slice without a map. The proposed method is suitable for nine-slice liver clinical applications acquired in a single breath hold of 11 s.

STEAM-SASHA: a novel approach for blood- and fat-suppressed native T1 measurement in the right ventricular myocardium

ObjectiveThe excellent blood and fat suppression of stimulated echo acquisition mode (STEAM) can be combined with saturation recovery single-shot acquisition (SASHA) in a novel STEAM-SASHA sequence for right ventricular (RV) native T1 mapping.Materials and methodsSTEAM-SASHA splits magnetization preparation over two cardiac cycles, nulling blood signal and allowing fat signal to decay. Breath-hold T1 mapping was performed in a T1 phantom and twice in 10 volunteers using STEAM-SASHA and a modified Look-Locker sequence at peak systole at 3T. T1 was measured in 3 RV regions, the septum and left ventricle (LV).ResultsIn phantoms, MOLLI under-estimated while STEAM-SASHA over-estimated T1, on average by 3.0% and 7.0% respectively, although at typical 3T myocardial T1 (T1 > 1200 ms) STEAM-SASHA was more accurate. In volunteers, T1 was higher using STEAM-SASHA than MOLLI in the LV and septum (p = 0.03, p = 0.006, respectively), but lower in RV regions (p > 0.05). Inter-study, inter-observer and intra-observer coefficients of variation in all regions were < 15%. Blood suppression was excellent with STEAM-SASHA and noise floor effects were minimal.DiscussionSTEAM-SASHA provides accurate and reproducible T1 in the RV with excellent blood and fat suppression. STEAM-SASHA has potential to provide new insights into pathological changes in the RV in future studies.

Demonstration of magnetic resonance Z-spectral imaging for fatty acid characterization of bone marrow at 3 T.

Magnetic resonance Z-spectral imaging (ZSI) has emerged as a new approach to measure fat fraction (FF). However, its feasibility for fat spectral imaging remains to be elucidated. In this study, a single-slice ZSI sequence dedicated to fat spectral imaging was designed, and its capability for fatty acid characterization was investigated on peanut oil samples, a multiple-vial fat-water phantom with varied oil volumes, and vertebral body marrow in healthy volunteers and osteoporosis patients at 3 T. The peanut oil spectrum was also recorded with a 400-MHz NMR spectrometer. A Gaussian-Lorentzian sum model was used to resolve water and six fat signals of the pure oil sample or four fat signals of the fat-water phantom or vertebral bone marrow from Z spectra. Fat peak amplitudes were normalized to the total peak amplitude of water and all fat signals. Normalized fat peak amplitudes and FF were quantified and compared among vials of the fat-water phantom or between healthy volunteers and osteoporosis patients. An unpaired student's t-test and Pearson's correlation were conducted, with pless than 0.05 considered statistically significant. The results showed that the peanut oil spectra measured with the ZSI technique were in line with respective NMR spectra, with amplitudes of the six fat signal peaks significantly correlated between the two methods (y = x + 0.001, r = 0.996, p< 0.001 under a repetition time of 1.6 s; and y = 1.026x - 0.003, r = 0.996, p< 0.001 under a repetition time of 3.1 s). Moreover, ZSI-measured FF exhibited a significant correlation with prepared oil volumes (y = 0.876x + 1.290, r = 0.996, p< 0.001). The osteoporosis patients showed significantly higher normalized fat peak amplitudes and FF in the L4 vertebral body marrow than the healthy volunteers (all p< 0.01). In summary, the designed ZSI sequence is feasible for fatty acid characterization, and has the potential to facilitate the diagnosis and evaluation of diseases associated with fat alterations at 3 T.

Aliphatic and Olefinic Fat Suppression in the Orbit Using Polarity-altered Spectral and Spatial Selective Acquisition (PASTA) with Opposed Phase.

Fatty acid composition of the orbit makes it challenging to achieve complete fat suppression during orbit MR imaging. Implementation of a fat suppression technique capable of suppressing signals from saturated (aliphatic) and unsaturated (olefinic or protons at double-bonded carbon sites) fat would improve the visualization of an optical nerve. Furthermore, the ability to semi-quantify the fractions of aliphatic and olefinic fat may potentially provide valuable information in assessing orbit pathology. A phantom study was conducted on various oil samples on a clinical 3 Tesla scanner. The imaging protocol included three 2D fast spin echo (FSE) sequences: in-phase, polarity-altered spectral and spatial selective acquisition (PASTA), and a combination of PASTA with opposed phase in olefinic and aliphatic chemical shift. The results were validated against high-resolution 11.7T NMR and compared with images acquired with spectral attenuated inversion recovery (SPAIR) and chemical shift selective (CHESS) fat suppression techniques. In-vivo data were acquired on eight healthy subjects and were compared with the prior histological studies. PASTA with opposed phase achieved complete suppression of fat signals in the orbits and provided images of well-delineated optical nerves and muscles in all subjects. The olefinic fat fraction in the olive, walnut, and fish oil phantoms at 3T was found to be 5.0%, 11.2%, and 12.8%, respectively, whereas 11.7T NMR provides the following olefinic fat fractions: 6.0% for olive, 11.5% for walnut, and 12.6% for fish oils. For the in-vivo study, on average, olefinic fat accounted for 9.9% ± 3.8% of total fat while the aliphatic fat fraction was 90.1% ± 3.8%, in the normal orbits. We have introduced a new fat suppression technique using PASTA with opposed phase and applied it to human orbits. The purposed method achieves an excellent orbital fat suppression and the quantification of aliphatic and olefinic fat signals.

Improved visualization of median, ulnar nerves, and small branches in the wrist and palm using contrast-enhanced magnetic resonance neurography.

Magnetic resonance imaging of peripheral nerves in the wrist and palm is challenging due to the small size, tortuous course, complex surrounding tissues, and accompanying blood vessels. The occurrence of carpal palmar lesions leads to edema, swelling, and mass effect, which may further interfere with the display and identification of nerves. To evaluate whether contrast-enhanced magnetic resonance neurography (ceMRN) improves the visualization of the morphology and pathology of the median, ulnar nerves, and their small branches in the wrist and palm. An observational study. In total 57 subjects, including 36 volunteers and 21 patients with carpal palmar lesions, were enrolled and underwent ceMRN and non-contrast MRN (ncMRN) examination at 3.0 Tesla. The degree of vascular suppression, nerve visualization, diagnostic confidence, and lesion conspicuity was qualitatively assessed by two radiologists. Kappa statistics were obtained for inter-reader agreement. The signal-to-noise ratio, contrast ratio (CR), and contrast-to-noise ratio (CNR) of the median nerve were measured. The subjective ratings and quantitative measurements were compared between ncMRN and ceMRN. The inter-reader agreement was excellent (k > 0.8) for all qualitative assessments and visualization assessment of each nerve segment. Compared with ncMRN, ceMRN significantly improved vascular suppression in volunteers and patients (both p < 0.001). The ceMRN significantly enhanced nerve visualization of each segment (all p < 0.05) and diagnostic confidence in volunteers and patients (both p < 0.05). The ceMRN improved lesion conspicuity (p = 0.003) in patients. Quantitatively, ceMRN had significantly higher CRs of nerve versus subcutaneous fat, bone marrow, and vessels and CNR of nerve versus vessel than ncMRN (all p < 0.05). The ceMRN significantly improves the visualization of peripheral nerves and pathology in the wrist and palm by robustly suppressing the signals of fat, bone marrow, and especially vessels in volunteers and patients.

Value of the short time inversion recovery sequence of magnetic resonance imaging in the staging of Klippel-Trenaunay syndrome complicated with lymphedema

ObjectiveCurrently, the focus on limb lymphedema (LE) is on classification and staging. However, few scholars have conducted staging for Klippel-Trenaunay syndrome complicated LE (KTS-LE). This study aimed to investigate the value of the short time inversion recovery sequence of magnetic resonance imaging (MRI) in the staging of KTS-LE. MethodsForty-six patients who were diagnosed with KTS-LE were recruited for this retrospective study from July 2011 to November 2022. Referring to the clinical staging standard of lower extremity LE of the International Society of Lymphology in 2020, all patients were divided into three groups: stages I, II, and III. The MRI indicators of the three groups were recorded and statistically compared: LE range (unilateral bilateral, lower limbs, only thighs, only calves and ankles), abnormal parts (skin thickening, abnormal subcutaneous fat signal, abnormal muscle signal, muscle hypertrophy or contraction, abnormal bone signal, hyperostosis), and subcutaneous soft tissue signs (parallel line sign, grid sign, band sign, honeycomb sign, lymph lake sign, crescent sign, and nebula sign). ResultsThere was a significant difference in the honeycomb sign among the three periods (P = .028). There was a significant difference between stage II and stage I disease (P < .05). There was a significant difference between stage II and stage III disease (P < .05). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the honeycomb sign in diagnosing KTS-LE of stage II were 87.5%, 63.2%, 33.3%, 96.0%, and 67.4%, respectively. In contrast, the other signs were not statistically significant among the three periods. ConclusionsThe short time inversion recovery sequence of MRI is of great value in KTS-LE. The honeycomb sign is an important imaging indicator for the diagnosis of stage II disease. It is necessary to evaluate the severity of edema with MRI for KTS-LE, which is very important for therapeutic options.

Comparative 4D Label-Free Quantitative Proteomic Analysis of Bombus terrestris Provides Insights into Proteins and Processes Associated with Diapause.

Diapause, an adaptative strategy for survival under harsh conditions, is a dynamic multi-stage process. Bombus terrestris, an important agricultural pollinator, is declining in the wild, but artificial breeding is possible by imitating natural conditions. Mated queen bees enter reproductive diapause in winter and recover in spring, but the regulatory mechanisms remain unclear. Herein, we conducted a comparative 4D label-free proteomic analysis of queen bees during artificial breeding at seven timepoints, including pre-diapause, diapause, and post-diapause stages. Through bioinformatics analysis of proteomic and detection of substance content changes, our results found that, during pre-diapause stages, queen bees had active mitochondria with high levels of oxidative phosphorylation, high body weight, and glycogen and TAG content, all of which support energy consumption during subsequent diapause. During diapause stages, body weight and water content were decreased but glycerol increased, contributing to cold resistance. Dopamine content, immune defense, and protein phosphorylation were elevated, while fat metabolism, protein export, cell communication, signal transduction, and hydrolase activity decreased. Following diapause termination, JH titer, water, fatty acid, and pyruvate levels increased, catabolism, synaptic transmission, and insulin signaling were stimulated, ribosome and cell cycle proteins were upregulated, and cell proliferation was accelerated. Meanwhile, TAG and glycogen content decreased, and ovaries gradually developed. These findings illuminate changes occurring in queen bees at different diapause stages during commercial production.

Fetal MRI-Based Body and Adiposity Quantification for Small for Gestational Age Perinatal Risk Stratification.

Small for gestational age (SGA) fetuses are at risk for perinatal adverse outcomes. Fetal body composition reflects the fetal nutrition status and hold promise as potential prognostic indicator. MRI quantification of fetal anthropometrics may enhance SGA risk stratification. Smaller, leaner fetuses are malnourished and will experience unfavorable outcomes. Prospective. 40 SGA fetuses, 26 (61.9%) females: 10/40 (25%) had obstetric interventions due to non-reassuring fetal status (NRFS), and 17/40 (42.5%) experienced adverse neonatal events (CANO). Participants underwent MRI between gestational ages 30 + 2 and 37 + 2. 3-T, True Fast Imaging with Steady State Free Precession (TruFISP) and T1-weighted two-point Dixon (T1W Dixon) sequences. Total body volume (TBV), fat signal fraction (FSF), and the fat-to-body volumes ratio (FBVR) were extracted from TruFISP and T1W Dixon images, and computed from automatic fetal body and subcutaneous fat segmentations by deep learning. Subjects were followed until hospital discharge, and obstetric interventions and neonatal adverse events were recorded. Univariate and multivariate logistic regressions for the association between TBV, FBVR, and FSF and interventions for NRFS and CANO. Fisher's exact test was used to measure the association between sonographic FGR criteria and perinatal outcomes. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated. A P-value <0.05 was considered statistically significant. FBVR (odds ratio [OR] 0.39, 95% confidence interval [CI] 0.2-0.76) and FSF (OR 0.95, CI 0.91-0.99) were linked with NRFS interventions. Furthermore, TBV (OR 0.69, CI 0.56-0.86) and FSF (OR 0.96, CI 0.93-0.99) were linked to CANO. The FBVR sensitivity/specificity for obstetric interventions was 85.7%/87.5%, and the TBV sensitivity/specificity for CANO was 82.35%/86.4%. The sonographic criteria sensitivity/specificity for obstetric interventions was 100%/33.3% and insignificant for CANO (P = 0.145). Reduced TBV and FBVR may be associated with higher rates of obstetric interventions for NRFS and CANO. 2 TECHNICAL EFFICACY: Stage 5.

Analisis Pemeriksaan MRI Pelvis Pada Kasus Kanker Serviks Di Instalasi Radiologi RSUP Persahabatan

The aim of this research is to find out the procedures for Pelvic MRI examinations in Cervical Cancer Cases at the Radiology Installation at Persahabatan Hospital, to find out the reasons for using T1W SPIR and to find out the reasons for using T2W SPAIR in Pelvic MRI examinations in cervical cancer cases. This type of research uses descriptive qualitative methods with a case study approach. Data collection methods are carried out through observation, interviews and documentation. Then data analysis was carried out using open coding charts and categorization tables, so that conclusions could be drawn. The results of this study indicate that the Pelvic MRI examination procedure in cases of cervical cancer at Persahabatan Hospital using contrast media requires special preparation, namely the patient fasting from eating fibrous foods 1 day before the examination, taking laxatives 12 hours before the examination, and checking urea creatinine. The patient is injected with 20 cc of ultrasonic gel in the rectum and vagina which functions as a marker. The purpose of using the T1W SPIR sequence is to compare enhancement before and after administration of contrast media. The use of T2W SPAIR in pelvic MRI examinations to assess pathological fluid by suppressing fat signals.

Validity of an automated screening Dixon technique for quantifying hepatic steatosis in living liver donors.

This retrospective study aimed to evaluate the validity of an automated screening Dixon (e-DIXON) technique for quantifying hepatic steatosis in living liver-donor patients by comparison with magnetic resonance spectroscopy (MRS) as a reference standard. A total of 285 living liver-donor candidates were examined with the e-DIXON technique and single-voxel MRS to assess hepatic steatosis and iron deposition between January 2014 and February 2019. The sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of the e-DIXON technique for hepatic steatosis were calculated. The mean fat signal fractions obtained in MRS were compared between the donors diagnosed with hepatic steatosis and the normal group. The mean R2 values of donors with or without hepatic siderosis also were compared. The e-DIXON technique diagnosed normal in 133 (47%), fat in 124 (44%), iron in one (0.4%), and a combination of both fat and iron in 27 (10%) donors. The sensitivity, specificity, PPV, and NPV ​​for diagnosing hepatic steatosis were 94%, 70%, 64%, and 96%, respectively. There was a significant difference in the mean fat signal fraction obtained in MRS between the steatosis and normal groups (p < 0.001), but R2 values were not significantly different between siderosis and normal groups (p = 0.11). The e-DIXON technique showed a strong correlation with MRS in fat measurement (r2 = 0.92, p < 0.001). The e-DIXON technique reliably screens for hepatic steatosis but may not accurate for detecting hepatic iron deposition.

Multi-echo-based fat artifact correction for CEST MRI at 7 T.

CEST MRI is influenced by fat signal, which can reduce the apparent CEST contrast or lead to pseudo-CEST effects. Our goal was to develop a fat artifact correction based on multi-echo fat-water separation that functions stably for 7 T knee MRI data. Our proposed algorithm utilizes the full complex data and a phase demodulation with an off-resonance map estimation based on the Z-spectra prior to fat-water separation to achieve stable fat artifact correction. Our method was validated and compared to multi-echo-based methods originally proposed for 3 T by Bloch-McConnell simulations and phantom measurements. Moreover, the method was applied to in vivo 7 T knee MRI examinations and compared to Gaussian fat saturation and a published single-echo Z-spectrum-based fat artifact correction method. Phase demodulation prior to fat-water separation reduced the occurrence of fat-water swaps. Utilizing the complex signal data led to more stable correction results than working with magnitude data, as was proposed for 3 T. Our approach reduced pseudo-nuclear Overhauser effects compared to the other correction methods. Thus, the mean asymmetry contrast at 3.5 ppm in cartilage over five volunteers increased from -9.2% (uncorrected) and -10.6% (Z-spectrum-based) to -1.5%. Results showed higher spatial stability than with the fat saturation pulse. Our work demonstrates the feasibility of multi-echo-based fat-water separation with an adaptive fat model for fat artifact correction for CEST MRI at 7 T. Our approach provided better fat artifact correction throughout the entire spectrum and image than the fat saturation pulse or Z-spectrum-based correction method for both phantom and knee imaging results.

Structured low-rank reconstruction for navigator-free water/fat separated multi-shot diffusion-weighted EPI.

Multi-shot diffusion-weighted EPI allows an increase in image resolution and reduced geometric distortions and can be combined with chemical-shift encoding (Dixon) to separate water/fat signals. However, such approaches suffer from physiological motion-induced shot-to-shot phase variations. In this work, a structured low-rank-based navigator-free algorithm is proposed to address the challenge of simultaneously separating water/fat signals and correcting for physiological motion-induced shot-to-shot phase variations in multi-shot EPI-based diffusion-weighted MRI. We propose an iterative, model-based reconstruction pipeline that applies structured low-rank regularization to estimate and eliminate the shot-to-shot phase variations in a data-driven way, while separating water/fat images. The algorithm is tested in different anatomies, including head-neck, knee, brain, and prostate. The performance is validated in simulations and in-vivo experiments in comparison to existing approaches. In-vivo experiments and simulations demonstrated the effectiveness of the proposed algorithm compared to extra-navigated and an alternative self-navigation approach. The proposed algorithm demonstrates the capability to reconstruct in the multi-shot/Dixon hybrid space domain under-sampled datasets, using the same number of acquired EPI shots compared to conventional fat-suppression techniques but eliminating fat signals through chemical-shift encoding. In addition, partial Fourier reconstruction can also be achieved by using the concept of virtual conjugate coils in conjunction with the proposed algorithm. The proposed algorithm effectively eliminates the shot-to-shot phase variations and separates water/fat images, making it a promising solution for future DWI on different anatomies.

The diagnostic value of morphological features of fat deposition of sacroiliac joint steatosis in axial spondyloarthritis.

Findings of fatty lesions in the context of other imaging manifestations, especially bone marrow edema and erosions can effectively assist in the diagnosis of axSpA. Chemical shift-encoded MRI is a sequence which allows for the quantification of fat signal and has been applied in the imaging evaluation of the SIJ in axSpA. The objective of this study was to investigate the diagnostic performance of morphological features of fatty lesions visualized by CSE-MRI in the imaging evaluation of SIJ in axSpA. Fatty lesions with morphological features (subchondral, homogeneity and distinct border) were assessed and recorded as a binary variable in each quadrant of the SIJ. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for different morphological features as well as the anatomical distribution in patients with nr-axSpA and r-axSpA. T1-weighted images and CSE-MRI fat fraction maps were directly compared in the recognition of different morphological features. Eighty-two patients [non-SpA (n = 21), nr-axSpA (n = 23), r-axSpA (n = 38)] with lower back pain (LBP) were enrolled. Presence of the three morphological features of fatty lesions had a specificity of 90.48% in axSpA. The sensitivities of being subchondral, homogeneity and distinct border were 52.17, 39.13 and 39.13% in nr-axSpA on T1-weighted images. For patients with r-axSpA, the sensitivities reached 86.84, 76.32 and 57.89%. No significant difference was found in the distribution of fatty lesions between T1-weighted images and CSE-MRI. However, CSE-MRI fat fraction maps could detect significantly more fatty lesions with homogeneity (p = 0.0412) and distinct border (p = 0.0159) than T1-weighted images in the sacroiliac joint, but not subchondral lesions (p = 0.6831). The homogeneity and distinct border are more relevant for the diagnosis of axSpA. Moreover, CSE-MRI could detect more typical morphological features of fatty lesions than T1-weighted images in showing these two features. The presence of all three features was more likely to be indicative of axSpA.

Non-Alcoholic Fatty Liver Disease-Associated Hepatocellular Carcinoma: Effect of Hepatic Steatosis on Major Hepatocellular Carcinoma Features at MRI

Background Non-alcoholic fatty liver disease has become the leading chronic liver disease in the developed world, with a prevalence of 6%-35%. Its pathological spectrum ranges from simple steatosis (non-alcoholic fatty liver) to different degrees of inflammation and liver cell damage [nonalcoholic steatohepatitis (NAFLD)]. NAFLD has gained attention in recent years because of its association with hepatocellular carcinoma (HCC). Objective To see how hepatic fat fraction affects LIRADS major hepatocellular carcinoma features on magnetic resonance imaging. Patients and Methods Our study included 60 patients who had had a liver MR scan and exhibited MRI features in keeping with HCC. We categorize the patients into two groups: hepatic steatosis and non- hepatic steatosis groups based on MRI hepatic fat signal fraction. LI-RADS major and ancillary features were evaluated in all HCCs. Between October 2021 and April 2022, a retrospective search was conducted to find all patients with HCC who underwent an MRI of the liver at the radiology department of Ain Shams University's Faculty of medicine. Results In the current study, a higher proportion of HCCs show non- enhancing capsule in patients with hepatic steatosis; 5 HCC (5/30; 16.7%), while in the non-hepatic steatosis group no HCCs 0 (0%) showed non-enhancing capsule. The effect of ancillary features on diagnostic accuracy is still being researched. As regards the impact of the degree of fatty liver on the major and ancillary HCC features, the “enhancing capsule”, “mild-moderate T2 hyperintensity” and “restricted DWI” features are less commonly seen in cases of moderate to severe hepatic steatosis than in those of mild hepatic steatosis. Our study also showed that HCCs tends to be of a smaller size as the hepatic steatosis degree increased. Conclusion The findings of our retreopective study are coincide with a recent retrospective studies demonstrated that “enhancing capsule” feature of HCC was less frequently observed in patients with hepatic steatosis compared to non-hepatic steatosis patients. We compared the MRI features of HCC in patients with hepatic steatosis to those in patients without hepatic steatosis. Our findings imply that existing imaging criteria for the noninvasive characterization of HCC in individuals with hepatic steatosis should be utilised with care.

Computed diffusion-weighted imaging with a low-apparent diffusion coefficient-pixel cut-off technique for breast cancer detection.

This study aimed to compare the image quality and diagnostic performance of computed diffusion-weighted imaging (DWI) with low-apparent diffusion coefficient (ADC)-pixel cut-off technique (cDWI cut-off) and actual measured DWI (mDWI). Eighty-seven consecutive patients with malignant breast lesions and 72 with negative breast lesions who underwent breast MRI were retrospectively evaluated. Computed DWI with high b-values of 800, 1200, and 1500 s/mm2 and ADC cut-off thresholds of none, 0, 0.3, and 0.6 (×10-3 mm2/s) were generated from DWI with two b-values (0 and 800 s/mm2). To identify the optimal conditions, two radiologists evaluated the fat suppression and lesion reduction failure using a cut-off technique. The contrast between breast cancer and glandular tissue was evaluated using region of interest analysis. Three other board-certified radiologists independently assessed the optimised cDWI cut-off and mDWI data sets. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis. When an ADC cut-off threshold of 0.3 or 0.6 (× 10-3 mm2/s) was applied, fat suppression improved significantly (p < .05). The contrast of the cDWI cut-off with a b-value of 1200 or 1500 s/mm2 was better than the mDWI (p < .01). The ROC area under the curve for breast cancer detection was 0.837 for the mDWI and 0.909 for the cDWI cut-off (p < .01). The cDWI cut-off provided better diagnostic performance than mDWI for breast cancer detection. Using the low-ADC-pixel cut-off technique, computed DWI can improve diagnostic performance by increasing contrast and eliminating un-suppressed fat signals.

Characteristics of paraspinal muscle fat infiltration in asymptomatic Chinese adults: a cross-sectional study.

Paraspinal muscle fat infiltration is closely related to the occurrence and development of lumbar spine disorders and postoperative complications. This study aimed to explore the effects of age, sex, muscle, and level on paraspinal muscle fat infiltration among Chinese adults to identify the best single level of assessing whole-level paraspinal muscle fat infiltration and to define the standardized identification thresholds for paraspinal muscle fat infiltration by means of magnetic resonance imaging. This was a single-center, cross-sectional study conducted on 336 asymptomatic Chinese volunteers aged 20 to 69 years recruited from Beijing and surrounding communities through designed advertisements from May 2022 to October 2022. The fat signal fraction of multifidus (FSFMF), erector spinae (FSFES), psoas major (FSFPM), and the sum of multifidus, erector spinae, and psoas major (FSFTotal) at lumbar levels L1-L5 were measured with magnetic resonance imaging. The Student t-test and Mann-Whitney test were performed, and Pearson correlations and intraclass correlation coefficients were determined. Subgroups were compared using analysis of variance followed by a post hoc Bonferroni test or Kruskal-Wallis test. FSFTotal (14.02%±4.71% vs. 10.34±4.08%; P<0.001), FSFMF (21.14%±6.77% vs. 16.21%±6.26%; P<0.001), and FSFES (15.97%±5.56% vs. 12.37%±4.80%; P<0.001) were higher in females than in males and increased with age and lumbar level, whereas FSFPM did not significantly differ by age (all P values >0.05) or sex (P=0.12) and showed a decreasing trend from L1 to L5. The FSFTotal at L4 showed both the strongest correlation (Pearson correlation coefficient =0.95; P<0.001) and agreement (intraclass correlation coefficient =0.92; P<0.001) with the whole-level FSFTotal. Pathological paraspinal muscle fat infiltration identification thresholds of FSFTotal, FSFMF, FSFES, and FSFPM were 10.0-33.9%, 19.2-47.4%, 16.2-43.6%, and 4.8%, respectively, in each age (range, 20-69 years) and sex group. In asymptomatic Chinese adults, paraspinal muscle fat infiltration can be influenced by age, sex, muscle type, and location. The L4 level can serve as an optimal substitution in whole-level fat infiltration measurement. We present the first data concerning the identification thresholds of pathological paraspinal muscle fat infiltration, which will provide a valuable resource for researchers in the field.

Reduced adipose tissue in growth-restricted fetuses using quantitative analysis of magnetic resonance images.

Fat-water MRI can be used to quantify tissues' lipid content. We aimed to quantify fetal third trimester normal whole-body subcutaneous lipid deposition and explore differences between appropriate for gestational age (AGA), fetal growth restriction (FGR), and small for gestational age fetuses (SGAs). We prospectively recruited women with FGR and SGA-complicated pregnancies and retrospectively recruited the AGA cohort (sonographic estimated fetal weight [EFW] ≥ 10th centile). FGR was defined using the accepted Delphi criteria, and fetuses with an EFW < 10th centile that did not meet the Delphi criteria were defined as SGA. Fat-water and anatomical images were acquired in 3T MRI scanners. The entire fetal subcutaneous fat was semi-automatically segmented. Three adiposity parameters were calculated: fat signal fraction (FSF) and two novel parameters, i.e., fat-to-body volume ratio (FBVR) and estimated total lipid content (ETLC = FSF*FBVR). Normal lipid deposition with gestation and differences between groups were assessed. Thirty-seven AGA, 18 FGR, and 9 SGA pregnancies were included. All three adiposity parameters increased between 30 and 39weeks (p < 0.001). All three adiposity parameters were significantly lower in FGR compared with AGA (p ≤ 0.001). Only ETLC and FSF were significantly lower in SGA compared with AGA using regression analysis (p = 0.018-0.036, respectively). Compared with SGA, FGR had a significantly lower FBVR (p = 0.011) with no significant differences in FSF and ETLC (p ≥ 0.053). Whole-body subcutaneous lipid accretion increased throughout the third trimester. Reduced lipid deposition is predominant in FGR and may be used to differentiate FGR from SGA, assess FGR severity, and study other malnourishment pathologies. Fetuses with growth restriction have reduced lipid deposition than appropriately developing fetuses measured using MRI. Reduced fat accretion is linked with worse outcomes and may be used for growth restriction risk stratification. • Fat-water MRI can be used to assess the fetal nutritional status quantitatively. • Lipid deposition increased throughout the third trimester in AGA fetuses. • FGR and SGA have reduced lipid deposition compared with AGA fetuses, more predominant in FGR.

MRI Case Report of Perianal Fistula with T2 TSE SPIR Sequence

MRI is a diagnostic imaging tool crucial for pelvic examination in perianal fistula cases. MRI imaging offers some advantages, especially in showing the area of spesi and secondary dilatation. Both have a high recurrence rate after surgery and an important role in determining surgical outcomes and minimizing complications. This study aims to evaluate pelvic MRI examination of perianal fistulas using the T2 TSE SPIR (Turbo Spin Echo Spectral Presaturation with Inversion Recovery) sequence. Research design used a qualitative descriptive method with participatory observation through a case study approach to Perianal Fistula using T2 TSE_SPIR. It was carried out at the Radiology Department of Mayapada Hospital in South Jakarta from August to December 2022. The MRI equipment Philips Achieva 1.5 Tesla with Sense Body Coil. MRI contrast agent of gadoteric acid, Vitamin E capsule, was attached to the perianal fistula location to make it easier for the radiologist to see the path of the perianal fistula. The results of Pelvis MRI images in perianal fistulas using the T2 TSE SPIR sequence shown with clear boundaries of perianal fistulas with anal organs, sigmoid colon, bladder, and prostate between one organ and another. Implementing the selection of the T2 TSE SPIR sequence to visualize fluid images becomes hyper-intensive by suppressing fat signals so that only fluid is visible in the perianal abscess and fistula images.

Comparison of Short-Tau Inversion Recovery With Short-Tau Inversion Recovery-Slice Encoding for Metal Artifact Correction for Spine Imaging at 1.5 T in the Setting of Metallic Implants.

To compare the image quality of short-tau inversion recovery (STIR) and the STIR-slice encoding for metal artifact correction (SEMAC) sequence for postsurgery spine magnetic resonance imaging (MRI). Twenty-nine patients with metallic spinal implants who underwent spinal 1.5 T MRI with STIR and STIR-SEMAC sequences between July 2016 and November 2020 were retrospectively enrolled. Qualitative assessments were performed using 5-point scales; higher scores indicated better image quality. For screw metal artifact analysis, scores were obtained for artifacts on vertebral bodies and neural foramina, screw artifact widths, and bone marrow signal intensities. For patient-based analysis, scores were obtained for imaging quality and fat suppression quality, signal intensity, and cerebrospinal fluid noise. A paired t test was performed for statistical analyses. We analyzed 163 screws in 29 patients. In the screw metal artifact analysis, the vertebral body and neural foramen scores were significantly higher for the STIR-SEMAC images than for the STIR (all P < 0.001). The artifact width in the STIR-SEMAC images (9.8 ± 3.4 mm) was significantly smaller than that in the STIR images (16.0 ± 4.7 mm, P < 0.001). In patient-based analysis, the fat suppression and imaging quality scores were significantly higher for the STIR-SEMAC images than for the STIR images (all P < 0.001). The cerebrospinal fluid signal intensity, noise, and signal-to-noise ratios were significantly higher for the STIR images (all P < 0.005). Short-tau inversion recovery-SEMAC sequences provide good metallic artifact reduction and fat suppression for postsurgery spine 1.5 T MRI.

Hepatic Steatosis After Partial Pancreatectomy in a Cohort of Patients with Intraductal Papillary Mucinous Neoplasm

Nonalcoholic fatty liver disease (NAFLD) has been observed in patients after partial pancreatectomy. Previous studies have been performed on oncologic patients who underwent partial pancreatectomy and received adjuvant chemotherapy. By studying a cohort of patients with intraductal papillary mucinous neoplasms (IPMNs) who did not receive chemotherapy, the authors investigate the isolated effect of partial pancreatectomy on the development of fatty liver. A retrospective search for patients with pancreatic IPMNs who underwent partial pancreatectomy at an academic center from 2006 to 2014 identified 63 patients, including 42 who had pancreaticoduodenectomy (PD) and 21 who had distal pancreatectomy (DP). Fourteen patients with preoperative hepatic steatosis, diabetes, obesity, on steroid therapy, history of malignancy, or incomplete data were excluded. No patient received chemotherapy. Liver fat signal fraction (LFSF) was computed by the Dixon method using pre- and postoperative in- and out-of-phase MRI. Of the 49 patients included in the study, 29 (59%) underwent PD and 20 (41%) underwent DP. A total of 17 patients (34%) developed fatty liver after surgery. The entire cohort developed significant weight loss, 72.1 versus69.4kg (P<0.01). Postoperatively, there was significant increase in LFSF, 1.3% versus 9.6% following PD (P<0.01), and 2.1% versus 9.4% following DP (P=0.01). Partial pancreatectomy increases the risk of NAFLD independent of chemotherapy-induced hepatotoxicity. The underlying mechanism remains unclear and possibly related to pancreatic exocrine insufficiency and malnutrition.