Use of magnetic resonance elastography for assessing liver functional reserve:A clinical study

AIM: To investigate the value of magnetic resonance elastography(MRE) with regard to assessing liver functional reserve.METHODS: Data from inpatients diagnosed with a liver tumor at an interventional radiology department from July 2013 to June 2014 were analyzed. A 3.0 Tesla magnetic resonance unit was used to scan 32 patients with confirmed diagnoses of hepatocellular carcinoma(HCC); an MRE sequence was added to the protocol, and the data were reconstructed and analyzed by two attending radiologists. Regions of interest were identified in different slices of the non-tumor liver parenchyma to measure average stiffness. In addition, the indocyanine green(ICG) test was performed no more than 1 wk before or after the magnetic resonance examination for all 32 patients; the ICG retention rate at 15 min(ICGR-15) and the ICG plasma clearance rate(ICG-K) were recorded. Correlational analyses were performed between the liver stiffness values and the ICGR-15 as well as between the liver stiffness values and the ICG-K.RESULTS: Magnetic resonance imaging, including an MRE sequence and the ICG test, was performed successfully in all 32 enrolled patients. None of the patients developed complications. The mean ± SD of the elasticity values measured by the two attending radiologists were 4.7 ± 2.2 k Pa and 4.7 ± 2.1 k Pa, respectively. The average liver stiffness value of the non-tumor parenchyma measured using MRE in HCC patients was 4.7 ± 2.2 k Pa. The average ICGR-15 was 0.089 ± 0.077, and the average ICG-K was 0.19 ± 0.07. We found that the liver stiffness value of the non-tumor parenchyma was significantly and positively related to the ICGR-15(r = 0.746, P < 0.01) as well as significantly and negatively related to the ICG-K(r =-0.599, P < 0.01). The ICGR-15 was significantly and negatively related to the ICG-K(r =-0.852, P < 0.01).CONCLUSION: MRE is accurate and non-invasive; furthermore, it can be used to effectively assess the liver functional reserve of HCC patients.

Three-Tesla magnetic resonance elastography for hepatic fibrosis:Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

AIM:To evaluate the feasibility of 3-Tesla magnetic resonance elastography(MRE)for hepatic fibrosis and to compare that with diffusion-weighted imaging(DWI)and gadoxetic acid-enhanced magnetic resonance(MR)imaging.METHODS:Forty-two patients were included in the study.On MRE,mean stiffness values were measured on the elastograms in kilopascals.The apparent diffusion coefficient(ADC)of the liver was measured using DWI.On gadoxetic acid enhanced MR,the contrast enhancement index(CEI)was calculated as signal intensity(SI)post/SIpre,where SIpost is liver-to-muscle SI ratio on hepatobiliary phase images and SIpre is that on nonenhanced images.Correlation between aspartate aminotransferase to the platelet ratio index(APRI)and three MR parameters was assessed.Each MR parameter was compared between a hepatic fibrosis(HF)group and non-hepatic fibrosis(n HF)group.RESULTS:Liver stiffness showed strong positive correlation with APRI[Spearman correlation coeffiecient(r)=0.773,P<0.0001],while ADC and CEI showed weak or prominent negative correlation(r=-0.28 and-0.321,respectively).In the HF group,only liver stiffness showed strong correlation with APRI(r=0.731,P<0.0001).Liver stiffness,ADC,and APRI were significantly different between the HF group and n HF group.CONCLUSION:MRE at 3-Tesla could be a feasible method for the assessment of hepatic fibrosis.

Predicting gastroesophageal varices through spleen magnetic resonance elastography in pediatric liver fibrosis

BACKGROUND A recent retrospective study confirmed that hepatic stiffness and splenic stiffness measured with magnetic resonance elastography(MRE) are strongly associated with the presence of esophageal varices. In addition, strong correlations have been reported between splenic stiffness values measured with MRE and hepatic venous pressure gradients in animal models. However, most studies have been conducted on adult populations, and previous pediatric MRE studies have only demonstrated the feasibility of MRE in pediatric populations, while the actual clinical application of spleen MRE has been limited.AIM To assess the utility of splenic stiffness measurements by MRE to predict gastroesophageal varices in children.METHODS We retrospectively reviewed abdominal MRE images taken on a 3 T system in pediatric patients. Patients who had undergone Kasai operations for biliary atresia were selected for the Kasai group, and patients with normal livers and spleens were selected for the control group. Two-dimensional spin-echo echoplanar MRE acquisition centered on the liver, with a pneumatic driver at 60 Hz and a low amplitude, was performed to obtain hepatic and splenic stiffness values. Laboratory results for aspartate aminotransferase to platelet ratio index(APRI) were evaluated within six months of MRE, and the normalized spleen size ratio was determined with the upper normal size limit. All Kasai group patients underwent gastroesophageal endoscopy during routine follow-up. The MannWhitney U test, Kendall's tau b correlation and diagnostic performance analysis using the area under the curve(AUC) were performed for statistical analysis.RESULTS The median spleen MRE value was 5.5 kPa in the control group(n = 9, age 9-18 years, range 4.7-6.4 kPa) and 8.6 kPa in the Kasai group(n = 22, age 4-18 years,range 5.0-17.8 kPa). In the Kasai group, the APRI, spleen size ratio and spleen MRE values were higher in patients with portal hypertension(n = 11) than in patients without(n = 11)(all P < 0.001) and in patients with gastroesophageal varices(n = 6) than in patients without(n = 16)(all P < 0.05), even though their liver MRE values were not different. The APRI(τ = 0.477, P = 0.007), spleen size ratio(τ = 0.401, P = 0.024) and spleen MRE values(τ = 0.426, P = 0.016) also correlated with varices grades. The AUC in predicting gastroesophageal varices was 0.844 at a cut-off of 0.65(100% sensitivity and 75% specificity) for the APRI,and 0.844 at a cut-off of 9.9 kPa(83.3% sensitivity and 81.3% specificity) for spleen MRE values.CONCLUSION At a cut-off of 9.9 kPa, spleen MRE values predicted gastroesophageal varices as well as the APRI and spleen size ratio in biliary atresia patients after the Kasai operation. However, liver MRE values were not useful for this purpose.

General review of magnetic resonance elastography

Magnetic resonance elastography(MRE) is an innovative imaging technique for the non-invasive quantification of the biomechanical properties of soft tissues via the direct visualization of propagating shear waves in vivo using a modified phase-contrast magnetic resonance imaging(MRI) sequence. Fundamentally,MRE employs the same physical property that physicians utilize when performing manual palpation- that healthy and diseased tissues can be differentiated on the basis of widely differing mechanical stiffness. By performing "virtual palpation ",MRE is able to provide information that is beyond the capabilities of conventional morphologic imaging modalities. In an era of increasing adoption of multi-parametric imaging approaches for solving complex problems,MRE can be seamlessly incorporated into a standard MRI examination to provide a rapid,reliable and comprehensive imaging evaluation at a single patient appointment. Originally described by the Mayo Clinic in 1995,the technique represents the most accurate non-invasive method for the detection and staging of liver fibrosis and is currently performed in more than 100 centers worldwide. In this general review,the mechanical properties of soft tissues,principles of MRE,clinical applications of MRE in the liver and beyond,and limitations and future directions of this discipline-are discussed. Selected diagrams and images are provided for illustration.

Magnetic resonance elastography is accurate in detecting advanced fibrosis in autoimmune hepatitis

To assess the value of magnetic resonance elastography(MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis(AIH).METHODS In this retrospective study, 36 patients(19 treated and 17 untreated) with histologically confirmed AIH and liver biopsy performed within 3 mo of MRE were identified at a tertiary care referral center. Liver stiffness(LS) with MRE was calculated by a radiologist, and inflammation grade and fibrosis stage in liver biopsy was assessed by a pathologist in a blinded fashion. Two radiologistsevaluated morphological features of cirrhosis on conventional magnetic resonance imaging(MRI). Accuracy of MRE was compared to laboratory markers and MRI for detection of advanced fibrosis/cirrhosis.RESULTS Liver fibrosis stages of 0, 1, 2, 3 and 4 were present in 4, 6, 7, 6 and 13 patients respectively. There were no significant differences in distribution of fibrosis stage and inflammation grade between treated and untreated patient groups. LS with MRE demonstrated stronger correlation with liver fibrosis stage in comparison to laboratory markers for chronic liver disease(r = 0.88 vs-0.48-0.70). A trend of decreased mean LS in treated patients compared to untreated patients was observed(3.7 k Pa vs 3.84 k Pa) but was not statistically significant. MRE had an accuracy/sensitivity/specificity/positive predictive value/negative predictive value of 0.97/90%/100%/100%/90% and 0.98/92.3%/96%/92.3%/96% for detection of advanced fibrosis and cirrhosis, respectively. The performance of MRE was significantly better than laboratory tests for detection of advanced fibrosis(0.97 vs 0.53-0.80, P < 0.01), and cirrhosis(0.98 vs 0.58-0.80, P < 0.01) and better than conventional MRI for diagnosis of cirrhosis(0.98 vs 0.78, P = 0.002).CONCLUSION MRE is a promising modality for detection of advanced fibrosis and cirrhosis in patients with AIH with superior diagnostic accuracy compared to laboratory assessment and MRI.

Skeletal muscle stiffness as measured by magnetic resonance elastography after chronic spinal cord injury:a cross-sectional pilot study

Skeletal muscle stiffness is altered after spinal cord injury(SCI).Assessing muscle stiffness is essential for rehabilitation and pharmaceutical interventions design after SCI.The study used magnetic resonance elastography to assess the changes in stiffness after chronic SCI compared to matched able-bodied controls and determine its association with muscle size,spasticity,and peak torque in persons with SCI.Previous studies examined the association between muscle stiffness and spasticity,however,we are unaware of other studies that examined the effects of muscle composition on stiffness after SCI.Ten participants(one female)with chronic SCI and eight(one female)matched able-bodied controls participated in this cross-sectional study.Magnetic resonance elastography was utilized to monitor stiffness derived from shear waves propagation.Modified Ashworth scale was used to evaluate spasticity scores in a blinded fashion.Peak isometric and isokinetic torques were measured using a biodex dynamometer.Stiffness values were non-significantly lower(12.5%;P=0.3)in the SCI group compared to able-bodied controls.Moreover,stiffness was positively related to vastus lateralis whole muscle cross-sectional area(CSA)(r2=0.64,P<0.005)and vastus lateralis absolute muscle CSA after accounting for intramuscular fat(r2=0.78,P<0.0007).Stiffness was also positively correlated to both isometric(r2=0.55-0.57,P<0.05)and isokinetic peak(r2=0.46-0.48,P<0.05)torques.Our results suggest that larger clinical trial is warranted to confirm the preliminary findings that muscle stiffness is altered after SCI compared to healthy controls.Stiffness appeared to be influenced by infiltration of intramuscular fat and modestly by the spasticity of the paralyzed muscles.The preliminary data indicated that the relationship between muscle stiffness and peak torque is not altered with changing the frequency of pulses or angular velocities.All study procedures were approved by the Institutional Review Board at the Hunter Holmes McGuire VA Medical Center,USA(IRB#:02314)on May 3,2017.

Magnetic Resonance Elastography for Liver Fibrosis in Methotrexate Treatment

Introduction: Hepatic magnetic resonance elastography (MRE) allows for noninvasive assessment of liver fibrosis. The purpose of this study was to evaluate the usefulness of MRE in detecting and quantifying liver fibrosis in patients with rheumatoid arthritis (RA) who have received methotrexate (MTX). Methods: The association between mean liver stiffness value as determined by MRE and variables of interest was determined. The decision for a liver biopsy in participants with an abnormal liver stiffness was made based on clinical judgment. Results: Sixty-five RA patients were enrolled. Mean liver stiffness value by MRE was abnormal in 7 patients, suggestive of hepatic injury. As a result of findings from the MRE, biopsies were performed in 5 patients and all correlated with elevated liver stiffness values. Elevated mean liver stiffness values were associated with body mass index (BMI) (OR = 1.18 per 1 kg/m2;95% CI: 1.03, 1.36;p = 0.017). Neither the total MTX dose nor the duration of MTX treatment was associated with mean liver stiffness value (p = 0.51 and P = 0.20, respectively). Conclusion: MRE provides a reliable, non-invasive assessment of liver fibrosis in patients with RA receiving MTX. Patients with RA receiving MTX who have an elevated BMI may be at increased risk for chronic hepatic injury, regardless of MTX cumulative dose or duration of treatment.

Directional Filter, Local Frequency Estimate and Algebraic Inversion of Differential Equation of Psoas Major Magnetic Resonance Elastography

Magnetic resonance elastography (MRE) can visualize the shear wave propagation of in vivo tissues, which can be mapped into viscoelastic properties. No study has measured the biomechanical properties of the PM muscle in vivo using MRE. In this study, we evaluated stiffness values calculated by local frequency estimate (LFE) and algebraic inversion of differential equation (AIDE) in PM-MRE. The PM muscles of 17 healthy male volunteers were scanned in supine position by MRE. The Laplacian-based estimate (LBE) phase wrapped image data were filtered by gaussian-bandpass filter (GBF), and by both directional and GBF. LFE (MREWave) and AIDE wave inversion methods were used to calculate the respective elastograms. The wave interferences were removed by directional filtering, and smooth wave fields were obtained. The stiffness values calculated by LFE of non-DF images were 1.39 ± 0.25 kPa and 1.33 ± 0.22 kPa for right and left PM respectively, whereas for DF images, they were 1.26 ± 0.20 kPa for right PM and 1.18 ± 0.28 kPa for left PM. The stiffness values calculated by AIDE of non-DF images were 0.78 ± 0.10 kPa and 0.78 ± 0.13 kPa for right and left PM respectively, whereas for DF images, they were 0.73 ± 0.12 kPa for right PM and 0.74 ± 0.11 kPa for left PM. There was no statistically significant difference in mean values of stiffness with/without applying directional filter whereas there was a statistically significant difference in mean values of stiffness between LFE and AIDE. Both LFE and AIDE could be used for psoas major MR Elastography.

Phase Unwrapping in Magnetic Resonance Elastography

Phase Unwrapping (PU) is an ill-posed problem in Magnetic Resonance Elastography (MRE). The phase information is not usable until the phases are retrieved by using PU algorithms. In this present study, we attempt to determine the ideal PU method for MRE using both phantom and volunteer psoas major (PM) muscle images. All the MRE experiments were carried out in Philips MRI (Achieva 3.0 T, Best, The Netherlands). A multi-echo gradient-echo MRE pulse sequence was employed and the four PU methods were considered based on their easy user platform. They are namely, Minimum Discontinuity (MD), Laplacian-Based Estimate (LBE), Region Growing (RG) and Dilate-Erode (DE) Propagate. Phantom images were successfully unwrapped by all four methods, whereas MD and LBE could only unwrap PM muscle images properly. RG and DE failed to unwrap the PM muscle images.

Evolving role of magnetic resonance techniques in primary sclerosing cholangitis

Development of non-invasive methods to risk-stratify patients and predict clinical endpoints have been identified as one of the key research priorities in primary sclerosing cholangitis(PSC). In addition to serum and histological biomarkers, there has been much recent interest in developing imaging biomarkers that can predict disease course and clinical outcomes in PSC.Magnetic resonance imaging/magnetic resonance cholangiopancreatography(MRI/MRCP) continue to play a central role in the diagnosis and follow-up of PSC patients. Magnetic resonance(MR) techniques have undergone significant advancement over the last three decades both in MR data acquisition and interpretation. The progression from a qualitative to quantitative approach in MR acquisition techniques and data interpretation, offers the opportunity for the development of objective and reproducible imaging biomarkers that can potentially be incorporated as an additional endpoint in clinical trials. This review article will discuss how the role of MR techniques have evolved over the last three decades from emerging as an alternative diagnostic tool to endoscopic retrograde cholangiopancreatography, to being instrumental in the ongoing search for imaging biomarker of disease stage, progression and prognosis in PSC.

磁共振弹性成像及其在脑疾病中的应用

磁共振弹性成像(magnetic resonance elastography,MRE)是一种通过外界激励将剪切波动传递到所测量的软组织中,采用磁共振成像记录波动位移,并基于波动特征对软组织的力学参量进行估计的方法.脑组织的力学参量,尤其是粘弹参量与其生长、老化和疾病密切相关.本综述首先介绍MRE的理论原理以及软组织粘弹性的物理意义和表示方法,并以脑组织MRE为例说明MRE的技术方法及其扫描过程.其次,针对脑肿瘤和神经退行性疾病等典型的脑疾病,介绍MRE在临床研究中的应用,说明粘弹参量作为脑科学基础研究和疾病诊断的新生物标志物的意义.最后,对MRE在脑疾病和脑科学的应用相关研究热点开展了讨论.

磁共振弹性成像在腹盆部肿瘤中的研究进展

肿瘤力学特性与肿瘤侵袭、进展密切相关,准确评估肿瘤组织硬度对于肿瘤的检测、鉴别诊断、诊疗规划及预后评估具有重要意义。磁共振弹性成像(magnetic resonance elastography,MRE)能量化组织力学特性,无创定量评估组织硬度,进而间接反映组织纤维化程度。本文将对MRE的基本原理、技术发展及其在腹盆部肿瘤中应用的研究现状进行综述,旨在为未来的研究提供新思路,推进MRE的不断成熟,辅助指导临床精准诊疗。

磁共振成像联合超声弹性成像在乳腺良恶性肿瘤鉴别诊断中的价值

目的:分析磁共振成像联合超声弹性成像鉴别诊断乳腺良恶性肿瘤的效果。方法:收集2022年8月—2023年8月聊城市传染病医院收治的98例乳腺肿瘤患者资料开展回顾性分析。患者术前均进行超声弹性成像、磁共振成像检查。以病理诊断结果为金标准,分析超声弹性成像、磁共振成像单一检查与联合检查对乳腺肿瘤的诊断效能;通过Kappa系数评价不同检查方法与病理诊断的一致性。结果:(1)病理诊断结果显示,98例乳腺肿瘤患者中恶性55例(恶性组),良性43例良性(良性组)。超声弹性成像检查中良性组1~3分人数占比高于恶性组,4~5分人数占比低于恶性组(P<0.05)。(2)磁共振成像检查中良性组病灶形态片状、圆形人数占比高于恶性组,边缘毛刺、不规则人数占比低于恶性组(P<0.05)。(3)超声弹性成像、磁共振成像联合检查的灵敏度、准确率、阳性预测值、阴性预测值高于超声弹性成像单一检查(P<0.05)。(4)超声弹性成像诊断与病理诊断一致性尚可(Kappa值=0.508),磁共振成像与病理诊断一致性较好(Kappa值=0.855),联合检查与病理诊断一致性极好(Kappa值=0.896)。结论:乳腺良恶性肿瘤鉴别诊断采取磁共振成像、超声弹性成像联合检查有更理想诊断效能。

肾脏3.0 T多频磁共振弹性成像:解剖区域、生理因素与正常肾脏硬度的关系

目的 应用多频MR弹性成像探讨解剖区域(左肾和右肾,全肾、外皮质、内皮质和髓质)和生理因素(年龄、性别、身体质量指数、饮水情况)与正常肾脏硬度的关系。材料与方法 2023年3月至2023年12月在深圳市中医院招募97名健康志愿者,入组92名受试者,应用3.0 T MR进行多频弹性成像,测量左右侧全肾、外皮质、内皮质及髓质的硬度,比较左右侧不同解剖区域硬度差异,分析年龄、身体质量指数与肾脏硬度的相关性及男女性之间、不同年龄组之间肾脏硬度的差异,最后比较其中18名健康志愿者饮水前后肾脏硬度的变化。结果 左右侧全肾、外皮质、内皮质和髓质的硬度差异无统计学意义(P≥0.05),而肾脏内部不同解剖区域的硬度差异具有统计学意义,其中内皮质最硬[(3.01±0.22)m/s],其次是外皮质[(2.69±0.20)m/s]和全肾[(2.55±0.17)m/s],最后是髓质[(2.16±0.15)m/s]。全肾(r=-0.301,P=0.004)及内皮质(r=-0.330,P=0.001)硬度随年龄增长而轻度降低,并且在三个年龄组之间差异具有统计学意义(P<0.05)。男性肾脏内部不同解剖区域硬度均稍高于女性(P<0.05)。男性和女性饮水后肾脏内部不同解剖区域硬度均高于饮水前(P<0.05),其中外皮质及内皮质增加较明显。结论肾脏硬度存在解剖区域性差异,并且与年龄、性别和饮水情况存在关系。

磁共振小肠造影技术在小肠疾病诊断中的图像质量控制研究

目的:探讨磁共振小肠造影(MRE)技术在小肠疾病诊断中的图像质量控制,分析影响MRE成像质量因素,通过采取质量控制措施而提高MRE成像质量。方法:回顾性分析2018年5月至2023年3月联勤保障部队第九〇〇医院收治的167例小肠病变患者MRE检查资料,对所有患者临床及影像检查结束后的图像质量进行评估,分析成像质量不满足诊断要求的原因,制定质量控制措施。结果:在167例小肠病变患者中,MRE图像可满足诊断要求的患者153例(占91.62%)。MRE图像无法满足诊断要求的患者14例(占8.38%),其中原因为呼吸配合差3例(占1.80%),图像磁敏感伪影较重2例(占1.20%),由于肠道蠕动厉害导致图像模糊1例(占0.60%),由于肠道蠕动肠腔内部产生流空效应而无法满足诊断要求2例(占1.20%),充盈口服对比剂欠佳而导致肠管未完全扩张开4例(占2.40%),未做好肠道准备而导致残留物较多2例(占1.20%)。针对MRE图像无法满足诊断要求的因素制定以下质量控制措施:①选择安全性好、无严重不良反应及可充分扩张肠腔的双相对比剂;②对患者做好肠管扩张,抑制肠道蠕动,并进行呼吸训练;③进行冠状位大视野扫描,以显示肠道全景影像;④对病灶进行轴位常规解剖序列和功能成像序列扫描。结论:MRE技术在小肠疾病诊断的图像质量控制中应选择合适的对比剂,做好患者的检查前准备,使用腔内对比剂、进行肠道扩张和最佳成像技术等对于获得高质量的肠道图像至关重要。

磁共振及超声瞬时弹性成像对代谢相关脂肪性肝病定量评估的研究进展

代谢相关脂肪性肝病(MAFLD)会导致脂肪性肝炎、肝硬化及肝细胞性癌。肝穿刺是诊断MAFLD的金标准。然而,有创检查不能广泛应用于临床实践中,无创诊断MAFLD是未来发展趋势。目前主要的检查方法有超声瞬时弹性成像、磁共振质子密度脂肪分数、磁共振波谱成像、磁共振弹性成像等。因此,本文就MRI及超声瞬时弹性成像技术在MAFLD定量评估中的研究进展进行综述,旨在为临床精准诊疗提供影像标记物。

3.0T MRI联合经阴道超声弹性成像技术在子宫肌瘤及子宫腺肌病诊断中的应用价值

目的:探讨3.0T核磁共振成像(MRI)联合经阴道超声弹性成像技术在子宫肌瘤及子宫腺肌病诊断中的应用价值。方法:回顾性分析2021年1月至2022年1月期间华北医疗健康集团峰峰总医院收治的56例子宫肌瘤和41例子宫腺肌病患者,所有患者均行3.0T MRI检查和经阴道超声弹性成像技术检查,以病理诊断为“金标准”,比较MRI、经阴道超声弹性成像技术和两者联合的诊断结果,记录不同检查方法的诊断情况,并分析总符合率,计算灵敏度、特异度和准确率。结果:3.0T MRI联合经阴道超声弹性成像检查子宫肌瘤的诊断总符合率为96.43%,MRI诊断的总符合率为75.00%,经阴道超声诊断的总符合率为80.36%,联合、单独检测的总符合率差异均有统计学意义(x^(2)=10.500、7.049,P<0.05);MRI联合经阴道超声弹性成像检查子宫腺肌病的诊断总符合率为97.56%,显著高于MRI(78.05%)和经阴道超声弹性成像(78.05%)单独检查,差异有统计学意义(x^(2)=7.289、7.289,P<0.05);MRI、超声阴道弹性成像技术单独检测及联合检测子宫肌瘤的灵感度分别为71.74%、78.26%及95.62%,特异度分别为90.00%、90.00%及100.00%,准确率分别为75.00%、80.36%及96.43%,其灵敏度及准确率联合检测明显高于MRI单独检测(x^(2)=5.029、10.500,P<0.05),联合检测的准确率明显高于阴道超声单独检测(x^(2)=7.049,P<0.05);MRI、超声阴道弹性成像技术单独检测及联合检测子宫腺肌病的灵感度分别为81.25%、78.73%及96.88%,特异度分别为66.67%、77.78%及100.00%,准确率分别为78.05%、78.05%及97.56%;联合检测的准确率明显高于MRI和阴道超声单独检测,差异有统计学意义(x^(2)=7.289、7.289,P<0.05)。结论:3.0T MRI联合经阴道超声弹性成像技术在子宫肌瘤及子宫腺肌病中确诊率更高,有较好的诊断价值,能为临床医生治疗提供可靠的参考资料。

多模态影像技术对大鼠肝纤维化评估的实验研究

目的:探讨多模态影像技术对大鼠肝纤维化(HF)的评估价值。方法:选取健康雄性(SD)大鼠48只,采用随机数表法将其均分为对照组、M1模型组、M2模型组和M3模型组,共4组,每组12只。M1、M2和M3模型组采用四氯化碳(CCl4)加乙醇复合法进行诱导,制备肝纤维化模型。分别在造模第4、6和8周时,M1模型组进行超声检测,M2模型组进行动态增强磁共振影像(DCE-MRI)检测,M3模型组采用常规超声、超声弹性成像联合DCE-MRI技术检测。对照组大鼠随机分为3组,每组4只,分别与M1、M2、M3组大鼠进行对照。影像检查结束后取肝组织行HE染色,观察模型组大鼠肝脏纤维化的程度。采用常规超声观察大鼠肝脏形态,测量门静脉主干内径。彩色多普勒测量门静脉血流速度。超声弹性观察肝实质硬度颜色分布、测量肝脏实质的弹性值。采用受试者工作特征(ROC)初始曲线下面积(iAUC)分析DCE-MRI检查中血流动力参数容量转运常数(Ktrans)、速率常数(Kep)和血管外细胞外间隙体积百分数(Ve)的诊断效能。结果:常规超声显示,对照组大鼠肝脏无异常变化,M1组大鼠肝脏形态发生改变。超声弹性成像显示:M1组大鼠肝脏弹性值(33.16kPa)随着纤维化程度的加重而呈上升趋势,且高于对照组(13.11kPa)。M2组常规MRI显示:对照组大鼠肝脏形态正常,M2组中,造模6与8周大鼠较4周大鼠肝脏形态改变更明显。DCE-MRI结果中的ROC曲线分析显示,Ktrans与Ve对肝纤维化具有较高的诊断效能,其iAUC均>0.9。M1模型组、M2模型组、M3模型组大鼠进行组间比较,多模态影像技术对大鼠早期肝纤维化诊断的灵敏度、准确率、阳性预测值、阴性预测值均高于单独的检查手段,差异有统计学意义(χ^(2)=0.634、0.644、0.621、0.543,P<0.05)。HE染色结果显示,模型组大鼠肝组织出现不同程度的纤维增生。结论:多模态影像技术可以作为评价肝脏纤维化的有效检测方法。

Elastography-based screening for esophageal varices in patients with advanced chronic liver disease

Elastography-based liver stiffness measurement(LSM) is a non-invasive tool for estimating liver fibrosis but also provides an estimate for the severity of portal hypertension in patients with advanced chronic liver disease(ACLD). The presence of varices and especially of varices needing treatment(VNT) indicates distinct prognostic stages in patients with compensated ACLD(cACLD). The Baveno VI guidelines suggested a simple algorithm based on LSM < 20 kPa(by transient elastography, TE) and platelet count > 150 G/L for ruling-out VNT in patients with cACLD. These(and other) TE-based LSM cut-offs have been evaluated for VNT screening in different liver disease etiologies. Novel point shear-wave elastography(pSWE) and two-dimensional shear wave elastography(2D-SWE) methodologies for LSM have also been evaluated for their ability to screen for "any" varices and for VNT. Finally, the measurement of spleen stiffness(SSM) by elastography(mainly by pSWE and 2D-SWE) may represent another valuable screening tool for varices. Here, we summarize the current literature on elastography-based prediction of "any" varices and VNT. Finally,we have summarized the published LSM and SSM cut-offs in clinically useful scale cards.

Assessing significant fibrosis using imaging-based elastography in chronic hepatitis B patients: Pilot study

BACKGROUND Accurate detection of significant fibrosis(fibrosis stage 2 or higher on the METAVIR scale)is important especially for chronic hepatitis B(CHB)patients with high viral loads but with normal or mildly elevated alanine aminotransferase(ALT)levels because the presence of significant fibrosis is accepted as the indication for antiviral treatment.Liver biopsy is the reference standard for diagnosing significant fibrosis,but it is an invasive procedure.Consequently,noninvasive imaging-based measurements,such as magnetic resonance elastography(MRE)or two-dimensional shear-wave elastography(2DSWE),have been proposed for the quantitative assessment of liver fibrosis.AIM To explore MRE and 2D-SWE to identify fibrosis stage,and to compare their performance with that of serum-based indices.METHODS The study enrolled 63 treatment-na?ve CHB patients with high viral loads but with normal or mildly elevated ALT levels who underwent liver biopsy before a decision was made to initiate antiviral therapy.MRE and 2D-SWE were performed,and serum-based indices,such as FIB-4 and aspartate transaminase to platelet ratio index(APRI),were calculated.The diagnostic performances of MRE,2D-SWE,FIB-4,and APRI for assessing significant fibrosis(≥F2)and cirrhosis(F4)were evaluated with liver histology as the reference standard,using receiver operating characteristic analyses.RESULTS The liver fibrosis stage was F0/F1 in 19,F2 in 14,F3 in 14,and F4 in 16 patients,respectively.MRE significantly discriminated F2 from F0/1(P=0.022),whereas 2D-SWE showed a broad overlap in distinguishing those stages.MRE showed a higher correlation coefficient value with fibrosis stage than 2D-SWE with fibrosis stage(0.869 vs 0.649,Spearman test;P<0.001).Multivariate linear regression analyses showed that fibrosis stage was the only factor affecting the values of MRE(P<0.001),whereas body mass index(P=0.042)and fibrosis stage(P<0.001)were independent factors affecting 2D-SWE values.MRE performance for diagnosing significant fibrosis was better[area under the curve(AUC)=0.906,positive predictive value(PPV)97.3%,negative predictive value(NPV)69.2%]than that of FIB-4(AUC=0.697,P=0.002)and APRI(AUC=0.717,P=0.010),whereas the performance of 2D-SWE(AUC=0.843,PPV 86%,NPV 65%)was not significantly different from that of FIB-4 or APRI.CONCLUSION Compared to SWE,MRE might be more precise non-invasive assessment for depicting significant fibrosis and for making-decision to initiate antiviral-therapy in treatment-na?ve CHB patients with normal or mildly-elevated ALT levels.