Radiomics model based on preoperative gadoxetic acid-enhanced MRI for predicting liver failure

BACKGROUND Postoperative liver failure is the most severe complication in cirrhotic patients with hepatocellular carcinoma(HCC) after major hepatectomy. Current available clinical indexes predicting postoperative residual liver function are not sufficiently accurate.AIM To determine a radiomics model based on preoperative gadoxetic acid-enhanced magnetic resonance imaging for predicting liver failure in cirrhotic patients with HCC after major hepatectomy.METHODS For this retrospective study, a radiomics-based model was developed based on preoperative hepatobiliary phase gadoxetic acid-enhanced magnetic resonance images in 101 patients with HCC between June 2012 and June 2018. Sixty-one radiomic features were extracted from hepatobiliary phase images and selected by the least absolute shrinkage and selection operator method to construct a radiomics signature. A clinical prediction model, and radiomics-based model incorporating significant clinical indexes and radiomics signature were built using multivariable logistic regression analysis. The integrated radiomics-based model was presented as a radiomics nomogram. The performances of clinical prediction model, radiomics signature, and radiomics-based model for predicting post-operative liver failure were determined using receiver operating characteristics curve, calibration curve, and decision curve analyses.RESULTS Five radiomics features from hepatobiliary phase images were selected to construct the radiomics signature. The clinical prediction model, radiomics signature, and radiomics-based model incorporating indocyanine green clearance rate at 15 min and radiomics signature showed favorable performance for predicting postoperative liver failure(area under the curve: 0.809-0.894). The radiomics-based model achieved the highest performance for predicting liver failure(area under the curve: 0.894; 95%CI: 0.823-0.964). The integrated discrimination improvement analysis showed a significant improvement in the accuracy of liver failure prediction when radiomics signature was added to the clinical prediction model(integrated discrimination improvement = 0.117, P =0.002). The calibration curve and an insignificant Hosmer-Lemeshow test statistic(P = 0.841) demonstrated good calibration of the radiomics-based model. The decision curve analysis showed that patients would benefit more from a radiomics-based prediction model than from a clinical prediction model and radiomics signature alone.CONCLUSION A radiomics-based model of preoperative gadoxetic acid–enhanced MRI can be used to predict liver failure in cirrhotic patients with HCC after major hepatectomy.     

Differentiating autoimmune pancreatitis from pancreatic ductal adenocarcinoma with CT radiomics features

PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%.     

Ependymoma and pilocytic astrocytoma: Differentiation using radiomics approach based on machine learning

Mandatory accurate and specific diagnosis demands have brought about increased challenges for radiologists in pediatric posterior fossa tumor prediction and prognosis. With the development of high-performance computing and machine learning technologies, radiomics provides increasing opportunities for clinical decision-making. Several studies have applied radiomics as a decision support tool in intracranial tumors differentiation. Here we seek to achieve preoperative differentiation between ependymoma (EP) and pilocytic astrocytoma (PA) using radiomics analysis method based on machine learning. A total of 135 Magnetic Resonance Imaging (MRI) slices are divided into training sets and validation sets. Three kinds of radiomics features, including Gabor transform, texture and wavelet transform based ones are used to obtain 300 multimodal features. Kruskal–Wallis test score (KWT) and support vector machines (SVM) are applied for feature selection and tumor differentiation. The performance is investigated via accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) analysis. Results show that the accuracy, sensitivity, specificity, and AUC of the selected feature set are 0.8775, 0.9292, 0.8000, and 0.8646 respectively, having no significant differences compared with the overall feature set. For different types of features, texture features yield the best differentiation performance and the significance analysis results are consistent with this. Our study demonstrates texture features perform better than the other features. The radiomics approach based on machine learning is efficient for pediatric posterior fossa tumors differentiation and could enhance the application of radiomics methods for assisted clinical diagnosis.     

Artificial intelligence in liver ultrasound

Artificial intelligence (AI) is playing an increasingly important role in medicine, especially in the field of medical imaging. It can be used to diagnose diseases and predict certain statuses and possible events that may happen. Recently, more and more studies have confirmed the value of AI based on ultrasound in the evaluation of diffuse liver diseases and focal liver lesions. It can assess the severity of liver fibrosis and nonalcoholic fatty liver, differentially diagnose benign and malignant liver lesions, distinguish primary from secondary liver cancers, predict the curative effect of liver cancer treatment and recurrence after treatment, and predict microvascular invasion in hepatocellular carcinoma. The findings from these studies have great clinical application potential in the near future. The purpose of this review is to comprehensively introduce the current status and future perspectives of AI in liver ultrasound.     

Recent advances in the diagnostic evaluation of pancreatic cystic lesions

Pancreatic cystic lesions (PCLs) are becoming more prevalent due to more frequent abdominal imaging and the increasing age of the general population. It has become crucial to identify these PCLs and subsequently risk stratify them to guide management. Given the high morbidity associated with pancreatic surgery, only those PCLs at high risk for malignancy should undergo such treatment. However, current diagnostic testing is suboptimal at accurately diagnosing and risk stratifying PCLs. Therefore, research has focused on developing new techniques for differentiating mucinous from non-mucinous PCLs and identifying high risk lesions for malignancy. Cross sectional imaging radiomics can potentially improve the predictive accuracy of primary risk stratification of PCLs at the time of detection to guide invasive testing. While cyst fluid glucose has reemerged as a potential biomarker, cyst fluid molecular markers have improved accuracy for identifying specific types of PCLs. Endoscopic ultrasound guided approaches such as confocal laser endomicroscopy and through the needle microforceps biopsy have shown a good correlation with histopathological findings and are evolving techniques for identifying and risk stratifying PCLs. While most of these recent diagnostics are only practiced at selective tertiary care centers, they hold a promise that management of PCLs will only get better in the future.     

基于动态增强MRI影像组学评分和激素受体的列线图预测乳腺癌新辅助化疗不敏感的价值

目的 探讨基于动态增强MRI（DCE-MRI）影像组学评分（Radscore）和激素受体状态的列线图预测乳腺癌新辅助化疗（NAC）疗效不敏感的价值。 方法 回顾性收集128例行乳腺癌NAC治疗的女性病人,平均年龄（49.2±10.0）岁。128例病人按照7∶3比例随机分为训练集90例（疗效敏感者47例,疗效不敏感者43例）和测试集38例（疗效敏感者15例,疗效不敏感者23例）。基于DCE-MRI影像提取并筛选影像组学特征,采用多因素逻辑回归构建影像组学模型并计算模型的Radscore。采用t检验、χ²检验或Fisher确切概率检验比较训练集和测试集中临床病理指标[年龄、雌激素受体（ER）、孕激素受体（PR）、人表皮生长因子受体-2（HER-2）和肿瘤增殖细胞核抗原-67（Ki-67）],将差异有统计学意义的临床病理指标和Radscore纳入多因素逻辑回归,建立联合模型和列线图。应用受试者操作特征（ROC）曲线下面积（AUC）评价影像组学模型和联合模型的预测效能。应用决策曲线评估影像组学模型和联合模型的临床应用价值。 结果 在训练集中,ER和PR在疗效敏感与不敏感组间的差异均有统计学意义（均P<0.05）,但未得到测试集的验证（均P>0.05）。在训练集中,联合模型预测NAC不敏感的AUC值和准确度分别高于影像组学模型约3.8%和3.1%。在测试集中,联合模型预测NAC不敏感的AUC值高于影像组学模型,其较后者提高了约2.3%,但两者的准确度相同。在基于ER、PR和Radscore构建的联合模型列线图中,Radscore得分最高,其次是ER和PR。决策曲线分析显示联合模型的临床获益高于影像组学模型。 结论 基于DCE-MRI的Radscore和ER、PR构建的联合模型列线图能够较好地预测NAC疗效不敏感。     

基于增强CT影像组学列线图预测单发肝细胞癌GPC3表达状态

目的 探讨增强CT影像组学列线图在鉴别单发肝细胞癌（HCC）磷脂酰肌醇蛋白聚糖3（GPC3）表达中的价值。方法 回顾性收集来自2个医疗机构共152例单发HCC病人的临床及影像资料,所有病人均行上腹部增强CT扫描并记录GPC3表达水平。天津市第一中心医院的106例病人资料作为训练集（GPC3阳性83例、阴性23例）,天津医科大学肿瘤医院的46例病人资料作为验证集（GPC3阳性35例、阴性11例）。对所有病人术前1个月内增强CT影像进行影像组学特征提取。在训练集中,对所有影像组学特征进行降维并得到最优子集,计算影像组学评分（Radscore）;比较GPC3阳性组和阴性组间临床资料[包括血清甲胎蛋白（AFP）、糖类抗原199（CA199）等]的差异,将差异有统计学意义的指标进行二元logistic回归分析,获得GPC3阳性的独立预测因素。将获得的临床信息及Radscore分别建立临床列线图、影像组学列线图及联合列线图。采用受试者操作特征曲线下面积（AUC）分析各列线图对GPC3表达状态的预测能力,采用DeLong检验比较各列线图间的诊断效能,并用决策曲线分析评估列线图的临床价值。使用验证集数据对列线图预测效能进行验证。结果 二元logistic回归显示血清AFP、CA199、Radscore是GPC3阳性的独立危险因素[优势比（OR）分别为8.503、1.090、13 300.044,均P<0.05]。校准曲线显示联合列线图对GPC3阳性表达的预测概率与实际概率一致性良好。训练集中,联合列线图的AUC（0.918）高于影像组学列线图（0.842）和临床列线图（0.787）（均P<0.05）,联合列线图的敏感度最高,而临床列线图的特异度最高;验证集中,联合列线图的AUC（0.896）高于影像组学列线图（0.726）和临床列线图（0.803）（均P<0.05）,联合列线图的敏感度和特异度均最高。决策曲线分析显示当阈值概率处于16%~86%时,联合列线图的临床净获益高于临床列线图和影像组学列线图。结论 基于增强CT的影像组学列线图可以术前鉴别单发HCC GPC3阳性和阴性表达,联合列线图进一步提高了预测效能。     

基于CT平扫的影像组学模型鉴别肺炎性肌纤维母细胞瘤和周围型肺癌的研究

目的探讨基于CT平扫的影像组学在鉴别肺炎性肌纤维母细胞瘤(IMT)和周围型肺癌(PLC)的价值。方法回顾性收集经我院及外院手术后病理证实的72例肺IMT及79例PLC的资料。使用A.K(Artificial Intelligence Kit)软件从CT平扫图像中提取高通量数据,对其进行特征筛选及降维,去除了重复性差、冗余度高的特征。将数据按照7∶3∶3比例分为训练集、验证集及测试集,其中外院数据作为测试集。采用逻辑回归、支持向量机、随机森林机器算法对所提取较优特征建立分类预测模型,绘制受试者操作曲线(ROC),计算受试者操作曲线下面积(AUC),评估模型的诊断预测效能,采用Delong检验比较模型间的效能差异。采用测试集对三种机器学习模型进行评估,并绘制ROC曲线。结果共提取396纹理特征,通过特征选择及降维获得12个较优的纹理特征,三种分类模型符合率分别为77.1%、62.9%、82.9%,特异度分别为61.1%、55.6%、83.3%,敏感度分别为94.1%、70.6%、72.4%,AUC值分别为0.791、0.748、0.859,Delong检验比较模型间ROC-AUC值无统计学意义,随机森林符合率(82.9%)更高。测试集三种模型AUC值分别为0.807、0.739、0.781。结论基于CT平扫建立的影像组学特征模型有助于区分肺IMT和PLC,为临床准确诊断和个体化治疗提供客观依据。