Myocardial tissue remodeling in early adult obesity and its association with regional adipose tissue distribution and ectopic fat deposits: a prospective study.

OBJECTIVES: To evaluate the left ventricular (LV) myocardial tissue characteristics in early adult obesity and its association with regional adipose tissue and ectopic fat deposition. METHODS: Forty-nine obese adults (mean body mass index: 29.9 ± 2.0 kg/m2) and 44 healthy controls were prospectively studied. LV native and post-contrast T1 values, extracellular volume fraction (ECV), regional adipose tissue (epicardial, visceral, and subcutaneous adipose tissue (EAT, VAT, and SAT)), and ectopic fat deposition (hepatic and pancreatic proton density fat fractions (H-PDFF and P-PDFF)) based on magnetic resonance imaging were compared. The association was assessed by multivariable linear regression. RESULTS: The obese participants showed reduced global ECV compared to the healthy controls (p < 0.05), but there was no significant difference in global native or post-contrast T1 values between the two groups. Additionally, the obese individuals exhibited higher EAT, VAT, SAT, H-PDFF, and P-PDFF than the controls (p < 0.05). ECV was associated with insulin resistance, dyslipidemia, and systolic blood pressure (SBP) (p < 0.05). Multiple linear regression demonstrated that H-PDFF and SAT were independently associated with ECV in entire population (ß = - 0.123 and - 0.012; p < 0.05). CONCLUSIONS: Reduced myocardial ECV in patients with mild-to-moderate obesity and its relationship to SBP may indicate that cardiomyocyte hypertrophy, rather than extracellular matrix expansion, is primarily responsible for myocardial tissue remodeling in early adult obesity. Our findings further imply that H-PDFF and SAT are linked with LV myocardial tissue remodeling in this cohort beyond the growth difference and cardiovascular risk factors. CLINICAL TRIALS REGISTRATION: Effect of lifestyle intervention on metabolism of obese patients based on smart phone software (ChiCTR1900026476). CLINICAL RELEVANCE STATEMENT: Myocardial fibrosis in severe obesity predicts poor prognosis. We showed that cardiomyocyte hypertrophy, not myocardial fibrosis, is the main myocardial tissue characteristic of early obesity. This finding raises the possibility that medical interventions, like weight loss, may prevent cardiac fibrosis. KEY POINTS: • Myocardial tissue characteristics in early adult obesity are unclear. • Myocardial extracellular volume fraction (ECV) can be quantitatively evaluated using T1 mapping based on cardiac magnetic resonance imaging (MRI). • Cardiac MRI-derived ECV may noninvasively evaluate myocardial tissue remodeling in early adult obesity.

Feasibility of using software-aided selection of virtual monoenergetic level for optimal image quality of acute necrotising pancreatitis based on dual-energy computed tomography: a preliminary study.

OBJECTIVE: This study aimed to assess the feasibility of software-aided selection of monoenergetic level for acute necrotising pancreatitis (ANP) depiction compared to other automatic image series generated using dual-energy computed tomography (CT). METHODS: The contrast-enhanced dual-source dual-energy CT images in the portal venous phase of 48 patients with ANP were retrospectively analysed. Contrast-to-noise ratio (CNR) of pancreatic parenchyma-to-necrosis, signal-to-noise ratio (SNR) of the pancreas, image noise, and score of subjective diagnosis were measured, calculated, and compared among the CT images of 100 kV, Sn140 kV, weighted-average 120 kV, and optimal single-energy level for CNR. RESULTS: CNR of pancreatic parenchyma-to-necrosis in the images of 100 kV, Sn140 kV, weighted-average 120 kV, and the optimal single-energy level for CNR was 5.18 ± 2.39, 3.13 ± 1.35, 5.69 ± 2.35, and 9.99 ± 5.86, respectively; SNR of the pancreas in each group was 6.31 ± 2.77, 4.27 ± 1.56, 7.21 ± 2.69, and 11.83 ± 6.30, respectively; image noise in each group was 18.78 ± 5.20, 17.79 ± 4.63, 13.28 ± 3.13, and 9.31 ± 2.96, respectively; and score of subjective diagnosis in each group was 3.56 ± 0.50, 3.00 ± 0.55, 3.48 ± 0.55, and 3.88 ± 0.33, respectively. The four measurements of the optimal single-energy level for CNR images were significantly different from those of images in the other three groups (P < 0.05). CNR of pancreatic parenchyma-to-necrosis, SNR of the pancreas, and score of subjective diagnosis in the images of the optimal single-energy level for CNR were significantly higher, while the image noise was lower than those in the other three groups (all P = 0.000). CONCLUSION: Optimal single-energy level imaging for CNR of dual-source CT could improve quality of CT images in patients with ANP, enhancing the display of necrosis in the pancreas.

Association of abdominal adiposity, hepatic shear stiffness with subclinical left-ventricular remodeling evaluated by magnetic resonance in adults free of overt cardiovascular diseases: a prospective study.

BACKGROUND: Abdominal ectopic fat deposition and excess visceral fat depots in obesity may be related to cardiovascular disease (CVD) as both are involved in the metabolic syndrome (MetS). The awareness of the link between abdominal adiposity and subclinical cardiac remodeling would help improve treatment and outcome. Besides, liver fibrosis has also shown a potential relationship with cardiac dysfunction. Thus, we aimed to investigate the associations of magnetic resonance (MR)-based abdominal adiposity and hepatic shear stiffness with subclinical left ventricular (LV) remodeling while taking account of MetS-related confounders in adults free of overt CVD. METHODS: This was an exploratory, prospective study of 88 adults (46 subjects with obesity, 42 healthy controls) who underwent 3 T cardiac and body MR exams. Measures of abdominal MR included hepatic and pancreatic proton density fat fraction (H-PDFF and P-PDFF), hepatic shear stiffness by MR elastography, and subcutaneous and visceral adipose tissue (SAT and VAT). Cardiac measures included epicardial adipose tissue (EAT) and parameters of LV geometry and function. Associations were assessed using Pearson correlation and multivariable linear regression analyses, in which age, sex, and MetS-related confounders were adjusted for. RESULTS: The LV ejection fractions of all participants were within the normal range. Higher H-PDFF, P-PDFF, SAT and VAT were independently associated with lower LV global myocardial strain parameters (radial, circumferential and longitudinal peak strain [PS], longitudinal peak systolic strain rate and diastolic strain rate) (ß = - 0.001 to - 0.41, p < 0.05), and P-PDFF, SAT and VAT were independently and positively associated with LV end-diastolic volume and stroke volume (ß = 0.09 to 3.08, p ≤ 0.02) in the over-all cohort. In the obesity subgroup, higher P-PDFF and VAT were independently associated with lower circumferential and longitudinal PS, respectively (ß = - 0.29 to - 0.05, p ≤ 0.01). No independent correlation between hepatic shear stiffness and EAT or LV remodeling was found (all p ≥ 0.05). CONCLUSIONS: Ectopic fat depositions in the liver and pancreas, and excess abdominal adipose tissue pose a risk of subclinical LV remodeling beyond MetS-related CVD risk factors in adults without overt CVD. VAT may play a more considerable role as a risk factor for subclinical LV dysfunction than does SAT in individuals with obesity. The underlying mechanisms of these associations and their longitudinal clinical implications need further investigation.

Intravoxel incoherent motion diffusion weighted imaging for preoperative evaluation of liver regeneration after hepatectomy in hepatocellular carcinoma.

OBJECTIVES: To explore whether intravoxel incoherent motion (IVIM) parameters could evaluate liver regeneration preoperatively. METHODS: A total of 175 HCC patients were initially recruited. The apparent diffusion coefficient, true diffusion coefficient (D), pseudodiffusion coefficient (D*), pseudodiffusion fraction (f), diffusion distribution coefficient, and diffusion heterogeneity index (Alpha) were measured by two independent radiologists. Spearman's correlation test was used to assess correlations between IVIM parameters and the regeneration index (RI), calculated as 100% × (the volume of the postoperative remnant liver - the volume of the preoperative remnant liver) / the volume of the preoperative remnant liver. Multivariate linear regression analyses were used to identify the factors for RI. RESULTS: Finally, 54 HCC patients (45 men and 9 women, mean age 51.26 ± 10.41 years) were retrospectively analyzed. The intraclass correlation coefficient ranged from 0.842 to 0.918. In all patients, fibrosis stage was reclassified as F0-1 (n = 10), F2-3 (n = 26), and F4 (n = 18) using the METAVIR system. Spearman correlation test showed D* (r = 0.303, p = 0.026) was associated with RI; however, multivariate analysis showed that only D value was a significant predictor (p < 0.05) of RI. D and D*showed moderate correlations with fibrosis stage (r = -0.361, p = 0.007; r = -0.457, p = 0.001). Fibrosis stage showed a negative correlation with RI (r = -0.263, p = 0.015). In the 29 patients who underwent minor hepatectomy, only the D value showed a positive association (p < 0.05) with RI, and a negative correlation with fibrosis stage (r = -0.360, p = 0.018). However, in the 25 patients who underwent major hepatectomy, no IVIM parameters were associated with RI (p > 0.05). CONCLUSIONS: The D and D* values, especially the D value, may be reliable preoperative predictors of liver regeneration. KEY POINTS: • The D and D* values, especially the D value, derived from IVIM diffusion-weighted imaging may be useful markers for the preoperative prediction of liver regeneration in patients with HCC. • The D and D* values derived from IVIM diffusion-weighted imaging show significant negative correlations with fibrosis, an important predictor of liver regeneration. • No IVIM parameters were associated with liver regeneration in patients who underwent major hepatectomy, but the D value was a significant predictor of liver regeneration in patients who underwent minor hepatectomy.

Predictive models and early postoperative recurrence evaluation for hepatocellular carcinoma based on gadoxetic acid-enhanced MR imaging.

BACKGROUND: The prognosis of hepatocellular carcinoma (HCC) is still poor largely due to the high incidence of recurrence. We aimed to develop and validate predictive models of early postoperative recurrence for HCC using clinical and gadoxetic acid-enhanced magnetic resonance (MR) imaging-based findings. METHODS: In this retrospective case-control study, 209 HCC patients, who underwent gadoxetic acid-enhanced MR imaging before curative-intent resection, were enrolled. Boruta algorithm and backward stepwise selection with Akaike information criterion (AIC) were used for variables selection Random forest, Gradient-Boosted decision tree and logistic regression model analysis were used for model development. The area under the receiver operating characteristic curve (AUC), calibration plots, and decision curve analysis were used to evaluate model's performance. RESULTS: One random forest model with Boruta algorithm (RF-Boruta) was developed consisting of preoperative serum ALT and AFP levels and six MRI findings, while preoperative serum AST and AFP levels and four MRI findings were included in one logistic regression model with backward stepwise selection method (Logistic-AIC).The two predictive models demonstrated good discrimination performance in both the training set (RF-Boruta: AUC, 0.820; Logistic-AIC: AUC, 0.853), internal validation set (RF-Boruta: AUC, 0.857, Logistic-AIC: AUC, 0.812) and external validation set(RF-Boruta: AUC, 0.805, Logistic-AIC: AUC, 0.789). Besides, in both the internal validation and external validation sets, the RF-Boruta model outperformed Barcelona Clinic Liver Cancer (BCLC) stage (p < 0.05). CONCLUSIONS: The RF-Boruta and Logistic-AIC models with good prediction performance for early postoperative recurrence may lead to optimal and comprehensive treatment approaches, and further improve the prognosis of HCC after resection.

Preoperative evaluation of liver regeneration following hepatectomy in hepatocellular carcinoma using magnetic resonance elastography.

Background: For patients with hepatocellular carcinoma (HCC) undergoing hepatectomy, insufficient remnant liver regenerative capacity can lead to liver failure. The aim of this study was to evaluate the potential role of magnetic resonance elastography (MRE) for the preoperative prediction of liver regeneration in patients with HCC after partial hepatectomy (PH). Methods: A total of 54 patients with HCC undergoing MRE prior to PH were retrospectively included. The total functional liver, volume of preoperative future liver remnant (LVpre), and volume of postoperative liver remnant (LVpost), respectively, were measured, and the regeneration index (RI) and parenchymal hepatic resection rate (PHRR) were manually calculated. Univariate and multivariate logistic regression analyses were conducted to identify factors associated with a high RI, and receiver operating characteristic (ROC) curves were employed to evaluate the diagnostic performance of the liver stiffness (LS) values. Patients were classified into three subgroups based on the value of PHRR: low PHRR (<30%), intermediate PHRR (30-50%), and high PHRR (>50%). Subsequently, Spearman correlation analysis was used to investigate the relationship between LS values and RI in the subgroups. Results: Multivariable analysis revealed a low LS value was associated with greater odds of a high RI [odds ratio (OR), 0.049; 95% confidence interval (CI): 0.002 to 0.980]. An optimal cutoff value of 3.30 kPa was used to divide all patients into a low RI group and a high RI group with an area under the curve (AUC) value of 0.882 (95% CI: 0.767 to 0.996). A significant negative relationship between RI and LS values (r=-0.799; P<0.001) was observed in the intermediate PHRR subgroup. Conclusions: The LS values based on MRE may serve as a potential preoperative predictor of liver regeneration for patients with HCC undergoing PH.

Using arterial phase hyperenhancement on CT instead of gadoxetic acid arterial phase enhancement may improve the diagnostic performance for hepatocellular carcinoma.

Background: The diagnostic performance for hepatocellular carcinoma (HCC) is hampered using gadoxetic acid-enhanced magnetic resonance (MR) imaging due to the high incidence of transient severe motion in arterial phase (AP). Dynamic contrast enhanced computed tomography (CT) imaging yield high detection rate for hepatic nodules in AP, and the combined use of CT arterial phase (CTAP) imaging with gadoxetic acid-enhanced MR imaging may improve the diagnostic performance for HCC. Thus, this study aimed to determine whether the combined use of CTAP and gadoxetic acid-enhanced MR imaging can improve the diagnostic performance for HCC based on various imaging diagnostic criteria. Methods: A total of 169 surgically histologically confirmed hepatic nodules (137 HCCs and 32 non-HCC-nodules) were retrospectively enrolled. Two different imaging protocol sets were reviewed: (I) full gadoxetic acid-enhanced magnetic resonance imaging (MRI) sequences; and (II) CTAP imaging combined with the gadoxetic acid-enhanced MRI but excluding the MR imaging AP images. Three independent reviewers followed the 2018 Liver Reporting and Data System (LI-RADS), European Association for the Study of the Liver (EASL), and 2018 Korean guidelines to characterize these heaptic nodules by reviewing the two imaging protocol sets and the diagnostic peformance were compared by using McNemar test. Results: The detection rate of AP hyperenhancement (APHE) was higher in CTAP than in the MR arterial phase (MRAP) for hepatic nodules (87.57% vs. 75.15%) and HCCs (97.08% vs. 82.48%) (all P<0.001). For the LI-RADS criteria, the Protocol-II increased the sensitivity to 75.91% from 70.80% of Protocol-I (P=0.016), with a minimal decrease of the specificity to 71.88% from 75.00% (P=1.000). For the EASL criteria, the numerical increases were found of Protocol-II than Protocol-I in both sensitivity (81.02% vs. 78.10%) and specificity (75.00% vs.71.88%), but with no statistical significance. For the Korean criteria, the Protocol-II increased the sensitivity to 94.89% from 83.21% of Protocol-I (P<0.001). The specificity increased to 65.63% from 62.50%, with no statistical significance (P=1.000). Conclusions: Using CTAP instead of gadoxetic acid-enhanced MRAP can improve the diagnostic sensitivity for HCC and also yields a comparable specificity. Thus, the combined use of CTAP and gadoxetic acid-enhanced MR imaging may improve the diagnostic performance for HCC.

Identification of diffusion weighted imaging would be affected before and after Gd-EOB-DTPA in patients with focal hepatic lesions: an observational study.

Background: Inserting diffusion weighted imaging (DWI) into the time interval between post contrast and hepatobiliary phase (HBP) is time saving and health economic friendly. However, whether DWI would be affected before and after Gd-EOB-DTPA is still unknown. This study aims to validate whether the DWI at both low and high b-values is affected before and after Gd-EOB-DTPA enhancement. Methods: From July 2019 to November 2019, seventy-three patients who satisfied the inclusion criteria were enrolled. Those patients were scanned with multiple b-value (b-value of 0, 50, 800, 1,000, and 1,200 s/mm2) DWI using a 3.0 T magnetic resonance (MR) scanner before and after the injection of Gd-EOB-DTPA. The final imaging diagnosis of the malignant liver lesions were made by histopathological analysis. The lesion-liver contrast intensity ratio (CIR) and the apparent diffusion coefficients (ADCs) of hepatic parenchyma and lesions at each b-value was evaluated. The Student's t-test or Mann-Whitney U test was used to compare the CIR and ADC between the MR images before and after contrast agent injection. In addition, the Student's t-test or Mann-Whitney U test was used to compare the ADC values between benign and malignant lesions. Receiver operating characteristics (ROC) curves were used to assess the area under the curve (AUC) of the ADC values in differentiating between benign and malignant lesions. Results: For the CIRs comparison, the CIRs showed no statistical significance before and after Gd-EOB-DTPA on b =0 (1.34±1.15 vs. 1.45±1.48, P=0.664), b=50 (1.23±1.13 vs. 1.35±1.34, P=0.982), b=800 (1.19±0.87 vs. 1.19±0.94, P=0.946), b=1,000 (1.21±0.90 vs. 1.32±1.05, P=0.294) and b=1,200 (1.25±1.03 vs. 1.45±1.48, P=0.165) s/mm2. For the ADC value comparison, the ADC also showed no statistical significance before and after Gd-EOB-DTPA on b=50 (4.04±2.82 vs. 3.91±3.00, P=0.151), b=800 (1.68±0.71 vs.1.67±0.76, P=0.163), b=1,000 (1.53±0.69 vs.1.50±0.70, P=0.078) and b=1,200 (1.48±0.66 vs. 1.48±0.70, P=0.294) s/mm2. Conclusions: DWI scanned between the interval of dynamic enhanced imaging and HBP imaging can save overall scanning time without influencing the CIRs, ADCs, and diagnostic capabilities of hepatic lesions at both low and high b-values.

New Liver MR Imaging Hallmarks for Small Hepatocellular Carcinoma Screening and Diagnosing in High-Risk Patients.

Objective: Early detection and diagnosis of hepatocellular carcinoma (HCC) is essential for prognosis; however, the imaging hallmarks for tumor detection and diagnosis has remained the same for years despite the use of many new immerging imaging methods. This study aimed to evaluate the detection performance of hepatic nodules in high risk patients using either hepatobiliary specific contrast (HBSC) agent or extracellular contrast agent (ECA), and further to compare the diagnostic performances for hepatocellular carcinoma (HCC) using different diagnostic criteria with the histopathological results as reference standard. Methods: This prospective study included 247 nodules in 222 patients (mean age, 53.32 ± 10.84 years; range, 22-79 years). The detection performance and imaging features of each nodule were evaluated in all MR sequences by three experienced abdominal radiologists. The detection performance of each nodule on all MR sequences were compared and further the diagnostic performance of various diagnostic criteria were evaluated. Results: For those patients who underwent ECA-MRI, the conventional imaging hallmark of "AP + PVP and/or DP" was recommended, as 60.19% diagnostic sensitivity, 80.95% specificity and 100% lesion detection rate. Additionally, for those patients who underwent HBSC-MRI, the diagnostic criteria of "DWI + HBP" was recommended. This diagnostic criteria demonstrated, both in all tumor size and for nodules ≤2 cm, higher sensitivity (93.07 and 90.16%, all p <0.05, respectively) and slightly lower specificity (64.71 and 87.50%, all p >0.05, respectively) than that of the European Association for the Study of the Liver (EASL) criteria. Conclusions: Different abbreviated MR protocols were recommended for patients using either ECA or HBSC. These provided imaging settings demonstrated high lesion detection rate and diagnostic performance for HCC.

Multiparametric Magnetic Resonance Imaging Improves the Prognostic Outcomes in Patients With Intrahepatic Cholangiocarcinoma After Curative-Intent Resection.

Purpose: The prognosis of patients with intrahepatic cholangiocarcinoma remains unclear. Thus, this study aimed at investigating whether additional multiparametric magnetic resonance imaging (mpMRI) would guide additional treatment and improve the prognostic outcomes of intrahepatic cholangiocarcinoma patients. Methods and Materials: This retrospective study included 256 patients undergoing dynamic enhanced computed tomography scan only (CT group) and 31 patients undergoing both mpMRI and computed tomography scans (CT+MR group). Propensity score matching (PSM) was used to minimize the potential selection bias and confounding effects. The overall survival (OS) and recurrence-free survival (RFS) rates were compared between the two groups. Results: More nodules (n = 6), additional biliary dilation (n = 4), and peritumoral parenchymal arterial phase hyperenhancement (n = 18) were found with the additional mpMRI scan, which led to treatment modification. Cox regression analysis revealed the survival advantage of additional mpMRI imaging based on the OS (HR 0.396, 95% CI 0.239-0.657, p < 0.001; PSM HR 0.400, 95% CI 0.218-0.736, p = 0.003) and RFS (HR 0.558, 95% CI 0.352-0.882, p = 0.013; PSM HR 0.508, 95% CI 0.288-0.897, p = 0.020). Conclusions: Additional mpMRI helps clinicians to select better treatment options, lower the risk of tumor recurrence, and improve the overall survival.

Prediction of Remnant Liver Regeneration after Right Hepatectomy in Patients with Hepatocellular Carcinoma Using Preoperative CT Texture Analysis and Clinical Features.

Objectives: To predict the regenerative rate of liver in patients with HCCs after right hepatectomy using texture analysis on preoperative CT combined with clinical features. Materials and Methods: 88 patients with 90 HCCs who underwent right hepatectomy were retrospectively included. The future remnant liver was semiautomatically segmented, and the volume of future remnant liver on preoperative CT (LVpre) and the volume of remnant liver on following-up CT (LVfu) were measured. We calculated the regeneration index (RI) by the following equation: (LVfu - LVpre)/LVpre) × 100 (%). The support vector machine recursive method was used for the feature selection. The Naive Bayes classifier was used to predict liver RI, and 5-fold cross-validation was performed to adjust the parameters. Sensitivity, specificity, and accuracy were calculated to evaluate the diagnostic efficiency of the model. Results: The mean RI was 142.99 ± 92.17%. Of all clinical parameters and texture features, the AST, ALB, PT-INR, Perc.10%, and S(5, -5)Correlat were found to be statistically significant with RI. The diagnostic sensitivity, specificity, and accuracy of the model in the training group were 0.902, 0.634, and 0.768, and the AUC value of the obtained model was 0.841. In the test group, the sensitivity, specificity, and accuracy of the model were 1.0, 0.429, and 0.778, respectively, and the AUC value was 0.844. Conclusion: The use of texture analysis on preoperative CT combined with clinical features can be helpful in predicting the liver regeneration rate in patients with HCCs after right hepatectomy.

Itraconazole Oral Solution for a Case of Infantile Hemangioma: Monitoring the Efficacy by Dermoscopy and MRI.

Infantile hemangioma is a common and challenging benign vascular tumor. Although involution is spontaneous, approximately 10% of infantile hemangioma of large size or in specific locations may cause ulceration, severe cosmetic and functional problems that may require intervention. Treatment options include oral propranolol, topical timolol, and oral corticosteroids. However, the clinical response is not always satisfactory. We report the case of a 4-month-old boy who presented with an irregular erythematous plaque on his left shoulder 3 days after birth. Infantile hemangioma was diagnosed. Topical application of 0.5 ml of 0.5% timolol maleate eye drops for half an hour each time three times a day was initiated. After nearly 3 months of follow-up, the size of the lesion gradually increased. Finally, after 115 days of treatment with itraconazole oral solution (the total dose was about 4025 mg), the refractory infantile hemangioma was successfully treated. Hepatic and renal function remained normal with only mild diarrhea during the course of oral medication. Treatment compliance of oral itraconazole in infants has been reported to be good. Dermoscopy and magnetic resonance imaging (MRI) played a crucial role in in vivo observation of the hemangioma changes with vascular regression during the treatment process.

MRI of Temporomandibular Joint Disorders: Recent Advances and Future Directions.

Temporomandibular joint disorders (TMDs) are a prevalent disease covering pain and dysfunction of temporomandibular joints and masticatory muscles, which can be detrimental to quality of life. Magnetic resonance imaging (MRI) is a powerful and noninvasive tool for the imaging and understanding of TMD. With the recent technical development of dynamic and quantitative MRI techniques, including diffusion-weighted imaging, T2 mapping, and ultrashort/zero echo time, it is now feasible in TMD imaging and has been preliminarily investigated with promising results. In this review we will discuss the recent advances of MRI techniques in TMD and its future directions, and hope to highlight the scientific potential and clinical value of novel MRI techniques in diagnosing and treating TMD. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 3.

A New Diagnostic Criterion with Gadoxetic Acid-Enhanced MRI May Improve the Diagnostic Performance for Hepatocellular Carcinoma.

BACKGROUND: To prospectively establish and validate new diagnostic criterion (DC) for liver-specific contrast agents and further compared the diagnostic sensitivity and specificity with conventional DC. METHODS: Institutional Review Board approved and written informed consent were obtained for this prospective study. Two board-certified reviewers established the reference standard as hepatocellular carcinoma (HCC), non-HCC lesions by using marks on all cross-sectional MR images. Another 2 abdominal radiologists independently performed the marked lesion observations using 5 different DCs, including DC-1: arterial phase hyperenhancement (APHE) and portal venous phase washout; DC-2: APHE and hepatobiliary phase (HBP) hypointensity; DC-3: APHE and diffusion-weighted imaging (DWI) hyperintensity; DC-4: HBP hypointensity and DWI hyperintensity; DC-5: HBP hypointensity, DWI hyperintensity and excluded these markedly T2 hyperintensity. Diagnostic performance of sensitivity, specificity, and accuracy for each imaging DC was calculated, per-lesion diagnostic sensitivity and specificity of imaging criteria were compared by using McNemars test. RESULTS: A total of 215 patients were included (mean age 53.82 ± 11.24 years; range 24-82 years) with 265 hepatic nodules (175 HCCs and 90 non-HCCs). The DC-4 (93.71%; 164/175) and DC-5 (92.57%; 162/175) yielded the highest diagnostic sensitivity and was better than DC-1 (72.57%; 127/175), DC-2 (82.86%; 145/175), and DC-3 (82.29%; 144/175) (all p < 0.001). The specificity of DC-1 (94.44%; 85/90) was significantly higher than that with DC-2 (83.33%; 75/90), DC-3 (84.44%; 76/90), DC-4 (74.44%; 67/90), and DC-5 (82.22%; 74/90) (all p < 0.05). Additionally, the DC-4 and DC-5 achieved the highest area under curve value of 0.841 (95% CI 0.783-0.899) and 0.874 (95% CI 0.822-0.925). CONCLUSIONS: The combined use of HBP hypointensity and DWI hyperintensity as a new DC for HCC enables a high diagnostic sensitivity and comparable specificity.

Improved Display of Hepatic Arterial Anatomy Using Differential Subsampling With Cartesian Ordering (DISCO) With Gadoxetic Acid-Enhanced MRI: Comparison With Single Arterial Phase MRI and Computed Tomographic Angiography.

BACKGROUND: In clinical practice arterial anatomy evaluation is often determined using computed tomographic angiography (CTA); the effect of enhanced MRI has been neglected. PURPOSE: To evaluate whether multiple arterial phase (MAP) images from patients who underwent differential subsampling with Cartesian ordering (DISCO) acquisition would improve the hepatic arterial display compared with single arterial phase (SAP) and CTA. STUDY TYPE: A prospective, randomized trial. SUBJECTS: In all, 130 patients (mean age, 55.81 ± 9.43 years; range, 35-78 years) including 89 men and 41 women. FIELD STRENGTH/SEQUENCE: 3.0T, DISCO, liver acquisition with volume acceleration-flexible (LAVA-Flex), CTA. ASSESSMENT: A simple randomization was conducted and the study was subdivided into study part I (DISCO vs. SAP) and study part II (DISCO vs. CTA). Ten hepatic arterial segments were independently evaluated by three readers in the axial plane and the quality of hepatic arterial display was assessed using a four-point scale. STATISTICAL TESTS: Kendall's W-test, χ2 test, Mann-Whitney U-test, and Kruskal-Wallis one-way analysis of variance (ANOVA) test. RESULTS: Excellent interobserver agreement was obtained for hepatic arterial display (all Kendall's W values >0.80). For study part I, the mean arterial display scores for the common hepatic artery (CHA), proper hepatic artery (PHA), left hepatic artery (LHA), right hepatic artery (RHA), left gastric artery (LGA), and gastroduodenal artery (GDA) obtained with DISCO were higher than that obtained with SAP imaging (all P < 0.01). For study part II, comparable image quality for CHA (P = 0.798), PHA (P = 0.440), LHA (P = 0.211), RHA (P = 0.775) LGA (P = 0.468), and GDA (P = 0.801) was obtained with DISCO and CTA. DATA CONCLUSION: The use of MAP acquisition with DISCO is superior to the use of SAP in hepatic arterial display and compares favorably with CTA; in the future, DISCO possibly can replace the latter ionization-related method to provide a more comprehensive evaluation of the liver arterial vessels. LEVEL OF EVIDENCE: 1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1766-1776.

IVIM improves preoperative assessment of microvascular invasion in HCC.

PURPOSE: To prospectively evaluate the potential role of intravoxel incoherent motion (IVIM) and conventional radiologic features for preoperative prediction of microvascular invasion (MVI) in patients with hepatocellular carcinoma (HCC). METHODS: Institutional review board approval and written informed consent were obtained for this study. A cohort comprising 115 patients with 135 newly diagnosed HCCs between January 2016 and April 2017 were evaluated. Two radiologists independently reviewed the radiologic features and the apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudodiffusion coefficient (D*), and pseudodiffusion component fraction (f) were also measured. Interobserver agreement was checked and univariate and multivariate logistic regressions were used for screening the risk factors. Receiver operating characteristics (ROC) curve analyses were performed to evaluate the diagnostic performance. RESULTS: Features significantly related to MVI of HCC at univariate analysis were reduced ADC (odds ratio, 0.341; 95% CI, 0.211-0.552; p < 0.001), D (odds ratio, 0.141; 95% CI, 0.067-0.299; p < 0.001), and irregular circumferential enhancement (odds ratio, 9.908; 95% CI, 3.776-25.996; p < 0.001). At multivariate analysis, only D value (odds ratio, 0.096; 95% CI, 0.025-0.364; p < 0.001) was the independent risk factor for MVI of HCC. The mean D value for MVI of HCC showed an area under ROC curves of 0.815 (95% CI, 0.740-0.877). CONCLUSION: IVIM model-derived D value is superior to ADC measured with mono-exponential model for evaluating the MVI of HCC. Among MR imaging features, tumor margin, enhancement pattern, tumor capsule, and peritumoral enhancement were not predictive for MVI. KEY POINTS: • Diffusion MRI is useful for non-invasively evaluating the microvascular invasion of hepatocellular carcinoma. • IVIM model is advantageous over mono-exponential model for assessing the microvascular invasion of hepatocellular carcinoma. • Decreased D value was the independent risk factor for predicting MVI of HCC.

Accelerated Time-of-Flight Magnetic Resonance Angiography with Sparse Undersampling and Iterative Reconstruction for the Evaluation of Intracranial Arteries.

OBJECTIVE: To compare the image quality of three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA) with sparse undersampling and iterative reconstruction (sparse TOF) with that of conventional TOF MRA. MATERIALS AND METHODS: This study included 56 patients who had undergone sparse TOF MRA for intracranial artery evaluation on a 3T MR scanner. Conventional TOF MRA scans were also acquired from 29 patients with matched acquisition times and another 27 patients with matched scanning parameters. The image quality was scored using a five-point scale based on the delineation of arterial vessel segments, artifacts, overall vessel visualization, and overall image quality by two radiologists independently, and the data were analyzed using the non-parametric Wilcoxon signed-rank test. Contrast ratios (CRs) of vessels were compared using the paired t test. Interobserver agreement was calculated using the kappa test. RESULTS: Compared with conventional TOF at the same spatial resolution, sparse TOF with an acceleration factor of 3.5 could reduce acquisition time by 40% and showed comparable image quality. In addition, when compared with conventional TOF with the same acquisition time, sparse TOF with an acceleration factor of 5 could also achieve higher spatial resolution, better delineation of vessel segments, fewer artifacts, higher image quality, and a higher CR (p < 0.05). Good-to-excellent interobserver agreement (κ: 0.65-1.00) was obtained between the two radiologists. CONCLUSION: Compared with conventional TOF, sparse TOF can achieve equivalent image quality in a reduced duration. Furthermore, using the same acquisition time, sparse TOF could improve the delineation of vessels and decrease image artifacts.

Esophageal carcinoma: Intravoxel incoherent motion diffusion-weighted MRI parameters and histopathological correlations.

BACKGROUND: The pathological grade of esophageal carcinoma is highly determinant of patient prognosis, but it still cannot be adequately evaluated preoperatively. Compared with conventional diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM) diffusion-weighted MRI can separate true molecular diffusion and perfusion in tissues and has been shown to be useful in characterizing malignant tumors. There is no report that compared IVIM and conventional DWI in grading esophageal carcinoma. PURPOSE: To prospectively determine the diagnostic performance of conventional DWI and IVIM models in differentiating the pathological differentiated grade of esophageal carcinoma. STUDY TYPE: Prospective. POPULATION: A cohort comprising 81 patients with newly diagnosed esophageal squamous cell carcinoma (ESCC) between December 2015 and August 2017 were evaluated. FIELD STRENGTH/SEQUENCE: 3.0T, axial echo-planer imaging, fast spin echo (FSE) sequence, IVIM sequence (b = 0, 20, 50, 80, 100, 150, 200, 400, 600, 800, 1000, 1200). ASSESSMENT: Apparent diffusion coefficient (ADC), true ADC (ADCslow ), pseudo ADC (ADCfast ), and perfusion fraction (f) of each tumor were calculated by two independent radiologists. Histopathologic grade was used as the reference standard. STATISTICAL TESTS: Games-Howell test; diagnostic accuracy; Spearman correlation; intraclass correlation coefficient; and Bland-Altman analysis. Receiver operating characteristics (ROC) curves. RESULTS: ADCslow demonstrated the highest area under curve (AUC) with a value of 0.830 (95% confidence interval [CI]: 0.730-0.904) and 0.816 (95% CI: 0.714-0.893) by two radiologists, followed by ADC with a value of 0.754 (95% CI: 0.646-0.843) and 0.761 (95% CI: 0.653-0.848). Good correlation was obtained between the histologic grade and ADCslow (r(R1) = 0.748, r(R2) = 0.720) and ADC (r(R1) = 0.576, r(R2) = 0.571). DATA CONCLUSION: ADCslow and ADC had a significantly higher performance than the ADCfast and f, and ADCslow had a significantly higher performance than the ADC. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:253-261.

Intravoxel incoherent motion diffusion-weighted imaging for assessment of histologic grade of hepatocellular carcinoma: comparison of three methods for positioning region of interest.

OBJECTIVES: To prospectively compare the diagnostic performances of three methods of region of interest (ROI) placement for the measurements of intravoxel incoherent motion (IVIM) diffusion-weighted MR imaging in differentiating the histologic grade of hepatocellular carcinoma (HCC). METHODS: Eighty-seven patients with 91 newly diagnosed HCCs were studied using IVIM imaging. Two attending radiologists separately identified the selection of tumour tissue for ROI positioning. Three different ROI positioning methods, namely the whole tumour volume (WTV) method, three-ROI method and one-section method, were used for the measurement. Kruskal-Wallis rank test or one-way ANOVA was used to compare the difference in IVIM parameters and ADC across the three different ROI positioning methods. Spearman correlation analysis was used to determine the correlation between each parameter and Edmondson-Steiner (E-S) grade. Receiver operating characteristics (ROC) curve analyses were performed to evaluate the diagnostic performance. RESULTS: For the ADC and ADCslow, the mean value measured by using the WTV method was significant higher than the one-section and three-ROI methods (all p < 0.01). For the ADCslow, the highest area under curve (AUC) with a value of 0.969 was obtained by using the WTV method, followed by the one-section method (AUC = 0.938) and three-ROI method (AUC = 0.873). Additionally, for the ADC, AUC values were 0.861 for WTV method, 0.840 for one-section method and 0.806 for three-ROI method. CONCLUSIONS: Different ROI positioning methods used significantly affect the IVIM parameters and ADC measurements. Measurements of ADCslow value derived from WTV method entailed the highest diagnostic performance in grading HCC. KEY POINTS: • Diffusion MRI is useful for non-invasively differentiating the histologic grade of hepatocellular carcinoma. • Different ROI positioning methods used significantly affect the IVIM parameters and ADC measurements. • IVIM model is advantageous over mono-exponential model for assessing the histologic grade of hepatocellular carcinoma.