Distinguishing Cardiac Amyloidosis and Hypertrophic Cardiomyopathy by Thickness and Myocardial Deformation of the Right Ventricle.

OBJECTIVES: To compare right ventricular thickness (RVT) and deformation of cardiac amyloidosis (CA) and hypertrophic cardiomyopathy (HCM) patients. METHODS: Sixty CA (mean age 58 ± 10 years; 33 males (55%)) and sixty HCM patients (mean age 55 ± 14 years; 27 males (45%)) were retrospectively enrolled. RVT, global radical peak strain (GRPS), global longitudinal peak strain (GLPS), and global circumferential peak stain (GCPS) were analyzed. To determine the cutoff values of the RVT and RV strain parameters for distinguishing CA from HCM, the areas under the receiver operating characteristic curve (AUCs) were analyzed. RESULTS: RVT of CA patients was significantly thicker than that of HCM patients (7.8 ± 2.1 vs 5.9 ± 1.3, p < 0.001). Moreover, significantly decreased RV-GRPS (12.1 ± 6.9 vs 23.5 ± 12.1, p < 0.001), RV-GCPS (-3.4 ± 2.2 vs -5.6 ± 3.5, p < 0.001), and RV-GLPS (-4.6 ± 2.3 vs -11.1 ± 4.9, p < 0.001) were observed in CA patients compared with HCM patients. RVT and RV strain demonstrate comparable diagnostic accuracy in differentiating CA from HCM. In particular, RV-GLPS combined with RVT showed the best performance for discriminating CA from HCM (AUC = 0.92, 95% CI: 0.85 to 0.96, p = 0.0001). CONCLUSIONS: Right ventricular myocardial thickness and deformation of CA patients was more severe than HCM patients. RV-GLPS combined with RVT presents an excellent diagnostic performance in distinguishing CA and HCM.

[Application of Automated Machine Learning Based on Radiomics Features of T2WI and RS-EPI DWI to Predict Preoperative T Staging of Rectal Cancer].

OBJECTIVE: To explore the radiomics features of T2 weighted image (T2WI) and readout-segmented echo-planar imaging (RS-EPI) plus difusion-weighted imaging (DWI), to develop an automated mahchine-learning model based on the said radiomics features, and to test the value of this model in predicting preoperative T staging of rectal cancer. METHODS: The study retrospectively reviewed 131 patients who were diagnosed with rectal cancer confirmed by the pathology results of their surgical specimens at West China Hospital of Sichuan University between October, 2017 and December, 2018. In addition, these patients had preoperative rectal MRI. Tumor regions from preoperative MRI were manually segmented by radiologists with the ITK-SNAP software from T2WI and RS-EPI DWI images. PyRadiomics was used to extract 200 features-100 from T2WI and 100 from the apparent diffusion coefficient (ADC) calculated from the RS-EPI DWI. MWMOTE and NEATER were used to resample and balance the dataset, and 13 cases of T 1-2 stage simulation cases were added. The overall dataset was divided into a training set (111 cases) and a test set (37 cases) by a ratio of 3∶1. Tree-based Pipeline Optimization Tool (TPOT) was applied on the training set to optimize model parameters and to select the most important radiomics features for modeling. Five independent T stage models were developed accordingly. Accuracy and the area under the curve ( AUC) of receiver operating characteristic (ROC) were used to pick out the optimal model, which was then applied on the training set and the original dataset to predict the T stage of rectal cancer. RESULTS: The performance of the the five T staging models recommended by automated machine learning were as follows: The accuracy for the training set ranged from 0.802 to 0.838, sensitivity, from 0.762 to 0.825, specificity, from 0.833 to 0.896, AUC, from 0.841 to 0.893, and average precision (AP) from 0.870 to 0.901. After comparison, an optimal model was picked out, with sensitivity, specificity and AUC for the training set reaching 0.810, 0.875, and 0.893, respectively. The sensitivity, specificity and AUC for the test set were 0.810, 0.813, and 0.810, respectively. The sensitivity, specificity and AUC for the original dataset were 0.810, 0.830, and 0.860, respectively. CONCLUSION: Based on the radiomics data of T2WI and RS-EPI DWI, the model established by automated machine learning showed a fairly high accuracy in predicting rectal cancer T stage.

[Application of MRI-based Radiomics Models in the Assessment of Hepatic Metastasis of Rectal Cancer].

OBEJECTIVE: To explore the clinical value of using radiomics models based on different MRI sequences in the assessment of hepatic metastasis of rectal cancer. METHODS: 140 patients with pathologically confirm edrectal cancer were included in the study. They underwent baseline magnetic resonance imaging (MRI) between April 2015 and May 2018 before receiving any treatment. According to the results of liver biopsy, surgical pathology, and imaging, patients were put into two groups, the patients with hepatic metastasis and those without. T2 weighted images (T2WI), diffusion weighted images (DWI) and apparent diffusion coefficient (ADC) images were used to draw the region of interest (ROI) of primary lesions on consecutive slices on ITK-SNAP. 3-D ROIs were generated and loaded into Artificial Intelligent Kit for extraction of radiomics features and 396 features were extracted for each sequence. The feature data were preprocessed on Python and the samples were oversampled, using Support Vector Machine-Synthetic Minority Over-Sampling Technique (SVM-SMOTE) to balance the number of samples in the group with liver metastasis and the group with no liver metastasis at the end of the follow-up. Then, the samples were divided into the training cohort and the test cohort at a ratio of 2∶1. The logistic regression models were developed with selected radionomic features on R software. The receiver operating characteristics (ROC) curves and calibration curves were used to evaluate the performance of the models. RESULTS: In total, 52 patients with liver metastasis and 88 patients without liver metastasis at the end of follow-up were enrolled. Carcinoembryonic antigen (CEA) and T stage and N stage evaluated on the MRI images showed statistically significant difference between the two groups ( P<0.05). After data preprocessing and selecting, except for 17 non-radiomic features, the model combining T2WI, DWI and ADC features, the model of T2WI features alone, the model of DWI features alone and the model of ADC features alone were developed with 32 features, 10 features, 30 features and 15 features, respectively. The combined model (T2WI+DWI+ADC), the T2WI model, and the ADC model can assess hepatic metastasis accurately, with the area under curve ( AUC) on the train set reaching 93.5%, 89.2%, 90.6% and that of the test set reaching 80.8%, 80.5%, 81.4%, respectively. The combined model did not show a higher AUC than those of the T2WI and ADC alone models. Model based on DWI features has a slightly insufficient AUC of 90.3% in the train set and 75.1% in the test set. The calibration curve showed the smallest fluctuation in the combined model, which is closest fit to the diagonal reference line. The fluctuation in the three independent data set models were similar. The calibration curves of all the four models showed that as the risk increased, the prediction of the models turned from an underestimation to an overestimating the risk. In brief, the combined model showed the best performance, with the best fit to the diagonal reference line in calibration curve and high AUC comparable to the AUC of the T2WI model and ADC model. The performance of T2WI and ADC alone models were second to that of the combined model, while the DWI alone model showed relatively poor performance. CONCLUSION: Radiomics models based on MRI could be effectively used in assessing liver metastasis in rectal cancer, which may help determine clinical staging and treatment.

Noninvasive oxygenation assessment after acute myocardial infarction with breathing maneuvers-induced oxygenation-sensitive magnetic resonance imaging.

The safety profiles when performing stress oxygenation-sensitive magnetic resonance imaging (OS-MRI) have raised concerns in clinical practice. Adenosine infusion can cause side effects such as chest pain, dyspnea, arrhythmia, and even cardiac death. The aim of this study was to investigate the feasibility of breathing maneuvers-induced OS-MRI in acute myocardial infarction (MI). This was a prospective study, which included 14 healthy rabbits and nine MI rabbit models. This study used 3 T MRI/modified Look-Locker inversion recovery sequence for native T1 mapping, balanced steady-state free precession sequence for OS imaging, and phase-sensitive inversion recovery sequence for late gadolinium enhancement. The changes in myocardial oxygenation (ΔSI) were assessed under two breathing maneuvers protocols in healthy rabbits: a series of extended breath-holding (BH), and a combined maneuver of hyperventilation followed by the extended BH (HVBH). Subsequently, OS-MRI with HVBH in acute MI rabbits was performed, and the ΔSI was compared with that of adenosine stress protocol. Student's t-test, Wilcoxon rank test, and Friedman test were used to compare ΔSI in different subgroups. Pearson and Spearman correlation was used to obtain the association of ΔSI between breathing maneuvers and adenosine stress. Bland-Altman analysis was used to assess the bias of ΔSI between HVBH and adenosine stress. In healthy rabbits, BH maneuvers from 30 to 50 s induced significant increase in SI compared with the baseline (all p < 0.05). By contrast, hyperventilation for 60 s followed by 10 s-BH (HVBH 10 s) exhibited a comparable ΔSI to that of stress test (p = 0.07). In acute MI rabbits, HVBH 10 s-induced ΔSIs among infarcted, salvaged, and the remote myocardial area were no less effectiveness than adenosine stress when performing OS-MRI (r = 0.84; p < 0.05). Combined breathing maneuvers with OS-MRI have the potential to be used as a nonpharmacological alternative for assessing myocardial oxygenation in patients with acute MI. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2.

Multi-modal radiomics model to predict treatment response to neoadjuvant chemotherapy for locally advanced rectal cancer.

BACKGROUND: Neoadjuvant chemotherapy is currently recommended as preoperative treatment for locally advanced rectal cancer (LARC); however, evaluation of treatment response to neoadjuvant chemotherapy is still challenging. AIM: To create a multi-modal radiomics model to assess therapeutic response after neoadjuvant chemotherapy for LARC. METHODS: This retrospective study consecutively included 118 patients with LARC who underwent both computed tomography (CT) and magnetic resonance imaging (MRI) before neoadjuvant chemotherapy between October 2016 and June 2019. Histopathological findings were used as the reference standard for pathological response. Patients were randomly divided into a training set (n = 70) and a validation set (n = 48). The performance of different models based on CT and MRI, including apparent diffusion coefficient (ADC), dynamic contrast enhanced T1 images (DCE-T1), high resolution T2-weighted imaging (HR-T2WI), and imaging features, was assessed by using the receiver operating characteristic curve analysis. This was demonstrated as area under the curve (AUC) and accuracy (ACC). Calibration plots with Hosmer-Lemeshow tests were used to investigate the agreement and performance characteristics of the nomogram. RESULTS: Eighty out of 118 patients (68%) achieved a pathological response. For an individual radiomics model, HR-T2WI performed better (AUC = 0.859, ACC = 0.896) than CT (AUC = 0.766, ACC = 0.792), DCE-T1 (AUC = 0.812, ACC = 0.854), and ADC (AUC = 0.828, ACC = 0.833) in the validation set. The imaging performance for extramural venous invasion detection was relatively low in both the training (AUC = 0.73, ACC = 0.714) and validation (AUC = 0.578, ACC = 0.583) sets. The multi-modal radiomics model reached an AUC of 0.925 and ACC of 0.886 in the training set, and an AUC of 0.93 and ACC of 0.875 in the validation set. For the clinical radiomics nomogram, good agreement was found between the nomogram prediction and actual observation. CONCLUSION: A multi-modal nomogram using traditional imaging features and radiomics of preoperative CT and MRI adds accuracy to the prediction of treatment outcome, and thus contributes to the personalized selection of neoadjuvant chemotherapy for LARC.

The prognostic value of right ventricular deformation derived from cardiac magnetic resonance tissue tracking for all-cause mortality in light-chain amyloidosis patients.

BACKGROUND: Early detection of right ventricular (RV) dysfunction is vital for determining the prognosis of light-chain amyloidosis (AL) patients. While few studies focused on RV deformation due to the limitation of research methods. The aim of this study was to determine the prognostic significance of RV myocardial strain in AL patients assessed by cardiac magnetic resonance (CMR) tissue tracking. METHODS: Sixty-four AL patients (28 females and 36 males, mean age 58±12.8 years old; range 25-81 years old) were enrolled from 1 October 2014 through 31 March 2017 and compared with 20 age- and sex-matched controls. Fifty-one AL patients met the criteria for cardiac amyloidosis (CA). Deformation parameters of both RV and left ventricle (LV) were measured by the CMR tissue tracking technique including myocardial global radial peak strain (GRPS), global circumferential peak strain (GCPS), and global longitudinal peak strain (GLPS). The follow-up time was 20 months or until the occurrence of death. RESULTS: Thirty-two (50%) had preserved RV ejection fraction (RVEF ≥45%). AL patients had significantly lower RV-GRPS (20.3±2.12 vs. 31.31±7.61), GCPS (-2.12±0.88 vs. -13.71±2.53), and GLPS (-5.33±0.64 vs. -14.239±2.99) than controls even RVEF remain preserved (all P<0.001). Compared with controls and patients without CA, RV-GRPS (12.26±1.26 vs. 29.72±3.54, P<0.001) and RV-GLPS (-3.78±2.25 vs. -5.66±2.08, P<0.05) were significantly lower in patients with CA. Cox multivariate analyses demonstrated that RV-GRPS [hazard ratio (HR) =0.93, 95% CI: 0.88-0.98, P=0.007] and Mayo stage were (HR =3.11, 95% CI: 1.30-7.41, P=0.01) predictors of mortality in AL patients. CONCLUSIONS: CMR tissue tracking is a feasible and highly reproducible technique for the analysis of RV deformation and could aid in the early diagnosis of RV involvement in AL patients. RV-GRPS of RV strain and Mayo stage provides prognostic information about mortality in AL patients.

[The Application Value of One-stop CT Myocardial Perfusion Imaging in the Evaluation of Patients with Severe Coronary Artery Stenosis].

ObstractPurpose "One-stop" CT myocardial perfusion imaging (CT-MPI) was compared with cardiac magnetic resonance(CMR) to investigate its application value in evaluating patients with severe coronary artery stenosis.MethodsFifty patients with coronary artery stenosis≥90% of at least one major coronary arteries comfirmed by coronary angiography (CAG) in the department of cardiology in our hospital, who referred for coronary artery stent implantation were prospectively enrolled. All the patients underwent "One-stop" CT-MPI within a week before surgery, among which 22 patients underwent CMR examination simultaneously. The postprocessing software Ziostation2 was used to obatin and compare the perfusion parameters of patients with normal and perfusion defect myocardium, including blood flow (BF), blood volume (BV), peak time (TTP), and mean transit time (MTT). Pearson correlation analysis was used to compare the correlation of relative perfusion parameters (defect/normal myocardium) between CT and CMR. Bland-Altman analysis was used to analyze the consistency between CT and CMR in left ventricular (LV) function parameters measurements.ResultsCompared with normal myocardium, BV and BF of perfusion defect myocardium were significantly decreased, while MTT and TTP were significantly prolonged (all P < 0.05). The rBV, rBF, rMTT and rTTP were medium to high positive correlated between CT and CMR (r=0.685, 0.641, 0.871, 0.733, respectively, all P < 0.05). Bland-Altman analysis showed that 95% (21/22) points were within the 95% limits of agreement (LoA), suggesting the LV function parameters measurements between two methods were highly consistent.Conclusion"One-stop" CT-MPI can simultaneously obtain the information about coronary anatomy, myocardial perfusion and LV function. It is of great value in the evaluation of patients with severe coronary artery stenosis, with shorter scan time and less contraindications compared with CMR.

Accurate identification of myocardial viability after myocardial infarction with novel manganese chelate-based MR imaging.

We developed a novel manganese (Mn2+ ) chelate for magnetic resonance imaging (MRI) assessment of myocardial viability in acute and chronic myocardial infarct (MI) models, and compared it with Gadolinium-based delay enhancement MRI (Gd3+ -DEMRI) and histology. MI was induced in 14 rabbits by permanent occlusion of the left circumflex coronary artery. Gd3+ -DEMRI and Mn2+ chelate-based delayed enhancement MRI (Mn2+ chelate-DEMRI) were performed at 7 days (acute MI, n = 8) or 8 weeks (chronic MI, n = 6) after surgery with sequential injection of 0.15 mmol/kg Gd3+ and Mn2+ chelate. The biodistribution of Mn2+ in tissues and blood was measured at 1.5 and 24 h. Blood pressure, heart rate (HR), left ventricular (LV) function, and infarct fraction (IF) were analyzed, and IF was compared with the histology. The Mn2+ chelate group maintained a stable hemodynamic status during experiment. For acute and chronic MI, all rabbits survived without significant differences in HR or LV function before and after injection of Mn2+ chelate or Gd3+ (p > 0.05). Mn2+ chelate mainly accumulated in the kidney, liver, spleen, and heart at 1.5 h, with low tissue uptake and urine residue at 24 h after injection. In the acute MI group, there was no significant difference in IF between Mn2+ chelate-DEMRI and histology (22.92 ± 2.21% vs. 21.79 ± 2.25%, respectively, p = 0.87), while Gd3+ -DEMRI overestimated IF, as compared with histology (24.54 ± 1.73%, p = 0.04). In the chronic MI group, there was no significant difference in IF between the Mn2+ chelate-DEMRI, Gd3+ -DEMRI, and histology (29.50 ± 11.39%, 29.95 ± 9.40%, and 29.00 ± 10.44%, respectively, p > 0.05), and all three were well correlated (r = 0.92-0.96, p < 0.01). We conclude that the use of Mn2+ chelate-DEMRI is reliable for MI visualization and identifies acute MI more accurately than Gd3+ -DEMRI.

Hepatocellular carcinoma: Can LI-RADS v2017 with gadoxetic-acid enhancement magnetic resonance and diffusion-weighted imaging improve diagnostic accuracy?

BACKGROUND: The Liver Imaging Reporting and Data System (LI-RADS), supported by the American College of Radiology (ACR), has been developed for standardizing the acquisition, interpretation, reporting, and data collection of liver imaging examinations in patients at risk for hepatocellular carcinoma (HCC). Diffusion-weighted imaging (DWI), which is described as an ancillary imaging feature of LI-RADS, can improve the diagnostic efficiency of LI-RADS v2017 with gadoxetic acid-enhanced magnetic resonance imaging (MRI) for HCC. AIM: To determine whether the use of DWI can improve the diagnostic efficiency of LI-RADS v2017 with gadoxetic acid-enhanced magnetic resonance MRI for HCC. METHODS: In this institutional review board-approved study, 245 observations of high risk of HCC were retrospectively acquired from 203 patients who underwent gadoxetic acid-enhanced MRI from October 2013 to April 2018. Two readers independently measured the maximum diameter and recorded the presence of each lesion and assigned scores according to LI-RADS v2017. The test was used to determine the agreement between the two readers with or without DWI. In addition, the sensitivity (SE), specificity (SP), accuracy (AC), positive predictive value (PPV), and negative predictive value (NPV) of LI-RADS were calculated. Youden index values were used to compare the diagnostic performance of LI-RADS with or without DWI. RESULTS: Almost perfect interobserver agreement was obtained for the categorization of observations with LI-RADS (kappa value: 0.813 without DWI and 0.882 with DWI). For LR-5, the diagnostic SE, SP, and AC values were 61.2%, 92.5%, and 71.4%, respectively, with or without DWI; for LR-4/5, they were 73.9%, 80%, and 75.9% without DWI and 87.9%, 80%, and 85.3% with DWI; for LR-4/5/M, they were 75.8%, 58.8%, and 70.2% without DWI and 87.9%, 58.8%, and 78.4% with DWI; for LR- 4/5/TIV, they were 75.8%, 75%, and 75.5% without DWI and 89.7%, 75%, and 84.9% with DWI. The Youden index values of the LI-RADS classification without or with DWI were as follows: LR-4/5: 0.539 vs 0.679; LR-4/5/M: 0.346 vs 0.467; and LR-4/5/TIV: 0.508 vs 0.647. CONCLUSION: LI-RADS v2017 has been successfully applied with gadoxetate-enhanced MRI for patients at high risk for HCC. The addition of DWI significantly increases the diagnostic efficiency for HCC.

Evaluation of Decellularized Bovine Tendon Sheets for Achilles Tendon Defect Reconstruction in a Rabbit Model.

BACKGROUND: Achilles tendon (AT) defects frequently occur in trauma and chronic injuries. Currently, no method can satisfactorily reconstruct the AT with completely restored function. PURPOSE: To evaluate the postoperative outcomes of AT defect reconstruction with decellularized bovine tendon sheets (DBTSs) in a rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: DBTSs were prepared from bovine tendons after compression, decellularization, antigen extraction, freeze drying, and sterilization. Platelet-rich plasma (PRP) was obtained by differential centrifugation. Sixty-three rabbits were used in this study, and the AT defect model was created bilaterally. All rabbits were divided into 3 groups (n = 21). In the DBTS group and the DBTS + PRP group, 2-cm-long AT was excised and reconstructed by DBTSs or PRP-treated DBTSs. In the control group, the rabbits underwent AT transection, and stumps were sutured. After surgery, all rabbits were assessed by ultrasonography and magnetic resonance imaging and then sacrificed for histological examination and biomechanical testing at 4, 8, or 12 weeks. RESULTS: Gross observations demonstrated the absence of immunologic incompatibility and rejection. Histological examination showed that DBTSs promoted host cell infiltration and new fibrous tissue integration as compared with the control group. In each group, there was an AT-like structure formation and aligned collagen fiber deposition at 12 weeks. Mechanical properties of the reconstructed AT were not significantly different among the 3 groups at 4, 8, and 12 weeks after surgery ( P > .05). Ultrasonography and magnetic resonance imaging results illustrated that the reconstructed AT from each group maintained remodeling, and there was no significant difference in the echogenicity scoring ( P > .05) and percentages of good and excellent ( P > .05) among the 3 groups. CONCLUSION: DBTSs, which retain the native tendon structure and bioactive factors, had the ability to remodel and integrate into the rabbit AT and improve the healing process. CLINICAL RELEVANCE: DBTSs could serve as an effective bioscaffold to reconstruct AT defects.

Readout-segmented echo-planar diffusion-weighted MR for the evaluation of aggressive characteristics of rectal cancer.

To evaluate whether aggressive characteristics of rectal cancer can be predicted by the apparent diffusion coefficient (ADC) obtained using readout-segmented echo-planar imaging (rs-EPI) diffusion-weighted magnetic resonance. We enrolled one hundred and fifteen patients. The image quality of ADC maps by rs-EPI was compared with that by traditional single-shot echo-planar imaging (ss-EPI), and ADC measurement was performed on the rs-EPI based ADC maps. Differences in ADC values of tumors grouped according to differentiation grade, clinical T stage and plasmatic carcinoembryonic antigen (CEA) level were tested. The correlation between each aggressive characteristic and the corresponding ADC values was evaluated. The image quality of ADC maps obtained by rs-EPI was superior toss-EPI (P < 0.05). The ADC values of tumor were categorized based on the following differentiation grades: poor (0.89 ± 0.12 × 10-3 mm2/s), moderate (1.13 ± 0.25 × 10-3 mm2/s), and good (1.31 ± 0.19 × 10-3 mm2/s); P < 0.001. Tumors with lower differentiation grades corresponded to lower ADC values (r = 0.59, P < 0.001). However, ADC differences were not observed in different clinical T stage (P = 0.22) and plasmatic CEA level (P = 0.38). Rs-EPI sequence-based ADC values represent a potential imaging marker for the aggressive rectal cancer characteristics.

Noninvasive imaging of hepatocellular carcinoma: From diagnosis to prognosis.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and a major public health problem worldwide. Hepatocarcinogenesis is a complex multistep process at molecular, cellular, and histologic levels with key alterations that can be revealed by noninvasive imaging modalities. Therefore, imaging techniques play pivotal roles in the detection, characterization, staging, surveillance, and prognosis evaluation of HCC. Currently, ultrasound is the first-line imaging modality for screening and surveillance purposes. While based on conclusive enhancement patterns comprising arterial phase hyperenhancement and portal venous and/or delayed phase wash-out, contrast enhanced dynamic computed tomography and magnetic resonance imaging (MRI) are the diagnostic tools for HCC without requirements for histopathologic confirmation. Functional MRI techniques, including diffusion-weighted imaging, MRI with hepatobiliary contrast agents, perfusion imaging, and magnetic resonance elastography, show promise in providing further important information regarding tumor biological behaviors. In addition, evaluation of tumor imaging characteristics, including nodule size, margin, number, vascular invasion, and growth patterns, allows preoperative prediction of tumor microvascular invasion and patient prognosis. Therefore, the aim of this article is to review the current state-of-the-art and recent advances in the comprehensive noninvasive imaging evaluation of HCC. We also provide the basic key concepts of HCC development and an overview of the current practice guidelines.

[Diagnostic Performance of Susceptibility-weighted Imaging in the Grading of Hepatocellular Carcinoma].

OBJECTIVE: To test the capability of intratumoral susceptibility signal intensity (ITSS) in the differentiation of hepatocellular carcinoma (HCC) grades. METHODS: Retrospective reviews of 53 patients with pathologically proven HCCs were performed. All patients underwent both conventional MRI and SWI examinations. The morphological score of ITSS and the number of ITSS per square centimeter were calculated,then compared among low-grade and high-grade HCCs. Spearman correlation coefficients were determined between the morphological scores of ITSS,the number of ITSS per square centimeter and HCC grades. Receiver operating characteristic (ROC) curve analysiss was performed to determine the diagnostic accuracy for HCC differentiation. RESULTS: The morphological scores of ITSS and the number of ITSS per square centimeter in low-grade HCCs were significantly lower than that in the high-grade HCCs (P<0.05). Spearman correlation coefficient between morphological scores of ITSS and HCC grade was 0.54 (P<0.01),and that between the number of ITSS per square centimeter and HCC grade was 0.38 (P<0.01). In the ROC curve analysis of morphological scores,the AUC was 0.81 (P<0.01) and the optimal sensitivity and specificity were 76%,and 88% respectively with a cut-off of 2. In the ROC curve analysis of the number of ITSS per square centimeter,the area under curve (AUC) was 0.70 (P=0.01) and the optimal sensitivity and specificity were 65%,and 79% respectively with a cut-off of 0.58. CONCLUSION: ITSS of SWI had the potential to differentiate HCC grades.

[The Value of Diffusion Kurtosis Imaging in Predicting Post-surgery Early Recurrence of Hepatocellular Carcinoma].

OBJECTIVE: To determine the value of diffusion kurtosis imaging for predicting one-year early recurrence (ER) of hepatocellular carcinoma (HCC) after curative resection. METHODS: 55 HCC patients were enrolled into this prospective study and received preoperative magnetic resonance (MR) examination including diffusion kurtosis imaging (DKI). The patients were followed up for at least one year after curative resection. The morphological features of HCC were assessed using the conventional contrast-enhanced MR images. Mean diffusivity (MD) and mean kurtosis (MK) were calculated for the intratumoral and peritumoral regions. Univariate and multivariate logistic regression analyses were performed to assess the relative value of these parameters as a potential predictor of ER. Receiver operating characteristic (ROC) curve analyses were used to determine the diagnostic performance of these quantitative parameters. RESULTS: Increased alpha-fetoprotein (AFP), BCLC stage, tumor number (≥2), high grade HCC, peritumoral MK, and decreased peritumoral MD were associated with higher one-year ER of HCC (P<0.05). The multivariate analyses confirmed that high grade HCC 〔odds ratio (OR)=5.37,95% confidence interval (CI):1.01-28.50,P=0.048〕 and increased peritumoral MK (OR=5.38,95%CI:1.53-18.92,P=0.009) were independent risk factors for the ER of HCC. The area under curve was 0.79 (P<0.001) for peritumoral MK, with an optimal sensitivity of 85.2% and specificity of 64.3% at the cut-off of 0.96. CONCLUSIONS: Peritumoral MK has moderate diagnostic performance in predicting ER of HCC. Higher peritumoral MK value in combination with high-grade HCC are potential biomarkers for predicting one-year ER of HCC.

Readout-segmented echo-planar imaging improves the image quality of diffusion-weighted MR imaging in rectal cancer: Comparison with single-shot echo-planar diffusion-weighted sequences.

PURPOSE: To determine whether readout-segmented echo-planar imaging (rs-EPI) diffusion-weighted imaging (DWI) can improve the image quality in patients with rectal cancer compared with single-shot echo-planar imaging (ss-EPI) DWI using 3.0 T magnetic resonance (MR) imaging. MATERIALS AND METHODS: This study was approved by the Institutional Review Board, and informed consent was obtained from all patients. Seventy-one patients with rectal cancer were enrolled in this study. For all patients, both rs-EPI and ss-EPI DWI were performed using a 3T MR scanner. Two radiologists independently assessed the overall image quality, lesion conspicuity, geometric distortion and distinction of anatomical structures. The signal-to-noise ratio (SNR), lesion contrast, contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) were also measured. Comparisons of the quantitative and qualitative parameters between the two sequences were performed using the paired t-test and the Wilcoxon signed rank test. RESULTS: The scores of overall image quality, lesion conspicuity, geometric distortion and distinction of anatomical structures of rs-EPI were all significantly higher than those of ss-EPI (all p<0.05). The SNR and CNR were higher in rs-EPI than those in ss-EPI (all p<0.05). There was no significant difference between ss-EPI and rs-EPI with regard to ROI size and mean ADCs of the tumour (p=0.574 and p=0.479, respectively), but the mean ADC of the normal tissue was higher in rs-EPI than in ss-EPI (1.73±0.30×10(-3)mm(2)/s vs. 1.60±0.31×10(-3)mm(2)/s, p=0.001). CONCLUSIONS: DW imaging based on readout-segmented echo-planar imaging is a clinically useful technique to improve the image quality for the purpose of evaluating lesions in patients with rectal tumours.

[Radiation Dose of Body Surface at Sensitive Organs and Its Protective Precaution in Head CT Scanning:Initial Experience.]

OBJECTIVES: To investigate the radiation dose of body surface at sensitive organs using different protective precaution in head CT scanning. METHODS: The standard phantom received head routine sequence scanning with dual-source computed tomography.The phantoms were scanned with three different protective precaution:group A (without protective clothing),group B (wearing lead collar and cover lead clothes),group C (wearing lead collar and clothes without cuffs).The thermoluminescence dosimeters (TLD) was placed on the body surface corresponding to sensitive organs to measure radiation dose. RESULTS: The volume of CT dose index (CTDIvol) and dose length product (DLP) in group A,B and C were same,44.06 mGy and 634 mGy×cm,respectively.There was no statistic significant difference between group A,B and C of radiation dose in non-protective region (P=0.712).The radiation dose in the neck region under the cover of lead collar in group A,B and C were (2.57 ± 0.65) mGy,(2.30 ± 1.10) mGy and (2.48 ± 0.90) mGy,respectively,without statistic significant difference between groups (P=0.816).However,the radiation dose in abdominal region of group A was (0.66±0.37) mGy,which was significantly higher than that of group B [(0.18 ± 0.18) mGy] and group C [(0.18±0.16) mGy],The radiation dose in dorsal region of group A was (0.55±0.43) mGy,which was significantly higher than that of group B [(0.28±0.22) mGy],while that of group C [(0.14±0.12) mGy] was significantly lower than group B. CONCLUSIONS: Compared to traditional lead coverage,lead collar and cloth can decrease the radiation dose of body surface and sensitive organs in head scan with dual source CT.

[Comparison of the efficacy of gadobutrol and multihance in contrast-enhanced MRI for diagnosis of brain metastasis in lung cancer].

OBJECTIVE: To investigate the diagnostic efficacy of gadobutrol for assessing brain metastases in lung cancer patients in comparison with multihance. METHODS: 21 patients with lung cancer suspected of brain metastasis were enrolled in this study. All patients underwent twice MRI scans on a 3.0T MRI scanner (Siemens MAGENETOM Trio) with 8-channel head coil, first with 0.5 mol/L multihance and then with 1.0 mol/L gadobutrol as contrast agent. The dosage of contrast agent was set at 0.1 mmol/kg body mass. The interval between the two scans was 24-72 hours. The detection and delineation of lesions were evaluated visually. The signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR) of lesion to normal brain white matter and the percentage of lesion enhancement were calculated and compared between the two scans by 2 experienced neuroradiologists. RESULTS: One patient was excluded because he received radiation therapy between the two scans. 15 patients were found to have brain metastases with a total of 35 lesions. There were no statistical differences between the two scans in SNR, CNR and percentage enhancement for both normal brain and lesions (t = 0.545, P = 0.592; t = 1.143, P = 2.267; t = 0.592, P = 0.557; t = 0.473, P = 0.639). CONCLUSION: Half-dose gadobutrol (1.0 mol/L) can achieve the same enhancement effects compared with full-dose multihance (0.5 mol/L).