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Objectives: To evaluate the prognostic value of radiomics features based on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) images in patients with cardiac amyloidosis (CA)., Methods: This retrospective study included 120 CA patients undergoing CMR at three institutions. Radiomics features were extracted from global and three different segments (base, mid-ventricular, and apex) of left ventricular (LV) on short-axis LGE images. Primary endpoint was all-cause mortality. The predictive performance of the radiomics features and semi-quantitative and quantitative LGE parameters were compared by ROC. The AUC was used to observe whether Rad-score had an incremental value for clinical stage. The Kaplan-Meier curve was used to further stratify the risk of CA patients., Results: During a median follow-up of 12.9 months, 30% (40/120) patients died. There was no significant difference in the predictive performance of the radiomics model in different LV sections in the validation set (AUCs of the global, basal, middle, and apical radiomics model were 0.75, 0.77, 0.76, and 0.77, respectively; all p > 0.05). The predictive performance of the Rad-score of the base-LV was better than that of the LGE total enhancement mass (AUC:0.77 vs. 0.54, p < 0.001) and LGE extent (AUC: 0.77 vs. 0.53, p = 0.004). Rad-score combined with Mayo stage had better predictive performance than Mayo stage alone (AUC: 0.86 vs. 0.81, p = 0.03). Rad-score (≥ 0.66) contributed to the risk stratification of all-cause mortality in CA., Conclusions: Compared to quantitative LGE parameters, radiomics can better predict all-cause mortality in CA, while the combination of radiomics and Mayo stage could provide higher predictive accuracy., Clinical Relevance Statement: Radiomics analysis provides incremental value and improved risk stratification for all-cause mortality in patients with cardiac amyloidosis., Key Points: • Radiomics in LV-base was superior to LGE semi-quantitative and quantitative parameters for predicting all-cause mortality in CA. • Rad-score combined with Mayo stage had better predictive performance than Mayo stage alone or radiomics alone. • Rad-score ≥ 0.66 was associated with a significantly increased risk of all-cause mortality in CA patients., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: To explore the clinical potential of multiparametric cardiac magnetic resonance (CMR) in evaluating myocardial inflammation in patients with exertional heat illness (EHI)., Methods: This prospective study enrolled 28 males with EHI (18 patients with exertional heat exhaustion (EHE) and 10 with exertional heat stroke (EHS)) and 18 age-matched male healthy controls (HC). All subjects underwent multiparametric CMR, and 9 patients had follow-up CMR measurements 3 months after recovery from EHI. CMR-derived left ventricular geometry, function, strain, native T1, extracellular volume (ECV), T2, T2*, and late gadolinium enhancement (LGE) were obtained and compared among different groups., Results: Compared with HC, EHI patients showed increased global ECV, T2, and T2* values (22.6% ± 4.1 vs. 19.7% ± 1.7; 46.8 ms ± 3.4 vs. 45.1 ms ± 1.2; 25.5 ms ± 2.2 vs. 23.8 ms ± 1.7; all p < 0.05). Subgroup analysis showed that ECV was higher in the EHS patients than those in EHE and HC groups (24.7% ± 4.9 vs. 21.4% ± 3.2, 24.7% ± 4.9 vs. 19.7% ± 1.7; both p < 0.05). Repeated CMR measurements at 3 months after baseline CMR showed persistently higher ECV than HC (p = 0.042)., Conclusions: With multiparametric CMR, EHI patients demonstrated increased global ECV, T2, and persistent myocardial inflammation at 3-month follow-up after EHI episode. Therefore, multiparametric CMR might be an effective method in evaluating myocardial inflammation in patients with EHI., Clinical Relevance Statement: This study showed persistent myocardial inflammation after an exertional heat illness (EHI) episode demonstrated by multiparametric CMR, which is a potential promising method to evaluate the severity of myocardial inflammation and guide return to work, play, or duty in EHI patients., Key Points: • EHI patients showed an increased global extracellular volume (ECV), late gadolinium enhancement, and T2 value, indicating myocardial edema and fibrosis. • ECV was higher in the exertional heat stroke patients than exertional heat exhaustion and healthy control groups (24.7% ± 4.9 vs. 21.4% ± 3.2, 24.7% ± 4.9 vs. 19.7% ± 1.7; both p < 0.05). • EHI patients showed persistent myocardial inflammation with higher ECV than healthy controls 3 months after index CMR (22.3% ± 2.4 vs. 19.7% ± 1.7, p = 0.042)., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: To investigate the predictive value of CT-derived fractional flow reserve (FFR CT ) in anastomosis occlusion after coronary artery bypass graft (CABG) surgery., Methods: Patients undergoing CABG with both pre- and post-operative coronary computed tomographic angiography (CCTA) were retrospectively included. Preoperative CCTA studies were used to evaluate anatomical and FFR CT information of target vessels. A diameter stenosis (DS) ≥ 70% or left main > 50% was considered to be anatomically severe, while FFR CT value ≤ 0.80 be functionally significant. The primary endpoint was anastomosis occlusion evaluated on post-operative CCTA during follow-up. Predictors of anastomosis occlusion were assessed by the multivariate binary logistic regression with generalized estimating equations., Results: A total of 270 anastomoses were identified in 88 enrolled patients. Forty-one anastomoses from 30 patients exhibited occlusion during a follow-up of 15.3 months after CABG. The occluded group had significantly increased prevalence of non-severe DS (58.5% vs. 40.2%; p = 0.023) and non-significant FFR CT (48.8% vs. 10.0%; p < 0.001). Multivariable analysis indicated FFR CT ≤ 0.80 (odds ratio [OR]: 0.10, 95% CI: 0.03-0.33; p < 0.001) and older age (OR: 0.92, 95% CI: 0.87-0.97; p = 0.001) were predictors for bypass patency during follow-up, while myocardial infarction history and anastomosis to a local lesion or bifurcation (all p value < 0.05) were predictors of occlusion. Adding FFR CT into the model based on the clinical and anatomical predictors had an improved AUC of 0.848 (p = 0.005)., Conclusions: FFR CT ≤ 0.80 was associated with a significant risk reduction of anastomosis occlusion after CABG. Preoperative judgment of the hemodynamic significance may improve the CABG surgery strategy and reduce graft failure., Key Points: • FFR CT ≤ 0.80 was associated with a significant risk reduction of anastomosis occlusion after CABG. • The addition of FFR CT into the integrated model including clinical (age and history of myocardial infarction) and anatomical CCTA indicators (local lesion and bifurcation) significantly improved the model performance with an AUC of 0.848 (p = 0.005). • Preoperative judgment of the hemodynamic significance may help improve the decision-making and surgery planning in patients indicated for CABG and significantly reduce graft failure, without an extra radiation exposure and risk of invasive procedure., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: To explore downstream management and outcomes of machine learning (ML)-based CT derived fractional flow reserve (FFR CT ) strategy compared with an anatomical coronary computed tomography angiography (CCTA) alone assessment in participants with intermediate coronary artery stenosis., Methods: In this prospective study conducted from April 2018 to March 2019, participants were assigned to either the CCTA or FFR CT group. The primary endpoint was the rate of invasive coronary angiography (ICA) that demonstrated non-obstructive disease at 90 days. Secondary endpoints included coronary revascularization and major adverse cardiovascular events (MACE) at 1-year follow-up., Results: In total, 567 participants were allocated to the CCTA group and 566 to the FFR CT group. At 90 days, the rate of ICA without obstructive disease was higher in the CCTA group (33.3%, 39/117) than that (19.8%, 19/96) in the FFR CT group (risk difference [RD] = 13.5%, 95% confidence interval [CI]: 8.4%, 18.6%; p = 0.03). The ICA referral rate was higher in the CCTA group (27.5%, 156/567) than in the FFR CT group (20.3%, 115/566) (RD = 7.2%, 95% CI: 2.3%, 12.1%; p = 0.003). The revascularization-to-ICA ratio was lower in the CCTA group than that in the FFR CT group (RD = 19.8%, 95% CI: 14.1%, 25.5%, p = 0.002). MACE was more common in the CCTA group than that in the FFR CT group at 1 year (HR: 1.73; 95% CI: 1.01, 2.95; p = 0.04)., Conclusion: In patients with intermediate stenosis, the FFR CT strategy appears to be associated with a lower rate of referral for ICA, ICA without obstructive disease, and 1-year MACE when compared to the anatomical CCTA alone strategy., Key Points: • In stable patients with intermediate stenosis, ML-based FFR CT strategy was associated with a lower referral ICA rate, a lower normalcy rate of ICA, and higher revascularization-to-ICA ratio than the CCTA strategy. • Compared with the CCTA strategy, ML-based FFR CT shows superior outcome prediction value which appears to be associated with a lower rate of 1-year MACE. • ML-based FFR CT strategy as a non-invasive "one-stop-shop" modality may be the potential to change diagnostic workflows in patients with suspected coronary artery disease., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: To propose a novel functional Coronary Artery Disease-Reporting and Data System (CAD-RADS) category system integrated with coronary CT angiography (CCTA)-derived fractional flow reserve (FFR CT ) and to validate its effect on therapeutic decision and prognosis in patients with coronary artery disease (CAD)., Methods: Firstly, we proposed a novel functional CAD-RADS and evaluated the performance of functional CAD-RADS for guiding treatment strategies with actual clinical treatment as a reference standard in a retrospective multicenter cohort with CCTA and invasive FFR performed in all patients (n = 466). Net reclassification improvement (NRI) of functional CAD-RADS over anatomical CAD-RADS was calculated. Secondly, the prognostic value of functional CAD-RADS in a prospective two-arm cohort (566 [FFR CT arm] vs. 567 [CCTA arm]) was calculated, after a 1-year follow-up, functional CAD-RADS in FFR CT arm (n = 513) and anatomical CAD-RADS in CCTA arm (n = 511) to determine patients at risk of adverse outcomes were compared with a Cox hazard proportional model., Results: Functional CAD-RADS demonstrated superior value over anatomical CAD-RADS (AUC: 0.828 vs. 0.681, p < 0.001) and comparable performance to FFR (AUC: 0.828 vs. 0.848, p = 0.253) in guiding therapeutic decisions. Functional CAD-RADS resulted in the revision of management plan as determined by anatomical CAD-RADS in 30.0% of patients (n = 140) (NRI = 0.369, p < 0.001). Functional CAD-RADS was an independent predictor for 1-year outcomes with indexes of concordance of 0.795 and the corresponding value was 0.751 in anatomical CAD-RADS., Conclusion: The novel functional CAD-RADS gained incremental value in guiding therapeutic decision-making compared with anatomical CAD-RADS and comparable power in 1-year prognosis with anatomical CAD-RADS in a real-world scenario., Key Points: • The novel functional CAD-RADS category system with FFR CT integrated into the anatomical CAD-RADS categories was originally proposed. • The novel functional CAD-RADS category system was validated superior value over anatomical CAD-RADS (AUC: 0.828 vs. 0.681, p < 0.001) in guiding therapeutic decisions and revised management plan in 30.0% of patients as determined by anatomical CAD-RADS (net reclassification improvement index = 0.369, p < 0.001). • Functional CAD-RADS was an independent predictor with an index of concordance of 0.795 and 0.751 in anatomical CAD-RADS for 1-year prognosis of adverse outcomes., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: To map time-dependent cardiac structural and functional change patterns after renal transplantation (KT) using cardiac magnetic resonance (CMR)., Methods: Fifty-three patients with pre-KT and post-KT CMR exams were retrospectively analyzed. Patients were divided into three groups according to the time of post-KT CMR: group 1 (3 months post-KT, n = 16), group 2 (6 months post-KT, n = 21), and group 3 (over 9 months post-KT, n = 16). Twenty-one age- and sex-matched healthy controls (HC) were recruited for the study. CMR-derived left ventricular (LV) volumes, LV mass index (LVMi), LV ejection fraction (LVEF), global radial strain (GRS), global circumferential strain (GCS), global longitudinal strain (GLS), and native T1 value were compared. The association between the changes of CMR parameters was assessed., Results: LVMi post-KT decreased in groups 2 (p < 0.001) and 3 (p = 0.004) but both groups had higher LVMi values compared to HC (both p < 0.001). GLS post-KT was decreased in group 1 (p = 0.021), but slightly increased in group 2 (p = 0.728) and group 3 (p = 0.100) without significant difference. GLS post-KT in group 3 was not different from HC (p = 0.104). LVEF, GRS, and GCS post-KT in groups 2 and 3 significantly increased and showed no significant difference from HC. The post-KT native T1 value in all three groups significantly decreased; however, no group showed any significant difference from HC. The change of LVEF was associated with the change of GCS, GRS, and GLS., Conclusions: Although GRS, GCS, GLS, and native T1 values reversed to normal level, LVMi remained impaired in median 14 months after KT., Key Points: • Kidney transplantation has favorable effects on cardiac structure and function. • In a median 14 months of follow-up after KT, left ventricle strain and native T1 value reversed to normal level while LV mass index (LVMi) did not. Left ventricular hypertrophy may help to explain why KT recipients are still at increased cardiovascular risk. • The reason for the decrease of native T1 value after KT may be more than myocardial fibrosis and needs to be further studied., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: To examine the diagnostic accuracy of machine learning-based coronary CT angiography-derived fractional flow reserve (FFR CT ) in diabetes mellitus (DM) patients., Methods: In total, 484 patients with suspected or known coronary artery disease from 11 Chinese medical centers were retrospectively analyzed. All patients underwent CCTA, FFR CT, and invasive FFR. The patients were further grouped into mild (25~49 %), moderate (50~69 %), and severe (≥ 70 %) according to CCTA stenosis degree and Agatston score < 400 and Agatston score ≥ 400 groups according to coronary artery calcium severity. Propensity score matching (PSM) was used to match DM (n  = 112) and non-DM (n  = 214) groups. Sensitivity, specificity, accuracy, and area under the curve (AUC) with 95 % confidence interval (CI) were calculated and compared., Results: Sensitivity, specificity, accuracy, and AUC of FFR CT were 0.79, 0.96, 0.87, and 0.91 in DM patients and 0.82, 0.93, 0.89, and 0.89 in non-DM patients without significant difference (all p > 0.05) on a per-patient level. The accuracies of FFR CT had no significant difference among different coronary stenosis subgroups and between two coronary calcium subgroups (all p > 0.05) in the DM and non-DM groups. After PSM grouping, the accuracies of FFR CT were 0.88 in the DM group and 0.87 in the non-DM group without a statistical difference (p > 0.05)., Conclusions: DM has no negative impact on the diagnostic accuracy of machine learning-based FFR CT ., Key Points: • ML-based FFR CT has a high discriminative accuracy of hemodynamic ischemia, which is not affected by DM. • FFR CT was superior to the CCTA alone for the detection of ischemia relevance of coronary artery stenosis in both DM and non-DM patients. • Coronary calcification had no significant effect on the diagnostic accuracy of FFR CT to detect ischemia in DM patients., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: To investigate the feasibility and prognostic implications of coronary CT angiography (CCTA) derived fractional flow reserve (FFR CT ) in patients who have undergone stents implantation., Methods: Firstly, the feasibility of FFR CT in stented vessels was validated. The diagnostic performance of FFR CT in identifying hemodynamically in-stent restenosis (ISR) in 33 patients with invasive FFR ≤ 0.88 as reference standard, intra-group correlation coefficient (ICC) between FFR CT and FFR was calculated. Secondly, prognostic value was assessed with 115 patients with serial CCTA scans after PCI. Stent characteristics (location, diameter, length, etc.), CCTA measurements (minimum lumen diameter [MLD], minimum lumen area [MLA], ISR), and FFR CT measurements (FFR CT , ΔFFR CT , ΔFFR CT /stent length) both at baseline and follow-up were recorded. Longitudinal analysis included changes of MLD, MLA, ISR, and FFR CT . The primary endpoint was major adverse cardiovascular events (MACE)., Results: Per-patient accuracy of FFR CT was 0.85 in identifying hemodynamically ISR. FFR CT had a good correlation with FFR (ICC = 0.84). 15.7% (18/115) developed MACE during 25 months since follow-up CCTA. Lasso regression identified age and follow-up ΔFFR CT /length as candidate variables. In the Cox proportional hazards model, age (hazard ratio [HR], 1.102 [95% CI, 1.032-1.177]; p = 0.004) and follow-up ΔFFR CT /length (HR, 1.014 [95% CI, 1.006-1.023]; p = 0.001) were independently associated with MACE (c-index = 0.856). Time-dependent ROC analysis showed AUC was 0.787 (95% CI, 0.594-0.980) at 25 months to predict adverse outcome. After bootstrap validation with 1000 resamplings, the bias-corrected c-index was 0.846., Conclusions: Noninvasive ML-based FFR CT is feasible in patients following stents implantation and shows prognostic value in predicting adverse events after stents implantation in low-moderate risk patients., Key Points: • Machine-learning-based FFR CT is feasible to evaluate the functional significance of in-stent restenosis in patients with stent implantation. • Follow-up △FFR CT along with the stent length might have prognostic implication in patients with stent implantation and low-to-moderate risk after 2 years follow-up. The prognostic role of FFR CT in patients with moderate-to-high or high risk needs to be further studied. • FFR CT might refine the clinical pathway of patients with stent implantation to invasive catheterization., (© 2021. European Society of Radiology.)

Objective: To investigate the utility of coronary CT angiography-derived fractional flow reserve (FFR CT ) and plaque progression in patients undergoing serial coronary CT angiography for predicting major adverse cardiovascular events (MACE)., Methods: This retrospective study evaluated patients suspected or known coronary artery disease who underwent serial coronary CT angiography examinations between January 2006 and December 2017 and followed up until June 2019. The primary endpoint was MACE, defined as acute coronary syndrome, rehospitalization due to progressive angina, percutaneous coronary intervention, or cardiac death. FFR CT and plaque parameters were analyzed on a per-vessel and per-patient basis. Univariable and multivariable COX regression analysis determined predictors of MACE. The prognostic value of FFR CT and plaque progression were assessed in nested models., Results: Two hundred eighty-four patients (median age, 61 years (interquartile range, 54-70); 202 males) were evaluated. MACE was observed in 45 patients (15.8%, 45/284). By Cox multivariable regression modeling, vessel-specific FFR CT ≤ 0.80 was associated with a 2.4-fold increased risk of MACE (HR (95% CI): 2.4 (1.3-4.4); p = 0.005) and plaque progression was associated with a 9-fold increased risk of MACE (HR (95% CI): 9 (3.5-23); p < 0.001) after adjusting for clinical and imaging risk factors. FFR CT and plaque progression improved the prediction of events over coronary artery calcium (CAC) score and high-risk plaques (HRP) in the receiver operating characteristics analysis (area under the curve: 0.70 to 0.86; p = 0.002)., Conclusions: Fractional flow reserve and plaque progression assessed by serial coronary CT angiography predicted the risk of future MACE., Key Points: • Vessel-specific CT angiography-derived fractional flow reserve (FFR CT ) ≤ 0.80 and plaque progression improved the prediction of events over current risk factors. • Major adverse cardiovascular events (MACE) significantly increased with the presence of plaque progression at follow-up stratified by the FFR CT change group., (© 2021. European Society of Radiology.)

Objective: To compare the value of reduced field-of-view (FOV) intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and arterial spin labeling (ASL) for assessing renal allograft fibrosis and predicting long-term dysfunction., Methods: This prospective study included 175 renal transplant recipients undergoing reduced FOV IVIM DWI, ASL, and biopsies. Renal allograft fibrosis was categorized into ci0, ci1, ci2, and ci3 fibrosis according to biopsy results. A total of 83 participants followed for a median of 39 (IQR, 21-42) months were dichotomized into stable and impaired allograft function groups based on follow-up estimated glomerular filtration rate. Total apparent diffusion coefficient (ADC T ), pure diffusion ADC, pseudo-perfusion ADC, perfusion fraction f from IVIM DWI, and renal blood flow (RBF) from ASL were calculated and compared. The area under the receiver operating characteristic curve (AUC) was calculated to assess the diagnostic and predictive performances., Results: RBF was different in ci0 vs ci1 (147.9 ± 46.3 vs 126.0 ± 49.4 ml/min/100 g, p = .02) and ci2 vs ci3 (92.9 ± 46.9 vs 70.8 ± 37.8 ml/min/100 g, p = .03). RBF in the stable group was higher than that in the impaired group (144.73 ± 49.33 vs 102.19 ± 47.58 ml/min/100 g, p < .001). AUCs in distinguishing renal allograft fibrosis and predicting long-term allograft dysfunction for RBF were higher than cortical ADC T (ci0 vs ci1-3, 0.76 vs 0.59, p < .001; ci0-1 vs ci2-3, 0.79 vs 0.68, p = .01; ci0-2 vs ci3, 0.79 vs 0.68, p = .01; 0.76 vs 0.60, p = .04, respectively)., Conclusion: Compared to reduced FOV IVIM DWI, ASL was a more promising technique for noninvasively distinguishing renal allograft fibrosis degree and predicting long-term allograft dysfunction., Key Points: • Compared to total ADC from rFOV IVIM DWI, RBF from ASL can distinguish no fibrosis (ci0) vs mild fibrosis (ci1) (p = .02) and moderate fibrosis (ci2) vs severe fibrosis (ci3) (p = .04). • RBF had superior performance than diffusion parameters in discriminating fibrosis (no fibrosis [ci0] vs fibrosis [ci1-3], mild fibrosis [ci0-1] vs moderate to severe fibrosis [ci2-3], non-severe [ci0-2] vs severe [ci3] fibrosis; AUC = 0.76 vs 0.59, p < .001; 0.79 vs 0.68, p = .01; 0.79 vs 0.68, p = .01). • Compared to reduced FOV IVIM DWI, ASL was a more promising technique for noninvasively predicting long-term allograft dysfunction (AUC = 0.76 vs 0.60, p = .04)., (© 2021. European Society of Radiology.)

Objectives: To develop a deep learning-based method for simultaneous myocardium and pericardial fat quantification from coronary computed tomography angiography (CCTA) for the diagnosis and treatment of cardiovascular disease (CVD)., Methods: We retrospectively identified CCTA data obtained between May 2008 and July 2018 in a multicenter (six centers) CVD study. The proposed method was evaluated on 422 patients' data by two studies. The first overall study involves training model on CVD patients and testing on non-CVD patients, as well as training on non-CVD patients and testing on CVD patients. The second study was performed using the leave-center-out approach. The method performance was evaluated using Dice similarity coefficient (DSC), Jaccard index (JAC), 95% Hausdorff distance (HD95), mean surface distance (MSD), residual mean square distance (RMSD), and the center of mass distance (CMD). The robustness of the proposed method was tested using the nonparametric Kruskal-Wallis test and post hoc test to assess the equality of distribution of DSC values among different tests., Results: The automatic segmentation achieved a strong correlation with contour (ICC and R > 0.97, p value < 0.001 throughout all tests). The accuracy of the proposed method remained high through all the tests, with the median DSC higher than 0.88 for pericardial fat and 0.96 for myocardium. The proposed method also resulted in mean MSD, RMSD, HD95, and CMD of less than 1.36 mm for pericardial fat and 1.00 mm for myocardium., Conclusions: The proposed deep learning-based segmentation method enables accurate simultaneous quantification of myocardium and pericardial fat in a multicenter study., Key Points: • Deep learning-based myocardium and pericardial fat segmentation method tested on 422 patients' coronary computed tomography angiography in a multicenter study. • The proposed method provides segmentations with high volumetric accuracy (ICC and R > 0.97, p value < 0.001) and similar shape as manual annotation by experienced radiologists (median Dice similarity coefficient ≥ 0.88 for pericardial fat and 0.96 for myocardium).

Objective: To investigate the effect of coronary calcification morphology and severity on the diagnostic performance of machine learning (ML)-based coronary CT angiography (CCTA)-derived fractional flow reserve (CT-FFR) with FFR as a reference standard., Methods: A total of 442 patients (61.2 ± 9.1 years, 70% men) with 544 vessels who underwent CCTA, ML-based CT-FFR, and invasive FFR from China multicenter CT-FFR study were enrolled. The effect of calcification arc, calcification remodeling index (CRI), and Agatston score (AS) on the diagnostic performance of CT-FFR was investigated. CT-FFR ≤ 0.80 and lumen reduction ≥ 50% determined by CCTA were identified as vessel-specific ischemia with invasive FFR as a reference standard., Results: Compared with invasive FFR, ML-based CT-FFR yielded an overall sensitivity of 0.84, specificity of 0.94, and accuracy of 0.90 in a total of 344 calcification lesions. There was no statistical difference in diagnostic accuracy, sensitivity, or specificity of CT-FFR across different calcification arc, CRI, or AS levels. CT-FFR exhibited improved discrimination of ischemia compared with CCTA alone in lesions with mild-to-moderate calcification (AUC, 0.89 vs. 0.69, p < 0.001) and lesions with CRI ≥ 1 (AUC, 0.89 vs. 0.71, p < 0.001). The diagnostic accuracy and specificity of CT-FFR were higher than CCTA alone in patients and vessels with mid (100 to 299) or high (≥ 300) AS., Conclusion: Coronary calcification morphology and severity did not influence diagnostic performance of CT-FFR in ischemia detection, and CT-FFR showed marked improved discrimination of ischemia compared with CCTA alone in the setting of calcification., Key Points: • CT-FFR provides superior diagnostic performance than CCTA alone regardless of coronary calcification. • No significant differences in the diagnostic performance of CT-FFR were observed in coronary arteries with different coronary calcification arcs and calcified remodeling indexes. • No significant differences in the diagnostic accuracy of CT-FFR were observed in coronary arteries with different coronary calcification score levels.

Objectives: To utilize a deep learning model for automatic detection of abnormalities in chest CT images from COVID-19 patients and compare its quantitative determination performance with radiological residents., Methods: A deep learning algorithm consisted of lesion detection, segmentation, and location was trained and validated in 14,435 participants with chest CT images and definite pathogen diagnosis. The algorithm was tested in a non-overlapping dataset of 96 confirmed COVID-19 patients in three hospitals across China during the outbreak. Quantitative detection performance of the model was compared with three radiological residents with two experienced radiologists' reading reports as reference standard by assessing the accuracy, sensitivity, specificity, and F1 score., Results: Of 96 patients, 88 had pneumonia lesions on CT images and 8 had no abnormities on CT images. For per-patient basis, the algorithm showed superior sensitivity of 1.00 (95% confidence interval (CI) 0.95, 1.00) and F1 score of 0.97 in detecting lesions from CT images of COVID-19 pneumonia patients. While for per-lung lobe basis, the algorithm achieved a sensitivity of 0.96 (95% CI 0.94, 0.98) and a slightly inferior F1 score of 0.86. The median volume of lesions calculated by algorithm was 40.10 cm 3 . An average running speed of 20.3 s ± 5.8 per case demonstrated the algorithm was much faster than the residents in assessing CT images (all p < 0.017). The deep learning algorithm can also assist radiologists make quicker diagnosis (all p < 0.0001) with superior diagnostic performance., Conclusions: The algorithm showed excellent performance in detecting COVID-19 pneumonia on chest CT images compared with resident radiologists., Key Points: • The higher sensitivity of deep learning model in detecting COVID-19 pneumonia were found compared with radiological residents on a per-lobe and per-patient basis. • The deep learning model improves diagnosis efficiency by shortening processing time. • The deep learning model can automatically calculate the volume of the lesions and whole lung.

Objectives: This study investigated the impact of machine learning (ML)-based fractional flow reserve derived from computed tomography (FFR CT ) compared to invasive coronary angiography (ICA) for therapeutic decision-making and patient outcome in patients with suspected coronary artery disease (CAD)., Methods: One thousand one hundred twenty-one consecutive patients with stable chest pain who underwent coronary computed tomography angiography (CCTA) followed ICA within 90 days between January 2007 and December 2016 were included in this retrospective study. Medical records were reviewed for the endpoint of major adverse cardiac events (MACEs). FFR CT values were calculated using an artificial intelligence (AI) ML platform. Disagreements between hemodynamic significant stenosis via FFR CT and severe stenosis on qualitative CCTA and ICA were also evaluated., Results: After FFR CT results were revealed, a change in the proposed treatment regimen chosen based on ICA results was seen in 167 patients (14.9%). Over a median follow-up time of 26 months (4-48 months), FFR CT ≤ 0.80 was associated with MACE (HR, 6.84 (95% CI, 3.57 to 13.11); p < 0.001), with superior prognostic value compared to severe stenosis on ICA (HR, 1.84 (95% CI, 1.24 to 2.73), p = 0.002) and CCTA (HR, 1.47 (95% CI, 1.01 to 2.14, p = 0.045). Reserving ICA and revascularization for vessels with positive FFR CT could have reduced the rate of ICA by 54.5% and lead to 4.4% fewer percutaneous interventions., Conclusions: This study indicated ML-based FFR CT had superior prognostic value when compared to severe anatomic stenosis on CCTA and adding FFR CT may direct therapeutic decision-making with the potential to improve efficiency of ICA., Key Points: • ML-based FFR CT shows superior outcome prediction value when compared to severe anatomic stenosis on CCTA. • FFR CT noninvasively informs therapeutic decision-making with potential to change diagnostic workflows and enhance efficiencies in patients with suspected CAD. • Reserving ICA and revascularization for vessels with positive FFR CT may reduce the normalcy rate of ICA and improve its efficiency.

Objectives: To build models based on conventional logistic regression (LR) and machine learning (ML) algorithms combining clinical, morphological, and hemodynamic information to predict individual rupture status of unruptured intracranial aneurysms (UIAs), afterwards tested in internal and external validation datasets., Methods: Patients with intracranial aneurysms diagnosed by computed tomography angiography and confirmed by invasive cerebral angiograph or clipping surgery were included. The prediction models were developed based on clinical, aneurysm morphological, and hemodynamic parameters by conventional LR and ML methods., Results: The training, internal validation, and external validation cohorts were composed of 807 patients, 200 patients, and 108 patients, respectively. The area under curves (AUCs) of conventional LR models 1 (clinical), 2 (clinical and aneurysm morphological), and 3 (clinical, aneurysm morphological and hemodynamic characteristics) were 0.608, 0.765, and 0.886, respectively (all p < 0.05). The AUCs of ML models using random forest (RF), multilayer perceptron (MLP), and support vector machine (SVM) were 0.871, 0.851, and 0.863, respectively. There were no difference among AUCs of conventional LR, RF, and SVM (all p > 0.05/6), while the AUC of MLP was lower than that of conventional LR (p = 0.0055)., Conclusion: Hemodynamic parameters play an important role in the prediction performance of the models. ML methods cannot outperform conventional LR in prediction models for rupture status of UIAs integrating clinical, aneurysm morphological, and hemodynamic parameters., Key Points: • The addition of hemodynamic parameters can improve prediction performance for rupture status of unruptured intracranial aneurysms. • Machine learning algorithms cannot outperform conventional logistic regression in prediction models for rupture status integrating clinical, aneurysm morphological, and hemodynamic parameters. • Models integrating clinical, aneurysm morphological, and hemodynamic parameters may help choose the optimal management.

Objective: To investigate the effect of image quality of coronary CT angiography (CCTA) on the diagnostic performance of a machine learning-based CT-derived fractional flow reserve (FFR CT )., Methods: This nationwide retrospective study enrolled participants from 10 individual centers across China. FFR CT analysis was performed in 570 vessels in 437 patients. Invasive FFR and FFR CT values ≤ 0.80 were considered ischemia-specific. Four-score subjective assessment based on image quality and objective measurement of vessel enhancement was performed on a per-vessel basis. The effects of body mass index (BMI), sex, heart rate, and coronary calcium score on the diagnostic performance of FFR CT were studied., Results: Among 570 vessels, 216 were considered ischemia-specific by invasive FFR and 198 by FFR CT . Sensitivity and specificity of FFR CT for detecting lesion-specific ischemia were 0.82 and 0.93, respectively. Area under the curve (AUC) of high-quality images (0.93, n = 159) was found to be superior to low-quality images (0.80, n = 92, p = 0.02). Objective image quality and heart rate were also associated with diagnostic performance of FFR CT , whereas there was no statistical difference in diagnostic performance among different BMI, sex, and calcium score groups (all p > 0.05, Bonferroni correction)., Conclusions: This retrospective multicenter study supported the FFR CT as a noninvasive test in evaluating lesion-specific ischemia. Subjective image quality, vessel enhancement, and heart rate affect the diagnostic performance of FFR CT ., Key Points: • FFR CT can be used to evaluate lesion-specific ischemia. • Poor image quality negatively affects the diagnostic performance of FFR CT . • CCTA with ≥ score 3, intracoronary enhancement degree of 300-400 HU, and heart rate below 70 bpm at scanning could be of great benefit to more accurate FFR CT analysis.

Purpose: This study was conducted in order to investigate the topological organization of functional and structural brain networks in diabetic kidney disease (DKD) and its potential clinical relevance., Methods: Two hundred two subjects (62 DKD patients, 60 diabetes mellitus [DM] patients, and 80 healthy controls) underwent laboratory examination, neuropsychological test, and magnetic resonance imaging (MRI). Large-scale functional and structural brain networks were constructed and graph theoretical network analyses were performed. The effect of renal function on brain functional and structural networks in DKD patients was further evaluated. Correlations were performed between network properties and neuropsychological scores and clinical variables., Results: Progressing deteriorated global and local network topology organizations (especially for functional network) were observed for DKD patients compared with control subjects (all p < 0.05, Bonferroni-corrected), with intermediate values for the patients with DM. DKD patients showed normally appearing functional-structural coupling compared with controls, while DM patients manifested functional-structural decoupling (p < 0.05, Bonferroni-corrected). Impaired kidney function markedly affected functional and structural network organization in DKD patients (all p < 0.05). Urea nitrogen correlated with global and local efficiency in the structural networks (r = - 0.551, p < 0.001; r = - 0.476, p < 0.001, respectively). Global and local efficiency in the structural networks and normalized characteristic path length in the functional networks were associated with information processing speed and/or psychomotor speed., Conclusion: DKD patients showed enhanced functional and structural brain network disruption and normally appearing functional-structural coupling compared with DM patients, which correlated with kidney function, renal toxins, and cognitive performance., Key Points: • DKD patients showed markedly disrupted functional and structural brain network efficiency measures compared with DM patients and healthy controls. • Reduced kidney function clearly deteriorated functional and structural brain networks in DKD patients. • DKD patients displayed normally appearing functional-structural coupling compared with DM patients.

Purpose: To evaluate the feasibility of fractional flow reserve (cFFR) derivation from coronary CT angiography (CCTA) in patients with myocardial bridging (MB), its relationship with MB anatomical features, and clinical relevance., Methods: This retrospective study included 120 patients with MB of the left anterior descending artery (LAD) and 41 controls. MB location, length, depth, muscle index, instance, and stenosis rate were measured. cFFR values were compared between superficial MB (≤ 2 mm), deep MB (> 2 mm), and control groups. Factors associated with abnormal cFFR values (≤ 0.80) were analyzed., Results: MB patients demonstrated lower cFFR values in MB and distal segments than controls (all p < 0.05). A significant cFFR difference was only found in the MB segment during systole between superficial (0.94, 0.90-0.96) and deep MB (0.91, 0.83-0.95) (p = 0.018). Abnormal cFFR values were found in 69 (57.5%) MB patients (29 [49.2%] superficial vs. 40 [65.6%] deep; p = 0.069). MB length (OR = 1.06, 95% CI 1.03-1.10; p = 0.001) and systolic stenosis (OR = 1.04, 95% CI 1.01-1.07; p = 0.021) were the main predictors for abnormal cFFR, with an area under the curve of 0.774 (95% CI 0.689-0.858; p < 0.001). MB patients with abnormal cFFR reported more typical angina (18.8% vs 3.9%, p = 0.023) than patients with normal values., Conclusion: MB patients showed lower cFFR values than controls. Abnormal cFFR values have a positive association with symptoms of typical angina. MB length and systolic stenosis demonstrate moderate predictive value for an abnormal cFFR value . KEY POINTS: • MB patients showed lower cFFR values than controls. • Abnormal cFFR values have a positive association with typical angina symptoms. • MB length and systolic stenosis demonstrate moderate predictive value for an abnormal cFFR value .

Purpose: To evaluate image quality of non-contrast-enhanced magnetic resonance angiography (MRA) and compare transplant renal artery stenosis (TRAS) seen by non-contrast-enhanced MRA with digital subtraction angiography (DSA) as the gold standard., Materials and Methods: 330 patients receiving 369 non-contrast-enhanced MRA examinations from July 2014 to June 2017 were included. Thirty patients received at least two MRA examinations. Image quality was independently assessed by two radiologists. Inter-observer agreement was analyzed. Transplant renal artery anatomy and complications were evaluated and compared with DSA. If possible, accuracy was calculated on a per-artery basis., Results: Good or excellent image quality was found in 95.4 % (352/369) of examinations with good inter-observer agreement (K=0.760). Twenty-two patients with DSA had 28 non-contrast-enhanced MRA examinations within a 2-month period. Of these, 19 patients had TRAS, two patients had pseudoaneurysms, and one patient had a normal transplant renal artery but an occluded external iliac artery. Non-contrast-enhanced MRA correctly detected 19 TRAS and nine normal arteries, giving 96.6 % accuracy on a per-artery basis., Conclusions: Non-contrast-enhanced MRA demonstrates a good depiction of the transplanted renal artery and shows good correlation with DSA in cases where there was TRAS., Key Points: • Good or excellent image quality was found in 95.4 % of examinations. • Non-contrast-enhanced MRA can clearly map transplant renal artery anatomy. • Non-contrast-enhanced MRA is a reliable tool to detect TRAS.

Objectives: To determine whether intravenous iodinated contrast material administration increases the risk of acute kidney injury (AKI) in patients with nephrotic syndrome undergoing contrast-enhanced CT., Methods: Patients with nephrotic syndrome undergoing contrast-enhanced CT were retrospectively identified (n = 701). Control group consisted of patients with nephrotic syndrome receiving non-contrast CT (n = 1053). Two different 1:1 propensity score matching models using three or 10 variables were developed for each estimated glomerular filtration (eGFR) subgroup. Incidence of post-CT AKI for the two groups was assessed and compared by standard AKI criteria and Acute Kidney Injury Network (AKIN) criteria., Results: After matching with three variables, the AKI incidence in the contrast-enhanced CT and non-contrast CT groups was 2.7% vs 2.5% (standard AKI criteria) and 4.2% vs. 6.7% (AKIN criteria) (p = 1.00 and 0.05), respectively. After matching with 10 variables, AKI incidences were 3.1% vs. 2.6% (standard AKI criteria) and 4.1% vs. 7.4% (AKIN criteria) (p = 0.72 and 0.03), respectively. AKI incidences of each eGFR subgroup in the contrast-enhanced CT group were not higher than in the non-contrast CT group (lowest p = 0.46)., Conclusion: Intravenous contrast material administration during CT was not found to be a risk factor for AKI in this large cohort of patients with nephrotic syndrome., Key Points: • AKI incidence of contrast-enhanced CT and non-contrast CT had no difference. • AKI incidences of eGFR subgroup in contrast-enhanced CT were not increased. • Studies without a non-contrast CT control group may overestimate CIN incidence.

Objectives: To assess how the severity of hepatic encephalopathy (HE) affects perfusion and metabolic changes in cirrhotic patients and the association between severity and liver disease and anemia., Methods: The study groups comprised 31 healthy subjects and 33 cirrhotic patients who underwent MR examinations, and blood and neuropsychological tests. Of the cirrhotic patients, 14 were unaffected, and 11 had covert HE (CHE) and 8 overt HE (OHE). Global cerebral blood flow (CBF), oxygen extraction fraction (OEF), and metabolic rate of oxygen (CMRO2) were noninvasively measured by phase-contrast and T2-relaxation-under-spin-tagging MRI. Correlations were performed between MR measurements, hematocrits, ammonia levels, Child-Pugh scores and neuropsychological test scores., Results: Compared with the values in healthy subjects, CBF was higher in unaffected patients, the same in CHE patients and lower in OHE patients, OEF was higher in all patients, and CMRO2 was the same in unaffected and CHE patients and lower in OHE patients. Hematocrit was negatively correlated with CBF and OEF, but not with CMRO2. Ammonia level was negatively correlated with CBF and CMRO2, and Child-Pugh score was negatively correlated with CMRO2., Conclusions: The severity-associated alterations in cirrhotic patients indicate that homeostasis of oxygen delivery and oxidative metabolism in HE is regulated by multiple mechanisms. These physiological alterations appeared to be associated with the degree of anemia, ammonia level, and liver function., Key Points: • CBF, OEF and CMRO2 did not change monotonically with HE progression. • Anemia possibly contributed to CBF and OEF changes in cirrhotic patients. • Liver dysfunction mainly contributed to changes in CMRO2 in cirrhotic patients.

Purpose: To evaluate the features and trends of Radiology research in Mainland China through bibliometric analysis of the original articles published in Radiology and European Radiology (ER) between 2006 and 2015., Materials and Methods: We reviewed the original articles published in Radiology and ER between 2006 and 2015. The following information was abstracted: imaging subspecialty, imaging technique(s) used, research type, sample size, study design, statistical analysis, study results, funding declarations, international collaborations, number of authors, department and province of the first author. All variables were examined longitudinally over time., Results: Radiology research in Mainland China saw a substantial increase in original research articles published, especially in the last 5 years (P < 0.001). Within Mainland China's Radiology research, neuroradiology, vascular/interventional Radiology, and abdominal Radiology were the most productive fields; MR imaging was the most used modality, and a distinct geographic provenience was observed for articles published in Radiology and ER., Conclusion: Radiology research in Mainland China has seen substantial growth in the past 5 years with neuroradiology, vascular/interventional Radiology, and abdominal Radiology as the most productive fields. MR imaging is the most used modality. Article provenience shows a distinct geographical pattern., Key Points: • Radiology research in Mainland China saw a substantial increase. • Neuroradiology, vascular/interventional Radiology, and abdominal Radiology are the most productive fields. • MRI is the most used modality in Mainland China's Radiology research. • Guangdong, Shanghai, and Beijing are the most productive provinces.

Objective: To evaluate the diagnostic accuracy of digital subtraction CT angiography (DS-CTA) in detecting posterior inferior cerebellar artery (PICA) aneurysms with digital subtraction angiography (DSA) as reference standard., Methods: A total of 115 patients, including 56 patients diagnosed with PICA aneurysms by CTA or DSA and 59 non-PICA-aneurysm patients were included in this retrospective study. All patients underwent DS-CTA and DSA. The site of PICA aneurysms and the pattern of haemorrhage were analysed. Sensitivity and specificity of DS-CTA without and with combining haemorrhage pattern in diagnosing PICA aneurysms were evaluated on a per patient and per aneurysm basis with DSA., Results: Of 115 patients, 56 patients (48.7%) had 61 PICA aneurysms (size range, 1.1-13.5 mm; mean size, 4.9 ± 2.8 mm) on DSA. The sensitivity and specificity in depicting PICA aneurysms were 89.3% and 96.6% on a per patient basis and 90.2% and 93.4% on a per aneurysm basis, while the corresponding values were 94.6% and 96.6% on a per patient basis and 95.1% and 93.4% on a per aneurysm basis when combining with haemorrhage site., Conclusion: DS-CTA has a high sensitivity and specificity in detecting PICA aneurysms compared with DSA. It may be helpful for clinical diagnosis of PICA aneurysms to combine with haemorrhage sites., Key Points: • CT angiography has a good diagnostic performance in detecting PICA aneurysms. • The haemorrhage location is helpful to detect PICA aneurysms. • Digital subtraction CTA is a preferable diagnostic means for PICA aneurysms.

Purpose: To investigate whether dynamic contrast -enhanced MRI (DCE-MRI) can distinguish the type of liver nodules in a rat model with N-nitrosodiethylamine- induced cirrhosis., Methods: Liver nodules in cirrhosis were induced in 60 male Wistar rats via 0.01 % N-nitrosodiethylamine in the drinking water for 35-100 days. The nodules were divided into three groups: regenerative nodule (RN), dysplastic nodule (DN), and hepatocellular carcinoma (HCC). DCE-MRI was performed, and parameters including transfer constant (K trans ), rate constant (K ep ), extravascular extracellular space volume fraction (V e ), and initial area under the contrast concentration versus time curve (iAUC) were measured and compared., Results: The highest K trans and iAUC values were seen in HCC, followed by DN and RN (all P < 0.05). The area under the receiver operating characteristic curve (AUROC) for DN and HCC were 0.738 and 0.728 for K trans and iAUC, respectively. The AUROC for HCC were 0.850 and 0.840 for K trans and iAUC, respectively. Ordinal logistic regression analysis showed that K trans had a high goodness of fit (0.970, 95 % confidence interval, 13.751-24.958)., Conclusion: DCE-MRI is a promising method to differentiate of liver nodules. Elevated K trans suggested that the nodules may be transformed into HCC., Key Points: • DCE-MRI is promising for differentiating among RN, DN, and HCC • K trans and iAUC positively correlated with malignancy degree of liver nodules • Elevated K trans suggests that the nodules may be transformed into HCC.

Objectives: To evaluate the use of dual-energy CT imaging of the lung perfused blood volume (PBV) for the detection of pulmonary fat embolism (PFE)., Methods: Dual-energy CT was performed in 24 rabbits before and 1 hour, 1 day, 4 days and 7 days after artificial induction of PFE via the right ear vein. CT pulmonary angiography (CTPA) and lung PBV images were evaluated by two radiologists, who recorded the presence, number, and location of PFE on a per-lobe basis. Sensitivity, specificity, and accuracy of CTPA and lung PBV for detecting PFE were calculated using histopathological evaluation as the reference standard., Results: A total of 144 lung lobes in 24 rabbits were evaluated and 70 fat emboli were detected on histopathological analysis. The overall sensitivity, specificity and accuracy were 25.4 %, 98.6 %, and 62.5 % for CTPA, and 82.6 %, 76.0 %, and 79.2 % for lung PBV. Higher sensitivity (p < 0.001) and accuracy (p < 0.01), but lower specificity (p < 0.001), were found for lung PBV compared with CTPA. Dual-energy CT can detect PFE earlier than CTPA (all p < 0.01)., Conclusion: Dual-energy CT provided higher sensitivity and accuracy in the detection of PFE as well as earlier detection compared with conventional CTPA in this animal model study., Key Points: • Fat embolism occurs commonly in patients with traumatic bone injury. • Dual-energy CT improves diagnostic performance for pulmonary fat embolism detection. • Dual-energy CT can detect pulmonary fat embolism earlier than CTPA.

Purpose: To evaluate image quality and diagnostic accuracy for acute infarct detection and radiation dose of 70 kVp whole brain CT perfusion (CTP) and CT angiography (CTA) reconstructed from CTP source data., Methods: Patients were divided into three groups (n = 50 each): group A, 80 kVp, 21 scanning time points; groups B, 70 kVp, 21 scanning time points; group C, 70 kVp, 17 scanning time points. Objective and subjective image quality of CTP and CTA were compared. Diagnostic accuracy for detecting acute infarct and cerebral artery stenosis ≥ 50 % was calculated for CTP and CTA with diffusion weighted imaging and digital subtraction angiography as reference standards. Effective radiation dose was compared., Results: There were no differences in any perfusion parameter value between three groups (P > 0.05). No difference was found in subjective image quality between three groups (P > 0.05). Diagnostic accuracy for detecting acute infarct and vascular stenosis showed no difference between three groups (P > 0.05). Compared with group A, radiation doses of groups B and C were decreased by 28 % and 37 % (both P < 0.001), respectively., Conclusion: Compared with 80 kVp protocol, 70 kVp brain CTP allows comparable vascular and perfusion assessment and lower radiation dose while maintaining high diagnostic accuracy in detecting acute infarct., Key Points: • 70 kVp whole brain CTP can provide diagnostic image quality. • 70 kVp CTP diagnostic accuracy was maintained vs. 80 kVp protocol. • 70 kVp CTP radiation doses were lower than 80 kVp protocol.

Unlabelled: Imaging plays an increasingly important role in the early diagnosis, prognosis prediction and therapy response evaluation of central nervous system (CNS) diseases. The newly emerging hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) can perform "one-stop-shop" evaluation, including anatomic, functional, biochemical and metabolic information, even at the molecular level, for personalised diagnoses and treatments of CNS diseases. However, there are still several problems to be resolved, such as appropriate PET detectors, attenuation correction and so on. This review will introduce the basic physical principles of PET/MRI and its potential clinical applications in the CNS. We also provide the future perspectives for this field., Key Points: • PET/MRI can simultaneously provide anatomic, functional, biochemical and metabolic information. • PET/MRI has promising potential in various central nervous system diseases. • Research on the future implementation of PET/MRI is challenging and encouraging.

Unlabelled: In the past, a high percentage of hospital-acquired renal failure was attributed to contrast media. That position is now very controversial. Recently, doubts have been raised regarding the real relationship between acute kidney injury and intravenous contrast media administration. Similarly, statements about specific methods of preventing contrast-inducing nephropathy have been challenged. This review article addresses the controversies of incidence, causation, and prevention in an attempt to help the practicing radiologist adopt methods for their own department., Key Points: • The reported CIN incidence ranges from 2-12 % following contrast-enhanced CT. • Studies without a non-contrast CT control group may overestimate CIN incidence. • Development and application of a comprehensive CIN prevention strategy is recommended.

Objectives: To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) in young adults with end-stage renal disease (ESRD)., Methods: Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO2 was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores., Results: Compared with controls, ESRD patients had elevated CBF (72.9 ± 12.5 vs. 63.8 ± 8.5 ml min(-1) 100 g(-1), P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO2 (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O2 min(-1) 100 g(-1), P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO2. Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO2. There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059)., Conclusion: Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO2. Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality., Key Points: • Anaemic young adults with ESRD may afford higher CBF and OEF. • Anaemic young adults with ESRD maintain a normal CMRO 2 . • Cognitive function was still impaired in young ESRD adults. • The severity of cognitive dysfunction correlated with CBF and OEF changes.

Purpose: To investigate image quality, radiation dose, and diagnostic performance of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp compared to invasive coronary angiography (ICA) as reference standard., Materials and Methods: Forty-three patients underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp using 30 cc (11 g iodine) contrast medium and ICA. Subjective and objective image quality was evaluated for each CCTA study. CCTA performance for diagnosing ≥50% stenosis was assessed. Results were stratified according to heart rate (HR), body mass index (BMI), Agatston score, and image quality., Results: At CCTA, 94.3% (500/530) of coronary segments were of diagnostic quality. Using ICA as reference standard, sensitivity and accuracy were 100% and 93.0% on a per-patient basis. Per-vessel and per-segment performances were 92.2% and 89.5%; 79.5% and 88.3%, respectively. No differences were found in diagnostic accuracy between different HR, BMI, and calcification subgroups (all P > 0.05) on a per-patient basis. However, low image quality reduced diagnostic accuracy on a per-patient, per-vessel and per-segment basis (all P < 0.05). The mean effective radiation dose was 0.2 ± 0.0 mSv., Conclusion: Our presented protocol results in an effective radiation dose of 0.2 mSv and high diagnostic accuracy for stenosis detection in a selected, non-obese population., Key Points: Prospectively ECG-triggered high-pitch CCTA at 70 kVp is feasible. This protocol has a high diagnostic accuracy for stenosis detection. The mean effective radiation dose was 0.2 ± 0.0 mSv. Only 30 cc of contrast material is used in this protocol. Low image quality reduced diagnostic accuracy of CCTA.

Multidetector computed tomography (CT) plays an important role in the detection, risk stratification and prognosis evaluation of acute pulmonary embolism. This review will discuss the technical improvements for imaging peripheral pulmonary arteries, the methods of assessing pulmonary embolism severity based on CT findings, a multidetector CT technique for pulmonary embolism detection, and lastly, how to avoid overutilization of CT pulmonary angiography and overdiagnosis of pulmonary embolism. Key Points • We describe clinical prediction rules and D-dimers for pulmonary embolism evaluation. • Overutilization of CT pulmonary angiography and overdiagnosis of pulmonary embolism should be avoided. • We discuss technical improvements for imaging peripheral pulmonary arteries. • Pulmonary embolism severity can be assessed based on CT findings. • We discuss multidetector CT techniques for pulmonary embolism detection.

Objectives: To evaluate radiation dose, image quality, and optimal level of sinogram-affirmed iterative reconstruction (SAFIRE) of cerebral CT angiography (CTA) at 70 kVp., Methods: One hundred patients were prospectively classified into two groups: Group A (n = 50), 70 kVp cerebral CTA with 5 levels of SAFIRE reconstruction (S1-S5); and Group B (n = 50), 120 kVp with filtered back projection (FBP) reconstruction. CT attenuation values, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the internal carotid artery (ICA) and middle cerebral artery (MCA) were measured. Subjective image quality was evaluated. Effective dose (ED) was estimated., Results: CT attenuation and noise of the ICA and MCA in Group A were higher than those of Group B (all P < 0.001) while the SNRICA, SNRMCA, CNRICA, and CNRMCA of Group A at S4-5 were comparable to (P > 0.05) or higher than in Group B (P < 0.05). There was no difference in overall image quality between Group A S3-5 and Group B (P > 0.05). ED was 0.2 ± 0.0 mSv for Group A with 85 % ED reduction in comparison to Group B (1.3 ± 0.2 mSv)., Conclusion: Cerebral CTA at 70 kVp is feasible, allowing for substantial radiation dose reduction. SAFIRE S4 level is recommended for obtaining optimal image quality., Key Points: • 70 kVp cerebral CTA is feasible and provides diagnostic image quality. • 70 kVp cerebral CTA resulted in 85% effective dose reduction. • S4 level of SAFIRE is recommended for 70 kVp cerebral CTA.

Objectives: To evaluate the image quality, radiation dose and diagnostic accuracy of 80kVp, high-pitch CT pulmonary angiography (CTPA) with iterative reconstruction using 20 ml of contrast agent., Methods: One hundred patients with suspected pulmonary embolism (PE) were randomly divided into two groups (n = 50 each; group A, 100 kVp, 1.2 pitch, 60 ml of contrast medium and filtered back projection algorithm; group B, 80 kVp, 2.2 pitch, 20 ml of contrast medium and sinogram affirmed iterative reconstruction). Image quality, diagnostic accuracy and radiation dose were evaluated and compared., Results: Mean CT numbers of pulmonary arteries in group B were higher than those in group A (all P < 0.001). Contrast-to-noise ratio and signal-to-noise ratio of group B were higher than those of group A (both P < 0.001). There was no significant difference in subjective image quality scores between two groups (P = 0.807). The interobserver agreement was excellent (k = 0.836). There was no significant difference in diagnostic accuracy between the two groups (P > 0.05). Compared with group A, radiation dose of group B was reduced by 50.3% (P < 0.001)., Conclusions: High-pitch CTPA at 80 kVp can obtain sufficient image quality in normal-weight individuals with 20 ml of contrast agent and half the radiation dose of a conventional CTPA protocol., Key Points: CTPA is feasible at 80 kVp using only 20 ml of contrast agent. High-pitch CTPA at 80 kVp has an effective dose under 1 mSv. This CTPA protocol can obtain sufficient image quality in normal-weight individuals.

Objectives: To evaluate the feasibility, image quality and radiation dose of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) with 30 mL contrast agent at 70 kVp., Methods: Fifty-eight patients with suspected coronary artery disease, a body mass index (BMI) of less than 25 kg/m(2), sinus rhythm and a heart rate (HR) of less than 70 beats per minute (bpm) were prospectively enrolled in this study. Thirty mL of 370 mg I/mL iodinated contrast agent was administrated at a flow rate of 5 mL/s. All patients underwent prospectively ECG-triggered high-pitch CCTA on a second-generation dual-source CT system at 70 kVp using automated tube current modulation., Results: Fifty-six patients (96.6%) had diagnostic CCTA images and two patients (3.4%) had one vessel with poor image quality each rated as non-diagnostic. No significant effects of HR, HR variability and BMI on CCTA image quality were observed (all P > 0.05). Effective dose was 0.17 ± 0.02 mSv and the size-specific dose estimate was 1.03 ± 0.13 mGy., Conclusion: Prospectively ECG-triggered high-pitch CCTA at 70 kVp with 30 mL of contrast agent can provide diagnostic image quality at a radiation dose of less than 0.2 mSv in patients with a BMI of less than 25 kg/m(2) and an HR of less than 70 bpm., Key Points: • Prospectively ECG-triggered high-pitch CCTA at 70 kVp/30 mL contrast agent is feasible. • Diagnostic image quality can be obtained at a radiation dose of less than 0.2 mSv. • This protocol is suitable for normal-weight patients with slow heart rate.

Objectives: To evaluate the image quality, radiation dose and diagnostic accuracy of low kVp and low contrast material volume cerebral CT angiography (CTA) in intracranial aneurysm detection., Methods: One hundred twenty patients were randomly divided into three groups (n = 40 for each): Group A, 70 ml iodinated contrast agent/120 kVp; group B, 30 ml/100 kVp; group C, 30 ml/80 kVp. The CT numbers, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured in the internal carotid artery (ICA) and middle cerebral artery (MCA). Subjective image quality was evaluated. For patients undergoing DSA, diagnostic accuracy of CTA was calculated with DSA as reference standard and compared., Results: CT numbers of ICA and MCA were higher in groups B and C than in group A (P < 0.01). SNR and CNR in groups A and B were higher than in group C (both P < 0.05). There was no difference in subjective image quality among the three groups (P = 0.939). Diagnostic accuracy for aneurysm detection among these groups had no statistical difference (P = 1.00). Compared with group A, the radiation dose of groups B and C was decreased by 45% and 74%., Conclusion: Cerebral CTA at 100 or 80 kVp using 30 ml contrast agent can obtain diagnostic image quality with a low radiation dose while maintaining the same diagnostic accuracy for aneurysm detection., Key Points: • Cerebral CTA is feasible using 100/80 kVp and 30 ml contrast agent. • This approach obtains diagnostic image quality with 45-74% radiation dose reduction. • Diagnostic accuracy for intracranial aneurysm detection seems not to be compromised.

Objectives: Low-grade cerebral oedema is considered to be pathognomonic of minimal hepatic encephalopathy (MHE) in cirrhotic patients. The purpose of this study was to investigate both the grey matter (GM) and white matter (WM) changes in a homogeneous cohort of patients with MHE by combining voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS)., Methods: Twenty-five MHE patients and 25 healthy controls participated in the study with three-dimensional T1 and diffusion-tensor imaging. Group differences in regional GM volume were assessed using VBM analysis while differences in fractional anisotropy (FA), mean diffusivity (MD) of WM were compared using TBSS analysis., Results: VBM displayed extensively decreased GM volume in MHE, mainly located in the frontal and temporal cortices, paracentral lobule, caudate, putamen and amygdale, and increased GM volume in the thalamus. TBSS showed decreased FA in MHE patients in the corpus callosum, cingulum, internal/external capsule, corticospinal tract, superior longitudinal fasciculus and posterior corona radiata. Areas of increased MD in MHE patients were more extensive and included, in addition to all the areas of decreased FA, the anterior corona radiata, inferior fronto-occipital fasciculus, fornix and the middle cerebellar peduncle., Conclusion: The results suggest that cortical atrophy and low-grade brain oedema in WM co-exist in MHE.

Objectives: To evaluate the feasibility and findings of combined dual-energy computed tomography (DECT) lung ventilation/perfusion imaging in patients with suspected pulmonary embolism (PE)., Methods: This study was institutional review board-approved and written informed consent was obtained from each patient. Thirty-two subjects (aged 11-61 years) underwent combined xenon-enhanced ventilation and iodine-enhanced perfusion DECT. Ventilation, perfusion and morphological information were visually interpreted. Ventilation/perfusion information was classified as mismatch (differing patterns) or match (concordant patterns). Adverse reactions and radiation doses were recorded for each subject., Results: Of 32 patients undergoing xenon-enhanced DECT, six patients reported adverse reactions (shortness of breath, n = 2; mild dizziness, n = 3; limb numbness, n = 1). Twenty-eight of 32 patients could be included into the data analysis. PE was detected in 10/28 patients. PE-related ventilation/perfusion mismatch was found in 17 lung lobes in 8/10 patients and matched ventilation/perfusion was detected in 2 patients. Eighteen patients had no PE. In this group, there was no case of a ventilation/perfusion mismatch. Matched ventilation/perfusion impairment was seen in one patient. The overall radiation dose from two DECT acquisitions was 4.8 ± 1.4 mSv (range 2.7-7.5 mSv)., Conclusions: DECT lung ventilation/perfusion imaging is feasible and can visualise ventilation/perfusion match or mismatch in patients with suspected PE., Key Points: • Combined dual-energy CT lung ventilation/perfusion imaging is feasible. • Combined dual-energy CT ventilation/perfusion imaging provides lung morphological and functional information. • Dual-energy CT can demonstrate ventilation/perfusion mismatch in patients with pulmonary embolism.

Purpose: To compare virtual non-enhanced liver CT (VNCT) from dual-energy CT (DECT) with true non-enhanced liver CT (TNCT) in patients., Methods: A total of 102 patients underwent multi-phase abdominal CT. Liver arterial VNCT (VNCT(A)) and portovenous VNCT (VNCT(V)) images were derived from the arterial and portovenous DECT data. The mean CT number, signal to noise ratio (SNR), image quality, contrast to noise (CNR) of liver lesions, lesion detectability and radiation dose were compared., Results: There was no difference in mean CT numbers of all organs (all P>0.05). SNR on VNCT images was higher than that of TNCT (all P<0.001). Image quality of VNCT was diagnostic but lower than that of TNCT (P<0.001). VNCT(A) images were superior to VNCT(V) (P<0.001). VNCT(A) and VNCT(V) detected 78 (91%) and 70 (81%) of 86 hepatic focal lesions visualised on TNCT. There was no difference in the size, attenuation and CNR of focal hepatic lesions (all P>0.05), but SNR of the lesions on VNCT was higher than that on TNCT (P<0.001). Radiation dose of biphase DECT was lower than that of routine triphase CT (P<0.001)., Conclusion: VNCT(A) may potentially replace TNCT as part of a multi-phase liver imaging protocol with consequent saving in radiation dose.

The purpose of the study was to compare the ability of dual energy CT (DECT) and perfusion scintigraphy (PS) to detect pulmonary embolism (PE) in a rabbit model. Gelfoam (n = 20) or saline (n = 4) was injected into the femoral vein of rabbits. After 2 h, DECT pulmonary angiography (CTPA) was used to create blood flow imaging (BFI) and fusion images. The rabbits then underwent PS. Pathological determination of locations and numbers of lung lobes with PE was recorded. The sensitivity and specificity for BFI, CTPA, fused images and PS were calculated using the pathological results as reference standards. Compared with pathological evaluation, CTPA correctly identified PE in 40 lobes and absence of emboli in 80 lobes, corresponding to a sensitivity and specificity of 100%. BFI and fused images correctly identified PE in 40 lobes and the absence of emboli in 78 lobes, corresponding to a sensitivity and specificity of 100% and 98%, respectively. PS correctly detected 27 lobes with PE and 65 lobes without PE, corresponding to a sensitivity and specificity of 68% and 81%, respectively. BFI, CTPA and fused images derived from a single contrast-enhanced DECT provide a higher diagnostic accuracy of detecting PE than PS in a rabbit model.

Objective: To evaluate 16-slice CT portography technique and appearances of cavernous transformation of portal vein (CTPV) and the correlation with surgical procedure of orthotopic liver transplantation (OLT)., Material and Methods: Twenty-four patients with CTPV underwent triphase scanning using a 16-slice CT scanner. Twenty-one of the 24 patients were OLT candidates. After plain scan, enhanced CT scan was performed. The parameters were as follows: thickness of 2.5 mm, reconstruction interval of 1.3 mm, flow rate of 3-4 mL/s, contrast agent of 100 mL, delayed time of 20, 50, and 70 s, respectively. Imaging reformation, including MIP, VR, and SSD, were performed by one radiologist. Two radiologists assessed the thrombosis location and degree, collateral vessels, and superior mesenteric vein (SMV) or splenic vein (SV). The details of collateral vessels, thrombosis location were graded and recorded. One score was partial thrombosis of the main PV; 2 score, complete thrombosis of the main PV; 3 score, complete thrombosis of the main PV plus thrombosis of proximal SV or SMV, and the normal diameter of remaining veins; 4 score, complete thrombosis of the main PV plus thrombosis of more than a half of SV or SMV, and thin diameter of remaining veins; 5 score, complete nonvisualization of the main PV, one or both of SV and SMV, and thin diameter of remaining veins. Thirteen patients thereafter underwent OLT. Operation record was reviewed case by case., Results: All cases obtained MIP images, 16 patients got VR images, and five cases had SSD images. These images can display thrombosis location, degree, and collateral vessels. All patients had hepatopetal collateral vessels. Eleven of the 21 OLT candidates had 1 score, two patients 2 score, four patients 3 score, one patient 4 score, and three patients had 5 score. Fourteen of the 21 candidates were performed end-to-end anastomosis between the donor's and recipient's portal veins, in which 11 patients had 1 score, two patients had 2 score, and two patients 3 score. Both patients with 3 score had normal SV; end-to-end anastomoses were performed between the donor portal vein and recipient SV. Two patients are waiting for donors. OLT was canceled or changed in the six patients with 4 score or 5 score. Correlation coefficient between the score of portal vein and surgical decision was 0.813 (P-value less than 0.001, nonparametric correlation)., Conclusions: Using 16-slice CT portography can noninvasively diagnose CTPV. The appearances of CTPV on the 16-slice CT portography can provide helpful information for surgeons to make an accurate preoperative decision. MIP is the optimal technique for displaying CTPV.