CT coronary fractional flow reserve based on artificial intelligence using different software: a repeatability study.

OBJECTIVE: This study aims to assess the  consistency of various CT-FFR software, to determine the reliability of current CT-FFR software, and to measure relevant influence factors. The goal is to build a solid foundation of enhanced workflow and technical principles that will ultimately improve the accuracy of measurements of coronary blood flow reserve fractions. This improvement is critical for assessing the level of ischemia in patients with coronary heart disease. METHODS: 103 participants were chosen for a prospective research using coronary computed tomography angiography (CCTA) assessment. Heart rate, heart rate variability, subjective picture quality, objective image quality, vascular shifting length, and other factors were assessed. CT-FFR software including K software and S software are used for CT-FFR calculations. The consistency of the two software is assessed using paired-sample t-tests and Bland-Altman plots. The error classification effect is used to construct the receiver operating characteristic curve. RESULTS: The CT-FFR measurements differed significantly between the K and S software, with a statistical significance of P < 0.05. In the Bland-Altman plot, 6% of the points (14 out of 216) fell outside the 95% consistency level. Single-factor analysis revealed that heart rate variability, vascular dislocation offset distance, subjective image quality, and lumen diameter significantly influenced the discrepancies in CT-FFR measurements between two software programs (P < 0.05). The ROC curve shows the highest AUC for the vessel shifting length, with an optimal cut-off of 0.85 mm. CONCLUSION: CT-FFR measurements vary among software from different manufacturers, leading to potential misclassification of qualitative diagnostics. Vessel shifting length, subjective image quality score, HRv, and lumen diameter impacted the measurement stability of various software.

Multiparametric MR radiomics in brain glioma: models comparation to predict biomarker status.

BACKGROUND: Genotype status of glioma have important significance to clinical treatment and prognosis. At present, there are few studies on the prediction of multiple genotype status in glioma by method of multi-sequence radiomics. The purpose of the study is to compare the performance of clinical features (age, sex, WHO grade, MRI morphological features etc.), radiomics features from multi MR sequence (T2WI, T1WI, DWI, ADC, CE-MRI (contrast enhancement)), and a combined multiple features model in predicting biomarker status (IDH, MGMT, TERT, 1p/19q of glioma. METHODS: In this retrospective analysis, 81 glioma patients confirmed by histology were enrolled in this study. Five MRI sequences were used for radiomic feature extraction. Finally, 107 features were extracted from each sequence on Pyradiomics software, separately. These included 18 first-order metrics, such as the mean, standard deviation, skewness, and kurtosis etc., 14 shape features and second-order metrics including 24 grey level run length matrix (GLCM), 16 grey level run length matrix (GLRLM), 16 grey level size zone matrix (GLSZM), 5 neighboring gray tone difference matrix (NGTDM), and 14 grey level dependence matrix (GLDM). Then, Univariate analysis and LASSO (Least absolute shrinkage and selection operator regression model were used to data dimension reduction, feature selection, and radiomics signature building. Significant features (p < 0.05 by multivariate logistic regression were retained to establish clinical model, T1WI model, T2WI model, T1 + C (T1WI contrast enhancement model, DWI model and ADC model, multi sequence model. Clinical features were combined with multi sequence model to establish a combined model. The predictive performance was validated by receiver operating characteristic curve (ROC analysis and decision curve analysis (DCA). RESULTS: The combined model showed the better performance in some groups of genotype status among some models (IDH AUC = 0.93, MGMT AUC = 0.88, TERT AUC = 0.76). Multi sequence model performed better than single sequence model in IDH, MGMT, TERT. There was no significant difference among the models in predicting 1p/19q status. Decision curve analysis showed combined model has higher clinical benefit than multi sequence model. CONCLUSION: Multi sequence model is an effective method to identify the genotype status of cerebral glioma. Combined with clinical models can better distinguish genotype status of glioma. KEY POINTS: The combined model showed the higher performance compare with other models in predicting genotype status of IDH, MGMT, TERT. Multi sequence model showed a better predictive model than that of a single sequence model. Compared with other models, the combined model and multi sequence model show no advantage in prediction of 1p/19q status.

Therapy response assessment of non-small cell lung cancer using dual-energy computed tomography iodine map.

OBJECTIVE: To investigate feasibility of the quantitative parameters of dual-energy computed tomography (DECT) to assess therapy response in advanced non-small cell lung cancer (NSCLC) compared with the traditional enhanced CT parameters based on the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines. METHODS: Forty-five patients with unresectable locally advanced NSCLC who underwent DECT before and after chemotherapy or concurrent chemoradiotherapy (cCRT) were prospectively enrolled. By comparing baseline studies with follow-up, patients were divided into two groups according to RECIST guidelines as follows: disease control (DC, including partial response and stable disease) and progressive disease (PD). The diameter (D), attenuation, iodine concentration and normalized iodine concentration of arterial and venous phases (ICA, ICv, NICA, NICv) and the percentage of these changes pre- and post-therapy were measured and calculated. The Pearson correlation was used to analyze correlation between various quantitative parameters. The receiver operating characteristic (ROC) curves were used to evaluate accuracy of therapy response prediction. RESULTS: The change percentages of Attenuation (Δ-Attenuation-A and Δ-Attenuation-V), IC (ΔICA and ΔICV) and NIC (ΔNICA and ΔNICV) pre- and post-therapy correlate with the change percentage of D (ΔD). Among these, ΔICA strongly correlates with ΔD (r = 0.793, P < 0.001). The areas under ROC curves generated using Δ-Attenuation-A, ΔICA, and ΔNICA are 0.796, 0.900, and 0.880 with the corresponding cutoff value of 9.096, -15.692, and -4.7569, respectively, which are significantly different (P < 0.001). CONCLUSIONS: The quantitative parameters of DECT iodine map, especially iodine concentration, in arterial phase provides a new quantitative image marker to predict therapy response of patients diagnosed with advanced NSCLC.

MR imaging of epithelial ovarian cancer: a combined model to predict histologic subtypes.

OBJECTIVE: To compare the performance of clinical features, conventional MR image features, ADC value, T2WI, DWI, DCE-MRI radiomics, and a combined multiple features model in predicting the type of epithelial ovarian cancer (EOC). METHODS: In this retrospective analysis, 61 EOC patients were confirmed by histology. Significant features (p < 0.05) by multivariate logistic regression were retained to establish a clinical model, conventional MRI morphological model, ADC model, and traditional model. The radiomics model included FS-T2WI, DWI, and DCE-MRI, and also, a multisequence model was established. A total of 1070 radiomics features of each sequence were extracted; then, univariate analysis and LASSO were used to select important features. Traditional models were combined with a combined radiomics model to establish a mixed model. The predictive performance was validated by receiver operating characteristic curve (ROC) analysis, calibration curve, and decision curve analysis (DCA). A stratified analysis was conducted to compare the differences between the combined radiomics model and the traditional model in identifying early- and late-stage EOC. RESULTS: Traditional models showed the highest performance (AUC = 0.96). The performance of the mixed model (AUC = 0.97) was not significantly different from that of the traditional model. The calibration curve showed that the traditional model had the highest reliability. Stratified analysis showed the potential of the combined radiomics model in the early distinction of the two tumor types. CONCLUSION: The traditional model is an effective tool to distinguish EOC type I/II. Combined radiomics models have the potential to better distinguish EOC types in early FIGO stage disease. KEY POINTS: • The combined radiomics model resulted in a better predictive model than that from a single sequence model. • The traditional model showed higher classification accuracy than the combined radiomics model. • Combined radiomics models have the potential to better distinguish EOC types in early FIGO stage disease.

Assessment of Acute Pulmonary Embolism by Computer-Aided Technique: A Reliability Study.

BACKGROUND Acute pulmonary embolism is one of the most common cardiovascular diseases. Computer-aided technique is widely used in chest imaging, especially for assessing pulmonary embolism. The reliability and quantitative analyses of computer-aided technique are necessary. This study aimed to evaluate the reliability of geometry-based computer-aided detection and quantification for emboli morphology and severity of acute pulmonary embolism. MATERIAL AND METHODS Thirty patients suspected of acute pulmonary embolism were analyzed by both manual and computer-aided interpretation of vascular obstruction index and computer-aided measurements of emboli quantitative parameters. The reliability of Qanadli and Mastora scores was analyzed using computer-aided and manual interpretation. RESULTS The time costs of manual and computer-aided interpretation were statistically different (374.90±150.16 versus 121.07±51.76, P<0.001). The difference between the computer-aided and manual interpretation of Qanadli score was 1.83±2.19, and 96.7% (29 out of 30) of the measurements were within 95% confidence interval (intraclass correlation coefficient, ICC=0.998). The difference between the computer-aided and manual interpretation of Mastora score was 1.46±1.62, and 96.7% (29 out of 30) of the measurements were within 95% confidence interval (ICC=0.997). The emboli quantitative parameters were moderately correlated with the Qanadli and Mastora scores (all P<0.001). CONCLUSIONS Computer-aided technique could reduce the time costs, improve the and reliability of vascular obstruction index and provided additional quantitative parameters for disease assessment.

Correlation Between Dual-Energy Computed Tomography Single Scan and Computed Tomography Perfusion for Pancreatic Cancer Patients: Initial Experience.

OBJECTIVE: The objective of this study was to evaluate the role and limit of iodine maps by dual-energy computed tomography (CT) single scan for pancreatic cancer. METHODS: Thirty patients with suspected solitary pancreatic cancer were enrolled in this study and underwent CT perfusion and iodine maps. The parameters of pancreatic cancer and normal pancreatic tissue were calculated. Pearson correlation and paired t test were used for evaluating 2 techniques. RESULTS: Iodine concentration had a moderate positive correlation with blood flow or blood volume (P < 0.05 for both). All values of iodine concentration and blood flow, iodine concentration, and blood volume had significant positive correlations (P < 0.001 for both). The mean effective dose for CT perfusion and iodine maps had significant difference (8.61 ± 0.00 mSv vs 1.13 ± 0.14 mSv, P < 0.001). CONCLUSIONS: Iodine maps had the potential to replace routine CT perfusion for pancreatic cancer with low radiation dose.

Comparison between coronary plaque 64-slice spiral CT characteristics and risk factors of coronary artery disease patients in Chinese Han population and Mongolian.

UNLABELLED: Objective : To compare the coronary atherosclerotic plaque 64-slice spiral CT characteristics and the risk factors of Han (in Inner Mongolia) and Mongolian coronary artery disease patients. Metho d s: The plaques of 126 Mongolian and 269 Han patients were analyzed by 64-slice spiral CT coronary angiography. Their gender, age, height, body mass, the history of hypertension, diabetes, smoking and family diseases, the levels of triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were compared. RESULTS: The incidence of plaques (P <0.05), the proportion of plaques in the circumflex branch (P <0.05), the proportion of medium-severe lumen stenosis induced by plaques (P <0.05), and the proportion of obstructive plaque involved multi-branch (P <0.05) of the Mongolian patients were higher. The plaque compositions of the two groups did not differ significantly (P> 0.05). The body mass index of the Mongolian patients was higher (P <0.05). The hypertension, diabetes, smoking history, TG, TC, HDL-C and LDL-C of the two groups did not differ significantly (P> 0.05). CONCLUSION: The higher incidence of coronary atherosclerotic plaques and the more severe lesions of the Mongolian patients may be related to their higher body mass index.

Association between extramural vascular invasion and iodine quantification using dual-energy computed tomography of rectal cancer: a preliminary study.

OBJECTIVE: This study aimed to investigate whether histopathological confirmed extramural vascular invasion (EMVI) is associated with quantitative parameters derived from dual-energy computed tomography (DECT) of rectal cancer. METHODS: This retrospective study included patients with rectal cancer who underwent rectal cancer surgery and DECT (including arterial-, venous-, and delay-phase scanning) between November 2019 and November 2020. The EMVI of rectal cancer was confirmed via postoperative pathological results. Iodine concentration (IC), IC normalized to the aorta (NIC), and CT attenuation values of the three phases were measured and compared between patients with and without EMVI. Receiver operating characteristic (ROC) curves were generated to determine the diagnostic performance of these DECT quantitative parameters. RESULTS: Herein, 36 patients (22 men and 14 women) with a mean age of 62 [range, 43-77] years) with (n = 13) and without (n = 23) EMVI were included. Patients with EMVI exhibited significantly higher IC in the venous and delay phases (venous-phase: 2.92 ± 0.6 vs 2.34 ± 0.48; delay-phase: 2.46 ± 0.47 vs 1.88 ± 0.35) and NIC in all the three phases (arterial-phase: 0.31 ± 0.12 vs 0.24 ± 0.06; venous-phase: 0.58 ± 0.11 vs 0.41 ± 0.07; delay-phase: 0.68 ± 0.10 vs 0.46 ± 0.08) than patients without EMVI. Among them, the highest area under the ROC curve (AUC) was obtained in the delay-phase NIC (AUC = 0.983). IC in the arterial-phase and CT attenuation in all the three phases did not significantly differ between patients with and without EMVI (p = 0.205-0.869). CONCLUSION: Iodine quantification using dual-energy CT, especially the NIC of the tumor, differs between the EMVI-positive and EMVI-negative groups and seems to help predict the EMVI of rectal cancer in this preliminary study; however, a larger sample size study is warranted in the future.

Predictive value of CT-based extracellular volume fraction in the preoperative pathologic grading of rectal adenocarcinoma: A preliminary study.

OBJECTIVE: This study aimed to investigate whether the extracellular volume fraction (ECV) determined using enhanced computed tomography (CT) can predict the pathologic grade of rectal adenocarcinoma. METHODS: We prospectively analyzed 43 patients with rectal adenocarcinoma confirmed surgically and pathologically and who had undergone preoperative enhanced CT imaging. The plain, arterial, venous, and balance phase values were recorded, and the absolute contrast-enhanced CT differences ΔS1 = HUarterial phase-HUplain scan, ΔS2 = HUvenous phase-HUplain scan, ΔS3 = HUbalance phase-HUplain scan were obtained. The ECV of the primary lesion was calculated by measuring the CT values of the regions of interest in the plain and balance phases. Patients were allocated to either a low-grade or a high-grade group based on the histologic grading standard for colorectal adenocarcinoma (nonspecial type, World Health Organization 2010 standard). The differences in the parameters between the two groups were evaluated for statistical significance. A receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficiency. RESULTS: The 43 enrolled patients [12 in the high-grade group (27.9%) and 31 in the low-grade group (72.1%)] had an average age of 64.47 years. The arterial phase (P = 0.005) as well as ΔS1 (P = 0.006), ΔS3 (P = 0.021), and ECV (P＜ 0.001) differed significantly between the high-grade and low-grade groups, with ECV (P＜ 0.001) and ΔS3 (P = 0.042) being positively correlated with the pathologic grade and arterial phase (P = 0.025) and ΔS1 (P = 0.005) being negatively correlated. The ROC curve demonstrated that the best efficacy in evaluating the pathologic grade of rectal cancer was achieved by ECV, with an area under the curve of 0.892 (95% confidence interval: 0.757-1.000). The diagnostic threshold was 34.42%, sensitivity was 91.7%, and specificity was 83.9%. CONCLUSION: The use of enhanced CT to obtain ECV is helpful in predicting the pathologic grade of rectal cancer; however, this result has to be confirmed in a study with a larger sample size.

Corrigendum: MRI radiomics predicts progression-free survival in prostate cancer.

[This corrects the article DOI: 10.3389/fonc.2022.974257.].

MRI radiomics predicts progression-free survival in prostate cancer.

Objective: To assess the predictive value of magnetic resonance imaging (MRI) radiomics for progression-free survival (PFS) in patients with prostate cancer (PCa). Methods: 191 patients with prostate cancer confirmed by puncture biopsy or surgical pathology were included in this retrospective study, including 133 in the training group and 58 in the validation group. All patients underwent T2WI and DWI serial scans. Three radiomics models were constructed using univariate logistic regression and Gradient Boosting Decision Tree(GBDT) for feature screening, followed by Cox risk regression to construct a mixed model combining radiomics features and clinicopathological risk factors and to draw a nomogram. The performance of the models was evaluated by receiver operating characteristic curve (ROC), calibration curve and decision curve analysis. The Kaplan-Meier method was applied for survival analysis. Results: Compared with the radiomics model, the hybrid model consisting of a combination of radiomics features and clinical data performed the best in predicting PFS in PCa patients, with AUCs of 0.926 and 0.917 in the training and validation groups, respectively. Decision curve analysis showed that the radiomics nomogram had good clinical application and the calibration curve proved to have good stability. Survival curves showed that PFS was shorter in the high-risk group than in the low-risk group. Conclusion: The hybrid model constructed from radiomics and clinical data showed excellent performance in predicting PFS in prostate cancer patients. The nomogram provides a non-invasive diagnostic tool for risk stratification of clinical patients.

Efficacy and safety of radiofrequency ablation and surgery for hepatocellular carcinoma in patients with cirrhosis: A meta-analysis.

BACKGROUND: The aim of this study was to compare the efficacy and safety of surgical resection (RES) and radiofrequency ablation (RFA) in hepatocellular carcinoma (HCC) patients with cirrhosis and to evaluate short- and long-term clinical outcomes. METHODS: The EMBASE, Cochrane Central Register of Control Trials and Medline databases were searched for comparative studies of RES and RFA in HCC patients with cirrhosis from inception until 30 April 2021. Overall survival (OS), disease-free survival (DFS), local recurrence rate, complication rate, hospitalization duration and operation time were compared between the 2 groups. Begg's funnel plot and Egger's test were performed to assess publication bias. RESULTS: A total of 16 studies met our inclusion criteria, including 1 randomized controlled trial. A total of 3760 patients were included, of which 2007 received RES and 1753 received RFA. The results showed that the 3-year OS rate, 5-year OS rate, 1-year DFS rate and 3-year DFS rate in the RFA group compared with the RES treatment group were significantly lower, and the local recurrence rate in the RFA group was significantly higher than that in the RES group. Compared with the RES group, the RFA group had lower postoperative complication rates, shorter operative times, and no significant difference in hospitalization duration. Subgroup analysis of laparoscopic RFA showed that there was no significant difference in 1- and 5-year OS rates and 3-year and 5-year DFS rates between the 2 groups, while the 3-year OS rates and 1-year DFS rates in the RES group were better than those in the laparoscopic RFA group. CONCLUSION: Surgery is widely applied among HCC patients with cirrhosis, providing acceptable short- and long-term results.

The clinical guiding value of a radiomics model for androgen deprivation therapy for prostate cancer.

OBJECTIVE: Three models were used to evaluate prostate cancer after androgen deprivation therapy (ADT) and to determine the value of detecting residual lesions after treatment. METHODS: We retrospectively analysed patients with prostate cancer who received ADT from January 2018 to June 2019. Patients were divided into ADT responder and ADT non-responder groups, and clinical risk factors were determined. Regions of interest were manually contoured on each slice on fat-saturated-T2-weighted imaging, and radiomic features were extracted. Uni- and multivariate logistic regression were used to establish radiomics, clinical and combined models. RESULTS: There were 23 ADT non-responders and 20 ADT responders. In the clinical model, total prostate-specific antigen concentration and T stage were independent predictors of efficacy (area under the curve (AUC) = 0.774). The characteristics, MinIntensity and Correlation_ angle135_offset4 indicated an effective clinical model (AUC = 0.807). GLCMEntropy_ AllDirection_offset1_SD was the best feature to differentiate residual lesions from the central gland (CG) (Lesion-CG model, AUC = 0.955). Correlation_angle135_offset4, GLCMEntropy_ AllDirection_offset4_SD and GLCMEntropy_AllDirection_offset7_SD differentiated residual lesions from the peripheral zone (PZ) (Lesion-PZ model, AUC = 0.855). The AUC for the combined model was 0.904. CONCLUSIONS: Our models can guide the clinical treatment of patients with different ADT responses. Furthermore, the radiomics model can detect prostate cancer that is non-responsive to ADT.

Multiparameter MRI Radiomics Model Predicts Preoperative Peritoneal Carcinomatosis in Ovarian Cancer.

OBJECTIVES: To evaluate the predictive value of radiomics features based on multiparameter magnetic resonance imaging (MP-MRI) for peritoneal carcinomatosis (PC) in patients with ovarian cancer (OC). METHODS: A total of 86 patients with epithelial OC were included in this retrospective study. All patients underwent FS-T2WI, DWI, and DCE-MRI scans, followed by total hysterectomy plus omentectomy. Quantitative imaging features were extracted from preoperative FS-T2WI, DWI, and DCE-MRI images, and feature screening was performed using a minimum redundancy maximum correlation (mRMR) and least absolute shrinkage selection operator (LASSO) methods. Four radiomics models were constructed based on three MRI sequences. Then, combined with radiomics characteristics and clinicopathological risk factors, a multi-factor Logistic regression method was used to construct a radiomics nomogram, and the performance of the radiomics nomogram was evaluated by receiver operating characteristic curve (ROC) curve, calibration curve, and decision curve analysis. RESULTS: The radiomics model from the MP-MRI combined sequence showed a higher area under the curve (AUC) than the model from FS-T2WI, DWI, and DCE-MRI alone (0.846 vs. 0.762, 0.830, 0.807, respectively). The radiomics nomogram (AUC=0.902) constructed by combining radiomics characteristics and clinicopathological risk factors showed a better diagnostic effect than the clinical model (AUC=0.858) and the radiomics model (AUC=0.846). The decision curve analysis shows that the radiomics nomogram has good clinical application value, and the calibration curve also proves that it has good stability. CONCLUSION: Radiomics nomogram based on MP-MRI combined sequence showed good predictive accuracy for PC in patients with OC. This tool can be used to identify peritoneal carcinomatosis in OC patients before surgery.

Ultra-low dose one-step CT angiography for coronary, carotid and cerebral arteries using 128-slice dual-source CT: A feasibility study.

Atherosclerotic diseases are systemic and patient outcomes depend on comprehensive imaging evaluation. Computed tomography angiography (CTA) is a powerful tool used to assess atherosclerosis. However, the scanning protocol is designed for cardiovascular and cerebrovascular imaging, which require considerations into the radiation dose, contrast agent and image quality. The purpose of the present study was to evaluate ultra-low dose one-step CTA for coronary, carotid and cerebral arteries with a low concentration contrast agent. A total of 78 patients were enrolled and randomly divided into two groups: Group A (n=38) and B (n=40). High-pitch CTA for coronary, carotid and cerebral arteries with a tube voltage of 70 or 80 kVp and 40 ml contrast agent (270 mgI/ml) was performed by a 128-slice dual-source CT scanner for group A. Standard high-pitch CTA with a tube voltage of 100 kVp and 60 ml contrast agent (370 mgI/ml) was conducted for group B. The image quality, radiation dose and amount of contrast agent in group A were evaluated and compared with group B. The dose length product for groups A and B was 62.95±21.54 vs. 160.15±15.13 mGy cm, respectively (t=-23.157, P<0.001). The mean total iodine content was 10.8±0 mg for group A and 22.2±0 mg for group B. In total, 99.4% of the arterial segments could be assessed for the two groups (χ 2=0.267, P=0.606). The results revealed that ultra-low dose one-step high-pitch CTA can provide assessable image quality, and minimize the radiation dose and contrast agent.

Large-scale cortical volume correlation networks reveal disrupted small world patterns in Parkinson's disease.

To date, the most frequently reported neuroimaging biomarkers in Parkinson's disease (PD) are direct brain imaging measurements focusing on local disrupted regions. However, the notion that PD is related to abnormal functional and structural connectivity has received support in the past few years. Here, we employed graph theory to analyze the structural co-variance networks derived from 50 PD patients and 48 normal controls (NC). Then, the small world properties of brain networks were assessed in the structural networks that were constructed based on cortical volume data. Our results showed that both the PD and NC groups had a small world architecture in brain structural networks. However, the PD patients had a higher characteristic path length and clustering coefficients compared with the NC group. With regard to the nodal centrality, 11 regions, including 3 association cortices, 5 paralimbic cortices, and 3 subcortical regions were identified as hubs in the PD group. In contrast, 10 regions, including 7 association cortical regions, 2 paralimbic cortical regions, and the primary motor cortex region, were identified as hubs. Moreover, the regional centrality was profoundly affected in PD patients, including decreased nodal centrality in the right inferior occipital gyrus and the middle temporal gyrus and increased nodal centrality in the right amygdala, the left caudate and the superior temporal gyrus. In addition, the structural cortical network of PD showed reduced topological stability for targeted attacks. Together, this study shows that the coordinated patterns of cortical volume network are widely altered in PD patients with a decrease in the efficiency of parallel information processing. These changes provide structural evidence to support the concept that the core pathophysiology of PD is associated with disruptive alterations in the coordination of large-scale brain networks that underlie high-level cognition.

Ultra-low-dose CT coronary angiography using 128-slice dual source CT with low concentration contrast agent: initial experience.

PURPOSE: To optimize and evaluate an ultra-low-dose (ULD) technique for CT coronary angiography (CTCA). MATERIALS AND METHODS: Eighty-two patients were randomly divided into two groups. ULD and routine CTCA were performed in groups A and B. Image quality, radiation dose and contrast agent were evaluated. RESULTS: The effective dose (ED) was 0.20 ± 0.01 mSv for the ULD technique, a decrease of 87% (t = - 21.182, P < 0.001) compared with the control group. The total iodine content was 8.10 ± 0 g, a decrease of 62% (t = - 73.458, P < 0.001) compared with 21.10 ± 1.15 g for the control group. The assessment rates for both groups were the same (99.26 vs 99.64%, χ 2  = 0.727, P = 0.394). The contrast-to-noise ratio was 19.31 ± 7.95 for group A and 20.73 ± 5.07 for group B: the difference was not statistically significant (t = - 1.678, P = 0.095). CONCLUSION: Using an ultra-low radiation dose and contrast agent technique, while maintaining an assessable image and improving the safety of the medical examination, was a feasible and reliable method for CTCA.

Application of single shot free-breathing fast imaging employing steady state sequence in cardiac magnetic resonance imaging.

OBJECTIVE: To investigate the imaging quality of single shot (SS) fast imaging employing steady state (FIESTA) sequence in contrast-enhanced cardiac magnetic resonance (MR) examination, in comparison with the segmented inversion recovery 2D fast gradient echo (IR FGRE) sequence. MATERIALS AND METHODS: Fifty-two cases with suspected or known heart disease were enrolled in this study, including 24 patients who had enhanced myocardium in myocardial delayed enhancement (MDE). We analyzed the imaging quality of the sequences by measuring the myocardium and blood pool signal-to-noise ratios (SNR) and the contrast-to-noise ratios (CNR) of blood pool relative to normal myocardium and of enhanced myocardium relative to normal myocardium and compared the new sequences with traditional sequence. RESULTS: The scanning time of SS FIESTA was significantly shortened as compared to IR FGRE. The differences in the image quality scores, enhanced myocardium (EM) mass and percentages, SNR(bp), SNR(myo), CNR(myo/bp) and CNR(l/bg) were not statistically significant between SS FIESTA and IR FGRE (P > 0.05). However, the difference in CNR(em/myo) was statistically significant between SS FIESTA and IR FGRE (P < 0.0001), with CNR(em/myo) of IR FGRE higher than SS FIESTA. CONCLUSION: Single shot FIESTA speeded up the acquisition time, halving it to (27.6 ± 1.8 s) instead of 146 + 13.8 s (IR FGRE), it had higher SNR and CNR, and its image quality did not differ significantly from IR FGRE. The SS FIESTA is more suitable for patients with severely heart diseases or those unable to hold breath. 3D IR FGRE sequence had higher SNR(myo) than the others and it is suitable for displaying the subendocardial scar. However, it has more artefacts and poor imaging quality than IR FGRE.

Functional evaluation of normothermic ischemia and reperfusion injury in dog kidney by combining MR diffusion-weighted imaging and Gd-DTPA enhanced first-pass perfusion.

PURPOSE: To evaluate functional alterations of renal ischemia and reperfusion injury using MR diffusion-weighted imaging and dynamic perfusion imaging. MATERIALS AND METHODS: Twelve dogs were randomly divided into four groups. Animal renal ischemia was respectively induced for 30 (group 1), 60 (group 2), 90 (group 3), and 120 (group 4) minutes by left renal artery ligation under anesthesia. Using a 1.5 T MR system, true-FISP, TSE, EPI, and DWI sequences were acquired in five different periods; specifically, pre-ischemia, onset-ischemia, late ischemia, onset-reperfusion, and post-reperfusion. Moreover, a turbo-FLASH sequence (TR/TE/TI/FA = 5.8/3.2/400 msec/10 degrees ) with a temporal resolution of 1.16 seconds was acquired. Signal intensity (SI) was measured in the cortex, outer medulla, and inner medulla of kidney. Apparent diffusion coefficient (ADC) values were calculated, and SI was plotted as a function of time. RESULTS: In all animals, significant SI changes of the left kidney on T2/T2*WI were detected following ischemia-reperfusion insult compared to corresponding values of the right kidney. Following ligation, the ADC values decreased in all layers of the left kidney. Immediately after the release of ligation, ADC values in both outer and inner medulla of the left kidney remained lower than those of the right kidney in those animals which were induced with renal ischemia for 60, 90, and 120 minutes. In all groups, a uniphasic enhancement pattern was observed in the outer and inner medulla of the left kidney, accompanied by a decrease of the area under the curve. CONCLUSION: Our results suggest that MR diffusion-weighted imaging and dynamic perfusion imaging are useful in identifying renal dysfunction following normothermic ischemia and reperfusion injury.