Increased regional Hurst exponent reflects response inhibition related neural complexity alterations in pediatric bipolar disorder patients during an emotional Go-Nogo task

Fractal patterns have been shown to change in resting- and task-state blood oxygen level-dependent signals in bipolar disorder patients. However, fractal characteristics of brain blood oxygen level-dependent signals when responding to external emotional stimuli in pediatric bipolar disorder remain unclear. Blood oxygen level-dependent signals of 20 PBD-I patients and 17 age- and sex-matched healthy controls were extracted while performing an emotional Go-Nogo task. Neural responses relevant to the task and Hurst exponent of the blood oxygen level-dependent signals were assessed. Correlations between clinical indices and Hurst exponent were estimated. Significantly increased activations were found in regions covering the frontal lobe, parietal lobe, temporal lobe, insula, and subcortical nuclei in PBD-I patients compared to healthy controls in contrast of emotional versus neutral distractors. PBD-I patients exhibited higher Hurst exponent in regions that involved in action control, such as superior frontal gyrus, inferior frontal gyrus, inferior temporal gyrus, and insula, with Hurst exponent of frontal orbital gyrus correlated with onset age. The present study exhibited overactivation, increased self-similarity and decreased complexity in cortical regions during emotional Go-Nogo task in patients relative to healthy controls, which provides evidence of an altered emotional modulation of cognitive control in pediatric bipolar disorder patients. Hurst exponent may be a fractal biomarker of neural activity in pediatric bipolar disorder.

[To promote the clinical application of PET/MRI in oncology]

PET/MRI integrates anatomical, functional and metabolic information, and is increasingly used in the field of clinical oncology, including early diagnosis of disease, local staging, detection of systemic metastases, evaluation of treatment efficacy and prognosis. In addition to fine anatomical structure, MRI multiparametric imaging can also provide functional information of the lesion. Combined with metabolic information of PET, MRI multiparametric imaging can better evaluate the benign and maligant lesions, tumor grade and extent of invasion, and identify tumor recurrence and radiation necrosis. The development of new PET tracers, optimization of MRI sequences and examination paths, combined with high-throughput image quantitative analysis methods, radiomics, artificial intelligence and other new technologies will further promote the application of PET/MRI in oncology.

[Qualitative and quantitative PET/MRI in the evaluation of axillary lymph node metastasis in patients with breast cancer]

Objective: To investigate the value of qualitative and quantitative PET/MRI in the evaluation of axillary lymph node metastasis in patients with breast cancer. Methods: A total of 33 patients with breast cancer underwent preoperative PET/MRI examinations in Jingling Hospital from February to August in 2022 were retrospectively collected. All these patients were female, aged from 34 to 73 (51.4±11.3) years. Histopathological results and follow-up data were deemed as the referent standard, and the images were independently evaluated by two experienced breast imaging radiologists. The qualitative PET/MRI evaluation procedures were designed to evaluated the MRI alone to classify the axillary lymph nodes firstly, and then, the axillary lymph nodes status was reclassified by combining MRI and PET images. The net reclassification improvement index (NRI) was calculated using the R Programming Language (RStudio). The quantitative PET/MRI evaluation of the maximum standard uptake value (SUVmax) of axillary lymph nodes were measured by two radiologists, respectively, and the average value was compared with the referent standard to conduct a receiver operating characteristic (ROC) curve to select the optimal cutoff value of SUVmax. Based on the cutoff value and MRI classification results, axillary lymph nodes status was divided into quantitative PET/MRI positive or negative. The sensitivity, specificity and accuracy of MRI and quantitative PET/MRI in evaluating axillary lymph node metastasis were compared, and the area under the ROC curve (AUC) was compared. Results: There was no significant difference in sensitivity, specificity and accuracy between MRI and quantitative PET/MRI in evaluating lymph node metastasis of breast cancer (81.82% vs 95.46%; 81.82% vs 100%; 81.82% vs 96.97%) (all P>0.05). The AUC had a statistically significant difference [0.82 (0.65 to 0.93) vs 0.98 (0.85 to 1.00), P=0.026)]. According to the referent standard, in the 11 cases without ipsilateral axillary lymph node metastasis, the SUVmax was 0.83±0.18, while in the 22 cases with ipsilateral axillary lymph node metastasis, the SUVmax was [4.36 (1.77, 5.85)]. Compared with MRI alone, the NRI of qualitative PET/MRI in evaluating lymph node metastasis was 36.36% (P=0.021). Conclusion: Compared with MRI alone, quantitative PET/MRI has a higher AUC for evaluating axillary lymph node metastasis in patients with breast cancer, and qualitative PET/MRI had a better reclassification power in the evaluation of axillary lymph node metastasis.

Burden and distribution of monosodium urate deposition in patients with hyperuricemia and gout: a cross-sectional Chinese population-based dual-energy CT study

Background

To investigate the distribution and burden of monosodium urate (MSU) deposition in hyperuricemia and gout patients with dual-energy computed tomography (DECT).

Methods

A total of 1,936 consecutive patients from January 1, 2009, to September 15, 2017, underwent DECT examinations in Jinling Hospital. Of these, 1,294 patients were excluded due to other clinical diagnoses (n=1,041), inappropriate locations (n=82), poor-quality images (n=105), training cases (n=30) and duplicated data (n=36). Finally, 642 patients were included in this study. We retrospectively analyzed 1,127 DECT examinations in 642 consecutive patients (hyperuricemia group, n=121; gout group, n=521) and recorded the volume and number of MSU deposits. For each anatomical location, we recorded MSU deposition in the soft tissue and joint cavity. MSU deposition was analyzed and compared between groups. For normally distributed data, independent sample t-tests were used for comparison between the two groups. The independent samples nonparametric test was used to analyze nonnormally distributed data.

Results

(I) The burden of MSU deposition in the gout group {volume [0.14 (0.04-1.36)] and numbers [10.00 (5.00-19.00)]} was significantly higher than that {volume [0.08 (0.02-0.47), P=0.003] and numbers [9.50 (2.00-16.00), P=0.01]} in the hyperuricemia group. (II) The burden of MSU deposition in the knees {volume [0.24 (0.01-1.79), P=0.002] and quantity [6.00 (2.00-12.00), P=0.04]} and feet {volume [0.10 (0.04-0.66)] and number [9.00 (5.00-15.00)]} was significantly higher in the gout group than those {knees: the volume [0.03 (0.00-0.27), P=0.002] and the quantity [4.00 (0.00-9.00), P=0.04]; feet: the volume [0.07 (0.02-0.19), P=0.003)] and number [8.00 (2.25-12.00), P=0.04]} in the hyperuricemia group, respectively. (III) In the hyperuricemia group, the volume of MSU deposition was significantly higher in the soft tissues of the knee (0.022±0.042) and ankle (0.062±0.305) than in those (knee: 0.001±0.005, P=0.02; ankle: 0.027±0.234, P=0.02) in the joint cavity.

Conclusions

Although subclinical urate deposition can occur in patients with asymptomatic hyperuricemia, the burden of urate deposition is greater in patients with symptomatic gout, and the distribution is more pronounced in the foot/knee. Thus, more effective patient management and monitoring can be achieved by measuring the burden of MSU deposits in the patient's feet/knees. These data suggest that a threshold for urate crystal volume at typical sites may be required before symptomatic disease develops.

Structural basis of human PRPS2 filaments

BACKGROUND

PRPP synthase (PRPS) transfers the pyrophosphate groups from ATP to ribose-5-phosphate to produce 5-phosphate ribose-1-pyrophosphate (PRPP), a key intermediate in the biosynthesis of several metabolites including nucleotides, dinucleotides and some amino acids. There are three PRPS isoforms encoded in human genome. While human PRPS1 (hPRPS1) and human PRPS2 (hPRPS2) are expressed in most tissues, human PRPS3 (hPRPS3) is exclusively expressed in testis. Although hPRPS1 and hPRPS2 share 95% sequence identity, hPRPS2 has been shown to be less sensitive to allosteric inhibition and specifically upregulated in certain cancers in the translational level. Recent studies demonstrate that PRPS can form a subcellular compartment termed the cytoophidium in multiple organisms across prokaryotes and eukaryotes. Forming filaments and cytoophidia is considered as a distinctive mechanism involving the polymerization of the protein. Previously we solved the filament structures of Escherichia coli PRPS (ecPRPS) using cryo-electron microscopy (cryo-EM) ¹.

RESULTS

Order to investigate the function and molecular mechanism of hPRPS2 polymerization, here we solve the polymer structure of hPRPS2 at 3.08 Å resolution. hPRPS2 hexamers stack into polymers in the conditions with the allosteric/competitive inhibitor ADP. The binding modes of ADP at the canonical allosteric site and at the catalytic active site are clearly determined. A point mutation disrupting the inter-hexamer interaction prevents hPRPS2 polymerization and results in significantly reduced catalytic activity.

CONCLUSION

Findings suggest that the regulation of hPRPS2 polymer is distinct from ecPRPS polymer and provide new insights to the regulation of hPRPS2 with structural basis.

Incremental value of enhanced plaque length for identifying intracranial atherosclerotic culprit plaques: a high-resolution magnetic resonance imaging study

OBJECTIVES

Besides plaque enhancement grade, the incremental value of enhancement-related high-resolution MRI features in defining culprit plaques needs further evaluation. This study was focused on assessing whether plaque enhancement features contribute to culprit plaque identification and further risk stratification.

METHODS

We retrospectively studied patients who experienced an acute ischaemic stroke and transient ischaemic attack due to intracranial atherosclerosis from 2016 to 2022. The enhancement features included enhancement grade, enhanced length, and enhancement quadrant. Associations between plaque enhancement features and culprit plaques, as well as diagnostic value, were investigated using logistic regression and receiver operating characteristic analyses.

RESULTS

Overall, 287 plaques were identified, of which 231 (80.5%) and 56 (19.5%) were classified as culprit and non-culprit plaques, respectively. Comparison of the pre- and post-enhancement images revealed enhanced length longer than the plaque length in 46.32% of the culprit plaques. Multivariate logistic regression showed that enhanced length longer than plaque length (OR 6.77; 95% CI 2.47-18.51) and grade II enhancement (OR 7.00; 95% CI 1.69-28.93) were independently associated with culprit plaques. The area under the curve value for the combination of stenosis and plaque enhancement grade for the diagnosis of culprit plaques was 0.787, which increased significantly to 0.825 on the addition of enhanced length longer than the plaque length (p = 0.026 for DeLong's test).

CONCLUSIONS

Enhanced length longer than the plaque length and grade II enhancement were independently associated with culprit plaques. The combination of the enhanced plaque features resulted in better culprit plaque identification.

Distinguishing Intracranial Diabetes-Related Atherosclerotic Plaques: A High-Resolution Magnetic Resonance Imaging-Based Radiomics Study

INTRODUCTION

Diabetes markedly affects the formation and development of intracranial atherosclerosis. The study was aimed at evaluating whether radiomics features can help distinguish plaques primarily associated with diabetes.

MATERIALS AND METHODS

We retrospectively analyzed patients who were admitted to our center because of acute ischemic stroke due to intracranial atherosclerosis between 2016 and 2022. Clinical data, blood biomarkers, conventional plaque features, and plaque radiomics features were collected for all patients. Odds ratios (ORs) with 95% confidence intervals (CIs) were determined from logistic regression models. The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were used to describe diagnostic performance. The DeLong test was used to compare differences between models.

RESULTS

Overall, 157 patients (115 men; mean age, 58.7 ± 10.7 years) were enrolled. Multivariate logistic regression analysis showed that plaque length (OR: 1.17; 95% CI: 1.07-1.28) and area (OR: 1.13; 95% CI: 1.02-1.24) were independently associated with diabetes. On combining plaque length and area as a conventional model, the AUCs of the training and validation cohorts for identifying diabetes patients were 0.789 and 0.720, respectively. On combining radiomics features on T1WI and contrast-enhanced T1WI sequences, a better diagnostic value was obtained in the training and validation cohorts (AUC: 0.889 and 0.861). The DeLong test showed the model combining radiomics and conventional plaque features performed better than the conventional model in both cohorts (p < 0.05).

CONCLUSIONS

The use of radiomics features of intracranial plaques on high-resolution magnetic resonance imaging can effectively distinguish culprit plaques with diabetes as the primary pathological cause, which will provide new avenues of research into plaque formation and precise treatment.

[Predictive performance for prognosis of aneurysmal subarachnoid hemorrhage with ventricular hemorrhage by imaging combined with clinical and laboratory quantitative index model]

Objective: To explore the predictive performance of image quantitative index model, clinical-laboratory index model and image-clinical multi-dimensional fusion model in predicting the prognosis of patients with aneurysmal subarachnoid hemorrhage (aSAH) with intraventricular hemorrhage (IVH). Methods: A total of 349 patients with aSAH and IVH, including 122 males and 227 females, aged 22 to 85 (59±11) years underwent CT scan in the General Hospital of Eastern Theater Command from January 2010 to December 2019 were used as dataset 1 to construct a prognostic model. A prognostic model was constructed for data set 1, and the functional recovery of patients 12 months after discharge was evaluated using the modified Rankin Scale (mRS). According to the results, those patients were divided into two groups: good outcome group (n=267) and poor outcome group (n=82). In addition, 63 aSAH patients with IVH, including 27 males and 36 females, aged 32 to 87 (61±12) years who were admitted to the General Hospital of Eastern Theater Command from January 2020 to December 2021 were collected as dataset 2 for independent verification of the model, including 30 patients with poor prognosis. Clinical information (age and gender), laboratory indicators (blood routine and blood biochemistry), and imaging quantitative indicators (such as volume, density, shape of each ventricle hemorrhage area outlined and extracted on head CT scan etc.) were recorded for all patients (dataset 1 and 2). The clinical, laboratory and imaging quantitative indicators of dataset 1 were screened by using L1 regularization and multiple logistic regression method was used to construct the clinical-laboratory index model, image quantitative index model and image-clinical multi-dimensional fusion model, according to the weight coefficient of features in the clinical-laboratory index model and image quantitative index model, screen out the main features. The model was trained and internally validated by 5-fold cross-validation. The model was validated independently in dataset 2. Results: The AUC (area under the ROC curve) of clinical-laboratory index model, image quantitative index model and multidimensional fusion model constructed based on dataset 1 were 0.75 (95%CI: 0.69-0.81), 0.68 (95%CI: 0.61-0.74) and 0.86 (95%CI: 0.82-0.91). The Delong test showed that there were statistically significant differences between the performance of the multi-dimensional fusion model and the clinical-laboratory index model or image quantitative index model (all P<0.05). The AUC of clinical-laboratory index model, image quantitative index model and multidimensional fusion model of dataset 2 were 0.79 (95%CI: 0.68-0.91), 0.70 (95%CI: 0.57-0.83) and 0.81 (95%CI: 0.70-0.92). In addition, in the clinical-laboratory index model and imaging quantitative index model constructed based on data 1, age, Hunt-Hess grade on admission, Neutrophil/Lymphocyte (N/L) (the weight coefficients in the clinical-laboratory index model were 1.00, -0.59 and 0.44) and the standard deviation of third ventricle hemorrhage density, minimum hemorrhage density of the fourth ventricle, and left ventricle hemorrhage sphericity (the weight coefficients in the image quantitative index model were -1.00, 0.85 and -0.84) were the main features of the screening. Conclusions: Quantitative imaging indicators of ventricular hemorrhage (standard deviation of third ventricular hemorrhage density, minimum density of fourth ventricular hemorrhage, and left ventricular sphericity) are helpful to predict the poor prognosis of patients with aSAH with ventricular hemorrhage. Dimensional fusion model has greater value in predicting poor prognosis of patients.

Filamentation modulates allosteric regulation of PRPS

Phosphoribosyl pyrophosphate (PRPP) is a key intermediate in the biosynthesis of purine and pyrimidine nucleotides, histidine, tryptophan, and cofactors NAD and NADP. Abnormal regulation of PRPP synthase (PRPS) is associated with human disorders, including Arts syndrome, retinal dystrophy, and gouty arthritis. Recent studies have demonstrated that PRPS can form filamentous cytoophidia in eukaryotes. Here, we show that PRPS forms cytoophidia in prokaryotes both in vitro and in vivo. Moreover, we solve two distinct filament structures of E. coli PRPS at near-atomic resolution using Cryo-EM. The formation of the two types of filaments is controlled by the binding of different ligands. One filament type is resistant to allosteric inhibition. The structural comparison reveals conformational changes of a regulatory flexible loop, which may regulate the binding of the allosteric inhibitor and the substrate ATP. A noncanonical allosteric AMP/ADP binding site is identified to stabilize the conformation of the regulatory flexible loop. Our findings not only explore a new mechanism of PRPS regulation with structural basis, but also propose an additional layer of cell metabolism through PRPS filamentation.

[Characteristics of the white matter involvement sites on MRI in patients with multiple gliomas]

The retrospective study included 122 cases of multiple glioma and 183 cases of single glioma. Of these, there were 74 males and 48 female with multiple gliomas, aged 18 to 83 (53±13) years, and 104 males and 79 females with single gliomas, aged 10 to 84 (51±14) years. A standard spatial-based lesion analysis method was used for constructing a spatially distributed frequency heatmap of multiple gliomas, to observe the characteristics of their white matter invasion sites. The spatial distribution was more frequent in the subventricular zone, corpus callosum and cingulate gyrus in the multiple glioma group compared to the single glioma group (P<0.001).The white matter areas of multiple gliomas were more extensively involved, with more frequent involvement of the conjoined fibers (corpus callosum, P<0.05) and contact fibers (cingulate, dome, 0.05<P<0.10) areas.The spatial distribution of the brain and the white matter invasion of multiple gliomas have certain site specificity.

Structural basis of dynamic P5CS filaments

The bifunctional enzyme Δ¹-pyrroline-5-carboxylate synthase (P5CS) is vital to the synthesis of proline and ornithine, playing an essential role in human health and agriculture. Pathogenic mutations in the P5CS gene (ALDH18A1) lead to neurocutaneous syndrome and skin relaxation connective tissue disease in humans, and P5CS deficiency seriously damages the ability to resist adversity in plants. We have recently found that P5CS forms cytoophidia in vivo and filaments in vitro. However, it is difficult to appreciate the function of P5CS filamentation without precise structures. Using cryo-electron microscopy, here we solve the structures of Drosophila full-length P5CS in three states at resolution from 3.1 to 4.3 Å. We observe distinct ligand-binding states and conformational changes for the GK and GPR domains, respectively. Divergent helical filaments are assembled by P5CS tetramers and stabilized by multiple interfaces. Point mutations disturbing those interfaces prevent P5CS filamentation and greatly reduce the enzymatic activity. Our findings reveal that filamentation is crucial for the coordination between the GK and GPR domains, providing a structural basis for the catalytic function of P5CS filaments.

Radiomics versus Conventional Assessment to Identify Symptomatic Participants at Carotid Computed Tomography Angiography

INTRODUCTION

Carotid computed tomography angiography (CTA) is routinely used for evaluating the atherosclerotic process. Radiomics allows the extraction of imaging markers of lesion heterogeneity and spatial complexity. These quantitative features can be used as the input for machine learning (ML). Therefore, in this study, we aimed to evaluate the diagnostic performance of radiomics-based ML assessment of carotid CTA data to identify symptomatic patients with carotid artery atherosclerosis.

METHODS

In this retrospective study, participants with carotid artery atherosclerosis who underwent carotid CTA and brain magnetic resonance imaging from May 2010 to December 2017 were studied. The participants were grouped into symptomatic and asymptomatic groups according to their recent symptoms (determination of ipsilateral ischemic stroke). Eight conventional plaque features and 2,107 radiomics parameters were extracted from carotid CTA images. A radiomics-based ML model was fitted on the training set, and the radiomics-based ML model and conventional assessment were compared using the area under the curve (AUC) to identify symptomatic participants.

RESULTS

After excluding participants with other stroke sources, 120 patients with 148 carotid arteries were analyzed. Of these 148 carotid arteries, 34 (22.97%) were classified into the symptomatic group. Plaque ulceration (odds ratio [OR] = 0.257; 95% confidence interval [CI], 0.094-0.698) and plaque enhancement (OR = 0.305; 95% CI, 0.094-0.988) were associated with the symptomatic status. Twenty radiomics parameters were chosen to be inputs in the radiomics-based ML model. In the identification of symptomatic participants, the discriminatory value of the radiomics-based ML model was significantly higher than that of the conventional assessment (AUC = 0.858 vs. AUC = 0.706, p = 0.021).

CONCLUSION

Radiomics-based ML analysis improves the discriminatory power of carotid CTA in the identification of recent ischemic symptoms in patients with carotid artery atherosclerosis.

ASPECTS-Based Attenuation Changes on CT Angiography as an Imaging Biomarker to Predict Hemorrhagic Transformation in Acute Ischemic Stroke

INTRODUCTION

Imaging-based early warning indicators and feasible stratification of acute ischemic stroke (AIS) patients with hemorrhagic transformation (HT), especially high-risk patients with parenchymal hematoma (PH), are crucial in determining subsequent treatment strategies. This study combined automated ASPECTS software with noncontrast CT (NCCT) and CTA source image (CTASI) attenuation changes using Hounsfield unit (HU) values to predict HT and PH in patients with AIS.

MATERIALS AND METHODS

We retrospectively enrolled 172 consecutive patients with anterior circulation large-vessel occlusion between 2016 and 2020. Univariate and multivariate logistic regression and receiver operating characteristic (ROC) analyses were used to investigate the relationship between NCCT and CTASI-ASPECTS-HU, as well as other clinical and radiological parameters of HT and PH. Univariate and multivariate logistic regression analyses were performed to explore risk factors for HT or PH, and an ROC curve was used to evaluate their diagnostic values.

RESULTS

A multivariate analysis showed that CTASI-ASPECTS-HU and NIHSS score were independent predictors of HT (CTASI-ASPECTS-HU: odds ratio (OR), 2.22; 95% CI, 1.01-4.92; NIHSS: OR, 1.07; 95% CI, 1.02-1.13) and PH (CTASI-ASPECTS-HU: OR, 6.51; 95% CI, 2.29-18.50; NIHSS: OR, 1.07; 95% CI, 1.01-1.13). According to ROC analysis, CTASI-ASPECTS-HU >0.09 identified HT (area under the curve, 0.70; sensitivity, 70.15%; specificity, 61.90%), and CTASI-ASPECTS-HU >0.10 identified PH (area under the curve, 0.79; sensitivity, 76.19%; specificity, 73.33%). The area under the curve for predicting HT or PH increased when CTASI-ASPECTS-HU was combined with NIHSS score (HT: area under the curve, 0.74; sensitivity, 73.13%; specificity, 70.48%; PH: area under the curve, 0.81; sensitivity, 85.71%; specificity, 72.38%).

CONCLUSION

CTASI-ASPECTS-HU is a reliable radiological predictor of HT and PH in patients with AIS. Its predictive efficacy is moderately improved when combined with NIHSS score.

Cerebrovascular Disease in the Setting of Posterior Reversible Encephalopathy Syndrome

Overlap between the pathogenesis of posterior reversible encephalopathy syndrome and that of cerebrovascular disease can confound their clinical and radiological presentations, posing a diagnostic challenge. This article presents a literature review and discussion of the clinical manifestations, pathological mechanisms, and imaging manifestations of subarachnoid hemorrhage and vasculitis leading to posterior reversible encephalopathy syndrome, coexistence of posterior reversible encephalopathy syndrome with reversible cerebral vasoconstriction syndrome, and hemorrhage and infarction secondary to posterior reversible encephalopathy syndrome. The findings show that posterior reversible encephalopathy syndrome shares some overlapping pathophysiological mechanisms with cerebrovascular disease. Importantly, neuroimaging plays an important role in identifying this entity in a timely manner and differentiating it from other diseases.

[Association of coronary perivascular fat attenuation index, the parameters of plaque and fractional flow reserve]

Objective: To explore the association of coronary perivascular fat attenuation index (FAI), the parameters of plaque and fractional flow reserve (FFR). Methods: A total of 113 patients (with 141 plaques) (78 males and 35 females, age from 40 to 83 years) with stable coronary artery disease were retrospectively collected from Jingling Hospital and Shanghai Sixth People's Hospital. All the patients underwent coronary CT angiography and invasive FFR examinations. The quantitative and qualitative parameters of plaque and vessel (such as the length and volume of plaque, the characteristics of plaque and high-risk plaque) and the FAI around the plaque were measured. The patients were divided into positive FAI group (n=46) and negative FAI group (n=66) according to the standard of whether the threshold of FAI≥ -70 HU. The quantitative indexes, including age, the length and volume of plaque, minimal lumen area (MLA) and FAI, as well as the qualitative indexed, including the characteristics of plaque, the number and characteristic of high-risk plaque and the number of patients and plaque with positive FFR were compared between the two groups. Further, logistic regression analysis was performed to analyze the correlation among myocardial ischemia, age, the length of plaque, minimal lumen area (MLA), FAI and so on. ROC curve was used for evaluating the performance of each parameter. Results: Compared to the negative FAI group, positive FAI group had lower MLA (2.00±1.33 mm² vs 4.13±2.41 mm², P<0.001). The proportion of patients and vessels with FFR<0.75 in positive FAI group were significantly higher than that in negative FAI group (21.3% vs 4.5%, P=0.006; 23.2% vs 8.2%, P=0.016). The FAI between high-risk plaque and non-high-risk plaque had no significant difference (21.2% vs 16.1%, P=0.451). FAI predicted myocardial ischemia (AUC=0.666, P=0.021) and significantly improved the prediction efficiency of complex model(0.915 vs 0.951,P=0.033). Conclusion: Lower MLA and higher incidence of myocardial ischemia were associated with patients with higher FAI. In addition, FAI has a certain prediction efficiency and can provide incremental value for the determination of myocardial ischemia.

[The analysis of structural magnetic resonance imaging manifestation of hippocampus based on voxel and spherical harmonic surface morphometry in mesial temporal lobe epilepsy]

Objective: To compare the hippocampal volume and local surface morphology changes in patients with mesial temporal lobe (mTLE) using the voxel-based morphometry and spherical harmonic methods respectively. Methods: A total of 66 patients (31 males and 35 females, age range from 17 to 48 (28±8) years) with mTLE and 80 age-and gender-matched controls (38 males and 42 females, age range from 19 to 46 (27±7) years) were retrospectively collected from July 2009 to February 2019 at Jinling hospital.. High resolution structural MRI of the whole brain, three-dimensional T₁-weighted data(3DT1) were acquired from each subject. The changes of hippocampal volume and surface morphology were evaluated between mTLE groups and controls for observing the hippocampal atrophy pattern by using voxel-based morphometry and spherical harmonic shape descriptions point distribution model respectively. Pearson correlation analysis was conducted for observing the relationship between the morphological changes of hippocampus and disease duration. Results: Compared with the controls, hippocampal volume on the affected side in patients with mTLE was significantly reduced (Z-score:-1.55±0.57 vs 0.38±0.58, P<0.001) and negatively correlated with disease duration (r=-0.297, P=0.016). Furthermore, surface morphology analysis subtly showed that the atrophy of the affected hippocampus in patients with mTLE mainly located in the head, mesial lateral part and posterior tail of the hippocampus. Their displacement values were negatively correlated with disease duration (r=-0.336, P=0.006) and positively associated with the hippocampal grey matter volume (r=0.336, P=0.006). Conclusions: Voxel-based morphometry analysis reveals a global reduction in hippocampal volume, while the morphological measurement method based on surface shape can describe the local morphological changes of hippocampal atrophy.

[Hemodynamics-based analysis of factors associated with aneurysm rupture in different sides of the internal carotid artery]

Objective: To explore the influence of hemodynamics, morphological and clinical characteristics on rupture risk of the dorsal and non-dorsal internal carotid artery aneurysms (ICAAs). Methods: A total of 111 patients diagnosed with aneurysm by digital subtraction angiography (DSA) or surgery, underwent cranial CT angiography (CTA) were retrospectively collected from January 2010 to December 2016 at the Department of Diagnostic Radiology, Jinling Clinical College of Xuzhou Medical University (General Hospital of Eastern Theater Command). Among them, 41 were males and 70 were females, ranging in age from 32 to 83 (56±11) years old. The patients were divided into the ruptured group (n=54) and unruptured group (n=57) based on the hemorrhagic manifestation on non-enhanced CT images or DSA or surgery of the head. Demographics and the morphological characteristics of the aneurysms were evaluated. Hemodynamic parameters, including wall share stress, wall share stress gradient, and others were obtained in overall using computational fluid dynamics simulation technique. Characteristics were compared between the ruptured and unruptured groups. Logistic regression analysis was applied to evaluate the independent risk factors for rupture, and the hemodynamic characteristics associated with dorsal and non-dorsal aneurysms were analyzed, respectively. Results: Compared with the unruptured group, patients in the ruptured group were younger ((54.2±11.4) years and (58.3±9.9) years, P=0.033), mostly female (74.1% vs 52.6%, P<0.05), with a higher proportion of hypertension (46.3% vs 22.8%, P=0.009). The ruptured internal carotid artery aneurysms (ICAAs) were more frequently located at the dorsal of an arterial arch (57.4% vs 36.8%, P<0.05), and the flow of the blood was more complex, concentrated, unstable, and with a smaller impingement zone (68.5% vs 33.3%,55.6% vs 10.5%,72.2% vs 26.3% and 79.6% vs 36.8%, respectively, all P<0.05). Logistic regression demonstrated that women, hypertension, dorsal, concentrated flow pattern, and unstable flow pattern were an independent risk factors for ICAAs rupture [OR=3.551 (1.080-11.679), 3.900 (1.172-12.976), 4.966 (1.504-16.401), 51.893 (7.913-340.296) and 50.015 (8.423-296.985), respectively, all P<0.05]. The ruptured ICAAs located at non-dorsal had more concentrated, unstable, and with smaller impingement zone (P<0.05), while those at dorsal had more complex, concentrated, and unstable flow patterns, and with smaller impingement zone (all P<0.05). Conclusion: Women, hypertension, dorsal concentration, and unstable flow pattern are independent risk factors for the rupture of ICAAs. The dorsal locations of ICAAs could have a higher risk of rupture.

ASPECTS-based net water uptake as an imaging biomarker for lesion age in acute ischemic stroke

OBJECTIVE

We assessed the value of computed tomography (CT) and automated Alberta Stroke Program Early CT Score (ASPECTS) with net water uptake (NWU) to predict stroke onset time.

METHODS

Two-hundred forty stroke patients with anterior circulation large-vessel occlusion were included. CT-ASPECTS-NWU values were calculated by comparing the mean Hounsfield units of affected ASPECTS regions with unaffected contralateral regions. The correlation between ASPECTS-NWU and stroke onset to CT time was assessed. ASPECTS-NWU predictive values were calculated to identify a stroke onset to CT time of within 4.5/6 h.

RESULTS

A correlation existed between stroke onset to CT time and ASPECTS-NWU (r = 0.65, p < 0.001), which was affected by collateral status and infarct location. The area under the receiver operating characteristic (ROC) curve (AUC) for distinguishing a stroke onset to CT time of within 4.5 h was 0.837 (95% confidence interval [CI] 0.784-0.881; optimal cutoff 7%; sensitivity 87.10%; specificity 62.36%). The multi-index AUC was 0.884 (95% CI 0.837-0.922). The AUC for distinguishing a stroke onset to CT time of within 6 h was 0.836 (95% CI 0.783-0.880; optimal cutoff 9%; sensitivity 72.73%; specificity 81.16%). The multi-index AUC was 0.881 (95% CI 0.834-0.920).

CONCLUSIONS

ASPECTS-NWU may be used to determine stroke onset time in patients with unwitnessed or wake-up stroke.

Machine Learning-Based Prediction of Small Intracranial Aneurysm Rupture Status Using CTA-Derived Hemodynamics: A Multicenter Study

BACKGROUND AND PURPOSE

Small intracranial aneurysms are being increasingly detected while the rupture risk is not well-understood. We aimed to develop rupture-risk models of small aneurysms by combining clinical, morphologic, and hemodynamic information based on machine learning techniques and to test the models in external validation datasets.

MATERIALS AND METHODS

From January 2010 to December 2016, five hundred four consecutive patients with only small aneurysms (<5 mm) detected by CTA and invasive cerebral angiography (or surgery) were retrospectively enrolled and randomly split into training (81%) and internal validation (19%) sets to derive and validate the proposed machine learning models (support vector machine, random forest, logistic regression, and multilayer perceptron). Hemodynamic parameters were obtained using computational fluid dynamics simulation. External validation was performed in other hospitals to test the models.

RESULTS

The support vector machine performed the best with areas under the curve of 0.88 (95% CI, 0.85-0.92) and 0.91 (95% CI, 0.74-0.98) in the training and internal validation datasets, respectively. Feature ranks suggested hemodynamic parameters, including stable flow pattern, concentrated inflow streams, and a small (<50%) flow-impingement zone, and the oscillatory shear index coefficient of variation, were the best predictors of aneurysm rupture. The support vector machine showed an area under the curve of 0.82 (95% CI, 0.69-0.94) in the external validation dataset, and no significant difference was found for the areas under the curve between internal and external validation datasets (P = .21).

CONCLUSIONS

This study revealed that machine learning had a good performance in predicting the rupture status of small aneurysms in both internal and external datasets. Aneurysm hemodynamic parameters were regarded as the most important predictors.

[Application of deep learning-based chest CT auxiliary diagnosis system in emergency trauma patients]

Objective: To investigate the diagnostic efficacy and potential application value of deep learning-based chest CT auxiliary diagnosis system in emergency trauma patients. Methods: A total of 403 patients, including 254 males and 149 females aged from 16 to 100 (50±19) years, who received emergency treatment for trauma and chest CT examination in the Eastern Theater General Hospital from September 2019 to November 2019 were retrospectively analyzed. Dr. Wise Lung Analyzer's chest CT auxiliary diagnosis system was applied to detect 5 types of injuries, including pneumothorax, pleural effusion/hemothorax, pulmonary contusion (shown as consolidation and ground glass opacity), rib fractures, and other fractures (including thoracic vertebrae, sternum, scapula and clavicle, etc.) and 6 other abnormalities (bullae, emphysema, pulmonary nodules, stripe, reticulation, pleural thickening). The diagnostic reference standards were labeled by two radiologists independently. The sensitivity and specificity of the auxiliary diagnosis system were evaluated. The imaging diagnostic reports were compared with the results of the auxiliary diagnosis system, and the diagnostic consistency between the two was calculated by using the Kappa test. Results: According to the reference standards, among the 403 patients, 29 were pneumothorax, 75 were pleural effusion/hemothorax, 131 were pulmonary contusion, 124 were rib fractures, and 63 were other fractures. The sensitivity and specificity of the auxiliary diagnosis system for detection of pneumothorax, pleural effusion/hemothorax, rib fractures, and other fractures were 96.6%, 97.6%, 80.0%, 99.7%, 99.2%, 83.9%, 84.1%, and 99.7%, respectively. The sensitivity of detecting lung contusion was 97.7%. There was a high consistency between the auxiliary diagnosis system and imaging diagnosis in the diagnosis of injuries, in which the kappa values of pneumothorax, pleural effusion, rib fracture and other fractures were 0.783, 0.821, 0.706 and 0.813, respectively (all P<0.001). Two cases of pneumothorax, three cases of pleural effusion/hemothorax, nine cases of rib fractures, and six cases of other fractures missed by imaging diagnosis were all detected by the auxiliary diagnosis system. The detection sensitivity of the auxiliary diagnosis system was higher for emphysema, pulmonary nodules and stripe (all>85%), but lower for bullae, reticulation and pleural thickening. Conclusions: The deep learning-based chest CT auxiliary diagnosis system could effectively assist chest CT to detect injuries in emergency trauma patients, which was expected to optimize the clinical workflow.

Comparison of automated and manual DWI-ASPECTS in acute ischemic stroke: total and region-specific assessment

OBJECTIVE

To compare the DWI-Alberta Stroke Program Early Computed Tomography Score calculated by a deep learning-based automatic software tool (eDWI-ASPECTS) with the neuroradiologists' evaluation for the acute stroke, with emphasis on its performance on 10 individual ASPECTS regions, and to determine the reasons for inconsistencies between eDWI-ASPECTS and neuroradiologists' evaluation.

METHODS

This retrospective study included patients with middle cerebral artery stroke who underwent MRI from 2010 to 2019. All scans were evaluated by eDWI-ASPECTS and two independent neuroradiologists (with 15 and 5 years of experience in stroke study). Inter-rater agreement and agreement between manual vs. automated methods for total and each region were evaluated by calculating Kendall's tau-b, intraclass correlation coefficient (ICC), and kappa coefficient.

RESULTS

In total, 309 patients met our study criteria. For total ASPECTS, eDWI-ASPECTS and manual raters had a strong positive correlation (Kendall's tau-b = 0.827 for junior raters vs. eDWI-ASPECTS; Kendall's tau-b = 0.870 for inter-raters; Kendall's tau-b = 0.848 for senior raters vs. eDWI-ASPECTS) and excellent agreement (ICC = 0.923 for junior raters and automated scores; ICC = 0.954 for inter-raters; ICC = 0.939 for senior raters and automated scores). Agreement was different for individual ASPECTS regions. All regions except for M5 region (κ = 0.216 for junior raters and automated scores), internal capsule (κ = 0.525 for junior raters and automated scores), and caudate (κ = 0.586 for senior raters and automated scores) showed good to excellent concordance.

CONCLUSION

The eDWI-ASPECTS performed equally well as senior neuroradiologists' evaluation, although interference by uncertain scoring rules and midline shift resulted in poor to moderate consistency in the M5, internal capsule, and caudate nucleus regions.

KEY POINTS

• The eDWI-ASPECTS based on deep learning perform equally well as senior neuroradiologists' evaluations. • Among the individual ASPECTS regions, the M5, internal capsule, and caudate regions mainly affected the overall consistency. • Uncertain scoring rules and midline shift are the main reasons for regional inconsistency.

Reliability and Reproducibility of the Diameters Method in Rapid Determination of Acute Infarct Volume in Magnetic Resonance Diffusion-Weighted Imaging

<b><i>Background:</i></b> In acute ischemic stroke, diffusion-weighted imaging (DWI) volume is an independent predictive factor of poor outcome and an exclusion criterion for thrombolytic treatment. A simplified diameters method (ABC/2, orthogonal diameter [OD], and the maximum diameter [MD]) was proposed to replace the conventional measuring method and overcome the tedious and time-consuming defects, but its accuracy remains to be determined. <b><i>Objective:</i></b> The objective of this study is to clarify the reliability and reproducibility of the diameter-based estimations in the infarct volume in DWI (Vol-DWI) measured by automated software. <b><i>Methods:</i></b> Data of 316 patients with acute ischemic stroke who underwent MRI within 72 h at Jinling Hospital were retrospectively reviewed. Subgroup analysis by the location (cortex, white matter and deep gray nuclei, and combined) and volume (&#x3c;70 and &#x3e;70 mL) of cerebral infarction was evaluated. Relationship and consistency between the diameters methods and Vol-DWI were determined using Spearman rank correlation, Wilcoxon signed-rank test, and Bland-Altman plots. The OD and MD thresholds indicating infarct size &#x3e;15, 70, and 100 mL were determined by generating receiver-operating characteristic (ROC) curves. Interobserver reliability was established using intraclass correlation coefficient and Bland-Altman plot. <b><i>Results:</i></b> There was a strong positive correlation between the diameters and the Vol-DWI (ABC/2: <i>r</i> = 0.992, OD: <i>r</i> = 0.984, MD: <i>r</i> = 0.970, <i>p</i> &#x3c; 0.001). Infarct volumes measured using the ABC/2 formula were significantly lower than those measured with Vol-DWI (Wilcoxon signed-rank test, <i>z</i> = 6.476, <i>p</i> &#x3c; 0.001). Bland-Altman plot showed that the agreement of the volume &#x3c;70 mL group, and white matter and deep gray nuclei groups was better than that of the other subgroups. For infarct volumes &#x3e;15, 70, and 100 mL, the cutoff value for the MD was identified at 5, 6.9, and 8.4 cm, and the OD was identified at 12.47, 26.4, and 36.4 cm², respectively, with a sensitivity and specificity &#x3e;90%. <b><i>Conclusions:</i></b> The MD method was the best for achieving a rapid and excellent interobserver reliability for estimating infarct volume. Both OD and MD methods can quickly screen patients suitable for recanalization treatment and predict poor prognosis through threshold evaluation.

[Magnetic resonance imaging morphological study of the effects of juvenile febrile convulsions on the brain structure of medial temporal lobe epilepsy]

Objective: To investigate the effect of febrile convulsions on gray matter volume (GMV) in medial temporal lobe epilepsy (mTLE) and its correlation with disease duration. Methods: A retrospective study was conducted to collect 41 mTLE patients with a history of febrile convulsions (mTLE-FC), 42 mTLE patients with no initial precipitating injury (mTLE-noIPI), and 42 normal and age and sex matched normal controls. High-resolution T1-weighted (T(1)WI) whole brain MR scans were performed on all subjects. Voxel-based morphometry were used to obtain GMV brain maps, and the GMV differences between the three groups of subjects were compared (P<0.01, GRF corrected). Finally, Spearmen rank correlation analysis was used to explore the correlation between GMV changes and the course of disease. Results: Compared with the normal control subjects, each mTLE group showed extensive GMV reduction, mainly in the affected hippocampus, thalamus, temporal lobe, and bilateral cerebellum. Further analysis found that mTLE-FC group had more significant reductions in GMV than the mTLE-noIPI group in the affected hippocampus, amygdala, inferior temporal gyrus, contralateral hippocampus, para hippocampus, and inner cingulate gyrus. At the same time, the affected amygdala and hippocampal GMV in the mTLE-FC group was significantly negatively related to the course of disease (r=-0.381, P=0.014), while the mTLE-noIPI group had no downward trend (r=0.081, P=0.611). The atrophic trend of the affected amygdala and hippocampus in patients with mTLE-FC was significantly greater than that in patients with mTLE-noIPI (P=0.029, permutation test). Conclusions: There is extensive damage to the gray matter structure of bilateral cerebral hemispheres, mainly in the hippocampus, in mTLE patients. The brain damage of mTLE patients with a history of juvenile fever convulsions is more extensive and serious, and the trend of progressive exacerbation with the course of the disease is more obvious, suggesting mTLE associated with juvenile fever convulsions may have different pathophysiological mechanisms.

18F-fluorodeoxyglucose positron emission tomography/computed tomography-based radiomic features for prediction of epidermal growth factor receptor mutation status and prognosis in patients with lung adenocarcinoma

Background

To investigate whether radiomic features from (¹⁸F)-fluorodeoxyglucose positron emission tomography/computed tomography [(¹⁸F)-FDG PET/CT] can predict epidermal growth factor receptor (EGFR) mutation status and prognosis in patients with lung adenocarcinoma.

Methods

One hundred and seventy-four consecutive patients with lung adenocarcinoma underwent (¹⁸F)-FDG PET/CT and EGFR gene testing were retrospectively analyzed. Radiomic features combined with clinicopathological factors to construct a random forest (RF) model to identify EGFR mutation status. The mutant/wild-type model was trained on a training group (n=139) and validated in an independent validation group (n=35). The second RF classifier predicting the 19/21 mutation site was also built and evaluated in an EGFR mutation subset (training group, n=80; validation group, n=25). Radiomic score and 5 clinicopathological factors were integrated into a multivariate Cox proportional hazard (CPH) model for predicting overall survival (OS). AUC (the area under the receiver characteristic curve) and C-index were calculated to evaluate the model’s performance.

Results

Of 174 patients, 109 (62.6%) harbored EGFR mutations, 21L858R was the most common mutation type [55.9% (61/109)]. The mutant/wild-type model was identified in the training (AUC, 0.77) and validation (AUC, 0.71) groups. The 19/21 mutation site model had an AUC of 0.82 and 0.73 in the training and validation groups, respectively. The C-index of the CPH model was 0.757. The survival time between targeted therapy and chemotherapy for patients with EGFR mutations was significantly different (P=0.03).

Conclusions

Radiomic features based on (¹⁸F)-FDG PET/CT combined with clinicopathological factors could reflect genetic differences and predict EGFR mutation type and prognosis.

[Radiation dose and image quality of noncontrast chest CT in domestic and imported main stream manufacturers]

Objective: To compare the radiation dose and image quality of noncontrast chest CT and detection of ground-glass opacity pulmonary nodules (GGN) in domestic 128-slice spiral CT with the other CT scanners from three main stream manufacturers. Methods: From May 8, 2018 to October 31, 2018, noncontrast chest CT images from Neusoft 128-slice CT (75 males, 25 females, (42±16) years), dual-source 64-slice CT (53 males, 47 females, (50±16) years) and dual-source 128-slice CT scanners(69 males, 31 females, (62±17) years), Toshiba 128-slice CT (51 males, 49 females, (58±13) years) and GE 128-slice CT scanner (55 males, 45 females, (60±10) years) were collected in Eastern Theater Command and Tianjin People's Hospital. Radiation dose and image quality were evaluated.GGN detected both in Neusoft CT and dual-source CT scanners were used to analyze the displaying ability of lesions. Results: The noise in lung window of Neusoft CT ((37.8±4.9) HU) was higher than that of other mainstream CT scanners, and the noise in mediastinal window ((8.4±1.9) HU) was lower than that of GE 128-slice CT ((9.8±3.2) HU), but higher than that of dual-source CT and Toshiba 128-slice CT ((6.9±3.5)HU) (P<0.05). The absolute value of lung SNR in Neusoft CT was lower than that of other mainstream CT scanners, and the SNR in aorta (4.6±1.3) was lower than those of dual-source CT and Toshiba 128-slice CT(6.8±2.2) (P<0.05), but was not statistically significant compared with GE 128-slice CT (5.0±1.7). The mean CT value of upper lung ((-863±31) HU) at Neusoft CT was higher than 128-row dual-source CT ((-869±35) HU), and the mean CT value of aorta ((37±7) HU) was lower than that of Toshiba 128-slice CT((42±7) HU) and GE 128-slice CT ((45±9) HU) (P<0.05), while the mean CT values of the remaining lung and aorta were not statistically significant (P>0.05). The two readers had good to excellent consistency for image quality in five scanners (the highest kappa value=0.984). The delineation ability of Neusoft CT for GGN boundary was lower than that of dual-source CT (P<0.05), but had similar abilities to display the solid components, lobulation, burring, vacuoles, vascular bundle sign and pleural depression sign of GGN (all P>0.05). Radiation dose of Neusoft CT was lower than Toshiba 128-slice CT, but higher than dual-source 64-sliceCT and GE 128-slice CT scanners (P<0.05). Conclusions: With lower radiation dose than Toshiba 128-slice CT, Neusoft CT chest examination can meet the requirements of clinical diagnosis, but higher radiation dose and the lower image quality than dual-source CT and GE 128-slice CT shown in this study indicate further improvement is needed in terms of software and hardware.

Artificial Intelligence in the Management of Intracranial Aneurysms: Current Status and Future Perspectives

Intracranial aneurysms with subarachnoid hemorrhage lead to high morbidity and mortality. It is of critical importance to detect aneurysms, identify risk factors of rupture, and predict treatment response of aneurysms to guide clinical interventions. Artificial intelligence has received worldwide attention for its impressive performance in image-based tasks. Artificial intelligence serves as an adjunct to physicians in a series of clinical settings, which substantially improves diagnostic accuracy while reducing physicians' workload. Computer-assisted diagnosis systems of aneurysms based on MRA and CTA using deep learning have been evaluated, and excellent performances have been reported. Artificial intelligence has also been used in automated morphologic calculation, rupture risk stratification, and outcomes prediction with the implementation of machine learning methods, which have exhibited incremental value. This review summarizes current advances of artificial intelligence in the management of aneurysms, including detection and prediction. The challenges and future directions of clinical implementations of artificial intelligence are briefly discussed.

Magnetic Resonance Gd-RGD Imaging Study of Hepatocellular Carcinoma with High and Low Metastatic Potential before and after Human Bone Marrow-derived Mesenchymal Stem Cell Intervention

Background:

Biotherapy based on human bone marrow-derived mesenchymal stem cells (BMSCs) is currently the focus of research, especially in the field of autologous stem cell transplantation. A novel type of metastasis-associated magnetic resonance (MR) molecular imaging probe was constructed, and the changes in metastasis and proliferation of hepatocellular carcinoma (HCC) before and after BMSC intervention were observed through MR imaging (MRI).

Methods:

Metastasis-associated MR molecular imaging probe, integrin α_vβ₃ ligand cRGD-PEG-DGL-DTPA-Gd (Gd-RGD), were constructed. After human BMSC intervention was performed for 6 weeks, tumor weight inhibition rates were calculated, and the RGD molecular probe was imaged through MRI with molecular imaging agent Gd-DTPA as control. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the MRI experiment were used as semi-quantitative indicators. Polymerase chain reaction method was performed to detect proliferation- and metastasis-associated indicators, transforming growth factor β-1 (TGFβ1), osteopontin (OPN), and integrin subunit α_v and β₃.

Results:

The highest tumor weight inhibition rates were observed 3 weeks after the BMSC transplantation. The MR Gd-RGD in the HCC tissues after the BMSC intervention showed less enhancement than Gd-DTPA. The Gd-DTPA MRI of control group had higher SNR and CNR than Gd-RGD MRI in the experimental groups (P < 0.05). For high metastatic potential hepatocellular carcinoma (MHCC97-H), significant differences were observed in the SNRs and CNRs of Gd-RGD MRI before and after the BMSC intervention (P < 0.05). For low metastatic potential hepatocellular carcinoma (MHCC97-L), the CNRs of Gd-RGD MRI were statistically different before and after BMSC intervention (P < 0.05). With regard to MHCC97-H, OPN, β₃, and TGFβ1 expression significantly decreased after BMSC intervention (P < 0.05). In MHCC97-L and OPN, β₃, TGFβ1, and α_v expression after BMSC intervention decreased, and the difference was statistically significant (P < 0.05).

Conclusions:

The CNR index of MRI is a good indicator for distinguishing high- and low-metastatic potential HCC tissues. After BMSC transplantation of MRI through the two kinds of tracer, the SNR and CNR indexes can distinguish two kinds of high and low metastatic potential HCC tissues, and Gd-RGD imaging is more suitable in distinguishing the metastatic potential changes through BMSC intervention.

[The altered topology of brain structural network in patients with acute stress response after traffic accident]

Objective: To explore the changes of brain activities in traffic accident survivors with acute stress response (ASR) within a week by using complex networks analysis method based on graph-theory, and to find out the alteration of topological properties in structural brain network. Method: From January, 2013 to February, 2016, twenty traffic accidents survivors with acute stress disorders (Acute Stress Disorder Interview, ASDI>3)and twenty healthy controls underwent the 3T diffusion tensor imaging (DTI) magnetic resonance imaging scan in Nanjing General Hospital.The graph-theory analysis method was used to compare the structural brain network properties and nodal features between ASR survivors and controls.Statistical analyses were also performed by including anxiety and depression as covariates to evaluate their effect.In additional, Pearson correlation was performed between abnormal parametric values and clinical indices. Results: (1) The brain structural networks had small-world properties in both groups; (2) while compared with healthy controls, patients with ASR showed increased weighted connectivity strength (Si, 1.36±0.47 vs 0.92±0.38, P=0.008) and nodal betweenness centrality (BCi, 20±15 vs 7±6, P=0.002) in left triangular part of inferior frontal (IFG triang_L), increased Si in orbital part of inferior frontal gyrus (1.10±0.31 vs 0.77±0.30, P=0.004) and obviously decreased Si in left caudate (0.75±0.24 vs 1.04±0.35, P=0.004); (3) furthermore, the inclusion of anxiety and depression as covariates abolished nodal parameters differences in IFG triang_L, left caudate, thalamus and inferior temporal gyrus. Conclusions: The brain structure network in ASR patients has small world properties.But nodal parameters change obviously in some nodes compared with healthy controls and mainly locate in prefrontal lobe and striatum. High levels of anxiety and depression in ASR patients may partly account for these alterations.

Altered default mode network configuration in posttraumatic stress disorder after earthquake: A resting-stage functional magnetic resonance imaging study

The neural substrates of posttraumatic stress disorder (PTSD) are still not fully elucidated. Hence, this study is to explore topological alterations of the default mode network (DMN) in victims with PTSD after a magnitude of 8.0 earthquake using resting-state functional magnetic resonance imaging (rs-fMRI).This study was approved by the local ethical review board, and all participants signed written informed consent. Sixty-two PTSD victims from the 2008 Sichuan earthquake and 62 matched exposed controls underwent rs-fMRI. PTSD was diagnosed by Clinician-Administered PTSD Scale, and underwent PTSD Checklist-Civilian Version for symptom scoring. The DMN was analyzed by using graph theoretical approaches. Further, Pearson correlation analysis was performed to correlate neuroimaging metrics to neuropsychological scores in victims with PTSD.Victims with PTSD showed decreased DMN functional connectivity strength between the right superior frontal gyrus and left inferior parietal lobule (IPL), and showed increased functional connectivity between the right IPL and precuneus or left posterior cingulate cortex. It was also found that victims with PTSD exhibited decreased nodal efficiency in right superior frontal gyrus and precuneus, and increased nodal efficiency in right hippocampus/parahippocampus. Apart from that, PTSD showed higher nodal degree in bilateral hippocampus/parahippocampus. In addition, the functional connectivity strength between the right IPL and precuneus correlated negatively to the avoid scores (r = -0.26, P = .04).This study implicates alteration of topological features on the DMN in PTSD victims after major earthquake, and provides new insights into DMN malfunction in PTSD based on graph theory.

Comparison of Positron Emission Tomography Using 2-[18F]-fluoro-2-deoxy-D-glucose and 3-deoxy-3-[18F]-fluorothymidine in Lung Cancer Imaging

Background:

The detection of solitary pulmonary nodules (SPNs) that may potentially develop into a malignant lesion is essential for early clinical interventions. However, grading classification based on computed tomography (CT) imaging results remains a significant challenge. The 2-[¹⁸F]-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography (PET)/CT imaging produces both false-positive and false-negative findings for the diagnosis of SPNs. In this study, we compared ¹⁸F-FDG and 3-deoxy-3-[¹⁸F]-fluorothymidine (¹⁸F-FLT) in lung cancer PET/CT imaging.

Methods:

The binding ratios of the two tracers to A549 lung cancer cells were calculated. The mouse lung cancer model was established (n = 12), and micro-PET/CT analysis using the two tracers was performed. Images using the two tracers were collected from 55 lung cancer patients with SPNs. The correlation among the cell-tracer binding ratios, standardized uptake values (SUVs), and Ki-67 proliferation marker expression were investigated.

Results:

The cell-tracer binding ratio for the A549 cells using the ¹⁸F-FDG was greater than the ratio using ¹⁸F-FLT (P < 0.05). The Ki-67 expression showed a significant positive correlation with the ¹⁸F-FLT binding ratio (r = 0.824, P < 0.01). The tumor-to-nontumor uptake ratio of ¹⁸F-FDG imaging in xenografts was higher than that of ¹⁸F-FLT imaging. The diagnostic sensitivity, specificity, and the accuracy of ¹⁸F-FDG for lung cancer were 89%, 67%, and 73%, respectively. Moreover, the diagnostic sensitivity, specificity, and the accuracy of ¹⁸F-FLT for lung cancer were 71%, 79%, and 76%, respectively. There was an obvious positive correlation between the lung cancer Ki-67 expression and the mean maximum SUV of ¹⁸F-FDG and ¹⁸F-FLT (r = 0.658, P < 0.05 and r = 0.724, P < 0.01, respectively).

Conclusions:

The ¹⁸F-FDG uptake ratio is higher than that of ¹⁸F-FLT in A549 cells at the cellular level. ¹⁸F-FLT imaging might be superior for the quantitative diagnosis of lung tumor tissue and could distinguish lung cancer nodules from other SPNs.

[Application of low dose CT angiography with 70 kV in patients with peripheral arterial diseases]

Objective: To assess the image quality, radiation dose and diagnostic efficiency of peripheral arterial CT angiography (CTA) performed at tube voltage of 70 and 120 kV. Methods: Between January 2014 and December 2015, a total of 200 consecutive patients with known or suspected lower extremity arteriosclerosis obliterans (LEASO) underwent CTA.Patients were randomly divided into 2 groups by different scanning protocols.Group A (n=100): 70 kV and 0.8 ml/kg contrast agent, group B (n=100): 120 kV and 100 ml contrast agent.The vessel enhancement, image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of 3 segments were quantified for each protocol.30 patients in group A (420 vessels) and 28 patients in group B (384 vessels) confirmed by DSA.Based on vessel assessments, compared with DSA findings, the diagnostic efficacy of 70 kV and 120 kV protocols for the detection of stenoses over 50% was evaluated.The dose of radiation and contrast agent were recorded.Subjective image quality was evaluated. Results: The subjective image quality of segment crural of group A was significantly higher than that of group B (2.20±0.36 vs 1.72±0.34, P<0.01). The enhancement of 3 segments in group A (500 HU) were significantly higher than these in group B (310 HU) (P<0.05). For the detection of stenoses over 50%, the sensitivity, positive and negative predictive values and accuracy of segment crural in group A (98.6%, 95.8%, 98.1%, 96.7%) were significantly higher than that in group B (90.9%, 88.5%, 91.0%, 89.7%) (P<0.05). Mean DLP for 70-kV protocol was significantly lower than that for 120-kV protocol ( (396±34) vs (1 041±159) mGy·cm, P=0.001). Mean dose of contrast agent and the total amount of iodine for 70-kV protocol were significantly lower than that for 120-kV protocol (53.5 vs 100 ml; 18.7 vs 35 g; P<0.01). Conclusion: CT angiography of peripheral arteries with a low tube voltage of 70 kV and low dose of iodine provides reliable information and serves as a rapidly performed and easily available imaging modality in the diagnosis of LEASO.

[Study of functional connectivity density mapping in patients with acute stress response by using resting-state functional MRI after traffic accident]

Objective: To explore the changes of brain activity in traffic accident survivors with acute stress response within a week by using functional connectivity density (FCD) method. Method: A total of 20 traffic accidents survivors with acute stress disorders (acute stress disorder interview >3) and twenty healthy controls from Nanjing Jinling Hospital underwent the 3.0 T resting-state functional magnetic resonance imaging scan from January 2013 to February 2016. Functional connectivity density mapping was used to compare the brain functional connective networks between acute stress response survivors and controls. In additional, Pearson correlation was performed between abnormal short, long-range FCD values and clinical indices. Results: (1) Compared with controls, patients with acute stress response showed decreased short-range FCD in left ventromedial prefrontal cortex (-0.815±0.264 vs-0.468±0.615, t=-2.198, P<0.05), left hippocampal and parahippocampal gyri (-1.212±0.135 vs-0.887±0.234), t=-5.070, all P<0.05), and increased short-range FCD in right precentral gyrus(0.428±0.256 vs 0.016±0.298, t=4.456, P<0.05), left inferior parietal and superior parietal lobes (0.623±0.290 vs 0.143±0.300, t=4.878, allP<0.05); (2)compared with normal controls, ASR patients showed increased long-range FCD in left precuneus (0.502±0.400 vs-0.042±0.253, t=4.879, P<0.05); (3)the HAMA score of patients positively correlated with short-range FCD value of the left vmPFC (r=0.50, P<0.05). Conclusion: The long-and short-range functional connectivity in frontal-limbic system is widely changed in survivors with acute stress response, especially the short-range FCD change more significantly, and partly correlated with the severity of their stress symptoms.

Cerebral CTA with Low Tube Voltage and Low Contrast Material Volume for Detection of Intracranial Aneurysms

BACKGROUND AND PURPOSE

Multidetector row CTA has become the primary imaging technique for detecting intracranial aneurysms. Technical progress enables the use of cerebral CTA with lower radiation doses and contrast media. We evaluated the diagnostic accuracy of 80-kV(peak) cerebral CTA with 30 mL of contrast agent for detecting intracranial aneurysms.

MATERIALS AND METHODS

Two hundred four patients were randomly divided into 2 groups. Patients in group A (n = 102) underwent 80-kVp CTA with 30 mL of contrast agent, while patients in group B (n = 102) underwent conventional CTA (120 kVp, 60 mL of contrast agent). All patients underwent DSA. Image quality, diagnostic accuracy, and radiation dose between the 2 groups were compared.

RESULTS

Diagnostic image quality was obtained in 100 and 99 patients in groups A and B, respectively (P = .65). With DSA as reference standard, diagnostic accuracy on a per-aneurysm basis was 89.9% for group A and 93.9% for group B. For evaluating smaller aneurysms (<3 mm), the diagnostic accuracy of groups A and B was 86.3% and 90.8%, respectively. There was no difference in diagnostic accuracy between each CTA group and DSA (all, P > .05) or between the 2 CTA groups (all, P > .05). The effective dose in group A was reduced by 72.7% compared with group B.

CONCLUSIONS

In detecting intracranial aneurysms with substantial radiation dose and contrast agent reduction, 80-kVp/30-mL contrast CTA provides the same diagnostic accuracy as conventional CTA.

Reproducibility of image-based computational models of intracranial aneurysm: a comparison between 3D rotational angiography, CT angiography and MR angiography

BACKGROUND

Reconstruction of patient-specific biomechanical model of intracranial aneurysm has been based on different imaging modalities. However, different imaging techniques may influence the model geometry and the computational fluid dynamics (CFD) simulation. The aim of this study is to evaluate the differences of the morphological and hemodynamic parameters in the computational models reconstructed from computed tomography angiography (CTA), magnetic resonance angiography (MRA) and 3D rotational angiography (3DRA).

METHODS

Ten patients with cerebral aneurysms were enrolled in the study. MRA, CTA and 3DRA were performed on all patients. For each patient, three patient-specific models were reconstructed respectively based on the three sets of imaging data of the patient. CFD simulations were performed on each model. Model geometry and hemodynamic parameters were compared between the three models.

RESULTS

In terms of morphological parameters, by comparing CTA based models (CM) and 3DRA based models (DM) which were treated as the "standard models", the aspect ratio had the minimum difference (Δ = 8.3 ± 1.72 %, P = 0.953) and the surface distance was 0.25 ± 0.07 mm. Meanwhile, by comparing MRA based models (MM) and DM, the size had the minimum difference (Δ = 6.6 ± 1.85 %, P = 0.683) and the surface distance was 0.36 ± 0.1 mm. In respect of hemodynamic parameters, all three models showed a similar distribution: low average WSS at the sack, high OSI at the body and high average WSSG at the neck. However, there was a large variation in the average WSS (Δ = 34 ± 5.13 % for CM, Δ = 40.6 ± 9.21 % for MM).

CONCLUSION

CTA and MRA have no significant differences in reproducing intracranial aneurysm geometry. The CFD results suggests there might be some significant differences in hemodynamic parameters between the three imaging-based models and this needs to be considered when interpreting the CFD results of different imaging-based models. If we only need to study the main flow patterns, three types of image-based model might be all suitable for patient-specific computational modeling studies.

Abnormal Amygdala Resting-State Functional Connectivity in Irritable Bowel Syndrome

BACKGROUND AND PURPOSE

Functional neuroimaging studies in irritable bowel syndrome have revealed abnormalities in the corticolimbic regions, specifically, hyperactivity of the amygdala during visceral and somatic stimulation. This study investigated changes in the neural circuitry of the amygdala in patients with irritable bowel syndrome based on resting-state functional connectivity.

MATERIALS AND METHODS

Functional MR imaging data were acquired from 31 patients with irritable bowel syndrome and 32 healthy controls (matched for age, sex, and educational level) during rest, and the resting-state functional connectivity of bilateral amygdalae was compared. Multiple regression was performed to investigate the relationship between clinical indices of patients with irritable bowel syndrome and resting-state functional connectivity.

RESULTS

Compared with healthy controls, patients with irritable bowel syndrome had higher positive resting-state functional connectivity between the amygdala and insula, midbrain, parahippocampal gyrus, pre- and postcentral gyri, and supplementary motor area. The inclusion of anxiety and depression as covariates did not alter amygdala resting-state functional connectivity differences between the study groups. Multiple covariate regression results showed that the pain intensity in patients with irritable bowel syndrome positively correlated with resting-state functional connectivity between the amygdala and supplementary motor area, pre- and postcentral gyri, and insula, while the Irritable Bowel Syndrome-Symptom Severity Score positively correlated with resting-state functional connectivity between the amygdala and insula and midbrain.

CONCLUSIONS

Patients with irritable bowel syndrome showed disturbed amygdala resting-state functional connectivity with the corticolimbic regions, which could partly account for the enhanced emotional arousal and visceral information processing associated with irritable bowel syndrome.

Putting age-related task activation into large-scale brain networks: A meta-analysis of 114 fMRI studies on healthy aging

Normal aging is associated with cognitive decline and underlying brain dysfunction. Previous studies concentrated less on brain network changes at a systems level. Our goal was to examine these age-related changes of fMRI-derived activation with a common network parcellation of the human brain function, offering a systems-neuroscience perspective of healthy aging. We conducted a series of meta-analyses on a total of 114 studies that included 2035 older adults and 1845 young adults. Voxels showing significant age-related changes in activation were then overlaid onto seven commonly referenced neuronal networks. Older adults present moderate cognitive decline in behavioral performance during fMRI scanning, and hypo-activate the visual network and hyper-activate both the frontoparietal control and default mode networks. The degree of increased activation in frontoparietal network was associated with behavioral performance in older adults. Age-related changes in activation present different network patterns across cognitive domains. The systems neuroscience approach used here may be useful for elucidating the underlying network mechanisms of various brain plasticity processes during healthy aging.

Decrease with aging of the microcirculatory function of the lumbar vertebral marrow preceding the loss of bone material density and the onset of intervertebral discal degeneration: A study about the potential cause

Objective

Using a dynamic computed tomographic perfusion (CTP) imaging method to explore the age-related distribution of the microcirculation perfusion function in the vertebral marrow, the bone material density (BMD), and the intervertebral discal degeneration (IDD). Further, to discuss a possible causation relationship between them.

Methods

One hundred and eighty-six people were randomly enrolled by stratified sampling and grouped by age: ≤15, 16–25, 26–35, 36–45, 46–55, 56–65, 66–75, and ≥76 years old. The average CTP and BMD of the third and fourth lumbar vertebrae marrow were measured and the IDD incidence of the third-fourth vertebrae was assessed. The temporal–spatial distribution patterns of the age-related changes of the CTP, BMD, and IDD were described, and the correlations between them were calculated.

Results

The microcirculatory perfusion function of the vertebral marrow develops to maturity by 25 years and is maintained until age 35, then declines with aging. The BMD grew to a peak from 26 to 45 years old, then decreased yearly. The IDD showed a sudden increase after 45 years of age. The CTP [BF (r = 0.806, P = 0.000), BV (r = 0.685, P = 0.005) and PMB (r = 0.619, P = 0.001)] showed strong positive correlations and CTP [TTP (r = −0.211, P = 0.322) and MTT (r = −0.598, P = 0.002)] showed negative correlations with BMD. The CTP [BF (r = −0.815, P = 0.000), BV (r = −0.753, P = 0.000) and PMB (r = −0.690, P = 0.000)] had strong negative correlations, and CTP [TTP (r = 0.323, P = 0.126) and MTT (r = 0.628, P = 0.001)] had positive correlations with the incidence of IDD.

Conclusion

The decrease with aging of the microcirculatory perfusion in the lumbar vertebral marrow preceded, and is a potential causative factor for the loss of BMD and the onset of IDD.

Imaging observations of pulmonary inflammatory myofibroblastic tumors in patients over 40 years old

Pulmonary inflammatory myofibroblastic tumors (PIMTs) are extremely rare in adults. If occurring in patients >40 years old, PIMT should be rapidly distinguished from lung cancer. The present study aimed to characterize the imaging features of PIMT in patients >40 years old in order to improve the diagnosis of PIMT. The imaging data of 10 patients with PIMT were reviewed retrospectively. Of the patients, eight underwent computed tomography (CT), two underwent positron emission tomography (PET)/CT and four underwent single-photon emission computed tomography (SPECT). Unenhanced CT revealed 10 lesions with a maximum diameter ranging between 5 and 57 mm located in the lower (n=6) or upper (n=4) lobe, in a peripheral (n=9) or central (n=1) region, and that were well- (n=4) or ill-defined (n=6), and round to oval (n=5) or irregular (n=5) in shape. Calcification (n=3), necrosis (n=6), cavity (n=4), air bronchogram (n=6) and obstructive pneumonia (n=1) were also observed in the patients. Contrast-enhanced CT revealed six lesions with moderate to high contrast enhancement in the arterial and venous phases, including four lesions with delayed enhancement. PET/CT identified two lesions with increased tracer uptake that were homogeneous and heterogeneous and each exhibited a maximal standard uptake value (SUV_max) of 6.0 and 5.4, respectively. The delayed PET/CT revealed foci that each exhibited an increased SUV_max of 6.9 and 5.9, respectively. SPECT demonstrated no definitive bone metastases, but did reveal atypical hypertrophic pulmonary osteoarthropathy in one patient. The combined imaging methods may lead to a more precise evaluation of PIMT in patients >40 years old.

Reduction of prohibitin expression contributes to left ventricular hypertrophy via enhancement of mitochondrial reactive oxygen species formation in spontaneous hypertensive rats

Left ventricular hypertrophy (LVH) in hypertension is characterized by thickening of myocardium and decrease in heart chamber volume in response to mechanical or pathological stress, but the underlying molecular mechanisms remain to be defined. In this work, we investigate whether mitochondrial prohibitin (PHB) was involved in the progression of LVH in spontaneous hypertensive rats (SHR). First, it was found that mitochondrial dysfunction occurred in left ventricles of SHR. Through analysis using quantitative reverse transcription polymerase chain reaction and Western blotting, it was found that PHB mRNA and mitochondrial PHB levels in left ventricles of SHR were significantly lower than that in Wistar-Kyoto rats. Furthermore, PHB mRNA levels were negatively correlated to left ventricles weight-to-body weight ratio in SHR. Knockdown of PHB led to increased formation of mitochondrial reactive oxygen species (ROS) and reduced activities of complex I, mitochondrial adenosine triphosphate generation and mitochondrial membrane potential in cultured cardiomyocytes. Knockdown of PHB contributed to the cardiomyocyte hypertrophy, which could be attenuated by treatment with the Tempol. Angiotensin II (AngII) was increased in plasma and left ventricles of SHR. Incubation with AngII reduced mitochondrial PHB expression in cardiomyocytes, which was reversed when pretreated with losartan. In conclusion, reduction of PHB expression in left ventricles in SHR contributed to LVH, at least in part, through promoting mitochondrial ROS formation.

Targeted fluorescent magnetic nanoparticles for imaging of human breast cancer

Magnetic nanoclusters coated with ruthenium (II) complexes doped with silica (fluorescent magnetic nanoparticles or FMNPs) could be used for magnetic resonance imaging (MRI) and optical imaging (OI) of human breast cancer. To achieve the targeting imaging of tumors, the peptide cyclic-arginine-glycine-aspartic acid (RGD) was chosen as the probe for specific targeting integrin αvβ3 over expressed in human breast cancer MDA-MB-231 cells. The cytotoxicity tests in vitro showed little toxicity of the synthesized RGD-FMNPs with the size of 150 nm. The in vivo study also showed no obvious acute toxicity after the injection of RGD-FMNPs in mice bearing MDA-MB-231 tumors. After 24 hours of co-culture with MDA-MB-231 cells, the cellular uptake of RGD-FMNPs significantly increased compared to that of FMNPs. T2-weighted (T2W) MRI demonstrated a negative enhancement in mice injected with RGD-FMNPs approximately three times of that injected with FMNPs (12.867 ± 0.451 ms vs. 4.833 ± 0.513 ms, P < 0.05). The Prussian blue staining results confirmed more RGD-FMNPs accumulated around the tumors than FMNPs. These results demonstrated the potential application of RGD-FMNPs as a targeting molecular probe for detection of breast cancer using MRI and OI. The synthesized RGD-FMNPs could be potentially used for biomedical imaging in the future.

Multimodality magnetic resonance imaging in hepatic encephalopathy: An update

Hepatic encephalopathy (HE) is a neuropsychiatric complication of cirrhosis or acute liver failure. Currently, HE is regarded as a continuous cognitive impairment ranging from the mildest stage, minimal HE to overt HE. Hyperammonaemia and neuroinflammation are two main underlying factors which contribute to the neurological alterations in HE. Both structural and functional impairments are found in the white mater and grey mater involved in HE. Although the investigations into HE pathophysiological mechanism are enormous, the exact pathophysiological causes underlying HE remain controversial. Multimodality magnetic resonance imaging (MRI) plays an important role in helping to understand the pathological process of HE. This paper reviews the up-to-date multimodality MRI methods and predominant findings in HE patients with a highlight of the increasingly important role of blood oxygen level dependent functional MRI.

18F-fluorodeoxyglucose positron emission tomography/computed tomography findings of gastric lymphoma: Comparisons with gastric cancer

The role of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in numerous malignant tumors, including gastric lymphoma, is well-established. However, there have been few studies with regard to the ¹⁸F-FDG PET/CT features of gastric lymphoma. The aim of the present study was to characterize the ¹⁸F-FDG PET/CT features of gastric lymphoma, which were compared with those of gastric cancer. Prior to treatment, ¹⁸F-FDG PET/CT was performed on 24 patients with gastric lymphoma and 43 patients with gastric cancer. The ¹⁸F-FDG PET/CT pattern of gastric wall lesions was classified as one of three types: Type I, diffuse thickening of the gastric wall with increased FDG uptake infiltrating more than one-third of the total stomach; type II, segmental thickening of the gastric wall with elevated FDG uptake involving less than one-third of the total stomach; and type III, local thickening of the gastric wall with focal FDG uptake. The incidence of the involvement of more than one region of the stomach was higher in the patients with gastric lymphoma than in those with gastric cancer. Gastric FDG uptake was demonstrated in 23 of the 24 patients (95.8%) with gastric lymphoma and in 40 of the 43 patients (93.0%) with gastric cancer. Gastric lymphoma predominantly presented with type I and II lesions, whereas gastric cancer mainly presented with type II and III lesions. The maximal thickness was larger and the maximal standard uptake value (SUV_max) was higher in the patients with gastric lymphoma compared with those with gastric cancer. A positive correlation between the maximal thickness and SUV_max was confirmed for the gastric cancer lesions, but not for the gastric lymphoma lesions. There was no difference in the maximal thickness and SUV_max of the gastric wall lesions between the patients without and with extragastric involvement, for gastric lymphoma and gastric cancer. Overall, certain differences exist in the findings between gastric lymphoma and gastric cancer patients on ¹⁸F-FDG PET/CT images, which may contribute to the identification of gastric lymphoma.

Lung ischaemia-reperfusion injury in a canine model: dual-energy CT findings with pathophysiological correlation

OBJECTIVE

To evaluate dual-energy CT (DECT) findings of pulmonary ischaemic-reperfusion injury (PIRI) and its pathophysiological correlation in the canine model.

METHODS

A PIRI model was established in 11 canines, utilizing closed pectoral balloon occlusion. Two control canines were also included. For the PIRI model, the left pulmonary artery was occluded with a balloon, which was deflated and removed after 2 h. DECT was performed before, during occlusion and at 2, 3 and 4 h thereafter and was utilized to construct pulmonary perfusion maps. Immediately after the CT scan at the fourth hour post reperfusion, the canines were sacrificed, and lung specimens were harvested for pathological analysis. CT findings, pulmonary artery pressure and blood gas results were then analysed.

RESULTS

Data at every time point were available for 10 animals (experimental group, n = 8; control group, n = 2). Quantitative measurements from DECT pulmonary perfusion maps found iodine attenuation values of the left lung to be the lowest at 2 h post embolization and the highest at 1 h post reperfusion. In the contralateral lung, perfusion values also peaked at 1 h post reperfusion. Continuous hypoxia and acid-based disorders were observed during PIRI, and comprehensive analysis showed physiological changes to be worst at 3 h post reperfusion.

CONCLUSION

DECT pulmonary perfusion mapping demonstrated pulmonary perfusion of the bilateral lungs to be the greatest at 1 h post reperfusion. These CT findings corresponded with pathophysiological changes.

ADVANCES IN KNOWLEDGE

DECT pulmonary perfusion mapping can be used to evaluate lung ischaemia-reperfusion injury.

Collecting duct carcinoma of the kidney: Imaging observations of a rare tumor

Collecting duct carcinoma (CDC) is a rare type of renal neoplasm. Early diagnosis is possibly the only factor leading to a prolonged survival for patients with CDC. The purpose of the present study was to characterize the imaging features of CDC and improve its diagnosis. Radiological data of six patients were retrospectively reviewed by three experienced radiologists, including six cases examined with non-contrast computed tomography (CT) scans, five with contrast-enhanced CT scans, one with magnetic resonance urography, one with renal dynamic imaging and two with conventional whole-body ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scans. All patients were pathologically confirmed with CDC. In total, seven tumors were detected in the six cases, with a mean size of 5.3 cm. Of the tumors, two were solid and the rest were complex solid and cystic. In addition, six tumors were located in medullary areas and only one tumor was found in the cortical location. Cystic components were observed in five tumors. Weak enhancements were observed in all six tumors examined with contrast-enhanced CT, and heterogeneous enhancements were also observed in the majority of these tumors with the exception of one tumor. Infiltrative growth and expansible growth were found in five and two tumors, respectively. Metastatic lesions were detected in all six patients. On MR urography, the involved kidney exhibited similar imaging observations to the CT scan. Renal dynamic imaging revealed a decreased renal function in the involved kidney and an increased renal function in the contralateral kidney. On PET/CT imaging, a marked uptake of ¹⁸F-FDG was found in primary and metastatic lesions. The results of the present study indicated that medullary location, weak and heterogeneous enhancement, infiltrative growth, damage of renal function in the involved kidney and a marked uptake of ¹⁸F-FDG are imaging observations commonly identified in patients with CDC. When a renal tumor exhibits these imaging features, CDC may be suggested as a valuable differential diagnosis.

Takayasu arteritis: imaging spectrum at multidetector CT angiography

Takayasu arteritis is a chronic, idiopathic, inflammatory disease that primarily affects large vessels, such as the aorta and its major branches and the pulmonary and coronary arteries. The non-specific inflammation of involved vessels usually leads to concentric wall thickening, fibrosis and thrombus formation. Diseased arteries become stenotic or occluded, undergo vascular remodelling or develop aneurysms. According to the involvement of arteries, six types of Takayasu arteritis are documented. The purpose of this pictorial review is to illustrate the various multidetector CT angiography appearances of Takayasu arteritis and to discuss the differential diagnosis.

[Mesoporous silica nanoparticles for cancer theranostic drug delivery]

Mesoporous silica nanoparticles as drug carrier have become the new hot point in the field of biomedical application in recent years. This review focuses on the more recent developments and achievements on experimental design aspect of mesoporous silica nanoparticles with cancer diagnosis and therapy. The key advances of functionalization strategies of mesoporous silica nanoparticles with controlled release, tumor targeting and overcoming multidrug resistance are discussed in particular. Mesoporous silica nanoparticles as unique delivery systems have the potential to provide significantly a sound platform for cancer theranostic application.

128-slice Dual-source Computed Tomography Coronary Angiography in Patients with Atrial Fibrillation: Image Quality and Radiation Dose of Prospectively Electrocardiogram-triggered Sequential Scan Compared with Retrospectively Electrocardiogram-gated Spiral Scan

Objective To evaluate the image quality (IQ) and radiation dose of 128-slice dual-source computed tomography (DSCT) coronary angiography using prospectively electrocardiogram (ECG)-triggered sequential scan mode compared with ECG-gated spiral scan mode in a population with atrial fibrillation. Methods Thirty-two patients with suspected coronary artery disease and permanent atrial fibrillation referred for a second-generation 128-slice DSCT coronary angiography were included in the prospective study. Of them, 17 patients (sequential group) were randomly selected to use a prospectively ECG-triggered sequential scan, while the other 15 patients (spiral group) used a retrospectively ECG-gated spiral scan. The IQ was assessed by two readers independently, using a four-point grading scale from excel-lent (grade 1) to non-assessable (grade 4), based on the American Heart Association 15-segment model. IQ of each segment and effective dose of each patient were compared between the two groups. Results The mean heart rate (HR) of the sequential group was 96±27 beats per minute (bpm) with a variation range of 73±25 bpm, while the mean HR of the spiral group was 86±22 bpm with a variationrange of 65±24 bpm. Both of the mean HR (t=1.91, P=0.243) and HR variation range (t=0.950, P=0.350) had no significant difference between the two groups. In per-segment analysis, IQ of the sequential group vs. spiral group was rated as excellent (grade 1) in 190/244 (78%) vs. 177/217 (82%) by reader1 and 197/245 (80%) vs. 174/214 (81%) by reader2, as non-assessable (grade 4) in 4/244 (2%) vs. 2/217 (1%) by reader1 and 6/245 (2%) vs. 4/214 (2%) by reader2. Overall averaged IQ per-patient in the sequential and spiral group showed equally good (1.27±0.19 vs. 1.25±0.22, Z=-0.834, P=0.404). The effective radiation dose of the sequential group reduced significantly compared with the spiral group (4.88±1.77 mSv vs. 10.20±3.64 mSv; t=-5.372, P=0.000). Conclusion Compared with retrospectively ECG-gated spiral scan, prospectively ECG-triggered sequential DSCT coronary angiography provides similarly diagnostically valuable images in patients with atrial fibrillation and significantly reduces radiation dose.

Impact of low versus conventional doses of chemotherapy during transcatheter arterial chemo-embolization on serum fibrosis indicators and survival of liver cancer patients

OBJECTIVES

To explore the impact of low- vs conventional-dose chemotherapy via transcatheter arterial chemo-embolization (TACE) on serum fibrosis indicators and treatment efficacy of hepatocellular cancer patients (HCC).

MATERIALS AND METHODS

Patients fulfilling the eligibility criteria were assigned to TACE in Group A (with low-dose chemotherapy) or Group B (conventional-dose chemotherapy). Four serum fibrosis related indicators, hyaluronic acid(HA), human pro-collagen type-III (hPC-III), laminin (LN), and collagen type-IV(IV-C) before TACE were compared with the values 7 days after TACE. The response rate and survival time were also compared between the two groups.

RESULTS

Fifty patients with HCC were enrolled in this study, including 25 in Group A and 25 in Group B. No significant differences were detected between the two groups in the four indicators before TACE. After TACE, the value of the four serum indicators increased significantly in Group B. However, no significant differences regarding these four indicators were found in Group A after TACE. Significant differences were demonstrated between the two groups after TACE, but median survival time and 1 or 2 year overall survival rates did not differ (P>0.05).

CONCLUSIONS

Low-, compared with conventional-dose chemotherapy exerts the same impact on the variation of fibrosis related indicators and has no influence on median survival time and survival rate after TACE in HCC patients.

Multimodality MR imaging findings of low-grade brain edema in hepatic encephalopathy

HE is a neuropsychiatric syndrome that develops in patients with severe liver diseases, with portosystemic shunt surgery in the form of diffuse mild brain edema. It is also associated with functional changes, such as those in attention and the DMN. MR imaging offers a range of capabilities for assessing the low-grade brain edema and its functional changes in brain affected by HE; therefore, it provides the opportunity to uncover the pathophysiologic mechanisms of HE. This article will review our current understanding of the pathophysiology of low-grade brain edema and will outline the role of structural MR imaging, MTR, DWI, DTI, and MR spectroscopy in the detection of low-grade brain edema, and the role of BOLD fMRI in the exploration of the related functional changes. A perspective of the study in this area will also be provided.