Electric vehicle wireless power transfer brings additional electromagnetic exposure (EME) risks to the human body, especially those with metal implants. This paper focuses on the safety assessment of human EME with aortic valve stents (AVS), and establishes electromagnetic simulation models for different genders of humans, AVS, and electric vehicle-wireless power transfer (EV-WPT) systems. The transmission power of the EV-WPT system is 11 kW. Considering the uncertainty of the EV-WPT system and AVS in practical use, an efficient deep neural network method is proposed to evaluate the EME safety to different genders of humans. Using the standard limits of the International Committee on Non-Ionizing Radiation Protection (ICNIRP) as the judgment standard, comparing human EME under static conditions, it is demonstrated that AVS can change the distribution of induced electric fields in the human body and increase the risk of human EME. Moreover, the probability of male human EME exceeding the standard limits is 22.78% higher than that of female human.
Aims: To explore the effect of coronary calcification severity on the measurements and diagnostic performance of computed tomography-derived fractional flow reserve (FFR; CT-FFR). Methods: This study included 305 patients (348 target vessels) with evaluable coronary calcification (CAC) scores from CT-FFR CHINA clinical trial. The enrolled patients all received coronary CT angiography (CCTA), CT-FFR, and invasive FFR examinations within 7 days. On both per-patient and per-vessel levels, the measured values, accuracy, and diagnostic performance of CT-FFR in identifying hemodynamically significant lesions were analyzed in all CAC score groups (CAC = 0, > 0 to <100, ≥ 100 to <400, and ≥ 400), with FFR as reference standard. Results: In total, the sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under receiver operating characteristics curve (AUC) of CT-FFR were 85.8, 88.7, 86.9, 87.8, 87.1%, 0.90 on a per-patient level and 88.3, 89.3, 89.5, 88.2, 88.9%, 0.88 on a per-vessel level, respectively. Absolute difference of CT-FFR and FFR values tended to elevate with increased CAC scores (CAC = 0: 0.09 ± 0.10; CAC > 0 to <100: 0.06 ± 0.06; CAC ≥ 100 to <400: 0.09 ± 0.10; CAC ≥ 400: 0.11 ± 0.13; p = 0.246). However, no statistically significant difference was found in patient-based and vessel-based diagnostic performance of CT-FFR among all CAC score groups. Conclusion: This prospective multicenter trial supported CT-FFR as a viable tool in assessing coronary calcified lesions. Although large deviation of CT-FFR has a tendency to correlate with severe calcification, coronary calcification has no significant influence on CT-FFR diagnostic performance using the widely-recognized cut-off value of 0.8.
Background and Purpose- We aimed to systematically investigate the characteristics of cervicocranial artery dissection (CCAD) on high-resolution magnetic resonance imaging that are associated with acute ischemic stroke. Methods- Patients with CCAD were recruited and divided into stroke and nonstroke groups. The lesion location, the presence of a double lumen, intimal flap, intramural hematoma, pseudoaneurysm, irregular surface, intraluminal thrombus, and other quantitative parameters of each dissected segment were reviewed. Multiple logistic regression was used to examine the association between imaging features of CCAD and ischemic stroke. Results- A total of 145 affected vessels from 118 patients with CCAD were analyzed. Anterior circulation, intramural hematoma, irregular surface, intraluminal thrombus, and severe stenosis (>70%) on high-resolution magnetic resonance imaging were more prevalent in CCAD patient with stroke (54.4% versus 36.4%; P=0.030, 96.2% versus 84.8%; P=0.017, 74.7% versus 37.9%; P<0.001, 44.3% versus 4.5%; P<0.001, and 54.4% versus 31.8%; P=0.008, respectively). In multivariable logistic regression analysis, the presence of irregular surface and intraluminal thrombus on imaging were independently associated with acute ischemic stroke in CCAD with odds ratios of 4.29 (95% CI, 1.61-11.46, P=0.004) and 7.48 (95% CI, 1.64-34.07, P=0.009). Conclusions- The current findings supported that the presence of irregular surface and intraluminal thrombus were related to stroke occurrence in patients with CCAD. High-resolution magnetic resonance imaging might give insights into pathogenesis of ischemic stroke in CCAD. It may be useful for individual prediction of ischemic stroke early in CCAD.
Abstract Background Blood-brain barrier (BBB) breakdown, as an early biomarker for vascular mild cognitive impairment (vMCI), has only been validated by a few studies. The aim of this study was to investigate whether compromised BBB integrity is involved in vMCI patients, and detect the relationship between BBB breakdown and cognitive function. BBB leakage in vMCI was explored, and the relationship between BBB leakage and cognitive function was discussed in this study. Methods This is a cross-sectional study involving 26 vMCI patients and 21 sex- and age-matched healthy controls. Dynamic contrast-enhanced-magnetic resonance imaging was performed for all participants, to determine BBB leakage. Leakage volume, leakage rate, and fractional blood plasma volume (Vp) in the grey and white matter were evaluated. Neuropsychological tests were used to determine cognitive function. Leakage rate, leakage volume, and Vp in different brain locations, including deep grey matter, cortical grey matter, white matter hyperintensity, and normal-appearing white matter were compared between the two groups. Results Multivariable linear regression analyses revealed that in all regions of interest, the leakage rate was significantly higher in vMCI patients relative to controls. Leakage volume in normal-appearing white matter and white matter hyperintensity were significantly higher, while Vp in normal-appearing white matter, deep grey matter, and cortical grey matter were significantly lower in vMCI patients. Moreover, Montreal Cognitive Assessment scores decreased with the increase of leakage rate in white matter hyperintensity. Conclusion Increased BBB permeability was detected in vMCI patients and was related to cognitive decline, which suggested that BBB breakdown might be involved in cognitive dysfunction pathogenesis.
Current magnetic resonance imaging (MRI) of pancreatic disease is qualitative in nature. Quantitative imaging offers several advantages, including increased reproducibility and sensitivity to detect mild or diffuse disease. The role of multiparametric mapping MRI in characterizing various tissue types in pancreatic disease such as chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) has rarely been evaluated.To evaluate the feasibility of multiparametric mapping [T1, T2, and apparent diffusion coefficient (ADC)] in defining tissue characteristics that occur in CP and PDAC to improve disease diagnosis.Pancreatic MRI was performed in 17 patients with PDAC undergoing therapy, 7 patients with CP, and 29 healthy volunteers with no pancreatic disease. T1 modified Look-Locker Inversion Recovery (T1 MOLLI), T2-prepared gradient-echo, and multi-slice single-shot echo-planar diffusion weighted imaging (SS-EPI DWI) sequences were used for data acquisition. Regions of interest (ROIs) of pancreas in PDAC, CP, and control subjects were outlined by an experienced radiologist. One-way analysis of variance (ANOVA) was used to compare the difference between groups and regions of the pancreas, and Tukey tests were used for multiple comparison testing within groups. Receiver operator characteristic (ROC) curves were analyzed, and the areas under the curves (AUCs) were calculated using single parameter and combined parameters, respectively.T1, T2, and ADC values of the entire pancreas among PDAC, CP, and control subjects; and between upstream and downstream portions of the pancreas in PDAC patients were all significantly different (p < 0.05). The AUC values were 0.90 for T1, 0.55 for T2, and 0.71 for ADC for independent prediction of PDAC. By combining T1, T2, and ADC, the AUC value was 0.94 (sensitivity 91.54%, specificity 85.81%, 95% CI: 0.92-0.96), which yielded higher accuracy than any one parameter only (p < 0.001).Multiparametric mapping MRI is feasible for the evaluation of the differences between PDAC, CP, and normal pancreas tissues. The combination of multiple parameters of T1, T2, and ADC provides a higher accuracy than any single parameter alone in tissue characterization of the pancreas.
Several studies have demonstrated that compromised blood-brain barrier (BBB) integrity may play a pivotal role in the pathogenesis of individual cerebral small vessel disease (cSVD) markers, but the association between BBB permeability and total magnetic resonance imaging (MRI) cSVD burden remains unclear. This study aimed to investigate the relationship between BBB permeability and total MRI cSVD burden.Consecutive participants without symptomatic stroke history presented for physical examination were enrolled in this cross-sectional study. The presence of lacunes, white matter hyperintensities (WMH), cerebral microbleeds, and enlarged perivascular spaces was recorded in an ordinal score (range 0-4). We used dynamic contrast-enhanced-MRI and Patlak pharmacokinetic model to quantify BBB permeability in the normal-appearing white matter (NAWM), WMH, cortical gray matter (CGM), and deep gray matter (DGM).All 99 participants averaged 70.33 years old (49-90 years). Multivariable linear regression analyses adjusted for age, sex, and vascular risk factors showed that leakage rate and area under the leakage curve in the NAWM, WMH, CGM, and DGM were positively associated with total MRI cSVD burden (all P < 0.01). Moreover, fractional blood plasma volumes in the NAWM, CGM, and DGM were negatively associated with total MRI cSVD burden (all P < 0.05).This study verified that compromised BBB integrity is associated with total MRI cSVD burden, suggesting that BBB dysfunction may be a critical contributor to the pathogenesis of cSVD. Longitudinal studies are required to determine whether there is a causal relationship between BBB permeability and total MRI cSVD burden.
Objective
Dynamic MRI with rectum injectionis employed to assess female spastic pelvic floor syndrome of anorectal morphology and function in relation to various pelvic compartment abnormalitiesin female outlet obstruction constipation.
Methods
Dynamic MRI was performed in 53 female patients (14-78 years of age, with a mean age of 52.7±15.8 years) with clinical diagnosis of spastic pelvic floor syndrome.The homemade highly conformable sacculus was inserted into the rectum to simulate stool. The relevant measurements were then obtained during straining before and after rectum injection.
Results
Among the 53 female patients with spastic pelvic floor syndrome, 24 patients (45.3%) have multifocal disorders involving more than one compartment.The difference in the anorectal angles before and after rectum injection was not significant (χ2=0.603, P>0.05) . Differences in the cystocele, vaginal or cervical prolapse, rectocele, and descending perineum before and after rectum injection were significant.
Conclusion
Using dynamic MRI with rectum injection allows for the accurate evaluation of the anorectal morphology and function related to various pelvic compartment abnormalitiesin female spastic pelvic floor syndrome; thus, this method is proved valuable in the diagnosis and treatment of female spastic pelvic floor syndrome.
Key words:
Pelvic floor; Magnetic resonance imaging; Spastic pelvic floor syndrome
To explore the diagnostic value of 3.0T MRI in neurogenic tumor of soft tissue in the extremities.The MRI appearance of 17 neurogenic tumors with pathological confirmation was retrospectively analyzed. Various imaging characteristics of tumors were evaluated and different imaging findings were compared. The diagnosis value of each MRI features was evaluated with receiver-operating-characteristics (ROC) analysis.In the benign tumors significant differences between neurilemmoma and neurofibromas were noted for the position (P = 0.044). Heterogenicity on T(2)-weighted fat suppression images was also significant in differentiating between neurilemmoma and neurofibromas ( P = 0.020) . The shape of tumors, maximum length of tumor short diameter, edem around masses, relationship with adjoining fascia had the best discriminatory ability. The ROC analysis yield the area under curve (AUC) of them was 0.967 (P = 0.037), 0.923 (P = 0.048) , 0.981 (P = 0.034) , 0.981 (P = 0.034), respectively.If the neurogenic tumors of soft tissue in the extremities had one or several features of these characteristics (irregular margin, big volume, edem around masses, aggressive behavior with adjoining fascia) on 3.0T MRI, they had more possibility to be malignant. T(2)-weighted fat suppression series on 3.0TMRI was very important for discrimination of tumor histological characteristics.
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