Study on the scanning protocols for measuring bone mineral density by gemstone CT spectral imaging based on European spine phantom.

BACKGROUND: Gemstone spectral computed tomography (GSCT) has been used to measure bone mineral density (BMD) in human vertebrae and animal models gradually. PURPOSE: To investigate the effect of scanning protocols for BMD measurements by GSCT using the European spine phantom (ESP) and its accuracy and precision. MATERIAL AND METHODS: The ESP number 145 containing three hydroxyapatite (HAP) inserts with densities of 50, 100, and 200 mg/cm3 were labeled as L1, L2, and L3, respectively. Quantitative CT (QCT) protocol and 14 groups of scanning protocols configured by GSCT were used to repeatedly scan the ESP 10 times. Their measurements were compared with the true values of ESP and their relative standard deviation and relative error were calculated. RESULTS: The measured values of the three inserts at different exposure levels were statistically significant (P < 0.05). The measured values in the 0.8 s/r 260 mA group, 0.5 s/r 630 mA group, and 0.6 s/r 640 mA group were not significantly different from the actual ESP values for L1 and L2. However, the measured values at all the parameters were significantly different from the actual values for the L3. CONCLUSION: CT gemstone spectral imaging can accurately and quantitatively measure the HAP value of ESP, but the results of BMD will be affected by the scanning protocols. The best scanning parameter of ESP measured by GSCT was 0.8 s/r 260 mA, taking dose into consideration, and the measurement accuracy of vertebrae with low BMD was higher than that of QCT under this parameter.

Effect of abdominal adipose content on spine phantom bone mineral density measured by rapid kilovoltage-switching dual-energy CT and quantitative CT.

Background: The purpose of this study was to investigate the effect of abdominal adiposity, as measured by abdominal total adipose tissue (TAT), on the accuracy of rapid kilovoltage-switching dual-energy computed tomography (DECT) and quantitative computed tomography (QCT) measurements of bone mineral density (BMD) in a spine phantom model. Methods: Fresh porcine fat was wrapped around the European Spine Phantom (ESP) and divided into four groups according to the TAT cross-sectional areas, S=0, 100, 200, and 350 cm2, to simulate different TAT contents. The hydroxyapatite (HAP) (water) values of each vertebra were measured by DECT, and the BMD values by QCT. A one-sample t-test was used to analyze the differences between the measurements and the true values of the ESP. One-way analysis of variance (ANOVA) was applied to compare the differences between measurements under different TAT conditions, and the root-mean-square errors (RMSEs) of the BMD measurements were calculated and compared. Moreover, Pearson's correlation analysis was performed for the RMSE and TAT. Linear regression analysis was conducted on the measurements, the true values, and the TAT to obtain the correction equations for the BMD and to compare the RMSE before and after correction. Results: At higher TAT content, the measurements of both scanning methods were more affected, and the measurements of the TAT =350 cm2 group were significantly different from the remaining groups (P<0.05). There was a positive correlation between the RMSE and TAT (r>0, P<0.05), with the RMSE of the L1 vertebrae the largest under the same TAT content. The corrected equations for BMD were derived, and the RMSE of BMD was significantly reduced after correction. Conclusions: The measurements of ESP BMD for both rapid kilovoltage-switching DECT and QCT changed with TAT content. Along with the increase of TAT, the RMSE of measurements increased and the accuracy decreased; moreover, the lower the value of BMD, the more significant the RMSE. The linear regression analysis allowed the corrected BMD measurements to be very close to true values.

Comparison of pancreatic fat content measured by different methods employing MR mDixon sequence.

OBJECTIVE: To compare the reliability of different methods for measuring fat content of pancreas by MR modified Dixon(mDixon) Sequence and accurately evaluate pancreatic fat in as simple a way as possible. METHODS: This is a retrospective study, 64 patients were included in this study who underwent abdominal MR scan that contained the mDixon sequence from June 2019 to May 2020(Included 7 patients with type 2 diabetes and 4 patients with impaired glucose tolerance (IGT), they were admitted to hospital through the obesity clinic set up by endocrine department, all of them were initially diagnosed and untreated). All of the 64 patients were scanned in 3.0T MR (Philips Ingenia II) due to their condition, 10-34 slice pancreas images were obtained, which were different from each other. Three different methods of measurement were employed by two observers using Philips Intellispace Portal software: (1) All images (whole-pancreas) measurement, the whole-pancreatic fat fraction (wPFF) was calculated by software. (2) Interval slices measurement, that is half-pancreatic slices fat fraction (hPFF) measured in the same way, fat fraction obtained by the interlayer assay was calculated. (3) As usual, the fat content of pancreatic head, body and tail fat was measured respectively, and in order to improve credibility, we also measured head、 body and tail in every layer, and its average value was taken. The elapsed time of the above different measurement methods was recorded. Intra-group correlation coefficient (ICC) was used to analyze the consistency of the measured data within and between observers. T-tests and Friedman tests were applied to compare the difference of measured values among groups. RESULTS: No matter in normal person or diabetic or IGT, hPFF has shown good stability (ICChPFF = 0.988), and there was no significant difference compared with wPFF. But the average fat percentage composition of head, body and tail were significantly different from wPFF and hPFF (P < 0.01). At the same time, compared with normal person, pancreatic fat content in IGT and diabetic patients showed progressive significance(P<0.05). CONCLUSION: The distribution of pancreatic fat is not uniform, the method of measuring half pancreas by interlayer data collection can reflect the fat content of the entire pancreas, this suggests that measuring 50% of the pancreas is sufficient, this method effectively saves time and effort without affecting the results, which may have a better clinical application prospect.

Diagnostic accuracy assessment of molecular prediction model for the risk of NAFLD based on MRI-PDFF diagnosed Chinese Han population.

BACKGROUND: Several molecular prediction models based on the clinical parameters had been constructed to predict and diagnosis the risk of NAFLD, but the accuracy of these molecular prediction models remains need to be verified based on the most accurate NAFLD diagnostic method. The aim of this study was to verify the accuracy of three molecular prediction models Fatty liver index (FLI), NAFLD liver fat score system (NAFLD LFS), and Liver fat (%) in the prediction and diagnosis of NAFLD in MRI-PDFF diagnosed Chinese Han population. PATIENTS AND METHODS: MRI-PDFF was used to diagnose the hepatic steatosis of all the subjects. Information such as name, age, lifestyle, and major medical histories were collected and the clinical parameters were measured by the standard clinical laboratory techniques. The cut-off values of each model for the risk of NAFLD were calculated based on the MRI-PDFF results. All data were analyzed using the statistical analysis software SPSS 23.0. RESULTS: A total of 169 subjects were recruited with the matched sex and age. The ROC curves of FLI, NAFLD LFS, and Liver fat (%) models were plotted based on the results of MRI-PDFF. We founded that the accuracy of FLI, NAFLD LFS, and Liver fat (%) models for the prediction and diagnosis of NAFLD were comparative available in Chinese Han population as well as the validity of them in other ethnics and regions. CONCLUSIONS: The molecular prediction models FLI, NAFLD LFS, and Liver fat (%) were comparative available for the prediction and diagnosis of NAFLD in Chinese Han population. MRI-PDFF could be used as the golden standard to develop the new molecular prediction models for the prediction and diagnosis of NAFLD.

Intratumoral Injection of Hypertonic Glucose in Treating Refractory Pneumothorax Caused by Microwave Ablation: a Preliminary Study.

PURPOSE: The purpose of this technical report is to describe the technique of intratumoral injection of hypertonic glucose combined with low-negative pressure drainage to treat refractory pneumothorax (RP) after microwave ablation (MWA) of lung tumors. MATERIALS AND METHODS: Between September 2016 and May 2018, four patients who developed RP after MWA of peripheral lung cancer were managed by a combined method, including intratumoral injection of hypertonic glucose and catheter drainage under low-negative pressure. Blood gas values were recorded and compared before the treatment and one-week posttreatment. All patients were followed up for at least one month to monitor the possible recurrence of pneumothorax by chest CT. RESULTS: All patients were successfully treated. One patient received the intratumoral injection of hypertonic glucose twice, while the remaining three patients received a single injection. The technical success rate was 100%. Dyspnea related to RP was significantly relieved in all patients, and PaO2 and SaO2 values were higher than those measured before treatment. No patient suffered a recurrence of pneumothorax during the follow-up. CONCLUSION: The combined method of intratumoral injection of hypertonic glucose and continuous catheter drainage under low-negative pressure might be an effective method to manage RP caused by MWA.

Assessing Aortic Remodeling after Thoracic Endovascular Aortic Repair (TEVAR) in DeBakey IIIb Aortic Dissection: A Retrospective Study.

PURPOSE: This study analyzed the different levels of aortic remodeling in patients with DeBakey IIIb aortic dissection (AD) after thoracic endovascular aortic repair (TEVAR) at a single center. METHODS: In all, 66 patients with DeBakey IIIb AD who underwent TEVAR in the acute (Group A) or subacute phase (Group SA) from January 2012 to October 2016 were included in the study. The change in aortic lumen (A), true lumen (TL), false lumen (FL), and true lumen index (TLi) at different levels were analyzed. RESULTS: There was no statistically significant difference in the clinical information and morphologic imaging findings in Groups A and SA. At proximal levels (levels A-C), there was no difference in aortic remodeling parameters, that is, increased TL, decreased FL, and increased TLi at levels B and C and stable A at levels A-C, in both groups. Moreover, the above parameters were illustrated using a box-and-whisker plot, which revealed the unstable acute phase by the larger distribution interval and the median and abnormal values of the right skew distribution in Group A. CONCLUSION: Postoperative surveillance is important for patients of both acute and subacute AD.

Effect of CLU genetic variants on cerebrospinal fluid and neuroimaging markers in healthy, mild cognitive impairment and Alzheimer's disease cohorts.

The Clusterin (CLU) gene, also known as apolipoprotein J (ApoJ), is currently the third most associated late-onset Alzheimer's disease (LOAD) risk gene. However, little was known about the possible effect of CLU genetic variants on AD pathology in brain. Here, we evaluated the interaction between 7 CLU SNPs (covering 95% of genetic variations) and the role of CLU in ß-amyloid (Aß) deposition, AD-related structure atrophy, abnormal glucose metabolism on neuroimaging and CSF markers to clarify the possible approach by that CLU impacts AD. Finally, four loci (rs11136000, rs1532278, rs2279590, rs7982) showed significant associations with the Aß deposition at the baseline level while genotypes of rs9331888 (P = 0.042) increased Aß deposition. Besides, rs9331888 was significantly associated with baseline volume of left hippocampus (P = 0.014). We then further validated the association with Aß deposition in the AD, mild cognitive impairment (MCI), normal control (NC) sub-groups. The results in sub-groups confirmed the association between CLU genotypes and Aß deposition further. Our findings revealed that CLU genotypes could probably modulate the cerebral the Aß loads on imaging and volume of hippocampus. These findings raise the possibility that the biological effects of CLU may be relatively confined to neuroimaging trait and hence may offer clues to AD.

Impact of SORL1 genetic variations on MRI markers in non-demented elders.

The sorting protein-related receptor 1 (SORL1 or LR11) gene has been verified to play an important role in the pathologic process of ß-amyloid (Aß) formation and trafficking in Alzheimer's Disease (AD) by plenty of cytological and molecular biological studies. But there were few studies investigated the association of SORL1 gene and neurodegeneration features from a rather macroscopic perspective. In the present study, we explored the effect of SORL1 genotypes on AD-related brain atrophy. We recruited 812 individuals with both baseline and two-year follow-up information from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database and applied multiple linear regression models to examine the association between eight single nucleotide polymorphisms (SNPs) and neuroimaging phenotypes. Finally, four SNPs (rs11219350, rs2298813, rs3781836, rs3824968) showed trend of association with the volume of hippocampus and parahippocampal gyrus but failed to survive the false discovery rate (FDR) correction. Only rs1784933 and rs753780 showed significant association with right parahippocampal gyrus. According to our findings, SORL1 variations influence the atrophy of specific AD-related brain structures, which suggested the potential role of SORL1 in the neurodegeneration of cognitive related regions.

The impact of PICALM genetic variations on reserve capacity of posterior cingulate in AD continuum.

Phosphatidylinositolbinding clathrin assembly protein (PICALM) gene is one novel genetic player associated with late-onset Alzheimer's disease (LOAD), based on recent genome wide association studies (GWAS). However, how it affects AD occurrence is still unknown. Brain reserve hypothesis highlights the tolerant capacities of brain as a passive means to fight against neurodegenerations. Here, we took the baseline volume and/or thickness of LOAD-associated brain regions as proxies of brain reserve capacities and investigated whether PICALM genetic variations can influence the baseline reserve capacities and the longitudinal atrophy rate of these specific regions using data from Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. In mixed population, we found that brain region significantly affected by PICALM genetic variations was majorly restricted to posterior cingulate. In sub-population analysis, we found that one PICALM variation (C allele of rs642949) was associated with larger baseline thickness of posterior cingulate in health. We found seven variations in health and two variations (rs543293 and rs592297) in individuals with mild cognitive impairment were associated with slower atrophy rate of posterior cingulate. Our study provided preliminary evidences supporting that PICALM variations render protections by facilitating reserve capacities of posterior cingulate in non-demented elderly.

The Impact of UNC5C Genetic Variations on Neuroimaging in Alzheimer's Disease.

UNC5C, which is a transmembrane receptor for netrin-1 to trigger the apoptosis, has been confirmed as a new risk factor for Alzheimer's disease (AD) recently. However, there is lack of the evidence on the brain structure associated with the polymorphisms of UNC5C in AD. The objective of this study is to investigate the influence of UNC5C loci on the neuroimaging of strategic regions of AD. In 812 subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset, we explored the genotypes of UNC5C loci in the volumes of the hippocampus, parahippocampal gyrus, posterior cingulate gyrus, middle temporal and precuneus, and the thickness of the entorhinal cortex which are measured by magnetic resonance imaging (MRI). We also investigated the atrophy rate of above structures influenced by UNC5C loci using the longitudinal data. UNC5C loci were associated with the volume of right middle temporal (rs34585936 Pc = 0.0031). Meanwhile, the polymorphisms of UNC5C loci could alter the atrophy rate of strategic regions especially the left hippocampus (rs72672784 Pc = 0.0090; rs13120458 Pc = 0.0434; rs34875919 Pc = 0.0434) and right precuneus (rs72672784 Pc = 0.0068; rs2001246 Pc = 0.0055; rs74690179 Pc = 0.0055). UNC5C genotypes were significantly associated with the volume of the middle temporal on MRI; meanwhile, UNC5C loci could alter the atrophy of strategic regions of AD such as the hippocampus and precuneus. And the above effects of polymorphisms of UNC5C were more obvious in the population with the impaired cognition than those with the normal cognition.

Common Variants in PLD3 and Correlation to Amyloid-Related Phenotypes in Alzheimer's Disease.

The phospholipase D3 (PLD3) gene has shown association with Alzheimer's disease (AD). However, the role of PLD3 common variants in amyloid-ß (Aß) pathology remains unclear. We examined the association of thirteen common single nucleotide polymorphisms (SNPs) with cerebrospinal fluid (CSF) Aß(1- 42) levels and florbetapir retention on florbetapir 18F amyloid positron emission tomography (AV45-PET) in a large population. We found that one SNP (rs11667768) was significantly associated with CSF Aß(1- 42) levels in the normal cognition group. We did not observe an association of any SNP with florbetapir retention. Our study predicted the potential role of PLD3 variants in Aß pathology.

[The investigation of clinical images of 88 hospital staff with SARS].

OBJECTIVE: To investigate the clinical thoracic images of hospital staff with SARS. METHODS: Thoracic images was analyzed in 88 medical workers with SARS, including 394 chest plain films and 9 CT scans. RESULTS: The typical signs of SARS are multifocal air-space consolidations, and progress over a day from small shadow to becoming generalized. CONCLUSION: Thoracic plain film was necessary for diagnosis of SARS, CT could detect the pulmonary abnormality of SARS early.