Effect of Heart Rate and Coronary Calcification on the Diagnostic Accuracy of the Dual-Source CT Coronary Angiography in Patients with Suspected Coronary Artery Disease

Lingdong Meng,,Lianqun Cui,Yuntao Cheng,Xiaoyan Wu,Yuansheng Tang,Yong Wang,Fayun Xu 대한영상의학회 2009 Korean Journal of Radiology Vol.10 No.4

Objective: To evaluate the diagnostic accuracy of a dual-source computed tomography (DSCT) coronary angiography, with a particular focus on the effect of heart rate and calcifications. Materials and Methods: One hundred and nine patients with suspected coronary disease were divided into 2 groups according to a mean heart rate (< 70 bpm and ≥ 70 bpm) and into 3 groups according to the mean Agatston calcium scores (≤ 100, 101-400, and > 400). Next, the effect of heart rate and calcification on the accuracy of coronary artery stenosis detection was analyzed by using an invasive coronary angiography as a reference standard. Coronary segments of less than 1.5 mm in diameter in an American Heart Association (AHA) 15-segment model were independently assessed. Results: The mean heart rate during the scan was 71.8 bpm, whereas the mean Agatston score was 226.5. Of the 1,588 segments examined, 1,533 (97%) were assessable. A total of 17 patients had calcium scores above 400 Agatston U, whereas 50 had heart rates ≥ 70 bpm. Overall the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) for significant stenoses were: 95%, 91%, 65%, and 99% (by segment), respectively and 97%, 90%, 81%, and 91% (by artery), respectively (n = 475). Heart rate showed no significant impact on lesion detection; however, vessel calcification did show a significant impact on accuracy of assessment for coronary segments. The specificity, PPV and accuracy were 96%, 80%, and 96% (by segment), respectively for an Agatston score less than 100% and 99%, 96% and 98% (by artery). For an Agatston score of greater to or equal to 400 the specificity, PPV and accuracy were reduced to 79%, 55%, and 83% (by segment), respectively and to 79%, 69%, and 85% (by artery), respectively. Conclusion: The DSCT provides a high rate of accuracy for the detection of significant coronary artery disease, even in patients with high heart rates and evidence of coronary calcification. However, patients with severe coronary calcification (> 400 U) remain a challenge to diagnose. Objective: To evaluate the diagnostic accuracy of a dual-source computed tomography (DSCT) coronary angiography, with a particular focus on the effect of heart rate and calcifications. Materials and Methods: One hundred and nine patients with suspected coronary disease were divided into 2 groups according to a mean heart rate (< 70 bpm and ≥ 70 bpm) and into 3 groups according to the mean Agatston calcium scores (≤ 100, 101-400, and > 400). Next, the effect of heart rate and calcification on the accuracy of coronary artery stenosis detection was analyzed by using an invasive coronary angiography as a reference standard. Coronary segments of less than 1.5 mm in diameter in an American Heart Association (AHA) 15-segment model were independently assessed. Results: The mean heart rate during the scan was 71.8 bpm, whereas the mean Agatston score was 226.5. Of the 1,588 segments examined, 1,533 (97%) were assessable. A total of 17 patients had calcium scores above 400 Agatston U, whereas 50 had heart rates ≥ 70 bpm. Overall the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) for significant stenoses were: 95%, 91%, 65%, and 99% (by segment), respectively and 97%, 90%, 81%, and 91% (by artery), respectively (n = 475). Heart rate showed no significant impact on lesion detection; however, vessel calcification did show a significant impact on accuracy of assessment for coronary segments. The specificity, PPV and accuracy were 96%, 80%, and 96% (by segment), respectively for an Agatston score less than 100% and 99%, 96% and 98% (by artery). For an Agatston score of greater to or equal to 400 the specificity, PPV and accuracy were reduced to 79%, 55%, and 83% (by segment), respectively and to 79%, 69%, and 85% (by artery), respectively. Conclusion: The DSCT provides a high rate of accuracy for the detection of significant coronary artery disease, even in patients with high heart rates and evidence of coronary calcification. However, patients with severe coronary calcification (> 400 U) remain a challenge to diagnose.

Study on the Influence of Formation Temperature on the Water Absorption and Weathering of Swelling Rock in Marine Coal Mines

Lingdong Meng,Lijun Han,Hexuan Zhu,Wenlong Dong,Wei Li 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

To study the mechanisms and potential control measures for coal mine engineering safety hazards caused by swelling rock, water absorption experiments were performed under different temperature by using an independently developed rock water absorption test system. The swelling pressure, expansion amount and water absorption amount of specimens were monitored in real time. Nuclear magnetic resonance and uniaxial compression experiments were performed. The water absorption rate of the swelling rock specimens increases significantly with increasing water absorption time. The water absorption capacity of the specimens differs considerably under different temperatures. The water absorption curve can be divided into three stages: the severe stage, deceleration stage and equilibrium stage. The water absorption amount and water absorption rate are linearly related to temperature. The curve of the swelling pressure depicts a double peak shape. The expansion curve can also be divided into three stages. With increasing temperature, the expansion rate increases, and the time needed to achieve expansion stability is prolonged. There is a negative linear correlation between the uniaxial compressive strength and the moisture content. The higher the temperature is, the higher the moisture content. The increase in the rock porosity after water absorption is one of the important factors driving the strength attenuation.

Study of the Effects of Compaction and Split Grouting on the Structural Strengthening Characteristics of Weakly Cemented Argillaceous Rock Masses

Lingdong Meng,Lijun Han,Hexuan Zhu,Wenlong Dong,Wei Li 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.4

There is a wide distribution of weakly cemented argillaceous rock masses in areas where there are many coal mines, and their complex characteristics make them more difficult to support. This paper researches this type of rock and studies the slurry diffusion mechanism and grouting reinforcement characteristics of injected rock mass and their relationship with compaction and splitting grouting. The grouting mode is dominated by compaction and splitting. The rheological behavior of cement slurries with different concentrations used in split grouting was studied. The existing grouting equipment was improved, and grouting tests were performed on loose aggregates of weakly cemented primary rock in a certain size range. Subsequently, basic physical parameter determination tests, microscopic tests, and uniaxial tests were performed on grout, and the effects of grouting pressure, moisture content of standard samples, slurry water/cement ratio, and curing time on grouting reinforcement were analyzed. During the grouting process, the pattern of plasma pulse diffusion and reinforcement was summarized as three types: compaction, splitting, and microcracking. The failure modes of rock were summarized as shear failure, shear failure along the interface of the plasma, and splitting damage.

Inhibitory Effects of Crocetin On High Glucose-induced Apoptosis in Cultured Human Umbilical Vein Endothelial Cells and Its Mechanism

Meng, Lingdong,Cui, Lianqun 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.3

Dysfunction of endothelial cell is considered as a major cause of vascular complications in diabetes. Crocetin has been shown to have strong antioxidant activities. In present study, we tested whether crocetin inhibited high glucose-induced apoptosis in cultured human umbilical vein endothelial cells $(HUVEC_s)$ and to explore its possible mechanism. Exposure to high glucose (33 mM) for 72h induced a pronounced increase in apoptosis compared with normal glucose (5.5 mM),as evaluated by cell chromatin staining with Hoechst 33,258 and cell death detection ELISA. High glucose attenuated activation of Akt and endothelial nitric oxide synthase (eNOS). Crocetin (0.1 ${\mu}M$, 1.0 ${\mu}M$) prevented high glucose-induced apoptosis, which correlates with the increase of activation of p-Akt, following the up-regulation of eNOS and NO production. Pretreatment with phosphatidylinositol 3' kinase (PI3K) inhibitor LY294002 or eNOS inhibitor $N^G-nitro-$ arginine methyl ester (LN or L-NAME) inhibited crocetin' effect on p-Akt or eNOS, respectively. For the first time, results of our study suggest that crocetin inhibits high glucose-induced apoptosis, at least partly, via PI3K/Akt/eNOS pathway in $(HUVEC_s)$ and crocetin may exert a beneficial effect in preventing diabetes-associated cardiovascular complications.

Inhibitory Effects of Crocetin On High Glucose-induced Apoptosis in Cultured Human Umbilical Vein Endothelial Cells and Its Mechanism

Lingdong Meng,Lianqun Cui 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.3

Dysfunction of endothelial cell is considered as a major cause of vascular complications in diabetes. Crocetin has been shown to have strong antioxidant activities. In present study, we tested whether crocetin inhibited high glucose-induced apoptosis in cultured human umbilical vein endothelial cells (HUVECS) and to explore its possible mechanism. Exposure to high glucose (33 mM) for 72h induced a pronounced increase in apoptosis compared with normal glucose (5.5 mM),as evaluated by cell chromatin staining with Hoechst 33,258 and cell death detection ELISA. High glucose attenuated activation of Akt and endothelial nitric oxide synthase (eNOS). Crocetin (0.1 µM, 1.0 µM) prevented high glucose-induced apoptosis, which correlates with the increase of activation of p-Akt, following the up-regulation of eNOS and NO production. Pretreatment with phosphatidylinositol 3' kinase (PI3K) inhibitor LY294002 or eNOS inhibitor NG-nitro- arginine methyl ester (LN or L-NAME) inhibited crocetin' effect on p-Akt or eNOS, respectively. For the first time, results of our study suggest that crocetin inhibits high glucose-induced apoptosis, at least partly, via PI3K/Akt/eNOS pathway in HUVECS and crocetin may exert a beneficial effect in preventing diabetes-associated cardiovascular complications.

The Split-Permeation Grouting Mechanism of Loose and Broken Coal Rock Masses considering the Temporal and Spatial Characteristics of Slurry Viscosity

Hexuan Zhu,Lijun Han,Qingbin Meng,Jun Liu,Lingdong Meng,Wenlong Dong 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5

Quick-setting grout has time-varying characteristics, and the space porosity of the injected medium changes after being grouted. The above two points need to be considered when loose and broken coal rock masses are grouted with rapid-setting grout. In other words, the coupling effect of the slurry-coal rock mass causes the slurry to exhibit the temporal and spatial characteristics of slurry viscosity (TSCSV). Based on the Bingham fluid constitutive model, a capillary group model with a linear increase in diameter was created, and a one-dimensional penetration grout diffusion model was established considering the TSCSV. The one-dimensional visualization splitting-permeation grout diffusion simulation test system was designed to obtain the space porosity of the broken coal rock mass under different final grouting pressures to obtain the law of the changes in grouting pressure and diffusion height with time under the condition of a fixed grouting rate. Furthermore, the mechanism of splitting-permeation grouting in loose and broken coal rock masses is analysed in depth considering the TSCSV. The results showed that the space porosity of coal rock masses increases linearly. In addition, the calculated value of the slurry diffusion distance was 0.93 − 1.1 times the experimental value considering the TSCSV. The calculated value was in good agreement with the experimental value. The calculated value of the final pressure of orifice grouting was approximately 1.5 times the test value without considering the unevenness of the space porosity distribution (USPD). The grouting pressure was overestimated without considering the USPD. Therefore, the TSCSV of the quick-setting slurry should be fully considered in the grouting design.