1.LncRNA-UCA1-microRNA-143-Notch1 regulates autophagy in myocardial ischemia reperfusion injury induced by cardiopulmonary bypass.
Lingzhi JIANG ; Mingshan WANG ; Ye SHEN
Chinese Critical Care Medicine 2025;37(6):576-582
OBJECTIVE:
To observe the degree of myocardial cell injury and the changes in autophagy level in rats with myocardial ischemia/reperfusion (I/R) injury induced by cardiopulmonary bypass (CPB), and to explore the regulatory role of the long non-coding RNA-urothelial carcinoma antigen 1-microRNA-143-Notch1 axis (lncRNA-UCA1-miR-143-Notch1 axis) in myocardial I/R injury induced by CPB.
METHODS:
Healthy male Sprague-Dawley (SD) rats were randomly divided into the following groups using the random number method: Sham operation (Sham) group, myocardial I/R injury model group (model group), empty lentivirus group, lncRNA-UCA1 upregulation group, miR-143 downregulation group, and lncRNA-UCA1 upregulation+miR-143 upregulation group, with 9 rats in each group. The rat model of myocardial I/R injury induced by CPB was established by thoracotomy aortic ligation under cardiopulmonary bypass support; in the Sham group, only threading was performed without ligation, and other procedures were the same. Seventy-two hours before modeling, the lncRNA-UCA1 upregulated group was injected with 100 μL of myocardial tissue-specific adeno-associated virus (AAV) overexpression vector of lncRNA-UCA1 via tail vein, the miR-143 downregulated group was injected with 100 μL of AAV short hairpin RNA (shRNA) vector of miR-143 via tail vein, the lncRNA-UCA1 upregulation+miR-143 upregulation group was injected with 100 μL of myocardial tissue-AAV overexpression vector of lncRNA-UCA1 and 100 μL of AAV overexpression vector of miR-143 via tail vein, and the empty vector lentivirus group was injected with 100 μL of AAV empty vector (virus titers were 1×109 TU/mL); the Sham group and the model group were injected with equal amounts of normal saline. The animals were euthanized 24 hours after intervention and cardiac tissue specimens were collected. After hematoxylin eosin (HE) staining, the damage of myocardial cells and the changes of muscle fiber tissue were observed under a light microscope; after dual staining with uranyl acetate and lead citrate, the ultrastructural damage of heart tissue was observed under a transmission electron microscopy; the expression of lncRNA-UCA1, miR-143, and Notch1 mRNA in myocardial tissue was detected by real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-PCR); the expression of microtubule 1 light chain 3-II/I (LC3-II/I) and Notch1 protein in myocardial tissue was detected by Western blotting.
RESULTS:
Compared with the Sham group, the myocardial cells of rats in the model group were enlarged, the intercellular space increased, autophagosomes increased, the arrangement of myocardial fibers was disordered, mitochondrial proliferated and deformed. The expression levels of lncRNA-UCA1 and Notch1 mRNA, as well as the protein expression levels of LC3-II/I and Notch1 were significantly increased, while the expression level of miR-143 was significantly decreased. Compared with the model group, the degree of myocardial cell injury in the lncRNA-UCA1 upregulation group and miR-143 downregulation group was significantly alleviated, the expression levels of Notch1 mRNA, LC3-II/I, and Notch1 protein were significantly increased [Notch1 mRNA (2-ΔΔCt): 2.66±0.24, 2.03±0.23 vs. 1.45±0.13, LC3-II/I: 2.10±0.21, 1.92±0.19 vs. 1.39±0.14, Notch1 protein (Notch1/GAPDH): 1.72±0.16, 1.57±0.16 vs. 1.34±0.13, all P < 0.05], and the expression level of miR-143 was significantly decreased (2-ΔΔCt: 0.50±0.06, 0.52±0.06 vs.0.71±0.06, P < 0.05). The expression level of lncRNA-UCA1 in the lncRNA-UCA1 upregulated group was significantly higher than that in the model group (2-ΔΔCt: 2.47±0.22 vs. 1.43±0.14, P < 0.05), while there was no significant difference in the miR-143 downregulation group compared with the model group (2-ΔΔCt: 1.50±0.16 vs. 1.43±0.14, P > 0.05). There was no significant difference in the degree of myocardial cell injury in the empty load lentivirus group and the lncRNA-UCA1 upregulation+miR-143 upregulation group compared to the model group. There were no significant differences in the expression of miR-143, Notch1 mRNA, and the autophagy level in these two groups compared to the model group. The expression level of lncRNA-UCA1 in the lncRNA-UCA1 upregulation+miR-143 upregulation group was significantly higher than that in the model group (2-ΔΔCt: 2.47±0.20 vs. 1.43±0.14, P < 0.05).
CONCLUSIONS
Autophagy is involved in the pathological process of myocardial I/R injury induced by CPB. The lncRNA-UCA1-microRNA-143-Notch1 axis may regulate the autophagy level to participate in the I/R injury process.
Animals
;
MicroRNAs
;
Rats, Sprague-Dawley
;
RNA, Long Noncoding
;
Male
;
Myocardial Reperfusion Injury/etiology*
;
Rats
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Cardiopulmonary Bypass/adverse effects*
;
Receptor, Notch1/metabolism*
;
Autophagy
2.The evaluation value of serum PTX3 and CK-MB levels on volume load in patients with chronic decompensated heart failure
Mingshan CAO ; Chundi WANG ; Xiaoqian HU ; Linghui MENG ; Yufeng WU ; Huan LIU ; Hua YANG
Journal of Chinese Physician 2024;26(1):87-92
Objective:To explore the evaluation value of serum levels of positive pentameric protein 3 (PTX3) and creatine kinase isoenzyme MB (CK-MB) on volume load in patients with chronic decompensated heart failure (CDHF).Methods:A total of 300 CDHF patients who visited the Xingtai Central Hospital from July 2019 to July 2022 were selected and divided into a capacity overload group ( n=182) and a non capacity overload group ( n=118) based on their capacity balance level. Two clinical data sets were compared and analyzed. The receiver operating characteristic (ROC) curve was used to analyze the evaluation value of serum PTX3 and CK-MB levels on the volume load of CDHF patients. The clinical disease characteristics of the two groups of patients were analyzed using univariate analysis, and the influencing factors of volume load of CDHF patients were analyzed using logistic regression. A column chart model was constructed and validated. Results:The body mass index (BMI), waist circumference, systolic blood pressure, diastolic blood pressure, fasting blood glucose (FBG), glycosylated hemoglobin (HbA 1c), C-reactive protein (CRP), uric acid (UA), homeostasis model assessment of insulin resistance (HOMA-IR) of patients in the capacity overload group were higher than those in the non-capacity overload group, and the differences were statistically significant (all P<0.05). The PTX3, CK-MB, pulmonary capillary wedge pressure (PCWP), and CVP levels of patients in the capacity overload group were higher than those in the non-capacity overload group, while albumin, hemoglobin, and hematocrit were lower than those in the non-capacity overload group, and the differences were statistically significant (all P<0.05). The ROC curve showed that the area under the curve (AUC) of PTX3 and CK-MB for predicting capacity overload in CDHF patients are 0.795 and 0.718, with sensitivity of 86.2% and 83.7%, specificity of 65.4% and 68.6%, respectively, indicating high predictive accuracy; The AUC of the two joint predictions is 0.817, the sensitivity was 92.5%, and the specificity was 70.6%. The prediction accuracy was higher than PTX3 ( Z=3.812, P<0.05) and CK-MB ( Z=3.365, P<0.05). PTX3, CK-MB, albumin, hemoglobin, hematocrit, PCWP, and central venous pressure (CVP) were all influencing factors of volume load status in CDHF patients (all P<0.05). The column chart risk prediction model established based on these factors had high accuracy and strong applicability in clinical treatment. Conclusions:Serum PTX3 and CK-MB levels are influencing factors for volume overload in CDHF patients. A column chart model constructed in combination with indicators such as albumin, hemoglobin, hematocrit, PCWP, and CVP has high predictive value for the volume overload status of CDHF.
3.Effect of electroacupuncture preconditioning on microglia polarization after cerebral ischemia reperfusion injury in rats
Xiangxiang ZHANG ; Qianyun TAO ; Haofei LIU ; Yang YUAN ; Mingshan WANG ; Gaofeng ZHANG
Chinese Journal of Geriatric Heart Brain and Vessel Diseases 2024;26(2):207-211
Objective To investigate the effect of electroacupuncture preconditioning on microglia polarization in rats after cerebral ischemia reperfusion(IR)injury and explore the role of tyrosine kinase 2(J AK2)/signal transducer and activator of transcription 3(STAT3)pathway in the process.Methods Forty-five clean-grade healthy male Sprague-Dawley rats were randomly and equally divided into sham operation group,IR group and electroacupuncture preconditioning group.Rat model of IR injury was induced with thread occlusion of the internal carotid artery.Before modeling,electroacupuncture preconditioning was applied to Baihui acupoint for 5 consec-utive days in the preconditioning group,and exposure of the cervical blood vessels were inflicted in the sham-operation group.At 24 h after reperfusion,the severity of neurological deficit was observed by modified neurological deficit score(mNSS),and the cerebral infarct volume was observed by TTC staining.Western blotting was used to detect the protein levels of classical acti-vated type(M1)marker inducible nitric oxide synthase(iNOS),alternative activated type(M2)marker arginase 1(Arg-1),JAK2 and p-JAK2,and STAT3 and p-STAT3,and q-PCR was applied to detect the mRNA expression of iNOS and Arg-1.The expression of TNF-α and IL-10 was measured by ELISA.Results Compared with the sham operation group,the mNSS,infarct vol-ume,protein levels of p-JAK2/JAK2,p-STAT3/STAT3,protein and mRNA levels of iNOS and Arg-1,and expression of TNF-α and IL-10 were significantly increased in the IR and electroacu-puncture preconditioning groups(P<0.01).The preconditioning group had obviously lower mNSS,smaller infarct volume,decreased protein levels of p-JAK2/JAK2,p-STAT3/STAT3,re-duced protein and mRNA levels of iNOS,and declined TNF-α expression,but elevated expression of Arg-1 at protein(2.0±0.2 vs 1.5±0.1)and mRNA(4.2±0.8 vs 3.1±0.3)levels and increased IL-10 expression(49.1±7.1 pg/mg vs 27.9±5.9 pg/mg)when compared with the IR group(P<0.01).Conclusion Electroacupuncture preconditioning can promote the polarization of microglia to M2 and inhibit the polarization of microglia to M1 after cerebral IR injury,which may be relat-ed to the inhibition of JAK2/STAT3 pathway.
4.Role of CIP2A in preoperative sleep deprivation-induced aggravation of postoperative cognitive dysfunction in aged mice
Yang LIU ; Huimin LI ; Hongyan GONG ; Miaomiao WEI ; Gaofeng ZHANG ; Mingshan WANG ; Fang ZHENG
Chinese Journal of Anesthesiology 2024;44(1):46-52
Objective:To evaluate the role of cancerous inhibitor of protein phosphatase 2A (CIP2A) in preoperative sleep deprivation (PSD)-induced aggravation of postoperative cognitive dysfunction (POCD) in aged mice.Methods:One hundred and ten healthy C57BL/6J mice of either sex, aged 18-20 months, weighing 29-35 g, were divided into 5 groups ( n=22 each) using a random number table method: sham operation group (S group), abdominal surgery group (O group), PSD + abdominal surgery group (D+ O group), CIP2A shRNA + abdominal surgery group (CS+ O group), and CIP2A shRNA+ PSD+ abdominal surgery group (CS+ D+ O group). At 14 days before surgery, control shRNA lentivirus was injected into the hippocampus in S, O and CS+ O groups, and CIP2A shRNA was injected into the hippocampus in D+ O and CS+ D+ O groups. PSD was carried out for 3 consecutive days prior to surgery. Cognitive function was assessed using the Morris water maze test at days 7-11 after surgery. The mice were sacrificed under deep anesthesia at day 3 after surgery, and hippocampal tissues were obtained to determine the expression of CIP2A, high mobility group box 1 (HMGB1), ionized calcium-binding adapter molecule 1 (Iba-1), alpha subunit of protein phosphatase 2A (PP2Aa), catalytic subunit of protein phosphatase 2A (PP2Ac), phosphorylated tau protein (p-tau) (S396), and p-tau (S404) (by Western blot), levels of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD), and count of Iba-1 positive cells in the hippocampal CA1 region (using immunofluorescence staining). Results:Compared with S group, the escape latency was significantly prolonged, the frequency of crossing the platform was reduced, duration of stay in the target quadrant was shortened, the expression of CIP2A, Iba-1 and HMGB1 was up-regulated, PP2Ac expression was down-regulated, levels of ROS and MDA and count of Iba-1 positive cells were increased, and the activity of SOD was decreased in O group ( P<0.05). Compared with O group, the escape latency was significantly prolonged, the frequency of crossing the platform was reduced, duration of stay in the target quadrant was shortened, the expression of CIP2A, Iba-1 and HMGB1 was up-regulated, PP2Ac expression was down-regulated, levels of ROS and MDA and count of Iba-1 positive cells were increased, and the activity of SOD was decreased in D+ O group, and the escape latency was significantly shortened, the frequency of crossing the platform was increased, duration of stay in the target quadrant was prolonged, the expression of CIP2A, Iba-1 and HMGB1 was down-regulated, PP2Ac expression was up-regulated, levels of ROS and MDA and count of Iba-1 positive cells were decreased, and the activity of SOD was increased in CS+ O group ( P<0.05). Compared with D+ O group, the escape latency was significantly shortened, the frequency of crossing the platform was increased, duration of stay in the target quadrant was prolonged, the expression of CIP2A, Iba-1 and HMGB1 was down-regulated, PP2Ac expression was up-regulated, levels of ROS and MDA and count of Iba-1 positive cells were decreased, and the activity of SOD was increased in CS+ D+ O group ( P<0.05). There was no significant difference in PP2Aa expression among the five groups ( P>0.05). Conclusions:The mechanism by which PSD aggravates POCD is related to up-regulating the expression of CIP2A and promoting oxidative stress responses, neuroinflammatory responses and phosphorylation of tau protein in aged mice.
5.A study on rare compound heterozygous mutations in SERPINC1 gene and their mechanisms
Ke ZHANG ; Shuangnü LIN ; Haixiao XIE ; Longying YE ; Langyi QIN ; Jingye PAN ; Lihong YANG ; Mingshan WANG
Chinese Journal of Laboratory Medicine 2024;47(3):301-307
Objective:Molecular mechanisms underlying compound heterozygous mutations in a patient with inherited antithrombin (AT) deficiency.Methods:The proband was admitted to the First Affiliated Hospital of Wenzhou Medical University in November 2018 with a one-day history of sudden syncope and limb twitching. Peripheral venous blood was collected from the proband and members of his lineages, totaling nine persons across three generations, and a family lineage survey was conducted. AT activity (AT:A) was measured using a chromogenic substrate assay, while AT antigen (AT:Ag) was detected through an immunoturbidimetric assay. Mutation sites were identified by means of Sanger sequencing of the SERPINC1 gene, and silico tools were applied to predict the mutational conservation and hydrophobicity changes. Recombinant plasmid expression vectors were constructed and transfected into HEK293T cells for in vitro overexpression studies. The recombinant AT protein was characterized using Western Blotting, ELISA, and cellular immunofluorescence assays.Results:The proband was a 21-year-old man with type Ⅰ AT deficiency. His AT:A was 33%, along with a corresponding reduction in AT:Ag. The genetic analysis revealed there was a heterozygous insertion mutation at c.318_319insT (p.Asn107*) and a heterozygous missense mutation at c.922G>T (p.Gly308Cys) in exons 2 and 5, respectively. These mutation sites were entirely conserved among the homologous species. Additionally, hydrophobicity studies showed that the p.Gly308Cys mutation will decrease the hydrophilicity of amino acid residues 307-313. The in vitro expression studies indicated a reduction of approximately 46.98%±2.94% and 41.35%±1.48% in the amount of recombinant protein AT-G308C in transfected cell lysates and culture supernatants, respectively. Treatment with the proteasome inhibitor (MG132) restored the cytoplasmic levels of AT-G308C protein to a level similar to that of wild-type protein. However, neither cell lysate nor culture supernatant demonstrated the presence of the recombinant protein AT-N107*. Conclusions:The heterozygous insertion mutation of p.Asn107* and the heterozygous missense mutation of p.Gly308Cys have been associated with reduced AT levels in proband. The p.Asn107* heterozygous insertion mutation may initiate the degradation of mRNA via nonsense mutation-mediated mechanisms, which would remove the defective transcripts, as well as the p.The Gly308Cys heterozygous missense mutation may cause the AT protein to undergo proteasome-dependent degradation by modifying the hydrophobicity of nearby residues in the cytoplasm.
6.Clinical features and gene mutation analysis of fifteen probands with hereditary coagulation factor Ⅴ deficiency
Shuangnv LIN ; Yincai YE ; Bile CHEN ; Zuoting XIE ; Mingshan WANG
Chinese Journal of Clinical Laboratory Science 2024;42(6):425-429
Objective To analyze the clinical features and gene mutations types of 15 unrelated probands with coagulation factor Ⅴ(FⅤ)deficiency,and explore the possible molecular pathogenesis.Methods FⅤ activity(FⅤ∶C)and FⅤ antigen(FⅤ∶Ag)were detected by one-stage clotting and ELISA,respectively.All 25 exons of the F5 gene in the patients were amplified by PCR,and se-quenced directly.Haplotype analysis was performed with different polymorphisms on FⅤ.Protein modeling was applied to analyze the potential molecular mechanisms.Results Of the 5 probands with an FⅤ∶C greater than 10%,only 1 had minor bleeding symptoms.In the 10 probands with FⅤ∶C less than 10%,seven showed various bleeding manifestations.A total of 12 gene mutations locus were de-tected from 15 probands(8 gene mutations locus were novel mutations,and 1 was pathogenic polymorphism).An in silico analysis pre-liminarily investigated the potential pathogenic mechanism of the mutation.Modeling analysis showed that all the six missense mutations would lead to conformational alterations in the FⅤ protein.Among them,two(p.Ser1781 Arg and p.Asp96His)would decrease hydro-gen bonds.Conclusion The level of FⅤ in these probands with inherited FⅤ deficiency were associated with mutations in the respec-tive F5 gene,and the FⅤ levels strongly correlated with the probability of hemorrhage.
7.Analysis of three Chinese pedigrees affected with Hereditary factor Ⅶ deficiency due to compound heterozygous variants of F7 gene
Longying YE ; Huilin CHEN ; Zhengxian SU ; Ke ZHANG ; Lihong YANG ; Yanhui JIN ; Mengzhen WEN ; Mingshan WANG
Chinese Journal of Medical Genetics 2024;41(4):393-398
Objective:To analyze the types of genetic variants and clinical characteristics of three Chinese pedigrees affected with Hereditary coagulation factor Ⅶ (FⅦ) deficiency.Methods:Three pedigrees who had visited the First Affiliated Hospital of Wenzhou Medical University between December 2021 and October 2022 were selected as the study subjects. Prothrombin time (PT), activated partial thromboplastin time (APTT) and FⅦ activity (FⅦ: C) were measured in the three probands and their pedigree members. All exons and their flanking sequences were analyzed by direct sequencing, and candidate variants were verified by reverse sequencing. The corresponding variant loci in the family members were also analyzed. ClustalX-2.1-win was used to analyze the conservation of the variant loci. Varcards and Spcards online software was used to predict the pathogenicity of the variants. Pymol software was used to analyze the changes in protein structure and molecular forces.Results:Three cases of hereditary FⅦ deficiency were found to have decreased FⅦ: C, prolonged PT and normal APTT. Genetic analysis identified a total of four genetic variants, and all three probands had harbored compound heterozygous variants of the F7 gene, including p. Cys389Gly and p. His408Gln in proband 1, p. Cys389Gly and IVS6+ 1G>T in proband 2, and IVS6+ 1G>T and IVS1a+ 5G>A in proband 3. Conservation analysis showed that both the p. Cys389 and p. His408 loci are highly conserved among orthologous species. Analysis with Varcards and Spcards software showed that these variants were pathogenic. Protein modeling analysis showed that the p. Cys389Gly and p. His408Gln variants may result in altered protein structures and changes in hydrogen bonds. Conclusion:The clinical manifestations of the three FⅦ-deficient probands may be attributed to the compound heterozygous variants of p. Cys389Gly/p.His408Gln, p. Cys389Gly/ⅠⅤS6+ 1G>T and ⅠⅤS6+ 1G>T/ⅠⅤS1a+ 5G>A of the F7 gene. The combination of the three compound heterozygous variants was unreported previously.
8.Analysis of two consanguineous Chinese pedigrees affected with Hereditary prokallikrein deficiency and High molecular weight kininogen deficiency
Bile CHEN ; Zuoting XIE ; Zhou ZHENG ; Yuan CHEN ; Huilin CHEN ; Mingshan WANG ; Yanhui JIN
Chinese Journal of Medical Genetics 2024;41(9):1066-1071
Objective:To analyze the genetic variants of two consanguineous Chinese pedigrees affected with Hereditary prokallikrein (PK) and High molecular weight kininogen (HMWK) deficiency and explore their molecular pathogenesis.Methods:A PK deficiency pedigree (10 individuals from 4 generations) and a HMWK deficiency pedigree (6 individuals from 3 generations) which were admitted to the First Affiliated Hospital of Wenzhou Medical University on December 3, 2021 and June 16, 2022, respectively were selected as the study subjects. Clinical data of the two pedigrees were collected, and the related coagulation indexes of the probands and their family members were determined. Genomic DNA of the two pedigrees was extracted from peripheral blood samples. This study was approved by the First Affiliated Hospital of Wenzhou Medical University (Ethics No. KY2022-R193).Results:The plasma PK activity of proband A, a 29-year-old female, and her brother were extremely low (< 1.0%). Proband B was a 66-year-old male with extremely low plasma HMWK activity (< 1.0%). Genetic sequencing revealed that the proband A and her brother had both harbored a homozygous c. 417_418insCATTCTTA (p.Arg140Hisfs*3) insertional variant in exon 5 of the KLKB1 gene, with her grandmother, maternal grandmother, father, mother, sister and son all carrying heterozygous insertion variant, and her ancestor father and husband are both wild-type. Proband B had harbored a homozygous c. 460C>A (p.Pro154Thr) missense variant in exon 4 of the KNG1 gene, and his son carries a heterozygous missense variant. All other members of the pedigree are wild type. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variants were respectively rated as pathogenic (PVS1+ PM2_Supporting+ PM4) and likely pathogenic (PS4+ PM2_Supporting+ PP3+ PP4). Conclusion:The c. 417_418insCATTCTTA (p.Arg140Hisfs*3) variant of the KLKB1 gene and the c. 460C>A (p.Pro154Thr) variant of the KNG1 gene probably underlay the decreased PK and HMWK activities in the two pedigrees, respectively.
9.Molecular mechanism analysis of a family with hereditary coagulation F Ⅺ deficiency caused by compound heterozygous mutations
Yuan CHEN ; Langyi QIN ; Shuangnyu LIN ; Lihong YANG ; Ke ZHANG ; Longying YE ; Yanhui JIN ; Mingshan WANG
Chinese Journal of Hematology 2024;45(3):294-298
A 34 year old female patient was scheduled to undergo surgical resection due to a "breast nodule". Preoperative examination revealed an activated partial thromboplastin time (APTT) of 66.2 seconds, coagulation factor Ⅺ activity (FⅪ: C) of 2%, and FⅪ antigen (FⅪ: Ag) of 40.3%. The patient and family members showed no abnormal bleeding symptoms. Diagnosed as hereditary coagulation factor Ⅺ deficiency. Genetic testing revealed that the F11 gene had a heterozygous nonsense mutation in exon 10, c.1107C>A (p.Tyr351stop), and a heterozygous missense mutation in exon 13, c.1562A>G (p.Tyr503Cys). The father and son were p Heterozygous carriers of Tyr351stop mutation, while the mother and daughter are p Heterozygous carriers of Tyr503Cys mutations. The in vitro expression results showed that p The Tyr351stop mutation resulted in a significant decrease in the transcription level of F11 gene, while p The Tyr503Cys mutation has no effect on the transcription level and protein expression level of F11 gene, but it leads to a significant decrease in the level of FⅪ:C in the cell culture supernatant.
10.Optimal phases of reconstructed CT images under different heart rates based on dynamic phantom system of left ventricle and coronary arteries
Jinlei CHEN ; Hongjie LI ; Mingshan CHEN ; Xuemin WANG
Chinese Journal of Medical Imaging Technology 2024;40(6):917-921
Objective To explore the optimal phases of reconstructed CT images under different heart rates based on dynamic phantom system simulating the motion of left ventricle and coronary arteries.Methods A dynamic phantom system which could simulate the periodic movements of the heart at 50-120 beats per minute(bpm)and the output of electrocardiogram signals was constructed.CT scanning were performed in the simulated R-R interval,and images were reconstructed with every 10%interval between 0 to 90%phases.Then subjective image quality scoring was performed,and inter-observer consistency of image quality scores was assessed.Finally the qualities of reconstructed images were compared among different phases under different heart rates.Results The inter-observer consistency of subjective imaging quality scores was high(Kendall W=0.83,P<0.05).Under 50-60 bpm simulated heart rates,good reconstructed image qualities were obtained at most phases,especially at 30%,70%and 80%(all P<0.05).When simulated heart rates were set as 65-75 bpm,the best reconstructing phases included 40%,70%and 80%(all P<0.05),and images obtained in diastolic phase were better.Under 80-95 bpm,the best reconstructing phase was 30%(all P<0.05).When the simulated heart rate reached 100 bpm and above,the reconstructed image qualities were poor at all phases.Conclusion The optimal reconstructed phases were different under different heart rates based on dynamic phantom system simulating the motion of left ventricle and coronary arteries.When the simulated heart rate reached 100 bpm and above,the qualities of reconstructed images were poor under all phases.

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