Assessing water quality in the Pearl River for the last decade based on clustering: Characteristic, evolution and policy implications.

The Pearl River (PR) is China's second-largest river, playing a crucial role in regulating and supplying water in the southeast. However, for the last decade, the PR has been experiencing water quality deterioration due to population growth, rapid economic development, and diverse human activities, particularly in its delta areas. This study analyzed the characteristics and evolution of eight water quality variables, including pH values (pH), water temperature (WT), dissolved oxygen (DO), five-day biochemical oxygen demand (BOD5), permanganate index (PI), total phosphorus (TP), ammonia nitrogen (NH3N), and fluoride (F-), which were monitored monthly at 16 water quality monitoring stations from January 2009 to August 2019. Overall, annual average BOD5 and F- concentrations met Class I water quality standards, while TP and NH3N conformed to lower standards. The cluster results showed noticeable differences for parameter grouping (DO-organic parameters-nutrient and solutes), seasonal variation (wet and dry), and water quality status (contaminated-remediating-fine). The Water Quality Index (WQI) ranged from 8.3 ("very poor") to 91.7 ("excellent") in the entire basin from 2009 to 2019, and NH3N-DO based WQImins were identified using the All-Subsets Linear Regression method. The fitting results of the Generalized Additive Models displayed that the deviance explained by natural factors ranged from 37.2% to 61.3%, while the socioeconomic explanation exceeded 70%. The WQImin component evolution (2003-2019) of Shenzhen River estuary, the most important part of the PR estuary, agreed with key parameter variations in heterogeneous clusters in the entire basin. Moreover, Shenzhen's water quality remediation applications indicated that reasonable-efficient-powerful efforts and support from governments could accelerate recovery. For the management departments, consistent measures should be strictly enforced, and elaborate regionalized management based on clusters could be attempted to maintain excellent water quality.

Remote scoring models of rigidity and postural stability of Parkinson's disease based on indirect motions and a low-cost RGB algorithm.

Background and objectives: The Movement Disorder Society's Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS III) is mostly common used for assessing the motor symptoms of Parkinson's disease (PD). In remote circumstances, vision-based techniques have many strengths over wearable sensors. However, rigidity (item 3.3) and postural stability (item 3.12) in the MDS-UPDRS III cannot be assessed remotely since participants need to be touched by a trained examiner during testing. We developed the four scoring models of rigidity of the neck, rigidity of the lower extremities, rigidity of the upper extremities, and postural stability based on features extracted from other available and touchless motions. Methods: The red, green, and blue (RGB) computer vision algorithm and machine learning were combined with other available motions from the MDS-UPDRS III evaluation. A total of 104 patients with PD were split into a train set (89 individuals) and a test set (15 individuals). The light gradient boosting machine (LightGBM) multiclassification model was trained. Weighted kappa (k), absolute accuracy (ACC ± 0), and Spearman's correlation coefficient (rho) were used to evaluate the performance of model. Results: For model of rigidity of the upper extremities, k = 0.58 (moderate), ACC ± 0 = 0.73, and rho = 0.64 (moderate). For model of rigidity of the lower extremities, k = 0.66 (substantial), ACC ± 0 = 0.70, and rho = 0.76 (strong). For model of rigidity of the neck, k = 0.60 (moderate), ACC ± 0 = 0.73, and rho = 0.60 (moderate). For model of postural stability, k = 0.66 (substantial), ACC ± 0 = 0.73, and rho = 0.68 (moderate). Conclusion: Our study can be meaningful for remote assessments, especially when people have to maintain social distance, e.g., in situations such as the coronavirus disease-2019 (COVID-19) pandemic.

Return to work after injury in Hong Kong: prospective multi-center cohort study.

PURPOSE: Trauma remains a major cause of morbidity and disability worldwide; however, reliable data on the health status of an urban Asian population after injury are scarce. The aim was to evaluate 1-year post-trauma return to work (RTW) status in Hong Kong. METHODS: This was a prospective, multi-center cohort study involving four regional trauma centers from 2017 to 2019 in Hong Kong. Participants included adult patients entered into the trauma registry who were working or seeking employment at the time of injury. The primary outcome was the RTW status up to 1 year. The Extended Glasgow Outcome Scale, 12-item Short Form (SF-12) survey and EQ5D were also obtained during 1-, 3-, 6-, 9-, and 12-month follow-ups. Multivariable Cox proportional hazards regression analysis was used for analysis. RESULTS: Six hundred and seven of the 1115 (54%) recruited patients had RTW during the first year after injury. Lower physical requirements (p = 0.003, HR 1.51) in pre-injury job nature, higher educational levels (p < 0.001, HR 1.95), non-work-related injuries (p < 0.001, HR 1.85), shorter hospital length of stay (p = 0.007, HR 0.98), no requirement for surgery (p = 0.006, HR 1.34), and patients who could be discharged home (p = 0.006, HR 1.43) were associated with RTW within 12 months post-injury. In addition, 1-month outcomes including extended Glasgow Outcome Scale ≥ 6 (p = 0.001, HR 7.34), higher mean SF-12 physical component summary (p = 0.002, HR 1.02) and mental component summary (p < 0.001, HR 1.03), and higher EQ5D health index (p = 0.018, HR 2.14) were strongly associated with RTW. CONCLUSIONS: We have identified factors associated with failure to RTW during the first year following in Hong Kong including socioeconomic factors, injury factors and treatment-related factors and 1-month outcomes. Future studies should focus on the interventions that can impact on RTW outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT03219424.

Identification of ß-Lactams Active against Mycobacterium tuberculosis by a Consortium of Pharmaceutical Companies and Academic Institutions.

Rising antimicrobial resistance challenges our ability to combat bacterial infections. The problem is acute for tuberculosis (TB), the leading cause of death from infection before COVID-19. Here, we developed a framework for multiple pharmaceutical companies to share proprietary information and compounds with multiple laboratories in the academic and government sectors for a broad examination of the ability of ß-lactams to kill Mycobacterium tuberculosis (Mtb). In the TB Drug Accelerator (TBDA), a consortium organized by the Bill & Melinda Gates Foundation, individual pharmaceutical companies collaborate with academic screening laboratories. We developed a higher order consortium within the TBDA in which four pharmaceutical companies (GlaxoSmithKline, Sanofi, MSD, and Lilly) collectively collaborated with screeners at Weill Cornell Medicine, the Infectious Disease Research Institute (IDRI), and the National Institute of Allergy and Infectious Diseases (NIAID), pharmacologists at Rutgers University, and medicinal chemists at the University of North Carolina to screen ∼8900 ß-lactams, predominantly cephalosporins, and characterize active compounds. In a striking contrast to historical expectation, 18% of ß-lactams screened were active against Mtb, many without a ß-lactamase inhibitor. One potent cephaloporin was active in Mtb-infected mice. The steps outlined here can serve as a blueprint for multiparty, intra- and intersector collaboration in the development of anti-infective agents.

Peroxiredoxin alleviates the fitness costs of imidacloprid resistance in an insect pest of rice.

Chemical insecticides have been heavily employed as the most effective measure for control of agricultural and medical pests, but evolution of resistance by pests threatens the sustainability of this approach. Resistance-conferring mutations sometimes impose fitness costs, which may drive subsequent evolution of compensatory modifier mutations alleviating the costs of resistance. However, how modifier mutations evolve and function to overcome the fitness cost of resistance still remains unknown. Here we show that overexpression of P450s not only confers imidacloprid resistance in the brown planthopper, Nilaparvata lugens, the most voracious pest of rice, but also leads to elevated production of reactive oxygen species (ROS) through metabolism of imidacloprid and host plant compounds. The inevitable production of ROS incurs a fitness cost to the pest, which drives the increase or fixation of the compensatory modifier allele T65549 within the promoter region of N. lugens peroxiredoxin (NlPrx) in the pest populations. T65549 allele in turn upregulates the expression of NlPrx and thus increases resistant individuals' ability to clear the cost-incurring ROS of any source. The frequent involvement of P450s in insecticide resistance and their capacity to produce ROS while metabolizing their substrates suggest that peroxiredoxin or other ROS-scavenging genes may be among the common modifier genes for alleviating the fitness cost of insecticide resistance.

Exploration of sources of OVOCs in various atmospheres in southern China.

Oxygenated volatile organic compounds (OVOCs) are critical atmospheric ozone and secondary organic aerosol (SOA) precursors and radical sources, while understanding of OVOC sources in the atmosphere, especially with large anthropogenic emissions, still has large uncertainties. A high-sensitivity proton transfer reaction mass spectrometer (PTR-MS) was deployed in vastly different atmospheres in southern China, including an urban site (SZ-U), a regional site (NA-R), and a background site (NL-B). Four critical OVOCs, i.e., methanol, acetone, methyl ethyl ketone (MEK) and acetaldehyde, five groups of aromatic hydrocarbons, isoprene and acetonitrile were measured with a high time resolution. The featured relative abundance and diurnal variations of the OVOCs indicated that methanol, acetone and MEK had prominent contributions from urban industrial activities, while acetaldehyde was closely related to the photochemical formation at all three sites. The photochemical age-based parameterization method was improved locally and then applied to quantify different sources of daytime OVOCs: anthropogenic secondary and biogenic sources (together 60-73%) were always the dominant source for acetaldehyde in various atmospheres; in addition to a significant background for methanol, acetone and MEK, anthropogenic primary emissions (mostly industrial) were their dominant source at SZ-U (38-73%), while biogenic sources played the key role for them at NL-B (30-43%); biomass burning contributed a small fraction of 5-17% for the four OVOCs at the three sites.

Antimalarial proteasome inhibitor reveals collateral sensitivity from intersubunit interactions and fitness cost of resistance.

We describe noncovalent, reversible asparagine ethylenediamine (AsnEDA) inhibitors of the Plasmodium falciparum proteasome (Pf20S) ß5 subunit that spare all active subunits of human constitutive and immuno-proteasomes. The compounds are active against erythrocytic, sexual, and liver-stage parasites, against parasites resistant to current antimalarials, and against P. falciparum strains from patients in Africa. The ß5 inhibitors synergize with a ß2 inhibitor in vitro and in mice and with artemisinin. P. falciparum selected for resistance to an AsnEDA ß5 inhibitor surprisingly harbored a point mutation in the noncatalytic ß6 subunit. The ß6 mutant was resistant to the species-selective Pf20S ß5 inhibitor but remained sensitive to the species-nonselective ß5 inhibitors bortezomib and carfilzomib. Moreover, resistance to the Pf20S ß5 inhibitor was accompanied by increased sensitivity to a Pf20S ß2 inhibitor. Finally, the ß5 inhibitor-resistant mutant had a fitness cost that was exacerbated by irradiation. Thus, used in combination, multistage-active inhibitors of the Pf20S ß5 and ß2 subunits afford synergistic antimalarial activity with a potential to delay the emergence of resistance to artemisinins and each other.

Does an assessment aid improve Glasgow Coma Scale scoring by helicopter rescuers in Hong Kong: A randomised controlled trial.

BACKGROUND: Glasgow Coma Scale (GCS) is one of the most commonly used patient assessment tools. This study aimed to determine whether an assessment aid can improve the GCS scoring accuracy by helicopter rescuers in Hong Kong. METHODS: In this randomised controlled trial, Air Crewman Officers (ACMOs) of Government Flying Service in Hong Kong were randomised into two groups, with and without assessment aid. The group with the assessment aid was provided a printed copy of the GCS scoring table while watching the patient simulated videos. Ten videos with GCS scores ranging from 3 to 15 were used to test the performance of total GCS (tGCS) and motor component of GCS (mGCS) scoring. RESULTS: 78% (n=25/32) of ACMOs participated in the study. By comparing the groups with and without an assessment aid, there was no significant difference in the accuracy of tGCS score (60% versus 60%; p=0.85) or mGCS score (80% versus 80%; p=0.75). Overall, mGCS has a higher accuracy than tGCS (p<0.001). The accuracy of mGCS was better than tGCS in mild and moderate brain injury scenarios. CONCLUSION: The use of an assessment aid did not improve GCS scoring by helicopter rescuers. The assessing of mGCS was more accurate than tGCS, further supporting the use of mGCS for prehospital conscious level assessment.

Development and validation of a rapid LC-MS/MS method to quantify letrozole in human plasma and its application to therapeutic drug monitoring.

A selective, rapid, and sensitive liquid chromatography-tandem mass spectrometry(LC-MS/MS) method was developed and validated for the determination of letrozole (LTZ) in human plasma, using anastrozole as internal standard (IS). Sample preparation was performed by one-step protein precipitation with methanol. The analyte and IS were chromatographed on a reversed-phase YMC-ODS-C18 column (2.0 × 100 mm i.d., 3 µm) with a flow rate of 0.3 mL/min. The mobile phase consisted of water containing 0.1% formic acid (v/v) and methanol containing 0.1% formic acid (v/v). The mass spectrometer was operated in selected reaction monitoring mode through electrospray ionization ion mode using the transitions of m/z 286.2 → 217.1 for LTZ and m/z 294.1 → 225.1 for IS, respectively. The method was validated for selectivity, linearity, lower limit of quantitation, precision, accuracy, matrix effects and stability in accordance with the US Food and Drug Administration guidelines. Linear calibration curves were 1.0-60.0 ng/mL. Intra- and inter-batch precision (CV) for LTZ were <9.34%, and the accuracy ranged from 97.43 to 105.17%. This method was successfully used for the analysis of samples from patients treated with LTZ in the dose of 2.5 mg/day. It might be suitable for therapeutic drug monitoring of these patients and contribute to predict the risk of adverse reactions.

[Risk assessment of cadmium in rice in Xiangtan, Hunan, China based on Bayesian method]. / 基于贝叶斯方法的湖南湘潭稻米Cdè¶ æ ‡é£Žé™©è¯„ä¼°.

In this study, a total of 73 groups of paddy soil and rice samples were collected from 3 counties of Xiangtan City, Hunan Province, which were Xiangtan, Yuhu, and Xiangxiang, respectively. The total content of Cd in soil and rice samples was determined, the available Cd in soil samples also was measured, and the correlation analysis was conducted among them, respectively. According to the prior probability and data feature, we proposed to use the Bayesian method to eva-luate the risk of Cd content exceeding criterion in rice and construct the risk assessment model. The results indicated that, the average soil Cd content, soil available Cd content and the rice Cd content in the study area were (0.891±0.638) mg·kg-1, (0.791±0.582) mg·kg-1 and (0.376±0.395) mg·kg-1, respectively, and the exceeding standard rate of Cd content in soil and rice reached 89.0% and 52.1%. The rice Cd content was significantly correlated with the available Cd content and total Cd content in soil in Xiangtan and Yuhu. A better correlation was presented between the soil available Cd content and rice Cd content. The rice Cd content in Xiangxiang had no correlation with total Cd content and available Cd content in soil. When the total Cd content and available Cd content were selected as the variables of Bayesian model, the deviations between the predicted exceeding probability of Cd in rice and the true exceeding standard rate were 6.6% and 3.9%, respectively, which proved the Bayesian risk assessment model was reliable. Selecting the available Cd content as the model variable, the predicted result was closer to the true value.

A poor performance in comprehensive geriatric assessment is associated with increased fall risk in elders with hypertension: a cross-sectional study.

BACKGROUND: Fall and serious fall injuries have become a major health concern for elders. Many factors including blood pressure and anti-hypertensive medication application were reported as hazards of fall. The purpose of this study was to determine if age related systemic functional decline related with increased fall risks in elderly patients with hypertension. METHODS: A total of 342 elderly hypertension patients (age 79.5 ± 6.7 years, male 63.8%) were recruited to the study. Comprehensive geriatric assessment (CGA), including measurements about activity of daily living (ADL), nutrition, cognition, depression, numbers of prescription medication and number of clinical diagnosis, was conducted to evaluate the physical and mental status of each participants. Fall risk was evaluated by Morse fall scale, Tinetti performance oriented mobility assessment (POMA) and history of fall in the recent year. Participants were grouped into tertiles according to CGA score. Correlation between CGA and fall risk was analyzed through SPSS 18.0. RESULTS: Participants with higher CGA score were likely to be older, had a lower body mass index (BMI), and a higher prevalence of cardiovascular disease, chronic obstructive pulmonary disease (COPD), cerebrovascular disease and osteoarthropathia. Participants in higher tertile of CGA score got increased prevalence of fall risk than those in lower tertile (P < 0.01 T3 vs. T1, P < 0.01 T3 vs. T2). Correlation analysis and regression analysis showed significant association between CGA and Morse fall scale (P < 0.001), as well as CGA and POMA (P < 0.001). Meanwhile, CGA components also showed co-relationships with increase fall risks. After adjusting age, BMI, benzodiazepine use, cardiovascular disease, cerebrovascular disease, COPD and osteoarthropathia, both history of fall in the recent year and rising Morse fall scale were significantly associated with ADL impairment (OR: 2.748, 95%CI: 1.598-4.725), (OR: 3.310, 95%CI: 1.893-5.788). Decreased Tinetti POMA score was associated with Mini-Mental State Examination (MMSE) (OR: 4.035, 95%CI: 2.100-7.751), ADL (OR: 2.380, 95%CI: 1.357-4.175) and shortened MNA form (MNA-SF) impairment (OR: 2.692, 95%CI: 1.147-6.319). CONCLUSIONS: In elderly adults with hypertension, impaired physical and mental function is associated with increased fall risk. Further study is required to investigate possible mediators for the association and effective interventions.

[Morphological assessment of sulfur mustard-induced acute lung injury in rats through different routes].

OBJECTIVE: To establish an animal model of sulfur mustard (SM)-induced acute lung injury in rats through different routes and compare the morphological changes in lung tissue and cells. METHODS: One hundred and thirty-six male rats were selected and randomly divided into 5 groups, namely peritoneal cavity SM group (n=32), trachea SM group (n=32), peritoneal cavity propylene glycol group (n=32), trachea propylene glycol group (n=32), and normal control group (n=8). The rats in peritoneal cavity SM group were injected intraperitoneally with diluted SM (0.1 ml, 8 mg/kg), and the rats in trachea SM group were injected intratracheally with diluted SM (0.1 ml, 2 mg/kg). Once the rats were sacrificed at 6, 24, 48, and 72 h after SM treatment, morphological changes in lung tissue and cells were observed by light and electron microscopy. RESULTS: In the peritoneal cavity SM group, the epithelial cells of bronchioles maintained intact with increased exudate and bleeding in alveolar cavity and large areas of pulmonary consolidation under the light microscope. In the tracheal SM group, focal ulcer formed in the epithelial cells of bronchioles with increased exudate and bleeding in alveolar cavity, partial pulmonary consolidation, and compensatory emphysema in peripheral alveolar space under the light microscope. The alveolar interval areas were widened obviously in both groups in a time-dependent manner. Under the electron microscope, we observed local loss of cellular membrane in type I alveolar epithelium, broken or lost microvilli in cells of typeⅡalveolar epithelium and fuzzy mitochondrial crista as well as the appearance of ribosome detached from rough endoplasmic reticulum in both two groups. Compared with those in the trachea SM group and the control group, the ratio of the alveolar septum average area to the visual field area in the peritoneal cavity SM group at 6, 24, 48, and 72 h was significantly higher (P<0.05). CONCLUSION: The lung tissue injury through the intraperitoneal route is more severe than that through the tracheal route, while focal ulceration of bronchioles epithelial cells appears in the case of tracheal route. The degree of injury increases over time in both groups, and the cellular damage is approximately the same in both groups.

Total energy expenditure of 16 Chinese young men measured by the doubly labeled water method.

OBJECTIVE: Doubly labeled water (DLW) method is the gold standard for measuring total energy expenditure (TEE). We used this method to measure TEE in Chinese young men. METHODS: Sixteen healthy young men age 23±1 years with body mass index 22.0±1.4 kg/m2 were recruited. TEE was measured by the DLW method, and basal energy expenditure (BEE) was determined by indirect calorimetry. We also conducted 24-h activity, energy balance and factorial approach to estimate energy requirements of the subjects. RESULTS: TEE of subjects by DLW method was 9.45±0.57 MJ/day (2258±180 kcal/day). The 24-h activity was 10.80±0.33 MJ/day (2582±136 kcal/day). The energy requirement, derived from energy balance observations, was 9.93±1.32 MJ/day (2373±315 kcal/day). The BEE of 6.65±0.28 MJ/day (1589±67 kcal/day), calculated by the adjusted Schofield equation, was significantly higher (P<0.001) than that measured by indirect calorimetry, 5.99±0.66 MJ/day (1433±158 kcal/day). The TEE derived from the factorial approach was 10.31±0.43 MJ/day (2463±104 kcal/day). CONCLUSION: The TEE of Chinese young men measured by the DLW method was about 10% lower than the current recommended nutrient intake (RNI), suggesting that the RNI for Chinese men maybe overestimated. Further studies are warranted to determine the value of the estimated energy requirement.

Assessment of coronary stents by 64-slice computed tomography: in-stent lumen visibility and patency.

OBJECTIVE: To assess lumen visibility of coronary stents by 64-slice computed tomography (CT) coronary angiography, and determine the value of 64-slice CT in non-invasive detecting of in-stent restenosis after coronary artery stent implantation. METHODS: Totally, 60 patients (54 males, aged 57.0+/-12.7 years) and 105 stents were investigated by 64-slice CT at a mean interval of 20.0+/-16.6 months after coronary stents implantation. Axial multi-planar reconstruction images of the stents and curved-planar reconstruction images through the median of the stents were reconstructed for evaluating stent image quality on a 5-point scale (1=excellent, 5=non-assessable), and stent lumen diameter was detected. Conventional coronary angiography was performed in 18 patients, and 32 stents were evaluated. RESULTS: Image quality was good to excellent on average (score 1.71+/-0.76). Stent image quality score was correlated to heart rate (r=0.281, P<0.01) and stent diameter (r=-0.480, P<0.001). All the stents were assessable in lumen visibility with an average visible lumen diameter percentage of 60.7%+/-13.6%. Visible lumen diameter percentage was correlated to heart rate (r=-0.193, P<0.05), stent diameter (r=0.403, P<0.001), and stent image quality score (r=-0.500, P<0.001). Visible lumen diameter percentage also varied depending on the stent type. In comparison with the conventional coronary angiography, 4 of 6 in-stent stenoses were correctly detected. The sensitivity and specificity for the detection of in-stent stenosis were 66.7% and 84.6%, respectively. CONCLUSIONS: Using a 64-slice CT, the stent lumen is partly visible in most of the stents. And 64-slice CT may be useful in the assessment of stent patency.

[Assessment of global left ventricular function by 64-slice spiral CT in patients with old myocardial infarction].

OBJECTIVE: To investigate the clinical value of 64-slice spiral CT (64SCT) in assessing global left ventricular function in patients with old myocardial infarction (OMI), with magnetic resonance imaging (MRI) as the reference standard. METHODS: A total of 28 patients (23 men and 5 women) with OMI underwent contrast-enhanced 64SCT with retrospective electrocardiographic-gating, MRI, and transthoracic echocardiography (Echo). The data sets of 64SCT and MRI were reconstructed at both end-diastole and end-systole to measure left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejective fraction (EF), and myocardial mass at end-diastole (MM). The data acquired with 64SCT and Echo were compared with the results obtained on MRI as the standard of reference respectively. RESULTS: The parameters of global left ventricular function obtained with 64SCT were significantly correlated with the MRI data (r = 0.788-0.976, P < 0.001). EDV, ESV, SV, EF, and MM were slightly overestimated by 64SCT compared with MRI; however, there was no significant difference among the measurements. 64SCT was in good agreement with MRI. For the EDV, ESV, SV, and EF, the limits of agreement with Echo were significantly larger than with 64SCT compared with MRI (P < 0.05). The sensitivity, specificity, and accuracy of 64SCT to identify EF value less than 50% were 84.6%, 100% and 92.9%, respectively, whereas those of Echo were 61.5%, 66.7% and 64.3%, respectively. The accuracy of 64SCT was significantly higher than that of Echo (P < 0.01). There was a significantly larger overestimation of EDV, ESV, and SV with Echo than with 64SCT compared with MRI (P < 0.05), whereas EF was not significantly different. CONCLUSIONS: A strong correlation between 64SCT and MRI is found for all parameters. 64SCT agrees well with MRI, and allows more reliable and accurate evaluation of global left ventricular function in patients with OMI than Echo compared with MRI.

[Assessment of coronary stent lumen visibility and patency by 64-slice spiral CT angiography].

OBJECTIVE: To evaluate the clinical value of assessment of coronary stent patency by 64-slice spiral CT coronary angiography. METHODS: Totally 29 patients (59 stents) were investigated using a retrospective ECG-gated enhanced scan by 64-slice spiral CT at a mean interval of (28.4 +/- 21.2) months after coronary stent implantation. Axial multi-planar reconstruction (MPR) of the stents and curved-planar reconstruction (CPR) through the stents were evaluated for image quality on a 5-point scale (1 = excellent, 5 = uninterpretable) and lumen diameter. Stent lumen diameter was compared with the vessel diameter proximal of the stents to assess the in-stent lumen visibility. Conventional coronary angiography was performed in 5 patients, and 9 stents were evaluated. RESULTS: The image quality was good to excellent on average (scores: 1.94 +/- 0.84), depending on heart rate, breath movement, and stent location. Stent lumen was visible, on average a percentage off (76.1 +/- 11.1)% of the lumen diameter. All the 9 stents were correctly detected as being patent, which was confirmed by conventional coronary angiography. CONCLUSION: 64-slice spiral CT is a useful tool to assess the coronary stent patency.

[Assessment of global left ventricular function with multi-slice spiral computed tomography].

OBJECTIVE: To investigate the value of multi-slice spiral computed tomography (MSCT) in the determination of global left ventricular function. METHODS: Twenty-nine patients with confirmed or suspected coronary heart diseases were imaged with a contrast-enhanced retrospective electrocardiogram (ECG) -gated technique on a 64-slice spiral CT scanner. The data sets were reconstructed at both end-diastolic and end-systolic phases in order to measure left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular stroke volume (LVSV), and left ventricular ejection fraction (LVEF). The results were compared with corresponding values obtained from conventional left ventriculography (LVG). RESULTS: LVEDV, LVESV, LVSV, and LVEF obtained with 64-slice spiral CT were significantly correlated with the LVG data (r = 0. 887-0.956, P < 0.001). According to the Bland-Altman approach, the mean differences for LVEDV, LVESV, LVSV, and LVEF were -2.3 ml, 4.1 ml, -6.4 ml, and - 3.5%, respectively. The limits of agreement for LVEDV, LVESV, LVSV, and LVEF were -27.2-22.4 ml, -10.2-18.4 ml, -26.4-13.6 ml, and -9.8%-3.0%, respectively. CONCLUSION: MSCT has clinically acceptable agreement with LVG for the quantification of global left ventricular function.

Assessment of myocardial viability with contrast-enhanced magnetic resonance imaging and comparison with single-photon emission computed tomography.

OBJECTIVE: To compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease. METHODS: Twenty patients with suspected chronic ischemic heart disease underwent ceMRI and technetium-99m sestamibi single-photon emission computed tomography (SPECT). Patients with positive SPECT results also underwent 18F-fluorodeoxyglucose (FDG) SPECT. In a 17-segment model, the segmental extent of hyperenhancement (SEH) by ceMRI was compared with segmental FDG and sestamibi uptake by SPECT. Correlation between the extent of hyperenhancement by ceMRI and left ventricular function was analyzed. RESULTS: Seven patients got negative results both in ceMRI and technetium-99m sestamibi SPECT. The rest 13 patients with positive results then underwent 18F-FDG SPECT. In 221 segments of 13 patients, SEH was (2.1 +/- 8.2)%, (25.0 +/- 13.7)%, and (57.7 +/- 23.6)% in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively, and there were significant differences between either two of them (all P < 0.05). By receiver operating characteristic curve analysis, the area under the curve was 0.95 for the differentiation between viable and non-viable segments. At the cutoff value of 34%, SEH optimally differentiated viable from non-viable segments defined by SPECT. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by SPECT were 92% and 93%, respectively. Hyperenhancement size by ceMRI was correlated negatively with the left ventricular ejection fraction (r = - 0.90, P < 0.01) and positively with left ventricular volumes (r = 0.62 for end-diastolic volume, r = 0.75 for end-systolic volume, both P < 0.05). CONCLUSION: CeMRI allows assessment of myocardial viability with a high accuracy in patients with chronic ischemic heart disease.