Biomedical subjects

François Laurent

Publications and source records attributed to François Laurent.

At least 19 recordsLinked to original sources

PubMed2007

Air trapping in mild and moderate asthma: effect of inhaled corticosteroids.

BACKGROUND: Air trapping reflects small airway obstruction in asthma and can be assessed quantitatively by high-resolution computed tomography (HRCT). Hydrofluoroalkane-beclomethasone dipropionate (HFA-BDP) is deposited across all sizes of airways, including the small ones. However, its long-term effect on air trapping remains unknown in uncontrolled asthma. OBJECTIVES: To compare the effect of inhaled corticosteroids of different particle size - HFA-BDP and fluticasone propionate (FP) - on lung attenuation in mild-to-moderate uncontrolled asthma. METHODS: A randomized study was performed to analyze the effect of HFA-BDP (400 microg/d) or FP (500 microg/d) given over a period of 3 months to patients with uncontrolled mild-to-moderate asthma. HRCT was performed with spirometric gating, and lung attenuation was measured at residual volume and at pulmonary total capacity. The difference between inspiratory and expiratory attenuation was calculated as an air trapping index. RESULTS: Twenty-five out of 58 patients had abnormal air trapping and could be included in the study. Lung attenuation significantly diminished in the posterior zones of the lung after a 3-month treatment with HFA-BDP or FP, but the difference between the groups was not significant. Adjusted mean variations of the air trapping index from baseline to treatment completion were 34.3 (11.2, 57.3) and 27.3 (6.4, 48.2) for the HFA-BDP and FP groups, respectively. However, the reduction of air trapping area was more pronounced in the group treated with HFA-BDP. CONCLUSION: Inhaled corticosteroids decrease air trapping in uncontrolled asthma regardless of their particle size. CLINICAL IMPLICATIONS: In mild-to-moderate asthma, air trapping assessed by HRCT may be a new outcome related to the control of the disease.

Administration, Inhalation↗

PubMed2006

Assessment of airways with three-dimensional quantitative thin-section CT: in vitro and in vivo validation.

PURPOSE: To prospectively validate the ability of customized three-dimensional (3D) software to enable bronchial tree skeletonization, orthogonal reconstruction of the main bronchial axis, and measurement of cross-sectional wall area (WA) and lumen area (LA) of any visible bronchus on thin-section computed tomographic (CT) images. MATERIALS AND METHODS: Institutional review board approval and patient agreement and informed consent were obtained. Software was validated in a phantom that consisted of seven tubes and an excised human lung obtained and used according to institutional guidelines. In vivo validation was performed with multi-detector row CT in six healthy subjects (mean age, 47 years; range, 20-55 years). Intra- and interobserver agreement and reproducibility over time for bronchial tree skeletonization were evaluated with Bland-Altman analysis. Concordance in identifying bronchial generation was assessed with the kappa statistic. WA and LA obtained with the manual method were compared with WA and LA obtained with validated software by means of the Wilcoxon test and Bland-Altman analysis. RESULTS: WA and LA measurements in the phantom were reproducible over multiple sessions (P > .90) and were not significantly different from WA and LA assessed with the manual method (P > .62). WA and LA measurements in the excised lung and the subjects were not different from measurements obtained with the manual method (intraclass correlation coefficient > 0.99). All lobar bronchi and 80.8% of third generation bronchi, 72.5% of fourth generation bronchi, and 37.7% of fifth generation bronchi were identified in vivo. Intra- and interobserver agreement and reproducibility over time for airway skeletonization and concordance in identifying bronchial generation were good to excellent (intraclass correlation coefficient > 0.98, kappa > 0.54, respectively). CONCLUSION: This method enables accurate and reproducible measurement of WA and LA on reformatted CT sections perpendicular to the main axis of bronchi visible on thin-section CT scans.

Adult↗

PubMed2006

Bronchial measurement with three-dimensional quantitative thin-section CT in patients with cystic fibrosis.

PURPOSE: To prospectively compare bronchial measurements obtained with three-dimensional quantitative thin-section computed tomography (CT) with those obtained with thin-section CT scores in the assessment of the severity of pulmonary cystic fibrosis (CF). MATERIALS AND METHODS: Ethics committee approval was obtained. Sixteen patients with CF (mean age, 26.6 years; range, 18-42 years) and five healthy volunteers (mean age, 27.4 years; range, 21-44 years) gave written informed consent, underwent multi-detector row CT and a pulmonary function test (PFT), and were divided into three groups: group A, healthy volunteers; group B, patients with mild CF (forced expiratory volume in 1 second [FEV(1)] > 80%); and group C, patients with severe CF (FEV(1) < 80%). Two observers obtained thin-section CT scores with eight scoring systems. Bronchial cross-sectional wall area (WA), lumen area (LA), airway area, and wall thickness (WT) were measured with customized software and were normalized on the basis of subject body surface. Morphologic characteristics, PFT results, thin-section CT scores, and quantitative measurements were compared among the three groups with analysis of variance. Correlations among bronchial measurements, PFT results, and CT scores were calculated with the Spearman correlation coefficient. RESULTS: Thin-section CT scores were different between group C and either group A or group B (P < .05). WA and WT were significantly different among all groups (P < .05). Interscore correlations and correlations between bronchial parameters and scores were high (r > 0.89, P < .0001). Scores, WA, and WT were significantly correlated with PFT obstructive indexes (P < .047). CONCLUSION: WA and WT assessed with dedicated software on multi-detector row CT images allow evaluation of the severity of pulmonary CF.

Adolescent↗

PubMed2006

Pulmonary arteriovenous malformation treated with embolotherapy: systemic collateral supply at multidetector CT angiography after 2-20-year follow-up.

PURPOSE: To retrospectively evaluate frequency of systemic arterial collateral supply to treated pulmonary arteriovenous malformations (PAVMs) in long-term follow-up with multi-detector row helical computed tomography (CT). MATERIALS AND METHODS: Institutional review board approval was obtained, with waiver of informed consent. Thirty-two patients (19 male, 13 female; mean age, 43 years) underwent follow-up multi-detector row helical CT angiography of the chest (collimation, 16x0.75 mm) 2 or more years after embolotherapy of PAVMs. The study group had a history of successful embolotherapy of 53 PAVMs and a mean of 9 years of follow-up (range, 2-20 years). A search for abnormal systemic arteries was based on analysis of thin-collimated contiguous transverse CT scans and two- and three-dimensional images including maximum intensity projections and volume-rendered images. Statistical comparison was performed with the Fisher exact test (categoric variables) and Wilcoxon rank sum test (continuous variables). RESULTS: At CT, 13 patients (group 1) had abnormally enlarged systemic arteries and 19 patients (group 2) had no abnormal arteries. In group 1, 32 abnormally enlarged arteries were seen-five bronchial and 27 nonbronchial arteries (14 inferior phrenic, six musculophrenic, five internal mammary, two intercostal). The degree of enlargement was moderate for 26 arteries and marked for six. There were no significant differences between groups for (a) clinical characteristics of patients, including history of surgery before or after embolotherapy (P=.7); (b) anatomic structures of treated PAVMs; and (c) embolization procedures and their effectiveness. The number of patients with features suggestive of lung infarction in the days or months after embolotherapy was significantly higher in group 1 (P=.04). On CT angiograms, the number of patients with features suggestive of sequelae of lung infarction was significantly higher in group 1 (P=.02). There were no symptomatic differences attributable to systemic collateral supply between groups; in particular, there was no hemoptysis in group 1. CONCLUSION: Abnormally enlarged systemic arteries were present in 13 of 32 patients, in whom there was a significantly higher frequency of clinical and/or radiographic features suggestive of lung infarction after embolotherapy.

Adult↗

PubMed2006

Predictive value of noninvasive coronary angiography with multidetector computed tomography to detect significant coronary stenosis before valve surgery.

Quantitative coronary angiography (QCA) is routinely performed before valve surgery for severe acquired valvular disease. This technique is relatively invasive, especially in a population with an average risk for significant coronary stenosis. Multidetector computed tomography (MDCT) coronary angiography allows the noninvasive evaluation of the coronary anatomy. The aim of this prospective study was to evaluate the predictive values of 16-slice MDCT in the detection of significant coronary stenosis (> or = 50%) before valve surgery in patients with severe valvular disease without known coronary artery disease and average risk, in comparison with conventional QCA. Forty patients with severe acquired valvular disease (mean age 70 +/- 8.6 years; 20 women; 27 with severe aortic stenosis) underwent coronary MDCT 2 days before cardiac catheterization with QCA. The mean heart rate was 64.7 +/- 8.8 beats/min (range 41 to 78). Four hundred fifty-eight of 600 coronary artery segments (77.3%) were considered assessable by MDCT. In a per-segment analysis, the sensitivity of MDCT for the detection of significant coronary lesions > or = 50% was 77.7%, the specificity was 98%, the positive predictive value was 42.4%, and the negative predictive value was 99%. The main cause of false-positive or false-negative results or nonassessable evaluations was severe coronary calcification. In a per-patient analysis, in comparison with QCA, MDCT correctly classified 33 of 40 patients (82.5%). In conclusion, in patients with an average risk for coronary stenosis before valve surgery, MDCT coronary angiography detected significant obstructive coronary artery disease, with a 99% NPV.

Aged↗

PubMed2006

In vivo MR imaging of pulmonary arteries of normal and experimental emboli in small animals.

PURPOSE: To demonstrate the feasibility of pulmonary MRA in living rodents. MATERIALS AND METHODS: A three-dimensional (3D) gradient echo sequence was adapted to perform a time-of-flight (TOF) angiography of rat lung. Angiogram with a spatial resolution of 195 x 228 x 228 microm(3) was acquired in around 33 minutes. The method was then applied in animals before and after pulmonary embolism (PE) induction. Section of the proximal right pulmonary artery was measured and compared between the two populations. RESULTS: Good quality images were obtained with a contrast-to-noise ratio (CNR) of 9 +/- 3 in the proximal part of the pulmonary artery. Cross-section areas of the right main artery are statistically different before (3.45 +/- 0.69 mm(2)) and after induction of PE (4.3 +/- 0.86 mm(2)). CONCLUSION: This noninvasive tool permits angiogram acquisition at around 200 microm spatial resolution and objective distinction between healthy and embolized arteries.

Animals↗

PubMed2006

Metabolism of [14C]-2,4-dichlorophenol in edible plants.

Several 2,4-dichlorophenoxyacetic acid (2,4-D)-sensitive plants have been modified by genetic engineering with tfdA gene to acquire 2,4-D tolerance. The expression product of this gene degrades 2,4-D to 2,4-dichlorophenol (DCP), which is less phytotoxic but could cause a problem of food safety. After a comparison of 2,4-D and DCP metabolism in transgenic 2,4-D-tolerant and wild cotton (Gossypium hirsutum L.), a direct study of DCP metabolism in edible plants was performed. After petiolar uptake of a [U-phenyl-(14)C]-DCP solution followed by a 48 h water chase, aqueous extracts were analysed by high-performance liquid chromatography. Metabolites were thereafter isolated and their structural identities were determined by enzymatic and chemical hydrolyses and mass spectrometry analyses. The metabolic fate of DCP was equivalent to 2,4-D metabolism in transgenic 2,4-D-tolerant cotton. In addition, DCP metabolism was similar in transgenic and wild cotton. The major terminal metabolites were DCP-saccharide conjugates in all species, essentially DCP-(6-O-malonyl)-glucoside or its precursor DCP-glucose. The significance of this metabolic pathway with regard to food safety is discussed.

2,4-Dichlorophenoxyacetic Acid↗

PubMed2006

CT and MRI of Lung Cancer.

Computed tomography (CT) is still the cornerstone of imaging studies in the preoperative staging and post- therapeutic evaluation of lung cancer. The most recent developments in multidetector technology have dramatically improved the temporal and spatial resolution of CT. In the mean time, magnetic resonance imaging (MRI) has not become a routine examination in lung imaging and is today only used as a problem-solving tool in patients in whom CT remains equivocal. This article will describe the current tools developed in the multidetector CT era for evaluating the lung, and state-of-the-art MR examination of the chest. Then, the role of CT and MRI in nodule detection, the distinction between benign and malignant nodules, and the benefit of CT and MRI in the staging and post-therapeutic evaluation of lung cancer will be covered.

Continuity of Patient Care↗

PubMed2005

Quantitative MRI comparison of pulmonary hemodynamics in mustard/senning-repaired patients suffering from transposition of the great arteries and healthy volunteers at rest.

In Mustard/Senning-repaired (MSR) patients, the right and left ventricles (RV, LV) act as the systemic and pulmonary ventricle, respectively. The purpose of the study was to compare non-invasively, at rest, pulmonary ventricle systolic function and hemodynamics in MSR patients with those of healthy volunteers. Velocity-encoded MR imaging was performed at the level of the main pulmonary artery (MPA) in ten male patients late after a Mustard/Senning correction performed early in infancy and in ten male volunteers. Both blood flow and MPA cross-sectional area variations were recorded over a complete cardiac cycle. MPA distensibility, body surface area (BSA)-normalized pulmonary ventricle systolic power and work were significantly lower in the MSR patients compared to volunteers. In particular, BSA-normalized LV systolic power and work in MSR patients were equal to 82 and 77% on average of those of the RV in volunteers (0.32 vs. 0.39 W/m2 and 0.10 vs. 0.13 J/m2), respectively. We conclude that in MSR patients at rest two unrelated findings were observed: (1) a reduced MPA distensibility and (2) a significantly lower systolic mechanical performance of the pulmonary LV compared to that of the RV in healthy volunteers. The latter quantification indirectly confirms the lowest systemic RV systolic mechanical performance previously published.

Adult↗

PubMed2005

High-dose acetylcysteine in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis is a chronic progressive disorder with a poor prognosis. METHODS: We conducted a double-blind, randomized, placebo-controlled multicenter study that assessed the effectiveness over one year of a high oral dose of acetylcysteine (600 mg three times daily) added to standard therapy with prednisone plus azathioprine. The primary end points were changes between baseline and month 12 in vital capacity and in single-breath carbon monoxide diffusing capacity (DL(CO)). RESULTS: A total of 182 patients were randomly assigned to treatment (92 to acetylcysteine and 90 to placebo). Of these patients, 155 (80 assigned to acetylcysteine and 75 to placebo) had usual interstitial pneumonia, as confirmed by high-resolution computed tomography and histologic findings reviewed by expert committees, and did not withdraw consent before the start of treatment. Fifty-seven of the 80 patients taking acetylcysteine (71 percent) and 51 of the 75 patients taking placebo (68 percent) completed one year of treatment. Acetylcysteine slowed the deterioration of vital capacity and DL(CO): at 12 months, the absolute differences in the change from baseline between patients taking acetylcysteine and those taking placebo were 0.18 liter (95 percent confidence interval, 0.03 to 0.32), or a relative difference of 9 percent, for vital capacity (P=0.02), and 0.75 mmol per minute per kilopascal (95 percent confidence interval, 0.27 to 1.23), or 24 percent, for DL(CO) (P=0.003). Mortality during the study was 9 percent among patients taking acetylcysteine and 11 percent among those taking placebo (P=0.69). There were no significant differences in the type or severity of adverse events between patients taking acetylcysteine and those taking placebo, except for a significantly lower rate of myelotoxic effects in the group taking acetylcysteine (P=0.03). CONCLUSIONS: Therapy with acetylcysteine at a dose of 600 mg three times daily, added to prednisone and azathioprine, preserves vital capacity and DL(CO) in patients with idiopathic pulmonary fibrosis better than does standard therapy alone.

Acetylcysteine↗

PubMed2005

Airway wall thickness in cigarette smokers: quantitative thin-section CT assessment.

PURPOSE: To design and validate a dedicated software tool to measure airway dimensions on thin-section computed tomographic (CT) images and to use the tool to prospectively compare airway wall thickness in nonsmokers with normal lung function with that in smokers with and without chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: All subjects gave written informed consent. The study was approved by local ethics committee. With Laplacian of Gaussian algorithm, software was tested in phantom and excised sheep lung fixed in inflation and validated with Bland-Altman analysis. Study prospectively included nine nonsmokers (six women, three men; mean age, 53 years +/- 5.6 [standard error of the mean]) with normal lung function (group 1), seven smokers (three women, four men; mean age, 56 years +/- 5.6) with normal lung function (group 2), and eight smokers (zero women, eight men; mean age, 65 years +/- 4.0) with COPD. Calculations were determined with spirometrically gated CT: For each selected bronchus, the wall area (WA), internal area (IA), airway caliber (sum of IA and WA), and WA/IA ratio were calculated. For each patient, summation of WA to summation of IA (SigmaWA/SigmaIA) ratio, which reflected normalized airway wall thickness, was calculated. Groups were compared by using analysis of variance with generalized linear model and unpaired t test. Pearson correlation coefficient was used to assess correlation between software measurements and pulmonary function test results. RESULTS: Comparison of measurements in phantom and excised sheep lung with algorithm measurements revealed that the latter were reliable and repeatable. In clinical study, SigmaWA/SigmaIA ratio was significantly different among three groups (P < .001). Normalized airway wall thickness and IA were significantly related to lung function test data, including forced expiratory volume in 1 second (r = -0.54, P = .006), specific airway conductance (r = -0.45, P = .03), and forced expiratory flow between 25% and 75% of vital capacity (r = -0.65, P < .001). CONCLUSION: This software provides accurate and reproducible measurements of IA and WA of bronchi on thin-section CT images and demonstrates that in vivo normalized airway wall thickness was larger in smokers with COPD than it was in smokers or nonsmokers without COPD.

Animals↗

PubMed2005

Differential transfer of organic micropollutants through intestinal barrier using Caco-2 cell line.

Food seems to be one of the main ways of animal and human contamination with polycyclic aromatic hydrocarbons (PAHs) and dioxins. In vivo studies showed a blood absorption of these xenobiotics after their ingestion. Our work aimed at studying the in vitro transfer of PAHs and dioxins through intestinal barrier. Caco-2 cells were cultivated on permeable filters to measure transepithelial permeability of (14)C labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin, benzo[a]pyrene, pyrene, and phenanthrene, which differed in their physicochemical properties. The results showed that the molecules were able to cross intestinal cell layers. All the molecules were detected associated with cells, even if the dioxin was the less uptaken compound. Phenanthrene appeared in basal media faster, and its level after a 6-h exposure was respectively 1.1, 2, and 7 times higher than pyrene, benzo[a]pyrene, and 2,3,7,8-tetrachlorodibenzo-p-dioxin levels. These findings suggest that intestinal epithelium plays a key role in selective permeability and then in bioavailibility of micropollutants.

Biological Transport↗

PubMed2005

Enantioselective metabolism of (R)- and (S)-4-hydroxy-2-nonenal in rat.

4-Hydroxy-2-nonenal (HNE) is an endogenous product of lipid peroxidation, which is believed to play a biological role in the pathogenesis of various diseases. HNE is formed as a racemic mixture of (R)- and (S)- enantiomers. These enantiomers differ in their biological properties. The aim of this study was to investigate separately the in vivo metabolism of the two HNE enantiomers in male rats after intravenous administration of the corresponding radiolabeled compounds and to compare the results with those obtained with the racemic mixture. Although the difference in the excretion rates was not statistically significant, the HPLC profiles of urinary metabolites showed qualitative and quantitative differences between the two enantiomers. The level of 3-mercapturic acid-1,4-dihydroxynonane, which is considered as the major urinary metabolite of HNE, was significantly lower in the case of (S)-HNE injected rats. In vitro studies using rat liver cytosolic incubations and HNE-glutathione conjugate as substrate were performed to clarify the intermediate pathways involved in their metabolism. Large differences were obtained in the reduction and retro-Michael conversion steps of the metabolism between the conjugates originating from the two enantiomers.

Acetylcysteine↗

PubMed2005

Feasibility of aortic pulse pressure and pressure wave velocity MRI measurement in young adults.

PURPOSE: To investigate the feasibility of assessing, noninvasively, aortic pulse pressure (APP) and pulse wave velocity (PWV) in the ascending aorta of young adults by means of velocity-encoded magnetic resonance (MR) imaging. MATERIALS AND METHODS: In a series of 11 healthy volunteers, velocity-encoded MR imaging provided pairs of magnitude and phase-contrast images. Blood flow velocity and aortic cross-sectional area (CSA) were determined with a 30-msec temporal resolution. A model analysis revealed that variation in aortic CSA and in maximal blood flow velocity throughout systole could be used to estimate APP and, hence, to derive PWV by means of two different methods. RESULTS: Mean +/- SD values of the APP for the series were 54.2 +/- 16.4 mmHg (range 32.2-84.1 mmHg). The ascending aortic PWV mean +/- SD values were 5.03 +/- 1.10 m/second and 5.37 +/- 1.23 m/second according to the two methods, and both estimates were not significantly different (95% confidence level). CONCLUSION: These results are in agreement with previously published data, suggesting that APP and PWV can be determined, noninvasively, in young adults using MRI.

Adult↗

PubMed2004

Factors influencing accuracy of CT-guided percutaneous biopsies of pulmonary lesions.

The purpose of this study was to evaluate the performance and complication rate of CT-guided percutaneous lung biopsy of pulmonary lesions using a coaxial automated biopsy device and to determine factors influencing the false negative rate for the diagnosis of malignancy. A prospective study of 605 consecutive biopsies performed in 595 patients was undertaken. The performances for the diagnosis of malignancy, for the specific diagnosis of benignity and the complication rate were calculated. Patients' characteristics and lesion and procedure variables were included in a logistic regression model and analyzed as potential predictive variables for occurrence of a false-negative diagnosis of malignancy. The sensitivity, specificity, positive predictive value and negative predictive value for a diagnosis of malignancy were 92.2, 99.1, 99.8 and 73.3%, respectively. A specific diagnosis of benignity was obtained in 43 cases (40%) biopsies. The pneumothorax rate was 17.4% (n = 105) with 3 (0.5%) requiring drainage. At multivariate analysis, the sole variable significantly associated with a higher rate of false negative diagnosis of malignancy was lesion size equal to or smaller than 10 mm in diameter. Using a coaxial automated device, CT-guided percutaneous biopsy of pulmonary lesions of size equal to or less than 10 mm in diameter provides a high diagnostic yield with an acceptable complication rate.

Adult↗

PubMed2004

Serial chest CT findings in interstitial lung disease associated with polymyositis-dermatomyositis.

OBJECTIVE: A retrospective study was carried out in two institutions to determine serial changes in the pattern, distribution, and extent of interstitial lung disease (ILD) associated with polymyositis (PM)-dermatomyositis (DM) using HRCT. SUBJECTS AND METHODS: Twenty patients with PM-DM and clinical suspicion of ILD who underwent at least two serial HRCT examinations were retrospectively evaluated by two readers. Patients were classified according to the dominant CT pattern which was correlated with clinical evolution and underlying histology when available (n=6). RESULTS: Patients were classified into four groups according to the dominant pattern: ground-glass attenuation and reticulation (group 1, n=9); honeycombing (group 2, n=4); airspace consolidation (group 3, n=4), and normal or almost normal lung (group 4, n=3). Under medical treatment, serial HRCT showed that the extent of areas of ground-glass opacities (group 1) decreased in five patients, stabilized in two, and increased in two. Pathologic findings demonstrated usual interstitial pneumonia (UIP) in two cases and unspecified interstitial pneumonia in one. In group 2, extent of honeycombing increased in three cases and stabilized in one. In group 3, dramatic resolution of airspace consolidation occurred in three cases. Clinical deterioration with extensive consolidation at CT and diffuse alveolar damage (DAD) at histology occurred in one patient of each of the three previous groups. Lesions stayed invisible or progressed slightly in the fourth group. CONCLUSION: In ILD associated with PM-DM, clinical deterioration and DAD in the follow-up can be observed whatever the HRCT pattern. However, unfavorable evolution is constant when honeycombing is present at the initial CT.

Adult↗

PubMed2003

Quantitative MRI comparison of systemic hemodynamics in Mustard/Senning repaired patients and healthy volunteers at rest.

The purpose of the present study was to non-invasively compare ascending aortic blood flow and cross-sectional area (CSA) variations vs time in Mustard or Senning repaired (MSR) patients against those of healthy volunteers at rest. Velocity-encoded MR imaging was performed in 10 male patients (age range 18-24 years, median age 20.5 years) late after a Mustard or Senning correction, and in 10 male healthy volunteers (age range 21-25 years, median age 22.5 years), at the upper part of the ascending aorta. Both aortic cross-sectional area (CSA) and blood-flow variations were recorded over a complete cardiac cycle, with a 30-ms time of resolution. The body-surface area (BSA), the mean CSA over the systolic phase, and the BSA-normalized systemic ventricle power and work were significantly lower in the patient series compared with those of the volunteer series. The BSA-normalized right ventricle (RV) power and work of MSR patients were equal to 87 and 83% on average of those of the left ventricle (LV) of healthy volunteers. We conclude that, at rest, the mechanical performance of the systemic RV in MSR patients is significantly lower than that of the LV in healthy volunteers. Furthermore, the significantly lower aortic CSA found in MSR patients than in healthy volunteers may reveal an increase in the vasomotor tone.

Adolescent↗

PubMed2003

A computed method for noninvasive MRI assessment of pulmonary arterial hypertension.

The present method enables the noninvasive assessment of mean pulmonary arterial pressure from magnetic resonance phase mapping by computing both physical and biophysical parameters. The physical parameters include the mean blood flow velocity over the cross-sectional area of the main pulmonary artery (MPA) at the systolic peak and the maximal systolic MPA cross-sectional area value, whereas the biophysical parameters are related to each patient, such as height, weight, and heart rate. These parameters have been measured in a series of 31 patients undergoing right-side heart catheterization, and the computed mean pulmonary arterial pressure value (Ppa(Comp)) has been compared with the mean pressure value obtained from catheterization (Ppa(Cat)) in each patient. A significant correlation was found that did not differ from the identity line Ppa(Comp) = Ppa(Cat) (r = 0.92). The mean and maximal absolute differences between Ppa(Comp) and Ppa(Cat) were 5.4 and 11.9 mmHg, respectively. The method was also applied to compute the MPA systolic and diastolic pressures in the same patient series. We conclude that this computed method, which combines physical (whoever the patient) and biophysical parameters (related to each patient), improves the accuracy of MRI to noninvasively estimate pulmonary arterial pressures.

Adult↗