Biomedical subjects

Alain Duhamel

Publications and source records attributed to Alain Duhamel.

35 records · Page 2Linked to original sources

PubMed2005

Tools for statistical analysis with missing data: application to a large medical database.

Missing data is a common feature of large data sets in general and medical data sets in particular. Depending on the goal of statistical analysis, various techniques can be used to tackle this problem. Imputation methods consist in substituting the missing values with plausible or predicted values so that the completed data can then be analysed with any chosen data mining procedure. In this work, we study imputation in the context of multivariate data and we evaluate a number of methods which can be used by today's standard statistical software packages. Imputation using multivariate classification, multiple imputation and imputation by factorial analysis are compared using simulated data and a large medical database (from the diabetes field) with numerous missing values. Our main result is to provide a control chart for assessing data quality after the imputation process. To this end, we developed an algorithm for which the input is a set of parameters describing the underlying data (e.g., covariance matrix, distribution) and the output is a chart which plots the change in the prediction error with respect to the proportion of missing values. The chart is built by means of an iterative algorithm involving four steps: (1) a sample of simulated data is drawn by using the input parameters; (2) missing values are randomly generated; (3) an imputation method is used to fill in the missing data and (4) the prediction error is computed. Steps 1 to 4 are repeated in order to estimate the distribution of the prediction error. The control chart was established for the 3 imputation methods studied here, assuming a multivariate normal distribution of data. The use of this tool on a large medical database was then investigated. We show how the control chart can be used to assess the quality of the imputation process in the pre-processing step upstream of data mining procedures.

Algorithms↗

PubMed2004

Coronary arteries: assessment of image quality and optimal reconstruction window in retrospective ECG-gated multislice CT at 375-ms gantry rotation time.

Our objective was to evaluate the image quality of a 16-slice CT system with a rotation time of 375 ms in the assessment of coronary arteries. One hundred patients underwent iodine-enhanced CT coronary angiography within a single breath hold. Images were reconstructed in diastole, 300, 350, 400, 450, 500 and 550 ms prior to the onset of the next R-wave using absolute reverse retrospective ECG gating. The 15 coronary segments of the AHA classification were consensually reviewed by two radiologists. On the whole, best quality imaging was obtained with reconstruction intervals of -350 ms and -400 ms in high percentages of each segment (P<0.0001). Only 6.2% of the arteries with a diameter greater than or equal to 1.5 mm were not assessable because of extensive calcifications (3.9%), cardiac motion artifacts (1.9%), lack of enhancement (0.2%) and stent artifacts (0.3%). In patients with a heart rate above 70 beats per minute, the percentage of assessable segments decreased to 88%, while at a lower heart rate it increased to 95%. In 61% of the patients, all segments were assessable. In conclusion, this generation of CT technique may allow visualization of coronary arteries with a low percentage of non-assessable segments.

Adult↗

PubMed2004

Cumulative influence of organ dysfunctions and septic state on mortality of critically ill children.

The interaction between sepsis and multiple organ dysfunction syndrome is poorly defined in children. We analyzed by Cox regression models the cumulative influence of organ dysfunctions, using the pediatric logistic organ dysfunction (PELOD) score, and septic state (systemic inflammatory response syndrome or sepsis, severe sepsis, and septic shock) on mortality of critically ill children. We included 593 children (mortality rate: 8.6%) from three pediatric intensive care units; 514 patients had at least a systemic inflammatory response syndrome and 269 had two or more organ dysfunctions. Hazard ratio of death significantly increased with the severity of organ dysfunction, as estimated by the PELOD score, and the worst diagnostic category of septic state. Each increase of one unit in the PELOD score multiplied the hazard ratio by 1.096 (p < 0.0001); hazard ratio of diagnostic category was 9.039 (p = 0.031) for systemic inflammatory response syndrome or sepsis, 18.797 (p = 0.007) for severe sepsis and 32.572 (p < 0.001) for septic shock. Cumulative hazard ratio of death = (hazard ratio of PELOD score) x (hazard ratio of diagnostic category). We conclude that there is a cumulative accrual of the risk of death both with an increasing severity of organ dysfunction and an increasing severity of the diagnostic category of septic state.

Child↗

PubMed2004

Asbestos-related pleuropulmonary diseases: evaluation with low-dose four-detector row spiral CT.

PURPOSE: To evaluate the depiction of lung and pleural asbestos-related lesions with low-dose four-detector row spiral computed tomography (CT). MATERIALS AND METHODS: Eighty-three male workers with a mean duration of occupational exposure to asbestos of 18 years underwent CT as part of a medicolegal investigation. CT examination included low-dose multi-detector row spiral CT of the entire thorax, with reconstruction of contiguous 5-mm-thick images, and thin-section CT, which served as the reference standard for the detection of pleural and parenchymal asbestos-related abnormalities. Two main groups of abnormalities were identified: (a) pleural plaques and diffuse pleural thickening and (b) thickened interstitial short lines, curvilinear subpleural lines, ground-glass opacity with or without bronchiectasis, and honeycombing. The frequencies of the depiction of these abnormalities on the low-dose multi-detector row images and the thin-section images were compared by using the McNemar test. RESULTS: No significant differences were observed between the low-dose and thin-section CT images in the depiction of either (a) parietal pleural fibrosis consisting of pleural plaques (identified in 67 [81%] vs 65 [78%] workers, P =.157), which appeared mainly as thick, calcified pleural linear structures; or (b) features of parenchymal fibrosis, which consisted of various combinations of intralobular and septal lines (identified in 12 [14%] vs 13 [16%] workers, P =.564), subpleural curvilinear lines (identified in 10 [12%] vs eight [10%] workers, P =.157), and ground-glass opacity with (identified in six [7%] vs six [7%] workers) or without (identified in five [6%] vs three [4%] workers, P =.317) traction bronchiectasis. A honeycombing pattern was depicted on only the thin-section CT images (P <.001). Emphysema (identified in 26 [31%] vs 14 [17%] workers at low-dose and thin-section CT, respectively; P <.001) and noncalcified nodules (identified in 18 [22%] workers vs one [1%] worker, P <.001) were depicted significantly more frequently on the low-dose images than on the thin-section images. CONCLUSION: Low-dose multi-detector row spiral CT accurately depicts asbestos-related disease.

Aged↗

PubMed2004

Cognitive and SPECT characteristics predict progression of Parkinson's disease in newly diagnosed patients.

OBJECTIVE: To identify features in cognitive functioning and regional cerebral blood flow (rCBF) in newly diagnosed Parkinson's disease (PD) patients and to determine whether these factors are able to predict the progression of the disease in general and the development of cognitive decline in particular. METHODS: 50 previously treatment-naive PD patients participated in the study. Cognitive assessment and SPECT were performed twice: at the time of diagnosis and then 3 years later. Six patients died or refused to continue. The Mattis dementia rating scale, the WAIS-R digit span test, a word list learning/recall test, a word fluency task and the Stroop word-colour test were used to assess cognitive function. rCBF was measured in 10 pairs of regions of interest. Principal component analysis of the data from the final examination was used to determine which variables allowed the formation of patient subgroups. Thereafter, factorial discriminant analysis (FDA) was performed in order to obtain a predictive model of these final classes. RESULTS: A stepwise procedure enabled the identification of 3 clusters (26, 16 and 2 patients). As the patients in the smallest cluster met the criteria for dementia at the final examination, they were discarded from further analyses. All the cognitive variables contributed to the constitution of the two other clusters. Age, educational level and all the rCBF parameters also contributed but to a lesser extent. Comparison of these groups showed reduced overall cognitive efficiency and an exacerbated subcorticofrontal syndrome in the 16-patient cluster. FDA showed that the best predictive model for the final classes was based on 7 variables: educational level, semantic and alternating word fluency, Stroop interference index and the right medial frontal, left parietal and left lenticular nucleus rCBF findings. CONCLUSION: Even though both cognitive and rCBF parameters help predict the progression of newly diagnosed PD patients and bearing in mind the limitations of the SPECT method used here, it appears that the contribution of cognitive assessment is greater than that of rCBF measurement.

Aged↗

PubMed2003

Mediastinal lymphadenopathy in congestive heart failure: a sequential CT evaluation with clinical and echocardiographic correlations.

The aim of this study was to evaluate the frequency and evolution after treatment of mediastinal lymphadenopathy associated with congestive left heart failure on CT scans in correlation with clinical and echocardiographic findings. Thirty-one consecutive patients with subacute left heart failure underwent a clinical evaluation using the NYHA classification, a CT examination, and transthoracic echocardiography at the time of initial presentation (T1). After initiation of medical treatment (T2), follow-up CT scans were systematically obtained together with a clinical evaluation. At T1, all patients showed severe (type III: n=12, 39%; type IV: n=12, 39%) to moderate (type I, n=1, 3%; type II, n=6, 19%) dyspnea with a mean ejection fraction of 39% (range 22-74%). On initial CT scans, enlarged mediastinal lymph nodes were seen in 13 patients (42%) with blurred contours in 5 patients (16%) and hazy mediastinal fat in 1 patient (3%). Significant decrease in the size of lymphadenopathy was observed between T1 and T2 (T1, n=13, 42% vs T2, n=10, 32%; p<0.05) with a concurrent decrease in the severity of dyspnea (grade III-IV dyspnea at T1, n=24, 78% vs grade I-II dyspnea at T2, n=26, 83.5%). Patients with enlarged lymph nodes at T1 showed: (a) a significantly lower ejection fraction at echocardiography than those without lymphadenopathy (mean+/-SD value: 34+/-12.9 vs 43+/-13.8%; p=0.04); (b) a significantly larger diameter of the right superior pulmonary vein (mean+/-SD value: 17+/-2.75 vs 14+/-3.9 mm; p=0.04); and (c) a higher frequency of abnormal peribronchovascular thickening ( n=5 vs n=1; p=0.06). Mediastinal lymphadenopathy associated with subacute left heart failure was observed in 13 patients (42%), showing regression after initiation of treatment in 8 of 13 patients (62%).

Aged↗

PubMed2003

Multi-detector row spiral CT angiography of the thoracic outlet: dose reduction with anatomically adapted online tube current modulation and preset dose savings.

PURPOSE: To evaluate image quality obtained with anatomically adapted online tube current modulation and preset minimum dose savings at multi-detector row spiral computed tomographic (CT) angiography of the thoracic outlet. MATERIALS AND METHODS: A total of 100 patients were evaluated for thoracic outlet arterial syndrome with spiral CT angiography (collimation, 4 x 1 mm; pitch, 1.75) both with and without dose reduction by means of anatomically adapted online tube current modulation and preset minimum dose savings. Preset minimum savings of 20% and of 32% were applied in two groups of 50 patients (groups 1 and 2). In each group, low-dose scanning was performed in 25 patients in the neutral position and in 25 patients after postural maneuver. Tube current-time product, noise, presence and quality of graininess and of linear streak artifacts on transverse CT scans, and diagnostic value of sagittal reformations and volume-rendered images were evaluated and recorded for each data set. chi2 test was used to compare frequencies; paired Wilcoxon rank test, to compare subjective and objective image quality scores. P <.05 indicated a significant difference. RESULTS: In group 1, mean tube current-time product was 3225 mAs for reference scans and 2101 mAs for low-dose scans (mean reduction, 35%; range, 27%-47%). In group 2, mean was 3070 mAs for reference scans and 2068 mAs for low-dose scans (mean reduction, 33%; range, 17%-38%). In group 1, no differences in frequencies of graininess and linear streaking or in noise level were found between images acquired with or without dose reduction. In group 2, no difference was found in noise level between low-dose and reference scans. On low-dose scans, moderate linear streaking was observed with lower frequency and moderate graininess was observed with higher frequency, but artifacts did not compromise image quality or prevent confident assessment of arterial diameter in the three compartments of the thoracic outlet. CONCLUSION: Online tube current modulation with a preset minimum dose saving of 20% allowed 35% reduction in mean tube current-time product, with no loss in image quality.

Adult↗

PubMed2003

Validation of the paediatric logistic organ dysfunction (PELOD) score: prospective, observational, multicentre study.

BACKGROUND: Multiple organ dysfunction syndrome is more frequent than death in paediatric intensive care units. Estimation of the severity of this syndrome could be a useful additional outcome measure in clinical trials in such units. We aimed to validate the paediatric logistic organ dysfunction (PELOD) score and estimate its validity when recorded daily (dPELOD). METHODS: We did a prospective, observational, multicentre cohort study in seven multidisciplinary, tertiary-care paediatric intensive care units of university-affiliated hospitals (two French, three Canadian, and two Swiss). We included 1806 consecutive patients (median age 24 months; IQR 5-90). PELOD score includes six organ dysfunctions and 12 variables and was recorded daily. For each variable, the most abnormal value each day and during the whole stay were used in calculating the dPELOD and PELOD scores, respectively. Outcome was vital status at discharge. We used Hosmer-Lemeshow goodness-of-fit tests to evaluate calibration and areas under receiver operating characteristic curve (AUC) to estimate discrimination. FINDINGS: 370 (21%) patients had no organ dysfunction, 471 (26%) had one, 457 (25%) had two, and 508 (28%) had three or more. Case fatality rate was 6.4% (115 deaths). PELOD score was significantly higher in non-survivors (mean 31.0 [SE 1.2]) than survivors (9.4 [0.2]; p<0.0001). Calibration (p=0.54) and discrimination (AUC=0.91, SE=0.01) of PELOD and dPELOD (p> or =0.39; AUC> or =0.79) scores were good. INTERPRETATION: PELOD and dPELOD scores are valid outcome measures of the severity of multiple organ dysfunction syndrome in paediatric intensive care units; their use should significantly reduce the sample size required to complete clinical trials in critically ill children.

Adolescent↗

PubMed2003

Diagnosis of bronchiectasis with multislice spiral CT: accuracy of 3-mm-thick structured sections.

The aim of this study was to evaluate the accuracy of 3-mm-thick reconstructed sections in the diagnosis of bronchiectasis with multislice CT (MSCT). Forty consecutive patients suspected of bronchiectasis (23 females, 17 males; mean age 51 years) underwent MSCT of the entire thorax with a 4x1-mm collimation (120 kV, 0.5 s/rotation, 80 mAs/slice) and a pitch of 1.75. From each data set (mean z-axis coverage: 257 mm; mean duration: 21 s), two series of images were systematically generated: 1-mm (group 1) and 3-mm (group 2)-thick reconstructed scans. Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial-frequency algorithm. Two observers independently analyzed the presence of bronchiectasis and associated abnormalities in group-1 and group-2 lung images. No significant difference between group 1 and group 2 was found in: (a) the detection of bronchiectasis, identified in 24 patients (60%) in group 1 and in 23 patients (57.5%) in group 2 ( p=0.08); (b) the evaluation of the extent of bronchiectasis, identifying focal bronchiectasis in 10 patients (25%) in group 1 and 7 patients (17.5%) in group 2 ( p=0.39) and multifocal bronchiectasis in 16 patients (40%) in both groups; (c) the characterisation of bronchiectasis (cylindral bronchiectasis: group 1, n=24, 60%; group 2, n=21, 53%, p=0.08); varicose bronchiectasis: group 1, n=5, 12.5%; group 2, n=6, 15%, p=0.56); and cystic bronchiectasis: group 1, n=2, 5%; group 2, n=2, 5%). Apart from the identification of abnormal bronchial wall thickening (group 2, n=35, 87.5%, vs group 1, n=31, 77.5%, p<0.05), recognition of associated bronchopulmonary anomalies did not differ between the two groups. This study demonstrates a comparable accuracy of the 3- and 1-mm-thick reconstructed scans in the detection and characterization of bronchiectasis. These results suggest the potential usefulness of 3-mm-thick scans generated from 4x2.5-mm acquisitions in the screening of bronchiectasis, which would allow a 20% radiation dose reduction compared with the present investigation.

Adult↗

PubMed2003

Effects of subthalamic nucleus stimulation and levodopa treatment on gait abnormalities in Parkinson disease.

BACKGROUND: Stimulation of the subthalamic nucleus is proposed for the treatment of patients presenting with severe Parkinson disease. The effect on gait is not clearly established. OBJECTIVES: To evaluate objectively the influence of bilateral subthalamic nucleus stimulation on gait in Parkinson disease and to compare it with the effects of levodopa treatment. METHODS: Ten patients underwent bilateral subthalamic nucleus stimulation. The preoperative and postoperative (3 months after surgery) clinical gait disturbances, as well as spatial and temporal gait parameters, were analyzed in off and on-drug conditions. The gait analysis was performed using a video motion analysis system (optoelectronic VICON system; Oxford Metrics, Oxford, England). RESULTS: In the off condition, there was an improvement after surgery for the total motor score and the gait subscore. In the on-drug condition, there was an improvement in levodopa-induced dyskinesias and the motor score, whereas the gait subscore was unchanged. For the gait parameters measured by the video motion analysis system system, there was also an improvement in the off condition and to a lesser extent in the on-drug condition. CONCLUSIONS: Our method allowed exact quantification of the benefit of surgery on gait parameters. Compared with the levodopa treatment, the effect of stimulation on gait kinematic parameters seems to be qualitatively similar but quantitatively different with a lower benefit on gait velocity and stride length. Concerning the pathophysiology of gait troubles in Parkinson disease, the deficit in control of stride length would be the fundamental deficit. The study underlines the possible role of the subthalamic nucleus on the stride length regulation.

Antiparkinson Agents↗

PubMed2003

[Evaluation of cytological screening for cancers and precancerous lesions of the cervix].

The aim was to study retrospectively different parameters useful for the evaluation of cytological screening for cancers and precancerous lesions of the cervix. The study concerned 23,815 smears obtained consecutively from 18,045 women in 4 years. The proportion of follow up smears was equal to 11.1%. The % of abnormal smears was equal to 10.3% of all smears, 7.7% of screening smears (including 0.85% high grade or invasive lesions) and 30.7% of follow-up smears (including 5.55% high grade lesions). The 20,968 screening smears (from 16,896 women) included 2% unsatisfactory smears, 4.15% Ascus (atypical squamous cells of undetermined significance), 2.6% LSIL (low grade squamous intraepithelial lesion), 0.77% HSIL (high grade SIL), 0.05% squamous carcinomas, 0.10% atypical glandular cells and 0.02% adenocarcinomas. Histological examination of the cervix was obtained in 3.3% of women with negative smears, 17.7% of Ascus, 45.8% of LSIL and 82.9% of HSIL. In 1,082 women with histological examination, an histological diagnosis of high grade or invasive lesion of the cervix was made in 7.2% of women with Ascus, 15.7% of cytological LSIL and 85.1% of cytological HSIL.

Adenocarcinoma↗

PubMed2003

Similarity study on university teaching hospitals in France.

The recent development of hospital information systems in France presently makes it possible to study similarity between establishments based on an official data source, the AGHN. The AGHN is based on three types of information: medical, structural (personnel and material) and economic. Using the PCA (principal component analysis) tool, we can examine the situation of one regional and\or university hospital with regards to others of the same kind.

Age Distribution↗

PubMed2002

Influence of pallidal stimulation and levodopa on gait and preparatory postural adjustments in Parkinson's disease.

In order to assess the influence of the bilateral internal globus pallidus (GPi) stimulation on gait and postural instability in Parkinson's disease (PD), we compared gait kinematic parameters and preparatory postural adjustments before and 3 months after stimulation in off- and on-drug conditions for seven patients. Gait kinematic parameters and displacements of centre of pressure (CP) and shoulder computed before a lateral raising task of the leg, were recorded using optoelectric Vicon system. Levodopa (L-dopa) induced a clear benefit for gait velocity (related to an increase of stride length) and also an increase of swing phase duration. GPi stimulation had a limited effect, since the increase of gait velocity was induced by a concomitant increase of stride length and cadence corresponding to a compensatory mechanism. The benefit on swing phase duration was also moderate. Displacements of CP were improved mainly by L-dopa. GPi stimulation and L-dopa had the same beneficial effect on the speed at which the CP was transferred back towards the support side, the ankle velocity, the onset time for ankle displacement, and the decrease of shoulder amplitude towards the support side, which reflects a better postural adjustment phase. This study, based on an objective method, revealed that chronic bilateral GPi stimulation may improve gait and preparatory postural adjustments in severe PD patients with a more limited effect than L-dopa.

Antiparkinson Agents↗

PubMed2002

Thalidomide in patients with advanced multiple myeloma: a study of 83 patients--report of the Intergroupe Francophone du Myélome (IFM).

BACKGROUND: To evaluate treatment by thalidomide and identify predictive factors of survival, event free survival and response among patients with advanced multiple myeloma treated with thalidomide as single agent therapy. PATIENTS AND TREATMENT: Patients with advanced multiple myeloma (n=83) were treated with an oral dose of thalidomide (median 400 mg/day). At start of treatment, all patients had active disease and 58 (69%) had received at least one autologous transplantation. RESULTS: With a median follow-up of 338 days (range, 247-629 days), 52 patients are alive, whereas 31 died between 8 and 150 days after the first administration of thalidomide. The response to thalidomide was considered as major in 11 patients (13%), partial in 29 patients (35%) and minor in 15 patients (18%), giving a total response rate of 66% (54 out of 83 patients). Thirteen patients had stable disease and 15 patients progressed. In multivariable analysis, age greater than 60 years, short interval between diagnosis and onset of thalidomide, requirement for red blood cell transfusion, IgA isotype, platelets' count <80 x 10(9)/l and serum albumin level <30 g/l at the start of thalidomide were associated with poor outcome. These three last factors produced a simplified prognostic model for patients with advanced myeloma and treated with thalidomide. Thus, among the 38 patients without any of these unfavorable risk features, one-year overall survival and event free survival were 87% and 78%. By contrast, the 43 patients with at least one unfavorable feature had one-year overall survival and event free survival of 40% and 32%, respectively (Log-Rank, P=0.0002 for both). Patients who received > or =34.4 g of thalidomide in the first 90 days of treatment had a better outcome than those who received <34.4 g. However, the mean received daily dose of thalidomide in the first 90 days has not been found to influence survival, event free survival or response. Short-term side effects of thalidomide were generally moderate. CONCLUSION: Thalidomide is an effective treatment for patients with advanced myeloma, in particular, who have no poor-risk features. The poor results achieved by the other patients emphasize the need for prospective protocols using thalidomide in combination, especially with dexamethasone. In addition, further studies are needed to determine the optimal thalidomide dose and duration.

Adult↗

PubMed2002

Assessing association rules and decision trees on analysis of diabetes data from the DiabCare program in France.

Recent advances in information technology have made it possible to solve increasingly complex problems, and also to collect and store huge amounts of information. These vast quantities of data further have to be transformed into relevant value-added and "decision-quality" knowledge. It is against this background that the KDD (Knowledge Discovery in Databases), a multidisciplinary field using computer learning, artificial intelligence, statistics, database technology, expert systems, and data visualization, appeared in the early 90's. In order to assess these technologies in the medical field, we have tested some of these techniques on a large database at our disposal, named DiabCare stemming from the WHO - DiabCare program for the application of the Saint-Vincent Declaration. It contains evaluation data on the health care of patients with diabetes, and in particular, its complications. So far, data analysis has been done using classical statistical methods, and we now intend to make use of such data-mining tools as Associations Rules and Decision and Classification Trees for further exploration of this database. The results presented here show that data mining techniques can be used successfully to extract knowledge from medical databases. The results obtained using Association Rules and especially Decision Trees are very promising.

Algorithms↗

PubMedDate not supplied

Usefulness of coronal reformations in the diagnostic evaluation of infiltrative lung disease.

PURPOSE: To evaluate the diagnostic accuracy of coronal thin sections as an alternative to transverse high-resolution computed tomography (HRCT) scans in the diagnostic approach to infiltrative lung disease (ILD) with multislice computed tomography (MSCT). MATERIALS AND METHODS: Fifty consecutive patients referred for suspicion of ILD underwent MSCT (collimation: 4 mm x 1 mm; pitch: 1.75; scan time: 0.5 seconds; 80 mA per slice) of the entire thorax. Two sets of lung images were systematically reconstructed: 1-mm thick transverse computed tomography (CT) scans (i.e., HRCT scans) (group 1) and 1-mm thick coronal images (group 2). Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial frequency algorithm. Two observers independently analyzed the overall image quality, the presence and distribution of CT features of ILD, and the diagnostic value of group 1 and group 2 lung images. RESULTS: Group 1 and group 2 images were coded as interpretable, with minimal respiratory artifacts in the lower lung zones in two cases (4%). Presence of abnormal lung infiltration was found in 38 patients in group 2 with concordant interpretation of group 1 images. No significant difference was found in the identification of CT features of ILD between group 2 and group 1 (nodules: 32% vs. 30%; lines: 14% vs. 16%; increased attenuation: 24% vs. 26%; fibrosis: 48% vs. 50%; distortion: 46% vs. 50%; and abnormal interfaces: 16% in both groups). Distribution of lung abnormalities in central, peripheral, anterior, and/or posterior lung zones was similarly recognized in group 2 and group 1. In patients with extensive lung infiltration, the vertical predominance of lung changes was more precisely assessed in group 2 (n = 12) than in group 1 (n = 4). For a mean coverage of 260 mm in this study group, the mean number of sections to be interpreted was significantly lower in group 2 (19 sections) than in group 1 (28 sections) (P < 0.01). CONCLUSION: Coronal sections allow a diagnostic approach to ILD as precise as that provided with HRCT scans, based on the interpretation of a significantly reduced number of images.

Adult↗

PubMedDate not supplied

Sixteen-slice multidetector computed tomography pulmonary angiography: evaluation of cardiogenic motion artifacts and influence of rotation time on image quality.

OBJECTIVE: To describe the site and severity of cardiogenic motion artifacts on 16-slice multidetector computed tomography (CT) angiograms of the pulmonary circulation and to determine the impact of the gantry rotation time on image quality. METHODS: Sixty-nine patients underwent nonelectrocardiographically gated 16-slice multidetector CT angiography of the pulmonary circulation with a rotation time of 0.5 second (group 1, n = 37) or 0.375 second (group 2, n = 32). All scans were prospectively analyzed for the presence of cardiogenic motion artifacts in the pulmonary arteries, defined as a blurring of the edges of the pulmonary arteries on lung window settings with or without an artifactual loss of enhancement in the arterial lumen on soft tissue windows ("pseudofilling defect"). In addition, the severity of pulmonary arterial blurring was recorded using a 4-point scale. RESULTS: Fifty-six patients (81%) had at least 1 pulmonary artery affected by cardiogenic motion artifacts. At the level of the central pulmonary arteries, movement artifacts responsible for a blurring of the arterial wall were present in 35 patients (51%), mainly observed at the level of the pulmonary trunk (n = 28, 41% of patients) and right main pulmonary artery (n = 23, 33% of patients); in 2 patients, motion artifact was responsible for a pseudoflap appearance within the arterial lumen (n = 2, 4% of patients). Motion artifacts at the level of lobar pulmonary arteries were noted only in the lower divisions of the lingula (n = 1, 1.5% of patients) and in the left lower lobe (n = 2, 3% of patients). At the level of the segmental pulmonary arteries, motion artifacts were most frequently found in the lower divisions of the left upper lobe (lingula) (n = 19, 27.5% of patients) and left lower lobe (n = 29, 42% of patients). At the subsegmental level, motion artifacts were most common in the lower divisions of the left upper lobe (lingula) (n = 30, 43.5% of patients) and left lower lobe (n = 35, 51% of patients). Pseudofilling defects were depicted at the segmental and subsegmental levels in 28 patients (41% of the study group), almost exclusively located in the lingula and left lower lobe. Cardiogenic motion artifacts were observed with a significantly lower frequency in group 2 (22 of 32 patients, 69%) than in group 1 (34 of 37 patients, 92%) (P = 0.0142), with a concurrent reduction in the frequency of pseudofilling defects identified in 20 patients (54%) in group 1 and in 8 patients (25%) in group 2 (P = 0.0142). CONCLUSION: The use of a 0.375-second rotation time enables significant reduction in the frequency of cardiogenic motion artifacts on 16-slice multidetector CT angiograms of the pulmonary circulation.

Adult↗