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Biomedical subjects

Emmanuel Coche

Publications and source records attributed to Emmanuel Coche.

At least 19 recordsLinked to original sources
PubMed2006

Pulmonary embolism: radiation dose with multi-detector row CT and digital angiography for diagnosis.

PURPOSE: To compare radiation dose delivered at four- and 16-detector row computed tomography (CT) with a dose-modulation program and that delivered at digital angiography for evaluation of pulmonary embolism (PE). MATERIALS AND METHODS: The part of the study involving patients (seven women, four men; mean age, 62 years +/- 16 [standard deviation]; range, 41-85 years) was approved by the institutional review board. Patients gave written informed consent. Exposure was performed with an anthropomorphic phantom with thermoluminescent dosimeters for four-detector row CT without the dose-modulation program and 16-detector row CT without and with the dose-modulation program with standard protocols for pulmonary CT angiography (120 kV, 144 mAs, four and 16 detector rows with 1.00- and 0.75-mm section thickness, respectively). Digital angiograms were acquired with four standard projections at 80 kV. For digital angiography, radiation dose was calculated according to phantom measurements and adapted to acquisition and fluoroscopy times. Distribution of dose was compared for CT and digital angiography. RESULTS: During pulmonary CT angiography, mean radiation dose delivered at middle of chest was 21.5, 19.5, and 18.2 mGy for four-detector row CT and for 16-detector row CT without and with dose-modulation program, respectively. At the same level, a mean dose of 91 mGy was delivered with digital angiography. The dose adjusted to clinical conditions was 139.0 mGy for digital angiography and could be reduced after technical adjustment. Ratios of maximum dose to mean dose were 1.15 and 2.96 for CT and digital angiography, respectively. With application of the dose-modulation program at 16-detector row CT, radiation dose was reduced 15%-20% at the upper chest. CONCLUSION: Multi-detector row CT delivers a lower radiation dose, with better spatial distribution of dose, than does pulmonary digital [corrected] angiography. With 16-detector row CT and a dose-modulation program, radiation dose is decreased during PE work-up.

Adult↗
PubMed2006

Diagnostic accuracy of 16-slice multidetector-row CT for detection of in-stent restenosis vs detection of stenosis in nonstented coronary arteries.

The purpose of this study was to assess the diagnostic accuracy of 16-slice multidetector-row computed tomography (MDCT) for detecting in-stent restenosis. Fifty patients with 69 previously implanted coronary stents underwent 16-slice MDCT before quantitative coronary angiography (QCA). Diagnostic accuracy of MDCT for detection of in-stent restenosis defined as >50% lumen diameter stenosis (DS) in stented and nonstented coronary segments >1.5-mm diameter was computed using QCA as reference. According to QCA, 18/69 (25%) stented segments had restenosis. In addition, 33/518 (6.4%) nonstented segments had >50% DS. In-stent restenosis was correctly identified on MDCT images in 12/18 stents, and absence of restenosis was correctly identified in 50/51 stents. Stenosis in native coronary arteries was correctly identified in 22/33 segments and correctly excluded in 482/485 segments. Thus, sensitivity (67% vs 67% p=1.0), specificity (98% vs 99%, p=0.96) and overall diagnostic accuracy (90% vs 97%, p=0.68) was similarly high for detecting in-stent restenosis as for detecting stenosis in nonstented coronary segments. MDCT has similarly high diagnostic accuracy for detecting in-stent restenosis as for detecting coronary artery disease in nonstented segments. This suggests that MDCT could be clinically useful for identification of restenosis in patients after coronary stenting.

Coronary Restenosis↗
PubMed2006

Accurate estimation of global and regional cardiac function by retrospectively gated multidetector row computed tomography: comparison with cine magnetic resonance imaging.

Retrospective reconstruction of ECG-gated images at different parts of the cardiac cycle allows the assessment of cardiac function by multi-detector row CT (MDCT) at the time of non-invasive coronary imaging. We compared the accuracy of such measurements by MDCT to cine magnetic resonance (MR). Forty patients underwent the assessment of global and regional cardiac function by 16-slice MDCT and cine MR. Left ventricular (LV) end-diastolic and end-systolic volumes estimated by MDCT (134+/-51 and 67+/-56 ml) were similar to those by MR (137+/-57 and 70+/-60 ml, respectively; both P=NS) and strongly correlated (r=0.92 and r=0.95, respectively; both P<0.001). Consequently, LV ejection fractions by MDCT and MR were also similar (55+/-21 vs. 56+/-21%; P=NS) and highly correlated (r=0.95; P<0.001). Regional end-diastolic and end-systolic wall thicknesses by MDCT were highly correlated (r=0.84 and r=0.92, respectively; both P<0.001), but significantly lower than by MR (8.3+/-1.8 vs. 8.8+/-1.9 mm and 12.7+/-3.4 vs. 13.3+/-3.5 mm, respectively; both P<0.001). Values of regional wall thickening by MDCT and MR were similar (54+/-30 vs. 51+/-31%; P=NS) and also correlated well (r=0.91; P<0.001). Retrospectively gated MDCT can accurately estimate LV volumes, EF and regional LV wall thickening compared to cine MR.

Algorithms↗
PubMed2006

Characterization of acute and chronic myocardial infarcts by multidetector computed tomography: comparison with contrast-enhanced magnetic resonance.

BACKGROUND: We evaluated whether contrast-enhanced multidetector computed tomography (CE-MDCT) might characterize myocardial infarct (MI) with patterns similar to those obtained by contrast-enhanced magnetic resonance (CE-MR) and studied the underlying mechanisms. METHODS AND RESULTS: In vivo infarct characterization by CE-MDCT was shown to be feasible between 4 and 20 minutes after contrast injection in 7 pigs with MI. Subsequently, in 16 patients with acute MI and 21 patients with chronic MI, contrast patterns by CE-MDCT were related to CE-MR. Eighteen patients had hypoenhanced regions on early CE-MDCT images at the time of coronary imaging, and 34 patients had hyperenhanced regions on images acquired 10 minutes later. On a segmental basis, there was moderately good concordance of early hypoenhanced regions (92%, kappa=0.54, P<0.001) and late hyperenhanced regions (82%, kappa=0.61, P<0.001) between CE-MDCT and CE-MR. Absolute sizes of early hypoenhanced (6+/-16 versus 7+/-16 g, P=0.25) and late hyperenhanced (36+/-34 versus 31+/-40 g, P=0.14) regions were similar on CE-MDCT and CE-MR and were highly correlated (r=0.93, P<0.001 and r=0.89, P<0.001 respectively). In 8 retrogradely perfused infarcted rabbit hearts, contrast kinetics of iomeprol were similar to gadodiamide, ie, slow wash in (8.7+/-6.7 versus 1.2+/-0.3 minutes, P<0.001) in infarct core and slow washout (20+/-12 versus 2.5+/-0.5 minutes, P<0.001) in both infarct core and rim compared with the remote region. CONCLUSIONS: Because iodated contrast agents have similar kinetics in infarcted and noninfarcted myocardium as gadolinium DPTA, CE-MDCT can characterize acute and chronic MI with contrast patterns similar to CE-MR. CE-MDCT may thus provide important information on infarct size and viability at the time of noninvasive coronary imaging.

Acute Disease↗
PubMed2005

Head-to-head comparison of three-dimensional navigator-gated magnetic resonance imaging and 16-slice computed tomography to detect coronary artery stenosis in patients.

OBJECTIVES: The purpose of this research was to compare the diagnostic accuracy of three-dimensional navigator-gated magnetic resonance (MR) imaging and 16-slice multidetector row computed tomography (MDCT) versus quantitative coronary angiography (QCA) for the detection of coronary artery stenosis in patients. BACKGROUND: Both MR and MDCT are novel non-invasive tests, which have been proposed for noninvasive detection of coronary artery disease. Yet their diagnostic accuracy has not been directly compared in the same population. METHODS: Fifty-two patients underwent coronary MR and 16-slice MDCT before invasive coronary angiography. Diameter stenosis (DS) severity in vessels >1.5-mm reference diameter were graded visually and measured quantitatively on both MR and MDCT images. Diagnostic accuracy of both methods was compared using QCA as the reference test. RESULTS: According to QCA, 81 of 452 (18%) coronary segments with >1.5 mm diameter had >50% DS. By visual analysis, MR and MDCT had similar sensitivity (75% vs. 82%, p = NS), specificity (77% vs. 79%, p = NS), and diagnostic accuracy (77%, vs. 80%, p = NS) for detection of >50 % DS. Quantitative measures of DS by MR (r = 0.60, p < 0.001) and MDCT (r = 0.75, both p < 0.001) correlated well with QCA. Receiver-operating characteristic analysis demonstrated that quantification of DS severity improved the diagnostic accuracy of MDCT (area under curve [AUC] 0.81 vs. 0.92, p < 0.001) but not that of MR (AUC 0.78 vs. 0.83, p = NS). CONCLUSIONS: Visual assessment of coronary diameter stenosis severity by MR or MDCT allows identification of significant coronary artery disease with a similar high diagnostic accuracy. Quantitative analysis significantly further improves the diagnostic accuracy of MDCT but not that of MR.

Aged↗
PubMed2005

Evaluation of biventricular ejection fraction with ECG-gated 16-slice CT: preliminary findings in acute pulmonary embolism in comparison with radionuclide ventriculography.

This study aimed to assess the feasibility of cardiac global function evaluation during a whole-chest multi-slice CT (MSCT) acquisition in patients referred for suspicion of pulmonary embolism (PE), and to compare the results with planar equilibrium radionuclide ventriculography (ERNA). Ten consecutive haemodynamically stable patients (six female, four male; mean age 69.7 years; heart rate 65-99 bpm) with suspicion of PE underwent an MSCT and ERNA within a 6 h period. CT acquisition was performed after contrast medium injection by using 16x1.5 mm collimation and retrospective ECG gating. Left ventricular (LVEF) and right ventricular (RVEF) ejection fractions were calculated using dedicated three-dimensional software. Relationships between measurements obtained with MSCT and ERNA were assessed using linear regression analysis and reliability of MSCT was assessed with intra-class correlation coefficient. Bland-Altman analysis was performed to calculate limits of agreement between MSCT and ERNA. MSCT was performed successfully in ten patients with a mean acquisition time of 16.5+/-2.8 s. Functional cardiac evaluation was possible on CT for all patients except for one due to poor opacification of right ventricle. Linear regression analysis showed a good correlation between MSCT and ERNA for the LVEF (R=0.91) and the RVEF (R=0.89) measurements. Intra-class correlation was superior for LVEF (0.92) than for the RVEF (0.68). Bland-Altman plots demonstrated that MSCT substantially overestimated the ERNA RVEF. Morphological CT data demonstrated PE in four of ten of patients and alternative diagnoses in five of ten patients. Our study reveals that MSCT with retrospective ECG gating may provide in one modality a morphological and a functional cardiopulmonary evaluation. Comparison with ERNA demonstrated a good correlation for both ventricular ejection fractions.

Aged↗
PubMed2005

Inter-observer variability in the delineation of pharyngo-laryngeal tumor, parotid glands and cervical spinal cord: comparison between CT-scan and MRI.

BACKGROUND AND PURPOSE: The goal of this study was to compare the inter-observer variability between CT and MRI for the delineation of pharyngo-laryngeal SCC, parotid glands and spinal cord. PATIENTS AND METHODS: Twenty pharyngo-laryngeal tumors were delineated by five observers on CT and MRI, using consistent delineation guidelines. Spinal cords and parotid glands were also delineated on CT and MRI by three observers. Mean GTVs and coefficients of variation were calculated for each observer and compared using ANOVA and its derived Pearson intra-class coefficient (R). For GTVs, a mismatch analysis (ratio between intersection and union volumes) was also performed. RESULTS: Regarding oropharyngeal GTVs (n=10), no significant difference was observed between observers either with CT (33.9, 31.1, 32, 34 and 34.7 ml, five observers, P=0.47) or with MRI (30.5, 29.4, 30.1 and 31.5 ml, four observers, P=0.59). CVs (13.6 vs 12.9%), (0.98 vs 0.99) and mismatches (0.43 vs 0.42) between CT and MRI did not significantly differ. Regarding laryngeal-hypopharyngeal GTVs (n=10), no significant difference was observed between observers either on CT (18.1, 20.7, 20.9, 19.3 and 21.9 ml, five observers, P=0.29) or on MRI (19.3, 21.5, 20, 22.1 and 21.8 ml, five observers, P=0.16). CVs (20.2 vs 13.8%), (0.94 vs 0.94) and mismatches (0.31 vs 0.41) were comparable. Regarding OARs, a small but significant difference in mean parotid volume was observed between observers (P<0.001) and between modalities (P<0.001) (CT: 34.8, 29.4, and 26.8 ml; MRI: 30.6, 27.9 and 20.4 ml). Similar results were obtained for mean spinal cord volumes (CT: 10.7, 10.6, and 9.5 ml; MRI: 8.7, 8.5 and 8.2 ml; P=0.05).

Carcinoma, Squamous Cell↗
PubMed2004

Transdiaphragmatic peritoneal hernia complicating peritoneal dialysis: demonstration with spiral computed tomography peritoneography and peritoneal scintigraphy.

The authors describe a rare case of peritoneal transdiaphragmatic hernia discovered immediately after a car accident in a young male patient on peritoneal dialysis. The potential role of CT peritoneography and peritoneal scintigraphy to demonstrate and understand thoracic complications of ambulatory peritoneal dialysis is discussed.

Accidents, Traffic↗
PubMed2004

Coronary artery stenosis: direct comparison of four-section multi-detector row CT and 3D navigator MR imaging for detection--initial results.

PURPOSE: To prospectively compare the diagnostic accuracy of multi-detector row computed tomography (CT) and of three-dimensional (3D) navigator magnetic resonance (MR) imaging in patients referred for conventional coronary angiography for detection of coronary artery stenosis. MATERIALS AND METHODS: All patients gave written informed consent for the study, which was approved by the local ethics committee. Twenty-seven patients underwent multi-detector row CT and 3D navigator free-breathing MR imaging a mean of 5 days before undergoing invasive coronary angiography. The acquired multi-detector row CT and MR images were graded for the presence of greater than 50% stenosis in vessels larger than 1.5 mm in diameter. The diagnostic accuracies of the two examinations were compared with that of quantitative coronary angiography (QCA) by using the McNemar test. RESULTS: Owing to claustrophobia, MR images were not acquired in one patient; thus, 26 patients were included for analysis. According to QCA findings, 21 of the 26 patients had significant coronary artery disease and 58 (20%) of a total of 294 coronary artery segments larger than 1.5 mm in diameter had significant (>50%) stenosis. Multi-detector row CT had significantly higher sensitivity (46 [79%] of 58 segments) than MR imaging (36 [62%] segments, P < .05) for detection of segments with significant stenosis. Conversely, MR imaging had significantly higher specificity (198 [84%] of 236 segments) than did CT (168 [71%] segments, P < .001) for exclusion of segmental coronary artery stenosis. Both examinations had high negative predictive value for exclusion of segmental stenosis: 93% (168 of 180 segments) for CT and 90% (198 of 220 segments) for MR imaging. The overall diagnostic accuracy of MR imaging (80% [234 of 294 segments]) was significantly higher than that of CT (73% [214 segments], P < .05). CONCLUSION: MR imaging had significantly higher diagnostic accuracy than multi-detector row CT in the evaluation of coronary artery stenosis. Both techniques have high negative predictive value, making them particularly useful for ruling out coronary artery disease in symptomatic patients.

Adult↗
PubMed2004

Pulmonary embolism findings on chest radiographs and multislice spiral CT.

Multislice spiral CT is becoming an increasingly important tool for diagnosing pulmonary embolism. However, in many instances, a chest radiograph is usually performed as a first-line examination. Many parenchymal, vascular, and other ancillary findings may be observed on both imaging modalities with a highly detailed depiction of abnormalities on multislice CT. A comprehensive review of chest radiograph findings is presented with side-by-side correlations of CT images reformatted mainly in the frontal plane.

Acute Disease↗
PubMed2004

Rotterdam and Brussels CT-based neck nodal delineation compared with the surgical levels as defined by the American Academy of Otolaryngology-Head and Neck Surgery.

PURPOSE/OBJECTIVE: Rotterdam and Brussels have independently published guidelines for the definition and delineation of CT-based neck nodal Levels I-VI. This paper first reports on the adequacy of contouring of the Rotterdam delineation protocol. Rotterdam and Brussels differed slightly in translating the original surgical level definitions as proposed by the 2002 American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) to CT guidelines. To adapt to the surgical level definitions to come to a unifying concept, adjustments of both CT-based classifications are proposed. METHODS AND MATERIALS: The clinical neck nodal target volumes of patients irradiated in Rotterdam by three-dimensional conformal radiotherapy (3D-CRT) between December 1998 and March 2001 were reviewed. Thirty-four patients with N0 and 27 patients with N+ disease with primary tumors located in the oral cavity (n = 1) oropharynx (n = 24), hypopharynx (n = 7), and larynx (n = 29) were evaluated. Seven patients underwent unilateral (3 N0 patients, 4 N+ patients) and 54 underwent bilateral (31 N0 patients, 23 N+ patients) irradiation of the neck. In 11 N+ patients, 3D-CRT of the neck was followed by unilateral neck dissection. The dose to the primary and nonresected N+ necks was 70 Gy and to the N0 neck was 46 Gy. Neck levels were analyzed for adequacy of contouring, dose distribution, and patterns of relapse. The mean dose and the percentage of the volume receiving a minimum of 95% (V95) or >107% (V107) of the prescribed dose was computed. RESULTS: In 4 patients treated with bilateral 3D-CRT, contouring was not in concordance with the guidelines of the protocol. The V95 and V107 in the 81 adequately contoured N0 necks (63 irradiated N0 necks from 33 N0 patients, 18 irradiated N0 necks from 24 N+ patients) was 95.6% and 6.3%, respectively. For the 26 N+ necks (15 N+ necks from 13 N+ RT-only patients, 11 N+ necks from 11 preoperatively irradiated patients), the V95 and V107 was 94.6% and 6.7%, respectively. With a median follow-up of 29 months, in 4 (8.6%) of 46 patients treated by 3D-CRT only, regional relapse was found. An actuarial regional and locoregional relapse-free survival and disease-free survival rate at 3 years of 90%, 78%, and 68%, respectively, was observed. All regional relapses were observed in the N0 necks of patients with supraglottic laryngeal carcinoma. Taking the surgical 2002 AAO-HNS classification as a reference, adjustments are proposed for the Rotterdam and Brussels delineation protocols to arrive at a unified CT-based neck nodal classification. CONCLUSION: Adequate dose coverage for the Rotterdam CT-based contours of the neck nodal levels was found. In the RT-only patients, only four failures were observed: one regional and three locoregional relapses. As a next step in optimizing the current Rotterdam and Brussels CT-based delineation protocols, adaptations are proposed to resolve the discrepancies compared with the 2002 AAO-HNS surgical classification.

Belgium↗