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Biomedical subjects

M Coulomb

Publications and source records attributed to M Coulomb.

At least 19 recordsLinked to original sources
PubMed2000

Paradoxical emboli: demonstration using helical computed tomography of the pulmonary artery associated with abdominal computed tomography.

We report the case of a 60-year-old woman with a recent history of a cerebrovascular accident. Because of clinical suspicion of pulmonary embolism and negative Doppler ultrasound findings of the lower limbs, spiral computed tomography of the pulmonary artery was performed and demonstrated pulmonary emboli. We emphasize the role of computed tomography of the abdomen, performed 3 min after the thoracic acquisition, which showed an unsuspected thrombus within the abdominal aorta and the left renal artery with infarction of the left kidney. Paradoxical embolism was highly suspected on computed tomography data and confirmed by echocardiography which demonstrated a patent foramen ovale.

Aorta, Abdominal↗
PubMed2000

Benign abnormalities and carcinoid tumors of the central airways: diagnostic impact of CT bronchography.

OBJECTIVE: The purpose of this retrospective study was to determine the added diagnostic value, if any, of CT bronchography for the detection and characterization of benign abnormalities and typical carcinoid tumors of the central airways. MATERIALS AND METHODS: We used bronchoscopy and helical CT to examine 238 bronchial sections in 28 patients with 32 bronchial abnormalities and in five patients with normal bronchoscopy results. Postprocessing consisted of CT bronchography based on surface rendering. Images were interpreted independently by two observers (a radiologist and a pneumonologist) who were not informed of the bronchoscopy results. After initial interpretation of axial CT scans, the observers analyzed the axial CT scans with CT bronchograms. Results were evaluated for gain in diagnostic accuracy and in confidence. RESULTS: Mean sensitivity for detection of abnormal bronchial sections was 89% (range, 87-90%) for axial CT and 92% (range, 90-94%) for axial CT with CT bronchography (not significant). Mean specificity of both approaches exceeded 99%. A correct diagnosis of the nature of the bronchial abnormalities was proposed for 68% of the cases in which axial CT was used alone and in 76% in which both axial CT and CT bronchography were used (not significant). The addition of CT bronchography significantly increased the confidence of the pneumonologist in the diagnoses. CONCLUSION: Axial CT remains the technique of choice to detect and characterize benign abnormalities of the airways. CT bronchography provides little diagnostic gain but increases the confidence of chest physicians in the interpretation of CT scans for the assessment of benign abnormalities and typical carcinoids of the central airways.

Adolescent↗
PubMed2000

[3D virtual imaging of the upper airways].

The different three dimensional reconstructions of the upper airways that can be obtained with spiral computed tomograpy (CT) are presented here. The parameters indispensable to achieve as real as possible spiral CT images are recalled together with the advantages and disadvantages of the different techniues. Multislice reconstruction (MSR) produces slices in different planes of space with the high contrast of CT slices. They provide information similar to that obtained for the rare indications for thoracic MRI. Thick slice reconstructions with maximum intensity projection (MIP) or minimum intensity projection (minIP) give projection views where the contrast can be modified by selecting the more dense (MIP) or less dense (minIP) voxels. They find their application in the exploration of the upper airways. Surface and volume external 3D reconstructions can be obtained. They give an overall view of the upper airways, similar to a bronchogram. Virtual endoscopy reproduces real endoscopic images but cannot provide information on the aspect of the mucosa or biopsy specimens. It offers possible applications for preparing, guiding and controlling interventional fibroscopy procedures.

Bronchi↗
PubMed1999

Endovascular treatment of superior vena cava obstruction in patients with malignancies.

The aim of this study was to report our experience on the management of superior vena cava obstruction (SVCO) secondary to malignant disease, using endovascular procedures. Twenty-six patients with SVCO due to primary or secondary tumors of the lung or the mediastinum, or catheter inserted for treatment of an extra-thoracic neoplasm, had an endovascular therapy which consisted of stenting, angioplasty, thrombo-aspiration or local fibrinolysis. Immediately after the procedure, rapid relief of symptoms occurred in 24 (90 %) of the patients. The mean Kishi's score decreased from 5.5 to 0.96. Immediate complications included one death related to pericarditis bleeding following fibrinolysis. Three patients relapsed after 20 days, 4 months and 6 months, and needed a second stenting. At 6 months the primary patency rate was 83 % and the secondary patency rate was 89 %. Endovascular treatment of SVCOs is a simple and safe procedure to restore the patency of the superior vena cava in malignant SVCO. It should be indicated in most cases as first-line treatment and performed as early as possible.

Adult↗
PubMed1999

[Apprenticeship in radiology at the University Hospital Center in Grenoble: research on the most effective methods].

From analyses of strengths and weaknesses of the apprenticeship of radiology in France, of existing pedagogic methods, of time constraints within clinical settings and of scientific theories of teaching and learning, the authors define objectives that teaching should target and propose a new method of instruction problem and practise-based. The method appears applicable in French radiology departments. It should forster early acquisition by residents of professional attitudes and way of thinking, and make them active self-directed learners.

Attitude of Health Personnel↗
PubMed1998

Computer-assisted spine surgery.

The aim of this study was to improve the reliability of pedicle screw insertion. Transpedicle screw insertion may cause neurological, vascular, and mechanical complications. Previous studies of surgical procedures have shown a significant rate of incorrect placement of the screw ranging from 10 to 40%. A new technique that combines preoperative computed tomography (CT) imaging with intraoperative passive navigation was used to perform 64 pedicle screw insertions in the thoracolumbar region. At the same time, 64 pedicle screw insertions were performed manually in the same region and on the same vertebral levels. Surgery was followed in all cases by postoperative radiographs and computed tomography examination, which allowed measurements of screw position relative to pedicle position to be performed. A comparison between the two groups showed that six screws in 64 vertebra (9%) had incorrect placement with the computer-assisted technique whereas 28 screws in 64 vertebra (44%) had incorrect placement with manual insertion. The intraoperative accuracy provided by the computer after registration was better than 1 mm. The good results obtained are similar to those reported in the literature. The cortex penetration observed with the computer-assisted technique was not imputed to computer failure. Errors by the surgeon in acquiring data in the pre- and perioperative steps may explain the six incorrect screw placements. This clinical experience confirms that the accuracy and the reliability of this computer-assisted technique are good.

Bone Screws↗
PubMed1998

Pedicle screw placement using image guided techniques.

Clinical evaluation of a computer assisted spine surgical system is presented. Eighty pedicle screws were inserted using computer assisted technology in thoracic and lumbar vertebrae for treatment of different types of disorders including fractures, spondylolisthesis, and scoliosis. Fifty-two patients with severe fractures, spondylolisthesis, or pseudoarthrosis of T10 to L5 were treated using a computer assisted technique on 1/2 the patients and performing the screw insertion manually for the other 1/2. At the same time, 28 pedicle screws were inserted in T12 to L4 vertebrae for scoliosis with the help of the computer assisted technique. Surgery was followed in all cases (66 vertebrae; 132 pedicle screws) by postoperative radiographs and computed tomographic examination, on which measurements of screw position relative to pedicle position could be done. For fractures, spondylolisthesis, or pseudarthrosis, comparison between the two groups showed that four screws in 52 (8%) vertebrae had incorrect placement with computer assisted technique whereas 22 screws in 52 (42%) vertebrae had incorrect placement with manual insertion. In patients with scoliosis, four screws in 28 (14%) vertebrae had incorrect placement. In all of the patients (132 pedicle screws) there were no neurologic complications. These results show that a computer assisted technique is much more accurate and safe than manual insertion.

Bone Screws↗
PubMed1998

[Puerperal thrombophlebitis and the ovarian vein with extension to the inferior vena cava].

PURPOSE: To assess US, CT and MR findings in women having puerperal ovarian vein thrombosis with clot protrusion into the inferior vena cava. PATIENTS, MATERIAL AND METHODS: We retrospectively reviewed the duplex US (n = 9), CT (n = 5) and MR (n = 5) examinations of 9 patients with 8 right ovarian vein thrombosis, and one left ovarian vein thrombosis. RESULTS: US findings allowed for the diagnosis of ovarian vein thrombosis in all patients in showing enlarged tubular echogenic thrombus within the retroperitoneum with clot protrusion in the IVC in all cases. CT scan and MRI demonstrated ovarian vein thrombosis in all the cases in which it was performed but failed to show a mobile thrombus within the IVC in one patient. CONCLUSION: Duplex US is a reliable technique to show puerperal ovarian vein thrombosis and its extension to the IVC. CT scan and MR imaging can be used to precise the extension to the IVC.

Adult↗
PubMed1998

[CT x-ray evaluation of abdominal and pelvic veins in patients suspected of acute pulmonary embolism with negative Doppler sonography].

PURPOSE: To address prospectively the potential of CT of the abdomen and pelvis to demonstrate deep vein thrombosis in patients suspected of acute pulmonary embolism and investigated with helical CT of the pulmonary arteries. MATERIAL AND METHODS: 197 patients presenting non-diagnostic scintigraphy and negative Doppler US of lower limbs and IVC were included. They had helical CT of the pulmonary arteries (5mm collimation, 1:1 pitch, reconstruction every 2.5 mm, injection of 120 mL of contrast media at a rate of 3 mL/sec). Ninety seconds after the end of the thoracic acquisition, abdominal and pelvic CT were acquired (7 mm collimation every 12 mm). RESULTS: 3 (1.5%) of 197 patients had an unknown thrombosis of the caval system (renal vein, ovarian vein, lilac veins). A fourth patient had an unknown thrombosis of the mesenteric vein. All these patients had a pulmonary embolism (4/40). None of the 157 patients without pulmonary embolism at helical CT showed deep venous thrombosis. CONCLUSION: In our study, CT of the abdomen and pelvis disclosed an unknown thrombosis of a deep vein of the abdomen and pelvis that can explain the pulmonary embolism in 7.5% of patients.

Abdomen↗
PubMed1998

[Does a universal strategy of acute pulmonary embolism diagnosis exist today?].

In this review, we demonstrate that there is no universal diagnostic strategy for non-severe acute pulmonary embolism. The first part of the article is devoted to the concept of thromboembolic disease: its frequency, severity and diagnostic difficulties. The second part analyzes the tools used for diagnosis of pulmonary angiography, noninvasive venous studies, and helical CT angiography. The last part discusses current diagnostic algorithms for pulmonary embolism and the changes that may be introduced by the use of helical CT in clinical practice. The potential for MR imaging id discussed.

Acute Disease↗
PubMed1997

Central airway stenoses: preliminary results of spiral-CT-generated virtual bronchoscopy simulations in 29 patients.

The purpose of this study was to determine the feasibility of using virtual bronchoscopy simulations to depict stenoses of the tracheobronchial tree. Virtual bronchoscopy simulations, based on ray casting, were applied to spiral-CT data sets of 29 patients presenting 41 stenoses of the central airways, proved with fiberoptic bronchoscopy. Simulations of the inner walls of the airways were of good quality in 27 of 29 patients. Airway stenoses were depicted in 39 of 41 cases. Evaluation of the length of stenoses and surrounding tissues required simultaneous display of multiplanar reformations. Virtual bronchoscopy provides a valuable road map for bronchoscopy, in an image format familiar to bronchoscopists.

Adult↗
PubMed1997

Acute pulmonary embolism: role of helical CT in 164 patients with intermediate probability at ventilation-perfusion scintigraphy and normal results at duplex US of the legs.

PURPOSE: To assess prospectively the clinical effectiveness of helical computed tomography (CT) in the evaluation of patients with unresolved suspicion for pulmonary embolism (PE). MATERIALS AND METHODS: Helical CT was performed in 164 consecutive patients suspected of having acute PE, intermediate probability at ventilation-perfusion (V-P) scintigraphy, and normal findings at duplex ultrasonography (US) of the legs. Fifteen patients also underwent pulmonary angiography. Helical CT results were analyzed immediately to help plan anticoagulant treatment. If helical CT did not show PE, anticoagulant treatment was not indicated. Clinical outcome for these patients was assessed during 3-month follow-up. RESULTS: In 40 (24.4%) of 164 patients, the diagnosis of PE was based on results at helical CT (n = 39) or pulmonary angiography (n = 1). Repeated Doppler US of the legs depicted one thrombus in the calf of three patients with normal results at helical CT that could have been responsible for PE. During 3-month follow-up, three patients experienced recurrent PE (one death, two recurrences). Therefore, PE occurred in six (5.4% [95% confidence interval, 1.3%, 9.7%]) of 112 patients with normal findings at helical CT who did not receive anticoagulant treatment. CONCLUSION: Findings at helical CT allowed accurate diagnosis of acute PE in patients with intermediate probability at V-P scintigraphy and without deep venous thrombosis at duplex sonography of the legs.

Acute Disease↗
PubMed1997

[Detection of renal artery stenoses by MRI with surface reconstruction. Value in patients with chronic renal failure].

Forty-three patients with renal artery stenoses were examined with time of flight MR angiography using maximum intensity projection and surface shaded rendering, and with digital substraction angiography. Sensitivity and specificity were 0.83 and 0.78 for main and secondary arteries, 0.87 and 0.84 for main arteries. In azotemic patients, the positive predictive value was estimated at 40%-70% and the negative predictive value at 95%-98%, while the prevalence of renal artery stenoses varied from 10% to 30%. These results validate MRI for the detection of renal artery stenoses in this population. Surface shaded display was more accurate than maximum intensity projection to reconstruct time of flight sequences and to grade renal artery stenoses.

Adult↗