Biomedical subjects

H Bonél

Publications and source records attributed to H Bonél.

13 recordsLinked to original sources

PubMed2001

[Effect of muscle activity on the 3-dimensional movement pattern of the shoulder. Study with open MRI].

The objective of this study was to analyze the influence of shoulder muscle activity on the three-dimensional motion pattern of the shoulder girdle in the living. 14 healthy volunteers were investigated with an open MRI system at 60-120 degrees abduction--with and without activity of the shoulder abductors. The 3D motion pattern of the humerus, scapula, clavicle and M. supraspinatus were computed. Under muscle activity, the glenoid demonstrated a slightly reduced elevation at 60 degrees of abduction (20.5 degrees +/- 8.2 degrees vs. 23.1 degrees +/- 6.3 degrees; not significant), and at 120 degrees a significantly higher degree of rotation under muscle activity (43.3 degrees +/- 8.6 degrees vs. 36.1 degrees +/- 5.2 degrees; p < 0.01), whereas at 90 degrees no difference was observed. This caused a significant reduction of the scapulo-humeral rhythm at 120 degrees (2.6 vs. 1.5; p < 0.01), a significant increase of the supraspinatus angle (123.3 degrees +/- 6.7 degrees vs. 117.3 degrees +/- 6.5 degrees; p < 0.05) as well as a reduction of the supraspinato-humeral relationship (1.0 vs. 0.97). The study demonstrates that muscle activity leads to an alteration of shoulder girlde motion patterns at higher degrees of abduction, with increased rotation of the scapula, an altered spatial relationship between the supraspinatus and humerus.

Adult↗

PubMed2000

Differentiation of malignant from benign solitary pulmonary lesions using chest radiography, spiral CT and HRCT.

OBJECTIVE: The aim of this prospective study was to summarize all of the qualitative and quantitative imaging criteria for the differentiation of solitary pulmonary lesions (SPLs) as malignant (MSPLs) or benign (BSPLs) described in the literature and to critically analyze the different characteristics in order to evaluate their clinical importance and usefulness as criteria for a discrimination during the primary diagnostic assessment of SPLs using chest radiography, spiral computed tomography (SCT) and high-resolution computed tomography (HRCT). MATERIALS AND METHODS: SPLs were examined, evaluated and then completely removed by surgery in 104 consecutive patients (MSPLs n=81, BSPLs n=23). No SPL was excluded by size. Chest radiography was performed with frontal and lateral views, SCT was carried out with a slice thickness of 8 mm and HRCT with a slice thickness of 1 mm and a 12-cm field of view. RESULTS: All the characteristics which enabled a reliable differentiation of MSPLs from BSPLs were characteristics which were observed significantly more frequently in MSPLs than BSPLs. Useful characteristics for the differentiation of MSPLs from BSPLs (1) using chest radiography were the indistinct edge (P<0.0001) and a ground-glass opacity of the lung parenchyma adjacent to the SPL (P<0. 05); (2) using SCT the presence of spicules (P<0.0005), the vessel sign (P<0.0005), necrotic areas (P<0.001), spicules extending to the visceral pleura (P<0.005), circumscribed pleural thickening (P<0. 005), inhomogeneity (P<0.01), a ground-glass opacity of the lung parenchyma adjacent to the SPL (P<0.01), the lesion density (P<0.05), pleural retraction (P<0.05) and the bronchus sign (P<0.05); and (3) using HRCT the presence of spicules (P<0.00005), spicules extending to the visceral pleura (P<0.0005), the vessel sign (P<0.0005), pleural retraction (P<0.001), circumscribed pleural thickening (P<0. 001), the bronchus sign (P<0.005), a ground-glass opacity of the lung parenchyma adjacent to the SPL (P<0.01), the lesion density (P<0.05) and the length of spicules (P<0.05). Using any one of the characteristics with a significance level of P<0.01, the identification of MSPLs (1) using chest radiography showed a sensitivity of 64.2% and a specificity of 82.6% (accuracy of 68.3%); (2) using SCT a sensitivity of 88.9% and a specificity of 60.9% (accuracy of 82.7%); and (3) using HRCT a sensitivity of 91.4% and a specificity of 56.5% (accuracy of 83.7%). CONCLUSIONS: Using chest radiography, SCT and HRCT, a precise morphological assessment of the periphery of the pulmonary lesion and the adjacent visceral pleura is necessary to distinguish MSPLs from BSPLs. In this respect SCT and HRCT are useful in differentiation of MSPLs from BSPLs. However, metastases strongly resembled benign lesions in terms of size and edge type and chronic inflammatory pseudotumors as a group mimic MSPLs.

Diagnosis, Differential↗

PubMed2000

[A new in vivo technique for 3-dimensional analysis of the translation of femoral condyles and the menisci responding to antagonistic muscle forces].

The aim of our study was to develop a 3-D MR-based technique for the analysis of meniscal and femoral translations during flexion of the knee, and under the influence of antagonistic muscle forces in healthy subjects. In an open MR system, 5 knees were examined at 30 degrees and 90 degrees flexion using a T1-weighted 3-D gradient echo sequence. A force of 30 Newtons, first in the extending and then in the flexing direction, was applied to the distal lower leg. After three-dimensional reconstruction, the minimal distances between the centre of the tibial plateau and the posterior edge of the menisci and femoral condyles were determined. At 30 degrees flexion, the minimum distance for the meniscus was larger medially than laterally (23.2 +/- 1.8 mm vs. 16.2 +/- 3.3 mm), and this also applied to the condyles (25.1 +/- 1.5 vs. 19.0 +/- 3.0 mm). During flexion to 90 degrees, a posterior translation of 0.5 +/- 0.2 mm was observed for the lateral, and of 3.4 +/- 1.2 mm for the medial, meniscus. The condyles demonstrated a different posterior translation (lateral 2.2 +/- 0.56 mm; medial 1.8 +/- 1.9 mm). No obvious differences were found between extension and flexion muscle activity for the different positions of the knee. In the present study, a new 3-D technique is presented for the analysis of the femoral and meniscal translation at various positions of the knee, and under muscle activity. The results suggest different translation for the menisci and condyles.

Adult↗

PubMed1999

Speech processing in radiology.

The goal of this study was to evaluate the recognition rate, learning potential and amount of time needed to complete a report with the Philips speech recognition system SP 6000 (Philips, Best, The Netherlands). Four radiologists dictated reports of interventional radiology, MRI examinations of the musculoskeletal system and CT examinations of the thorax and abdomen with the Philips system using the German language. The recognition rate of each report and improvement rate after each learning phase of the Philips system was assessed. The time needed to complete a report using the Philips system was then compared with the time needed to complete a report using the tape-based system via a time analysis. The average recognition rate for the four radiologists using the Philips system was 79.6 %, which improved to 92.5 % after the third adaptation. Initially, the average time demand to dictate and correct one report was approximately 16.8 min, but this time decreased to 8.1 min after the third adaptation. In contrast, only 3. 6 min were needed to dictate and correct one report using the tape-based system. However, with the speech recognition system, dictation, correction and transcription of the report can be completed within 15 min, whereas with the tape-based system, it takes nearly 1 day. With the Philips system, speech recognition can reach as high as 95 % since each adaptation of the system improves the recognition rate by approximately 5 %. While the Philips system is associated with longer dictation times than the tape-based system, turn-around time for a complete report is substantially shorter with the Philips system than the tape-based system.

Computer Communication Networks↗

PubMed1999

Evaluation of the middle and inner ear structures: comparison of hybrid rendering, virtual endoscopy and axial 2D source images.

Recent developments in 3D reconstructions can enhance the quality and diagnostic value of axial 2D image data sets with direct benefits for clinical practice. To show the possible advantages of a hybrid rendering method [color-coded 3D shaded-surface display (SSD)- and volume rendering method] with the possibility of virtual endoscopy we have specifically highlighted the use in relation to the middle and inner ear structures. We examined 12 patients with both normal findings and postoperative changes, using image data sets from high-resolution spiral computed tomography (HRSCT). The middle and inner ear was segmented using an interactive threshold interval density volume-growing method and visualized with a color-coded SSD rendering method. The temporal bone was visualized using a transparent volume rendering method. The 3D- and virtual reconstructions were compared with the axial 2D source images. The evaluated middle and inner ear structures could be seen in their complete form and correct topographical relationship, and the 3D- and virtual reconstructions indicated an improved representation and spatial orientation of these structures. A hybrid and virtual endoscopic method could add information and improve the value of imaging in the diagnosis and management of patients with middle or inner ear diseases making the understanding and interpretation of axial 2D CT image data sets easier. The introduction of an improved rendering algorithm aids radiological diagnostics, medical education, surgical planning, surgical training, and postoperative assessment.

Adult↗

PubMed1998

Comparison of sequences for depicting bone marrow alterations in osteomyelitis applied in a low field strength magnetic resonance imaging system.

OBJECTIVE/PATIENTS: To investigate the efficacy of standard sequences of a low field system for the detection of osteomyelitis, we tested T1wI pre and post i.v. contrast, T2w and fat suppressed IR sequences. DESIGN: On the basis of clinical and laboratory evidence, pathology reports, and three phase granulocyte scintigraphy, osteomyelitis was diagnosed in 18 of 21 patients with Charcot's joints. A consecutive low and high field magnetic resonance (MR) scan confirmed osteomyelitic bone marrow changes in the same osseous regions. These 18 diabetic patients were then studied on a 0.2 Tesla dedicated MR system (Esaote ArtoScan) using T1wI (SE: relaxation time (TR) 520/echo time (TE) 24: axial and coronal) before and after i.v. application of 0.1 mmol/l Gd-DTPA/kg BW, T2w imaging (TSE: TR 3500/TE 80 or TR 2000/TE 120: axial), and fat suppressed inversion recovery (IR) imaging (short tau inversion recovery (STIR): TR 3000/TE 30/TI 80 or inversion recovery gradient echo (IRGE)/fat suppressed IRGE (GEFS): TR 1000/TE 16m 80: coronal). RESULTS: The SE T1w sequence showed a significantly higher contrast-to-noise ratio (CNR) before administration of i.v. contrast. The TSE T2w pulse sequence demonstrated bone marrow changes superiorily utilizing a TE of 120 ms (CNR = 16.5+/-2.7 compared to 5.5+/-2.5 with TE = 80 ms). The IRGE showed a higher CNR than the standard STIR (CNR = 19.2+/-2.5 compared to 12.4+/-2.9). CONCLUSION: Fat suppressed IRGE imaging and longer TE in T2w TSE sequences result in a significantly better CNR in osteomyelitis. This way, using optimized sequences, low field systems are apt to depict bone marrow changes in the course of osteomyelitis.

Adolescent↗

PubMed1998

[Contrast medium studies of the venous system].

PURPOSE: To give an overview of various diagnostic techniques and indications for phlebography in different parts of the body. METHODS: Procedures of conventional phlebography of the lower and upper extremity and cavography are described and their indications in comparison to alternative techniques are discussed. The literature is reviewed with regard to specific advantages and disadvantages of the different methods. RESULTS: Conventional phlebography with iodine contrast media is still considered to be the gold standard in many regards. The diagnosis of acute and chronic thrombotic disease, venous vascular occlusions, hemodynamic malfunctions and anatomic variants of the venous system can readily be established with contrast phlebography. DISCUSSION: Main disadvantages of contrast studies of the venous system are radiation exposure and adverse effects of contrast media. Non-invasive methods such as ultrasound and MR-phlebography are becoming more and more popular and may replace venography. Other techniques such as CT-phlebography and the use of CO2 as contrast medium are under investigation. The latter can be indicated in the case of contraindications against iodine contrast media. CONCLUSION: When choosing diagnostic methods for the venous system, their sensitivity and specificity for specific diagnoses and vascular territories have to be balanced against the risks and disadvantages.

Contrast Media↗

PubMed1998

[Comparison of a high-end ultrasound system with a spiral CT scanner in screening for liver metastases].

AIM: To assess prospectively the sensitivity of a high-end ultrasound system in comparison to a spiral computed tomographic scanner in screening for liver metastases. METHOD: 88 consecutive patients with malignant diseases were examined using gray-scale sonography and contrast enhanced two-phase spiral computed tomography during arterial dominant and portal venous phase. For both methods all focal lesions of the liver were reported. RESULTS: 99 focal lesions of the liver were detected by gray-scale sonography and/or two-phase spiral computed tomography. The sensitivity for gray-scale sonography was 93.9% (93 of 99 lesions) and for two-phase spiral computed tomography (71.7% (71 of 99 lesions), respectively. CONCLUSION: Screening for liver metastases should be performed by using a diagnostic method with a high sensitivity. Gray-scale sonography with a high-end ultrasound system fulfill' these requirements.

Adult↗

PubMed1997

[Acceptance of high field whole body MRI equipment, open MRI systems dedicated extremity scanners by patients].

To our knowledge no comparative studies investigating patients' acceptance of different MR systems have been published. We therefore studied a number of subjective criteria to evaluate both patients' acceptance of and subjective conditions during magnetic resonance imaging (MRI) studies. MRI studies were performed using four separate systems. Two were conventional body MR systems operating at 1.0 or 1.5 Tesla, another was a 0.2 Tesla open whole-body MR system, and the last was a 0.2 Tesla MR system dedicated to the study of extremities. Forty patients for each MR system (total of 160 patients) participated in a standardized, written interview focusing on aspects of their subjective condition, including their perception and acceptance of different factors relevant to the study on respective MR systems. The patients' subjective condition and acceptance was predominantly positive for all MR systems. Differences between MR systems were noted with respect to noise, width of patient gantry, comfort of patient positioning and degree of well-being. Such differences, however, do not lend preference to the use of one particular type of MR system. Therefore, the choice of MR system should be based on the technical features required for the intended studies.

Adolescent↗

PubMed1997

[Examination of the hand and wrist joints with a dedicated low-field MRI device].

Purpose of this study was to evaluate the diagnostic value of a low field dedicated MRI system in hand and wrist imaging. All 308 exams of the hand and wrist, that were performed on a low-field dedicated MRI system (Artoscan, Esaote Biomedica, Italy) in our institution in 1996, and high-field MRI exams performed in addition as part of the diagnostic work-up, were evaluated and correlated to final operative (n = 64) and histologic (n = 12) reports. 90% of all low-field MRI scans stated a diagnosis according to clinical suspicion. In 62% the clinical question was answered, and in 26% additional pathologies were identified. An MR-diagnosis completely different from the clinical suspicion was stated in 2%. High field exams contributed additional information in 6 of 36 patients. In 3 patients a tumor was not shown completely in the limited field-of-view of the dedicated low-field MRI-system. Frequency-selective fat-suppression pulse sequences and a better spatial resolution were the reasons for the additional information obtained in the other three patients. Low-field dedicated MR-imaging is a valuable method in the extensive work-up of the hand and wrist. Osseous, ligamentous and tendinous pathologies are well depicted. Large or infiltrative tumors should be referred to a high-field system.

Adolescent↗

PubMed1997

[MRI of fingers in systemic scleroderma. Initial results with contrast-enhanced studies using a dedicated MRI system].

PURPOSE: To estimate disease activity in patients with systemic sclerosis using contrast-enhanced MRI of the skin. MATERIAL AND METHODS: In a pre-study, sequences of a low-field (0.2 T) scanner (Artoscan, Esaote, Genova, Italy) were optimized for detection of intravenous contrast (0.1 mmol/l Gd-DTPA) in six patients with the autoimmune disease systemic scleroderma. Based on the results of the pre-study, 17 patients with scleroderma (7 sclerotic/10 active inflammatory disease) were scanned using gradient-spoiled 3D GRE sequences (FA 90 degrees, TR 100 ms, TE 18 ms), which had been established as most sensitive for intravenous contrast. Contrast enhancement of the skin was determined quantitatively by contrast-to-noise ratios (CNR), comparing post- to pre-contrast and dynamic scans (for 6 min, 1 acquisition/min). Patients in the chronic state with sclerodactylia and active inflammation of the hands were considered separately and compared to a control group (n = 10) matched according to age. RESULTS: CNR increase after intravenous contrast was significantly higher in patients with active disease (86 +/- 16% increase) than sclerosing disease (29 +/- 3%, p < 0.05) and the control group (4 +/- 2%, p < 0.05). The dynamic examination showed a significantly slower decrease after the peak rise in the first minute in patients with active disease (CNR 15.4 +/- 0.7 to 14.2 +/- 1.4) than in those with chronic disease (14.1 +/- 0.5 to 11.3 +/- 0.9, p < 0.05). DISCUSSION: Capillary leakage is the most likely explanation for the increased enhancement in patients with active scleroderma. Using sequences optimized for contrast detection, disease activity in the course of scleroderma and response to therapy can be determined by MRI in the future.

Adult↗

PubMed1997

Imaging in sports medicine: hand and wrist.

Sports-related injuries of the hand and wrist include lesions of the bones, joints, ligaments, tendons and muscles. In many cases, radiologic imaging procedures are indispensible for the depiction, localization and accurate diagnosis of these lesions. This article reviews the role and potential of current imaging modalities such as conventional radiography, fluoroscopic examinations, arthrography, computed tomography (CT), ultrasound, and magnetic resonance (MR) imaging for the diagnostic work-up of typical osseous and soft tissue injuries in sports medicine.

Athletic Injuries↗

PubMedDate not supplied

Sex-specific differences of subacromial space width during abduction, with and without muscular activity, and correlation with anthropometric variables.

The objectives of this study were to determine sex-specific differences of the subacromial space width during active and passive arm abduction and to analyze the correlation of this space with general and regional anthropometric variables. Fourteen healthy subjects (7 men, 7 women) were examined with an open magnetic resonance system at 30 degrees and 90 degrees of abduction (with and without muscle activity). After 3-dimensional reconstruction, the minimal acromiohumeral distance, the glenoid size, and the humeral head radius were determined. At 30 degrees of abduction, a significant difference of the acromiohumeral distance was observed between men (8.18 +/- 1.0 mm) and women (6.98 +/- 0.75 mm) (P < .05), but not at 90 degrees (6.7 +/- 2.0 mm versus 5.9 +/- 1.0 mm) or under muscle activity (4.9 +/- 2.4 mm versus 3.5 +/- 2.1 mm). Significant correlations between the acromiohumeral distance and anthropometric variables were found at 30 degrees of abduction (r = 0.48 to 0.72), but not at 90 degrees, with or without muscle activity (r = 0.21 to 0.55). The results demonstrate that at physical rest, the subacromial space width is dependent on sex, but the interindividual variability increases substantially during abduction and under muscle activity.

Adult↗