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Biomedical subjects

A Heuck

Publications and source records attributed to A Heuck.

At least 19 recordsLinked to original sources
PubMed1998

Hybrid rendering of the cervico-cranial arteries using spiral computed tomography.

PURPOSE: The purpose of this study was to develop a shaded-surface and volume display (hybrid rendering method) of the whole vascular system of the cervico-cranial arteries using spiral computed tomography (SCT). MATERIALS AND METHODS: We examined 12 patients with anatomic abnormalities and pathological conditions of the arterial vascular system. The cervico-cranial arteries were segmented using an interactive threshold interval density volume-growing method and visualized with a color-coded shaded-surface display (SSD) rendering method. The adjacent bone structures were visualized using a transparent volume rendering method. RESULTS: In all cases, the entire volume of the vascular system of the cervico-cranial arteries and the anatomic abnormalities and pathological conditions could be visualized. CONCLUSION: Hybrid rendering of the circulation of the cervico-cranial arteries using image data sets from a subsecond spiral CT scanner is useful for the visualization of anatomical and pathological abnormalities and offer a promising minimally invasive alternative compared with other diagnostic procedures.

Adult↗
PubMed1997

[Initial experiences with contrast enhanced MR angiography after kidney and pancreas transplantation].

PURPOSE: The assessment of vascular complications by DSA in patients who have undergone kidney and pancreas transplantation is an invasive investigation and has the risk of nephrotoxicity caused by the iodinated contrast agent. The aim of this study was to compare the diagnostic value of noninvasive gadolinium--enhanced MRA with intraoperative and DSA results. PATIENTS AND METHODS: Eleven MRA investigations were performed in eight patients after kidney and pancreas transplantation. A fast T1-weighted 3D-gradient-echo sequence with short TR and TE was used in a dynamic technique including the three consecutive data acquisitions after a Gd-DTPA (Magnevist) injection. MRA was compared with intraoperative findings in all patients and with DSA in three patients. RESULTS: In the distal abdominal aorta, the internal and external iliac arteries, the main transplanted arterial vessels, and the arteries after first branching, high signal intensity was found. Assessment of renal and pancreatic parenchyma perfusion was possible in all patients. Venous transplant vessels could be depicted in four patients. CONCLUSION: Our initial experience with the MRA sequence used shows that this technique may be promising in the assessment of larger arterial transplanted vessels and kidney/pancreas parenchyma perfusion. Improvement of the MRA technique is necessary for transplanted venous vessels.

Angiography, Digital Subtraction↗
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

Imaging of the hand: degeneration, impingement and overuse.

Degenerative and overuse diseases as well as impingement syndromes of the hand are illustrated and discussed in this review article. Osteoarthritis of the interphalangeal joints as described by Heberden and Bouchard is a ubiquitous articular disease often associated with synovitis and erosive joint destruction. Osteoarthritis of the trapeziometacarpal joint is classified into four stages for proper indication of operation. Overuse can result in stenosing tenosynovitis around the wrist and in synovitis with or without impingement of the flexor or extensor tendons of the digitis or ruptures of the annular and cruciform pulleys. Although diagnosis of these entities is usually made by history and clinical investigation, ultrasound and MRI can be helpful tools in imaging of these diseases. Scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) are the characteristic degeneration pattern of the wrist and represent the degeneration mechanisms in scapholunate insufficiency and nonunion of the scaphoid. SLAC wrist is a gradual degeneration classified in three stages and found in posttraumatic scapholunate rupture, calcium pyrophosphate dehydrate deposition disease (CPPD), rheumatoid arthritis, neuropathic diseases, trauma, and beta 2-microglobulin associated amyloid deposition. Ulna impaction syndrome is increasingly recognized as a cause of ulnar sided pain and exhibits a characteristic MRI appearance.

Cumulative Trauma Disorders↗
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↗
PubMed1997

[Increased liver density in computed tomography as a result of anti-arrhythmia therapy with amiodarone].

PURPOSE: To assess whether the hepatic density on CT scans of patients receiving amiodarone therapy differs significantly from the hepatic density of a control group not receiving the drug. METHODS: Hepatic density was assessed by CT in 31 patients receiving amiodarone, 7 receiving short-term (12-14 days), 8 receiving mid-term (20-89 days) and 16 receiving long-term therapy (3-26 months), as well as in a control group of 15 patients. RESULTS: Mean liver density of all patients under amiodarone therapy (77.9 +/- 11.7 HU) was significantly higher (p < 0.005) than in the control group (56.6 +/- 2.8 HU). The smallest increase in density was found in patients with short-term therapy (64.8 +/- 3.4 HU; p < 0.05), the greatest increase in patients with long-term therapy (85.0 +/- 8.9 HU; p < 0.001). CONCLUSION: In patients receiving amiodarone therapy, a significantly increased hepatic density on CT scans is observed. This finding has to be considered as a differential diagnosis to other hepatopathies with increased density of the liver.

Adult↗
PubMed1997

[Lymph node staging in cervix carcinomas: the results of high-resolution magnetic resonance tomography (MRT) with a phased-array body coil].

PURPOSE: To determine the diagnostic value of high resolution MR imaging with a circularly polarised (c.p.) body phased-array coil for the staging of pelvic lymph nodes in cervical carcinoma. MATERIAL AND METHODS: 42 patients with histologically proven carcinoma of the cervix were studied on a 1.5 T scanner by using a c.p. body phased-array coil. The imaging protocol included T2-weighted turbo-spin-echo (TSE) and T1-weighted spin-echo sequences pre and post i.v. application of Gd-DTPA; slice thickness was 5-7 mm and pixel size 0.53 mm2. Lymph nodes with a diameter of > or = 8 mm were considered to have metastatic involvement. MR imaging results were compared with histopathologic findings. RESULTS: MR imaging showed enlarged lymph nodes (> or = 8 mm) in 16 of 18 patients with histologic proof of lymph node metastases (sensitivity 89%). In 22 of 24 cases MR findings were true negative (specificity 92%). Diagnostic accuracy was 91%. CONCLUSION: High-resolution MR imaging with a c.p. body phased-array coil provides high sensitivity, specificity, and diagnostic accuracy for pelvic lymph node staging in cervical carcinoma.

Adult↗
PubMed1997

[Parametrial infiltration of cervix carcinoma: diagnostic value of contrast-enhanced fat-suppressed T1-weighted SE sequences at 1.5 tesla].

PURPOSE: To determine whether contrast-enhanced and fat-suppressed sequences contribute to the MR imaging diagnosis of parametrial invasion. METHODS: 21 patients with carcinoma of the cervix were prospectively examined with a phased-array coil and a 1.5T MR-scanner using the following sequences: transverse T2-weighted turbo spin echo (T2-TSE), T1-weighted spin echo (T1-SE) and fat suppressed T1-weighted SE sequences before and after Gd-DTPA. The sequences were evaluated separately for the presence of parametrial invasion. Image quality and diagnostic confidence were classified on a scale of 0-10 (nondiagnostic-excellent). Findings were compared to the results of the pathohistological examination. RESULTS: Sensitivity, specificity and diagnostic accuracy were highest for T2-TSE sequences (100%, 79% and 86%, respectively). Contrast-enhanced T1-SE sequences with fat-suppression (71%, 79%, and 76%) showed no improvement compared to T2-TSE. Unenhanced fat-suppressed T1-SE (100%, 30%, and 56%) and unenhanced T1-SE (100%, 7%, and 38%) as well as contrast-enhanced T1-SE (86%, 20%, and 47%) were significantly worse than T2-TSE. With similar image quality (p < 0.05) diagnostic confidence was higher on T2-TSE than on any of the other sequences (p < 0.001). CONCLUSION: Considering the cost-effectiveness of the examination, for the MR diagnosis of parametrial invasion the use of fat-suppressed contrast-enhanced sequences can be abandoned in favour of T2-weighted TSE sequences.

Adult↗
PubMed1996

[MRI monitoring before, during and after interstitial laser-induced hyperthermia of benign prostatic hyperplasia. Initial clinical experiences].

PURPOSE: To assess the clinical value of MRI in patients with benign prostatic hyperplasia (BPH) before, during, and after interstitial laser-induced thermotherapy (LITT) of the prostate. METHODS: Ten patients with symptomatic BPH had MRI examinations of the prostate 48 h before and after LITT. Online monitoring with MRI at 1.5 T of interstitial Nd:YAG laser energy deposition in the prostate was performed in two patients, repeating a T1-weighted FLASH sequence (TR 100 ms, TE 5 ms, flip angle 90 degrees) every 20 s. Follow-up MRI examinations 2-3 weeks, 6-8 weeks, and 6-12 months after LITT were carried out in eight patients, using T2-weighted FSE images and contrast-enhanced T1-weighted SE images. RESULTS: The prostate was well delineated in all patients on T2-weighted FSE images, with a rather homogeneous peripheral gland and an inhomogeneous central gland. Volume measurements yielded reproducibilities of 3.2%-4.7%. Signal intensity in the FLASH sequence decreased during LITT, both in the prostate in vivo and in specimens of bovine prostate and seminal vesicles in vitro, with signal developments running in parallel. Areas of energy deposition and signal alteration were not sharply delineated. The latter margin of the laser-induced lesions could not be predicted from the FLASH images, while the tip of the laser fibre was easily recognized. Contrast-enhanced T1-weighted MR images immediately after LITT clearly demarcated low signal intensity laser lesions from high signal intensity surrounding prostate tissue. Follow-up examinations showed a decrease of 20% of prostate volume over a period of 6-12 months after LITT. Correlation between prostate volume development and lesion volume alteration was 0.85-0.90 (P = 0.002-0.007) at all follow-up times. CONCLUSIONS: MRI allows rather precise recognition of intraprostatic alterations after LITT, including volume changes over a period of up to 1 year after therapy that can be predicted immediately after LITT. While laser energy deposition in the prostate can be monitored by MRI with T1-weighted FLASH sequences as a function of temperature alteration, it is not possible to determine the lesion margins immediately from the FLASH images. Online temperature development map generation will be necessary to influence on-going LITT procedures with MRI.

Aged↗
PubMed1995

[Spontaneous hemothorax in dermatomyositis and long-term glucocorticoid treatment].

A 65-year-old woman with dermatomyositis for which she had been treated for ten years with prednisone (latterly 15 mg daily) suddenly experienced severe pain in the left thoracolumbar region. Cardiovascular, pulmonary and vertebral causes of the pain were excluded. But serological tests indicated inflammatory disease and the haemoglobin concentration was low (10.4 g/dl). Left pleural effusions were repeatedly aspirated and some haemorrhagic fluid obtained (haematocrit 0.31 in blood, 0.28 in the pleural effusion). Five days after admission her cardiovascular status became unstable and she developed respiratory failure (haemoglobin 7.6 g/dl). Chest radiograph showed increased pleural effusion. Subsequent thoracotomy revealed a left coagulothorax which was removed and flushed. During this procedure severe bleeding occurred from a covered perforation of the descending aorta, 1.5 x 1.5 cm in size. Although the aortic wall was thin, there was no aneurysm but arteriosclerotic changes and an external erosion near an abscessing mediastinitis, originating from a chronic purulent pleuritis and bronchopneumonia. The severe blood loss caused circulatory failure from which the patient could not be resuscitated.

Aged↗
PubMed1995

[MR functional diagnosis of the cervical spine after strain injury].

50 patients with a history of distortion injury of the cervical spine were examined with static and functional MRI. Functional MRI consisted of different patient's positions from maximal extension to maximal flexion (30 degrees, 0 degrees, 25 degrees, 40 degrees, 50 degrees). T2*-weighted gradient echo sequences were performed in a sagittal view for the different positions. Ligamentous instabilities and disc protrusions were seen only in functional MRI in 17 patients. These findings correlated with the neurological symptoms. Two patients were treated by operative fusion because of these findings.

Adult↗
PubMed1995

Reproducibility of quantitative, spirometrically controlled CT.

Quantitative spirometrically controlled computed tomography (with 1-mm-thick sections) was performed twice (with a 5-minute break) in 24 adult patients with pulmonary disease to objectively evaluate parenchymal changes in the lung. Twelve measurements of attenuation were made on apical, carinal, and basal scans (right, left, total of each level, total right, total left, total of all three scans), obtained at 50% vital capacity. Since differences in measurements between the first and second examination were not significant, the method provides highly reproducible results.

Adult↗
PubMed1995

[Magnetic resonance tomography in trauma of the knee joint].

Technical improvements of MRI have significantly improved the visualization of joints. New sequences and experience with MRI has lead to increased sensitivity and specificity of internal joint lesions. For the first time, contusions of the subchondral bone which are prognostically significant for the developing of chondral lesions can be identified. To date, no other tests are available to identify such lesions. This review article outlines the current value of MRI for evaluating post-traumatic knee joint injuries.

Bone Marrow↗