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Biomedical subjects

W Heindel

Publications and source records attributed to W Heindel.

At least 127 records · Page 7Linked to original sources
PubMed1996

Angiographic detection of gastrointestinal bleeding. An experimental comparison of conventional screen-film angiography and digital subtraction angiography.

RATIONALE AND OBJECTIVES: The authors experimentally assess and compare the detection limit of gastrointestinal bleeding in digital subtraction angiography (DSA) and conventional screen-film angiography. MATERIALS AND METHODS: Arterial blood flow was simulated using a tube model in which bleeding was imitated by exudation of liquid containing contrast material. Gut peristalsis was imitated using silicone tubes filled with air and liquid. Images were acquired by DSA and conventional screen-film angiography. The iodine concentration was increased in increments from 1 mg I/mL, with and without simulated peristalsis, and with both free and circumscribed extravasation of contrast material. RESULTS: The detection limit for free extravasation in DSA was 1 mg I/mL without peristalsis and 60 mg I/mL with peristalsis. The corresponding figures for circumscribed extravasation were 1 mg I/mL and 34 mg I/mL. The detection limit for free extravasation in screen-film angiography was 172 mg I/mL both with and without simulated peristalsis. Circumscribed extravasation was detected at 9 mg I/mL without peristalsis and 7 mg I/mL with peristalsis. CONCLUSION: Digital subtraction angiography is the more sensitive angiographic technique for detection of gastrointestinal bleeding and is superior to conventional screen-film angiography, provided that it is performed with adequate parasym-pathicolysis and suspended respiration. Only when these requirements cannot be achieved is screen-film angiography advantageous.

Angiography↗
PubMed1996

Recurrent bleeding of angiomyolipomas in tuberous sclerosis.

The diagnostic and therapeutic problems of renal hamartomas are illustrated by a case of recurrence of bleeding angiomyolipomas associated with tuberous sclerosis. Ultrasound and computed tomography provide clear evidence of lipomatous formation while, in rare instances, angiography can demonstrate the existence of multiple vascular tumor compartments. In view of the risk of bleeding, multiple or very large angiomyolipomas should be treated by interventional radiology in the form of superselective tumor embolization or by the most conservative surgery possible.

Adult↗
PubMed1996

[Infections of the cervical spine].

Diagnosis of infectious disease of the spine in an early stage ist difficult. Conventional X-ray examinations, often used as a basic screening study, will show the characteristic narrowing of the intervertebral disc space and the osteolytic and sclerotic changes in the adjointing vertebra only after two to eight weeks. Magnetic resonance imaging (MRI) has a sensitivity equivalent to bone scintigraphy and, due to its superior delineation of anatomic details, MRI has become the method of choice not only for the assessment of location, extent, and associated lesions in infectious bone disease, but also in the diagnosis of intradural infections including myelitis. MRI examination in the assessment of a successful therapy or osteomyelitis of the spine aims for the detection of regression of bone marrow edema, reappearance of fatty marrow, and less pronounced contrast enhancement. Computed tomography (CT) is mainly used for image-guided biopsy to obtain specimen for microbiologic culture or for the placement of a percutaneous drainage.

Abscess↗
PubMed1996

[Local fibrinolytic therapy of arterial occlusions of the lower extremity: initial success and clinical outcome].

INDICATIONS: The efficiency of local fibrinolysis therapy in patients with chronic and acute peripheral arterial occlusions of the lower extremities has been investigated. PATIENTS AND METHODS: A total of 33 patients were examined following a local fibrinolysis therapy (in 14 cases with supplementary percutaneous transluminal angioplasty) for chronic or acute peripheral arterial occlusion of the lower extremities. The success of the intervention was first evaluated by angiography and then by subsequent controls by means of treadmill ergometry. RESULTS: A primary intervention success was achieved in 75.8% (25 of 33 patients) of the cases. In 18.2% (6 of 33 patients) a vascular surgical operation was required within 30 days of the intervention (5 therapy failures, 1 complication of the intervention). In two further patients, vascular surgery was necessary after five or six months. In 22 of the 25 successfully treated patients (92%), the Fontaine stage was reduced by at least one step after an average of 7.6 (range: 1 to 30) months. CONCLUSIONS: Local lysis with or without PTA represents an effective alternative therapy to vascular surgery for the treatment of peripheral arterial occlusions in not immediately endangered lower extremities. On the basis of our results and a survey of the literature, an aid for selecting therapeutic measures for patients with arterial occlusion of the extremities is presented.

Adult↗
PubMed1995

Magnetic resonance imaging and mood disorders. Localization of white matter and other subcortical abnormalities.

BACKGROUND: Recent reports in the literature document an association between focal white matter abnormalities in bipolar as well as unipolar mood disorder. The importance of this finding and other associated anatomic differences is uncertain. METHODS: We examined the volume of abnormal white matter and other brain volumes using quantitative magnetic resonance imaging analysis. We explored the relationship of these variables with diagnosis, cognitive function, and clinical variables in 36 patients with bipolar disorder, 30 patients with unipolar disorder, and 26 control subjects who were free from significant medical and neurologic illness. RESULTS: Younger patients with bipolar disorder (but not similarly aged patients with unipolar disorder or controls) have an increased volume of abnormal white matter. Data also indicate that the total volume of abnormal white matter may be associated with increased cognitive impairment, increased rate of psychiatric illness in the family, and onset after adolescence. CONCLUSION: Patients with bipolar disorder demonstrate a pattern of subcortical brain morphologic abnormalities and cognitive impairment.

Adult↗
PubMed1995

Positron emission tomography and magnetic resonance spectroscopy of cerebral glycolysis in children with congenital lactic acidosis.

Congenital lactic acidosis with neurological symptoms may be due to a variety of disorders of energy metabolism. We investigated whether positron emission tomography (PET) and proton magnetic resonance spectroscopy (1H MRS) are capable of demonstrating specific changes to facilitate diagnosis. A corresponding increase of cerebral lactate (with MRS) and rate of glycolysis (with PET) was observed in 2 children with biochemical evidence of defective mitochondrial respiration. No such increase was noted in a child with lactic acidosis due to stress and exercise but normal respiratory chain activity, and in a control case with an epilepsy syndrome without evidence of primary changes of energy metabolism. The results suggest that defects of oxidative phosphorylation may cause a massive increase of glycolysis to cover energy requirements, with corresponding accumulation of lactate in brain tissue. This mechanism can now be demonstrated in vivo and, with further experience, may potentially be used as a diagnostic marker of respiratory chain disorders in brain tissue.

Acidosis, Lactic↗
PubMed1995

MR pulsatility measurements in peripheral arteries: preliminary results.

Phase contrast flow velocity measurements were performed in six healthy volunteers and 30 patients with arteriosclerotic disease. The iliac arteries were investigated in 8 cases and the femoral arteries in 28 cases. In the first 24 patients, 16 evenly distributed data sets were acquired during one cardiac cycle. In the last 12 patients, a trigger pulse followed by the acquisition of 30 evenly distributed data sets was applied every second heart beat. This procedure allowed data to be acquired over a full heart cycle without any acquisition gap. The measured flow velocities were displayed as function of time. Systolic acceleration, postsystolic deceleration and pulsatility of flow velocity were calculated and compared with stenosis grades determined from DSA angiograms. Flattening of the flow velocity patterns was found to correlate with the local severity of arteriosclerotic disease.

Adult↗
PubMed1995

Proton magnetic resonance spectroscopy reflects metabolic decompensation in maple syrup urine disease.

Using localized proton magnetic resonance spectroscopy (1H-MRS), accumulation of branched-chain amino acids (BCAA) and their corresponding 2-oxo acids (BCOA) could be non-invasively demonstrated in the brain of a 9-year-old girl suffering from classical maple syrup urine disease. During acute metabolic decompensation, the compounds caused a signal at a chemical shift of 0.9 ppm which was assigned by in vitro experiments. The brain tissue concentration of the sum of BCAA and BCOA could be estimated as 0.9 mmol/l. Localized 1H-MRS of the brain appears to be suitable for examining patients suffering from maple syrup urine disease in different metabolic states.

Adolescent↗
PubMed1995

Diagnostic performance of digital subtraction angiography (DSA) and magnetic resonance angiography (MRA): preliminary results in vascular occlusive disease of the abdominal and lower-extremity arteries.

Fifty-nine patients with occlusive disease of the aorto-iliac and femoro-popliteal arteries were investigated prospectively by intravenous (IV) or intraarterial (IA) digital subtraction angiography (DSA) and magnetic resonance angiography (MRA). This was accomplished using a two-dimensional (2D) Inflow- (59 patients) and a 2D Phase Contrast- (RSE--rapid sequential excitation) sequence (29 patients). The spectrum of pathology included stenoses < 50%, stenoses 50-89%, stenoses 90-99%, occlusions, aneurysms and status following reconstructive surgery. MRA- and DSA-examinations were evaluated by four radiologists. The diagnoses were made by consent decisions of a radiologist and a vascular surgeon based on clinical and radiological findings. Diagnostic performance of IA-DSA was superior to all other imaging modalities. Vascular delineation of 2D Inflow-MRA was comparable to that of IV-DSA. The image quality of RSE-MRA was not adequate for diagnosis. In conclusion, 2D Inflow-MRA is a promising method for evaluating abdominal and peripheral arteriosclerotic disease. Interpretation of MR-angiograms, however, requires profound knowledge of MRA-techniques, X-ray angiography and hemodynamics.

Adult↗
PubMed1995

[Peripheral occlusive arterial diseases: comparison of diagnostic value of MRA and DSA].

MATERIAL AND METHODS: In 59 patients with arterial flow disturbances 2-D inflow sequence of the abdominal and lower leg arteries were prospectively obtained on a 1.5 T MR-imager and were compared with additional DSA examinations. Supplementary Phase Contraste RSE ("Rapid Sequential Excitation") sequences were carried out in 29 patients. MRA and DSA angiograms were evaluated in random order by 4 readers using a questionnaire. The assessment of image quality were evaluated by variance analysis. Diagnostic performance of MRA and DSA was assessed by comparison of the readers' diagnostic assessments with reference diagnoses established by a radiologist and a vascular surgeon with full knowledge of all data concerning a patient. Image quality of inflow MRA was considered inferior to i.a. DSA (p < 0.001) and comparable with i.v. DSA (p = 0.1361). Image quality of RSE-MRA was inadequate (p < 0.001). Correspondingly, i.a. DSA was the superior and RSE-MRA the inferior imaging technique. The accuracy of inflow MRA in determining stenosis grade was 66% and that of RSE-MRA 59%.

Aged↗
PubMed1995

[A comparison of NMR tomography and arthrography in functional disorders of the temporomandibular joint].

PATIENTS AND METHODS: 31 patients with clinically diagnosed dysfunction of the temporomandibular joint (TMJ) were examined by magnetic resonance imaging (MRI; 1.5 Tesla, TR/TE 600/30) in closed and open mouth position and functional arthrography with digital image recording. RESULTS: Both methods agreed in the evaluation of the disc position. In 23 joints with displaced disc reposition was found in 11 cases and in 14 cases using MRI or arthrography, respectively. MRI proved to be superior in the diagnosis of sideways disc rotations. Joint hypermobility, eccentric disc displacement (n = 4) and perforation (n = 3) were shown by functional arthrography. Due to the good demonstration of osseous, muscular and discoligamentous structures, MRI as a noninvasive imaging modality is the method of choice for TMJ evaluation. Arthrography can be advantageous in complex functional disturbances or if MRI and clinical findings are inconclusive. The clinical diagnosis of disc displacement was found to be accurate in only 68% of the cases.

Adolescent↗
PubMed1995

Metabolic changes in acute and subacute cerebral infarctions: findings at proton MR spectroscopic imaging.

PURPOSE: To analyze the advantages of proton magnetic resonance (MR) spectroscopic imaging in the evaluation of acute and subacute cerebral infarcts. MATERIALS AND METHODS: Metabolite maps of choline-containing compounds, total creatine consisting of creatine and phosphocreatine, N-acetyl aspartate (NAA), and lactate were obtained in 23 patients with acute and subacute cerebral infarctions 1-35 days after onset of symptoms. Maps were obtained with a 1.5-T MR system with 32 x 32 phase-encoding steps. RESULTS: Distinct abnormal metabolite distributions could be detected in all lesions larger than 1 cm in diameter. In the center of infarcts with a diameter larger than the section thickness of 2 cm, NAA values decreased to 20% +/- 8 compared with contralateral brain as early as 1 day after onset of symptoms (P < .0001). Choline was reduced to 67% +/- 30 (not significant) and creatine to 51% +/- 22 (P = .0025). Large amounts of lactate were detected in all acute infarcts. Choline, creatine, and lactate values declined during the first 5 weeks after stroke. CONCLUSION: MR spectroscopic imaging allows visualization of metabolic changes in stroke with a reasonable spatial resolution.

Acute Disease↗
PubMed1995

Cine phase contrast angiography of normal and diseased peripheral arteries. Preliminary results.

Cine phase contrast angiography (PCA) is a modified MR phase contrast sequence that acquires up to 22 coronal phase images per mean cardiac cycle. The ability of the sequence to visualise local haemodynamics was investigated in 7 normal volunteers and 9 patients with flow disturbances of the peripheral arteries using a 1.5 T imager. Functional flow information provided by coronal cine PCA was correlated with quantitative data obtained by MR flow measurements and vessel morphology confirmed by conventional angiograms. Due to the yet suboptimal image quality, an aortic dissection and 1 of 4 aneurysms could not be depicted morphologically. The temporal pattern of arterial perfusion in cine PCA corresponded with flow velocity versus time data provided by quantitative MR flow measurements. Accuracy and time resolution of cine PCA was thus sufficient to provide functional information on the severity of occlusive vascular disease.

Adult↗
PubMed1995

[Spectroscopic imaging of the brain. Examination technique and clinical applications].

PURPOSE: MR spectroscopy allows the acquisition of a two-dimensional array of spatially resolved proton spectra of the human brain, known as MR spectroscopic imaging. Here the examination protocol and clinical applications in focal brain lesions are presented. METHOD: An array of data is acquired from a tissue slice positioned in the brain. These data can be presented as a set of spectra, in which each spectrum is allocated to a specific position in the sample, or as a set of images or "metabolite maps". RESULTS: The NAA signal typical for neuronal tissue is decreased in the centre of brain tumours as well as in brain infarcts. The intensity of the choline signal is increased in solid tumour tissue, whereas it is reduced in infarcts. CONCLUSION: Spectroscopic imaging reveals metabolite alterations in and around focal lesions. The spatial resolution of spectroscopic imaging enables matching with other macro-morphological or functional imaging methods like positron emission tomography.

Adult↗
PubMed1994

[CT and MRT in progressive multifocal leukoencephalopathy (PML)].

Radiological findings and course of progressive multifocal leukoencephalopathy in 14 patients (1 woman, 13 men; 13 HIV seropositive, 1 chronic lymphatic leukaemia) were analysed retrospectively and correlated with clinical symptoms. A total of 21 CT and 16 MRI studies were evaluated. CT scans and MR images of 9 patients, which had been obtained in less than two weeks, could be compared to each other. MRI was superior to CT: 6 lesions with a diameter of 1 cm and below were not detected on CT scans, in 5 patients the extent of lesions was underestimated. Cortical involvement, mass effect or signs of atrophy were missing. Only 1 of 67 lesions showed a tiny enhancement after Gd injection. Due to the pattern and spread of lesions, which showed a close correlation to the neurologic symptoms, three different types of PML are suggested: 1. initial precentral demyelinisation with contralateral hemiparesis (n = 8); 2. lesions in temporo-occipital locations with visual disturbances (n = 2); 3. predominantly bilateral lesions of cerebellar white matter with ataxia (n = 4).

Adult↗
PubMed1994

[Experience with surgical treatment of ruptures of the symphysis pubis].

Ten patients with symphyseal rupture and dehiscence of more than 10 mm who underwent different surgical procedures were reexamined between 8 and 59 months after surgery. In case of treatment within 3 weeks after the accident (n = 7) banding with completely absorbable Polydioxanon (PDS) cord (n = 4), PDS cord and crossing K-wires (n = 1), PDS-banding and plate-fixation for concomitant pubic fractures (n = 1), and wire banding (n = 1) were performed. In case of delayed operation (9 till 12 weeks after the injury n = 3) autologous bone grafts from the iliac crest were placed into the symphyseal split after removal of fibrous tissue, and double plate fixation (n = 2) respectively plate fixation and wirebanding (n = 1) were performed. There were no intraoperative and only 2 minor postoperative complications. The follow up revealed good and satisfactory results in 9 patients, and failure in one case. These results are better than to be expected from conservative management of this kind of injury. Banding with cord is a noteworthy alternative to wire banding and plate fixation.

Adult↗
PubMed1994

[Tuberculous meningoencephalitis with primary destruction of the cranial base and secondary development of multiple tuberculomas].

A 34-year-old Vietnamese patient presented with tuberculous meningoencephalitis complicated by hydrocephalus, diabetes insipidus, and radiological evidence of skull base erosion. Despite antituberculous treatment and corticosteroids multiple basal tuberculomas developed. Because of unusual CT and MRI findings casting some doubt on the diagnosis, brain biopsy was performed. The histological finding of an intracerebral tuberculoma supported the initial diagnosis. Some aspects of differential diagnosis and therapy are discussed, with reference to this case.

Adult↗