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Biomedical subjects

W Heindel

Publications and source records attributed to W Heindel.

At least 163 records · Page 9Linked to original sources
PubMed1987

[Zenker's diverticulum--diagnosis and therapy].

Clinical, x-ray and endoscopic follow-up of patients operated on for Zenker's diverticulum (pharyngo-oesophageal diverticulum) via myotomy and diverticulectomy permits conclusions in respect of functional results of this therapeutic concept and the preoperative diagnosis that our study has proved to be necessary. Usually the diagnosis can be made on the basis of the characteristic anamnesis. It is confirmed by means of an oesophagogram, if necessary with a gastrointestinal passage. Besides visualisation of Zenkers diverticulum, attention must be paid especially to associated neuromuscular functional disturbances of the oesophagus. Preoperative endoscopy is necessary in individual cases only. In respect of therapy, it appears mandatory to perform a sufficiently extended (3-5 cm) myotomy of the pars transversa musculi cricopharyngei because of the frequently seen disturbance of coordination of the pharyngo-oesophageal sphincter, besides removing the diverticulum.

Diagnosis, Differential↗
PubMed1986

[Magnetic resonance tomography of brain tumors--comparison of the results using the multi-echo technic and gadolinium-DTPA].

In thirty-seven MR examinations of intracranial tumours equivalent sections were obtained in a multi-echo technique before and after intravenous injection of 0.1 mmol. gadolinium DTPA/kg body weight. From this comparison the following preliminary conclusions have been drawn concerning the demonstration of the tumour, its delineation and type: Contrast administration does not unequivocally improve the sensitivity. In 55% of the cases, differentiation between tumour and oedema respectively normal brain tissue was easier after Gd-DTPA. Diffusely infiltrating gliomas remain a problem, since their extent is uncertain with or without contrast medium. The structure of the tumour can already be adequately characterized by the multi-echo technique. In order to diagnose the type of tumour, the criteria which apply to Gd-DTPA are similar to those used for iodine-containing contrast media in CT.

Astrocytoma↗
PubMed1986

[Mediterranean type of primary lymphoma in the small intestine - a diagnostic problem].

In primary lymphoma of the gastro-intestinal tract radiological and clinical findings are often uncharacteristic for a long time and even tissue biopsy may be difficult to classify pathohistologically. The conclusive diagnosis of this rare entity can be established radiologically only in combination with serological, endoscopic und pathologic findings during the course of the disease.

Adult↗
PubMed1985

[Indications for nuclear magnetic resonance tomography in tumors of the facial skeleton and neck area].

The diagnostic value of magnetic resonance tomography is examined in relation to computed tomography on the basis of 32 patients subjected to magnetic resonance tomography who had pathological processes in the craniofacial, parapharyngeal and neck regions. The high power of contrast resolution, multiplanar imaging, and good circumscription of cervical vessels, offer advantages over computed tomography in respect of space-occupying growths in the median and lower parts of the craniofacial skull. A disadvantage is the poorer detectability of tumour-conditioned bone destruction at the base of the skull and at the facial bones; in such cases, computed tomography remains the method of choice.

Adult↗
PubMed1983

Nuclear magnetic resonance (NMR) tomography of the central nervous system: comparison of two imaging sequences.

A brief description of a nuclear magnetic resonance (NMR) imaging system and preliminary results from its clinical evaluation in the study of various central nervous system diseases are presented. Particular attention is paid to NMR capabilities for soft tissue discrimination, topographical demarcation, and specificity of diagnosis. Two imaging sequences were used: (a) Spin echo measurements with four sets of imaging parameters revealed the different appearances of normal and pathological structures. (b) Inversion recovery images showed marked gray-white matter contrast and clear depiction of pathological lesions. Finally, a number of measurements of longitudinal (T1) and transverse (T2) relaxation times of normal and pathological tissues were carried out.

Adult↗
PubMedDate not supplied

Phase-contrast pulsatility measurements: preliminary results in normal and arteriosclerotic iliofemoral arteries. Work in progress.

Magnetic resonance (MR) flow measurements were obtained in six healthy volunteers and 30 patients with arteriosclerotic disease with a 1.5-T imager and a pulse sequence for flow quantification based on flow-induced phase shifts. The iliac arteries were investigated in eight and the femoral arteries in 28 subjects. A trigger pulse, followed by the acquisition of 30 evenly distributed data sets, was applied every second heartbeat, thus eliminating any acquisition gap in a full heart cycle. For quantitative analysis, flow velocity was plotted as a function of time. Systolic acceleration, postsystolic deceleration, and pulsatility of flow were calculated and compared with stenosis grades determined from recent intraarterial digital subtraction angiograms. The flattening of the temporal flow patterns correlated with local severity of vascular occlusive disease.

Adult↗
PubMedDate not supplied

Quantitative measurements with localized 1H MR spectroscopy in children with Canavan's disease.

Canavan's disease is an autosomal recessive hereditary leukodystrophy resulting from deficiency of the enzyme aspartoacylase. Two children suffering from this metabolic brain disease were examined using image-guided localized proton spectroscopy. The absolute concentrations of metabolites were determined. These data demonstrate, for the first time, that the well known increase of the N-acetylaspartic acid (NAA)/Cho ratio in this disease may be not only due to a reduction of choline-containing compounds in brain tissue but, at least in specific cases, also due to an increase of the NAA concentration, which is a result of the enzyme defect.

Aspartic Acid↗
PubMedDate not supplied

Localized 31P MR spectroscopy of the transplanted human kidney in situ shows altered metabolism in rejection and acute tubular necrosis.

The purpose of this study was to investigate the function of transplant kidneys in situ, and to detect pathologic changes, using volume-selective phosphorous NMR spectroscopy (31P MRS). Localized 31P MR spectra were obtained from 37 patients using a whole-body MR scanner with a combination of surface coils, adiabatic excitation pulses, and a modified image-selected in vivo spectroscopy (ISIS) sequence. Seventeen patients with pathologic changes after renal transplant were compared with a control group of 20 patients with no evidence of transplant dysfunction. The transplant kidneys with rejection reaction showed higher ratios of inorganic phosphate (P2i) to adenosine triphosphate-alpha (ATP-alpha) than the normal control group (.4 +/- .16 compared with .22 +/- .11, P = .01) and reduced pH. The spectra of transplant kidneys with tubular necrosis had lower phosphomonoester (PME)/phosphodiester (PDE) ratios than the control group (.65 +/- .35 compared with .96 +/- .5, P = .04). The pathologies of rejection and tubular necrosis could be differentiated from each other by pH (6.93 +/- .1 in rejection versus 7.14 +/- .19 in tubular necrosis, P = .04). Preliminary results indicate that localized image-guided 31P MR spectroscopy of transplant kidneys in situ can detect rejection reactions and acute tubular necrosis noninvasively, providing an incentive for further research.

Adenosine Triphosphate↗
PubMedDate not supplied

Fast and ultrafast magnetic resonance imaging in renal lesions.

Our purpose was to analyze and compare the image quality and contrast-to-noise ratio (CNR) of different fast T1- and T2-weighted sequences with conventional spin-echo sequences in renal MRI. Twenty-three patients with focal renal lesions were examined with a T2-weighted ultrafast turbo spin-echo (UTSE) sequence with and without frequency selective fat suppression (SPIR), a combined gradient-and-spin-echo sequence (GraSE), and a conventional spin-echo sequence (SE). In addition, T1-weighted images were obtained pre- and postcontrast, using a fast spin-echo sequence (TSE) with and without SPIR and the conventional SE sequence. Among the T2-weighted images, the highest CNR and the best image quality were obtained with the UTSE sequence, followed by the fat-suppressed UTSE sequence. GraSE and conventional SE sequences showed a significantly lower CNR and image quality (p < 0.05). The T1-weighted sequences did not show significant differences, in either precontrast or postcontrast measurements. T2-weighted UTSE with and without fat suppression combined excellent image quality and high CNR for imaging and detection of renal lesions. The T1-weighted fast sequences provided no alternative to the gradient-echo or to the conventional SE sequences. The results of this systematic study suggest the use of T2-weighted fast techniques for improved diagnostic accuracy of renal MRI.

Adenoma, Oxyphilic↗
PubMedDate not supplied

Treatment of a ruptured anastomotic esophageal stricture following bougienage with a Dacron-covered nitinol stent.

A patient suffering from esophagorespiratory fistula after bougienage of a benign stricture at the site of the anastomosis between a jejunal interposition and the esophagus was referred for interventional treatment. A prototype nitinol stent centrally covered with Dacron was implanted under regional anesthesia and fluoroscopic guidance. The self-expanding prosthesis dilated the stenosis completely and closed the fistula, with consequent improvement in respiratory and nutritional status and thus the general quality of life. The patient was able to eat and drink normally until death 3 months later due to progression of his underlying malignant disease.

Anastomosis, Surgical↗
PubMedDate not supplied

MR and optical approaches to molecular imaging.

With an increasing understanding of the molecular basis of disease, various new imaging targets have recently been defined that potentially allow for an early, sensitive, and specific diagnosis of disease or monitoring of treatment response. Different approaches to depict these molecular structures in vivo are currently being explored by the molecular imaging community. We briefly review methodologies for molecular imaging by magnetic resonance imaging and optical methods. Special emphasis is put on different contrast agent designs (e.g., targeted and smart probes). New technical developments in optical imaging are briefly discussed. In addition, current research results are put into a clinical perspective to elucidate the potential merits one might expect from this new research field.

Capillary Permeability↗
PubMedDate not supplied

CT-guided lumbar sympathectomy: results and analysis of factors influencing the outcome.

PURPOSE: To prospectively analyze the effectiveness of computed tomography-guided percutaneous lumbar sympathectomy (CTLS) in patients with peripheral arterial occlusive disease in relation to angiographic findings and vascular risk factors. METHODS: Eighty-three patients were treated by CTLS. After clinical evaluation of the risk profile and diagnostic intraarterial digital subtraction arteriography, 14 patients underwent unilateral, and 69 bilateral one-level treatment. Follow-up studies took place on the day following the intervention, after 3 weeks, and after 3 months. RESULTS: A total of 152 interventions were performed in 83 patients. After 3 months, clinical examination of 54 patients (5 patients had died, 24 were lost to follow-up) revealed improvement in 46% (25/54), no change in 39% (21/54), and worsening (amputation) in 15% (8/54). There was no significant statistical correlation among any of the analyzed factors (diabetes mellitus, arterial hypertension, smoking, hyperlipidemia, obesity, hyperuricemia, number of risk factors, ankle-arm index, and angiography score) and the outcome after CTLS. Three major complications occurred: one diabetic patient developed a retroperitoneal abscess 2 weeks after CTLS, and in two other patients ureteral strictures were detected 3 months and 2 years after CTLS, respectively. CONCLUSION: As no predictive criteria for clinical improvement in an individual patient could be identified, CTLS, as a safe procedure, should be employed on a large scale in patients who are unsuitable for treatment by angioplasty or revascularization.

Adult↗
PubMedDate not supplied

Artifacts in MR imaging after surgical intervention.

Artifacts are encountered repeatedly in magnetic resonance (MR) imaging after neurological orthopedic surgery, although there is no evidence of metallic foreign bodies on radiography and CT. Experiments demonstrated that surgical filling materials, such as bone cement and bone transplants are not the cause of the artifacts. On the other hand, we have been able to show that short-term contact between a diamond drill and untempered operating instruments can cause abrasions and set free minute metallic fragments. Those particles are missed by X-ray procedures including CT but cause MR artifacts by local disturbance of the homogeneity of the magnetic field. Therefore, MR represents a highly sensitive method to trace extremely small amounts of magnetic substances. Postsurgical MR, however, may be of limited value because of the disturbing artifacts.

Animals↗
PubMedDate not supplied

Combined 1H-MR imaging and localized 31P-spectroscopy of intracranial tumors in 43 patients.

Combined imaging and volume-selective spectroscopy of normal human brain tissue and tumors located anywhere in the brain could be obtained routinely in a clinical setting. Image-guided localized phosphorus MR spectra of healthy brain tissue have been reproducible, but further examinations seem necessary to determine individual physiologic variations. Compared with healthy brain tissue, spectra from meningiomas demonstrated the most obvious differences: the phosphocreatine peak decreased below the level of adenosine triphosphate, and the phosphodiester signal was reduced, whereas the phosphomonoester peak increased in some cases. Malignant gliomas showed less distinct changes: in particular, the phosphodiester peak was reduced and, in several cases, seemed to split. Often the phosphocreatine signal was diminished. In tumors with cystic components a poor signal-to-noise ratio was found. Four nonmalignant astrocytomas could not be differentiated from normal brain tissue spectroscopically. It has to be proved by an increased number of cases and quantification whether the observed spectral patterns can be correlated to histology. In three patients, follow-up studies during and after radiotherapy were performed. Metabolic changes were observed in one patient in a time frame in which imaging methods did not detect any change. Phosphorous spectroscopy has the potential to emerge as a useful tool in this field.

Adult↗
PubMedDate not supplied

MR sialography: initial experience using a T2-weighted fast SE sequence.

PURPOSE: The aim of this study was to evaluate an MR technique optimized for imaging of the parotid gland ductal system. METHOD: The pulse sequence was optimized in 10 volunteers to depict static or nearly static fluid in the parotid ductal system. A heavily T2-weighted fast SE sequence (TR 3,600 ms/TE 800 ms) with a slice thickness of 30-40 mm using an 8 cm surface coil allowed depiction of the fluid-filled parotid duct. Thirteen patients with benign as well as malignant parotid gland pathologies were examined: sialadenitis (n = 2), sialadenosis (n = 3), Heerfordt syndrome (n = 1), pleomorphic adenoma (n = 2), parotid carcinoma (n = 1), lymphoepithelial carcinoma (n = 1), cystadenolymphoma (n = 2), and non-Hodgkin lymphoma (n = 1). RESULTS: The heavily T2-weighted projection image yielded good quality sialographic images. The main duct and primary branching ducts were clearly depicted in all normal cases. The main duct was visualized in all patients. Intra- and extraglandular duct widening and ductal strictures were well depicted. Sialolithiasis with a calculus in the main duct was correctly demonstrated in one case. CONCLUSION: MR sialography is noninvasive and does not depend on duct cannulation or contrast agent injection. Initial experience with a thick slice projection technique indicates that MR sialography can be successfully applied to image the parotid gland ductal system.

Adenolymphoma↗
PubMedDate not supplied

Abdominal lymphoma staging: is MR imaging with T2-weighted turbo-spin-echo sequence a diagnostic alternative to contrast-enhanced spiral CT?

PURPOSE: To evaluate the diagnostic value of MR imaging in abdominal lymphoma staging, in comparison with that of the established spiral CT, within the context of a prospective study. METHODS: 50 patients with non-Hodgkin (n = 27) and Hodgkin lymphoma (n = 23) were examined with a plain T2-weighted TSE sequence (parameters: TE 90 ms, TR >2.500 ms, slice thickness 8 mm, slice interval 0.8 mm, ETL 20, NEX 4), and with spiral CT following oral and intravenous administration of contrast agent. RESULTS: Both CT and MR imaging agreed in showing abdominal lymphomas in 34/50 cases. The size of the detected lymphomas was between 1.5-9 cm (mean: 4.3 +/-2.2 cm). In the analysis of the individual lymph node sites, CT showed involvement of the paraaortic lymph nodes in 29/50 patients, compared with 28/50 in MRI, and involvement of the portal lymph nodes in 15/50, compared with 12/50. Both techniques showed the iliac lymph nodes in 21/50 patients, the inguinal lymph nodes in 10/50, and the mesenteric lymph nodes in 11/50. Both techniques also showed focal organ lesions in 12/50 cases. CONCLUSIONS: In the staging of abdominal lymphomas, MR imaging with a T2-weighted TSE sequence can be regarded as equal to spiral CT in the detection of lymph adenopathy and the demonstration of focal organ lesions. In addition to the absence of ionizing radiation, the advantage of MR imaging is that there is no necessity for oral or intravenous administration of contrast agent.

Abdominal Neoplasms↗