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Biomedical subjects

K Lackner

Publications and source records attributed to K Lackner.

281 records · Page 16Linked to original sources
PubMed1976

[The manifestations of regional enteritis (Crohn's disease) in the stomach and duodenum (author's transl)].

Involvement of the stomach and duodenum is relatively rare, but produces distrinct radiological changes. In the stomach the antrum and pyloric portion are affected most frequently. Simultaneous involvement of the duodenum is common. Typical radiological changes consist of funnelshaped narrowing of the antrum, decreased motility of the wall of the stomach, cobblestone mucosa with flat ulcers, deformity of the pylorus and first part of the duodenum and stenosing lesions of the duodenum. If the gastro-duodenal changes occur together with the typical appearances in the jejunum, ileum and colon, then the diagnosis can be made by radiology alone.

Adolescent↗
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

The influence of molsidomine on myocardial ischemia and ventricular dynamics. An in-vivo study in anesthetized dogs by means of computer tomography.

In six anesthetized dogs with myocardium partially damaged by ischemia (LAD occlusion), the effect of an i.v. bolus injection of 0.05 mg molsidomine/kg body weight followed by a 6-h i.v. infusion of 0.5 micrograms molsidomine/kg/min on the volume of myocardial ischemia, the relative remaining blood flow in the ischemic area, and the dynamics of the left ventricle were examined by means of computer tomography. The extent of the ischemic volume in the group treated with molsidomine was by far lower than in the control group; this difference was significant if one takes into account the individual heart size. The relative remaining blood flow in the ischemic region was not influenced by molsidomine. The reduction of preload and afterload resulted in corresponding changes in left ventricular areas, segments of these areas, the long axis, thickness of myocardium, ejection fraction and stroke volume. Aortic pressure was lowered insignificantly, heart rate remained nearly unchanged. Plasma analyses of molsidomine. SIN 1 and SIN 1C show that the applied dosage was sufficient to reach a constant concentration over the whole period of observation in the dog.

Animals↗
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

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

Failure of Wallstents in the subclavian vein due to stent damage.

Subclavian vein stenosis and thrombosis are common problems in hemodialysis patients and in the Paget--von Schrötter syndrome. Besides surgery, several less-invasive strategies as balloon angioplasty, drug-induced or mechanical thrombolysis and stenting are used in the treatment of this condition. Three cases of recurrent venous obstruction of the subclavian vein treated with placement Wallstents are described. In all three patients, rethrombosis occurred due to stent failure, two involving stent fragmentation and one, stent collapse.

Adult↗
PubMedDate not supplied

Experimental and clinical evaluation of the PARIS centering catheter for delivery of endovascular gamma-irradiation of femoropopliteal stenoses.

PURPOSE: To investigate the effect of aortic bifurcation and iliac geometry on centered endovascular irradiation (CEI) of femoropopliteal arteries and evaluate procedure-related complications. MATERIALS AND METHODS: In an experimental tubing model, crossover delivery of the dummy wire by an afterloader using different sheaths (Type I: noncrossover; Type II: crossover, length 40 cm; Type III: crossover, length 65 cm) was examined at simulated angles between 20 degrees -100 degrees (aortic bifurcation) and 0 degrees -100 degrees (iliac vessels). In the clinical phase, 28 heparin-anticoagulated patients underwent percutaneous transluminal angioplasty (PTA) for femoropopliteal stenoses followed by CEI (192-iridium, 14 Gray at 2 mm depth of the vessel wall) delivered with the centering catheter (crossover from contralateral leg using a 65-cm-long 8F sheath in 13 patients, noncrossover from ipsilateral leg using a 10-cm 8F sheath in 15 patients). Measurement of the aortic bifurcation angle before advancement of the crossover sheath and rating of iliac artery tortuosity on both sides was retrospectively performed on angiograms. Fifteen controls received no post-PTA CEI. RESULTS: Experimental delivery of the dummy wire was not possible at aortic angles less than 40 degrees with Type I, 60 degrees with Type II, and 30 degrees with Type III sheaths. Advancement of the centering catheter was possible in all patients. CEI failed in two patients with crossover (aortic angle <40 degrees ) and in one obese patient with antegrade approach because advancement of the dummy wire was impossible. Thromboembolism rate was 4.6% during irradiation (2.3% after PTA alone). CONCLUSIONS: CEI in femoropopliteal arteries has a risk of procedure-related thromboembolic complications. Efficacy is affected by vessel geometry.

Angioplasty, Balloon↗
PubMedDate not supplied

Spiral versus conventional CT in routine examinations of the neck.

OBJECTIVE: Our goal was to optimize the efficiency of contrast material (CM) application in routine examinations of the neck by the use of spiral CT and slow power injection. MATERIALS AND METHODS: Dynamic studies were performed in 14 patients to establish a set protocol for spiral CT examinations of the neck. Prospectively, 100 patients were examined either by use of the spiral technique with 100 ml CM (30 g iodine) injected in two phases or in conventional CT with 150 ml CM (45 g iodine). Vascular and parenchymal enhancement was evaluated at three distinct levels of the neck. RESULTS: Despite the reduced CM volume in spiral CT, vascular enhancement was significantly higher at all three levels. Parenchymal enhancement was comparable in both groups. CM exploitation in vascular opacification (ratio of mean enhancement to applied CM volume) was 0.87 in spiral CT compared with 0.43 in conventional CT. CONCLUSION: Spiral CT significantly increases the efficiency of CM application and is well suited for routine examinations of the neck.

Evaluation Studies as Topic↗
PubMedDate not supplied

Prospective comparison of fast SE and GRASE sequences and echo planar imaging with conventional SE sequences in the detection of focal liver lesions at 1.0 T.

PURPOSE: Our goal was to investigate the value of T2-weighted fast SE (FSE) sequences, FSE sequences with shortened echo spacing (UFSE), combined gradient and spin echo sequences (GRASE), and segmented T1-weighted echo planar imaging (EPI) in comparison with conventional SE sequences in the detection of focal liver lesions. METHOD: Thirty-five patients with malignant focal liver lesions underwent MRI at 1.0 T. RESULTS: All fast T2-weighted imaging techniques (FSE, UFSE, GRASE) showed fewer artifacts and overall better image quality than the conventional SE sequence. Quantitative analysis demonstrated that UFSE imaging had the highest tumor/liver contrast/noise ratio (C/N) (13.9 +/- 5.5) followed by FSE (12.7 +/- 4.5), T2 SE (10.9 +/- 4.2), and GRASE (10.0 +/- 4.8) sequences. The differences in C/N between the UFSE and T2 SE sequences was statistically significant (p < 0.05). C/N was significantly higher (p < 0.01) for the T1 SE (-7.4 +/- 3.8) than for the EPI sequence (-0.5 +/- 5.6). CONCLUSION: FSE sequences with shortened echo spacing are valuable for liver imaging at 1.0 T. In comparison with the T2 SE sequence, they yielded better image quality and comparable tumor/liver C/N.

Adult↗