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S H Duda

Publications and source records attributed to S H Duda.

At least 73 records · Page 4Linked to original sources
PubMed1998

Molecular imaging of atherosclerosis using a technetium-99m-labeled endothelin derivative.

UNLABELLED: Endothelins have been implicated in the pathogenesis of atherosclerosis and restenosis. The aim of this study was to characterize the potential of an endothelin derivative labeled with 99mTc for imaging experimental atherosclerosis in vivo. METHODS: Atherosclerosis was induced by balloon denudation of the infrarenal aorta in eight New Zealand white rabbits followed by a 6-wk period of a standard or 0.5% cholesterol diet in four animals, respectively. Another four rabbits served as controls, without balloon denudation and cholesterol feeding. Digital subtraction angiograms and planar whole-body scintigrams were obtained after intravenous injection of 74 MBq of the 99mTc-labeled endothelin derivative. The aorta was dissected for autoradiography, sudan-III staining, morphometry and immunohistology (anti-alpha-actin, RAM 11) 5 hr after injection. RESULTS: The lesions induced in the infrarenal aorta could be detected in vivo (whole-body scintigrams) in all treated animals only 15 min after injection of 99mTc-endothelin derivative. Autoradiography of the excised aorta revealed good correlation of tracer accumulation and sudan-III-stained lesions. The ratio of accumulation between the induced lesions and untreated vessel wall was 6.8 +/- 1.4 in the cholesterol-fed animals and 6.3 +/- 1.8 in the animals without cholesterol feeding. Accumulation of the endothelin derivative correlated with the number of smooth muscle cells (r = 0.924) but not with the amount of macrophages, the area or the maximum thickness of the plaques. CONCLUSION: Scintigraphic visualization of experimentally induced atherosclerosis in vivo is feasible using an endothelin derivative labeled with 99mTc.

Angiography, Digital Subtraction↗
PubMed1997

[Treatment of osteoid osteoma with CT-guided drilling and ethanol instillation].

HISTORY AND CLINICAL FINDINGS: For 6 months a 25-year-old man had been suffering from intermittent pain in the left upper leg, alleviated by aspirin. Physical examination was unremarkable: local pain was not elicited. INVESTIGATIONS: Routine radiology and computed tomography confirmed the clinically suspected diagnosis of intracortical osteoid osteoma of the femur. Skeletal scintigraphy showed distinctive local concentration of the contrast material. DIAGNOSTIC PROCEDURE, TREATMENT AND COURSE: The lesion's central area was identified by CT and under general anaesthesia drilled into (5 mm diameter drill bit). As the lesion's edges remained partially intact, the cavity was sterilized with 1-2 ml of 96% ethanol. The patient was mobilized after six hours. He has remained free of pain in the subsequent 7 months. CONCLUSIONS: Minimally invasive, CT-guided percutaneous treatment of an osteoid osteoma can be achieved by a combined radiological and percutaneous orthopaedic procedure as an alternative to open surgery.

Adult↗
PubMed1997

[The adjuvant use of the monoclonal antibody c7E3 Fab in peripheral arterial thrombolysis].

Thrombolysis of arterial occlusions has limitations, e.g. it requires extensive time for thrombolysis, occlusions may be resistant to lysis, and the rate of reocclusions may be high. c7E3 Fab inhibits platelet aggregation by binding to the GPIIb/IIIa receptor on platelets. Experimentally, this monoclonal antibody has been shown to decrease, the time required for lysis, and to prevent reocclusion. This is the first report on the adjunctive use of c7E3 Fab in peripheral arterial occlusions in humans. Three patients with occlusion of the iliac or femoropopliteal artery were treated with c7E3 Fab (bolus injection of 0.25 mg/kg KG + i.v.-application 12 micrograms/min for 12 h). In addition, the patients received urokinase (100,000 IU bolus + 100,000 IU/h). Heparin (5,000 IU bolus + 1,000 IU/h) and acetylsalicylate (100 mg/day/p.o.). Occlusion length ranged between 6-40 cm. Therapy was successful in all patients. During the follow-up period (4-6 months) no reocclusion occurred. There were no serious side effects like major bleeding or thrombocytopenia. We conclude that the applied doses appear safe. Even the time required for thrombolysis was short, a conclusion in respect of a significant reduction of the time required for lysis can be drawn only after further controlled studies.

Abciximab↗
PubMed1997

[Value of dacryocystography in localization diagnosis of lacrimal duct stenosis].

PURPOSE: Evaluation of dacryocystography in the preoperative localisation of stenosis of the lacrimal passage. METHOD: The lacrimal system of 20 patients (25 eyes) suffering from lacrimal passage obstruction was examined either by conventional (n = 20) or by digital (n = 5) technique. Diagnostic imaging was evaluated concerning topographic Information of the pathologic lacrimal system, localisation of the level and differential diagnosis of the cause of the obstruction. RESULTS: Cause of the obstruction was chronic dacryocystitis (n = 16), dacryolithiasis (n = 1), atresia of the lacrimal duct (n = 2), posttraumatic lesions (n = 3), rhinosinusitis (n = 1) and carcinoma of the maxillary sinus (n = 1). In 23 of 25 cases (92%) we found an exact correlation between dacryocystography and the intraoperative findings. The variation of stenosis types as well as different examination techniques are presented and compared with literature findings. CONCLUSION: Dacryocystography is a valuable method in the diagnosis and preoperative planing in lacrimal system obstruction.

Adolescent↗
PubMed1997

[Contrast-enhanced MR cholangiography in percutaneous bile duct drainage].

PURPOSE: To evaluate MR-cholangiography after instillation of contrast media via indwelling biliary tubes. METHODS: In 8 patients with stenoses of the central bile ducts, physiological saline solution and diluted contrast media (Gd-DTPA, 5 mmol/l) were consecutively administered via an indwelling biliary tube. MR cholangiograms were obtained before and after saline injection using a HASTE-sequence and after administration of Gd-DTPA using a T1-weighted gradient echo sequence. RESULTS: Peripheral bile ducts were better visualised in the water-sensitive approach than after Gd-DTPA enhancement. In patients with short-time drainage bile duct definition was poor due to periportal oedema. Visualisation of peripheral bile ducts could be improved by injection of saline solution in these patients. After administration of Gd-DTPA via the biliary tube contrast enhancement of the central bile ducts was achieved in all patients except for one patient on long-term drainage with an indwelling Yamakawa tube. CONCLUSION: T1-weighted visualisation of the central bile ducts can be achieved by means of injection of Gd-DTPA via indwelling biliary tubes.

Adult↗
PubMed1997

Phase-contrast MR angiography for detection of arteriosclerotic renal artery stenosis.

PURPOSE: To compare the accuracy of 3-D phase-contrast (PC) MR imaging with a 2-D time-of-flight (TOF) technique in the detection of arteriosclerotic renal artery stenosis. MATERIAL AND METHODS: Twenty-two patients with 28 angiographically proven renal artery stenoses were examined in a prospective blinded fashion by using 2-D TOF MR angiography (MRA) with venous saturation (FLASH) and 3-D PC MRA. The renal arteries were subdivided into 3 segments and graded for the presence of stenoses on a scale of 0-4 by 3 radiologists in blind. RESULTS: The accuracy of TOF and PC imaging in detecting renal artery stenoses was 65% and 77% respectively. Both 2-D TOF and 3-D PC MRA depicted 84% of the stenoses of the proximal renal artery greater than 50% in diameter. Renal artery stenoses greater than 50% and more than 15 mm in distance from the aorta were detected in 40% of cases with the 2-D TOF sequence and in 76% with the 3-D PC technique (p < 0.05). The rate of false-negative results was 32%. CONCLUSION: PC MRA is better at visualizing stenoses in the middle segment of the renal arteries and supplements conventional TOF techniques with additional information. However, even when the two techniques are combined, the false-negative rate in the MR imaging of stenoses of the renal arteries still needs to be reduced.

Aged↗
PubMed1997

[Contrast media-associated nephropathy--pathogenesis and prevention].

Contrast media-associated nephrotoxicity continues to be a relevant cause of acute renal failure, especially in patients with pre-existing renal insufficiency. Alterations in renal hemodynamics and direct tubular toxicity by contrast media are the primary factors believed to be responsible for contrast media-associated nephrotoxicity. We review recent insights into the pathogenesis of this complication and summarize prophylactic strategies focussing on hydration, vasoactive pharmacological agents, and prophylactic hemodialysis'.

Acute Kidney Injury↗
PubMed1996

Treatment of bile duct stones: value of laser lithotripsy delivered via percutaneous endoscopy.

Extraction of stones from the bile ducts via standard endoscopic techniques, a percutaneous transhepatic approach, or a T-tube track can be unsuccessful. We report our preliminary experience with a combination of percutaneous cholangioscopy and dye laser lithotripsy. Flash lamp-excited dye laser (504 nm) lithotripsy delivered by percutaneous cholangioscopy (12 F) was evaluated in 13 patients with stones in the bile ducts. Conventional endoscopic treatment had not been attempted in 4 patients after hepaticojejunostomy and had failed in 3 patients after gastric bypass surgery or gastrectomy, and in 6 patients because of technical difficulties, i.e. due mainly to largeness of stones. In 12 patients a percutaneous transhepatic route was used. In 1 patient the T-tube track was used as access to the bile ducts. Laser lithotripsy resulted in successful fragmentation of stones in 12 patients (92%). The bile ducts cleared spontaneously in 2 patients only. Using additional techniques, i.e. sphincterotomy and stent insertion, the overall combined success rate for duct clearance after laser fragmentation was 100%. Four patients had a retrograde endoscopic sphincterotomy after failed attempts for stone removal at endoscopic retrograde cholangioscopy. Two patients had an antegrade fluoroscopically monitored sphincterotomy. Bleeding complications occurred in 2 patients. This accounted for a high rate (15%) of severe complications. The intrahepatic bleeding in 1 patient was due to an intrahepatic vessel injury by the 13-F sheath. The periampullary bleeding in the other patient occurred after an antegrade papillotomy. Pulsed dye laser lithotripsy proved to be an effective technique in patients with difficult bile duct stones. The main problem of a per cutaneous approach is the complete removal of the fragmented stones, which requires additional procedures in most cases. The percutaneous access is time-consuming and bears a relatively high risk of major bleeding complications. It should therefore be restricted to cases in which conventional endoscopic procedures are impossible or unsuccessful.

Adult↗
PubMed1996

Covered stents for prevention of restenosis. Experimental and clinical results with different stent designs.

RATIONALE AND OBJECTIVES: Metallic stents in small vessels go along with a significant risk of restenosis and reocclusion. Different models of stents and covering materials have been purported to prevent intraluminal neointimal proliferation by cover-based closure of the spaces in the wire mesh. METHODS: Tantalum stents covered with polyethylacrylate/polymethylmethacrylate (PEM) were implanted in the infrarenal aorta of six New Zealand white rabbits by aortotomy and compared with eight rabbits treated with uncovered tantalum stents. For deployment, covered and uncovered stents necessitated a 7-French (F) and 5-F sheath, respectively. In addition, nine human patients with arteriosclerotic lesions of the superficial femoral arteries (stenosis > 5 cm or total occlusion) were treated percutaneously with a Dacron-covered nitinol vascular stent via a 9-F sheath. Patients were followed for a mean of 13.5 months, and control angiography was performed after 6 months. RESULTS: Experimental placement of the tantalum Wiktor stent was feasible technically in all cases. Five of six stents covered with PEM were occluded 3 days after placement despite the intravenous use of heparin and aspirin. In the group with uncovered stents, no area of stenosis greater than 10% was observed. There was a neointimal layer of 89 +/- 68 microns around the stent wires. Stent placement was successful in all patients. In four patients, a hyperergic reaction occurred, resulting in noninfectious periarteriitis. This complication was treated successfully with nonsteroidal antiinflammatory drugs. The primary patency was 50%, and the secondary patency (after application of a second covered stent in two patients) was 63%. CONCLUSIONS: The uncovered stent induces little neointimal proliferation around the stent wires. The insertion of stents covered with PEM into the rabbit aorta was accompanied by a strong thrombotic reaction, despite sufficient anticoagulation. Dacron-covered nitinol stents showed a surprisingly high restenosis rate after 9 months of follow-up. Further research concerning the in vivo properties of new covering materials is mandatory before routine vascular clinical application.

Aged↗
PubMed1996

Ablation characteristics of arterial vessel walls irradiated with the pulsed dye laser--an analysis of variance.

BACKGROUND AND OBJECTIVE: Since most clinical laser angioplasties require the use of over-the-wire delivery systems, we studied the effects of pulsed dye laser energy (504 nm, 1.4 microseconds on arterial vessel walls in combination with a multifiber catheter system. MATERIAL AND METHODS: Postmortem arterial segments (n = 368) were exposed under blood or saline. Laser pulses (n = 100-800) were transmitted via 9F-multifiber-catheters, at energy densities of 3-16 J/cm2. Ablation characteristics revealed by histologic examination and morphometry were analyzed by multiple analysis of variance. RESULTS: Ablation occurred more frequently in saline compared to blood. Below an energy density of 10 J/cm2 ablation occurred in saline only. Specimens irradiated under blood showed only thermal changes at 10 J/cm2. In saline, 92% of normal, 88% of fibro-fatty and 60% of calcified tissue showed ablation at 13 J/cm2. The average ablation threshold in saline was about 3-4 J/cm2 per pulse for normal tissue, 5 J/cm2 for fatty plaques, and 8-9 J/cm2 for calcified plaques. In blood, the average ablation thresholds did not differ significantly between the different stages of arteriosclerosis (12 J/cm2 for normal tissue, 11 J/cm2 for fatty plaque, and 10 J/cm2 for calcified tissue). Carbonization and vacuolization were seen regularly at energy levels > or = 13.4 J/cm2. CONCLUSIONS: Selective ablation of arteriosclerotic tissue with the pulsed dye laser could not be found. Further investigation is needed before an effective ablation of arteriosclerotic arterial tissue can be expected.

Arteries↗
PubMed1995

[Echo contrast agents for the color Doppler sonographic diagnosis of deep femoral venous thrombosis].

PURPOSE: Evaluation of an echo contrast medium (Echovist) for color-coded duplex sonography of deep venous thrombosis of the thigh. MATERIAL AND METHODS: In 19 patients with deep vein thrombosis of the thigh, diagnosed by contrast phlebography, 22 color-coded duplex sonography studies were performed for flow analysis at the top of the thrombus. During the studies 8.5 ml echo contrast medium were injected in an ipsilateral vein at the back of the foot. The flow signals of the non-enhanced color coded duplex sonography were compared with those of the echo enhanced study for differentiation between floating thrombi from those adherent to the vein wall. RESULTS: The echo-enhanced color-coded duplex sonography showed a significant increase in detection of perfusion at the top of the thrombus in comparison with non-enhanced color-coded duplex sonography (p < 0.01). 9 thrombi were regarded as wall adherent after the native study, 7 of these could be identified as floating thrombi by echo-enhanced color-coded duplex sonography. CONCLUSION: Echo-enhanced color-coded duplex sonography yields a significant increase of diagnostic information in certain findings of the non-enhanced color-coded duplex sonography differentiating between floating thrombi and wall adherent thrombi in the deep venous system of the thigh.

Adult↗
PubMed1995

[Spiral CT and CT angiography after coronary bypass surgery].

AIM: Evaluation of spiral-CT and CT-angiography for imaging of venous and arterial coronary bypass grafts during the early postoperative period. PATIENTS AND METHODS: In 198 patients suffering from coronary heart disease, 583 aortocoronary venous grafts (ACVG), 70 arterial grafts and 24 jumped grafts were investigated 9-15 days following coronary surgery. In 57 patients the results were compared to arterial DSA and reconstructive CT-angiography. RESULTS: At arterial DSA 93% of ACVG and 100% of arterial grafts were patent. Spiral-CT demonstrated 104 of 105 ACVG (99%) and 20 of 29 arterial grafts (69%) correct patent. All occluded ACVG (n = 8) were detected. 90% of ACVG but only 32% of arterial grafts were visualised completely over long segments. Imaging of jumped grafts was insufficient. In CT-angiography artificial vessel stenoses impaired correct visualisation of graft morphology. CONCLUSIONS: Spiral-CT allows sufficient differentiation of patent and obstructed ACVG during the early postoperative period. Diagnostic of arterial grafts is of lower accuracy. For CT angiography of venous and arterial coronary grafts further improvements are necessary.

Angiography↗
PubMed1995

[The physician's duty to inform in interventional radiological therapeutic procedures].

PURPOSE: Interventional radiological procedures have important legal implications. The importance of informing the patient ("informed consent") before such procedures is examined in the light of German legal cases. MATERIAL AND METHODS: The German legal literature is reviewed and recent judgments of the Courts are cited. RESULTS: No all-embracing rules can be obtained from the judgments of the German Courts. Mostly one is dealing with individual judgments which can help in a general sense. The patient should be informed well before elective invasive procedures ("informed consent") and the amount of detailed information which is requested to be given to the patient appears to be increasing. Reversal of this trend in the future is unlikely. DISCUSSION: These judgments are of immediate significance for any radiologist who carries out interventional radiological procedures. In the case of complicated techniques the patient should be informed at the time of admission and a definite date for the procedure should be set. Explanations given on the evening before the procedure are deemed to be too late, unless there are exceptional circumstances. Where new forms of therapy are attempted, the information should be even more detailed. In particular it is necessary to stress the experimental nature of the procedure.

Germany↗
PubMed1995

Comparison of magnetic resonance imaging methods for examinations of abdominal aortic aneurysms.

RATIONALE AND OBJECTIVES: Different magnetic resonance imaging techniques were compared with respect to available anatomic information regarding abdominal aortic aneurysms (AAA) and regions involved in thrombosis. METHODS: Twenty patients with AAA were examined by turbo spin-echo (TSE) imaging of coronal and transverse slices, resulting in black blood images. Bright blood imaging was performed using a spoiled gradient-echo sequence with gradient moment nulling. Sets of 25 to 50 thin slices were recorded sequentially in a single slice mode using coronal and transverse orientation. Both sets of bright blood images were reconstructed by maximum intensity projection. RESULTS: In all patients, the size and shape of the AAA could better be assessed by the TSE images than by the gradient-echo images. In contrast, reliable differentiation of thrombotic areas and of the perfused lumen was possible in only 56% of the slices recorded by TSE imaging but in 94% of the gradient-echo images. The two-dimensional inflow technique provided clearly higher sensitivity even to slow blood flow than TSE imaging. Maximum intensity projection reconstructions from sets of coronal two-dimensional inflow images often did not depict the lower part of the AAA because of saturation effects, whereas sets of transverse slices provided complete angiograms of the aortoiliac vascular tree. DISCUSSION: At this time, no single magnetic resonance method can provide all essential information. A comprehensive examination should include TSE imaging for topographic assessment and transverse two-dimensional inflow imaging for analysis of thrombotic areas.

Aged↗
PubMed1995

Normal bone marrow in the sacrum of young adults: differences between the sexes seen on chemical-shift MR imaging.

OBJECTIVE: Age-related changes in the distribution of fatty and nonfatty bone marrow in the pelvis and femur are well recognized. However, mapping not only of age-related MR appearance of normal bone marrow but also of potential variations in females versus males is necessary to differentiate normal findings from marrow disease. Accordingly, we studied possible sex-related differences in the MR imaging appearance of sacral bone marrow in young adults. SUBJECTS AND METHODS: A population of 21 healthy men and 21 healthy women (17-42 years old) was prospectively studied with chemical-shift pulse sequences. MR imaging (1.5 T) of the sacrum was done with frequency-selective fat images (SENEX [selective nonexcitation] 300/27) and water images (SENEX 1000/27) by using an elliptical surface coil. Two independent observers compared the signal intensity of sacral marrow with the signal of fatty tissue planes adjacent to the sacrum (fat images) and the signal of gluteus muscle (water images). T2 relaxation times were estimated by using a two-parametric monoexponential fit on SENEX 1000/27 and SENEX 1000/54 images. RESULTS: In both sexes, fat MR images showed a higher fat content and greater heterogeneity in the bone marrow of the lateral masses than in the vertebral bodies of the sacrum (p < .05). Yellow marrow in the lateral masses of the sacrum appeared brighter in men than in women (p < .05). The heterogeneity of fatty marrow did not differ significantly between the sexes. On water MR images, the signal intensity of the sacrum was higher in women (p < .05). T2 relaxation times were longer in nonfatty marrow with a high water signal intensity (41.8 +/- 5.5 msec versus 33.4 +/- 2.6 msec p < .01). CONCLUSION: Our findings show that the normal appearance of the sacral bone marrow depicted on chemical-shift MR imaging differs between young men and women. Awareness of these differences is important to avoid misinterpretation of normal MR findings seen in patients in this age group.

Adolescent↗
PubMed1994

[Therapeutic bilateral renal artery embolization in the nephrotic syndrome].

Amyloidosis with renal involvement was diagnosed in a 52-year-old man with Crohn's disease for 15 years. A severe nephrotic syndrome developed (proteinuria 40 g daily) with oedema and arterial hypotension (80/60 mm Hg). As adequate substitution treatment was not possible an attempt at medical renal ablation was made with a combination of captopril (25 mg daily), frusemide (80 mg daily) and indomethacin (200 mg daily). The proteinuria decreased to 18 g daily, but serum creatinine concentration rose to 5.8 mg/dl so that chronic haemodialysis had to be undertaken. Yet the patient's clinical state hardly improved and, because of his poor general condition, bilateral nephrectomy was contraindicated. In consequence bilateral catheter embolization of the renal arteries was performed. The urinary protein loss fell at once to 0.5 g daily. Serum protein rose from 3.1 g/dl under substitution to 5.7 g/dl without. During the following six months, while on chronic haemodialysis, the nephrotic syndrome did not recur. However, cardiac involvement in the amyloidosis was demonstrated so that the prognosis is poor. Permanent bilateral embolization of the renal arteries is a feasible method of managing a treatment-resistant nephrotic syndrome in selected patients.

Amyloidosis↗