Primary percutaneous aspiration and thrombolysis for the treatment of acute embolic superior mesenteric artery occlusion.

OBJECTIVES: To evaluate technical success rate and clinical outcome of patients with acute embolic superior mesenteric artery (SMA) occlusion who were treated with primary percutaneous revascularization. METHODS: At three medical centers the radiological information system databases were used to identify all patients in whom primary percutaneous revascularization for the treatment of acute embolic SMA occlusion was attempted between 2001 and 2010. Percutaneous treatment was performed in 15 patients (median age 80 years, range 49-88 years). These patients represent the study population. Eleven patients reported abdominal pain. Five patients exhibited peritoneal signs. Revascularization was defined as complete technical success if (1) patency of the SMA with residual stenosis of not more than 30% in diameter and (2) sufficient perfusion of the entire bowel were obtained. RESULTS: Complete technical success was achieved in eleven patients. After percutaneous revascularization laparotomy was performed in six patients and in three of them bowel resection was carried out (length of resected segments 20-80 cm). The 30-day mortality was 33% (five of 15 patients). None of the surviving patients exhibited short-bowel syndrome. CONCLUSIONS: Primary percutaneous aspiration and thrombolysis constitutes a promising alternative to surgical revascularization in selected patients with acute embolic SMA occlusion.

[Radiological placement of peripheral central venous access ports at the forearm. Technical results and long term outcome in 391 patients]. / Radiologische Implantation zentralvenöser Portsysteme am Unterarm. Implantationsergebnisse und Langzeit-Follow-up bei 391 Patienten.

PURPOSE: To retrospectively analyze the technical result and long term outcome of central venous arm ports placed by radiologists. MATERIALS AND METHOD: Over a 5-year period, 399 arm ports were implanted by radiologists in 391 patients. The system consists of a low profile titanium chamber and a silicone catheter. Ports were placed at the forearm after puncture of a vein proximally to the elbow under fluoroscopic guidance. In a retrospective analysis the technical results and the long term outcome were evaluated. Complications were documented according to the standards of the society of interventional radiology. RESULTS: In 391 patients a total of 98 633 catheter days were documented (1 - 1325 days, mean 252 days). Primary technical success was 99.25 % (396 / 399) with a 100 % secondary technical success rate. No severe procedural complications, e. g. pneumothorax or severe hemorrhage, were found. A total of 45 complications occurred (11.28 %, 0.45 / 1000 catheter days), including 8 portal pocket infections (27 - 205 days, mean 115 days). Fifteen ports were explanted because of complications. The complication rate corresponds to the data from subclavian ports and is less than the complication rates published in large surgical trials. CONCLUSION: Implantation of central-venous arm ports by radiologists is safe and minimally invasive. No severe immediate procedural complications occur due to the peripheral implantation site. Long term complication rates are comparable to other studies of radiological or surgical port implantation at different sites.

[Pulmonary embolism caused by PMMA in percutaneous vertebroplasty. Case report and review of the literature]. / Lungenembolie durch PMMA bei perkutaner Vertebroplastie. Fallbericht und Literaturübersicht.

We report on an 80-year-old female patient with osteoporotic collapse of the L1 vertebra who developed absolute stenosis of the spinal canal. During preoperative vertebra augmentation with PMMA (polymethylmethacrylate), pulmonary embolism developed due to perivertebral leakage of acrylic cement. According to the literature, leakage of PMMA during (percutaneous) vertebroplasty is a more frequent complication than assumed so far. In view of the favorable prognosis of osteoporotic vertebral compression fractures with noninvasive management, we emphasize the need for clear and individual indications and adequate technical settings.

Pain in femoral arteriography. A double-blind, randomized, clinical study comparing safety and efficacy of the iso-osmolar iodixanol 270 mgI/ml and the low-osmolar iomeprol 300 mgI/ml in 9 European centers.

PURPOSE: To compare the injection-associated pain and heat sensation after administration of the iso-osmolar contrast medium (IOCM) iodixanol (Visipaque trade mark 270 mg I/ml) and the low osmolar contrast medium (LOCM) iomeprol (Iomeron trade mark 300 mg I/ml) in femoral arteriography. MATERIAL AND METHODS: 352 patients received iodixanol or iomeprol in a prospective, double-blind, randomized, parallel-group clinical trial. The first injection during femoral arteriography (DSA with automated stepping) was standardized. Injection-associated pain and heat sensation, efficacy and safety up to 72 h were evaluated. RESULTS: The iodixanol group reported significant less injection-associated pain than the iomeprol group after the first injection (7.4% vs. 17.6%; p = 0.007), and after all injections (11% vs. 19.4%; p = 0.045). Iodixanol caused less heat sensation after the first injection (p = 0.007) and after all injections (p = 0.029). Heat sensations in the iodixanol group were less intense after all injections (p < 0.0001). No difference was found between the groups regarding the frequency of patients having adverse reactions (5.1% vs. 4%). CONCLUSION: The IOCM iodixanol caused significantly less frequent injection-associated pain and heat sensation than the LOCM iomeprol during femoral arteriography.

Selective intraarterial fibrinolysis of acute central retinal artery occlusion.

PURPOSE: To evaluate the outcome of our patients with central retinal artery occlusion after local fibrinolysis and to compare these data with results reported in the literature. MATERIAL AND METHODS: Over a period of 7 years, 22 patients (11 male, 11 female, mean age 64.6 +/- 12.1 years) were treated with super-selective local fibrinolysis. In 1 case, treatment was carried out via the maxillary-ophthalmic anastomoses due to preexisting occlusion of the ipsilateral internal carotid artery. The latency period from the onset of symptoms to the beginning of therapy was 7.6 +/- 1.8 h. Urokinase was used in 7 cases (300,000-1.1 million units) and recombinant tissue plasminogen activator (20-40 mg) was applied in 15 patients. Visual acuity and fundus were examined before and after treatment. RESULTS: One patient (1/22 = 4.6%) recovered completely and regained a visual acuity of 20/20. Six patients (6/22 = 27.3%) showed a marked improvement with a range of visual outcome from 20/800 to 20/320. In 2 cases (2/22 = 9.1%) only a slight improvement was observed, with a visual outcome allowing detection of hand movements. In 13 cases (13/22 = 59.1%) no change in visual acuity as a result of treatment was observed. In 2/22 cases (9.2%) reversible neurological side-effects occurred, in 1 case suffered a stroke, and in another case intracerebral bleeding was observed. CONCLUSION: In our study, the recovery of visual acuity and the complication rate were not as positive as reported in the literature.

[Evaluation of a hemostatic device with percutaneous collagen application (VasoSeal) compared to a mechanical compression system (Compressar) after transfemoral catheterization of patients suffering from arterial occlusive disease]. / Evaluation eines Verschlusssystems mit perkutaner Kollageneinbringung (VasoSeal) im Vergleich zu einem mechanischen Kompressionssystem (Compressar) nach Femoralispunktion bei Patienten mit AVK.

PURPOSE: Comparison of the efficacy of VasoSeal and a mechanical compression system (Compressar) for percutaneous hemostasis after femoral arterial catheterization of patients with arterial occlusive disease. MATERIALS AND METHODS: 60 patients underwent either diagnostic angiography or interventional procedures. The level of anticoagulation, blood pressure, and activation clotting time were recorded, and the time to hemostasis after sheath removal was measured. VasoSeal application was considered "successful" if the compression time was less than two minutes. On the subsequent day as well as 4 months later, color coded Doppler ultrasound was performed to register treatment success and potential (late) complications. RESULTS: 57 patients qualified for inclusion in this study. In 21 of the 26 patients who underwent the procedure with the VasoSeal, immediate hemostasis was achieved within 1.75 minutes. In all 31 patients who had the Compressar applied, hemostasis was successful with a mean compression time of 17.4 minutes. Thus, VasoSeal significantly reduced hemostasis time irrespective of anticoagulation status, but it had a much higher incidence of minor local complications (bleeding, hematoma) compared to the control group (34.6 % vs. 5.8 %). The technical success was lower with VasoSeal than with Compressar (81 % vs. 100 %). Both groups had no severe or late complications. CONCLUSION: According to our results, VasoSeal does not provide a suitable alternative compared to the effective, safe and cheap application of Compressar as a hemostatic device.

Appearance of vascular stents in computed tomographic angiography: in vitro examination of 14 different stent types.

RATIONALE AND OBJECTIVES: To evaluate the appearance of the vessel lumen after implantation of different vascular stents with the use of a computed tomographic (CT) angiography model. METHODS: A vascular phantom was studied with helical CT and different slice thicknesses (2 and 3 mm) and pitch values (1.0, 1.5, and 2.0). Original transverse CT images and coronal reformations were evaluated. Fourteen different stents were analyzed with regard to changes in the stent lumen (attenuation values, noise, and artificial lumen narrowing). RESULTS: Some stents caused artifacts resulting in potential errors during evaluation of their patency. Assessment of the lumen was impaired in two stents (Strecker tantalum and Passager). Increased attenuation values were measured in all stents (increase of 8%-145%). The degree of artificial lumen narrowing was 4.4% to 77.8%. CONCLUSIONS: In most stents, reliable evaluation of the stent lumen seems possible. However, knowledge of the artifacts caused by different stent types is useful for the assessment of stent patency with CT angiography.

[The endoleak problem in endoluminal therapy]. / Das Problem der Endoleckage bei endoluminaler Therapie.

Endovascular treatment of aortic aneurysms with stent grafts was performed increasingly in recent years. The most frequent complication after endovascular therapy of aortic aneurysms is an endoleak. In case of a persistent endoleak, diameter of the aneurysm is increasing with a high risk of aneurysm ruptur. Diagnostic tools are spiral computed tomography and angiography. Spiral computed tomography is the most sensitive method for the diagnosis of an endoleak ad should be performed with a biphasic acquisition. In- and outflow of sidebranches can be identified correctly with selective angiography in 86%. Perigraft endoleaks should be treated in any case. Patent side branches generally are observed over a period of 6 months. After 6 months approximately half of these endoleaks are thrombosed. Is there an increasing of the diameter of the aneurysm or any changing in the morphology of the aneurysm there is an indication for embolisation of these sidebranches of the aneurysmal sac. Preinterventional embolisation of patent sidebranches is under discussion. Type I endoleaks can be managed by additional stent-graft implantation or coil embolisation. In case of type II endoleaks in- ad outflow vessels should be embolised with coils. Therapy of type III endoleak is performed mostly by additional stent-graft placement. The total incidence of secondary interventions in the Eurostar-study was nearly 10% per year.

[The problem with endoleakage in endoluminal therapy]. / Das Problem der Endoleckage bei endoluminaler Therapie.

Endovascular treatment of aortic aneurysms with stent grafts was performed increasingly in recent years. The most frequent complication after endovascular therapy of aortic aneurysms is an endoleak. In case of a persistent endoleak, diameter of the aneurysm is increasing with a high risk of aneurysm rupture. Diagnostic tools are spiral computed tomography and angiography. Spiral computed tomography is the most sensitive method for the diagnosis of an endoleak ad should be performed with a biphasic acquisition. In- and outflow of sidebranches can be identified correctly with selective angiography in 86%. Perigraft endoleaks should be treated in any case. Patent side branches generally are observed over a period of 6 months. After 6 months approximately half of these endoleaks are thrombosed. Is there an increasing of the diameter of the aneurysm or any changing in the morphology of the aneurysm there is an indication for embolisation of these sidebranches of the aneurysmal sac. Preinterventional embolisation of patent sidebranches is under discussion. Type I endoleaks can be managed by additional stent-graft implantation or coil embolisation. In case of type II endoleaks in- ad outflow vessles should be embolised with coils. Therapy of type III endoleak is performed mostly by additional stent-graft placement. The total incidence of secondary interventions in the Eurostar-study was nearly 10% per year.

[Treatment of para-ostium renal artery stenoses with a new, solidly premounted balloon expandable stent]. / Behandlung von ostiumnahen Nierenarterienstenosen mit einem neuen, fest vormontierten, ballonexpandierbaren Stent.

PURPOSE: Evaluation of the handling, technical success rate, and six-months patency rate of a new, premounted balloon-expandable stent in ostial renal artery stenoses. MATERIAL AND METHODS: In a prospective study, 27 ostial renal artery stenoses in 20 patients were primarily treated with the new "Renal Bridge Stent" (Medtronic AVE, Düsseldorf). All patients had a history of hypertension and 8 patients had renal dysfunction. The handling and visibility of the stent was scored on a three grade scale by the operators. Follow-up angiography including intra-arterial trans-stenotic pressure measurements was performed in 23 out of 27 stenoses (17 patients). RESULTS: Handling and visibility were scored as good by all operators. 26 of 27 stenoses were treated with technical success by implantation of 28 stents. The mean degree of stenosis was reduced from 74.2% to less than 5%. At 6 months, 8 stents out of 23 (35%) showed a significant in-stent stenosis (stenosis degree > 50% and intra-arterial pressure gradient > 10 mmHg). The stenosis rates were 63% using 5-mm stents, 30% using 6-mm stents, and 0% using 7-mm stents. CONCLUSION: Endovascular treatment of ostial renal artery stenosis with the used stent is safe and effective. The new stent shows a good handling and visibility. The high rate of in-stent stenoses might be explained by the rigid follow-up protocol including angiography, trans-stenotic pressure measurements, and the high number of 5-mm vessels in our study.

Renal time-resolved MR angiography: quantitative comparison of gadobenate dimeglumine and gadopentetate dimeglumine with different doses.

PURPOSE: Results with different doses of gadobenate dimeglumine and gadopentetate dimeglumine were compared at magnetic resonance (MR) angiography of the renal arteries. The signal-to-noise ratio (SNR) was evaluated as a quantitative measure of image quality. MATERIALS AND METHODS: Sixty consecutive patients (age range, 24-81 years; mean age, 65 years) underwent intraarterial digital subtraction angiography (DSA) and contrast material-enhanced time-resolved MR angiography. DSA was the standard of reference. Fifteen patients received gadopentetate dimeglumine at doses of 0.2 or 0.1 mmol per kilogram of body weight. Fifteen patients received gadobenate dimeglumine at doses of 0.05 or 0.1 mmol/kg. The SNR was calculated in the aorta and both main renal arteries. The number and degree of stenoses of the renal arteries and accessory vessels were evaluated by four observers. RESULTS: SNRs with gadobenate dimeglumine at a dose of 0.1 mmol/kg were significantly superior to those with gadopentetate dimeglumine at a dose of 0.1 mmol/kg. Differences were not statistically significant between the SNRs in the other groups. Eleven (85%) of 13 hemodynamically significant renal artery stenoses were detected correctly with MR angiography as were 22 (85%) of 26 accessory renal arteries. CONCLUSION: SNRs with gadobenate dimeglumine were higher than those with gadopentetate dimeglumine, but in most cases the differences in SNRs were not statistically significant.

[Percutaneous transfemoral implantation of a new, flexible thoracic aorta endoprosthesis using a percutaneous suture system for vascular suture--initial experiences]. / Perkutane transfemorale Implantation einer neuen, flexiblen thorakalen Aortenendoprothese unter Verwendung eines perkutanen Nahtsystems zum Gefässverschluss--erste Erfahrungen.

PURPOSE: To evaluate the transfemoral placement of a new, flexible stent-graft into the thoracic aorta and the suture-mediated closure of the femoral access. PATIENTS AND METHODS: Five patients were treated endovascularly with a stent-graft for an aneurysm (n = 3) or acute dissection (n = 2) of the thoracic aorta via a femoral 24 F sheath. The femoral access site was closed with two suture-mediated closure devices after placement of the stent-graft. RESULTS: The aneurysm or the false lumen was excluded from perfusion by the placement of the stent-graft in all patients. Hemostasis at the femoral access site was successful in all patients with the percutaneous suture device. A minor stenosis of the femoral artery was found angiographically in four patients after suture-mediated closure. Besides a reversible renal failure due to the medically induced hypotension for the treatment of an acutely ruptured aneurysm, no complications resulted from the stent-graft placement or the percutaneous suture. CONCLUSION: The percutaneous transfemoral placement of stent-grafts in the thoracic aorta using a suture-mediated closure of the access site is technically feasible. Long-term results of the technique have to be awaited.

Spinal metastases from renal cell carcinoma: effect of preoperative particle embolization on intraoperative blood loss.

BACKGROUND AND PURPOSE: Surgical repair of spinal metastases from renal origin is often complicated by excessive bleeding. The purpose of this study was to assess the effect of preoperative particulate embolization on intraoperative blood loss. METHODS: Twenty spinal metastases from renal origin (17 patients) treated by preoperative embolization with polyvinyl alcohol particles were analyzed retrospectively. Surgical decompression was performed within 2 days after embolization. A control group of 10 patients with 11 spinal metastases of renal origin underwent surgery without embolization. The effect of preoperative embolization, of completeness of embolization, and of particle size on the estimated intraoperative blood loss was analyzed using nonparametric statistical tests. RESULTS: Complete embolization was achieved in 10 cases and partial embolization in the other 10. The estimated blood loss of 19 embolized and 11 control cases was available from the surgical report. Median intraoperative blood loss in 19 embolized lesions was 1500 mL (range, 300-8000 mL), compared with 5000 mL (range, 1440-15000 mL) in the control group. Even after partial embolization, blood loss (median, 2000 mL) was significantly lower than in the control group. No significant differences in estimated blood loss were noted between the use of particles smaller than 250 microm and those larger than 250 microm. No embolization-related permanent neurologic deficit or skin or muscle necrosis occurred. CONCLUSION: Preoperative embolization of spinal metastases of renal origin with polyvinyl alcohol particles is safe and might reduce intraoperative blood loss significantly. Even partial embolization seems to be effective.

[Results after placement of Memotherm stents in iliac and femoral arteries]. / Ergebnisse nach Memotherm-Stent-Implantation in Becken- und Leistenarterien.

PURPOSE: To evaluate the effectivity, safety and midterm patency rates of iliac and femoral stent placement with the Memotherm stent (Bard-Angiomed, Karlsruhe). MATERIAL AND METHODS: In 41 patients (11 female, 30 male, mean age 63.9 years) 49 lesions were treated with 50 stents. Mean lesion length was 4.8 cm for 5 occlusions and 3.1 cm for 44 stenoses. Lesions were located in the common iliac (n = 31), the external iliac (n = 15), and the common femoral artery (n = 3). Patients were followed-up clinically, with ankle-brachial indices (ABI), and angiography. Angiographic patency rates (< or = 50% restenosis) were calculated using the Kaplan-Meier method, ABIs were compared before and after therapy with the Wilcoxon test. RESULTS: An immediate technical success was achieved in 48/49 lesions (98%, intention-to-treat). Visibility of the stent was poor. Four stent placement procedures were complicated by an advancement of the stent, which could not be corrected. A thrombosis of one stent during deployment had to be treated surgically. After a mean of 10.4 months (6-24) 33 lesions were followed-up with angiography. The primary angiographic patency rate was determined to be 89.9% after 9 months. An improvement of at least one Fontaine stage was observed in 85.4%. The mean ABI increased significantly from 0.64 to 0.84 after therapy. CONCLUSIONS: The patency rate of the Memotherm stent is comparable to that of other stent systems. The poor visibility and the advancement of the stent during deployment requires further modifications.

MR imaging-guided stent placement in iliac arterial stenoses: a feasibility study.

PURPOSE: To assess the feasibility of magnetic resonance (MR) imaging-guided stent placement in iliac arterial stenoses. MATERIALS AND METHODS: Thirteen patients with 14 iliac arterial stenoses were examined prospectively. Angioplasty was performed through a femoral sheath by using a conventional 1.5-T MR imaging system. Stents and catheters were visualized on the basis of their artifacts. Nitinol stents were placed with gradient-echo MR imaging guidance. Angioplasty balloons were inflated with gadolinium-based contrast material. Results were evaluated clinically and with both digital subtraction angiography (DSA) and contrast material-enhanced MR angiography. RESULTS: Ten of 13 patients were treated with technical success by using MR imaging-guided intervention alone. Three patients were treated with additional fluoroscopic guidance, because complications (ie, panic attack, subintimal recanalization, and stent misplacement) occurred with MR guidance. The quality of the postinterventional contrast-enhanced MR angiograms of three of 12 lesions with stents was limited owing to stent-induced signal loss of the lumen. The mean stenosis degree after stent placement was significantly higher at contrast-enhanced MR angiography than at DSA (24.6% vs 6.2%). The mean MR imaging-guided procedure time was 74 minutes. CONCLUSION: MR imaging-guided stent placement in iliac arteries is feasible in select patients. The presented technique has limitations-that is, long procedure times, lack of real-time monitoring, and stent artifacts-that necessitate further modifications before it can be recommended for clinical use.

[Percutaneous transpapillary extraction of biliary calculi for symptomatic choledocholithiasisafter unsuccessful endoscopic treatment]. / Perkutane transpapilläre Gallensteinextraktion bei symptomatischer Choledocholithiasis nach frustranem endoskopischen Behandlungsversuch.

PURPOSE: Evaluation of a percutaneous transhepatic treatment of symptomatic choledocholithiasis in bile ducts that cannot be reached with the endoscope. METHODS: From January 1996 to August 2000 a transhepatic extraction of biliary calculus was performed in four patients. Endoscopic retrograde cholangiography (ERC) was not successful in any of the cases. Clinical symptoms were icterus in four cases, additional cholangitis or colics in two cases. First, a balloon dilation of the papilla was performed by a percutaneous transhepatic approach. For removal of bile duct stones, occlusion catheters and Dormia baskets were used. Technical success was defined as complete removal of bile duct stones. Clinical success was defined as normalization of cholestasis and inflammation parameters. In the follow-up an ultrasound examination was performed and blood samples were taken for control of cholestasis parameters. RESULTS: In all four cases treatment was technically and clinically successful. For complete removal of biliary calculus a second intervention was necessary in two cases. In each case an internal to external drainage was left over a mean of 7 days (3-13 days). In the mean follow-up of 30.5 months (6-50 months) all patients had persistent relief of symptoms. No further interventions were necessary. No complications were present. CONCLUSION: Percutaneous transpapillary extraction of biliary calculus is an effective alternative to surgery in patients with bile ducts, that cannot be reached with the endoscope.

On the heating of linear conductive structures as guide wires and catheters in interventional MRI.

The interest in performing vascular interventions under magnetic resonance (MR) guidance has initiated the evaluation of the potential hazard of long conductive wires and catheters. The objective of this work is to present a simple analytical approach to address this concern and to demonstrate the agreement with experimental results. The first hypothesis is that a long conductive structure couples with the electric field of the radio frequency (RF) transmit coil. The second hypothesis is that this coupling induces high voltages near the wire ends. These voltages can cause tissue heating due to induced currents. The experimental results show an increase in coupling when moving a guide wire toward the wall of an RF transmit coil, documented with a temperature increase of a saline solution in close proximity to the tip of the guide wire. The coupling of the wire not only presents a potential hazard to the patient, but also interferes with the visualization of the wire. A safe alternative would be the use of nonconducting guide wires. J. Magn. Reson. Imaging 2001;13:105-114.

Morphology and hemodynamics in dissection of the descending aorta. Assessment with MR imaging.

PURPOSE: To obtain morphologic and functional information in patients with dissection of the descending aorta using contrast-enhanced MR angiography (MRA) and MR blood flow quantification of the true and false lumina. MATERIAL AND METHODS: Fourteen patients were studied prospectively using a 1.5 T unit. MRA was performed with a 3D FISP sequence (TR/TE/flip angle 4.7/1.9 ms/30 degrees) after injection of 0.2 mmol Gd-DTPA per kg b.w. Flow quantification with phase velocity mapping was done at the level of the diaphragm using a 2D FLASH technique (TR/TE/flip angle 28/6.5 ms/30 degrees) with an average temporal resolution of 23 frames per cardiac cycle (34 ms). A spectral broadening index was applied to quantify the amount of flow irregularity within both channels of the aorta. Extension of the dissection and involvement of the major branch vessels were analyzed. RESULTS: The mean flow volume per minute was 1,982 ml (SD 1,083 ml) in the true and 1,052 ml (SD 763 ml) in the false lumen. Average peak-velocities were 98 cm/s (SD 33 cm/s) in the true channel and 47 cm/s (SD 26 cm/s) in the false channel. Ten patients had bidirectional flow in the false lumen with a reflux volume ranging between 6.8% and 98%. Only 1 patient presented with bidirectional flow in the true lumen (reflux volume 15%). A significantly higher degree of flow irregularity was found in the false lumen compared with the true channel. CONCLUSION: Different hemodynamic patterns were found in aortic dissection. Their prognostic value and the impact on therapy, specifically percutaneous interventional procedures, have to be further studied.

[Carotid endarterectomy and carotid stenting. A pilot study of a prospective, randomized and controlled comparison]. / Karotisendarteriektomie und Karotisstenting. Pilotstudie eines prospektiven, randomisierten und kontrollierten Vergleichs.

INTRODUCTION: A prospective, randomized and controlled trial is conducted to compare carotid endarterectomy and carotid stenting in high grade symptomatic carotid artery stenoses. METHODS: According to the study design symptomatic patients with a angiographically high-grade (> or = 70%) internal carotid artery stenosis are included. Pre- and postinterventional diagnostics during the hospitalization period includes neurological assessment, duplex sonography of the cervical and cerebral arteries and magnetic resonance imaging of the brain. Follow-up examinations are scheduled after 1, 6 and 12 months and consist of a neurological assessment and duplex sonography. After 12 months selective angiography and magnetic resonance imaging of the brain will be performed additionally. During a period of 9 months up to now 23/137 patients treated for a carotid artery stenosis were included in the study, 11 patients underwent surgery and 12 patients carotid stenting. RESULTS: Carotid stenting and endarterectomy was primarily successful without residual stenosis > 30% in each patient without the occurrence of stroke or death. In 18 follow-up examinations (neurological assessment including duplex sonography) of 13 patients (13 follow-up examinations after 30 days, 5 after 6 months) no relevant restenosis and no stroke occurred. CONCLUSION: As of yet, carotid stenting was a safe procedure. Due to the small number of patients a definitive conclusion can not be drawn.

Stent appearance at contrast-enhanced MR angiography: in vitro examination with 14 stents.

PURPOSE: To evaluate signal intensity changes influencing assessment of stent patency at contrast material-enhanced magnetic resonance (MR) angiography. MATERIALS AND METHODS: By using an in vitro model, 14 stents-nine nitinol, one tantalum, two stainless steel, and two cobalt alloy-were investigated regarding their appearance at MR imaging. A vascular phantom consisting of tubes filled with 2.00 mmol/L gadopentetate dimeglumine in saline solution was studied in different orientations within the magnetic field. Imaging was performed with a fast three-dimensional gradient-echo sequence (4. 70/1.89 [repetition time msec/echo time msec]). Relative signal intensity reduction within the stents and the degree of artificial narrowing of the stent lumen were calculated. RESULTS: The stent lumen was visible within 13 stents. A total signal void inside the stent lumen appeared in only one cobalt alloy stent. Artificial narrowing of the diameter was less than 33% in 10 of 14 stents. The tantalum stent and four nitinol stents seemed best suited for contrast-enhanced MR angiography. A bandlike artifact occurred at the ends of the stents when positioned along the readout direction. CONCLUSION: To differentiate between artifacts and stenoses, knowledge of the degree of signal intensity reduction and artificial lumen narrowing within vascular stents is essential. Stent geometry, relative orientation to the magnetic field, and alloy composition influence signal intensity alteration within the stent lumen.