PURPOSE:In clinical prospective trials, we examined the effect of the low molecular weight heparin (lmwh) reviparin on restenosis rate after Strecker stent implantation in femoral popliteal arteries.MATERIALS AND METHODS:62 patients were treated between 1992 and 1998. Patients received reviparin, 3500 IU, prior to stent implantation followed by 7500 IU for 24 h (i.v.) and 2 x 1750 IU/day s.c. over three weeks (n = 12) or 10,500 IU for 24 h (i.v.) and 2 x 3500 IU/day s.c. over 3 1/2 weeks (n = 50). Follow-up parameters were clinical symptoms, ankle-brachial index, color Doppler flow duplex sonography, and DSA.RESULTS:Three thrombotic occlusions and three stenoses were observed in the low-dose group. Raising the dose resulted in neither thrombotic nor other events within the first three months. Seven stenoses occurred afterwards up to the 7th month. The complication rate was low: one moderate hematoma and one puncture aneurysm. Primary patency rate was 88% and 80% for one and two years, respectively. This is significantly better than the primary patency rates for patients receiving low-dose lmwh (p < 0.005) or unfractionated heparin (p < 0.05).CONCLUSIONS:Hence, high-dose administration of the lmwh reviparin lowers the restenosis rate after stent implantation in femoropopliteal arteries.

Restenosis and occlusion of atherosclerotic arteries are prevented by a newly developed arterial prosthesis consisting of a pliable and elastic wire mesh tube positioned to the balloon of an angioplasty catheter. As the balloon is inflated the prosthesis dilates and provides the arterial wall with a new mechanical support. This new device was successfully implanted in ten patients having an iliac artery stenosis and improved the therapeutic result of the preceding angioplasty. There were no complications.

Ziele: Zementaugmentationen haben in den letzten Jahren in der Therapie osteoporotischer Sinterungsfrakturen von Wirbelkörpern einen hohen Stellenwert erlangt. Sowohl durch Vertebroplastie als auch durch Kyphoplastie wird eine Stabilisierung der Fraktur sowie eine rasche Schmerzreduktion erreicht. Ziel der Untersuchung war ein Vergleich beider Verfahren bezüglich des Aufrichtungseffektes, der Komplikationen, der subjektiven Patientenzufriedenheit, sowie der Kosten und des Ertrages. Methode: 32 in der Klinik für Radiologie im Jahre 2005 vertebroplastierten Wirbelkörper wurden verglichen mit 32 in der Klinik für Unfallchirurgie kyphoplastierten Wirbelkörper. Indikation für die Intervention war die klinische Symptomatik, bestätigt durch das Vorhandensein eines im MRT nachgewiesenen Knochenödems. Die beiden Gruppen unterschieden sich nicht bezüglich Lokalisation, Typ und Alter der Fraktur, des Vorhandenseins alter Frakturen, sowie der Kyphosewinkel vor und nach Zementaugmentation. Die Patienten wurden 6 Monate nach Intervention befragt bezüglich Zufriedenheit und klinischer Symptomatik im Verlauf. Ergebnis: In der Gruppe der Vertebroplastien konnte bei 9 von 32 Wirbelkörpern (28%) eine Verbesserung der Fehlstellung, also eine Verringerung des Kyphosewinkels erreicht werden, und zwar um 2° bis maximal 10°. In der Gruppe der Kyphoplastien konnte bei 18 von 32 Wirbelkörpern (56%) eine Korrektur erreicht werden, und zwar mit einer Verringerung des Kyphosewinkels um 3° bis maximal 12°. Zementaustritte in Venen oder Bandscheiben, die klinisch nicht signifikant waren, wurden in beiden Gruppen gleich häufig beobachtet. Unterschiede im weiteren Verlauf der klinischen Symptomatik sowie in der Patientenzufriedenheit bestanden zwischen den beiden Gruppen nicht. Die Kosten waren höher für die Kyphoplastie, der finanzielle Ertrag geringer als bei Vertebroplastie. Schlussfolgerung: Sowohl die Kyphoplastie als auch die Vertebroplastie sind sichere Verfahren und geeignet zur Behandlung symptomatischer osteoporotischer Wirbelkörperfrakturen. Bei ausgeprägter kyphotischer Fehlstellung ermöglicht die Kyphoplastie eine effizientere Aufrichtung des Wirbelkörpers.

Ziele: Ermittlung technischer und klinischer Erfolgsrate der Cryoplastie zur Behandlung von symptomatischen Stenosen oder Verschlüssen femoro-poplitealer Arterien. Methode: Zwischen Oktober 2005 und Juli 2006 wurden Femoro-Popliteal-Arterien von 21 Patienten (15m, 6 w; Alter 49–87 Jahre, durchschn. 69) durch Cryoplastie behandelt:

Ziele: Als ein relativ neues Behandlungsverfahren unterliegt die Myomembolisation einer genauen Nachbeobachtung. Leitlinien sind in Bearbeitung. Indikationen und Kontraindikationen sowie interessante, seltene und andere erwähnenswerte Befunde werden vorgestellt. Methode: Zwischen 1999 und 2006 wurden in unserer Abteilung 200 Patientinnen mit symptomatischen Uterusmyomen mit einer Embolisation der myomversorgenden Arterien behandelt und klinisch, sonographisch und, falls indiziert, mit MRT nachuntersucht. Ergebnis: Bei 95% der Patientinnen wurde eine signifikante Reduktion der klinischen Symptome und eine Reduktion der Myom- bzw. Uterus-Größe erzielt. Besondere Nachbeobachtungsbefunde schließen ein: kompliziertes Postembolisationssyndrom mit passagerer hepato-renaler Insuffizienz (1/200); Expulsion nekrotischen Myomgewebes (8/200), davon 5 kombiniert mit Endometritis; erfolgreiche Schwangerschaft (2 Pat.); komplizierte Schwangerschaft mit Uterusruptur und Tod des Fetus (1 Pat.). Schlussfolgerung: Die Myomembolisation ist eine sichere und effektive, minimal-invasive Methode. Es bedarf einer sorgfältigen interdisziplinären Zusammenarbeit zwischen interventionellem Radiologen und Gynäkologen zur Indikationsstellung, Nachbeobachtung und Behandlung seltener Komplikationen. Zusätzlich ist die Aufklärung der Patientin und die Ausbildung des behandelnden Gynäkologen über den post-interventionellen Verlauf und mögliche Komplikationen von großer Bedeutung. Erfolgreiche Schwangerschaften nach Myomembolisation sind möglich.

Two patients with subclavian vein thrombosis are presented in which a balloon venoplasty led to recanalization of the subclavian vein and complete remission of clinical symptoms. In patients with extreme symptoms and unsuccessful initial catheter-directed local thrombolysis, this non-operative approach can be considered despite known favourable spontaneous outcome of subclavian vein thrombosis.

Radiation risk has to be justified and optimised. This study discusses the radiation risk of uterine artery embolisation (UAE) for the treatment of fibroids. A total of 70 consecutive UAE dosimetry parameters were assessed. Using Monte Carlo simulation, organ and effective doses and dose conversion coefficients (DCCs) (mSv Gy cm(-2)) were calculated. During UAE optimisation, avoidance of oblique views and use of last-image-hold (LIH) documentation instead of digital subtraction angiography (DSA) were investigated. Mean dose-area product (DAP) was 37.1 Gy cm(2) (median 23.7 Gy cm(2)) and mean fluoroscopy time was 18.4 min (median 16.6 min). Dose values decreased as the study progressed: mean DAP for patients 1-21, 68.5 Gy cm(2); patients 22-43, 35.7 Gy cm(2); and patients 44-69, 13.0 Gy cm(2). Average DCC for DSA image procedures was 0.572, yielding a mean effective dose of 29.6 mSv (median 17.1 mSv). For LIH-only procedures, an average DCC of 0.813 was estimated [using mean effective dose: 10.6 mSv (median 8.1 mSv)].

Ziele: Die Offenheitsrate mit herkömmlichen Stents behandelter Femoro-Popliteal-Arterien nach ungenügendem PTA-Ergebnis ist unbefiedigend,dies ist unter anderem durch die verwendeten geschlitzten selbstexpandierenden Rohrstents begründet,die sich den besonderen anatomischen Gegebenheiten der femoropoplitealen Gefäße nicht anpassen. Deshalb sind neue technische Konzepte notwendig. Methode: 12 Patienten mit einer pAVK Stadium IIb bis III nach Fontaine bedingt durch Stenosen im femoropoplitealen Bereich wurden durch Dissektionen bedingten Reststenosen mit einem Stenosegrad von über 40% mit Nitinol-Helix-Stents behandelt. Hierzu wurden verschiedene Stenttypen verwendet wie Doppelcoil-Stents,Mäander-Stents und Helix-Stents, die als gestrecktes Drahtfilament durch einen Katheter geschoben werden und sich zum intravasalen tubulären Stent formen. Ergebnis: Bei allen 12 Patienten konnte der Stent durch den liegenden 5-F-Katheter platziert werden. Akute Komplikationen wie Thrombose und Embolie sind nicht aufgetreten. Die angiographischen Kontrollen bis zu einer Beobachtungszeit von 26 Monaten zeigten bislang keine Re-Verschlüsse. Der Zeitaufwand und Strahlenbelastung ist vergleichbar mit den üblichen Stents. Schlussfolgerung: Die konzeptierten Helix-Stents sind zuverlässig und sicher zu platzieren. Sie erfüllen die technischen Forderungen: Sie sind flexibel, komprimierbar,longitudinal stauchbar und rotierbar. Ermüdungsbrüche wie bei selbst-expandierenden tubulären Nitinol-Stents sind nicht zu erwarten.

The goal of this study was estimation of patient effective dose from uterine artery embolization of leiomyomata. Parameters and data relevant to patient dose were recorded for 33 consecutive procedures. Using Monte Carlo simulation of radiation transport, organ and effective doses were calculated in detail for a subset of five procedures, to estimate the effective dose for all procedures. Mean dose area product was 59.9, median 23.4, and range 8.8-317.5 Gycm(2). Mean absorbed ovarian dose was calculated as 51 mGy in the five procedures. Using the dose conversion factor estimated from the Monte Carlo simulation for all procedures a mean estimated effective dose of 34 mSv (median 13 mSv, range 5-182 mSv) results, with a tendency to lower values regarding the succession of the procedures. Patients' radiation exposure level is up to twice of that of an abdominal CT examination. Angiographic equipment related dose-reducing features and radiographic technique essentially influence organ doses and effective dose. Consistent application of dose-reducing techniques and awareness of radiation exposure justifies uterine artery embolization as a therapeutic option for the treatment of uterine fibroids.

Ziele: Konventionelle Stents sind röhrenförmige Teile, die mit einem kleinen Durchmesser in das Gefäß eingeführt werden und sich am Zielort radial aufdehnen. Um die Einführgröße zu reduzieren, wurde ein neues Stent-Design entwickelt, das auf einem Helix-Prinzip beruht. Technische Eigenschaften wurden in Experimenten und ersten klinischen Anwendungen überprüft. Methode: Ein einzelnes oder mehrere Metallfilamente werden im gestreckten Zustand durch einen kleinen Katheter ins Gefäß eingeführt und bilden eine Stent-ähnliche Struktur erst am Zielort aus. Verschiedene Designs für die Behandlung von peripheren Arterien (n=17), sowie ein membran-haltiges Implantat welches in Kombination mit bilateralen aorto-iliacalen Stentgrafts Aortenaneurysmen (AAA)(n=13) ausschließt, wurden in Tierversuchen getestet unter Erhebung angiographischer und histomorphologischer Befunde. Erste Anwendungen an Patienten wurden durchgeführt. Ergebnis: Alle Stents ließen sich technisch erfolgreich implantieren. Der Einführdurchmesser liegt bei 4 bis 5F für periphere Stents und 9 F für AAA-Stents. Ein peripherer Stent zeigte einen thrombotischen Frühverschluss. Mit dem Membran-Stent konnten die AAA vom Blutstrom ausgeschlossen werden, wobei der Blutfluss in die Peripherie durch die aorto-iliacalen Stentgrafts erhalten wurde. Histomorphologisch zeigte sich eine nur geringe Intimahyperplasie bei Untersuchungszeiträumen von bis zu 12 Monaten. Erste Resultate an Patienten sind vielversprechend. Schlussfolgerung: Diese neuen Entwicklungen vom Typ Helix-Stent haben einen sehr geringen Einführdurchmesser, der vom Maximaldurchmesser unabhängig ist. Im Vergleich mit konventionellen Stents haben sie eine höhere Flexibilität, speziell longitudinale Flexibilität, bessere Rotationseigenschaften, und sie bestehen aus weniger Metallmaterial. Sie scheinen daher besonders geeignet zu sein für schwer behandelbare, kleine und gewundene Arterien, insbesondere periphere Gefäße, Ober- und Unterschenkelarterien.

In clinical radiological practice two main questions regarding image quality have to be looked at: Which degree of image quality is needed? and: How can this image quality be objective? Image quality requirements depend on size, density and contrast of the objects of interest and on the clinical question which has to be answered. In comparison to conventional radiography, the digital radiographic techniques offer additional features concerning optimisation of image quality and dose, like a wider dynamic range, digital fluoroscopic techniques and post-processing. Therefore it is necessary to define new quality criteria for these techniques. In the following, typical examples demonstrate the development of the 'Diagnostic Requirements for Digital Radiographic Procedures'. These examinations include projection radiographs with digital luminiscent radiography, fluoroscopic procedures with digital image intensifier radiography and angiographic procedures with digital subtraction angiography. The clinical question of a radiological examination also forms the background to optimisation strategies considering image quality and radiation dose.

The aim of this study was to determine long-term success of flexible tantalum stents for the treatment of ostial and truncal renal artery stenosis. Since 1989, flexible tantalum stents (type Strecker) were implanted in 34 patients (36 arteries, 25 ostial lesions, 11 truncal lesions) with uncontrollable renovascular hypertension, 9 of them in association with renal insufficiency. Stents were placed unilaterally in 32 patients, and bilaterally in 2 patients for the treatment of renal artery stenosis. Thirty-five of 36 lesions were atherosclerotic, including 5 recurrencies after previous percutaneous transluminal renal angioplasty (PTRA). One patient had Takayasu arteritis. Stents were implanted after unsuccessful PTRA of 11 truncal and 23 ostial lesions, and as a primary procedure in 2 ostial lesions. Follow-up examinations included blood pressure measurement, determination of serum creatinine level, color duplex sonography, or angiography. The technical success rate was 92 %. Technical failure included incorrect stent placement (1 of 36 lesions, 2.8 %), and stent dislocation (2 of 36 lesions, 5.6 %), and two stents were retrieved percutaneously. In one case of Takayasu arteritis, residual stenosis of 40 % was observed. After technically successful stent placement, 77 % of patients became normotensive with or without medication. In the remaining patients there was partial improvement with blood pressure between 140 and 180 mmHg. Renal function improved in 76 % of patients (completely in 3 of 8, 38 %; and partially in 3 of 8, 38 %). Primary patency rate including all stented lesions and initial technical failures was 82.4 % ± 6.8 (1 year) and 82.4 % ± 9.2 (3 years). After technically successful stent placement, patency rates were 89.9 ± 5.6 % (1 year), and 89.9 ± 7.6 % (3 years). For ostial lesions, primary patency rate was 87.9 ± 6.7 % (1 year) and 87.9 ± 9.2 % (3 years). Placement of flexible tantalum stents in renal arteries is technically demanding, especially in ostial lesions. Once placed successfully, stent patency rate is excellent.

Purpose: In clinical prospective trials, we examined the effect of the low molecular weight heparin(lmwh) reviparin on restenosis rate after Strecker stent implantation in,femoral popliteal arteries. Materials and Methods: 62 patients were treated between 1992 and 1998. Patients received reviparin, 3500 IU, prior to stent implantation followed by 7500 IU for 24 h (i.v.) and 2 x 1750 IU/day s.c. over three weeks (n = 12) or 10500 IU for 24 h (i.v.) and 2 x 3500 IU/day s.c. over 31/2 weeks (n = 50). Follow-up parameters were clinical symptoms, ankle-brachial index, color Doppler flow duplex sonography, and DSA. Results: Three thrombotic occlusions and three stenoses were observed in the low-dose group. Raising the dose resulted in neither thrombotic nor other events within the first three months. Seven stenoses occurred afterwards up to the 7th month. The complication rate was low: one moderate hematoma and one puncture aneurysm. Primary patency rate was 88% and 80% for one and two years, respectively.. This is significantly better than the primary patency rates for patients receiving low-dose lmwh (p <0.005) or unfractionated heparin (p <0.05). Conclusions: Hence, high-dose administration of the lmwh reviparin lowers the restenosis rate after stent implantation in femoropopliteal arteries.

Since the introduction of open metallic stents for the treatment of peripheral arterial disease in 1987, percutaneous intravascular stent implantation has become a valuable adjunct to balloon angioplasty and a widely-accepted method of treatment. The availability of long-term data helps to define the indications for this treatment regimen and the risk factors for stent failure. With growing experience in stent therapy and other interventional techniques, new indications have been developed. Long-term vascular patency, the main goal of stent implantation, seems to depend on the characteristics of the underlying lesion. For the prevention of early stent thrombosis and neointimal hyperplasia, which are the major causes of stent failure, there are different ideas and new developments, including e.g, different stent designs, peri- and postprocedural medication, local intravascular drug therapy, intravascular brachytherapy and radiating stents. Thus, vascular stenting remains a steadily expanding field in interventional radiology.

Pulsed fluoroscopy is an important too for dose reduction in fluoroscopic procedures. Evaluation of image quality and dose is necessary to optimise this technique. Image quality was evaluated for a grid controlled (Philips Diagnost 97) and a generator controlled (Siemens Sireskop SX 40) pulsed fluoroscopic system by phantom measurements and in routine clinical use. Spatial resolution and low contrast detectability were assessed in moving phantoms and under static conditions. Dose measurements were performed at the image intensifter entrance. For clinical aspects quality of last image hold (LIH) images of clinical examinations taken from pulsed and continuous fluoroscopy were graded in comparison to single shot exposures. Dose rate could he reduced to 10-46% of the contmuous mode. Detectability of low contrast objects and spatial resolution were improved in moving objects in pulsed fluoroscopy. Quality of LIH images of pulsed fluoroscopy was graded to be superior in comparison to the continuous mode. By suitable combinations of pulse frequency and pulse dose, reduction ion of radiation exposure and improvement of image quality can be achieved.

PURPOSE The relations between image quality in last image hold images and dose in grid controlled fluoroscopy in comparison to the continuous mode need to be characterised and recommendations for the clinical application of this technique should be given. MATERIAL AND METHODS Spatial resolution, signal-noise ratio and, contrast-detail visibility were evaluated by phantom measurements in grid controlled pulsed and continuous fluoroscopy. Dose was measured at the image intensifier entrance. Image quality of last image hold (LIH) images of clinical examinations was graded in relation to single shot exposures. RESULTS Signal-noise ratio and contrast-detail visibility depend on the dose per puls. Spatial resolution and contrast-detail visibility in grid controlled fluoroscopy are superior than to in the continuous mode. Image quality of the LIH images from the grid controlled fluoroscopy was improved. Radiation exposure could be reduced to 10-46%. CONCLUSIONS Combinations of puls-dose and -frequency are recommended for achieving extensive dose reduction and improved image quality of LIH images.

The function and safety of a percutaneously implantable catheter-port system were studied in 44 patients with different diseases (32 patients with malignant disease, 11 with peripheral arterial disease, and one with recurrent asthmatic attacks). Most patients required repeated local-regional arterial infusion. Infection (two patients) and catheter-related complications (10 patients) were observed during the follow-up period (maximum length of follow-up, 542 days; mean, 177 days). Port migration or leakage did not occur. The data suggest that this new catheter-port system is safe and easy to handle.

PURPOSE:To evaluate the long-term success of femoropopliteal artery stent placement after technical failure of balloon angioplasty and to determine potential factors predictive of stent failure.MATERIALS AND METHODS:In 80 patients, flexible tantalum stents were implanted for treatment of residual stenosis greater than 30% after balloon angioplasty of femoropopliteal artery stenoses (n = 33) or occlusions (n = 47). Follow-up examinations were performed at 1-72 months to evaluate early and late stent failure according to risk factors such as lesion type, anatomic location, stent length, runoff quality, and restenosis after balloon angioplasty.RESULTS:Early stent thrombosis occurred within 10 days after stent placement in four (5%) patients; the frequency was higher (P < .01) in stents longer than 4 cm (14%) versus that in stents 4 cm or shorter (2%). For all stents, the 2-year primary patency rate was 51% and the 3-year rate was 48%. The 2-year primary patency rate was significantly better (P < .05) for shorter stents (59%) versus that for longer stents (30%) and for treated stenoses (73%) versus treated occlusions (33%). Multivariate analysis revealed that lesion type and lesion length were the most reliable factors predictive of stent failure.CONCLUSION:Successful stent therapy does not seem to depend on the type of stent used but rather on lesion type, lesion length, and other predisposing factors.

METHODS:The dose needed for high image quality in l.a. DSA, was determined by investigation of the necessary relationship between dose and image quality. This method is based on measurements of the signal-to-noise ratio and of the contrast-detail detectability. It has been tested on two different systems (Philips integris V3000, Philips Diagnost 97).RESULTS:Our measurements prove that an image intensifier entrance dose of 1.1 microGy (image intensifier diameter 38 cm) is sufficient for high image quality in DSA. An increased dose value does not lead to an improvement in image information. For details larger than the pixel size the 512 matrix produces a higher signal-to-noise ratio with a higher contrast-detail detectability, whereas higher spatial resolution results by the use of a 1024 matrix. In rotational angiography, high image quality can be achieved at an image intensifier entrance dose of 1.1 microGy. In contrast to sequences without rotation, image quality is decreased through movement unsharpness. As the maximum exposure time 25 ms should be selected. The use of a 1024 matrix does not lead to a better spatial resolution in rotational angiography.

PURPOSE:To evaluate the long-term success of tantalum stents implanted in iliac artery lesions and to determine potential predictive factors of early and late stent failure. MATERIALS AND METHODS:In 289 patients, flexible tantalum stents were implanted in iliac artery stenoses (n - 223) or occlusions (n - 66). Early and late stent failures were evaluated at 1-79 months (mean, 23 months). Four risk factors were evaluated: lesion type (occlusion vs stenosis), lesion location (common vs external iliac artery), lesion length (< 4 vs > 4 cm), and quality of runoff (good vs poor). RESULTS:The frequency of early stent thrombosis was significantly (P < .001) higher in occlusions (15.2%) versus stenoses (2.7%), in external (12.8%) versus common (1.1%) iliac arteries, in long (16.7%) versus short (0.5%) lesions, and in poor (14.0%) versus good (2.1%) runoff. At multivariate analysis, runoff and location were influencing factors. Primary patency rates at 3 and 5 years were 85% and 70%, respectively, for all stents. Three-year patency rates were significantly higher in short (88%) versus long (63%) lesions and in stenoses (92%) versus occlusions (63%). At multivariate analysis, lesion length was the only predictive factor for 3-year stent patency. CONCLUSION:Stent implantation offers valuable long-term treatment for atherosclerotic iliac artery disease. Success can be predicted on the basis of risk factors.