[Long-term results after balloon angioplasty of the crural artery]. / Langzeitergebnisse nach Ballonangioplastie kruraler Arterien.

PURPOSE: To evaluate the technical success rate, procedure-related complications, and clinical long-term results for patients who underwent infrapopliteal angioplasty. MATERIALS AND METHODS: We retrospectively evaluated all patients who underwent infrapopliteal angioplasty to treat critical chronic limb ischemia or severe claudication from 1/1997 to 12/1999. We excluded patients with acute (< 2 weeks) limb ischemia. Procedure-related data were prospectively documented in a database and analyzed with a focus on the technical success rate and procedure-related complications. In addition all clinical documents were analyzed, and a follow-up examination was performed or telephone interviews were conducted with patients, relatives and referring doctors for follow-up. The primary end points were the limb salvage rate and patient survival rate. The secondary end points included the complication rate, technical success rate, and walking distance. RESULTS: 112 patients with a mean age of 72 years (41 women, 71 men) underwent crural angioplasty on 121 limbs. Four patients suffered from severe claudication (Rutherford category 3) and all others had critical chronic limb ischemia (category 4 to 6). The complication rate was 2.7 %. The technical success rate was 92 %. The ankle brachial index increased from 0.59 to 0.88. The mean walking distance increased significantly from 52 +/- 66 to 284 +/- 346 meters at the time of follow-up. The limb salvage rate was 83.6 % after one year and 81.1 % after three years. The mean survival rate according to Kaplan-Meier was 79.4 %, 69.2 %, and 54.2 % at 1, 2, and 3 years, respectively. Patients with at least one patent run-off vessel after angioplasty had a significantly better limb salvage rate. Diabetes was not a risk factor for limb salvage. CONCLUSION: Infrapopliteal angioplasty shows a high technical success rate with an acceptable complication rate. The clinical long-term success seems favorable if a least one open run-off vessel was able to be achieved. However, the survival rate was limited by the co-morbidity in this patient group.

[Treatment of malignant biliary occlusion by means of transhepatic percutaneous biliary drainage with insertion of metal stents--results of an 8-year follow-up and analysis of the prognostic parameters]. / Behandlung der malignen Gallenwegsstenose mittels perkutaner transhepatischer Metallendoprothesenimplantation: 8 Jahres-Ergebnisse und Analyse prognostischer Faktoren.

PURPOSE: To analyze outcome and predictive factors for patient survival and patency rates of unresectable malignant biliary obstruction treated with percutaneous transhepatic insertion of metal stents. MATERIALS AND METHODS: This is a retroslective analysis of 130 patients treated in one interventional radiological center with data collected from patient records and by telephone interviews. The procedure-related data had been prospectively documented in a computer data base. The Kaplan-Meier analysis was performed for univariate and multivariate comparison of survival and patency rates with the log-rank test used for different tumor types. Predictive factors for survival and 30-day mortality were analyzed by a stepwise logistic regression. RESULTS: Underlying causes of malignant biliary obstructions were cholangiocarcinoma in 50, pancreatic carcinoma in 29, liver metastases in 27, gallbladder carcinoma in 20, and other tumors in 4 patients. The technical success rate was 99 %, the complication rate 27 % and the 30-day mortality 11 %. Primary patency rates (406 days with a median of 207 days) did not differ significantly for different tumor types. The survival rates were significantly (p = 0.03 by log-rank test) better for patients with cholangiocarcinoma than for patients with pancreatic carcinoma and liver metastases. Multiple regression analysis revealed no predictive factor for patient survival and 30-day mortality. CONCLUSION: Percutaneous transhepatic insertion of metal biliary endoprostheses offers a good initial and long-term relief of jaundice caused by malignant biliary obstruction. Although survival rates for patients with cholangiocarcinoma are better than for other causes of malignant biliary obstruction, a clear predictive factor is lacking for patients undergoing palliative biliary stent insertion.

Multiplanar reconstructions and three-dimensional imaging (computed rotational osteography) of complex fractures by using a C-arm system: initial results.

With use of a calibrated angiographic C-arm system and a postprocessing workstation, the authors acquired volume data sets from two-dimensional digital projection images obtained during a C-arm rotation around the patient axis. Multiplanar reconstruction and three-dimensional images of complex fractures were reconstructed and compared with spiral computed tomographic studies in a cadaveric pig study and in eight patients. Computed rotational osteography provided high-resolution multiplanar reconstruction and three-dimensional images of complex fractures.

CT-fluoroscopy: Tool or gimmick?

Recent advances in CT scanner technology and computer hardware have led to the development of CT fluoroscopy (CTF), which allows real-time acquisition and display of cross-sectional images (with a rate of up to 8 frames per second). Since the introduction of the first CT fluoroscopy scanner in 1993, a variety of these scanners have been installed world-wide and many reports on the clinical use of this device have appeared recently. However, use of this new technology for the guidance of interventional radiologic procedures, such as percutaneous biopsy and percutaneous drainage, is not uniformly advocated by interventional radiologists. Concerns have been reported regarding radiation exposure and outcome of the procedures when compared with sequential CT guidance or other alternative guiding modalities. This article is intended to present an overview of CTF technology, to summarize the results of published papers on various interventional applications and to reflect on its specific advantages and disadvantages.

Comparison of C-arm CT fluoroscopy and conventional fluoroscopy for percutaneous biliary drainage procedures.

PURPOSE: To conduct a prospective randomized evaluation of C-arm computed tomography (CT) fluoroscopy for external biliary drainage procedures in comparison with conventional fluoroscopic guidance to reduce the number of transhepatic punctures as a primary endpoint. MATERIALS AND METHODS: In 18 patients with biliary obstructions, 20 external percutaneous biliary drainage procedures were prospectively performed with use of either C-arm CT fluoroscopy or conventional fluoroscopy alone. The number of hepatic punctures, procedure time, and fluoroscopy time, were analyzed separately for both methods. RESULTS: C-arm CT fluoroscopy resulted in a reduced number of transhepatic punctures, with decreased procedure and fluoroscopy times (P < .05; t test). When compared with conventional external biliary drainage procedures, a mean of 1.8+/-1 versus 4.8+/-2.8 hepatic punctures at a fluoroscopy time of 3.4+/-1.5 versus 11.4+/-7.4 minutes was required for C-arm CT fluoroscopy, while procedure times were 11+/-3.6 versus 16.2+/-9.3 minutes. CONCLUSIONS: C-arm CT fluoroscopy is associated with decreased procedure and fluoroscopy times, while fewer transhepatic punctures are required to establish external biliary drainage.

Feasibility of C-arm-supported CT fluoroscopy in percutaneous abscess drainage procedures.

PURPOSE: Evaluation of C-arm-supported CT fluoroscopy to facilitate percutaneous abscess drainage procedures. METHODS: Prospectively, 40 percutaneous drainage procedures were performed either with C-arm-supported CT fluoroscopy or with CT fluoroscopy alone. Hybrid imaging was performed on the CT couch after complementing a CT fluoroscopy scanner with a C-arm fluoroscopy unit. Procedure times, drainage revisions during follow-up, and postinterventional drainage periods were analyzed. RESULTS: When compared with exclusive CT fluoroscopic guidance, a median procedure time of 9 +/- 3.7 min versus 14.8 +/- 7.3 min was required for C-arm-supported CT fluoroscopy (p < 0.005, t-test). During follow-up, eight drainage catheters had to be revised within the exclusive CT fluoroscopy group, while only two revisions were necessary within the C-arm-supported CT fluoroscopy group. With C-arm-supported CT fluoroscopy, postinterventional drainage periods were reduced (median 13 vs 19 days; p < 0.001, t-test). CONCLUSION: Compared with exclusive cross-sectional image guidance, C-arm-supported CT fluoroscopy seems to improve placement of abscess drainage catheters to possibly reduce procedure times, drainage catheter revisions, and postinterventional drainage periods.

The influence of radiation and chemotherapy-related DNA strand breaks on carcinogenesis: an evaluation.

PURPOSE: DNA strand breaks are believed to induce carcinogenesis. This study was conducted to analyze induction and repair of irradiation- and chemotherapy-related strand breaks in vitro. METHODS: Friend Leukemia cells were exposed to irradiation and various chemotherapeutic agents at different doses and concentrations. Occurrence of strand breaks was determined fluorometrically, measuring the rate of DNA unwinding immediately after exposure and 24 hours later. RESULTS: The amount of double-stranded DNA decreased significantly for irradiation, doxorubicin, dactinomycin and etoposide (p < or = 0.05, t-test). After 24 hours free of exposure, the persistent damage was detectable for all of these agents but not for irradiated cells, with DNA strand breaks being decreased for etoposide, unchanged for doxorubicin and increased for methotrexate as well as for dactinomycin. CONCLUSIONS: Severe DNA damage is induced by various chemotherapeutic agents and by irradiation. While repair of chemotherapy-related strand breaks may remain incomplete or prolonged for some chemotherapeutic agents, repair of radiation induced strand breaks is faster and more complete. Therefore chemotherapy-related carcinogenesis may partially be explained by prolonged persistence of DNA strand breaks.

[Pulmonary, nodular cavernous, calcifying form of amyloidosis]. / Pulmonale, noduläreinschmelzende, kalzifizierende Form der Amyloidose.

We report a rare case of pulmonary nodular amyloidosis featuring all typical morphologic alterations associated with this disease; multiple amyloidomas, calcification and cavernous transformation were present. Definite diagnosis was established histologically with CT-guided biopsy. The different types of pulmonary amyloidosis and their radiological appearances are described and discussed.

Effects of nitinol Strecker stent placement on vascular response in normal and stenotic porcine iliac arteries.

PURPOSE: This experimental study was conducted to evaluate neointimal thickness, lumen diameters, and histologic changes in normal and stenotic porcine iliac arteries following placement of self-expanding nitinol Strecker stents. MATERIALS AND METHODS: Neointimal trauma causing slight vascular stenosis was induced unilaterally within external iliac arteries of 12 swines by means of endothelial abrasion and high cholesterol diet. Nitinol Strecker stents were placed within the stenotic and the normal contralateral vascular segments. For histopathologic evaluation, the pigs were killed 12 or 24 weeks after stent placement and luminal diamters were evaluated angiographically. RESULTS: Excluding one occlusion, 15% narrowing of the lumen diameter was induced unilaterally (P = .002). Initial luminal gain after stent placement was greater for stenotic than for normal arteries. The amount of neointima thickness was not different between stenotic and normal vessels (P > .05). Comparing vascular diameters before stent placement and at follow-up, luminal loss due to neointima proliferation was 22% within normal arteries (P = .0002), while a luminal gain by 15% was found within the stenotic arteries (P = .008). Maturation of neointima and endothelial coverage were complete after 24 weeks. CONCLUSIONS: Even though nitinol Strecker stents induce excessive neointimal proliferation, stenotic arteries seem to profit from great early luminal gain resulting in 15% of vascular expansion at follow-up while slight stenosis is induced within normal iliac arteries.

[Control of percutaneous biopsy with CT fluoroscopy]. / Steuerung von perkutanen Biopsien mittels CT-Fluoroskopie.

PURPOSE: Clinical evaluation of CT fluoroscopy and comparison with conventional CT guidance for monitoring of non-pulmonary percutaneous biopsy procedures. MATERIALS AND METHODS: 20 non-pulmonary CT-guided biopsy procedures were prospectively performed either with CT fluoroscopy or with conventional CT guidance. CT fluoroscopy was performed using 120 kV and 50, 70 or 90 mA at a frame-rate of three or six images per second. Number of punctures and biopsies, procedure times, radiation doses and histologic results were analyzed separately for conventional CT guidance and for CT fluoroscopy. RESULTS: With CT fluoroscopy, yield of biopsies was improved (p = 0.005, t-test) and procedure times were shorter than for conventional CT guidance (11.4 +/- 6.0 vs. 23.6 +/- 13.8 min; p = 0.03, t-test). Analysis of procedure related radiation exposure and histologic outcome showed no significant difference between conventional and fluoroscopic CT-guided procedures (p > 0.05, t-test). CONCLUSIONS: CT fluoroscopy facilitates guidance of percutaneous biopsy procedures. Compared to conventional CT assistance, procedure times are decreased while yield of biopsies is improved.

[Postoperative imaging of synthetic coronary artery bypass graft patency by means of CT angiography]. / Postoperative Darstellung von synthetischen Koronararterien-Bypasses mittels CT-Angiographie.

PURPOSE: CT angiography was performed in 12 patients with insufficient autologous graft situations to evaluate postoperative patency and situation of the proximal, distal and coronary artery anastomoses of synthetic Perma-Flow coronary artery bypass grafts. METHODS: Bypass grafts were evaluated postoperatively with spiral CT of the mediastinum. At a flow rate of 3 ml/s, 120 ml of contrast material were applied over a cubital vein. Slice thickness was 3 mm, maximum pitch factor 2 and image reconstruction was performed at 2 mm increment. Shaded surface displays were analysed together with axial scans for bypass evaluation. RESULTS: 8 out of 12 synthetic bypasses proved to be patent. One bypass was completely occluded and in three patients the distal portions of the grafts were occluded. Coronary angiography performed in one case confirmed complete bypass occlusion. Due to the occlusions, 8 distal and 12 proximal anastomoses were visible. Only 8 out of 19 side-to-side coronary artery anastomoses could be sufficiently well imaged with this technique. CONCLUSIONS: CT angiography is suitable for postoperative screening of synthetic coronary bypasses to determine the patency and anastomotic situations. Coronary artery anastomoses however are not sufficiently imaged and coronary angiography continues to be required.

[Pitfalls when using a contrast media injector in MRI]. / Fehlerquellen beim Einsatz eines Kontrastmittelinjektors in der MRT.

PURPOSE: Using a power injector to applicate Gd-DTPA we found a contrast enhancement of the pyelo-caliceal system even in the native studies, and hence we analysed pitfalls when using power injectors in MRI. MATERIAL AND METHODS: We used a power injector Spectris (MedRad, Maastricht, Netherlands). In vitro artifacts were achieved by the mixture of contrast media and saline solution. We substituted contrast media by red water, NaCl by clear water. RESULTS: Using power injectors in MRI, some pitfalls must be avoided, which can render investigations useless, especially dynamic contrast-enhanced investigations. CONCLUSION: In our study we showed an easy way to overcome some pitfalls and use a power injector in MRI in a diagnostically helpful way. The simple use of valves inhibits the mixture of contrast media and saline solution.

[Magnetic resonance phlebography (MRP) of the abdomen and pelvis]. / Magnetresonanzphlebographie (MRP) des Abdomens und des Beckens.

PURPOSE: To evaluate the image quality of magnetic resonance venography (MRV) of pelvic and abdominal veins. METHODS: A retrospective analysis of all MRV between 1993 and 1996 was conducted. A 2D-FLASH-TOF without breath hold and with arterial presaturation was used. All venous segments have been assessed for the quality of visualisation and an overall image quality was determined. 43% of our patients had malignant disease and phlebothrombosis had already been diagnosed in 64%. RESULTS: 126 examinations and 1696 venous segments were analysed. The overall quality of the examination was good, however one examination was non diagnostic because of motion artefacts. Vessels along the vertical axis were good visualised in over 90%. Most important reasons for insufficient visualisation were breathing, motion and metal artefacts as well as compression and displacement of veins due to tumour disease. CONCLUSIONS: Magnetic resonance venography without breath hold TOF technique is practical and robust for routine clinical applications.

Correlation of flow velocity measurements by magnetic resonance phase contrast imaging and intravascular Doppler ultrasound.

RATIONALE AND OBJECTIVES: The authors compare the magnetic resonance (MR) phase contrast flow velocity measurements in varying concentric stenoses with invasive measurements obtained with a Doppler guidewire. METHODS: Flow velocity measurements were obtained using a calibrated 0.018 inch 12 MHz Doppler guidewire and a 1.0 T MR imaging system in a pulsatile hydraulic model with variable arterial stenoses. Velocity measurements were performed proximal, intrastenotic, and distal to the stenoses. The cross-sectional area of stenosis was calculated from the data of both methods. For MR imaging measurements, fast low-angle shot two-dimensional phase contrast sequences with different velocity encodings were used. RESULTS: Phase contrast flow measurements correlated well (r = 0.95, Pearson) with Doppler guidewire-based flow velocity data. Generally, flow velocities obtained with MR imaging were lower when compared with the Doppler-based data (P < or = 0.001, Wilcoxon matched pairs test). However, the ratios and the calculated cross-sectional area of stenoses showed a high correlation (r = 0.96) with the predefined area of stenoses. CONCLUSIONS: The assessment of flow alterations in vitro due to variable stenoses using MR phase contrast flow measurements is very well correlated with the Doppler guidewire. Consequently, these results required in vivo measurements of atherosclerotic lesions to evaluate the clinical impact.

The precise determination of vascular lumen and stent diameters: correlation among calibrated angiography, intravascular ultrasound, and pressure-fixed specimens.

PURPOSE: Luminal diameters measured in vivo by calibrated-catheter angiography and by intravascular ultrasound were correlated with those obtained from pressure-fixed histologic cross-sections to determine the accuracy of both methods. METHODS: Angiographic and endosonographic diameter measurements were performed in the center of stents placed in the iliac arteries of 10 miniature pigs and were compared with luminal and stent diameters in postmortem, pressure-fixed, histologic cross-sections from identical locations. RESULTS: Compared with histologic diameters, magnification-corrected angiographic measurements still magnified vascular luminal diameters by 0.7 +/- 0.71 mm (r = 0.41, Pearson; p < 0.003, Wilcoxon, matched pairs), whereas intravascular ultrasound measurements proved to be almost identical to the histologic lumina (r = 0.95, Pearson; p > 0. 5, Wilcoxon, matched pairs). Similarly, stent diameters correlated well between endosonographic and histologic measurements (r = 0.91; p = 0.002), and less well between angiographic and histologic diameters (r = 0.62; p = 0.002). CONCLUSION: Since calibrated angiography still overestimates vascular lumina, endosonography is the preferred technique for accurate in vivo measurements.

Local intraarterial thrombolysis: in vitro comparison of various infusion catheters.

PURPOSE: Catheters are compared in vitro to evaluate the efficacy of thrombolysis during urokinase infusion within the thrombus. METHODS: Six catheters were introduced individually into human thrombus within a stenotic flow model. Urokinase was infused continuously into the thrombus. To quantify the efficacy of thrombolysis, pressure gradients were recorded proximal and distal to the thrombus and during the course of infusion. Uniformity of lysis was assessed radiographically. RESULTS: The fastest and most homogeneous thrombolysis was achieved with the EDM and the straight-flush catheter, shown by decreasing transthrombotic pressure gradients. All other catheter designs showed less homogeneous and delayed thrombolysis (p 0.7). CONCLUSION: The EDM catheter and the straight flush catheter achieved the most homogeneous and fastest thrombolysis, apparently due to the best urokinase distribution within the thrombus.

[In vitro evaluation of the intravasal Doppler guide wire: determination of hemodynamic effects of stenoses in a flow model]. / In-vitro-Evaluation des intravasalen Doppler-Führungsdrahtes: Bestimmung der hämodynamischen Auswirkungen von Stenosen in einem Flussmodell.

PURPOSE: In a pulsatile hydraulic model, haemodynamic changes caused by stenoses were assessed using an intravascular Doppler guide wire. MATERIAL AND METHODS: In defined stenoses (25, 50, 75 and 87.5% diameter ratio), and with and without collateral flow, a 0.018 inch (0.46 mm) 12 MHz Doppler guide wire was assessed. Flow velocity measurements were taken 20 mm proximal, in, and 20 mm distal to the stenoses. Average peak velocity (APV) and ratios of pre-/poststenotic velocities and pre-/intrastenotic velocities of APV were compared with the grade of stenosis. The degree of the stenosis calculated by the ratio of the cross-sectional area, using the pre- and intrastenotic APV, was correlated with the actual stenosis. RESULTS: The intrastenotic APV increased significantly (APV proximal to the stenosis 15.15 +/- 4.5 cm/s, intrastenotic APV 134.8 +/- 130.9, p < 0.01, Wilcoxon-Mann-Whitney test). The difference between APV pre- and poststenotic was not significant (p > 0.5). Concerning the grade of stenosis the ratio APV pre-/intrastenotic and the consecutively calculated cross-sectional area stenoses was the best predictor (correlation with the known cross-sectional area stenosis r = 0.94 Pearson). CONCLUSION: Using the Doppler guide wire, APV measurements pre- and intrastenotic enable a reliable quantification of the grade of stenosis. The stenosis calculated via the cross-sectional area correlates significantly with the actual stenosis.

[Severe calcifying atherosclerosis of the thoracic aorta with symptoms of aortic isthmus stenosis. Case report]. / Schwere kalzifizierende Atherosklerose der thorakalen Aorta mit Symptomen einer Aortenisthmusstenose. Fallbeschreibung.

Calcifying obliterative atherosclerosis isolated within the descending thoracic aorta causing subtotal vascular occlusion was associated with symptoms such as in aortic coarctation in a 56-year-old patient. Remarkable in this unique case is the atypical and isolated manifestation of atherosclerotic disease within the thoracic aorta, as well as the tumorous extent of luminal calcification. Differential diagnostic considerations had to include calcifying tumor of the aorta, remnants after aortitis or secondary calcified aortic dissection.