Portal vein stenting the first day after orthotopic liver transplantation for residual postthrombotic stenosis compromising portal flow.

BACKGROUND: Early portal vein impairment or thrombosis after liver transplantation is a significant risk factor for graft failure. CASE: Here, we describe a case of severe portal hypoperfusion after thrombectomy during liver transplantation that was treated with percutaneous stenting on the first postoperative day. Stenting was combined with embolization of varices and normalized portal inflow. RESULT: Liver function and portal flow were normal after 1 year of follow-up. CONCLUSION: This case demonstrates that percutaneous stenting is a safe and feasible therapeutic option even in the initial days after liver transplantation.

Aptamer-based isolation and subsequent imaging of mesenchymal stem cells in ischemic myocard by magnetic resonance imaging.

PURPOSE: Mesenchymal stem cells (MSC) seem to be a promising cell source for cellular cardiomyoplasty. We recently developed a new aptamer-based specific selection of MSC to provide "ready to transplant" cells directly after isolation. We evaluated MRI tracking of newly isolated and freshly transplanted MSC in the heart using one short ex vivo selection step combining specific aptamer-based isolation and labeling of the cells. MATERIALS AND METHODS: Bone marrow (BM) was collected from healthy pigs. The animals were euthanized and the heart was placed in a perfusion model. During cold ischemia, immunomagnetic isolation of MSC from the BM by MSC-specific aptamers labeled with Dynabeads was performed within 2 h. For histological identification the cells were additionally stained with PKH26. Approx. 3 x 10(6) of the freshly aptamer-isolated cells were injected into the ramus interventricularis anterior (RIVA) and 5 x 10(5) cells were injected directly into myocardial tissue after damaging the respective area by freezing (cryo-scar). 3 x 10(6) of the aptamer-isolated cells were kept for further characterization (FACS and differentiation assays). 20 h after cell transplantation, MRI of the heart using a clinical 3.0 Tesla whole body scanner (Magnetom Trio, Siemens, Germany) was performed followed by histological examinations. RESULTS: The average yield of sorted cells from 120 ml BM was 7 x 10(6) cells. The cells were cultured and showed MSC-like properties. MRI showed reproducible artifacts within the RIVA-perfusion area and the cryo-scar with surprisingly excellent quality. The histological examination of the biopsies showed PKH26-positive cells within the areas which were positive in the MRI in contrast to the control biopsies. CONCLUSION: Immunomagnetic separation of MSC by specific aptamers linked to magnetic particles is feasible, effective and combines a specific separation and labeling technique to a "one stop shop" strategy.

[Interventional MR imaging in musculoskeletal]. / La Résonance Magnétique Interventionnelle en pathologie ostéoarticulaire.

Magnetic resonance (MR) imaging is well established for the diagnosis of musculoskeletal diseases. The excellent tissue contrast and the multiplanar imaging capability have both contributed to the improvement of this technique. The development of fast acquisition techniques, sufficient patient access obtained with open magnet configurations and advances in the technology of MR compatible instruments allow a new approach to interventional radiology. These recently commercially available open-bored high-field magnets allow standard interventions such as biopsies or intra-articular infiltrations. Moreover, new interventions e.g. preoperative marking of soft tissue or bone marrow tumors are now possible with the better tissue contrast of MR imaging.

Differentiation between malignant and benign solitary pulmonary nodules with proton density weighted and ECG-gated magnetic resonance imaging.

OBJECTIVE: To estimate performance of MRI for differentiating malignant from benign solitary pulmonary nodules (SPN) using morphological characteristics. MATERIAL AND METHODS: MRI in 46 patients with SPN (mean diameter: 19 mm) was carried out on 1.0 Tesla scanner using ECG-gated, gradient echo sequence. Morphological signs of SPN were determined and compared with previously performed helical-CT, where final diagnosis served as reference with 52% frequency of malignancy. Furthermore, three observers evaluated all images. RESULTS: Significant differences between the two groups were found for nodules shape, margin, inhomogeneity and the vessel-sign in MRI, nodules shape, margin, the vessel-sign, and presence of spicules in CT. Using these signs, AUC were 0.746 for MRI and 0.765 for CT. The mean sensitivity, specificity, and accuracy of observers for MRI/CT were 89%/95%, 42%/41%, 66%/68%, respectively. CONCLUSIONS: Despite discrepancies in morphologic appearance, no significant difference of accuracy between MRI and CT was determined. Further investigations are necessary to demonstrate the clinical use in combination with functional parameters, establishing MRI as a comprehensive diagnostic modality for SPN.

Percutaneous vascular interventions in the superficial femoral artery. A review.

The superficial femoral artery (SFA) is a frequent target of atherosclerotic disease predominantly in the proximal section near the bifurcation to the deep femoral artery and in the distal section where the adductor muscles tend to compress the artery. In the past, SFA revascularization was the domain of vascular surgery (femoropopliteal and femorodistal bypasses). However, with the development of endovascular treatment and advancing techniques as well as more sophisticated stenting material and balloons, endovascular treatment is nowadays not just a treatment option but, in most cases, preferable at least as initial revascularization procedure in the treatment of peripheral artery vascular disease. In the last years, many efforts have been made to fight restenosis in revascularized artery segments after stenting and/or angioplasty. This article aims to give a review on this topic including the most recent experience with the various latest revascularization techniques such as drug eluting stents, coated stent grafts, brachytherapy, cryoplasty, cutting balloons, and drug coated balloons.

[A preparation technique for quantitative investigation of SPIO-containing solutions and SPIO-labelled cells by MRI]. / Eine Präparationstechnik zur quantitativen Untersuchung SPIO-haltiger Lösungen und SPIO-markierter Zellen in der MRT.

UNLABELLED: PURPOSE. This work aims to present a preparation technique for ex-vivo MR examination of SPIO (superparamagnetic iron oxide) containing solutions or SPIO labeled cells. Accumulations of SPIO particles and labeled cells were prepared in different concentrations using agar gel phantoms. Signal extinction around accumulations of magnetic material was examined systematically by gradient echo sequences with variable echo times and spatial resolution. The correlation between local iron concentration and diameter of signal extinction in MR gradient echo images was investigated. METHODS: Resovist, (SHU 555A) was used as superparamagnetic contrast medium. Different concentrations of SPIO-containing solutions (0.75 - 15 mg Fe/10 ml) and magnetically labeled SK-Mel28 cells (25,000-1,000,000 cells/10 ml) were accommodated inside a defined volume in an agar matrix. Diameters of signal void were assessed in dependence on local iron concentration, echo time (5-25 ms) and isotropic spatial resolution (length of voxel 0.25 - 0.60 mm). Measurements were performed on a clinical MR whole body scanner (3 Tesla) using a spoiled gradient echo sequence (FLASH). RESULTS: For the present experimental conditions sensitivity to detect the magnetic label was maximized using TE 25 ms. In contrast, the area of signal cancellation was minimized using TE 5 ms and isotropic resolution of 0.25 mm. In the latter case the image indicated the area of magnetic material most precisely. Diameter of signal cancellation was a logarithmic function on local iron concentration. In the presented set-up detection of concentrations as low as 0.75 mg Fe/10 ml in SPIO-containing solution or 1.25 mg Fe/10 ml in SPIO-labeled SK-Mel28 cells was certainly possible. CONCLUSION: The proposed preparation strategy with a well defined spatial distribution of the magnetic material in an agar gel phantom produced reliable results and appears clearly superior compared to set-ups with randomly distributed material in glass tubes. The diameter of the signal extinction in gradient echo images was significantly affected by the choice of echo time and spatial resolution. The calibration of signal cancellation versus iron concentrations may be valuable to assess SPIO concentrations and possibly numbers of labeled cells under specific conditions in vitro or even in vivo.

Rhenium-188 for inhibition of human aortic smooth muscle cell proliferation.

PURPOSE: To evaluate dose-dependent growth-modulating effects of the beta-gamma emitter Rhenium-188 on cultured human aortic smooth muscle cells (haSMC). METHODS AND MATERIALS: HaSMC were plated in 25 cm(2) flasks. Two days after plating, cells were incubated with the Re-188 (beta E(max) 2.12 MeV, tissue range(max) < 10 mm, T(1/2) 17 h) for five days. The doses administered were 0.2 Gy, 1, 4, 6, 8, 16, and 32 Gy. After five days, the radionuclide was removed. Cell growth, cell cycle distribution, and clonogenic activity were analyzed for the following 25 days. RESULTS: The 0.2 and 1 Gy groups did not show relevant growth-inhibiting effects compared to the control groups. The 4 to 32 Gy groups presented dose-dependent growth inhibition, with a complete growth arrest of the 16 and 32 Gy groups. Clonogenic activity of the smooth muscle cell was strongly inhibited from doses > or =8 Gy. Flow cytometry showed a lasting dose-dependent G2/M phase block. CONCLUSION: Smooth muscle cell (SMC) growth can be controlled effectively with Re-188 for at least 25 days after radiation in vitro. As the first four weeks after arterial angioplasty are crucial concerning neointimal formation, Re-188 may be a valuable radionuclide to inhibit restenosis after arterial angioplasty.

Dynamic changes of the spinal canal in patients with cervical spondylosis at flexion and extension using magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The authors determine the dynamic changes of the spinal canal during flexion and extension in patients with cervical spondylosis. METHODS: Forty-six patients were studied inside a whole-body magnetic resonance (MR) scanner with between 50 degrees of flexion and 30 degrees of extension, using a positioning device. At neutral position (0 degree) and maximum flexion and extension sagittal T2-weighted turbo spin echo sequences were acquired. RESULTS: A significant (P < or = 0.05) increase of spinal stenosis was found at extension (48%, 22 of 46 patients) when compared with flexion (24%, 11 of 46). Cervical cord compression was diagnosed at flexion in 5 patients (11%) and at extension in 9 patients (20%). Concerning the number of patients with cervical cord compression at flexion and extension, significant differences (P < or = 0.05) were found in patients with degenerative changes at four segments compared with patients with one segment involvement. CONCLUSIONS: Magnetic resonance imaging identified a significant percentage of increased spinal stenosis at flexion and, especially, at extension, which was not observed at neutral position (0 degree). Flexion and extension MR imaging demonstrates additional information using a noninvasive technique concerning the dynamic factors in the pathogenesis of cervical spondylotic myelopathy.

Biomechanical aspects of the subarachnoid space and cervical cord in healthy individuals examined with kinematic magnetic resonance imaging.

STUDY DESIGN: In vivo flexion-extension magnetic resonance imaging studies of the cervical spine were performed inside a positioning device. OBJECTIVE: To determine the functional changes of the cervical cord and the subarachnoid space that occur during flexion and extension of the cervical spine in healthy individuals. SUMMARY OF BACKGROUND DATA: As an addition to static magnetic resonance imaging examinations, kinematic magnetic resonance imaging studies of the cervical spine were performed to obtain detailed information about functional aspects of the cervical cord and the subarachnoid space. The results were compared with published data of functional flexion-extension myelograms of the cervical spine. METHODS: The cervical spines of 40 healthy individuals were examined in a whole-body magnetic resonance scanner from 50 degrees of flexion to 30 degrees of extension, using a positioning device. At nine different angle positions, sagittal T1-weighted spin-echo sequences were obtained. The images were analyzed with respect to the segmental motion, the diameter of the subarachnoid space, and the diameter of the cervical cord. RESULTS: The segmental motion between flexion and extension was 11 degrees at C2-C3, 12 degrees at C3-C4, 15 degrees at C4-C5, 19 degrees at C5-C6, and 20 degrees at C6-C7. At flexion, a narrowing of the ventral subarachnoid space of up to 43% and a widening of the dorsal subarachnoid space of up to 89% (compared with the neutral position, 0 degrees) were observed. At extension, an increase in the diameter of the ventral subarachnoid space of up to 9% was observed, whereas the dorsal subarachnoid space was reduced to 17%. At flexion, there was a reduction in the sagittal diameter of the cervical cord of up to 14%, and, at extension, there was an increase of up to 15%, compared with the neutral position (0 degrees; these values varied depending on the cervical segment. Statistically significant differences (P < 0.05) were found between flexion and extension in the diameter of the ventral and dorsal subarachnoid space and in the diameter of the cervical cord. CONCLUSIONS: Compared with the results of previous studies using functional cervical myelograms, kinematic magnetic resonance imaging provides additional noninvasive data concerning the physiologic changes of the cervical subarachnoid space and the cervical cord during flexion and extension in healthy individuals.

[Kinematic MRI in degenerative cervical spine changes]. / Kinematische MRT bei degenerativen Halswirbelsäulenveränderungen.

AIM: To evaluate functional stenosis of the cervical spine, kinematic MRI was performed in 23 healthy volunteers and 23 patients with degenerative disease. MATERIAL AND METHOD: Kinematic MRI of the cervical spine was done from 50 degrees of inclination to 30 degrees of reclination. Depending on the maximum inclination and reclination the range of motion was divided into 9 equal angle positions. At each angle position sagittal T2* weighted gradient echo sequences were performed. RESULTS: In relation to the neutral position a physiological narrowing of the ventral epidural space was seen in healthy volunteers at inclination (50 degrees) in up to 50% and respectively widening at reclination (30 degrees) in up to 10%. An increase of spinal canal stenosis or even spinal cord compression was seen at inclination in 5 patients (22%) and in 15 patients (65%) at reclination. No change of spinal canal stenosis was found in three patients (13%). CONCLUSION: In patients with degenerative disease of the cervical spine kinematic MRI demonstrated in some patients functional spinal canal stenosis with myelon compression which was not seen in standard MRI. Therefore kinematic MR imaging can be recommended as a complementary examination in the early detection of functional myelon compression and in planning the further therapeutic work-up.

[Dose dependent effects of the combined beta-gamma-emitter 188Rhenium on the growth of human vessel wall cells]. / Dosisabhängige Auswirkungen des kombinierten beta-gamma-Emitters 188Rhenium auf humane Endothelzellen und humane vaskuläre glatte Muskelzellen.

PURPOSE: To evaluate the dose of (188)Re that completely suppresses growth and clonogenic activity of human aortic smooth muscle cells (haSMC) since these cells are mainly responsible for restenosis occurring after PTA. For comparison, growth and clonogenic activity of endothelial cells (EC) were investigated with corresponding doses. MATERIALS AND METHODS: Two days after plating, haSMC and EC were incubated with (188)Re for five days. The doses applied ranged from 4 to 16 Gy. Cell growth was observed for a period of 20 days (EC) or 30 days (haSMC), respectively. Clonogenic activity was monitored over a period of 20 days for both cell lines. RESULTS: Irradiation caused dose-depend-ent inhibition of cell growth and clonogenic activity both in haSMC and in EC. HaSMC growth was completely blocked with 8 Gy, while EC still showed some proliferation even with 16 Gy. The clonal activity of haSMC was also completely blocked with 8 Gy while EC still showed little clonal activity even with 16 Gy. CONCLUSION: Cell growth of both haSMC and EC can be effectively suppressed in a dose-dependent manner. Only haSMC showed a complete growth arrest with 8 Gy while EC were able to proliferate even with 16 Gy. HaSMC colony formation was completely suppressed after application of 8 Gy, while the EC still showed colony formation activity with 16 Gy. (188)Re has some advantageous properties for intravascular irradiation in comparison to other radionuclides making it an interesting radionuclide for stent coating to prevent restenosis.

[MR-venography using manual flow augmentation in an open low field MR system]. / MR-Venographie am offenen Niederfeldtomographen unter Verwendung manueller Flussaugmentation.

OBJECTIVE: To evaluate the feasibility of signal enhancement in the deep veins by means of manual compression of the calf (flow augmentation) as a new approach to MR venography in open configuration, low-field systems. METHODS: 10 healthy volunteers underwent MR venography of the calf unconstrained and during short localized manual compression. Gradient recalled echo sequences (FLASH, FISP) with repeated single slice acquisition and first-order gradient motion refocussing were tested in four protocols with and without arterial presaturation slabs (scan time 2.2 - 5.0 s per slice). The effect on flow enhancement was rated by means of a signal score. Interventional accessories, particularly an in-room LCD screen, were required for interactive application of compression manoeuvres. RESULTS: Sequences with arterial presaturation slabs were superior to those without regardless of the longer acquisition times. Careful targeting of compression to the mid-time of data acquisition was crucial to obtain marked flow acceleration. Enhancement was best in the case of proximally applied calf compression. Signal improvement was consistently achieved in the proximal parts of the posterior tibial and peroneal veins, but was only seen in 4/10 volunteers in the distal part of the anterior tibial vein. CONCLUSION: Flow augmentation by means of manual calf compression is a simple and effective complementary approach to MR venography in open configuration, low field MR systems.

[Direct CT-arthrography versus direct MR-arthrography in chronic shoulder instability: comparison of modalities after the introduction of multidetector-CT technology]. / Direkte CT-Arthrographie versus direkte MR-Arthrographie bei chronischer Schulterinstabilität: Ein Methodenvergleich nach Einführung der Multidetektor-CT-Technik.

PURPOSE: To evaluate the diagnostic accuracy of direct multidetector CT arthrography (CTA) and direct MR arthrography (MRA) in patients suffering from chronic shoulder instability. MATERIALS AND METHODS: Twenty-nine patients suffering from chronic shoulder instability were included into a prospective study. In all cases, the indication for direct CTA and arthroscopy was set by the orthopedic surgeon. Prior to the imaging procedures, 10 to 20 ml of a special combination of contrast media (including saline, Isovist(R) and Magnevist(R) in a relation of 125 : 125 : 1) was injected into the joint under sterile conditions. First, CTA was performed with a multidetector CT, with images reconstructed in the axial, semi-coronal and semi-sagittal planes. Thereafter, MRA was performed. Axial images were obtained using a T1-weighted, fat-saturated spin echo sequence and semi-coronal images using a T1-weighted FLASH-3D GRE sequence. The results of CTA and MTA were compared with results obtained from arthroscopy or arthrotomy. RESULTS: MRA was superior to CTA in the detection of labral lesions. The sensitivity of MRA was 96 % and the specificity 96 %, compared to a sensitivity of 76 % (p < 0.05) and specificity of 92 % for CTA. Both methods showed the same effectiveness concerning the assessment of capsule distension (sensitivity for both techniques: 91 %). CONCLUSIONS: MRA seems to be superior to CTA in the diagnostic workup of chronic shoulder instability even when using a multidetector CT technique.

Radiopaque markers in endovascular stents--benefit and potential hazards.

AIM: The primary objective of this study was to evaluate the impact of radiopaque markers on stent visibility. The secondary objective was to investigate the impact of such radiopaque markers on localized corrosion at the stent corpus-marker interfaces. MATERIAL AND METHODS: The radiopacity of the following stents was evaluated at different fluoroscopy modes (spotfilm, continuous fluoroscopy, 15 p/s, 7.5 p/s, 3 p/s): Memotherm Flexx (FX), Memotherm Luminexx (LX)(Bard), SMART (SM), SMARTeR (SMR)(Cordis). Four readers evaluated a total of 3200 images (160 per stent per fluoro mode) according to the following radiopacity score (RS): 0 = no stent visible, 1 = poor, 2 = acceptable, 3 = good, and 4 = very good stent visibility. LX and SMR stents (n = 5/group) were subjected to potentiodynamic polarization testing in de-aerated Hanks salt solution at 37 degrees C using a potentiostat. Palmaz-Schatz stents (n = 3) were used as the control group for comparative evaluation. The corrosion current density (I corr ) and the breakdown value (E bd ) were compared parameters of interest. RESULTS: At the spotfilm mode the LX, the SM and the SMR were rated well to very well visible in 99 %, 96 %, 96 %, and the FX only in 64 %. At 7.5 p/s (standard fluoro mode) the LX was considered to be well to very well visible in 77 %, followed by the SMR in 12.5 %, the SM in 1 %, and the FX in 0 %. The SMR stents exhibited the highest E bd values (802 +/- 112 mV vs SCE), while the LX stents exhibited the lowest E bd values (155 +/- 38 mV vs SCE). Also, the average E bd values for the SMR stents were better than those exhibited by the PS stents (503 +/- 107 mV vs SCE). CONCLUSION: Stent radiopacity can be increased significantly with the help of radiopaque markers (p < 0,0001 LX vs. FX). However, the surface condition of the stent corpus and the mode of attachment of the marker onto the corpus may have a significant impact on the uniformity of the final corrosion behavior. It is not feasible to determine the clinical impact of this localized corrosion behavior from this in vitro study. Further experimentation is recommended to ascertain the same.

[Liposome-mediated transfection of thrombomodulin in vascular smooth muscle cells--a gene therapy concept to inhibit recurrent stenosis]. / Liposomal vermittelte Transfektion von Thrombomodulin in vaskuläre glatte Muskelzellen - ein Gentherapie-Konzept zur Inhibition der Rezidiv-Stenose?

PURPOSE: Thrombomodulin (TM), an integral endothelial receptor, is known for its anticoagulant functions. Moreover, there is evidence of growth-modulating effects of this cell surface -protein. The aim of our study was to establish by in vitro transfection a stable cell line of vascular smooth muscle cells with overexpression of TM for further investigations concerning the influence of TM on cellular proliferation and its potential role during the formation of restenosis. METHODS: Aortic smooth muscle cells of the rat were transfected with cDNA of mouse TM or one of its three mutants (M1, M2, M4) by a liposome-mediated technique. The expression of mouse TM mRNA in the selected clones was proven with the help of RT-PCR. Changes of cell proliferation were determined by proliferation kinetics over 24 days. The quantification of the total protein TM was made by Western blots. RESULTS: In 44 of 100 cases the RT-PCR confirmed a successful transfection of mouse-TM. The clones with transfected TM, M1 or M2 showed an inhibited cell growth, whereas M4 demonstrated an increased proliferation compared with controls. The comparison of amounts of total TM with cell growth of individual clones resulted in a negative correlation between proliferation and TM-expression (coefficient of correlation for TM -0.87, for M1 -0.59). CONCLUSIONS: It is possible to reproduce stable cell-lines of vascular smooth muscle cells with overexpression of TM by the presented model of in vitro transfection. Thus, a basis exists for detailed examinations of growth-regulating mechanisms by TM.

[Possibilities of the prophylaxis of arterial restenoses with dexamethasone -- an in-vitro study of human aortic smooth muscle cells]. / Möglichkeiten der Prophylaxe von arteriellen Restenosen mit Dexamethason -- eine In-vitro-Studie an humanen aortalen glatten Muskelzellen.

PURPOSE: To evaluate the effect of dexamethasone on the growth of cultured human aortic smooth muscle cells in an in-vitro model depending on the dose applied. MATERIALS AND METHODS: Commercially available human aortic smooth muscle cells (haSMC) were incubated with different doses of dexamethasone (10(-6), 10(-8), 10(-10) mol/l). For 20 days, the dose-depending effects of dexamethasone on cell growth were studied by analyzing cell proliferation, clonogenic activity as well as cell cycle distribution. In addition, the migratory ability of haSMC was evaluated using a two compartment in-vitro model. RESULTS: Cell growth was reduced in a dose dependent manner. An applied dose of 10(-6) M dexamethasone effectively inhibited cell growth for the follow-up period of 20 days. Cell cycle analysis revealed a G1-phase block which was dose dependent and significant for a dose of 10(-6) M. Also a reduction of haSMC clonogenic activity could be found in the colony formation assays. Finally, dexamethasone reduced the migratory ability of the treated cells significantly for doses of 10(-6) and 10(-8) M. CONCLUSION: Depending on the dose applied, incubation with dexamethasone results in a significant growth reduction of cultured haSMC, which may be due to a drug induced G1-phase block. Dexamethasone also reduces the clonogenic activity as well as the migratory ability of cultured haSMC.

[Dose-dependent effects of the combined beta/gamma emitter 186-Rhenium on the growth of human vessel wall cells]. / Dosisabhängige Auswirkungen des kombinierten beta/gamma Emitters Rhenium186 auf das Wachstum humaner Gefässwandzellen.

PURPOSE: The aim of this study was to evaluate the capability of human aortic smooth musc e cells (HaSMC) and endothelial cells (EC) to recover after incubation with the combined beta/gamma emitter 186rhenium. MATERIALS AND METHODS: Two days after plating, HaSMC and EC were incubated for five days with 186Re (total doses applied 4 Gy-32 Gy). Cell counts were performed for a period of 30 days (haSMC) and 22 days (EC). To detect possible growth recovery, colony formation assays were plated for both cell types on day 5, 10, and 20 (and lay 30 for haSMC). RESULTS: Both cell types presented a dose-dependent growth inhibition which was maximum at a dose of 32 Gy. Human endothelial cells presented with total growth recovery at 4 and 8 Gy, and a partial growth recovery at 16 Gy. Smooth muscle cells only presented partial growth recovery at 4 and 8 Gy. At 16 Gy and more no recovery was detected. CONCLUSION: HaSMC as well as EC growth can be modulated effectively with 186Re over a period of 30 days in vitro. Compared to smooth muscle cells human endothelial cellls seem to possess a higher potential to recover at doses of 8 to 16 Gy. 186Re may be a valuable radionuclide to prevent restenosis.

A new device for percutaneous suture-mediated closure of arterial puncture sites using exteriorized needles: initial experience.

PURPOSE: To assess the feasibility and initial clinical results of Closer (Perclose, Redwood City, California), a new device for percutaneous suture-mediated closure of arterial puncture sites. METHODS: Vascular interventions were performed using 6 and 7 French sheaths in 22 consecutive patients. All patients underwent suture-mediated percutaneous closure with the new device. Patients were followed by physical examination the day after the procedure. RESULTS: Immediate hemostasis was achieved in 20/22 patients (91%). In 3 out of 5 antegrade closures, only one suture was captured. In two cases, this was managed by reinsertion of a second device. In another patient, hemostasis was not achieved by the device due to knot entrapment. No major complications were observed. The overall rate of minor complications was 9% (2/22) due to hematomas without the need for blood transfusions. CONCLUSION: Percutaneous suture with this new device is an acceptably safe and effective method to achieve immediate hemostasis of the arterial access site after interventional procedures with minimized manipulation of the puncture track.

Difference in dose area product between analog image intensifier and digital flat panel detector in peripheral angiography and the effect of BMI.

PURPOSE: Comparison of dose area products (DAP) in diagnostic angiography procedures between an image intensifier (II) and a flat panel detector (FPD) angiography system and the evaluation of DAP/body mass index (BMI) dependency. MATERIALS AND METHODS: An image intensifier system or a flat panel detector system was used to perform 571 diagnostic angiographies (n = 328 and n = 243, respectively) of 5 different types: peripheral arterial, venous, single leg, abdominal and upper extremity. The results were retrospectively analyzed. The DAP, fluoroscopy time (t) and the number of series of the respective interventions as calculated by the respective machines was compared for all interventions and for the respective subtypes and machines. The BMI dependency was calculated separately for both machines for all interventions by subdividing the patients into 6 BMI classes defined by the WHO. RESULTS: The average DAP for all diagnostic interventions was 1958.9 cGy×cm2 (t = 384.6 s, n = 7.85 series) for the II and 2927.4 cGy×cm2 (t = 267.4 s, n = 7.02 series) for the FPD. Group-dependent differences ranged between + 21 and + 252 % when using the FPD system. After time standardization, the respective increases were found to be 120 % for the FPD system. The DAPs increased considerably in patients with higher BMIs (766.7 cGy × cm2 - 6892.6 cGy × cm2, II machine, 950.5 cGy × cm2 - 12 487.7 cGy × cm2, FPD machine) with a greater DAP gain seen for the FPD. The average duration of the interventions was higher using the II machine. CONCLUSION: The use of an FPD system led to higher DAP values compared to the II system in diagnostic angiographic procedures. In addition, increased BMI values led to higher DAPs, especially for the FPD machine. However, the average fluoroscopy times were shorter.