Claudius König

Frequent embolization in peripheral angioplasty: detection with an embolism protection device (AngioGuard) and electron microscopy.

AbstractPurpose: To evaluate the deliverability and protection capabilities of an embolism protection filter in angioplasty of peripheral arteries. Methods: The Angioguard emboli capture guidewire system was applied in 11 patients with femoropopliteal lesions (6 stenoses, 3 occlusions, 2 controls). Data on lesion crossing, flow deceleration and macroembolization were recorded. Filter membranes were evaluated with scanning electron microscopy (SEM). Results: System delivery was successful in all patients. Primary lesion crossing was feasible in four of six stenoses; predilatation was required in two of six. Marked flow deceleration was recorded in six patients. Emboli next to the filter were detected in each patient with concentric plaques, but could not reliably be removed with the filter. Downstream macroembolization was also present in all patients with concentric stenoses, but in none with chronic occlusion. None of the patients had clinical signs of ischemia. SEM analysis demonstrated only small particles on control group filters and non-obliterating fibrinous conglomerates on filters used in chronic occlusion. Substantial obliteration was seen on several filters used in stenotic lesions. Conclusion: Microembolization of fibrin aggregates is a common incident in balloon angioplasty of femoropopliteal stenoses. Macroembolization occurred more frequently than previously reported. The use of embolism protection filters aided in the detection but not in the removal of larger emboli.

Real-time MR fluoroscopy-navigated lumbar facet joint injections: feasibility and technical properties.

We prospectively evaluated the feasibility and technical properties of a dedicated interventional magnetic resonance (MR) imaging protocol for near-real-time MR fluoroscopy-guided bilateral lumbar facet joint injections. A total of 44 facet joint injections were performed in 22 patients using a C-shaped open 0.2-T MR imaging system (Magnetom Concerto, Siemens Medical Solutions, Erlangen, Germany). A T1/T2*-weighted fast-imaging-with-steady-precession (FISP) sequence with an end-to-end latency of 1.2 s facilitated sufficient near real-time MR imaging guidance in all cases. A T1-weighted two dimensional fast-low-angle-shot (FLASH2D) MR sequence identified final needle tip location. Different angles of the needle path had only minimal influence on the appearance of the needle artifact produced by both sequences, resulting in a symmetrical needle tip artifact. The joint cavity was successfully punctured in 79.5% (35/44) of joints, which was followed by intra-articular fluid accumulation in 75% (33/44). Inaccessible joints demonstrated a significantly (p=0.044) higher number of posterior osteophytes (66.7%, 6/9 joints) compared to accessible joints (26%, 9/35 joints). No complications occurred. Table time showed significant shortening over time with average table time of 33 (21–68.5) min. We conclude that MR fluoroscopy-navigated lumbar facet joint injections are feasible and safe.

Xanthogranulomatous cholecystitis resembling carcinoma with extensive tumorous infiltration of the liver and colon

BackgroundXanthogranulomatous cholecystitis is a macrophage-rich inflammatory condition of the gallbladder that occasionally presents with tumorlike appearance.Case presentationIn the present case the inflammation involved all the layers of the gallbladder, the surrounding connective tissue, and part of the right lobe of the liver and right transverse colon. The clinical and radiological findings were suggestive of advanced carcinoma of the gallbladder. However, intraoperative frozen section investigation revealed xanthogranulomatous cholecystitis, for which simple cholecystectomy is the treatment of choice.ConclusionsThe original cause of the condition is unclear in most cases. In the present case it is possible that rupture of the gallbladder in association with the patients known history of trauma have initiated the process

Technical report and preliminary clinical data of a novel catheter for luminal re-entry after subintimal dissection.

Rationale and Objectives:The objective of this study was to evaluate the safety and the effectiveness of the Outback catheter for intraluminal re-entry after subintimal dissection in the crossing of chronic arterial occlusions. Methods:This study was a proof-of-concept feasibility. Ten patients with totally occluded arteries in the iliac artery to the distal femoral artery (mean occlusion length, 13.1 cm; range, 5–25 cm) were treated with the novel catheter. After successful re-entry, PTA or PTA plus stenting was performed. Results:No perforations, dissections, lacerations, or device complications occurred. The procedural re-entry success rate with the Outback catheter was 50% (5/10 patients). Conclusions:Although the Outback catheter is safe, the percentage of intraluminal reaccess should be ameliorated through engineering improvements because there is some evidence to suggest that subintimal recanalization could produce improved long-term results.

[MRI-guided percutaneous radiofrequency ablation of hepatic neoplasms--first technical and clinical experiences].

Purpose: To evaluate the safety and efficacy of MR-guided radiofrequency ablation (RFA) of hepatic neoplasms. Material and Methods: 16 hepatic neoplasms (1.3-3.0 cm in diameter) in 11 patients were treated by 22 percutaneous RFA sessions during a prospective study. 16 G, MR-compatible cooled-tip electrodes with active lengths of 2 cm and 3 cm, respectively, were placed under MR-guidance in an open 0.2 Tesla MR system (Magnetom Open, Siemens, Erlangen) using fast T 1 -weighted sequences. Pretreatment studies, evaluation of tumor necrosis (one week after last RFA), and further follow-up studies every 3 months were performed using 1.5 Tesla MR systems. Results: The mean procedure time was 2.8 (1.5-3.3)h. Complications related to percutaneous treatment were not encountered. 14 of 16 neoplasms (87%) showed no CM enhancement during MRI after the last RFA and were judged to be completely necrotic. In 11 tumors one treatment session was necessary, in 4 tumors two and in one tumor three. Follow-up studies revealed persistent complete necrosis in 13 of 14 (93%) tumors during a period of 3 - 18 (median: 11.8) months. In 5 patients new intrahepatic tumors developed that were not suitable for further RFA treatment because of their number, size and location, conclusion: MR-guided RFA using single cooled tip electrodes is safe and technically effective for treatment of hepatic neoplasms up to 3 cm in size, however further improvements are necessary.

Contrast enhanced MR-guided biopsy of hepatocellular carcinoma.

Magnetic resonance (MR)–guided liver biopsy was performed in three patients with hepatocellular carcinoma. The tumor was considered (n = 2) or proven (n = 1) inaccessible with ultrasound or computed tomographic guidance. Because all lesions were poorly delineated on nonenhanced MR imaging, contrast agents (Gd-BOPTA, n = 1; ferucarbotran, n = 2) were applied to facilitate biopsy in an open low-field scanner. Postcontrast tumor conspicuity was fair in the patient receiving Gd-BOPTA and excellent in both patients receiving ferucarbotran, and biopsy was successful in all cases.

Magnetic resonance-guided transcortical biopsy of bone marrow lesions using a magnetic resonance imaging-compatible piezoelectric power drill: preliminary experience.

König CW, Trübenbach J, Böhm P, et al. Magnetic resonance-guided transcortical biopsy of bone marrow lesions using a magnetic resonance imaging-compatible piezoelectric power drill: Preliminary experience. Invest Radiol 2003;38:159–163. Rationale and Objectives. To test utility and specific properties of a commercially available MRI compatible power drill for MR guided transcortical bone biopsy. Methods. In 17 patients MR-guided bone biopsy was performed in an open low-field scanner (0.2 T), using a piezoelectrically powered drilling machine. Target lesions were osteoblastic in four and nonsclerosed intramedullary in 13 cases. Titanium drills sized 3 to 4 mm and an outer cannula were coaxially used for power assisted cortical trephination. For intramedullary lesion sampling, spring loaded biopsy guns and sharpened cannulas were additionally applied in seven and fluid aspiration in two patients, respectively. Results. The piezoelectric device proved to be fully MR compatible. Trephination and subsequent biopsy was successful in all patients without major complications. The drilling procedure could entirely be performed inside the magnet in case of a lateral approach (n = 11). The net drilling time averaged 7.8 minutes for trephination of nonimpaired diaphyseal bone, but was up to 50 minutes in case of thickened femoral bone. Procedures were complicated by frequent drill loosening, drill obstruction by cortical bone (n = 4) and impaired periosteal grip (n = 5) with damage to the outer cannula (n = 3). Conclusions. The piezoelectric power drill can be applied safely in a low-field MRI environment and is a valuable tool to facilitate transcortical bone biopsy.

[CT-guided radiofrequency (RF) ablation of osteoid osteoma: clinical long-term results].

PURPOSE To evaluate CT-guided radiofrequency (RF) ablation of osteoid osteoma using internally cooled monopolar RF electrodes for technical success, complications and clinical long-term success. MATERIALS AND METHODS Between April 1999 and July 2006, 23 patients were treated under general anesthesia with CT-guided RF ablation using an internally cooled monopolar single RF electrode (Cool-tip, Valleylab, TycoHealthcare, Boulder, USA; active tip: 10 mm). For the removal of the nidus, we used either a manual or an automated drill. The technical success was evaluated by a CT scan (MSCT, Siemens Medical Solutions, Forchheim). The clinical long-term success was investigated by questioning patients prior to discharge, and after 6, 12 and 18 months. After 18 months, patients were interviewed on an annual basis. RESULTS The technical success rate was 100 %. The nidus was located in n = 19 cases at the lower extremity and in n = 4 cases at the upper extremity. Minor complications were observed for n = 2 patients. The mean hospitalization time was 1.5 d (1-2 d). The mean follow-up was 75.9 months (18-120 months) for n = 23 patients. No local recurrence was observed. One patient had intermediate pain one week after RF ablation without recurrent symptoms. CONCLUSION CT-guided RF ablation using an internally cooled monopolar single RF electrode is an effective and safe minimally invasive method for the treatment of osteoid osteoma with excellent clinical long-term success.

Percutaneous MR-Guided Radiofrequency Ablation of Recurrent Sacrococcygeal Chordomas

OBJECTIVE Radiofrequency ablation is emerging as a therapeutic technique for the treatment of an increasing variety of tumors. Exact visual guidance to the tumor and controlled delivery of energy is pivotal for ablation success. CONCLUSION Introducing MRI as a guidance technique ideally uses tumor-specific tissue characteristics, allows direct multiplanar reconstruction for precise needle positioning, and permits real-time monitoring and assessment of treatment-induced tissue signal changes to increase the safety of the procedure.

Technik und Ergebnisse der CT-gesteuerten perkutanen Knochenbiopsie

ZusammenfassungZielsetzung. Ziel dieser Studie war es, die Möglichkeiten und Ergebnisse der CT-gesteuerten perkutanen Knochenbiopsie (PKB) unklarer Knochenläsionen an einem repräsentativen Krankengut zu überprüfen. Methoden. Bei 92 Patienten (100 Biopsien) mit verschiedenen Knochenerkrankungen wurde der Wert der PKB untersucht. Ergebnisse. Es ergab sich ein technischer Erfolg, definiert als erfolgreiche Probeentnahme, bei der Material für eine histologische Evaluation zur Auswertung gelangte, von 89% (89/100 Biopsien) und eine diagnostische Treffsicherheit, definiert als klinisch verwertbares histologisches Ergebnis, von 80% (80/100 Biopsien). Bei 3% der Punktionen wurden nicht therapierelevante Komplikationen (geringfügige Blutungen) gesehen. Osteolytische Läsionen waren mittels PKB besser einzuordnen (92%) als osteoplastische (80%) oder gemischtförmige Läsionen (67%). Betrachtet man die der PKB zugrundeliegende vermutete Ätiologie der Läsion, so weisen auf Malignität verdächtige Läsionen mit im Durchschnitt 82% Genauigkeit gegenüber 50% bei Verdacht auf benigne Knochenläsion eine deutlich bessere diagnostische Quote auf. Schlussfolgerungen. Die Möglichkeit eines universellen Einsatzes der PKB in Kombination mit einer geringen Gefährdung, aber hohen Aussagekraft für den Patienten, unter Zurückhaltung bei Leave-me-alone-Läsionen, machen die PKB unklarer Knochenläsionen zu einem wertvollen diagnostischen Verfahren.AbstractPurpose. The aim of the study was to evaluate the feasibility and results of CT-guided percutanous bone biopsy (PBB) of unknown bone lesions in a representative number of patients. Methods. In 92 patients (100 biopsies) with different bone lesions CT-guided PBB was performed. Results. The rate of technical success, defined as a successful retrieval of a sufficient tissue sample which then was sent for histological evaluation, was 89% (89/100 biopsies). The diagnostic accuracy was defined as a clinically useful histological result and was obtained in 80% (80/100 biopsies). Minor complications (minimal bleedings) occurred in 3% of all biopsies, no special therapy was necessary. Osteolytic lesions (92%) were classified more accurately by PBB than osteoplastic (80%) or mixed lesions (67%). Considering the anticipated dignity of the lesions prior to PBB, the suspected malignant bone lesions had a better diagnostic accuracy of 82% than the suspected benign bone lesions with an accuracy of 50%. Conclusion. Due to its universal availability combined with a low risk and a high diagnostic value the PBB of unknown bone lesions can be regarded as a valuable diagnostic tool. However, leave-me-alone lesions should be excluded.