Karsten Krueger

Percutaneous Treatment of a Splenic Artery Pseudoaneurysm by Thrombin Injection

Pseudoaneurysms in the visceral arteries are rare complications of pancreatitis. In the reported case, a 42-year-old man with a splenic pseudoaneurysm was successfully treated by computed tomography (CT)-guided direct thrombin injection into the pseudoaneurysm lumen. Selective catheterization of the splenic artery had proven technically impossible. During the procedure, contrast medium was injected via a pigtail catheter into the aorta for planning, correct positioning of the needle tip, and control imaging after injection. CT examinations 1 day, 3 weeks, and 6 months after treatment demonstrated complete occlusion shrinkage of the pseudoaneurysm, and the patient was symptom-free.

MRI and CT of adenomatous tumours of the middle ear

Abstract We report three adenomatous middle-ear tumours, an adenoma, an adenocarcinoma and a semimalignant adenomatous tumour, with special attention to CT and MRI findings. In all cases we found small intratympanic masses in which the ossicles were embedded. All showed contrast enhancement and similar signal intensity as brain tissue on T1- and T2-weighted images. The biological nature of the tumours was not reflected by the imaging or operative findings.

Endovascular γ-irradiation to prevent recurrent femoral in-stent restenosis

Abstract We report about a patient with twice recurrence of femoral in-stent restenoses. Centered endoluminal γ-irradiation with 192 iridium was performed immediately after the second stent recanalization. The irradiation dose was 14 Gy calculated at 2-mm depth of vessel wall. One-year follow-up demonstrates neither clinical nor angiographic evidence of restenosis.

Successful treatment of a type-II endoleak with percutaneous CT-guided thrombin injection in a patient after endovascular abdominal aortic aneurysm repair

The persistence of blood flow outside the graft but inside the aneurysm sac after endovascular treatment of the AAA is called endoleak. Strategies of treatment vary depending on the type of endoleak. Type-II endoleaks are usually treated by intraarterial embolization of the feeding vessels; however, this may be tedious, time-consuming, and sometimes impossible. We treated a 77-year-old man with a type-II endoleak after uneventful endograft (Zenith, Cook, William Europe, Denmark) placement with CT-guided injection of thrombin. A small endoleak originating from a persistent flow through a lumbar artery was detected by contrast-enhanced helical CT (Fig. 1) and intraarterial angiography. Selective catheterization of the lumbar artery via the internal iliac artery was twice technically impossible. Firstly, a pigtail catheter was placed in the aorta. After the patient was positioned in a prone position, a helical CT scan was performed while contrast medium was injected (30 ml, 5 ml/s) via the pigtail catheter in order to confirm the localization of the endoleak. A CT-guided puncture was performed with a 22-cm-long needle (diameter 0.7 mm; Fig. 2). L E T T E R T O T H E E D I T O R

How thrombus model impacts the in vitro study of interventional thrombectomy procedures.

Rationale and Objectives:Numerous experimental models are used to investigate the effectiveness of thrombectomy devices. We aimed to study the systematic effects of different in vitro thrombus models on the results of experimental thrombectomy and examined how thrombi formed in vitro and ex vivo differ. Methods:Three variables involved in human in vitro thrombogenesis were investigated: spontaneous or thrombin-induced clotting, age (1 or 5 days old), and storage temperature (4°C or 21°C). The fibrin content of in vitro and fresh or old ex vivo thrombi was measured by histologic studies. Ten experiments were performed with each of 8 different in vitro thrombus types using (1) ultrasound thrombolysis, (2) Oasis thrombectomy, (3) Amplatz thrombectomy, and (4) Straub-Rotarex catheters. Thrombus weight was measured after standardized treatment. Results:The fibrin content was markedly lower in all in vitro than in fresh and old ex vivo thrombi. In vitro thrombus type had no impact on the effectiveness of ultrasound thrombolysis and Amplatz thrombectomy. Thrombogenesis type affected Oasis and Straub-Rotarex catheter use. Storage temperature had a systematic impact on the outcome of Oasis thrombectomies. Conclusion:The fibrin content of in vitro thrombi differs substantially from that of fresh and old ex vivo human thrombi. Experimental conditions may systematically impact experimental evaluation of thrombectomy procedures. In vitro thrombi with thrombin-induced thrombogenesis should be favored for use in thrombectomy experiments.

Late Resolution of Diffusion-Weighted MRI Changes in a Patient With Prolonged Reversible Ischemic Neurological Deficit After Thrombolytic Therapy

Background Reduced apparent diffusion coefficients (ADCs) correlate with cerebral ischemia. The combination of ADC with techniques to measure cerebral perfusion may help to assess the effect of treatment. Case Description—The authors describe a patient who experienced an acute stroke with hemianopia, consequently treated with intravenous recombinant tissue plasminogen activator. Positron emission tomographic imaging and MRI, including diffusion-weighted MRI, were performed during and shortly after treatment with recombinant tissue plasminogen activator and 34 to 35 hours later. Cerebral perfusion of the left occipital region was reduced to 74%. Diffusion-weighted MRI detected a territory of restricted water movement in the corresponding area. Further magnetic resonance sequences did not show any pathologies. In follow-up, positron emission tomography demonstrated reperfusion. The volume of diffusion and ADC abnormalities detected by MRI decreased markedly. A few hours later, the patient recovered completely. A third MRI examination 10 days later showed normal findings. Conclusions In a patient with prolonged reversible ischemic neurological deficit, resolution of early diffusion changes corresponded to cerebral reperfusion and to the recovery of clinical symptoms.

Experimental and clinical evaluation of the PARIS centering catheter for delivery of endovascular gamma-irradiation of femoropopliteal stenoses.

PURPOSE To investigate the effect of aortic bifurcation and iliac geometry on centered endovascular irradiation (CEI) of femoropopliteal arteries and evaluate procedure-related complications. MATERIALS AND METHODS In an experimental tubing model, crossover delivery of the dummy wire by an afterloader using different sheaths (Type I: noncrossover; Type II: crossover, length 40 cm; Type III: crossover, length 65 cm) was examined at simulated angles between 20 degrees -100 degrees (aortic bifurcation) and 0 degrees -100 degrees (iliac vessels). In the clinical phase, 28 heparin-anticoagulated patients underwent percutaneous transluminal angioplasty (PTA) for femoropopliteal stenoses followed by CEI (192-iridium, 14 Gray at 2 mm depth of the vessel wall) delivered with the centering catheter (crossover from contralateral leg using a 65-cm-long 8F sheath in 13 patients, noncrossover from ipsilateral leg using a 10-cm 8F sheath in 15 patients). Measurement of the aortic bifurcation angle before advancement of the crossover sheath and rating of iliac artery tortuosity on both sides was retrospectively performed on angiograms. Fifteen controls received no post-PTA CEI. RESULTS Experimental delivery of the dummy wire was not possible at aortic angles less than 40 degrees with Type I, 60 degrees with Type II, and 30 degrees with Type III sheaths. Advancement of the centering catheter was possible in all patients. CEI failed in two patients with crossover (aortic angle <40 degrees ) and in one obese patient with antegrade approach because advancement of the dummy wire was impossible. Thromboembolism rate was 4.6% during irradiation (2.3% after PTA alone). CONCLUSIONS CEI in femoropopliteal arteries has a risk of procedure-related thromboembolic complications. Efficacy is affected by vessel geometry.

Novel Dynamic Hepatic Magnetic Resonance Imaging Strategy Using Advanced Parallel Acquisition, Rhythmic Breath-Hold Technique, and Gadoxetate Disodium Enhancement.

ObjectiveThe aim of the study was to evaluate image quality of a dynamic hepatic magnetic resonance (MR) imaging strategy based on advanced parallel acquisition combined with rhythmic breath-hold and gadoxetate disodium enhancement. Materials and MethodsTwenty-seven patients (21 male/6 female; mean age, 57.3 years) were enrolled in this institutional review board–approved study and underwent MR imaging at 3 T. The sequence (T1 3-dimensional gradient-recalled echo; acceleration factor, 4; reconstruction mode; controlled aliasing in parallel imaging resulting in higher acceleration factors; acquisition time, 10.4 seconds) was repeated at 8 fixed time points within the 3 minutes after contrast agent injection. Image quality was evaluated on a 5-point scale (1, excellent; 5, nondiagnostic). Dynamic sequences were classified according to perfusion phases and contrast characteristics. Artifacts and position of the liver in the z axis were recorded and analyzed. ResultsOverall image quality was found to be 1.44 (95% confidence interval, 1.18–1.71). Contrast was scored as excellent in 25 of 27 patients for central vessels and 22 of 27 patients for peripheral vessels. Adequate-quality arterial-phase images were obtained in all 27 patients. Double arterial and single arterial phases were acquired in 13 of 27 and 14 of 27 patients (n = 6 arterial dominant, n = 8 early arterial phases), respectively. In 1 (3.7%) of 27 patients, severe respiratory artifacts were seen during an early arterial phase. Artifacts were observed in 21 of 27 patients and rated as mild in 19 of these. Compromised quality was related to receiver coils (17 of 29), parallel imaging (6 of 29), breathing (3 of 29), and other causes (3 of 29). The position of the liver throughout the dynamic phases was highly constant, with a greatest mean shift of +2.9 mm throughout the first dynamic acquisition. ConclusionsAdvanced parallel acquisition with rhythmic breath-hold and gadoxetate injection allows arterial phase imaging without breathing artifacts; a decelerated yet normal breathing pattern results in very robust breath-hold depth.

Unifocal epitheloid hemangioendothelioma of the humerus: case report and review of the literature

Abstract A patient with an epitheloid hemangioendothelioma of the proximal humerus is presented. Selective embolization of the tumor-supplying vessels was performed before total excision and substitution by an isoelastic prothesis. The patient shows no local recurrence or tumor spreading 2.5 years after the operation.