Hans Heinz Schild

Results of a multicenter study of the retrievable Tulip vena cava filter: Early clinical experience

PurposeTo evaluate clinically a new, retrievable vena caval filter in a multicenter study.MethodsThe Tulip filter is a stainless steel half-basket that is suitable for antegrade or retrograde insertion via an 8.5 Fr introducer sheath. The filter can be retrieved via the jugular approach using an 11 Fr coaxial retrieval system. Forty-eight filters were implanted via the femoral approach and 38 via the jugular approach in 83 patients. Follow-up examinations (plain films, colorcoded duplex sonography) were performed up to 3 years after filter insertion (mean 136 days) in 75 patients. Twenty-seven patients were screened by colorcoded duplex sonography for insertion site thrombosis.ResultsAn appropriate filter position was achieved in all cases. Insertion problems occurred in 3 cases; these were not due to the filter design but to an imperfect prototype insertion mechanism that has now been modified (n=2) or a manipulation error (n=1). In 2 of these cases the filters were replaced percutaneously; 1 patient required venotomy for filter removal. No further complications due to filter insertion occurred. Two filters were used as temporary devices and were successfully removed after 6 and 11 days, respectively. There was 1 fatal recurrent pulmonary embolism (PE) and 2 non-fatal PE, 5 complete and 3 partial caval occlusions, and 3 caudal migrations of the filter. Insertion site venous thrombosis was not seen in the 27 patients monitored for this complication.ConclusionPrecise placement of the Tulip filter is feasible by either access route and the device appears mechanically stable. Further observations are needed to confirm that safe filter removal is practical up to 10 days after its insertion.

Pulmonary hypertension in patients with chronic pulmonary thromboembolism: chest radiograph and CT evaluation before and after surgery.

The purpose of this study was to assess the value of morphometric data on conventional radiography and CT predicting the presence and degree of pulmonary hypertension and to assess the reversibility after surgery. On preoperative X-ray films and CT scans of 50 patients with pulmonary hypertension secondary to chronic thromboembolism, we measured the cardiothoracic ratio, basal diameter, length of cardiac contact to sternum, pulmonary trunk, right and left descending pulmonary artery, and the septum angle. These data were correlated with pulmonary arterial pressure. In 14 X-ray patients and 18 CT patients, with follow-up after surgical thromboendarterectomy the reversibility of these changes was assessed. A dilated pulmonary trunk was the most common abnormality (96% each on X-ray and CT). Pulmonary arteries were dilated on X-ray in 40% (right) and 14% (left), and on CT in 92% (right) and 96% (left). The best correlation with mean arterial pressure was found measuring the pulmonary trunk on CT (r = 0.43, p < 0.01). After surgery, reversibility was most significant for the pulmonary trunk on CT (p < 0.0001). In patients with chronic pulmonary embolism, pulmonary hypertension can best be predicted by assessing the diameter of the pulmonary trunk both on X-ray and CT. No close correlation is present between the extent of any parameter and the level of the pulmonary pressure.

Low-field magnetic resonance imaging: increased safety for pacemaker patients?

AIMS The number of low-field (<0.5 T) magnetic resonance (MR) scanners installed worldwide is increasing due to a favourable cost and safety profile and improved patient comfort using an open-scanner design. Therefore, the aim of our study was to evaluate a strategy for the safe performance of magnetic resonance imaging (MRI) at a field strength of 0.2 T, in pacemaker (PM) patients without limitations on scan region, PM dependency, or the presence of abandoned leads. METHODS AND RESULTS One hundred and fourteen PM patients, including PM-dependent patients and patients with abandoned leads, examined at a 0.2 T MR scanner due to an urgent clinical need for an MRI examination, were evaluated. All PMs were reprogrammed before MRI: if heart rate was <60 bpm, the asynchronous mode (with a rate of 80 bpm) was programmed to avoid MR-induced inhibition; if heart rate was >60 bpm, sense-only mode (ODO/OVO/OAO) was used to avoid MR-induced competitive pacing and potential proarrhythmia. Patients were monitored with electrocardiogram (ECG) and pulse oximetry. All PMs were interrogated before and after MRI, including measurement of lead impedance, pacing capture threshold (PCT), and battery voltage. All MRI scans were completed safely. No induction of arrhythmias or inhibition of PM output occurred. There were no statistically significant changes in lead impedance, PCT, or battery voltage (P>0.05). CONCLUSION Low-field MRI of PM patients, including high-risk PM patients and MRI scan regions, can be performed with an acceptable risk-benefit ratio under controlled conditions.

Nonsurgical Fluoroscopically Guided Dacryocystoplasty of Common Canalicular Obstructions

AbstractPurpose: To assess dacryocystoplasty in the treatment of epiphora due to obstructions of the common canaliculus. Methods: Twenty patients with severe epiphora due to partial (n=16) or complete (n=4) obstruction of the common canaliculus underwent fluoroscopically guided dacryocystoplasty. In all cases of incomplete obstruction balloon dilation was performed. Stent implantation was attempted in cases with complete obstruction. Dacryocystography and clinical follow-up was performed at intervals of 1 week, and 3, 6. 12, and IS months after the procedure. The mean follow-up was 6 months (range 3–18 months). Results: Balloon dilation was technically successfully performed in all patients with incomplete obstructions (n=16). In three of four patients with complete obstruction stent implantation was performed successfully. Subsequent to failure of stent implantation in one of these patients balloon dilation was performed instead. The long-term primary patency rate in patients with incomplete obstructions was 88% (n=14/16). In three of four cases with complete obstruction long-term patency was achieved during follow-up. Severe complications, infections, or punctal splitting were not observed. Conclusion: Fluoroscopically guided balloon dacryocystoplasty is a feasible nonsurgical therapy in canalicular obstructions with good clinical results that may be used as an alternative to surgical procedures. In patients with complete obstructions stent placement is possible but further investigations are needed to assess the procedural and long-term results.

Contrast Material for Abdominal Dynamic Contrast-Enhanced 3D MR Angiography With Parallel Imaging: Intraindividual Equimolar Comparison of a Macrocyclic 1.0 M Gadolinium Chelate and a Linear Ionic 0.5 M Gadolinium Chelate

OBJECTIVE The purpose of this study was to compare a macrocyclic 1.0 M contrast agent with a linear ionic 0.5 M contrast agent at equimolar dosage in regard to image quality and number of vessel segments visualized at abdominal dynamic contrast-enhanced 3D MR angiography. SUBJECTS AND METHODS In an intraindividual comparative study, 15 patients (six women, nine men; mean age, 53 +/- 12.1 years; range, 25-72 years) underwent 32 1.5-T whole-body contrast-enhanced 3D MR angiographic examinations performed with parallel imaging technique. At random and in separate sessions, each patient was examined after IV injection of 0.1 mmol/kg body weight 1.0 M macrocyclic gadobutrol and 0.5 M linear ionic gadopentetate dimeglumine. Three-dimensional data sets were acquired in the arterial, portal venous, and venous phases with identical imaging protocols. Quantitative analysis included contrast measurements of vessels compared with adjacent background tissue (Students t test). Qualitative analysis was performed independently by two radiologists with regard to visualization of arterial and venous vessel segments and overall image quality (Wilcoxons test). RESULTS Visualization of individual vessel segments was rated significantly better after administration of 1.0 M macrocyclic gadobutrol compared with 0.5 M linear ionic gadopentetate dimeglumine (p < 0.001). Overall image quality was superior with 1.0 M macrocyclic gadobutrol, but the difference was not significant. Vessel-to-background contrast after injection of 1.0 M macrocyclic gadobutrol was significantly higher (arterial phase, 0.90, p = 0.02; portal venous phase, 0.78, p = 0.0002; venous phase, 0.74, p = 0.0002) compared with 0.5 M linear ionic gadopentetate dimeglumine (arterial phase, 0.89; portal venous phase, 0.73; venous phase, 0.67). CONCLUSION At abdominal contrast-enhanced 3D MR angiography, depiction of small abdominal vessels was significantly better and vessel-to-tissue contrast significantly higher with 1.0 M macrocyclic gadobutrol than with an equimolar dose of 0.5 M linear ionic gadopentetate dimeglumine.

Intraindividual quantitative and qualitative comparison of gadopentetate dimeglumine and gadobutrol in time-resolved contrast-enhanced 4-dimensional magnetic resonance angiography in minipigs.

ObjectivesThe concentration and relaxivities of contrast agents affect quantitative and qualitative image quality in contrast-enhanced time-resolved 4-dimensional magnetic resonance angiography (4D-MRA). Gadobutrol has a high relaxivity and is the only gadolinium (Gd)-based contrast agent approved for clinical use at a 1 M concentration. This promises to confer superior bolus characteristics by generating a steeper and shorter bolus with a higher peak Gd concentration. The purpose of this study was to quantitatively examine bolus characteristics of 1 M gadobutrol compared with 0.5 M gadopentetate dimeglumine and to evaluate image quality in thoracoabdominal 4D-MRA. Materials and MethodsA total of 7 Goettingen minipigs received dynamic computed tomography (CT) on a clinical 64-slice CT (transverse slices, 80 kV, 20 seconds, 0.3 s/dynamic frame) and 4D-MRA (time-resolved imaging with stochastic trajectories; 1. transverse slices, 30 seconds, 0.49 s/frame; 2. coronal slices, 70 seconds, 1.3 s/frame) on a 1.5-T clinical whole-body magnetic resonance imaging under general anesthesia using gadopentetate dimeglumine and gadobutrol in an intraindividual comparative study. Computed tomography attenuations were converted into Gd concentrations on the basis of previous phantom experiments. Quantitative analysis included measurements of the full width at half maximum, time-to-peak intervals, and peak of each bolus in dynamic CT and transverse 4D-MRA. These studies were carried out at equivalent contrast agent flow rates of 1 mL/s. Quantitative analysis (7 arteries and veins) and qualitative image analysis were performed on coronal thoracoabdominal 4D-MRA studies carried out at flow rates of 1 mL/s and, in the case of gadopentetate dimeglumine, also at molarity-adjusted flow rates of 2 mL/s. ResultsThe bolus in both transverse 4D-MRA and dynamic CT was significantly narrower (full width at half maximum), earlier (time to peak), and higher (signal intensity enhancement in 4D-MRA, Gd concentration in dynamic CT) when using gadobutrol instead of gadopentetate dimeglumine at a flow rate of 1.0 mL/s (P = 0.008−< 0.0001). In thoracoabdominal 4D-MRA, the signal intensity level and overall image quality were highest in examinations with gadobutrol, followed by examinations with gadopentetate dimeglumine at flow rates of 2 mL/s, and lowest in examinations with gadopentetate dimeglumine at flow rates of 1 mL/s. ConclusionsA more compact bolus shape was observed after administration of gadobutrol compared with gadopentetate dimeglumine in minipigs. This was demonstrated both in 4D-MRA, where Gd concentration, relaxivity, and the image-acquisition technique play a role, and in CT, where the signal intensity depends only on the Gd concentration. The overall image quality was rated higher in examinations with 1.0 M gadobutrol than with 0.5 M gadopentetate dimeglumine.

Evaluation of polyurethane nasolacrimal duct stents: in vivo studies in New Zealand rabbits.

The purpose of this study was to evaluate the radiographic and biological effects of different polyurethane nasolacrimal duct stents in an animal model. Fifteen polyurethane nasolacrimal duct stents (n = 5 mushroom-type stents, n = 5 newly designed S-shaped TearLeader stents without hydrophilic coating, and n = 5 S-shaped TearLeader stents with hydrophilic coating) were implanted in the nasolacrimal ducts of eight unaffected New Zealand rabbits. One nasolacrimal system served as control. Clinical and radiographic follow-up was performed at 1-, 2-, and 4-week intervals, then after a 3-month interval, after which the animals were euthanized. All stents were implanted without major periprocedural complications. The stents proved to be patent by the end of the procedure. During follow-up, all mushroom-type stents were occluded at 4 weeks. None of these stents opened to forced irrigation. Clinically, all rabbits demonstrated severe dacryocystitis. Three out of five TearLeader stents without hydrophilic coating were blocked at 4 weeks; one out of five was open to irrigation. Best results were observed in the stent group with hydrophilic coating. Follow-up dacryocystography demonstrated patent stents in nasolacrimal ducts of all animals after 4 weeks. In only one of five cases, the coated stent became partially occluded after 2 months. These animals were free of clinical symptoms. After 3 months, at least three out of five stents still opened to forced irrigation and only one stent was completely blocked. Dislocation of the stents was not observed. Refinement of the stent surface and stent design improves the results of nasolacrimal duct stenting in this animal model. Implantation of hydrophilic-coated S-shaped stents is highly superior to conventional mushroom-type stents and noncoated stent types. Hydrophilic coating seems to prevent foreign-body reactions, resulting in maximized stent patency.

Cone-Beam Computed Tomography (CBCT) Dacryocystography for Imaging of the Nasolacrimal Duct System

AbstractPurpose:To evaluate the usefulness and safety of cone-beam computed tomography (CBCT) dacryocystography in detecting lesions, identifying coexisting soft-tissue changes and determining treatment options in patients with epiphora.Patients and Methods:Unilateral digital subtraction dacryocystography and CBCT dacryocystography were carried out on 45 patients. Stenoses and occlusions were identified and coexisting changes such as septal deviation and dacryoliths were noted. The diameter of the bony lacrimal duct of affected and unaffected side was measured and related to the clinically evident epiphora. An attempt was made to base the subsequent therapeutic planning on the CBCT dacryocystographic findings. Additionally, the radiation dose levels for CBCT dacryocystography in comparison to those of multislice computed tomography (MSCT) were evaluated in a standardized head-neck Rando-Alderson phantom.Results:Nasolacrimal duct obstructions were present in 37/45 patients, 18 with a stenosis and 19 with an occlusion in parts of the lacrimal outflow system. The minimal bony diameter of the side with epiphora was significantly decreased compared to the unaffected side. Coexisting soft-tissue changes did not correlate significantly with the clinical sign of epiphora. Eight patients showed no underlying reason for the epiphora and were treated conservatively. A total of eleven patients received interventional therapy for their stenosis and 23 patients had to be treated surgically. A further three patients received medical treatment for infection, before surgery and interventional therapy, respectively, were carried out. Dose levels for CBCT imaging remained far below those of MSCT.Conclusion:CBCT dacryocystography is a safe and time-efficient modality for assessing the nasolacrimal duct system in patients with epiphora. CBCT dacryocystography provides detailed images of the nasolacrimal drainage system, surrounding soft tissue, and bony structures in one diagnostic tour. It allows clear measurement of the bony nasolacrimal duct and displays information beyond that of the drainage lumen, improving the planning of therapeutic interventional and surgical procedures.ZusammenfassungZiel:Evaluation der dreidimensionalen (3-D) Flachdetektor-Rotationsdakryozystographie zur funktionellen und morphologischen Diagnostik der ableitenden Tränenwege bei Patienten mit Epiphora.Patienten und Methodik:Bei 45 Patienten (32 Frauen, 13 Männer, mittleres Alter 57 Jahre) mit einseitiger Epiphora und dem klinischen Verdacht auf einen stenosierenden Prozess der ableitenden Tränenwege wurden insgesamt 45 Tränenwegsdarstellungen durchgeführt. Bei allen Patienten wurden beide knöchernen Tränen-Nasen-Kanäle vermessen. Die 3-D-Rota- tionsdakryozystographien wurden an einer Flachdetektor-Angiographieanlage (Philips Allura Xper FD20, Philips Medical Systems, Best, Niederlande) in einem Messbereich von 240° C-Bogen-Rotation durchgeführt. Die 3-D-Datensätze wurden bezüglich der Beurteilbarkeit der morphologischen und funktionellen Ursachen der Epiphora sowie der Planungsmöglichkeiten weiterer Therapieoptionen ausgewertet. Zur Beurteilung der bei der 3-D-Rotationsdakryozystographie auftretenden Strahlenexposition für die strahlensensiblen Risikoorgane (Augenlinse, Parotis und Schilddrüse) wurden vorab Dosismessungen an einem Kopf-Hals-Phantom durchgeführt und die Ergebnisse mit denen einer Standard-Mehrschicht-Computertomographie (MSCT) des Gesichtsschädels verglichen.Ergebnisse:Die technische Durchführbarkeit und Auswertbarkeit waren bei allen 45 Untersuchungen gegeben. Bei acht (17,8%) der untersuchten Tränenapparate zeigte sich trotz bestehender Symptomatik der Epiphora eine unauffällige Darstellung der ableitenden Tränenwege. Ein pathologischer Befund bestand bei 37 (82,2%) der untersuchten Tränenapparate. In 18 Fällen (48,6%) lag der Abflussbehinderung eine Stenose, in 19 Fällen (51,4%) ein Verschluss der ableitenden Tränenwege zugrunde. Bei 34 der 45 Patienten konnten ein oder mehrere Zusatzbefunde erhoben werden. Die statistische Analyse der Zusatzbefunde ergab jedoch keinen signifikanten Zusammenhang zwischen dem Vorliegen eines oder mehrerer dieser Zusatzbefunde und dem Auftreten von Epiphora. Bei der Ausmessung des minimalen knöchernen Durchmessers des Tränen-Nasen-Kanals konnte jedoch eine signifikante Korrelation zwischen einem kleinen Durchmesser der symptomatischen Seite gegenüber der asymptomatischen Gegenseite nachgewiesen werden (p = 0,003). Die Strahlenexposition für die Augenlinse bei der 3-D-Rotationsdakryozystographie betrug 4,1 mSv und war damit geringer als die einer üblicherweise durchgeführten MSCT. Die weiterführende Therapieplanung war in allen Fällen ohne die Durchführung zusätzlicher radiologischer bildgebender Verfahren möglich.Schlussfolgerung:Die 3-D-Rotationsdakryozystographie bietet erstmals eine Option zur umfassenden Darstellung der ableitenden Tränenwege, bei der außerdem eine suffiziente Beurteilung der angrenzenden Weichteile und knöchernen Strukturen möglich ist. Bei Patienten mit Epiphora sollte die 3-D-Rotationsdakryozystographie aufgrund der im Vergleich zur CT geringeren Strahlenexposition als Standardverfahren zur bildgebenden Diagnostik der ableitenden Tränenwege eingesetzt werden. Hierdurch lässt sich der für die Abklärung der Symptomatik erforderliche apparatetechnische Aufwand bei gleichzeitiger Reduktion von Strahlenexposition des Patienten, Untersuchungszeit und -aufwand verringern.

Lymphatic Interventions for Treatment of Chylothorax

PURPOSE To determine effectiveness of lymphatic interventional procedures for treatment of chylothorax. MATERIAL AND METHODS Analysis of interventions performed from 2001 to 2014. RESULTS In 21 patients with therapy resistant chylothorax a lymphatic radiological intervention was attempted, which could be performed in 19 cases: 17 thoracic duct embolizations (15 transabdominal, one transzervical and one retrograde transvenous procedure), 2 percutaneous destructions of lymphatic vessels, one CT-guided injection of ethanol next to a duplicated thoracic duct. Fourteen of seventeen (82.3 %) of the technically successful embolizations lead to clinical cure. This encluded three patients with prior unsuccessful surgical thoracic duct ligation. Also the injection of ethanol was clinically effective. Complications were a bile peritonitis requiring operation, and one clinical deterioration of unknown cause. CONCLUSION Interventional lymphatic procedures allow for effective treatment in many cases of chylothorax, and should be considered early during treatment. KEY POINTS • Thoracic duct embolization is an effective treatment method for chylothorax. • If embolization is impossible, percutaneous lymphatic destruction or injection of sclerosants/tissue adhesive next to the thoracic duct may be tried.

The value of intravoxel incoherent motion model-based diffusion-weighted imaging for outcome prediction in resin-based radioembolization of breast cancer liver metastases

Purpose To evaluate prognostic values of clinical and diffusion-weighted magnetic resonance imaging-derived intravoxel incoherent motion (IVIM) parameters in patients undergoing primary radioembolization for metastatic breast cancer liver metastases. Subjects and methods A total of 21 females (mean age 54 years, range 43–72 years) with liver-dominant metastatic breast cancer underwent standard liver magnetic resonance imaging (1.5 T, diffusion-weighted imaging with b-values of 0, 50, and 800 s/mm2) before and 4–6 weeks after radioembolization. The IVIM model-derived estimated diffusion coefficient D’ and the perfusion fraction f’ were evaluated by averaging the values of the two largest treated metastases in each patient. Kaplan–Meier and Cox regression analyses for overall survival (OS) were performed. Investigated parameters were changes in f’- and D’-values after therapy, age, sex, Eastern Cooperative Oncology Group (ECOG) status, grading of primary tumor, hepatic tumor burden, presence of extrahepatic disease, baseline bilirubin, previous bevacizumab therapy, early stasis during radioembolization, chemotherapy after radioembolization, repeated radioembolization and Response Evaluation Criteria in Solid Tumors (RECIST) response at 6-week follow-up. Results Median OS after radioembolization was 6 (range 1.5–54.9) months. In patients with therapy-induced decreasing or stable f’-values, median OS was significantly longer than in those with increased f’-values (7.6 [range 2.6–54.9] vs 2.6 [range 1.5–17.4] months, P<0.0001). Longer median OS was also seen in patients with increased D’-values (6 [range 1.6–54.9] vs 2.8 [range 1.5–17.4] months, P=0.008). Patients with remission or stable disease (responders) according to RECIST survived longer than nonresponders (7.2 [range 2.6–54.9] vs 2.6 [range 1.5–17.4] months, P<0.0001). An ECOG status ≤1 resulted in longer median OS than >1 (7.6 [range 2.6–54.9] vs 1.7 [range 1.5–4.5] months, P<0.0001). Pretreatment IVIM parameters and the other clinical characteristics were not associated with OS. Classification by f’-value changes and ECOG status remained as independent predictors of OS on multivariate analysis, while RECIST response and D’-value changes did not predict survival. Conclusion Following radioembolization of breast cancer liver metastases, early changes in the IVIM model-derived perfusion fraction f’ and baseline ECOG score were predictive of patient outcome, and may thus help to guide treatment strategy.