M Hoppe

Philipps University of Marburg, Marburg, Hesse, Germany

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Publications (37)63.51 Total impact

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    ABSTRACT: The aim of this study was to evaluate magnetic resonance phase contrast velocimetry (MRVL) as a non-invasive follow up tool to assess restenosis after percutaneous transluminal angioplasty (PTA). We prospectively investigated 51 consecutive patients who underwent PTA of the femoropopliteal region. MRVL was conducted prior, one day, six weeks, twelve weeks and 24 weeks after PTA using a circular polarized extremity coil and a gradient echo sequence (TR/TE 600/6 ms, flip angel 30 degrees, slice thickness 10 mm). Hemodynamic data, derived from the MR phase contrast sequence, allowed to calculate the degree of area stenosis of the lesion treated with PTA. These data were correlated with clinical hemodynamic parameters (ankle-brachial index and walking distance). The mean grade of area stenosis was 69% +/- 27% before PTA, 30% +/- 20% one day, 29% +/- 23% six weeks, 39% +/- 17% twelve weeks and 42% +/- 18% 24 weeks after PTA and correlated well with clinical data and the post angioplasty clinical course of the patients. Follow up measurements using MRVL are suitable to assess restenosis after PTA and allow quantifying the grade of recurrent stenosis as well as the hemodynamic consequences.
    No preview · Article · Dec 2002 · VASA.: Zeitschrift für Gefässkrankheiten. Journal for vascular diseases
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    ABSTRACT: To evaluate the potential influence of various concentrations of gadolinium (Gd)-DTPA on magnetic resonance phase contrast (MR PC) velocimetry. Imaging was done with a 1.0 T scanner using a standard Flash 2D sequence and a circular polarized extremity coil. In a validated flow phantom with a defined 75% area stenosis different concentrations of Gd-DTPA, diluted in a 10:1 water-yogurt mixture, MR PC measurements were correlated with a Doppler guide wire as gold standard. MR PC measurements correlated well with the Doppler derived data (r=0.99; P<0.01; maximum pre-stenotic velocity: 21.6+/-0.5 cm/s; maximum intra-stenotic velocity: 81.7+/-0.6 cm/s). Following Gd-DTPA administration no significant (P>0.05; Student's t-test) flow measurement changes were noted (maximum pre-stenotic velocity: 21.3+/-1.3 cm/s; maximum intra-stenotic velocity: 84.0+/-3.6 cm/s). However, delineation of the perfused lumen was enhanced after the application of Gd-DTPA. The application of Gd-DTPA does not affect MR PC velocimetry. However, the application of contrast media allowed a more accurate vessel segmentation. MR PC measurements can be reliably carried out after application of Gd-DTPA.
    No preview · Article · Nov 2002 · European Journal of Radiology
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    ABSTRACT: To evaluate the accuracy of magnetic resonance (MR) velocimetry for quantitative assessment of stenosis in patients undergoing percutaneous transluminal angioplasty (PTA). Thirty patients underwent PTA of the infrainguinal region. To assess hemodynamic parameters of lesions, MR phase-contrast velocimetry with a circular-polarized extremity receiver coil and a cardiac gated gradient echo sequence was conducted before and 1 day after PTA. Additionally, all lesions were examined by means of intravascular Doppler flow measurements (0.018-inch wire, 12 MHz). From these data, the degree of stenosis was calculated and a comparison of MR velocimetry with intravascular Doppler US was undertaken. Correlation between calculated grade of stenosis for MR velocimetry and intravascular Doppler US was good and significant (r = 0.74; P <.001). Calculated luminal stenosis grade were similar for both methods before PTA (intravascular Doppler US: 0.62 +/- 0.18, MR velocimetry: 0.54 +/- 0.19; P =.17 with paired Student t-test) and after PTA (0.25 +/- 0.23 and 0.3 +/- 0.2, respectively; P =.56). MR velocimetry results in reliable noninvasive in vivo flow measurements and allows accurate assessment of stenosis in a clinical setting.
    Full-text · Article · Apr 2001 · Journal of Vascular and Interventional Radiology
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    ABSTRACT: The aim of this study was to assess radiomorphologic and clinical features of tracheal rupture due to blunt chest trauma. From 1992 until 1998 the radiomorphologic and clinical key findings of all consecutive tracheal ruptures were retrospectively analyzed. The study included ten patients (7 men and 3 women; mean age 35 years); all had pneumothoraces which were persistent despite suction drainage. Seven patients developed a pneumomediastinum as well as a subcutaneous emphysema on conventional chest X-rays. In five patients, one major hint leading to the diagnosis was a cervical emphysema, discovered on the lateral cervical spine view. Contrast-media-enhanced thoracic CT was obtained in all ten cases and showed additional injuries (atelectasis n = 5; lung contusion n = 4; lung laceration n = 2; hematothorax n = 2 and hematomediastinum n = 4). The definite diagnosis of tracheal rupture was made by bronchoscopy, which was obtained in all patients. Tracheal rupture due to blunt chest trauma occurs rarely. Key findings were all provided by conventional chest X-ray. Tracheal rupture is suspected in front of a pneumothorax, a pneumomediastinum, or a subcutaneous emphysema on lateral cervical spine and chest films. Routine thoracic CT could also demonstrate these findings but could not confirm the definite diagnosis of an tracheal rupture except in one case; in the other 9 cases this was done by bronchoscopy. Thus, bronchoscopy should be mandatory in all suspicious cases of tracheal rupture and remains the gold standard.
    No preview · Article · Feb 2000 · European Radiology

  • No preview · Article · May 1999 · Inflammation Research
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    ABSTRACT: 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. 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. 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. 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.
    No preview · Article · Apr 1999 · Journal of Vascular and Interventional Radiology
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    ABSTRACT: Plain film radiography often underestimates the extent of injury in children with epiphyseal fracture. Especially Salter-Harris V fractures (crush fracture of the epiphyseal plate) are often primarily not detected. MRI of the ankle was performed in 10 children aged 9-17 (mean 14) years with suspected epiphyseal injury using 1.0-T Magnetom Expert. The fractures were classified according to the Salter-Harris-Rang-Odgen classification and compared with the results of plain radiography. In one case MRI could exclude epiphyseal injury; in four cases the MRI findings changed the therapeutic management. The visualisation of the fracture in three orthogonal planes and the possibility of detection of cartilage and ligamentous injury in MR imaging makes this method superior to conventional radiography and CT. With respect to radiation exposure MRI instead of CT should be used for the diagnosis of epiphyseal injuries in children.
    No preview · Article · Feb 1999 · Der Radiologe
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    ABSTRACT: To establish a morbidity and mortality conference in a radiology department as an instrument of quality assurance. Since April 1995 a monthly conference is held in the radiology department. Complications of invasive diagnostic procedures (angiography and biopsy) and minimal invasive interventions are presented. Cases of morbidity (major complications) and mortality (deceased patients, who were examined or treated in the radiology department before) are discussed. The identification of cases was possible due to a data base that included all such procedures prospectively. Twenty cases of major complications were identified and discussed during 18 morbidity and mortality conferences in 1996 and 1997. Out of the 9 patients who died in our hospital and previously had an interventional procedure in the radiology department, one case was identified as being procedure-related. An analysis of this case was performed. With a formalised structure of case detection, the morbidity and mortality conference becomes a tool of a complete analysis of complications and a meaningful instrument for the solution of problems concerning procedure-related complications.
    No preview · Article · Jan 1999 · RöFo - Fortschritte auf dem Gebiet der R
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    ABSTRACT: Die konventionelle Röntgendiagnostik unterschätzt häufig das Ausmaß der kindlichen Extremitätenfrakturen mit Epiphysenbeteiligung (Typ Salter-Harris). Insbesondere werden die Kompressionsfrakturen der Wachstumsfuge (Salter-Harris V) primär häufig nicht erkannt. Prospektiv wurden 10 Kinder im Alter von 9–17 Jahren (Durchschnittsalter=14 J.) mit Verdacht auf eine epiphysäre Fraktur der distalen Tibia magnetresonanztomographisch (1.0-Tesla Magnetom Expert), untersucht. Die MRT-Ergebnisse wurden auf der Basis der Klassifikation nach Salter-Harris-Rang-Odgen mit den konventionellen Röntgenbildern verglichen. In einem Fall, bei einem 15jährigen Patienten, gelang durch die MRT der Ausschluß einer epiphysären Verletzung. In 7 Fällen führte der MRT-Einsatz zu einer Änderung der Klassifikation nach Salter-Harris. Hieraus resultierte bei 4 Patienten ein Therapiewechsel. Da Frakturen, die sie begleitenden Knorpelläsionen und ligamentäre Verletzungen multiplanar dargestellt werden können, weist die MRT deutliche Vorteile gegenüber jeder anderen diagnostischen Methode (z.B. konventionelle Röntgendiagnostik, CT) auf. Im Hinblick auf die Strahlenexposition ist sie besonders bei Kindern eindeutig zu bevorzugen.
    No preview · Article · Jan 1999 · Der Radiologe

  • No preview · Article · Dec 1998 · RöFo - Fortschritte auf dem Gebiet der R
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    ABSTRACT: 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. 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. 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. 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.
    No preview · Article · Sep 1998 · RöFo - Fortschritte auf dem Gebiet der R

  • No preview · Article · Sep 1998 · Journal of Vascular and Interventional Radiology
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    ABSTRACT: 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. 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. Using power injectors in MRI, some pitfalls must be avoided, which can render investigations useless, especially dynamic contrast-enhanced investigations. 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.
    No preview · Article · Sep 1998 · RöFo - Fortschritte auf dem Gebiet der R

  • No preview · Article · Aug 1998 · RöFo - Fortschritte auf dem Gebiet der R
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    ABSTRACT: 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 crosssectional 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 ≤ 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 require in vivo measurements of atherosclerotic lesions to evaluate the clinical impact.
    No preview · Article · Jul 1998 · Investigative Radiology
  • I Celik · W Lorenz · B Stinner · D Duda · H Sitter · S Sauer · A Junge · M Hoppe

    No preview · Article · Feb 1998 · Inflammation Research
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    ABSTRACT: We report a case of metastatic renal cell carcinoma arising in a cadaver transplant kidney 6 years after transplantation. Due to molecular analysis of the tumor tissue we could prove that the carcinoma originated from the male donor. After tumor resection and interruption of immunotherapy, the concomitant bone and lymph node metastases resolved with alpha-interferon and interleukin-2-based immunotherapy.
    No preview · Article · Feb 1998 · European Radiology

  • No preview · Article · Jan 1998 · RöFo - Fortschritte auf dem Gebiet der R
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    ABSTRACT: Computed quantification of the extent of pleuropulmonary trauma by CT and comparison with conventional chest x-ray--Impact on therapy and correlation with mechanical ventilation support and clinical outcome. In a prospective trial, 50 patients with clinically suspicious blunt chest trauma were evaluated using CT and conventional chest x-ray. The computed quantification of ventilated lung provided by CT volumetry was correlated with the consecutive artificial respiration parameters and the clinical outcome. We found a high correlation between CT volumetry and artificial ventilation concerning maximal pressures and inspiratory oxygen concentration (FiO2, Goris-Score) (r = 0.89, Pearson). The graduation of thoracic trauma correlated highly with the duration of mechanical ventilation (r = 0.98, Pearson). Especially with regard to atelectases and lung contusions CT is superior compared to conventional chest x-ray; only 32% and 43%, respectively, were identified by conventional chest x-ray. CT allows rapid classification and quantification of pulmonary lesions after thoracic trauma and provides higher sensitivity and reliability. Because of the great correlation with the extent of artificial respiration in respect of duration and pressure, prognosis of the individual patient, as well as a differential therapy, appear possible.
    No preview · Article · Dec 1997 · RöFo - Fortschritte auf dem Gebiet der R

  • No preview · Article · Nov 1997 · RöFo - Fortschritte auf dem Gebiet der R

Publication Stats

288 Citations
63.51 Total Impact Points


  • 1994-2002
    • Philipps University of Marburg
      • Klinik für Strahlendiagnostik (Marburg)
      Marburg, Hesse, Germany
  • 1997
    • Justus-Liebig-Universität Gießen
      • Abteilung für Psychologische Diagnostik
      Gießen, Hesse, Germany
  • 1995
    • Medizinisches Zentrum
      Lippspringe, North Rhine-Westphalia, Germany