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23 results on '"Raatschen, Hans-Juergen"'

10. Factors influencing radiation dose in abdominal CT for tumour staging

Author

Raatschen, Hans-Juergen

Subjects
Staging, genetic structures, Oncology, Abdomen, Radioprotection / Radiation dose, Diagnostic procedure, CT
Abstract

Aims and objectives Methods and materials Results Conclusion Personal information References, Aims and objectives: Oncologic patients undergo CT examinations for tumour staging at least every three months during therapy. Using a dose management software (DoseWatch, GE®, Strasbourg, France), we observed intraindividual variations in patient's dose...

Published
2017
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11. Individualised CTPA injection protocol optimises contrast use and increases arterial attenuation

Author

Raatschen, Hans-Juergen

Subjects
genetic structures, Pulmonary vessels, Contrast agent-intravenous, Lung, CT-Angiography, Embolism / Thrombosis, Contrast agents
Abstract

Aims and objectives Methods and materials Results Conclusion Personal information References, Aims and objectives: Pulmonary CT angiography has a sensitivity of 90-100% in the detection of pulmonary embolism and is considered the first-line imaging modality in suspected PE [1].However, poor vascular enhancement as well as attenuation artifacts caused by a...

Published
2016
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15. Vascular Permeability during Antiangiogenesis Treatment: MR Imaging Assay Results as Biomarker for Subsequent Tumor Growth in Rats1

Author

Raatschen, Hans-Juergen, Simon, Gerhard H., Fu, Yanjun, Sennino, Barbara, Shames, David M., Wendland, Michael F., McDonald, Donald M., and Brasch, Robert C.

Subjects
Gadolinium DTPA, Analysis of Variance, Neovascularization, Pathologic, Antibodies, Monoclonal, Contrast Media, Mammary Neoplasms, Experimental, Angiogenesis Inhibitors, Antibodies, Monoclonal, Humanized, Magnetic Resonance Imaging, Rats, Bevacizumab, Biomarkers, Tumor, Image Processing, Computer-Assisted, Animals, Female, sense organs, Prospective Studies, Least-Squares Analysis, Algorithms, Original Research
Abstract

To prospectively evaluate in rats the acute change in tumor vascular leakiness (K(PS)) assayed at magnetic resonance (MR) imaging after a single dose of the angiogenesis inhibitor bevacizumab as a predictive biomarker of tumor growth response after a prolonged treatment course.Institutional animal care and use committee approval was obtained. Seventeen female rats with implanted human breast cancers underwent dynamic albumin-(Gd-DTPA)(30)-enhanced MR imaging followed by an initial dose of bevacizumab or saline (as a control). Treatment was continued every 3rd day, for a total of four doses at five possible dose levels: 0 mg bevacizumab (n = 4 [control rats]), 0.1 mg bevacizumab (n = 3), 0.25 mg bevacizumab (n = 2), 0.5 mg bevacizumab (n = 5), and 1.0 mg bevacizumab (n = 3). A second MR imaging examination was performed 24 hours after the initial dose to enable calculation of the acute change in MR imaging-assayed leakiness, or Delta K(PS). This acute change in K(PS) at MR imaging was correlated with tumor growth response for each cancer at the completion of the 11-day treatment course. For statistical analyses, an unpaired two-tailed t test, analysis of variance, and linear regression analyses were used.The MR imaging-assayed change in tumor microvascular leakiness, tested as a potential biomarker, correlated strongly with tumor growth rate (R(2) = 0.74, P.001). K(PS) and tumor growth decreased significantly in all bevacizumab-treated cancers compared with these values in control group cancers (P.05).The MR imaging-assayed acute change in vascular leakiness after a single dose of bevacizumab was an early, measurable predictive biomarker of tumor angiogenesis treatment response.

Published
2008

23. Non-invasive quantification of anti-angiogenic therapy by contrast-enhanced MRI in experimental pancreatic cancer

Author

Raatschen, Hans-Juergen, Fischer, Susanne, Zsivcsec, Benjamin, Schoenfeld, Christian-Olaf, Hotz, Birgit, Buhr, Heinz, and Hotz, Hubert

Abstract

BackgroundCurrently, early changes of tumor vasculature after angiogenesis inhibition can only be evaluated by histopathology, a method not suitable in a clinical setting.PurposeTo quantify effects of different angiogenesis inhibitors on the microvasculature of orthotopically implanted pancreatic cancers by contrast-enhanced magnetic resonance imaging (MRI) in order to establish a non-invasive technique for monitoring antiangiogenic cancer treatment.Material and MethodsDSL-6A/C1 pancreatic cancers were implanted in the pancreas of 109 Lewis rats. Three weeks later, antiangiogenic treatment was initiated by administration of Bevacizumab (n = 38) or Suramin (n = 27) while the control group (n = 44) remained untreated. Dynamic MRI was performed 24 h, 1 week, and 4 weeks after treatment initiation. Fractional tumor plasma volume (fPV, %) and vascular permeability (KPS, mL/min/100 cc) were calculated based on the MRI data by using a pharmacokinetic model.ResultsTwenty-four hours after the initial dose, a significant decline in KPSwas observed in the Bevacizumab group compared to the control and Suramin group (0.002 ± 0.008; 0.057 ± 0.046 and 0.064 ± 0.062 (mean ± SD); P < 0.05). At 1 week, fPV was significantly smaller in Bevacizumab and Suramin treated tumors compared to control tumors (6.25 ± 2.74, 7.47 ± 3.44, and 15.10 ± 9.97, respectively; P < 0.05). Differences in tumor volumes were first observed after 4 weeks of treatment with significantly larger control tumors (4380.3 ± 1590.6 vs. 869.6 ± 717.2 and 1676.5 ± 2524.1 mm3; P < 0.05).ConclusionDynamic MRI can quantify antiangiogenic effects on tumor microvasculature before changes in tumor volumes are detectable. Thus, this technique is a reasonable addition to morphological MRI and may be applied as an alternative to histopathology.

Published
1961
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