Thomas C Lauenstein

University Hospital Essen, Essen, North Rhine-Westphalia, Germany

Are you Thomas C Lauenstein?

Claim your profile

Publications (296)717.87 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: T1-weighted (T1w) contrast-enhanced magnetic resonance imaging (MRI) of the small bowel at 1.5 T magnetic field strength has become a standard technique in investigating diseases of the small bowel. High-field MRI potentially offers improved soft tissue contrast and spatial resolution, providing increased image detail. The purpose of this study was to evaluate the feasibility of contrast-enhanced small bowel MRI at 7 T and to compare results with 1.5 T. Twelve healthy volunteers underwent small bowel MRI on a 1.5 T and 7 T MRI system. A coronal fat-saturated T1w spoiled gradient-echo sequence (3-dimensional [3D] FLASH) was applied precontrast and at 20 seconds, 75 seconds, and 120 seconds after intravenous contrast administration. Furthermore, late-phase coronal and axial fat-saturated T1w 2-dimensional (2D) FLASH data sets were acquired. Visual evaluation of tissue contrast and image detail of the small bowel wall and mesentery as well as contrast ratios were compared between 1.5 T and 7 T in an intraindividual comparison. In addition, subjective ratings of image impairment by artifacts were assessed at both field strengths. Magnetic resonance imaging of the small bowel at 7 T revealed equal tissue contrast and image detail compared with 1.5 T. Higher contrast and improved image detail of mesentery structures at 7 T were found in nonenhanced 3D FLASH. Quantitatively measured contrast between the bowel wall and bowel lumen showed significantly lower contrast at 7 T in nonenhanced 3D FLASH and in late-phase 2D FLASH. Image quality was more impaired at 7 T compared with 1.5 T, mainly due to increased susceptibility artifacts and B1 inhomogeneities. T1-weighted contrast-enhanced MRI of the small bowel at 7 T represents a promising MR technique for establishing ultra-high magnetic field strengths in clinical applications. Despite increased artifacts at 7 T, depiction of the small bowel was achieved with comparable quality to the current state-of-the-art field strength of 1.5 T. Assessment of potential diagnostic benefits should be the focus of future high-field MRI studies.
    Investigative radiology 05/2015; DOI:10.1097/RLI.0000000000000161 · 4.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To compare the utility of gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA), a liver-specific magnetic resonance (MR) imaging contrast agent, versus gadobutrol for treatment response evaluation of hepatocellular carcinoma (HCC) after radioembolization. This prospective study included 50 patients with HCC undergoing radioembolization. All patients underwent contrast-enhanced computed tomography (CT) and MR imaging with gadobutrol and Gd-EOB-DTPA on 2 consecutive days before radioembolization and 30 days, 90 days, 180 days, and 270 days after radioembolization. The standard of reference indicating tumor progression was CT combined with either α-fetoprotein or γ-glutamyltransferase. Gadobutrol-enhanced MR imaging, Gd-EOB-DTPA-enhanced MR imaging without late phase imaging (Gd-EOB-DTPA-), and Gd-EOB-DTPA-enhanced MR imaging with late phase imaging (Gd-EOB-DTPA+) were evaluated by two radiologists in consensus using a 4-point scale: 1 = definitely no tumor progression; 2 = probably no tumor progression; 3 = probably tumor progression; 4 = definitely tumor progression. Diagnostic accuracy was assessed with receiver operating characteristic analysis. Tumor progression was detected in 14 of 82 study visits according to the reference standard. Pairwise comparison of the area under the curve showed a tendency toward a larger area under the curve for Gd-EOB-DTPA+ compared with gadobutrol (P = .056). Sensitivity and specificity were higher in Gd-EOB-DTPA+ (0.929 and 0.971) than in Gd-EOB-DTPA- (0.786 and 0.941) or gadobutrol (0.643 and 0.956). In two cases, tumor progression was detected by Gd-EOB-DTPA+ and by an increase in α-fetoprotein, but not by CT, gadobutrol, or Gd-EOB-DTPA-. Gd-EOB-DTPA+ MR imaging was not inferior to gadobutrol-enhanced MR imaging in therapy response evaluation after radioembolization and may allow a more accurate detection of early HCC recurrence in single cases. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.
    Journal of vascular and interventional radiology: JVIR 04/2015; DOI:10.1016/j.jvir.2015.03.009 · 2.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The contrast enhancement of pulmonary nodules is a differential diagnostic criterion which can be helpful in staging investigations. To investigate the impact of dual-energy computed tomography (DECT) with regards to the evaluation of pulmonary nodules with emphasis on metastatic lesions. DECT scans of the thorax were performed in 70 consecutive patients. Data of the lung were acquired in the arterial and in delayed venous phase. The virtual native and overlay image data based on arterial and delayed venous phase of these lesions were compared using CT density values (HU) within the nodule tested for statistical significance. A total of 156 pulmonary lesions ≥5 mm were identified on 70 DECT scans. There were no significant differences between the CT-value measurements in the virtual native images based on the arterial and delayed venous phase (27.9+/-3.9 HU vs.28.1+/-4.2 HU, P = 0.89) and between the CT-value measurements in the overlay images based on the arterial und delayed venous phase (35.5+/-6.8 HU vs. 36.6+/-5.0 HU, P = 0.75). Metastases of colorectal carcinoma (51.4+/-9.4 HU vs. 32.5+/-8.9 HU, P = 0.0001), malignant melanoma (56.1+/-6.4 HU vs. 34.2+/-1.6 HU, P = 0.0045), and thyroid cancer (53.5+/-15.5 HU vs. 15.7+/-4.2 HU, P = 0.001) showed a distinct wash-out, whereas metastases of lung cancer (23.1+/-6.3 HU vs. 58.6+/-4.8 HU, P = 0.001), salivary gland cancer (41.4+/-20.3 HU vs. 65.7+/-15.7 HU, P = 0.023), and sarcoma (56.2+/-7.4 HU vs. 90.2+/-3.4 HU, P = 0.001) had an increased enhancement in the delayed venous phase. The contrast enhancement behavior of pulmonary metastases can be evaluated with DECT and depends on the type of the primary malignant tumor. © The Foundation Acta Radiologica 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
    Acta Radiologica 04/2015; DOI:10.1177/0284185115582060 · 1.35 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1551125 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1551286 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1550911 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1550907 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1550909 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1551222 · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2015; 187(S 01). DOI:10.1055/s-0035-1551248 · 1.96 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To survey the perceived indications for magnetic resonance imaging of the small bowel (MRE) by experts, when MR enteroclysis (MREc) or MR enterography (MREg) may be chosen, and to determine how the approach to MRE is modified when general anaesthesia (GA) is required. Selected opinion leaders in MRE completed a questionnaire that included clinical indications (MREg or MREc), specifics regarding administration of enteral contrast, and how the technique is altered to accommodate GA. Fourteen responded. Only the diagnosis and follow-up of Crohn's disease were considered by over 80 % as a valid MRE indication. The remaining indications ranged between 35.7 % for diagnosis of caeliac disease and unknown sources of gastrointestinal bleeding to 78.6 % for motility disorders. The majority chose MREg over MREc for all indications (from 100 % for follow-up of caeliac disease to 57.7 % for tumour diagnosis). Fifty per cent of responders had needed to consider MRE under GA. The most commonly recommended procedural change was MRI without enteral distention. Three had experience with intubation under GA (MREc modification). Views were variable. Requests for MRE under GA are not uncommon. Presently most opinion leaders suggest standard abdominal MRI when GA is required. • Experts are using MRE for various indications. • Requests for MRE under general anaesthesia are not uncommon. • Some radiologists employ MREc under general anaesthesia; others do not distend the small bowel.
    04/2015; DOI:10.1007/s13244-015-0384-2
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Overall survival (OS) of patients with hepatic metastases of uveal melanoma is strongly linked with hepatic tumor control. Due to the lack of an effective systemic chemotherapy, locoregional therapies like radioembolization should play an increasingly important role. To report complications and response rates of radioembolization as salvage therapy for hepatic uveal melanoma metastases. Between October 2006 and January 2014, eight patients (age, 59.1 ± 15.3 years; 5 men) with histologically proven uveal melanoma and hepatic metastases received radioembolization with glass microspheres at a single center. All patients had been heavily pretreated with multiple systemic/locoregional therapies resulting in a long median interval between diagnosis of hepatic metastases and radioembolization (17.1 months; range, 6.4-23.2 months). Follow-up consisted of clinical assessment, laboratory tests and tri-phasic computed tomography (CT) before and 1, 3, 6, 9, and 12 months after radioembolization. Response to therapy was evaluated by CT using RECIST version 1.1 and by survival time. Safety (laboratory and clinical toxicity) was rated according to Common Terminology Criteria for Adverse Events 4.03. Using Kaplan-Meier analysis time to progression of hepatic metastases (hTTP) and OS were calculated. One month after radioembolization 50% of patients presented with stable and 50% with progressive disease. Median hTTP and OS after radioembolization were 4.3 weeks (range, 3.4-28.6 weeks) and 12.3 weeks (range, 3.7-62.6 weeks), respectively. Median OS after diagnosis of hepatic metastases was 19.9 months (range, 7.3-31.4 months). Radioembolization was tolerated well in all patients without toxicity higher than grade 2. Radioembolization is a safe salvage therapy even in heavily pretreated hepatic metastases of uveal melanoma.
    04/2015; 4(4):2047981615570417. DOI:10.1177/2047981615570417
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the usefulness of the metal artifact reduction technique "WARP" in the assessment of metal-on-metal hip resurfacings at 1.5 and 3T in the context of image quality and imaging speed. Nineteen patients (25 hip resurfacings) were randomized for 1.5 and 3T MRI, both including T1 and T2 turbo spin-echo as well as turbo inversion recovery magnitude sequences with and without view angle tilting and high bandwidth. Additional 3T sequences were acquired with a reduced number of averages and using the parallel acquisition technique for accelerating imaging speed. Artifact size (diameter, area), image quality (5-point scale) and delineation of anatomical structures were compared among the techniques, sequences and field strengths using the Wilcoxon sign-rank and paired t-test with Bonferroni correction. At both field strengths, WARP showed significant superiority over standard sequences regarding image quality, artifact size and delineation of anatomical structures. At 3T, artifacts were larger compared to 1.5T without affecting diagnostic quality, and scanning time could be reduced by up to 64 % without quality degradation. WARP proved useful in imaging metal-on-metal hip resurfacings at 1.5T as well as 3T with better image quality surrounding the implants. At 3T imaging could be considerably accelerated without losing diagnostic quality.
    Skeletal Radiology 03/2015; 44(7). DOI:10.1007/s00256-015-2128-2 · 1.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Assessment of motility alterations by functional magnetic resonance imaging (MRI) contributes to improved evaluation of inflammatory bowel disease. The aim of the study was to quantify motility in inflammatory bowel segments and to compare motility alterations with MR-based parameters for activity of inflammation in Crohn's disease (CD). Thirty consecutive patients with CD underwent bowel MRI which included a dynamic sequence for automatic generation of parametric maps facilitating quantification of bowel motility. Mean motility score (MMS) of small bowel segments with signs of inflammation was measured and compared with MMS of the whole gastrointestinal tract (GI tract). MRI-based score of inflammatory activity and lesion length were correlated with the MMS ratio of inflammatory small bowel lesion and whole GI tract. Inflammatory bowel segments showed a mean value of MMSs of 1080, whereas the whole GI tract showed a mean value of MMSs of 2839 (p < 0.0001). Decrease in motility ranged between 20 and 87% in inflammatory bowel segments compared to the MMS of the whole GI tract. The MMS ratio of an inflammatory small bowel segment and whole GI tract showed negative correlation with MR activity score (r = -0.5921, p = 0.0003) and length of the lesion (r = -0.3495, p = 0.0462). Quantitative assessment of motility alterations by means of motility scoring in small bowel segments affected by CD provides additional information on inflammatory activity. © 2015 John Wiley & Sons Ltd.
    Neurogastroenterology and Motility 03/2015; DOI:10.1111/nmo.12558 · 3.42 Impact Factor
  • S Kinner, M L Hahnemann, M Forsting, T C Lauenstein
    [Show abstract] [Hide abstract]
    ABSTRACT: Magnetic resonance imaging of the small bowel has been feasible for more than 15 years. This review is meant to give an overview of typical techniques, sequences and indications. Furthermore, newly evaluated promising techniques are presented, which have an impact on the advance of MR imaging of the small and large bowel. Key Points: • T2-weighted sequences both with and without fat saturation and T1-weighted fat saturated sequences prior to and following intravenous injection of a gadolinium-based contrast medium contitute the basics for bowel MR imaging.• Newer MR applications, such as diffusion-weighted imaging or contrast-enhaced dynamic sequences supply addtional information; they should thus be integrated in a regular sequence protocol für bowel MRI.• Additional new modalities like motility imaging and PET/MRI have to be evaluated in future studies. Citation Format: • Kinner S, Hahnemann ML, Forsting M et al. Magnetic Resonance Imaging of the Bowel: Today and Tomorrow. Fortschr Röntgenstr 2015; 187: 160 - 167. © Georg Thieme Verlag KG Stuttgart · New York.
    RöFo - Fortschritte auf dem Gebiet der R 03/2015; 187(3):160-167. DOI:10.1055/s-0034-1385453 · 1.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To develop and implement an automated algorithm for visualizing and quantifying bowel motility using cine magnetic resonance imaging (MRI). Four healthy volunteers as well as eight patients with suspected or diagnosed inflammatory bowel disease (IBD) underwent MR examinations on a 1.5T scanner. Coronal T2-weighted cine MR images were acquired in healthy volunteers without and with intravenous (i.v.) administration of butylscopolamine. In patients with IBD, cine MRI sequences were collected prior to standard bowel MRI. Bowel motility was assessed using an optical flow algorithm. The resulting motion vector magnitudes were presented as bowel motility maps. Motility changes after i.v. administration of butylscopolamine were measured in healthy volunteers. Inflamed bowel segments in patients were correlated with motility map findings. The acquisition of bowel motility maps was feasible in all subjects examined. In healthy volunteers butylscopolamine led to quantitatively measurable decrease in bowel motility (mean decrease of 59%; P = 0.171). In patients with IBD, visualization of bowel movement by color-coded motility mapping allowed for the detection of segments with abnormal bowel motility. Inflamed bowel segments could be identified by exhibiting a decreased motility. Our method is a feasible and promising approach for the assessment of bowel motility disorders. J. Magn. Reson. Imaging 2014. © 2014 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 02/2015; 41(2). DOI:10.1002/jmri.24557 · 2.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to assess the diagnostic benefit of diffusion-weighted imaging (DWI) in an (18)F-FDG PET/MR imaging protocol for whole-body staging of women with primary or recurrent malignancies of the pelvis. Forty-eight patients with a primary pelvic malignancy or suspected recurrence of a pelvic malignancy were included in our study. All patients underwent a whole-body (18)F-FDG PET/MR imaging examination that included DWI. Two radiologists separately evaluated the PET/MR imaging datasets without DWI followed by a second interpretation with DWI. First, both readers identified all primary tumors, as well as lymph node and distant metastases. In a second session, PET and DWI data were assessed qualitatively. Image interpretation comprised lesion conspicuity defined as visual lesion-to-background contrast (4-point ordinal scale) and diagnostic confidence (3-point ordinal scale) for all tumors. The results from histopathologic examination and cross-sectional imaging follow-up (≥6 mo) were used as the reference standard. Statistical analysis was performed to assess the significance of differences between obtained values. Among the 122 suspected lesions seen, 98 (80.3%) were considered malignant. PET/MR imaging without DWI had a sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of 92.9%, 87.5%, 96.8%, 75.0%, and 91.8%, respectively, for the detection of malignant lesions. PET/MR imaging with DWI had slightly higher values (94.9%, 83.3%, 95.9%, 80.0%, and 92.6%, respectively), but the difference was not significant (P > 0.05). In the qualitative assessment of lesion-to-background contrast, PET had significantly (P < 0.05) higher values (3.79 ± 0.58) than DWI (3.63 ± 0.77). Furthermore, significantly (P < 0.05) higher scores were found for diagnostic confidence using PET (2.68 ± 0.64) for the determination of malignant lesions, when compared with DWI (2.53 ± 0.69). DWI in PET/MR imaging has no diagnostic benefit for whole-body staging of women with pelvic malignancies. The omission of DWI for staging or restaging gynecologic cancer may significantly reduce examination times, thus increasing patient comfort without a relevant decrease in diagnostic competence. © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
    Journal of Nuclear Medicine 12/2014; 55(12):1930-5. DOI:10.2967/jnumed.114.146886 · 5.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background To evaluate the feasibility of 3 Tesla (T) high-resolution and gadolinium enhanced MRI of cartilage (dGEMRIC) in the thin and rounded hip cartilage of patients after acetabular matrix-based autologous chondrocyte transplantation (MACT).Methods Under general ethics approval, 24 patients were prospectively examined 6–31 months after acetabular MACT at 3T using high-resolution proton-density weighted (PDw) images (bilateral PD SPACE, 0.8 mm isotropic; unilateral PD-TSE coronal/sagittal, 0.8 × 0.8 resp. 0.5 × 0.5 × 2.5 mm) as well as T1 mapping (3D-FLASH, 0.78 mm isotropic) in dGEMRIC technique, and clinically scored. The cartilage transplant was evaluated using an adapted MOCART score (maximum 85 points). T1 relaxation times were measured independently by two radiologists. Here, regions of interest were placed manually in automatically calculated relaxation-maps, both in the transplant and adjacent healthy cartilage regions. Interobserver reliability was estimated by means of intraclass-correlation (ICC).ResultsThe transplant was morphologically definable in the PDw images of 23 patients with a mean MOCART score of 69 points (60–80 points, SD 6.5). T1 maps showed a clear differentiation between acetabular and femoral cartilage, but correlation with PDw images was necessary to identify the transplant. Mean T1 relaxation times of the transplant were 616.3 ms (observer 1) resp. 610.1 ms (observer 2), and of adjacent healthy acetabular cartilage 574.5 ms (observer 1) resp. 604.9 ms (observer 2). Interobserver reliability of the relaxation times in the transplant was excellent (ICC-coefficient 0.88) and in adjacent healthy regions good (0.77).Conclusion High-resolution PDw imaging with adapted MOCART scoring and dGEMRIC is feasible after MACT in the thin and rounded hip cartilage. J. Magn. Reson. Imaging 2014.
    Journal of Magnetic Resonance Imaging 12/2014; DOI:10.1002/jmri.24821 · 2.79 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: PurposeTo investigate whether additional diffusion-weighted imaging (DWI) improves therapy response evaluation by Gd-EOB magnetic resonance imaging (MRI) in hepatocellular carcinoma (HCC) after radioembolization.Materials and Methods Fifty patients with radioembolization for HCC underwent gadobutrol and Gd-EOB MRI with DWI prior to and 30, 90, and 180 days after radioembolization. A combination of gadobutrol MRI, alpha-fetoprotein, and imaging follow-up served as the reference standard. Two radiologists reviewed Gd-EOB alone (Gd-EOB), DWI alone (DWI), and the combination of both (Gd-EOB+DWI) separately and in consensus using a 4-point-scale: 1 = definitely no tumor progression (TP), 2 = probably no TP, 3 = probably TP, 4 = definitely TP. Receiver operating characteristic (ROC) and kappa analysis were performed.ResultsKappa values for Gd-EOB, DWI, and Gd-EOB+DWI ranged between 0.712 and 0.892 (P < 0.001). 30 days after radioembolization three out of 38 patients showed TP, which was missed by DWI in one case. No significant area under the curve (AUC) difference between Gd-EOB (1.0, P = 0.004), DWI (0.881, P = 0.030), and Gd-EOB+DWI (1.0, P = 0.004) was found (P = 0.320). 90 days after radioembolization six out of 28 patients showed TP, which was detected in one patient only by DWI and Gd-EOB+DWI. The AUC did not differ significantly (P = 0.319) between Gd-EOB (0.890, P = 0.004), DWI (1.0, P < 0.001), and Gd-EOB+DWI (1.0, P < 0.001). 180 days after radioembolization five patients showed TP, which in one case was missed by DWI. The AUC did not differ significantly (P1 = 0.322, P2 = 0.369, P3 = 0.350) between Gd-EOB (1.0, P = 0.003), DWI (0.913, P = 0.016), and Gd-EOB+DWI (0.963, P = 0.007).Conclusion Additional DWI does not substantially improve therapy response evaluation by Gd-EOB MRI in HCC after radioembolization but proved helpful in single cases. J. Magn. Reson. Imaging 2014.
    Journal of Magnetic Resonance Imaging 12/2014; DOI:10.1002/jmri.24827 · 2.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Depiction of the exact arterial liver anatomy as well as identifying potential extrahepatic non-target vessels is crucial for a successful preparation of radioembolization (RE).
    Acta Radiologica 11/2014; DOI:10.1177/0284185114558973 · 1.35 Impact Factor

Publication Stats

3k Citations
717.87 Total Impact Points

Institutions

  • 2001–2015
    • University Hospital Essen
      • Institute of Diagnostic and Interventional Radiology and Neuroradiology
      Essen, North Rhine-Westphalia, Germany
  • 2003–2014
    • University of Duisburg-Essen
      • • Erwin L. Hahn Institute for Magnetic Resonance Imaging
      • • Faculty of Medicine
      Essen, North Rhine-Westphalia, Germany
  • 2013
    • Heinrich-Heine-Universität Düsseldorf
      • Institute of Diagnostic and interventional radiology
      Düsseldorf, North Rhine-Westphalia, Germany
    • Huazhong University of Science and Technology
      • Department of Infectious Diseases
      Wu-han-shih, Hubei, China
  • 2007–2008
    • Emory University
      • Department of Radiology and Imaging Sciences
      Atlanta, Georgia, United States
  • 2006
    • University of Hamburg
      • Medical Prevention Center Hamburg (MPCH)
      Hamburg, Hamburg, Germany