Sven Zuehlsdorff

The Ohio State University, Columbus, Ohio, United States

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Publications (103)296.46 Total impact

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    ABSTRACT: PURPOSE: To describe and characterize a new approach to first-pass myocardial perfusion utilizing balanced steady-state free precession acquisition without the use of saturation recovery or other magnetization preparation. THEORY: The balanced steady-state free precession sequence is inherently sensitive to contrast agent enhancement of the myocardium. This sensitivity can be used to advantage in first-pass myocardial perfusion imaging by eliminating the need for magnetization preparation. METHODS: Bloch equation simulations, phantom experiments, and in vivo 2D imaging studies were run comparing the proposed technique with three other methods: saturation recovery spoiled gradient echo, saturation recovery steady-state free precession, and steady-state spoiled gradient echo without magnetization preparation. Additionally, an acquisition-reconstruction strategy for 3D perfusion imaging is proposed and initial experience with this approach is demonstrated in healthy subjects and one patient. RESULTS: Phantom experiments verified simulation results showing the sensitivity of the balanced steady-state free precession sequence to contrast agent enhancement in solid tissue is similar to that of magnetization-prepared acquisitions. Images acquired in normal volunteers showed the proposed technique provided superior signal and signal-to-noise ratio compared with all other sequences at baseline as well as postcontrast. CONCLUSIONS: A new approach to first-pass myocardial perfusion is presented that obviates the need for magnetization preparation and provides high signal-to-noise ratio. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 02/2013; · 3.27 Impact Factor
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    ABSTRACT: PURPOSE: To evaluate the feasibility of free-breathing three-dimensional (3D) phase sensitive inversion recovery (PSIR) Turbo FLASH late gadolinium enhancement (LGE) magnetic resonance images (MRI) on left ventricular scar in patients with coronary artery disease (CAD) compared with clinically established breathhold two-dimensional (2D) PSIR Turbo FLASH images. MATERIALS AND METHODS: In 58 consecutive patients with confirmed CAD, LGE MRI using the two sequences have been acquired. Image quality was graded on a four-point scale according to the image appearance. Qualitative evaluation including the distribution area and the transmural extent of the scar based on the American Heart Association's (AHA's) 17-segment model was performed in both of 2D and 3D images. The scar volumes were compared quantitatively between 2D and 3D images. RESULTS: A total of 51 individuals were used for final statistical analysis. No differences were noted in image quality (P = 0.80), scar distribution area (P = 0.17), and scar transmural extent (P = 0.20) between 3D and 2D images. There was strong correlation in scar volume between the 3D and 2D results (r = 0.940; P < 0.001; Y = 0.298 + 1.251X, R(2) = 0.876). But the scar volume derived from 3D images was significantly larger than that derived from 2D images (2D versus 3D, 20.08 ± 9.41 cm(3) versus 25.41 ± 12.57 cm(3) , t = -7.60; P < 0.001). The trend toward a larger scar volume identified by 3D method was indicated through Bland-Altman analysis. CONCLUSION: Free-breathing 3D PSIR Turbo FLASH imaging is another feasible method to identify left ventricular myocardial scar in patients with CAD and detects more scar volume compared with breathhold 2D PSIR Turbo FLASH imaging. J. Magn. Reson. Imaging 2012;. © 2012 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 12/2012; · 2.57 Impact Factor
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    ABSTRACT: Magnetic resonance elastography (MRE) can noninvasively measure the stiffness of liver tissue and display this information in anatomic maps. Magnetic resonance imaging (MRI) guidance has not previously been used to biopsy segments of heterogeneous stiffness identified on MRE. Dedicated study of MRE in post-liver transplant patients is also limited. In this study, the ability of real-time MRI to guide biopsies of segments of the liver with different MRE stiffness values in the same post-transplant patient was assessed. MRE was performed in 9 consecutive posttransplant patients with history of hepatitis C. Segments of highest and lower stiffness on MRE served as targets for subsequent real-time MRI-guided biopsy using T2-weighted imaging. The ability of MRI-guided biopsy to successfully obtain tissue specimens was assessed. The Wilcoxon signed-rank test was used to compare mean stiffness differences for highest and lower MRE stiffness segments, with α = 0.05. MRI guidance allowed successful sampling of liver tissue for all (18/18) biopsies. There was a statistically significant difference in mean MRE stiffness values between highest (4.61 ± 1.99 kPa) and lower stiffness (3.03 ± 1.75 kPa) (P = .0039) segments biopsied in the 9 posttransplant patients. Real-time MRI can guide biopsy in patients after liver transplantation based on MRE stiffness values. This study supports the use of MRI guidance to sample tissue based on functional information.
    Academic radiology 09/2012; 19(9):1121-6. · 2.09 Impact Factor
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    ABSTRACT: The assessment of myocardial fibrosis and extracellular volume requires accurate estimation of myocardial T(1) s. While image acquisition using the modified Look-Locker inversion recovery technique is clinically feasible for myocardial T(1) mapping, respiratory motion can limit its applicability. Moreover, the conventional T(1) fitting approach using the magnitude inversion recovery images can lead to less stable T(1) estimates and increased computational cost. In this article, we propose a novel T(1) mapping scheme that is based on phase-sensitive image reconstruction and the restoration of polarity of the MR signal after inversion. The motion correction is achieved by registering the reconstructed images after background phase removal. The restored signal polarity of the inversion recovery signal helps the T(1) fitting resulting in improved quality of the T(1) map and reducing the computational cost. Quantitative validation on a data cohort of 45 patients proves the robustness of the proposed method against varying image contrast. Compared to the magnitude T(1) fitting, the proposed phase-sensitive method leads to less fluctuation in T(1) estimates. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 06/2012; · 3.27 Impact Factor
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    ABSTRACT: Example of improved T1 mapping after motion correction. Left column: T1 maps of original modified Look-Locker inversion recovery (MOLLI) sequence images indicating smearing on the myocardium due to imperfect breath-holding. Right column: Sharp myocardial boundary is recovered after motion correction using proposed technique. These images were from three different patients from the article by Xue et al (pp 1644-1655).
    Magnetic Resonance in Medicine 06/2012; 67(6):spcone. · 3.27 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:P177. · 4.44 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:P251. · 4.44 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:P253. · 4.44 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:P249. · 4.44 Impact Factor
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    Zhaoyang Fan, Sven Zuehlsdorff, Xin Liu, Debiao Li
    Journal of Cardiovascular Magnetic Resonance 02/2012; 14 Suppl 1:O44. · 4.44 Impact Factor
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    ABSTRACT: Quantitative T(2) mapping was recently shown to be superior to T(2) -weighted imaging in detecting T(2) changes across myocardium. Pixel-wise T(2) mapping is sensitive to misregistration between the images used to generate the parameter map. In this study, utility of two motion-compensation strategies-(i) navigator gating with prospective slice correction and (ii) nonrigid registration-was investigated for myocardial T(2) mapping in short axis and horizontal long axis views. Navigator gating provides respiratory motion compensation, whereas registration corrects for residual cardiac and respiratory motion between images; thus, the two strategies provided complementary functions. When these were combined, respiratory-motion-induced T(2) variability, as measured by both standard deviation and interquartile range, was comparable to that in breath-hold T(2) maps. In normal subjects, this combined motion-compensation strategy increased the percentage of myocardium with T(2) measured to be within normal range from 60.1% to 92.2% in short axis and 62.3% to 92.7% in horizontal long axis. The new motion-compensated T(2) mapping technique, which combines navigator gating, prospective slice correction, and nonrigid registration to provide through-plane and in-plane motion correction, enables a method for fully automatic and robust free-breathing T(2) mapping. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 01/2012; 68(5):1570-8. · 3.27 Impact Factor
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    Zhaoyang Fan, Sven Zuehlsdorff, Xin Liu, Debiao Li
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    ABSTRACT: Three-dimensional black-blood MRI is a promising noninvasive imaging technique for the assessment of atherosclerotic carotid artery disease. However, this technique is inherently susceptible to motion. In particular, swallowing can result in considerable wall motion at the carotid bifurcations, which may induce drastic image degradation or substantial overestimation of wall thickness. Self-gating techniques have previously been shown to be capable of resolving and compensating for cardiac or respiratory motion during MRI. This work presents a self-gating-based prospective motion gating scheme that is combined with a three-dimensional variable-flip-angle turbo spin-echo sequence (SPACE) for detecting swallowing motion. Self-gating signal readouts along the superior-inferior direction during each repetition time period are used to derive the projection profiles of the imaging volume. Based on cross-correlation analysis between the projection profiles and the corresponding reference profiles, swallowing motion can be detected and the motion-contaminated data will subsequently be discarded and reacquired in the next repetition time. The self-gated SPACE sequence was validated on eight healthy volunteers and two patients and, when compared with the conventional SPACE sequence, proved to be more resistant to swallowing motion and significantly improved image quality as well as the sharpness of carotid artery wall boundaries.
    Magnetic Resonance in Medicine 12/2011; 67(2):490-8. · 3.27 Impact Factor
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    ABSTRACT: PURPOSE The purpose of the study is to evaluate a fully automated motion corrected first pass myocardial perfusion (FPMP) MRI with semi quantitative perfusion parameter maps in patients with suspected ischemic heart disease. METHOD AND MATERIALS A recently introduced framework to automatically analyze cardiac first pass perfusion MR includes registration, surface coil correction and noise suppression of images as well as pixel by pixel based map generation of semi-quantitative parameters. Stress and rest FPMP images were acquired in 28 patients with suspected ischemic heart disease on 1.5T scanner (MAGNETOM Avanto, Siemens Healthcare). Three short axis slices were acquired during infusion of 0.075 mMol/kg of Gadolinium (Magnevist, Bayer HealthCare Pharmaceuticals, USA) at rate of 4 ml/sec and adenosine (Adenoscan, Astellas Pharma, USA) infusion (0.14 mg/kg/min; duration: 4 min) were administrated to induce stress. Free breathing, motion-corrected images and corresponding perfusion maps were assessed independently by 2 radiologists using the AHA 16 model and evaluated using a four point Likert scale (poor to excellent) to evaluate image quality and confidence level in presence or absence of hypo-perfusion regions. Upslope index of both free breathing and motion corrected images during stress and rest were manually calculated in non-ischemic and ischemic areas and compared to the corresponding pixel wise parameter map generated based on motion corrected images. FPMP MRI results were subsequently compared to coronary angiogram, stress echocardiography, or SPECT. RESULTS All patients were successfully scanned; perfusion defects were detected in 18 patients. The mean image quality score for motion corrected images (3.57 ± 0.42) and confidence level (3.28 ± 0.51) were significantly higher (p<0.001), than free breathing images (mean image score of 2.5 ± 0.62 and confidence level of 2.94 ± 0.39). Upslope index of non ischemic and ischemic areas and semi quantitative perfusion parameter maps values were comparable. CONCLUSION The feasibility of a fully integrated semi-quantitative myocardial perfusion analysis was demonstrated in patients with myocardial ischemia. CLINICAL RELEVANCE/APPLICATION A fully automated motion corrected first pass myocardial perfusion MRI with semi quantitative perfusion parameter maps is a feasible approach for evaluation of patients with myocardial ischemia.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
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    ABSTRACT: To compare different state-of-the-art T2-weighted (T2w) imaging sequences combined with late gadolinium enhancement (LGE) for myocardial salvage area (MSA) assessment by cardiac magnetic resonance (CMR). T2w imaging has been used to assess the myocardial area at risk (AAR) in acute myocardial infarction (AMI) patients, but its clinical application is challenging due to technical and physical limitations. Thirty patients with reperfused AMI underwent complete CMR imaging 2-5 days after hospital admission. Myocardial AAR and MSA were quantified on four different T2w sequences: (a) free-breathing T2-prepared single-shot balanced steady-state free precession (T2p_ssbSSFP); (b) breathhold T2-weighted acquisition for cardiac unified T2 edema (ACUTE); (c) breathhold T2w dark-blood inversion recovery turbo-spin echo (IR-TSE) (short-term inversion recovery: STIR); and (d) free-breathing high-resolution T2 dark-blood navigated BLADE. The diagnostic performance of each technique was also assessed. Quantitative analysis showed significant differences in myocardial AAR extent as quantified by the four T2w sequences (P < 0.05). There were also significant differences in sensitivity, specificity and overall diagnostic performance. Detection and quantification of AAR, and thus of MSA, by T2wCMR in reperfused AMI patients varied significantly between different T2w sequences in the same clinical setting.
    Journal of Magnetic Resonance Imaging 09/2011; 35(2):328-39. · 2.57 Impact Factor
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    ABSTRACT: Quantification of myocardial T1 relaxation has potential value in the diagnosis of both ischemic and nonischemic cardiomyopathies. Image acquisition using the modified Look-Locker inversion recovery technique is clinically feasible for T1 mapping. However, respiratory motion limits its applicability and degrades the accuracy of T1 estimation. The robust registration of acquired inversion recovery images is particularly challenging due to the large changes in image contrast, especially for those images acquired near the signal null point of the inversion recovery and other inversion times for which there is little tissue contrast. In this article, we propose a novel motion correction algorithm. This approach is based on estimating synthetic images presenting contrast changes similar to the acquired images. The estimation of synthetic images is formulated as a variational energy minimization problem. Validation on a consecutive patient data cohort shows that this strategy can perform robust nonrigid registration to align inversion recovery images experiencing significant motion and lead to suppression of motion induced artifacts in the T1 map.
    Magnetic Resonance in Medicine 08/2011; 67(6):1644-55. · 3.27 Impact Factor
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    ABSTRACT: The aim of this study was to develop a targeted volumetric radiofrequency field (B(1)(+)) mapping technique to provide region-of-interest B(1)(+) information. Targeted B(1)(+) maps were acquired using three-dimensional (3D) reduced field-of-view (FOV) inner-volume turbo spin echo-catalyzed double-angle method (DAM). Targeted B(1)(+) maps were compared with full-FOV B(1)(+) maps acquired using 3D catalyzed DAM in a phantom and in the brain of a healthy volunteer. In addition, targeted volumetric abdomeninal B(1)(+) mapping was demonstrated in the abdomen of another healthy volunteer. The targeted reduced-FOV images demonstrated no aliasing artifacts in all experiments. Close match between targeted B(1)(+) map and reference full-FOV B(1)(+) map in the same region was observed, with percentage root-mean-squared error <0.4% in the phantom and <0.8% in the healthy volunteer brain. The abdominal B(1)(+) maps showed small B(1)(+) variation in the kidneys and liver from the healthy volunteer. The proposed 3D reduced-FOV catalyzed DAM provides a rapid, simple and accurate method for targeted volumetric B(1)(+) mapping and can be easily implemented for applications related to radiofrequency field mapping in small targeted regions.
    Magnetic Resonance Imaging 06/2011; 29(8):1131-7. · 2.06 Impact Factor
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    ABSTRACT: The navigator gating and slice tracking approach currently used for respiratory motion compensation during free-breathing coronary magnetic resonance angiography (MRA) has low imaging efficiency (typically 30-50%), resulting in long imaging times. In this work, a novel respiratory motion correction technique with 100% scan efficiency was developed for free-breathing whole-heart coronary MRA. The navigator signal was used as a reference respiratory signal to segment the data into six bins. 3D projection reconstruction k-space sampling was used for data acquisition and enabled reconstruction of low resolution images within each respiratory bin. The motion between bins was estimated by image registration with a 3D affine transform. The data from the different respiratory bins was retrospectively combined after motion correction to produce the final image. The proposed method was compared with a traditional navigator gating approach in nine healthy subjects. The proposed technique acquired whole-heart coronary MRA with 1.0 mm(3) isotropic spatial resolution in a scan time of 6.8 ± 0.9 min, compared with 16.2 ± 2.8 min for the navigator gating approach. The image quality scores, and length, diameter and sharpness of the right coronary artery (RCA), left anterior descending coronary artery (LAD), and left circumflex coronary artery (LCX) were similar for both approaches (P > 0.05 for all), but the proposed technique reduced scan time by a factor of 2.5.
    Magnetic Resonance in Medicine 05/2011; 65(5):1269-77. · 3.27 Impact Factor
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    ABSTRACT: To investigate the contribution of proton density (PD) in T(2) -STIR based edema imaging in the setting of acute myocardial infarction (AMI). Canines (n = 5), subjected to full occlusion of the left anterior descending artery for 3 hours, underwent serial magnetic resonance imaging (MRI) studies 2 hours postreperfusion (day 0) and on day 2. During each study, T(1) and T(2) maps, STIR (TE = 7.1 msec and 64 msec) and late gadolinium enhancement (LGE) images were acquired. Using T(1) and T(2) maps, relaxation and PD contributions to myocardial edema contrast (EC) in STIR images at both TEs were calculated. Edematous territories showed significant increase in PD (20.3 ± 14.3%, P < 0.05) relative to healthy territories. The contributions of T(1) changes and T(2) or PD changes toward EC were in opposite directions. One-tailed t-test confirmed that the mean T(2) and PD-based EC at both TEs were greater than zero. EC from STIR images at TE = 7.1 msec was dominated by PD than T(2) effects (94.3 ± 11.3% vs. 17.6 ± 2.5%, P < 0.05), while at TE = 64 msec, T(2) effects were significantly greater than PD effects (90.8 ± 20.3% vs. 12.5 ± 11.9%, P < 0.05). The contribution from PD in standard STIR acquisitions (TE = 64 msec) was significantly higher than 0 (P < 0.05). In addition to T(2) -weighting, edema detection in the setting of AMI with T(2) -weighted STIR imaging has a substantial contribution from PD changes, likely stemming from increased free-water content within the affected tissue. This suggests that imaging approaches that take advantage of both PD as well as T(2) effects may provide the optimal sensitivity for detecting myocardial edema.
    Journal of Magnetic Resonance Imaging 04/2011; 33(4):962-7. · 2.57 Impact Factor
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    ABSTRACT: We assessed the hypothesis that black-blood steady-state free precession (SSFP) would provide coronary wall images comparable to images from TSE and have better performance than TSE under conditions of fast heart rate. With IRB approval, thirty participants without a history of coronary artery disease (19 men, 11 women, 26-83 y/o) were scanned with a 1.5 T MR scanner. Cross-sectional black-blood images of the proximal portions of coronary arteries were acquired with a two-dimensional (2D), double inversion recovery (DIR) prepared TSE sequence and a 2D DIR SSFP sequence on the same planes. Image quality (ranked with a 4-point system, scored from 0 to 3), vessel wall area and thickness, signal-to-noise ratio (SNR) of the wall and contrast-to-noise ratio (CNR, wall to lumen) were compared between SSFP and TSE with SPSS software (v 13.0). Totally 28 scans were completed. For SSFP and TSE, there was no difference in image quality. SSFP had a higher SNR (23.7 ± 10.1 vs. 14.4 ± 5.2, P < 0.001) and wall-lumen CNR (8.8 ± 4.5 vs. 6.7 ± 3.2, P = 0.001). Good agreements between measured wall area (r = 0.701, P < 0.001) and thickness (r = 0.560, P < 0.001) were found. For 10 participants with heart rate more than 80 beats/min, the image quality of SSFP was higher than TSE (P = 0.016). SSFP provided image quality and measurement accuracy that was comparable to TSE. With its higher performance under fast heart rate conditions, SSFP may break through the existing thresholds for heart rate and extend clinical applicability of coronary wall MR imaging to a larger population.
    The international journal of cardiovascular imaging 04/2011; 28(3):567-75. · 2.15 Impact Factor
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    ABSTRACT: Cardiac perfusion magnetic resonance imaging (MRI) has proven clinical significance in diagnosis of heart diseases. However, analysis of perfusion data is time-consuming, where automatic detection of anatomic landmarks and key-frames from perfusion MR sequences is helpful for anchoring structures and functional analysis of the heart, leading toward fully automated perfusion analysis. Learning-based object detection methods have demonstrated their capabilities to handle large variations of the object by exploring a local region, i.e., context. Conventional 2D approaches take into account spatial context only. Temporal signals in perfusion data present a strong cue for anchoring. We propose a joint context model to encode both spatial and temporal evidence. In addition, our spatial context is constructed not only based on the landmark of interest, but also the landmarks that are correlated in the neighboring anatomies. A discriminative model is learned through a probabilistic boosting tree. A marginal space learning strategy is applied to efficiently learn and search in a high dimensional parameter space. A fully automatic system is developed to simultaneously detect anatomic landmarks and key frames in both RV and LV from perfusion sequences. The proposed approach was evaluated on a database of 373 cardiac perfusion MRI sequences from 77 patients. Experimental results of a 4-fold cross validation show superior landmark detection accuracies of the proposed joint spatial-temporal approach to the 2D approach that is based on spatial context only. The key-frame identification results are promising.
    Society of Photo-Optical Instrumentation Engineers (SPIE); 03/2011

Publication Stats

506 Citations
296.46 Total Impact Points

Institutions

  • 2012–2013
    • The Ohio State University
      Columbus, Ohio, United States
    • Northwestern Memorial Hospital
      Chicago, Illinois, United States
    • Cedars-Sinai Medical Center
      • Cedars Sinai Medical Center
      Los Angeles, California, United States
  • 2006–2013
    • University of Illinois at Chicago
      Chicago, Illinois, United States
  • 2009–2012
    • Siemens
      München, Bavaria, Germany
    • Northwestern University
      • Department of Radiology
      Evanston, Illinois, United States
    • National Heart, Lung, and Blood Institute
      Maryland, United States
  • 2011
    • Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center
      Torrance, California, United States
    • University of California, Los Angeles
      • Department of Bioengineering
      Los Angeles, California, United States
  • 2003–2006
    • German Cancer Research Center
      • Division of Medical Physics in Radiology
      Heidelberg, Baden-Wuerttemberg, Germany