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Voit D, Kalentev O, van Zalk M, Joseph AA, Frahm J. Rapid and motion-robust volume coverage using cross-sectional real-time MRI. Magn Reson Med 2019; 83:1652-1658. [PMID: 31670850 DOI: 10.1002/mrm.28029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/13/2019] [Accepted: 09/13/2019] [Indexed: 01/29/2023]
Abstract
PURPOSE To develop a rapid and motion-robust technique for volumetric MRI, which is based on cross-sectional real-time MRI acquisitions with automatic advancement of the slice position. METHODS Real-time MRI with a frame-by-frame moving cross-section is performed with use of highly undersampled radial gradient-echo sequences offering spin density, T1 , or T2 /T1 contrast. Joint reconstructions of serial images and coil sensitivity maps from spatially overlapping sections are accomplished by nonlinear inversion with regularization to the preceding section-formally identical to dynamic real-time MRI. Shifting each frame by 20% to 25% of the section thickness ensures 75% to 80% overlap of successive sections. Acquisition times of 40 to 67 ms allow for rates of 15 to 25 sections per second, while volumes are defined by the number of cross-sections times the section shift. RESULTS Preliminary realizations at 3T comprise studies of the human brain, carotid arteries, liver, and prostate. Typically, coverage of a 90- to 180-mm volume at 0.8- to 1.2-mm in-plane resolution, 4- to 6-mm section thickness, and 0.8- to 1.5-mm section shift is accomplished within total measuring times of 4 to 6 seconds and a section speed of 15 to 37.5 mm per second. However, spatiotemporal resolution, contrast including options such as fat saturation and total measuring time are highly variable and may be adjusted to clinical needs. Promising volumetric applications range from fetal MRI to dynamic contrast-enhanced MRI. CONCLUSION The proposed method allows for rapid and motion-robust volume coverage in a variety of imaging scenarios.
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Affiliation(s)
- Dirk Voit
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Oleksandr Kalentev
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Maaike van Zalk
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
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Walker A, Liney G, Holloway L, Dowling J, Rivest-Henault D, Metcalfe P. Continuous table acquisition MRI for radiotherapy treatment planning: distortion assessment with a new extended 3D volumetric phantom. Med Phys 2015; 42:1982-91. [PMID: 25832089 DOI: 10.1118/1.4915920] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Accurate geometry is required for radiotherapy treatment planning (RTP). When considering the use of magnetic resonance imaging (MRI) for RTP, geometric distortions observed in the acquired images should be considered. While scanner technology and vendor supplied correction algorithms provide some correction, large distortions are still present in images, even when considering considerably smaller scan lengths than those typically acquired with CT in conventional RTP. This study investigates MRI acquisition with a moving table compared with static scans for potential geometric benefits for RTP. METHODS A full field of view (FOV) phantom (diameter 500 mm; length 513 mm) was developed for measuring geometric distortions in MR images over volumes pertinent to RTP. The phantom consisted of layers of refined plastic within which vitamin E capsules were inserted. The phantom was scanned on CT to provide the geometric gold standard and on MRI, with differences in capsule location determining the distortion. MRI images were acquired with two techniques. For the first method, standard static table acquisitions were considered. Both 2D and 3D acquisition techniques were investigated. With the second technique, images were acquired with a moving table. The same sequence was acquired with a static table and then with table speeds of 1.1 mm/s and 2 mm/s. All of the MR images acquired were registered to the CT dataset using a deformable B-spline registration with the resulting deformation fields providing the distortion information for each acquisition. RESULTS MR images acquired with the moving table enabled imaging of the whole phantom length while images acquired with a static table were only able to image 50%-70% of the phantom length of 513 mm. Maximum distortion values were reduced across a larger volume when imaging with a moving table. Increased table speed resulted in a larger contribution of distortion from gradient nonlinearities in the through-plane direction and an increased blurring of capsule images, resulting in an apparent capsule volume increase by up to 170% in extreme axial FOV regions. Blurring increased with table speed and in the central regions of the phantom, geometric distortion was less for static table acquisitions compared to a table speed of 2 mm/s over the same volume. Overall, the best geometric accuracy was achieved with a table speed of 1.1 mm/s. CONCLUSIONS The phantom designed enables full FOV imaging for distortion assessment for the purposes of RTP. MRI acquisition with a moving table extends the imaging volume in the z direction with reduced distortions which could be useful particularly if considering MR-only planning. If utilizing MR images to provide additional soft tissue information to the planning CT, standard acquisition sequences over a smaller volume would avoid introducing additional blurring or distortions from the through-plane table movement.
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Affiliation(s)
- Amy Walker
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia and Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Gary Liney
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia; and South West Clinical School, University of New South Wales, Sydney, NSW 2170, Australia
| | - Lois Holloway
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia; Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia; South West Clinical School, University of New South Wales, Sydney, NSW 2170, Australia; and Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW 2006, Australia
| | - Jason Dowling
- Commonwealth Scientific and Industrial Research Organisation, Australian E-Health Research Centre, Herston, QLD 4029, Australia
| | - David Rivest-Henault
- Commonwealth Scientific and Industrial Research Organisation, Australian E-Health Research Centre, Herston, QLD 4029, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia and Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
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Mosavi F, Laurell A, Ahlström H. Whole body MRI, including diffusion-weighted imaging in follow-up of patients with testicular cancer. Acta Oncol 2015; 54:1763-9. [PMID: 25975210 DOI: 10.3109/0284186x.2015.1043027] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Whole body (WB) magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI) has become increasingly utilized in cancer imaging, yet the clinical utility of these techniques in follow-up of testicular cancer patients has not been evaluated. The purpose of this study was to evaluate the feasibility of WB MRI with continuous table movement (CTM) technique, including multistep DWI in follow-up of patients with testicular cancer. PATIENTS AND METHODS WB MRI including DWI was performed in follow-up of 71 consecutive patients (median age, 37 years; range 19-84) with histologically confirmed testicular cancer. WB MRI protocol included axial T1-Dixon and T2-BLADE sequences using CTM technique. Furthermore, multi-step DWI was performed using b-value 50 and 1000 s/mm(2). One criterion for feasibility was patient tolerance and satisfactory image quality. Another criterion was the accuracy in detection of any pathological mass, compared to standard of reference. Signal intensity in DWI was used for evaluation of residual mass activity. Clinical, laboratory and imaging follow-up were applied as standard of reference for the evaluation of WB MRI. RESULTS WB MRI was tolerated in nearly all patients (69/71 patients, 97%) and the image quality was satisfactory. Metal artifacts deteriorated the image quality in six patients, but it did not influence the overall results. No case of clinical relapse was observed during the follow-up time. There was a good agreement between conventional WB MRI and standard of reference in all patients. Three patients showed residual masses and DWI signal was not restricted in these patients. Furthermore, DWI showed abnormally high signal intensity in a normal-sized retroperitoneal lymph node indicating metastasis. The subsequent (18)F-FDG PET/CT could verify the finding. CONCLUSION WB MRI with CTM technique including multi-step DWI is feasible in follow-up of patients with testicular cancer. DWI may contribute to important added-value data to conventional MRI sequences regarding the activity of residual masses.
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Affiliation(s)
- Firas Mosavi
- a Section of Radiology, Department of Radiology , Oncology and Radiation Science, Uppsala University Hospital , Uppsala , Sweden
| | - Anna Laurell
- b Section of Oncology, Department of Radiology , Oncology and Radiation Science, Uppsala University Hospital , Uppsala , Sweden
| | - Håkan Ahlström
- a Section of Radiology, Department of Radiology , Oncology and Radiation Science, Uppsala University Hospital , Uppsala , Sweden
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Ludwig UA, Klausmann F, Baumann S, Honal M, Hövener JB, König D, Deibert P, Büchert M. Whole-body MRI-based fat quantification: a comparison to air displacement plethysmography. J Magn Reson Imaging 2014; 40:1437-44. [PMID: 24449401 DOI: 10.1002/jmri.24509] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 10/14/2013] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To demonstrate the feasibility of an algorithm for MRI whole-body quantification of internal and subcutaneous fat and quantitative comparison of total adipose tissue to air displacement plethysmography (ADP). MATERIALS AND METHODS For comparison with ADP, whole-body MR data of 11 volunteers were obtained using a continuously moving table Dixon sequence. Resulting fat images were corrected for B1 related intensity inhomogeneities before fat segmentation. RESULTS The performed MR measurements of the whole body provided a direct comparison to ADP measurements. The segmentation of subcutaneous and internal fat in the abdomen worked reliably with an accuracy of 98%. Depending on the underlying model for fat quantification, the resultant MR fat masses represent an upper and a lower limit for the true fat masses. In comparison to ADP, the results were in good agreement with ρ ≥ 0.97, P < 0.0001. CONCLUSION Whole-body fat quantities derived noninvasively by using a continuously moving table Dixon acquisition were directly compared with ADP. The accuracy of the method and the high reproducibility of results indicate its potential for clinical applications.
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Affiliation(s)
- Ute A Ludwig
- Department of Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany
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Braun H, Ziegler S, Lentschig MG, Quick HH. Implementation and Performance Evaluation of Simultaneous PET/MR Whole-Body Imaging with Continuous Table Motion. J Nucl Med 2013; 55:161-8. [DOI: 10.2967/jnumed.113.123372] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Xing XH, Cheng YS. Magnetic resonance functional and molecular imaging for diagnosis of rectal cancer: Recent research advances. Shijie Huaren Xiaohua Zazhi 2013; 21:1726-1732. [DOI: 10.11569/wcjd.v21.i18.1726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer is one of the most common gastrointestinal malignant tumors in China. Because of the difficulties in early diagnosis, the incidence and mortality of colorectal cancer have been increasing year by year. Molecular and functional imaging plays an important role in detecting rectal cancer earlier and more specifically and reducing patients' mortality. In this paper we discuss the present and future applications of magnetic resonance molecular and functional imaging in the diagnosis of rectal tumors.
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Baumann T, Kannengiesser SAR, Honal M. Temporally constrained respiratory gating improves continuously moving table MRI during free breathing. J Magn Reson Imaging 2012; 38:198-205. [PMID: 23239532 DOI: 10.1002/jmri.23964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 10/23/2012] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To evaluate a novel breathing motion correction algorithm for continuously moving table magnetic resonance imaging (CMT-MRI) that optimizes motion consistency in a fixed time span. MATERIALS AND METHODS In 22 patients CMT-MRI was performed during free breathing. During a preparatory phase (constant) or continuously during the scan (adaptive) gating thresholds were computed from breathing states that should allow for motion consistent k-space sampling. After data from a first k-space traversal was acquired irrespective of breathing motion, subsequently k-space lines with discordant breathing states were reacquired below the gating threshold. Time constraints of CMT-MRI were respected, because a fixed time was allocated for reacquisition. Image quality and lesion depiction were evaluated on images reconstructed from the first traversal and motion-corrected images. RESULTS Compared to constant thresholds, gating with adaptive thresholds led to a higher number of reacquired k-space lines (60.1%/41.7%) and a larger fraction of motion consistent final k-space lines (96.6%/78.8%). Adaptive gating induced a significant increase in image quality for all regions affected by breathing motion. Only one of 22 lesions was not depicted on the adaptively corrected images, whereas 15 were readily appreciable. CONCLUSION Temporally constrained respiratory gating with adaptive thresholds allows for fully sampled, motion-corrected CMT-MRI acquisitions during free breathing.
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Affiliation(s)
- Tobias Baumann
- Department of Diagnostic Radiology, University Hospital Freiburg, Germany.
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Blumhagen JO, Ladebeck R, Fenchel M, Scheffler K. MR-based field-of-view extension in MR/PET:B0homogenization using gradient enhancement (HUGE). Magn Reson Med 2012. [DOI: 10.1002/mrm.24555] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jan O. Blumhagen
- Magnetic Resonance; Healthcare Sector; Siemens AG; Erlangen Germany
- Division of Radiological Physics; University of Basel Hospital; Basel Switzerland
| | - Ralf Ladebeck
- Magnetic Resonance; Healthcare Sector; Siemens AG; Erlangen Germany
| | - Matthias Fenchel
- Magnetic Resonance; Healthcare Sector; Siemens AG; Erlangen Germany
| | - Klaus Scheffler
- Division of Radiological Physics; University of Basel Hospital; Basel Switzerland
- MRC Department; Max Planck Institute for Biological Cybernetics; Tuebingen Germany
- Department of Biomedical Magnetic Resonance; University Hospital Tuebingen; Tuebingen Germany
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Braun H, Ziegler S, Paulus DH, Quick HH. Hybrid PET/MRI imaging with continuous table motion. Med Phys 2012; 39:2735-45. [DOI: 10.1118/1.4704726] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Weckbach S, Michaely HJ, Stemmer A, Schoenberg SO, Dinter DJ. Comparison of a new whole-body continuous-table-movement protocol versus a standard whole-body MR protocol for the assessment of multiple myeloma. Eur Radiol 2010; 20:2907-16. [PMID: 20574630 DOI: 10.1007/s00330-010-1865-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 05/11/2010] [Accepted: 05/19/2010] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To evaluate a whole body (WB) continuous-table-movement (CTM) MR protocol for the assessment of multiple myeloma (MM) in comparison to a step-by-step WB protocol. METHODS Eighteen patients with MM were examined at 1.5T using a WB CTM protocol (axial T2-w fs BLADE, T1-w GRE sequence) and a step-by-step WB protocol including coronal/sagittal T1-w SE and STIR sequences as reference. Protocol time was assessed. Image quality, artefacts, liver/spleen assessability, and the ability to depict bone marrow lesions less than or greater than 1 cm as well as diffuse infiltration and soft tissue lesions were rated. Potential changes in the Durie and Salmon Plus stage and the detectability of complications were assessed. RESULTS Mean protocol time was 6:38 min (CTM) compared to 24:32 min (standard). Image quality was comparable. Artefacts were more prominent using the CTM protocol (P = 0.0039). Organ assessability was better using the CTM protocol (P < 0.001). Depiction of bone marrow and soft tissue lesions was identical without a staging shift. Vertebral fractures were not detected using the CTM protocol. CONCLUSIONS The new protocol allows a higher patient throughput and facilitates the depiction of extramedullary lesions. However, as long as vertebral fractures are not detectable, the protocol cannot be safely used for clinical routine without the acquisition of an additional sagittal sequence.
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Affiliation(s)
- S Weckbach
- Department of Clinical Radiology, University Hospital Munich-Grosshadern Campus, Marchioninistr. 15, 81377, Munich, Germany.
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Huff S, Honal M, Baumann T, Hennig J, Markl M, Ludwig U. Continuously moving table time-of-flight angiography of the peripheral veins. Magn Reson Med 2010; 63:1219-29. [DOI: 10.1002/mrm.22296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sandra Huff
- Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany.
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Honal M, Leupold J, Huff S, Baumann T, Ludwig U. Compensation of breathing motion artifacts for MRI with continuously moving table. Magn Reson Med 2010; 63:701-12. [DOI: 10.1002/mrm.22162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Zenge MO, Ladd ME, Quick HH. Novel reconstruction method for three-dimensional axial continuously moving table whole-body magnetic resonance imaging featuring autocalibrated parallel imaging GRAPPA. Magn Reson Med 2009; 61:867-73. [DOI: 10.1002/mrm.21859] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Baumann T, Ludwig U, Pache G, Fautz HP, Kotter E, Langer M, Schaefer O. Continuously moving table MRI with sliding multislice for rectal cancer staging: image quality and lesion detection. Eur J Radiol 2009; 73:579-87. [PMID: 19179029 DOI: 10.1016/j.ejrad.2008.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/04/2008] [Accepted: 12/10/2008] [Indexed: 12/27/2022]
Abstract
PURPOSE To determine image quality and lesion detection of sliding multislice (SMS), a recently developed moving table MRI technique, in patients with rectal cancer. MATERIALS AND METHODS Twenty-seven paired SMS (Avanto, Siemens Medical Solutions) and MDCT (Sensation 64, Siemens Medical Solutions) examinations of abdomen and pelvis were performed in patients with rectal cancer and compared for detection of liver, lymph node and bone metastases by two independent observers. A contrast-enhanced, fat saturated 2D gradient echo sequence (TE, 2.0 ms; TR, 102 ms; slice, 5 mm) was acquired with SMS and a standard contrast-enhanced protocol (100 ml @ 2.5 ml/s; slice, 5 mm) was used for abdominal MDCT. Standard of reference consisted of a consensus evaluation of SMS, MDCT, and all available follow-up examinations after a period of 6 months. Artifact burden and image quality of SMS was assessed in comparison to stationary gradient echo sequences obtained in an age-matched group of 27 patients. RESULTS Whereas SMS achieved a mean quality score of 3.65 (scale, 0-4) for the liver, representing very good diagnostic properties, strong breathing artifacts in the intestinal region were observed in 19 cases by both observers. The retroperitoneum still achieved a mean quality score of 3.52, although breathing artifacts were noted in 12 and 15 cases (observers 1 and 2, respectively). The sensitivities of SMS to detect hepatic metastases were 91.2% and 94.1% for both observers, respectively, compared to 98.5%/98.5% for MDCT. The sensitivities for lymph node metastases were 87.5%/81.3% for SMS compared to 78.1%/81.3% for MDCT. The sensitivities for bone metastases were 91.7%/100% for SMS compared to 8.3%/16.7% for MDCT. CONCLUSION With slightly reduced image quality in the intestinal region, SMS exhibits equal detection of lymph node and liver metastases compared to MDCT. SMS MRI proved to be superior to MDCT in detection of bone metastases.
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Affiliation(s)
- Tobias Baumann
- Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany.
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Detection of pulmonary nodules with move-during-scan magnetic resonance imaging using a free-breathing turbo inversion recovery magnitude sequence. Invest Radiol 2008; 43:359-67. [PMID: 18496040 DOI: 10.1097/rli.0b013e31816901fa] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Detection of pulmonary metastases is still a challenging task for magnetic resonance imaging (MRI). It was the aim of this study to evaluate the potential of a free-breathing move-during-scan turbo inversion recovery magnitude sequence for the detection of pulmonary nodules. MATERIALS AND METHODS The sensitivities and positive-predictive values of 2 radiologists to detect pulmonary nodules in 41 move-during-scan MRI examinations of 38 patients with different malignancies were calculated and subgroup analyses according to lesion size and localization were performed. Multidetector computed tomography served as the standard of reference. Additionally, 6 radiologists rated the confidence for the presence of nodular lesions in 212 regions-of-interest, which were randomly selected to represent lesions of various sizes as well as negative findings. Receiver-operator-characteristic was performed. RESULTS Three hundred twenty-one nodules were found in 30 patients by multidetector computed tomography. Sensitivity and specificity of MRI to detect pulmonary nodules larger than 3 mm on a per-patient basis were 81.8% and 94.7%, respectively. On a per-lesion basis, MRI revealed a sensitivity of 79.0% to 80.7% for lesions larger than 3 mm, if high conspicuity ratings were counted as positive, and 84.6%, if medium and high conspicuity ratings were counted as positive. Sensitivity increased uniformly with lesion size, and all lesions larger than 12 mm were detected. Receiver-operator-characteristic analysis revealed a mean accuracy of 0.90 and sensitivities over 90% for lesions larger than 3 mm with a specificity of 96.1%. For lesions larger than 6 mm the accuracy was 0.99. CONCLUSION Detection of pulmonary nodules with a move-during-scan turbo inversion recovery magnitude sequence is feasible. Excellent detection of lesions larger than 6 mm is achievable with free-breathing moving-table MRI.
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Börnert P, Aldefeld B. Principles of whole-body continuously-moving-table MRI. J Magn Reson Imaging 2008; 28:1-12. [DOI: 10.1002/jmri.21339] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Sommer G, Schaefer AO, Baumann T, Ludwig UA, Fautz HP. Sliding multislice MRI for abdominal staging of patients with pelvic malignancies: A pilot study. J Magn Reson Imaging 2008; 27:666-72. [DOI: 10.1002/jmri.21279] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Schäfer AO, Baumann T, Pache G, Wiech T, Langer M. [Preoperative staging of rectal cancer]. Radiologe 2007; 47:635-51; quiz 652. [PMID: 17581734 DOI: 10.1007/s00117-007-1516-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Accurate preoperative staging of rectal cancer is crucial for therapeutic decision making, as local tumor extent, nodal status, and patterns of metastatic spread are directly associated with different treatment strategies. Recently, treatment approaches have been widely standardized according to large studies and consensus guidelines. Introduced by Heald, total mesorectal excision (TME) is widely accepted as the surgical procedure of choice to remove the rectum together with its enveloping tissues and the mesorectal fascia. Neoadjuvant radiochemotherapy also plays a key role in the treatment of locally advanced stages, while the use of new drugs will lead to a further improvement in oncological outcome. Visualization of the circumferential resection margin is the hallmark of any preoperative imaging and a prerequisite for high-quality TME surgery. The aim of this article is to present an overview on current cross-sectional imaging with emphasis on magnetic resonance imaging. Future perspectives in rectal cancer imaging are addressed.
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Affiliation(s)
- A-O Schäfer
- Abteilung Röntgendiagnostik, Radiologische Universitätsklinik Freiburg, Freiburg im Breisgau.
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Schaefer O, Langer M. Detection of recurrent rectal cancer with CT, MRI and PET/CT. Eur Radiol 2007; 17:2044-54. [PMID: 17404742 DOI: 10.1007/s00330-007-0613-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 02/07/2007] [Accepted: 02/09/2007] [Indexed: 02/08/2023]
Abstract
Computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) all have the potential to directly visualize local and distant relapse of colorectal cancer (CRC). Nevertheless, the role of diagnostic imaging for routine follow-up of CRC patients remains controversial. Although MRI and PET have advantages over CT in the detection of local recurrence, until now only a few surveillance programs recommend the use of annual CT for routine follow-up. The objective of this review is to elucidate the current status of diagnostic imaging for the detection of recurrent rectal cancer based on the recent literature and our own experience. Furthermore, an insight into contemporary surveillance programs and an outlook concerning a novel technical approach to moving-table MRI at 1.5 Tesla for staging purposes are given.
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Affiliation(s)
- O Schaefer
- Department of Diagnostic Radiology, University Hospital Feiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
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Fautz HP, Honal M, Saueressig U, Schäfer O, Kannengiesser SAR. Artifact reduction in moving-table acquisitions using parallel imaging and multiple averages. Magn Reson Med 2007; 57:226-32. [PMID: 17191244 DOI: 10.1002/mrm.21117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Two-dimensional (2D) axial continuously-moving-table imaging has to deal with artifacts due to gradient nonlinearity and breathing motion, and has to provide the highest scan efficiency. Parallel imaging techniques (e.g., generalized autocalibrating partially parallel acquisition GRAPPA)) are used to reduce such artifacts and avoid ghosting artifacts. The latter occur in T(2)-weighted multi-spin-echo (SE) acquisitions that omit an additional excitation prior to imaging scans for presaturation purposes. Multiple images are reconstructed from subdivisions of a fully sampled k-space data set, each of which is acquired in a single SE train. These images are then averaged. GRAPPA coil weights are estimated without additional measurements. Compared to conventional image reconstruction, inconsistencies between different subsets of k-space induce less artifacts when each k-space part is reconstructed separately and the multiple images are averaged afterwards. These inconsistencies may lead to inaccurate GRAPPA coil weights using the proposed intrinsic GRAPPA calibration. It is shown that aliasing artifacts in single images are canceled out after averaging. Phantom and in vivo studies demonstrate the benefit of the proposed reconstruction scheme for free-breathing axial continuously-moving-table imaging using fast multi-SE sequences.
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Affiliation(s)
- H P Fautz
- Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany.
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