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Semiautomatic assessment of respiratory dynamics using cine MRI in chronic obstructive pulmonary disease. Eur J Radiol Open 2022; 9:100442. [PMID: 36193450 PMCID: PMC9525813 DOI: 10.1016/j.ejro.2022.100442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 09/19/2022] [Accepted: 09/26/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose The quantitative assessment of impaired lung motions and their association with the clinical characteristics of COPD patients is challenging. The aim of this study was to measure respiratory kinetics, including asynchronous movements, and to analyze the relationship between lung area and other clinical parameters. Materials and methods This study enrolled 10 normal control participants and 21 COPD patients who underwent dynamic MRI and pulmonary function testing (PFT). The imaging program was implemented using MATLAB®. Each lung area was detected semi-automatically on a coronal image (imaging level at the aortic valve) from the inspiratory phase to the expiratory phase. The Dice index of the manual measurements was calculated, with the relationship between lung area ratio and other clinical parameters, including PFTs then evaluated. The asynchronous movements of the diaphragm were also evaluated using a sagittal image. Results The Dice index for the lung region using the manual and semi-automatic extraction methods was high (Dice index = 0.97 ± 0.03). A significant correlation was observed between the time corrected lung area ratio and percentage of forced expiratory volume in 1 s (FEV1%pred) and residual volume percentage (RV%pred) (r = −0.54, p = 0.01, r = 0.50, p = 0.03, respectively). The correlation coefficient between each point of the diaphragm in the group with visible see-saw like movements was significantly lower than that in the group without see-saw like movements (value = −0.36 vs 0.95, p = 0.001). Conclusion Semi-automated extraction of lung area from Cine MRI might be useful for detecting impaired respiratory kinetics in patients with COPD.
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Key Words
- Asynchronous movement
- BMI, body mass index
- CAT, chronic obstructive pulmonary disease assessment test
- COPD, chronic obstructive pulmonary disease
- Chronic obstructive pulmonary disease (COPD)
- DLCO, carbon monoxide diffusing capacity of the lung
- Diaphragm
- FEV1, forced expiratory volume in 1 s
- FEV1/FVC, forced expiratory volume in 1 s per forced vital capacity
- FLASH, fast low angle shot
- FOV, field of view
- FRC, functional residual capacity
- FVC, forced vital capacity
- GOLD, Global Initiative for Chronic Pulmonary Obstructive Lung Disease
- HASTE, Half Fourier Acquisition Single-shot Turbo spin Echo
- ICC, intraclass correlation coefficient
- ICS, inhaled corticosteroid
- LAA, low attenuation area
- LABA, long-acting β-2 agonist
- LAMA, long-acting muscarinic antagonists
- LAV, low attenuation volume
- LV, lung volume
- Lung area
- MDCT, multi-detector row computed tomography
- MRI, magnetic resonance imaging
- Magnetic resonance imaging (MRI)
- PFT, pulmonary function testing
- Pulmonary function
- RV, residual volume
- RV/TLC, residual volume per total lung capacity
- SSFP, steady-state free precession
- TLA, total lung area
- TLC, total lung capacity
- UTE, ultrashort echo time
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Murase K, Kashiwagi N, Tomiyama N. Quantitative evaluation of simultaneous spatial and temporal regularization in dynamic contrast-enhanced MRI of the liver using Gd-EOB-DTPA. Magn Reson Imaging 2022; 88:25-37. [PMID: 35007694 DOI: 10.1016/j.mri.2022.01.006] [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: 10/04/2021] [Revised: 01/02/2022] [Accepted: 01/04/2022] [Indexed: 02/07/2023]
Abstract
The purpose of this study was to quantitatively evaluate the usefulness of simultaneous spatial and temporal regularization using total variation (TV), total generalized variation (TGV), a combination of low-rank decomposition (LRD) and TV (LRD+TV), a combination of LRD and TGV (LRD+TGV), and nuclear norm (NN) when applied to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rats with concanavalin A (ConA)-induced acute hepatic injury. The rats were divided into three groups: normal control (NC) (n = 10), ConA10 (n = 8), and ConA20 (n = 7). Rats in the ConA10 and ConA20 groups were intravenously injected with 10 and 20 mg/kg of ConA, respectively; those in the NC group were intravenously injected with the same volume of saline. DCE-MRI studies were performed using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA; 0.025 mmol Gd/kg) as a contrast agent (CA), 24 h after the ConA or saline injection. After the DCE-MRI study, we generated zero-filled and undersampled k-space data from the original images using a pseudoradial sampling scheme with 4 to 64 spokes. We subsequently reconstructed images from these data using the above regularizers and calculated the signal-to-error ratio (SERimg) and structural similarity index (SSIM) using the original and reconstructed images. We also calculated the area under the curve (AUC), rate of CA washout (λw), maximum relative enhancement (REmax), and time to REmax (Tmax) from time-intensity curves using an empirical mathematical model (EMM) and the signal-to-error ratio for curve fitting (SERfit) from the original and fit curves. We also compared the parameters obtained using the pseudoradial and Cartesian sampling schemes in the NC group. When using LRD+TV and LRD+TGV, both SERimg and SSIM were greater than those for the other regularizers at all spoke numbers studied; the SERfit for TGV was the greatest. When using TGV and LRD+TGV, in the majority of cases the AUCs did not significantly differ from those obtained from the original images, whereas those for LRD+TV and NN were significantly less at several spoke numbers. The λw for NN was significantly greater at numerous spoke numbers in the NC group; the REmax values for LRD+TV and NN were significantly less at several spoke numbers in all groups. The Tmax values for TV, TGV, and LRD+TGV were significantly greater at numerous spoke numbers in the NC group. Although there were significant differences in SERimg and SSIM between the pseudoradial and Cartesian sampling schemes, the kinetic parameters obtained by the EMM did not significantly differ between the two sampling schemes, with certain exceptions. In conclusion, our results suggest that simultaneous spatial and temporal regularization using TGV or LRD+TGV is useful for accelerating DCE-MRI without significant reduction in the accuracy of the kinetic parameter estimation, even at extremely low sampling factors.
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Affiliation(s)
- Kenya Murase
- Department of Future Diagnostic Radiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Nobuo Kashiwagi
- Department of Future Diagnostic Radiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Noriyuki Tomiyama
- Department of Diagnostic and Interventional Radiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
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Sato H, Kawata N, Shimada A, Suzuki T. [Semi-automated Segmentation of Lungs Using the k-means Method in Cine MRI]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2021; 77:1298-1308. [PMID: 34803110 DOI: 10.6009/jjrt.2021_jsrt_77.11.1298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dynamic magnetic resonance imaging (MRI) provides essential information on the respiratory kinetics in chronic obstructive pulmonary disease (COPD), such as impaired diaphragm and chest wall motions. The purpose of this study was to develop the semi-automated segmentation program of lungs using cine MRI. We enrolled five control participants and five patients with COPD who underwent cine MRI. The coronal balanced FFE images from each subject were used. The procedures were as follows: First, the maximum inspiratory image was selected from the time-sequential series, and the lung area was manually segmented, which was used for a mask image. Second, both mask image and cine image were accumulated to create a weighted cine image. Lung areas were segmented using the k-means method. Finally, lungs were detected as contiguous image regions with similar signal values using the flood-fill technique. We evaluated the correlation coefficients between the lung area segmented by the semi-automated method and those segmented by a pulmonologist. The correlation coefficients between the semi-automated method and the manual segmentations were excellent (r=0.99, p<0.001). The Dice index was also perfect (0.97). The best number of clusters in the k-means method was 8. These results suggested that the new segmentation method can appropriately extract lungs and help analyze respiratory dynamics in patients with COPD.
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Affiliation(s)
- Hirotaka Sato
- Department of Radiological Technology, Soka Municipal Hospital.,Department of Respirology, Chiba University Graduate School of Medicine
| | - Naoko Kawata
- Department of Respirology, Chiba University Graduate School of Medicine
| | - Ayako Shimada
- Department of Respirology, Shin-Yurigaoka General Hospital
| | - Takuji Suzuki
- Department of Respirology, Chiba University Graduate School of Medicine
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Compressed Sensing and Parallel Imaging for Double Hepatic Arterial Phase Acquisition in Gadoxetate-Enhanced Dynamic Liver Magnetic Resonance Imaging. Invest Radiol 2019; 54:374-382. [DOI: 10.1097/rli.0000000000000548] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Sjöholm T, Ekström S, Strand R, Ahlström H, Lind L, Malmberg F, Kullberg J. A whole-body FDG PET/MR atlas for multiparametric voxel-based analysis. Sci Rep 2019; 9:6158. [PMID: 30992502 PMCID: PMC6467986 DOI: 10.1038/s41598-019-42613-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 04/04/2019] [Indexed: 01/12/2023] Open
Abstract
Quantitative multiparametric imaging is a potential key application for Positron Emission Tomography/Magnetic Resonance (PET/MR) hybrid imaging. To enable objective and automatic voxel-based multiparametric analysis in whole-body applications, the purpose of this study was to develop a multimodality whole-body atlas of functional 18F-fluorodeoxyglucose (FDG) PET and anatomical fat-water MR data of adults. Image registration was used to transform PET/MR images of healthy control subjects into male and female reference spaces, producing a fat-water MR, local tissue volume and FDG PET whole-body normal atlas consisting of 12 male (66.6 ± 6.3 years) and 15 female (69.5 ± 3.6 years) subjects. Manual segmentations of tissues and organs in the male and female reference spaces confirmed that the atlas contained adequate physiological and anatomical values. The atlas was applied in two anomaly detection tasks as proof of concept. The first task automatically detected anomalies in two subjects with suspected malignant disease using FDG data. The second task successfully detected abnormal liver fat infiltration in one subject using fat fraction data.
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Affiliation(s)
- Therese Sjöholm
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
| | - Simon Ekström
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Robin Strand
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Håkan Ahlström
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Antaros Medical AB, Mölndal, Sweden
| | - Lars Lind
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Filip Malmberg
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Joel Kullberg
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Antaros Medical AB, Mölndal, Sweden
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Blind Compressed Sensing Enables 3-Dimensional Dynamic Free Breathing Magnetic Resonance Imaging of Lung Volumes and Diaphragm Motion. Invest Radiol 2017; 51:387-99. [PMID: 26863578 DOI: 10.1097/rli.0000000000000253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The objective of this study was to increase the spatial and temporal resolution of dynamic 3-dimensional (3D) magnetic resonance imaging (MRI) of lung volumes and diaphragm motion. To achieve this goal, we evaluate the utility of the proposed blind compressed sensing (BCS) algorithm to recover data from highly undersampled measurements. MATERIALS AND METHODS We evaluated the performance of the BCS scheme to recover dynamic data sets from retrospectively and prospectively undersampled measurements. We also compared its performance against that of view-sharing, the nuclear norm minimization scheme, and the l1 Fourier sparsity regularization scheme. Quantitative experiments were performed on a healthy subject using a fully sampled 2D data set with uniform radial sampling, which was retrospectively undersampled with 16 radial spokes per frame to correspond to an undersampling factor of 8. The images obtained from the 4 reconstruction schemes were compared with the fully sampled data using mean square error and normalized high-frequency error metrics. The schemes were also compared using prospective 3D data acquired on a Siemens 3 T TIM TRIO MRI scanner on 8 healthy subjects during free breathing. Two expert cardiothoracic radiologists (R1 and R2) qualitatively evaluated the reconstructed 3D data sets using a 5-point scale (0-4) on the basis of spatial resolution, temporal resolution, and presence of aliasing artifacts. RESULTS The BCS scheme gives better reconstructions (mean square error = 0.0232 and normalized high frequency = 0.133) than the other schemes in the 2D retrospective undersampling experiments, producing minimally distorted reconstructions up to an acceleration factor of 8 (16 radial spokes per frame). The prospective 3D experiments show that the BCS scheme provides visually improved reconstructions than the other schemes do. The BCS scheme provides improved qualitative scores over nuclear norm and l1 Fourier sparsity regularization schemes in the temporal blurring and spatial blurring categories. The qualitative scores for aliasing artifacts in the images reconstructed by nuclear norm scheme and BCS scheme are comparable.The comparisons of the tidal volume changes also show that the BCS scheme has less temporal blurring as compared with the nuclear norm minimization scheme and the l1 Fourier sparsity regularization scheme. The minute ventilation estimated by BCS for tidal breathing in supine position (4 L/min) and the measured supine inspiratory capacity (1.5 L) is in good correlation with the literature. The improved performance of BCS can be explained by its ability to efficiently adapt to the data, thus providing a richer representation of the signal. CONCLUSION The feasibility of the BCS scheme was demonstrated for dynamic 3D free breathing MRI of lung volumes and diaphragm motion. A temporal resolution of ∼500 milliseconds, spatial resolution of 2.7 × 2.7 × 10 mm, with whole lung coverage (16 slices) was achieved using the BCS scheme.
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A decade of lung expansion: A review of ventilation-weighted 1 H lung MRI. Z Med Phys 2017; 27:172-179. [DOI: 10.1016/j.zemedi.2016.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/10/2016] [Accepted: 07/26/2016] [Indexed: 11/30/2022]
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Respiratory dynamics in phonation and breathing—A real-time MRI study. Respir Physiol Neurobiol 2017; 236:69-77. [DOI: 10.1016/j.resp.2016.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 11/08/2016] [Accepted: 11/13/2016] [Indexed: 11/17/2022]
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Mogalle K, Perez-Rovira A, Ciet P, Wens SCA, van Doorn PA, Tiddens HAWM, van der Ploeg AT, de Bruijne M. Quantification of Diaphragm Mechanics in Pompe Disease Using Dynamic 3D MRI. PLoS One 2016; 11:e0158912. [PMID: 27391236 PMCID: PMC4938606 DOI: 10.1371/journal.pone.0158912] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/23/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Diaphragm weakness is the main reason for respiratory dysfunction in patients with Pompe disease, a progressive metabolic myopathy affecting respiratory and limb-girdle muscles. Since respiratory failure is the major cause of death among adult patients, early identification of respiratory muscle involvement is necessary to initiate treatment in time and possibly prevent irreversible damage. In this paper we investigate the suitability of dynamic MR imaging in combination with state-of-the-art image analysis methods to assess respiratory muscle weakness. METHODS The proposed methodology relies on image registration and lung surface extraction to quantify lung kinematics during breathing. This allows for the extraction of geometry and motion features of the lung that characterize the independent contribution of the diaphragm and the thoracic muscles to the respiratory cycle. RESULTS Results in 16 3D+t MRI scans (10 Pompe patients and 6 controls) of a slow expiratory maneuver show that kinematic analysis from dynamic 3D images reveals important additional information about diaphragm mechanics and respiratory muscle involvement when compared to conventional pulmonary function tests. Pompe patients with severely reduced pulmonary function showed severe diaphragm weakness presented by minimal motion of the diaphragm. In patients with moderately reduced pulmonary function, cranial displacement of posterior diaphragm parts was reduced and the diaphragm dome was oriented more horizontally at full inspiration compared to healthy controls. CONCLUSION Dynamic 3D MRI provides data for analyzing the contribution of both diaphragm and thoracic muscles independently. The proposed image analysis method has the potential to detect less severe diaphragm weakness and could thus be used to determine the optimal start of treatment in adult patients with Pompe disease in prospect of increased treatment response.
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Affiliation(s)
- Katja Mogalle
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics & Radiology, Erasmus MC, Rotterdam, the Netherlands
- * E-mail: (KM); (MdB)
| | - Adria Perez-Rovira
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics & Radiology, Erasmus MC, Rotterdam, the Netherlands
- Department of Pediatric Pulmonology, Erasmus MC-Sophia Children’s Hospital, Rotterdam, the Netherlands
| | - Pierluigi Ciet
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands
- Department of Pediatrics, Respiratory Medicine and Allergology, Erasmus MC-Sophia, Rotterdam, the Netherlands
| | - Stephan C. A. Wens
- Department of Neurology, Erasmus MC, Rotterdam, the Netherlands
- Centre for Lysosomal and Metabolic Diseases, Erasmus MC-Sophia, Rotterdam, the Netherlands
| | - Pieter A. van Doorn
- Department of Neurology, Erasmus MC, Rotterdam, the Netherlands
- Centre for Lysosomal and Metabolic Diseases, Erasmus MC-Sophia, Rotterdam, the Netherlands
| | - Harm A. W. M. Tiddens
- Department of Radiology, Erasmus MC, Rotterdam, the Netherlands
- Department of Pediatrics, Respiratory Medicine and Allergology, Erasmus MC-Sophia, Rotterdam, the Netherlands
| | - Ans T. van der Ploeg
- Centre for Lysosomal and Metabolic Diseases, Erasmus MC-Sophia, Rotterdam, the Netherlands
- Department of Pediatrics, Division of Metabolic Diseases and Genetics, Erasmus MC-Sophia, Rotterdam, the Netherlands
| | - Marleen de Bruijne
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics & Radiology, Erasmus MC, Rotterdam, the Netherlands
- Department of Computer Science, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (KM); (MdB)
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Yang YX, Teo SK, Van Reeth E, Tan CH, Tham IWK, Poh CL. A hybrid approach for fusing 4D-MRI temporal information with 3D-CT for the study of lung and lung tumor motion. Med Phys 2016; 42:4484-96. [PMID: 26233178 DOI: 10.1118/1.4923167] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Accurate visualization of lung motion is important in many clinical applications, such as radiotherapy of lung cancer. Advancement in imaging modalities [e.g., computed tomography (CT) and MRI] has allowed dynamic imaging of lung and lung tumor motion. However, each imaging modality has its advantages and disadvantages. The study presented in this paper aims at generating synthetic 4D-CT dataset for lung cancer patients by combining both continuous three-dimensional (3D) motion captured by 4D-MRI and the high spatial resolution captured by CT using the authors' proposed approach. METHODS A novel hybrid approach based on deformable image registration (DIR) and finite element method simulation was developed to fuse a static 3D-CT volume (acquired under breath-hold) and the 3D motion information extracted from 4D-MRI dataset, creating a synthetic 4D-CT dataset. RESULTS The study focuses on imaging of lung and lung tumor. Comparing the synthetic 4D-CT dataset with the acquired 4D-CT dataset of six lung cancer patients based on 420 landmarks, accurate results (average error <2 mm) were achieved using the authors' proposed approach. Their hybrid approach achieved a 40% error reduction (based on landmarks assessment) over using only DIR techniques. CONCLUSIONS The synthetic 4D-CT dataset generated has high spatial resolution, has excellent lung details, and is able to show movement of lung and lung tumor over multiple breathing cycles.
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Affiliation(s)
- Y X Yang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459
| | - S-K Teo
- Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore 138632
| | - E Van Reeth
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459
| | - C H Tan
- Department of Diagnostic Radiology, Tan Tock Seng Hospital, Singapore 308433
| | - I W K Tham
- Department of Radiation Oncology, National University Cancer Institute, Singapore 119082
| | - C L Poh
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459
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Park J, Shin T, Yoon SH, Goo JM, Park JY. A radial sampling strategy for uniform k-space coverage with retrospective respiratory gating in 3D ultrashort-echo-time lung imaging. NMR IN BIOMEDICINE 2016; 29:576-87. [PMID: 26891126 PMCID: PMC4833643 DOI: 10.1002/nbm.3494] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 12/22/2015] [Accepted: 01/01/2016] [Indexed: 05/07/2023]
Abstract
The purpose of this work was to develop a 3D radial-sampling strategy which maintains uniform k-space sample density after retrospective respiratory gating, and demonstrate its feasibility in free-breathing ultrashort-echo-time lung MRI. A multi-shot, interleaved 3D radial sampling function was designed by segmenting a single-shot trajectory of projection views such that each interleaf samples k-space in an incoherent fashion. An optimal segmentation factor for the interleaved acquisition was derived based on an approximate model of respiratory patterns such that radial interleaves are evenly accepted during the retrospective gating. The optimality of the proposed sampling scheme was tested by numerical simulations and phantom experiments using human respiratory waveforms. Retrospectively, respiratory-gated, free-breathing lung MRI with the proposed sampling strategy was performed in healthy subjects. The simulation yielded the most uniform k-space sample density with the optimal segmentation factor, as evidenced by the smallest standard deviation of the number of neighboring samples as well as minimal side-lobe energy in the point spread function. The optimality of the proposed scheme was also confirmed by minimal image artifacts in phantom images. Human lung images showed that the proposed sampling scheme significantly reduced streak and ring artifacts compared with the conventional retrospective respiratory gating while suppressing motion-related blurring compared with full sampling without respiratory gating. In conclusion, the proposed 3D radial-sampling scheme can effectively suppress the image artifacts due to non-uniform k-space sample density in retrospectively respiratory-gated lung MRI by uniformly distributing gated radial views across the k-space.
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Affiliation(s)
- Jinil Park
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, South Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Taehoon Shin
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland, Baltimore, MD, USA
| | - Soon Ho Yoon
- Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea
| | - Jin Mo Goo
- Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea
- Cancer Research Institute, Seoul National University, Seoul, South Korea
| | - Jang-Yeon Park
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, South Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
- Correspondence to: J.-Y. Park, Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, South Korea.
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Ivanovska T, Hegenscheid K, Laqua R, Gläser S, Ewert R, Völzke H. Lung Segmentation of MR Images: A Review. VISUALIZATION IN MEDICINE AND LIFE SCIENCES III 2016. [DOI: 10.1007/978-3-319-24523-2_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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13
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Koyama H, Ohno Y, Fujisawa Y, Seki S, Negi N, Murakami T, Yoshikawa T, Sugihara N, Nishimura Y, Sugimura K. 3D lung motion assessments on inspiratory/expiratory thin-section CT: Capability for pulmonary functional loss of smoking-related COPD in comparison with lung destruction and air trapping. Eur J Radiol 2015; 85:352-9. [PMID: 26781140 DOI: 10.1016/j.ejrad.2015.11.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/14/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE To evaluate the utility of three-dimensional (3D) lung motion on inspiratory and expiratory CT for pulmonary functional loss in smoking-related COPD in comparison with lung destruction and air trapping assessments. METHOD AND MATERIALS Forty-four consecutive smokers and COPD patients prospectively underwent inspiratory and expiratory CT. A 3D motion vector map was generated from these CTs, and regional motion magnitudes were measured at the horizontal axis (X-axis), the ventrodorsal axis (Y-axis), and the craniocaudal axis (Z-axis). All mean magnitudes within the entire lung (MMLX, MMLY, and MMLZ) were normalized by expiratory CT lung volume. Moreover, CT-based functional lung volume (FLV) on inspiratory CT and air trapping lung volume (ATLV) on expiratory CT were assessed quantitatively. To evaluate the capability for pulmonary function loss assessment, all MMLs were correlated with pulmonary function tests. Then, discrimination analysis was performed to determine the concordance capability for clinical stage, and correct classification capabilities were compared by means of McNemar's test. RESULTS Multiple regression analysis showed MMLY (β=0.657, p<0.001) and FLV (β=0.375, p=0.019) were correlated with percentage of predicted forced expiratory volume in 1 second. Correct classification capabilities using patient characteristics and MMLs (68.2 (30/44)%) were significantly higher than those obtained by patient characteristics, FLV, and ATLV (54.5 (24/44)%), p=0.031). CONCLUSION 3D lung motion parameter assessment is useful for smoking-related COPD assessment as well as lung parenchymal destruction and/or air trapping evaluations.
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Affiliation(s)
- Hisanobu Koyama
- Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Yoshiharu Ohno
- Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan; Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yasuko Fujisawa
- Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan
| | - Shinichiro Seki
- Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Noriyuki Negi
- Center for Radiology and Radiation Oncology, Kobe University Hospital, Japan
| | - Tohru Murakami
- Center for Radiology and Radiation Oncology, Kobe University Hospital, Japan
| | - Takeshi Yoshikawa
- Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan; Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoki Sugihara
- Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan
| | - Yoshihiro Nishimura
- Division of Respiratory Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazuro Sugimura
- Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
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Berman BP, Pandey A, Li Z, Jeffries L, Trouard TP, Oliva I, Cortopassi F, Martin DR, Altbach MI, Bilgin A. Volumetric MRI of the lungs during forced expiration. Magn Reson Med 2015; 75:2295-302. [DOI: 10.1002/mrm.25798] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/06/2015] [Accepted: 05/11/2015] [Indexed: 01/11/2023]
Affiliation(s)
- Benjamin P. Berman
- Program in Applied Mathematics; University of Arizona; Tucson Arizona USA
| | - Abhishek Pandey
- Department of Electrical and Computer Engineering; University of Arizona; Tucson Arizona USA
| | - Zhitao Li
- Department of Electrical and Computer Engineering; University of Arizona; Tucson Arizona USA
| | - Lindsie Jeffries
- Department of Biomedical Engineering; University of Arizona; Tucson Arizona USA
| | - Theodore P. Trouard
- Department of Biomedical Engineering; University of Arizona; Tucson Arizona USA
- Department of Medical Imaging; University of Arizona; Tucson Arizona USA
| | - Isabel Oliva
- Department of Medical Imaging; University of Arizona; Tucson Arizona USA
| | - Felipe Cortopassi
- Department of Medical Imaging; University of Arizona; Tucson Arizona USA
| | - Diego R. Martin
- Department of Medical Imaging; University of Arizona; Tucson Arizona USA
| | - Maria I. Altbach
- Department of Medical Imaging; University of Arizona; Tucson Arizona USA
| | - Ali Bilgin
- Department of Electrical and Computer Engineering; University of Arizona; Tucson Arizona USA
- Department of Biomedical Engineering; University of Arizona; Tucson Arizona USA
- Department of Medical Imaging; University of Arizona; Tucson Arizona USA
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15
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Ciet P, Tiddens HAWM, Wielopolski PA, Wild JM, Lee EY, Morana G, Lequin MH. Magnetic resonance imaging in children: common problems and possible solutions for lung and airways imaging. Pediatr Radiol 2015; 45:1901-15. [PMID: 26342643 PMCID: PMC4666905 DOI: 10.1007/s00247-015-3420-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 04/20/2015] [Accepted: 06/17/2015] [Indexed: 11/11/2022]
Abstract
Pediatric chest MRI is challenging. High-resolution scans of the lungs and airways are compromised by long imaging times, low lung proton density and motion. Low signal is a problem of normal lung. Lung abnormalities commonly cause increased signal intenstities. Among the most important factors for a successful MRI is patient cooperation, so the long acquisition times make patient preparation crucial. Children usually have problems with long breath-holds and with the concept of quiet breathing. Young children are even more challenging because of higher cardiac and respiratory rates giving motion blurring. For these reasons, CT has often been preferred over MRI for chest pediatric imaging. Despite its drawbacks, MRI also has advantages over CT, which justifies its further development and clinical use. The most important advantage is the absence of ionizing radiation, which allows frequent scanning for short- and long-term follow-up studies of chronic diseases. Moreover, MRI allows assessment of functional aspects of the chest, such as lung perfusion and ventilation, or airways and diaphragm mechanics. In this review, we describe the most common MRI acquisition techniques on the verge of clinical translation, their problems and the possible solutions to make chest MRI feasible in children.
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Affiliation(s)
- Pierluigi Ciet
- Department of Radiology, Sophia Children’s Hospital, Erasmus Medical Center, Rotterdam, The Netherlands ,Department of Pediatric Pulmonology and Allergology, Sophia Children’s Hospital, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Harm A. W. M. Tiddens
- Department of Radiology, Sophia Children’s Hospital, Erasmus Medical Center, Rotterdam, The Netherlands ,Department of Pediatric Pulmonology and Allergology, Sophia Children’s Hospital, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Piotr A. Wielopolski
- Department of Radiology, Sophia Children’s Hospital, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jim M. Wild
- Academic Radiology, University of Sheffield, Sheffield, UK
| | - Edward Y. Lee
- Departments of Radiology and Medicine, Pulmonary Divisions, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - Giovanni Morana
- Department of Radiology, Ca’ Foncello Regional Hospital, Treviso, Italy
| | - Maarten H. Lequin
- Department of Radiology, Wilhelmina Children’s Hospital, University Medical Center, Wilhelmina Kinderziekenhuis (WKZ) Lundlaan 6, 3584 EA Utrecht, The Netherlands
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16
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Seddon P. Options for assessing and measuring chest wall motion. Paediatr Respir Rev 2015; 16:3-10. [PMID: 25468220 DOI: 10.1016/j.prrv.2014.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 10/22/2014] [Indexed: 11/16/2022]
Abstract
Assessing chest wall motion is a basic and vital component in managing the child with respiratory problems, whether these are due to pathology in the lungs, airways, chest wall or muscles. Since the 1960s, clinical assessment has been supplemented with an ever-growing range of technological options for measuring chest wall motion, each with unique advantages and disadvantages. Measurements of chest wall motion can be used to: (1) Assess respiratory airflow and volume change, as a non-invasive alternative to measurement at the airway opening, (2) Monitor breathing over long periods of time, to identify apnoea and other types of sleep-disordered breathing, (3)Identify and quantify patterns of abnormal chest wall movement, whether between ribcage and abdominal components (thoracoabdominal asynchrony) or between different regions of the ribcage (eg in scoliosis and pectus excavatum). Measuring chest wall motion allows us to do things which simply cannot be done by more mainstream respiratory function techniques measuring flow at the airway opening: it allows respiratory airflow to be measured when it would otherwise be impossible, and it tells us how the different parts of the chest wall (eg ribcage vs abdomen, right vs left) are moving in order to generate that airflow. The basis of the different techniques available to assess and measure chest wall motion will be reviewed and compared, and their relevance to paediatric respiratory practice assessed.
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Affiliation(s)
- Paul Seddon
- Consultant Respiratory Paediatrician, Royal Alexandra Children's Hospital, Eastern Road, Brighton BN2 5BE, United Kingdom.
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17
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Güldner M, Becker S, Wolf U, Düber C, Friesenecker A, Gast KK, Heil W, Hoffmann C, Karpuk S, Otten EW, Rivoire J, Salhi Z, Scholz A, Schreiber LM, Terekhov M. Application unit for the administration of contrast gases for pulmonary magnetic resonance imaging: optimization of ventilation distribution for (3) He-MRI. Magn Reson Med 2014; 74:884-93. [PMID: 25213218 DOI: 10.1002/mrm.25433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 08/05/2014] [Accepted: 08/06/2014] [Indexed: 11/05/2022]
Abstract
PURPOSE MRI of lung airspaces using gases with MR-active nuclei ((3) He, (129) Xe, and (19) F) is an important area of research in pulmonary imaging. The volume-controlled administration of gas mixtures is important for obtaining quantitative information from MR images. State-of-the-art gas administration using plastic bags (PBs) does not allow for a precise determination of both the volume and timing of a (3) He bolus. METHODS A novel application unit (AU) was built according to the requirements of the German medical devices law. Integrated spirometers enable the monitoring of the inhaled gas flow. The device is particularly suited for hyperpolarized (HP) gases (e.g., storage and administration with minimal HP losses). The setup was tested in a clinical trial (n = 10 healthy volunteers) according to the German medicinal products law using static and dynamic ventilation HP-(3) He MRI. RESULTS The required specifications for the AU were successfully realized. Compared to PB-administration, better reproducibility of gas intrapulmonary distribution was observed when using the AU for both static and dynamic ventilation imaging. CONCLUSION The new AU meets the special requirements for HP gases, which are storage and administration with minimal losses. Our data suggest that gas AU-administration is superior to manual modes for determining the key parameters of dynamic ventilation measurements.
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Affiliation(s)
- M Güldner
- Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
| | | | - U Wolf
- Department of Radiology, University Medical Center Mainz, Mainz, Germany
| | - C Düber
- Department of Radiology, University Medical Center Mainz, Mainz, Germany
| | | | - K K Gast
- Department of Radiology, University Medical Center Mainz, Mainz, Germany
| | - W Heil
- Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
| | - C Hoffmann
- Department of Radiology, University Medical Center Mainz, Mainz, Germany
| | - S Karpuk
- Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
| | - E W Otten
- Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
| | - J Rivoire
- Department of Radiology, Section of Medical Physics, University Medical Center Mainz, Mainz, Germany
| | - Z Salhi
- Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
| | - A Scholz
- Department of Radiology, Section of Medical Physics, University Medical Center Mainz, Mainz, Germany
| | - L M Schreiber
- Department of Radiology, Section of Medical Physics, University Medical Center Mainz, Mainz, Germany
| | - M Terekhov
- Department of Radiology, Section of Medical Physics, University Medical Center Mainz, Mainz, Germany
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18
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Abstract
Lung involvement in cystic fibrosis (CF) disease continues to be a major life-limiting factor of this autosomal recessive genetic disorder. Efforts made toward early diagnosis and advances in therapy have led to sustained survival of affected patients, and many are now of adult age. Because imaging provides detailed information on regional distribution of CF lung disease, repetitive imaging is required for severity assessment and therapy monitoring not only in clinical routine but also for interventional trials. Computed tomography has long succeeded chest radiograph because it provides the highest morphologic detail of airway and parenchymal changes. This is inseparably accompanied by an increase in radiation exposure to CF individuals, who are critically susceptible to, and may accumulate, relevant doses during their lifetime. Magnetic resonance imaging (MRI) as an ionizing radiation-free cross-sectional imaging modality is capable of depicting anatomic hallmarks of CF lung disease at lower spatial resolution but with enhanced tissue characterization. Comprehensive functional lung imaging (imaging of respiratory mechanics, ventilation, and lung perfusion) provides valuable additional information that cannot or can hardly be obtained by any other single diagnostic procedure. The present review article strives to present the current state of lung MRI in CF, as well as its future perspectives. Functional MRI of the CF lung is at the threshold of being considered a routine application, which, supporting early diagnosis, may help to further improve the survival of CF patients.
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Abstract
STUDY DESIGN Retrospective cohort series. OBJECTIVE Characterize average iatrogenic radiation dose to a cohort of children with thoracic insufficiency syndrome (TIS) during assessment and treatment at a single center with vertically expandable prosthetic titanium rib. SUMMARY OF BACKGROUND DATA Children with TIS undergo extensive evaluations to characterize their deformity. No standardized radiographical evaluation exists, but all reports use extensive imaging. The source and level of radiation these patients receive is not currently known. METHODS We evaluated a retrospective consecutive cohort of 62 children who had surgical treatment of TIS at our center from 2001-2011. Typical care included obtaining serial radiographs, spine and chest computed tomographic (CT) scans, ventilation/perfusion scans, and magnetic resonance images. Epochs of treatment were divided into time of initial evaluation to the end of initial vertically expandable prosthetic titanium rib implantation with each subsequent epoch delineated by the next surgical intervention. The effective dose for each examination was estimated within millisieverts (mSv). Plain radiographs were calculated from references. Effective dose was directly estimated for CT scans since 2007 and an average of effective dose from 2007-2011 was used for scans before 2007. Effective dose from fluoroscopy was directly estimated. All doses were reported in mSv. RESULTS A cohort of 62 children had a total of 447 procedures. There were a total of 290 CT scans, 4293 radiographs, 147 magnetic resonance images, and 134 ventilation/perfusion scans. The average accumulated effective dose was 59.6 mSv for children who had completed all treatment, 13.0 mSv up to initial surgery, and 3.2 mSv for each subsequent epoch of treatment. CT scans accounted for 74% of total radiation dose. CONCLUSION Children managed for TIS using a consistent protocol received iatrogenic radiation doses that were on average 4 times the estimated average US background radiation exposure of 3 mSv/yr. CT scans comprised 74% of the total dose. LEVEL OF EVIDENCE 3.
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20
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Advanced functional thoracic imaging in children: from basic concepts to clinical applications. Pediatr Radiol 2013; 43:262-8. [PMID: 23417252 DOI: 10.1007/s00247-012-2466-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 07/09/2012] [Indexed: 10/27/2022]
Abstract
The lungs and airways are organs involved in fairly complex body functions, including ventilation, perfusion, respiratory motion and gas exchange. Imaging evaluation of the pediatric thorax is challenging because involuntary, nonsynchronous respiratory motions and cardiac pulsations degrade image quality appreciably. The extraction of clinically useful functional information from noninvasive imaging methods has been realized even in children thanks to recent technical advancements in thoracic imaging modalities. In this article, advanced functional thoracic imaging techniques in children, focusing on CT and MRI, will be explored from basic concepts to clinical applications.
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21
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Miquel M, Blackall J, Uribe S, Hawkes D, Schaeffter T. Patient-specific respiratory models using dynamic 3D MRI: Preliminary volunteer results. Phys Med 2013; 29:214-20. [DOI: 10.1016/j.ejmp.2012.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 02/24/2012] [Accepted: 03/05/2012] [Indexed: 01/28/2023] Open
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22
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Rubin JM, Feng M, Hadley SW, Fowlkes JB, Hamilton JD. Potential use of ultrasound speckle tracking for motion management during radiotherapy: preliminary report. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2012; 31:469-481. [PMID: 22368138 DOI: 10.7863/jum.2012.31.3.469] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We prospectively evaluated real-time ultrasound speckle tracking for monitoring soft tissue motion for image-guided radiotherapy. Two human volunteers and 1 patient with a proven hepatocellular carcinoma, who was being prepared for radiation therapy treatment, were scanned using a clinical ultrasound scanner modified to acquire and store radiofrequency signals. Scans were performed of the liver in the volunteers and the patient. In the patient, the speckle-tracking results were compared to those measured on a treatment-planning 4-dimensional computed tomogram with tumors contoured manually in each phase and with estimates made by hand on gray scale ultrasound images. The surface of the right lung and the prostate were scanned in a volunteer. The liver and lung surface were scanned during respiration. To simulate prostate motion, the ultrasound probe was rocked in an anterior-posterior direction. The correlation coefficients of all motion measurements were significantly correlated at all sites (P < .00001 for all sites) with 0 time delays. Ultrasound speckle-tracking motion estimates of tumor motion were within 2 mm of estimates made by hand tracking on gray scale ultrasound images and the 4-dimensional computed tomogram. The total tumor motion was greater than 20 mm. The angular displacement of the prostate was within 0.02 radians (1.1°) with displacements measured by hand. Speckle tracking could be used to monitor organ motion during radiotherapy.
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Affiliation(s)
- Jonathan M Rubin
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
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23
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Togao O, Ohno Y, Dimitrov I, Hsia CC, Takahashi M. Ventilation/perfusion imaging of the lung using ultra-short echo time (UTE) MRI in an animal model of pulmonary embolism. J Magn Reson Imaging 2011; 34:539-46. [PMID: 21761465 DOI: 10.1002/jmri.22645] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 04/07/2011] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To test the feasibility of ultra-short echo time (UTE) MRI for assessment of regional pulmonary ventilation/perfusion in a standard 3 Tesla clinical MRI system. MATERIALS AND METHODS MRI of the lungs was conducted with an optimized three-dimensional UTE sequence in normal rats and in a rat model of pulmonary embolism (PE) induced by a blood clot. Changes in signal intensities (SIs) due to inhalation of molecular oxygen or intravenous (i.v.) injection of Gd, which represents the distribution of ventilation and perfusion, respectively, were assessed in the lung parenchyma. RESULTS The UTE MRI with a TE of 100 μs could detect and map the changes in SI of the lung parenchyma due to the inhalation of 100% oxygen or i.v. injection of Gd in normal rats. Reduced T1 resulting from oxygen inhalation was also quantified. These changes were not observed on the images that were obtained simultaneously with a conventional range of TE (2.3 ms). Furthermore, the method could delineate the embolized lesions where the lung ventilation and perfusion were mismatched in a rat model with PE. CONCLUSION These results show the feasibility and diagnostic potential of UTE MRI for the assessment of pulmonary ventilation and perfusion which is essential for the evaluation of a variety of lung diseases.
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Affiliation(s)
- Osamu Togao
- UT Southwestern Medical Center, Dallas, Texas 75390-8542, USA
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24
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Tustison NJ, Cook TS, Song G, Gee JC. Pulmonary kinematics from image data: a review. Acad Radiol 2011; 18:402-17. [PMID: 21377592 DOI: 10.1016/j.acra.2010.10.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 09/02/2010] [Accepted: 10/25/2010] [Indexed: 10/18/2022]
Abstract
The effects of certain lung pathologies include alterations in lung physiology negatively affecting pulmonary compliance. Current approaches to diagnosis and treatment assessment of lung disease commonly rely on pulmonary function testing. Such testing is limited to global measures of lung function, neglecting regional measurements, which are critical for early diagnosis and localization of disease. Increased accessibility to medical image acquisition strategies with high spatiotemporal resolution coupled with the development of sophisticated intensity-based and geometric registration techniques has resulted in the recent exploration of modeling pulmonary motion for calculating local measures of deformation. In this review, the authors provide a broad overview of such research efforts for the estimation of pulmonary deformation. This includes discussion of various techniques, current trends in validation approaches, and the public availability of software and data resources.
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Ventilatory impairment detection based on distribution of respiratory-induced changes in pixel values in dynamic chest radiography: a feasibility study. Int J Comput Assist Radiol Surg 2010; 6:103-10. [PMID: 20549376 DOI: 10.1007/s11548-010-0491-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/17/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE Decreased ventilation is observed on chest radiographs as small changes in X-ray translucency, and ventilatory impairments can therefore be detected by analyzing the distribution of respiratory-induced changes in pixel value. This study was performed to develop a ventilatory impairment detection method based on the distribution of respiratory-induced changes in pixel values. METHODS Sequential chest radiographs during respiration were obtained using a dynamic flat panel detector system. Respiratory-induced changes in pixel value were measured in each local area and then compared for symmetrical positions in both lungs, which were located at the same distance from the axis of the thorax at the same level. The right-left symmetry was assessed in 20 clinical cases (Abnormal, 14; Normal, 6). RESULTS In normal controls, the distribution was symmetrical, and there were good correlations of the pixel value changes in both lungs at symmetrical positions (r = 0.66 ± 0.05). In contrast, abnormal cases did not show a symmetrical distribution of pixel value changes (r = 0.40 ± 0.23) due to ventilation abnormalities observed as reductions in pixel value changes. CONCLUSIONS Ventilatory impairment could be detected as deviation from the right-left symmetry of respiratory-induced changes in pixel value. In particular, the present method could be useful for detecting unilateral abnormalities. However, to detect bilateral abnormalities, further studies are required to develop multilevel detection methods combined with several methods of pattern analysis.
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Dubey RB, Hanmandlu M, Gupta SK, Gupta SK. The brain MR Image segmentation techniques and use of diagnostic packages. Acad Radiol 2010; 17:658-71. [PMID: 20211569 DOI: 10.1016/j.acra.2009.12.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 12/10/2009] [Accepted: 12/12/2009] [Indexed: 11/27/2022]
Abstract
RATIONALE AND OBJECTIVES This article provides a survey of segmentation methods for medical images. Usually, classification of segmentation methods is done based on the approaches adopted and the domain of application. MATERIALS AND METHODS This survey is conducted on the recent segmentation methods used in biomedical image processing and explores the methods useful for better segmentation. A critical appraisal of the current status of semiautomated and automated methods is made for the segmentation of anatomical medical images emphasizing the advantages and disadvantages. Computer-aided diagnosis (CAD) used by radiologists as a second opinion has become one of the major research areas in medical imaging and diagnostic radiology. A picture archiving communication system (PACS) is an integrated workflow system for managing images and related data that is designed to streamline operations throughout the whole patient care delivery process. RESULTS By using PACS, the medical image interpretation may be changed from conventional hard-copy images to soft-copy studies viewed on the systems workstations. CONCLUSION The automatic segmentations assist the doctors in making quick diagnosis. The CAD need not be comparable to that of physicians, but is surely complementary.
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