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Serai SD, Robson MD, Tirkes T, Trout AT. T 1 Mapping of the Abdomen, From the AJR "How We Do It" Special Series. AJR Am J Roentgenol 2024. [PMID: 39194308 DOI: 10.2214/ajr.24.31643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
By exploiting different tissues' characteristic T1 relaxation times, T1-weighted images help distinguish normal and abnormal tissues, aiding assessment of diffuse and local pathologies. However, such images do not provide quantitative T1 values. Advances in abdominal MRI techniques have enabled measurement of abdominal organs' T1 relaxation times, which can be used to create color-coded quantitative maps. T1 mapping is sensitive to tissue microenvironments including inflammation and fibrosis and has received substantial interest for noninvasive imaging of abdominal organ pathology. In particular, quantitative mapping provides a powerful tool for evaluation of diffuse disease by making apparent changes in T1 occurring across organs that may otherwise be difficult to identify. Quantitative measurement also facilitates sensitive monitoring of longitudinal T1 changes. Increased T1 in liver helps to predict parenchymal fibro-inflammation, in pancreas is associated with reduced exocrine function from chronic or autoimmune pancreatitis, and in kidney is associated with impaired renal function and aids diagnosis of chronic kidney disease. In this review, we describe the acquisition, postprocessing, and analysis of T1 maps in the abdomen and explore applications in liver, spleen, pancreas, and kidney. We highlight practical aspects of implementation and standardization, technical pitfalls and confounding factors, and areas of likely greatest clinical impact.
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Affiliation(s)
- Suraj D Serai
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Temel Tirkes
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew T Trout
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Venkatakrishna SSB, Otero HJ, Khrichenko D, Serai SD. Can Automated 3-Dimensional Dixon-Based Methods Be Used in Patients With Liver Iron Overload? J Comput Assist Tomogr 2024; 48:343-353. [PMID: 38595087 DOI: 10.1097/rct.0000000000001574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
PURPOSE Accurate quantification of liver iron concentration (LIC) can be achieved via magnetic resonance imaging (MRI). Maps of liver T2*/R2* are provided by commercially available, vendor-provided, 3-dimensional (3D) multiecho Dixon sequences and allow automated, inline postprocessing, which removes the need for manual curve fitting associated with conventional 2-dimensional (2D) gradient echo (GRE)-based postprocessing. The main goal of our study was to investigate the relationship among LIC estimates generated by 3D multiecho Dixon sequence to values generated by 2D GRE-based R2* relaxometry as the reference standard. METHODS A retrospective review of patients who had undergone MRI scans for estimation of LIC with conventional T2* relaxometry and 3D multiecho Dixon sequences was performed. A 1.5 T scanner was used to acquire the magnetic resonance studies. Acquisition of standard multislice multiecho T2*-based sequences was performed, and R2* values with corresponding LIC were estimated. The comparison between R2* and corresponding LIC estimates obtained by the 2 methods was analyzed via the correlation coefficients and Bland-Altman difference plots. RESULTS This study included 104 patients (51 male and 53 female patients) with 158 MRI scans. The mean age of the patients at the time of scan was 15.2 (SD, 8.8) years. There was a very strong correlation between the 2 LIC estimation methods for LIC values up to 3.2 mg/g (LIC quantitative multiecho Dixon [qDixon; from region of interest R2*] vs LIC GRE [in-house]: r = 0.83, P < 0.01; LIC qDixon [from segmentation volume R2*] vs LIC GRE [in-house]: r = 0.92, P < 0.01); and very weak correlation between the 2 methods at liver iron levels >7 mg/g. CONCLUSION Three-dimensional-based multiecho Dixon technique can accurately measure LIC up to 7 mg/g and has the potential to replace 2D GRE-based relaxometry methods.
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Affiliation(s)
| | | | - Dmitry Khrichenko
- From the Department of Radiology, Children's Hospital of Philadelphia
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Li T, Wang J, Yang Y, Glide-Hurst CK, Wen N, Cai J. Multi-parametric MRI for radiotherapy simulation. Med Phys 2023; 50:5273-5293. [PMID: 36710376 PMCID: PMC10382603 DOI: 10.1002/mp.16256] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 09/10/2022] [Accepted: 12/06/2022] [Indexed: 01/31/2023] Open
Abstract
Magnetic resonance imaging (MRI) has become an important imaging modality in the field of radiotherapy (RT) in the past decade, especially with the development of various novel MRI and image-guidance techniques. In this review article, we will describe recent developments and discuss the applications of multi-parametric MRI (mpMRI) in RT simulation. In this review, mpMRI refers to a general and loose definition which includes various multi-contrast MRI techniques. Specifically, we will focus on the implementation, challenges, and future directions of mpMRI techniques for RT simulation.
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Affiliation(s)
- Tian Li
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jihong Wang
- Department of Radiation Physics, Division of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas, USA
| | - Yingli Yang
- Department of Radiology, Ruijin Hospital, Shanghai Jiaotong Univeristy School of Medicine, Shanghai, China
- SJTU-Ruijing-UIH Institute for Medical Imaging Technology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Carri K Glide-Hurst
- Department of Radiation Oncology, University of Wisconsin, Madison, Wisconsin, USA
| | - Ning Wen
- Department of Radiology, Ruijin Hospital, Shanghai Jiaotong Univeristy School of Medicine, Shanghai, China
- SJTU-Ruijing-UIH Institute for Medical Imaging Technology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- The Global Institute of Future Technology, Shanghai Jiaotong University, Shanghai, China
| | - Jing Cai
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
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Venkatakrishna SSB, Otero HJ, Ghosh A, Khrichenko D, Serai SD. Rate of Change of Liver Iron Content by MR Imaging Methods: A Comparison Study. Tomography 2022; 8:2508-2521. [PMID: 36287808 PMCID: PMC9608976 DOI: 10.3390/tomography8050209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/23/2022] [Accepted: 09/27/2022] [Indexed: 11/05/2022] Open
Abstract
Objective: Magnetic resonance imaging (MRI) can accurately quantify liver iron concentration (LIC), eliminating the need for an invasive liver biopsy. Currently, the most widely used relaxometry methods for iron quantification are R2 and R2*, which are based on T2 and T2* acquisition sequences, respectively. We compared the rate of change of LIC as measured by the R2-based, FDA-approved commercially available third-party software with the rate of change of LIC measured by in-house analysis using R2*-relaxometry-based MR imaging in patients undergoing follow-up MRI scans for liver iron estimation. Methods: We retrospectively included patients who had undergone serial MRIs for liver iron estimation. The MR studies were performed on a 1.5T scanner; standard multi-slice, multi-echo T2- and T2*-based sequences were acquired, and LIC was estimated. The comparison between the rate of change of LIC by R2 and R2* values was performed via correlation coefficients and Bland−Altman difference plots. Results: One hundred and eighty-nine MR abdomen studies for liver iron evaluation from 81 patients (male: 38; female: 43) were included in the study. Fifty-nine patients had two serial scans, eighteen patients had three serial scans, three patients had four serial scans, and one patient had five serial scans. The average time interval between the first and last scans for each patient was 13.3 months. The average rates of change of LIC via R2 and R2* methods were −0.0043 ± 0.0214 and −0.0047 ± 0.012 mg/g per month, respectively. There was no significant difference in the rate of change of LIC observed between the two methods. Linearity between the rate of change of LIC measured by R2 (LIC R2) and R2* (LIC R2*) was strong, showing a correlation coefficient of r = 0.72, p < 0.01. A Bland−Altman plot between the rate of change of the two methods showed that the majority of the plotted variables were between two standard deviations. Conclusion: There was no significant difference in the rate of change of LIC detected between the R2 method and the R2* method that uses a gradient echo (GRE) sequence acquired with breath-hold. Since R2* is relatively faster and less prone to motion artifacts, R2*-derived LIC is recommended for iron homeostasis follow-up in patients with liver iron overload.
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Affiliation(s)
| | - Hansel J. Otero
- Department of Radiology, Children’s Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Adarsh Ghosh
- Department of Radiology, Children’s Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Dmitry Khrichenko
- Department of Radiology, Children’s Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Suraj D. Serai
- Department of Radiology, Children’s Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104, USA
- Correspondence:
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Serai SD. Basics of magnetic resonance imaging and quantitative parameters T1, T2, T2*, T1rho and diffusion-weighted imaging. Pediatr Radiol 2022; 52:217-227. [PMID: 33856502 DOI: 10.1007/s00247-021-05042-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/18/2021] [Accepted: 03/01/2021] [Indexed: 01/27/2023]
Abstract
Magnetic resonance imaging is widely available and accepted as the imaging method of choice for many pediatric body imaging applications. Traditionally, it has been used in a qualitative way, where the images are reported non-numerically by radiologists. But now MRI machines have built-in post-processing software connected to the scanner and the database of MR images. This setting enables and encourages simple quantitative analysis of MR images. In this paper, the author reviews the fundamentals of MRI and discusses the most common quantitative MRI techniques for body imaging: T1, T2, T2*, T1rho and diffusion-weighted imaging (DWI). For each quantitative imaging method, this article reviews the technique, its measurement mechanism, and selected clinical applications to body imaging.
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Affiliation(s)
- Suraj D Serai
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA. .,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
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Sevimli C, Yilmaz Y, Bayramoglu Z, Comert RG, Gul N, Dursun M, Karakas Z. Pancreatic MR imaging and endocrine complications in patients with beta-thalassemia: a single-center experience. Clin Exp Med 2021; 22:95-101. [PMID: 34245399 DOI: 10.1007/s10238-021-00735-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/22/2021] [Indexed: 10/20/2022]
Abstract
Iron deposition in various organs can cause endocrine complications in patients with transfusion-dependent beta-thalassemia. The aim was to investigate the relationship between endocrine complications and pancreatic iron overload using magnetic resonance imaging (MRI). Forty patients with transfusion-dependent thalassemia (TDT) were enrolled in the study. The magnetic resonance imagings of the patients were performed using a 1.5 Tesla Philips MRI scanner. Two out of three patients had at least one clinical endocrine complication. The rate of iron deposition was 62.5% in liver, and 45% in pancreas tissue, and was 12.5% in heart tissue. Pancreatic T2* and hepatic T2* values were significantly positively correlated (p = 0.006). Pancreatic T2* and ferritin were significantly negatively correlated (p = 0.03). Cardiac T2* values were negatively correlated with fasting blood glucose (p = 0.03). Patients with short stature had significantly higher cardiac iron burden (22.3 vs. 36.6 T2*ms; p 0.01), and patients with hypothyroidism had higher liver iron concentrations (9.9 vs. 6.4 LIC mg/g; p = 0.05). The ferritin level of 841 ng/mL and liver iron concentration (LIC) value of 8.7 mg/g were detected as the threshold level for severe pancreatic iron burden (AUC 70%, p:0.04, AUC 80%, p = 0.002, respectively). Moreover, males were found to have decreased pancreas T2* values compared with the values in females (T2* 19.3 vs. 29.9, p = 0.05). Patients with higher ferritin levels over than 840 ng/mL should be closely monitored for pancreatic iron deposition, and patients with endocrine complications should be assessed in terms of cardiac iron burden.
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Affiliation(s)
- Cihangir Sevimli
- Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Yasin Yilmaz
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Institute of Health Sciences, Istanbul, Turkey.
| | - Zuhal Bayramoglu
- Department of Pediatric Radiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Rana Gunoz Comert
- Department of Pediatric Radiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Nurdan Gul
- Department of Internal Medicine, Division of Endocrinology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Memduh Dursun
- Department of Pediatric Radiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Zeynep Karakas
- Department of Pediatrics, Division of Hematology and Oncology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
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Marschall A, Rodriguez Torres D, Rueda Liñares A, Del Castillo Carnevali H, Dejuán Bitriá C, Fraile Sanz C, Duarte Torres J, Álvarez Antón S, Martí Sánchez D. Atrial cholangiocarcinoma diagnosed by cardiac magnetic resonance imaging. Echocardiography 2021; 38:1089-1092. [PMID: 34013545 DOI: 10.1111/echo.15079] [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: 02/09/2021] [Revised: 03/15/2021] [Accepted: 04/26/2021] [Indexed: 11/30/2022] Open
Abstract
In this rare case of intrahepatic cholangiocarcinoma (ICC) tumor thrombus with right atrial (RA) invasion, we describe its diagnostic workup based on cardiac magnetic resonance imaging (cMRI). An 85-year-old man underwent transthoracic echocardiography due to dyspnea, revealing a RA mass. Comprehensive cMRI evaluation, including cine bright blood, T1- and T2-weighed, fat-suppressed, and contrast-enhanced imaging, was performed and diagnosis of ICC tumor thrombus with RA invasion was made. This first description of cMRI-guided diagnosis of RA invasion by ICC tumor thrombus points out the usefulness of cMRI for the diagnostic approach of RA masses suggestive of tumor thrombus.
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Bush AM, Sandino CM, Ramachandran S, Ong F, Dwork N, Zucker EJ, Syed AB, Pauly JM, Alley MT, Vasanawala SS. Rosette Trajectories Enable Ungated, Motion-Robust, Simultaneous Cardiac and Liver T 2 * Iron Assessment. J Magn Reson Imaging 2020; 52:1688-1698. [PMID: 32452088 DOI: 10.1002/jmri.27196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Quantitative T2 * MRI is the standard of care for the assessment of iron overload. However, patient motion corrupts T2 * estimates. PURPOSE To develop and evaluate a motion-robust, simultaneous cardiac and liver T2 * imaging approach using non-Cartesian, rosette sampling and a model-based reconstruction as compared to clinical-standard Cartesian MRI. STUDY TYPE Prospective. PHANTOM/POPULATION Six ferumoxytol-containing phantoms (26-288 μg/mL). Eight healthy subjects and 18 patients referred for clinically indicated iron overload assessment. FIELD STRENGTH/SEQUENCE 1.5T, 2D Cartesian and rosette gradient echo (GRE) ASSESSMENT: GRE T2 * values were validated in ferumoxytol phantoms. In healthy subjects, test-retest and spatial coefficient of variation (CoV) analysis was performed during three breathing conditions. Cartesian and rosette T2 * were compared using correlation and Bland-Altman analysis. Images were rated by three experienced radiologists on a 5-point scale. STATISTICAL TESTS Linear regression, analysis of variance (ANOVA), and paired Student's t-testing were used to compare reproducibility and variability metrics in Cartesian and rosette scans. The Wilcoxon rank test was used to assess reader score comparisons and reader reliability was measured using intraclass correlation analysis. RESULTS Rosette R2* (1/T2 *) was linearly correlated with ferumoxytol concentration (r2 = 1.00) and not significantly different than Cartesian values (P = 0.16). During breath-holding, ungated rosette liver and heart T2 * had lower spatial CoV (liver: 18.4 ± 9.3% Cartesian, 8.8% ± 3.4% rosette, P = 0.02, heart: 37.7% ± 14.3% Cartesian, 13.4% ± 1.7% rosette, P = 0.001) and higher-quality scores (liver: 3.3 [3.0-3.6] Cartesian, 4.7 [4.1-4.9] rosette, P = 0.005, heart: 3.0 [2.3-3] Cartesian, 4.5 [3.8-5.0] rosette, P = 0.005) compared to Cartesian values. During free-breathing and failed breath-holding, Cartesian images had very poor to average image quality with significant artifacts, whereas rosette remained very good, with minimal artifacts (P = 0.001). DATA CONCLUSION Rosette k-sampling with a model-based reconstruction offers a clinically useful motion-robust T2 * mapping approach for iron quantification. J. MAGN. RESON. IMAGING 2020;52:1688-1698.
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Affiliation(s)
- Adam M Bush
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Christopher M Sandino
- Department of Electrical Engineering, Stanford University, Palo Alto, California, USA
| | - Shreya Ramachandran
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, California, USA
| | - Frank Ong
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Nicholas Dwork
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Evan J Zucker
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Ali B Syed
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - John M Pauly
- Department of Electrical Engineering, Stanford University, Palo Alto, California, USA
| | - Marcus T Alley
- Department of Radiology, Stanford University, Palo Alto, California, USA
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Newly Developed Methods for Reducing Motion Artifacts in Pediatric Abdominal MRI: Tips and Pearls. AJR Am J Roentgenol 2020; 214:1042-1053. [PMID: 32023117 DOI: 10.2214/ajr.19.21987] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE. The purpose of this article is to review established and emerging methods for reducing motion artifacts in pediatric abdominal MRI. CONCLUSION. Clearly understanding the strengths and limitations of motion reduction methods can enable practitioners of pediatric abdominal MRI to select and combine the appropriate techniques and potentially reduce the need for sedation and anesthesia.
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