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Wang L, Wang X, Jiang F, Cao Y, Liu S, Chen H, Yang J, Zhang X, Yu T, Xu H, Lin M, Wu Y, Zhang J. Adding quantitative T1rho-weighted imaging to conventional MRI improves specificity and sensitivity for differentiating malignant from benign breast lesions. Magn Reson Imaging 2024; 108:98-103. [PMID: 38331054 DOI: 10.1016/j.mri.2024.02.005] [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: 06/13/2023] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
OBJECTIVES To investigate the feasibility of T1rho-weighted imaging in differentiating malignant from benign breast lesions and to explore the additional value of T1rho to conventional MRI. MATERIALS AND METHODS We prospectively enrolled consecutive women with breast lesions who underwent preoperative T1rho-weighted imaging, diffusion-weighted imaging, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) between November 2021 and July 2023. The T1rho, apparent diffusion coefficient (ADC), and semi-quantitative parameters from DCE-MRI were obtained and compared between benign and malignant groups. The diagnostic performance was analyzed and compared using receiver operating characteristic (ROC) curves and the Delong Test. RESULTS This study included 113 patients (74 malignant and 39 benign lesions). The mean T1rho value in the benign group (92.61 ± 22.10 ms) was significantly higher than that in the malignant group (72.18 ± 16.37 ms) (P < 0.001). The ADC value and time to peak (TTP) value in the malignant group (1.13 ± 0.45 and 269.06 ± 106.01, respectively) were lower than those in the benign group (1.57 ± 0.45 and 388.30 ± 81.13, respectively) (all P < 0.001). T1rho combined with ADC and TTP showed good diagnostic performance with an area under the curve (AUC) of 0.896, a sensitivity of 81.0%, and a specificity of 87.1%. The specificity and sensitivity of the combination of T1rho, ADC, and TTP were significantly higher than those of the combination of ADC and TTP (87.1% vs. 84.6%, P < 0.005; 81.0% vs. 77.0%, P < 0.001). CONCLUSION T1rho-weighted imaging was a feasible MRI sequence for differentiating malignant from benign breast lesions. The combination of T1rho, ADC and TTP could achieve a favorable diagnostic performance with improved specificity and sensitivity, T1rho could serve as a supplementary approach to conventional MRI.
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Affiliation(s)
- Lu Wang
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Xiaoxia Wang
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Fujie Jiang
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Ying Cao
- School of Medicine, Chongqing University, Chongqing 400030, China
| | - Shuling Liu
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Huifang Chen
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Jing Yang
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | | | - Tao Yu
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Hanshan Xu
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Meng Lin
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China
| | - Yongzhong Wu
- Radiation Oncology Center, Chongqing University, Chongqing 400030, China
| | - Jiuquan Zhang
- Department of Radiology, Chongqing University Cancer Hospital, Chongqing Key Laboratory for Intelligent Oncology in Breast Cancer (iCQBC), Chongqing 400030, China.
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Kooreman ES, Tanaka M, ter Beek LC, Peters FP, Marijnen CAM, van der Heide UA, van Houdt PJ. T1ρ for Radiotherapy Treatment Response Monitoring in Rectal Cancer Patients: A Pilot Study. J Clin Med 2022; 11:jcm11071998. [PMID: 35407606 PMCID: PMC8999631 DOI: 10.3390/jcm11071998] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 11/16/2022] Open
Abstract
Quantitative MRI has the potential to produce imaging biomarkers for the prediction of early response to radiotherapy treatment. In this pilot study, a potential imaging biomarker, the T1ρ relaxation time, is assessed for this purpose. A T1ρ sequence was implemented on a 1.5 T MR-linac system, a system that combines an MRI with a linear accelerator for radiation treatment. An agar phantom with concentrations of 1–4% w/w was constructed for technical validation of the sequence. Phantom images were assessed in terms of short-term repeatability and signal-to-noise ratio. Twelve rectal cancer patients, who were treated with 5 × 5 Gy, were imaged on each treatment fraction. Individual changes in the T1ρ values of the gross tumor volume (GTV) showed an increase for most patients, although a paired t-test comparing values in the GTV from the first to the last treatment fraction showed no statistically significant difference. The phantom measurements showed excellent short-term repeatability (0.5–1.5 ms), and phantom T1ρ values corresponded to the literature values. T1ρ imaging was implemented successfully on the MR-linac, with a repeatability comparable to diagnostic systems, although clinical benefit in terms of treatment response monitoring remains to be demonstrated.
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Affiliation(s)
- Ernst S. Kooreman
- Department of Radiation Oncology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; (E.S.K.); (M.T.); (F.P.P.); (C.A.M.M.); (U.A.v.d.H.)
| | - Max Tanaka
- Department of Radiation Oncology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; (E.S.K.); (M.T.); (F.P.P.); (C.A.M.M.); (U.A.v.d.H.)
| | - Leon C. ter Beek
- Department of Radiology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands;
| | - Femke P. Peters
- Department of Radiation Oncology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; (E.S.K.); (M.T.); (F.P.P.); (C.A.M.M.); (U.A.v.d.H.)
| | - Corrie A. M. Marijnen
- Department of Radiation Oncology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; (E.S.K.); (M.T.); (F.P.P.); (C.A.M.M.); (U.A.v.d.H.)
| | - Uulke A. van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; (E.S.K.); (M.T.); (F.P.P.); (C.A.M.M.); (U.A.v.d.H.)
| | - Petra J. van Houdt
- Department of Radiation Oncology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; (E.S.K.); (M.T.); (F.P.P.); (C.A.M.M.); (U.A.v.d.H.)
- Correspondence:
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3
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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: 15] [Impact Index Per Article: 7.5] [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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Takayama Y, Nishie A, Ishimatsu K, Ushijima Y, Fujita N, Kubo Y, Yoshizumi T, Kouhashi KI, Maehara J, Akamine Y, Ishigami K. Diagnostic potential of T1ρ and T2 relaxations in assessing the severity of liver fibrosis and necro-inflammation. Magn Reson Imaging 2022; 87:104-112. [PMID: 34999164 DOI: 10.1016/j.mri.2022.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/20/2021] [Accepted: 01/04/2022] [Indexed: 12/11/2022]
Abstract
PURPOSE To investigate the utility of T1ρ and T2 relaxations for assessing the severity of liver fibrosis (F stage) and necro-inflammation (A stage) in patients with chronic liver disease (CLD). MATERIALS AND METHODS We calculated T1ρ and T2 relaxations of the liver parenchyma in 82 patients who underwent liver surgery. F and A stages of enrolled patients were assessed by referring to surgically resected specimens. The relationships between T1ρ or T2 relaxation and F or A stage were assessed using one-way analysis of variance followed by Tukey's multiple comparison test, Spearman's rank correlation test and a receiver operating characteristic analysis. RESULTS The T1ρ and T2 values of the liver parenchyma were significantly increased as the F and A stages progressed. The T1ρ and T2 values showed significant differences between F0 and F4, between F1 and F4, and between F2 and F4. In addition, T1ρ values showed a significant difference between F0 and F3 as well. The highest diagnostic ability for fibrosis was obtained when differentiating ≥F3 from ≤F2 using T1ρ: the sensitivity was 82.8%, the specificity 79.2% and the area under the curve (AUC) 0.87. The sensitivity and AUC of T1ρ relaxation (46.9% and 0.67) were significantly higher than those of T2 relaxation (29.7% and 0.60) for differentiating ≥A1 from A0. CONCLUSION T1ρ and T2 relaxations have potential as a biochemical marker for assessing the severity of liver fibrosis and necro-inflammation. T1ρ relaxation may be slightly superior to T2 relaxation in terms of diagnostic ability for liver fibrosis and necro-inflammation.
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Affiliation(s)
- Yukihisa Takayama
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Department of Radiology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Akihiro Nishie
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Keisuke Ishimatsu
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yasuhiro Ushijima
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Nobuhiro Fujita
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yuichiro Kubo
- Department of Molecular Imaging and Diagnostic Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tomoharu Yoshizumi
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Ken-Ichi Kouhashi
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Junki Maehara
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yuta Akamine
- Philips Japan. Ltd., Konan 2-13-37, Minato-ku, Tokyo 108-8507, Japan
| | - Kousei Ishigami
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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5
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T1ρ magnetic resonance imaging value as a potential marker to assess the severity of liver fibrosis: A pilot study. Eur J Radiol Open 2021; 8:100321. [PMID: 33490312 PMCID: PMC7806785 DOI: 10.1016/j.ejro.2021.100321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/24/2020] [Accepted: 12/30/2020] [Indexed: 12/24/2022] Open
Abstract
Purpose Assessment of liver fibrosis is essential for the management of liver disease. Although liver biopsy is the gold-standard modality for the diagnosis of liver fibrosis, it has some limitations. Thus, other methods are required to overcome the disadvantages of a liver biopsy. T1ρ magnetic resonance imaging (MRI) values are potential biomarkers for liver cirrhosis. This study aimed to assess the relationship between T1ρ MRI values and liver fibrosis severity by measuring the correlation between T1ρ values and shear wave elastography (SWE) values, which are routinely used for the diagnosis of liver fibrosis. Methods T1ρ imaging and SWE values were obtained from four healthy volunteers and 16 patients with chronic liver disease. The regions of interest on MR images were drawn and matched with those of the right liver lobe on SWE images. Results The mean T1ρ values of the right liver lobe correlated positively with the mean SWE values (Pearson’s correlation coefficient: 0.783; p < 0.0001; 95 % confidence interval: 0.623–0.880). Conclusion The mean T1ρ values of the right liver lobe may be correlated with the severity of liver fibrosis.
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Sogabe T, Ueda H, Ito Y, Taniguchi Y, Kobayashi T. Dependence of stimulus-induced rotary saturation on the direction of target oscillating magnetic fields: A phantom and simulation study. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 321:106849. [PMID: 33128915 DOI: 10.1016/j.jmr.2020.106849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/23/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
Several noninvasive techniques for the direct measurement of the neuronal activity using magnetic resonance imaging (MRI) have recently been reported. As a promising candidate, we focus on a spin-lock MRI sequence (i.e., stimulus-induced rotary saturation (SIRS)) directly measuring a tiny oscillating magnetic field. Previous phantom studies on SIRS have applied the target oscillating magnetic field parallel to the direction of the static magnetic field B0. However, in practice, the neuromagnetic fields are not always aligned in the same direction as in such a condition. This study investigates the MR signal changes during SIRS when the target magnetic field direction is not the same as that of the B0 field through both phantom experiments and Bloch simulations. The experimental results indicate that only the target magnetic field component along the B0 field affects the signal change, indicating that SIRS has partial sensitivity, even if the target magnetic fields are tilted from the B0 field. Furthermore, the simulation results show good agreements with the experimental results. These results clarify the sensitivity direction of SIRS-based fMRI and lead to the possibility that the direction of the generated neuromagnetic fields can be estimated, such that we can separate directional information from the other information contained in neuromagnetic fields (e.g., phase information).
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Affiliation(s)
- Tomoyuki Sogabe
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hiroyuki Ueda
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yosuke Ito
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yo Taniguchi
- Research & Development Group, Hitachi, Ltd., Japan
| | - Tetsuo Kobayashi
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
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7
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Ai QYH, Chen W, So TY, Lam WKJ, Jiang B, Poon DMC, Qamar S, Mo FKF, Blu T, Chan Q, Ma BBY, Hui EP, Chan KCA, King AD. Quantitative T1ρ MRI of the Head and Neck Discriminates Carcinoma and Benign Hyperplasia in the Nasopharynx. AJNR Am J Neuroradiol 2020; 41:2339-2344. [PMID: 33122214 DOI: 10.3174/ajnr.a6828] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 08/07/2020] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE T1ρ imaging is a new quantitative MR imaging pulse sequence with the potential to discriminate between malignant and benign tissue. In this study, we evaluated the capability of T1ρ imaging to characterize tissue by applying T1ρ imaging to malignant and benign tissue in the nasopharynx and to normal tissue in the head and neck. MATERIALS AND METHODS Participants with undifferentiated nasopharyngeal carcinoma and benign hyperplasia of the nasopharynx prospectively underwent T1ρ imaging. T1ρ measurements obtained from the histogram analysis for nasopharyngeal carcinoma in 43 participants were compared with those for benign hyperplasia and for normal tissue (brain, muscle, and parotid glands) in 41 participants using the Mann-Whitney U test. The area under the curve of significant T1ρ measurements was calculated and compared using receiver operating characteristic analysis and the Delong test, respectively. A P < . 05 indicated statistical significance. RESULTS There were significant differences in T1ρ measurements between nasopharyngeal carcinoma and benign hyperplasia and between nasopharyngeal carcinoma and normal tissue (all, P < . 05). Compared with benign hyperplasia, nasopharyngeal carcinoma showed a lower T1ρ mean (62.14 versus 65.45 × ms), SD (12.60 versus 17.73 × ms), and skewness (0.61 versus 0.76) (all P < .05), but no difference in kurtosis (P = . 18). The T1ρ SD showed the highest area under the curve of 0.95 compared with the T1ρ mean (area under the curve = 0.72) and T1ρ skewness (area under the curve = 0.72) for discriminating nasopharyngeal carcinoma and benign hyperplasia (all, P < .05). CONCLUSIONS Quantitative T1ρ imaging has the potential to discriminate malignant from benign and normal tissue in the head and neck.
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Affiliation(s)
- Q Y H Ai
- From the Department of Imaging and Interventional Radiology (Q.Y.H.A., W.C., T.Y.S., B.J., S.Q., A.D.K.)
| | - W Chen
- From the Department of Imaging and Interventional Radiology (Q.Y.H.A., W.C., T.Y.S., B.J., S.Q., A.D.K.)
| | - T Y So
- From the Department of Imaging and Interventional Radiology (Q.Y.H.A., W.C., T.Y.S., B.J., S.Q., A.D.K.)
| | - W K J Lam
- Li Ka Shing Institute of Health Sciences (W.K.J.L., D.M.C.P., B.B.Y.M., E.P.H., K.C.A.C.).,State Key Laboratory of Translational Oncology (W.K.J.L., D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H., K.C.A.C.).,Department of Chemical Pathology (W.K.J.L., K.C.A.C.), State Key Laboratory in Oncology in South China, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR
| | - B Jiang
- From the Department of Imaging and Interventional Radiology (Q.Y.H.A., W.C., T.Y.S., B.J., S.Q., A.D.K.)
| | - D M C Poon
- Li Ka Shing Institute of Health Sciences (W.K.J.L., D.M.C.P., B.B.Y.M., E.P.H., K.C.A.C.).,Department of Clinical Oncology (D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H.), State Key Laboratory in Oncology in South China, Sir Y.K. Pao Centre for Cancer, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, SAR.,State Key Laboratory of Translational Oncology (W.K.J.L., D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H., K.C.A.C.)
| | - S Qamar
- From the Department of Imaging and Interventional Radiology (Q.Y.H.A., W.C., T.Y.S., B.J., S.Q., A.D.K.)
| | - F K F Mo
- Department of Clinical Oncology (D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H.), State Key Laboratory in Oncology in South China, Sir Y.K. Pao Centre for Cancer, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, SAR.,State Key Laboratory of Translational Oncology (W.K.J.L., D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H., K.C.A.C.)
| | - T Blu
- Department of Electrical Engineering (T.B.), The Chinese University of Hong Kong, Hong Kong, SAR
| | - Q Chan
- Philips Healthcare (Q.C.), Hong Kong, SAR
| | - B B Y Ma
- Li Ka Shing Institute of Health Sciences (W.K.J.L., D.M.C.P., B.B.Y.M., E.P.H., K.C.A.C.).,Department of Clinical Oncology (D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H.), State Key Laboratory in Oncology in South China, Sir Y.K. Pao Centre for Cancer, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, SAR.,State Key Laboratory of Translational Oncology (W.K.J.L., D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H., K.C.A.C.)
| | - E P Hui
- Li Ka Shing Institute of Health Sciences (W.K.J.L., D.M.C.P., B.B.Y.M., E.P.H., K.C.A.C.).,Department of Clinical Oncology (D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H.), State Key Laboratory in Oncology in South China, Sir Y.K. Pao Centre for Cancer, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, SAR.,State Key Laboratory of Translational Oncology (W.K.J.L., D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H., K.C.A.C.)
| | - K C A Chan
- Li Ka Shing Institute of Health Sciences (W.K.J.L., D.M.C.P., B.B.Y.M., E.P.H., K.C.A.C.).,State Key Laboratory of Translational Oncology (W.K.J.L., D.M.C.P., F.K.F.M., B.B.Y.M., E.P.H., K.C.A.C.).,Department of Chemical Pathology (W.K.J.L., K.C.A.C.), State Key Laboratory in Oncology in South China, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR
| | - A D King
- From the Department of Imaging and Interventional Radiology (Q.Y.H.A., W.C., T.Y.S., B.J., S.Q., A.D.K.)
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8
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Lyu J, Yang G, Mei Y, Guo L, Guo Y, Zhang X, Xu Y, Feng Y. Non-Gaussian Diffusion Models and T 1 rho Quantification in the Assessment of Hepatic Sinusoidal Obstruction Syndrome in Rats. J Magn Reson Imaging 2020; 52:1110-1121. [PMID: 32246796 DOI: 10.1002/jmri.27156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Non-Gaussian diffusion models and T1 rho quantification may reflect the changes in tissue heterogeneity in hepatic sinusoidal obstruction syndrome (SOS). PURPOSE To investigate the feasibility of diffusion kurtosis imaging (DKI), stretched exponential model (SEM), and T1 rho quantification in detecting and staging SOS in a monocrotaline (MCT)-induced rat model. STUDY TYPE Animal study. POPULATION Thirty male Sprague-Dawley rats gavaged with MCT to induce hepatic SOS and six male rats without any intervention. FIELD STRENGTH/SEQUENCE 3.0T, DWI with five b-values (0-2000 s/mm2 ) and T1 rho with five spin lock times (1-60 msec). ASSESSMENT MRI was performed 1 day before and 1, 3, 5, 7, and 10 days after MCT administration. The corrected apparent diffusion coefficient (Dapp ), kurtosis coefficient (Kapp ), distributed diffusion coefficient (DDC), and intravoxel water molecular diffusion heterogeneity (α) were calculated from the corresponding non-Gaussian diffusion model. The T1 rho value was calculated using a monoexponential model. Specimens obtained from the six timepoints were categorized into normal liver (n = 6), early-stage (n = 16), and late-stage (n = 14) SOS in accordance with the pathological score. STATISTICAL TESTS Parametric statistical methods and receiver operating characteristic (ROC) curves were employed to determine diagnostic accuracy. RESULTS The Dapp , Kapp , DDC, α, and T1 rho values were correlated with pathological score with r values of -0.821, 0.726, -0.828, -0.739, and 0.714 (all P < 0.001), respectively. DKI (combined Dapp and Kapp ) and SEM (combined DDC and α) were better than T1 rho for staging SOS. The areas under the ROC curve of DKI, SEM, and T1 rho for differentiating normal liver and early-stage SOS were 0.97, 1.00, and 0.79, whereas those of DKI, SEM, and T1 rho for differentiating early-stage and late-stage SOS were 1.00, 0.97, and 0.92, respectively. DATA CONCLUSION DKI, SEM, and T1 rho may be helpful in staging SOS. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:1110-1121.
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Affiliation(s)
- Jian Lyu
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong, China
| | - Guixiang Yang
- Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, Guangdong, China
| | - Yingjie Mei
- Philips Healthcare, Guangzhou, Guangdong, China
| | - Li Guo
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong, China.,Department of MRI, The First People's Hospital of Foshan (Affiliated Foshan Hospital of Sun Yat-sen University), Foshan, Guangdong, China
| | - Yihao Guo
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong, China
| | - Xinyuan Zhang
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong, China
| | - Yikai Xu
- Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, Guangdong, China
| | - Yanqiu Feng
- School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, Guangdong, China
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9
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Hectors SJ, Bane O, Stocker D, Carbonell G, Lewis S, Kennedy P, Schiano TD, Thung S, Fischman A, Taouli B. Splenic T 1ρ as a noninvasive biomarker for portal hypertension. J Magn Reson Imaging 2020; 52:787-794. [PMID: 32073207 DOI: 10.1002/jmri.27087] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND There is a need for noninvasive methods for the diagnosis and monitoring of portal hypertension (PH). PURPOSE To 1) assess the correlation of liver and spleen T1 and T1ρ measurements with portal pressures in patients with chronic liver disease, and 2) to compare the diagnostic performance of the relaxation parameters with radiological assessment of PH. STUDY TYPE Prospective. SUBJECTS Twenty-five patients (M/F 16/9, mean age 56 years, range 21-78 years) undergoing portal pressure (hepatic venous pressure gradient [HVPG]) measurements. FIELD STRENGTH/SEQUENCE 1.5T abdominal MRI scan, including T1ρ and T1 mapping. ASSESSMENT Liver and spleen T1ρ and T1 , radiological PH score, and (normalized) spleen length were evaluated. STATISTICAL TESTS Spearman correlation of all MRI parameters with HVPG was assessed. The diagnostic performance of the assessed parameters for prediction of PH (HVPG ≥5 mmHg) and clinically significant PH (CSPH, HVPG ≥10 mmHg) was determined by receiver operating characteristic (ROC) analysis. RESULTS The mean HVPG measurement was 7.8 ± 5.3 mmHg (PH, n = 18 [72%] including CSPH, n = 9 [36%]). PH score, (normalized) spleen length and spleen T1ρ significantly correlated with HVPG, with the strongest correlation found for spleen T1ρ (r = 0.613, P = 0.001). Spleen T1ρ was the only parameter that showed significant diagnostic performance for assessment of PH (area under the curve [AUC] 0.817, P = 0.015) and CSPH (AUC = 0.778, P = 0.024). Normalized spleen length also showed significant diagnostic performance for prediction of CSPH, with a slightly lower AUC (= 0.764, P = 0.031). The radiological PH score, T1ρ and T1 of the liver and T1 of the spleen, did not show significant diagnostic performance for assessment of CSPH (P > 0.075). DATA CONCLUSION Spleen T1ρ showed a significant correlation with portal pressure and showed improved diagnostic performance for prediction of CSPH compared to radiological assessment. These initial results need confirmation in a larger cohort. LEVEL OF EVIDENCE 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;52:787-794.
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Affiliation(s)
- Stefanie J Hectors
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Weill Cornell Medicine, New York, New York, USA
| | - Octavia Bane
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Daniel Stocker
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Institute of Interventional and Diagnostic Radiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Guillermo Carbonell
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Virgen de la Arrixaca University Clinical Hospital, University of Murcia, Murcia, Spain
| | - Sara Lewis
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Paul Kennedy
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Thomas D Schiano
- Recanati/Miller Transplantation Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Swan Thung
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Aaron Fischman
- Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Bachir Taouli
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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10
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Xie S, Qi H, Li Q, Zhang K, Zhang L, Cheng Y, Shen W. Liver injury monitoring, fibrosis staging and inflammation grading using T1rho magnetic resonance imaging: an experimental study in rats with carbon tetrachloride intoxication. BMC Gastroenterol 2020; 20:14. [PMID: 31941457 PMCID: PMC6964054 DOI: 10.1186/s12876-020-1161-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 01/06/2020] [Indexed: 12/30/2022] Open
Abstract
Background To investigate the merit of T1rho relaxation for the evaluation of liver fibrosis, inflammatory activity, and liver injury monitoring in a carbon tetrachloride (CCl4)-induced rat model. Methods Model rats from CCl4-induced liver fibrosis (fibrosis group: n = 41; regression group: n = 20) and control (n = 11) groups underwent black blood T1rho magnetic resonance (MR) imaging (MRI). Injection of CCl4 was done twice weekly for up to 12 weeks in the fibrosis group and for up to 6 weeks in the regression group. MR scanning time points were at baseline and at 2, 4, 6, 8, 10 and 12 weeks after CCl4 injection in the fibrosis group and at baseline and at 2, 4, 6 (CCl4 withdrawal), 7, 8, 10 and 12 weeks in the regression group. Results In the fibrosis group, liver T1rho values increased gradually within week 8 and then decreased. In the regression group, T1rho values dropped gradually after the withdrawal of CCl4 and fell below those at baseline. The T1rho values at S0 were lower than those at any other stage (all P < 0.05). The T1rho values at G0 were significantly lower than those at any other grade, and G1 was lower than G2 (all P < 0.01). The T1rho values mildly correlated with fibrosis stages (r = 0.362) and moderately correlated with grades of inflammation (r = 0.568). The T1rho values of rats with the same inflammation grades showed no significant difference among different fibrosis stages, and the T1rho values at S3 showed a significant difference among different grades of inflammation (P = 0.024). Inflammation grade was an independent variable associated with T1rho values (P < 0.001). Conclusion T1rho MRI can be used to monitor CCl4-induced liver injury, and inflammatory activity had a greater impact on liver T1rho values than fibrosis.
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Affiliation(s)
- Shuangshuang Xie
- Department of Radiology, First Central Hospital Clinical Institute, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, 300070, China
| | - Hanxiong Qi
- Department of Radiology, Tianjin First Central Hospital, Tianjin medical imaging institute, 24 Fukang Road, Nankai District, Tianjin, 300192, China
| | - Qing Li
- Department of Radiology, Tianjin First Central Hospital, Tianjin medical imaging institute, 24 Fukang Road, Nankai District, Tianjin, 300192, China
| | - Kun Zhang
- Department of Radiology, Tianjin First Central Hospital, Tianjin medical imaging institute, 24 Fukang Road, Nankai District, Tianjin, 300192, China
| | - Longjiang Zhang
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, 305 Zhongshan East Road, Nanjing, 210002, Jiangsu, China
| | - Yue Cheng
- Department of Radiology, Tianjin First Central Hospital, Tianjin medical imaging institute, 24 Fukang Road, Nankai District, Tianjin, 300192, China
| | - Wen Shen
- Department of Radiology, Tianjin First Central Hospital, Tianjin medical imaging institute, 24 Fukang Road, Nankai District, Tianjin, 300192, China.
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11
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Zu Z, Janve V, Gore JC. Spin-lock imaging of intrinsic susceptibility gradients in tumors. Magn Reson Med 2019; 83:1587-1595. [PMID: 31883149 DOI: 10.1002/mrm.28155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 12/07/2019] [Accepted: 12/11/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE Previous studies have shown that diffusion of water through intrinsic susceptibility gradients produces a dispersion of the spin-lattice relaxation rate in the rotating frame (R1 ρ ) over a low range of spin-locking amplitudes (0 < ω1 < 100 Hz), whereas at higher ω1 and high magnetic fields, a second dispersion arises due to chemical exchange. Here, we separated these different effects and evaluated their contributions in tumors. METHODS Maps of R1 ρ and its changes with locking field were acquired on intracranial 9-L tumor models. The R1 ρ changes due to diffusion ( R 1 ρ Diff ) were calculated by subtracting maps of R1 ρ at 100 Hz (R1 ρ [100 Hz]) from those at 0 Hz (R1 ρ [0 Hz]). The R1 ρ changes due to exchange ( R 1 ρ Ex ) were calculated by subtracting maps of R1 ρ at 5620 Hz (R1 ρ [5620 Hz]) from those of R1 ρ at 100 Hz (R1 ρ [100 Hz]). Measurements of vascular dimensions and spacing were performed ex vivo using 3D confocal microscopy. RESULTS The R1 ρ changes at low ω1 in tumors (5.24 ± 1.78 s-1 ) are substantially (p = 3.76 ) greater than those in normal tissues (1.36 ± 0.70 s-1 ), which we suggest are due to greater contributions from diffusion through susceptibility gradients. Tumor vessels were larger and spaced less closely compared with normal brain, which may be 1 factor contributing the susceptibility within 9-L tumors. The contrast between tumor and normal tissues for R 1 ρ Diff is larger than for R 1 ρ Ex and for the apparent R2w . CONCLUSION Images that are sensitive to the variations of spin-lock relaxation rates at low ω1 provide a novel form of contrast that reflects the heterogeneous nature of intrinsic variations within tumors.
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Affiliation(s)
- Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Vaibhav Janve
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
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12
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Hectors SJ, Bane O, Kennedy P, El Salem F, Menon M, Segall M, Khaim R, Delaney V, Lewis S, Taouli B. T 1ρ mapping for assessment of renal allograft fibrosis. J Magn Reson Imaging 2019; 50:1085-1091. [PMID: 30666744 DOI: 10.1002/jmri.26656] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND There is an unmet need for noninvasive methods to diagnose and stage renal allograft fibrosis. PURPOSE To investigate the utility of T1ρ measured with MRI for the assessment of fibrosis in renal allografts. STUDY TYPE Institutional Review Board (IRB)-approved prospective. SUBJECTS Fifteen patients with stable functional allograft (M/F 9/6, mean age 56 years) and 12 patients with allograft dysfunction and established fibrosis (M/F 6/6, mean age 51 years). FIELD STRENGTH/SEQUENCE T1ρ imaging at 1.5T using a custom-developed sequence. ASSESSMENT Average T1ρ in the cortex and medulla was quantified and T1ρ repeatability (expressed by the coefficient of variation [CV]) was measured in four patients. STATISTICAL TESTS Differences in T1ρ values between the 2 groups were assessed using Mann-Whitney U-tests. Diagnostic performance of T1ρ for differentiation between functional and fibrotic allografts was evaluated using receiver operating characteristic (ROC) analysis. Spearman correlations of T1ρ with Masson's trichrome-stained fractions and serum estimated glomerular filtration rate (eGFR) were assessed. RESULTS Higher T1ρ repeatability was found for cortex compared with medulla (mean CV T1ρ cortex 7.4%, medulla 13.3%). T1ρ values were significantly higher in the cortex of fibrotic vs. functional allografts (111.8 ± 17.2 msec vs. 99.0 ± 11.0 msec, P = 0.027), while there was no difference in medullary T1ρ values (122.6 ± 20.8 msec vs. 124.3 ± 20.8 msec, P = 0.789). Cortical T1ρ significantly correlated with Masson's trichrome-stained fractions (r = 0.515, P = 0.044) and eGFR (r = -0.546, P = 0.004), and demonstrated an area under the curve (AUC) of 0.77 for differentiating between functional and fibrotic allografts (sensitivity and specificity of 75.0% and 86.7%, using threshold of 106.9 msec). DATA CONCLUSION Our preliminary results suggest that T1ρ is a potential imaging biomarker of renal allograft fibrosis. These results should be verified in a larger study. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1085-1091.
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Affiliation(s)
- Stefanie J Hectors
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Octavia Bane
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Paul Kennedy
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Fadi El Salem
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Madhav Menon
- Division of Renal Medicine, Recanati Miller Transplantation Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Maxwell Segall
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Rafael Khaim
- Division of Renal Medicine, Recanati Miller Transplantation Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Veronica Delaney
- Division of Renal Medicine, Recanati Miller Transplantation Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Sara Lewis
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Bachir Taouli
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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13
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Xie S, Li Q, Cheng Y, Zhang Y, Zhuo Z, Zhao G, Shen W. Impact of Liver Fibrosis and Fatty Liver on T1rho Measurements: A Prospective Study. Korean J Radiol 2017; 18:898-905. [PMID: 29089822 PMCID: PMC5639155 DOI: 10.3348/kjr.2017.18.6.898] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 04/15/2017] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE To investigate the liver T1rho values for detecting fibrosis, and the potential impact of fatty liver on T1rho measurements. MATERIALS AND METHODS This study included 18 healthy subjects, 18 patients with fatty liver, and 18 patients with liver fibrosis, who underwent T1rho MRI and mDIXON collections. Liver T1rho, proton density fat fraction (PDFF) and T2* values were measured and compared among the three groups. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the T1rho values for detecting liver fibrosis. Liver T1rho values were correlated with PDFF, T2* values and clinical data. RESULTS Liver T1rho and PDFF values were significantly different (p < 0.001), whereas the T2* (p = 0.766) values were similar, among the three groups. Mean liver T1rho values in the fibrotic group (52.6 ± 6.8 ms) were significantly higher than those of healthy subjects (44.9 ± 2.8 ms, p < 0.001) and fatty liver group (45.0 ± 3.5 ms, p < 0.001). Mean liver T1rho values were similar between healthy subjects and fatty liver group (p = 0.999). PDFF values in the fatty liver group (16.07 ± 10.59%) were significantly higher than those of healthy subjects (1.43 ± 1.36%, p < 0.001) and fibrosis group (1.07 ± 1.06%, p < 0.001). PDFF values were similar in healthy subjects and fibrosis group (p = 0.984). Mean T1rho values performed well to detect fibrosis at a threshold of 49.5 ms (area under the ROC curve, 0.855), had a moderate correlation with liver stiffness (r = 0.671, p = 0.012), and no correlation with PDFF, T2* values, subject age, or body mass index (p > 0.05). CONCLUSION T1rho MRI is useful for noninvasive detection of liver fibrosis, and may not be affected with the presence of fatty liver.
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Affiliation(s)
- Shuangshuang Xie
- Department of Radiology, Tianjin First Center Hospital, Tianjin 300192, China
| | - Qing Li
- Department of Radiology, Tianjin First Center Hospital, Tianjin 300192, China
| | - Yue Cheng
- Department of Radiology, Tianjin First Center Hospital, Tianjin 300192, China
| | - Yu Zhang
- Clinical Science, Philips Healthcare, Beijing 100600, China
| | - Zhizheng Zhuo
- Clinical Science, Philips Healthcare, Beijing 100600, China
| | - Guiming Zhao
- Department of Hepatology, Tianjin Second People's Hospital, Tianjin 300192, China
| | - Wen Shen
- Department of Radiology, Tianjin First Center Hospital, Tianjin 300192, China
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14
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Dong H, Hwang SM, Wendland M, You L, Clarke J, Inglis B. Ultralow-field and spin-locking relaxation dispersion in postmortem pig brain. Magn Reson Med 2017; 78:2342-2351. [PMID: 28164366 DOI: 10.1002/mrm.26621] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 11/28/2016] [Accepted: 01/02/2017] [Indexed: 11/08/2022]
Abstract
PURPOSE To investigate tissue-specific differences, a quantitative comparison was made between relaxation dispersion in postmortem pig brain measured at ultralow fields (ULF) and spin locking at 7 tesla (T). The goal was to determine whether ULF-MRI has potential advantages for in vivo human brain imaging. METHODS Separate specimens of gray matter and white matter were investigated using an ULF-MRI system with superconducting quantum interference device (SQUID) signal detection to measure T1ULF at fields from 58.7 to 235.0 μT and using a commercial MRI scanner to measure T1ρ7T at spin-locking fields from 5.0 to 235.0 μT. RESULTS At matched field strengths, T1ρ7T is 50 to 100% longer than T1ULF. Furthermore, dispersion in T1ULF is close to linear between 58.7 and 235 µT, whereas dispersion in T1ρ7T is highly nonlinear over the same range. A subtle elbow in the T1ULF dispersion at approximately 140 µT is tentatively attributed to the local dipolar field of macromolecules. It is suggested that different relaxation mechanisms dominate each method and that ULF-MRI has a fundamentally different sensitivity to the macromolecular structure of neural tissue. CONCLUSIONS Ultralow-field MRI may offer distinct, quantitative advantages for human brain imaging, while simultaneously avoiding the severe heating limitation imposed on high-field spin locking. Magn Reson Med 78:2342-2351, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hui Dong
- Department of Physics, University of California, Berkeley, California, USA.,State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences (CAS), Shanghai, China.,CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Shanghai, China
| | - Seong-Min Hwang
- Department of Physics, University of California, Berkeley, California, USA.,Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Michael Wendland
- Berkeley Preclinical Imaging Core (BPIC) Facility, University of California, Berkeley, California, USA
| | - Lixing You
- Department of Physics, University of California, Berkeley, California, USA.,State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences (CAS), Shanghai, China.,CAS Center for ExcelleNce in Superconducting Electronics (CENSE), Shanghai, China
| | - John Clarke
- Department of Physics, University of California, Berkeley, California, USA
| | - Ben Inglis
- Henry H. Wheeler, Jr. Brain Imaging Center (BIC), University of California, Berkeley, California, USA
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15
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Early Changes of Irradiated Parotid Glands Evaluated by T1rho-Weighted Imaging. J Comput Assist Tomogr 2017; 41:472-476. [DOI: 10.1097/rct.0000000000000547] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Zhang H, Yang Q, Yu T, Chen X, Huang J, Tan C, Liang B, Guo H. Comparison of T2, T1rho, and diffusion metrics in assessment of liver fibrosis in rats. J Magn Reson Imaging 2016; 45:741-750. [PMID: 27527587 DOI: 10.1002/jmri.25424] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/02/2016] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To evaluate the value of T2 , T1 rho, and diffusion metrics in assessment of liver fibrosis in rats. MATERIALS AND METHODS Liver fibrosis in a rat model (n = 72) was induced by injection of carbon tetrachloride (CCl4 ) at 3T. T2 , T1 rho, and diffusion parameters (apparent diffusion coefficient (ADC), Dtrue ) via spin echo (SE) diffusion-weighted imaging (DWI) and stimulated echo acquisition mode (STEAM) DWI with three diffusion times (DT: 80, 106, 186 msec) were obtained in surviving rats with hepatic fibrosis (n = 52) and controls (n = 8). Liver fibrosis stage (F0-F6) was identified based on pathological results using the traditional liver fibrosis staging method for rodents. Nonparametric statistical methods and receiver operating characteristic (ROC) curve analysis were employed to determine the diagnostic accuracy. RESULTS Mean T2 , T1 rho, ADC, and Dtrue with DT = 186 msec correlated with the severity of fibrosis with r = 0.73, 0.83, -0.83, and -0.85 (all P < 0.001), respectively. The average areas under the ROC curve at different stages for T1 rho and diffusion parameters (DT = 186 msec) were larger than those of T2 and SE DWI (0.92, 0.92, and 0.92 vs. 0.86, 0.82, and 0.83). The corresponding average sensitivity and specificity for T1 rho and diffusion parameters with a long DT were larger (89.35 and 88.90, 88.36 and 89.97, 90.16 and 87.13) than T2 and SE DWI (90.28 and 79.93, 85.30 and 77.64, 78.21 and 82.41). The performances of T1 rho and Dtrue (DT = 186 msec) were comparable (average AUC: 0.92 and 0.92). CONCLUSION Among the evaluated sequences, T1 rho and STEAM DWI with a long DT may serve as superior imaging biomarkers for assessing liver fibrosis and monitoring disease severity. LEVEL OF EVIDENCE 1 J. Magn. Reson. Imaging 2017;45:741-750.
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Affiliation(s)
- Hui Zhang
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, Beijing, China
| | - Qihua Yang
- Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Taihui Yu
- Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaodong Chen
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, Beijing, China.,Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.,Department of Radiology, Affiliated hospital of Guangdong Medical College, Guangdong, China
| | - Jingwen Huang
- Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Cui Tan
- Department of Pathology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Biling Liang
- Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Hua Guo
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, Beijing, China
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17
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Schuenke P, Koehler C, Korzowski A, Windschuh J, Bachert P, Ladd ME, Mundiyanapurath S, Paech D, Bickelhaupt S, Bonekamp D, Schlemmer HP, Radbruch A, Zaiss M. Adiabatically prepared spin-lock approach for T1ρ-based dynamic glucose enhanced MRI at ultrahigh fields. Magn Reson Med 2016; 78:215-225. [DOI: 10.1002/mrm.26370] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/12/2016] [Accepted: 07/14/2016] [Indexed: 12/23/2022]
Affiliation(s)
- Patrick Schuenke
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Christina Koehler
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | - Andreas Korzowski
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Johannes Windschuh
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Peter Bachert
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Mark E. Ladd
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | | | - Daniel Paech
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | | | - David Bonekamp
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | | | - Alexander Radbruch
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | - Moritz Zaiss
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
- Max-Planck-Institute for Biological Cybernetics; Tübingen Baden-Württemberg Germany
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18
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Mitrea BG, Krafft AJ, Song R, Loeffler RB, Hillenbrand CM. Paired self-compensated spin-lock preparation for improved T1ρ quantification. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 268:49-57. [PMID: 27161095 DOI: 10.1016/j.jmr.2016.04.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 04/28/2016] [Accepted: 04/29/2016] [Indexed: 06/05/2023]
Abstract
PURPOSE Spin-lock (SL) imaging allows quantification of the spin-lattice relaxation time in the rotating frame (T1ρ). B0 and B1 inhomogeneities impact T1ρ quantification because the preparatory block in SL imaging is sensitive to the field heterogeneities. Here, a modified preparatory block (PSC-SL) is proposed that attempts to alleviate SL sensitivity to field inhomogeneities in scenarios where existing approaches fail, i.e. high SL frequencies. METHODS Computer simulations, phantom and in vivo experiments were used to determine the effect of field inhomogeneities on T1ρ quantification. Existing SL preparations were compared with PSC-SL in different conditions to assess the advantages and disadvantages of each method. RESULTS Phantom experiments and computer modeling demonstrate that PSC-SL provides superior T1ρ quantification at high SL frequencies in situations where the existing SL preparation methods fail. This result has been confirmed in pre-clinical neuro and body imaging at 7T. CONCLUSION PSC-SL complements existing methods by increasing the accuracy of T1ρ quantification at high spin-lock frequencies when large field inhomogeneities are present. A-priory information about the experimental conditions such, as field distribution and spinlock frequency are useful for selecting an appropriate spin-lock preparation for specific applications.
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Affiliation(s)
- Bogdan G Mitrea
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Axel J Krafft
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Ruitian Song
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Ralf B Loeffler
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Claudia M Hillenbrand
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA.
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19
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Gilani IA, Sepponen R. Quantitative rotating frame relaxometry methods in MRI. NMR IN BIOMEDICINE 2016; 29:841-861. [PMID: 27100142 DOI: 10.1002/nbm.3518] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 01/21/2016] [Accepted: 02/18/2016] [Indexed: 06/05/2023]
Abstract
Macromolecular degeneration and biochemical changes in tissue can be quantified using rotating frame relaxometry in MRI. It has been shown in several studies that the rotating frame longitudinal relaxation rate constant (R1ρ ) and the rotating frame transverse relaxation rate constant (R2ρ ) are sensitive biomarkers of phenomena at the cellular level. In this comprehensive review, existing MRI methods for probing the biophysical mechanisms that affect the rotating frame relaxation rates of the tissue (i.e. R1ρ and R2ρ ) are presented. Long acquisition times and high radiofrequency (RF) energy deposition into tissue during the process of spin-locking in rotating frame relaxometry are the major barriers to the establishment of these relaxation contrasts at high magnetic fields. Therefore, clinical applications of R1ρ and R2ρ MRI using on- or off-resonance RF excitation methods remain challenging. Accordingly, this review describes the theoretical and experimental approaches to the design of hard RF pulse cluster- and adiabatic RF pulse-based excitation schemes for accurate and precise measurements of R1ρ and R2ρ . The merits and drawbacks of different MRI acquisition strategies for quantitative relaxation rate measurement in the rotating frame regime are reviewed. In addition, this review summarizes current clinical applications of rotating frame MRI sequences. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Irtiza Ali Gilani
- Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University, Aalto, Finland
- Advanced Magnetic Imaging Center, Aalto University, Aalto, Finland
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Raimo Sepponen
- Department of Electronics, School of Electrical Engineering, Aalto University, Aalto, Finland
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20
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Yang Q, Yu T, Yun S, Zhang H, Chen X, Cheng Z, Zhong J, Huang J, Okuaki T, Chan Q, Liang B, Guo H. Comparison of multislice breath-hold and 3D respiratory triggeredT1ρ imaging of liver in healthy volunteers and liver cirrhosis patients in 3.0 T MRI. J Magn Reson Imaging 2016; 44:906-13. [PMID: 27149283 DOI: 10.1002/jmri.25253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 03/06/2016] [Indexed: 01/09/2023] Open
Affiliation(s)
- Qihua Yang
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Taihui Yu
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Su Yun
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Hui Zhang
- Center for Biomedical Imaging Research; Department of Biomedical Engineering; Tsinghua University; Beijing China
| | - Xiaodong Chen
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Ziliang Cheng
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Jinglian Zhong
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Jingwen Huang
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | | | | | - Biling Liang
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Hua Guo
- Center for Biomedical Imaging Research; Department of Biomedical Engineering; Tsinghua University; Beijing China
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21
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Abstract
The spin-lattice relaxation time constant in rotating frame (T1rho) is useful for assessment of the properties of macromolecular environment inside tissue. Quantification of T1rho is found promising in various clinical applications. However, T1rho imaging is prone to image artifacts and quantification errors, which remains one of the greatest challenges to adopt this technique in routine clinical practice. The conventional continuous wave spin-lock is susceptible to B1 radiofrequency (RF) and B0 field inhomogeneity, which appears as banding artifacts in acquired images. A number of methods have been reported to modify T1rho prep RF pulse cluster to mitigate this effect. Adiabatic RF pulse can also be used for spin-lock with insensitivity to both B1 RF and B0 field inhomogeneity. Another source of quantification error in T1rho imaging is signal evolution during imaging data acquisition. Care is needed to affirm such error does not take place when specific pulse sequence is used for imaging data acquisition. Another source of T1rho quantification error is insufficient signal-to-noise ratio (SNR), which is common among various quantitative imaging approaches. Measurement of T1rho within an ROI can mitigate this issue, but at the cost of reduced resolution. Noise-corrected methods are reported to address this issue in pixel-wise quantification. For certain tissue type, T1rho quantification can be confounded by magic angle effect and the presence of multiple tissue components. Review of these confounding factors from inherent tissue properties is not included in this article.
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Affiliation(s)
- Weitian Chen
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China
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22
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Moonen RPM, van der Tol P, Hectors SJCG, Starmans LWE, Nicolay K, Strijkers GJ. Spin-lock MR enhances the detection sensitivity of superparamagnetic iron oxide particles. Magn Reson Med 2014; 74:1740-9. [PMID: 25470118 DOI: 10.1002/mrm.25544] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 10/14/2014] [Accepted: 11/03/2014] [Indexed: 11/10/2022]
Abstract
PURPOSE To evaluate spin-lock MR for detecting superparamagnetic iron oxides and compare the detection sensitivity of quantitative T1ρ with T2 imaging. METHODS In vitro experiments were performed to investigate the influence of iron oxide particle size and composition on T1ρ . These comprise T1ρ and T2 measurements (B0 = 1.41T) of agar (2%) with concentration ranges of three different iron oxide nanoparticles (IONs) (Sinerem, Resovist, and ION-Micelle) and microparticles of iron oxide (MPIO). T1ρ dispersion was measured for a range of spin-lock amplitudes (γB1 = 6.5-91 kHz). Under relevant in vivo conditions (B0 = 9.4T; γB1 = 100-1500 Hz), T1ρ and T2 mapping of the liver was performed in seven mice pre- and 24 h postinjection of Sinerem. RESULTS Addition of iron oxide nanoparticles decreased T1ρ as well as the native T1ρ dispersion of agar, leading to increased contrast at high spin-lock amplitudes. Changes of T1ρ were highly linear with iron concentration and much larger than T2 changes. MPIO did not show this effect. In vivo, a decrease of T1ρ was observed with no clear influence on T1ρ dispersion. CONCLUSION By suppression of T1ρ dispersion, iron oxide nanoparticles cause enhanced T1ρ contrast compared to T2 . The underlying mechanism appears to be loss of lock. Spin-lock MR is therefore a promising technique for sensitive detection of iron oxide contrast agents.
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Affiliation(s)
- Rik P M Moonen
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Pieternel van der Tol
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Stefanie J C G Hectors
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Lucas W E Starmans
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Gustav J Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
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23
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Takayama Y, Nishie A, Asayama Y, Ushijima Y, Okamoto D, Fujita N, Morita K, Shirabe K, Kotoh K, Kubo Y, Okuaki T, Honda H. T1ρ Relaxation of the liver: A potential biomarker of liver function. J Magn Reson Imaging 2014; 42:188-95. [DOI: 10.1002/jmri.24739] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/12/2014] [Indexed: 01/20/2023] Open
Affiliation(s)
- Yukihisa Takayama
- Department of Radiology Informatics and Network; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Akihiro Nishie
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Yoshiki Asayama
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Yasuhiro Ushijima
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Daisuke Okamoto
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Nobuhiro Fujita
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Koichiro Morita
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Ken Shirabe
- Department of Surgery and Science; Graduate School of Medical Sciences, Kyushu University; 3-1-1 Fukuoka Japan
| | - Kazuhiro Kotoh
- Department of Medicine and Bioregulatory Science; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Yuichiro Kubo
- Department of Anatomic Pathology, Pathological Sciences; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | | | - Hiroshi Honda
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
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24
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Wang L, Regatte RR. T₁ρ MRI of human musculoskeletal system. J Magn Reson Imaging 2014; 41:586-600. [PMID: 24935818 DOI: 10.1002/jmri.24677] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 06/03/2014] [Indexed: 12/21/2022] Open
Abstract
Magnetic resonance imaging (MRI) offers the direct visualization of the human musculoskeletal (MSK) system, especially all diarthrodial tissues including cartilage, bone, menisci, ligaments, tendon, hip, synovium, etc. Conventional MRI techniques based on T1 - and T2 -weighted, proton density (PD) contrast are inconclusive in quantifying early biochemically degenerative changes in MSK system in general and articular cartilage in particular. In recent years, quantitative MR parameter mapping techniques have been used to quantify the biochemical changes in articular cartilage, with a special emphasis on evaluating joint injury, cartilage degeneration, and soft tissue repair. In this article we focus on cartilage biochemical composition, basic principles of T1ρ MRI, implementation of T1ρ pulse sequences, biochemical validation, and summarize the potential applications of the T1ρ MRI technique in MSK diseases including osteoarthritis (OA), anterior cruciate ligament (ACL) injury, and knee joint repair. Finally, we also review the potential advantages, challenges, and future prospects of T1ρ MRI for widespread clinical translation.
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Affiliation(s)
- Ligong Wang
- Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, Jiangsu, China
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25
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T1ρ magnetic resonance imaging for detection of early cartilage changes in knees of asymptomatic collegiate female impact and nonimpact athletes. Clin J Sport Med 2014; 24:218-25. [PMID: 24172654 PMCID: PMC6425943 DOI: 10.1097/jsm.0000000000000013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine if T1ρ magnetic resonance imaging (T1ρ MRI) could assess early articular cartilage changes in knees of asymptomatic female collegiate athletes. It was hypothesized that impact cohort would demonstrate greater changes than nonimpact cohort. DESIGN An institutional review board-approved prospective cohort study. Blinded MRI analyses. SETTING Participants from collegiate athletic program. Imaging at university hospital, February 2008 to July 2009. PARTICIPANTS Inclusion criteria were female collegiate athletes in athletic season and asymptomatic. Exclusion criteria were previous/current knee injuries/surgeries. Twenty-one female NCAA Division I athletes, 11 impact (basketball players) and 10 nonimpact (swimmers) participants were consented and imaged with 3.0-T MRI (Siemens) and T1ρ sequence (University of Pennsylvania). One patient was removed (injury diagnosis). Final roster was 10 impact and 10 nonimpact participants. No difference in cohort body mass index, height, or weight. MAIN OUTCOME MEASURES Average T1ρ relaxation times (ART) for patellar and femoral cartilage to analyze defined regions and depth and modified International Cartilage Repair Society classification. RESULTS Statistical analyses showed that ART of radial zone of central third weight-bearing region of cartilage in basketball players was significantly greater (P = 0.041) than swimmers and ART of the superficial zone in basketball players was significantly less (P = 0.003) than that of swimmers. For both groups, the ART of superficial zones were significantly greater than that of radial zones (P < 0.001). Four impact athletes showed macroscopic changes (none in nonimpact cohort). CONCLUSIONS T1ρ MRI detected early changes in articular cartilage of asymptomatic collegiate female impact athletes, with significant differences between cohorts in radial zone of central third weight-bearing region and superficial zones ART. Both cohorts showed increased ART in superficial zone. Four impact athletes showed macroscopic changes. CLINICAL RELEVANCE This study demonstrates a quantitative MRI sequence able to detect signal differences in articular cartilage in asymptomatic athletes.
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26
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T1
ρ
mapping for the evaluation of high intensity focused ultrasound tumor treatment. Magn Reson Med 2014; 73:1593-601. [DOI: 10.1002/mrm.25269] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 03/18/2014] [Accepted: 04/07/2014] [Indexed: 12/22/2022]
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27
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Li Y, Zhao F, Wang YX, Ahuja AT, Yuan J. Study of magnetization evolution by using composite spin-lock pulses for T₁ρ imaging. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:408-11. [PMID: 23365915 DOI: 10.1109/embc.2012.6345954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
B(0) and B(1) field inhomogeneities may generate banding-like artifacts in T(1ρ)-weighted images and hence result in errors of T(1ρ) quantification. Several types of composite spin-lock pulses have been proposed to alleviate such artifacts. In this study, magnetization evolution with T(1ρ) and T(2ρ) relaxation by using these composite spin-lock pulses are theoretically derived. The effectiveness and limitation of each spin-lock pulse are explicitly illustrated in mathematical forms and phantom T(1ρ)-weighted images acquired by using each spin-lock pulse are presented. This study also provides a theoretical framework for T(1ρ) quantification from T(1ρ)-weighted images even with B(0) and B(1) inhomogeneity artifacts.
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Affiliation(s)
- Yujia Li
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
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28
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Cobb JG, Kan JH, Gore JC. T1ρ mapping of pediatric epiphyseal and articular cartilage in the knee. J Magn Reson Imaging 2013; 38:299-305. [PMID: 23650103 DOI: 10.1002/jmri.23963] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 10/18/2012] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To evaluate the feasibility of measuring T1ρ values in epiphyseal cartilage in children, we have conducted a novel study of spin locking techniques. Adult articular cartilage has been widely studied with spin locking techniques by magnetic resonance imaging. However, no results are available for in vivo T1ρ imaging of developing cartilage. MATERIALS AND METHODS Ten volunteers of age 6 ± 3 years were recruited to have T1ρ mapping performed on the knee at the conclusion of their clinical study. T1ρ maps were generated using a spin-lock cluster followed by a fast spin-echo imaging sequence. Regions of interest (ROIs) were placed in non-load-bearing (NLB), load-bearing (LB), and articular cartilage. RESULTS Student's t-tests were performed to compare means among the ROIs. Mean T1ρ for epiphyseal and articular cartilage was 49.8 ± 9 and 76.6 ± 7 ms, respectively. LB and NLB T1ρ vales were 47.1 ± 9.5 and 52.5 ± 9 ms, respectively. Significant differences were found in T1ρ values between epiphyseal and articular cartilage layers (P = 0.0001). No difference in T1ρ was observed between NLB and LB layers. A modest trend was also noted for epiphyseal and articular cartilage regions with age. CONCLUSION It is feasible to quantify differences in epiphyseal and articular cartilage layers with SL techniques. T1ρ holds promise as a noninvasive method of studying normal and abnormal developmental states of cartilage in children.
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Affiliation(s)
- Jared Guthrie Cobb
- Vanderbilt University Department of Biomedical Engineering, Nashville, Tennessee, USA.
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29
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Zhou Z, Jiang B, Zhou Z, Pan X, Sun H, Huang B, Liang T, Ringgaard S, Zou X. Intervertebral disk degeneration: T1ρ MR imaging of human and animal models. Radiology 2013; 268:492-500. [PMID: 23579049 DOI: 10.1148/radiol.13120874] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate disk degeneration in human and animal models by using a T1ρ magnetic resonance (MR) imaging technique to help in understanding the natural history and progression of intervertebral disk degeneration. MATERIALS AND METHODS After institutional review board approval was obtained, 80 subjects (54 men and 26 women; mean age ± standard deviation, 31.6 years ± 6.20) with 400 lumbar intervertebral disks were examined at MR imaging. With approval from the animal care committee, six rhesus monkeys received two levels of either annulus fibrosus puncture or pingyangmycin subendplate injection at L3-4 and L5-6 to mimic disk degeneration. Lumbar spines of all the animals were examined at radiography and MR imaging preoperatively and 1 day and 1, 3, 6, 9, and 13 months postoperatively. Pfirrmann grading system and T1ρ quantification were used to evaluate the degenerative degree of the disks of both humans and animals. RESULTS The mean T1ρ values of lumbar intervertebral disks of human subjects were 136.0 msec ± 31.4 and 76.1 msec ± 14.2 at Pfirrmann grades II and III, respectively. The T1ρ values in lumbar intervertebral disks of the rhesus monkey models of disk degeneration had a rapid decrease from approximately 110 msec to 80 msec and then tended to stabilize after operation. There was a large T1ρ value decrease between Pfirrmann grades II and III in human subjects that coincided with the rapid degeneration process of lumbar intervertebral disks in the rhesus monkeys. Pfirrmann grades were significantly correlated with T1ρ values in both humans (r = -0.681, P < .001) and rhesus monkeys (r = -0.824, P < .001). CONCLUSION The data demonstrate that rapid intervertebral disk degeneration occurs early in the degenerative cascade, between Pfirrmann grades II and III.
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Affiliation(s)
- Zhiyu Zhou
- Department of Spinal Surgery, Orthopaedic Research Institute, the First Affiliated Hospital of Sun Yat-sen University, 510080 Guangzhou, People's Republic of China
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Murase K. Behavior of the magnetization in spin-locking magnetic resonance imaging using numerical solutions to the time-dependent Bloch equations. Phys Med Biol 2012; 57:N481-92. [DOI: 10.1088/0031-9155/57/23/n481] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Yuan J, Li Y, Zhao F, Chan Q, Ahuja AT, Wang YXJ. Quantification of T(1ρ) relaxation by using rotary echo spin-lock pulses in the presence of B(0) inhomogeneity. Phys Med Biol 2012; 57:5003-16. [PMID: 22805278 DOI: 10.1088/0031-9155/57/15/5003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
T(1ρ) relaxation is traditionally described as a mono-exponential signal decay with spin-lock time. However, T(1ρ) quantification by fitting to the mono-exponential model can be substantially compromised in the presence of field inhomogeneities, especially for low spin-lock frequencies. The normal approach to address this issue involves the development of dedicated composite spin-lock pulses for artifact reduction while still using the mono-exponential model for T(1ρ) fitting. In this work, we propose an alternative approach for improved T(1ρ) quantification with the widely-used rotary echo spin-lock pulses in the presence of B(0) inhomogeneities by fitting to a modified theoretical model which is derived to reveal the dependence of T(1ρ)-prepared magnetization on T(1ρ), T(2ρ), spin-lock time, spin-lock frequency and off-resonance, without involving complicated spin-lock pulse design. It has potentials for T(1ρ) quantification improvement at low spin-lock frequencies. Improved T(1ρ) mapping was demonstrated on phantom and in vivo rat spin-lock imaging at 3 T compared to the mapping using the mono-exponential model.
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Affiliation(s)
- Jing Yuan
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People’s Republic of China.
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Zhao F, Deng M, Yuan J, Teng GJ, Ahuja AT, Wang YXJ. Experimental evaluation of accelerated T1rho relaxation quantification in human liver using limited spin-lock times. Korean J Radiol 2012; 13:736-42. [PMID: 23118572 PMCID: PMC3484294 DOI: 10.3348/kjr.2012.13.6.736] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 05/15/2012] [Indexed: 12/17/2022] Open
Abstract
Objective It was reported lately that to obtain consistent liver T1rho measurement, at 3T MRI using six spin-lock times (SLTs), is feasible. In this study, the feasibility of using three or two SLT points to measure liver T1rho relaxation time was explored. Materials and Methods Seventeen healthy volunteers underwent 36 examinations. Three representative axial slices were selected to cut through the upper, middle, and lower liver. A rotary echo spin-lock pulse was implemented in a 2D fast field echo sequence. Spin-lock frequency was 500 Hz and the spin-lock times of 1, 10, 20, 30, 40, and 50 milliseconds (ms) were used for T1rho mapping. T1rho maps were constructed by using all 6 SLT points, three SLT points of 1, 20, and 50 ms, or two SLTs of 1 and 50 ms, respectively. Intra-class correlation coefficient (ICC) and Bland and Altman plot were used to assess the measurement agreement. Results Two examinations were excluded, due to motion artifact at the SLT of 50 ms. With the remaining 34 examinations, the ICC for 6-SLT vs. 3-SLT T1rho measurements was 0.922, while the ICC for 6-SLT vs. 2-SLT T1rho measurement was 0.756. The Bland and Altman analysis showed a mean difference of 0.19 (95% limits of agreement: -1.34, 1.73) for 6-SLT vs. 3-SLT T1rho measurement, and the mean difference of 0.89 (95% limits of agreement: -1.67, 3.45) for 6-SLT vs. 2-SLT T1rho measurement. The scan re-scan reproducibility ICC (n = 11 subjects) was 0.755, 0.727, and 0.528 for 6-SLT measurement, 3-SLT measurement, and 2-SLT measurement, respectively. Conclusion Adopting 3 SLTs of 1, 20, and 50 ms can be an acceptable alternative for the liver T1rho measurement, while 2 SLTs of 1 and 50 ms do not provide reliable measurement.
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Affiliation(s)
- Feng Zhao
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China
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Yuan J, Zhao F, Chan Q, Wang YXJ. Observation of bi-exponential T(1ρ) relaxation of in-vivo rat muscles at 3T. Acta Radiol 2012; 53:675-81. [PMID: 22761346 DOI: 10.1258/ar.2012.120108] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Spin-lattice relaxation in the rotating frame, or T(1ρ) relaxation, is normally described by a mono-exponential decay model. However, compartmentation of tissues and microscopic molecular exchange may lead to bi-exponential or multi-exponential T(1ρ) relaxation behavior in certain tissues under the application of spin lock pulse field strength. PURPOSE To investigate the presence of bi-exponential T(1ρ) relaxations in in-vivo rat head tissues of brain and muscle. MATERIAL AND METHODS Five Sprague-Dawley rats underwent T(1ρ) imaging at 3T. A B(1)-insensitive rotary echo spin lock pulse was used for T(1ρ) preparation with a spin lock frequency of 500Hz. Twenty-five T(1ρ)-weighted images with spin lock times ranging from 1 to 60 ms were acquired using a 3D spoiled gradient echo sequence. Image intensities over different spin lock times were fitted using mono-exponential as well as bi-exponential models both on region-of-interest basis and pixel-by-pixel basis. F-test with a significance level P value of 0.01 was used to evaluate whether bi-exponential model gave a better fitting than mono-exponential model. RESULTS In rat brains, only mono-exponential but no apparent bi-exponential T(1ρ) relaxation (~70-71 ms) was found. In contrast, bi-exponential T(1ρ) relaxation was observed in muscles of all five rats (P < 10(-4)). A longer and a shorter T(1ρ) relaxation component were extracted to be ~37- ~41 ms (a fraction of ~80- ~88%) and ~9- ~11 ms (~12-20%), compared to the normal single T(1ρ) relaxation of ~30- ~33 ms. CONCLUSION Bi-exponential relaxation components were detected in rat muscles. The long and the short T(1ρ) relaxation component are thought to correspond to the restricted intracellular water population and the hydrogen exchange between amine and hydroxyl groups, respectively.
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Affiliation(s)
- Jing Yuan
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Feng Zhao
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Queenie Chan
- Philips Healthcare, Philips Electronics Hong Kong Limited, Hong Kong, China
| | - Yi-Xiang J Wang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
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Abstract
Osteoarthritis (OA) is a common disease that results in cartilage degeneration in the joints and is a disabling condition for millions of individuals. Poor sensitivity and specificity of standard diagnostic methods have relegated treatment options to mitigating pain or surgical replacement. The advent of disease-modifying drugs holds the potential for reversing the normal course of OA and rebuilding cartilage. To aid these therapies, novel magnetic resonance imaging-based tools are required for detecting subtle early changes in cartilage physiology due to OA that may provide improved diagnoses and clinical management of patients. Some of the techniques reviewed here such as T1ρ and T2 relaxometry, magnetization transfer, chemical exchange saturation transfer, and Na magnetic resonance imaging are all biomarkers of cartilage pathological diseases that are sensitive to early biochemical changes in the extracellular matrix of cartilage. These techniques have the potential to noninvasively detect early pathological changes with the goal of aiding clinical decision making as well as contributing to the development and evaluation of potential disease-modifying therapies.
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MR T1ρ as an imaging biomarker for monitoring liver injury progression and regression: an experimental study in rats with carbon tetrachloride intoxication. Eur Radiol 2012; 22:1709-16. [PMID: 22752522 DOI: 10.1007/s00330-012-2419-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 12/04/2011] [Accepted: 01/03/2012] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Recently it was shown that the magnetic resonance imaging (MRI) T1ρ value increased with the severity of liver fibrosis in rats with bile duct ligation. Using a rat carbon tetrachloride (CCl(4)) liver injury model, this study further investigated the merit of T1ρ relaxation for liver fibrosis evaluation. METHODS Male Sprague-Dawley rats received intraperitoneal injection of 2 ml/kg CCl(4) twice weekly for up to 6 weeks. Then CCl(4) was withdrawn and the animals were allowed to recover. Liver T1ρ MRI and conventional T2-weighted images were acquired. Animals underwent MRI at baseline and at 2 days, 2 weeks, 4 weeks and 6 weeks post CCl(4) injection, and they were also examined at 1 week and 4 weeks post CCl(4) withdrawal. Liver histology was also sampled at these time points. RESULTS Liver T1ρ values increased slightly, though significantly, on day 2, and then increased further and were highest at week 6 post CCl(4) insults. The relative liver signal intensity change on T2-weighted images followed a different time course compared with that of T1ρ. Liver T1ρ values decreased upon the withdrawal of the CCl(4) insult. Histology confirmed the animals had typical CCl(4) liver injury and fibrosis progression and regression processes. CONCLUSIONS MR T1ρ imaging can monitor CCl(4)-induced liver injury and fibrosis. KEY POINTS • MR T1ρ is a valuable imaging biomarker for liver injury/fibrosis. • Liver T1ρ was only mildly affected by oedema and acute inflammation. • Liver MR T1ρ decreased when liver fibrosis and injury regressed.
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Richardson OC, Scott MLJ, Tanner SF, Waterton JC, Buckley DL. Overcoming the low relaxivity of gadofosveset at high field with spin locking. Magn Reson Med 2011; 68:1234-8. [PMID: 22161901 PMCID: PMC3666098 DOI: 10.1002/mrm.23316] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 11/10/2011] [Accepted: 11/12/2011] [Indexed: 01/13/2023]
Abstract
The contrast agent gadofosveset, which binds reversibly to serum albumin, has a high longitudinal relaxivity at lower magnetic fields (≤3.0 T) but a much lower relaxivity at high fields. Spin locking is sensitive to macromolecular content; it is hypothesized that combining this technique with the albumin-binding properties of gadofosveset may enable increased relaxivity at high fields. In vitro measurements at 4.7 T found significantly higher spin-lock relaxation rates, R1ρ (1/T1ρ), when gadofosveset was serum albumin-bound than when unbound. R1ρ values for a nonbinding contrast agent (gadopentetate dimeglumine) in serum albumin were similar to those for unbound gadofosveset. R2 (1/T2) values were also significantly higher at 4.7 T for serum albumin-bound gadofosveset than for unbound. Spin locking at high field generates significantly higher relaxation rates for gadofosveset than conventional contrast agents and may provide a method for differentiating free and bound molecules at these field strengths.
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Affiliation(s)
- O C Richardson
- Division of Medical Physics, University of Leeds, Leeds, UK
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Fenty MC, Dodge GR, Kassey VB, Witschey WRT, Borthakur A, Reddy R. Quantitative cartilage degeneration associated with spontaneous osteoarthritis in a guinea pig model. J Magn Reson Imaging 2011; 35:891-8. [PMID: 22128105 DOI: 10.1002/jmri.22867] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 09/30/2011] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To determine (i) the feasibility and intra- and inter-scan reproducibility of T(1ρ) MRI in assessing cartilage degeneration in a guinea pig model with naturally occurring joint disease that closely mimics human osteoarthritis (OA), (ii) demonstrate the sensitivity of T(1ρ) MRI in assessing the age dependent cartilage degeneration in OA progression as compared to histopathological changes. MATERIALS AND METHODS Duncan-Hartley guinea pigs were obtained at various ages and maintained under an IACUC approved protocol. The left hind stifle joint was imaged using T(1ρ) MRI on a 9.4 Tesla Varian horizontal 20 cm bore scanner using a custom surface coil. Reproducibility of T(1ρ) MRI was assessed using 4-month-old guinea pigs (N = 3). Three age cohorts; 3 month (N = 8), 5 month (N = 6), and 9 month (N = 5), were used to determine the age-dependent osteoarthritic changes as measured by T(1ρ) MRI. Validation of age-dependent cartilage degeneration was confirmed by histology and Safranin-O staining. RESULTS T(1ρ) values obtained in the cartilage of the stifle joint in guinea pigs were highly reproducible with an inter-scan mean coefficient of variation (CV) of 6.57% and a maximum intra-scan CV of 9.29%. Mean cartilage T(1ρ) values in animals with late stage cartilage degeneration were 56.3-56.9 ms (5-9 month cohorts) were both significantly (P < 0.01) higher than that obtained from 3-month-old cohort (44 ms) demonstrating an age-dependent variation. T(1ρ) was shown to be significantly greater than T(2) . T(1ρ) dispersion was observed in this animal model for the first time showing an increase of 45% between 500 Hz and 1500 Hz spin-locking frequency. Cartilage thickness measurements were calculated from single mid-coronal histology sections from same animals used for T(1ρ) MRI. Thickness calculations showed insignificant differences between 3- and 5-month cohorts and was significantly decreased by 9 months of age (P < 0.01). A moderate correlation (R(2) = 0.45) existed between T(1ρ) values and signal intensity of Safranin-O stain. CONCLUSION The data presented demonstrate that T(1ρ) MRI is highly reproducible in this spontaneous model of OA and may serve as a noninvasive tool to characterize joint cartilage degeneration during OA. Age-dependent changes, verified with histological measurements of proteoglycan loss, correlated with T(1ρ) across different age groups. T(1ρ) has adequate dynamic range and is sensitive to detect and track the progression of cartilage degeneration in the guinea pig model before gross anatomical changes such as cartilage thinning has occurred. This study presents a technological advancement that would permit longitudinal studies of evaluating disease-modifying therapies useful for treating human OA.
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Affiliation(s)
- Matthew C Fenty
- CMROI, Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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Sirlin CB. Science to practice: Can T1rho imaging be used to diagnose and assess the severity of hepatic fibrosis? Radiology 2011; 259:619-20. [PMID: 21602499 DOI: 10.1148/radiol.11110547] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Claude B Sirlin
- Liver Imaging Group, Department of Radiology, University of California, 408 Dickinson St, San Diego, CA 92103-8226, USA.
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Chen W, Takahashi A, Han E. Quantitative T(1)(ρ) imaging using phase cycling for B0 and B1 field inhomogeneity compensation. Magn Reson Imaging 2011; 29:608-19. [PMID: 21524869 DOI: 10.1016/j.mri.2011.02.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 02/26/2011] [Indexed: 10/18/2022]
Abstract
T(1)(ρ) imaging is useful in a number of clinical applications. T(1)(ρ) preparation methods, however, are sensitive to non-uniformities of the B0 magnetic field and the B1 RF field. These common system imperfections can result in image artifacts and quantification errors in T(1)(ρ) imaging. We report on a phase-cycling method which can eliminate B1 RF inhomogeneity effects in T(1)(ρ) imaging. This method does not only correct for image artifacts but also for T(2)(ρ) contamination caused by B1 RF inhomogeneity. The presence of B0 magnetic field inhomogeneity can compromise the effectiveness of this method for B1 RF inhomogeneity correction. We demonstrate that, by combining the spin-locking scheme reported by Dixon et al. (Myocardial suppression in vivo by spin locking with composite pulses. Magn Reson Med 1996; 36:90-94) with phase cycling, we can simultaneously correct B0 magnetic field inhomogeneity effects and B1 RF inhomogeneity effects in T(1)(ρ) imaging. Phantom and in vivo data sets are used to demonstrate the proposed methods and to compare them with other existing T(1)(ρ) preparation methods.
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Affiliation(s)
- Weitian Chen
- Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA 94025, USA.
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Wang YXJ, Yuan J, Chu ESH, Go MYY, Huang H, Ahuja AT, Sung JJY, Yu J. T1rho MR imaging is sensitive to evaluate liver fibrosis: an experimental study in a rat biliary duct ligation model. Radiology 2011; 259:712-9. [PMID: 21436087 DOI: 10.1148/radiol.11101638] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To correlate spin-lattice relaxation time in the rotating frame (T1ρ) measurements with degree of liver fibrosis in a rat model. MATERIALS AND METHODS The protocols and procedures were approved by the local Animal Experimentation Ethics Committee. Liver fibrosis was induced with biliary duct ligation (BDL). Two studies, 1 month apart, were performed with a 3-T clinical imager. The first study involved longitudinal magnetic resonance (MR) imaging follow-up of BDL rats (n = 8) and control rats (n = 4) on days 8, 15, 21, and 29 after BDL. The second study involved MR imaging of another group of BDL and control rats (n = 5 for each) on days 24 and 38 after BDL. Hematoxylin-eosin and picrosirius red staining were performed in liver specimens from days 8, 15, 24, and 38 after BDL. Repeated-measures analysis of variance was used, and treatment groups were compared (Bonferroni adjustment). RESULTS On day 8, there were proliferation of bile duct and inflammatory cell infiltration around portal triads. While there was overlap, BDL rats (n = 8) demonstrated higher mean liver T1ρ values than did control rats (n = 4) on day 8 (46.7 msec ± 2.9 [standard deviation] vs 44.7 msec ± 1.2, P = .4). On day 15, BDL rats demonstrated liver fibrosis with a background of inflammatory infiltration. On day 15, mean T1ρ values in BDL rats could be largely separated from those in control rats (52.6 msec ± 6.0 vs 43.8 msec ± 1.5, P = .02). On day 24, BDL rats had liver T1ρ values 23.5% higher than in control rats (n = 5 for each group, P = .0007). Histomorphometric analysis showed that collagen content increased after surgery from days 8 to 24 (n = 6 for each group, P < .0001), with no further increase between days 24 and 38 (n = 6 for each group, P >.99). CONCLUSION In this model, liver fibrosis was detected with T1ρ MR imaging; the degree of fibrosis was correlated with degree of increase in T1ρ measurements. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101638/-/DC1.
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Affiliation(s)
- Yi-Xiang J Wang
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, the Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
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Jin T, Autio J, Obata T, Kim SG. Spin-locking versus chemical exchange saturation transfer MRI for investigating chemical exchange process between water and labile metabolite protons. Magn Reson Med 2010; 65:1448-60. [PMID: 21500270 DOI: 10.1002/mrm.22721] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 10/13/2010] [Accepted: 10/17/2010] [Indexed: 11/09/2022]
Abstract
Chemical exchange saturation transfer (CEST) and spin-locking (SL) experiments were both able to probe the exchange process between protons of nonequivalent chemical environments. To compare the characteristics of the CEST and SL approaches in the study of chemical exchange effects, we performed CEST and SL experiments at varied pH and concentrated metabolite phantoms with exchangeable amide, amine, and hydroxyl protons at 9.4 T. Our results show that: (i) on-resonance SL is most sensitive to chemical exchanges in the intermediate-exchange regime and is able to detect hydroxyl and amine protons on a millimolar concentration scale. Off-resonance SL and CEST approaches are sensitive to slow-exchanging protons when an optimal SL or saturation pulse power matches the exchanging rate, respectively. (ii) Offset frequency-dependent SL and CEST spectra are very similar and can be explained well with an SL model recently developed by Trott and Palmer (J Magn Reson 2002;154:157-160). (iii) The exchange rate and population of metabolite protons can be determined from offset-dependent SL or CEST spectra or from on-resonance SL relaxation dispersion measurements. (iv) The asymmetry of the magnetization transfer ratio (MTR(asym)) is highly dependent on the choice of saturation pulse power. In the intermediate-exchange regime, MTR(asym) becomes complicated and should be interpreted with care.
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Affiliation(s)
- Tao Jin
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15203, USA.
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Witschey WRT, Borthakur A, Elliott MA, Fenty M, Sochor MA, Wang C, Reddy R. T1rho-prepared balanced gradient echo for rapid 3D T1rho MRI. J Magn Reson Imaging 2008; 28:744-54. [PMID: 18777535 DOI: 10.1002/jmri.21444] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To develop a T1rho-prepared, balanced gradient echo (b-GRE) pulse sequence for rapid three-dimensional (3D) T1rho relaxation mapping within the time constraints of a clinical exam (<10 minutes), examine the effect of acquisition on the measured T1rho relaxation time and optimize 3D T1rho pulse sequences for the knee joint and spine. MATERIALS AND METHODS A pulse sequence consisting of inversion recovery-prepared, fat saturation, T1rho-preparation, and b-GRE image acquisition was used to obtain 3D volume coverage of the patellofemoral and tibiofemoral cartilage and lower lumbar spine. Multiple T1rho-weighted images at various contrast times (spin-lock pulse duration [TSL]) were used to construct a T1rho relaxation map in both phantoms and in the knee joint and spine in vivo. The transient signal decay during b-GRE image acquisition was corrected using a k-space filter. The T1rho-prepared b-GRE sequence was compared to a standard T1rho-prepared spin echo (SE) sequence and pulse sequence parameters were optimized numerically using the Bloch equations. RESULTS The b-GRE transient signal decay was found to depend on the initial T1rho-preparation and the corresponding T1rho map was altered by variations in the point spread function with TSL. In a two compartment phantom, the steady state response was found to elevate T1rho from 91.4+/-6.5 to 293.8+/-31 and 66.9+/-3.5 to 661+/-207 with no change in the goodness-of-fit parameter R2. Phase encoding along the longest cartilage dimension and a transient signal decay k-space filter retained T1rho contrast. Measurement of T1rho using the T1rho-prepared b-GRE sequence matches standard T1rho-prepared SE in the medial patellar and lateral patellar cartilage compartments. T1rho-preparedb-GRE T1rho was found to have low interscan variability between four separate scans. Mean patellar cartilage T1rho was elevated compared to femoral and tibial cartilage T1rho. CONCLUSION The T1rho-prepared b-GRE acquisition rapidly and reliably accelerates T1rho quantification of tissues offset partially by a TSL-dependent point spread function.
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Affiliation(s)
- Walter R T Witschey
- Metabolic Magnetic Resonance Research and Computing Center, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, USA.
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Regatte RR, Schweitzer ME. Novel contrast mechanisms at 3 Tesla and 7 Tesla. Semin Musculoskelet Radiol 2008; 12:266-80. [PMID: 18850506 DOI: 10.1055/s-0028-1083109] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Osteoarthritis (OA) is the most common musculoskeletal degenerative disease, affecting millions of people. Although OA has been considered primarily a cartilage disorder associated with focal cartilage degeneration, it is accompanied by well-known changes in subchondral and trabecular bone, including sclerosis and osteophyte formation. The exact cause of OA initiation and progression remains under debate, but OA typically first affects weightbearing joints such as the knee. Magnetic resonance imaging (MRI) has been recognized as a potential tool for quantitative assessment of cartilage abnormalities due to its excellent soft tissue contrast. Over the last two decades, several new MR biochemical imaging methods have been developed to characterize the disease process and possibly predict the progression of knee OA. These new MR biochemical methods play an important role not only for diagnosis of disease at an early stage, but also for their potential use in monitoring outcome of various drug therapies (success or failure). Recent advances in multicoil radiofrequency technology and high field systems (3 T and above) significantly improve the sensitivity and specificity of imaging studies for the diagnosis of musculoskeletal disorders. The current state-of-the-art MR imaging methods are briefly reviewed for the quantitative biochemical and functional imaging assessment of musculoskeletal systems.
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Affiliation(s)
- Ravinder R Regatte
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York 10003, USA.
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Martirosian P, Rommel E, Schick F, Deimling M. Control of susceptibility-related image contrast by spin-lock techniques. Magn Reson Imaging 2008; 26:1381-7. [PMID: 18586432 DOI: 10.1016/j.mri.2008.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 04/22/2008] [Accepted: 04/26/2008] [Indexed: 11/24/2022]
Abstract
Macroscopic magnetic field inhomogeneities might lead to image distortions, while microscopic field inhomogeneities, due to susceptibility changes in tissues, cause spin dephasing and decreasing T(2)() relaxation time. The latter effects are especially observed in the trabecular bone and in regions adjacent to air-containing cavities when gradient-echo sequences are applied. In conventional MRI, these susceptibility-related signal voids can be avoided by applying spin-echo (SE) techniques. In this study, an alternative method for the examination and control of susceptibility-related effects by spin-lock (SL) radiofrequency pulses is presented: SL pulses were applied in two different susceptibility-sensitive sequence types: (a) between the jump and return 90 degrees pulses in a 90 degrees (x)-tau-90 degrees (-x) magnetization-prepared Fast Low Angle Shot (FLASH) sequence and (b) between the 90 degrees pulse and the 180 degrees pulse in an asymmetric SE sequence. The range of Larmor frequencies used for spin locking can be determined for different B(1) amplitudes of the SL pulses, allowing control of image contrast by the amplitude of the SL pulses.
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Affiliation(s)
- Petros Martirosian
- Section on Experimental Radiology, University of Tübingen, 72076 Tübingen, Germany.
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Wang C, Auerbach JD, Witschey WRT, Balderston RA, Reddy R, Borthakur A. Advances in Magnetic Resonance Imaging for the assessment of degenerative disc disease of the lumbar spine. ACTA ACUST UNITED AC 2007; 19:65-71. [PMID: 18037984 DOI: 10.1053/j.semss.2007.04.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The intervertebral disc is characterized by a tension-resisting annulus fibrosus, and a compression-resisting nucleus pulposus composed largely of proteoglycan. Both the annulus and the nucleus function in concert to provide the disc with mechanical stability. Early disc degeneration begins in the nucleus with proteoglycan depletion. Quantitative MRI techniques have been developed to non-invasively quantify the earliest degenerative changes that occur within the disc. Our ability to identify and quantify these early biochemical changes will provide a better understanding of the pathophysiology of disc degeneration and facilitate the study of interventions that aim to halt or reverse the degenerative process.
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Affiliation(s)
- Chenyang Wang
- Graduate Student, Department of Bioengineering University of Pennsylvania, Philadelphia, PA 19104
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Zhang H, Xie Y, Ji T. Water diffusion-exchange effect on the paramagnetic relaxation enhancement in off-resonance rotating frame. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 186:259-72. [PMID: 17412624 PMCID: PMC2041893 DOI: 10.1016/j.jmr.2007.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Revised: 03/11/2007] [Accepted: 03/12/2007] [Indexed: 05/14/2023]
Abstract
The off-resonance rotating frame technique based on the spin relaxation properties of off-resonance T1rho can significantly increase the sensitivity of detecting paramagnetic labeling at high magnetic fields by MRI. However, the in vivo detectable dimension for labeled cell clusters/tissues in T1rho-weighted images is limited by the water diffusion-exchange between mesoscopic scale compartments. An experimental investigation of the effect of water diffusion-exchange between compartments on the paramagnetic relaxation enhancement of paramagnetic agent compartment is presented for in vitro/in vivo models. In these models, the size of paramagnetic agent compartment is comparable to the mean diffusion displacement of water molecules during the long RF pulses that are used to generate the off-resonance rotating frame. The three main objectives of this study were: (1) to qualitatively correlate the effect of water diffusion-exchange with the RF parameters of the long pulse and the rates of water diffusion, (2) to explore the effect of water diffusion-exchange on the paramagnetic relaxation enhancement in vitro, and (3) to demonstrate the paramagnetic relaxation enhancement in vivo. The in vitro models include the water permeable dialysis tubes or water permeable hollow fibers embedded in cross-linked proteins gels. The MWCO of the dialysis tubes was chosen from 0.1 to 15 kDa to control the water diffusion rate. Thin hollow fibers were chosen to provide sub-millimeter scale compartments for the paramagnetic agents. The in vivo model utilized the rat cerebral vasculatures as a paramagnetic agent compartment, and intravascular agents (Gd-DTPA)30-BSA were administrated into the compartment via bolus injections. Both in vitro and in vivo results demonstrate that the paramagnetic relaxation enhancement is predominant in the T1rho-weighted image in the presence of water diffusion-exchange. The T1rho contrast has substantially higher sensitivity than the conventional T1 contrast in detecting paramagnetic agents, especially at low paramagnetic agent volumetric fractions, low paramagnetic agent concentrations, and low RF amplitudes. Short pulse duration, short pulse recycle delay and efficient paramagnetic relaxation can reduce the influence of water diffusion-exchange on the paramagnetic enhancement. This study paves the way for the design of off-resonance rotating experiments to detect labeled cell clusters/tissue compartments in vivo at a sub-millimeter scale.
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Affiliation(s)
- Huiming Zhang
- Center for Basic MR Research, Evanston Northwestern Healthcare Research Institute, Evanston, IL 60201, USA.
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Kettunen MI, Sierra A, Närväinen MJ, Valonen PK, Ylä-Herttuala S, Kauppinen RA, Gröhn OHJ. Low Spin-Lock Field T1 Relaxation in the Rotating Frame as a Sensitive MR Imaging Marker for Gene Therapy Treatment Response in Rat Glioma1. Radiology 2007; 243:796-803. [PMID: 17517934 DOI: 10.1148/radiol.2433052077] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively assess the effectiveness of T1 relaxation in the rotating frame (T1 rho) dispersion and the low spin-lock radiofrequency field (B(1)) T1 rho magnetic resonance (MR) imaging relaxation time in noninvasive monitoring of gene therapy response in BT4C glioma in rats. MATERIALS AND METHODS All animal studies were approved by the ethical committee of the National Laboratory Animal Center. Rats with BT4C gliomas (n=9) were treated with herpes simplex virus thymidine kinase gene therapy and were compared with untreated rats (n=5). Absolute T1 rho at a B(1) range of 2.0 x 10(-6) to 1.4 x 10(-4) T, T1, T2, and apparent diffusion constant were measured at 4.7 T during treatment. Statistical significance was tested by using repeated-measures analysis of variance. RESULTS A significant (P<.05) lengthening of T1 rho was observed beginning on the 4th day of treatment, and T1 rho values increased to be approximately 80% higher than values observed before treatment. These changes preceded T1 and T2 changes and resembled those of water diffusion. The T1 rho was associated with a treatment-induced decrease in cell density; this was the only measured MR imaging property that provided significant (P<.05) Pearson correlation with cell density in the tumor border. T1 rho relaxation dispersion, however, did not offer additional benefits over those offered in one B(1) experiment in the early phase of treatment. CONCLUSION T1 rho with low B(1) is an excellent MR imaging marker of early gene therapy response in gliomas. The low B(1) approach is not limited by specific absorption rate restrictions; this finding suggests that spin-lock methods could be applicable in clinical settings. (
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Affiliation(s)
- Mikko I Kettunen
- Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland.
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Witschey WRT, Borthakur A, Elliott MA, Mellon E, Niyogi S, Wallman DJ, Wang C, Reddy R. Artifacts in T1 rho-weighted imaging: compensation for B(1) and B(0) field imperfections. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 186:75-85. [PMID: 17291799 PMCID: PMC1995435 DOI: 10.1016/j.jmr.2007.01.015] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 01/23/2007] [Accepted: 01/23/2007] [Indexed: 05/13/2023]
Abstract
The origin of spin locking image artifacts in the presence of B(0) and B(1) magnetic field imperfections is shown theoretically using the Bloch equations and experimentally at low (omega(1) << Delta omega(0)), intermediate (omega(1) approximately Delta omega(0)) and high (omega(1) >> Delta omega(0)) spin locking field strengths. At low spin locking fields, the magnetization is shown to oscillate about an effective field in the rotating frame causing signature banding artifacts in the image. At high spin lock fields, the effect of the resonance offset Deltao mega(0) is quenched, but imperfections in the flip angle cause oscillations about the omega(1) field. A new pulse sequence is presented that consists of an integrated spin echo and spin lock experiment followed by magnetization storage along the -z-axis. It is shown that this sequence almost entirely eliminates banding artifacts from both types of field inhomogeneities at all spin locking field strengths. The sequence was used to obtain artifact free images of agarose in inhomogeneous B(0) and B(1) fields, off-resonance spins in fat and in vivo human brain images at 3 T. The new pulse sequence can be used to probe very low frequency (0-400 Hz) dynamic and static interactions in tissues without contaminating B(0) and B(1) field artifacts.
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Affiliation(s)
- Walter R T Witschey
- Graduate Group in Biochemistry and Molecular Biophysics and MMRRCC, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA 19104-6100, USA.
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Witschey WRT, Borthakur A, Elliott MA, Mellon E, Niyogi S, Wang C, Reddy R. Compensation for spin-lock artifacts using an off-resonance rotary echo in T1rhooff-weighted imaging. Magn Reson Med 2007; 57:2-7. [PMID: 17191245 PMCID: PMC2877388 DOI: 10.1002/mrm.21134] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The origin of image artifacts in an off-resonance spin-locking experiment is shown to be imperfections in the excitation flip angle. A pulse sequence for off-resonance spin locking is implemented that compensates for imperfections in the excitation flip angle through an off-resonance rotary echo. The off-resonance rotary echo alternates the frequency offset and phase of the RF transmitter during two spin-locking pulses of equal duration. The underlying theory is detailed, and MR images demonstrate the effectiveness of the technique in agarose gel phantoms and in in vivo human brain at 3T.
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Affiliation(s)
- Walter R T Witschey
- Department of Biochemistry & Molecular Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, USA.
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Borthakur A, Mellon E, Niyogi S, Witschey W, Kneeland JB, Reddy R. Sodium and T1rho MRI for molecular and diagnostic imaging of articular cartilage. NMR IN BIOMEDICINE 2006; 19:781-821. [PMID: 17075961 PMCID: PMC2896046 DOI: 10.1002/nbm.1102] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this article, both sodium magnetic resonance (MR) and T1rho relaxation mapping aimed at measuring molecular changes in cartilage for the diagnostic imaging of osteoarthritis are reviewed. First, an introduction to structure of cartilage, its degeneration in osteoarthritis (OA) and an outline of diagnostic imaging methods in quantifying molecular changes and early diagnostic aspects of cartilage degeneration are described. The sodium MRI section begins with a brief overview of the theory of sodium NMR of biological tissues and is followed by a section on multiple quantum filters that can be used to quantify both bi-exponential relaxation and residual quadrupolar interaction. Specifically, (i) the rationale behind the use of sodium MRI in quantifying proteoglycan (PG) changes, (ii) validation studies using biochemical assays, (iii) studies on human OA specimens, (iv) results on animal models and (v) clinical imaging protocols are reviewed. Results demonstrating the feasibility of quantifying PG in OA patients and comparison with that in healthy subjects are also presented. The section concludes with the discussion of advantages and potential issues with sodium MRI and the impact of new technological advancements (e.g. ultra-high field scanners and parallel imaging methods). In the theory section on T1rho, a brief description of (i) principles of measuring T1rho relaxation, (ii) pulse sequences for computing T1rho relaxation maps, (iii) issues regarding radio frequency power deposition, (iv) mechanisms that contribute to T1rho in biological tissues and (v) effects of exchange and dipolar interaction on T1rho dispersion are discussed. Correlation of T1rho relaxation rate with macromolecular content and biomechanical properties in cartilage specimens subjected to trypsin and cytokine-induced glycosaminoglycan depletion and validation against biochemical assay and histopathology are presented. Experimental T1rho data from osteoarthritic specimens, animal models, healthy human subjects and as well from osteoarthritic patients are provided. The current status of T1rho relaxation mapping of cartilage and future directions is also discussed.
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Affiliation(s)
- Arijitt Borthakur
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Eric Mellon
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Sampreet Niyogi
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Walter Witschey
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - J. Bruce Kneeland
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
| | - Ravinder Reddy
- MMRRCC, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
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