101
|
Oei EHG, van Tiel J, Robinson WH, Gold GE. Quantitative radiologic imaging techniques for articular cartilage composition: toward early diagnosis and development of disease-modifying therapeutics for osteoarthritis. Arthritis Care Res (Hoboken) 2014; 66:1129-41. [PMID: 24578345 DOI: 10.1002/acr.22316] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/18/2014] [Indexed: 12/19/2022]
Affiliation(s)
- Edwin H G Oei
- Stanford University, Stanford, California; Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | | | | | | |
Collapse
|
102
|
Nuclear overhauser enhancement mediated chemical exchange saturation transfer imaging at 7 Tesla in glioblastoma patients. PLoS One 2014; 9:e104181. [PMID: 25111650 PMCID: PMC4128651 DOI: 10.1371/journal.pone.0104181] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/10/2014] [Indexed: 11/19/2022] Open
Abstract
Background and Purpose Nuclear Overhauser Enhancement (NOE) mediated chemical exchange saturation transfer (CEST) is a novel magnetic resonance imaging (MRI) technique on the basis of saturation transfer between exchanging protons of tissue proteins and bulk water. The purpose of this study was to evaluate and compare the information provided by three dimensional NOE mediated CEST at 7 Tesla (7T) and standard MRI in glioblastoma patients. Patients and Methods Twelve patients with newly diagnosed histologically proven glioblastoma were enrolled in this prospective ethics committee–approved study. NOE mediated CEST contrast was acquired with a modified three-dimensional gradient-echo sequence and asymmetry analysis was conducted at 3.3ppm (B1 = 0.7 µT) to calculate the magnetization transfer ratio asymmetry (MTRasym). Contrast enhanced T1 (CE-T1) and T2-weighted images were acquired at 3T and used for data co-registration and comparison. Results Mean NOE mediated CEST signal based on MTRasym values over all patients was significantly increased (p<0.001) in CE-T1 tumor (−1.99±1.22%), tumor necrosis (−1.36±1.30%) and peritumoral CEST hyperintensities (PTCH) within T2 edema margins (−3.56±1.24%) compared to contralateral normal appearing white matter (−8.38±1.19%). In CE-T1 tumor (p = 0.015) and tumor necrosis (p<0.001) mean MTRasym values were significantly higher than in PTCH. Extent of the surrounding tumor hyperintensity was smaller in eight out of 12 patients on CEST than on T2-weighted images, while four displayed at equal size. In all patients, isolated high intensity regions (0.40±2.21%) displayed on CEST within the CE-T1 tumor that were not discernible on CE-T1 or T2-weighted images. Conclusion NOE mediated CEST Imaging at 7T provides additional information on the structure of peritumoral hyperintensities in glioblastoma and displays isolated high intensity regions within the CE-T1 tumor that cannot be acquired on CE-T1 or T2-weighted images. Further research is needed to determine the origin of NOE mediated CEST and possible clinical applications such as therapy assessment or biopsy planning.
Collapse
|
103
|
Wang P, Block J, Gore JC. Chemical exchange in knee cartilage assessed by R1ρ (1/T1ρ) dispersion at 3T. Magn Reson Imaging 2014; 33:38-42. [PMID: 25093631 DOI: 10.1016/j.mri.2014.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/25/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To quantify the characteristics of proton chemical exchange in knee cartilage in vivo by R1ρ dispersion analysis. MATERIALS AND METHODS Six healthy subjects (one female and five males, age range 24 to 71 y) underwent T1ρ imaging of knee cartilage on a 3T MRI scanner. Quantitative estimates of R1ρ (=1/T1ρ) were made using 5 different spin-lock durations for each of 12 different spin-lock amplitudes over the range 0 to 550Hz. When the variations of R1ρ with spin-locking strength (the R1ρ dispersion) are dominated by chemical exchange contributions, R1ρ dispersion curves can be analyzed to derive quantitative characteristics of the exchange and provide information on tissue composition. In this work, in vivo R1ρ dispersion of human knee articular cartilage at 3T was analyzed, and the exchange rates of protons between water and macromolecular hydroxyls (mainly in glycosaminoglycans) were estimated based on a theoretical model. RESULTS R1ρ values showed marked dispersion in articular cartilage and varied by approximately 50% between low and high values of the locking field, a change much greater than in surrounding tissues, consistent with greater contributions from chemical exchange. From the theoretical model, the exchange rates in cartilage were estimated to be in the range of 1.0-3.0kHz, and varied within the tissue. Variations within a single knee appear to be larger with increasing age. CONCLUSION R1ρ dispersion analysis may provide more specific information for studying cartilage biochemical composition and form the basis for quantitative evaluation of cartilage disorders.
Collapse
Affiliation(s)
- Ping Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Jake Block
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| |
Collapse
|
104
|
Sigurdsson U, Siversson C, Lammentausta E, Svensson J, Tiderius CJ, Dahlberg LE. In vivo transport of Gd-DTPA2- into human meniscus and cartilage assessed with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). BMC Musculoskelet Disord 2014; 15:226. [PMID: 25005036 PMCID: PMC4125346 DOI: 10.1186/1471-2474-15-226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 07/01/2014] [Indexed: 11/11/2022] Open
Abstract
Background Impaired stability is a risk factor in knee osteoarthritis (OA), where the whole joint and not only the joint cartilage is affected. The meniscus provides joint stability and is involved in the early pathological progress of OA. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been used to identify pre-radiographic changes in the cartilage in OA, but has been used less commonly to examine the meniscus, and then using only a double dose of the contrast agent. The purpose of this study was to enable improved early OA diagnosis by investigate the temporal contrast agent distribution in the meniscus and femoral cartilage simultaneously, in healthy volunteers, using 3D dGEMRIC at two different doses of the contrast agent Gd-DTPA2-. Methods The right knee in 12 asymptomatic volunteers was examined using a 3D Look-Locker sequence on two occasions after an intravenous injection of a double or triple dose of Gd-DTPA2- (0.2 or 0.3 mmol/kg body weight). The relaxation time (T1) and relaxation rate (R1 = 1/T1) were measured in the meniscus and femoral cartilage before, and 60, 90, 120 and 180 minutes after injection, and the change in relaxation rate (ΔR1) was calculated. Paired t-test and Analysis of Variance (ANOVA) were used for statistical evaluation. Results The triple dose yielded higher concentrations of Gd-DTPA2- in the meniscus and cartilage than the double dose, but provided no additional information. The observed patterns of ΔR1 were similar for double and triple doses of the contrast agent. ΔR1 was higher in the meniscus than in femoral cartilage in the corresponding compartments at all time points after injection. ΔR1 increased until 90-180 minutes in both the cartilage and the meniscus (p < 0.05), and was lower in the medial than in the lateral meniscus at all time points (p < 0.05). A faster increase in ΔR1 was observed in the vascularized peripheral region of the posterior medial meniscus, than in the avascular central part of the posterior medial meniscus during the first 60 minutes (p < 0.05). Conclusion It is feasible to examine undamaged meniscus and cartilage simultaneously using dGEMRIC, preferably 90 minutes after the injection of a double dose of Gd-DTPA2- (0.2 mmol/kg body weight).
Collapse
Affiliation(s)
- Ulf Sigurdsson
- Department of Orthopaedics, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden.
| | | | | | | | | | | |
Collapse
|
105
|
|
106
|
Cartilage repair surgery: outcome evaluation by using noninvasive cartilage biomarkers based on quantitative MRI techniques? BIOMED RESEARCH INTERNATIONAL 2014; 2014:840170. [PMID: 24877139 PMCID: PMC4024422 DOI: 10.1155/2014/840170] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/25/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND New quantitative magnetic resonance imaging (MRI) techniques are increasingly applied as outcome measures after cartilage repair. OBJECTIVE To review the current literature on the use of quantitative MRI biomarkers for evaluation of cartilage repair at the knee and ankle. METHODS Using PubMed literature research, studies on biochemical, quantitative MR imaging of cartilage repair were identified and reviewed. RESULTS Quantitative MR biomarkers detect early degeneration of articular cartilage, mainly represented by an increasing water content, collagen disruption, and proteoglycan loss. Recently, feasibility of biochemical MR imaging of cartilage repair tissue and surrounding cartilage was demonstrated. Ultrastructural properties of the tissue after different repair procedures resulted in differences in imaging characteristics. T2 mapping, T1rho mapping, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), and diffusion weighted imaging (DWI) are applicable on most clinical 1.5 T and 3 T MR scanners. Currently, a standard of reference is difficult to define and knowledge is limited concerning correlation of clinical and MR findings. The lack of histological correlations complicates the identification of the exact tissue composition. CONCLUSIONS A multimodal approach combining several quantitative MRI techniques in addition to morphological and clinical evaluation might be promising. Further investigations are required to demonstrate the potential for outcome evaluation after cartilage repair.
Collapse
|
107
|
Madelin G, Lee JS, Regatte RR, Jerschow A. Sodium MRI: methods and applications. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 79:14-47. [PMID: 24815363 PMCID: PMC4126172 DOI: 10.1016/j.pnmrs.2014.02.001] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 02/12/2014] [Indexed: 05/11/2023]
Abstract
Sodium NMR spectroscopy and MRI have become popular in recent years through the increased availability of high-field MRI scanners, advanced scanner hardware and improved methodology. Sodium MRI is being evaluated for stroke and tumor detection, for breast cancer studies, and for the assessment of osteoarthritis and muscle and kidney functions, to name just a few. In this article, we aim to present an up-to-date review of the theoretical background, the methodology, the challenges, limitations, and current and potential new applications of sodium MRI.
Collapse
Affiliation(s)
- Guillaume Madelin
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, New York, NY 10016, USA
| | - Jae-Seung Lee
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, New York, NY 10016, USA; Chemistry Department, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Ravinder R Regatte
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, New York, NY 10016, USA
| | - Alexej Jerschow
- Chemistry Department, New York University, 100 Washington Square East, New York, NY 10003, USA.
| |
Collapse
|
108
|
Chemical exchange saturation transfer MRI using intermolecular double-quantum coherences with multiple refocusing pulses. Magn Reson Imaging 2014; 32:759-65. [PMID: 24685983 DOI: 10.1016/j.mri.2014.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 02/16/2014] [Accepted: 03/07/2014] [Indexed: 01/27/2023]
Abstract
Chemical exchange saturation transfer (CEST) provides a new type of image contrast in MRI. Due to the intrinsically low CEST effect, new and improved experimental techniques are required to achieve reliable and quantitative CEST images. In the present work, we proposed a novel and more sensitive CEST acquisition approach, based on the intermolecular double-quantum coherence with a module of multiple refocusing pulses (iDQC-MRP). Experiments were performed on creatine and egg white phantoms using a Varian 7T animal MRI scanner. The iDQC-MRP CEST technique showed a substantial enhancement in CEST and nuclear Overhauser enhancement (NOE) signal intensities, compared to the standard single-quantum coherence approach. In addition, the iDQC-MRP approach increased the signal-to-noise ratio of acquired saturation images, compared to the conventional iDQC approach. The new iDQC-MRP CEST sequence provides a promising way for exploiting in vivo CEST and NOE imaging applications.
Collapse
|
109
|
He B, Wu JP, Kirk TB, Carrino JA, Xiang C, Xu J. High-resolution measurements of the multilayer ultra-structure of articular cartilage and their translational potential. Arthritis Res Ther 2014; 16:205. [PMID: 24946278 PMCID: PMC4061724 DOI: 10.1186/ar4506] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Current musculoskeletal imaging techniques usually target the macro-morphology of
articular cartilage or use histological analysis. These techniques are able to reveal
advanced osteoarthritic changes in articular cartilage but fail to give detailed
information to distinguish early osteoarthritis from healthy cartilage, and this
necessitates high-resolution imaging techniques measuring cells and the extracellular
matrix within the multilayer structure of articular cartilage. This review provides a
comprehensive exploration of the cellular components and extracellular matrix of
articular cartilage as well as high-resolution imaging techniques, including magnetic
resonance image, electron microscopy, confocal laser scanning microscopy, second
harmonic generation microscopy, and laser scanning confocal arthroscopy, in the
measurement of multilayer ultra-structures of articular cartilage. This review also
provides an overview for micro-structural analysis of the main components of normal
or osteoarthritic cartilage and discusses the potential and challenges associated
with developing non-invasive high-resolution imaging techniques for both research and
clinical diagnosis of early to late osteoarthritis.
Collapse
|
110
|
Zaiss M, Xu J, Goerke S, Khan IS, Singer RJ, Gore JC, Gochberg DF, Bachert P. Inverse Z-spectrum analysis for spillover-, MT-, and T1 -corrected steady-state pulsed CEST-MRI--application to pH-weighted MRI of acute stroke. NMR IN BIOMEDICINE 2014; 27:240-52. [PMID: 24395553 PMCID: PMC4520220 DOI: 10.1002/nbm.3054] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/08/2013] [Accepted: 10/30/2013] [Indexed: 05/03/2023]
Abstract
Endogenous chemical exchange saturation transfer (CEST) effects are always diluted by competing effects, such as direct water proton saturation (spillover) and semi-solid macromolecular magnetization transfer (MT). This leads to unwanted T2 and MT signal contributions that lessen the CEST signal specificity to the underlying biochemical exchange processes. A spillover correction is of special interest for clinical static field strengths and protons resonating near the water peak. This is the case for all endogenous CEST agents, such as amide proton transfer, -OH-CEST of glycosaminoglycans, glucose or myo-inositol, and amine exchange of creatine or glutamate. All CEST effects also appear to be scaled by the T1 relaxation time of water, as they are mediated by the water pool. This forms the motivation for simple metrics that correct the CEST signal. Based on eigenspace theory, we propose a novel magnetization transfer ratio (MTRRex ), employing the inverse Z-spectrum, which eliminates spillover and semi-solid MT effects. This metric can be simply related to Rex , the exchange-dependent relaxation rate in the rotating frame, and ka , the inherent exchange rate. Furthermore, it can be scaled by the duty cycle, allowing for simple translation to clinical protocols. For verification, the amine proton exchange of creatine in solutions with different agar concentrations was studied experimentally at a clinical field strength of 3 T, where spillover effects are large. We demonstrate that spillover can be properly corrected and that quantitative evaluation of pH and creatine concentration is possible. This proves that MTRRex is a quantitative and biophysically specific CEST-MRI metric. Applied to acute stroke induced in rat brain, the corrected CEST signal shows significantly higher contrast between the stroke area and normal tissue, as well as less B1 dependence, than conventional approaches.
Collapse
Affiliation(s)
- Moritz Zaiss
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ, German Cancer Research Center), Heidelberg, Germany
- Correspondence to: M. Zaiss, German Cancer Research Center (DKFZ), Department of Medical Physics in Radiology, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
| | - Junzhong Xu
- Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Steffen Goerke
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ, German Cancer Research Center), Heidelberg, Germany
| | - Imad S. Khan
- Section of Neurosurgery, Geisel School of Medicine at Dartmouth, Lebanon, NH
| | - Robert J. Singer
- Section of Neurosurgery, Geisel School of Medicine at Dartmouth, Lebanon, NH
| | - John C. Gore
- Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Daniel F. Gochberg
- Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
| | - Peter Bachert
- Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ, German Cancer Research Center), Heidelberg, Germany
| |
Collapse
|
111
|
|
112
|
Zbýň Š, Mlynárik V, Juras V, Szomolanyi P, Trattnig S. Sodium MR Imaging of Articular Cartilage Pathologies. CURRENT RADIOLOGY REPORTS 2014; 2:41. [PMID: 24683524 PMCID: PMC3963441 DOI: 10.1007/s40134-014-0041-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Many studies have proved that noninvasive sodium MR imaging can directly determine the cartilage GAG content, which plays a central role in cartilage homeostasis. New technical developments in the recent decade have helped to transfer this method from in vitro to pre-clinical in vivo studies. Sodium imaging has already been applied for the evaluation of cartilage and repair tissue in patients after various cartilage repair surgery techniques and in patients with osteoarthritis. These studies showed that this technique could be helpful not only for assessment of the cartilage status, but also predictive for osteoarthritis. However, due to the low detectable sodium MR signal in cartilage, sodium imaging is still challenging, and further hardware and software improvements are necessary for translating sodium MR imaging into clinical practice, preferably to 3T MR systems.
Collapse
Affiliation(s)
- Štefan Zbýň
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Vladimír Mlynárik
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Vladimir Juras
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Pavol Szomolanyi
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| |
Collapse
|
113
|
Liu Q, Jin N, Fan Z, Natsuaki Y, Tawackoli W, Pelled G, Bae H, Gazit D, Li D. Reliable chemical exchange saturation transfer imaging of human lumbar intervertebral discs using reduced-field-of-view turbo spin echo at 3.0 T. NMR IN BIOMEDICINE 2013; 26:1672-1679. [PMID: 23893565 DOI: 10.1002/nbm.3001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/06/2013] [Accepted: 06/18/2013] [Indexed: 06/02/2023]
Abstract
The reduced field-of-view (rFOV) turbo-spin-echo (TSE) technique, which effectively suppresses bowel movement artifacts, is developed for the purpose of chemical exchange saturation transfer (CEST) imaging of the intervertebral disc (IVD) in vivo. Attempts to quantify IVD CEST signals in a clinical setting require high reliability and accuracy, which is often compromised in the conventionally used technique. The proposed rFOV TSE CEST method demonstrated significantly superior reproducibility when compared with the conventional technique on healthy volunteers, implying it is a more reliable measurement. Phantom study revealed a linear relation between CEST signal and glycosaminoglycan (GAG) concentration. The feasibility of detecting IVD degeneration was demonstrated on a healthy volunteer, indicating that the proposed method is a promising tool to quantify disc degeneration.
Collapse
Affiliation(s)
- Qi Liu
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
114
|
Abstract
STUDY DESIGN Experimental correlation study design to quantify features of disc health, including signal intensity and distinction between the annulus fibrosus and nucleus pulposus, with T2* magnetic resonance imaging (MRI) and correlate with the functional mechanics in corresponding motion segments. OBJECTIVE Establish the relationship between disc health assessed by quantitative T2* MRI and functional lumbar mechanics. SUMMARY OF BACKGROUND DATA Degeneration leads to altered biochemistry in the disc, affecting the mechanical competence. Clinical routine MRI sequences are not adequate in detecting early changes in degeneration and fails to correlate with pain or improve patient stratification. Quantitative T2* relaxation time mapping probes biochemical features and may offer more sensitivity in assessing disc degeneration. METHODS Cadaveric lumbar spines were imaged using quantitative T2* mapping, as well as conventional T2-weighted MRI sequences. Discs were graded by the Pfirrmann scale, and features of disc health, including signal intensity (T2* intensity area) and distinction between the annulus fibrosus and nucleus pulposus (transition zone slope), were quantified by T2*. Each motion segment was subjected to pure moment bending to determine range of motion (ROM), neutral zone (NZ), and bending stiffness. RESULTS T2* intensity area and transition zone slope were significantly correlated with flexion ROM (P = 0.015; P = 0.002), ratio of NZ/ROM (P = 0.010; P = 0.028), and stiffness (P = 0.044; P = 0.026), as well as lateral bending NZ/ROM (P = 0.005; P = 0.010) and stiffness (P = 0.022; P = 0.029). T2* intensity area was also correlated with lateral bending ROM (P = 0.023). Pfirrmann grade was only correlated with lateral bending NZ/ROM (P = 0.001) and stiffness (P = 0.007). CONCLUSION T2* mapping is a sensitive quantitative method capable of detecting changes associated with disc degeneration. Features of disc health quantified with T2* predicted altered functional mechanics of the lumbar spine better than traditional Pfirrmann grading. This new methodology and analysis technique may enhance the assessment of degeneration and enable greater patient stratification for therapeutic strategies. LEVEL OF EVIDENCE N/A.
Collapse
|
115
|
Zaiss M, Bachert P. Chemical exchange saturation transfer (CEST) and MRZ-spectroscopyin vivo: a review of theoretical approaches and methods. Phys Med Biol 2013; 58:R221-69. [DOI: 10.1088/0031-9155/58/22/r221] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
116
|
Wei W, Jia G, Flanigan D, Zhou J, Knopp MV. Chemical exchange saturation transfer MR imaging of articular cartilage glycosaminoglycans at 3 T: Accuracy of B0 Field Inhomogeneity corrections with gradient echo method. Magn Reson Imaging 2013; 32:41-7. [PMID: 24119460 DOI: 10.1016/j.mri.2013.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/15/2013] [Accepted: 07/21/2013] [Indexed: 11/29/2022]
Abstract
Glycosaminoglycan Chemical Exchange Saturation Transfer (gagCEST) is an important molecular MRI methodology developed to assess changes in cartilage GAG concentrations. The correction for B0 field inhomogeneity is technically crucial in gagCEST imaging. This study evaluates the accuracy of the B0 estimation determined by the dual gradient echo method and the effect on gagCEST measurements. The results were compared with those from the commonly used z-spectrum method. Eleven knee patients and three healthy volunteers were scanned. Dual gradient echo B0 maps with different ∆TE values (1, 2, 4, 8, and 10 ms) were acquired. The asymmetry of the magnetization transfer ratio at 1 ppm offset referred to the bulk water frequency, MTRasym(1 ppm), was used to quantify cartilage GAG levels. The B0 shifts for all knee patients using the z-spectrum and dual gradient echo methods are strongly correlated for all ∆TE values used (r = 0.997 to 0.786, corresponding to ∆TE = 10 to 1 ms). The corrected MTRasym(1 ppm) values using the z-spectrum method (1.34% ± 0.74%) highly agree only with those using the dual gradient echo methods with ∆TE = 10 ms (1.72% ± 0.80%; r = 0.924) and 8 ms (1.50% ± 0.82%; r = 0.712). The dual gradient echo method with longer ∆TE values (more than 8 ms) has an excellent correlation with the z-spectrum method for gagCEST imaging at 3T.
Collapse
Affiliation(s)
- Wenbo Wei
- Wright Center of Innovation in Biomedical Imaging and Department of Radiology, The Ohio State University, Columbus, OH, United States
| | | | | | | | | |
Collapse
|
117
|
Haneder S, Juras V, Michaely HJ, Deligianni X, Bieri O, Schoenberg SO, Trattnig S, Zbýň Š. In vivo sodium (23Na) imaging of the human kidneys at 7 T: Preliminary results. Eur Radiol 2013; 24:494-501. [DOI: 10.1007/s00330-013-3032-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/02/2013] [Accepted: 09/12/2013] [Indexed: 10/26/2022]
|
118
|
Li X, Majumdar S. Quantitative MRI of articular cartilage and its clinical applications. J Magn Reson Imaging 2013; 38:991-1008. [PMID: 24115571 DOI: 10.1002/jmri.24313] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 06/21/2013] [Indexed: 12/27/2022] Open
Abstract
Cartilage is one of the most essential tissues for healthy joint function and is compromised in degenerative and traumatic joint diseases. There have been tremendous advances during the past decade using quantitative MRI techniques as a noninvasive tool for evaluating cartilage, with a focus on assessing cartilage degeneration during osteoarthritis (OA). In this review, after a brief overview of cartilage composition and degeneration, we discuss techniques that grade and quantify morphologic changes as well as the techniques that quantify changes in the extracellular matrix. The basic principles, in vivo applications, advantages, and challenges for each technique are discussed. Recent studies using the OA Initiative (OAI) data are also summarized. Quantitative MRI provides noninvasive measures of cartilage degeneration at the earliest stages of joint degeneration, which is essential for efforts toward prevention and early intervention in OA.
Collapse
Affiliation(s)
- Xiaojuan Li
- Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | | |
Collapse
|
119
|
Baum T, Joseph G, Karampinos D, Jungmann P, Link T, Bauer J. Cartilage and meniscal T2 relaxation time as non-invasive biomarker for knee osteoarthritis and cartilage repair procedures. Osteoarthritis Cartilage 2013; 21:1474-84. [PMID: 23896316 PMCID: PMC3929642 DOI: 10.1016/j.joca.2013.07.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 06/21/2013] [Accepted: 07/17/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The purpose of this work was to review the current literature on cartilage and meniscal T2 relaxation time. METHODS Electronic searches in PubMed were performed to identify relevant studies about T2 relaxation time measurements as non-invasive biomarker for knee osteoarthritis (OA) and cartilage repair procedures. RESULTS Initial osteoarthritic changes include proteoglycan loss, deterioration of the collagen network, and increased water content within the articular cartilage and menisci. T2 relaxation time measurements are affected by these pathophysiological processes. It was demonstrated that cartilage and meniscal T2 relaxation time values were significantly increased in subjects with compared to those without radiographic OA and focal knee lesions, respectively. Subjects with OA risk factors such as overweight/obesity showed significantly greater cartilage T2 values than normal controls. Elevated cartilage and meniscal T2 relaxation times were found in subjects with vs without knee pain. Increased cartilage T2 at baseline predicted morphologic degeneration in the cartilage, meniscus, and bone marrow over 3 years. Furthermore, cartilage repair tissue could be non-invasively assessed by using T2 mapping. Reproducibility errors for T2 measurements were reported to be smaller than the T2 differences in healthy and diseased cartilage indicating that T2 relaxation time may be a reliable discriminatory biomarker. CONCLUSIONS Cartilage and meniscal T2 mapping may be suitable as non-invasive biomarker to diagnose early stages of knee OA and to monitor therapy of OA.
Collapse
Affiliation(s)
- T. Baum
- Institut für Radiologie, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany,Address correspondence and reprint requests to: T. Baum, Institut für Radiologie, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany. Tel: 49-89-4140-2621; Fax: 49-89-4140-4834
| | - G.B. Joseph
- Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA
| | - D.C. Karampinos
- Institut für Radiologie, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany
| | - P.M. Jungmann
- Institut für Radiologie, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany
| | - T.M. Link
- Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA
| | - J.S. Bauer
- Institut für Radiologie, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany,Abteilung für Neuroradiologie, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany
| |
Collapse
|
120
|
Feldman RE, Stobbe R, Watts A, Beaulieu C. Sodium imaging of the human knee using soft inversion recovery fluid attenuation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 234:197-206. [PMID: 23896067 DOI: 10.1016/j.jmr.2013.06.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 06/27/2013] [Accepted: 06/30/2013] [Indexed: 06/02/2023]
Abstract
Sodium signal strength in MRI is low when compared with (1)H. Thus, image voxel volumes must be relatively large in order to produce a sufficient signal-to-noise ratio (SNR). The measurement of sodium in cartilage is hindered by conflation with signal from the adjacent fluid spaces. Inversion recovery can be used to null signal from fluid, but reduces SNR. The purpose of this work was to optimize inversion recovery sodium MRI to enhance cartilage SNR while nulling fluid. Sodium relaxation was first measured for knee cartilage (T1=21±1 ms, T(2 fast)(∗)=0.8±0.2 ms, T(2 slow)(∗)=19.7±0.5 ms) and fluid (T1=48±3 ms, T2(∗)=47±4 ms) in nine healthy subjects at 4.7 T. The rapid relaxation of cartilage in relation to fluid permits the use of a lengthened inversion pulse to preferentially invert the fluid components. Simulations of inversion pulse length were performed to yield a cartilage SNR enhancing combination of parameters that nulled fluid. The simulations were validated in a phantom and then in vivo. B0 inhomogeneity was measured and the effect of off-resonance during the soft inversion pulse was assessed with simulation. Soft inversion recovery yielded twice the SNR and much improved sodium images of cartilage in human knee with little confounding signal from fluid.
Collapse
|
121
|
Ellermann J, Ling W, Nissi MJ, Arendt E, Carlson CS, Garwood M, Michaeli S, Mangia S. MRI rotating frame relaxation measurements for articular cartilage assessment. Magn Reson Imaging 2013; 31:1537-43. [PMID: 23993794 DOI: 10.1016/j.mri.2013.06.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 06/03/2013] [Accepted: 06/08/2013] [Indexed: 12/20/2022]
Abstract
In the present work we introduced two MRI rotating frame relaxation methods, namely adiabatic T1ρ and Relaxation Along a Fictitious Field (RAFF), along with an inversion-prepared Magnetization Transfer (MT) protocol for assessment of articular cartilage. Given the inherent sensitivity of rotating frame relaxation methods to slow molecular motions that are relevant in cartilage, we hypothesized that adiabatic T1ρ and RAFF would have higher sensitivity to articular cartilage degradation as compared to laboratory frame T2 and MT. To test this hypothesis, a proteoglycan depletion model was used. Relaxation time measurements were performed at 0 and 48h in 10 bovine patellar specimens, 5 of which were treated with trypsin and 5 untreated controls were stored under identical conditions in isotonic saline for 48h. Relaxation times measured at 48h were longer than those measured at 0h in both groups. The changes in T2 and MT relaxation times after 48h were approximately 3 times larger in the trypsin treated specimens as compared to the untreated group, whereas increases of adiabatic T1ρ and RAFF were 4 to 5 fold larger. Overall, these findings demonstrate a higher sensitivity of adiabatic T1ρ and RAFF to the trypsin-induced changes in bovine patellar cartilage as compared to the commonly used T2 and MT. Since adiabatic T1ρ and RAFF are advantageous for human applications as compared to standard continuous-wave T1ρ methods, adiabatic T1ρ and RAFF are promising tools for assessing cartilage degradation in clinical settings.
Collapse
Affiliation(s)
- Jutta Ellermann
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, USA.
| | | | | | | | | | | | | | | |
Collapse
|
122
|
Palmer AJR, Brown CP, McNally EG, Price AJ, Tracey I, Jezzard P, Carr AJ, Glyn-Jones S. Non-invasive imaging of cartilage in early osteoarthritis. Bone Joint J 2013; 95-B:738-46. [PMID: 23723266 DOI: 10.1302/0301-620x.95b6.31414] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Treatment for osteoarthritis (OA) has traditionally focused on joint replacement for end-stage disease. An increasing number of surgical and pharmaceutical strategies for disease prevention have now been proposed. However, these require the ability to identify OA at a stage when it is potentially reversible, and detect small changes in cartilage structure and function to enable treatment efficacy to be evaluated within an acceptable timeframe. This has not been possible using conventional imaging techniques but recent advances in musculoskeletal imaging have been significant. In this review we discuss the role of different imaging modalities in the diagnosis of the earliest changes of OA. The increasing number of MRI sequences that are able to non-invasively detect biochemical changes in cartilage that precede structural damage may offer a great advance in the diagnosis and treatment of this debilitating condition.
Collapse
Affiliation(s)
- A J R Palmer
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Windmill Road, Headington OX3 7LD, UK
| | | | | | | | | | | | | | | |
Collapse
|
123
|
Matzat SJ, van Tiel J, Gold GE, Oei EHG. Quantitative MRI techniques of cartilage composition. Quant Imaging Med Surg 2013; 3:162-74. [PMID: 23833729 DOI: 10.3978/j.issn.2223-4292.2013.06.04] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 06/24/2013] [Indexed: 12/15/2022]
Abstract
Due to aging populations and increasing rates of obesity in the developed world, the prevalence of osteoarthritis (OA) is continually increasing. Decreasing the societal and patient burden of this disease motivates research in prevention, early detection of OA, and novel treatment strategies against OA. One key facet of this effort is the need to track the degradation of tissues within joints, especially cartilage. Currently, conventional imaging techniques provide accurate means to detect morphological deterioration of cartilage in the later stages of OA, but these methods are not sensitive to the subtle biochemical changes during early disease stages. Novel quantitative techniques with magnetic resonance imaging (MRI) provide direct and indirect assessments of cartilage composition, and thus allow for earlier detection and tracking of OA. This review describes the most prominent quantitative MRI techniques to date-dGEMRIC, T2 mapping, T1rho mapping, and sodium imaging. Other, less-validated methods for quantifying cartilage composition are also described-Ultrashort echo time (UTE), gagCEST, and diffusion-weighted imaging (DWI). For each technique, this article discusses the proposed biochemical correlates, as well its advantages and limitations for clinical and research use. The article concludes with a detailed discussion of how the field of quantitative MRI has progressed to provide information regarding two specific patient populations through clinical research-patients with anterior cruciate ligament rupture and patients with impingement in the hip. While quantitative imaging techniques continue to rapidly evolve, specific challenges for each technique as well as challenges to clinical applications remain.
Collapse
|
124
|
Nagarajan MB, Coan P, Huber MB, Diemoz PC, Glaser C, Wismuller A. Computer-aided diagnosis in phase contrast imaging X-ray computed tomography for quantitative characterization of ex vivo human patellar cartilage. IEEE Trans Biomed Eng 2013; 60:2896-903. [PMID: 23744660 DOI: 10.1109/tbme.2013.2266325] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Visualization of ex vivo human patellar cartilage matrix through the phase contrast imaging X-ray computed tomography (PCI-CT) has been previously demonstrated. Such studies revealed osteoarthritis-induced changes to chondrocyte organization in the radial zone. This study investigates the application of texture analysis to characterizing such chondrocyte patterns in the presence and absence of osteoarthritic damage. Texture features derived from Minkowski functionals (MF) and gray-level co-occurrence matrices (GLCM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These texture features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). The best classification performance was observed with the MF features perimeter (AUC: 0.94 ±0.08 ) and "Euler characteristic" (AUC: 0.94 ±0.07 ), and GLCM-derived feature "Correlation" (AUC: 0.93 ±0.07). These results suggest that such texture features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix, enabling classification of cartilage as healthy or osteoarthritic with high accuracy.
Collapse
|
125
|
Kogan F, Hariharan H, Reddy R. Chemical Exchange Saturation Transfer (CEST) Imaging: Description of Technique and Potential Clinical Applications. CURRENT RADIOLOGY REPORTS 2013; 1:102-114. [PMID: 23730540 PMCID: PMC3665411 DOI: 10.1007/s40134-013-0010-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chemical exchange saturation transfer (CEST) is a magnetic resonance imaging (MRI) contrast enhancement technique that enables indirect detection of metabolites with exchangeable protons. Endogenous metabolites with exchangeable protons including many endogenous proteins with amide protons, glycosaminoglycans (GAG), glycogen, myo-inositol (MI), glutamate (Glu), creatine (Cr) and several others have been identified as potential in vivo endogenous CEST agents. These endogenous CEST agents can be exploited as non-invasive and non-ionizing biomarkers of disease diagnosis and treatment monitoring. This review focuses on the recent technical developments in endogenous in vivo CEST MRI from various metabolites as well as their potential clinical applications. The basic underlying principles of CEST, its potential limitations and new techniques to mitigate them are discussed.
Collapse
Affiliation(s)
- Feliks Kogan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
| |
Collapse
|
126
|
Kotecha M, Ravindran S, Schmid TM, Vaidyanathan A, George A, Magin RL. Application of sodium triple-quantum coherence NMR spectroscopy for the study of growth dynamics in cartilage tissue engineering. NMR IN BIOMEDICINE 2013; 26:709-17. [PMID: 23378198 PMCID: PMC3634872 DOI: 10.1002/nbm.2916] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 10/23/2012] [Accepted: 12/09/2012] [Indexed: 06/01/2023]
Abstract
We studied the tissue growth dynamics of tissue-engineered cartilage at an early growth stage after cell seeding for four weeks using sodium triple-quantum coherence NMR spectroscopy. The following tissue-engineering constructs were studied: 1) bovine chondrocytes cultured in alginate beads; 2) bovine chondrocytes cultured as pellets (scaffold-free chondrocyte pellets); and 3) human marrow stromal cells (HMSCs) seeded in collagen/chitosan based biomimetic scaffolds. We found that the sodium triple-quantum coherence spectroscopy could differentiate between different tissue-engineered constructs and native tissues based on the fast and slow components of relaxation rate as well as on the average quadrupolar coupling. Both fast (Tf ) and slow (Ts ) relaxation times were found to be longer in chondrocyte pellets and biomimetic scaffolds compared to chondrocytes suspended in alginate beads and human articular cartilage tissues. In all cases, it was found that relaxation rates and motion of sodium ions measured from correlation times were dependent on the amount of macromolecules, high cell density and anisotropy of the cartilage tissue-engineered constructs. Average quadrupolar couplings were found to be lower in the engineered tissue compared to native tissue, presumably due to the lack of order in collagen accumulated in the engineered tissue. These results support the use of sodium triple-quantum coherence spectroscopy as a tool to investigate anisotropy and growth dynamics of cartilage tissue-engineered constructs in a simple and reliable way.
Collapse
Affiliation(s)
- Mrignayani Kotecha
- Department of Bioengineering, University of Illinois at Chicago, IL 60607, USA.
| | | | | | | | | | | |
Collapse
|
127
|
Polders DL, Hoogduin JM. Chemical Exchange Saturation Transfer MR Imaging: Potential Clinical Applications. PET Clin 2013; 8:245-57. [PMID: 27158068 DOI: 10.1016/j.cpet.2013.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Chemical exchange saturation transfer (CEST) measurements hold great promise as the next step in magnetization transfer imaging and possibly allow for in vivo quantification of many clinically relevant parameters, including pH, temperature, and amide concentration. Therefore, it is a valuable method to add to the MR imaging toolbox. The aim of this article was to review the methods for the acquisition of CEST data and necessary postprocessing. CEST research is very much a field still in development, and initial explorations in clinical applications are shown to illustrate the potential of CEST as a new contrast mechanism.
Collapse
Affiliation(s)
- Daniel Louis Polders
- Imaging Division, Department of Radiology, UMCU, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Johannes Marinus Hoogduin
- Imaging Division, Department of Radiology, UMCU, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands; Brain Division, UMCU, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
| |
Collapse
|
128
|
Chang G, Xia D, Sherman O, Strauss E, Jazrawi L, Recht MP, Regatte RR. High resolution morphologic imaging and T2 mapping of cartilage at 7 Tesla: comparison of cartilage repair patients and healthy controls. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2013; 26:539-48. [PMID: 23657612 DOI: 10.1007/s10334-013-0379-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/20/2013] [Accepted: 04/22/2013] [Indexed: 11/26/2022]
Abstract
OBJECT Our objective was to use 7 T MRI to compare cartilage morphology (thickness) and collagen composition (T2 values) in cartilage repair patients and healthy controls. MATERIALS AND METHODS We scanned the knees of 11 cartilage repair patients and 11 controls on a 7 T MRI scanner using a high-resolution, gradient-echo sequence to measure cartilage thickness and a multi-echo spin-echo sequence to measure cartilage T2 values. We used two-tailed t tests to compare cartilage thickness and T2 values in: repair tissue (RT) versus adjacent cartilage (AC); RT versus healthy control cartilage (HC); AC versus HC. RESULTS Mean thickness in RT, AC, HC were: 2.2±1.4, 3.6±1.1, 3.3±0.7 mm. Differences in thickness between RT-AC (p=0.01) and RT-HC (p=0.02) were significant, but not AC-HC (p=0.45). Mean T2 values in RT, AC, HC were: 51.6±7.6, 40.0±4.7, 45.9±3.7 ms. Differences in T2 values between RT-AC (p=0.0005), RT-HC (p=0.04), and AC-HC (p=0.004) were significant. CONCLUSION 7 T MRI allows detection of differences in morphology and collagen architecture in: (1) cartilage repair tissue compared to adjacent cartilage and (2) cartilage repair tissue compared to cartilage from healthy controls. Although cartilage adjacent to repair tissue may be normal in thickness, it can demonstrate altered collagen composition.
Collapse
Affiliation(s)
- Gregory Chang
- Department of Radiology, NYU Langone Medical Center, Center for Musculoskeletal Care, 333 East 38th Street, 6th Floor, Room 610, New York, NY, 10016, USA,
| | | | | | | | | | | | | |
Collapse
|
129
|
Zhou J, Hong X, Zhao X, Gao JH, Yuan J. APT-weighted and NOE-weighted image contrasts in glioma with different RF saturation powers based on magnetization transfer ratio asymmetry analyses. Magn Reson Med 2013; 70:320-7. [PMID: 23661598 DOI: 10.1002/mrm.24784] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Revised: 03/11/2013] [Accepted: 04/03/2013] [Indexed: 12/27/2022]
Abstract
PURPOSE To investigate the saturation-power dependence of amide proton transfer (APT)-weighted and nuclear Overhauser enhancement-weighted image contrasts in a rat glioma model at 4.7 T. METHODS The 9L tumor-bearing rats (n = 8) and fresh chicken eggs (n = 4) were scanned on a 4.7-T animal magnetic resonance imaging scanner. Z-spectra over an offset range of ±6 ppm were acquired with different saturation powers, followed by the magnetization transfer-ratio asymmetry analyses around the water resonance. RESULTS The nuclear Overhauser enhancement signal upfield from the water resonance (-2.5 to -5 ppm) was clearly visible at lower saturation powers (e.g., 0.6 µT) and was larger in the contralateral normal brain tissue than in the tumor. Conversely, the APT effect downfield from the water resonance was maximized at relatively higher saturation powers (e.g., 2.1 µT) and was larger in the tumor than in the contralateral normal brain tissue. The nuclear Overhauser enhancement decreased the APT-weighted image signal, based on the magnetization transfer-ratio asymmetry analysis, but increased the APT-weighted image contrast between the tumor and contralateral normal brain tissue. CONCLUSION The APT and nuclear Overhauser enhancement image signals in tumor are maximized at different saturation powers. The saturation power of roughly 2 μT is ideal for APT-weighted imaging at clinical B0 field strengths.
Collapse
Affiliation(s)
- Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.
| | | | | | | | | |
Collapse
|
130
|
Zaiss M, Bachert P. Exchange-dependent relaxation in the rotating frame for slow and intermediate exchange -- modeling off-resonant spin-lock and chemical exchange saturation transfer. NMR IN BIOMEDICINE 2013; 26:507-18. [PMID: 23281186 DOI: 10.1002/nbm.2887] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 05/17/2023]
Abstract
Chemical exchange observed by NMR saturation transfer (CEST) and spin-lock (SL) experiments provide an MRI contrast by indirect detection of exchanging protons. The determination of the relative concentrations and exchange rates is commonly achieved by numerical integration of the Bloch-McConnell equations. We derive an analytical solution of the Bloch-McConnell equations that describes the magnetization of coupled spin populations under radiofrequency irradiation. As CEST and off-resonant SL are equivalent, their steady-state magnetization and dynamics can be predicted by the same single eigenvalue: the longitudinal relaxation rate in the rotating frame R1ρ . For the case of slowly exchanging systems, e.g. amide protons, the saturation of the small proton pool is affected by transverse relaxation (R2b ). It turns out, that R2b is also significant for intermediate exchange, such as amine- or hydroxyl-exchange or paramagnetic CEST agents, if pools are only partially saturated. We propose a solution for R1ρ that includes R2 of the exchanging pool by extending existing approaches, and verify it by numerical simulations. With the appropriate projection factors, we obtain an analytical solution for CEST and SL for nonzero R2 of the exchanging pool, exchange rates in the range 1-10(4) Hz, B1 from 0.1 to 20 μT and arbitrary chemical shift differences between the exchanging pools, whilst considering the dilution by direct water saturation across the entire Z-spectra. This allows the optimization of irradiation parameters and the quantification of pH-dependent exchange rates and metabolite concentrations. In addition, we propose evaluation methods that correct for concomitant direct saturation effects. It is shown that existing theoretical treatments for CEST are special cases of this approach.
Collapse
Affiliation(s)
- Moritz Zaiss
- Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | | |
Collapse
|
131
|
Binks DA, Hodgson RJ, Ries ME, Foster RJ, Smye SW, McGonagle D, Radjenovic A. Quantitative parametric MRI of articular cartilage: a review of progress and open challenges. Br J Radiol 2013; 86:20120163. [PMID: 23407427 DOI: 10.1259/bjr.20120163] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
With increasing life expectancies and the desire to maintain active lifestyles well into old age, the impact of the debilitating disease osteoarthritis (OA) and its burden on healthcare services is mounting. Emerging regenerative therapies could deliver significant advances in the effective treatment of OA but rely upon the ability to identify the initial signs of tissue damage and will also benefit from quantitative assessment of tissue repair in vivo. Continued development in the field of quantitative MRI in recent years has seen the emergence of techniques able to probe the earliest biochemical changes linked with the onset of OA. Quantitative MRI measurements including T(1), T(2) and T(1ρ) relaxometry, diffusion weighted imaging and magnetisation transfer have been studied and linked to the macromolecular structure of cartilage. Delayed gadolinium-enhanced MRI of cartilage, sodium MRI and glycosaminoglycan chemical exchange saturation transfer techniques are sensitive to depletion of cartilage glycosaminoglycans and may allow detection of the earliest stages of OA. We review these current and emerging techniques for the diagnosis of early OA, evaluate the progress that has been made towards their implementation in the clinic and identify future challenges in the field.
Collapse
Affiliation(s)
- D A Binks
- Section of Musculoskeletal Disease, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK
| | | | | | | | | | | | | |
Collapse
|
132
|
Vinogradov E, Sherry AD, Lenkinski RE. CEST: from basic principles to applications, challenges and opportunities. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 229:155-72. [PMID: 23273841 PMCID: PMC3602140 DOI: 10.1016/j.jmr.2012.11.024] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/18/2012] [Accepted: 11/20/2012] [Indexed: 05/03/2023]
Abstract
Chemical Exchange Saturation Transfer (CEST) offers a new type of contrast for MRI that is molecule specific. In this approach, a slowly exchanging NMR active nucleus, typically a proton, possessing a chemical shift distinct from water is selectively saturated and the saturated spin is transferred to the bulk water via chemical exchange. Many molecules can act as CEST agents, both naturally occurring endogenous molecules and new types of exogenous agents. A large variety of molecules have been demonstrated as potential agents, including small diamagnetic molecules, complexes of paramagnetic ions, endogenous macromolecules, dendrimers and liposomes. In this review we described the basic principles of the CEST experiment, with emphasis on the similarity to earlier saturation transfer experiments described in the literature. Interest in quantitative CEST has also resulted in the development of new exchange-sensitive detection schemes. Some emerging clinical applications of CEST are described and the challenges and opportunities associated with translation of these methods to the clinical environment are discussed.
Collapse
Affiliation(s)
- Elena Vinogradov
- Department of Radiology and Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | | | | |
Collapse
|
133
|
Buchbender C, Schneider M, Ostendorf B. Magnetresonanztomographie und Hybridbildgebung in der Rheumatologie. Z Rheumatol 2013; 72:137-44. [DOI: 10.1007/s00393-012-1068-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
134
|
Zhou J, Zhu H, Lim M, Blair L, Quinones-Hinojosa A, Messina SA, Eberhart CG, Pomper MG, Laterra J, Barker PB, van Zijl PCM, Blakeley JO. Three-dimensional amide proton transfer MR imaging of gliomas: Initial experience and comparison with gadolinium enhancement. J Magn Reson Imaging 2013; 38:1119-28. [PMID: 23440878 DOI: 10.1002/jmri.24067] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 01/10/2013] [Indexed: 01/31/2023] Open
Abstract
PURPOSE To investigate the feasibility of a three-dimensional amide-proton-transfer (APT) imaging sequence with gradient- and spin-echo readouts at 3 Tesla in patients with high- or low-grade gliomas. MATERIALS AND METHODS Fourteen patients with newly diagnosed gliomas were recruited. After B0 inhomogeneity correction on a voxel-by-voxel basis, APT-weighted images were reconstructed using a magnetization-transfer-ratio asymmetry at offsets of ±3.5 ppm with respect to the water resonance. Analysis of variance post hoc tests were used for statistical evaluations, and results were validated with pathology. RESULTS In six patients with gadolinium-enhancing high-grade gliomas, enhancing tumors on the postcontrast T1 -weighted images were consistently hyperintense on the APT-weighted images. Increased APT-weighted signal intensity was also clearly visible in two pathologically proven, high-grade gliomas without gadolinium enhancement. The average APT-weighted signal was significantly higher in the lesions than in the contralateral normal-appearing brain tissue (P < 0.001). In six low-grade gliomas, including two with gadolinium enhancement, APT-weighted imaging showed iso-intensity or mild punctate hyperintensity within all the lesions, which was significantly lower than that seen in the high-grade gliomas (P < 0.001). CONCLUSION The proposed three-dimensional APT imaging sequence can be incorporated into standard brain MRI protocols for patients with malignant gliomas.
Collapse
Affiliation(s)
- Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
135
|
Liu D, Zhou J, Xue R, Zuo Z, An J, Wang DJJ. Quantitative characterization of nuclear overhauser enhancement and amide proton transfer effects in the human brain at 7 tesla. Magn Reson Med 2012; 70:1070-81. [PMID: 23238951 DOI: 10.1002/mrm.24560] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/27/2012] [Accepted: 10/24/2012] [Indexed: 12/27/2022]
Abstract
PURPOSE This study aimed to quantitatively investigate two main magnetization transfer effects at low B1: the nuclear Overhauser enhancement (NOE) and amide proton transfer in the human brain at 7 T. METHODS The magnetization transfer effects in the human brain were characterized using a four-pool proton model, which consisted of bulk water, macromolecules, an amide group of mobile proteins and peptides, and NOE-related protons resonating upfield. The pool sizes, exchange rates, and relaxation times of these proton pools were investigated quantitatively by fitting, and the net signals of amide proton transfer and NOE were simulated based on the fitted parameters. RESULTS The results showed that the four-pool model fitted the experimental data quite well, and the NOE effects in human brain at 7 T had a broad spectrum distribution. The NOE effects peaked at a B1 of ∼ 1-1.4 μT and were significantly stronger in the white matter than in the gray matter, corresponding to a pool-size ratio ∼ 2:1. As the amide proton transfer effect was relatively small compared with the NOE effects, magnetization transfer asymmetry analysis yielded an NOE-dominated contrast in the healthy human brain in this range of B1. CONCLUSION These findings are important to identify the source of NOE effects and to quantify amide proton transfer effects in human brain at 7 T.
Collapse
Affiliation(s)
- Dapeng Liu
- State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing, China and Los Angeles, California, USA; Graduate University, Chinese Academy of Sciences, Beijing, China
| | | | | | | | | | | |
Collapse
|
136
|
Miese F, Buchbender C, Scherer A, Wittsack HJ, Specker C, Schneider M, Antoch G, Ostendorf B. Molecular imaging of cartilage damage of finger joints in early rheumatoid arthritis with delayed gadolinium-enhanced magnetic resonance imaging. ACTA ACUST UNITED AC 2012; 64:394-9. [PMID: 21952736 DOI: 10.1002/art.33352] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To assess cartilage glycosaminoglycan content and cartilage thickness in the metacarpophalangeal (MCP) joints of patients with early rheumatoid arthritis (RA) and healthy volunteers. METHODS After review board approval and informed consent were obtained, 22 subjects were prospectively enrolled (9 patients with early RA [7 women and 2 men with a mean ± SD age of 49 ± 13 years; range 25-68 years] and 13 healthy volunteers [10 women and 3 men with a mean ± SD age of 51 ± 12 years; range 25-66 years). In a total of 44 MCP joints of the index and middle fingers, measurements of cartilage thickness and delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) index (T1 [msec]) were obtained using the variable flip-angle method and a 3T MR scanner. MRIs were evaluated for bone edema, erosions, and synovitis (using the RA MRI Scoring criteria). Student's t-test was used to test the significance of differences between groups. RESULTS The mean ± SD dGEMRIC index was 497 ± 86 msec in healthy volunteers and was significantly lower in the early RA group (421 ± 76 msec) (P = 0.042). There was no joint space narrowing seen on standard radiographs. No significant difference was found between cartilage thickness in patients with early RA and that in controls (index finger mean ± SD 1.27 ± 0.23 mm in RA patients versus 1.46 ± 0.34 mm in controls [P = 0.16] and middle finger 1.26 ± 0.23 mm in RA patients versus 0.97 ± 0.47 mm in controls [P = 0.10]). No significant correlation was noted between cartilage thickness and dGEMRIC index (R = 0.36, P = 0.88 in RA patients; R = 0.156, P = 0.445 in controls). CONCLUSION Our findings indicate that cartilage damage is present in the MCP joints of patients with early RA despite the absence of joint space narrowing on standard radiographs and MRI. Cartilage damage in RA can be imaged with dGEMRIC.
Collapse
Affiliation(s)
- Falk Miese
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany
| | | | | | | | | | | | | | | |
Collapse
|
137
|
Jin T, Kim SG. Quantitative chemical exchange sensitive MRI using irradiation with toggling inversion preparation. Magn Reson Med 2012; 68:1056-64. [PMID: 22887701 DOI: 10.1002/mrm.24449] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 06/11/2012] [Accepted: 07/11/2012] [Indexed: 11/07/2022]
Abstract
Chemical exchange (CE) sensitive MRI contrast acquired with an off-resonance irradiation pulse is affected by other relaxation mechanisms, such as longitudinal and transverse relaxations. In particular, for intermediate CEs, the effect of transverse relaxation often dominates CE contrast. Since water relaxation rates can change significantly in many pathological conditions or during physiological challenge, it is crucial to separate these relaxation effects in order to obtain pure CE contrast. Here we proposed a novel acquisition scheme in which a toggling inversion pulse is applied prior to the off-resonance irradiation. By combined acquisition of irradiation images with and without an inversion pulse at both the labile proton frequency and the reference frequency, longitudinal and transverse relaxation contributions are cancelled, and the quantification of CE parameters, such as the exchange rate and the labile proton concentration, can be simplified. Furthermore, the CE-mediated relaxation rate can be readily determined with a relatively short irradiation pulse and without approaching the steady state, therefore, reducing the limitations on hardware and specific absorption rate requirements. The signal characteristics of the proposed method are evaluated by numerical simulations and phantom experiments.
Collapse
Affiliation(s)
- Tao Jin
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15203, USA.
| | | |
Collapse
|
138
|
Zbýň S, Stelzeneder D, Welsch GH, Negrin LL, Juras V, Mayerhoefer ME, Szomolanyi P, Bogner W, Domayer SE, Weber M, Trattnig S. Evaluation of native hyaline cartilage and repair tissue after two cartilage repair surgery techniques with 23Na MR imaging at 7 T: initial experience. Osteoarthritis Cartilage 2012; 20:837-45. [PMID: 22548796 DOI: 10.1016/j.joca.2012.04.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 04/15/2012] [Accepted: 04/24/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare the sodium normalized mean signal intensity (NMSI) values between patients after bone marrow stimulation (BMS) and matrix-associated autologous chondrocyte transplantation (MACT) cartilage repair procedures. METHODS Nine BMS and nine MACT patients were included. Each BMS patient was matched with one MACT patient according to age [BMS 36.7 ± 10.7 (mean ± standard deviation) years; MACT 36.9 ± 10.0 years], postoperative interval (BMS 33.5 ± 25.3 months; MACT 33.2 ± 25.7 months), and defect location. All magnetic resonance imaging (MRI) measurements were performed on a 7 T system. Proton images served for morphological evaluation of repair tissue using the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system. Sodium NMSI values in the repair area and morphologically normal cartilage were calculated. Clinical outcome was assessed right after MRI. Analysis of covariance, t-tests, and Pearson correlation coefficients were evaluated. RESULTS Sodium NMSI was significantly lower in BMS (P = 0.004) and MACT (P = 0.006) repair tissue, compared to reference cartilage. Sodium NMSI was not different between the reference cartilage in MACT and BMS patients (P = 0.664), however it was significantly higher in MACT than in BMS repair tissue (P = 0.028). Better clinical outcome was observed in BMS than in MACT patients. There was no difference between MOCART scores for MACT and BMS patients (P = 0.915). We did not observe any significant correlation between MOCART score and sodium repair tissue NMSI (r = -0.001; P = 0.996). CONCLUSIONS Our results suggest higher glycosaminoglycan (GAG) content, and therefore, repair tissue of better quality in MACT than in BMS patients. Sodium imaging might be beneficial in non-invasive evaluation of cartilage repair surgery efficacy.
Collapse
Affiliation(s)
- S Zbýň
- MR Centre-Highfield MR, Department of Radiology, Medical University of Vienna/Vienna General Hospital, Vienna, Austria.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
139
|
Advanced MR methods at ultra-high field (7 Tesla) for clinical musculoskeletal applications. Eur Radiol 2012; 22:2338-46. [DOI: 10.1007/s00330-012-2508-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 05/02/2012] [Accepted: 05/04/2012] [Indexed: 12/16/2022]
|
140
|
Long-term results 8 years after autologous osteochondral transplantation: 7 T gagCEST and sodium magnetic resonance imaging with morphological and clinical correlation. Osteoarthritis Cartilage 2012; 20:357-363. [PMID: 22353692 DOI: 10.1016/j.joca.2012.01.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 01/02/2012] [Accepted: 01/28/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To correlate long-term clinical outcome and the results of morphological as well as advanced biochemical magnetic resonance imaging (MRI) techniques [T2-mapping, glycosaminoglycan chemical exchange saturation transfer (gagCEST), sodium-23-imaging] in patients after autologous osteochondral transplantation (AOT) in knee joints. METHOD Nine AOT patients (two female and seven male; median age, 49) had clinical [International Knee Documentation Committee (IKDC), modified Lysholm, visual analog scale (VAS)] and radiological long-term follow-up examinations at a median of 7.9 years (inter-quartile range, 7.7-8.2). Standard morphological MRI and T2-mapping of cartilage were performed on a 3 T MR unit. Biochemical imaging further included sodium-23-imaging and chemical exchange saturation transfer (CEST) imaging at 7 T. The Magnetic resonance Observation of CArtilage Repair Tissue (MOCART) score was used for quantitative assessment of morphological MRI. RESULTS Clinical outcome was good with a median modified Lysholm score of 90. Median VAS revealed 1.0 and median MOCART score 75 points. The difference between native and repair cartilage was statistically significant for all three biochemical imaging techniques. The strongest correlation was found between the results of the advanced biochemical imaging methods sodium-23 and CEST [ρ = 0.952, 95% confidence interval (CI): (0.753; 0.992)]. Comparing the results from morphological and biochemical imaging, a correlation was found between MOCART score and CEST ratio [ρ = -0.749, 95% CI: (-0.944; -0.169)]. Comparing the results from clinical scores with MRI, a correlation between modified Lysholm and T2-mapping [ρ = -0.667, 95% CI: (-0.992; -0.005)] was observed. CONCLUSION Long-term clinical outcome in patients 7.9 years after AOT was good, but did not correlate with morphological and biochemical imaging results except for T2-mapping.
Collapse
|
141
|
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.
Collapse
|
142
|
Chang G, Madelin G, Sherman OH, Strauss EJ, Xia D, Recht MP, Jerschow A, Regatte RR. Improved assessment of cartilage repair tissue using fluid-suppressed ²³Na inversion recovery MRI at 7 Tesla: preliminary results. Eur Radiol 2012; 22:1341-9. [PMID: 22350437 DOI: 10.1007/s00330-012-2383-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 12/05/2011] [Accepted: 12/07/2011] [Indexed: 10/28/2022]
Abstract
OBJECTIVES To evaluate cartilage repair and native tissue using a three-dimensional (3D), radial, ultra-short echo time (UTE) (23)Na MR sequence without and with an inversion recovery (IR) preparation pulse for fluid suppression at 7 Tesla (T). METHODS This study had institutional review board approval. We recruited 11 consecutive patients (41.5 ± 11.8 years) from an orthopaedic surgery practice who had undergone a knee cartilage restoration procedure. The subjects were examined postoperatively (median = 26 weeks) with 7-T MRI using: proton-T2 (TR/TE = 3,000 ms/60 ms); sodium UTE (TR/TE = 100 ms/0.4 ms); fluid-suppressed, sodium UTE adiabatic IR. Cartilage sodium concentrations in repair tissue ([Na(+)](R)), adjacent native cartilage ([Na(+)](N)), and native cartilage within the opposite, non-surgical compartment ([Na(+)](N2)) were calculated using external NaCl phantoms. RESULTS For conventional sodium imaging, mean [Na(+)](R), [Na(+)](N), [Na(+)](N2) were 177.8 ± 54.1 mM, 170.1 ± 40.7 mM, 172.2 ± 30 mM respectively. Differences in [Na(+)](R) versus [Na(+)](N) (P = 0.59) and [Na(+)](N) versus [Na(+)](N2) (P = 0.89) were not significant. For sodium IR imaging, mean [Na(+)](R), [Na(+)](N), [Na(+)](N2) were 108.9 ± 29.8 mM, 204.6 ± 34.7 mM, 249.9 ± 44.6 mM respectively. Decreases in [Na(+)](R) versus [Na(+)](N) (P = 0.0.0000035) and [Na(+)](N) versus [Na(+)](N2) (P = 0.015) were significant. CONCLUSIONS Sodium IR imaging at 7 T can suppress the signal from free sodium within synovial fluid. This may allow improved assessment of [Na(+)] within cartilage repair and native tissue. KEY POINTS • NaIR magnetic resonance imaging can suppress signal from sodium within synovial fluid. • NaIR MRI thus allows assessment of sodium concentration within cartilage tissue alone. • This may facilitate more accurate assessment of repair tissue composition and quality.
Collapse
Affiliation(s)
- Gregory Chang
- Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, Department of Radiology, NYU Langone Medical Center, 660 First Avenue, New York, NY 10016, USA.
| | | | | | | | | | | | | | | |
Collapse
|
143
|
Singh A, Haris M, Cai K, Kassey VB, Kogan F, Reddy D, Hariharan H, Reddy R. Chemical exchange saturation transfer magnetic resonance imaging of human knee cartilage at 3 T and 7 T. Magn Reson Med 2011; 68:588-94. [PMID: 22213239 DOI: 10.1002/mrm.23250] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/12/2011] [Accepted: 09/16/2011] [Indexed: 11/10/2022]
Abstract
The sensitivity of chemical exchange saturation transfer (CEST) on glycosaminoglycans (GAGs) in human knee cartilage (gagCEST) in vivo was evaluated at 3 and 7 T field strengths. Calculated gagCEST values without accounting for B(0) inhomogeneity (~0.6 ppm) were >20%. After B(0) inhomogeneity correction, calculated gagCEST values were negligible at 3 T and ~6% at 7 T. These results suggest that accurate B(0) correction is a prerequisite for observing reliable gagCEST. Results obtained with varying saturation pulse durations and amplitudes as well as the consistency between numerical simulations and our experimental results indicate that the negligible gagCEST observed at 3 T is due to direct saturation effects and fast exchange rate. As GAG loss from cartilage is expected to result in a further reduction in gagCEST, gagCEST method is not expected to be clinically useful at 3 T. At high fields such as 7 T, this method holds promise as a viable clinical technique.
Collapse
Affiliation(s)
- Anup Singh
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, United States.
| | | | | | | | | | | | | | | |
Collapse
|
144
|
Thakkar RS, Subhawong T, Carrino JA, Chhabra A. Cartilage magnetic resonance imaging techniques at 3 T: current status and future directions. Top Magn Reson Imaging 2011; 22:71-81. [PMID: 22648082 DOI: 10.1097/rmr.0b013e318259ff95] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Magnetic resonance imaging (MRI) remains the imaging modality of choice for morphological and compositional evaluation of the articular cartilage. Accurate detection and characterization of cartilage lesions are necessary to guide the medical and surgical therapy and are also critical for longitudinal studies of the cartilage. Recent work using 3.0-T MRI systems shows promise in improving detection and characterization of the cartilage lesions, particularly with increasing use of high-resolution and high-contrast 3-dimensional sequences, which allow detailed morphological assessment of cartilage in arbitrary imaging planes. In addition, implementation of biochemical sequences in clinically feasible scan times has a potential in the early detection of cartilage lesions before they become morphologically apparent. This article discusses relative advantages and disadvantages of various commonly used as well as experimental MRI techniques to directly assess the morphology and indirectly evaluate the biochemical composition of the articular cartilage.
Collapse
Affiliation(s)
- Rashmi S Thakkar
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University-School of Medicine, Baltimore, MD 21287, USA
| | | | | | | |
Collapse
|