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Harkins KD, Ketsiri T, Nyman JS, Does MD. Fast bound and pore water mapping of cortical bone with arbitrary slice oriented two-dimensional ultra-short echo time. Magn Reson Med 2023; 89:767-773. [PMID: 36226656 PMCID: PMC9897494 DOI: 10.1002/mrm.29484] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/07/2022] [Accepted: 09/20/2022] [Indexed: 02/05/2023]
Abstract
PURPOSE Extend fast, two-dimensional (2D) methods of bound and pore water mapping in bone to arbitrary slice orientation. METHODS To correct for slice profile artifacts caused by gradient errors of half pulse 2D ultra-short echo time (UTE), we developed a library of predistorted gradient waveforms that can be used to interpolate optimized gradient waveforms for 2D UTE slice selection. We also developed a method to estimate and correct for a bulk phase difference between the two half pulse excitations used for 2D UTE signal excitation. Bound water images were acquired in three healthy subjects with adiabatic inversion recovery prepared 2D UTE, while pore water images were acquired after short-T2 signals were suppressed with double adiabatic inversion recovery preparation. The repeatability of bound and pore water imaging with 2D UTE was tested by repeating acquisitions after repositioning. RESULTS The library-based interpolation of optimized slice select gradient waveforms combined with the method to estimate bulk phase between two excitations provided compact slice profiles for half pulse excited 2D UTE. Quantitative bound and pore water values were highly repeatable-the pooled SD of bound water across all three subjects was 0.38 mol1 $$ {}^1 $$ H/L, while pooled SD of pore water was 0.30 mol1 $$ {}^1 $$ H/L. CONCLUSION Fast, quantitative, 2D UTE-based bound and pore water images can be acquired at arbitrary oblique orientations after correcting for errors in the slice select gradient waveform and bulk phase shift between the two half acquisitions.
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Affiliation(s)
- Kevin D Harkins
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Institute of Image Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Thammathida Ketsiri
- Institute of Image Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Jeffry S Nyman
- Institute of Image Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
- Orthopaedic Surgery and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mark D Does
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Institute of Image Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- Electrical Engineering, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Ma Y, Jang H, Jerban S, Chang EY, Chung CB, Bydder GM, Du J. Making the invisible visible-ultrashort echo time magnetic resonance imaging: Technical developments and applications. APPLIED PHYSICS REVIEWS 2022; 9:041303. [PMID: 36467869 PMCID: PMC9677812 DOI: 10.1063/5.0086459] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 09/12/2022] [Indexed: 05/25/2023]
Abstract
Magnetic resonance imaging (MRI) uses a large magnetic field and radio waves to generate images of tissues in the body. Conventional MRI techniques have been developed to image and quantify tissues and fluids with long transverse relaxation times (T2s), such as muscle, cartilage, liver, white matter, gray matter, spinal cord, and cerebrospinal fluid. However, the body also contains many tissues and tissue components such as the osteochondral junction, menisci, ligaments, tendons, bone, lung parenchyma, and myelin, which have short or ultrashort T2s. After radio frequency excitation, their transverse magnetizations typically decay to zero or near zero before the receiving mode is enabled for spatial encoding with conventional MR imaging. As a result, these tissues appear dark, and their MR properties are inaccessible. However, when ultrashort echo times (UTEs) are used, signals can be detected from these tissues before they decay to zero. This review summarizes recent technical developments in UTE MRI of tissues with short and ultrashort T2 relaxation times. A series of UTE MRI techniques for high-resolution morphological and quantitative imaging of these short-T2 tissues are discussed. Applications of UTE imaging in the musculoskeletal, nervous, respiratory, gastrointestinal, and cardiovascular systems of the body are included.
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Affiliation(s)
- Yajun Ma
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, California 92037, USA
| | | | | | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Jiang Du
- Author to whom correspondence should be addressed:. Tel.: (858) 246-2248, Fax: (858) 246-2221
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Hankiewicz JH, Celinski Z, Camley RE. Measurement of sub-zero temperatures in MRI using T 1 temperature sensitive soft silicone materials: Applications for MRI-guided cryosurgery. Med Phys 2021; 48:6844-6858. [PMID: 34562287 DOI: 10.1002/mp.15252] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/12/2021] [Accepted: 09/17/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE One standard method, proton resonance frequency shift, for measuring temperature using magnetic resonance imaging (MRI), in MRI-guided surgeries, fails completely below the freezing point of water. Because of this, we have developed a new methodology for monitoring temperature with MRI below freezing. The purpose of this paper is to show that a strong temperature dependence of the nuclear relaxation time T1 in soft silicone polymers can lead to temperature-dependent changes of MRI intensity acquired with T1 weighting. We propose the use of silicone filaments inserted in tissue for measuring temperature during MRI-guided cryoablations. METHODS The temperature dependence of T1 in bio-compatible soft silicone polymers was measured using nuclear magnetic resonance spectroscopy and MRI. Phantoms, made of bulk silicone materials and put in an MRI-compatible thermal container with dry ice, allowed temperature measurements ranging from -60°C to + 20°C. T1 -weighted gradient echo images of the phantoms were acquired at spatially uniform temperatures and with a gradient in temperature to determine the efficacy of using these materials as temperature indicators in MRI. Ex vivo experiments on silicone rods, 4 mm in diameter, inserted in animal tissue were conducted to assess the practical feasibility of the method. RESULTS Measurements of nuclear relaxation times of protons in soft silicone polymers show a monotonic, nearly linear, change with temperature (R2 > 0.98) and have a significant correlation with temperature (Pearson's r > 0.99, p < 0.01). Similarly, the intensity of the MR images in these materials, taken with a gradient echo sequence, are also temperature dependent. There is again a monotonic change in MRI intensity that correlates well with the measured temperature (Pearson's r < -0.98 and p < 0.01). The MRI experiments show that a temperature change of 3°C can be resolved in a distance of about 2.5 mm. Based on MRI images and external sensor calibrations for a sample with a gradient in temperature, temperature maps with 3°C isotherms are created for a bulk phantom. Experiments demonstrate that these changes in MRI intensity with temperature can also be seen in 4 mm silicone rods embedded in ex vivo animal tissue. CONCLUSIONS We have developed a new method for measuring temperature in MRI that potentially could be used during MRI-guided cryoablation operations, reducing both procedure time and cost, and making these surgeries safer.
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Affiliation(s)
- Janusz H Hankiewicz
- UCCS BioFrontiers Center, University of Colorado at Colorado Springs, USA.,MRX Analytics, PBC, Colorado Springs, Colorado, USA
| | - Zbigniew Celinski
- UCCS BioFrontiers Center, University of Colorado at Colorado Springs, USA.,MRX Analytics, PBC, Colorado Springs, Colorado, USA
| | - Robert E Camley
- UCCS BioFrontiers Center, University of Colorado at Colorado Springs, USA.,MRX Analytics, PBC, Colorado Springs, Colorado, USA
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Lombardi AF, Jang H, Wei Z, Jerban S, Wallace M, Masuda K, Ma YJ. High-contrast osteochondral junction imaging using a 3D dual adiabatic inversion recovery-prepared ultrashort echo time cones sequence. NMR IN BIOMEDICINE 2021; 34:e4559. [PMID: 34021649 PMCID: PMC8254801 DOI: 10.1002/nbm.4559] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/14/2021] [Accepted: 05/06/2021] [Indexed: 05/08/2023]
Abstract
While conventional MRI sequences cannot visualize tissues from the osteochondral junction (OCJ) due to these tissues' short transverse T2 /T2 * relaxations, ultrashort echo time (UTE) sequences can overcome this limitation. A 2D UTE sequence with a dual adiabatic inversion recovery preparation (DIR-UTE) for selective imaging of short T2 tissues with high contrast has previously been developed, but high sensitivity to eddy currents and aliased out-of-slice excitation make it difficult to image the thin layer of the OCJ in vivo. Here, we combine the DIR scheme with a 3D UTE cones sequence for volumetric imaging of OCJ tissues in vivo, aiming to generate higher OCJ contrast compared with a recently developed single IR-prepared UTE sequence with a fat saturation module (IR-FS-UTE). All sequences were implemented on a 3-T clinical scanner. The DIR-UTE cones sequence combined a 3D UTE cones sequence with two narrow-band adiabatic IR preparation pulses centered on water and fat spectrum frequencies, respectively. The 3D DIR-UTE cones sequence was first applied to a phantom, then to the knees of four healthy volunteers and four patients diagnosed with osteoarthritis and compared with the IR-FS-UTE sequence. In both phantom and volunteer studies, the proposed DIR-UTE cones sequence showed much higher contrast for OCJ imaging than the IR-FS-UTE sequence did. The 3D DIR-UTE cones sequence showed a significantly higher contrast-to-noise ratio between the OCJ and subchondral bone fat (mean, standard deviation [SD]: 25.7 ± 2.3) and between the OCJ and superficial layers of cartilage (mean, SD: 22.2 ± 3.5) compared with the IR-FS-UTE sequence (mean, SD: 10.8 ± 2.5 and 16.3 ± 2.6, respectively). The 3D DIR-UTE cones sequence is feasible for imaging of the OCJ region of the knee in vivo and produces both high resolution and high contrast.
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Affiliation(s)
- Alecio F. Lombardi
- Department of Radiology, University of California, San Diego, CA
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, CA
| | - Zhao Wei
- Department of Radiology, University of California, San Diego, CA
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, CA
| | - Mark Wallace
- Department of Anesthesiology, University of California San Diego, La Jolla, CA
| | - Koichi Masuda
- Department of Orthopedic Surgery, University of California San Diego, La Jolla, CA
| | - Ya-Jun Ma
- Department of Radiology, University of California, San Diego, CA
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Kim DJ, Hwang K, Kim H, Cha JG, Jang H, Park JY, Kim YJ. Depiction of the Periosteum Using Ultrashort Echo Time Pulse Sequence with Three-Dimensional Cone Trajectory and Histologic Correlation in a Porcine Model. Korean J Radiol 2021; 22:782-791. [PMID: 33660460 PMCID: PMC8076835 DOI: 10.3348/kjr.2020.0640] [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: 05/25/2020] [Revised: 08/16/2020] [Accepted: 10/14/2020] [Indexed: 12/31/2022] Open
Abstract
Objective To evaluate the signal intensity of the periosteum using ultrashort echo time pulse sequence with three-dimensional cone trajectory (3D UTE) with or without fat suppression (FS) to distinguish from artifacts in porcine tibias. Materials and Methods The periosteum and overlying soft tissue of three porcine lower legs were partially peeled away from the tibial cortex. Another porcine tibia was prepared as three segments: with an intact periosteum outer and inner layer, with an intact periosteum inner layer, and without periosteum. Axial T1 weighted sequence (T1 WI) and 3D UTE (FS) were performed. Another porcine tibia without periosteum was prepared and subjected to 3D UTE (FS) and T1 WI twice, with positional changes. Two radiologists analyzed images to reach a consensus. Results The three periosteal tissues that were partially peeled away from the cortex showed a high signal in 3D UTE (FS) and low signal on T1 WI. 3D UTE (FS) showed a high signal around the cortical surface with an intact outer and inner periosteum, and subtle high signals, mainly around the upper cortical surfaces with the inner layer of the periosteum and without periosteum. T1 WI showed no signal around the cortical surfaces, regardless of the periosteum state. The porcine tibia without periosteum showed changes in the high signal area around the cortical surface as the position changed in 3D UTE (FS). No signal was detected around the cortical surface in T1 WI, regardless of the position change. Conclusion The periosteum showed a high signal in 3D UTE and 3D UTE FS that overlapped with artifacts around the cortical bone.
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Affiliation(s)
- Dae Joong Kim
- Department of Anatomy, College of Medicine, Inha University, Incheon, Korea
| | - Kun Hwang
- Department of Plastic Surgery, College of Medicine, Inha University, Incheon, Korea
| | - Hun Kim
- Department of Plastic Surgery, College of Medicine, Inha University, Incheon, Korea
| | - Jang Gyu Cha
- Department of Radiology, Soonchunhyang University Hospital, Bucheon, Korea
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Ju Yong Park
- Department of Radiology, College of Medicine, Inha University, Incheon, Korea
| | - Yeo Ju Kim
- Department of Radiology, College of Medicine, Inha University, Incheon, Korea.
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Stumpf K, Kaye E, Paul J, Wundrak S, Pauly JM, Rasche V. Two‐dimensional UTE overview imaging for dental application. Magn Reson Med 2020; 84:2616-2624. [DOI: 10.1002/mrm.28312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/10/2020] [Accepted: 04/16/2020] [Indexed: 12/22/2022]
Affiliation(s)
- Kilian Stumpf
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
| | - Elena Kaye
- Department of Medical Physics Memorial Sloan Kettering Cancer Center New York New York USA
| | - Jan Paul
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
- Dental Imaging Dentsply Sirona Bensheim Germany
| | - Stefan Wundrak
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
- Dental Imaging Dentsply Sirona Bensheim Germany
| | - John M. Pauly
- Department of Electrical Engineering Stanford University Stanford California USA
| | - Volker Rasche
- Department of Internal Medicine II Ulm University Medical Center Ulm Germany
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Latta P, Starčuk Z, Kojan M, Gruwel MLH, Tomanek B, Trattnig S, Juras V. Simple compensation method for improved half-pulse excitation profile with rephasing gradient. Magn Reson Med 2020; 84:1796-1805. [PMID: 32129544 DOI: 10.1002/mrm.28233] [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: 11/04/2019] [Revised: 01/14/2020] [Accepted: 02/07/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE To improve the slice profile quality obtained by RF half-pulse excitation for 2D-UTE applications. METHODS The overall first-order and zero-order phase errors along the slice-selection direction were obtained with the help of an optimization task to minimize the out-of-slice signal contamination from the calibration 1-dimenisonal (1D) profile data. The time-phase-error evolution was approximated from the k-space readout data, which were acquired primarily for correction of the readout trajectories during data regridding to the rectilinear grids. The correction of the slice profile was achieved by rephasing gradient pulses applied immediately after the end of excitation. The total prescan calibration typically took less than 2 minutes. RESULTS The improved image quality using the proposed calibration method was demonstrated both on phantoms and on ankle images obtained from healthy volunteers. It was demonstrated that calibration can be performed either as a separate water phantom measurement or directly as a prescan procedure. CONCLUSION The slice-profile distortion from the half-pulse excitation could substantially affect the overall fidelity of 2D-UTE images. The presented experiments proved that the image quality could be substantially increased by application of the proposed slice-correction method.
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Affiliation(s)
- Peter Latta
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Zenon Starčuk
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Martin Kojan
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Marco L H Gruwel
- Biological Resources Imaging Laboratory, Mark Wainwright Analytical Centre, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Boguslaw Tomanek
- Department of Oncology, Division of Medical Physics, University of Alberta, Edmonton, AB, Canada
| | - Siegfried Trattnig
- High-Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Vladimir Juras
- High-Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
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Woodrum DA, Kawashima A, Gorny KR, Mynderse LA. Magnetic Resonance-Guided Prostate Ablation. Semin Intervent Radiol 2019; 36:351-366. [PMID: 31798208 PMCID: PMC6887527 DOI: 10.1055/s-0039-1697001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In 2019, the American Cancer Society (ACS) estimates that 174,650 new cases of prostate cancer will be diagnosed and 31,620 will die due to the prostate cancer in the United States. Prostate cancer is often managed with aggressive curative intent standard therapies including radiotherapy or surgery. Regardless of how expertly done, these standard therapies often bring significant risk and morbidity to the patient's quality of life with potential impact on sexual, urinary, and bowel functions. Additionally, improved screening programs, using prostatic-specific antigen and transrectal ultrasound-guided systematic biopsy, have identified increasing numbers of low-risk, low-grade "localized" prostate cancer. The potential, localized, and indolent nature of many prostate cancers presents a difficult decision of when to intervene, especially within the context of the possible comorbidities of aggressive standard treatments. Active surveillance has been increasingly instituted to balance cancer control versus treatment side effects; however, many patients are not comfortable with this option. Although active debate continues on the suitability of either focal or regional therapy for the low- or intermediate-risk prostate cancer patients, no large consensus has been achieved on the adequate management approach. Some of the largest unresolved issues are prostate cancer multifocality, limitations of current biopsy strategies, suboptimal staging by accepted imaging modalities, less than robust prediction models for indolent prostate cancers, and safety and efficiency of the established curative therapies following focal therapy for prostate cancer. In spite of these restrictions, focal therapy continues to confront the current paradigm of therapy for low- and even intermediate-risk disease. It has been proposed that early detection and proper characterization may play a role in preventing the development of metastatic disease. There is level-1 evidence supporting detection and subsequent aggressive treatment of intermediate- and high-risk prostate cancer. Therefore, accurate assessment of cancer risk (i.e., grade and stage) using imaging and targeted biopsy is critical. Advances in prostate imaging with MRI and PET are changing the workup for these patients, and advances in MR-guided biopsy and therapy are propelling prostate treatment solutions forward faster than ever.
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Lu A, Atkinson IC, Thulborn KR. Motion reduction for quantitative brain sodium MR imaging with a navigated flexible twisted projection imaging sequence at 9.4 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 307:106582. [PMID: 31499470 DOI: 10.1016/j.jmr.2019.106582] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/16/2019] [Accepted: 08/20/2019] [Indexed: 06/10/2023]
Abstract
Quantitative measurement of the tissue sodium concentration (TSC) provides a metric for tissue cell volume fraction for monitoring tumor responses to therapy and neurodegeneration in the brain as well as applications outside the central nervous system such as the fixed charge density in cartilage. Despite the low detection sensitivity of the sodium MR signal compared to the proton signal and the requirement for a long repetition time to minimize longitudinal magnetization saturation, acquisition time has been reduced to less than 10 min for a nominal isotropic voxel size of 3.3 mm with the improved acquisition efficiency of twisted projection imaging (TPI) at 9.4 T. However, patient motion can degrade the accuracy of the quantification even within these acquisition times. Our goal has been to improve the robustness of quantitative sodium MR imaging by minimizing the impact of motion that may occur even in cooperative patients. We present a method to spatially encode a lower resolution navigator echo after encoding the free induction decay signal for the quantitative image at no time penalty. Both the imaging and navigator data are sampled with flexTPI readout trajectories. Navigator images are generated at a higher temporal resolution (∼1 min) albeit at lower spatial resolution (8 mm) than the quantitative high-resolution images. The multiple volumes of navigator echo images are then aligned to extract the translational and rotational motion parameters assuming rigid-body motion. These parameters are used to align the k-space data during the acquisition of each volume of the quantitative images. Our results show significantly reduced image blurring with this method when the subject's head moved randomly by up to 7° between the navigator acquisitions.
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Affiliation(s)
- Aiming Lu
- Department of Radiology, Mayo Clinic, Rochester, MN 55901, United States.
| | - Ian C Atkinson
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Keith R Thulborn
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, IL 60612, United States
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Wan L, Wu M, Sheth V, Shao H, Jang H, Bydder G, Du J. Evaluation of cortical bone perfusion using dynamic contrast enhanced ultrashort echo time imaging: a feasibility study. Quant Imaging Med Surg 2019; 9:1383-1393. [PMID: 31559167 DOI: 10.21037/qims.2019.08.05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been used to study perfusion in a wide variety of soft tissues including the bone marrow. Study of perfusion in hard tissues such as cortical bone has been much more limited because of the lack of detectable MR signal from them using conventional pulse sequences. However, two-dimensional (2D) ultrashort echo time (UTE) sequences detect signal from cortical bone and allow fast imaging of this tissue. In addition, adiabatic 2D inversion recovery UTE (IR-UTE) sequences can provide excellent signal suppression of soft tissues, such as muscle and marrow, and allow cortical bone to be seen with high contrast and reduced artefacts. We aimed to assess the feasibility of using 2D UTE and 2D IR-UTE sequences to perform DCE-MRI in the cortical bone of rabbits and human volunteers. Methods Cortical bone perfusion was studied in rabbits (n=12) and human volunteers (n=3) using 2D UTE and 2D IR-UTE sequences on a clinical 3T scanner. Dynamic data with an in-plane resolution of ~0.5×0.5 mm2, single slice thickness of 3 mm for rabbits and 10 mm for human volunteers, and temporal resolution of 23 s for 2D UTE imaging of rabbits, 28 s for 2D UTE imaging of human volunteers, and 60 s for 2D IR-UTE imaging of both the rabbits and human volunteers were acquired before and after the injection of a Gd contrast agent (Gd-BOPTA: Multihance; Bracco Imaging SpA, Milan, Italy). The dose was 0.06 mmol/kg for rabbits and 0.2 mmol/kg for human subjects. Kinetic analyses based on the Brix model, as well as simple calculations of maximum enhancement (ME) and enhancement slope (ES), were performed. Results The 12 rabbits showed a mean Ktrans of 0.36±0.07 min-1, Kep of 8.42±3.17 min-1, ME of 28.30±6.83, ES of 0.35±0.18 for the femur with the 2D UTE sequence, and a mean Ktrans of 0.45±0.10 min-1, Kep of 9.80±0.50 min-1, ME of 48.84±12.12, and ES of 0.69±0.27 for the femur with the 2D IR-UTE sequence. Lower ME and ES values were observed in the tibial midshaft of healthy human volunteers compared to rabbits. Conclusions These results show that 2D UTE and 2D IR-UTE sequences are capable of detecting dynamic contrast enhancement in cortical bone in both rabbits and healthy human volunteers. Clinical studies with these techniques are likely to be feasible.
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Affiliation(s)
- Lidi Wan
- Department of Radiology, University of California, San Diego, CA, USA
| | - Mei Wu
- Department of Radiology, University of California, San Diego, CA, USA
| | - Vipul Sheth
- Department of Radiology, University of California, San Diego, CA, USA
| | - Hongda Shao
- Department of Radiology, University of California, San Diego, CA, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, CA, USA
| | - Graeme Bydder
- Department of Radiology, University of California, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA, USA
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Abstract
OBJECTIVE Imaging plays a key role in the assessment of patients before, during, and after percutaneous cryoablation of hepatic tumors. Intra-procedural and early post-procedure imaging with CT and MRI is vital to the assessment of technical success including adequacy of ablation zone coverage. Recognition of the normal expected post-procedure findings of hepatic cryoablation such as ice ball formation, hydrodissection, and the normal appearance of the ablation zone is crucial to be able to differentiate from complications including vascular, biliary, or non-target organ injury. Delayed imaging is essential for determination of clinical effectiveness and detection of unexpected findings such as residual unablated tumor and local tumor progression. The purpose of this article is to review the spectrum of expected and unexpected imaging findings that may occur during or after percutaneous cryoablation of hepatic tumors. CONCLUSION Differentiating expected from unexpected findings during and after hepatic cryoablation helps radiologists identify residual or recurrent tumor and detect procedure-related complications.
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12
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Ma YJ, Jerban S, Carl M, Wan L, Guo T, Jang H, Bydder GM, Chang EY, Du J. Imaging of the region of the osteochondral junction (OCJ) using a 3D adiabatic inversion recovery prepared ultrashort echo time cones (3D IR-UTE-cones) sequence at 3 T. NMR IN BIOMEDICINE 2019; 32:e4080. [PMID: 30794338 PMCID: PMC7895481 DOI: 10.1002/nbm.4080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/16/2019] [Accepted: 01/18/2019] [Indexed: 05/18/2023]
Abstract
The purpose of this study is to develop a 3D adiabatic inversion recovery prepared ultrashort echo time Cones (3D IR-UTE-Cones) sequence for high resolution and contrast imaging of the region of osteochondral junction (OCJ) of human knee joint using a clinical 3 T scanner. A feasibility study on direct imaging of the OCJ region was performed on a human patellar cartilage sample and on eight cadaveric knee joints using T1 -weighted, proton density (PD)-weighted and short-T2 -weighted 3D IR-UTE-Cones sequences. Contrast to noise ratio was measured to evaluate the effectiveness of the 3D IR-UTE-Cones sequences for selective imaging of the OCJ region. Computed tomography imaging was performed in parallel for the cadaveric knee joints. The optimized T1 -weighted 3D IR-UTE-Cones sequence was used to image the knee joints of eight healthy volunteers and six patients with osteoarthritis (OA) to evaluate morphological changes in the OCJ region. Clinical PD- and T2 -weighted FSE sequences were also performed for comparison. The T1 -weighted 3D IR-UTE-Cones sequence showed high resolution and contrast bright band of the normal OCJ region in the cadaveric joints. Normal OCJ appearances were also seen in healthy volunteers. Abnormal OCJ regions, manifested as ill-defined, focal loss or non-visualization of the high intensity band adjacent to the subchondral bone plate, were observed in the knee joints of both ex vivo and in vivo OA patients. The 3D IR-UTE-Cones sequence can image OCJ regions ex vivo and in vivo, with abnormalities depicted with high resolution and contrast. The technique may be useful for demonstrating involvement of OCJ regions in early OA.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California, San Diego, CA
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, CA
| | | | - Lidi Wan
- Department of Radiology, University of California, San Diego, CA
| | - Tan Guo
- Department of Radiology, University of California, San Diego, CA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, CA
| | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, CA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA
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Armstrong T, Liu D, Martin T, Masamed R, Janzen C, Wong C, Chanlaw T, Devaskar SU, Sung K, Wu HH. 3D R 2 * mapping of the placenta during early gestation using free-breathing multiecho stack-of-radial MRI at 3T. J Magn Reson Imaging 2018; 49:291-303. [PMID: 30142239 DOI: 10.1002/jmri.26203] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/08/2018] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Multiecho gradient-echo Cartesian MRI characterizes placental oxygenation by quantifying R 2 * . Previous research was performed at 1.5T using breath-held 2D imaging during later gestational age (GA). PURPOSE To evaluate the accuracy and repeatability of a free-breathing (FB) 3D multiecho gradient-echo stack-of-radial technique (radial) for placental R 2 * mapping at 3T and report placental R 2 * during early GA. STUDY TYPE Prospective. POPULATION Thirty subjects with normal pregnancies and three subjects with ischemic placental disease (IPD) were scanned twice: between 14-18 and 19-23 weeks GA. FIELD STRENGTH 3T. SEQUENCE FB radial. ASSESSMENT Linear correlation (concordance coefficient, ρc ) and Bland-Altman analyses (mean difference, MD) were performed to evaluate radial R 2 * mapping accuracy compared to Cartesian in a phantom. Radial R 2 * mapping repeatability was characterized using the coefficient of repeatability (CR) between back-to-back scans. The mean and spatial coefficient of variation (CV) of R 2 * was determined for all subjects, and separately for anterior and posterior placentas, at each GA range. STATISTICAL TESTS ρc was tested for significance. Differences in mean R 2 * and CV were tested using Wilcoxon Signed-Rank and Rank-Sum tests. P < 0.05 was considered significant. Z-scores for the IPD subjects were determined. RESULTS FB radial demonstrated accurate (ρc ≥0.996; P < 0.001; |MD|<0.2s-1 ) and repeatable (CR<4s-1 ) R 2 * mapping in a phantom, and repeatable (CR≤4.6s-1 ) R 2 * mapping in normal subjects. At 3T, placental R 2 * mean ± standard deviation was 12.9s-1 ± 2.7s-1 for 14-18 and 13.2s-1 ± 1.9s-1 for 19-23 weeks GA. The CV was significantly greater (P = 0.043) at 14-18 (0.63 ± 0.12) than 19-23 (0.58 ± 0.13) weeks GA. At 19-23 weeks, the CV was significantly lower (P < 0.001) for anterior (0.49 ± 0.08) than posterior (0.67 ± 0.11) placentas. One IPD subject had a lower mean R 2 * than normal subjects at both GA ranges (Z<-2). DATA CONCLUSION FB radial provides accurate and repeatable 3D R 2 * mapping for the entire placenta at 3T during early GA. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:291-303.
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Affiliation(s)
- Tess Armstrong
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA.,Department of Physics and Biology in Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Dapeng Liu
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA
| | - Thomas Martin
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA.,Department of Physics and Biology in Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Rinat Masamed
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA
| | - Carla Janzen
- Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Cass Wong
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA
| | - Teresa Chanlaw
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Sherin U Devaskar
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Kyunghyun Sung
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA.,Department of Physics and Biology in Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Holden H Wu
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, USA.,Department of Physics and Biology in Medicine, University of California Los Angeles, Los Angeles, California, USA
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14
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Fan SJ, Ma Y, Zhu Y, Searleman A, Szeverenyi NM, Bydder GM, Du J. Yet more evidence that myelin protons can be directly imaged with UTE sequences on a clinical 3T scanner: Bicomponent T2* analysis of native and deuterated ovine brain specimens. Magn Reson Med 2018; 80:538-547. [PMID: 29271083 PMCID: PMC5910230 DOI: 10.1002/mrm.27052] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/05/2017] [Accepted: 11/29/2017] [Indexed: 01/15/2023]
Abstract
PURPOSE UTE sequences with a minimal nominal TE of 8 µs have shown promise for direct imaging of myelin protons (T2 , < 1 ms). However, there is still debate about the efficiency of 2D slice-selective UTE sequences in exciting myelin protons because the half excitation pulses used in these sequences have a relatively long duration (e.g., 0.3-0.6 ms). Here, we compared UTE and inversion-recovery (IR) UTE sequences used with either hard or half excitation pulses (durations 32 µs or 472 µs, respectively) for imaging myelin in native and deuterated ovine brain at 3T. METHODS Freshly frozen ovine brains were dissected into ∼2 mm-thick pure white matter and ∼3 to 8 mm-thick cerebral hemisphere specimens, which were imaged before and/or after different immersion time in deuterium oxide. RESULTS Bicomponent T2* analysis of UTE signals obtained with hard excitation pulses detected an ultrashort T2 component (STC) fraction (fS ) of 0% to 10% in native specimens, and up to ∼86% in heavily deuterated specimens. fS values were significantly affected by the TIs used in IR-UTE sequences with either hard or half excitation pulses in native specimens but not in heavily deuterated specimens. The STC T2* was in the range of 150 to 400 µs in all UTE and IR-UTE measurements obtained with either hard or half excitation pulses. CONCLUSION Our results further support myelin protons as the major source of the ultrashort T2* signals seen on IR-UTE images and demonstrate the potential of IR-UTE sequences with half excitation pulses for directly imaging myelin using clinical scanners. Magn Reson Med 80:538-547, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Shu-Juan Fan
- Department of Radiology, University of California, San Diego
| | - Yajun Ma
- Department of Radiology, University of California, San Diego
| | - Yanchun Zhu
- Department of Radiology, University of California, San Diego
| | - Adam Searleman
- Department of Radiology, University of California, San Diego
| | | | | | - Jiang Du
- Department of Radiology, University of California, San Diego
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15
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Chen B, Zhao Y, Cheng X, Ma Y, Chang EY, Kavanaugh A, Liu S, Du J. Three-dimensional ultrashort echo time cones (3D UTE-Cones) magnetic resonance imaging of entheses and tendons. Magn Reson Imaging 2018; 49:4-9. [DOI: 10.1016/j.mri.2017.12.034] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 12/29/2017] [Indexed: 11/15/2022]
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16
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Abstract
Prostate cancer is the most commonly diagnosed noncutaneous cancer and second leading cause of death in men. Many patients with clinically organ-confined prostate cancer undergo definitive treatment of the whole gland, including radical prostatectomy, radiation therapy, and cryosurgery. Active surveillance is a growing alternative option for patients with documented low-volume and low-grade prostate cancer. However, many patients are wanting a less morbid focal treatment alternative. With recent advances in software and hardware of magnetic resonance imaging (MRI), multiparametric MRI of the prostate has been shown to improve the accuracy in detecting and characterizing clinically significant prostate cancer. Targeted biopsy is increasingly utilized to improve the yield of MR detected, clinically significant prostate cancer and to decrease in detection of indolent prostate cancer. MR-guided targeted biopsy techniques include cognitive MR fusion transrectal ultrasound (TRUS) biopsy, in-bore transrectal targeted biopsy using robotic transrectal device, and in-bore direct MR-guided transperineal biopsy with a software based transperineal grid template. In addition, advances in MR-compatible thermal ablation technology allow accurate focal or regional delivery of thermal ablative energy to the biopsy-proved, MRI-detected tumor. MR-guided ablative treatment options include cryoablation, laser ablation, and high-intensity focused ultrasound with real-time or near simultaneous monitoring of the ablation zone. We present a contemporary review of MR-guided techniques for prostatic interventions.
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Latta P, Starčuk Z, Gruwel MLH, Lattova B, Lattova P, Štourač P, Tomanek B. Influence of k-space trajectory corrections on proton density mapping with ultrashort echo time imaging: Application for imaging of short T2 components in white matter. Magn Reson Imaging 2018; 51:87-95. [PMID: 29729437 DOI: 10.1016/j.mri.2018.04.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/30/2018] [Accepted: 04/30/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE To evaluate the impact of MR gradient system imperfections and limitations for the quantitative mapping of short T2* signals performed by ultrashort echo time (UTE) acquisition approach. MATERIALS AND METHODS The measurement of short T2* signals from a phantom and a healthy volunteer study (8 subjects of average age 28 ± 4 years) were performed on a 3T scanner. The characteristics of the gradient system were obtained using calibration method performed directly on the measured subject or phantom. This information was used to calculate the actual sampling trajectory with the help of a parametric eddy current model. The actual sample positions were used to reconstruct corrected images and compared with uncorrected data. RESULTS Comparison of both approaches, i.e., without and with correction of k-space sampling trajectories revealed substantial improvement when correction was applied. The phantom experiments demonstrate substantial in-plane signal intensity variations for uncorrected sampling trajectories. In the case of the volunteer study, this led to significant differences in relative proton density (RPD) estimation between the uncorrected and corrected data (P = 0.0117 by Wilcoxon matched-pairs test) and provides for about ~15% higher values for short T2* components of white matter (WM) in the case of uncorrected images. CONCLUSION The imperfection of the applied gradients could induce errors in k-space data sampling which further propagates into the fidelity of the UTE images and jeopardizes precision of quantification. However, the study proved that measurement of gradient errors together with correction of sample positions can contribute to increased accuracy and unbiased characterization of short T2* signals.
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Affiliation(s)
- Peter Latta
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic.
| | - Zenon Starčuk
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Marco L H Gruwel
- Biological Resources Imaging Laboratory, Mark Wainwright Analytical Centre, Level 4, Lowy Cancer Research Centre, UNSW Australia, Sydney, NSW 2052, Australia
| | - Barbora Lattova
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Petra Lattova
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Pavel Štourač
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Department of Neurology, University Hospital Brno, Jihlavska 20, 62500 Brno, Czech Republic
| | - Boguslaw Tomanek
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; University of Alberta, Department of Oncology, Division of Medical Physics, 8303 - 112 Street NW, Edmonton, AB T6G 2T4, Canada
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18
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Woodrum D, Kawashima A, Gorny K, Mynderse L. Prostate cancer: state of the art imaging and focal treatment. Clin Radiol 2017; 72:665-679. [DOI: 10.1016/j.crad.2017.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/26/2017] [Accepted: 02/07/2017] [Indexed: 10/19/2022]
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19
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Ma YJ, Carl M, Shao H, Tadros AS, Chang EY, Du J. Three-dimensional ultrashort echo time cones T 1ρ (3D UTE-cones-T 1ρ ) imaging. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3709. [PMID: 28318066 PMCID: PMC5505275 DOI: 10.1002/nbm.3709] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/19/2017] [Accepted: 01/21/2017] [Indexed: 05/18/2023]
Abstract
We report a novel three-dimensional (3D) ultrashort echo time (UTE) sequence employing Cones trajectory and T1ρ preparation (UTE-Cones-T1ρ ) for quantitative T1ρ assessment of short T2 tissues in the musculoskeletal system. A basic 3D UTE-Cones sequence was combined with a spin-locking preparation pulse for T1ρ contrast. A relatively short TR was used to decrease the scan time, which required T1 measurement and compensation using 3D UTE-Cones data acquisitions with variable TRs. Another strategy to reduce the total scan time was to acquire multiple Cones spokes (Nsp ) after each T1ρ preparation and fat saturation. Four spin-locking times (TSL = 0-20 ms) were acquired over 12 min, plus another 7 min for T1 measurement. The 3D UTE-Cones-T1ρ sequence was compared with a two-dimensional (2D) spiral-T1ρ sequence for the imaging of a spherical CuSO4 phantom and ex vivo meniscus and tendon specimens, as well as the knee and ankle joints of healthy volunteers, using a clinical 3-T scanner. The CuSO4 phantom showed a T1ρ value of 76.5 ± 1.6 ms with the 2D spiral-T1ρ sequence, as well as 85.7 ± 3.6 and 89.2 ± 1.4 ms for the 3D UTE-Cones-T1ρ sequences with Nsp of 1 and 5, respectively. The 3D UTE-Cones-T1ρ sequence provided shorter T1ρ values for the bovine meniscus sample relative to the 2D spiral-T1ρ sequence (10-12 ms versus 16 ms, respectively). The cadaveric human Achilles tendon sample could only be imaged with the 3D UTE-Cones-T1ρ sequence (T1ρ = 4.0 ± 0.9 ms), with the 2D spiral-T1ρ sequence demonstrating near-zero signal intensity. Human studies yielded T1ρ values of 36.1 ± 2.9, 18.3 ± 3.9 and 3.1 ± 0.4 ms for articular cartilage, meniscus and the Achilles tendon, respectively. The 3D UTE-Cones-T1ρ sequence allows volumetric T1ρ measurement of short T2 tissues in vivo.
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Affiliation(s)
- Ya-jun Ma
- Department of Radiology, University of California, San Diego, San Diego, CA
| | | | - Hongda Shao
- Department of Radiology, University of California, San Diego, San Diego, CA
- Department of Radiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Anthony S. Tadros
- Department of Radiology, University of California, San Diego, San Diego, CA
| | - Eric Y. Chang
- Department of Radiology, University of California, San Diego, San Diego, CA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, CA
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20
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Krafft AJ, Loeffler RB, Song R, Tipirneni-Sajja A, McCarville MB, Robson MD, Hankins JS, Hillenbrand CM. Quantitative ultrashort echo time imaging for assessment of massive iron overload at 1.5 and 3 Tesla. Magn Reson Med 2017; 78:1839-1851. [PMID: 28090666 DOI: 10.1002/mrm.26592] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 01/12/2023]
Abstract
PURPOSE Hepatic iron content (HIC) quantification via transverse relaxation rate (R2*)-MRI using multi-gradient echo (mGRE) imaging is compromised toward high HIC or at higher fields due to the rapid signal decay. Our study aims at presenting an optimized 2D ultrashort echo time (UTE) sequence for R2* quantification to overcome these limitations. METHODS Two-dimensional UTE imaging was realized via half-pulse excitation and radial center-out sampling. The sequence includes chemically selective saturation pulses to reduce streaking artifacts from subcutaneous fat, and spatial saturation (sSAT) bands to suppress out-of-slice signals. The sequence employs interleaved multi-echo readout trains to achieve dense temporal sampling of rapid signal decays. Evaluation was done at 1.5 Tesla (T) and 3T in phantoms, and clinical applicability was demonstrated in five patients with biopsy-confirmed massively high HIC levels (>25 mg Fe/g dry weight liver tissue). RESULTS In phantoms, the sSAT pulses were found to remove out-of-slice contamination, and R2* results were in excellent agreement to reference mGRE R2* results (slope of linear regression: 1.02/1.00 for 1.5/3T). UTE-based R2* quantification in patients with massive iron overload proved successful at both field strengths and was consistent with biopsy HIC values. CONCLUSION The UTE sequence provides a means to measure R2* in patients with massive iron overload, both at 1.5T and 3T. Magn Reson Med 78:1839-1851, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Axel J Krafft
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.,Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ralf B Loeffler
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Ruitian Song
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Aaryani Tipirneni-Sajja
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - M Beth McCarville
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Matthew D Robson
- OCMR, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jane S Hankins
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Claudia M Hillenbrand
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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21
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Sheth VR, Fan S, He Q, Ma Y, Annese J, Switzer R, Corey-Bloom J, Bydder GM, Du J. Inversion recovery ultrashort echo time magnetic resonance imaging: A method for simultaneous direct detection of myelin and high signal demonstration of iron deposition in the brain - A feasibility study. Magn Reson Imaging 2016; 38:87-94. [PMID: 28038965 DOI: 10.1016/j.mri.2016.12.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 12/20/2016] [Accepted: 12/22/2016] [Indexed: 01/05/2023]
Abstract
Multiple sclerosis (MS) causes demyelinating lesions in the white matter and increased iron deposition in the subcortical gray matter. Myelin protons have an extremely short T2* (<1ms) and are not directly detected with conventional clinical magnetic resonance (MR) imaging sequences. Iron deposition also reduces T2*, leading to reduced signal on clinical sequences. In this study we tested the hypothesis that the inversion recovery ultrashort echo time (IR-UTE) pulse sequence can directly and simultaneously image myelin and iron deposition using a clinical 3T scanner. The technique was first validated on a synthetic myelin phantom (myelin powder in D2O) and a Feridex iron phantom. This was followed by studies of cadaveric MS specimens, healthy volunteers and MS patients. UTE imaging of the synthetic myelin phantom showed an excellent bi-component signal decay with two populations of protons, one with a T2* of 1.2ms (residual water protons) and the other with a T2* of 290μs (myelin protons). IR-UTE imaging shows sensitivity to a wide range of iron concentrations from 0.5 to ~30mM. The IR-UTE signal from white matter of the brain of healthy volunteers shows a rapid signal decay with a short T2* of ~300μs, consistent with the T2* values of myelin protons in the synthetic myelin phantom. IR-UTE imaging in MS brain specimens and patients showed multiple white matter lesions as well as areas of high signal in subcortical gray matter. This in specimens corresponded in position to Perl's diaminobenzide staining results, consistent with increased iron deposition. IR-UTE imaging simultaneously detects lesions with myelin loss in the white matter and iron deposition in the gray matter.
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Affiliation(s)
- Vipul R Sheth
- Department of Radiology, University of California, San Diego, CA, United States
| | - Shujuan Fan
- Department of Radiology, University of California, San Diego, CA, United States
| | - Qun He
- Department of Radiology, University of California, San Diego, CA, United States
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, CA, United States
| | - Jacopo Annese
- The Institute for Brain and Society, San Diego, CA, United States
| | - Robert Switzer
- NeuroScience Associates, Inc., Knoxville, TN, United States
| | - Jody Corey-Bloom
- Department of NeuroSciences, University of California, San Diego, United States
| | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, CA, United States
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA, United States.
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22
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Hong W, He Q, Fan S, Carl M, Shao H, Chen J, Chang EY, Du J. Imaging and quantification of iron-oxide nanoparticles (IONP) using MP-RAGE and UTE based sequences. Magn Reson Med 2016; 78:226-232. [PMID: 27495266 DOI: 10.1002/mrm.26371] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/16/2016] [Accepted: 07/15/2016] [Indexed: 12/11/2022]
Abstract
PURPOSE To investigate two-dimensional (2D) and three-dimensional (3D) ultrashort echo time (UTE) and 3D magnetization-prepared rapid gradient-echo (MP-RAGE) sequences for the imaging of iron-oxide nanoparticles (IONP). METHODS The phantoms were composed of tubes filled with different IONP concentrations ranging from 2 to 45 mM. The tubes were fixed in an agarose gel phantom (0.9% by weight). Morphological imaging was performed with 3D MP-RAGE, 2D UTE, 2D adiabatic inversion recovery-prepared UTE (2D IR-UTE), 3D UTE with Cones trajectory (3D Cones), and 3D IR-Cones sequences. Quantitative assessment of IONP concentration was performed using R2*(1/T2*) and R1 (1/T1 ) measurements using a 3 Tesla (T) scanner. RESULTS The 3D MP-RAGE sequence provides high-contrast images of IONP with concentration up to 7.5 mM. Higher IONP concentration up to 37.5 mM can be detected with the UTE sequences, with the highest IONP contrast provided by the 3D IR-Cones sequence. A linear relationship was observed between R2* and IONP concentration up to ∼45 mM, and between R1 and IONP concentration up to ∼30 mM. CONCLUSION The clinical 3D MP-RAGE sequence can be used to assess lower IONP concentration up to 7.5 mM. The UTE sequences can be used to assess higher IONP concentration up to 45 mM. Magn Reson Med 78:226-232, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Wen Hong
- Department of Radiology, University of California, San Diego, California, USA.,Department of Radiology, China-Japan Friendship Hospital, Beijing, China
| | - Qun He
- Department of Radiology, University of California, San Diego, California, USA.,Ningbo Jansen NMR Technology Co., Ltd, Cixi, Zhejiang Province, China
| | - Shujuan Fan
- Department of Radiology, University of California, San Diego, California, USA
| | - Michael Carl
- Applied Science Lab, GE Healthcare, San Diego, California, USA
| | - Hongda Shao
- Department of Radiology, University of California, San Diego, California, USA
| | - Jun Chen
- Department of Radiology, University of California, San Diego, California, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, California, USA.,Radiology Service, VA San Diego Healthcare System, San Diego, California, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, California, USA
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Du J, Sheth V, He Q, Carl M, Chen J, Corey-Bloom J, Bydder GM. Measurement of T1 of the ultrashort T2* components in white matter of the brain at 3T. PLoS One 2014; 9:e103296. [PMID: 25093859 PMCID: PMC4122467 DOI: 10.1371/journal.pone.0103296] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 06/27/2014] [Indexed: 11/18/2022] Open
Abstract
Recent research demonstrates that white matter of the brain contains not only long T2 components, but a minority of ultrashort T2* components. Adiabatic inversion recovery prepared dual echo ultrashort echo time (IR-dUTE) sequences can be used to selectively image the ultrashort T2* components in white matter of the brain using a clinical whole body scanner. The T2*s of the ultrashort T2* components can be quantified using mono-exponential decay fitting of the IR-dUTE signal at a series of different TEs. However, accurate T1 measurement of the ultrashort T2* components is technically challenging. Efficient suppression of the signal from the majority of long T2 components is essential for robust T1 measurement. In this paper we describe a novel approach to this problem based on the use of IR-dUTE data acquisitions with different TR and TI combinations to selectively detect the signal recovery of the ultrashort T2* components. Exponential recovery curve fitting provides efficient T1 estimation, with minimized contamination from the majority of long T2 components. A rubber phantom and a piece of bovine cortical bone were used for validation of this approach. Six healthy volunteers were studied. An averaged T2* of 0.32±0.09 ms, and a short mean T1 of 226±46 ms were demonstrated for the healthy volunteers at 3T.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California San Diego, San Diego, California, United States of America
- * E-mail:
| | - Vipul Sheth
- Department of Radiology, University of California San Diego, San Diego, California, United States of America
| | - Qun He
- Department of Radiology, University of California San Diego, San Diego, California, United States of America
| | - Michael Carl
- Global Applied Science Laboratory, GE Healthcare, San Diego, California, United States of America
| | - Jun Chen
- Department of Radiology, University of California San Diego, San Diego, California, United States of America
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - Graeme M. Bydder
- Department of Radiology, University of California San Diego, San Diego, California, United States of America
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Harkins KD, Does MD, Grissom WA. Iterative method for predistortion of MRI gradient waveforms. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:1641-7. [PMID: 24801945 PMCID: PMC4128553 DOI: 10.1109/tmi.2014.2320987] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The purpose of this work is to correct for transient gradient waveform errors in magnetic resonance imaging (MRI), whether from eddy currents, group delay, or gradient amplifier nonlinearities, which are known to affect image quality. An iterative method is proposed to minimize error between desired and measured gradient waveforms, whose success does not depend on accurate knowledge of the gradient system impulse response. The method was applied to half-pulse excitation for 2-D ultra-short echo time (UTE) imaging on a small animal MRI system and to spiral 2-D excitation on a human 7T MRI system. Predistorted gradient waveforms reduced temporal signal variation caused by excitation gradient trajectory errors in 2-D UTE, and improved the quality of excitation patterns produced by spiral excitation pulses. Iterative gradient predistortion is useful for minimizing transient gradient errors without requiring accurate characterization of the gradient system impulse response.
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25
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Chang EY, Du J, Chung CB. UTE imaging in the musculoskeletal system. J Magn Reson Imaging 2014; 41:870-83. [PMID: 25045018 DOI: 10.1002/jmri.24713] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/08/2014] [Accepted: 07/03/2014] [Indexed: 12/12/2022] Open
Abstract
Tissues, such as bone, tendon, and ligaments, contain a high fraction of components with "short" and "ultrashort" transverse relaxation times and therefore have short mean transverse relaxation times. With conventional magnetic resonance imaging (MRI) sequences that employ relatively long echo times (TEs), there is no opportunity to encode the decaying signal of short and ultrashort T2 /T2 * tissues before it has reached zero or near zero. The clinically compatible ultrashort TE (UTE) sequence has been increasingly used to study the musculoskeletal system. This article reviews the UTE sequence as well as various modifications that have been implemented since its introduction. These modifications have been used to improve efficiency or contrast as well as provide quantitative analysis. This article reviews several clinical musculoskeletal applications of UTE.
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Affiliation(s)
- Eric Y Chang
- Department of Radiology, VA San Diego Healthcare System, San Diego, California, USA; Department of Radiology, University of California, San Diego Medical Center, San Diego, California, USA
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Harkins KD, Horch RA, Does MD. Simple and robust saturation-based slice selection for ultrashort echo time MRI. Magn Reson Med 2014; 73:2204-11. [PMID: 25046136 DOI: 10.1002/mrm.25361] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/06/2014] [Accepted: 06/21/2014] [Indexed: 12/23/2022]
Abstract
PURPOSE To present a new method for localizing signal within a two-dimensional (2D) slice suitable for ultrashort echo time (UTE) imaging, called saturation-based UTE (sat-UTE). The new method digitally subtracts two acquisitions that are nonselectively excited with and without selective saturation of the slice of interest. METHODS Sat-UTE was compared with half-pulse and double-half pulse excited UTE within phantoms, as well as 3D-UTE within ex vivo femur and in vivo tibia. Numerical simulations were also used to quantify the effects of slice profile broadening and signal component amplitudes for quantitative UTE. RESULTS Sat-UTE is robust to suppress out-of-slice signal, and produces short T2 signal decay curves comparable to 3D-UTE, but has a lower signal to noise ratio efficiency compared with other slice-selective methods. CONCLUSION The proposed method is useful for fast, quantitative evaluation of short T2 signals, and is insensitive to gradient performance.
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Affiliation(s)
- Kevin D Harkins
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | - R Adam Horch
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Mark D Does
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Electrical Engineering, Vanderbilt University, Nashville, Tennessee, USA
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Du J, Ma G, Li S, Carl M, Szeverenyi NM, VandenBerg S, Corey-Bloom J, Bydder GM. Ultrashort echo time (UTE) magnetic resonance imaging of the short T2 components in white matter of the brain using a clinical 3T scanner. Neuroimage 2013; 87:32-41. [PMID: 24188809 DOI: 10.1016/j.neuroimage.2013.10.053] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/01/2013] [Accepted: 10/24/2013] [Indexed: 11/19/2022] Open
Abstract
White matter of the brain contains a majority of long T2 components as well as a minority of short T2 components. These are not detectable using clinical magnetic resonance imaging (MRI) sequences with conventional echo times (TEs). In this study we used ultrashort echo time (UTE) sequences to investigate the ultrashort T2 components in white matter of the brain and quantify their T2*s and relative proton densities (RPDs) (relative to water with a proton density of 100%) using a clinical whole body 3T scanner. An adiabatic inversion recovery prepared dual echo UTE (IR-dUTE) sequence was used for morphological imaging of the ultrashort T2 components in white matter. IR-dUTE acquisitions at a constant TR of 1000 ms and a series of TIs were performed to determine the optimal TI which corresponded to the minimum signal to noise ratio (SNR) in white matter of the brain on the second echo image. T2*s of the ultrashort T2 components were quantified using mono-exponential decay fitting of the IR-dUTE signal at a series of TEs. RPD was quantified by comparing IR-dUTE signal of the ultrashort T2 components with that of a rubber phantom. Nine healthy volunteers were studied. The IR-dUTE sequence provided excellent image contrast for the ultrashort T2 components in white matter of the brain with a mean signal to noise ratio of 18.7 ± 3.7 and a contrast to noise ratio of 14.6 ± 2.4 between the ultrashort T2 white matter and gray matter in a 4.4 min scan time with a nominal voxel size of 1.25 × 1.25 × 5.0mm(3). On average a T2* value of 0.42 ± 0.08 ms and a RPD of 4.05 ± 0.88% were demonstrated for the ultrashort T2 components in white matter of the brain of healthy volunteers at 3T.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, USA.
| | - Guolin Ma
- Department of Radiology, University of California, San Diego, USA; Department of Radiology, China-Japan Friendship Hospital, Beijing, China
| | - Shihong Li
- Department of Radiology, University of California, San Diego, USA; Department of Radiology, Huadong Hospital, Fudan University, Shanghai, China
| | - Michael Carl
- Global Applied Science Laboratory, GE Healthcare, San Diego, USA
| | | | - Scott VandenBerg
- Department of Pathology, University of California, San Diego, USA
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California, San Diego, USA
| | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, USA
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Abe T. Half radiofrequency pulse excitation with a dedicated prescan to correct eddy current effect and gradient delay. Med Phys 2013; 40:032304. [PMID: 23464336 DOI: 10.1118/1.4792672] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To improve the slice profile of the half radiofrequency (RF) pulse excitation and image quality of ultrashort echo time (UTE) imaging by compensating for an eddy current effect. METHODS The dedicated prescan has been developed to measure the phase accumulation due to eddy currents induced by the slice-selective gradient. The prescan measures two one-dimensional excitation k-space profiles, which can be acquired with a readout gradient in the slice-selection direction by changing the polarity of the slice-selective gradient. The time shifts due to the phase accumulation in the excitation k-space were calculated. The time shift compensated for the start time of the slice-selective gradient. The total prescan time was 6-15 s. The slice profile and the UTE image with the half RF pulse excitation were acquired to evaluate the slice selectivity and the image quality. RESULTS Improved slice selectivity was obtained. The simple method proposed in this paper can eliminate eddy current effect. Good UTE images were obtained. CONCLUSIONS The slice profile of the half RF pulse excitation and the image quality of UTE images have been improved by using a dedicated prescan. This method has a possibility that can improve the image quality of a clinical UTE imaging.
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Affiliation(s)
- Takayuki Abe
- Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan.
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Du J, Bydder GM. Qualitative and quantitative ultrashort-TE MRI of cortical bone. NMR IN BIOMEDICINE 2013; 26:489-506. [PMID: 23280581 PMCID: PMC4206448 DOI: 10.1002/nbm.2906] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 10/19/2012] [Accepted: 11/18/2012] [Indexed: 05/08/2023]
Abstract
Osteoporosis causes over 1.5 million fractures per year, costing about $15 billion annually in the USA. Current guidelines utilize bone mineral density (BMD) to assess fracture risk; however, BMD alone only accounts for 30-50% of fractures. The other two major components of bone, organic matrix and water, contribute significantly to bone mechanical properties, but cannot be assessed with conventional imaging techniques in spite of the fact that they make up about 57% of cortical bone by volume. Conventional clinical MRI usually detects signals from water in tissues without difficulty, but cannot detect the water bound to the organic matrix, or the free water in the microscopic pores of the Haversian and the lacunar-canalicular system of cortical bone, because of their very short apparent transverse relaxation times (T2 *). In recent years, a new class of sequences, ultrashort-TE (UTE) sequences, with nominal TEs of less than 100 µs, which are much shorter than the TEs available with conventional sequences, have received increasing interest. These sequences can detect water signals from within cortical bone and provide an opportunity to study disease of this tissue in a new way. This review summarizes the recent developments in qualitative UTE imaging (techniques and contrast mechanisms to produce bone images with high contrast) and quantitative UTE imaging (techniques to quantify the MR properties, including T1 , T2 * and the magnetization transfer ratio, and tissue properties, including bone perfusion, as well as total, bound and free water content) of cortical bone in vitro and in vivo. The limitations of the current techniques for clinical applications and future directions are also discussed.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, CA 92103-8226, USA.
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Kusmia S, Eliav U, Navon G, Guillot G. DQF-MT MRI of connective tissues: application to tendon and muscle. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2012; 26:203-14. [PMID: 23001199 DOI: 10.1007/s10334-012-0346-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 08/07/2012] [Accepted: 09/04/2012] [Indexed: 12/21/2022]
Abstract
OBJECT The sequence combining DQF (double quantum filtering) with magnetisation transfer (DQF-MT) was tested as an alternative to the DQF sequence for characterising tendon and muscle by MR imaging. MATERIALS AND METHODS DQF-MT images of tendon-muscle phantoms were obtained at 4.7 T using ultra-short time to echo (UTE) methods in order to alleviate the loss of SNR due to the short T2 of the tissues. Two different sampling schemes of the k-space, Cartesian or radial, were employed. In vivo images of the human ankle on a clinical 1.5 T scanner are also presented. Parameters providing optimal tendon signal as well as optimal contrast between this tissue and muscle were determined. RESULTS Two sets of parameters resulting in different contrasts between the tissues were found. For the first set (short creation time τ = 10 μs and magnetisation exchange time t LM = 100 ms), DQF-MT signals in muscle and tendon were detected, with that of the tendon being the larger one. For the second set (long creation time τ = 750 μs and magnetisation exchange time 10 μs < t LM < 100 ms), the DQF-MT signal was detected only in the tendon, and the decay of the double quantum coherence was slower than that observed for the first one, which allowed us to acquire DQF-MT MR images on a clinical 1.5 T MR scanner with minimal software interventions. In favourable conditions, the DQF-MT signal in the tendon could represent up to 10 % of the single-quantum signal. CONCLUSION Dipolar interaction within macromolecules such as collagen and myosin is at the origin of the DQF-MT signal observed in the first parameter set. This should enable the detection of muscle fibrosis.
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Affiliation(s)
- Slawomir Kusmia
- IR4M UMR8081 CNRS Univ Paris-Sud, CIERM-Hôp Bicetre, 94275, Le Kremlin Bicetre, France
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Du J, Hermida JC, Diaz E, Corbeil J, Znamirowski R, D'Lima DD, Bydder GM. Assessment of cortical bone with clinical and ultrashort echo time sequences. Magn Reson Med 2012; 70:697-704. [PMID: 23001864 DOI: 10.1002/mrm.24497] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 08/20/2012] [Accepted: 08/21/2012] [Indexed: 12/22/2022]
Abstract
We describe the use of ultrashort echo time (UTE) sequences and fast spin echo sequences to assess cortical bone using a clinical 3T scanner. Regular two- and three-dimensional UTE sequences were used to image both bound and free water in cortical bone. Adiabatic inversion recovery prepared UTE sequences were used to image water bound to the organic matrix. Two-dimensional fast spin echo sequences were used to image free water. Regular UTE sequences were used together with bicomponent analysis to measure T*2s and relative fractions of bound and free water components in cortical bone. Inversion recovery prepared UTE sequences were used to measure the T*2 of bound water. Saturation recovery UTE sequences were used to measure the T1 of bone water. Eight cadaveric human cortical bone samples and a lower leg specimen were studied. Preliminary results show two distinct components in UTE detected signal decay, a single component in inversion recovery prepared UTE detected signal decay, and a single component in saturation recovery UTE detected signal recovery. Regular UTE sequences appear to depict both bound and free water in cortical bone. Inversion recovery prepared UTE sequences appear to depict water bound to the organic matrix. Two-dimensional fast spin echo sequences appear to depict bone structure corresponding to free water in large pores.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, California, USA
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Pauli C, Bae WC, Lee M, Lotz M, Bydder GM, D'Lima DL, Chung CB, Du J. Ultrashort-echo time MR imaging of the patella with bicomponent analysis: correlation with histopathologic and polarized light microscopic findings. Radiology 2012; 264:484-93. [PMID: 22653187 DOI: 10.1148/radiol.12111883] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To correlate short and long T2* water fractions, derived from ultrashort-echo time (TE) magnetic resonance (MR) imaging, with semiquantitative histopathologic and polarized light microscopic (PLM) assessment of human cadaveric patellae cartilage. MATERIALS AND METHODS Twenty human cadaveric patellae were evaluated by using ultrashort-TE imaging, spin-echo imaging, histopathologic analysis, and PLM, with institutional review board approval. Short and long T2* water components were evaluated for each patella by using bicomponent fitting of ultrashort-TE signal decay. Four to six regions of interest (ROIs) within each patella were chosen for correlation between ultrashort-TE bicomponent analysis, histopathologic grading (Mankin score), and PLM grading (Vaudey score). RESULTS Ultrashort-TE imaging with bicomponent analysis showed two distinct water components with a short T2* and a longer T2* in all patellae. ROI analysis showed that the short T2* fraction was correlated significantly with the Mankin (ρ = 0.66, P < .001) and Vaudey (ρ = 0.68, P < .001) scores. The Mankin scores were weakly positively correlated with T2 (ρ = 0.28, P = .13) and short T2* (ρ = 0.24, P = .14) but were negatively correlated with long T2* (ρ = -0.55, P < .01). The Vaudey scores were weakly positively correlated with T2 (ρ = 0.18, P = .16) and short T2* (ρ = 0.22, P = .14) but were negatively correlated with long T2* (ρ = -0.55, P < .01). CONCLUSION Short T2* water fraction derived from ultrashort-TE imaging with bicomponent analysis correlates significantly with both the Mankin and Vaudey scores and may serve as a biomarker of cartilage degeneration.
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Affiliation(s)
- Chantal Pauli
- Department of Molecular and Experimental Medicine, the Scripps Research Institute, La Jolla, CA, USA
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Conventional and ultrashort time-to-echo magnetic resonance imaging of articular cartilage, meniscus, and intervertebral disk. Top Magn Reson Imaging 2012; 21:275-89. [PMID: 22129641 DOI: 10.1097/rmr.0b013e31823ccebc] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Magnetic resonance imaging (MRI) examination of musculoskeletal tissues is being performed routinely for diagnoses of injury and diseases. Although conventional MRI using spin echo sequences has been effective, a number of important musculoskeletal soft tissues remain "magnetic resonance-invisible" because of their intrinsically short T2 values resulting in a rapid signal decay. This makes visualization and quantitative characterization difficult. With the advent and refinement of ultrashort time-to-echo (UTE) MRI techniques, it is now possible to directly visualize and quantitatively characterize these tissues. This review explores the anatomy, conventional MRI, and UTE MRI of articular cartilage, meniscus of the knee, and intervertebral disks and provides a survey of magnetic resonance studies used to better understand tissue structure, composition, and function, as well as subtle changes in diseases.
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Diaz E, Chung CB, Bae WC, Statum S, Znamirowski R, Bydder GM, Du J. Ultrashort echo time spectroscopic imaging (UTESI): an efficient method for quantifying bound and free water. NMR IN BIOMEDICINE 2012; 25:161-8. [PMID: 21766381 DOI: 10.1002/nbm.1728] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 03/11/2011] [Accepted: 03/17/2011] [Indexed: 05/19/2023]
Abstract
Biological tissues usually contain distinct water compartments with different transverse relaxation times. In this study, two-dimensional, multi-slice, ultrashort echo time spectroscopic imaging (UTESI) was used with bi-component analysis to detect bound and free water components in musculoskeletal tissues. Feasibility studies were performed using numerical simulation. Imaging was performed on bovine cortical bone, human cadaveric menisci and the Achilles' tendons of volunteers. The simulation study demonstrated that UTESI, together with bi-component analysis, could reliably quantify both T(2)* and fractions of the short and long (2)* components. The in vitro and in vivo studies each took less than 14 min. The bound water components showed a short T(2)* of ~0.3 ms for bovine bone, ~1.8 ms for meniscus and ~0.6 ms for the Achilles' tendon. The free water components showed about an order of magnitude longer T(2)* values, with ~2 ms for bovine bone, ~14 ms for meniscus and ~8 ms for the Achilles' tendon. Bound water fractions of up to ~76% for bovine bone, 50% for meniscus and ~75% for the Achilles' tendon were measured. The corresponding free water components were up to ~24% for bovine bone, 50% for meniscus and ~25% for the Achilles' tendon by volume. These results demonstrate that UTESI, combined with bi-component analysis, can quantify the bound and free water components in musculoskeletal tissues in clinically realistic times.
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Affiliation(s)
- Eric Diaz
- Department of Radiology, University of California, San Diego, CA 92103–8226, USA
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Correction of susceptibility-induced GRE phase shift for accurate PRFS thermometry proximal to cryoablation iceball. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2011; 25:23-31. [DOI: 10.1007/s10334-011-0277-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/23/2011] [Accepted: 08/10/2011] [Indexed: 10/17/2022]
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Du J, Bydder M, Takahashi AM, Carl M, Chung CB, Bydder GM. Short T2 contrast with three-dimensional ultrashort echo time imaging. Magn Reson Imaging 2011; 29:470-82. [PMID: 21440400 DOI: 10.1016/j.mri.2010.11.003] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Accepted: 11/28/2010] [Indexed: 10/18/2022]
Abstract
There is increasing interest in imaging short T2 species which show little or no signal with conventional magnetic resonance (MR) pulse sequences. In this paper, we describe the use of three-dimensional ultrashort echo time (3D UTE) sequences with TEs down to 8 μs for imaging of these species. Image contrast was generated with acquisitions using dual echo 3D UTE with echo subtraction, dual echo 3D UTE with rescaled subtraction, long T2 saturation 3D UTE, long T2 saturation dual echo 3D UTE with echo subtraction, single adiabatic inversion recovery 3D UTE, single adiabatic inversion recovery dual echo 3D UTE with echo subtraction and dual adiabatic inversion recovery 3D UTE. The feasibility of using these approaches was demonstrated in in vitro and in vivo imaging of calcified cartilage, aponeuroses, menisci, tendons, ligaments and cortical bone with a 3-T clinical MR scanner. Signal-to-noise ratios and contrast-to-noise ratios were used to compare the techniques.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, CA 92103-8226, USA.
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Lu A, Daniel BL, Kaye E, Butts Pauly K. MRI of frozen tissue demonstrates a phase shift. Magn Reson Med 2011; 66:1582-9. [PMID: 21630347 DOI: 10.1002/mrm.22953] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 03/04/2011] [Accepted: 03/14/2011] [Indexed: 11/11/2022]
Abstract
While temperature mapping is desired during cryosurgery for prostate cancer treatment, an effective approach for this purpose is still needed. We have demonstrated a phase shift with temperature in our in vivo canine experiments and ex vivo tissue sample experiments within the frozen tissue. The phase shift is much larger (~0.7 °/°C with an echo time of 0.1 ms at 0.5 T) in magnitude than that predicted by conventional proton resonant frequency shift (0.008 °/°C). It shows little dependence on the echo times used and thus is not due to a frequency change, although frequency-dependent phase shift has been observed near the frozen tissue. This phase shift varies monotonically with temperature within the frozen tissue and therefore may be potentially used as a novel temperature mapping approach in cryoablation applications.
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Affiliation(s)
- Aiming Lu
- Center for MR Research, University of Illinois Medical Center, Chicago, Illinois 60612, USA.
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Du J, Carl M, Bydder M, Takahashi A, Chung CB, Bydder GM. Qualitative and quantitative ultrashort echo time (UTE) imaging of cortical bone. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:304-11. [PMID: 20980179 DOI: 10.1016/j.jmr.2010.09.013] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Revised: 09/15/2010] [Accepted: 09/19/2010] [Indexed: 05/05/2023]
Abstract
We describe the use of two-dimensional ultrashort echo time (2D UTE) sequences with minimum TEs of 8 μs to image and quantify cortical bone on a clinical 3T scanner. An adiabatic inversion pulse was used for long T(2) water and fat signal suppression. Adiabatic inversion prepared UTE acquisitions with varying TEs were used for T(2) measurement. Saturation recovery UTE acquisitions were used for T(1) measurement. Bone water concentration was measured with the aid of an external reference phantom. UTE techniques were evaluated on cadaveric specimens and healthy volunteers. A signal-to-noise ratio of around 30, contrast-to-noise ratio of around 27/20 between bone and muscle/fat were achieved in tibia in vivo with a nominal voxel size of 0.23 × 0.23 × 6.0 mm(3) in a scan time of 5 min. A mean T(1) of 223 ± 11 ms and mean T(2) of 390 ± 19 μs were found. Mean bone water concentrations of 23.3 ± 1.6% with UTE and 21.7 ± 1.3% with adiabatic inversion prepared UTE sequences were found in tibia in five normal volunteers. The results show that in vivo qualitative and quantitative evaluation of cortical bone is feasible with 2D UTE sequences.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, United States.
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Du J, Corbeil J, Znamirowski R, Angle N, Peterson M, Bydder GM, Kahn AM. Direct imaging and quantification of carotid plaque calcification. Magn Reson Med 2010; 65:1013-20. [PMID: 21413065 DOI: 10.1002/mrm.22682] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 09/10/2010] [Accepted: 09/19/2010] [Indexed: 11/09/2022]
Abstract
Carotid plaque calcification normally appears as a signal void with clinical MR sequences. Here, we describe the use of an adiabatic inversion recovery prepared two-dimensional ultrashort echo time sequence to image and characterize carotid plaque calcification using a clinical 3-T scanner. T(1), T 2*, and free water content were measured for seven carotid samples, and the results were compared with micro-CT imaging. Conventional gradient echo and fast spin echo images were also acquired for comparison. Correlations between T(1), T 2*, free water concentration, and mineral density were performed. There was a close correspondence between inversion recovery prepared two-dimensional ultrashort echo time morphologic and micro-CT appearances. Carotid plaque calcification varied significantly from sample to sample, with T(1) s ranging from 94 ± 19 to 328 ± 21 msec, T 2*s ranging from 0.31 ± 0.12 to 2.15 ± 0.25 msec, and free water concentration ranging from 5.7 ± 2.3% to 16.8 ± 3.4%. There was a significant positive correlation between T(1)(R = 0.709; P < 0.074), T 2* (R = 0.816; P < 0.025), and free water concentration, a negative correlation between T(1) (R = 0.773; P < 0.042), T 2* (R = 0.948; P < 0.001) and CT measured mineral density, and a negative correlation between free water concentration (R = 0.936; P < 0.002) and mineral density.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, California 92103-8226, USA.
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Lu A, Atkinson IC, Claiborne TC, Damen FC, Thulborn KR. Quantitative sodium imaging with a flexible twisted projection pulse sequence. Magn Reson Med 2010; 63:1583-93. [PMID: 20512862 DOI: 10.1002/mrm.22381] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The quantification of sodium MR images from an arbitrary intensity scale into a bioscale fosters image interpretation in terms of the spatially resolved biochemical process of sodium ion homeostasis. A methodology for quantifying tissue sodium concentration using a flexible twisted projection imaging sequence is proposed that allows for optimization of tradeoffs between readout time, signal-to-noise ratio efficiency, and sensitivity to static field susceptibility artifacts. The gradient amplitude supported by the slew rate at each k-space radius regularizes the readout gradient waveform design to avoid slew rate violation. Static field inhomogeneity artifacts are corrected using a frequency-segmented conjugate phase reconstruction approach, with field maps obtained quickly from coregistered proton imaging. High-quality quantitative sodium images have been achieved in phantom and volunteer studies with real isotropic spatial resolution of 7.5 x 7.5 x 7.5 mm(3) for the slow T(2) component in approximately 8 min on a clinical 3-T scanner. After correcting for coil sensitivity inhomogeneity and water fraction, the tissue sodium concentration in gray matter and white matter was measured to be 36.6 +/- 0.6 micromol/g wet weight and 27.6 +/- 1.2 micromol/g wet weight, respectively.
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Affiliation(s)
- Aiming Lu
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Springer F, Steidle G, Martirosian P, Claussen CD, Schick F. Effects of in-pulse transverse relaxation in 3D ultrashort echo time sequences: analytical derivation, comparison to numerical simulation and experimental application at 3T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 206:88-96. [PMID: 20637661 DOI: 10.1016/j.jmr.2010.06.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 05/21/2010] [Accepted: 06/17/2010] [Indexed: 05/29/2023]
Abstract
The introduction of ultrashort-echo-time-(UTE)-sequences to clinical whole-body MR scanners has opened up the field of MR characterization of materials or tissues with extremely fast signal decay. If the transverse relaxation time is in the range of the RF-pulse duration, approximation of the RF-pulse by an instantaneous rotation applied at the middle of the RF-pulse and immediately followed by free relaxation will lead to a distinctly underestimated echo signal. Thus, the regular Ernst equation is not adequate to correctly describe steady state signal under those conditions. The paper presents an analytically derived modified Ernst equation, which correctly describes in-pulse relaxation of transverse magnetization under typical conditions: The equation is valid for rectangular excitation pulses, usually applied in 3D UTE sequences. Longitudinal relaxation time of the specimen must be clearly longer than RF-pulse duration, which is fulfilled for tendons and bony structures as well as many solid materials. Under these conditions, the proposed modified Ernst equation enables adequate and relatively simple calculation of the magnetization of materials or tissues. Analytically derived data are compared to numerical results obtained by using an established Runge-Kutta-algorithm based on the Bloch equations. Validity of the new approach was also tested by systematical measurements of a solid polymeric material on a 3T whole-body MR scanner. Thus, the presented modified Ernst equation provides a suitable basis for T1 measurements, even in tissues with T2 values as short as the RF-pulse duration: independent of RF-pulse duration, the 'variable flip angle method' led to consistent results of longitudinal relaxation time T1, if the T2 relaxation time of the material of interest is known as well.
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Affiliation(s)
- Fabian Springer
- Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital, 72076 Tübingen, Germany.
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Kaye EA, Josan S, Lu A, Rosenberg J, Daniel BL, Pauly KB. Consistency of signal intensity and T2* in frozen ex vivo heart muscle, kidney, and liver tissue. J Magn Reson Imaging 2010; 31:719-24. [PMID: 20187218 DOI: 10.1002/jmri.22029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To investigate tissue dependence of the MRI-based thermometry in frozen tissue by quantification and comparison of signal intensity and T2* of ex vivo frozen tissue of three different types: heart muscle, kidney, and liver. MATERIALS AND METHODS Tissue samples were frozen and imaged on a 0.5 Tesla MRI scanner with ultrashort echo time (UTE) sequence. Signal intensity and T2* were determined as the temperature of the tissue samples was decreased from room temperature to approximately -40 degrees C. Statistical analysis was performed for (-20 degrees C, -5 degrees C) temperature interval. RESULTS The findings of this study demonstrate that signal intensity and T2* are consistent across three types of tissue for (-20 degrees C, -5 degrees C) temperature interval. CONCLUSION Both parameters can be used to calculate a single temperature calibration curve for all three types of tissue and potentially in the future serve as a foundation for tissue-independent MRI-based thermometry.
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Affiliation(s)
- Elena A Kaye
- Department of Electrical Engineering, Stanford University, Stanford, California, USA.
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Du J, Carl M, Diaz E, Takahashi A, Han E, Szeverenyi NM, Chung CB, Bydder GM. Ultrashort TE T
1
rho (UTE T
1
rho) imaging of the Achilles tendon and meniscus. Magn Reson Med 2010; 64:834-42. [DOI: 10.1002/mrm.22474] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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O'Brien KR, Myerson SG, Cowan BR, Young AA, Robson MD. Phase contrast ultrashort TE: A more reliable technique for measurement of high-velocity turbulent stenotic jets. Magn Reson Med 2009; 62:626-36. [PMID: 19488986 DOI: 10.1002/mrm.22051] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Kieran R O'Brien
- Bioengineering Institute, University of Auckland, Auckland, New Zealand.
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Josan S, Bouley DM, van den Bosch M, Daniel BL, Butts Pauly K. MRI-guided cryoablation: In vivo assessment of focal canine prostate cryolesions. J Magn Reson Imaging 2009; 30:169-76. [PMID: 19557805 DOI: 10.1002/jmri.21827] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To analyze the appearance of acute and chronic canine prostate cryolesions on T1-weighted (T1w) and T2-weighted (T2w) magnetic resonance imaging (MRI) and compare them with contrast-enhanced (CE) MRI and histology for a variety of freezing protocols. MATERIALS AND METHODS Three different freezing protocols were used in canine prostate cryoablation experiments. Six acute and seven chronic (survival times ranging between 4-53 days) experiments were performed. The change in T2w signal intensity was correlated with freezing protocol parameters. The lesion area on T2w MRI was compared to CE-MRI. Histopathologic evaluation of the cryolesions was performed and visually compared to the appearance on MRI. RESULTS The T2w signal increased from pre- to postfreeze at the site of the cryolesion, and the enhancement was higher for smaller freeze area and duration. The T2w lesion area was between the CE nonperfused area and the hyperenhancing CE rim. The appearance of the lesion on T1w and T2w imaging over time correlated with outcome on pathology. CONCLUSION T1w and T2w MRI can potentially be used to assess cryolesions and to monitor tissue response over time following cryoablation.
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Affiliation(s)
- Sonal Josan
- Department of Electrical Engineering, Stanford University, Stanford, California, USA.
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46
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Du J, Chiang AJT, Chung CB, Statum S, Znamirowski R, Takahashi A, Bydder GM. Orientational analysis of the Achilles tendon and enthesis using an ultrashort echo time spectroscopic imaging sequence. Magn Reson Imaging 2009; 28:178-84. [PMID: 19695811 DOI: 10.1016/j.mri.2009.06.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 06/10/2009] [Accepted: 06/25/2009] [Indexed: 11/19/2022]
Abstract
Tendons and entheses are magnetic resonance (MR) "invisible" when imaged with conventional clinical pulse sequences. When the highly ordered, collagen-rich fibers in tendons and entheses are placed at the magic angle, dipolar interactions are decreased and their T2s are often considerably increased. The bulk magnetic susceptibility of tendons and entheses also varies with orientation to B(0), leading to a direction-dependent resonance frequency shift. Ultrashort echo time (UTE) sequences with a minimum TE of 8 mus provide high signal from both tendons and entheses. The combination of a UTE sequence with an interleaved undersampled variable TE acquisition scheme provides a new approach for fast spectroscopic imaging of short T2 tissues. This UTE spectroscopic imaging (UTESI) technique provides quantitative information including T2, chemical shift and resonance frequency shift due to bulk susceptibility effect. In this article, the orientational effects on tendons and entheses were investigated using a UTESI sequence on a clinical 3-T scanner. T2 was found to increase fivefold for tendons and twofold for entheses due to the magic angle effect. A resonance frequency shift up to 1.2 ppm was observed for both tendons and entheses due to the bulk susceptibility effect when their orientation was changed from 0 degree to 90 degrees relative to B(0).
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, CA 92103-8756, USA.
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