Morteza Bakhtiary

Alumni of the Department High-Field Magnetic Resonance

Main Focus

The energy supply in cells is provided by molecules that contain phosphorus. Especially PCr (Phosphocreatine) and ATP (Adenosine-Tri-Phosphate) carry the energy needed for most processes in the brain and other organs. Magnetic Resonance Spectroscopy has the potential to quantitatively detect these substances in living subjects noninvasively.

In spite of the high amount of potential applications of this technique, its low sensitivity still prevents its widespread use in research and clinical routine, imposing strong constraints on the spatial resolution and accuracy of measurements. These limitations can be removed by using MR instruments that make use of an ultra-high magnetic field.

The goal of this project is to implement spatially resolved phosphorus spectroscopy on an MR scanner with a field strength of 9.4 T. It is expected that this field, which is six times higher than that of standard instruments, will allow accurate and highly resolved imaging of the distribution of the metabolites in the brain.

Investigation of the energy metabolism in the human brain during stimulation using NMR phosphorus spectroscopy at 9.4 Tesla

Introduction

Phosphorus plays an important role in growth, development, bone formation, acid/base regulation, and cellular metabolism [1]. The phosphorus metabolite ATP constitutes the main energy store in the cells, supplying the energy needed for almost all metabolic processes. Especially in the brain, with its high perfusion and energy requirements, investigations of the phosphorus metabolism can, together with other complimentary modalities like BOLD and CBF measurements, give valuable information on brain function.

In vivo MRS faces many technical challenges because of its unfavorable NMR sensitivity, leading to a limited spatial resolution. One efficient (though expensive) solution is the use of high-field MRI/MRS scanners. In addition to increasing the sensitivity, higher magnetic fields lead to larger chemical shift dispersion, reducing overlap of signals and thus improving the accuracy of the quantification of metabolite concentrations. Further advantages are expected based on previous measurements at 7T (a decrease in T1 of 31P with increasing field strength). Thus, it is expected that in vivo 31P MRS may gain significant SNR at ultrahigh fields [2] that improve temporal resolution as well as spatial resolution for evaluating functional changes in brain.

Goals

The goal of this project is to implement spatially resolved phosphorus spectroscopy and echo planar spectroscopic imaging on an MR scanner with a field strength of 9.4 T to investigate the energy metabolism in the human brain at rest and during stimulation. It is expected that this field, which is six times higher than that of standard instruments (1.5T), will allow accurate and highly resolved images of the distribution of the metabolites in the brain.

Initial Results

Tibial Bone Marrow Relaxometry at 9.4 T

Proton spectroscopy in bone marrow will be used for developing protocols for measuring, post processing and quantifying the spectroscopic data due to the much shorter duration and higher sensitivity of the experiments. Tibial bone marrow relaxometry was done at 9.4 T using a single voxel STEAM inversion recovery protocol with an 8 channel transmit coil and a 2 channel receiver quadrature surface coil (Fig 1).

(a)

(b)

Fig 1: a) Signal Intensity with increasing inversion times for T1 measurements b) Signal intensity at different echo times for T2 measurement

Design and Construction of a 31P surface coil for 9.4T (31P MRS of the human calf at 3T and 9.4T)

First measurements with phosphorus MRS were obtained from the human calf at a clinical scanner with a field strength of 3T. To make it possible to gain first experiences in 31P spectroscopy at high field, a quadrature surface coil consisting of two circular loops positioned adjacent to the sample for spin excitation and detection of the signals was designed and constructed. Additional required hardware, preamplifiers, T/R switches and hybrids for the 31P Larmor frequency of 161.98 MHz were built (Fig 2). Due to its geometry, this coil is only capable of covering a small volume and will therefore mainly be used to obtain first experiences with 31P spectroscopy in measurements of the human calf muscle. This coil will be used in combination with an existing proton head coil for imaging and shimming. Fig 3-a shows spectra from the human calf with low repetition time and short scan time with good metabolite dispersion and higher SNR in comparison with 3T (Fig 3-b).

Fig.2. Constructed phosphorous Quadrature surface coil for 9.4T

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(b)

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Fig. 3.a)Sample 31P spectrum of human calf at 9.4T (scan time=0:08) b) Sample 31P spectrum of human calf at 3T (scan time=1:08) c)31P spectrum with molecular structures of prominent phosphorous molecules (Pi, PCr and ATP) with an important role in energy metabolism.

31P MRS of the human brain with a surface coil at 9.4T

A surface coil used for both excitation and reception restricts the observable volume to a small area close to the coil, but there with high sensitivity. Figure 4 shows a sample 31P spectrum from the human brain with low repetition time and with very short scan time, showing good metabolite dispersion and sufficient SNR.

Fig. 4) Sample 31P spectrum of the human brain at 9.4T (scan time=1:07)

Design and construction of a 31P head coil for 9.4T

Based on the experiences gained with the simple surface coil, a 1H/31P coil assembly for optimum coverage of the entire brain designed and constructed (Fig. 5). The 31P part consists of 4 loop array transmit channels and 24 receive channels positioned around a helmet near the head. The 1H part consists of 4 transmit/receive dipole channels around the 31P array.

Fig. 5) 1H/31P coil for 9.4 T

Fig 6. a)sagittal view of 3D localized 31P scanned with a volume coil at 9.4 T  (scan time=19:12)  b) Coronal view c)localized spectrum with position shown as blue box in d, e and f with all important phosphorous metabolites including 1)PME 2)Pi, 3)PDE, 4)PCr, 5)ATP? and 6)ATP?

Future work

Measurement of 31P CSI at rest

We will measure 31P CSI at rest to optimize the protocols for brain measurement and detect the limitations on metabolite stability. The limitations in spatial and temporal resolution will be determined and highly accurate values for relaxation times, baseline concentrations and creatine kinase rate will be measured.

Determination of energy consumption, ATP production and pH in the active brain

Finally, the reaction of the brain on different stimuli will be examined. Changes in metabolite concentrations, pH and kinetics will be examined with fast CSI techniques at high spatial resolution. The detected variations will be related to measurement of BOLD and CBF. Combining those techniques will help to improve the current models of brain function.

References

1- Disease of Bone and Mineral Metabolism, Frederick Singer, Endotext.com 2008, chapter 10, Andrew Arnold - Editor

2- Wei Chen, Xiao-Hong Zhu, Dynamics Study of Cerebral Bioenergetics and Brain Function Using in vivo Multinuclear MRS Approaches, Concepts in Magnetic Resonance Part A, Vol 27A(2) 84-121 (2005).

Curriculum Vitae

Education

since July 2010: PhD student, Max Planck Institute for Biological Cybernetics, Tubingen, Germany

Thesis: "Investigation of the energy metabolism in the human brain during stimulation using NMR phosphorus spectroscopy at 9.4 Tesla"

23 September 2001 - 3 Jan 2005: M.Sc in Medical Physics, Tehran University of Medical Sciences, Tehran, Iran

Thesis: “Optimization of MR-Relaxometry for BMD-measurements and its Correlation with DEXA”

23 September 1997 - 21 July 2001: B.Sc in Applied Physics (Solid state), Amirkabir University of Technology, Tehran, Iran

Awards

Feb. 2005: ISCD Young Investigator Award, ISCD2005, New Orleans-USA. (Morteza Bakhtiary, Nader Riyahi-Alam, Mohammad Ali Oghabian, Ali Ghasemzadeh, Hossein Qanaaty, “Optimization of MR-Relaxometry for BMD-measurements and its Correlation with DEXA”, ISCD 2005 Annual Meeing, 16-19 Feb. 2005, New Orleans-USA.)

2001: First Rank of Entrance exam for Master of Science in Medical Physics, Iran Ministry of Health & Rehabilitations, Tehran, Iran

Research Experiences

5 Jan 2005 - 20 August 2009: Research Assistant (Part time), Tehran Univ. of medical sciences, Tehran-Iran.

Projects included:

- “Design and implementing a high resolution MR based polymer Dosimetry versus film densitometry: asystematic study based on the modulation Transfer function approach”, Apr 2006-2007.

- “The Assessment of Structural Variations of MS Plaques in Clinically Isolated Syndrome (CIS) and Definite MS (CDMS) Patients by Comparison of Magnetization Transfer Imaging (MTI) Parameters”, Apr. 2006-2008.

- “Investigation of Reproducibility of Geometric Distortion in MRI Based on Phantom Study”, 2005-2006.

- “The Evaluation of MRI BMD Relaxometry and Determination of Correlation Coefficient with DEXA Technique”, 2004-2006.

- “Prognostic Value of Brain Tissue Pathological Changes in Patients with Clinically Isolated Syndromes (CIS) Suggestive of Multiple Sclerosis Using Magnetization Transfer Ratio (MTR)”, 2007-2009.

- “Evaluation of MRI-based Polymer Gel Dosimetry for Measurement of CT Dose Index (CTDI) on 64 slices CT Scanners”, 2008-2009

- “Optimizing Platelet-based MPLE Denoising of brain and cardiac SPECT Images using ROC curve”, 2009

- “Evaluation of Computer Aided Diagnosis method in detection of Microcalcifications clusters in Digital mammography”, 2009

- “Development of a T1 Contrast Agent for Magnetic Resonance Imaging using Gd2O3 Nanoparticles”, 2008-2010

Conferences Attended:

2012:

- 3rd Scientific Symposium on Ultrahigh Field MR, 8 June 2012, Berlin-Germany.

2009:

- WC2009, 7-12 Sep. 2009, Munich-Germany.

- International Congress of Neurology & Clinical Electrophysiology of Iran, 19-22 May, 2009, Tehran, Iran.

2007:

- 18th international Annual Meeting of The Cancer Institute of Iran: Head&Neck Tumors, 26-28 October, 2007, Tehran-Iran.

- IIC 2007, The First Iranian Imaging Informatics Conference, 6-7 September 2007, Tehran-Iran.

2006:

- 1St Human, Life and Radiation Conference, Rafsanjan University of Medical Sciences, 29-31 October, 2006, Rafsanjan-Iran.

- WC2006, 27Aug-1Sep. 2006, Seoul-Korea.

2005:

- The 20th Iranian Congress of Radiology, 28-30 Jan. 2005, Tehran-Iran.

2004:

- The first International Seminar on prevention, diagnosis and treatment of osteoporosis, 23-24 Sep. 2004, The Conference Center, Imam Hospital, Tehran-Iran.

Work Experiences

20 June 2009 - 20 August 2009: Salesman & Technical Support (Radiology and Radiotherapy), Lyan System Pars Co., Tehran-Iran

Duties:

- Scientific support of Radiology and Radiotherapy systems especially MRI & Whole body Gamma Knife

- Radiology and Radiotherapy systems sales

14 May 2008 - 14 May 2009: R&D (Laser Range Finder), Rayan Roshd Afzar Co., Baharestan Industrial city, Karaj-Iran

- Montage active Q-Switched Nd:YAG LASER

- Design Laser receiver using Avalanche Photo diode detector

- ATMEGA128 micro controller programming using C++ (CodeVision) for time measurement by TDC-GP1.

31 October 2006 - 14 May 2008: Technical support, Member of Directing board & stockholder, Green Link Data Processor Medical Engineering Co. Ltd., Tehran, Iran

Duties:

- Technical support of 3D Radiotherapy treatment planning system software (CorePLAN, Seoul C&J, Seoul, Korea).

- Technical support of Picture Archiving & Communication System (APAX, Seoul C&J, Seoul, Korea).

- Lecturer

22 May 2006 – 23 September 2006: Medical Imaging Center (Part time), Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran-Iran.

Duties: Teaching the MRI principles, pulse sequences & applications

Publications

JOURNAL PAPERS:

1- Reza Moghadam-Drodkhani, Nader Riyahi-Alam, Abbas Takavar, Kavous Firoznia, Peiman Hadad, Behrooz Rafiee, Morteza Bakhtiary, Zohre Tizmaghz, Ehsan Mohammadi, “Investigation of spatial resolution of the MR based polymer gel dosimetry versus film densitometry using dose modulation transfer function”, Iranian Journal of Medical Physics, Volume 8, No.1(30), Spring 2011, 55-64.

2- Leaila Karimi-Afshar, Nader Riahi Alam, Mohammadreza Ay, Mahmoud Allahverdi, Tayeb Alahverdi purfallah, Hassan Hashemi, Ahmad Farahani, Behrooz eafie, Morteza Bakhtiary, “Evaluation of MRI-based Polymer Gel Dosimetry for Measurement of CT Dose Index (CTDI) on 64 slices CT Scanners”, Iranian Journal of Medical Physics, Vol.6, No.2 (23), Summer 2009, 59-70.

3- Mohammad Khoshnevisan (Australia), Saeid Nahavandi (Australia), Sukanto Bhattacharya (USA), Morteza Bakhtiary (Iran), “fMRI studies in neuro-fuzzy and behavioral finance: a case based approach”, Investment Management and Financial Innovations, Volume 5, Issue 3, 2008, 111-121.

4- Hamed Ekhtiari, Arian Behzadi, Habib Ganjahi, Azarakhsh Mokri, Hanieh Edalati, Morteza Bakhtiari, Naghmeh Rabiee, Mohammad Ali Oghabian, “Functional Neuroimaging Study of Brain Activation due to Craving in Heroin Intravenous Users”, Iranian Journal of Psychiatry and Clinical Psychology, Vol. 14, No. 3, Fall 2008, 269-280.

5- Masoomeh Fooladi, Nader Riahi Alam, Mohammad Hossein Harirchyan, Kavoos Firuznia, Mohammad Ali Oghabian, Majid Shakiba, Behrooz Rafie, Morteza Bakhtiary, “The Assessment of Structural Changes in MS Plaques and Normal Appearing White Matter Using Quantitative Magnetization Transfer Imaging (MTI)”, Iranian Journal of Medical Physics, Vol.4, No.2(16&17), Autumn &winter 2008.

6- M. Fooladi, N. Riyahi Alam, MH. Harirchian, K. Firuznia, MA. Oghabian, B. Rafie, M. Bakhtiary, “Prognostic Value of Brain Tissue Pathological Changes in Patients with Clinically Isolated Syndromes (CIS) Suggestive of Multiple Sclerosis Using Magnetization Transfer Ratio (MTR)”, Conf Proc IEEE Eng Med Biol Soc. 2007;1:62031-3. PMID: 18002384.

7- A. Mirzajani, M.A. Oghabian, N. Riyahi-Alam, H. Saberi, K. Firouznia, M. Bakhtiary, “Spatial Frequency Modulates the Human Visual Cortical Response to Temporal Frequency Variation: An fmri Study”, Conf Proc IEEE Eng Med Biol Soc. 2006;1:1032-5. PMID: 17946438.

8- N. Riyahi-Alam, N. Alibabaei, A. Takavar, M. Sohrabi, A. Fard-Esfahani, M.A. Oghabian, M. Bakhtiary, “Platelet-Based MPLE Method for Denoising of Brain and Cardiac SPECT Images”, Conf Proc IEEE Eng Med Biol Soc. 2006;1:4787-90. PMID: 17946651.

9- M. Bakhtiary, N. Riahi Alam, M.A. Oghabian, A. Ghasemzadeh, H. Ghanaati, S. Sarkar, “MRI Relaxometry BMD Measurements Using Conventional Phase Symmetrized Rapid Increase Flip Spin Echo and Standard Gradient Echo and Its Correlation with DXA”, Medical Physics, Vol. 33, Issue 6, p 2012, June 2006.

10- M. Ashkanmehr, N. Riyahi Alam, M.A. Oghabian, A. Ghasemzadeh, M. Bakhtiary, H. Ghanaati, H. Hashemi, M. Pakravan, N. Shakeri, “Assessment of Reproducibility of Geometric Distortion in MRI using Phantom Measurements”, Iranian Journal of Medical Physics, Vol. 2, No. 8, pp 1-8, Autumn 2005.

11- Riyahi Alam N, Bakhtiary M, Oghabian M, Sarkar S, Ghasemzadeh A, Ghanaati H, Larijani B, Hamidy Z, Shakery N, “Optimization of MR-Relaxometry for BMD-measurements and its Correlation with DEXA”, Conf Proc IEEE Eng Med Biol Soc. 2005;1(1):638-641. PMID: 17282263.

12- M. Bakhtiary, N. Riahi Alam, M.A. Oghabian, A. Ghasemzadeh, H. Ghenaati, S. Sarkar, B. Larijani, Z. Hamidi Abarghoie, N. Shakeri, “Optimization of MRI Relaxometry for BMD Measurement and Its Correlation with DEXA”, Scientific Journal of Hamedan University of Medical Sciences & Health Services, Vol. 12, No. 2, pp 32-38, Summer 2005.

JOURNAL ABSTRACTS:

1- Amirreza Azizian, Morteza Bakhtiary, Mahdie Jajroudi, Hassan Ghanaati, “PACS in Cardiology: Tele-ECG”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 28, 2007.

2- Amirreza Azizian, Morteza Bakhtiary, Mahdie Jajroudi, Hassan Ghanaati, “E-learning in Iran”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 23, 2007.

3- Morteza Bakhtiary, “Integrated Viewer using indoor RIS”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 20, 2007.

4- Morteza Bakhtiary, Hassan Ghanaati, “Storage Management: short time vs. long time; Role of compression”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 16, 2007.

5- Morteza Bakhtiary, Hassan Ghanaati, “APAX Server and Viewer”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 12, 2007.

6- Morteza Bakhtiary, Mahdie Jajroudi, “Ergonomic aspects of medical image history using multiple monitors”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 9, 2007.

7- Morteza Bakhtiary, Amirreza Azizian, “CorePLAN Radiotherapy Planning System Based on PACS”, Iranian Journal of Radiology, Vol. 4, Supplement 2, pp 8-9, 2007.

8- Morteza Bakhtiary, Hassan Ghanaati, “Enterprise PACS as a solution”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 7, 2007.

9- Abstracts, Journal of clinical densitometry, Vol. 8, issue 2, pp 228-249, 2006.

Lectures:

1- “Novel application of MRI-polymer gel dosimeter for measurement of CTDI on X-ray 64 slices CT scanner”, WC2009, 7-12Sep. 2009, Munich-Germany.

2- “Brain White Matter Pathological Assessment in MS Clinically Isolated Syndrome and Relapsing-Remitting Patients using Quantitative Magnetization Transfer Imaging (qMTI)”, WC2009, 7-12Sep. 2009, Munich-Germany.

3- “Evaluation of Disease burden in NAWM of relapsing – remitting , clinically isolated syndrome MS patients using magnetization transfer imaging”, International Congress of Neurology & Clinical Electrophysiology of Iran, 19-22 May, 2009, Tehran, Iran.

4- “Integrated Viewer using indoor RIS”, IIC 2007, The First Iranian Imaging Informatics Conference, 6-7 September 2007, Tehran. Iran.

5- “Storage Management: short time vs. long time; Role of compression”, IIC 2007, The First Iranian Imaging Informatics Conference, 6-7 September 2007, Tehran. Iran.

6- “Enterprise PACS as a solution”, IIC 2007, The First Iranian Imaging Informatics Conference, 6-7 September 2007, Tehran. Iran.

7- “CorePLAN Radiotherapy Planning System Based on PACS”, IIC 2007, The First Iranian Imaging Informatics Conference, 6-7 September 2007, Tehran. Iran.

8- “Ergonomic aspects of medical image history using multiple monitors”, IIC 2007, The First Iranian Imaging Informatics Conference, 6-7 September 2007, Tehran. Iran.

9- “APAX Server and Viewer”, IIC 2007, The First Iranian Imaging Informatics Conference, 6-7 September 2007, Tehran. Iran.

10- “MRI Relaxometry BMD Measurements using Conventional Rapid Increased Flip Spin Echo and Gradient Echo”, WC2006, 27Aug-1Sep. 2006, Seoul-Korea.

11- “Optimization of visual tasks for detecting visual cortex activity in fMRI studies”, WC2006, 27Aug-1Sep. 2006, Seoul-Korea.

12- “Spatial frequency modulates the human visual cortical response to temporal frequency variation: an fMRI study”, WC2006, 27Aug-1Sep. 2006, Seoul-Korea.

Posters:

1- Morteza Bakhtiary, Guanmony Shajan, Jens Hoffmann, Klaus Scheffler, Rolf Pohmann, ”31P-spectroscopy on humans at 9.4T in combinaion with a patch antenna for proton imaging: Initial results”, 21st Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2013), Salt Lake City, UT, USA, 20-26 April 2013.

2- Morteza Bakhtiary, Rolf Pohmann, Shajan Guanmony, Klaus Scheffler, ”NMR phosphorus spectroscopy at 9.4 Tesla using construted Quadrature surface coil”, 3rd Scientific Symposium on Ultrahigh Field MR, 8 June 2012, Berlin-Germany.

3- Zhaleh Behrouzkia, Nader Riyahi-Alam, Soheila Haghgoo Jahromi, Mohammad Hossein Moddaresi, Alexander Seifalian, Mojtaba Saffari, Morteza Bakhtiary, “Development of a T1 Contrast Agent for Magnetic Resonance Imaging using Gd2O3 Nanoparticles”, WC2009, 7-12Sep. 2009, Munich-Germany.

4- Ramin Khoie, Morteza Bakhtiary, Mohammad Esmaeili ,“Time of Flight Laser Range Finder using Active Q-switched Nd:YAG Laser”,The 1st National Conference on Optics & Laser Engineering (NCOLE2009), 20-21 May, 2009, Shahinshahr, Isfahan-Iran.

5- S.R. Mahdavi, M. Bakhtiary, A.R. Nikoofar, “Three-dimensional planning application in head and neck radiation therapy”, 18th international Annual Meeting of The Cancer Institute of Iran: Head&Neck Tumors, Iran, 26-28 October, 2007.

6- Amirreza Azizian, Morteza Bakhtiary, Mahdie Jajroudi, Hassan Ghanaati, “PACS in Cardiology: Tele-ECG”, Iranian Journal of Radiology, Vol. 4, Supplement 2, p 28, 2007.

7- M. Fooladi, N. Riyahi Alam, MH. Harirchian, K. Firuznia, MA. Oghabian, B. Rafee, M. Bakhtiary, “Prognostic Value of Brain Tissue Pathological Changes in Patients with Clinically Isolated Syndromes (CIS) Suggestive of Multiple Sclerosis Using Magnetization Transfer Ratio (MTR)”, 29th IEEE, EMBS Annual International Conference, Lyon, France, 23rd - 26th August, 2007.

8- M. Bakhtiary, N. Ryiahi-Alam, M.A. Oghabian, A. Ghasemzadeh, H. Ghanaati, S. Sarkar, B. Larijani, Z. Hamidy-Abarghouie, N. Shakery, “BONE MINERAL DENSITY MEASUREMENTS USING MRI RELAXOMETRY”, 1St Human, Life and Radiation Conference, Rafsanjan University of Medical Sciences, Iran, 29-31 October, 2006.

9- A. Mirzajani, M.A. Oghabian, N. Riyahi-Alam, H. Saberi, K. Firouznia, M. Bakhtiary, “Spatial Frequency Modulates the Human Visual Cortical Response to Temporal Frequency Variation: An fmri Study”, 28th IEEE, EMBS Annual International Conference, New York City, USA, Aug 30-Sept 3, 2006.

10- N. Riyahi-Alam, N. Alibabaei, A. Takavar, M. Sohrabi, A. Fard-Esfahani, M.A. Oghabian, M. Bakhtiary, “Platelet-Based MPLE Method for Denoising of Brain and Cardiac SPECT Images”, 28th IEEE, EMBS Annual International Conference, New York City, USA, Aug 30-Sept 3, 2006.

11- M. Ashkanmehr, N. Riyahi–Alam, M.A. Oghabian, A. Ghasemzadeh, M. Bakhtiary, H. Ghanaati, M. Pakravan, “Assessment of Reproducibility of Geometric Distortion in MRI using Phantom Measurements”, WC2006, 27Aug-1Sep. 2006, Seoul-Korea.

12- Morteza Bakhtiary, Nader Riyahi-Alam, Mohammad Ali Oghabian, Ali Ghasemzadeh, Hossein Qanaaty, “Optimization of MR-Relaxometry for BMD-measurements and its Correlation with DEXA”, ISCD 2005 Annual Meeing, 16-19 Feb. 2005, New Orleans-USA.

13- M. Bakhtiary, N. Riahi Alam, M.A. Oghabian, A. Ghasemzadeh, H. Ghanaati, “The Optimization of Magnetic Resonance Relaxometry for Bone Mineral Densitometry and its correlation with DEXA”, the first International Seminar on prevention, diagnosis and treatment of osteoporosis, 23-24 Sep. 2004, The Conference Center, Imam Hospital, Tehran-Iran.

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