Pavan Poojar

• M.Tech
• Staff Associate at Columbia University

Measuring parameters like magnetic field strength and temperature inside a magnet bore is of interest to characterize the system and use that information for downstream image quality improvement or to determine safety thresholds. Multiple commercial measurement systems are available to achieve this goal. However, these systems are often expensive,...

Background Very low‐field MR has emerged as a promising complementary device to high‐field MRI scanners, offering several advantages. One of the key benefits is that very low‐field scanners are generally more portable and affordable to purchase and maintain, making them an attractive option for medical facilities looking to reduce costs. Very low‐f...

The purpose of this study is to demonstrate the first work of T1-based magnetic resonance thermometry using magnetic resonance fingerprinting (dubbed MRFT). We compared temperature estimation of MRFT with proton resonance frequency shift (PRFS) thermometry onex vivobovine muscle. We demonstrated MRFT's feasibility in predicting temperature onex viv...

Purpose: Brain and spinal cord tumors are the second most common cancer in children and account for one out of four cancers diagnosed. However, the long acquisition times associated with acquiring both data types prohibit using quantitative MR (qMR) in pediatric imaging protocols. This study aims to demonstrate the tailored magnetic resonance fing...

Magnetic Resonance Imaging (MR Imaging) is routinely employed in diagnosing Alzheimer's Disease (AD), which accounts for up to 60–80% of dementia cases. However, it is time-consuming, and protocol optimization to accelerate MR Imaging requires local expertise since each pulse sequence involves multiple configurable parameters that need optimization...

Neuroimaging of certain pathologies requires both multi-parametric qualitative and quantitative imaging. The role of the quantitative MRI (qMRI) is well accepted but suffers from long acquisition times leading to patient discomfort, especially in geriatric and pediatric patients. Previous studies show that synthetic MRI can be used in order to redu...

The purpose of this study is to demonstrate the first work of T 1 -based magnetic resonance thermometry using magnetic resonance fingerprinting (dubbed MRFT). We compared temperature estimation of MRFT with proton resonance frequency shift (PRFS) thermometry on ex vivo bovine muscle. We demonstrated MRFT’s feasibility in predicting temperature on e...

Magnetic Resonance Imaging (MRI) is expensive and time-consuming. Protocol optimization to accelerate MRI requires local expertise since each MR sequence involves multiple configurable parameters that need optimization for contrast, acquisition time, and signal-to-noise ratio (SNR). The availability and access to technical training are limited in u...

Purpose Brain and spinal cord tumors are the second most common cancer in children and account for one out of four cancers diagnosed. However, the long acquisition times associated with acquiring both data types prohibit using quantitative MR (qMR) in pediatric imaging protocols. This study aims to demonstrate the tailored magnetic resonance finger...

Neuroimaging of certain pathologies requires both multi-parametric qualitative and quantitative imaging. The role of the quantitative MRI (qMRI) is well accepted but suffers from long acquisition times leading to patient discomfort, especially in geriatric and pediatric patients. Previous studies show that synthetic MRI can be used in order to redu...

Denoising is an alternative for enhancing signal-to-noise ratio in high b-value diffusion imaging instead of prolonged acquisition time. We experimented with a deep learning-based denoising method on prospective high b-value DWI and visualized the impact of denoising using fractional anisotropy(FA) maps. The experiment was repeated for three differ...

Purpose The goals of this study include: (a) generating tailored magnetic resonance fingerprinting (TMRF) based non‐synthetic imaging; (b) assessing the repeatability of TMRF and deep learning‐based mapping of in vitro ISMRM/NIST phantom and in vivo brain data of healthy human subjects. Methods We have acquired qualitative images obtained from the...

Diffusion-weighted imaging (DWI) allows white matter quantification of the white matter tracts of the brain. However, at a high b-value (≥ 2000 s/mm2), DWI acquisition suffers from noise due to longer acquisition times obscuring white matter interpretation. DWI denoising techniques can be used to acquire high b-value DWI without increasing the numb...

Stroke is a leading cause of death and disability worldwide. The reasons for increased stroke burden in developing countries are inadequately controlled risk factors resulting from poor public awareness and inadequate infrastructure. Computed tomography and MRI are common neuroimaging modalities used to assess stroke with diffusion‐weighted MRI, in...

Synopsis: DWI MRI is a well established method for stroke imaging, within the critical operating window of approximately four to six hours. This requires an accessible, portable and cost effective MR solution typically achieved at very low magnetic fields. In this work, simulation of low b value DWI images at 10mT has been performed in comparison w...

Open source diffusion acquisition software

Magnetic resonance imaging is a well-established method for diagnostics and/or prognostics of various pathological conditions. Cartesian k-space trajectory-based acquisition is the popular choice in clinical magnetic resonance imaging, owing to its simple acquisition, reconstruction schemes, and well-understood artifacts. However, non-Cartesian tra...

The proposed work involves an exclusive study on the synthesis protocol, crystal structure analysis, and imaging contrast features of unique lanthanide phosphates (LnPO4). XRD and Raman spectra affirmed the ability of the proposed synthesis technique to achieve unique LnPO4 devoid of impurities. The crystal structure analysis confirms the P121/c1 s...

Purpose: To provide a single open-source platform for comprehensive MR algorithm development inclusive of simulations, pulse sequence design and deployment, reconstruction, and image analysis. Methods: We integrated the "Pulseq" platform for vendor-independent pulse programming with Graphical Programming Interface (GPI), a scientific development...

A series of Gd(3+) dopings in zirconia-toughened alumina (ZTA) systems were undertaken to explore the resultant structural, morphological, hydrothermal aging, and mechanical behavior and imaging contrast abilities. The results from the characterization techniques demonstrate the significance of Gd(3+) in preserving the structural stability of ZTA s...

This work proposes chemically synthesized Gd doped ZnS nanoparticles based system for potential use as contrast enhancing agent for both optical fluorescence imaging and magnetic resonance imaging. Two different Gd doped ZnS nanoparticle systems were synthesized. These systems were (i) graphene oxide-Zn1-xGdxS (x=0.1, 0.2 and 0.3) nanoparticle comp...

A series of Gd3 + and Dy3 + co-substituted β-Ca3(PO4)2 as a multifunctional bio-probe has been developed. Structural analysis revealed preferential occupancy of both Gd3 + and Dy3 + at Ca2 +(1), Ca2 +(2) and Ca2 +(3) sites of β-Ca3(PO4)2 and ~ 4.20 mol.% has been determined as the substitution limit for co-substitutions with individual contribution...

A series of Dysprosium (Dy3+) doped β-Tricalcium phosphate [β-TCP, β-Ca3(PO4)2] were developed for applications in magnetic resonance imaging (MRI) and computed tomography (CT). Characterization studies confirmed the Dy3+ occupancy at Ca2+(1), Ca2+(2), and Ca2+(3) lattice sites of β-Ca3(PO4)2 and its substitution limit was determined as 4.35 mol%....

To compensate the limitations of bone tissue magnetic resonance imaging (MRI), a series of gadolinium (Gd(3+) ) substituted β-Tricalcium phosphate [β-TCP, β-Ca3 (PO4 )2 ] were developed. All the powders were characterized using XRD, Raman spectroscopy, Rietveld refinement of the XRD data and the studies confirmed the Gd(3+) occupancy at Ca(2+) (1),...

Graphene oxide-CoFe2O4 nanoparticle composites were synthesized using a two step synthesis method in which graphene oxide was initially synthesized followed by precipitation of CoFe2O4 nanoparticles in a reaction mixture containing graphene oxide. Samples were extracted from the reaction mixture at different times at 80˚C. All the extracted samples...

K-space trajectories such as cartesian, radial, spiral are not optimal for traversing arbitrary k-space shapes. GO-Active is a novel acquisition technique which is a combination of active contour and convex optimization where active contour was used to obtain arbitrary k-space trajectory and convex optimization was employed to optimize the gradient...

In dynamic scans, the significant values of k-space dependent on the shape of the organ which leads to arbitrary k-space trajectories. Gradient optimization for arbitrary k-space trajectory using active contour is a new acquisition technique that has been applied on six DCE breast data. The arbitrary k-space trajectory was obtained by active contou...

The potential of graphene oxide–Fe3O4 nanoparticle (GO-Fe3O4) composite as an image contrast enhancing material in magnetic resonance imaging has been investigated. Proton relaxivity values were obtained in three different homogeneous dispersions of GO-Fe3O4 composites synthesized by precipitating Fe3O4 nanoparticles in three different reaction mix...

Purpose: Diffusion Weighted Magnetic Resonance imaging (DW-MRI) provides the microstructural data of human brain. However, the acquisition of multiple b values for computation of Apparent Diffusion Coefficient (ADC) and Diffusion Tensor Imaging (DTI) maps are time consuming. There are several methods to reduce the scan time such as optimal gradient...

Dynamic MRI methods such as cardiac MRI require fast acquisition of data for increased temporal resolution to avoid artifacts and image the functions. The Region of Interest (ROI) is typically smaller compared to the entire image and the Field of View (FOV) cannot be reduced beyond a certain extent to view the ROI distinctly. The ROI selected image...

Production of bio-compatible contrast agent materials to enhance the sensitivity of the magnetic resonance imaging (MRI) technique is a highly active area in MRI related research. This work illustrates the potential of a new material: graphene oxide-gadolinium (III) oxide nanoparticle (GO-Gd2O3) composite in yielding both transverse (16.3mM-1 s-1)...

This work investigates the potential of graphene oxide-cobalt ferrite nanoparticle (GO-CoFe2O4) composite as image contrast enhancing material in Magnetic Resonance Imaging (MRI). In the preset work, GO-CoFe2O4 composites were produced by a two-step synthesis process. In the first step, graphene oxide (GO) was synthesized, and in the second step Co...

Purpose: Prenatal survival critically depends on a sufficiently sized and functionally well-developed brain and cardiopulmonary system [1]. Computation of fetal brain volume can be used as a biometric measure to monitor the fetal development for diagnosis and/or prognosis of fetal pathologies. The diseases related to abnormal development of the bra...

BACKGROUND Previous work performed on fetal MRI use apriori information that is typically dependent on contrast [1]. An algorithm, which is not restricted by such dependence would enable seamless application of segmentation approaches for different MR contrast types. EVALUATION A database containing 6 MRI volumes of fetuses was used for this stud...