Artem Mikheev

NYU Langone Medical Center | NYUMC · Department of Radiology

We have implemented a method (BiCal) for correction of image nonuniformity. Using objective criteria we have compared BiCal to widely used N4 algorithm in several challenging clinical MRI applications. There was a significant advantage of BiCal over N4 for 7T brain MRI and for accelerated radial GRASP of the abdomen. The performance of BiCal and N4...

Background Monoexponential apparent diffusion coefficient (ADC) and biexponential intravoxel incoherent motion (IVIM) analysis of diffusion‐weighted imaging is helpful in the characterization of breast tumors. However, repeatability/reproducibility studies across scanners and across sites are scarce. Purpose To evaluate the repeatability and repro...

Purpose: Diffusion-weighted imaging (DWI) of the abdomen has increased dramatically for both research and clinical purposes. Motion and static field inhomogeneity related challenges limit image quality of abdominopelvic imaging with the most conventional echo-planar imaging (EPI) pulse sequence. While reversed phase encoded imaging is increasingly...

Background: Renal diffusion-weighted imaging (DWI) involves microstructure and microcirculation, quantified with diffusion tensor imaging (DTI), intravoxel incoherent motion (IVIM), and hybrid models. A better understanding of their contrast may increase specificity. Purpose: To measure modulation of DWI with cardiac phase and flow-compensated (...

Given the central role of interstitial fibrosis in disease progression in chronic kidney disease (CKD), a role for diffusion-weighted MRI has been pursued. We evaluated the feasibility and preliminary efficacy of using radiomic features to phenotype apparent diffusion coefficient (ADC) maps and hence to the clinical classification(s) of the partici...

Purpose To assess prognostic value of body composition parameters measured at CT to predict risk of hospitalization in patients with COVID-19 infection. Methods 177 patients with SARS-CoV-2 infection and with abdominopelvic CT were included in this retrospective IRB approved two-institution study. Patients were stratified based on disease severity...

Objective: Implement T1 mapping workflow Develop new motion correction (MC) method Test workflow in subjects with early OA and normal controls (NC) Hypothesis: Motion correction reduces variability of T1 values

PurposeTo assess visceral (VAT), subcutaneous (SAT), and total adipose tissue (TAT) estimates at abdominopelvic CT in COVID-19 patients with different severity, and analyze Body Mass Index (BMI) and CT estimates of fat content in patients requiring hospitalization.Methods In this retrospective IRB approved HIPPA compliant study, 51 patients with SA...

In this study, we investigate the feasibility of using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI), diffusion weighted imaging (DWI), and dynamic positron emission tomography (PET) for detection of metastatic lymph nodes in head and neck squamous cell carcinoma (HNSCC) cases. Twenty HNSCC patients scheduled for lymph node dissect...

Rationale and objectives: Periventricular and deep white matter hyperintensities (WMHs) in the elderly have been reported with distinctive roles in the progression of cognitive decline and dementia. However, the definition of these two subregions of WMHs is arbitrary and varies across studies. Here, we evaluate three partition methods for WMH subr...

Efficient, reproducible and accurate corticomedullary renal segmentation is challenging but important for MR renography and disease monitoring. We assessed segmentation time, reproducibility and accuracy of a virtually automated (VA) approach (<5 second user interaction), compared to gold standard (GS) manual segmentation. Segmentation time per sub...

Fractional anisotropy (FA) and mean diffusivity (MD) derived from diffusion tensor imaging (DTI) are promising for assessing subclinical changes in diabetic kidney disease (DKD). However, renal echo planar DTI can be challenging due to susceptibility artefacts, which can be mitigated by a small field of view (FOV) 2D spatially selective RF excitati...

In patients with mild cognitive impairment from ADNI MRI database, joint analyses of FLAIR and diffusion-tensor MRI (DTI) find significant positive correlation between periventricular white matter lesion (PVWML) and ventricle volumes; and negative correlation between PVWML and grey matter thickness of four cortical regions. Furthermore, significant...

MRI is an attractive modality for monitoring dynamic lung function since it does not expose patients to ionizing radiation. In this study, a method to automatically segment the right and left lungs using XD-GRASP MRI was developed. The accuracy of our segmentation algorithm was assessed by comparing the automated segmentation results to manual segm...

Purpose To undertake an early proof of concept study on a novel, semi‐automated texture‐based scoring system in order to enhance the association between MRI lesions and clinically significant cancer. Patients and methods With ethics approval, 536 imaging volumes were generated from 20 consecutive patients who underwent mpMRI at time of biopsy. Vol...

We analyze the accuracy of atlas-based cartilage segmentation from isotropic T1ρ MRI and compare it to semi-automated "seed and blanket" method and manual segmentation (ground truth). Reference 3D cartilage masks were taken as the consensus of two human experts. For patella, our implementation of template matching yielded the root mean square volum...

Background: Diffusion-weighted imaging (DWI) provides insight into the pathophysiology underlying renal dysfunction. Variants of DWI include intravoxel incoherent motion (IVIM), which differentiates between microstructural diffusion and vascular or tubular flow, and diffusion tensor imaging (DTI), which quantifies diffusion directionality. Purpos...

Background: Potential clinical implications of the level of background parenchymal enhancement (BPE) on breast MRI are increasing. Currently, BPE is typically evaluated subjectively. Tests of concordance between subjective BPE assessment and computer-assisted quantified BPE have not been reported. Purpose or hypothesis: To compare subjective rad...

Rationale and objectives: This study aimed to assess a novel method of three-dimensional (3D) co-registration of prostate magnetic resonance imaging (MRI) examinations performed before and after prostate cancer focal therapy. Materials and methods: We developed a software platform for automatic 3D deformable co-registration of prostate MRI at di...

Breast density, defined as fraction of fibroglandular tissue (FGT), and post-contrast FGT enhancement (background parenchymal enhancement) are considered cancer risk factors. These MRI measures are recommended for radiologic reports and are promising cancer biomarkers. There is a general agreement that isolating the breasts from the chest wall (CW)...

Purpose: To evaluate clinical applicability of fibroglandular tissue (FGT) segmentation on routine T1 weighted breast MRI and compare FGT quantification with radiologist assessment. Methods: FGT was segmented on 232 breasts and quantified, and was assessed qualitatively by four breast imagers. Results: FGT segmentation was successful in all 23...

Purpose: Diffusion-weighted imaging (DWI) and (18) F-fluorodeoxyglucose-positron emission tomography ((18) F-FDG-PET) independently correlate with malignancy in breast cancer, but the relationship between their structural and metabolic metrics is not completely understood. This study spatially correlates diffusion, perfusion, and glucose avidity i...

PET imaging produces quantitative images of radioactivity concentration over time. Radiotracer uptake depends upon a number of factors, for example regional blood flow, capillary permeability, nonspecific binding, available receptor concentration. Dynamic imaging of PET data allows the application of compartment models to extract parameters related...

Mapping mouse brain with atlas for dynamic microPET studies

A semi-automatic renal segmentation technique for non-contrast T1-weighted MR images was developed. Renal segmentation and volumetric analysis was tested in ten healthy volunteers and ten Type I diabetic patients. We found that this segmentation tool is fast, reliable, and requires minimal user interaction. Upon further validation, this method has...

Objective: The aim of this study was to validate computed tomography (CT)-based longitudinal markers of the progression of Alzheimer disease (AD). Materials and methods: We retrospectively studied 33 AD patients and 39 nondemented patients with other neurological illnesses (non-AD) having 4 to 12 CT examinations of the head, with over a mean (SD...

Purpose To identify the ability of computer-derived three-dimensional (3D) computed tomographic (CT) segmentation techniques to help differentiate lung adenocarcinoma subtypes. Materials and Methods This study had institutional research board approval and was HIPAA compliant. Pathologically classified resected lung adenocarcinomas (n = 23) with thi...

Dynamic contrast enhanced (DCE) MRI has emerged as a reliable and diagnostically useful functional imaging technique. DCE protocol typically lasts 3-15 minutes and results in a time series of N volumes. For automated analysis, it is important that volumes acquired at different times be spatially coregistered. We have recently introduced a novel 4D,...

Objective: To investigate the precision and accuracy of a new semi-automated method for kidney segmentation from single-breath-hold non-contrast MRI. Materials and methods: The user draws approximate kidney contours on every tenth slice, focusing on separating adjacent organs from the kidney. The program then performs a sequence of fully automat...

Multiple cross-sectional MRI and pathology studies suggest that brain atrophy rates accelerate after the 7th decade, even for cognitively normal individuals. Unfortunately, there are no longitudinal MRI studies to demonstrate such acceleration, indicating the lack of precision of current methodology. Even for Alzheimer's disease patients, demonstra...

The goal of the study was to investigate the use of high-resolution, MR-derived arterial input functions (AIFs) for improving the estimation of tracer kinetic parameters on human brain tumors during dynamic FDG injection without direct arterial sampling. Dynamic PET and MR data was acquired simultaneously during FDG injection. Tracer kinetic parame...

In this study, we assess the agreement between quantitative imaging parameters derived from dynamic contrast enhanced (DCE) MRI and mean vascular density and percent fibrosis in 15 participants with pancreatic cancer.Spiral k-space 3D T1w GRE was used quantitatively in DCE-MRI permitting whole liver/pancreas coverage with sub 3 second temporal reso...

Purpose: To determine if brain atrophy can be calculated by performing volumetric analysis on conventional computed tomography (CT) scans in spite of relatively low contrast for this modality. Materials & Method: CTs for 73 patients from the local Veteran Affairs database were selected. Exclusion criteria: AD, NPH, tumor, and alcohol abuse. Protoco...

To compare boundaries of prostate tumors on MRI and histologic assessment from radical prostatectomy (RP) using detailed software-assisted co-registration, in order to define an optimal treatment margin to achieve complete tumor destruction during image-guided focal ablation. 33 patients who underwent 3T MRI before RP were included. A radiologist t...

Object: Automated eye movement tracking may provide clues to nervous system function at many levels. Spatial calibration of the eye tracking device requires the subject to have relatively intact ocular motility that implies function of cranial nerves (CNs) III (oculomotor), IV (trochlear), and VI (abducent) and their associated nuclei, along with...

Introduction: Osteoporosis is a disease of weak bone. Our goal was to determine the measurement reproducibility of magnetic resonance assessment of proximal femur strength. Methods: This study had institutional review board approval, and written informed consent was obtained from all subjects. We obtained images of proximal femur microarchitectu...

Objective: The purpose of this study was to estimate perfusion metrics in healthy and cirrhotic liver with pharmacokinetic modeling of high-temporal resolution reconstruction of continuously acquired free-breathing gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced acquisition in patients undergoing clinically indicated liver mag...

Purpose: To evaluate the precision of measures of bone volume and bone volume fraction derived from high-resolution 3T MRI of proximal femur bone microarchitecture using non-uniformity correction. Methods: This HIPAA compliant, institutional review board approved study was conducted on six volunteers (mean age 56 ± 13 years), and written informe...

PurposeWe used a combined intravoxel incoherent motion–diffusion tensor imaging (IVIM-DTI) methodology to distinguish structural from flow effects on renal diffusion anisotropy.Methods Eight volunteers were examined with IVIM-DTI at 3T with 20 diffusion directions and 10 b-values. Mean diffusivity (MD) and fractional anisotropy (FA) from DTI analys...

The precision, accuracy, and efficiency of a novel semi-automated renal segmentation technique for volumetric interpolated breath-hold sequence (VIBE) MRI sequences was analyzed using 7 clinical datasets (14 kidneys). Two observers performed whole-kidney segmentation using EdgeWave segmentation software based on constrained morphological growth. Gr...

To assess a novel method of three-dimensional (3D) co-registration of prostate cancer digital histology and in-vivo multiparametric magnetic resonance imaging (mpMRI) image sets for clinical usefulness. A software platform was developed to achieve 3D co-registration. This software was prospectively applied to three patients who underwent radical pr...

A logic arrangement, system and method for segmentation using magnetic resonance imaging (“MRI”) are provided. For example, as an end product, an image associated with at least one portion of an anatomical structure is generated. In particular, first data associated with the at least one portion of the anatomical structure is received. Second data...

MR signal intensity, especially at high field strength, is affected by inhomogeneity, or shading artifacts, manifested as a smooth spatially varying signal intensity distortions. Correction of this effect is the key to successful implementation of all MR image analyses, including segmentation, registration and functional modeling of dynamic data. W...

To examine the effects of image registration and segmentation error on the accuracy of renal functional parameter estimates as measured with dynamic Gd-enhanced MRI (Gd-MRI). Following intravenous injection of Gd, the change in tracer concentration in renal tissue compartments is monitored over time for assessment of renal function. Image registrat...

Diffusion weighted (DW) imaging is a promising imaging technique for the functional assessment of kidneys. Diffusion-tensor (DT) imaging uses multiple diffusion sensitizing directions to evaluate anisotropic microstructure. Microstructure is a key factor in renal physiology, where cortex contains randomly oriented structures, while medulla holds mo...

MR signal intensity at ultra-high field strength is affected by strong non-uniformity artefacts, attributed to inhomogeneous RF fields, inhomogeneous reception sensitivity and patient’s influence on the magnetic and electric field [1]. Correction of this effect is the key to successful implementation of all MR image analyses, including segmentation...

PURPOSE To validate 3D computer-assisted analysis of lung adenocarcinomas (AdCa) on chest CT by (1) establishing the correlation of the proportion of solid component (%S) with IASLC pathologic classification and (2) assessing interobserver agreement on measured parameters METHOD AND MATERIALS Chest CTs (high-frequency kernel, 1 mm sections) of 30...

To validate a new method to analyze delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) measurements in the hip for early assessment of cartilage defects in femoroacetabular impingement (FAI). We performed a retrospective review of 10 hips in 10 FAI patients, who underwent hip arthroscopy. T1-weighted images and dGEMRIC T(...

Objective: To test that cerebral atrophy is associated with increased risk for development of chronic subdural haematoma (cSDH), this study performed volumetric analysis of computed tomography (CT) brain scans from patients who were diagnosed with cSDH on subsequent CT scans and their age-matched controls. Methods: Volumetric analysis was perfor...

A key prerequisite for analysis of MR renography (MRR) data is the ability to segment MRI images. We have developed and validated a new semi-automated renal segmentation technique based on edge-constrained region growing. The segmentation error is 7.6 ± 6.5 cm3 and the interobserver disparity 5.4 ± 4.5 cm3, a significant improvement over graph-cut...

We used a combined IVIM-DTI methodology to resolve the ambiguity of renal diffusion anisotropy by distinguishing structural from flow effects. We observe a significantly higher perfusion-fraction (fp) of the cortex than medulla, contrary to previous studies finding comparable fp in both tissues. Higher medullary FA at the low b-value range and high...

To assess the reproducibility and the distribution of intravoxel incoherent motion (IVIM) and diffusion-tensor (DT) imaging parameters in healthy renal cortex and medulla at baseline and after hydration or furosemide challenges. Using an institutional review board-approved HIPAA-compliant protocol with written informed consent, IVIM and DT imaging...

Multi-parametric MRI is emerging as a promising method for prostate cancer diagnosis. prognosis and treatment planning. However, the localization of in-vivo detected lesions and pathologic sites of cancer remains a significant challenge. To overcome this limitation we have developed and tested a system for co-registration of in-vivo MRI, ex-vivo MR...

Early detection of cartilage degeneration in the hip may help prevent onset and progression of osteoarthritis in young patients with femoroacetabular impingement. Delayed gadolinium-enhanced MRI of cartilage is sensitive to cartilage glycosaminoglycan loss and could serve as a diagnostic tool for early cartilage degeneration. We propose a new high...

Simple coregistration algorithms do not work well for DCE images because of the change in intensity due to the uptake and washout of contrast agent. We have implemented several coregistration algorithms and tested them in the setting of functional exams of the kidney. The variants differ in sequencing of coregistration steps and in the way the orga...

Dynamic contrast-enhanced (DCE) MRI has shown promise for discrimination of prostate cancer from normal prostatic tissue. We compare three published methods of DCE analysis: maximum wash-in rate of contrast, two-compartment Tofts model, and distributed parameters model (adiabatic approximation to tissue homogeneity, AATH model), and assess their ab...

To validate Bridge Burner, a new brain segmentation algorithm based on thresholding, connectivity, surface detection, and a new operator of constrained growing. T1-weighted MR images were selected at random from three previous neuroimaging studies to represent a spectrum of system manufacturers, pulse sequences, subject ages, genders, and neurologi...

Modeling of the perfusion using dynamic contrast-enhanced (DCE) imaging based on convolution models is gaining increasing attention. The time activity curve of ith voxel is sampled at predefined time intervals, yielding a contrast concentration Ci(t) evaluated at discrete times t=t1…tNT. Perfusion model is then specified to express Ci(t) as the con...

We used dynamic contrast-enhanced MRI in 24 patients including 16 with hepatocellular carcinoma (HCC) using a 3D GRE sequence with a temporal resolution of 3 to 5 sec. Perfusion metrics of HCC were quantified using time concentration curves and a dual input single compartmental model, showing significantly elevated arterial flow and decreased porta...

trans values, the sensitivity and specificity gave two significant figures, 0.90 and 0.68, respectively, and 0.73 and 0.67 for discrimination by ve. The area under the ROC curves for K trans was 0.88 and 0.78 for ve (Fig. 2). Discussion The parameters of the tracer kinetic model, K trans and ve, are significantly higher in tumor than in normal tiss...

Perfusion-weighted imaging (PWI) has the potential to detect and characterize the global and regional perfusional changes from these alterations (1-3). However, data analysis is limited by complicated post-processing time and misregistration artifacts caused by breathing. Our purpose was to develop an automated voxel-based analysis technique to pro...

The application of MRI for pulmonary imaging has come late in comparison to other regions of the body. This is due to the low proton density in the lung parenchyma and susceptibility induced static field inhomogeneities in the chest. Due to the introduction of hyperpolarized noble gases, MRI of the lungs has attracted increasing interest. Current m...

PURPOSE Since the discomfort associated with bowel cleansing reduces patient acceptance of CT colonography (CTC), we evaluated the feasibility of an automated technique to remove tagged fecal material (FM) from CTC data. METHOD AND MATERIALS We performed CTC in the absence of bowel cleansing, one day after the ingestion of 20 ml of a 40% barium su...

A system and process for improving image quality is described. The process uses an edge map to smooth colors based on at least one of how close a pixel is to an edge and the strength of the edge.

Online access to complex compound documents with client side search and browsing capability is one of the key requirements of effective content management. “DjVu” (Déjà Vu) is a highly efficient document image compression methodology, a file format, and a delivery platform that, when considered together, has shown to effectively address these issue...