%0 Conference Proceedings
%A Bebek, O.
%A Hwang, M. J.
%A Fei, B.
%A Cavusoglu, M.
%D 2008
%T Design of a small animal biopsy robot.
%B Conf Proc IEEE Eng Med Biol Soc.
%P 5601-4
%! Design of a small animal biopsy robot.
%@ 1557-170X
%R 10.1109/IEMBS.2008.4650484
%2 PMC2796956
%M 19163987
%K Biopsy
Equipment Design
Equipment Failure Analysis
Needles
Reproducibility of Results
Robotics
Sensitivity and Specificity
Surgery, Computer-Assisted
%X Small animals are widely used in biomedical research studies. They have compact anatomy and small organs. Therefore it is difficult to perceive tumors or cells and perform biopsies manually. Robotics technology offers a convenient and reliable solution for accurate needle insertion. In this paper, a novel 5 degrees of freedom (DOF) robot design for inserting needles into small animal subjects is proposed. The design has a compact size, is light weight, and has high resolution. Parallel mechanisms are used in the design for stable and reliable operation. The proposed robot has two gimbal joints that carry the needle mechanism. The robot can realize dexterous alignment of the needle before insertion.
%U http://www.ncbi.nlm.nih.gov/pubmed/19163987
%+ Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, Ohio, 44106, USA. oxb6@case.edu
%G eng



%0 Journal Article
%A Bogie, K.
%A Wang, X.
%A Fei, B.
%A Sun, J.
%D 2008
%T New technique for real-time interface pressure analysis: getting more out of large image data sets.
%J J Rehabil Res Dev.
%V 45
%N 4
%P 523-35
%! New technique for real-time interface pressure analysis: getting more out of large image data sets.
%@ 1938-1352
%2 PMC2729147
%M 18712638
%K Algorithms
Buttocks
Electric Stimulation
Electric Stimulation Therapy
Humans
Imaging, Three-Dimensional
Longitudinal Studies
Pressure
Pressure Ulcer
Risk Factors
Time Factors
Wheelchairs
%X Recent technological improvements have led to increasing clinical use of interface pressure mapping for seating pressure evaluation, which often requires repeated assessments. However, clinical conditions cannot be controlled as closely as research settings, thereby creating challenges to statistical analysis of data. A multistage longitudinal analysis and self-registration (LASR) technique is introduced that emphasizes real-time interface pressure image analysis in three dimensions. Suitable for use in clinical settings, LASR is composed of several modern statistical components, including a segmentation method. The robustness of our segmentation method is also shown. Application of LASR to analysis of data from neuromuscular electrical stimulation (NMES) experiments confirms that NMES improves static seating pressure distributions in the sacral-ischial region over time. Dynamic NMES also improves weight-shifting over time. These changes may reduce the risk of pressure ulcer development.
%U http://www.ncbi.nlm.nih.gov/pubmed/18712638
%+ Cleveland Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA. kmb3@case.edu
%G eng



%0 Journal Article
%A Chen, X.
%A Gilkeson, R. C.
%A Fei, B.
%D 2007
%T Automatic 3D-to-2D registration for CT and dual-energy digital radiography for calcification detection.
%J Med Phys
%V 34
%N 12
%P 4934-43
%8 Dec
%! Automatic 3D-to-2D registration for CT and dual-energy digital radiography for calcification detection.
%@ 0094-2405
%2 PMC2743028
%M 18196818
%K Calcinosis
Clinical Medicine
Coronary Artery Disease
Heart
Humans
Imaging, Three-Dimensional
Models, Theoretical
Phantoms, Imaging
Radiography, Dual-Energy Scanned Projection
Tomography, X-Ray Computed
%X We are investigating three-dimensional (3D) to two-dimensional (2D) registration methods for computed tomography (CT) and dual-energy digital radiography (DEDR). CT is an established tool for the detection of cardiac calcification. DEDR could be a cost-effective alternative screening tool. In order to utilize CT as the "gold standard" to evaluate the capability of DEDR images for the detection and localization of calcium, we developed an automatic, intensity-based 3D-to-2D registration method for 3D CT volumes and 2D DEDR images. To generate digitally reconstructed radiography (DRR) from the CT volumes, we developed several projection algorithms using the fast shear-warp method. In particular, we created a Gaussian-weighted projection for this application. We used normalized mutual information (NMI) as the similarity measurement. Simulated projection images from CT values were fused with the corresponding DEDR images to evaluate the localization of cardiac calcification. The registration method was evaluated by digital phantoms, physical phantoms, and clinical data sets. The results from the digital phantoms show that the success rate is 100% with a translation difference of less than 0.8 mm and a rotation difference of less than 0.2 degrees. For physical phantom images, the registration accuracy is 0.43 +/- 0.24 mm. Color overlay and 3D visualization of clinical images show that the two images registered well. The NMI values between the DRR and DEDR images improved from 0.21 +/- 0.03 before registration to 0.25 +/- 0.03 after registration. Registration errors measured from anatomic markers decreased from 27.6 +/- 13.6 mm before registration to 2.5 +/- 0.5 mm after registration. Our results show that the automatic 3D-to-2D registration is accurate and robust. This technique can provide a useful tool for correlating DEDR with CT images for screening coronary artery calcification.
%U http://www.ncbi.nlm.nih.gov/pubmed/18196818
%+ Department of Radiology, Case Western Reserve University, Cleveland, Ohio 44106, USA.
%G eng



%0 Journal Article
%A Cheng, Y.
%A C Samia, A.
%A Meyers, J. D.
%A Panagopoulos, I.
%A Fei, B.
%A Burda, C.
%D 2008
%T Highly efficient drug delivery with gold nanoparticle vectors for in vivo photodynamic therapy of cancer.
%J J Am Chem Soc
%V 130
%N 32
%P 10643-7
%8 Aug
%! Highly efficient drug delivery with gold nanoparticle vectors for in vivo photodynamic therapy of cancer.
%@ 1520-5126
%R 10.1021/ja801631c
%2 PMC2719258
%M 18642918
%K Animals
Drug Delivery Systems
Gold
Indoles
Metal Nanoparticles
Mice
Mice, Nude
Neoplasms
Photochemotherapy
Polyethylene Glycols
Radiation-Sensitizing Agents
Singlet Oxygen
Spectrometry, Fluorescence
Spectrophotometry, Ultraviolet
%X A highly efficient drug vector for photodynamic therapy (PDT) drug delivery was developed by synthesizing PEGylated gold nanoparticle conjugates, which act as a water-soluble and biocompatible "cage" that allows delivery of a hydrophobic drug to its site of PDT action. The dynamics of drug release in vitro in a two-phase solution system and in vivo in cancer-bearing mice indicates that the process of drug delivery is highly efficient, and passive targeting prefers the tumor site. With the Au NP-Pc 4 conjugates, the drug delivery time required for PDT has been greatly reduced to less than 2 h, compared to 2 days for the free drug.
%U http://www.ncbi.nlm.nih.gov/pubmed/18642918
%+ Center for Chemical Dynamics and Nanomaterials Research, Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA.
%G eng



%0 Journal Article
%A Fei, B.
%A Chen, X.
%A Wang, H.
%A Sabol, J. M.
%A DuPont, E.
%A Gilkeson, R. C.
%D 2006
%T Automatic registration of CT volumes and dual-energy digital radiography for detection of cardiac and lung diseases.
%J Conf Proc IEEE Eng Med Biol Soc.
%V 1
%P 1976-9
%! Automatic registration of CT volumes and dual-energy digital radiography for detection of cardiac and lung diseases.
%@ 1557-170X
%R 10.1109/IEMBS.2006.259888
%2 PMC2743908
%M 17945687
%K Algorithms
Artificial Intelligence
Calcinosis
Coronary Angiography
Coronary Artery Disease
Humans
Imaging, Three-Dimensional
Lung Diseases
Radiographic Image Enhancement
Radiography, Dual-Energy Scanned Projection
Reproducibility of Results
Sensitivity and Specificity
Subtraction Technique
Tomography, X-Ray Computed
%X We are investigating image processing and analysis techniques to improve the ability of dual-energy digital radiography (DR) for the detection of cardiac calcification. Computed tomography (CT) is an established tool for the diagnosis of coronary artery diseases. Dual-energy digital radiography could be a cost-effective alternative. In this study, we use three-dimensional (3D) CT images as the "gold standard" to evaluate the DR X-ray images for calcification detection. To this purpose, we developed an automatic registration method for 3D CT volumes and two-dimensional (2D) X-ray images. We call this 3D-to-2D registration. We first use a 3D CT image volume to simulate X-ray projection images and then register them with X-ray images. The registered CT projection images are then used to aid the interpretation dual-energy X-ray images for the detection of cardiac calcification. We acquired both CT and X-ray images from patients with coronary artery diseases. Experimental results show that the 3D-to-2D registration is accurate and useful for this new application.
%U http://www.ncbi.nlm.nih.gov/pubmed/17945687
%+ Dept. of Radiol. & Biomed. Eng., Case Western Reserve Univ., Cleveland, OH 44106, USA. baowei.fei@case.edu
%G eng



%0 Journal Article
%A Fei, B.
%A Duerk, J. L.
%A Boll, D. T.
%A Lewin, J. S.
%A Wilson, D. L.
%D 2003
%T Slice-to-volume registration and its potential application to interventional MRI-guided radio-frequency thermal ablation of prostate cancer.
%J IEEE Trans Med Imaging
%V 22
%N 4
%P 515-25
%8 Apr
%! Slice-to-volume registration and its potential application to interventional MRI-guided radio-frequency thermal ablation of prostate cancer.
%@ 0278-0062
%R 10.1109/TMI.2003.809078
%M 12774897
%K Algorithms
Artifacts
Catheter Ablation
Computer Simulation
Humans
Imaging, Three-Dimensional
Magnetic Resonance Imaging
Male
Monitoring, Intraoperative
Prostatic Neoplasms
Reproducibility of Results
Sensitivity and Specificity
Subtraction Technique
Surgery, Computer-Assisted
%X In this study, we registered live-time interventional magnetic resonance imaging (iMRI) slices with a previously obtained high-resolution MRI volume that in turn can be registered with a variety of functional images, e.g., PET, SPECT, for tumor targeting. We created and evaluated a slice-to-volume (SV) registration algorithm with special features for its potential use in iMRI-guided radio-frequency (RF) thermal ablation of prostate cancer. The algorithm features included a multiresolution approach, two similarity measures, and automatic restarting to avoid local minima. Imaging experiments were performed on volunteers using a conventional 1.5-T MR scanner and a clinical 0.2-T C-arm iMRI system under realistic conditions. Both high-resolution MR volumes and actual iMRI image slices were acquired from the same volunteers. Actual and simulated iMRI images were used to test the dependence of SV registration on image noise, receive coil inhomogeneity, and RF needle artifacts. To quantitatively assess registration, we calculated the mean voxel displacement over a volume of interest between SV registration and volume-to-volume registration, which was previously shown to be quite accurate. More than 800 registration experiments were performed. For transverse image slices covering the prostate, the SV registration algorithm was 100% successful with an error of <2 mm, and the average and standard deviation was only 0.4 mm +/- 0.2 mm. Visualizations such as combined sector display and contour overlay showed excellent registration of the prostate and other organs throughout the pelvis. Error was greater when an image slice was obtained at other orientations and positions, mostly because of inconsistent image content such as that from variable rectal and bladder filling. These preliminary experiments indicate that MR SV registration is sufficiently accurate to aid image-guided therapy.
%U http://www.ncbi.nlm.nih.gov/pubmed/12774897
%+ Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
%G eng



%0 Journal Article
%A Fei, B.
%A Duerk, J. L.
%A Sodee, D. B.
%A Wilson, D. L.
%D 2005
%T Semiautomatic nonrigid registration for the prostate and pelvic MR volumes.
%J Acad Radiol
%V 12
%N 7
%P 815-24
%8 Jul
%! Semiautomatic nonrigid registration for the prostate and pelvic MR volumes.
%@ 1076-6332
%R S1076-6332(05)00277-1 [pii]

10.1016/j.acra.2005.03.063
%M 16039535
%K Algorithms
Femur
Humans
Imaging, Three-Dimensional
Magnetic Resonance Imaging
Male
Pelvis
Prostatic Neoplasms
%X Three-dimensional (3D) nonrigid image registration for potential applications in prostate cancer treatment and interventional magnetic resonance (iMRI) imaging-guided therapies were investigated.|An almost fully automated 3D nonrigid registration algorithm using mutual information and a thin plate spline (TPS) transformation for MR images of the prostate and pelvis were created and evaluated. In the first step, an automatic rigid body registration with special features was used to capture the global transformation. In the second step, local feature points (FPs) were registered using mutual information. An operator entered only five FPs located at the prostate center, left and right hip joints, and left and right distal femurs. The program automatically determined and optimized other FPs at the external pelvic skin surface and along the femurs. More than 600 control points were used to establish a TPS transformation for deformation of the pelvic region and prostate. Ten volume pairs were acquired from three volunteers in the diagnostic (supine) and treatment positions (supine with legs raised).|Various visualization techniques showed that warping rectified the significant pelvic misalignment by the rigid-body method. Gray-value measures of registration quality, including mutual information, correlation coefficient, and intensity difference, all improved with warping. The distance between prostate 3D centroids was 0.7 +/- 0.2 mm after warping compared with 4.9 +/- 3.4 mm with rigid-body registration.|Semiautomatic nonrigid registration works better than rigid-body registration when patient position is changed greatly between acquisitions. It could be a useful tool for many applications in the management of prostate.
%U http://www.ncbi.nlm.nih.gov/pubmed/16039535
%+ Department of Radiology, Case Western Reserve University and University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, OH 44106, USA. baowei.fei@case.edu
%G eng



%0 Journal Article
%A Fei, B.
%A Duerk, J. L.
%A Wilson, D. L.
%D 2002
%T Automatic 3D registration for interventional MRI-guided treatment of prostate cancer.
%J Comput Aided Surg
%V 7
%N 5
%P 257-67
%! Automatic 3D registration for interventional MRI-guided treatment of prostate cancer.
%@ 1092-9088
%R 10.1002/igs.10052
%M 12582978
%K Algorithms
Computer Simulation
Feasibility Studies
Humans
Imaging, Three-Dimensional
Magnetic Resonance Imaging
Male
Prostatic Neoplasms
Surgical Procedures, Minimally Invasive
%X The goal of this research is to register real-time interventional magnetic resonance imaging (iMRI) slice images with a previously obtained high-resolution MRI image volume, which in turn can be registered with functional images such as those from SPECT. The immediate application is in iMRI-guided treatment of prostate cancer, where additional images are desired to improve tumor targeting. In this article, simulation experiments are performed to demonstrate the feasibility of slice-to-volume registration for this application. We acquired 3D volume images from a 1.5-T MRI system and simulated low-field iMRI image slices by creating thick slices and adding noise. We created a slice-to-volume mutual information registration algorithm with special features to improve robustness. Features included a multiresolution approach, two similarity measures, and automatic restarting to avoid local minima. To assess the quality of registration, we calculated 3D displacements on a voxel-by-voxel basis over a volume of interest between slice-to-volume registration and volume-to-volume registration, which was previously shown to be quite accurate. More than 800 registration experiments were performed on MR images of three volunteers. The slice-to-volume registration algorithm was very robust and accurate for transverse slice images covering the prostate, with a registration error of only 0.4 +/- 0.2 mm. Error was greater at other slice orientations and positions. The automatic slice-to-volume mutual information registration algorithm is robust and probably sufficiently accurate to aid in iMRI-guided treatment of prostate cancer.
%U http://www.ncbi.nlm.nih.gov/pubmed/12582978
%+ Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA.
%G eng



%0 Conference Proceedings
%A Fei, B.
%A Flask, C.
%A Wang, H.
%A Pi, A.
%A Wilson, D.
%A Shillingford, J.
%A Murcia, N.
%A Weimbs, T.
%A Duerk, J.
%D 2005
%T Image Segmentation, Registration and Visualization of Serial MR Images for Therapeutic Assessment of Polycystic Kidney Disease in Transgenic Mice.
%B Conf Proc IEEE Eng Med Biol Soc.
%V 1
%P 467-9
%! Image Segmentation, Registration and Visualization of Serial MR Images for Therapeutic Assessment of Polycystic Kidney Disease in Transgenic Mice.
%@ 1557-170X
%R 10.1109/IEMBS.2005.1616448
%M 17282217
%X In vivo small animal imaging provides a powerful tool for the study of a variety of diseases. Magnetic resonance imaging (MRI) has become an established technology for the assessment of therapies. In this study, we used high-resolution MRI to evaluate polycystic kidney disease (PKD) in transgenic mice. We used a customized mouse coil to acquire serial MR images from both wide-type and transgenic PKD mice immediately prior to, and 2-week and 4-week after therapy. We developed image segmentation, registration and visualization methods for this novel imaging application. We measured the kidney volumes for each mouse to assess the efficacy of the therapy. The segmentation results show that the kidney volumes are consistent, which are 348.7 ± 19.7 mm<sup>3</sup>for wild-type mice and 756.3 ± 44.1 mm<sup>3</sup>for transgenic mice, respectively. The image analysis methods provide a useful tool for this new application.
%U http://www.ncbi.nlm.nih.gov/pubmed/17282217
%+ Department of Radiology, Case Western Reserve University & University Hospitals of Cleveland, USA.
%G eng



%0 Journal Article
%A Fei, B.
%A Kemper, C.
%A Wilson, D. L.
%D 2003
%T A comparative study of warping and rigid body registration for the prostate and pelvic MR volumes.
%J Comput Med Imaging Graph
%V 27
%N 4
%P 267-81
%8 2003 Jul-Aug
%! A comparative study of warping and rigid body registration for the prostate and pelvic MR volumes.
%@ 0895-6111
%R S0895611102000939 [pii]
%M 12631511
%K Algorithms
Humans
Imaging, Three-Dimensional
Magnetic Resonance Imaging
Male
Models, Statistical
Pelvis
Posture
Prostate
Prostatic Neoplasms
Radiometry
%X A three-dimensional warping registration algorithm was created and compared to rigid body registration of magnetic resonance (MR) pelvic volumes including the prostate. The rigid body registration method combines the advantages of mutual information (MI) and correlation coefficient at different resolutions. Warping registration is based upon independent optimization of many interactively placed control points (CP's) using MI and a thin plate spline transformation. More than 100 registration experiments with 17 MR volume pairs determined the quality of registration under conditions simulating potential interventional MRI-guided treatments of prostate cancer. For image pairs that stress rigid body registration (e.g. supine, the diagnostic position, and legs raised, the treatment position), both visual and numerical evaluation methods showed that warping consistently worked better than rigid body. Experiments showed that approximately 180 strategically placed CP's were sufficiently expressive to capture important features of the deformation.
%U http://www.ncbi.nlm.nih.gov/pubmed/12631511
%+ Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
%G eng



%0 Journal Article
%A Fei, B.
%A Suri, J. S.
%A Wilson, D. L.
%D 2005
%T Three-Dimensional Volume Registration of Carotid MR Images.
%J Stud Health Technol Inform
%V 113
%P 394-411
%! Three-Dimensional Volume Registration of Carotid MR Images.
%@ 0926-9630
%M 15923750
%X This chapter describes automatic three-dimensional registration techniques for magnetic resonance images of carotid vessels. The immediate applications include atherosclerotic plaque characterization and plaque burden quantification vector-based segmentation using dark blood MR images having multiple contrast weightings (proton density (PD), T1, and T2). Another application is the measurement of disease progression and regression with drug trials. A normalized mutual information registration algorithm is applied to compensate movements between image acquisitions. PD, T1, and T2 images were acquired from patients and volunteers and then matched for image analysis. Visualization methods such as contour overlap showed that vessels well aligned after registration. Distance measurements from the landmarks indicated that the registration method worked well with an error of less than 1-mm.
%U http://www.ncbi.nlm.nih.gov/pubmed/15923750
%+ Case Western Reserve University, Cleveland, OH, USA.
%G eng



%0 Journal Article
%A Fei, B.
%A Wang, H.
%A Meyers, J. D.
%A Feyes, D. K.
%A Oleinick, N. L.
%A Duerk, J. L.
%D 2007
%T High-field magnetic resonance imaging of the response of human prostate cancer to Pc 4-based photodynamic therapy in an animal model.
%J Lasers Surg Med
%V 39
%N 9
%P 723-30
%8 Oct
%! High-field magnetic resonance imaging of the response of human prostate cancer to Pc 4-based photodynamic therapy in an animal model.
%@ 0196-8092
%R 10.1002/lsm.20576
%2 PMC2719260
%M 17960753
%K Animals
Humans
Image Processing, Computer-Assisted
Indoles
Magnetic Resonance Imaging
Male
Mice
Mice, Nude
Photochemotherapy
Photosensitizing Agents
Prostatic Neoplasms
Transplantation, Heterologous
%X High-field magnetic resonance imaging (MRI) is an emerging technique that provides a powerful, non-invasive tool for in vivo studies of cancer therapy in animal models. Photodynamic therapy (PDT) is a relatively new treatment modality for prostate cancer, the second leading cause of cancer mortality in American males. The goal of this study was to evaluate the response of human prostate tumor cells growing as xenografts in athymic nude mice to Pc 4-sensitized PDT.|PC-3, a cell line derived from a human prostate malignant tumor, was injected intradermally on the back flanks of athymic nude mice. Two tumors were initiated on each mouse. One was treated and the other served as the control. A second-generation photosensitizing drug Pc 4 (0.6 mg/kg body weight) was delivered to each animal by tail vein injection 48 hours before laser illumination (672 nm, 100 mW/cm(2), 150 J/cm(2)). A dedicated high-field (9.4 T) small-animal MR scanner was used for image acquisitions. A multi-slice multi-echo (MSME) technique, permitting noninvasive in vivo assessment of potential therapeutic effects, was used to measure the T2 values and tumor volumes. Animals were scanned immediately before and after PDT and 24 hours after PDT. T2 values were computed and analyzed for the tumor regions.|For the treated tumors, the T2 values significantly increased (P<0.002) 24 hours after PDT (68.2+/- 8.5 milliseconds), compared to the pre-PDT values (55.8+/-6.6 milliseconds). For the control tumors, there was no significant difference (P = 0.53) between the pre-PDT (52.5+/-6.1 milliseconds) and 24-hour post-PDT (54.3+/-6.4 milliseconds) values. Histologic analysis showed that PDT-treated tumors demonstrated necrosis and inflammation that was not seen in the control.|Changes in tumor T2 values measured by multi-slice multi-echo MR imaging provide an assay that could be useful for clinical monitoring of photodynamic therapy of prostate tumors.
%U http://www.ncbi.nlm.nih.gov/pubmed/17960753
%+ Department of Radiology, Case Western Reserve University & University Hospitals Case Medical Center, Cleveland, Ohio, 44106, USA. Baowei.Fei@case.edu
%G eng



%0 Journal Article
%A Fei, B.
%A Wang, H.
%A Muzic, R. F.
%A Flask, C.
%A Wilson, D. L.
%A Duerk, J. L.
%A Feyes, D. K.
%A Oleinick, N. L.
%D 2006
%T Deformable and rigid registration of MRI and microPET images for photodynamic therapy of cancer in mice.
%J Med Phys
%V 33
%N 3
%P 753-60
%8 Mar
%! Deformable and rigid registration of MRI and microPET images for photodynamic therapy of cancer in mice.
%@ 0094-2405
%M 16878577
%K Animals
Automation
Disease Models, Animal
Fluorodeoxyglucose F18
Image Processing, Computer-Assisted
Imaging, Three-Dimensional
Kidney
Magnetic Resonance Imaging
Mice
Neoplasms
Photochemotherapy
Positron-Emission Tomography
Reproducibility of Results
Sensitivity and Specificity
Time Factors
Urinary Bladder
Whole-Body Counting
%X We are investigating imaging techniques to study the tumor response to photodynamic therapy (PDT). Positron emission tomography (PET) can provide physiological and functional information. High-resolution magnetic resonance imaging (MRI) can provide anatomical and morphological changes. Image registration can combine MRI and PET images for improved tumor monitoring. In this study, we acquired high-resolution MRI and microPET 18F-fluorodeoxyglucose (FDG) images from C3H mice with RIF-1 tumors that were treated with Pc 4-based PDT. We developed two registration methods for this application. For registration of the whole mouse body, we used an automatic three-dimensional, normalized mutual information algorithm. For tumor registration, we developed a finite element model (FEM)-based deformable registration scheme. To assess the quality of whole body registration, we performed slice-by-slice review of both image volumes; manually segmented feature organs, such as the left and right kidneys and the bladder, in each slice; and computed the distance between corresponding centroids. Over 40 volume registration experiments were performed with MRI and microPET images. The distance between corresponding centroids of organs was 1.5 +/- 0.4 mm which is about 2 pixels of microPET images. The mean volume overlap ratios for tumors were 94.7% and 86.3% for the deformable and rigid registration methods, respectively. Registration of high-resolution MRI and microPET images combines anatomical and functional information of the tumors and provides a useful tool for evaluating photodynamic therapy.
%U http://www.ncbi.nlm.nih.gov/pubmed/16878577
%+ Department of Radiology, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio 44106, USA. baowei.fei@case.edu
%G eng



%0 Journal Article
%A Fei, B.
%A Wang, H.
%A Wu, C.
%A Chiu, S. M.
%D 2010
%T Choline PET for monitoring early tumor response to photodynamic therapy.
%J J Nucl Med
%V 51
%N 1
%P 130-8
%8 Jan
%! Choline PET for monitoring early tumor response to photodynamic therapy.
%@ 1535-5667
%R jnumed.109.067579 [pii]

10.2967/jnumed.109.067579
%2 PMC2999358
%M 20008981
%K Algorithms
Animals
Cell Line, Tumor
Cell Survival
Choline
Humans
Image Processing, Computer-Assisted
Indoles
Isotope Labeling
Male
Mice
Mice, Nude
Neoplasm Transplantation
Neoplasms
Photochemotherapy
Photosensitizing Agents
Positron-Emission Tomography
Prostatic Neoplasms
Radiopharmaceuticals
%X Photodynamic therapy (PDT) is a relatively new therapy that has shown promise for treating various cancers in both preclinical and clinical studies. The present study evaluated the potential use of PET with radiolabeled choline to monitor early tumor response to PDT in animal models.|Two human prostate cancer models (PC-3 and CWR22) were studied in athymic nude mice. A second-generation photosensitizer, phthalocyanine 4 (Pc 4), was delivered to each animal by a tail vein injection 48 h before laser illumination. Small-animal PET images with (11)C-choline were acquired before PDT and at 1, 24, and 48 h after PDT. Time-activity curves of (11)C-choline uptake were analyzed before and after PDT. The percentage of the injected dose per gram of tissue was quantified for both treated and control tumors at each time point. In addition, Pc 4-PDT was performed in cell cultures. Cell viability and (11)C-choline uptake in PDT-treated and control cells were measured.|For treated tumors, normalized (11)C-choline uptake decreased significantly 24 and 48 h after PDT, compared with the same tumors before PDT (P < 0.001). For the control tumors, normalized (11)C-choline uptake increased significantly. For mice with CWR22 tumors, the prostate-specific antigen level decreased 24 and 48 h after PDT. Pc 4-PDT in cell culture showed that the treated tumor cells, compared with the control cells, had less than 50% (11)C-choline activity at 5, 30, and 45 min after PDT, whereas the cell viability test showed that the treated cells were viable longer than 7 h after PDT.|PET with (11)C-choline is sensitive for detecting early changes associated with Pc 4-PDT in mouse models of human prostate cancer. Choline PET has the potential to determine whether a PDT-treated tumor responds to treatment within 48 h after therapy.
%U http://www.ncbi.nlm.nih.gov/pubmed/20008981
%+ Department of Radiology, Emory Center for Systems Imaging, Emory University, Atlanta, Georgia 30329, USA. bfei@emory.edu
%G eng



%0 Journal Article
%A Fei, B.
%A Wheaton, A.
%A Lee, Z.
%A Duerk, J. L.
%A Wilson, D. L.
%D 2002
%T Automatic MR volume registration and its evaluation for the pelvis and prostate.
%J Phys Med Biol
%V 47
%N 5
%P 823-38
%8 Mar
%! Automatic MR volume registration and its evaluation for the pelvis and prostate.
%@ 0031-9155
%M 11931473
%K Algorithms
Humans
Magnetic Resonance Imaging
Male
Models, Statistical
Pelvis
Prostate
Prostatic Neoplasms
Radiometry
%X A three-dimensional (3D) mutual information registration method was created and used to register MRI volumes of the pelvis and prostate. It had special features to improve robustness. First, it used a multi-resolution approach and performed registration from low to high resolution. Second, it used two similarity measures, correlation coefficient at lower resolutions and mutual information at full resolution, because of their particular advantages. Third, we created a method to avoid local minima by restarting the registration with randomly perturbed parameters. The criterion for restarting was a correlation coefficient below an empirically determined threshold. Experiments determined the accuracy of registration under conditions found in potential applications in prostate cancer diagnosis, staging, treatment and interventional MRI (iMRI) guided therapies. Images were acquired in the diagnostic (supine) and treatment position (supine with legs raised). Images were also acquired as a function of bladder filling and the time interval between imaging sessions. Overall studies on three patients and three healthy volunteers, when both volumes in a pair were obtained in the diagnostic position under comparable conditions, bony landmarks and prostate 3D centroids were aligned within 1.6 +/- 0.2 mm and 1.4 +/- 0.2 mm, respectively, values only slightly larger than a voxel. Analysis suggests that actual errors are smaller because of the uncertainty in landmark localization and prostate segmentation. Between the diagnostic and treatment positions, bony landmarks continued to register well, but prostate centroids moved towards the posterior 2.8-3.4 mm. Manual cropping to remove voxels in the legs was necessary to register these images. In conclusion, automatic, rigid body registration is probably sufficiently accurate for many applications in prostate cancer. For potential iMRI-guided treatments, the small prostate displacement between the diagnostic and treatment positions can probably be avoided by acquiring volumes in similar positions and by reducing bladder and rectal volumes.
%U http://www.ncbi.nlm.nih.gov/pubmed/11931473
%+ Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
%G eng



%0 Journal Article
%A Haaga, J. R.
%A Exner, A.
%A Fei, B.
%A Seftel, A.
%D 2007
%T Semiquantitative imaging measurement of baseline and vasomodulated normal prostatic blood flow using sildenafil.
%J Int J Impot Res
%V 19
%N 1
%P 110-3
%8 2007 Jan-Feb
%! Semiquantitative imaging measurement of baseline and vasomodulated normal prostatic blood flow using sildenafil.
%@ 0955-9930
%R 3901486 [pii]

10.1038/sj.ijir.3901486
%M 16728965
%K Blood Flow Velocity
Ephedrine
Humans
Magnetic Resonance Imaging
Male
Middle Aged
Phosphodiesterase Inhibitors
Piperazines
Prostate
Purines
Sulfones
Vasoconstrictor Agents
Vasodilator Agents
%X The physiologic variability of blood flow to the prostate has not been studied until this time. We report the vasoactive effects of sildenafil and phenylephrine on blood flow of the normal prostate. Sildenafil increases prostate blood flow by approximately 75% and phenylephrine reduces the flow incrementally. Administration of these drugs with dynamic contrast-enhanced magnetic resonance imaging may improve the diagnosis of cancerous tissue because according to the literature, tumor angiogenic vessels lack the vasoactive physiologic response of the normal tissue.
%U http://www.ncbi.nlm.nih.gov/pubmed/16728965
%+ Department of Radiology, University Hospitals of Cleveland, Cleveland, OH 44106, USA. Haaga@UHRAD.com
%G eng



%0 Journal Article
%A Mafi, J. N.
%A Fei, B.
%A Roble, S.
%A Dota, A.
%A Katrapati, P.
%A Bezerra, H. G.
%A Wang, H.
%A Wang, W.
%A Ciancibello, L.
%A Costa, M.
%A Simon, D. I.
%A Orringer, C. E.
%A Gilkeson, R. C.
%D 2011
%T Assessment of Coronary Artery Calcium Using Dual-Energy Subtraction Digital Radiography.
%J J Digit Imaging
%P [Epub ahead of print]
%8 May
%! Assessment of Coronary Artery Calcium Using Dual-Energy Subtraction Digital Radiography.
%@ 1618-727X
%R 10.1007/s10278-011-9385-y
%M 21557030
%X Cardiovascular disease is the leading cause of global mortality, yet its early detection remains a vexing problem of modern medicine. Although the computed tomography (CT) calcium score predicts cardiovascular risk, relatively high cost ($250-400) and radiation dose (1-3 mSv) limit its universal utility as a screening tool. Dual-energy digital subtraction radiography (DE; <$60, 0.07 mSv) enables detection of calcified structures with high sensitivity. In this pilot study, we examined DE radiography's ability to quantify coronary artery calcification (CAC). We identified 25 patients who underwent non-contrast CT and DE chest imaging performed within 12 months using documented CAC as the major inclusion criteria. A DE calcium score was developed based on pixel intensity multiplied by the area of the calcified plaque. DE scores were plotted against CT scores. Subsequently, a validation cohort of 14 additional patients was independently evaluated to confirm the accuracy and precision of CAC quantification, yielding a total of 39 subjects. Among all subjects (n = 39), the DE score demonstrated a correlation coefficient of 0.87 (p < 0.0001) when compared with the CT score. For the 13 patients with CT scores of <400, the correlation coefficient was -0.26. For the 26 patients with CT scores of ≥400, the correlation coefficient yielded 0.86. This pilot study demonstrates the feasibility of DE radiography to identify patients at the highest cardiovascular risk. DE radiography's accuracy at lower scores remains unclear. Further evaluation of DE radiography as an inexpensive and low-radiation imaging tool to diagnose cardiovascular disease appears warranted.
%U http://www.ncbi.nlm.nih.gov/pubmed/21557030
%+ Case Western Reserve University School of Medicine, 2109 Adelbert Rd., Cleveland, OH, 44106, USA.
%G ENG



%0 Journal Article
%A Wang, H.
%A Fei, B.
%D 2009
%T A modified fuzzy C-means classification method using a multiscale diffusion filtering scheme.
%J Med Image Anal
%V 13
%N 2
%P 193-202
%8 Apr
%! A modified fuzzy C-means classification method using a multiscale diffusion filtering scheme.
%@ 1361-8423
%R S1361-8415(08)00071-6 [pii]

10.1016/j.media.2008.06.014
%2 PMC2817958
%M 18684658
%K Algorithms
Artificial Intelligence
Brain
Cluster Analysis
Diffusion Magnetic Resonance Imaging
Fuzzy Logic
Humans
Image Enhancement
Image Interpretation, Computer-Assisted
Pattern Recognition, Automated
Phantoms, Imaging
Reproducibility of Results
Sensitivity and Specificity
Signal Processing, Computer-Assisted
%X A fully automatic, multiscale fuzzy C-means (MsFCM) classification method for MR images is presented in this paper. We use a diffusion filter to process MR images and to construct a multiscale image series. A multiscale fuzzy C-means classification method is applied along the scales from the coarse to fine levels. The objective function of the conventional fuzzy C-means (FCM) method is modified to allow multiscale classification processing where the result from a coarse scale supervises the classification in the next fine scale. The method is robust for noise and low-contrast MR images because of its multiscale diffusion filtering scheme. The new method was compared with the conventional FCM method and a modified FCM (MFCM) method. Validation studies were performed on synthesized images with various contrasts and on the McGill brain MR image database. Our MsFCM method consistently performed better than the conventional FCM and MFCM methods. The MsFCM method achieved an overlap ratio of greater than 90% as validated by the ground truth. Experiments results on real MR images were given to demonstrate the effectiveness of the proposed method. Our multiscale fuzzy C-means classification method is accurate and robust for various MR images. It can provide a quantitative tool for neuroimaging and other applications.
%U http://www.ncbi.nlm.nih.gov/pubmed/18684658
%+ Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
%G eng



%0 Journal Article
%A Wang, H.
%A Fei, B.
%D 2010
%T Diffusion-weighted MRI for monitoring tumor response to photodynamic therapy.
%J J Magn Reson Imaging
%V 32
%N 2
%P 409-17
%8 Aug
%! Diffusion-weighted MRI for monitoring tumor response to photodynamic therapy.
%@ 1522-2586
%R 10.1002/jmri.22247
%2 PMC3076282
%M 20677270
%K Animals
Cell Line, Tumor
Diffusion
Diffusion Magnetic Resonance Imaging
Humans
Male
Mice
Mice, Nude
Neoplasm Transplantation
Photochemotherapy
Photosensitizing Agents
Prostatic Neoplasms
Treatment Outcome
Tumor Markers, Biological
%X To examine diffusion-weighted MRI (DW-MRI) for assessing the early tumor response to photodynamic therapy (PDT).|Subcutaneous tumor xenografts of human prostate cancer cells (CWR22) were initiated in athymic nude mice. A second-generation photosensitizer, Pc 4, was delivered to each animal by a tail vein injection 48 h before laser illumination. A dedicated high-field (9.4 Tesla) small animal MR scanner was used to acquire diffusion-weighted MR images pre-PDT and 24 h after the treatment. DW-MRI and apparent diffusion coefficients (ADC) were analyzed for 24 treated and 5 control mice with photosensitizer only or laser light only. Tumor size, prostate specific antigen (PSA) level, and tumor histology were obtained at different time points to examine the treatment effect.|Treated mice showed significant tumor size shrinkage and decrease of PSA level within 7 days after the treatment. The average ADC of the 24 treated tumors increased 24 h after PDT (P < 0.001) comparing with pre-PDT. The average ADC was 0.511 +/- 0.119 x 10(-3) mm(2)/s pre-PDT and 0.754 +/- 0.181 x 10(-3) mm(2)/s 24 h after the PDT. There is no significant difference in ADC values pre-PDT and 24 h after PDT in the control tumors (P = 0.20).|The change of tumor ADC values measured by DW-MRI may provide a noninvasive imaging marker for monitoring tumor response to Pc 4-PDT as early as 24 h.
%U http://www.ncbi.nlm.nih.gov/pubmed/20677270
%+ Emory Center for Systems Imaging, Department of Radiology, Emory University, Atlanta, Georgia 30329, USA.
%G eng



%0 Journal Article
%A Yang, X.
%A Fei, B.
%D 2011
%T A multiscale and multiblock fuzzy C-means classification method for brain MR images.
%J Med Phys
%V 38
%N 6
%P 2879-91
%8 Jun
%! A multiscale and multiblock fuzzy C-means classification method for brain MR images.
%@ 0094-2405
%2 PMC3117893
%M 21815363
%K Algorithms
Brain
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
%X Classification of magnetic resonance (MR) images has many clinical and research applications. Because of multiple factors such as noise, intensity inhomogeneity, and partial volume effects, MR image classification can be challenging. Noise in MRI can cause the classified regions to become disconnected. Partial volume effects make the assignment of a single class to one region difficult. Because of intensity inhomogeneity, the intensity of the same tissue can vary with respect to the location of the tissue within the same image. The conventional "hard" classification method restricts each pixel exclusively to one class and often results in crisp results. Fuzzy C-mean (FCM) classification or "soft" segmentation has been extensively applied to MR images, in which pixels are partially classified into multiple classes using varying memberships to the classes. Standard FCM, however, is sensitive to noise and cannot effectively compensate for intensity inhomogeneities. This paper presents a method to obtain accurate MR brain classification using a modified multiscale and multiblock FCM.|An automatic, multiscale and multiblock fuzzy C-means (MsbFCM) classification method with MR intensity correction is presented in this paper. We use a bilateral filter to process MR images and to build a multiscale image series by increasing the standard deviation of spatial function and by reducing the standard deviation of range function. At each scale, we separate the image into multiple blocks and for every block a multiscale fuzzy C-means classification method is applied along the scales from the coarse to fine levels in order to overcome the effect of intensity inhomogeneity. The result from a coarse scale supervises the classification in the next fine scale. The classification method is tested with noisy MR images with intensity inhomogeneity.|Our method was compared with the conventional FCM, a modified FCM (MFCM) and multiscale FCM (MsFCM) method. Validation studies were performed on synthesized images with various contrasts, on the simulated brain MR database, and on real MR images. Our MsbFCM method consistently performed better than the conventional FCM, MFCM, and MsFCM methods. The MsbFCM method achieved an overlap ratio of 91% or higher. Experimental results using real MR images demonstrate the effectiveness of the proposed method. Our MsbFCM classification method is accurate and robust for various MR images.|As our classification method did not assume a Gaussian distribution of tissue intensity, it could be used on other image data for tissue classification and quantification. The automatic classification method can provide a useful quantification tool in neuroimaging and other applications.
%U http://www.ncbi.nlm.nih.gov/pubmed/21815363
%+ Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia 30329, USA.
%G eng