Yanjun Fu - Academia.edu (original) (raw)

Papers by Yanjun Fu

Research paper thumbnail of Magnetic resonance imaging detects early changes in microvascular permeability in xenograft tumors after treatment with the matrix metalloprotease inhibitor Prinomastat

Technology in cancer research & treatment, 2004

Macromolecular contrast medium-enhanced magnetic resonance imaging was applied to monitor the eff... more Macromolecular contrast medium-enhanced magnetic resonance imaging was applied to monitor the effect of matrix metalloprotease (MMP) inhibition on microvascular characteristics of human breast cancers implanted in athymic rats. Twice-daily intraperitoneal administration of Prinomastat over 1.5 days induced significant declines in MRI-assayed microvascular permeabilities (p<0.05); but this leak suppression effect had extinguished by the 10(th) day of MMP treatment using the same dose and time schedule. Results demonstrate that Prinomastat produces a rapid but transient decrease in tumor vascular permeability. Contrast-enhanced MRI using macromolecular contrast medium may prove useful as a biomarker for the dynamic MMP biological effect in cancers.

Research paper thumbnail of In vivo comparison of tantalum, tungsten, and bismuth enteric contrast agents to complement intravenous iodine for double-contrast dual-energy CT of the bowel

Contrast media & molecular imaging, Jan 18, 2016

To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall fro... more To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall from intraluminal contrast, we scanned 16 rabbits on a clinical DECT scanner: n = 3 using only iodinated intravenous contrast, and n = 13 double-contrast enhanced scans using iodinated intravenous contrast and experimental enteric non-iodinated contrast agents in the bowel lumen (five bismuth, four tungsten, and four tantalum based). Representative image pairs from conventional CT images and DECT iodine density maps of small bowel (116 pairs from 232 images) were viewed by four abdominal imaging attending radiologists to independently score each comparison pair on a visual analog scale (-100 to +100%) for (1) preference in small bowel wall visualization and (2) preference in completeness of intraluminal enteric contrast subtraction. Median small bowel wall visualization was scored 39 and 42 percentage points (95% CI 30-44% and 36-45%, both p < 0.001) higher for double-contrast DECT than ...

Research paper thumbnail of Risk of contrast-induced nephropathy for patients receiving intravenous vs. intra-arterial iodixanol administration

Abdominal Radiology, 2015

To compare the incidence of contrast-induced nephropathy (CIN) for intravenous vs. intra-arterial... more To compare the incidence of contrast-induced nephropathy (CIN) for intravenous vs. intra-arterial administration of iodixanol, compared to non-administration. We retrospectively identified 650 patients who had intravenous iodixanol-enhanced CT, 695 with intra-arterial iodixanol cardiac catheterization, 651 with unenhanced CT, and those who also had baseline and follow-up serum creatinine within 5 days of the exam. From the medical records, we recorded the gender, age, baseline and follow-up serum creatinine/eGFR; underlying renal injury risk factors; indication for imaging; contrast material administration volume, concentration, and route of administration; and use of pre-imaging prophylactic measures for CIN. Univariate and multivariate models were used to determine predictors of CIN. Baseline eGFR was lower for patients undergoing unenhanced CT than intravenous or intra-arterial patients (68 vs. 74.6 and 72.2, respectively, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) and not different between intravenous and intra-arterial patients (p = 0.735). Simple logistic regression did not show a difference in the rate of CIN in patients who received intravenous vs. intra-arterial iodixanol (28 of 650, 4%, vs. 28 of 695, 4%, respectively, p = 0.798), nor a higher rate of CIN than seen with unenhanced CT (45 of 651, 7%, p = 0.99 and p = 0.98 by one-sided t test). Multivariate regression modeling showed that only elevated baseline creatinine or decreased eGFR and low hematocrit/hemoglobin were associated with CIN incidence (odds ratio 1.28 and 2.5; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.023 and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.006, respectively). Elevation in serum creatinine due to intravenous and intra-arterial iodixanol administration is infrequent and is not more common than after unenhanced CT scans.

Research paper thumbnail of Long term MR signal characteristics of Ferucarbotran-labeled mesenchymal stem cells: Discrimination of intra-and extracellular iron oxides before and after cell lysis

Promising applications of stem cell based therapy include the replacement of defective tissue in ... more Promising applications of stem cell based therapy include the replacement of defective tissue in patients with diseases such as diabetes or Parkinson's (1). To evaluate the success of engraftment, it is important to generate information on the viability of the injected cells. Labeling cells for MR imaging with iron oxides provides a means of sensitive cell tracking combined with high anatomical resolution in vivo (2). Since intracellular iron oxides may be metabolized or released, the potential signal changes over time needs to be studied. Therefore, the long term signal effects of viable and dead Ferucarbotran-labeled human mesenchymal stem cells (hMSC) at 1.5T and 3T were investigated.

Research paper thumbnail of Dynamische MRT als prädiktiver Biomarker für das Tumorwachstum unter angiogenesehemmender Therapie

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2008

Research paper thumbnail of MR Imaging of Antigen-induced Arthritis: A Comparison between Ultrasmall Superparamagnetic Iron Oxides (USPIO) and Standard Gd-DTPA

PURPOSE To proof the ability of the ultrasmall superparamagnetic iron oxide (USPIO) SHU555C to de... more PURPOSE To proof the ability of the ultrasmall superparamagnetic iron oxide (USPIO) SHU555C to detect and characterize antigen-induced arthritis with magnetic resonance (MR) imaging and to compare its imaging characteristics with Gd-DTPA. METHOD AND MATERIALS An immune mediated arthritis was induced in the right knee of 12 Sprague Dawley rats. As a control, saline was injected into the left knee. Both knees were evaluated with MR imaging at 2T before and at various time points after intravenous injection of 200 micromol Fe/kg SHU555C (n=6) or 200 micromol Gd/kg Gd-DTPA (n=6), using T1-weighted gradient-echo (GE), T2-weighted spin-echo (SE) and T2*-weighted GE sequences. Signal-to-noise ratios (SNR) and relative enhancement (Delta SI%) of both knees were determined. Data were tested for significant differences between the two agents and between the arthritic and normal knees using a mixed effect model. Joint specimens were processed for histopathologic correlation. RESULTS USPIO and ...

Research paper thumbnail of Detection and Characterization of Antigen-induced Arthritis Using USPIO-enhanced Magnetic Resonance Imaging

PURPOSE To detect and characterize inflammatory processes in an established animal model with ant... more PURPOSE To detect and characterize inflammatory processes in an established animal model with antigen-induced arthritis using high resolution MR imaging enhanced with two different USPIO contrast agents. METHOD AND MATERIALS Mono-arthritis was induced in the right knee of 10 Sprague Dawley rats by sensitizing subcutaneous injections of complete Freund's adjuvant and intraarticular injections of methylated bovine serum albumin. As an internal control, sterile saline was injected into the left knee. Both knees were evaluated with high resolution MR imaging at 2 T before and at 30 min and 24 h after intravenous injection of 40 micromol/kg SHU 555C (n=5 rats: Resovist S) or Ferumoxtran (n=5 rats; Combidex, Sinerem). Pulse sequences comprised T2-TSE 90/100/20,40,60,80 (flip angle/TR/TE) and T2*-GE 30/100/15 sequences. Signal-to-noise ratios (SNR) of the inflamed knees, the contralateral normal knees and paraarticular muscle were determined. Statistical analyses were performed with an...

Research paper thumbnail of Dynamische MRT zur Überwachung der Wirkung von Thalidomid auf ein experimentelles humanes Mamma-Karzinom

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2008

Research paper thumbnail of Hepatic and Bile Duct Motion Artifact at CT Cholangiography

PURPOSE To investigate the frequency, severity, location, and causes of hepatobiliary motion arti... more PURPOSE To investigate the frequency, severity, location, and causes of hepatobiliary motion artifact at CT cholangiography and liver excursion at cardiac cine MR. METHOD AND MATERIALS In this institutional review board approved, HIPPA compliant retrospective study, 143 living potential liver donors underwent contrast-enhanced CT cholangiography. Two readers by consensus rated artifact severity at the left and right intrahepatic ducts, infracardiac and perigastric liver parenchyma, and whole liver, and measured infracardiac and perigastric liver parenchymal artifact depth and liver extension into the left abdomen. The difference between left and right artifact severity ratings and association of artifact severity rating with the measurements were analyzed using generalized estimation equations. In a second set of 24 cardiac cine MR scans, two readers by consensus measured the maximum excursion of the superior liver edge on the right and left side of the abdomen. RESULTS Artifact sev...

Research paper thumbnail of Trauma Imaging with Color Contrast for Color CT: In Vivo Use of Complementary Contrast Materials at Dual-energy Computed Tomography

PURPOSE We evaluate the ability of a clinical dual-energy computed tomography (DECT) scanner to v... more PURPOSE We evaluate the ability of a clinical dual-energy computed tomography (DECT) scanner to visually separate pairs of contrast materials selected for maximal differentiability in phantoms and in vivo in a rat cardiac and rabbit abdominal trauma model. We compare accuracy, confidence and speed of diagnosis between conventional CT and dual contrast DECT abdominal trauma imaging. METHOD AND MATERIALS Phantoms with varying concentrations of iodine/tungsten and iodine/bismuth were scanned on a rapid kVp switching DECT scanner. In vivo DECT scans were performed on a rat enhanced with iodinated and tungsten-cluster intravenous contrast agents delivered 15 seconds apart. Five rabbits with bowel and/or vascular penetrating trauma were imaged with simultaneous iodinated intravenous and bismuth subsalicylate enteric contrast at DECT. 10 radiologists without prior DECT experience each evaluated 10 extralumenal collections to record vascular and/or enteric origin of extravasation and their ...

Research paper thumbnail of Discontinuation of Positive Oral Contrast for Routine CT Scans Does Not Result in Substantial Repeat Scans

PURPOSE To evaluate the rate of repeat scans after an institution-wide policy to discontinue the ... more PURPOSE To evaluate the rate of repeat scans after an institution-wide policy to discontinue the routine administration of positive oral contrast in favor of oral tap water for routine abdominal CT examinations. METHOD AND MATERIALS From a total of 12,370 abdominal CT scans performed at our institution from March 9, 2009 to June 26, 2012, we identified all repeat abdominal CT scans occurring between 2 hours and 14 days after an initial abdominal CT scan. On March 9, 2009 our department discontinued the routine administration of positive oral (iodinated) contrast in favor of oral tap water for such scans. Readers recorded the presence of oral and IV contrast in both initial and repeat abdominal CT scans images. For scans in which positive oral contrast was given, the reason for administering oral contrast was given.. RESULTS From a total of 12,370 abdominal CT examinations, 439 (3.5%) were repeat scans, and of these, 47 scans (10.7%) used oral contrast on the repeat CT scan but not t...

Research paper thumbnail of Contrast-enhanced CT Quantification of Hepatic Fibrosis

PURPOSE To evaluate the possibility of using contrast-enhanced CT measurements of the fractional ... more PURPOSE To evaluate the possibility of using contrast-enhanced CT measurements of the fractional extracellular space (fECS) and macromolecular contrast material (MMCM) retention in the liver to quantify the severity of hepatic fibrosis. METHOD AND MATERIALS Twenty-one rats were treated with intragastric CCl4 for 2 to 12 weeks in order to induce a wide range of hepatic fibrosis. Three rats were imaged every two weeks by respiratory-gated micro-CT using both a conventional contrast material and a novel polyethylene glycol-derived polylysine dendrimer as an iodinated macromolecular contrast material (MMCM). Immediately after scanning, the livers were removed, fixed in formalin, and stained with Picrosirius Red. Hepatic fibrosis was graded qualitatively using the Ishak fibrosis score (0-6) and quantitatively by morphometry. All measurements of liver fibrosis were made in a blinded fashion. The hepatic fECS and MMCM retention were calculated for each animal scan and correlated with the h...

Research paper thumbnail of A Multi-Level Scene Matching Algorithm Based on Adaptive Polar Transform

2010 International Conference on Computational Intelligence and Software Engineering, 2010

In the scene matching aided-navigation system, there often exists rotation, scale difference and ... more In the scene matching aided-navigation system, there often exists rotation, scale difference and occlusion between actual image and reference image. According to the navigation system demands of robustness, instantaneity and precision, a multi-level algorithm based on adaptive polar transform is proposed for its robustness to rotation, scale difference and occlusion. In the matching process, the rectangle window is replaced by

Research paper thumbnail of <title>A measuring technology for fiber connector end surface</title>

Advanced Materials and Devices for Sensing and Imaging II, 2005

A non-contact optical microscopy system is described. It adopts basic Michelson structure to meas... more A non-contact optical microscopy system is described. It adopts basic Michelson structure to measure the characteristic of end surface of the fiber connector. We take use of the Fourier transform to process interference pattern. Getting the high information of two-dimension section picture. We take use of the First Derivative is extremum and Second Derivative is zero to detect the edge jump points. And we take use of Least Square Method etc. curve fitting method to describe the two-dimension section picture. We analyze the method to measure geometrical parameters of end surface. Then we can measure the characteristic of end surface. For example: the geometric parameters and roughness.

Research paper thumbnail of On-line learning skin model based on similarity between neighboring pixels

2010 IEEE 2nd Symposium on Web Society, 2010

As we know, many natural objects have similar color as human skin, e.g., sand, desert etc. The ob... more As we know, many natural objects have similar color as human skin, e.g., sand, desert etc. The objects with skin-like color in images make the skin detection in images become challenging. In this paper, we present an approach to on-line learning skin model based on similarity between neighboring pixels, and combine it with region-growth technique to segment skin regions. Our skin model assumes the colors of neighboring skin pixels in YCbCr color space satisfies conditional Gaussian distribution, and estimate the parameters of the Gaussian distributions in an on-line way. In detection, our algorithm first evaluates the color distance map in RGB space to reliably identify some skin and non-skin regions. Then the skin regions can be further segmented out based on our skin models. The experimental results show our approach has a very high accuracy.

Research paper thumbnail of MR-Bildgebung der Antigen-induzierten Arthritis mit dem neuen Folat-Rezeptor-spezifischen MR-Kontrastmittel P866

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2006

Research paper thumbnail of Fringe projection profilometry based on a novel phase shift method

Optics express, Jan 24, 2011

Fringe projection profilometry is generally used to measure the 3D shape of an object. In oblique... more Fringe projection profilometry is generally used to measure the 3D shape of an object. In oblique-angle projection, the grating fringe cycle is broadened on the reference surface. A well-fitted, convenient, and quick cycle correction method is proposed in this study. Based on the proposed method, an accurate four-step phase shift method is developed. Comparative experiments show that the fringe projection profilometry based on the novel phase shift method can eliminate cycle error and significantly improve measurement accuracy. The relative error of the measurement is less than 1.5%. This method can be widely employed for measuring large objects.

Research paper thumbnail of The modeling research of blade based on UG

2010 International Conference on Mechanic Automation and Control Engineering, 2010

Blade is one of the most important work pieces in Aero-engine. Owing to its structural complexity... more Blade is one of the most important work pieces in Aero-engine. Owing to its structural complexity and irregularity, the three-dimensional digital point cloud of blade is obtained by projecting grating method, and UG software is used to carry on impeller and blade of solid modeling via data processing and 3D model of improvement. The design accuracy and efficiency of blade

Research paper thumbnail of 3D shape measurement of larger complex objects based on fringe cycle correction

Chinese Optics Letters, 2014

Research paper thumbnail of A Fast Scene Matching Algorithm Based on Pixel-Jump Method

2009 International Symposium on Computer Network and Multimedia Technology, 2009

According to the image matching demands of both the precision and instantaneity, a real-time two-... more According to the image matching demands of both the precision and instantaneity, a real-time two-level scene matching algorithm is proposed based on the least trimmed square Hausdorff distance (LTS-HD). In the first level, a coarse match point is obtained using pixel-jump searching through the reference image. In the second level, a point-by-point local searching is performed to get the accurate match point within the ¿ -neighborhood around the coarse point. Simulation results show that the proposed image matching algorithm takes little time and the point is correct.

Research paper thumbnail of Magnetic resonance imaging detects early changes in microvascular permeability in xenograft tumors after treatment with the matrix metalloprotease inhibitor Prinomastat

Technology in cancer research & treatment, 2004

Macromolecular contrast medium-enhanced magnetic resonance imaging was applied to monitor the eff... more Macromolecular contrast medium-enhanced magnetic resonance imaging was applied to monitor the effect of matrix metalloprotease (MMP) inhibition on microvascular characteristics of human breast cancers implanted in athymic rats. Twice-daily intraperitoneal administration of Prinomastat over 1.5 days induced significant declines in MRI-assayed microvascular permeabilities (p<0.05); but this leak suppression effect had extinguished by the 10(th) day of MMP treatment using the same dose and time schedule. Results demonstrate that Prinomastat produces a rapid but transient decrease in tumor vascular permeability. Contrast-enhanced MRI using macromolecular contrast medium may prove useful as a biomarker for the dynamic MMP biological effect in cancers.

Research paper thumbnail of In vivo comparison of tantalum, tungsten, and bismuth enteric contrast agents to complement intravenous iodine for double-contrast dual-energy CT of the bowel

Contrast media & molecular imaging, Jan 18, 2016

To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall fro... more To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall from intraluminal contrast, we scanned 16 rabbits on a clinical DECT scanner: n = 3 using only iodinated intravenous contrast, and n = 13 double-contrast enhanced scans using iodinated intravenous contrast and experimental enteric non-iodinated contrast agents in the bowel lumen (five bismuth, four tungsten, and four tantalum based). Representative image pairs from conventional CT images and DECT iodine density maps of small bowel (116 pairs from 232 images) were viewed by four abdominal imaging attending radiologists to independently score each comparison pair on a visual analog scale (-100 to +100%) for (1) preference in small bowel wall visualization and (2) preference in completeness of intraluminal enteric contrast subtraction. Median small bowel wall visualization was scored 39 and 42 percentage points (95% CI 30-44% and 36-45%, both p < 0.001) higher for double-contrast DECT than ...

Research paper thumbnail of Risk of contrast-induced nephropathy for patients receiving intravenous vs. intra-arterial iodixanol administration

Abdominal Radiology, 2015

To compare the incidence of contrast-induced nephropathy (CIN) for intravenous vs. intra-arterial... more To compare the incidence of contrast-induced nephropathy (CIN) for intravenous vs. intra-arterial administration of iodixanol, compared to non-administration. We retrospectively identified 650 patients who had intravenous iodixanol-enhanced CT, 695 with intra-arterial iodixanol cardiac catheterization, 651 with unenhanced CT, and those who also had baseline and follow-up serum creatinine within 5 days of the exam. From the medical records, we recorded the gender, age, baseline and follow-up serum creatinine/eGFR; underlying renal injury risk factors; indication for imaging; contrast material administration volume, concentration, and route of administration; and use of pre-imaging prophylactic measures for CIN. Univariate and multivariate models were used to determine predictors of CIN. Baseline eGFR was lower for patients undergoing unenhanced CT than intravenous or intra-arterial patients (68 vs. 74.6 and 72.2, respectively, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) and not different between intravenous and intra-arterial patients (p = 0.735). Simple logistic regression did not show a difference in the rate of CIN in patients who received intravenous vs. intra-arterial iodixanol (28 of 650, 4%, vs. 28 of 695, 4%, respectively, p = 0.798), nor a higher rate of CIN than seen with unenhanced CT (45 of 651, 7%, p = 0.99 and p = 0.98 by one-sided t test). Multivariate regression modeling showed that only elevated baseline creatinine or decreased eGFR and low hematocrit/hemoglobin were associated with CIN incidence (odds ratio 1.28 and 2.5; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.023 and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.006, respectively). Elevation in serum creatinine due to intravenous and intra-arterial iodixanol administration is infrequent and is not more common than after unenhanced CT scans.

Research paper thumbnail of Long term MR signal characteristics of Ferucarbotran-labeled mesenchymal stem cells: Discrimination of intra-and extracellular iron oxides before and after cell lysis

Promising applications of stem cell based therapy include the replacement of defective tissue in ... more Promising applications of stem cell based therapy include the replacement of defective tissue in patients with diseases such as diabetes or Parkinson's (1). To evaluate the success of engraftment, it is important to generate information on the viability of the injected cells. Labeling cells for MR imaging with iron oxides provides a means of sensitive cell tracking combined with high anatomical resolution in vivo (2). Since intracellular iron oxides may be metabolized or released, the potential signal changes over time needs to be studied. Therefore, the long term signal effects of viable and dead Ferucarbotran-labeled human mesenchymal stem cells (hMSC) at 1.5T and 3T were investigated.

Research paper thumbnail of Dynamische MRT als prädiktiver Biomarker für das Tumorwachstum unter angiogenesehemmender Therapie

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2008

Research paper thumbnail of MR Imaging of Antigen-induced Arthritis: A Comparison between Ultrasmall Superparamagnetic Iron Oxides (USPIO) and Standard Gd-DTPA

PURPOSE To proof the ability of the ultrasmall superparamagnetic iron oxide (USPIO) SHU555C to de... more PURPOSE To proof the ability of the ultrasmall superparamagnetic iron oxide (USPIO) SHU555C to detect and characterize antigen-induced arthritis with magnetic resonance (MR) imaging and to compare its imaging characteristics with Gd-DTPA. METHOD AND MATERIALS An immune mediated arthritis was induced in the right knee of 12 Sprague Dawley rats. As a control, saline was injected into the left knee. Both knees were evaluated with MR imaging at 2T before and at various time points after intravenous injection of 200 micromol Fe/kg SHU555C (n=6) or 200 micromol Gd/kg Gd-DTPA (n=6), using T1-weighted gradient-echo (GE), T2-weighted spin-echo (SE) and T2*-weighted GE sequences. Signal-to-noise ratios (SNR) and relative enhancement (Delta SI%) of both knees were determined. Data were tested for significant differences between the two agents and between the arthritic and normal knees using a mixed effect model. Joint specimens were processed for histopathologic correlation. RESULTS USPIO and ...

Research paper thumbnail of Detection and Characterization of Antigen-induced Arthritis Using USPIO-enhanced Magnetic Resonance Imaging

PURPOSE To detect and characterize inflammatory processes in an established animal model with ant... more PURPOSE To detect and characterize inflammatory processes in an established animal model with antigen-induced arthritis using high resolution MR imaging enhanced with two different USPIO contrast agents. METHOD AND MATERIALS Mono-arthritis was induced in the right knee of 10 Sprague Dawley rats by sensitizing subcutaneous injections of complete Freund's adjuvant and intraarticular injections of methylated bovine serum albumin. As an internal control, sterile saline was injected into the left knee. Both knees were evaluated with high resolution MR imaging at 2 T before and at 30 min and 24 h after intravenous injection of 40 micromol/kg SHU 555C (n=5 rats: Resovist S) or Ferumoxtran (n=5 rats; Combidex, Sinerem). Pulse sequences comprised T2-TSE 90/100/20,40,60,80 (flip angle/TR/TE) and T2*-GE 30/100/15 sequences. Signal-to-noise ratios (SNR) of the inflamed knees, the contralateral normal knees and paraarticular muscle were determined. Statistical analyses were performed with an...

Research paper thumbnail of Dynamische MRT zur Überwachung der Wirkung von Thalidomid auf ein experimentelles humanes Mamma-Karzinom

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2008

Research paper thumbnail of Hepatic and Bile Duct Motion Artifact at CT Cholangiography

PURPOSE To investigate the frequency, severity, location, and causes of hepatobiliary motion arti... more PURPOSE To investigate the frequency, severity, location, and causes of hepatobiliary motion artifact at CT cholangiography and liver excursion at cardiac cine MR. METHOD AND MATERIALS In this institutional review board approved, HIPPA compliant retrospective study, 143 living potential liver donors underwent contrast-enhanced CT cholangiography. Two readers by consensus rated artifact severity at the left and right intrahepatic ducts, infracardiac and perigastric liver parenchyma, and whole liver, and measured infracardiac and perigastric liver parenchymal artifact depth and liver extension into the left abdomen. The difference between left and right artifact severity ratings and association of artifact severity rating with the measurements were analyzed using generalized estimation equations. In a second set of 24 cardiac cine MR scans, two readers by consensus measured the maximum excursion of the superior liver edge on the right and left side of the abdomen. RESULTS Artifact sev...

Research paper thumbnail of Trauma Imaging with Color Contrast for Color CT: In Vivo Use of Complementary Contrast Materials at Dual-energy Computed Tomography

PURPOSE We evaluate the ability of a clinical dual-energy computed tomography (DECT) scanner to v... more PURPOSE We evaluate the ability of a clinical dual-energy computed tomography (DECT) scanner to visually separate pairs of contrast materials selected for maximal differentiability in phantoms and in vivo in a rat cardiac and rabbit abdominal trauma model. We compare accuracy, confidence and speed of diagnosis between conventional CT and dual contrast DECT abdominal trauma imaging. METHOD AND MATERIALS Phantoms with varying concentrations of iodine/tungsten and iodine/bismuth were scanned on a rapid kVp switching DECT scanner. In vivo DECT scans were performed on a rat enhanced with iodinated and tungsten-cluster intravenous contrast agents delivered 15 seconds apart. Five rabbits with bowel and/or vascular penetrating trauma were imaged with simultaneous iodinated intravenous and bismuth subsalicylate enteric contrast at DECT. 10 radiologists without prior DECT experience each evaluated 10 extralumenal collections to record vascular and/or enteric origin of extravasation and their ...

Research paper thumbnail of Discontinuation of Positive Oral Contrast for Routine CT Scans Does Not Result in Substantial Repeat Scans

PURPOSE To evaluate the rate of repeat scans after an institution-wide policy to discontinue the ... more PURPOSE To evaluate the rate of repeat scans after an institution-wide policy to discontinue the routine administration of positive oral contrast in favor of oral tap water for routine abdominal CT examinations. METHOD AND MATERIALS From a total of 12,370 abdominal CT scans performed at our institution from March 9, 2009 to June 26, 2012, we identified all repeat abdominal CT scans occurring between 2 hours and 14 days after an initial abdominal CT scan. On March 9, 2009 our department discontinued the routine administration of positive oral (iodinated) contrast in favor of oral tap water for such scans. Readers recorded the presence of oral and IV contrast in both initial and repeat abdominal CT scans images. For scans in which positive oral contrast was given, the reason for administering oral contrast was given.. RESULTS From a total of 12,370 abdominal CT examinations, 439 (3.5%) were repeat scans, and of these, 47 scans (10.7%) used oral contrast on the repeat CT scan but not t...

Research paper thumbnail of Contrast-enhanced CT Quantification of Hepatic Fibrosis

PURPOSE To evaluate the possibility of using contrast-enhanced CT measurements of the fractional ... more PURPOSE To evaluate the possibility of using contrast-enhanced CT measurements of the fractional extracellular space (fECS) and macromolecular contrast material (MMCM) retention in the liver to quantify the severity of hepatic fibrosis. METHOD AND MATERIALS Twenty-one rats were treated with intragastric CCl4 for 2 to 12 weeks in order to induce a wide range of hepatic fibrosis. Three rats were imaged every two weeks by respiratory-gated micro-CT using both a conventional contrast material and a novel polyethylene glycol-derived polylysine dendrimer as an iodinated macromolecular contrast material (MMCM). Immediately after scanning, the livers were removed, fixed in formalin, and stained with Picrosirius Red. Hepatic fibrosis was graded qualitatively using the Ishak fibrosis score (0-6) and quantitatively by morphometry. All measurements of liver fibrosis were made in a blinded fashion. The hepatic fECS and MMCM retention were calculated for each animal scan and correlated with the h...

Research paper thumbnail of A Multi-Level Scene Matching Algorithm Based on Adaptive Polar Transform

2010 International Conference on Computational Intelligence and Software Engineering, 2010

In the scene matching aided-navigation system, there often exists rotation, scale difference and ... more In the scene matching aided-navigation system, there often exists rotation, scale difference and occlusion between actual image and reference image. According to the navigation system demands of robustness, instantaneity and precision, a multi-level algorithm based on adaptive polar transform is proposed for its robustness to rotation, scale difference and occlusion. In the matching process, the rectangle window is replaced by

Research paper thumbnail of <title>A measuring technology for fiber connector end surface</title>

Advanced Materials and Devices for Sensing and Imaging II, 2005

A non-contact optical microscopy system is described. It adopts basic Michelson structure to meas... more A non-contact optical microscopy system is described. It adopts basic Michelson structure to measure the characteristic of end surface of the fiber connector. We take use of the Fourier transform to process interference pattern. Getting the high information of two-dimension section picture. We take use of the First Derivative is extremum and Second Derivative is zero to detect the edge jump points. And we take use of Least Square Method etc. curve fitting method to describe the two-dimension section picture. We analyze the method to measure geometrical parameters of end surface. Then we can measure the characteristic of end surface. For example: the geometric parameters and roughness.

Research paper thumbnail of On-line learning skin model based on similarity between neighboring pixels

2010 IEEE 2nd Symposium on Web Society, 2010

As we know, many natural objects have similar color as human skin, e.g., sand, desert etc. The ob... more As we know, many natural objects have similar color as human skin, e.g., sand, desert etc. The objects with skin-like color in images make the skin detection in images become challenging. In this paper, we present an approach to on-line learning skin model based on similarity between neighboring pixels, and combine it with region-growth technique to segment skin regions. Our skin model assumes the colors of neighboring skin pixels in YCbCr color space satisfies conditional Gaussian distribution, and estimate the parameters of the Gaussian distributions in an on-line way. In detection, our algorithm first evaluates the color distance map in RGB space to reliably identify some skin and non-skin regions. Then the skin regions can be further segmented out based on our skin models. The experimental results show our approach has a very high accuracy.

Research paper thumbnail of MR-Bildgebung der Antigen-induzierten Arthritis mit dem neuen Folat-Rezeptor-spezifischen MR-Kontrastmittel P866

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2006

Research paper thumbnail of Fringe projection profilometry based on a novel phase shift method

Optics express, Jan 24, 2011

Fringe projection profilometry is generally used to measure the 3D shape of an object. In oblique... more Fringe projection profilometry is generally used to measure the 3D shape of an object. In oblique-angle projection, the grating fringe cycle is broadened on the reference surface. A well-fitted, convenient, and quick cycle correction method is proposed in this study. Based on the proposed method, an accurate four-step phase shift method is developed. Comparative experiments show that the fringe projection profilometry based on the novel phase shift method can eliminate cycle error and significantly improve measurement accuracy. The relative error of the measurement is less than 1.5%. This method can be widely employed for measuring large objects.

Research paper thumbnail of The modeling research of blade based on UG

2010 International Conference on Mechanic Automation and Control Engineering, 2010

Blade is one of the most important work pieces in Aero-engine. Owing to its structural complexity... more Blade is one of the most important work pieces in Aero-engine. Owing to its structural complexity and irregularity, the three-dimensional digital point cloud of blade is obtained by projecting grating method, and UG software is used to carry on impeller and blade of solid modeling via data processing and 3D model of improvement. The design accuracy and efficiency of blade

Research paper thumbnail of 3D shape measurement of larger complex objects based on fringe cycle correction

Chinese Optics Letters, 2014

Research paper thumbnail of A Fast Scene Matching Algorithm Based on Pixel-Jump Method

2009 International Symposium on Computer Network and Multimedia Technology, 2009

According to the image matching demands of both the precision and instantaneity, a real-time two-... more According to the image matching demands of both the precision and instantaneity, a real-time two-level scene matching algorithm is proposed based on the least trimmed square Hausdorff distance (LTS-HD). In the first level, a coarse match point is obtained using pixel-jump searching through the reference image. In the second level, a point-by-point local searching is performed to get the accurate match point within the ¿ -neighborhood around the coarse point. Simulation results show that the proposed image matching algorithm takes little time and the point is correct.