Dynamic Imaging System Research Articles

Postural Function of the Diaphragm in Persons With and Without Chronic Low Back Pain

A case-control study. To examine the function of the diaphragm during postural limb activities in patients with chronic low back pain and healthy controls. Abnormal stabilizing function of the diaphragm may be an etiological factor in spinal disorders. However, a study designed specifically to test the dynamics of the diaphragm in chronic spinal disorders is lacking. Eighteen patients with chronic low back pain due to chronic overloading, as ascertained via clinical assessment and magnetic resonance imaging, and 29 healthy subjects were examined. Both groups presented with normal pulmonary function test results. A dynamic magnetic resonance imaging system and specialized spirometric readings were used with subjects in the supine position. Measurements during tidal breathing (TB) and isometric flexion of the upper and lower extremities against external resistance with TB were performed. Standard pulmonary function tests, including respiratory muscle drive (PI(max) and PE(max)), were also assessed. Using multivariate analysis of covariance, smaller diaphragm excursions and higher diaphragm position were found in the patient group (P<.05) during the upper extremity TB and lower extremity TB conditions. Maximum changes were found in costal and middle points of the diaphragm. A 1-way analysis of covariance showed a steeper slope in the middle-posterior diaphragm in the patient group both in the upper extremity TB and lower extremity TB conditions (P<.05). Patients with chronic low back pain appear to have both abnormal position and a steeper slope of the diaphragm, which may contribute to the etiology of the disorder.

Does close proximity robot motion tracking alter gait?

Dynamic fluoroscopic imaging and three-dimensional model-image registration techniques provide detailed joint kinematic measurements for motions constrained to small volumes of space. Several groups are working to mount radiographic imaging hardware onto mobile platforms to provide these same imaging capabilities for observation of unrestricted activities. These dynamic radiographic imaging systems could provide accurate skeletal kinematics during a wide range of clinically relevant, daily activities. However, the premise that people move naturally when followed by a dynamic imaging system has not been evaluated. The goal of this study was to determine if a close-up robot tracking system affects natural free-speed gait. 14 healthy adults were recruited to walk through the workspace of a dynamic radiographic imaging system. Randomized walking trials were performed with and without the dynamic imaging system tracking the motions of the subject’s left knee. With- and without-robot trials were compared using detailed temporal–spatial and frequency analysis of kinematic and kinetic parameters. On average, participants increase their stride length by 0.9 cm. There also were slight increases in unexplained variation in ankle flexion/extension and ground reaction forces compared to baseline measurements. The statistically significant differences indicate that, on average, people tried to move faster through the workspace of the dynamic radiographic imaging system while it was actively tracking their motion. These differences are small and potentially clinically irrelevant.

Value of renal parenchymal volume and thickness by non-contrast spiral CT in evaluating differential glomerular filtration rate for chronic obstructed kidneys

Objective To evaluate the value of renal parenchymal volume and thickness by non-contrast spiral CT in evaluating the differential glomerular filtration rate (GFR) for chronic obstructed kidneys, and to compare the correlations between the two morphologic indices of renal parenchyma and the GFR for chronic obstructed kidneys. Methods Seventy-one patients who had a diagnosis of unilateral chronic upper urinary tract obstruction were included in this analysis. (1) The renal parenchymal volume was mea-sured by non-contrast spiral CT. Both kidneys were scanned by non-contrast spiral CT. The renal parenchymal area of each section was marked manually. Renal parenchymal volume was calculated as the sum of renal parenchymal area multiplied by the width of each section. The volume percentage of obstructed kidney (%CTvol) was also calculated. (2) Renal parenchymal thickness was measured on the first and last non-contrast CT image levels from the anterior, posterior and lateral locations of the kidney that clearly contained the collecting system. The mean of these measurements was defined as the renal parenchymal thickness. The differential renal parenchymal thickness of the obstructed kidney (%CTt) was defined as the percentage of the obstructed renal parenchymal thickness to the total renal parenchymal thickness for both kidneys. GFR was determined with 99Tcm-DTPA dynamic imaging system by Gates method. The differential GFR for obstructed kidney (%GFR) was the GFR percentage of obstructed kidney to the total GFR for both kidneys. The Pearson relation test was carried out between the %CTvol, %CTt and the %GFR respectively. Results %CTvol and %CTt correlated well with %GFR in chronic obstructed kidneys among the 71 test group patients. Pearson correlation coefficient r was 0.80 (t=11.20, P＜0.05) and 0.66 (t=7.24, P＜0.05), respectively. The linear correlation equation respectively was %GFR=0.05+0.80×%CTvol (F=125.48, P＜0.05) and %GFR=0.12+0.66×%CTt (F=52.36, P＜0.05). Conclusions Renal parenchymal volume and thickness by non-contrast spiral CT might be used as clinical practical parameters to evaluate the differential GFR for chronic obstructed kidneys. Renal parenchymal volume is more accurate than renal parenchymal thickness. Key words: Tomography, X-ray computed; Renal parenchyma; Glomerular filtration rate; Renal dynamic imaging; Obstruction

Digital optical tomography system for dynamic breast imaging

Diffuse optical tomography has shown promising results as a tool for breast cancer screening and monitoring response to chemotherapy. Dynamic imaging of the transient response of the breast to an external stimulus, such as pressure or a respiratory maneuver, can provide additional information that can be used to detect tumors. We present a new digital continuous-wave optical tomography system designed to simultaneously image both breasts at fast frame rates and with a large number of sources and detectors. The system uses a master-slave digital signal processor-based detection architecture to achieve a dynamic range of 160 dB and a frame rate of 1.7 Hz with 32 sources, 64 detectors, and 4 wavelengths per breast. Included is a preliminary study of one healthy patient and two breast cancer patients showing the ability to identify an invasive carcinoma based on the hemodynamic response to a breath hold.

基于互信息的高动态范围成像系统成像质量分析

For optimizing design of the High Dynamic Range Imaging system and evaluating its performance perfectly,the information theory is applied to the High Dynamic Range Imaging system,the High Dynamic Range Imaging system is considered as a communication system,and the image quality of High Dynamic Range Imaging system is evaluated according to the end-to-end mutual information.Introducing the influence of LCoS as a spatial light modulator to CMOS sampling imaging model,mathematical model of the High Dynamic Range Imaging system based on mutual information is established.According to the model,the factors,such as the ratio of LCoS pixel number to CMOS pixel number,aperture ratio of LCoS and CMOS pixel,relative displacement and relative rotation angle,which affect the mutual information,and the reasons why the system image quality decline are analyzed.According to computer simulation,the relationships between the ratio of LCoS pixel number to CMOS pixel number and the mutual information,aperture ratio of LCoS and CMOS pixel and the mutual information,relative displacement and the mutual information,relative rotation angle and the mutual information are demonstrated,and the influence of these factors on the mutual information is analyzed.The simulation results show that the best matching condition between LCoS array and CMOS array is that one LCoS pixel corresponds to one CMOS pixel with smaller CMOS pixel,higher aperture of LCoS and CMOS pixel,no relative displacement and no relative rotation.

Rectal Anatomy After Rectopexy: Cinedefecography Versus MR-Defecography

Conventional defecography can reveal abnormalities in patients with evacuatory disorders. With fast dynamic MR imaging systems, MR-defecography has become possible, which does not expose patients to ionizing radiation. The purpose of this study was to assess the correlation of both methods after rectopexy. Twenty-one consecutive patients underwent abdominal sigmoidectomy and rectopexy due to evacuatory disorders. Postoperatively, all patients were investigated by cineradiographic defecography. Fourteen patients underwent MR-defecography additionally. The results were screened for anorectal angle and pelvic floor position (rest, squeezing, and evacuation). The findings were depicted in Box plot analysis and compared with the Friedman-test. Descent of pelvic organs was also assessed. In MR-defecography, anorectal angle at rest was smaller than in conventional defecography, but there was no difference during squeezing and defecation. Concerning pelvic floor position, during squeezing, MR-defecography illustrated a lower perineum and a broader range of pelvic settings, but no difference at rest and during evacuation. In four patients, MR-defecography visualized a descent of the bladder. However, in four patients with complete evacuation in cineradiography and with no clinical complaints about incomplete evacuation, MR imaging showed deficient evacuation. Overall continence of patients was significantly improved through surgery, but there was no change in sphincter pressure, radial asymmetry, or sphincter length. In general, with respect to anorectal angle and perineal motility, both methods revealed consistent results. The concomitant depiction of structures in MR-defecography is helpful in the assessment of descent of pelvic organs and permits visualization of enteroceles. However, in 30% of patients, MR-defecography wrongly showed incomplete evacuation.

Dynamic sediment profile imaging (DySPI): a new field method for the study of dynamic processes at the sediment‐water interface

Sediment transport processes at the sediment‐water interface are usually studied using flume tests. Due to technical limitations, extreme hydro‐sedimentary conditions are then rarely considered. Sediment profile imaging (SPI) is a widely used technique for mapping benthic habitat quality in soft sediments but several limitations exist that make the system ineffective for coarse or indurate sediment investigations and for transport processes studies. To address this problem, a modified system was designed to investigate these processes in situ, on a grain‐size scale, with high temporal resolution. A dynamic sediment profile imaging (DySPI) system was constructed with a new mode of penetration, an appropriate design and an imaging system based on high‐definition video recording. The supporting frame was instrumented with autonomous sensors to monitor boundary layer characteristics along with video observations. This system was deployed during spring tide on sediment characterized by a mixture of particle sizes dominated by coarse grains. Appropriate image processing allowed determination of the area of sediment entrained, movement threshold, size of moving particles, instantaneous transport rate and interface profile changes, in addition to usual SPI parameters. However, DySPI is a prototype and further development of the instrument and the image processing are possible to enlarge the scope presented in this study.

Design and Benchtop Validation of a Handheld Integrated Dynamic Breast Imaging System for Noninvasive Characterization of Suspicious Breast Lesions

We have developed a portable, handheld, integrated, dynamic breast imaging system that integrates a near infrared tissue oximeter, clinical ultrasound, and two pressure sensors for noninvasive detection of pressure-induced structural and functional dynamics of suspicious breast lesions. A series of benchtop tests were conducted to validate multiple performance characteristics of the integrated dynamic near infrared/ultrasound breast imaging system (idNIRUS), including the reconstruction of the absorptive heterogeneities and the generation of the dynamic compression stimuli. In absorptive heterogeneity testing, we reconstructed the absorption coefficients of transparent polypropylene tubing circulated with a skim milk-India ink mixture and embedded in a gel wax tissue simulating phantom. High linear correlations (R(2) greater than 0.989) were observed between the reconstructed and the measured absorption coefficients of the embedded tubing. In dynamic compression testing, five volunteer operators generated ten successive compression sessions by compressing the idNIRUS imager on a breast self examination wearable model following the computer simulated pressure profile. The manually generated pressure profiles demonstrated an accuracy of 95.7% and operator-dependent variation of less than 5%. The results of the current benchtop tests will help to optimize the most appropriate testing conditions for our future planned clinical trial.

A real-time dynamic imaging system for centrifugal microflow platforms

Based on the operational concept of quasi-static state and optoelectronic measurement technology, this research develops a real-time dynamic imaging system for centrifugal microfluidic platforms. Unlike the conventional centrifugal inspection system, which can only be used for examination of the final steady stage in microflow analysis, the developed system with a multi-speed controller and object tracking design is fabricated with low cost to recognize dynamic microflow patterns for different kinds of compact disc-type centrifugal microstructures. The characteristics of rotational control efficiency and image acquisition quality are obtained from fluidic microvalve experiments that are achieved in measuring microflow dynamic responses and in visualizing transient microflow patterns. A man–machine interface was connected with a computer to perform the control and alignment adjustments to catch exact image data for following analysis. The rotation stability of the system has been evaluated, and the rotation speed up to 4500 rpm with vertical vibration less than ±0.2 mm is achieved measured at radial distance of 5 cm. The image acquisition is transferred via USB 2.0 at a speed of up to 30 images per second to the display and memory module.

Stability research of one kind of high dynamic range imaging system

High dynamic range imaging (HDRI) has become a topic of intense research interest in many fields. One kind of HDRI system based on the spatial light modulator (SLM) has a problem with output image instability because of feedback modulation. The HDRI system is introduced, and then a feedback modulation model for the HDRI system is established to discuss the oscillation reason for the output images. The relationship between the input light intensity and the feedback progress is analyzed. A method that adjusts the modulate index of the SLM is proposed to solve the instability problem, and the stability conditions are given to obtain stable images. Lastly, experimental images prove that the feedback model is correct and the output image with high dynamic range is stable.

Missed Lumbar Disc Herniations Diagnosed With Kinetic Magnetic Resonance Imaging

A novel dynamic magnetic resonance imaging (MRI) system, kinetic MRI (kMRI), was used to study lumbar disc herniations. The objective of this study was to determine if adding flexion and extension MRI studies to the traditional neutral views would be beneficial in the diagnosis of lumbar disc herniations. Prior studies demonstrate that only 70% of patients with lumbar disc herniations based on physical examinations are confirmed by MRI studies. Recently, kMRI delivers the ability to scan patients in neutral, flexion, and extension positions, which may allow for improved diagnosis of this problem. Five hundred fifty-three patients underwent kMRI with assessment of the degree of disc bulge in neutral and flexion and extension. The images were analyzed using computer measurement technology to objectively quantify the amount of disc herniation. For patients with normal or <3 mm of disc bulge in neutral, 19.46% demonstrated an increase in herniation to >3 mm bulge in extension, and 15.29% demonstrated an increase to >3 mm bulge in flexion. For patients in the neutral view that had a baseline disc bulge of 3 to 5 mm, 13.28% had increased herniations to >5 mm in extension and 8.47% had increased herniations to >5 mm in flexion. For patients with a baseline disc bulge of 5 to 7 mm in neutral, 10.58% increased in extension and 5.78% increased in flexion. In addition, for patients with a baseline disc bulge of 7 to 9 mm in neutral, 9.09% increased in extension and 4.55% increased in flexion. A significant increase in the degree of lumbar disc herniation was found by examining flexion and extension views when compared with neutral views alone. kMRI views provide valuable added information, especially in situations where symptomatic radiculopathy is present without any abnormalities demonstrated on conventional MRI.

High Dynamic Range Imaging by Fusing Multiple Raw Images and Tone Reproduction

This paper presents an integrated color imaging system for taking images in extremely high dynamic range scenes. The system first fuses several differently exposed raw images to acquire more intensity information. The effective dynamic range of the image raw data can be extended to 256 times if five differently exposed images are fused. Then it runs edge detection iterations to extract the image details in different luminance levels. The proposed tone reproduction algorithm equalizes the histogram of the extracted fine edges which tends to assign larger dynamic range for highly populated regions. Finally, the local contrast enhancement is performed to further refine the image details. The experimental results show that the proposed high dynamic range imaging system has good performance on both tone and color reproduction.

A Microfluidic System for Dynamic Yeast Cell Imaging

The investigation of cellular processes and gene regulatory networks within living cells requires the development of improved technology for dynamic, single cell imaging. Here, we demonstrate a microfluidic system capable of mechanical trapping of yeast cells with continuous flow and flow switching capability during time-lapse high magnification fluorescence imaging. The novel functionality of the system was validated by observing the response of pheromone-induced expression of GFP in Saccharomyces cerevisiae.

Digital-signal-processor-based dynamic imaging system for optical tomography

In this article, we introduce a dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data acquisition and filtering techniques. At the core of this continuous wave instrument is a digital signal processor (DSP) that collects, collates, processes, and filters the digitized data set. The processor is also responsible for managing system timing and the imaging routines which can acquire real-time data at rates as high as 150 Hz. Many of the synchronously timed processes are controlled by a complex programmable logic device that is also used in conjunction with the DSP to orchestrate data flow. The operation of the system is implemented through a comprehensive graphical user interface designed with LABVIEW software which integrates automated calibration, data acquisition, data organization, and signal postprocessing. Performance analysis demonstrates very low system noise (approximately 1 pW rms noise equivalent power), excellent signal precision (<0.04%-0.2%) and long term system stability (<1% over 40 min). A large dynamic range (approximately 190 dB) accommodates a wide scope of measurement geometries and tissue types. First experiments on tissue phantoms show that dynamic behavior is accurately captured and spatial location can be correctly tracked using this system.

Dynamic spectral imaging with spectral zooming capability

We report a dynamic spectral imaging system with spectral band zooming and selection capability that can adapt to different application requirements and significantly reduce the size of the captured spectral image data cube. It employs a diffraction grating to disperse the spectral information of the captured image and uses a dynamic spatial filter at the Fourier plane to select the spectral channel and spectral bandwidth for each spectral image. With a limited fixed spectral channel number, it can provide both coarse and fine spectral image viewing and capture. A prototype spectral imaging system with such spectral band zooming and selection features has been constructed. Spectral zooming from 9 to 50 nm resolution has been demonstrated.

A new approach for volumetric assessment of left ventricular function with MDCT

Cardiovascular CT is considered the diagnostic standard for establishing the presence of a functional and dynamic imaging system. It is difficult, however, to estimate the ventricular motion and volumes that are processed using hundreds and thousands of CT images, in a few moments.The main concept and design of our work are two fold — the development of effective semi-automatic tools for measuring the sequential left ventricular volumes from the hundreds or thousands of cardiac trans-axial images, and providing a simple interface with an interactive diagnostic tool for the volumetry of left ventricle and valuable cardiac 4D visualisation.We converted ten and more sequential volume data sets of the heart acquired from retrospective ECG-gating helical scan into 3D images by volume rendering. These sequential 3D images could be displayed as a movie (4D cardiac image) file. Furthermore, we developed a method for semi-automatic calculation of ejection fraction (EF) and cardiac cycle (%)-volume (ml) curve for estimation of the motion and the volume of the left ventricle. This method involved the use an interactive selection tool in the region of interest (ROI). All 3D processing methods, such as, cutting objects, segmentation, and image fusion were based on mask processing data. We now describe the software developed for cardiac 4D imaging and the estimation of ventricular volume.

Overview of clinical intravenous coronary angiography both in Japan and at ESRF

The clinical program of intravenous coronary angiography (IVCAG) using synchrotron radiation is moving on at the ESRF and at the KEK. Since the X-ray optics and types of detectors are different depending on the needs of technology, the ESRF adopts dual-energy digital subtraction system and the KEK does single-energy two-dimensional dynamic imaging system. A contrast agent is injected intravenously and the image sequence is started. The former technique enhances the image contrast of the coronary arteries in spite of intravenous injection of a contrast agent; whereas, the latter technique produces excellent temporal resolution for imaging of moving objects such as the coronary arteries and the left ventricle. So, the obtained image, the radiation dose, the examination time, and other details are different between the two facilities. Both systems sufficiently visualize the right coronary artery disease, even after coronary angioplasty or coronary artery bypass grafting. Also, the two-dimensional dynamic IVCAG permits the visualization of the left coronary arteries. The coronary morphology obtained by the IVCAG, was almost completely coincident with the results of selective CAG. Accordingly, the IVCAG is clinically validated and useful for the screening and the follow-up of coronary artery disease. However, as some portions of the left circumflex coronary artery are overlapped by the left ventricle, more contrivance is required and its imaging should be improved in future.

Theory of temporal aberrations for electron optical imaging systems by direct integral method

A new approach to calculate the temporal aberration coefficients of dynamic electron optical imaging systems is put forward in this paper. A new definition o f temporal aberration is given in which a certain initial energy of electron emi ssion along the axial direction εz1(0≤εz1≤ε0max) as a cr iterion is considered. The new method for calculating the temporal aberration c oefficients of dynamic electron optical imaging systems named “direct integral method" is presented which gives new expressions of the temporary aberration coe fficients expressed in integral form. The difference between “direct integral m ethod" and “τ-variation method" is that the “τ-variation method" n eeds to solve the differential equations for the three of temporal geometrical a berration coefficients of second order, while the “direct integral method" need s only to carry out the integral calculation of them, which is more convenient a nd suitable for computation in the practical design.

Test and verification of temporal aberration theory for electron optical imaging systems by an electrostatic concentric spherical system model

On theory of temporal aberration of dynamic electron optical imaging systems, we have put forward two methods: “τ-variation method" and “direct integral method" to calculate the temporal aberration coefficients. The difference betwe en them is that the “τ-variation method"needs to solve the differential eq uations for geometrical temporal aberration coefficients of second order, while the “direct integral method" needs only to carry out the integral calculations. The aim of the present paper is to test and verify the correctness of the two m ethods using an electrostatic concentric spherical system model. Results show th at these two methods can obtain identical solutions and the solutions of tempora l aberration coefficients of dynamic electron optical imaging systems are the sa me with the analytical solutions. Thus it can be concluded that these two method s are equivalent and correct, but the “direct integral method" is more convenie nt for computation and it could be suggested to use in the practical design.

In vivo biofluid dynamic imaging in the developing zebrafish

Flow-structure interactions are ubiquitous in nature, and are important factors in the proper development of form and function in living organisms. In order to uncover the mechanisms by which flow-structure interactions affect vertebrate development, we first need to establish the techniques necessary to quantitatively describe the fluid flow environment within the embryo. To do this, we must bring dynamic, in vivo imaging methods to bear on living systems. Traditional avian and mammalian model systems can be problematic in this regard. The zebrafish (Danio rerio) is widely accepted as an excellent model organism for the study of vertebrate biology, as it shows substantial anatomical and genetic conservation with higher vertebrates, including humans. Their small size, optical transparency, and external development make zebrafish the ideal model system for dynamic imaging. This article reviews the current state of research in imaging biofluid flow within and around developing zebrafish embryos, with an emphasis on dynamic imaging modalities.