Computer-based Imaging System Research Articles

An Endoscopic Transcanal Transpromontorial Approach for Vestibular Schwannomas using a Computer-Based Three-Dimensional Imaging System.

A 2D monocular endoscope has been used in transcanal transpromontory vestibular schwannoma surgery instead of craniotomy. However, the absence of depth perception is the limitation of this approach. With the loss of depth perception, the surgeon will be not able to perform delicate and particularly complicated surgery. A binocular endoscope has been developed to provide stereoscopic vision with better depth perception for complicated anatomic structures and has been applied in some endoscopic surgeries. However, the diameter of the endoscope is a limitation in the performance of transcanal otologic surgeries. A small diameter endoscope facilitates easier surgery in a restricted space. A computer-based 3D imaging system can obtain 3D images in real-time using a small monocular endoscope. In this study, to evaluate the feasibility of a computer-based 3D imaging system for endoscopic lateral skull base surgery, we applied this 3D imaging system in a transcanal transpromontorial approach in two patients with vestibular schwannomas. The surgical procedure was completed without complication in these two cases. There was no mortality, perioperative complications, nor notable postoperative complications. Using this computer-based 3D imaging system, a better depth perception and stereoscopic vision was observed compared to a conventional 2D endoscope. The improvement in depth perception offers superior management of the complicated surgical anatomy.

Investigation of the Effect of Different Immersion Times of Anchovy Fillets in Liquid Smoke Flavoring on Color by Image Analysis

ABSTRACT This study aimed to monitor the color changes of anchovy during the hot smoking process. For hot smoking, liquid smoke flavoring (LS) was used as an alternative to traditional smoking. The change in color was determined using the computer-based imaging system (CBI). L*, a*, and b* values were measured when anchovy samples were raw, after brining, after LS immersion, and after cooking. Various immersion times of 1, 2, and 3 minutes were tested, and resulting groups were coded as 1LS, 2LS, and 3LS, respectively. It was concluded that L*, a*, and b* values of the smoked groups did not exhibit any statistically significant difference after immersion (p > .05). Interestingly, the changes in color parameters after cooking were found to be statistically significant (p < .05). Group 1LS had a lighter color than the other LS groups upon cooking. The Delta E value of the samples also increased during the process. During the smoking process of anchovies, no color changes as a result of salting and dipping in liquid smoke solutions for different durations were observed until the final cooking step. The results of this study can help in improving the processing, preservation, and marketing aspects of smoked anchovy by controlling the color properties. Since anchovy is a small fish, smoking by traditional methods is quite challenging. Therefore, LS applications are economical and practical for these kinds of species. Although there have been studies related to the use of LS on anchovies, no research has monitored their color change.

A color and shape based algorithm for segmentation of white blood cells in peripheral blood and bone marrow images

Computer-based imaging systems are becoming important tools for quantitative assessment of peripheral blood and bone marrow samples to help experts diagnose blood disorders such as acute leukemia. These systems generally initiate a segmentation stage where white blood cells are separated from the background and other nonsalient objects. As the success of such imaging systems mainly depends on the accuracy of this stage, studies attach great importance for developing accurate segmentation algorithms. Although previous studies give promising results for segmentation of sparsely distributed normal white blood cells, only a few of them focus on segmenting touching and overlapping cell clusters, which is usually the case when leukemic cells are present. In this article, we present a new algorithm for segmentation of both normal and leukemic cells in peripheral blood and bone marrow images. In this algorithm, we propose to model color and shape characteristics of white blood cells by defining two transformations and introduce an efficient use of these transformations in a marker-controlled watershed algorithm. Particularly, these domain specific characteristics are used to identify markers and define the marking function of the watershed algorithm as well as to eliminate false white blood cells in a postprocessing step. Working on 650 white blood cells in peripheral blood and bone marrow images, our experiments reveal that the proposed algorithm improves the segmentation performance compared with its counterparts, leading to high accuracies for both sparsely distributed normal white blood cells and dense leukemic cell clusters.

Lon Peptidase 1 (LONP1)-dependent Breakdown of Mitochondrial 5-Aminolevulinic Acid Synthase Protein by Heme in Human Liver Cells

5-Aminolevulinic acid synthase (ALAS-1) is the first rate controlling enzyme that controls cellular heme biosynthesis. Negative feedback regulation of ALAS-1 by the end product heme is well documented and provides the foundation for heme treatment of acute porphyrias, a group of diseases caused by genetic defects in the heme biosynthesis pathway and exacerbated by controlled up-regulation of ALAS-1. Heme is known to affect ALAS-1 activity by repressing gene transcription, accelerating mRNA degradation, and impeding pre-ALAS-1 mitochondrial translocation. In the current study, we examined the effect of heme on the rate of mature ALAS-1 protein turnover in human cells and tissues and explored the mediator involved in this new regulatory mechanism. We found that heme and other metalloporphyrins such as CoPP and CrPP decreased mitochondrial ALAS-1 protein through proteolysis. This degradative effect cannot be emulated by iron or free protoporphyrin, two major chemical components of the heme ring, and is independent of oxidative stress. Down-regulating the activity of mitochondrial LONP1, an ATP-dependent protease that controls the selective turnover of mitochondrial matrix proteins, with potent inhibitors and specific siRNA diminished the negative effect of heme on mitochondrial ALAS-1. Therefore, our data support the existence of a conserved heme feedback regulatory mechanism that functions on the mature form of ALAS-1 protein through the activity of a mitochondrial proteolytic system.

Radiological anatomy of the donkey's foot: Objective characterisation of the normal and laminitic donkey foot

Anatomical change within a laminitic foot is of diagnostic and prognostic importance. A lateromedial radiograph represents the current 'gold standard' by which these changes are identified. Detection of anatomical change is dependent upon a priori knowledge of normality and subjective assessment alone may not identify modest change. Normal baseline data is, therefore, needed against which objective comparisons can be made. There is little information regarding the radiological anatomy of the donkey foot, hence an equine model has been widely adopted. However, descriptive accounts suggest fundamental anatomical differences between these 2 species. To characterise objectively the radiological anatomy of normal donkey feet and define the nature and extent of anatomical change associated with laminitis. The anatomy of the forefoot was quantified from lateromedial radiographs of 83 normal and 74 laminitic donkeys, using a computer based imaging system. Data were analysed using univariate and bivariate statistical methods. Baseline data were established that define the radiological characteristics of the anatomy of normal donkey feet. The key hoof, bone and weightbearing stance parameters of lateromedial radiographs have been evaluated. Laminitis was associated with significant rotation and distal displacement of the distal phalanx, increases in integument depth and morphometric change to the distal phalanx (P<0.05). This study challenges the validity of applying an equine model to the radiological anatomy of donkey feet. Hence, the diagnosis of anatomical change cannot be based on baseline data previously given for the horse and guidelines should be revised accordingly for the donkey. This study provides an objective basis for the identification of anatomical change associated with laminitis in donkey feet.

Developmental Changes of Mechanics Measured in the Gerbil Cochlea

This report describes stiffness and best frequency measurements obtained in vitro from the basilar membrane of the gerbil cochlea at the onset of hearing, during hearing maturation, and after hearing has matured. Our stiffness data constitute the first direct experimental evidence of developmental stiffness changes in the basal and middle turns. Stiffness changes by a factor of 5.5 in the basal turn between postnatal day 11 and adult, and the difference from adult is statistically significant for all ages measured up to postnatal day 16. For the middle turn, stiffness changes by a factor of 1.6 between postnatal day 11 and adult. Whereas for postnatal day 12 and beyond there is no statistically significant difference from adult, our data suggest that there may be a significant difference of stiffness between day 11 and adult in the middle turn. For the basal turn, our motion measurements confirm a passive component to the developmental best frequency shift. For the middle turn, changes in best frequency are not statistically significant. Best frequency was determined by stimulating the tissue at audio frequencies with a glass paddle and measuring motion with a computer-based imaging system. Tissue stiffness was measured with a piezoelectric-based sensor system. Tissue stiffness changes have previously been postulated to contribute to the best frequency shift observed in the cochlear base. Incorporating our data into a simple spring-mass resonance model demonstrates that our experimentally measured stiffness change can account for the change of best frequency. These results suggest that a stiffness change is, in fact, a critical component of the best frequency shift observed in the basal turn of the gerbil cochlea after the onset of hearing.

Computer-based integrated imaging using normalized cross-correlation for resolution enhancement

A computer-based integrated imaging system (CIIS) using normalized cross correlation (NCC) for resolution enhancement is proposed to extract accurate location data of 3-D objects. Elemental images (EI) of the target and reference objects are picked up by lenslet arrays, and then target and reference plane images with enhanced resolution are reconstructed at the output plane by using the CIIS technique. Through cross correlations between the reconstructed reference and target plane images, 3-D location data of the target objects in a scene can then be robustly extracted. As a result of our experiments, we see that the proposed correlation scheme provides good discrimination and detection performance for 3-D object recognition.

Design and Implementation of a Calibrated Store and Forward Imaging System for Teledermatology

The paper presents a computer-based imaging system aiming to support telemedicine examination sessions in dermatology. Many studies have proved the inadequacy of general practitioners to diagnose successfully common dermatological diseases; some of them may prove fatal if not diagnosed at their early stages (e.g., melanoma). Thus the need for telemedicine systems customized for dermatology becomes obvious for distant rural areas, where dermatological care is usually provided by general doctors. We treat technological issues such as image acquisition, camera calibration, illumination, data transmission, and data compression, and propose a store and forward architecture for image transmission. We also include a study of the effect that image compression quality factor has in the diagnostic value of the skin digital images, along with some initial results and conclusions from the pilot use of the system.

Performance evaluation of a hand-held, semiconductor (CdZnTe)-based gamma camera.

We have designed and developed a small field of view gamma camera, the eZ SCOPE, based on use of a CdZnTe semiconductor. This device utilises proprietary signal processing technology and an interface to a computer-based imaging system. The purpose of this study was to evaluate the performance of the eZ scope in comparison with currently employed gamma camera technology. The detector is a single wafer of 5-mm-thick CdZnTe that is divided into a 16x16 array (256 pixels). The sensitive area of the detector is a square of dimension 3.2 cm. Two parallel-hole collimators are provided with the system and have a matching (256 hole) pattern to the CdZnTe detector array: a low-energy, high-resolution parallel-hole (LEHR) collimator fabricated of lead and a low-energy, high-sensitivity parallel-hole (LEHS) collimator fabricated of tungsten. Performance measurements and the data analysis were done according to the procedures of the NEMA standard. We also studied the long-term stability of the system with continuous use and variations in ambient temperature. Results were as follows. INTRINSIC ENERGY RESOLUTION: 8.6% FWHM at 141 keV.LINEARITY: There was excellent linearity between the observed photopeaks and the known gamma ray energies for the given isotopes. INTRINSIC SYSTEM UNIFORMITY: For the central field of view, the integral uniformity and the differential uniformity were, respectively, 1.6% and 1.3% with the LEHR collimator and 1.9% and 1.2% with the LEHS collimator. SYSTEM SPATIAL RESOLUTION: The FWHM measurements made at the surface of the collimator were 2.2 mm (LEHR) and 2.9 mm (LEHS).CONTRAST TEST: The average S/N ratios (i.e. counts in the irradiated pixel divided by counts in the surrounding pixels) for the inner ring pixels (8)/outer ring pixels (16) using the LEHS collimator and LEHR collimator were 3.2%/0.2% and 3.7%/0.3%, respectively. COUNT RATE CHARACTERISTICS: We could not determine the maximum count rate and the 20% loss count rate from these data because the plateau was not reached while using the solutions measured. SYSTEM SENSITIVITY: The average acquisitions were 11,052 cpm/MBq (LEHR) and 28,590 cpm/MBq (LEHS). TEMPERATURE DEPENDENCE: The system displayed minimum corresponding shift in cps with temperature changes in the measured temperature range. We designed and developed a semiconductor-based gamma camera using CdZnTe. The basic performance of this camera compares favourably with the existing gamma camera technology that is deployed in the medical field today. The most significant differences include the spatial resolution, sensitivity, high count rate characteristics and energy resolution. We believe that this device will be of value for a number of clinical applications including sentinel node detection and radiopharmaceutical-guided surgery.

Interferometric oil-spill detection system

An automatic, oil-spill-detection system, which employs thin-film and wavefront-splitting interference techniques to determines the existence of surface oil or oil drops in water is disclosed. Two independent automatic, decision-making systems are disclosed, which provide a reliable means for oil spillage detection. A computer code and a image extraction system are employed to discern and monitor the interference fringes generated from oil slicks. The computer-based imaging system can be further replaced by a compact and low-cost imaging circuit that functions reliably in a buoy with relatively low power consumption.

Exposure assessment for a large epidemiological study of aircraft manufacturing workers.

Methods were developed to assess exposure to a wide variety of chemicals for nearly 80,000 workers involved in manufacturing aircraft since 1928. The facilities, now closed, consisted of four major plants, over 200 buildings, and a changing workforce during 60 years of operation. To access chemical exposures by specific jobs and calendar years, we reviewed complete work histories, examined detailed job descriptions available going back to 1940, interviewed long-term employees, conducted walk-through visits of aircraft manufacturing plants, reviewed comprehensive environmental assessment reports and industrial hygiene surveys on the facilities, and built on experience gained in previous studies of the aircraft industry. Using computer-based imaging systems, we examined and evaluated the complete work histories found on service record cards for the cohort and abstracted detailed information on all jobs held among the factory workers who had been employed for at least one year. Jobs were classified into one of three exposure categories related to the use of specific chemicals: routine, intermittent, and none, and these classifications were subsequently used in the epidemiological analyses. The approach to exposure assessment began with the most general categorization of employees (i.e., all workers) and then became progressively more specific, that is, factor workers, job families (similar activities), job titles, and jobs with chemical usage (exposure potential). Because exposure surveys were limited or absent during the early years of plant operations, we did not assign quantitative measures of exposure to individual job activities. Instead, we used as our exposure metric, the length of time spent in jobs with potential exposure to the chemical. Important occupational exposures included chromate-containing compounds such as used in paint primers, trichloroethylene and perchloroethylene used as vapor-state degreasing solvents, and a broad range of other solvents.

Neuroprotective effects of basic fibroblast growth factor following spinal cord contusion injury in the rat.

Cytokines and neurotrophic factors have been implicated in the pathophysiology of injury to the central nervous system. While some cytokines are considered pro-inflammatory, other factors promote neuronal growth and survival. The present study investigated the neuroprotective effects of interleukins 1 (IL-1), 4 (IL-4), and 6 (IL-6), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF), and basic fibroblast growth factor (bFGF) in a contusion model of spinal cord injury. Female Sprague-Dawley rats (n = 55) sustained a 10-g weight-drop injury to the lower thoracic spinal cord (T10) from a height of 12.5 mm using the NYU impactor. A micro-infusion system (Alzet minipump) was used to continuously deliver drugs or vehicle directly into the epicenter of the contused spinal cord starting 1 or three h postinjury. At the end of 7 days, animals were perfused and the cords removed for histopathological analysis. Longitudinal serial sections were cut on a freezing microtome and stained with cresyl violet. Areas of central necrosis, partial preservation, and total zone of tissue injury were identified and traced by an independent reviewer using a computer based imaging system. The mean total zone of injury in five animals receiving vehicle infusion was 18.04+/-4.20 mm3. The mean zone of partial preservation in these animals was 16.46+/-3.32 mm. Basic fibroblast growth factor reduced the total zone of injury by 33% [p<0.01, least significant difference (LSD) of Fisher] in five animals and the zone of partial preservation by 32% (p<0.01, LSD of Fisher) when compared to controls. There were trends toward reduction in total zone of injury and zone of partial preservation in rats treated with IL-4, CNTF, and NGF versus vehicle; however, none of these reached statistical significance. No significant differences were observed between animals receiving vehicle versus bFGF treatment commencing 3 h after injury. These data demonstrate that the continuous intramedullary infusion of bFGF initiated one hour after moderate contusion injury of the spinal cord significantly reduces the total zone of injury and the zone of partial preservation. These results support the further investigation and possible future clinical application of bFGF in the treatment of acute spinal cord contusion injury.

Goblet cell degranulation after antigen challenge in sensitized guinea pigs. Role of neutrophils.

Mucus hypersecretion is a common characteristic of asthma. Acute severe asthma is often associated with neutrophilic infiltration into airways. Neutrophils contain elastase, a potent secretagogue in airways. Therefore, we hypothesized that instillation of ovalbumin in sensitized guinea pigs causes goblet cell secretion by releasing elastase from recruited neutrophils. When we instilled ovalbumin into the trachea of ovalbumin-sensitized guinea pigs, early recruitment of neutrophils identified by 3,3'- diaminobenzidine staining, and goblet cell degranulation measured with a semiautomatic computer-based imaging system occurred. The Leumedin NPC 15669 (a drug that inhibits leukocyte recruitment) and an antibody to intercellular adhesion molecule-1 (ICAM-1) both prevented neutrophil recruitment and goblet cell degranulation, implicating leukocytes in the response. Using immunofluorescence we showed that the leukocytes recruited early after antigen challenge were CD-16-positive, implicating neutrophils. Pretreatment with the selective neutrophil elastase inhibitor ICI 200,355 also prevented ovalbumin-induced goblet cell degranulation, implicating elastase. We conclude that ovalbumin-induced goblet cell degranulation is due to neutrophil recruitment and elastase release.

Characterizing Fabric Pilling by Using Image-analysis Techniques. Part II: Comparison with Visual Pill Ratings

Pilling was evaluated on 122 solid-shade fabrics in two ways: by a subjective visual rating with ASTM photographic standards and by objective image analysis by using a computer-based imaging system developed specifically for pilling analysis. Pilling features evaluated by image analysis were: the total number, total area, and total volume of pills present; coefficients of variation of distributions of pill size, shape, orientation angle, and contrast; and the uniformity of pill spatial distribution on the fabric. Relationships between human-based visual ratings and objectively measured pill features were explored.

Overview of imaging science.

The traditional disciplines of science are grounded in the observation and measurement of object properties. Recent advances in digital computer technology have spawned numerous computer-based imaging systems that extend the range of observation and measurement into realms that would otherwise be inaccessible. More importantly, the same set of principles, concepts, strategies, and methods may be used to address the generic issues involved in the production and use of all digitized images. Recognition of this fact is giving rise to the new discipline of imaging science, with its own intellectual agenda.

An automatic monitoring system for epithelial cell height

This paper describes an automatic method to measure cell height (h) of epithelia grown as monolayers on transparent filter supports. Tissues are mounted in an Ussing-type chamber enabling solution exchange on both sides. The apical and basal side of the epithelial cells are marked with fluorescent beads. The image of the fluospheres is captured with a video camera and processed by a computer-based video imaging system. One basal reference bead in a gelatin layer on the filter support and up to three beads attached at the apical surface are used to monitor changes in cell height of three cells simultaneously. The focusing of the microbeads is done automatically by moving the objective with a piezoelectric device mounted on the nosepiece of the microscope. The algorithm for locating the bead is based on the changes in fluorescent light intensity emitted by the fluospheres. The method has an accuracy higher than 0.1 micron and a time resolution as low as 6 s if measurements are restricted to one bead at the apical side. The method was tested on artificial model systems and used to measure volume changes in renal cultured epithelia (A6) after exposing the serosal surface to hypotonic solutions and replacing cell-impermeable sucrose by an organic compound (glycerol) with a smaller reflection coefficient. Serosal hypotonicity elicited a rapid volume increase followed by regulatory volume decrease, whereas the organic compound replacement caused a steady increase in cell volume.

The Use of Digitized Port Films in Assessing New Treatment Modalities

An inexpensive computer-based imaging system has been used to compare simulator and portal radiographs. The films were digitized, normalized, and then overlaid for measurement. In a test group of patients, a new treatment protocol for pelvis irradiation was evaluated using this technique. For 90% of the patients, the average error was found to be smaller than 5 mm, and there were no field placement errors greater than 1 cm.

Microcomputer Image Processing for Burn Patients

A computer-based system was developed to handle information and images in a clinical setting. The system is based on an 80286 AT computer, the topology of which includes a 16-bit color image capture/display graphics adapter and a 256 gray scale 8-bit digital image analysis processor. Using its color capabilities, we have created a picture database of patients' injuries, radiographs, and other relevant clinical data. The computer-based imaging system allows instant access to this information and minimizes subjective evaluation, making comparison of and follow-up of treatments more objective. The image analysis components permit digital characterization of the burn wound, enhancing our ability to quantitatively evaluate wound size, contracture, graft take, and re-epithelialization. This is a cost-effective method of handling information and images in the clinical setting as well as an effective research and teaching tool that facilitates management and follow-up care of the patient with burns.

Impact of image size on effectiveness of digital imaging systems

Radiologists detect small diagnostic signals in radiographic film images by altering the distance between the eye and the image, effectively zooming in on a particular detail. Details thus enlarged are more perceptible to the viewer. Considering that conventional film images are nearly life-size, the potential for increasing the detection of small signals in this manner is high. Digital images, however, presented in video format are usually smaller than life-size, sometimes more than 50% smaller. While local enlargements using computer-based imaging systems are extremely useful, the radiologist cannot examine a whole, life-size image. The importance of the latter in the diagnostic process is revealed in detection studies using the same images of a chest phantom with small nodular inclusions, in different size formats. A clear positive correlation exists between overall image size and the detection of signals that are of a diagnostically-relevant size. While it is widely accepted that image fidelity is an important determinant in the clinical acceptability of digital radiography, digital image displays should also be large enough to display life-size images.

Image processing for the rest of us: The potential utility of inexpensive computerized image analysis in clinical pathology and radiology

Recent progress in computer technology in both hardware and software, combined with marked cost reductions, have placed quantitatively accurate video densitometry systems within the reach of the individual clinician, biomedical researcher, and community hospital. While much of the attention generated by advances in image processing has focussed on larger scale procedures, such as CAT, chemical shift, and positron emission tomography, important applications can be found for considerably more modest systems. In this article, we discuss three such applications of DUMAS, a personal computer-based imaging system developed by the Image Processing Center at Drexel University. A potential technique for quantifying numbers of estrogen receptors in tumorous breast tissue samples as a predictor of patient responsiveness to hormonal therapy is described first, along with possible sources of error. The second application, also related to clinical pathology and cancer, outlines methods for relating changes in nuclear and cell morphology to the diagnosis of Sezary Cell Syndrome. The utility of binary image filtering methods in the classification of cell types is discussed. The third application involves the development of a semi-automatic procedure for the determination of vessel diameter in arteriograms. A detailed description of the optimization and curve-fitting algorithms is provided along with preliminary test results comparing various approaches. The need for user demand to fuel research and development in small-scale imaging systems is also discussed.