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Interactive knee cartilage extraction using efficient segmentation software: data from the osteoarthritis initiative

Gan HS, Tan TS, Wong LX, Tham WK, Sayuti KA, Abdul Karim AH, et al.

Biomed Mater Eng, 2014;24(6):3145-57.
PMID: 25227024 DOI: 10.3233/BME-141137

In medical image segmentation, manual segmentation is considered both labor- and time-intensive while automated segmentation often fails to segment anatomically intricate structure accordingly. Interactive segmentation can tackle shortcomings reported by previous segmentation approaches through user intervention. To better reflect user intention, development of suitable editing functions is critical. In this paper, we propose an interactive knee cartilage extraction software that covers three important features: intuitiveness, speed, and convenience. The segmentation is performed using multi-label random walks algorithm. Our segmentation software is simple to use, intuitive to normal and osteoarthritic image segmentation and efficient using only two third of manual segmentation's time. Future works will extend this software to three dimensional segmentation and quantitative analysis.

Matched MeSH terms: Image Enhancement/methods*
THE CONSISTENCY OF EXPOSURE INDICATOR VALUES IN DIGITAL RADIOGRAPHY SYSTEMS

Jamil A, Mohd MI, Zain NM

Radiat Prot Dosimetry, 2018 Dec 01;182(4):413-418.
PMID: 29767799 DOI: 10.1093/rpd/ncy082

After years of establishment of computed radiography (CR) and digital radiography (DR), manufacturers have introduced exposure indicator/index (EI) as a feedback mechanism for patient dose. However, EI consistency is uncertain for CR. Most manufacturers recommended EI values in a range of numbers for all examination, instead of giving the exact range for a specific body part, raising a concern of inappropriate exposure given to the patient in clinical practice. The aims of this study were to investigate the EI consistency in DR systems produced in constant exposure parameters and clinical condition, and to determine the interaction between the anatomical part and EI. A phantom study of skull, chest, abdomen and hand was carried out and four systems were used for comparison-Fuji CR, Carestream CR, Siemens DR and Carestream DR. For each projection, the phantom positioning and exposure parameters were set according to the standard clinical practice. All exposure parameters and clinical conditions were kept constant. Twenty (20) exposures were taken for each projection and the EI was recorded. Findings showed that EI is not consistent in DR systems despite constant exposure parameters and clinical condition except in Siemens DR, through skull examination. Statistical analysis showed a significant interaction between anatomical parts and EI values (P < 0.05). EI alone was proven to be less reliable to provide technologist a correct feedback on exposure level. The interaction between anatomical parts and EI values intensifies the need for an anatomical-specific EI values set by all manufacturers for accurate feedback on the exposure parameters used and the detector entrance dose.

Matched MeSH terms: Radiographic Image Enhancement/instrumentation*; Radiographic Image Enhancement/standards*
Fulltext Radiographic imaging of steel oval lock carabiner by using computed radiography: a pilot study

Nadzirah Mohamad Radzi, Zafri Azran Abdul Majid

International Journal of Allied Health Sciences, 2018;2(2):310-318.
MyJurnal

Carabiner is one of Personal Protective Equipment (PPE), which is used to protect the users from hazards by reducing any chance of serious injury. Thus, it is very important to detect even a small
defect on the component before it becomes worse that could give harm to the users. The aim of this paper is to find out the appropriate imaging technical factors of steel carabiner by using computed radiography (CR). Methods: Radiographic images of carabiner were obtained by manipulating the values of kVp and mAs with respect to contrast and density. A preliminary study was carried out to determine the exposure factor combination in order to produce perceptible visual quality of radiographic images. Positioning techniques applied in this study were whole view (open-gate and close-gate position) and screw view (open-gate and close-gate position). An assessor was invited to evaluate the radiographs by using Image Quality Criteria Scoring (ICS) adapted from European Guidelines on Quality Criteria for Diagnostic Radiographic Images. Results: Findings showed that the optimum values of kVp and mAs in imaging whole view (open-gate and close-gate) carabiner were 133 kVp and 28 mAs while, for screw view (opengate and close-gate) the range of kVp and mAs preferred were 121 kVp to 133 kVp and 28 mAs to 36 mAs respectively. Conclusion: This study has found that the use of medical CR to expose metal steel such as
carabiner is accepted. By manipulating the imaging parameters, CR can produce a good quality image of carabiner.

Matched MeSH terms: Radiographic Image Enhancement
Digital radiographic image enhancement for weld defect detection using smoothing and morphological transformations

Suhaila Abdul Halim, Arsmah Ibrahim, Yupiter Harangan Prasada Manurung

Scientific Research Journal, 2012;9(1):15-27.
MyJurnal

Accurate inspection of welded materials is important in relation to achieve acceptable standards. Radiography, a non-destructive test method, is commonly used to evaluate the internal condition of a material with respect to defect detection. The presence of noise in low resolution of radiographic images significantly complicates analysis; therefore attaining higher quality radiographic images makes defect detection more readily achievable. This paper presents a study pertaining to the quality enhancement of radiographic images with respect to different types of defects. A series of digital radiographic weld flaw images were smoothed using multiple smoothing techniques to remove inherent noise followed by top and bottom hat morphological transformations. Image quality was evaluated quantitatively with respect to SNR, PSNR and MAE. The results indicate that smoothing enhances the quality of radiographic images, thereby promoting defect detection with the respect to original radiographic images.

Matched MeSH terms: Radiographic Image Enhancement
Fulltext Medical image visual appearance improvement using bihistogram Bezier curve contrast enhancement: data from the Osteoarthritis Initiative

Gan HS, Swee TT, Abdul Karim AH, Sayuti KA, Abdul Kadir MR, Tham WK, et al.

ScientificWorldJournal, 2014;2014:294104.
PMID: 24977191 DOI: 10.1155/2014/294104

Well-defined image can assist user to identify region of interest during segmentation. However, complex medical image is usually characterized by poor tissue contrast and low background luminance. The contrast improvement can lift image visual quality, but the fundamental contrast enhancement methods often overlook the sudden jump problem. In this work, the proposed bihistogram Bezier curve contrast enhancement introduces the concept of "adequate contrast enhancement" to overcome sudden jump problem in knee magnetic resonance image. Since every image produces its own intensity distribution, the adequate contrast enhancement checks on the image's maximum intensity distortion and uses intensity discrepancy reduction to generate Bezier transform curve. The proposed method improves tissue contrast and preserves pertinent knee features without compromising natural image appearance. Besides, statistical results from Fisher's Least Significant Difference test and the Duncan test have consistently indicated that the proposed method outperforms fundamental contrast enhancement methods to exalt image visual quality. As the study is limited to relatively small image database, future works will include a larger dataset with osteoarthritic images to assess the clinical effectiveness of the proposed method to facilitate the image inspection.

Matched MeSH terms: Image Enhancement/methods*
Education and imaging. Hepatobiliary and pancreatic: A huge liver paraganglioma

Koh PS, Koong JK, Westerhout CJ, Yoong BK

J Gastroenterol Hepatol, 2013 Jul;28(7):1075.
PMID: 23782121 DOI: 10.1111/jgh.12254
Matched MeSH terms: Radiographic Image Enhancement
A comparative study of computed radiography-based mammography using digital phosphor storage plate and full field digital mammography

Chelliah KK, Tamanang S, Bt Elias LS, Ying KY

Indian J Med Sci, 2013 11 2;67(1-2):23-8.
PMID: 24178338

BACKGROUND: Two digital mammography systems, based on different physical concepts, have been introduced in the last few years namely the full-field digital mammography (FFDM) system and computed radiography-based mammography using digital storage phosphor plate (DSPM).
AIMS: The objective of this study was to compare the image quality for DSPM and FFDM using a grading scale based on previously published articles.
MATERIALS AND METHODS: This comparative diagnostic study was done for 5-month duration at the Breast Clinic. The system used was the Lorad Selenia FFDM system and the Mammomat 3000 Nova DSPM system. The craniocaudal and mediolateral oblique projections were done on both breast on 58 asymptomatic women using both DSPM and FFDM. The mammograms were evaluated for eight criteria of image quality: Tissue coverage, compression, exposure, contrast, resolution, noise, artifact, and sharpness by two independent radiologists.
STATISTICAL ANALYSIS: Wilcoxon Signed Rank Test and Weighted Kappa.
RESULTS: FFDM was rated significantly better (P < 0.05) for five aspects: Tissue coverage, compression, contrast, exposure, and resolution and equal to DSPM for sharpness, noise, and artifact.
CONCLUSION: FFDM was superior in five aspects and equal to DSPM for three aspects of image quality.

Matched MeSH terms: Radiographic Image Enhancement/instrumentation; Radiographic Image Enhancement/methods*
Brain early infarct detection using gamma correction extreme-level eliminating with weighting distribution

Teh V, Sim KS, Wong EK

Scanning, 2016 Nov;38(6):842-856.
PMID: 27302216 DOI: 10.1002/sca.21334

According to the statistic from World Health Organization (WHO), stroke is one of the major causes of death globally. Computed tomography (CT) scan is one of the main medical diagnosis system used for diagnosis of ischemic stroke. CT scan provides brain images in Digital Imaging and Communication in Medicine (DICOM) format. The presentation of CT brain images is mainly relied on the window setting (window center and window width), which converts an image from DICOM format into normal grayscale format. Nevertheless, the ordinary window parameter could not deliver a proper contrast on CT brain images for ischemic stroke detection. In this paper, a new proposed method namely gamma correction extreme-level eliminating with weighting distribution (GCELEWD) is implemented to improve the contrast on CT brain images. GCELEWD is capable of highlighting the hypodense region for diagnosis of ischemic stroke. The performance of this new proposed technique, GCELEWD, is compared with four of the existing contrast enhancement technique such as brightness preserving bi-histogram equalization (BBHE), dualistic sub-image histogram equalization (DSIHE), extreme-level eliminating histogram equalization (ELEHE), and adaptive gamma correction with weighting distribution (AGCWD). GCELEWD shows better visualization for ischemic stroke detection and higher values with image quality assessment (IQA) module. SCANNING 38:842-856, 2016. © 2016 Wiley Periodicals, Inc.

Matched MeSH terms: Radiographic Image Enhancement
Brain white and gray matter anatomy of MRI segmentation based on tissue evaluation

Salih QA, Ramli AR, Mahmud R, Wirza R

MedGenMed, 2005;7(2):1.
PMID: 16369380

Different approaches to gray and white matter measurements in magnetic resonance imaging (MRI) have been studied. For clinical use, the estimated values must be reliable and accurate when, unfortunately, many techniques fail on these criteria in an unrestricted clinical environment. A recent method for tissue clusterization in MRI analysis has the advantage of great simplicity, and it takes the account of partial volume effects. In this study, we will evaluate the intensity of MR sequences known as T1-weighted images in an axial sliced section. Intensity group clustering algorithms are proposed to achieve further diagnosis for brain MRI, which has been hardly studied. Subjective study has been suggested to evaluate the clustering group intensity in order to obtain the best diagnosis as well as better detection for the suspected cases. This technique makes use of image tissue biases of intensity value pixels to provide 2 regions of interest as techniques. Moreover, the original mathematic solution could still be used with a specific set of modern sequences. There are many advantages to generalize the solution, which give far more scope for application and greater accuracy.

Matched MeSH terms: Image Enhancement/methods*
Fulltext Multipurpose contrast enhancement on epiphyseal plates and ossification centers for bone age assessment

Chai HY, Swee TT, Seng GH, Wee LK

Biomed Eng Online, 2013;12:27.
PMID: 23565999 DOI: 10.1186/1475-925X-12-27

The high variations of background luminance, low contrast and excessively enhanced contrast of hand bone radiograph often impede the bone age assessment rating system in evaluating the degree of epiphyseal plates and ossification centers development. The Global Histogram equalization (GHE) has been the most frequently adopted image contrast enhancement technique but the performance is not satisfying. A brightness and detail preserving histogram equalization method with good contrast enhancement effect has been a goal of much recent research in histogram equalization. Nevertheless, producing a well-balanced histogram equalized radiograph in terms of its brightness preservation, detail preservation and contrast enhancement is deemed to be a daunting task.

Matched MeSH terms: Image Enhancement/methods*
Fulltext Comparison studies of resolution and noise properties between drum type and laser type film digitization systems

Khairul Anuar Mohd Salleh, Ab. Razak Hamzah, Wan Muhammad Saridan Wan Hassan

Journal of Nuclear and Related Technologies, 2008;2008(2):35-45.
MyJurnal

Developments of computer technology and image processing have shifted conventional industrial radiography application to industrial digital radiography (IDR) system. In this study, two types of IDR modules for non destructive testing (NDT), namely drum- and laser- type film digitizer with 50 μm pixel pitch have been evaluated for NDT applications. The modulation transfer function (MTF) and noise power spectrum (NPS) measurement were adapted to evaluate the image quality of IDR images. Results shown the averaged MTF for drum- and laser- type film digitizer at 20% modulation were 6.15 cycles/mm and 6.55 cycles/mm respectively. For NPS measurement and calculation, the result obtained shows that drum type film digitizer produced higher noise then laser type film digitizer. The study shows that the laser type film digitizer is the best system to be used for film digitization purposes because the MTF result shows that it modulates better than drum type and has the lowest and stable NPS.

Matched MeSH terms: Radiographic Image Enhancement
Mixed lagrange time delay estimation autoregressive Wiener filter application for real-time SEM image enhancement

Sim KS, Law KK, Tso CP

Microsc Res Tech, 2007 Nov;70(11):919-27.
PMID: 17661362

A new filter is developed for the enhancement of scanning electron microscope (SEM) images. A mixed Lagrange time delay estimation auto-regression (MLTDEAR)-based interpolator is used to provide an estimate of noise variance to a standard Wiener filter. A variety of images are captured and the performance of the filter is shown to surpass the conventional noise filters. As all the information required for processing is extracted from a single image, this method is not constrained by image registration requirements and thus can be applied in real-time in cases where specimen drift is presented in the SEM image.

Matched MeSH terms: Image Enhancement*
A contrast stretching bilateral closing top-hat Otsu threshold technique for crack detection in images

Sim KS, Kho YY, Tso CP, Nia ME, Ting HY

Scanning, 2013 Mar-Apr;35(2):75-87.
PMID: 22777599 DOI: 10.1002/sca.21037

Detection of cracks from stainless steel pipe images is done using contrast stretching technique. The technique is based on an image filter technique through mathematical morphology that can expose the cracks. The cracks are highlighted and noise removal is done efficiently while still retaining the edges. An automated crack detection system with a camera platform has been successfully implemented. We compare crack extraction in terms of quality measures with those of Otsu's threshold technique and the another technique (Iyer and Sinha, 2005). The algorithm shown is able to achieve good results and perform better than these other techniques.

Matched MeSH terms: Image Enhancement
Reducing charging effects in scanning electron microscope images by Rayleigh contrast stretching method (RCS)

Wan Ismail WZ, Sim KS, Tso CP, Ting HY

Scanning, 2011 Jul-Aug;33(4):233-51.
PMID: 21611953 DOI: 10.1002/sca.20237

To reduce undesirable charging effects in scanning electron microscope images, Rayleigh contrast stretching is developed and employed. First, re-scaling is performed on the input image histograms with Rayleigh algorithm. Then, contrast stretching or contrast adjustment is implemented to improve the images while reducing the contrast charging artifacts. This technique has been compared to some existing histogram equalization (HE) extension techniques: recursive sub-image HE, contrast stretching dynamic HE, multipeak HE and recursive mean separate HE. Other post processing methods, such as wavelet approach, spatial filtering, and exponential contrast stretching, are compared as well. Overall, the proposed method produces better image compensation in reducing charging artifacts.

Matched MeSH terms: Image Enhancement/methods*
Tooth mineralization stages as a diagnostic tool for assessment of skeletal maturity

Surendran S, Thomas E

Am J Orthod Dentofacial Orthop, 2014 Jan;145(1):7-14.
PMID: 24373650 DOI: 10.1016/j.ajodo.2013.09.007

The objective of this study was to determine whether dental calcification can be used as a first-level diagnostic tool for assessment of skeletal maturity.

Matched MeSH terms: Radiographic Image Enhancement/methods
Fulltext Ultrasound-guided pericardiocentesis: a novel parasternal approach

Osman A, Wan Chuan T, Ab Rahman J, Via G, Tavazzi G

Eur J Emerg Med, 2018 Oct;25(5):322-327.
PMID: 28509710 DOI: 10.1097/MEJ.0000000000000471

OBJECTIVE: The aim of this study was to evaluate a novel pericardiocentesis technique using an in-plane parasternal medial-to-lateral approach with the use of a high-frequency probe in patients with cardiac tamponade.
BACKGROUND: Echocardiography is pivotal in the diagnosis of pericardial effusion and tamponade physiology. Ultrasound guidance for pericardiocentesis is currently considered the standard of care. Several approaches have been described recently, which differ mainly on the site of puncture (subxiphoid, apical, or parasternal). Although they share the use of low-frequency probes, there is absence of complete control of needle trajectory and real-time needle visualization. An in-plane and real-time technique has only been described anecdotally.
METHODS AND RESULTS: A retrospective analysis of 11 patients (63% men, mean age: 37.7±21.2 years) presenting with cardiac tamponade admitted to the tertiary-care emergency department and treated with parasternal medial-to-lateral in-plane pericardiocentesis was carried out. The underlying causes of cardiac tamponade were different among the population. All the pericardiocentesis were successfully performed in the emergency department, without complications, relieving the hemodynamic instability. The mean time taken to perform the eight-step procedure was 309±76.4 s, with no procedure-related complications.
CONCLUSION: The parasternal medial-to-lateral in-plane pericardiocentesis is a new technique theoretically free of complications and it enables real-time monitoring of needle trajectory. For the first time, a pericardiocentesis approach with a medial-to-lateral needle trajectory and real-time, in-plane, needle visualization was performed in a tamponade patient population.

Matched MeSH terms: Image Enhancement/methods*
A comparative study of X-ray pelvimetry and CT pelvimetry

Raman S, Samuel D, Suresh K

Aust N Z J Obstet Gynaecol, 1991 Aug;31(3):217-20.
PMID: 1804081

In this study 24 patients who had conventional erect lateral X-ray pelvimetry had a CT pelvimetry done after delivery to complete the pelvimetry views. The erect lateral pelvimetry was read independently by a Consultant Radiologist, Consultant Obstetrician and a Medical Officer training in Obstetrics and Gynaecology. Using CT pelvimetry as the 'gold standard' (as the error of measurement was known with the machine used) the 3 readings were compared. There was no statistical difference in the values suggesting that X-ray pelvimetry is comparable to CT pelvimetry. However CT pelvimetry is preferred, if available, because of the lower dose of radiation involved, more comfort for the patient and shorter time in performing the procedure. Measurements done are easily read directly from the CT console.

Matched MeSH terms: Radiographic Image Enhancement
Fulltext Optimization of exposure parameters in full field digital mammography using figure of merit. [Pengoptimuman parameter dedahan dalam mamografi digital medan penuh menggunakan rajah merit]

Laila Suryani Elias, Eng M, Ang W, Chelliah K, Abd Aziz Tajuddin, Arasaratnam S, et al.

Sains Malaysiana, 2010;39:299-303.

Mammography is used as a screening tool for early detection of breast cancer. However, the radiation dose used should be as low as possible to minimize any effects on asymptomatic woman while maintaining the diagnostic value of the image as mammography is done annually. This study was done to determine the optimum exposure parameter in exposure control mode (AEC) for two combinations of anode/filter which were molybdenum/molybdenum (Mo/Mo) and molybdenum/rhodium (Mo/Rh) using the Lorad Selenia digital mammography system at the Women’s Breast Clinic, National Cancer Society (NCS). A CIRS012A mammography research of phantom 4 cm thickness with 50% glandularity was exposed in the cranio-caudal projection. TLD 100H was used to measure the entrance surface air kerma (ESAK). The AGD values were then calculated from the ESAK values, incorporating three correction factors (g, c and s) according to Euref protocol. Image quality was evaluated using signal to noise ratio (SNR). Figure of Merit (FOM) which is the ratio of the square of SNR to the AGD shows that 30 kVp is the optimum exposure parameter for a 4 cm thickness phantom with the use of Mo/Rh and Mo/Mo anode/filter combination. Non-parametric Spearman correlation test showed a negative linear relationship between AGD and SNR with increasing tube voltage for both anode/filters.
Keywords: Average glandular dose; CIRS012A phantom; exposure; full field digital mammography
Study site: Women’s Breast Clinic, National Cancer Society (NCS), Kuala Lumpur, Malaysia

Matched MeSH terms: Radiographic Image Enhancement
Determination of skin repigmentation progression

Nugroho H, Fadzil MH, Yap VV, Norashikin S, Suraiya HH

Annu Int Conf IEEE Eng Med Biol Soc, 2007;2007:3442-5.
PMID: 18002737

In this paper, we describe an image processing scheme to analyze and determine areas of skin that have undergone repigmentation in particular, during the treatment of vitiligo. In vitiligo cases, areas of skin become pale or white due to the lack of skin pigment called melanin. Vitiligo treatment causes skin repigmentation resulting in a normal skin color. However, it is difficult to determine and quantify the amount of repigmentation visually during treatment because the repigmentation progress is slow and moreover changes in skin color can only be discerned over a longer time frame typically 6 months. Here, we develop a digital image analysis scheme that can identify and determine vitiligo skin areas and repigmentation progression on a shorter time period. The technique is based on principal component analysis and independent component analysis which converts the RGB skin image into a skin image that represent skin areas due to melanin and haemoglobin only, followed by segmentation process. Vitiligo skin lesions are identified as skin areas that lack melanin (non-melanin areas). In the initial studies of 4 patients, the method has been able to quantify repigmentation in vitiligo lesion. Hence it is now possible to determine repigmentation progression objectively and treatment efficacy on a shorter time cycle.

Matched MeSH terms: Image Enhancement/methods
Fulltext Realistic real-time outdoor rendering in augmented reality

Kolivand H, Sunar MS

PLoS One, 2014;9(9):e108334.
PMID: 25268480 DOI: 10.1371/journal.pone.0108334

Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems.

Matched MeSH terms: Image Enhancement/methods*

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