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  1. Bilgen M
    Australas Phys Eng Sci Med, 2010 Dec;33(4):357-66.
    PMID: 21110236 DOI: 10.1007/s13246-010-0039-z
    Homogenous strain analysis (HSA) was developed to evaluate regional cardiac function using tagged cine magnetic resonance images of heart. Current cardiac applications of HSA are however limited in accurately detecting tag intersections within the myocardial wall, producing consistent triangulation of tag cells throughout the image series and achieving optimal spatial resolution due to the large size of the triangles. To address these issues, this article introduces a harmonic phase (HARP) interference method. In principle, as in the standard HARP analysis, the method uses harmonic phases associated with the two of the four fundamental peaks in the spectrum of a tagged image. However, the phase associated with each peak is wrapped when estimated digitally. This article shows that special combination of wrapped phases results in an image with unique intensity pattern that can be exploited to automatically detect tag intersections and to produce reliable triangulation with regularly organized partitioning of the mesh for HSA. In addition, the method offers new opportunities and freedom for evaluating myocardial function when the power and angle of the complex filtered spectra are mathematically modified prior to computing the phase. For example, the triangular elements can be shifted spatially by changing the angle and/or their sizes can be reduced by changing the power. Interference patterns obtained under a variety of power and angle conditions were presented and specific features observed in the results were explained. Together, the advanced processing capabilities increase the power of HSA by making the analysis less prone to errors from human interactions. It also allows strain measurements at higher spatial resolution and multi-scale, thereby improving the display methods for better interpretation of the analysis results.
  2. Sani FM, Sarji SA, Bilgen M
    J Ultrasound Med, 2011 Jul;30(7):883-94.
    PMID: 21705720
    OBJECTIVES: The purpose of this study was to test the hypothesis that quantitative ultrasound properties of the calcaneus in Southeast Asian children treated for thalassemia have different characteristics than those of their healthy counterparts and thereby can be used for assessing the risk of osteoporosis.

    METHODS: Broadband ultrasound attenuation and the speed of sound were measured from groups of thalassemic and healthy children and compared with bone mineral density (BMD) estimated from dual-energy X-ray absorptiometry to determine intergroup and intragroup dependencies of the measurements and variations with differences in sex and anthropometric characteristics.

    RESULTS: Broadband ultrasound attenuation and speed of sound measurements were found to be independent of sex but dependent on age in the thalassemic children. Consistently, broadband ultrasound attenuation had lower values and the speed of sound had higher values compared with those of the healthy children in each age group. Broadband ultrasound attenuation correlated well with the speed of sound and also with age, weight, and height, but the speed of sound did not show an association with these parameters. Broadband ultrasound attenuation correlated moderately with BMD in the lumbar spine and whole body, but the corresponding association was much weaker for the speed of sound. In the thalassemic children, both broadband ultrasound attenuation and BMD increased with age as they grew older but not fast enough compared with the healthy children, and the risk of osteoporosis was greater at older ages.

    CONCLUSIONS: Calcaneal quantitative ultrasound may be used as a diagnostic screening tool for assessing the bone status in thalassemic Southeast Asian children and for deciding whether further dual-energy X-ray absorptiometry is needed, particularly in those who are at a greater risk for osteoporosis as identified by low body weight and height.

  3. Salama SM, Bilgen M, Al Rashdi AS, Abdulla MA
    PMID: 22988470 DOI: 10.1155/2012/137083
    Background. Experimental research in hepatology has focused on developing traditional medicines into potential pharmacological solutions aimed at protecting liver from cirrhosis. Along the same line, this study investigated the effects of ethanol-based extract from a traditional medicine plant Boesenbergia rotunda (BR) on liver cirrhosis. Methodology/Results. The BR extract was tested for toxicity on 3 groups of rats subjected to vehicle (10% Tween 20, 5 mL/kg) and 2g/kg and 5g/kg doses of the extract, respectively. Next, experiments were conducted on a rat model of cirrhosis induced by thioacetamide injection. The rats were divided into five groups and, respectively, administered orally with 10% Tween-20 (5 mL/kg) (normal control group), 10% Tween-20 (5 mL/kg) (cirrhosis control group), 50 mg/kg of silymarin (reference control group), and 250 mg/kg and 500 mg/kg of BR extract (experimental groups) daily for 8 weeks. The rats in normal group were intraperitoneally injected with sterile distilled water (1 mL/kg) 3 times/week, and those in the remaining groups were injected intraperitoneally with thioacetamide (200 mg/kg) thrice weekly. At the end of the 8 weeks, the animals were sacrificed and samples were collected for comprehensive histopathological, coagulation profile and biochemical evaluations. Also, the antioxidant activity of the BR extract was determined and compared with that of silymarin. Data from the acute toxicity tests showed that the extract was safe to use. Histological analysis of the livers of the rats in cirrhosis control group revealed uniform coarse granules on their surfaces, hepatocytic necrosis, and lymphocytes infiltration. But, the surfaces morphologically looked much smoother and the cell damage was much lesser in those livers from the normal control, silymarin and BR-treated groups. In the high-dose BR treatment group, the livers of the rats exhibited nearly normal looking lobular architecture, minimal inflammation, and minimal hepatocyte damage, the levels of the serum biomarkers and liver enzymes read nearly normal, and these results were all comparable to those observed or quantified from the normal and silymarin-treated groups. The BR extract had the antioxidant activity about half of what was recorded for silymarin. Conclusion. The progression of the liver cirrhosis can be intervened using the ethanol-based BR extract, and the liver's status quo of property, structure, and function can be preserved. This capability of the extract warrants further studies exploring the significance of its pharmacologic potential in successfully treating the liver cirrhosis in humans.
  4. Zourmand A, Mirhassani SM, Ting HN, Bux SI, Ng KH, Bilgen M, et al.
    Biomed Eng Online, 2014;13:103.
    PMID: 25060583 DOI: 10.1186/1475-925X-13-103
    The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.
  5. Latifi MH, Ganthel K, Rukmanikanthan S, Mansor A, Kamarul T, Bilgen M
    Biomed Eng Online, 2012;11:23.
    PMID: 22545650 DOI: 10.1186/1475-925X-11-23
    Effective fixation of fracture requires careful selection of a suitable implant to provide stability and durability. Implant with a feature of locking plate (LP) has been used widely for treating distal fractures in femur because of its favourable clinical outcome, but its potential in fixing proximal fractures in the subtrochancteric region has yet to be explored. Therefore, this comparative study was undertaken to demonstrate the merits of the LP implant in treating the subtrochancteric fracture by comparing its performance limits against those obtained with the more traditional implants; angle blade plate (ABP) and dynamic condylar screw plate (DCSP).
  6. Leong SS, Vijayananthan A, Yaakup NA, Shah N, Ng KH, Acharya UR, et al.
    Comput Biol Med, 2016 11 01;78:58-64.
    PMID: 27658262 DOI: 10.1016/j.compbiomed.2016.09.006
    OBJECTIVE: To determine the reproducibility of three-dimensional (3D) ultrasound (US) over two-dimensional (2D) US in characterizing atherosclerotic carotid plaques using inter- and intra-observer agreement metrics.

    METHODS: A Total of 51 patients with 105 carotid artery plaques were screened using 3D and 2D US probes attached to the same US scanner. Two independent observers characterized the plaques based on the morphological features namely echotexture, echogenicity and surface characteristics. The scores assigned to each morphological feature were used to determine intra- and inter-observer performance. The level of agreement was measured using Kappa coefficient.

    RESULTS: The first observer with 2D US showed fair (k=0.4-0.59) and very strong (k>0.8) with 3D US intra-observer agreements using three morphological features. The second observer indicated moderate strong (k=0.6-0.79) with 2D US and very strong with 3D US (k>0.8) intra-observer performances. Moderate strong (k=0.6-0.79) and very strong (k>0.8) inter-observer agreements were reported with 2D US and 3D US respectively. The results with 2D and 3D US were correlated 62% using only echotexture and 56% using surface morphology coupled with echogenicity. 3D US gave a lower score than 2D 71% of the time (p=0.005) in disagreement cases.

    CONCLUSION: High reproducibility in carotid plaque characterization was obtained using 3D US rather than 2D US. Hence, it can be a preferred imaging modality in routine or follow up plaque screening of patients with carotid artery disease.

  7. Leong CO, Liew YM, Bilgen M, Abdul Aziz YF, Chee KH, Chiam YK, et al.
    J Magn Reson Imaging, 2016 Jul 15.
    PMID: 27418150 DOI: 10.1002/jmri.25390
    To propose a cardiac motion tracking model that evaluates wall motion abnormality in postmyocardial infarction patients. Correlation between the motion parameter of the model and left ventricle (LV) function was also determined.
  8. Amin ZA, Bilgen M, Alshawsh MA, Ali HM, Hadi AH, Abdulla MA
    PMID: 22649471 DOI: 10.1155/2012/241583
    A preclinical study was performed to determine if the extract from Phyllanthus niruri (PN) plays a protective role against liver cirrhosis induced by thioacetamide (TAA) in rats. Initially, acute toxicity was tested and the results showed that the extract was benign when applied to healthy rats. Next, the therapeutic effect of the extract was investigated using five groups of rats: control, TAA, silymarin, and PN high dose and low dose groups. Significant differences were observed between the TAA group and the other groups regarding body and liver weights, liver biochemical parameters, total antioxidant capacity, lipid peroxidation, and oxidative stress enzyme levels. Gross visualization indicated coarse granules on the surface of the hepatotoxic rats' livers, in contrast to the smoother surface in the livers of the silymarin and PN-treated rats. Histopathological analysis revealed necrosis, lymphocytes infiltration in the centrilobular region, and fibrous connective tissue proliferation in the livers of the hepatotoxic rats. But, the livers of the treated rats had comparatively minimal inflammation and normal lobular architecture. Silymarin and PN treatments effectively restored these measurements closer to their normal levels. Progression of liver cirrhosis induced by TAA in rats can be intervened using the PN extract and these effects are comparable to those of silymarin.
  9. Salama SM, Ibrahim IAA, Shahzad N, Al-Ghamdi S, Ayoub N, AlRashdi AS, et al.
    APMIS, 2018 Sep;126(9):710-721.
    PMID: 30058214 DOI: 10.1111/apm.12878
    This experiment evaluated Panduratin A (PA), a chalcone isolated from Boesenbergia rotunda rhizomes, for its hepatoprotectivity. Rats were subjected to liver damage induced by intra-peritoneal injection of thioacetamide (TAA). PA was tested first for its acute toxicity and then administered by oral gavage at doses 5, 10, and 50 mg/kg to rats. At the end of the 8th week, livers from all rats were excised and evaluated ex vivo. Measurements included alkaline phosphatase (AP), alanine transaminase (ALT), aspartate transaminase (AST) and gamma-glutamyl transferase (GGT), serum platelet-derived growth factor (PDGF) and transforming growth factor (TGF-β1), and hepatic metalloproteinase enzyme (MMP-2) and its inhibitor extracellular matrix protein (TIMP-1). Oxidative stress was measured by liver malondialdehyde (MDA) and nitrotyrosine levels, urinary 8-hydroxy 2- deoxyguanosine (8-OH-dG), and hepatic antioxidant enzyme activities. The immunohistochemistry of TGF-β1 was additionally performed. PA revealed safe dose of 250 mg/kg on experimental rats and positive effect on the liver. The results suggested reduced hepatic stellate cells (HSCs) activity as verified from the attenuation of serum PDGF and TGF-β1, hepatic MMP-2 and TIMP-1, and oxidative stress. The extensive data altogether conclude that PA treatment could protect the liver from the progression of cirrhosis through a possible mechanism inhibiting HSCs activity.
  10. Jahanzad Z, Liew YM, Bilgen M, McLaughlin RA, Leong CO, Chee KH, et al.
    Phys Med Biol, 2015 May 21;60(10):4015-31.
    PMID: 25919317 DOI: 10.1088/0031-9155/60/10/4015
    A segmental two-parameter empirical deformable model is proposed for evaluating regional motion abnormality of the left ventricle. Short-axis tagged MRI scans were acquired from 10 healthy subjects and 10 postinfarct patients. Two motion parameters, contraction and rotation, were quantified for each cardiac segment by fitting the proposed model using a non-rigid registration algorithm. The accuracy in motion estimation was compared to a global model approach. Motion parameters extracted from patients were correlated to infarct transmurality assessed with delayed-contrast-enhanced MRI. The proposed segmental model allows markedly improved accuracy in regional motion analysis as compared to the global model for both subject groups (1.22-1.40 mm versus 2.31-2.55 mm error). By end-systole, all healthy segments experienced radial displacement by ~25-35% of the epicardial radius, whereas the 3 short-axis planes rotated differently (basal: 3.3°; mid:  -1° and apical:  -4.6°) to create a twisting motion. While systolic contraction showed clear correspondence to infarct transmurality, rotation was nonspecific to either infarct location or transmurality but could indicate the presence of functional abnormality. Regional contraction and rotation derived using this model could potentially aid in the assessment of severity of regional dysfunction of infarcted myocardium.
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