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Author: search.filters.author.Laothamatas, JirapornHas files: No

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    Axial loading during supine MRI for improved assessment of lumbar spine: comparison with standing MRI
    (2023-01-01)
    Charoensuk, Jarruwat
    ;
    Laothamatas, Jiraporn
    ;
    Sungkarat, Witaya
    ;
    Worapruekjaru, Ladawan
    ;
    Hooncharoen, Boonthida
    Background: There are no studies comparing the morphologic changes of lumbar spines between supine axial-loaded and 90° standing magnetic resonance imaging (MRI) examinations of patients with spinal stenosis. Purpose: To determine whether axial-loaded MRI using a compression device demonstrated similar morphology of intervertebral disc, dural sac, and spinal curvature as those detected by 90° standing MRI in individuals with suspected spinal stenosis. Material and Methods: A total of 54 individuals suspected of having spinal stenosis underwent both axial-loaded and standing MRI studies. The outcome measures included seven radiologic parameters of the lumbar spine: measures of the intervertebral disc (i.e. cross-sectional area [DA], disc height [DH], and anteroposterior distance [DAP]), dural sac (cross-sectional area [DCSA]), spinal curvature (i.e. lumbar lordosis [LL] and L1-L3-L5 angle [LA]), and total lumbar spine height (LH). Results: For agreement between the two methods, intraclass correlation coefficient (ICC) ≥ 0.8 was found for all seven radiologic parameters. Supine axial-loaded MRI underestimated LL but remained correlated (ICC = 0.83) with standing MRI. Minor differences between the two methods (≤5.0%) were observed in DA, DCSA, DAP, LA, and LH, while a major difference was observed in LL (8.1%). Conclusion: Using a compression device with the conventional supine MRI to simulate weight-bearing on the lumbar spine generated MRI morphology, which was strongly correlated with those from a standing MRI.
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    Lumbosacral spinal compression device with the use of a cushion back support in supine MRI
    (2021-08-01)
    Sungkarat, Witaya
    ;
    Laothamatas, Jiraporn
    ;
    Worapruekjaru, Ladawan
    ;
    Hooncharoen, Boonthida
    ;
    Charoensuk, Jarruwat
    Background: We hypothesized that axial-loaded magnetic resonance imaging (MRI), modified with the use of a cushion placed behind the lower back (i.e. BS-MRI method), would simulate the standing position more accurately than an axial-loaded MRI without a cushion back support (BS). Purpose: To determine whether the BS-MRI method demonstrated similar morphologies on intervertebral disc (IVD), dural sac, and spinal curvature as those detected on 90° standing MRIs in individuals with suspected spinal stenosis. Material and Methods: Twenty-five subjects underwent a BS-MRI, as well as axial-loaded and standing MRI studies. Outcome measures were four radiographic parameters of the lumbar spine: IVD height (DH); dural sac cross-sectional area (DCSA); and spinal curvature (i.e. lumbar lordosis [LL] and L1-L3-L5 angle [LA]). Results: Major differences (>5%) between standing MRI and BS-MRI methods were observed in DCSA, DH, and LL. Major differences between standing and axial loaded MRIs were observed only in DCSA and LA. Although BS-MRIs demonstrate an image of the lumbar spine curvature (i.e. LA) which is closer to that when standing than axial-loaded MRIs, it is likely to overestimate both narrowing of dural sac and extent of LL. Conclusion: Using a compression device with a BS to simulate weight-bearing on the lumbar spine is not recommended due to: (i) overestimation of the narrowing of the dural sac and extent of LL; and (ii) underestimation of loss of disc height. Supine axial-loading produced DCSA and DH which were strongly correlated with those detected with standing MRIs. Exceptions were that LL and LA were underestimated.
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    Axial-Loaded MRI Using a SpineMAC Device to Show Narrowing of Dural Sac and Disc Height in Lumbar Spinal Stenosis
    (2020-12-01)
    Sungkarat, Witaya
    ;
    Laothamatas, Jiraporn
    ;
    Worapruekjaru, Ladawan
    ;
    Hooncharoen, Boonthida
    ;
    Charoensuk, Jarruwat
    Background: A lumbosacral spinal compression device has been developed by the authors (SpineMAC) to simulate normal weight-bearing by axial-loading of the lumbar spine while the patient is in the supine position. Objective: To investigate the effect of axial loading using a SpineMAC device, on lumbar spine, spinal canal, and spine curvature, in subjects with suspected spinal stenosis. Materials and Methods: The present study was prospective cross-sectional study. Forty-five (21 males and 24 females) consecutive Thai adults underwent unloaded and axial-loaded supine magnetic resonance imaging (MRI) examinations of the lumbosacral spine. Radiographic parameters included cross-sectional area of disc (DA), cross-sectional area of dural sac (DCSA), disc height (DH), anterior to posterior distance of disc (DAP), L1-L3-L5 angle (LA), and lumbar lordosis (LL). Results: During the axial-loaded MRIs, the pathologic features of the lumbar spinal stenosis such as the disc bulging, nerve root compression, narrowing of the spinal canal, and the spinal neural foramina, were frequently observed in L4-L5 and L5-S1. Radiographic parameters differences of more than 5% between unloaded and axial-loaded supine MRIs were observed in DCSA and DH. Narrowing of the dural sac due to axial compression was observed at the L4-L5 level (8.1%), while loss of DH was found at both the L5-S1 (-7.9%) and the L4-L5 (-6.8%) levels. Axial compression only slightly affected the DA and DAP of the intervertebral discs with a difference of 5% or less. Furthermore, it rarely changed the spine curvature (LL and LA) of the subjects, with a difference of 2% or less. LL decreased during axial loading and may not correlate with the findings during normal standing position. Although the authors found greater DA and DAP values in male (p<0.001) and obese (p<0.05) subjects, changes of radiographic parameters with axial loading were otherwise not correlated with sex, age, or body mass index. Conclusion: An axial-loaded MRI, using a SpineMAC device, may be superior to conventional MRI when evaluating narrowing of the dural sac and disc height of patients.
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    Computational Fluid Dynamic (CFD) in Thai patient with Obstructive Sleep Apnea Syndrome (OSAS) - A case report: Comparative study between healthy and OSA subject
    (2012-12-01)
    Sarasaen, Chompunuch
    ;
    Bhongmakapat, Thongchai
    ;
    Hemtiwakorn, Khaisang
    ;
    Laothamatas, Jiraporn
    ;
    Pintavirooj, Chuchart
    In order to investigate flow characteristics in upper airway, this study focuses on applied Computational Fluid Dynamics (CFD) with Obstructive Sleep Apnea Syndrome (OSAS) base on Computed Tomography images. OSAS has been remarked in the several decades because of its disturbance and severity that leading to a serious morbidity and excess mortality in long-term consequences such as heart attack and strokes. Although numerous methods have been advocated for treatment an OSA syndrome, no single procedure employed effectively. To investigate the airflow behavior, three-dimensional airway models during tidal breathing has been performed in a patient with obstructive sleep apnea and one control. Segmentation was carried out from CT data initially. Then, the volumetric surface was performed by reverse engineering process and mesh generation was operated after that. Computational modeling for inspiration was operated by employing k-ω SST turbulence model. For comparison the airflow characteristics, streamline, velocity, pressure, and wall shear stress either of models were illustrated. For patient associated with OSA, Particularly in oropharynx region, velocity significantly increase and negative pressure greater than the control one because of narrower airway. Furthermore, WSS manifestly rises up in stricture area. In brief, The CFD analysis could be employed to evaluate the airflow in OSA patients as an alternative technique for diagnosis and treatment planning. ©2012 IEEE.