Browsing by Subject "Computed tomography"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Diagnostic accuracy of panoramic radiograph and MRI for detecting signs of TMJ degenerative joint disease
    (2016-07) Kaimal, Shanti
    Background: To determine the diagnostic accuracy of panoramic radiograph and magnetic resonance imaging (MRI) for detection of signs of temporomandibular joint (TMJ) degenerative joint disease (DJD). Methods: Panoramic radiographs, bilateral TMJ MRI and bilateral TMJ computed tomography (CT) were performed on 705 subjects. Three calibrated board-certified radiologists blinded to the subjects’ clinical findings interpreted all images. Assessment of diagnostic accuracy of panoramic radiographs and MRI for detecting signs of DJD was compared to the reference-standard diagnoses derived from the CTs. DJD was defined by the presence of subcortical cyst, surface erosion, osteophyte or generalized sclerosis. Target sensitivity and specificity were > 70% and > 95%, respectively. Results: For panoramic radiographs, sensitivity and specificity were: subcortical cysts - 14%, 100% respectively; erosion - 20%, 100% respectively; osteophyte - 12%, 100% respectively and generalized sclerosis - 33%, 100%, respectively. For MRI, sensitivity and specificity were: subcortical cysts - 32%, 100% respectively; erosion - 35%, 99% respectively; osteophyte 71%, 98% respectively and generalized sclerosis 50%, 100% respectively. For diagnosis of signs of DJD based on panoramic radiographs, radiologists’ inter-examiner reliability was slight (k=0.16), moderate (k=0.47) when using MRI and substantial with CT images (k=0.71). Conclusions: Panoramic radiographs and MRI had below target sensitivity but above target specificity in detecting all CT-depicted signs of DJD with the exception of detection of MRI-depicted osteophytes, which had adequate diagnostic accuracy. Practical Implications: Use of CT to diagnosis signs of TMJ DJD is recommended to address the false negatives that can occur with panoramic radiographs and MRI.
  • Thumbnail Image
    Item
    Is CT Angiography Right for You?
    (2009-05-06) Meyers, Jason
    Given the high sensitivity and negative predictive value of 64-slice CT angiography, a negative result can be used to effectively rule out CAD in the intermediate risk patient, while a positive result can identify those who need to proceed to traditional angiography.
  • Thumbnail Image
    Item
    Miniature Computer-Tomography-imaging-spectrometer.
    (2007-12) Wei, Zhou
    A novel design methodology for the miniature imaging spectrometer has been demonstrated. The Computer-Tomography detection scheme is applied because of its inherently large etendue and snap-shot function. As opposed to the traditional CTIS design that employs only one dispersive element to generate all different spectral and spatial information mixing, the idea of independent information collection and multiple-channel array structure is introduced. Based on this idea our design will not only achieve a very compact sensor structure for limited system aperture size, but also dramatically reduce the alignment and assembly difficulty compared with other micro imaging spectrometers. By combining diffractive, refractive and graded-index (GRIN) optics into single optical element, every information channel consists of three quarter-pitch GRIN lenses (diameter of 250um) with an on-axis dispersion imaging function. By rotating the information channel to arbitrary azimuthal directions along the optical axis, different dispersion mixing is introduced to the same object's image. This scheme provides the freedom of increasing information channels for higher spectral resolution. One miniature CTIS sensor was designed with 16 information channels in a 1mm x 1mm x 2mm cube. A single channel was fabricated and tested. A Focused-Ion-Beam Etch method was employed to directly fabricate the grating on the cylinder GRIN lens. A simple but efficient hyper-spectral information reconstruction algorithm was built up and successfully tested with NASA AVIRIS satellite hyperspectral data. The designed sensor performance was tested with different polychromatic objects.
  • Thumbnail Image
    Item
    Quantitative digital assessment of periapical healing.
    (2011-08) Wiswall, Jeffrey Herbert
    Abstract summary not available