Cone beam CT of the musculoskeletal system : clinical applications

Objectives: The aim of this pictorial review is to illustrate the use of CBCT in a broad spectrum of musculoskeletal disorders and to compare its diagnostic merit with other imaging modalities, such as conventional radiography (CR), Multidetector Computed Tomography (MDCT) and Magnetic Resonance Imaging. Background: Cone Beam Computed Tomography (CBCT) has been widely used for dental imaging for over two decades. Discussion: Current CBCT equipment allows use for imaging of various musculoskeletal applications. Because of its low cost and relatively low irradiation, CBCT may have an emergent role in making a more precise diagnosis, assessment of local extent and follow-up of fractures and dislocations of small bones and joints. Due to its exquisite high spatial resolution, CBCT in combination with arthrography may be the preferred technique for detection and local staging of cartilage lesions in small joints. Evaluation of degenerative joint disorders may be facilitated by CBCT compared to CR, particularly in those anatomical areas in which there is much superposition of adjacent bony structures. The use of CBCT in evaluation of osteomyelitis is restricted to detection of sequestrum formation in chronic osteomyelitis. Miscellaneous applications include assessment of (symptomatic) variants, detection and characterization of tumour and tumour-like conditions of bone. Teaching Points: Review the spectrum of MSK disorders in which CBCT may be complementary to other imaging techniques. Compare the advantages and drawbacks of CBCT compared to other imaging techniques. Define the present and future role of CBCT in musculoskeletal imaging

Analyzing the precision of JSW measurements using 3D scans and statistical models

One of the methods to diagnose rheumatoid arthritis (RA) is measuring joint space narrowing over time. A method is presented to analyze the sensitivity of this measurement to positioning of the hand. Micro-CT scans are used to generate projections of a joint under varying angles of rotation. A semi-automatic method is used to measure the joint space width (JSW) for each projection. A Statistical model is used to investigate whether the rotation can be detected from a 2D radiograph. It is shown that rotation of the hand has a significant influence on the measured JSW

Validation of Radiocarpal Joint Contact Models Based On Images from a Clinical MRI Scanner

Due to the severity and continuing escalation in occurrences of degenerative joint diseases, it is vital to establish a means of detection and prevention that could lead to an improvement in quality of life. One such means is MRI-based modeling for joint contact analysis of in vivo functional loading. The purpose of this study was to validate models generated from a clinical MR scanner for future in vivo joint contact analyses. Models were tested using 3 cadaver forearm specimens and compared with experimental data. It was found that models were validated based on contact area. Direct contact area measurements were observed to be very close to experimental data. Model force measurements were reasonable, but did not agree with experimental data as well as contact area. Peak pressure data from the models were less consistent in correspondence with experimental data. Also, radiocarpal mechanics were investigated to determine the effect of inserting a sensor into the joint space. Magnitudes of bone motions were found to be greater with film inserted than without film. Model results showed contact areas to be higher with film than without film