Keywords:
Extremities, Musculoskeletal bone, Trauma, Cone beam CT, Digital radiography, Diagnostic procedure, Patterns of Care
Authors:
B. Gibney, J. Ryan, M. Smith, A. Moughty, E. C. Kavanagh, D. Hynes, P. J. MacMahon; Dublin/IE
DOI:
10.26044/ecr2019/C-0447
Aims and objectives
Fractures of the wrist and hand are the reason for 1.5% of all emergency department visits(1). Less than 20% of patients with a clinically suspected scaphoid fracture have a true fracture (2).
In the acute setting 5-20% of scaphoid fractures can be missed on initial radiographs(3).
Plain radiography may be limited by superposition of anatomical structures,
suboptimal positioning and technique,
and suboptimal patient cooperation in emergency settings (4).
Failure to immobilise a wrist with a fracture can lead to complications such as non-union,
avascular necrosis,
development of carpal instability and osteoarthritis (5,
6).
Conversely,
in the majority of cases where no fracture has occurred,
unnecessary immobilisation can lead to overtreatment,
increased healthcare costs and loss of productivity for the patient(7).
It is common practice to immobilise the wrist until the probability of a true fracture being present,
through imaging or clinical follow up,
is deemed acceptably low.
However recent cost effectiveness studies comparing empiric immobilisation to immediate MRI or MDCT in the setting of negative radiographs,
found immediate advanced imaging to be a better choice for reducing costs and morbidity(8,
9).
CBCT creates high resolution scans using a single 210 degree rotation of conical beam which falls on a flat-panel detector rather than a helically rotating fan shaped beam on a linear multi-detector used in conventional CT.
The advantages of this technology include higher spatial resolution,
reduction of metal artefacts,
portability and low radiation dose(10,
11,
12).
The dose of CBCT of the wrist has been measured in a direct comparison as 3.6 times less than the dose from MDCT and 2.4 times more than the dose from AP and lateral projection wrist radiographs(13).
CBCT has been shown in several studies to be more accurate than conventional radiography for the diagnosis of fractures of small bones as well as being faster to perform and yielding more diagnostic information(12,
14,
15).
We aimed to evaluate the diagnostic value of CBCT for radiocarpal fractures that are not visible on standar radiographs.