Research Article: Comparing the diagnostic performance of radiation dose-equivalent radiography, multi-detector computed tomography and cone beam computed tomography for finger fractures – A phantom study

Date Published: March 5, 2019

Publisher: Public Library of Science

Author(s): Carolin Sophie Reidelbach, Sebastian Moritz Goerke, Simon Carl Leschka, Claudia Neubauer, Martin Soschynski, Florian Lampert, Horst Zajonc, Elmar Kotter, Mathias Langer, Jakob Neubauer, Jan Fritz.


To compare the diagnostic performance and raters´confidence of radiography, radiography equivalent dose multi-detector computed tomography (RED-MDCT) and radiography equivalent dose cone beam computed tomography (RED-CBCT) for finger fractures.

Fractures were inflicted artificially and randomly to 10 cadaveric hands of body donors. Radiography as well as RED-MDCT and RED-CBCT imaging were performed at dose settings equivalent to radiography. Images were de-identified and analyzed by three radiologists regarding finger fractures, joint involvement and confidence with their findings. Reference standard was consensus reading by two radiologists of the fracturing protocol and high-dose multi-detector computed tomography (MDCT) images. Sensitivity and specificity were calculated and compared with Cochrane´s Q and post hoc analysis. Rater´s confidence was calculated with Friedman Test and post hoc Nemenyi Test.

Rater´s confidence, inter-rater correlation, specificity for fractures and joint involvement were higher in RED-MDCT and RED-CBCT compared to radiography. No differences between the modalities were found regarding sensitivity.

In this phantom study, radiography equivalent dose computed tomography (RED-CT) demonstrates a partly higher diagnostic accuracy than radiography. Implementing RED-CT in the diagnostic work-up of finger fractures could improve diagnostics, support correct classification and adequate treatment. Clinical studies should be performed to confirm these preliminary results.

Partial Text

When it comes to trauma of the hand, finger fractures belong to the most common fractures [1]. If a fracture is suspected, radiography is carried out first [2]. CT imaging, however, has been shown to be more accurate than radiography regarding diagnosis of certain fractures, fracture dislocation and joint involvement [3–5]. The main disadvantage of these techniques is their high radiation dose [6]. Lately, technical improvements such as iterative reconstruction or tube current modulation allowed for significant reduction of radiation dose in CT examinations, consequently enabling low-dose examinations in different regions of the body [7–11]. Several studies showed that low-dose imaging of the wrist is feasible with multi-detector computed tomography (MDCT) [12] and cone beam computed tomography (CBCT) [13,14]. CBCT was initially established in maxillofacial imaging and differs from the MDCT mainly through its detector [15]. The main difference between the detectors is that the CBCT’s flat-panel detector has no anti-scatter-grid, which makes it more prone to artifacts from scatter radiation. Also, the pixel size of the flat-panel detector is smaller, resulting on the one hand in a higher spatial resolution, but on the other hand causing more noise [16]. CBCT is an imaging modality currently on the rise in musculoskeletal radiology [14,17–19].

The Ethics Commission of the University of Freiburg approved this prospective study.

According to the reference standard, 9 out of 140 bones were fractured. In total, there were 5 fractures induced to the phalanges proximales, 2 fractures induced to the phalanges mediales and 2 fractures to the phalanges distales. One fracture had only 2 fragments, another fracture had 3 fragments, 5 fractures had 4 fragments and 2 fractures had 5 fragments. There were 6 fractures with joint involvement.

In this preclinical study on cadaveric hands, we demonstrate that the raters´ confidence in their reporting of finger fractures was higher in RED-MDCT and RED-CBCT compared to radiography. Furthermore, the specificity for fractures and joint involvement was higher in the CT imaging techniques. Sensitivity for fractures and joint involvement, however, did not differ between the modalities.




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