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Selected Publication:
Tschauner, S.
Pediatric extremity computed tomography with focus on cone beam applications and radiation protection
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Graz Medical University; 2019. pp. 86
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- Authors Med Uni Graz:
- Tschauner Sebastian
- Advisor:
- Riccabona Michael
- Singer Georg
- Sorantin Erich
- Altmetrics:
- Abstract:
- Background: Novel dedicated cone-beam computed tomography (CBCT) devices for examining the extremities have been available for a few years. They represent a possible alternative to the multidetector computed tomography (MDCT) machines commonly used for further trauma diagnostics. The corresponding scientific literature on the use of CBCT in childhood extremity trauma is scarce. The aim of this work was therefore to compare the new and the traditional method to identify the specific advantages and disadvantages in a realistic pediatric radiological setting. Material and Methods: We performed surface dose measurements on pediatric anthropomorphic hand and ankle phantoms and prospectively acquired CBCT examinations of the extremities of injured children. The phantom study was carried out utilizing thermoluminescence dosimeters, which were attached to the phantoms. Then they were irradiated several times with different exposure protocols on CBCT and MDCT. The dosimeters were subsequently read out. During the study period, 61 limb CBCTs were obtained from 59 patients prospectively, 10 of whom were additionally scanned with MDCT in parallel to allow a direct comparison. The remaining 51 MDCTs were retrospectively matched by examined region, gender, and age from the local image archive. Seven examination pairs had to be excluded, as there were discrepancies between the modalities concerning plaster casts or metal implants. A total of 54 CBCT-MDCT pairs were included. Besides, an analysis of the diagnostic value of digital radiography (DR) compared to CBCTs was performed on 47 corresponding examination pairs. Results: Measurements of surface doses on hand and ankle phantoms showed a significant dose advantage of CBCT over MDCT (3.0 milligray and 3.9 milligray, p<0.001, respectively) on average. As expected, CBCT and DR demonstrated an advantage of the sectional imaging technique, which was able to detect a higher number of fractures. Sensitivity was between 88.5% and 92.3% in CBCT and 65.4% in DR. When comparing CBCT and MDCT, the former showed a more favorable noise characteristic, both semi-objectively and subjectively (p<0.001). However, CBCT examinations were regularly affected by streak artifacts, which subjectively reduced diagnostic certainty ratings (p=0.001). Conclusions: In children, CBCT which was designed explicitly for extremity imaging semi-objectively performed better than the comparable MDCT. On the other hand, the subjective image quality and the diagnostic certainty of CBCT were rated worse, which could be attributed in particular to the presence of streak artifacts. Also, CBCT was more susceptible to motion artifacts, although they were rarely seen. Using optimized exposure protocols, the administered radiation doses of both methods (CBCT and MDCT) were in the low range of a few days of natural background radiation and therefore played a minor role in pediatric trauma setting with strict study indications.