3D cone-beam CT with a twin robotic x-ray system in elbow imaging: comparison of image quality to high-resolution multidetector CT

Jan-Peter Grunz,Süleyman Ergün,Lenhard Pennig,Andreas Steven Kunz,Carsten Herbert Gietzen,Andreas Max Weng,Rainer Schmitt,Stefan Herz,Maike Veyhl-Wichmann,Thorsten Alexander Bley,Tobias Gassenmaier

doi:10.1186/s41747-020-00177-y

Abstract

BackgroundElbow imaging is challenging with conventional multidetector computed tomography (MDCT), while cone-beam CT (CBCT) provides superior options. We compared intra-individually CBCT versus MDCT image quality in cadaveric elbows.MethodsA twin robotic x-ray system with new CBCT mode and a high-resolution clinical MDCT were compared in 16 cadaveric elbows. Both systems were operated with a dedicated low-dose (LD) protocol (equivalent volume CT dose index [CTDIvol(16 cm)] = 3.3 mGy) and a regular clinical scan dose (RD) protocol (CTDIvol(16 cm) = 13.8 mGy). Image quality was evaluated by two radiologists (R1 and R2) on a seven-point Likert scale, and estimation of signal intensity in cancellous bone was conducted. Wilcoxon signed-rank tests and intraclass correlation coefficient (ICC) statistics were used.ResultsThe CBCT prototype provided superior subjective image quality compared to MDCT scans (for RD, p ≤ 0.004; for LD, p ≤ 0.001). Image quality was rated very good or excellent in 100% of the cases by both readers for RD CBCT, 100% (R1) and 93.8% (R2) for LD CBCT, 62.6% and 43.8% for RD MDCT, and 0.0% and 0.0% for LD MDCT. Single-measure ICC was 0.95 (95% confidence interval 0.91–0.97; p < 0.001). Software-based assessment supported subjective findings with less “undecided” pixels in CBCT than dose-equivalent MDCT (p < 0.001). No significant difference was found between LD CBCT and RD MDCT.ConclusionsIn cadaveric elbow studies, the tested cone-beam CT prototype delivered superior image quality compared to high-end multidetector CT and showed a potential for considerable dose reduction.

Highlights

Elbow imaging is challenging with conventional multidetector computed tomography (MDCT), while cone-beam CT (CBCT) provides superior options
Cadaveric specimens We examined the elbow joints of eight, randomly chosen, formalin-fixed cadaveric specimens with the novel prototype cone-beam CT scan mode of a multiuse, twin robotic x-ray system (Multitom Rax, Siemens Healthineers, Erlangen, Germany) and a high-resolution multidetector CT scanner (Somatom Force, Siemens Healthineers, Erlangen, Germany)
Subjective image quality Of 64 elbow studies, both readers considered all 16 regular clinical scan dose (RD) CBCT, 16 LD CBCT, and 16 RD MDCT scans to be suitable for clinical evaluation

Summary

Introduction

Elbow imaging is challenging with conventional multidetector computed tomography (MDCT), while cone-beam CT (CBCT) provides superior options. We compared intra-individually CBCT versus MDCT image quality in cadaveric elbows. Cone-beam computed tomography (CBCT) has been an integral part of dental imaging for many years [1, 2]. With the excellent depiction of the osseous tissue and the establishment of dedicated extremity scanners, CBCT provides several advantages over conventional multidetector CT (MDCT), for trauma imaging [4]. While the upsides of the cone-beam technology have been examined for wrist and finger imaging before [8,9,10], the application to the elbow region has not been well established in the literature so far. The diagnostic routine usually comprises plain radiography for fracture diagnosis, severely displaced fracture patterns or suspected occult coronoid or radial head fractures may require additional MDCT imaging for further evaluation and surgical planning [12]

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Results

Conclusion