Virtual non-contrast images calculated from dual-energy CT shoulder arthrography improve the detection of intraarticular loose bodies

Christoph Stern,Dimitri N Graf,Andrea B Rosskopf,Karl Wieser,Samy Bouaicha,Reto Sutter

doi:10.1007/s00256-022-04007-7

Christoph Stern, Dimitri N Graf + Show 4 more

Open Access

https://doi.org/10.1007/s00256-022-04007-7

Copy DOI

Abstract

ObjectiveThis study aims to evaluate the image quality of virtual non-contrast (VNC) images calculated from dual-energy CT shoulder arthrography (DECT-A) and their ability to detect periosteal calcifications and intraarticular loose bodies.Materials and methodsIn 129 shoulders of 123 patients, DECT arthrography (80 kV/140 kV) was performed with diluted iodinated contrast material (80 mg/ml). VNC images were calculated with image postprocessing. VNC image quality (1 = worst, 5 = best), dose parameters, and CT numbers (intraarticular iodine, muscle, VNC joint fluid density) were assessed. Image contrast (iodine/muscle) and percentage of iodine removal were calculated. Two independent readers evaluated VNC and DECT-A images for periosteal calcifications and intraarticular loose bodies, and diagnostic confidence (1 = low, 4 = very high) was assessed.ResultsVNC images (129/129) were of good quality (median 4 (3–4)), and the mean effective dose of DECT-A scans was 2.21 mSv (± 1.0 mSv). CT numbers of iodine, muscle, and VNC joint fluid density were mean 1017.6 HU (± 251.6 HU), 64.6 HU (± 8.2 HU), and 85.3 HU (± 39.5 HU), respectively. Image contrast was mean 953.1 HU (± 251 HU) on DECT-A and 31.3 HU (± 32.3 HU) on VNC images. Iodine removal on VNC images was 91% on average. No difference was observed in the detection of periosteal calcifications between VNC (n = 25) and DECT-A images (n = 21) (p = 0.29), while the detection of intraarticular loose bodies was superior on VNC images (14 vs. 7; p = 0.02). Diagnostic confidence was higher on VNC images for both periosteal calcifications (median 3 (3–3) vs. 3 (3–3); p = 0.009) and intraarticular loose bodies (median 3 (3–4) vs. 3 (3–3); p < 0.001).ConclusionVNC images from DECT shoulder arthrography are superior to DECT-A images for the detection of intraarticular loose bodies and increase the confidence in detecting periosteal calcifications.

Highlights

Osseous fragments or intraarticular loose bodies in patients with previous shoulder dislocation or osteoarthritis can cause symptoms such as locking, snapping, pain, and reduced range of motion or instability [1,2,3]
virtual non-contrast (VNC) images from dual-energy CT shoulder arthrography (DECTA) with iodine removal allow the calculation of accurate 3D reformats of the glenoid for assessment of bone loss [7]
Further exclusions were because of metal implants (8 patients), incorrect dosage of intraarticular contrast material at arthrography (5 patients), and complete or predominantly extraarticular injection of contrast material (19 patients). This resulted in a study group of 123 patients (95 male, 28 female; mean age 36.4 years ± 14.5 years [standard deviation]) and 129 shoulders (5 male patients and 1 female patient received Dual-energy CT (DECT) after arthrography of both shoulders)

Summary

Introduction

Osseous fragments or intraarticular loose bodies in patients with previous shoulder dislocation or osteoarthritis can cause symptoms such as locking, snapping, pain, and reduced range of motion or instability [1,2,3]. In such patients, CT of the shoulder is routinely performed to localize and quantify osseous fragments or intraarticular loose bodies. VNC images from dual-energy CT shoulder arthrography (DECTA) with iodine removal allow the calculation of accurate 3D reformats of the glenoid for assessment of bone loss [7]

Methods

Results

Conclusion