Evaluation of artifacts produced by cannulated and solid-core screws using magnetic resonance imaging and computed tomography

Abstract

This study aimed to evaluate, using both magnetic resonance imaging (MRI) and computed tomography (CT), the imaging artifacts associated with two types of titanium screws—cannulated and solid—from three different manufacturers, implanted in the canine humeral condyle. Three groups were established: G1 – 3.5 × 30 mm solid cortical screws and partially threaded cannulated screws; G2 – 3.5 × 28 mm solid cortical screws and 3.5 × 26 mm fully threaded conical compression cannulated screws; and G3 – 3.5 × 30 mm solid screws and 3.0 × 26 mm fully threaded conical compression cannulated screws. MRI evaluation was performed using SE DP/T2, Turbo 3D T1, STIR, and fast FLAIR sequences, while CT evaluation used transverse images. On MRI, solid screws produced more discrete and localized artifacts, mainly as peri-implant signal void/blooming with minimal geometric distortion and mild limitation of cortical and articular surface assessment. In contrast, cannulated screws generated larger areas of signal loss, especially in Turbo 3D T1 and fat-suppressed STIR/FLAIR sequences, although humeral condyle evaluation remained feasible. On CT, solid screws exhibited more pronounced metallic artifacts (beam hardening, streaks, mild blooming) compared with cannulated screws; however, these artifacts did not prevent assessment of peri-implant structures. Artifact measurements on MRI (Turbo 3D T1) and CT were higher for cannulated screws in G1 and G2, whereas in G3 solid screw produced greater artifact. In conclusion, both design and material composition of the screw significantly influence image quality, highlighting the importance of considering these factors when selecting the screw and planning imaging protocols.