Evaluation of a modular flexible coil for thoracic outlet syndrome MRI at 3 T

Thoracic outlet syndrome (TOS) results from compression of neurovascular structures. Dynamic MRI may enhance diagnostic accuracy; however, conventional rigid coils are suboptimal for imaging during functional maneuvers. This study compared a custom-built flexible modular coil (ModFlex) with a conventional torso coil, focusing on the interscalene (ISS) and costoclavicular spaces (CCS). Nine healthy volunteers participated in 3 T TOS MRI using both coils. The signal-to-noise ratio (SNR) was calculated in two regions of interest (ISS and CCS). Additionally, g-factors were evaluated for simulated GRAPPA parallel imaging factors from 3 to 6. Two clinicians visually rated T1-weighted sagittal images to assess ModFlex coil performance. Quantitative data were compared using the Wilcoxon signed-rank and the ranks with the sign test. The ModFlex demonstrated a significantly higher SNR in the CCS (+ 39%, p = 0.004), a trend toward higher SNR in the ISS (+ 17%, p = 0.098), and significantly lower g-factors (i.e., higher parallel imaging performance) across all acceleration levels (p < 0.008). The clinicians' evaluation was generally consistent with quantitative findings, although not conclusive. GRAPPA acceleration provided better image quality than SMS (p = 0.008). Overall, modular flexible coils support faster, higher-quality dynamic TOS MRI protocols, potentially improving diagnostic reliability, and patient comfort.