Thoracic dorsal root ganglia: visualisation of normal anatomy and pathological findings by T2 fast field echo (T2 FFE) compared with balanced fast field echo (B_FFE) and nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI).

AIM: To evaluate the clinical feasibility of magnetic resonance neurography (MRN) in detecting thoracic dorsal root ganglia (DRG).

MATERIALS AND

METHODS

Fifty-three healthy volunteers (23 males and 30 females; mean age, age range, 20-70 years) and eleven zoster-associated pain (ZAP) patients (6 males and 5 females; age range, 56-86 years) were enrolled for MRN scan. Balanced fast field echo (B_FFE), T2 fast field echo (T2 FFE), and signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI) sequences were compared for thoracic DRG imaging. The visualisation effect for the thoracic nerve root and overall image quality were scored on a 5-point Likert scale. The agreement was assessed by intraclass correlation coefficient (ICC) analysis. The contrast ratio, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) between DRG and perineural tissues were quantitatively evaluated in three sequences. Morphological changes of DRG on MRN images were evaluated in 11 patients.

RESULTS

All nerve visualisation scores of three sequences showed moderate to good agreement (ICC values > 0.75). T2 FFE images demonstrated the best visualisation scores of the thoracic spinal nerve among three sequences (all P < 0.001). The mean contrast ratio and SNR of DRG on T2 FFE images were higher than B_FFE and SHINKEI in both healthy volunteers and ZAP patients, respectively (most P < 0.001). B_FFE images showed highest CNR of DRG (all P < 0.001). Of the 11 patients, abnormalities of affected DRG were detected in 8 patients by T2 FFE sequence (72.7%), which was higher than B_FFE (4/11, 36.4%) and SHINKEI (5/11, 45.5%).

CONCLUSION

Compared with B_FFE and SHINKEI, the T2 FFE sequence feasibly depicts the normal morphology and abnormalities of thoracic DRG.