ABSTRACT
Objective To investigate the value of three dimensional time-of-flight (3D-TO)F) and three dimensional fast imaging employing steady state acquisition (3D-FIESTA)sequences in evaluation on spatial relationship among trigeminal nerve,facial nerve and peripheral vessels before microvascular decompression(MVD)with 3.0 T MR.Methods Data of MRI of 36 patients with trigeminal neuralgia (TN) and 31 with hemifacial spasm (HFS) before MVD were analyzed retrospectively.The intra-observer agreement for the spatial relationship among trigeminal nerve,facial nerve and adjacent blood vessels were observed.The differences of occurrence rates of neurovascular compression (NVC) of symptomatic side and asymptomatic side in TN and HFS patients were compared.Taking surgical results as the gold standards,the diagnostic efficacy for neurovascular relationships of symptomatic side with 3D-TOF and 3D-FIESTA sequences were calculated.Results The consistency between two observers in assessing relationship of trigeminal nerve,facial nerve and adjacent blood vessels of symptomatic and asymptomatic was good (all Kappa≥0.75,all P＜0.001).In both of TN and HFS patients,the occurrence rates of NVC of symptomatic side were significantly higher than those of asymptomatic side (x2=26.13,20.81,both P＜ 0.001).The accuracy,sensitivity,specificity,positive predictive value and negative predictive value of 3D-TOF and 3D-FIESTA sequences in displaying relationship of trigeminal nerve and vascular was 97.22％ (35/36),97.06％ (33/34),100％ (2/2),100％ (33/33)and 66.67％ (2/3),respectively,of relationship between facial nerve and vascular was 93.55％ (29/31),96.55％ (28/29),50.00％ (1/2),96.55％ (28/29) and 50.00％ (1/2),respectively.Conclusion 3D-TOF and 3D-FIESTA sequences can clearly display the spatial relationship of nerve and adjacent vessels,therefore providing imaging evidences for MVD.