To investigate the diagnostic value of water excitation (PROSET) sequence in the compressed responsible nerve roots of lumbar disc herniation (LDH).

A total of 80 patients of LDH with symptoms and signs of single nerve root compression treated in Hongqi Hospital Affiliated to Mudanjiang Medical College from September 2020 to May 2021 were analyzed retrospectively. Magnetic resonance imaging (MRI) conventional scanning and PROSET sequence were used to diagnose responsible compressed nerve roots respectively. The consistency between the results of MRI routine scanning and PROSET sequence in the diagnosis of responsible compressed nerve root and clinical diagnosis was analyzed. Taking the clinical diagnosis results as the 'gold standard', the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of MRI routine scanning and PROSET sequence were calculated respectively.

Among the 80 patients, 44 patients showed L5 nerve root compression and 36 patients showed S1 nerve root compression. Conventional MRI scan showed that L5 nerve root was compressed in 43 patients and S1 nerve root was compressed in 38 patients. PROSET sequence showed L5 nerve root compression in 45 patients and S1 nerve root compression in 36 patients. Kappa test showed that the consistency between the diagnosis of L5 and S1 nerve root compression by routine MRI and the clinical diagnosis was medium (Kappa=0.572, 0.698), while the consistency between the diagnosis of L5 and S1 nerve root compression by PROSET sequence and the clinical diagnosis was good (Kappa=0.873, 0.899). The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of MRI in the diagnosis of L5 nerve root compression were 79.5%, 77.8%, 78.8%, 81.4% and 75.7% respectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PROSET sequence in the diagnosis of L5 nerve root compression were 95.5%, 91.7%, 93.8%, 93.3% and 94.3% respectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PROSET sequence in the diagnosis of S1 and L5 nerve root compression were higher than those of MRI. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of MRI routine scanning and PROSET sequence in the diagnosis of S1 nerve root compression were higher than those in the diagnosis of L5 nerve root compression.

PROSET sequence has advantages in the localization of responsible compressed nerve roots in LDH, and can assist in routine MRI scanning.