PURPOSE: This study was done to test a series of MR sequences for evaluating the sciatic nerve after total hip arthroplasty (THA). MATERIAL AND METHODS: The study protocol was approved by the institutional review board. Informed consent was obtained from all patients. Twenty-five patients (11 men and 14 women mean age: 62.3±5.7 years) with THA were included in this prospective study. MRI protocol included sequences that were preliminarily tailored for nerve imaging in patients with THA: proton density (PD)-weighted turbo SE, T1-weighted turbo SE (TSE) 3 mm thickness, T1-weighted turbo SE (TSE) 6 mm thickness, T1-weighted turbo SE with high bandwidth (TSE hBW), T2- weighted TSE, T2-weighted with fat saturation and short-tau inversion recovery (STIR). For each sequence, we evaluated the visibility of the sciatic nerve using a semiquantitative score (0=total masking; 1=insufficient visibility; 2=sufficient visibility; 3=optimal visibility). The sum of the scores given to each sequence was divided by the maximal sum, obtaining a percentage visibility index. Friedman and sign tests were used for statistical analysis. RESULTS: MR examination time was approximately 40 min. No patients reported pain, heat or symptoms related to nerve stimulation. The visibility index ranged between 88% and 70% for the first four sequences. The T1-weighted TSE hBW sequence had the best visibility index (P<.05). The visibility indexes of the first four sequences were significantly higher (P<.004, sign test) than those of the remaining three sequences. CONCLUSION: The sciatic nerve could be studied at 1.5 T in patients following THA. The nerve is better visualized with T1-weighted TSE hBW sequences. On T2-weighted sequences and STIR, the visibility of the nerve is low.
PURPOSE: This study was done to test a series of MR sequences for evaluating the sciatic nerve after total hip arthroplasty (THA). MATERIAL AND METHODS: The study protocol was approved by the institutional review board. Informed consent was obtained from all patients. Twenty-five patients (11 men and 14 women mean age: 62.3±5.7 years) with THA were included in this prospective study. MRI protocol included sequences that were preliminarily tailored for nerve imaging in patients with THA: proton density (PD)-weighted turbo SE, T1-weighted turbo SE (TSE) 3 mm thickness, T1-weighted turbo SE (TSE) 6 mm thickness, T1-weighted turbo SE with high bandwidth (TSE hBW), T2- weighted TSE, T2-weighted with fat saturation and short-tau inversion recovery (STIR). For each sequence, we evaluated the visibility of the sciatic nerve using a semiquantitative score (0=total masking; 1=insufficient visibility; 2=sufficient visibility; 3=optimal visibility). The sum of the scores given to each sequence was divided by the maximal sum, obtaining a percentage visibility index. Friedman and sign tests were used for statistical analysis. RESULTS: MR examination time was approximately 40 min. No patients reported pain, heat or symptoms related to nerve stimulation. The visibility index ranged between 88% and 70% for the first four sequences. The T1-weighted TSE hBW sequence had the best visibility index (P<.05). The visibility indexes of the first four sequences were significantly higher (P<.004, sign test) than those of the remaining three sequences. CONCLUSION: The sciatic nerve could be studied at 1.5 T in patients following THA. The nerve is better visualized with T1-weighted TSE hBW sequences. On T2-weighted sequences and STIR, the visibility of the nerve is low.