Magnetic resonance imaging of the lumbar spine after epidural and nerve root injection therapy: evaluation of soft tissue changes

OBJECTIVE: Magnetic resonance imaging (MRI) was performed to evaluate soft tissue changes after nerve root and epidural injections in lumbar spine in patients with radiculopathy. MATERIALS/METHODS: Patients underwent a multiple-shot injection protocol to nerve root/epidural space. The MRI protocol included T1-weighted, T2-weighted, STIR, and contrast-enhanced, fat-saturated T1-weighted sequences before and after treatment. RESULTS: In all treated patients, a diffuse wedge-shaped edema in paravertebral tissues with a slight contrast enhancement was seen. Two small hematomas in the paravertebral muscle were noted. No changes in the epidural space, the abscess, or a lipodystrophy in epidural/nerve root space occurred. CONCLUSION: Normal tissue changes after injection therapy of lumbar radiculopathy include wedge-shaped tissue edema at the injection level. In a minority of patients, small hematomas may occur.