CONTRAST-ENHANCED MR-IMAGING IN THE DIAGN OSIS OF THE FAILED BACK SURGERY SYNDROME - A PROSPECTIVE-STUDY OF 109 PATIENTS

In a prospective study, 132 previously operated disc levels in 109 pat ients with failed back surgery syndrome (FBSS) were examined by MR ima ging before and after intravenous application of a contrast agent (0.1 mmol Gd-DTPA/kg). The results were compared with current CT findings in 47 cases. The images were randomized and independently assessed by two experienced radiologists. A second intervention of a total of 30 d isc levels was performed in 28 patients. Contrast-enhanced-MR imaging (CE-MRI) improved the differentiation of scar from recurrent disc hern iation (RDH) compared to plain MRI and CT. Agreement between the two r eaders was significantly higher for CE-MRI than for the other two proc edures (p less-than-or-equal-to 0,001). CE-MRI additionally had the hi ghest diagnostic accuracy (p less-than-or-equal-to 0.001). The preoper ative diagnosis made by CE-MRI was confirmed in 27 (90 %) of the reope rated disc levels. Quantitative evaluation showed that there was no co ntrast enhancement in RDH as opposed to pronounced enhancement of 122% in scars (p less-than-or-equal-to 0.001). Evaluation with respect to scar age revealed a significant difference (p less-than-or-equal-to 0. 01) in contrast enhancement between scars less and more than 2.5 years old.