Opposed phase imaging in lumbar disc disease: an option providing faster image acquisition times

To investigate the utility of opposed phase imaging (OPI) (in-phase and out-of-phase) in lumbar disc disease.

A total of 127 patients suspected of disc disease were examined with both traditional lumbar spine protocol (fast spin-echo [FSE] T1-weighted, T2-weighted sagittal, and T2-weighted axial) and OPI. Images were evaluated to detect the disc disease and to assess the anatomical clarity of certain spinal structures by two different radiologists using a four-point scale (1 = inadequate, 2 = adequate, 3 = good, and 4 = optimal). Results of two methods in terms of pathologic conditions and anatomical structures were compared. Comparison of the methods and the interpretations of two radiologists were performed by using kappa statistics. The difference among two methods in terms of anatomic clarity was assessed by using Wilcoxon analysis.

Disc disease detected by each technique demonstrated concurrence (agreement was 82.4% and 93.1% for two radiologists; P < 0.05). OPI received similar scores with conventional sequences for disc disease (P > 0.05). OPI was optimal in displaying disc, marrow, osteophytes, and hemangiomas, where other structures got higher scores on conventional images (P > 0.05 and P > 0.001). But these structures had equal scores at least in one of the opposed-phase images. Acquisition time for OPI and conventional images were 4.46 and 9.01 minutes, respectively.

OPI can be a faster backup technique in evaluating the lumbar disc disease. It has a shorter image acquisition time with adequate diagnostic quality. It can be a "time saver" option for busy MR centers or may be used for patients who cannot tolerate longer acquisition times.