Real-Time Ultrasound/MRI Fusion for Suprasacral Parallel Shift Approach to Lumbosacral Plexus Blockade and Analysis of Injectate Spread: An Exploratory Randomized Controlled Trial

Figure 1

The ultrasonographic (a) and MR (b) images are fused and displayed side-by-side. The blue line in the top is the projection of the block needle and the large green circle marks the anticipated intersection of the block needle tip and the ultrasound beam, here coinciding with the rami of spinal nerve L5 (yellow arrow) displayed on the MR image. The line of small blue and yellow dots marks the anticipated trajectory of the block needle prior to and after the intersection with the ultrasound beam, respectively. PMM, major psoas muscle; S, sacral ala; TP L4-5, transverse processes of the fourth and fifth lumbar vertebral bodies.

(a)

(b)