The
Proof is in The Picture™
Case
Study #6
1.5T Recumbent vs. Erect MRI
Patient complains of radicular symptoms when sitting. When
imaged recumbent on a 1.5T Philips Intera (left) there is a disc
bulge at L3/4 level. Patient was then scanned in the seated position
(right) which shows an L3/4 disc protrusion/herniation with corresponding
compression on the thecal sac. Sometimes high-field MRI does not
make the diagnosis.
Recumbent (1.5T image) |
|
Seated
(.6T image) |
 |
Case
Study #7
Position Related Disc Herniation
Seated image (left) shows disc bulging at C4/5, 5/6 and 6/7. Placing
the patient in the seated, extension position shows a C4/5 disc
herniation with compression on the thecal sac and cervical cord.
Case
Study #8 (Images courtesy of Fonar)
Position Dependent Disc Herniation
Recumbent image (34A) shows degenerative disc disease at L5/S1 and
an associated disc bulge at this level. The upright image (34B)
reveals further narrowing of the disc space and a focal posterior
disc herniation (arrow) at L5/S1. Mild instability (retrolisthesis)
is present at this same level in the upright position.
Case
Study #9 (Images courtesy of Fonar)
Postoperative Spinal Instability
Recumbent image (32A) shows laminectomies at L4 and L5 and a postoperative
Grade II spondylolisthesis at L4/5. The upright flexion (32B) image
reveals further anterolisthesis of L4 on L5 (arrow). Relative to
the recumbent scan, extension (32C) reveals little reduction in
the anterolisthesis of L4 on L5, indicating that instability is
in the anterior direction.
Case
Study #10 (Images courtesy of Fonar)
Instability and Central Spinal Canal Stenosis
These scans (18A-C) show how recumbent imaging can underestimate
the maximum degree of pathology and miss its dynamic nature. The
recumbent scan (18A) shows spondylolisthesis at L4/5. The flexion
scan (18B) shows a further anterior shift of L4 on L5. The extension
scan (18C) shows a comparative posterior shift of L4 on L5. Also
note that the changes in central spinal canal stenosis are in part
a function of position, the most severe degree occurring in flexion.
|
