Peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images: correlation with macroscopic and microscopic findings in elderly cadavers.
OBJECTIVE
To correlate the peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images with the macroscopic and microscopic findings in cadavers derived from elderly subjects.


METHODS
Twenty-eight intervertebral disks (16 lumbar and 12 cervical) derived from four nonembalmed cadavers were examined with T1-weighted spin echo and proton density-weighted and T2-weighted fast spin echo MR imaging. The signal intensities of the annulus fibrosus were evaluated on sagittal MR images and correlated with the findings on corresponding sagittal anatomic sections. The MR imaging-histologic correlation was then studied.


RESULTS
Peripheral focal low signal intensity areas and adjacent regions of high signal intensity were found in five lumbar intervertebral disks. Peripheral focal low signal intensity regions consisted of disorganized compact annular fibers, tiny fissures, and dense fibrosis. The high signal intensity regions, adjacent to the areas of low signal intensity, consisted of mucoid degeneration, tiny fissures, and chondroid metaplasia.


CONCLUSIONS
Awareness of the histologic findings in regions that reveal peripheral focal low signal intensity with adjacent regions of high signal intensity in the degenerated annulus fibrosus on T2-weighted images may facilitate effective interpretation of clinical MR images of the spine.
Ahn
J M
JM
Department of Radiology, Veterans Affairs Medical Center, San Diego, CA 92161, USA.
Muhle
C
C
Kang
H S
HS
Haghighi
P
P
Trudell
D
D
Resnick
D
D
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D013122:Spinal Diseases / Q000473:pathology