Loss of T2 Signal on Lumbar Spine MRI
Loss of T2 signal in the lumbar intervertebral discs represents disc degeneration, characterized by decreased water content and glycosaminoglycan (GAG) loss in the nucleus pulposus, and is a common age-related finding that does not necessarily correlate with clinical symptoms. 1, 2
What the Signal Change Represents
Decreased T2 signal intensity on MRI reflects biochemical changes in the disc matrix, specifically loss of proteoglycans and water content that normally provide the bright signal on T2-weighted images 1, 2
The nucleus pulposus normally appears bright (hyperintense) on T2-weighted images due to high water content; as degeneration progresses, this signal progressively darkens (becomes hypointense) 2, 3
Quantitative studies demonstrate that T2 signal ratio (disc signal compared to spinal cord signal) correlates negatively with age and positively with Pfirrmann degeneration grades, providing objective evidence of progressive disc degeneration 2
Associated Findings and Patterns
Modic Changes in Adjacent Vertebral Bodies
When loss of disc T2 signal is present, examine the adjacent vertebral endplates for Modic changes, which represent a spectrum of marrow alterations associated with degenerative disc disease 1:
Type 1 changes (4% prevalence): Decreased signal on T1-weighted images and increased signal on T2-weighted images, representing disrupted endplates with vascularized fibrous tissue 1
Type 2 changes (16% prevalence): Increased signal on T1-weighted images and isointense/slightly increased signal on T2-weighted images, representing fatty marrow replacement 1
Type 1 changes typically convert to Type 2 pattern over 14 months to 3 years, while Type 2 changes remain stable 1
Clinical Significance and Context
In Your Patient with Severe Hand OA
Degenerative disc changes are extremely common in the general population, occurring in the majority of individuals over age 65, with women affected more than men 4
The presence of disc degeneration on MRI does not establish causation for back pain, as these findings are frequently present in asymptomatic individuals 5
Your patient's severe hand osteoarthritis indicates a systemic predisposition to degenerative joint disease, making lumbar disc degeneration an expected finding rather than an isolated pathology 4
Distinguishing Degenerative from Inflammatory Changes
This distinction is critical when interpreting spine MRI 5:
Degenerative disc disease shows loss of T2 signal with associated findings: disc height loss, osteophytes, endplate sclerosis, and facet joint arthropathy 5
Inflammatory spondyloarthropathy shows increased T2 signal: bone marrow edema at vertebral corners, inflammatory changes at discovertebral junctions, and absence of osteophytes 5
The presence of osteophytes and disc space narrowing strongly favors degenerative rather than inflammatory etiology 5
Diagnostic Accuracy Considerations
MRI has 92% positive predictive value for identifying morphologically abnormal discs when compared to discography, making it the neuroimaging study of choice for evaluating disc pathology 5
T1rho and T2 mapping techniques can detect early disc degeneration before conventional T2-weighted images show obvious changes, though these advanced sequences are primarily research tools 6
Standard T2-weighted imaging remains the clinical standard, with targeted measurement of the brightest, most homogenous area of the nucleus pulposus providing the best differentiation between degeneration grades 3
Common Pitfalls to Avoid
Do not assume that disc degeneration visible on MRI is the source of a patient's pain, as the correlation between imaging findings and symptoms is poor, particularly in older adults 5
Do not overlook the need to assess for cord signal changes (increased T2 signal within the spinal cord itself), which would indicate myelopathy and represent a more urgent clinical concern requiring different management 5, 7
In patients with systemic inflammatory conditions or inflammatory back pain, do not mistake early inflammatory changes for degenerative disease—look specifically for bone marrow edema patterns and absence of osteophytes 5