MRI findings of disc protrusion , nerve root displacement or compression , disc degeneration , and high intensity zone are all associated with LBP , but individually , none of these abnormalities provides a strong indication that LBP is attributable to underlying pathology .
This limits their value in refining epidemiological case definitions for LBP
OBJECTIVE to assess how confidently  low back pain ( LBP ) can be attributed to abnormalities on magnetic resonance imaging ( MRI ) , and thereby explore the potential value of MRI abnormalities in refining case definition for mechanical LBP in epidemiological research .
SUMMARY OF BACKGROUND DATA most epidemiological studies of mechanical LBP have defined cases only by reported symptoms , but it is possible that the potency of causes differs depending on whether there is demonstrable underlying spinal pathology .
Interobserver and Intraobserver Variability in Interpretation of Lumbar Disc Abnormalities: A Comparison of Two Nomenclatures
Study Design A double-blind prospect i ve study was used to measure interobserver and intraobserver variability when interpreting lumbar spine magnetic resonance imaging studies of disc abnormalities . Objectives To evaluate reader consistercy when interpreting disc extension beyond the interspace , and assess the effect of two distinct nomenclatures on reader consistency . Summary of Background Data Interobserver and intraobserver variability in interpretation of lumbar disc abnormalities is an important consideration in analyzing the technical efficacy of an imaging modality . However , this has not been well measured ( particularly for st and ardized nomenclature ) . Methods  Magnetic resonance imaging studies of the lumbar spine performed prospect ively in 98 asymptomatic volunteers , and an additional 27 selected studies from symptomatic patients , were read blindly by two experienced neuroradiologists , using two separate nomenclatures . Only the discs were evaluated ( 625 interspaces ) . Nomenclature I was normal , bulge , herniation . Nomenclature II was normal , bulge , protrusion , extrusion . Intraobserver and interobserver variation were measured with Kappa statistic analysis . Results Interobserver agreement was 80 % for both nomenclatures with a Kappa statistic of 0.58 . Intraobserver agreement was 86 % for each reader , with a Kappa statistic of 0.71 and 0.69 , respectively . The most common disagreement was for normal versus bulge . The next most common disagreement ( 5–6 % ) was for bulge versus herniation ( or protrusion in Nomenclature II ) . Herniation was read in 23 % of the asymptomatic subjects . Using Nomenclature II . protrusion was seen in 27 % of these subjects . Extrusion was read in only two asymptomatic subjects . Conclusions Experienced readers using st and ardized nomenclature showed moderate to substantia agreement when interpreting disc extension beyond the interspace on magnetic resonance imaging
MRI findings of disc protrusion , nerve root displacement or compression , disc degeneration , and high intensity zone are all associated with LBP , but individually , none of these abnormalities provides a strong indication that LBP is attributable to underlying pathology .
This limits their value in refining epidemiological case definitions for LBP
OBJECTIVE to assess how confidently  low back pain ( LBP ) can be attributed to abnormalities on magnetic resonance imaging ( MRI ) , and thereby explore the potential value of MRI abnormalities in refining case definition for mechanical LBP in epidemiological research .
SUMMARY OF BACKGROUND DATA most epidemiological studies of mechanical LBP have defined cases only by reported symptoms , but it is possible that the potency of causes differs depending on whether there is demonstrable underlying spinal pathology .