Hyperintense vertebral lesions

IntroductionDisk disease and especially disk herniation is commonlythe best recognized form of degenerative disease of thespine. However, it has always to be remembered that spinedegeneration is a multilevel and multistructural disorder ofboth soft tissue and bony elements of the spine. At theparticular level it affects several anatomical structures ofdiskovertebral unit: intervertebral disk, vertebral bodies,facet joints, ligamenta flava, longitudinal ligaments [1–3].Involvement of the vertebrae is a typical feature of thedegenerative disease of the spine and is present already inthe earliest stages of the pathological process. Spinedegeneration begins simultaneously in the intervertebraldisk and the adjacent vertebral endplate cartilage whichresults in the inflammatory reaction in the parts of thevertebral bodies located in the direct vicinity of theendplates and thus increased water content in these areas.This early stage is defined as the so called asepticspondylodiscitis or discovertebritis and is equivalent toModic type 1 vertebral body degeneration lesions. It has tobe differentiated from infectious spondylodiscitis (seebelow). In the later stages vertebral changes also followdegenerative lesions of the other spine structures andpresent as the other types of vertebral degeneration, likefatty degeneration (Modic type 2 lesions), sclerotic degen-eration (Modic type 3 lesions), erosive osteochondrosis ofthe vertebral endplates and facet joint degeneration [1–6].Degenerative hyperintense lesions of the vertebraeMR is an imaging method of choice in diagnostics of thespine degeneration, including vertebral degeneration. Themost common types of the vertebral degeneration, i.e.Modic type 1 and type 2 lesions, could be visualized onlywith MR. Modic type 1 lesions are hyperintense on T2-weighted and fat saturation images, while Modic type 2lesions are typically hyperintense on T1-weighted and tothe lesser extent on T2-weighted images. These hyperin-tense areas are located always adjacent to the vertebralendplates, however they can involve variable part of thevertebral bodies, from the narrow band to the entirevertebral body [7–10].Hyperintensities could be also seen in the other typesof vertebral degeneration. Osteophytes of the vertebralbodies are often hyperintense on T1 and/or T2-weighedimages. Degeneration of the facet joints may exhibithyperintensive areas in the articular processes. Erosiveosteochondrosis, apart from the irregularities of thevertebral endplates is usually accompanied by degenera-tive hyperintense lesions in the adjacent parts of thevertebral bodies. Degenerative spondylolisthesis is typi-cally associated with hyperintense changes of the vertebralbodies and articular processes of the facet joints at theaffected level. Spinal stenosis always involves vertebralstructure and thus results again in hyperintense Modictype 1 and/or type 2 lesions of the vertebral bodies andarticular processes [3, 5].Full evaluation of the hyperintense vertebral lesionsrequires their assessment with multiple MR sequencesand sometimes with the other modalities. MR protocolmust always include T1-weighted, T2-weighted and T2-fat saturation (FatSat) images; sometimes it should besupplemented by post-contrast T1-weighted images.Modic type 1 lesions are hyperintense on T2-weightedand FatSat images, while hypointense on T1-weightedimages (Fig. 1). Modic type 2 lesions have increased