Diffusion-Weighted MRI "Claw Sign" Improves Differentiation of Infectious from Degenerative Modic Type 1 Signal Changes of the Spine

Patel, Kalpesh; Poplawski, Michael; Pawha, Puneet; Naidich, Thomas P.; Tanenbaum, Lawrence N.

doi:10.3174/ajnr.a3948

Cited by 93 publications

(59 citation statements)

References 14 publications

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“…MC likely has several etiologies, with P. acnes infection of the disc being one of them. The shape of MC on sagittal MRI distinguishes infectious from non‐infectious etiology, where the absence of a claw‐shape (bigger anterior lesion size) is specific for disc infection. This is in agreement with the mid‐coronal reaction pattern in MRI and histology, that is, fibrosis, TNF‐α and CD3 reactivity, seen in this current study.…”

Section: Discussionmentioning

confidence: 99%

Propionibacterium acnes infected intervertebral discs cause vertebral bone marrow lesions consistent with Modic changes

Dudli

Liebenberg

Magnitsky

et al. 2016

Journal Orthopaedic Research

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Modic type I change (MC1) are vertebral bone marrow lesions adjacent to degenerated discs that are specific for discogenic low back pain. The etiopathogenesis is unknown, but occult discitis, in particular with Propionibacteria acnes (P. acnes), has been suggested as a possible etiology. If true, antibiotic therapy should be considered for patients with MC1. However, this hypothesis is controversial. While some studies report up to 40% infection rate in herniated discs, others fail to detect infected discs and attribute reports of positive cultures to contamination during sampling procedure. Irrespective of the clinical controversy, whether it is biologically plausible for P. acnes to cause MC1 has never been investigated. Therefore, the objective of this study was to test if P. acnes can proliferate within discs and cause reactive changes in the adjacent bone marrow. P. acnes was aseptically isolated from a symptomatic human L4/5 disc with MC1 and injected into rat tail discs. We demonstrate proliferation of P. acnes and up-regulation of IL-1 and IL-6 within three days of inoculation. At day-7, disc degeneration was apparent along with fibrotic endplate erosion. TNF-a immunoreactivity was enhanced within the effected endplates along with cellular infiltrates. The bone marrow appeared normal. At day-14, endplates and trabecular bone close to the disc were almost completely resorbed and fibrotic tissue extended into the bone marrow. T-cells and TNF-a immunoreactivity were identified at the disc/marrow junction. On MRI, bone marrow showed MC1-like changes. In conclusion, P. acnes proliferate within the disc, induce degeneration, and cause MC1-like changes in the adjacent bone marrow. ß

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Section: Discussionmentioning

confidence: 99%

Propionibacterium acnes infected intervertebral discs cause vertebral bone marrow lesions consistent with Modic changes

Dudli

Liebenberg

Magnitsky

et al. 2016

Journal Orthopaedic Research

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“…DOM, the other hand, shows diffusely increased diffusion signal throughout the involved vertebral bodies (Figure 21). 104 Absence of diffusion hyperintensity in the intervertebral disk space in degenerative disease is also a helpful discriminator from infectious processes. 103 The imaging features of inflammatory arthropathy can overlap those of DOM.…”

Section: Spine Infectionmentioning

confidence: 99%

Imaging of Degenerative and Infectious Conditions of the Spine

Shah

Ross

2016

Neurosurgery

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Imaging is important in the evaluation of patients with degenerative disease and infectious processes. There are numerous conditions that can manifest as low back pain (LBP) or neck pain in a patient, and in many cases, the cause may be multifactorial. Clinical history and physical examination are key components in the evaluation of such patients; however, physical examination has variable sensitivity and specificity. Although studies have demonstrated that uncomplicated acute LBP and/or radiculopathy are self-limited conditions that do not warrant any imaging, neuroimaging can provide clear anatomic delineation of potential causes of the patient's clinical presentation. Various professional organizations have recommendations for imaging of LBP, which generally agree that an imaging study is not indicated for patients with uncomplicated LBP or radiculopathy without a red flag (eg, neurological deficit such as major weakness or numbness in lower extremities, bowel or bladder dysfunction, saddle anesthesia, fever, history of cancer, intravenous drug use, immunosuppression, trauma, or worsening symptoms). Different imaging modalities have a complementary role in the diagnosis of pathologies affecting the spine. In this review, we discuss the standard nomenclature for lumbar disk pathology and the utility of various clinical imaging techniques in the evaluation of LBP/neck pain for potential neurosurgical management. The imaging appearance of spinal infections and potential mimics also is reviewed. Finally, we discuss advanced neuroradiological techniques that offer greater microstructural and functional information. ABBREVIATIONS: ADC, apparent diffusion coefficient; DTI, diffusion tensor imaging; DWI, diffusionweighted imaging; DOM, diskitis-osteomyelitis; LBP, low back pain; MRM, magnetic resonance myelography; SNA, spinal neuroarthropathy; SPECT, single-positron emission computed tomography; STIR, short tau inversion recovery Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.neurosurgery-online.com). the diagnosis of patients with degenerative and infectious processes affecting the spine, with specific attention to the lumbar spine. NEURORADIOLOGY REVIEW SERIES NEURORADIOLOGY REVIEW SERIES DEGENERATIVE SPINELBP is ubiquitous, affecting up to two-thirds of adults at some period in their lives.3 Imaging, primarily with MRI and CT, is used to evaluate the source of both LBP and neck pain. These imaging modalities commonly identify disk degeneration, disk herniations, and posterior element arthopathy; however, the imaging findings of spine degeneration are present in a high proportion of asymptomatic individuals and increase with age. 5,6 Although many imaged-based degenerative changes are due to the normal aging process, such imaging findings are often interpreted as the cause of the patient's back pain and initiate a cascade of medical and surgical interventions, wh...

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“…Thus, the T1-w signal ratios, assessed in this study, should be interpreted with caution, and may not be directly applied to any other MR field strength or technical settings. Finally, since they were not part of routine MR imaging, advanced techniques were not included, such as previously investigated diffusion-weighted imaging, demonstrating a particular appearance, termed the claw sign, to identify MT1 [49]. Our study, however, included unenhanced standard images only, because contrast-enhanced images were not available in all MT1 patients.…”

Section: Discussionmentioning

confidence: 99%

Vertebral Bone Marrow and Endplate Assessment on MR Imaging for the Differentiation of Modic Type 1 Endplate Changes and Infectious Spondylodiscitis

Schwarz‐Nemec

Friedrich

Stihsen

et al. 2020

JCM

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On magnetic resonance (MR) imaging, Modic type 1 (MT1) endplate changes and infectious spondylodiscitis share similar findings. Therefore, this study investigated vertebral bone marrow and endplate changes to enable their differentiation. The lumbar spine MR examinations of 91 adult patients were retrospectively included: 39 with MT1; 19 with early spondylodiscitis without abscess; and 33 with advanced spondylodiscitis with abscess. The assessment included percentage of bone marrow edema on sagittal short tau inversion recovery images, and the signal ratio of edema to unaffected bone and endplate contour (normal; irregular, yet intact; blurred; destructive) on sagittal unenhanced T1-weighted images. Differences were tested for statistical significance by Chi-square test and mixed model analysis of variance. The MR diagnostic accuracy in differentiating MT1 and spondylodiscitis was assessed by cross-tabulation and receiver-operating characteristic analysis. The endplate contours, edema extents, and T1-signal ratios of MT1 (extent, 31.96%; ratio, 0.83) were significantly different (p < 0.001) from early spondylodiscitis (56.42%; 0.60), and advanced spondylodiscitis (91.84%; 0.61). The highest diagnostic accuracy (sensitivity, 94.87%; specificity, 94.23%; accuracy, 94.51%) in identifying MT1 was provided by an irregular, yet intact endplate contour. This may be a useful MR feature for the differentiation between MT1 and spondylodiscitis, particularly in its early stage.

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Diffusion-Weighted MRI "Claw Sign" Improves Differentiation of Infectious from Degenerative Modic Type 1 Signal Changes of the Spine

Cited by 93 publications

References 14 publications

Propionibacterium acnes infected intervertebral discs cause vertebral bone marrow lesions consistent with Modic changes

Propionibacterium acnes infected intervertebral discs cause vertebral bone marrow lesions consistent with Modic changes

Imaging of Degenerative and Infectious Conditions of the Spine

Vertebral Bone Marrow and Endplate Assessment on MR Imaging for the Differentiation of Modic Type 1 Endplate Changes and Infectious Spondylodiscitis

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