Diagnostics of Spondylodiscitis and its most frequent complications

Transcription

1 Diagnostics of Spondylodiscitis and its most frequent complications Poster No.: C-1536 Congress: ECR 2017 Type: Educational Exhibit Authors: M. Veselova, V. Mazaev, M. Molodtsov; Moscow/RU Keywords: Musculoskeletal spine, Neuroradiology spine, CT, MR, Contrast agent-intravenous, Inflammation, Abscess DOI: /ecr2017/C-1536 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 21

2 Learning objectives Learning the main imaging findings of spondylodiscitis, its most frequent complications and outcomes on Computed Tomography and Magnetic Resonance Imaging. Page 2 of 21

3 Background Spondylodiscitis - an inflammatory disease of the spine that affects the intervertebral disc and the adjacent vertebral body. It is clinically manifested by fever and back pain. Discitis exhibits a bimodal age distribution, with peaks in early childhood and after age of 50. Male predominance can be observed. Risk factors for discitis include diabetes, old age, immunosuppression, drug use, alcoholism, and renal failure. Etiology The most common causes of spondylodiscitis: Hematogenous penetration of infection to intervertebral disc from other sources of infection (urogenital system, respiratory system) Development of spondylodiscitis as complications after injuries and surgeries on the spine. (Fig.1, Fig.2). Infectious agents can be classified as follows: Bacterial (the most frequent pathogens - staphilococcus aureus (about 50% of cases) -pseudomonas aeruginosa (drug addicts), streptococcus (often patients with bacterial endocarditis), H.fluenzae) Tuberculosis Parasitic (Echinococcus, Toxoplasma) Fungal Pathogenesis In adults infection is thought to begin at the vertebral body endplate, extending into the intervertebral disc space and then into the adjacent vertebral body endplate. In the paediatric age group infection often starts in the intervertebral disc itself As the disease progresses, the infection may spread to the area of the spinal canal and paravertebral soft tissue and can cause such complications as: Epidural abscess Paravertebral abscess Spread of infection to articular, transverse and spinous processes, causing their destruction Disease outcome Progression of the spondylodiscitis leads to the destruction of the vertebral body and deformation of the spine (most frequently kyphosis ) and gross neurological disorders. Page 3 of 21

4 In untreated cases, bony sclerosis may begin to appear in weeks. Bone block occurs between the vertebral bodies as an outcome of the disease. Under the effect of anti-inflammatory therapy detectable changes are often limited to a decrease in disc height, osteoporosis of the end plates, without development of the bone block. These changes are often falsely taken for osteochondrosis which leads to diagnostic errors. Page 4 of 21

5 Images for this section: Fig. 1: Spondylodiscitis Th12-L1 as complications after surgeries on the spine (laminectomy Th12-L1, vertebroplasty and transpedicutar fixation Th9,Th10, L2,L3). Page 5 of 21

6 Fig. 2: Spondylodiscitis at the level Th6-Th7 as complications after surgeries on the spine (laminectomy Th6-Th7, transpedicutar fixation Th6,Th9). Page 6 of 21

7 Fig. 3: Relapse of tuberculocis spondylodiscitis in HIV-positive person at the level Th8Th11. Surgery was previously at the levels Th9-Th10 and Th12-L1. Page 7 of 21

8 Findings and procedure details The main imaging findings of spondylodiscitis on CT: On the early stages: -reduction of the intervertebral disc height; - decrease in the density of the intervertebral disc. After 1-3 weeks: -thickening of the paravertebral soft tissues, which can lead to compression of the nerve roots at the neural foramen; -destruction of adjacent end plates; -deossification of bone with loss of normal architectures of the trabecular bone Also may be seen: -soft tissue replacement of the bone After treatment: -osteosclerosis; -the formation of a bone block from the adjacent vertebral bodies. Normal 0 false false false RU X-NONE X-NONE MicrosoftInternetExplorer4 The main imaging findings of spondylodiscitis on MRI: T1 low(fluidlike) signal in disc space low signal in adjacent endplates T2: (fat sat or STIR) High (fluidlike) signal in disc space Vertebral bodies with high signal intensity loss of low signal cortex at endplates Page 8 of 21

9 paravertebral tissues have high signal intensity DWI (can help to distinguish the acute stage from the chronic stage of the disease) hyperintense in the acute stage hypointense in the chronic stage The table number 1 shows the comparison of some types of spondylodiscitis depending on their etiology. Infection organism Characteristics Bacterial The process often grabs the disc and two adjacent vertebrae in the lumbar, thoracic and cervical spine, relatively rarely observed in craniospinal, thoracolumbar and lumbosacral junctions; Rarely can be seen defeat of one vertebra, combined with a primary lesion of the posterior portions of the vertebrae (intervertebral joints, arches, transverse process); Occasionally there is multiple vertebral osteomyelitis involving the body and discs on multiple levels Tuberculosis Progresses indolently, without acute pain and leukocytosis; Involves adjacent vertebrae(subligamentous spread); Foci of rarefaction predominantly occurs in the anterior parts of two adjacent vertebral bodies; More often infection spreads subligamentally with the formation of large paravertebral abscess; The evident reactive sclerosis can't be seen at the edges of the vertebral bodies and ligaments; Most often in the thoracic spine; Page 9 of 21

10 Frequent damage of arches and other parts of the back structures; In the late stage - formation of angulate kyphosis deformation. Fungal Multiple foci of destruction in the bodies of the vertebrae, which are surrounded by a ring of sclerotic tissue Consistent involvement of several vertebrae, transverse and spinous processes, ribs and other bones A significant incidence of pathological fractures and the relative safety of intervertebral space Chronic disease progression with an increase in the number of foci of destruction Parasitic(Echinococcosis) Cysts grow in the vertebral body, gradually destroying it. Then, when the cortex is lysed, compound cysts spread in paravertebral soft tissue. Also in the process are involved the transverse process and the edge. Some cysts penetrate into the spinal canal and compresses the spinal cord. Damage is demarcated from healthy tissue with thin sclerotic rim. The disease progresses over the years, gradually increasing ossification of ligaments, periosteal reaction. More often discs are intact. Complications of spondylodiscitis on Computed Tomography and Magnetic Resonance Imaging: Epidural abscess: -CT CT even with contrast can struggle to demonstrate smaller collections -MRI Page 10 of 21

11 Gadolinium-enhanced MRI is the imaging choice for diagnosis of spinal epidural infection. Two main patterns can be seen: 1. phlegmonous stage of infection results in homogeneous enhancement of the abnormal area which correlates to granulomatous-thickened tissue with embedded micro-abscess without a significant pus collection 2. liquid abscess surrounded by inflammatory tissue which shows varying degree of peripheral enhancement with gadolinium Non-contrast MRI can show liquid abscess too - it is the presence of a region of high T2 signal, with low T1 signal and without enhancement (usually surrounded by a rim of enhancement). Paravertebral abscess: Changes in paravertebral tissues can be characterized on CT-imaging as follows: relatively low attenuation central necrotic component with thick capsula circumferentially capsular ring enhancement with contrast surrounding inflammatory changes (i.e. fat seal) Differential diagnosis Possible imaging differential considerations include: Modic type 1 degenerative change (It can resemble spondylodiscities because of the presence of bone marrow edema which has high signal intensity on T2WI. These bone marrow changes may show enhancement on post-contrast images. But such changes as endplate destruction, increased disk signal intensity on T2-weighted images, paravertebral or epidural abscess are specific to spondylodiscitis. Charcot joint. ( On T2-weighted images, the presence a high-signal intensity concentric ring surrounding a cartilaginous node may help distinguish an edematous node from infectious spondylitis) Schmorl nodes - intravertebral disc herniations(mri-imagesusually exhibit the same signal characteristics as the adjacent disc, with a thin rim of sclerosis at the margins. Acute form can demonstrate the surrounding bone marrow oedema and peripheral enhancement. These acute features evolve gradually over months). Langerhans cell histiocytosis is a rare multi-system disease with a wide and heterogeneous clinical spectrum and variable extent of involvement Page 11 of 21

12 (sometimes on diagnostic images may be seen changes from another systems which are typical for LCH and that can help to make the correct diagnosis). On images the first stage presents formation of focus of the lytic destruction, the second stage leads to the formation of pathological fractures and the third corresponds to the stage of repair. The LCH is not characterized by reduced height of the intervertebral disc, and the presence of pronounced osteoporosis. Often differential diagnosis is difficult and the correct diagnosis can be made only after a biopsy). Page 12 of 21

13 Images for this section: Fig. 4: Spondylodiscitis at the level L3-L4 on ##-imaging. Note to such attributes as reduction of the intervertebral (L3-L4) disc height, thickening of the paravertebral soft tissues, destruction of adjacent end plates L3,L4, deossification of bone with loss of normal architectures of the trabecular bone. Page 13 of 21

14 Fig. 5: This image presents acute spondylodiscitis at the level Th6-Th7 with development of kyphotic deformation of the spine and also this image presents spondylodiscitis outcome on level L2-L3 - the formation of a bone block from the adjacent vertebral bodies. Surgery( laminectomy) was on level Th3-Th6 Page 14 of 21

15 Fig. 6: Spondylodiscitis at the level C3-C4 on MRI-imaging. Note to such attributes as T1: low(fluidlike) signal disc space low signal in adjacent endplates T2 and T2 STIR: High (fluidlike) signal in disc space Vertebral bodies with high signal intensity loss of low signal cortex at endplates epidural component and paravertebral tissues have high signal intensity Fig. 7: A patient with spondylodiscitis at the level L3-L4, epidural abscesses at the level L3-L5 (blue arrows) and paravertebral abscess (green and yellow arrows) in the left longissimus thoracis muscle. Page 15 of 21

16 Fig. 8: A patient with spondylodiscitis at the level L3-L4 and its complications - ileo-psoas abscesses (yellow arrow). Page 16 of 21

17 Fig. 9: A patient with drug addiction on these images. Spondylodiscitis at the level Th2Th3 vertebrae. Note to thickened paraspinal soft tissue mass and zone of destruction in S1,S2 of the upper lobe of right lung. Fig. 10 Page 17 of 21

18 Fig. 11: Fig.10, Fig.11 A patient with spondylodiscitis at the level L5-S1 vertebrae with penetration of infection on paravertebral tissues; pyogenic sacroiliitis on the left side and retroperitoneal abscesses(arrows). Page 18 of 21

19 Fig. 12: A patient with spondylodiscitis(green arrows) and epidural abscess(yellow arrows) at the level L2-L3 vertebrae. Page 19 of 21

20 Conclusion CT and MRI images can provide establishing of the correct diagnose of spondylodiscitis, disclosure of an infectious agent and indentifying of the disease complications. Diagnostic images can allow differential diagnosis to distinguish between acute and chronic forms. Page 20 of 21

21 References Mathias Prokop, Michael Galanski. Spiral and Multislice Computed Tomography of the Body. Lukyanenko P. I., Leshchev A. S., A. A. Strelis. MRI in the diagnosis of tuberculous spondylitis: Guide for physicians. - Tomsk:publishing house Veter, P112 Charles, RW, Govender, S, Naidoo, KS (1988) "Echinococcal infection of the spine with neural involvement" Spine13:47-9 L Homagk, N Homagk, HJ Meisel, GO Hofmann, and D Marmelstein. A Spondylodiscitis Scoring System: SponDT -Spondylodiscitis Diagnosis and Treatment. JSM Spine 1(1): 1004 (2016) Page 21 of 21