Imaging of the Spine Dr Nicola Bees Consultant Radiologist
Imaging of the Spine Types of Imaging available Value of Imaging in back pain With red flags Without red flags Imaging Guidelines Terminology
Which investigation? Xray MRI CT is not useful as a first line except for trauma and should not be requested from primary care. Isotope bone scan not available at CUH but not usually a first line investigation
Source of Exposure Dental X-ray 135g bag of Brazil nuts Chest X-ray Lumbar Spine X-ray CT scan of the head UK annual average radon dose USA average annual radiation dose CT scan of the chest Average annual radon dose to people in Cornwall Whole body CT scan Dose 0.005 msv 0.005 msv 0.02 msv 0.7mSv 1.4 msv 1.3 msv 6.2 msv 6.6 msv 7.8 msv 10 msv Level at which changes in blood cells can be 100 msv readily observed Acute radiation effects including nausea and 1000 msv a reduction in white blood cell count
Comparative Radiation Doses http://www.hpa.org.uk/topics/radiation/understandingradiation/understand ingradiationtopics/dosecomparisonsforionisingradiation/ http://www.hpa.org.uk/topics/radiation/understandingradiation/understand ingradiationtopics/medicalradiation/medic_tedequivalent/
Red Flags Neurological: Sphincter or gait disturbance Severe/progressive motor loss Widespread neurological deficit (Single level nerve deficit) Other: Onset of pain < 20yrs or >55 yrs Previous or current malignancy Systemically unwell Raised CRP HIV Weight loss IV drug abuse Steroids Structural deformity Non-mechanical back pain (no relief with bed rest) Fever Thoracic pain
Metastases Discitis TB Cauda Equina Syndrome
Low Back Pain with no red flags No imaging required. No imaging that will alter management. Can refer to MCATS guidelines for advice on management Can refer to MCATS for triage, assessment and conservative treatment http://www.croydonhealthservices.nhs.uk/mcats.htm
Reasons for not imaging
100 80 HNP % pts with findings at at least one disc level 60 40 20 Stenosis Bulging disc Degen disc 20-39 40-59 60-80 Age (years) Incidence of HNP, spinal stenosis, bulging disc, degenerate disc on MRI of 67 asymptomatic patients Boden et al J. Bone Joint Surg. Am. 72:403-408, 1990.
Lumbar Degenerative Disk Disease Michael T. Modic, MD and Jeffrey S. Ross, MD Radiology 2007;245:43-61 The etiology of pain in degenerative disease is more complex than a simple mechanical explanation. The prognostic value of imaging is confounded by the high prevalence of morphologic changes in the asymptomatic population. In patients with uncomplicated low back pain or radiculopathy, MR imaging may not have an additive value over clinical assessment.
20-28% of asymptomatic patients have disk herniations DG Borenstein et al J Bone Joint Surg Am 2001;83-A:1306 1311. Prevalence of disk herniation in symptomatic patients with Low back pain 57% Radiculopathy 65% Disk herniations esp large ones can dramatically reduce with conservative treatment One third of patients with disk herniation at presentation had significant resolution or disappearance at 6 weeks, two thirds at 6 months Type, size, location of herniation and presentation did not correlate with outcome. In fact presence of herniation on MRI was a positive prognosticator Modic MT, Obuchowski NA, Ross JS, et al. Radiology 2005;237:597 604
Barzouhi et al N Engl J Med 2013;368:999-1007. The natural history of sciatica is favorable, with spontaneous resolution of leg pain within 8 weeks in the majority of patients. During longer follow-up at least 15 to 20% of patients report recurring or persistent symptoms after a first episode of sciatica, regardless of whether they underwent surgery. Even after disk surgery, MRI studies have shown disk herniation in up to 53% of asymptomatic persons.
Barzouhi et al N Engl J Med 2013;368:999-1007. In patients with symptomatic lumbar disk herniation at baseline who were treated with either surgery or conservative treatment and followed for 1 year, the presence of disk herniation on MRI at 1-year follow-up did not distinguish patients with a favorable clinical outcome from those with an unfavorable outcome. Patients asking for reimaging because of persistent or recurrent symptoms should be informed about the difficulty in MRI interpretation after a first episode of acute sciatica.
Acute Low Back Pain and Radiculopathy: MR Imaging Findings and Their Prognostic Role and Effect on Outcome. Modic et al. Radiology 2005; 237:597 604 In typical patients with LBP or radiculopathy, MR imaging does not appear to have measurable value in terms of planning conservative care. Patient knowledge of imaging findings does not alter outcome and is associated with a lesser sense of well-being.
http://www.nice.org.uk/nicemedia/live/11887/ 44343/44343.pdf 1.1.2 Do not offer X-ray of the lumbar spine for the management of nonspecific low back pain. 1.1.3 Consider MRI (magnetic resonance imaging) when a diagnosis of spinal malignancy, infection, fracture, cauda equina syndrome or ankylosing spondylitis or another inflammatory disorder is suspected. 1.1.4 Only offer an MRI scan for non-specific low back pain within the context of a referral for an opinion on spinal fusion.
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Lumbar Spine Imaging technique Pain and suspected osteoporotic collapse spondyloarthropathy in younger patient XR Sciatica: less than 6 weeks with no red flags* Sciatica with no red flags*, not responding to conservative management after 6-8 weeks Pain with red flags* (including foot drop) Imaging not usually indicated MRI MRI (Urgent) and refer for urgent Orthopaedic review. Back Pain in Children/Adolescents Refer to secondary care prior to imaging (usually MRI)
Nice guidelines for Ultrasound of Soft tissue lumps In patients presenting with a palpable lump, an urgent referral for suspicion of soft tissue sarcoma should be made if the lump is: greater than about 5 cm in diameter deep to fascia, fixed or immobile painful increasing in size a recurrence after previous excision. If there is any doubt about the need for referral, discussion with a local specialist should be undertaken.
Reporting terms Segmentation anomaly/transition Vertebra/Lumbarisation of S1/Sacralisation of L5 Bulge/Herniation/Protrusion/Extrusion/Prolapse Spondylolisthesis Degenerative/Spondyloytic Degenerate/Dehydrated/Reduced Signal in Disc Schmorl s nodes/intravertebral disc herniation Haemangioma Narrow spinal canal/spinal canal stenosis Nomenclature and Classification of Lumbar Disc Pathology Recommendations of the Combined Task Forces of the North American Spine Society, American Society. SPINE Volume 26, Number 5, pp E93 E113
Segmentation anomaly/transition Vertebra/Lumbarisation of S1/Sacralisation of L5
Degenerate/Dehydrated/Reduced Signal in Disc Bulge/Herniation/Protrusion/Extrusion/ Prolapse
Disc herniation Left central to subarticular focal disc extrusion
Schmorl s nodes
Spondylolisthesis/Anterolisthesis/Retrolisthesis
Image before referral/refer without imaging Refer to MCATS no need to image first Direct referral to Orthopaedics Request MRI plus bloods (FBC ESR CRP U+Es Cr) Patients with red flags Patients with back pain and specific/single level nerve root symptoms and signs
Summary Beware that in the lumbar spine MRI can correlate poorly with clinical symptoms and can be misleading therefore only image according to the guidelines Rely on clinical assessment to guide imaging and referral