28/02/2016. Overview. Interpreting and reporting DXA scans. BMD measurement by DXA. World Health Organisation diagnostic criteria

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1 Overview Interpreting and reprting DXA scans Nicla Peel DM FRCP DXA technique Clinical interpretatin Principles f effective reprting Cnsultant and Hnrary Senir Lecturer in Metablic Bne Medicine Sheffield Teaching Hspitals NHS Fundatin Trust nicla.peel@sth.nhs.uk BMD measurement by DXA Strng predictr f fracture risk Lw X-ray dse Clinically relevant skeletal sites Spine, hip, frearm Vertebral imaging What d all the numbers mean? Wrld Health Organisatin diagnstic criteria BMD T scre Diagnsis >-1 Nrmal <-1, >-2.5 Ostepenia <-2.5 Osteprsis Increasing fracture risk WHO criteria defined fr: BMD measurements f the spine, hip r frearm using phtn absrptimetry Pstmenpausal wmen May nt be applicable fr: Other bne measurement techniques Other ppulatins Men Premenpausal wmen T-scres must nt be used befre skeletal maturity 1

2 Vertebral fracture assessment by DXA Cntext Aim f the DXA reprt Rapid acquisitin Lw X-ray dse 1% f standard X-rays Assess at same time as BMD management by the nn- Wh is the reprt fr? Referrer Patient BMD team fr future reference What is the reprt fr? Cmmunicate result Explain result t referrer, patient, thers Medical recrd Educatin Apprach t DXAinterpretatin Enable cnfident and cmprehensive expert recipient Finding the clues where t lk Is the measurement reliable? What des the DXA result tell us abut fracture risk? What ther factrs need t be taken int accunt? Is the patient at high risk f Referral & GP summary DXA & ther imaging DXA peratr Risk factr questinnaire Labratry tests Medical recrds fracture? Weigh up the evidence - DXA Check reliability Are any technical issues crrectable? Decide what t reprt Infrmatin frm DXA abut fracture risk Bne mineral density Skeletal size and BMI Critical appraisal f the DXA image Reliable spine scan Straight Vertebrae crrectly identified N bne r sft-tissue artefacts Prgressive caudal increase in area, BMC & BMD 2

3 Critical appraisal f the DXA image Spine BMD may be verestimated Reliable hip scan Crrectly psitined As a result f degenerative change Rtatin, abduc tin Regin f interest and analysis crrect N bne r sft tissue artefacts Spine BMD may be verestimated Spine BMD may be verestimated If a vertebral fracture is nt excluded But this may nly be apparent frm ther imaging: Spine BMD may be verestimated Spine BMD may als be underestimated Surgery Artic calcificatin Cngenital anmalies End-plate fractures Neplasm Small skeletal size L3 & L4 Laminectmy BMAD1 Spina bifida 1. Smith et al, J Clin Densitm. 2006;9:114 3

4 DXA cannt differentiate steprsis frm stemalacia Sft tissue abnrmalities affect BMD 51 year ld wman Vegan Husebund by severe mental health prblems 2012: T scre : T scre -2.3 Cntrast media Hip BMD affected by aberrant psitining, analytical errrs and sft tissue anmalies Obesity Gastric band prt Interpretatin f change in BMD Has there been a change in BMD between scans? Greater than least significant change? Validity? Cnfunders? Is the change unexplained? Time between scans Age, weight, mbility Menpausal status & HRT Medicatin Risk factrs Reliable OA affecting abductin & rtatin Analysis includes t much crtical femral shaft Obesity with fat aprn ver FN Weigh up the evidence - risk factr prfile Deliver the verdict the reprt Risk factrs fr fracture, especially thse acting Cmprehensive, cncise, clear independently f BMD Gluccrticids, prir fracture, increased falls risk Vertebral fractures highly predictive Include nly detail that is reliable and pertinent Only 30% present clinically 10 year prbability Rle fr vertebral fracture assessment (VFA) scans High / mderate / lw Bigraphy BMD results Quantify risk f fracture Factrs affecting management Cmpnents Management advice Tec hnic al v alidity WHO c ategry & Read c de Clinical risk factrs Clinical interpretatin Recmmendati ns Frac ture his try GI symptms, renal impairment 4

5 Management advice Treatment T-scre threshlds and 10-year abslute fracture risk Cnsideratin f independent risk factrs Awareness f guidance Lifestyle mdificatin Further investigatin and nward referral Advice abut falls risk Fllw-up recmmendatins Generally minimum 2 years Tlkit / envirnment Standard perating prcedure Template Standard phrases Gvernance Training and CPD QA f scanning and reprting Frum fr peratrs & reprters t meet Stakehlder invlvement Ensure utput is fit fr purpse Lcal management agreements Quality cntrl Key messages Peer review Audit Feedback frm referrers Duble reprting Remember the remit f the DXA reprt Enable expert management by the nn-expert recipient Always evaluate the DXA image Make use f all available evidence Make clear recmmendatins 5