title: Review of comparative studies between bone densitometry and quantitative ultrasound of the calcaneus in osteoporosis.
abstract: OBJECTIVE
  To assess the utility of quantitative ultrasound (QUS) of the calcaneus for diagnosing osteoporosis compared to the gold standard, bone densitometry using dual-emission X-ray absorptiometry (DXA), according to published reports.
  
  
  METHODS
  In this systematic review, the Medline/PUBMED, Medline Ovid and Journals@Ovid, and Wilson General Sciences Full Text database were used. The search strategy involved use of the following MeSH descriptors: [osteoporosis AND (densitometry OR ultrasonography)], and 39 articles published between 2001 and April 2010 were assessed. However, only six articles met the inclusion criteria: sensitivity and specificity of QUS, sample (women or men with no treatment or other disease likely to change bone mass index), devices used, comparative T-score between QUS of the calcaneus and DXA. The GE-Lunar Achilles and Hologic Sahara devices were used in most of the tests reported and were effective.
  
  
  RESULTS
  All studies assessed compared QUS of the calcaneus to DXA of the lumbar spine or femoral neck, as the gold standard. QUS sensitivity ranged from 79% to 93% and specificity ranged from 28% to 90% when at the lower threshold. It is a controversial parameter, because the gold-standard threshold (T-score < -2.5, DXA) could not be used for QUS without errors in osteoporosis diagnosis. All studies had a threshold determined by the authors’ criteria, with a variability of -1.7 (pDXA T--score) and -2.4 for QUS, leading to the same prevalence of osteoporosis, and a T-score of < -3.65 for QUS was equivalent to a T-score < -2.5 for DXA.
  
  
  CONCLUSIONS
  Based on the analysis of seven studies, we conclude that QUS of the calcaneus still cannot be used to confirm diagnosis of osteoporosis by comparing the results to those of patients who had already received such a diagnosis based on DXA. However, further research should be conducted in this area, because it is possible to improve the number diagnoses by varying the cutoff T-score. Furthermore, using QUS of the calcaneus was a helpful tool for assessing pathological fractures, whether or not they were associated with osteoporosis.
authors.affiliation: Orthopedics Department, Faculty of Medical Sciences, Pontifical Catholic University of Campinas, Brazil. mi_floter@hotmail.com
authors.forename: Michelle
authors.initials: M
authors.lastname: Flöter
authors.forename: Cíntia Kelly
authors.initials: CK
authors.lastname: Bittar
authors.forename: José Luis
authors.initials: JL
authors.lastname: Zabeu
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Carneiro
mesh_terms: D015502:Absorptiometry, Photon; D015519:Bone Density; D002111:Calcaneus / Q000000981:diagnostic imaging*; D006801:Humans; D010024:Osteoporosis / Q000000981:diagnostic imaging*; D014463:Ultrasonography