Reza Vali MD, Presenter: Nothing to Disclose

MANDY KOHLI, Abstract Co-Author: Nothing to Disclose

Etienne Sochette, Abstract Co-Author: Nothing to Disclose

Amer Shammas MD, Abstract Co-Author: Nothing to Disclose

In children over the age of five, it is recommended that both lumbar spine and total body less head (TBLH) be measured. We have been performing both of these measurements since 2009. The clinical utility of obtaining both measurements remains unclear. The aim of this retrospective study in which both measurement of lumbar spine and TBLH had been obtained in individual cases was to determine whether the relationship between Lumbar and TBLH BMD will permit for a more limited scanning protocol. 

A retrospective review was conducted for all results of Dual energy X-ray Absorptiometry (DXA) studies (Lunar Prodigy) (3128 studies) from 2010.01.01 to 2013.06.30 in patients (n=2005) who had both TBLH and lumbar assessment. DXA studies were interpreted as reduced BMD when the Z-score of either lumbar spine or TBLH or both were equal or less than - 2.0. The clinical indications for the patients were categorized into 14 major groups including: metabolic, endocrine, cancers (leukemia,…), steroid therapy, kidney disease, gastrointestinal problems, inflammatory disease (vasculitis,..), restricted diet (anorexia nervosa,..), on medication (Coumadin,…), primary bone disorder (osteogenesis imperfecta,..), post-transplantation, immobility (cerebral palsy,..), history of multiple fracture and others (developmental disorders, genetic syndromes,…).

272 of the 2005 patients showed reduced BMD in at least one of their DXA studies. 100 patients showed reduced BMD only in the lumbar spine, 37 only in the TBLH and 135 in both. In those (n=37)who had reduced BMD only in TBLH, the Z-score in the lumbar spine was between -1.0 to -2.0 in 32 and between 0 to -1.0 in 5 patients. All 5 patients who had a reduced BMD on TBLH and lumbar Z score between 0 to -1.0 belonged to the immobility (non-ambulatory) group. There was no case in which TBLH was reduced with a lumbar Z-score equal or more than zero. 

The frequency of reduced BMD only on TBLH is very low if the lumbar spine Z score is greater than -1.0. In order to minimize imaging time and decrease radiation exposure, it may be suggested to start with a lumbar spine BMD assessment and to proceed with TBLH evaluation only if the lumbar Z-score is less than -1.0 or if the patient has a history of immobility including cerebral palsy. 

This study reviews the most common indications of DXA scan in children and suggest a more cost effective techique.

Vali, R, KOHLI, M, Sochette, E, Shammas, A, Bone Mineral Density in Children: Total Body Less Head,or Lumbar Spine Measurements or Both?.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018060.html