Marianne Alison MD, PhD, Presenter: Nothing to Disclose

Emmanuelle Ferrero, Abstract Co-Author: Nothing to Disclose

Anca Sorina Tanase MD, Abstract Co-Author: Nothing to Disclose

Adelaide Rega, Abstract Co-Author: Nothing to Disclose

Brice Ilhareborde, Abstract Co-Author: Nothing to Disclose

Kevan Mazda MD, PhD, Abstract Co-Author: Nothing to Disclose

Guy Henri Sebag MD, Abstract Co-Author: Nothing to Disclose

For the follow up of spinal deformities, a novel biplanar slot scanning system has been shown to allow significant dose reduction. Further dose reduction can be obtained with recent technical advances (copper filtration and dedicated image processing) and with the optimization of the acquisition parameters (kV, mA and scan speed). Our aim was to assess the image quality as well as the reproducibility of clinical parameter measurements using an optimized ultra low dose protocol for scoliosis examinations  

23 patients (mean age: 12.4 yo ± 3.3, range 5-18yo) with mild or moderate idiopathic scoliosis were imaged with an ultra low dose protocol optimized according to the body mass index, following the ALARA concept. Dose Area product (DAP) and entrance dose (kerma) were quantified for each examination. Image quality was rated on a 5-point scale based on the visibility of the edges of the vertebrae of 5 different anatomical areas (cervical, superior and inferior thoracic and lumbar spine), 5 corresponding to the highest quality. Cobb angle, cervical and lumbar lordosis, thoracic kyphosis, pelvic parameters (pelvic incidence, sacral slope) were measured by two independent operators (radiologist and orthopedist). The intraclass correlation coefficient (ICC) was used to assess interobserver agreement of the measurements.  

Mean (±SD) Cobb angle was 22.3 (± 13)°. Mean DAP was 39.5 (± 17.1) and 87.9 (± 31.7) mGy.cm2 for the antero posterior (AP) and the lateral view respectively. Mean entrance doses was 17.6 (±6.4) and 42.1(±12.8) µGy for the AP and the lateral view respectively. This dose corresponds to approximately 10 days of background radiation. Image quality was graded 3 in 11/23 (48%) cases, 4 in 11/23 (48%) cases and 5 in 1/23 (4%) case. Interoberver agreement was very high for Cobb angle (ICC 0.92), T1-T12 kyphosis (ICC 0.90) and L1-S1 lordosis (ICC 0.90) and high for cervical lordosis (ICC 0.89), T4-T12 kyphosis (ICC 0.89), pelvic incidence (ICC 0.88) and sacral slope (ICC 0.83).  

Ultra low dose imaging is achievable for the follow up of idiopathic scoliosis, with acceptable image quality and high reproducibility of the measurements.

Ultra low dose protocol using biplanar slot scanning system with optimized acquisition parameters can be used for the monitoring of idiopathic scoliosis, allowing further dose reduction

Alison, M, Ferrero, E, Tanase, A, Rega, A, Ilhareborde, B, Mazda, K, Sebag, G, Ultra Low Dose Imaging for the Follow up of Idiopathic Scoliosis: How Low is Reasonably Achievable with New Slot-scan Technology ?.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13018367.html