Peter Newton, Abstract Co-Author: Research Grant, EOS imaging SA

Fredrick Reighard, Abstract Co-Author: Institutional Research Grant, EOS imaging SA

Quinn Colin Meisinger MD, Presenter: Nothing to Disclose

Carrie Bartley MA, Abstract Co-Author: Institutional Research Grant, EOS imaging SA

Tracey Bastrom, Abstract Co-Author: Institutional Research Grant, EOS imaging SA

Burt Yaszay, Abstract Co-Author: Institutional Research Grant, EOS imaging SA

To evaluate the reliability of 3D spinal reconstructions from EOS x-rays utilizing a 5-fold reduction in radiation dosage compared to standard EOS images utilized for evaluating patients with adolescent idiopathic scoliosis (AIS).   

After IRB approval, 30 AIS patients (20 non-op, 10 post-op) who received “standard”, biplanar, anteroposterior and lateral spine x-rays in our EOS imaging unit (~ 0.31mGy) as part of their routine care, also underwent an additional set of “microdose” EOS x-rays (~ 0.06 mGy) using a new protocol. All subjects had a major Cobb angle greater than 20° (non-operative cohort) or a prior posterior spinal fusion with instrumentation (post-operative cohort). A single reviewer created full 3D reconstructions once of each set of images using sterEOS software. Coronal (Cobb angles), sagittal (T1-T12, T4-T12, L1-L5, L1-S1), and apical axial rotation measurements were obtained. Intraclass correlations (ICC) and the 95% confidence intervals for the differences between the standard and microdose EOS image measurements were compared.  

The average ICC was 0.95 for both the non- and post-operative groups (range 0.89-0.99). The calculated differences for all coronal and sagittal measurements were statistically similar in the non-operative group (p>0.05). In the post-operative group, all measurements were statistically similar, with the exception of T1-T12 kyphosis, which measured greater in the microdose x-rays (45° vs 42°, p=0.001). The error in measurement between standard and microdose images can be found in the Table.  

Good reliability was found between 3D measurements of the standard x-rays and the microdose x-rays in patients with idiopathic scoliosis. A small difference in measurements was observed for T1-T12 kyphosis in the post-operative group possibly suggesting slightly greater difficulty in visualizing the spine in patients after spinal fusion with instrumentation. Further study is underway with a goal of 30 subjects per group; however there is a strong suggestion that radiation exposure can be further reduced with EOS imaging in scoliosis patients. 

For scoliosis patients, standard EOS imaging offers reduced radiation exposure; it appears further reduction by another 5-fold is possible while maintaining reliability of 3D deformity measurements.

Newton, P, Reighard, F, Meisinger, Q, Bartley, C, Bastrom, T, Yaszay, B, Reliability of sterEOS 3D Scoliosis Measurements Using a 5 Fold Reduction in Radiation.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045804.html