The clinical test results show that the SCN800 series is highly consistent with the X-ray, with a linear correlation of 0.94, similar results have also been published in SCI articles (Lee TT, Lai KK, Cheng JC, Castelein RM, Lam TP, Zheng YP. 3D ultrasound imaging provides reliable angle measurement with validity comparable to X-ray in patients with adolescent idiopathic scoliosis. Journal of Orthopaedic Translation. 29:51-59, 2021).
In our clinical trials and studies, we measured two angles to facilitate comparison. X-rays can actually show 3 to 4 angles, some in the neck and bottom area. Ultrasound images can also measure angles near the neck like an X-ray.
But we need to consider: Firstly, we need to cover the neck area during the scan. (However sometimes the operator may not cover T1 during scanning, so it is difficult to measure the angle close to the neck); Secondly, sometimes the angle can pass through the upper chest and neck, so the angle may still be difficult to measure even if T1 is scanned.
In general, the neck area is narrow and difficult to scan, so normally the operator does not scan over the neck area. Even though we can use ultrasound images for measurements (and X-rays too), the neck moves easily when scanning, so the angle cannot be very accurate. When we change the posture of the neck a little, the angle can change a lot. We have heard from some clinicians who are experts in scoliosis, they do not care so much about the angle of the upper chest and neck area.
The following images compare 5 ultrasound and X-ray clinical measurement examples: