To optimize our Full Spine Radiograph protocol used in the follow up of children with idiopathic scoliosis.
METHOD AND MATERIALSWe performed a lowered dose posterioranterior (PA) full spine radiograph in 40 patients (protocol B) with idiopathic scoliosis aged 10-16 years (10 males;30 females) on a Luminos dRF (Siemens). Dose reduction was achieved by adding a 0.2 mm cupper filter and lowering the tube intensity. Radiographs were scored on 6 criteria (5-point Likert scale) by a pediatric radiologist and a pediatric orthopedist who were blinded to patient identity and clinical information. The scored criteria were bone/soft tissue contrast, bone sharpness, visibility of processus spinosis, delineation of the intervertebral spaces, assessment of the spinal curve and Risser grade, representing a total score between minimal 6 and maximal 30 points. These scores were compared to the scores of 40 PA full spine X-ray’s performed in 2013 with our standard protocol (protocol A) again in patients aged between 10 and 16 years with idiopathic scoliosis (7 males;33 females). Tube intensity, entrance dose (D) and dose area product (DAP) were compared. Statistical analysis was performed using IBM SPSS (v23) and included assessment of DAP, D, tube intensity, image quality score and interobserver variability by intraclass correlation coefficients (ICC). A p value of less than 0.05 was considered significant.
RESULTSMean age was 13,3 ± 1.6 years for group A and 13.4 ± 1.7 years for group B. For protocol A the mean tube intensity was 1.3 ± 0.4 mAs, the mean D was 5.0 ± 1.8 mGy and the mean DAP was 85.3 ± 32.7 µGy.m2. With protocol B, exposure parameters reduced to: tube intensity 0.7 ± 0.4 mAs, D 2.8 ± 1.3 mGy and DAP 47.0 ± 22.4 µGy.m2 (all p<0.05). Mean image quality score for protocol A was 28.1 ± 2.4 points (range 21-30), comparable to the mean total score of protocol B 27.9 ± 2.3 points (range 22-30). Interobserver agreement was excellent (ICC 0.92).
CONCLUSIONThis study demonstrates that a lowered dose (45%) full spine radiograph can be performed in patients with idiopathic scoliosis by adding a 0.2 mm Cu filter and lowering tube intensity without loss of image quality.
CLINICAL RELEVANCE/APPLICATIONDose optimization is a key aspect in pediatric radiology, in particular with patients receiving recurrent radiographs.