The Comparison of Lower Extremity Length and Angle between Computed Radiography-Based Teleoroentgenogram and EOS® Imaging System

Abstract

Background and objectives: The differences between computed radiography-based teleoroentgenograms (CR-based teleoroentgenograms) and an EOS® imaging system were evaluated by measuring lower extremity lengths and alignments. Materials and methods: The leg length [L], femur length [F], tibia length [T], and hip–knee–ankle (HKA) angle were measured in 101 patients with lower extremity disease by a CR-based teleoroentgenogram with computed radiography and an EOS®. The additive length of the femoral and tibial segments (F + T) was determined by adding the two length values. Then, the differences among all five parameters between the two techniques were analyzed. The magnification (mm) was calculated by subtracting the length measurements on the EOS® from those in the scanogram. Furthermore, the magnification percentage (%) was calculated by dividing the magnification with the measurements on the EOS®. Results: The magnification errors (mean ± standard deviation), when comparing both right and left sides, were 7.80 ± 1.41%, 7.3 ± 6.01%, 5.16 ± 1.25%, and 6.45 ± 0.94% for L, F, T, and F + T, respectively. For limb length, the CR-based teleoroentgenogram had an average magnification of 6.8% (range, 5.2 to 7.8%) compared to the EOS® imaging. The two groups displayed a statistical difference (p < 0.01), except for the HKA angle. Conclusions: The CR-based teleoroentgenogram had a magnification of about 6.8% compared to the EOS® imaging system in evaluating lower extremity length. Therefore, more attention must be given to CR-based teleoroentgenograms to correct angular deformities.

Does the use of intraoperative measurement reduce limb length discrepancies after total hip arthroplasty?

“…The results showed that around 1/6 of patients exhibited a leg length discrepancy (LLD) exceeding 10 mm when measured from the lesser trochanter [ 25 ]. It was also shown that the average magnification for limb length measurement using Computed Radiography (CR) over EOS imaging was 6.8%[ 26 ]. In addition, it was found that conventional measurements of LLD on AP pelvic radiographs did not correlate well, while the full-length, functional imaging EOS method could provide a better evaluation of LLD [ 27 ].…”

Tibia Multiplanar Deformities and Growth Disturbance Following Expandable Endoprosthetic Distal Femur Replacement

“…Multiplanar deformities are common, but they may not be clinically significant. Statistical significance does not denote clinical significance [7]. Thus, the bulk of cases will seldom necessitate subsequent surgical correction.…”

“…All patients underwent the objective tools of scanogram imaging and computed tomography (CT) scans of both legs to assess longitudinal disturbances and multiplanar deformities; this is to ensure accurate assessment and appropriate alignment after surgery [7]. Several recent papers have used the supine CT scanogram to assess lower limb alignment, which has proved to have higher levels of accuracy compared to other methods.…”

Scoliosis and Lower Limb Inequality: To Lift or Not to Lift, That Is the Question

“…Micro-dose digital radiography is computerized imaging that substantially reduces patients' radiation exposure compared to conventional radiographic techniques. In this method, a relatively old micro-dose digital technique [ 41 ], with a more recent development termed EOS (EOS imaging, Paris, France) [ 42 , 43 ], is used to measure limbs. Using a vertical gantry, the patient stands in front of the X-ray unit and remains still during the 20-second scanning process.…”

“…The source assembly and detector move together in a row-by-row motion so that the beam remains horizontal to the patient. Because the detector is efficient at finding and processing the point source of X-ray photons, the patient exposure, during the scan, was six to nine times lower than that of conventional radiographs and four to 23 times lower than that of CT [ 43 ].…”