Influence of Accuracy and Precision of Measurements of Long Bone Tumors in Imaging Studies-A Retrospective Study in Musculoskeletal Oncology.

The aim of this study is to evaluate the level of accuracy and precision of bone scan (BS), MRI, and digital radiography (DR) to measure long bone tumors to design custom-made prosthesis (CMP)/modular prosthesis (MP) in limb salvage surgery (LSS) with the help of phantom and patient's study. There are two separate groups: one is the phantom study and another one is the patient's study. The phantom study is done with the Jaszack Phantom for the Gamma camera and the indigenous phantom for the MRI and DR. Three independent imaging professionals (nuclear medicine physicians and radiologists) measured the distance between standardized, preselected points on the Jaszack phantom in the Gamma Camera (GC) and indigenous phantom on the coronal and sagittal view of the MRI scan and in digital radiography. The measured values were compared with the known values for phantom measurement. A total of 36 patients, which include 24 males and 12 females, 3 independent imaging professionals measured the patient's long bone in a bone scan, MRI and DR and compared it with histopathological specimen measurement after limb salvage surgery (LSS). Descriptive statistics using appropriate measures of central tendency and dispersion were employed to describe the data. Karl-Pearson correlation coefficient was used to establish the association between continuous covariates. Paired t-test was utilized to test the differences in paired values for statistical significance. A near-perfect positive correlation was evident between all three pairs of bone scan, MRI scan, and digital radiography values, and a positive agreement within 1 mm of the bone scan, MRI scan, and DR values of all three pairs was around 95%. For the phantom study, we conclude that Gamma camera and MRI measurements are equal in physical measurements (MCF-1). DR measurements were found to be near equal physical measurements and multiplication correction factor (MCF)-0.9104 and three observer's measurements values were also near normal. For the patient's study, we conclude that the bone scan, MRI, and DR measurements of 3 independent imaging professionals are near normal, and it was confirmed with pathological specimen after LSS, to confirm reliability, repeatability, reproducibility, and accuracy of the tumor length to do custom-made prosthesis or modular prosthesis for the patients who are affected by osteosarcoma and Ewing's sarcoma.