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.

Role of Bone Scan and MRI in Designing of Customized Prosthesis for Limb Salvage Surgery of Long Bone Tumors: 4 Years of Single Institution Analysis.

The purpose of this study is to evaluate the role of bone scan (BS) and MRI measurement data in designing Custom Made Prosthesis (CMP) in Limb Salvage Surgery (LSS) in orthopedic oncology patients. The study was done on 126 patients, which include 88 males and 38 females. Pre-operative planning including determination of the osteotomy plane and dimension of the prosthesis was performed based on Tc99m MDP bone scan and MR images comparing with the histopathology examination (HPE) values. 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. Bone scan and HPE values are positively correlated; p value is 0.913 (p < 0.001). However, mean difference between the HPE and bone scan is statistically significant (p < 0.001). MRI scan and HPE values are positively correlated 0.920 (p < 0.001) and mean difference is also statistically not significant (0.920; p < 0.001). If we apply ± 20% window, 94/126 patients (75%) bone scan measurements and 94/112 patients (84%) MRI measurements are matching with the HPE measurements. We conclude that bone scan measurements were found to be more or less equal to MR imaging for determining the tumor extent for the fit of the prosthesis and excellent functional results.

Prediction of postoperative pulmonary reserve in lung resection patients.

UNLABELLED: We performed Ventilation/Perfusion scans for patients planned for thoracotomy with resection of the primary or metastatic lung tumors. We predicted the post-operative FEV1 (Forced Expiratory Volume in first second) using Differential Lung Analysis software. METHODS: 34 patients were evaluated with Ventilation/Perfusion (V/Q) scans. Ventilation scan was performed with Tc-99m DTPA Aerosol and Perfusion Scan with Tc99m MAA, on 2 different days. The numbers of counts in anterior and posterior views of V/Q scans were calculated individually. Anterior and posterior arithmetical mean was calculated and post-operative FEV1 was predicted with the use of Differential Lung Analysis software. In most of the patients, the counts in the ventilation scan were lower and they were related to preoperative FEV1. Depending on the volume of lung resection, i.e. Upper, Middle and Lower zones or Total Pneumonectomy, FEV1 was calculated. Whenever FEV1 was >0.8 (L), the patient was taken up for resection (and if there were no other risk factors, such as cardiac complications, chronic obstructive pulmonary diseases, and any other pathological conditions involving the contralateral lung). RESULTS: Most of the 34 patients were taken up for lung resection based on our FEV1 predictions. In 7 patients, repeat spirometry (i.e. pulmonary function test) was done at varying intervals after surgical procedures and the variation between preoperative FEV(1) and postoperative FEV(1) was only ±15%, at the most. CONCLUSION: Postoperative FEV(1) based on V/Q scan and pulmonary function tests helped us to proceed with lung resection after assessment of the pulmonary reserve.