Browsing by Author "Rajković, Stanislav (56711148400)"

Background: Computational analysis of routinely acquired MRI has potential to improve the tumor chemoresistance prediction and to provide decision support in precision medicine, which may extend patient survival. Most radiomic analytical methods are compatible only with rectangular regions of interest (ROIs) and irregular tumor shape is therefore an important limitation. Furthermore, the currently used analytical methods are not directionally sensitive. Purpose: To implement a tumor analysis that is directionally sensitive and compatible with irregularly shaped ROIs. Study Type: Retrospective. Subjects: A total of 54 patients with histopathologic diagnosis of primary osteosarcoma on tubular long bones and with prechemotherapy MRI. Field Strength/Sequence: A 1.5 T, T2-weighted-short-tau-inversion-recovery-fast-spin-echo. Assessment: A model to explore associations with osteosarcoma chemo-responsiveness included MRI data obtained before OsteoSa MAP neoadjuvant cytotoxic chemotherapy. Osteosarcoma morphology was analyzed in the MRI data by calculation of the nondirectional two-dimensional (2D) and directional and nondirectional one-dimensional (1D) Higuchi dimensions (Dh). MAP chemotherapy response was assessed by histopathological necrosis. Statistical Tests: The area under the receiver operating characteristic (ROC) curve (AUC) evaluated the association of the calculated features with the actual chemoresponsiveness, using tumor histopathological necrosis (95%) as the endpoint. Least absolute shrinkage and selection operator (LASSO) machine learning and multivariable regression were used for feature selection. Significance was set at <0.05. Results: The nondirectional 1D Dh reached an AUC of 0.88 in association with the 95% tumor necrosis, while the directional 1D analysis along 180 radial lines significantly improved this association according to the Hanley/McNeil test, reaching an AUC of 0.95. The model defined by variable selection using LASSO reached an AUC of 0.98. The directional analysis showed an optimal predictive range between 90° and 97° and revealed structural osteosarcoma anisotropy manifested by its directionally dependent textural properties. Data Conclusion: Directionally sensitive radiomics had superior predictive performance in comparison to the standard nondirectional image analysis algorithms with AUCs reaching 0.95 and full compatibility with irregularly shaped ROIs. Evidence Level: 3. Technical Efficacy: Stage 1. © 2022 International Society for Magnetic Resonance in Medicine.

Aim: This study evaluates the effects of three surgical procedures in the treatment of pronation deformities of the forearm in cerebral palsy patients; namely the transposition of pronator teres to extensor carpi radialis brevis muscle; and rerouting of the pronator teres muscle with or without pronator quadratus muscle myotomy. Methods: Sixty-one patients, 48 male/13 female, with a mean age of 17 years (5-41 years) were treated between 1971 and 2011. Pronator teres transposition was performed in 10, pronator rerouting in 35, and pronator rereouting with pronator quadratus myotomy in 16 patients. Ranges of motion, and assessments using the Quick Dash, Mayo Scoring, and Functional Classification system of upper extremity, were made before and after surgery. Mean follow-up was 17.5 years (3-41 years). Results: All three procedures led to significantly improved ranges of motion and upper limb function, with good/excellent results in 80 % of patients. Mean active supination improved from 10 ° (0-60 °) to 85 ° (30-90 °) (p < 0.001). There were significant improvements in Functional Classification system for the upper extremity scores (p < 0.003), Mean Quick Dash Scores improved from 58.41 (38.63-79.54) to 44.59 (27.27-68.18), and mean MEPS improved from 68 (30-85) to 84 (60-100) following surgery. All three techniques had statistically improved MEPS following surgery (p < 0.001); only the pronator teres muscle rerouting with pronator quadratus myotomy showed an improved Functional Classification system for the upper extremity score (p < 0.05); and only the pronator teres rerouting procedure showed an improved Quick Dash score (p < 0.05). There were no statistically significant differences in outcomes between different ages groups, and no significant differences between isolated pronator teres muscle rerouting were compared with those undergoing simultaneous treatment of carpal flexion and thumb adduction deformities (p > 0.05). Conclusion: Surgery is very effective in the management of pronation deformities of the forearm in patients with cerebral palsy. Isolated pronator teres rerouting is probably the most effective and simple technique. Adjunctive pronator quadratus myotomy does not lead to an improvement in the results and requires an additional surgical approach. There should be no age restriction to surgery, as all age groups appear to benefit from similar improvements in range of motion and upper limb function. © 2015 Čobeljić et al.