Background Differentiating chondrosarcoma from enchondroma using conventional MRI remains challenging. An effective method for accurate preoperative diagnosis could affect the management and prognosis of patients. Purpose To validate and evaluate radiomics nomograms based on non‐enhanced MRI and clinical risk factors for the differentiation of chondrosarcoma from enchondroma. Study Type Retrospective. Population A total of 103 patients with pathologically confirmed chondrosarcoma (n = 53) and enchondroma (n = 50) were randomly divided into training (n = 68) and validation (n = 35) groups. Field Strength/Sequence Axial non‐contrast‐enhanced T1‐weighted images (T1WI) and fat‐suppressed T2‐weighted images (T2WI‐FS) were acquired at 3.0 T. Assessment Clinical risk factors (sex, age, and tumor location) and diagnosis assessment based on morphologic MRI by three radiologists were recorded. Three radiomics signatures were established based on the T1WI, T2WI‐FS, and T1WI + T2WI‐FS sequences. Three clinical radiomics nomograms were developed based on the clinical risk factors and three radiomics signatures. Statistical Tests The area under the receiver operating characteristic curve (AUC) was used to evaluate the performance of radiomics signatures and clinical radiomics nomograms. Results Tumor location was an important clinical risk factor (P < 0.05). The radiomics signature based on T1WI and T1WI + T2WI‐FS features performed better than that based on T2WI‐FS in the validation group (AUC in the validation group: 0.961, 0.938, and 0.833, respectively; P < 0.05). In the validation group, the three clinical radiomics nomograms (T1WI, T2WI‐FS, and T1WI + T2WI‐FS) achieved AUCs of 0.938, 0.935, and 0.954, respectively. In all patients, the clinical radiomics nomogram based on T2WI‐FS (AUC = 0.967) performed better than that based on T2WI‐FS (AUC = 0.901, P < 0.05). Data Conclusion The proposed clinical radiomics nomogram showed promising performance in differentiating chondrosarcoma from enchondroma. Level of Evidence 4 Technical Efficacy Stage 2

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Objective: To construct carcinoma vascular endothelial-targeted polymeric nanomicelles with high magnetic resonance imaging (MRI) sensitivity and to evaluate their biological safety and in vitro tumor-targeting effect, and to monitor their feasibility using clinical MRI scanner.Method: Amphiphilic block copolymer, poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) was synthesized via the ring-opening polymerization of ε-caprolactone (CL) initiated by poly(ethylene glycol) (PEG), in which cyclic pentapeptide Arg-Gly-Asp (cRGD) was conjugated with the terminal of hydrophilic PEG block. During the self-assembly of PEG-PCL micelles, superparamagnetic γ-Fe2O3 nanoparticles (11 nm) was loaded into the hydrophobic core. The cRGD-terminated γ-Fe2O3-loaded polymeric micelles targeting to carcinoma vascular endothelial cells, were characterized in particle size, morphology, loading efficiency and so on, especially high MRI sensitivity in vitro. Normal hepatic vascular endothelial cells (ED25) were incubated with the resulting micelles for assessing their safety. Human hepatic carcinoma vascular endothelial cells (T3A) were cultured with the resulting micelles to assess the micelle uptake using Prussian blue staining and the cell signal intensity using MRI.Results: All the polymeric micelles exhibited ultra-small particle sizes with approximately 50 nm, high relaxation rate, and low toxicity even at high iron concentrations. More blue-stained iron particles were present in the targeting group than the non-targeting and competitive inhibition groups. In vitro MRI showed T2WI and T2 relaxation times were significantly lower in the targeting group than in the other two groups.Conclusion: γ-Fe2O3-loaded PEG-PCL micelles not only possess ultra-small size and high superparamagnetic sensitivity, also can be actively targeted to carcinoma vascular endothelial cells by tumor-targeted cRGD. It appears to be a promising contrast agent for tumor-targeted imaging.