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

Transition metal selenide nanodots (NDs) represent distinctive antitumor agents for cancer treatment, but their non‐biodegradability may bring serious adverse effects and potential long‐term toxicity to internal tissues/organs, which substantially hinder their further clinical translations. In this work, the construction of a multifunctional theranostic nanosystem based on degradable and excretable ultrasmall Rh3Se8 NDs by a general bovine serum albumin‐templated strategy is reported. The constructed Rh3Se8 NDs exhibit distinctively high photothermal‐conversion efficiency (57.5%) in the second near‐infrared biowindow, making them highly applicable for photoacoustic imaging and photonic hyperthermia at the desired wavelength. Rh3Se8 NDs exhibit a high tumor growth inhibition rate (98.1%) on 4T1 breast tumor‐bearing mice due to the desirable photonic hyperthermia performances. Especially, the fabricated Rh3Se8 NDs feature the large X‐ray attenuation coefficients of the Rh component for contrast‐enhanced X‐ray computed tomography imaging. Importantly, the prominent biodegradability of Rh3Se8 NDs enables their quick excretion out of the body for potentially avoiding inflammation and mitigating long‐term toxicity. Therefore, this work highlights the construction of proof‐of‐concept biodegradable and excretable ultrasmall inorganic theranostic nanosystems for multiple bioimaging‐guided cancer nanotherapeutics, guaranteeing the further clinical translations of inorganic nanoparticles in biomedicine.

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Background: To evaluate the diagnostic value of quantitative parameters [T1, T2, and proton density (PD) value] generated from magnetic resonance image compilation (MAGiC) sequence for active sacroiliitis in the patients with axial spondyloarthritis (ax-SpA).Methods: A total of 90 consecutive ax-SpA patients were recruited and divided into an active group (n=48) and inactive group (n=42) based on the Spondyloarthritis Research Consortium Canada (SPARCC) score in this prospective study. In addition, 47 healthy volunteers were recruited as the control group. All participants underwent magnetic resonance (MR) scanning (including MAGiC sequence and T2 mapping sequence) to obtain the T1 value, T2 value, PD value of MAGiC sequence (MAGiC T1 value, T2 value, PD value), and the T2 value of T2 mapping sequence (T2 map T2 value). Intraclass correlation coefficients (ICC) were calculated to assess the inter-and intra-observer agreement. The correlation between the MAGiC T2 value and the T2 map T2 value was analyzed using Spearman's Rho. One-way analysis of variance (ANOVA) and receiver operating characteristic (ROC) analysis were performed for all parameters.Results: For the active group, inactive group, and control group, the MAGiC T1 value, T2 value, PD

To the Editor: Axial spondyloarthritis (axSpA) is characterized by sacroiliac joint inflammation, spine inflammation, bone destruction, and osteogenesis. Ankylosis of the spine and/or hip joints may occur later, significantly affecting the patient's quality of life. As the earliest and most common imaging finding of axSpA, sacroiliitis can be divided into early active and late structural lesions. Magnetic resonance imaging (MRI) not only detects active inflammatory changes that cannot be found in computed tomography (CT) or X-rays but also has a similar sensitivity to CT in detecting structural lesions. [1] However, conventional MRI only provides the qualitative diagnosis of sacroiliac joint lesions but does not provide quantitative information. Objective, accurate, and repeatable quantitative assessment, especially for bone marrow edema (BME) and fat metaplasia, which are associated with disease prognosis, offers potential imaging methods to evaluate the state of illness and therapy efficacy. Synthetic MRI, as a new imaging technique, provides both qualitative and quantitative information based on the same scan. In the present study, we aimed to verify whether synthetic MRI provides the similar qualitative diagnostic value of sacroiliac joint lesions in patients with axSpA compared with conventional MRI and to assess the quantitative diagnostic performance of quantitative maps generated by synthetic MRI in the detection of BME and fat metaplasia in the sacroiliac joint. To our knowledge, this study is the first to investigate the potential practicality of synthetic MRI for assessing sacroiliac joint lesions in participants with axSpA.Ke Zhang and Jing Zheng contributed equally to the work.