with malignant gliomas. However, almost half of treated patients are resistant to temozolomide and all patients eventually fail the therapy. [4] Due to the limited efficacy of existing therapies, it is important to develop more effective chemotherapeutics for malignant gliomas.Hypoxia, as a common feature in solid tumor, represents a major barrier in gliomas chemotherapy resistance. [5] Manganese dioxide (MnO 2 ) nanoparticles, characterized by the decomposition under acidic tumor microenvironment (TME), have attracted extensive attention as a theranostic system for cancer imaging and therapies. [6][7][8] MnO 2 is highly reactive with hydrogen peroxide (H 2 O 2 ) in acidic TME to produce O 2 and regulate the pH value, which can effectively alleviate tumor hypoxia. In the meantime, Mn 2+ generated during the decomposition of MnO 2 nanoparticles can provide contrast enhancement for T 1 -weighted magnetic resonance imaging (MRI), upon which tumor can be diagnosed and the therapeutic process can be monitored in vivo. [9,10] To date, MRI with contrast enhanced by paramagnetic gadolinium(Gd)-based agents remains an advanced imaging method for gliomas diagnosis in clinic. [11] However, these Gdbased contrast agents are severely limited by the poor visual contrast between normal brain tissue and gliomas, owing to their nonspecific organ or tissue distribution. [12] The TMEresponsive release of Mn 2+ from MnO 2 nanoparticles offers Chemotherapy plays an important role in treating cancers in clinic. Hypoxiamediated chemoresistance remains a major hurdle for effective tumor chemotherapy. Herein, a new class of tLyP-1-modified dopamine (DOPA)β-cyclodextrin (CD)-coated paclitaxel (PTX)-and manganese dioxide (MnO 2 )-loaded nanoparticles (tLyP-1-CD-DOPA-MnO 2 @PTX) is developed to enhance glioma chemotherapy. The nanomedicine delivered to the tumor site decomposes in response to the weak acidity and high hydrogen peroxide in the tumor microenvironment (TME), resulting in collapse of the system to release PTX and generates Mn 2+ and O 2 . In a rat model of intracranial glioma, tLyP-1-CD-DOPA-MnO 2 @PTX can efficiently pass through the blood-brainbarrier to accumulate in tumor sites. The hypoxia in TME can be relieved via O 2 generated by MnO 2 and the reactive oxygen species produced by Mn 2+ can kill tumor cells. The tLyP-1-CD-DOPA-MnO 2 @PTX nanoparticles exert a remarkable antitumor effect by promoting apoptosis and inhibiting proliferation of tumor cells in addition to enabling real-time tumor monitoring with magnetic resonance imaging. This MnO 2 -based theranostic medicine will offer a novel strategy to simultaneously enhance chemotherapy and achieve real-time imaging of therapeutic process in glioma treatment.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smtd.202101531. IntroductionGliomas are the most common type of primary brain tumors. [1] Despite considerable advances in various treatment including surgery, chemotherapy, and radiotherapy, the prognosis...
Objective The relatively long scan time has hampered the clinical use of whole-heart noncontrast coronary magnetic resonance angiography (NCMRA). The compressed sensitivity encoding (SENSE) technique, also known as the CS technique, has been found to improve scan times. This study aimed to identify the optimal CS acceleration factor for NCMRA. Methods Thirty-six participants underwent four NCMRA sequences: three sequences using the CS technique with acceleration factors of 4, 5, and 6, and one sequence using the conventional SENSE technique with the acceleration factor of 2. Coronary computed tomography angiography (CCTA) was considered as a reference sequence. The acquisition times of the four NCMRA sequences were assessed. The correlation and agreement between the visible vessel lengths obtained via CCTA and NCMRA were also assessed. The image quality scores and contrast ratio (CR) of eight coronary artery segments from the four NCMRA sequences were quantitatively evaluated. Results The mean acquisition time of the conventional SENSE was 343 s, while that of CS4, CS5, and CS6 was 269, 215, and 190 s, respectively. The visible vessel length from the CS4 sequence showed good correlation and agreement with CCTA. The image quality score and CR from the CS4 sequence were not statistically significantly different from those in the other groups (p > 0.05). Moreover, the image score and CR showed a decreasing trend with the increase in the CS factor. Conclusions The CS technique could significantly shorten the acquisition time of NCMRA. The CS sequence with an acceleration factor of 4 was generally acceptable for NCMRA in clinical settings to balance the image quality and acquisition time.
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