Purpose: Cell size is a fundamental characteristic of all tissues, and changes in cell size in cancer reflect tumor status and response to treatments, such as apoptosis and cell-cycle arrest. Unfortunately, cell size can currently be obtained only by pathological evaluation of tumor tissue samples obtained invasively. Previous imaging approaches are limited to preclinical MRI scanners or require relatively long acquisition times that are impractical for clinical imaging. There is a need to develop cell-size imaging for clinical applications.
Methods: We propose a clinically feasible IMPULSED (imaging microstructural parameters using limited spectrally edited diffusion) approach that can characterize mean cell sizes in solid tumors. We report the use of a combination of pulse sequences, using different gradient waveforms implemented on clinical MRI scanners and analytical equations based on these waveforms to analyze diffusion-weighted MRI signals and derive specific microstructural parameters such as cell size. We also describe comprehensive validations of this approach using computer simulations, cell experiments in vitro, and animal experiments in vivo and demonstrate applications in preoperative breast cancer patients.
Results: With fast acquisitions (~7 minutes), IMPULSED can provide high-resolution (1.3 mm in-plane) mapping of mean cell size of human tumors in vivo on clinical 3T MRI scanners. All validations suggest that IMPULSED provides accurate and reliable measurements of mean cell size.
Conclusion: The proposed IMPULSED method can assess cell-size variations in tumors of breast cancer patients, which may have the potential to assess early response to neoadjuvant therapy.
Keywords: IMPULSED; MRI; OGSE; cell size; density; diameter; diffusion; oscillating gradient.
© 2019 International Society for Magnetic Resonance in Medicine.
In Vivo Imaging of Cancer Cell Size and Cellularity Using Temporal Diffusion SpectroscopyX Jiang et al. Magn Reson Med 78 (1), 156-164. PMID 27495144.The IMPULSED approach samples a specific region of temporal diffusion spectra with enhanced sensitivity to length scales of 10-20 μm, and enables measurements of cell siz …
Quantitative Temporal Diffusion Spectroscopy as an Early Imaging Biomarker of Radiation Therapeutic Response in Gliomas: A Preclinical Proof of ConceptX Jiang et al. Adv Radiat Oncol 4 (2), 367-376. PMID 31011683.This proof-of-concept study demonstrates the IMPULSED method to be a new method for deriving quantitative microstructural parameters in a preclinical tumor model. The met …
Feasibility of 7 Tesla Breast Magnetic Resonance Imaging Determination of Intrinsic Sensitivity and High-Resolution Magnetic Resonance Imaging, Diffusion-Weighted Imaging, and (1)H-magnetic Resonance Spectroscopy of Breast Cancer Patients Receiving Neoadjuvant TherapyMA Korteweg et al. Invest Radiol 46 (6), 370-6. PMID 21317792. - Clinical TrialDedicated 7T breast MRI is technically feasible, can provide more SNR than at 3T, and has diagnostic potential.
Microstructural Imaging of the Human Brain With a 'Super-Scanner': 10 Key Advantages of Ultra-Strong Gradients for Diffusion MRIDK Jones et al. Neuroimage 182, 8-38. PMID 29793061. - ReviewThe key component of a microstructural diffusion MRI 'super-scanner' is a dedicated high-strength gradient system that enables stronger diffusion weightings per unit time …
In Vivo Observations of Rapid Scattered Light Changes Associated With Neurophysiological ActivityDM Rector et al. PMID 26844322. - ReviewCognitive processes and other advanced neural functions rely on spatial and temporal interplay within linked neural networks. To study this interplay and test network lev …
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