Effect of Radiofrequency Transmit Field Correction on Quantitative Dynamic Contrast-enhanced MR Imaging of the Breast at 3.0 T
Bedir Abdel Rasoul, Reem
Effect of B1+ field correction on Quantitative Dynamic contrast enhanced MRI of the breast at 3.0T
Radiological Society of North America
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Bedir Abdel Rasoul, R., Graves, M., Patterson, A., McLean, M., Manavaki, R., Wallace, T., Reid, S., et al. (2015). Effect of Radiofrequency Transmit Field Correction on Quantitative Dynamic Contrast-enhanced MR Imaging of the Breast at 3.0 T. Radiology https://doi.org/10.1148/radiol.2015150920
Purpose: To investigate the effects of radiofrequency transmit field (B₁⁺) correction on (a) the measured T1 relaxation times of normal breast tissue and malignant lesions and (b) the pharmacokinetically derived parameters of malignant breast lesions at 3 T. Materials and Methods: Ethics approval and informed consent were obtained. Between May 2013 and January 2014, 30 women (median age, 58 years; range, 32–83 years) with invasive ductal carcinoma of at least 10 mm were recruited to undergo dynamic contrast material–enhanced magnetic resonance (MR) imaging before surgery. B₁⁺ and T1 mapping sequences were performed to determine the effect of B₁⁺ correction on the native tissue relaxation time (T1₀) of fat, parenchyma, and malignant lesions in both breasts. Pharmacokinetic parameters were calculated before and after correction for B₁⁺ variations. Results were correlated with histologic grade by using the Kruskal-Wallis test. Results: Measurements showed a mean 37% flip angle difference between the right and left breast, which resulted in a 61% T1₀ difference in fat and a 41.5% difference in parenchyma between the two breasts. The T1 of lesions in the right breast increased by 58%, whereas that of lesions in the left breast decreased by 30% after B₁⁺ correction. The whole-tumor transendothelial permeability across the vascular compartment(Kᵗʳᵃⁿˢ) of lesions in the right breast decreased by 41%, and that of lesions in the left breast increased by 46% after correction. A systematic increase in Kᵗʳᵃⁿˢ was observed, with significant differences found across the histologic grades (P < .001). The effect size of B₁⁺ correction on Kᵗʳᵃⁿˢ calculation was large for lesions in the right breast and moderate for lesions in the left breast (Cohen effect size, d = 0.86 and d = 0.59, respectively). Conclusion: B₁⁺ correction demonstrates a substantial effect on the results of quantitative dynamic contrast-enhanced analysis of breast tissue at 3 T, which propagates into the pharmacokinetic analysis of tumors that is dependent on whether the tumor is located in the right or left breast.
The project was supported by the Addenbrooke’s Charitable Trust and the NIHR comprehensive Biomedical Research Centre (BRC) and the Experimental Cancer Medicine Centre (ECMC) awards to Cambridge University Hospitals NHS Foundation Trust in partnership with the University of Cambridge.
Cancer Research UK (unknown)
Cambridge University Hospitals NHS Foundation Trust (CUH) (3819/1415/ 19)
Cancer Research UK (C14303/A17197)
Cambridge University Hospitals NHS Foundation Trust (CUH) (unknown)
External DOI: https://doi.org/10.1148/radiol.2015150920
This record's URL: https://www.repository.cam.ac.uk/handle/1810/249037