Technical note: Multi-receiver combination method for phase-based electrical property tomography of the breast

Abstract

Background: Phase-based electrical property tomography (EPT) is a technique that allows conductivity reconstruction with only phase of the B₁ field under the assumption that the magnitude of the B₁ fields are homogeneous. The more this assumption is violated, the less accurate the reconstructed conductivity. Thus, a method that ensures homogeneity of $|B_1^{-}|$ field is important for breast image using multi-receiver coil.

Purpose: To develop a method for multi-receiver combination for phase-based EPT usable for breast EPT imaging in the clinic.

Methods: Theory of the proposed method is presented. To validate the proposed method, the phantom and in-vivo experiments were conducted. Conductivity images were reconstructed using the transceive phase of the combined image and results were compared with another combination method.

Results: The proposed method's conductivity results were more stable than those of the previous method when $|B_1^{+}|$ was not homogeneous and when the homogeneous contrast region was small. The phantom and in-vivo results indicate that the proposed method produces improved conductivity images than the previous method. The proposed combination method also increased the conductivity contrast between benign and cancerous tissues.

Conclusion: The proposed method produced more stable multi-receiver combination for phase-based EPT of the breast in a clinical environment.

Keywords: breast conductivity; conductivity imaging; electrical properties tomography; multi-receiver combination; sensitivity estimation.