Breast Tissue Expanders with Magnetic Ports: Clinical Experience at 1.5 T

Abstract

Background: The purpose of this study was to evaluate breast tissue expanders with magnetic ports for safety in patients undergoing abdominal/pelvic magnetic resonance angiography before autologous breast reconstruction. Methods: Magnetic resonance angiography of the abdomen and pelvis at 1.5 T was performed in 71 patients in prone position with tissue expanders with magnetic ports labeled “MR Unsafe” from July of 2012 to May of 2014. Patients were monitored during magnetic resonance angiography for tissue expander–related symptoms, and the chest wall tissue adjacent to the tissue expander was examined for injury at the time of tissue expander removal for breast reconstruction. Retrospective review of these patients’ clinical records was performed. T2-weighted fast spin echo, steady-state free precession and gadolinium-enhanced spoiled gradient echo sequences were assessed for image artifacts. Results: No patient had tissue expander or magnetic port migration during the magnetic resonance examination and none reported pain during scanning. On tissue expander removal (71 patients, 112 implants), the surgeons reported no evidence of tissue damage, and there were no operative complications at those sites of breast reconstruction. Conclusion: Magnetic resonance angiography of the abdomen and pelvis in patients with certain breast tissue expanders containing magnetic ports can be performed safely at 1.5 T for pre–autologous flap breast reconstruction perforator vessel mapping. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Dislodgement of tissue expander ports in a patient without trauma or MRI history

“… 5 , 6 , 7 , 8 Of note, in a study of 71 patients with tissue expanders who received abdominal and pelvic magnetic resonance angiography (MRA) at 1.5 Tesla, no patient had magnetic port migration, indicating that adjustments made during magnetic resonance imaging can make this exam safer. 9 …”

Reconsidering the “MR Unsafe” breast tissue expander with magnetic infusion port: A case report and literature review

“…In contrast, several higher level-of-evidence studies indicated that patients with TEs with magnetic ports can be scanned safely using MRI: Nava et al [3] found that TEs demonstrated minimal heating and had minor attraction to a 1.5 T static magnetic field and Marano et al [4] similarly found minimal heating and low magnetic field interactions in three TEs tested under 1.5 and 3 T MRI conditions. Furthermore, in a retrospective case series involving 71 patients with 112 TEs, Thimmappa et al [5] reported that abdominal MRA yielded no reports of magnetic port migration or pain. Subsequent surgeon examination of the peri-TE space during autologous breast reconstruction revealed “no evidence of tissue damage, and there were no operative complications at those sites of breast reconstruction.” This group’s experience has further increased to more than 250 patients without substantial complications (personal communication, Martin R. Prince, M.D., Ph.D., Radiology, Weill Cornell Medical Center, NY, 11/01/18).…”

“…In conclusion, despite a careful, systematic review, the controversies regarding the safety of a TE with a magnetic port in the MRI setting remain unanswered. Of note is that, during a period of more than three decades, only two cases reported problems associated with TE exposure to MRI [10,11], while a study conducted in a large series of patients where special precautions were taken to mitigate risks revealed no substantial issues [5].…”

“…The majority of implant-based breast reconstructions utilize tissue expanders (TEs) in the first stage of reconstruction [1]. Because the magnetic infusion ports incorporated into most TEs presumably interact adversely with the electromagnetic fields used for magnetic resonance imaging (MRI), all such TEs are labeled "MR Unsafe" [2][3][4][5]. Therefore, the consensus practice is to use other imaging techniques when diagnostic exams are needed for patient management, such as ultrasound or computed tomography [3][4][5].…”

Modern techniques and alternative flaps in microsurgical breast reconstruction

“…Some patients may also have a contraindication to the use of magnetic resonance (MR) in general. This was thought to include patients with breast tissue expanders, which has since been proven not to be the case …”