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Letter to the Editor: Six-year prospective evaluation of second look US with volume navigation for MRI detected additional breast lesions.

by Erkin Aribal (earibal@gmail.com)

Six-year prospective evaluation of second-look US with volume navigation for MRI-detected additional breast lesions

We commend Fausto et al [1] for demonstrating the effectiveness of volume navigation technique (VNT) in finding MR only detected breast lesions after a negative second look US. We also used VNT in MR only detected lesions and showed its effectiveness as a guidance for a 14G core needle biopsy even in cases where a distinct lesion was not shown on US-VNT co-registered examination [2].

MR only detected breast lesions are challenging for breast radiologists as their detection with second look US varies. The authors claimed that 87,3% of the lesions that could not been detected by second look US can indeed be detected via the use of volume navigation technique (VNT). They used MRI guided biopsy for the remaining non-detected lesions (22 of 722 lesions) by either US methods [1]. Hence, volume navigation US examination stays as an effective tool for detection of MR only detected breast lesions. However, VNT necessitates a second contrast enhanced supine MR imaging. Furthermore, 12,7% of their patients did not benefit from VNT and had to undergo an MRI-guided biopsy with a third time contrast administration [1]. We have concerns in administering repetitive contrast agents in such a short period of time.

US-VNT can localize the lesion site with a very good precision and a 14G core needle biopsy with five passes can be performed in these cases even when the US-VNT cannot show any distinct lesion [2,3]. We believe that this method can reliably be performed as an alternate to MRI-guided biopsy which requires a third contrast administration. We wish to know if the authors ever tried to biopsy the corresponding lesion site in these patients with the guidance of VNT before the MRI guided intervention.

On the other hand, to avoid multiple contrast administrations, we are now adding a supplemental T1 weighted supine MRI sequence at the end of the primary standard prone dynamic contrast enhanced MRI (DCE-MRI) examination where the lesion is found. This supplemental supine T1 weighted image can be performed with placing the fiduciary markers on the breast which is needed for co-registration of the MR images with real time US. The duration of this supplemental supine MRI procedure takes no longer than 4 minutes (unpublished data). This examination allows to achieve the supine contrast enhanced MR data set for the co-registration of MRI with US without requiring a second contrast administration. We believe that this method can help to reduce the repetitive contrast media injections.