Radio-guided occult lesion localisation for breast lesions under computer-aided MRI guidance: the first experience and initial results

Abstract

Objective: The purpose of this study was to present an alternative technique for the pre-operative localisation of solely MRI-detected suspicious breast lesions using a computer-assisted MRI-guided radio-guided occult lesion localisation (ROLL) technique.

Methods: Between January 2009 and June 2010, 25 females with a total of 25 suspicious breast lesions that could be detected only by MRI, and for whom breast surgery was planned, underwent the computer-assisted MRI-guided ROLL technique. A seven-channel biopsy breast array coil and computerised diagnostic workstation were used for the localisation procedure. Three-phase dynamic contrast-enhanced axial images were taken. After investigating the localisation co-ordinates with the help of intervention software on a workstation, an 18 G coaxial cannula was placed in the exact position determined. Following verification of the cannula position by additional axial scans, (99m)Tc-labelled macroalbumin aggregate and MRI contrast material were injected. Post-procedure MRI scans were used to confirm the correct localisation.

Results: All the procedures were technically successful. The mean lesion size was 10.8 mm (range: 4-25 mm). The mean total magnet and the mean localisation times were 28.6 min (range: 18-46 min) and 13.1 min (range: 8-20 min), respectively. Grid and pillar methods were used for localisation in 24 procedures and 1 procedure, respectively. On histopathological examination, 6 malignant, 10 high-risk and 9 benign lesions were identified. All patients tolerated the procedure well. There were no major complications.

Conclusion: This is the first report documenting the application of MRI-guided ROLL. Based on our preliminary results, this technique is very efficient and seems to be a good alternative to wire localisation.

Figure 1

Patient is positioned in a prone position and the left breast is immobilised with compression plates. Insertion of an 18 G cannula from the lateral approach is shown.

Figure 2

Pre-operative MRI-guided radio-guided occult lesion localisation in a 41-year-old patient with known contralateral invasive breast carcinoma. Axial localising images [repetition time (TR)/echo time (TE), 11/5.16; flip angle, 25°] show that the right breast is being compressed slightly. (a,b) The indentations of the grid lines are seen as small notches over the lateral aspect of the breast skin. (a) A 3 phase dynamic axial T₁ fast low-angle shot (FLASH) three-dimensional (3D) (TR/TE, 12/5.45, flip angle 25°) and (b) subtraction images show a 12 mm enhancing mass with fine contours (arrow). (c) Axial FLASH 3D images (TR/TE, 11/5.16, flip angle 25°) show an inserted cannula artefact as a hypointense line next to the lesion (arrowhead). (d) The T₁ FLASH 3D axial scan is taken after injection of the radionuclide and the contrast agent. The contrast agent accurately dyes the breast parenchyma in proximity to the lesion (arrow).

Figure 3

Pre-operative MRI-guided radio-guided occult lesion localisation (ROLL) in a 49-year-old patient with a suspicious lesion exhibiting spiculated contours and a washout enhancement pattern. There were also suspicious contrast enhancements, which indicated multicentricity. The most suspicious lesion with a spiculated contour was localised with ROLL. Histopathological examination revealed an invasive lobular carcinoma. (a) T₁ fast low-angle shot (FLASH) three-dimensional (3D) sagittal image shows two fiducial markers and grid compression marks on the lateral breast skin (arrows). (b) A contrast-enhanced axial subtraction image [T₁ FLASH 3D, repetition time (TR)/echo time (TE), 12/5.45; flip angle, 25°] indicates a spiculate-contoured enhanced 13 mm parenchymal mass lesion (arrow) together with other suspicious contrast enhancements (arrowheads). A thin hypointense cannula artefact appears 5 mm from the lesion (arrowhead). After advancing the cannula 5 mm, the ^99mTc-labelled macroalbumin aggregate in 0.2 ml saline and 1.5 ml of saline-diluted (1:200) MRI contrast agent is injected. (c) The derived axial T₁ FLASH 3D scan and (d) the subtraction image show (e) 2 cm of contrast-dyed parenchyma covering the spiculated lesion (arrowheads).