MRI-guided vacuum-assisted breast biopsy performed at 3 T with a 9-gauge needle: preliminary experience

Small vascular lesions of the breast diagnosed by magnetic resonance imaging‐guided vacuum assisted biopsy: Report of 2 cases

Vascular lesions of the breast comprise a heterogeneous group that includes a variety of benign, atypical, and malignant lesions. These are a diagnostic challenge given variable clinical, radiological and pathological presentation, especially when they are small and asymptomatic. We present 2 cases of these rare lesions of the breast which were occult to mammographics and ultrasound studies. Both the lesions were detected only on magnetic resonance imaging, most helpful in the diagnosis of these rare tumor. Histopathological examinations following the magnetic resonance guided biopsies, were initially interpreted as negative for breast cancer in both cases. These turned out to be respectively a low grade angiosarcoma and a benign vascular lesion after a new histopathological examination following a larger magnetic resonance guided biopsies performed in light of the radiology-pathology discordance. Although rare, it is important to consider vascular tumours of the breast; radiologists need to be aware such tumors may present non-specific imaging features.

Minimal artifact actively shimmed metallic needles in MRI

PURPOSE

Signal voids caused by metallic needles pose visualization and monitoring challenges in many MRI applications. In this work, we explore a solution to this problem in the form of an active shim insert that fits inside a needle and corrects the field disturbance (ΔB₀ ) caused by the needle outside of it.

METHODS

The ΔB₀ induced by a 4 mm outside-diameter titanium needle at 3T is modeled and a two-coil orthogonal shim set is designed and fabricated to shim the ΔB₀ . Signal recovery around the needle is assessed in multiple orientations in a water phantom with four different pulse sequences. Phase stability around the needle is assessed in an ex-vivo porcine tissue dynamic gradient echo experiment with and without shimming. Additionally, heating of the shim insert is assessed under 8 min of continuous operation with 1A current and concurrent imaging.

RESULTS

An average recovery of ~63% of lost signal around the needle across orientations is shown with active shimming with a maximum current of 1.172 A. Signal recovery and correction of the underlying ΔB₀ is shown to be independent of imaging sequence. Needle-induced phase gradients outside the perceptible signal void are also minimized with active shimming. Temperature rise of up to 0.9° Celsius is noted over 8 min of continuous 1A active shimming operation.

CONCLUSION

A sequence independent method for minimization of metallic needle induced signal loss using an active shim insert is presented. The method has potential benefits in a range of qualitative and quantitative interventional MRI applications.

Primary Extranodal Follicular T-Cell Lymphoma and Ductal Breast Carcinoma Diagnosed by a Magnetic Resonance Imaging-Guided Vacuum-Assisted Biopsy: A Case Report

BACKGROUND Extranodal non-Hodgkin lymphomas (NHL) are low-grade B-cell lymphomas and the breast is not a common site for this condition. This case report describes a 62-year-old woman with a primary NHL and ductal carcinoma in situ (DCIS) of the left breast diagnosed by a magnetic resonance imaging (MRI)-guided vacuum-assisted breast biopsy. The simultaneous diagnosis of breast cancer and NHL is rare, with few cases described in the literature. Primary breast lymphomas account only for 0.04% to 0.5% of breast malignancies. CASE REPORT In November 2016, a 62-year-old woman was treated for a peripheral T-cell lymphoma (follicular helper T-cell phenotype) of the left upper central breast; later she underwent periodic breast imaging follow-ups. In October 2018, MRI revealed a focal 33-mm non-mass contrast enhancement (according to the Breast Imaging Reporting and Data System -MRI lexicon of the American College of Radiology) in the lower external quadrant of the left breast. Neither mammography nor ultrasonography demonstrated any suspicious features. The multidisciplinary medical team performed an MRI-guided vacuum-assisted breast biopsy and the histological analysis confirmed the diagnosis of a DCIS. Subsequently, she underwent surgery resulting in eradication of the disease and has had regular follow-ups, including mammography, ultrasonography, and MRI. CONCLUSIONS This is a rare case of both a primary NHL of the breast and DCIS, which was detected only by MRI. It highlights the role of an MRI-guided vacuum-assisted breast biopsy, which allows an accurate and economic diagnosis in case of suspicious findings on MRI. We recommend the use of MRI in follow-ups for patients with previous breast lymphomas (high-risk patients).

MR imaging-guided vacuum assisted breast biopsy: Radiological-pathological correlation and underestimation rate in pre-surgical assessment

BACKGROUND

Magnetic Resonance(MR) guided percutaneous procedures(MRgVABB) have been developed and largely employed to reduce the need of surgical biopsies for suspicious lesions which can be detected only by MR(MR-only lesion). The present study aims to investigate correlation between imaging, histological features of MRgVABB and surgical specimens of MR-only lesions.

METHODS

We retrospectively enrolled 56 patients with a total of 61 lesions. Each finding was defined as Mass-Enhancement(ME) or Non-ME(NME) and classified according to BI-RADS. MRgVABB and surgical data were collected. Concordance between MR, MRgVABB and open biopsy was calculated. Underestimation Rate(UR) of MRgVABB with surgery was obtained.

RESULTS

B2 and B5b lesions were statistically associated with NME and ME, respectively. No statistical association was found to B3 nor to B5a with radiological features. UR was 10 %; underestimated lesions were strongly associated with the presence of a ME on MR imaging. Moreover, B3 lesions are associated with higher UR.

CONCLUSION

Radiological features should influence patient management aiming to construct a correct diagnostic and therapeutic plan. When MR is prescribed for breast cancer staging for ME-MR-only lesions, we suggest surgical open biopsy instead of MRgVABB when upfront surgery is the treatment of choice.

Modeling of active shimming of metallic needles for interventional MRI

PURPOSE

Artifacts caused by large magnetic susceptibility differences between metallic needles and tissue are a persistent problem in many interventional MRI applications. The signal void caused by the needle can hide procedure targets and prevent accurate image-based monitoring. In this paper, a solution to this problem is presented in the form of an active shim insert inspired from degaussing coils used in naval vessels, that is designed to correct the field disturbance (ΔB₀ ) caused by the needle.

METHODS

The ΔB₀ induced by a 10 gauge hollow single-beveled titanium needle at 3T is modeled in different orientations. A set of 63 orthogonal coil pairs with unique tip paths are evaluated for shimming performance, and an optimal coil pair is chosen. Shimming performance and current demands are evaluated over a range of needle orientations.

RESULTS

Robust correction of the titanium needle induced ΔB₀ is predicted using a flat no-loop coil combined with an orthogonal 1½ turn loop coil angled at the bevel angle for most orientations, with currents well below 1 amp per coil. Reductions in ΔB₀ standard deviations with shimming ranged from ~49% to ~10% depending on needle orientation, with performance worsening as the needle is aligned more along B₀ .

CONCLUSION

Simulations predict that it is possible to minimize metallic probe induced ΔB₀ and signal losses using externally supplied direct current shim coil inserts in arbitrary orientations for potential benefits in many interventional MRI applications.

Freehand 3T MR-guided vacuum-assisted breast biopsy (VAB): a five-year experience

Background Magnetic resonance (MR) permits the detection of some malignant lesions that cannot be identified with mammography or ultrasonography. The characterization of these MR-only detectable lesions often requires a biopsy. Purpose To evaluate the technique, the feasibility and the accuracy of freehand 3T MR-guided VAB for the characterization of suspicious, MR-only detectable lesions and to compare VAB results with surgical pathology and follow-up imaging results. Material and Methods During 2010-2015, 118 women who were referred for MR-guided VAB were retrospectively reviewed. All BI-RADS MR 4 and 5 lesions and some BI-RADS MR 3 lesions (according to clinical context and patient anxiety) were scheduled to undergo biopsy. Results A total of 123 suspicious lesions were retrospectively selected. Technical failures occurred in only two cases (1.6%) due to the location of the lesions. Histopathological results revealed 59 benign lesions (48%), 27 high-risk lesions (22%), and 35 malignant lesions (28.4%). Surgical pathology results led to the reclassification of eight B3 lesions: one proved to be a ductal carcinoma in situ, while seven presented with invasive features. B3 underestimation also occurred in 29% of the cases. MR follow-up was achieved for all the benign lesions and no false-negative cases were observed. No complications, 3T-related artefacts, or difficulties were observed. Conclusion Freehand 3T MR-guided VAB was found to be a valid, safe, fast, and inexpensive alternative to surgical histology.

MR Imaging-Guided Breast Interventions: Indications, Key Principles, and Imaging-Pathology Correlation

MR imaging is now routinely performed for breast cancer screening and staging. For suspicious MR imaging-detected lesions that are mammographically and sonographically occult, MR imaging-guided breast interventions, including biopsy, clip placement, and preoperative needle localization, have been developed to permit accurate tissue diagnosis and aid in surgical planning. These procedures are safe, accurate, and effective when performed according to key principles, including proper patient selection, use of appropriate technique, adequate preprocedure preparation and postprocedure patient care, and postprocedure imaging-pathology correlation. Imaging-pathology correlation after MR imaging-guided biopsy is essential to confirm accurate sampling and guide development of a comprehensive management plan.

Imaging-Concordant Benign MRI-Guided Vacuum-Assisted Breast Biopsy May Not Warrant MRI Follow-Up

OBJECTIVE

The follow-up of breast lesions with imaging-concordant benign histopathology results on MRI-guided vacuum-assisted biopsy (VAB) is not currently standardized. We determined the false omission rate of breast MRI-guided VAB with benign histopathology (negative results) to assess whether breast MRI follow-up is needed.

MATERIALS AND METHODS

The medical records of patients who underwent 9-gauge breast MRI-guided VAB during 2007-2012 were reviewed retrospectively. Lesions with imaging-concordant benign histopathology results from MRI-guided VAB and surgery or 2 years or more of imaging follow-up were included. The false omission rate (1 - negative predictive value; [number of false-negative results / number of negative results]) of MRI-guided VAB was calculated.

RESULTS

One hundred sixty-nine lesions were included, and 135 had only imaging follow-up (mammography follow-up: range, 17-107 months [median, 52 months]; MRI follow-up: range, 5-95 months [median, 35 months]). Of the 135 lesions with only imaging follow-up, 48 had mammography only (range, 26-86 months; median, 52 months), and 87 had mammography (range, 17-107 months; median, 52 months) and MRI (range, 5-95 months; median, 35 months). Thirty-four lesions had surgical correlation, and there were no cases of imaging-surgical discordance. Four malignancies were later diagnosed in the same breast in which MRI-guided VAB had been performed. One (0.6%) malignancy was invasive ductal carcinoma at 1 cm from the MRI-guided VAB site; it was mammographically detected 24 months after MRI-guided VAB. The other three malignancies developed 4 cm or more from the site of MRI-guided VAB: one ductal carcinoma in situ (DCIS) detected on mammography 12 months after MRI-guided VAB, one DCIS detected on MRI 24 months after MRI-guided VAB, and one Paget disease lesion detected at physical examination 32 months after MRI-guided VAB.

CONCLUSION

Breast MRI-guided VAB has a low false omission rate. MRI follow-up of lesions with concordant benign MRI-guided VAB histopathology results may not be warranted.

An image-guided automated robot for MRI breast biopsy

BACKGROUND

The IGAR (Image-guided Automated Robot) is a robotic platform capable of performing highly accurate clinical interventions under image guidance. The IGAR is unique in that it demonstrates MRI compatibility and maintains safe operation, adequate shielding, high image quality, and accurate robotic control even while in an imaging environment. The IGAR is initially intended for breast biopsy.

METHODS

Tests for projectile hazards, heating, signal-to-noise ratio loss, and geometric distortion were used to demonstrate MR compatibility. Accuracy and repeatability of the robotic system were tested on benchtop models to establish a baseline of precision.

RESULTS

The IGAR averaged an accuracy of 0.34 mm and a repeatability of 0.2 mm. There was no significant distortion attributable to the robot, no projectile risk, and no unacceptable levels of heating.

CONCLUSION

The IGAR system is safe and effective in an MRI environment Copyright © 2016 John Wiley & Sons, Ltd.

The effects of magnetic field distortion on the accuracy of passive device localization frames in MR imaging

PURPOSE

The interventional magnetic resonance (MR) imaging environment presents many challenges for the accurate localization of interventional devices. In particular, geometric distortion of the static magnetic field may be both appreciable and unpredictable. This paper aims to quantify the sensitivity of localization error of various passive device localization frames to static magnetic field distortion in MR.

METHODS

Three localization frames were considered based on having distinctly different methods of encoding position and orientation in MR images. For each frame, the effects of static field distortion were modeled, allowing rotational and translational errors to be computed as functions of the level of distortion, which was modeled using a first order approximation. Validation of the model was performed by imaging the localization frames in a 3T clinical MR scanner, and simulating the effects of static field distortion by varying the scanner's center frequency and gradient shim values.

RESULTS

Plots of the rotational and translational components of error in localization frame position and orientation estimates are provided for ranges of uniform static field distortions of 1-100 μT and static field distortion gradients of 0.01-1 mT/m in all three directions. The theoretical estimates are in good agreement with the results obtained by imaging.

CONCLUSIONS

The error in position and orientation estimation of passive localization frames in MR can be sensitive to static magnetic field distortions. The level of sensitivity, the type of error (i.e., rotational or translational), and the direction of error are dependent on the frame's design and the method used to image it. If 2D gradient echo imaging is employed, frames with position and orientation estimate sensitivity to slice-select error (such as the z-frame) should be avoided, since this source of error is not easily correctable. Accurate frame position and orientation estimates that are insensitive to static field distortion can be achieved using 2D gradient echo imaging if: (a) the method of determining position and orientation only uses in-plane measurements of marker positions, (b) the in-plane marker positions in images are not sensitive to slice-select error, and (c) methods of correcting in-plane error in the frequency-encoded direction are employed.

Radiologic-pathologic correlation at breast MR imaging: what is the appropriate management for high-risk lesions?

Breast magnetic resonance (MR) imaging is increasingly performed for a variety of indications, most commonly with the goal of detecting breast cancer. Percutaneous biopsy (usually under MR guidance or ultrasound if there is a correlating finding) is commonly used to evaluate suspicious imaging findings detected on MR imaging with the goal of identifying malignancy. It is important to be familiar with the characteristics and management of high-risk lesions detected or biopsied under MR guidance. This review focuses on the appearance of a variety of breast lesions detected on MR imaging that require excision with focus on pathologic correlation.