MRI-Guided Vacuum-Assisted Breast Biopsy Performed at 3 T With a 9-Gauge Needle: Preliminary Experience.
ABSTRACT OBJECTIVE: The purpose of this study was to test the feasibility of 3-T vacuum-assisted large-bore core biopsy of lesions detected with MRI of the breast. CONCLUSION: Our preliminary experience revealed that 3-T MRI-guided vacuum-assisted biopsy is a safe and effective interventional method that enables accurate biopsy of lesions identified with a 3-T MRI system. Artifacts on 3-T images did not result in failed biopsy; therefore, 3-T MRI systems can be used reliably for both diagnostic and interventional breast studies.
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ABSTRACT: 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.Magnetic resonance imaging clinics of North America 08/2013; 21(3):583-99.
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ABSTRACT: 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. 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. 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 1-100μT 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. 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.Medical Physics 05/2014; 41(5):052301. · 3.01 Impact Factor