The authors evaluated a magnetic resonance (MR) imaging-compatible biopsy device comprising a needle guide that can be visualized with MR imaging and manipulated mechanically from outside the MR unit. With approval from the local ethics committee and patient consent, this device was tested in 12 patients by using a closed 1.5-T MR unit and a body phased-array coil. Patients had elevated prostate-specific antigen levels (6-60 ng/mL) and one or more areas in the prostate that were suspicious for carcinoma at prebiopsy MR imaging. Biopsy was performed with transrectal access and with the patient prone. A 16-gauge MR imaging-compatible needle was successfully positioned with the device, and between six and nine tissue cores were obtained in each patient. In one patient, two suspicious basal areas could not be reached with the device. Histologic analysis showed prostate cancer in five patients and prostatitis in six. No complications were observed. The device enabled MR imaging-guided core-needle biopsy of prostate areas suspicious for cancer on MR images.
Thirty-seven consecutive patients with elevated PSA levels and negative tumor prostate biopsies underwent a MR-guided prostate biopsy in a 1.5-T scanner in the supine position. After localization of suspected tumor areas using an endorectal coil and two body-phased array coils, the biopsy device was positioned without any repositioning of the patient. The biopsy device consisted of a mount, a ball joint, a positioning stage and an insertion stage with a needle guide, which was filled with a MR-visible fluid to control positioning of the needle using a balanced steady-state free precession sequence (TrueFISP) and a high-resolution turbo spin echo (T2-TSE) sequence. Core biopsies were taken manually in the magnet. The biopsy needle could be correctly positioned in all cases. Suspected lesions with a diameter > or =10 mm could be successfully punctured. Four to nine (mean = 6) biopsies were taken per patient. In 14 patients, prostate cancer was confirmed at histology. Twenty-four biopsies positive for cancer were performed in 14 patients. A correct correlation was found between the site of biopsy and histology. MR-guided prostate biopsy can be effective in increasing primary positive tumor biopsy results in patients with a history of negative tumor TRUS-guided prostate biopsies.
Purpose:To evaluate the advantages of using an active marker (active micro coil) for MR-guided breast biopsy procedures.
Materials and Methods:An add-on breast biopsy guidance device used with a standard breast coil was equipped with an active marker. The marker's position was determined with a dedicated MRI sequence. In combination with custom software, the biopsy planning process was reduced basically to defining the target in the diagnostic MR images. Automatic control scans verified the settings of the biopsy guidance device. To measure the targeting accuracy, x-ray control of the needle placement was performed in phantoms containing 36 small titanium cylinders. The reliability of the procedure was evaluated in 24 core needle biopsies on phantoms. Workflow enhancements were analyzed.
Results:The root mean square deviation of the needle position from the target perpendicular to the needle axis was 1.25 mm, in three-dimensions it was 1.35 mm. All targets were sampled successfully. The duration of a phantom biopsy was nine minutes.
Conclusion:The use of an active marker can offer advantages for MR-guided breast biopsies in terms of handling and procedure time as well as accuracy.
In spite of slightly restricted image quality, the described drilling machine combined with the bone biopsy set is well suited for MR-guided bone biopsies, which require the application of a motor driven drill. Its application within an interventional MR scanner is safe and its handling simple and manageable.
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