MRI-guided Biopsy Research Articles

Rectal Swabs for Detecting Multidrug Resistant Bacteria Prior to Transrectal Prostate Fusion Biopsy: A Prospective Evaluation of Risk Factor Screening and Microbiologic Findings

To assess the prevalence of fluoroquinolone resistant (QR) bacteria, multidrug resistant (MDR) bacteria and Enterococcus faecalis (E. faecalis) in rectal swabs of patients undergoing transrectal prostate biopsy and for evaluating if risk factor assessment is reliable for prediction of QR bacteria, MDR bacteria, or E. faecalis. Two hundred consecutive patients received a rectal swab examination prior to transrectal magnetic resonance imaging-guided fusion biopsy, for evaluating the prevalence of QR bacteria, MDR bacteria, and E. faecalis. The results of a standardized risk factor questionnaire, assessing known prognosticators for higher prevalence of resistant bacteria in rectal flora were correlated with the occurrence of QR bacteria, MDR bacteria, and E. faecalis in rectal swabs. QR E. coli was detected in 12 patients (6%). Regarding MDR bacteria, extended spectrum β- lactamase- producing E. coli occurred in 8 patients (4%). E. faecalis was found in 15 patients (7.5%). A total of 193 patients completed the risk factor questionnaire. Of those, 107 (53.2%) patients harbored no risk factors, while 86 (42.8%) had at least 1 risk factor, of which the most common was repeat biopsy. No association was found between any risk factor and occurrence of QR bacteria, MDR bacteria, or E. faecalis (P >.05). The prevalence of resistant germs in our cohort was lower compared to other series. Moreover, the rate of QR bacteria, MDR bacteria, or E. faecalis in rectal swabs was not reliably associated with risk factor assessment.

In-Bore MRI-guided Prostate Biopsies: Retrospective Observational Study of Complementary Nontargeted Sampling of Normal-appearing Areas at Multiparametric MRI.

To investigate the pathologic outcomes of additional random biopsies from areas with no visible MR targets in the setting of targeted in-bore MRI-guided biopsy and to assess the negative predictive value (NPV) of areas with no visible MR targets stratified according to patients' different biopsy statuses. A retrospective analysis of patients who underwent in-bore MRI-guided biopsy with additional random biopsies in areas with no visible MR targets (Prostate Imaging-Reporting and Data System, version 2 category 1 or 2) was conducted in this study. Diagnostic scans and in-bore MRI-guided biopsy were performed with a 3-T MRI scanner. Areas with no visible MR targets were biopsied in a random fashion whenever a zone or side did not have a visible focal target. Clinically significant cancers (CSCs) were defined as a Gleason score of 7 or greater. NPVs were stratified based on patient's prior biopsy status. Descriptive analysis was performed. A total of 59 consecutive patients were included, with a median age of 65 years (interquartile range [IQR], 59-71 years). The median prostate-specific antigen level was 7 ng/mL (IQR, 4.9-10.8 ng/mL). Of the 59 patients, 16 (27.1%) were biopsy naive, 24 (40.7%) had prior negative transrectal US-guided biopsy findings, and 19 (32.2%) had prior positive transrectal US-guided biopsy findings. Forty-two (71.2%) biopsies revealed prostate cancer. A total of 112 areas with no visible MR targets were biopsied, of which 20 (17.9%) were cancers and 11 (9.8%) were CSCs. The NPV of areas with no visible MR targets was approximately 78% for all cancers and was 88.1% for CSCs. NPVs in biopsy-naive patients, patients with prior negative transrectal US-guided biopsy findings, and patients with prior positive transrectal US-guided biopsy findings were 62.5%, 83.3%, and 84.2%, respectively, for all cancers and 75.0%, 91.7%, and 94.7%, respectively, for CSCs. Areas with no visible MR targets in patients with MR-suspicious foci may still harbor CSCs that may significantly affect management plans. Additional biopsies from areas with no visible MR targets are warranted in this population.Keywords: Biopsy/Needle Aspiration, Interventional-Body, MR-Imaging, Prostate, Urinary© RSNA, 2019.

Optimal Design of Bionic Flexible Fixation System for MRI-Guided Breast Biopsy

In Magnetic Resonance Imaging (MRI) guided intervention procedures, the flexibility and reliability of the mammary gland fixation device are important indicators for ensuring the quality of surgery. This paper presents a bionic flexible fixation system for MRI-guided breast biopsy, and establishes a mathematical model of the palm-type curved plate and a breast compression model. The bending angle, eccentricity, and tightening stroke of the palm-type curved plate are considered the main influencing factors. The bending angle and eccentricity of the bionic palm-type curved plate and flexible fingers are optimized, and a prototype of the breast fixation system is developed. The experimental results show that when the external force is 10 N, the average repetitive accuracy of four lesion points is 0.71 mm, 0.60 mm, 0.63 mm, and 0.68 mm, respectively. When the pressures are 8 N, 10 N, and 12 N, the thickness of the compressed tissue is 76.27 mm, 72.8 mm and 68.73 mm, respectively. It has good repetitive accuracy and is compatible with the concept of flexible fixation that reduces the uncomfortable feeling of the human body. We propose that by optimizing the flexible tightening mechanism, it is feasible to properly control the external compression force to effectively reduce the compression pain for patients while guaranteeing the tightening reliability in breast biopsy.

Dipole modeling of multispectral signal for detecting metallic biopsy markers during MRI-guided breast biopsy: a pilot study.

During MRI-guided breast biopsy, a metallic biopsy marker is deployed at the biopsy site to guide future interventions. Conventional MRI during biopsy cannot distinguish such markers from biopsy site air, and a post-biopsy mammogram is therefore performed to localize marker placement. The purpose of this pilot study is to develop dipole modeling of multispectral signal (DIMMS) as an MRI alternative to eliminate the cost, inefficiency, inconvenience, and ionizing radiation of a mammogram for biopsy marker localization. DIMMS detects and localizes the biopsy marker by fitting the measured multispectral imaging (MSI) signal to the MRI signal model and marker properties. MSI was performed on phantoms containing titanium biopsy markers and air to illustrate the clinical challenge that DIMMS addresses and on 20 patients undergoing MRI-guided breast biopsy to assess DIMMS feasibility for marker detection. DIMMS was compared to conventional MSI field map thresholding, using the post-procedure mammogram as the reference standard. Biopsy markers were detected and localized in 20 of 20 cases using MSI with automated DIMMS post-processing (using a threshold of 0.7) and in 18 of 20 cases using MSI field mapping (using a threshold of 0.65 kHz). MSI with DIMMS post-processing is a feasible technique for biopsy marker detection and localization during MRI-guided breast biopsy. With a 2-min MSI scan, DIMMS is a promising MRI alternative to the standard-of-care post-biopsy mammogram.

Increasing the diagnostic yield of stereotactic brain biopsy using intraoperative histological smear

ObjectiveThe negative biopsy rate approaches 5% in the literature. In our institution, this rate was 2.6% (42/1638) over a ten-year period (2007–2016). We aimed to assess the diagnostic yield of intraoperative smear during stereotactic biopsies to reduce this negative biopsy rate. Patients and methodsWe retrospectively analyzed all consecutive MRI-guided frame-based stereotactic biopsies for which an intraoperative histological smear was carried out, performed over 29 months from January 2017 to May 2019 at the Pitié-Salpêtrière University Hospital (Paris, France). Results145 stereotactic biopsies for which an intraoperative histological smear was carried out were performed in 145 adult patients. Mean age at biopsy was 52.4 ± 12.2 years. Histological diagnoses encountered in this series were: primary or secondary cerebral neoplasm (90.3%), inflammatory diseases (4.8%) and infectious diseases (4.8%). All biopsies were contributory to diagnosis. The negative biopsy rate was therefore significantly lower in the patient group for which an intraoperative histological smear was carried out than in our historical control group (0% versus 2.6%, p = 0.04). ConclusionConsidering the diagnostic yield benefit contributed by the intraoperative histological smear, we advocate for its routine use during brain stereotactic biopsies.

Association of Retrospective Peer Review and Positive Predictive Value of Magnetic Resonance Imaging-Guided Vacuum-Assisted Needle Biopsies of Breast.

To evaluate the association between retrospective peer review of breast magnetic resonance imaging-guided vacuum-assisted needle biopsies and positive predictive value of subsequent magnetic resonance imaging-guided biopsies. In January, 2015, a weekly conference was initiated in our institution to evaluate all breast magnetic resonance imaging-guided vacuum-assisted needle biopsies performed over January 1, 2014-December 31, 2015. During this weekly conferences, breast dynamic contrast-enhanced magnetic resonance imaging findings of 6 anonymized cases were discussed and then the faculty voted on whether they agree with the biopsy indication, accurate sampling and radiology-pathology correlation. We retrospectively reviewed and compared the magnetic resonance imaging indication, benign or malignant pathology rates, lesion types and the positive predictive value of magnetic resonance imaging-guided vacuum-assisted needle biopsy in the years before and after initiating this group peer review. The number of dynamic contrast-enhanced magnetic resonance imaging and magnetic resonance imaging-guided vacuum-assisted needle biopsies before and after initiating the review were 1447 vs 1596 (p=0.0002), and 253 (17.5%) vs 203 (12.7%) (p=0.04), respectively. There was a significant decrease in the number of benign biopsies in 2015 (n=104) compared to 2014 (n=154, p=0.04). The positive predictive value of magnetic resonance imaging-guided biopsy significantly increased after group review was implemented (Positive predictive value in 2014=%39.1 and positive predictive value in 2015=%48.8) (p=0.03), although the indications (p=0.49), history of breast cancer (p=0.14), biopsied magnetic resonance imaging lesion types (p=0.53) were not different. Less surgical excision was performed on magnetic resonance imaging-guided vacuum-assisted needle biopsy identified high-risk lesions in 2015 (p=0.25). Our study showed an association between retrospective peer review of past biopsies and increased positive predictive value of magnetic resonance imaging-guided vacuum-assisted needle biopsies in our institution.

A Testbed for Haptic and Magnetic Resonance Imaging-Guided Percutaneous Needle Biopsy

Magnetic resonance imaging (MRI) is used for soft tissue pathology diagnosis and assistance with targeted lesion procedures. However, limited physician access to patients in the magnetic resonance scanner bore requires iterative positioning and imaging, which extends the procedure time and increases patient risk. We present a teleoperated system and instrumented testbed for robotic MRI-guided needle biopsy, particularly targeting transperineal prostate biopsies. The device has a 1:1 kinematic mapping and uses a low-friction hydrostatic transmission based on antagonistic pairs of rolling diaphragms. It has three degrees of freedom (DOFs) and a passive two-DOF swivel, which holds a biopsy needle at the end-effector. Measured force hysteresis is 0.085 N (single DOF) and 0.44 N (full three-DOF manipulator) at the needle driving point. To quantitatively assess the system's haptic qualities, impulse modal testing for one DOF ( $>$ 300 Hz bandwidth) and three DOFs ( $>$ 40 Hz bandwidth) was conducted. Task performance was also assessed through membrane puncture testing with tissue phantoms; puncture events as low as 0.1 N are reliably detectable from transmission hydraulic pressure sensors.

Patient-Centered Outcomes From Multiparametric MRI and MRI-Guided Biopsy for Prostate Cancer: A Systematic Review.

ObjectiveTo identify and characterize patient-centered outcomes (PCOs) relating to multiparametric MRI (mpMRI) and MRI-guided biopsy as diagnostic tests for possible prostate cancer.MethodsMedline via OVID, EMBASE, PsycInfo, and the Cochrane Central register of Controlled Trials (CENTRAL) were searched for relevant articles. Hand searching of reference lists and snowballing techniques were performed. Studies of mpMRI and MRI-guided biopsy that measured any PCO were included. There were no restrictions placed on year of publication, language, or country for study inclusion. All database search hits were screened independently by two reviewers, and data were extracted using a standardized form.ResultsOverall, 2,762 database search hits were screened based on title and abstract. Of these, 222 full-text articles were assessed, and 10 studies met the inclusion criteria. There were 2,192 participants featured in the included studies, all of which were conducted in high-income countries. Nineteen different PCOs were measured, with a median of four PCOs per study (range 1-11). Urethral bleeding, pain, and urinary tract infection were the most common outcomes measured. In the four studies that compared mpMRI or MRI-guided biopsy to transrectal ultrasound biopsy, most adverse outcomes occurred less frequently in MRI-related tests. These four studies were assessed as having a low risk of bias.DiscussionPCOs measured in studies of mpMRI or MRI-guided biopsy thus far have mostly been physical outcomes, with some evidence that MRI tests are associated with less frequent adverse outcomes compared with transrectal ultrasound biopsy. There was very little evidence for the effect of mpMRI and MRI-guided biopsy on emotional, cognitive, social, or behavioral outcomes.

Prostate Cystadenocarcinoma: A Rare Cystic Epithelial Lesion in an Unusual Clinical Setting

Abstract Introduction Cystic tumors of prostate are rare and their clinicopathologic significance remains to be defined. The tumors present with either obstructive urinary symptoms or elevated serum prostate-specific antigen (PSA). Here we report a multilocular cystadenocarcinoma in a patient without significant urologic symptoms. Case Report A 71-year-old male with prior abnormal prostate biopsy, 6 years previously (unknown pathology), was referred for prekidney transplant workup. His symptom of oliguria and proteinuria was associated with end-stage renal disease without any obstructive urinary symptoms. Serum PSA detected 5.5 ng/mL. Magnetic resonance imaging (MRI) of the pelvis demonstrated a multilocular cystic lesion measuring 6.2 × 4.6 cm, arising from the right peripheral zone of prostate. The patient underwent MRI-guided prostate needle biopsy. Histology of prostate biopsy revealed glands and cystic structures lined by cuboidal to columnar epithelial cells with basally located hyperchromatic nuclei, pseudostratification, and focal papillary architecture. The cyst wall was immunoreactive for Cam 5.2, NKX 3.1, and AMACR, while negative for PAX8 and 34BE12 and p63, suggesting a diagnosis of primary prostate cystadenocarcinoma. The patient underwent robotic prostatectomy. The resected specimen showed a soft periprostatic mass, 6.8 × 5.0 cm at the right posterolateral aspect. Cut sections showed multiple multilocular cysts, with papillary projections, involving the right posterior-lateral surfaces with extensive extraprostatic extension. Histology showed multilocular cysts with papillary lining. Immunohistochemical studies showed strong reactivity of the cyst lining for NKX3.1, AMACR, weak CDX-2, and absent 34be12, p63, and ERG reactivity. The microscopic and immunohistochemical evidence supported a diagnosis of prostate cystadenocarcinoma, stage pT3a with free resection margin. Conclusion Cystadenocarcinoma is a variant of prostate carcinoma associated with obstructive urinary symptoms and potential for locally advanced growth. This case and other published reports of prostate cystadenocarcinoma show histologic features similar to the ductal variant of prostate adenocarcinoma, and therefore we suggest to grade it as Gleason pattern 4. The current case of prostate cystadenocarcinoma was an incidental diagnosis in an asymptomatic patient with mildly elevated PSA (T1c).

Magnetic Resonance Imaging–Guided Confirmatory Biopsy for Initiating Active Surveillance of Prostate Cancer

Transrectal, ultrasonography-guided prostate biopsy often fails to disclose the severity of underlying pathologic findings for prostate cancer. Magnetic resonance imaging (MRI)-guided biopsy may improve the characterization of prostate pathologic results, but few studies have examined its use for the decision to enter active surveillance. To evaluate whether confirmatory biopsy findings by MRI guidance are associated with the risk of pathologic disease upgrading among patients with prostate cancer during active surveillance. This retrospective cohort study used prospectively obtained registry data from 332 men with prostate cancer of Gleason grade group (GG) 2 or lower who were referred for active surveillance at a large academic medical center from January 1, 2009, through December 31, 2017. All confirmatory and follow-up biopsies were performed using MRI guidance with an MRI-ultrasonography fusion device. Patients underwent repeated MRI-guided biopsies every 12 to 24 months. At follow-up sessions, in addition to obtaining systematic samples, lesions seen on MRI were targeted and foci of low-grade prostate cancer were obtained again using tracking technology. Active surveillance was terminated with detection of at least GG3 disease or receipt of treatment. The primary outcome was upgrading to at least GG3 disease during active surveillance. Secondary outcomes were the associations of MRI lesion grade, prostate-specific antigen (PSA) level, PSA density, and biopsy method (targeted, systematic, or tracked) with the primary outcome. Of 332 patients (mean [SD] age, 62.8 [7.6] years), 39 (11.7%) upgraded to at least GG3 disease during follow-up. The incidence of upgrading was 7.9% (9 of 114) when the confirmatory biopsy finding was normal, 11.4% (20 of 175) when the finding showed GG1 disease, and 23.3% (10 of 43) when the finding was GG2 disease (P = .03). Men with GG2 disease were almost 8 times more likely to upgrade during surveillance compared with those with normal findings but only among those with low PSA density (hazard ratio [HR], 7.82; 95% CI, 2.29-26.68). A PSA density of at least 0.15 ng/mL/mL was associated with increased risk of upgrading among patients with normal findings (HR, 7.21; 95% CI, 1.98-26.24) or GG1 disease (HR, 2.86; 95% CI, 1.16 to 7.03) on confirmatory biopsy. A total of 46% of pathologic disease upgrades would have been missed if only the targeted biopsy was performed and 65% of disease upgrades were detected only with tracked biopsy. The findings suggest that confirmatory biopsy with MRI guidance is significantly associated with future disease upgrading of prostate cancer, especially when combined with PSA density, and should be considered as an appropriate entry point for active surveillance. Systematic and targeted biopsies were additive in detection of clinically significant cancers. Repeated biopsy at sites at which findings were previously abnormal (tracking biopsy) facilitated detection of cancers not suitable for continued active surveillance.

Screening vs staging magnetic resonance imaging-guided core needle breast biopsies: Does MRI indication impact upgrade rate?

Adjunct magnetic resonance imaging (MRI) for both screening high-risk patients and staging for patients with newly diagnosed breast cancer leads to an increased number of biopsies and increased detection of atypical lesions. We assessed whether the malignancy upgrade frequency for high-risk atypia identified via MRI-guided biopsies varied based on indication: high-risk screening vs staging for malignancy. Among 399 MRI-guided biopsies, 46 (11.5%) high-risk lesions (ADH, ALH, and LCIS) were identified. Surgical excision was performed on 37% of 46%, and 24.3% were upgraded to invasive malignancy or DCIS. Of lesions identified by staging MRI, a slightly higher percentage, 28.5%, were upgraded (P=.36). Our data suggest that surgeons should carefully consider excisional biopsy for atypia identified on MRI regardless of indication.

Apical periurethral transition zone lesions: MRI and histology findings.

Apical periurethral transition zone (TZ) cancers can pose unique problems for surgery and radiation therapy. Here, we describe the appearance of such cancers on multiparametric MRI (mpMRI) and correlate this with histopathology derived from MRI-targeted biopsy. Between May 2011 and January 2019, a total of 4381 consecutive patients underwent 3T mpMRI. Of these, 53 patients with 58 apical periurethral TZ lesions underwent TRUS/MRI fusion-guided biopsy and 12-core systematic TRUS-guided biopsy. Correlation was made with patient age, PSA, PSA density, whole prostate volume, and Gleason scores. A total 53 men (median age 68years, median PSA 7.94ng/ml) were identified as having at least one apical periurethral TZ lesion on mpMRI and 5 (9%) patients had more than one apical periurethral lesion. Thus, 58 lesions were identified in 53 patients. Of these 37/53 patients (69%) and 40/58 lesions were positive at biopsy for prostate cancer. Seven were diagnosed by 12-core systematic TRUS-guided biopsy and 34 were diagnosed by TRUS/MRI fusion-guided biopsy. Gleason score was ≥ 3 + 4 in 34/58 (58%) lesions. Identification of apical periurethral TZ prostate cancers is important to help guide surgical and radiation therapy as these tumors are adjacent to critical structures. Because of the tendency to undersample the periurethral zone during TRUS biopsy, MRI-guided biopsy is particularly helpful for detecting apical periurethral TZ prostate cancers many of which prove to be clinically significant.

Tissue marker migration after MRI-guided breast biopsy: Migration frequency and associated factors.

The purpose of this study was to determine the frequency and associated risk factors contributing to immediate tissue marker migration in patients undergoing MRI-guided breast biopsy and to evaluate how often tissue marker migration altered clinical management. Between July 2010 and May 2015, we retrospectively reviewed all MRI-guided breast biopsies at our institution for tissue marker migration. Migration was defined as final position of the tissue marker >10mm from the target site based on the expected location of the MRI finding on postprocedure mammogram. Factors associated with migration were analyzed using Fisher's exact test and Chi-squared test, with P<.05 considered statistically significant. A total of 278 patients underwent 298 MRI-guided biopsies. Migration occurred in 42/298 biopsies (14%). Almost entirely fat fibroglandular tissue was identified as an independent risk factor for tissue marker migration, occurring in 6/16 (38%), compared to 36/262 (14%) for the other fibroglandular tissue categories (P=.03). Biopsy target size was significantly associated with clip migration, occurring in 25/114 (22%) lesions <10mm in size vs 17/184 (9%) for larger lesions (P=.003). Clinical management was affected by clip migration in 6/42 cases (14%) with one requiring ultrasound-guided biopsy cavity marker placement and five requiring biopsy cavity wire localization. Radiologists must be vigilant in assessing for clip migration as it is not an infrequent complication. Given migration may change clinical management and require altered procedures for localization of the biopsy cavity, the possibility of clip migration should be included in informed consent.

Interobserver variability and likelihood of malignancy for fifth edition BI-RADS MRI descriptors in non-mass breast lesions

ObjectiveNon-mass enhancement (NME) in breast MRI is the most common feature of ductal carcinoma in situ (DCIS). We sought to evaluate the interobserver variability and positive predictive value (PPV) for malignancy of NME descriptors using the fifth edition BI-RADS lexicon focusing on the newly introduced “clustered ring enhancement” pattern.Materials and methodsBreast MRIs of 129 patients who had undergone MRI-guided vacuum-assisted biopsy (VAB) in our institution were reviewed. Studies assessed as NME were classified according to the fifth edition BI-RADS lexicon by two breast radiologists. Consensus was reached by involving a third radiologist. Interobserver variability and PPV for malignancy were assessed.ResultsSeventy-two of 129 studies were assessed as NME. The disagreement rate in the first assessment step (mass vs. NME) was low at 9.3% (ĸ = 0.81, 95% confidence interval [CI] 0.71–0.91). The disagreement rate for distribution patterns was 23.6% (ĸ = 0.67, 95% CI 0.54–0.80) and 22.2% (ĸ = 0.69, 95% CI 0.56–0.81) for internal enhancement patterns. Clustered ring enhancement (PPV 53.85, p = 0.038) and segmental distribution (PPV 62.5%, p = 0.028) had the highest malignancy rates among internal enhancement and distribution patterns with a significant result; the combination of clustered ring enhancement and segmental distribution raised the malignancy rate by approximately 4% (PPV 66.67%, p = 0.049).ConclusionThere was a high agreement rate among readers when differentiating NME from mass lesions. The agreement rate was lower when assessing the distribution and internal enhancement pattern descriptors, but still substantial. The descriptors clustered ring enhancement and segmental distribution were significant predictors of malignancy.Key Points• Non-mass enhancement is a common morphological feature of non-invasive breast cancer (DCIS) in MRI. Differentiation between potentially malignant and benign changes may be very challenging.• Since clustered ring enhancement and segmental distribution are both significant predictors of malignancy, the awareness of this important finding, combined with high-quality image interpretation skills, may improve the tumor detection rate.• The combination of clustered ring enhancement and segmental distribution increases the positive predictive value for malignancy, which may be relevant for clinical practice.

MRI-guided percutaneous needle biopsy with 1.2T open MRI: study protocol for a prospective feasibility study (SCIRO-1701).

ABSTRACTThere has been growing interest in magnetic resonance imaging (MRI)-guided interventional procedures such as percutaneous needle biopsy. Although open MRI is preferable for MRI-guided procedures in terms of patient accessibility, its inferior imaging capability due to lower field strength is a substantial limitation. In this situation, the high-field (1.2T) open MRI has recently become available. This novel MRI system is expected to provide excellent image quality as well as good patient accessibility, potentially contributing to safe and accurate device manipulation. This trial is designed to investigate the feasibility of MRI-guided percutaneous needle biopsy with this system. Patients with lesions needing percutaneous needle biopsy for pathological diagnosis are included. The enrollment of ten patients is intended. The primary endpoint of this study is the feasibility of biopsy needle insertion under real-time MR-fluoroscopy guidance based on the presence of the notch of the biopsy needle within the target lesion. The secondary endpoints are adverse events, device failures, and success of specimen acquisition. Once the feasibility of MRI-guided biopsy with 1.2T open MRI is validated by this study, it may potentially encourage widespread use of MRI-guidance for biopsy procedures. Furthermore, it may lead to development of the other MRI-guided interventional procedures using this MRI system.

In-Bore Transrectal MRI-Guided Biopsy With Robotic Assistance in the Diagnosis of Prostate Cancer: An Analysis of 57 Patients.

OBJECTIVE. The objective of our study was to analyze the feasibility and potential role of robotic-assisted transrectal MRI-guided biopsy for the diagnosis of prostate cancer. MATERIALS AND METHODS. A total of 57 patients (mean age, 67 ± 6 [SD] years; age range, 57-83 years; mean prostate-specific antigen level, 10.7 ± 6.1 ng/mL) with a single prostatic lesion visible on biparametric MRI (T2-weighted and DW images) underwent robotic-assisted MRI-guided transrectal biopsy. The procedure was analyzed in terms of technical success, defined by an accurate alignment of the needle guide with the lesion; occupation time of the MRI room; number of cores; cancer detection rate (CDR); and complications. RESULTS. The biparametric MRI score was 3, 4, and 5 in 11 (19%), 30 (53%), and 16 (28%) of the 57 patients, respectively. Twenty-three lesions (23/57, 40%) originated in the peripheral zone and 34 (34/57, 60%) in the transition zone. Software-based adjustments of the robot allowed the needle guide to be aligned with the target in all lesions. The number of cores was one, two, three, and four in one (2%), 36 (63%), 18 (32%), and three (5%) patients, respectively. Obtaining more than two cores had no incremental value in determining the Gleason score or the maximum cancer core length (MCCL). The overall CDR for any cancer was 67% (38/57). It was 95% (36/38) for tumors with Gleason grade of more than 3 or MCCL greater than 3 mm and 53% (20/38) for tumors with Gleason score greater than 6. No complications were observed. The median occupation time of the MRI room was 37.8 ± 9.7 minutes (range, 32-74 minutes). CONCLUSION. Robotic-assisted MRI-guided biopsy yields 100% technical success rate with a short MRI room occupation time and high CDRs using one or two cores.

MRI-guided frame-based stereotactic brainstem biopsy procedure: A single-center experience

Introduction and objectivesThis study aims at presenting our experience of the MRI-guided frame-based stereotactic brainstem biopsy method, and evaluating the outcomes of the procedure. Patients and methodsThe current study involved 18 cases that underwent MRI-guided frame-based stereotactic biopsy for brainstem lesions between 2011 and 2018 in our clinic. The relevant data regarding the technique of the biopsy procedure, morbidity, histopathological diagnosis it yields and diagnostic accuracy was retrospectively analyzed. ResultsStereotactic biopsy procedure was performed on 18 patients, including 16 adults and two children. MRI was used as guidance for the biopsy procedure in all patients. The adult patients had the biopsy under local anesthesia; as for the pediatric patients local anesthesia plus sedation was used. All patients received diagnosis based on the histopathological examination of their biopsy samples. No equivocal or negative results, and no major morbidity or mortality was seen in the patients after the procedure. ConclusionsMRI-guided frame-based stereotactic biopsy can be considered as a safe and efficient diagnostic method for brainstem lesions when its diagnostic yield and its morbidity and/or mortality rates are evaluated. Choosing the best trajectory for each lesion, using MRI as guidance for targeting, taking a limited number of biopsy samples are valuable criteria for the decreased morbidity rates in stereotactic brainstem biopsy procedures.

System Integration and Preliminary Clinical Evaluation of a Robotic System for MRI-Guided Transperineal Prostate Biopsy.

This paper presents the development, preclinical evaluation, and preliminary clinical study of a robotic system for targeted transperineal prostate biopsy under direct interventional magnetic resonance imaging (MRI) guidance. The clinically integrated robotic system is developed based on a modular design approach, comprised of surgical navigation application, robot control software, MRI robot controller hardware, and robotic needle placement manipulator. The system provides enabling technologies for MRI-guided procedures. It can be easily transported and setup for supporting the clinical workflow of interventional procedures, and the system is readily extensible and reconfigurable to other clinical applications. Preclinical evaluation of the system is performed with phantom studies in a 3 Tesla MRI scanner, rehearsing the proposed clinical workflow, and demonstrating an in-plane targeting error of 1.5mm. The robotic system has been approved by the institutional review board (IRB) for clinical trials. A preliminary clinical study is conducted with the patient consent, demonstrating the targeting errors at two biopsy target sites to be 4.0mm and 3.7mm, which is sufficient to target a clinically significant tumor foci. First-in-human trials to evaluate the system's effectiveness and accuracy for MR image-guide prostate biopsy are underway.

Open Source Platform for Transperineal In-Bore MRI-Guided Targeted Prostate Biopsy.

Accurate biopsy sampling of the suspected lesions is critical for the diagnosis and clinical management of prostate cancer. Transperineal in-bore MRI-guided prostate biopsy (tpMRgBx) is a targeted biopsy technique that was shown to be safe, efficient, and accurate. Our goal was to develop an open source software platform to support evaluation, refinement, and translation of this biopsy approach. We developed SliceTracker, a 3D Slicer extension to support tpMRgBx. We followed modular design of the implementation to enable customization of the interface and interchange of image segmentation and registration components to assess their effect on the processing time, precision, and accuracy of the biopsy needle placement. The platform and supporting documentation were developed to enable the use of software by an operator with minimal technical training to facilitate translation. Retrospective evaluation studied registration accuracy, effect of the prostate segmentation approach, and re-identification time of biopsy targets. Prospective evaluation focused on the total procedure time and biopsy targeting error (BTE). Evaluation utilized data from 73 retrospective and ten prospective tpMRgBx cases. Mean landmark registration error for retrospective evaluation was 1.88 ± 2.63 mm, and was not sensitive to the approach used for prostate gland segmentation. Prospectively, we observed target re-identification time of 4.60 ± 2.40 min and BTE of 2.40 ± 0.98 mm. SliceTracker is modular and extensible open source platform for supporting image processing aspects of the tpMRgBx procedure. It has been successfully utilized to support clinical research procedures at our site.

Do benign-concordant breast MRI biopsy results require short interval follow-up imaging? Report of longitudinal study and review of the literature

ObjectiveThe objectives of this study were to examine the frequency and outcomes of short interval imaging follow up of benign, concordant breast MRI biopsies and review the published literature on this topic. Materials and methodsThis was an IRB-approved, HIPAA compliant retrospective review of women undergoing MRI-guided breast biopsies between October 1, 2008 and December 31, 2014. Patients with malignant or high risk lesions with recommendation for excision, discordant cases, and those undergoing breast conservation therapy in same quadrant, chemotherapy or mastectomy were excluded. At least 2 years imaging and/or clinical follow-up without development of cancer in the same quadrant as the biopsy was set as the benchmark to confirm benign etiology. A PubMed search of similar articles through 2018 was also performed for the literature review. Results943 consecutive MRI-guided biopsies were performed in 785 women. Of these, 378/943 (40.1%) were benign and met inclusion criteria. Eleven cases were recommended for and underwent repeat MRI-guided biopsy or excision, 2 of which were malignant. The overall false negative rate for benign concordant MRI-guided biopsy was 2/378, 0.5% (95% CI 0.02 to 2.0%). Literature search demonstrated five articles with similar methodologies yielding 628 additional cases of benign concordant breast biopsies. Nine of these cases were eventually diagnosed as malignancy with a false negative rate of 1.4%. Combined with our data, the overall false negative rate is 1.1%. ConclusionsShort interval follow-up exams for benign concordant MRI-guided breast biopsies may not be necessary given the low malignancy rate.