Magnetic resonance imaging-guided core needle biopsy and needle localized excision of occult breast lesions

MRI-guided needle localization: Indications, tips, tricks, and review of the literature

We describe the history of, indications for, and techniques involved in MRI-guided needle localization (MRI-NL). MRI-NL continues to be a safe, effective method of sampling lesions that are only detected with MRI, particularly for anatomically challenging lesions such as those near the chest wall, the nipple, the skin, and/or in close proximity to implants.

MRI vacuum-assisted breast biopsies

The indications, technique, results and limitations of MRI vacuum-assisted breast biopsies are discussed from a review of the literature. This was initially a home-grown technique and its development was slowed down by several factors. As a result of major technical advances, it has become a reliable and very consistent procedure with a low rate of underestimation. It is now an undisputed technique when suspicious MRI enhancement is seen with no corresponding mammography or ultrasound features.

Impact of clinical and lesion characteristics on the results of MR-guided wire localizations of the breast using an open 1.0-T MRI system

PURPOSE

Preoperative magnetic resonance (MR)-guided wire localizations are warranted in patients with suspicious focal breast lesions on MR mammographic findings without equivalent in x-ray mammography and ultrasonography. The study was performed to assess the impact of clinical parameters, tumor size, and target localization on the procedural characteristics in magnetic resonance imaging (MRI)-guided wire localizations of breast lesions using an open 1.0-T open MR system.

MATERIAL AND METHODS

The clinical, radiological, and histological characteristics of all 347 patients and all 394 interventional procedures performed in a 6-year interval were extracted from the clinical files. Two board-certified senior radiologists evaluated the impact of target localization and the size on the interventional results in the available 302 image data sets. Patient characteristics, lesion characteristics, and interventional results were statistically correlated in subgroup analyses.

RESULTS

A total of 387 of the 394 MR-guided wire localizations (98.2%) were technically successful. In 7 cases (2.3%), the intervention was aborted because the suspicious finding of the diagnostic MR mammography could not be visualized during the intervention. Minor complications occurred in 13 interventions (3.3%). The histological workup of the operative specimen showed benign results in 226 of the 394 interventions (57.4%) and malignant findings in 154 wire localizations (39.1%). The mean (SD) length of the interventional procedure time defined as the time interval between the start of the first and of the last MRI sequence as documented in the electronic MRI data sets was 24.6 (8.4) minutes. Patient age, medical history, and the anticipated risk for developing breast cancer and a simultaneous known carcinoma did not affect the technical success and complication rates and the interventional procedure time. A total of 60 targets (19.5%) were located in the retromamillary zone, 89 targets (28.9%) in the peripheral zone, and 1 target (0.3%) near the chest wall. The maximum diameter was 1 to 5 mm in 64 lesions (21.2%), 6 to 10 mm in 136 lesions (45.0%), 11 to 15 mm in 56 lesions (18.6%), and 16 mm or greater in 46 lesions (15.2%). A total of 23 of the 100 histologically proven invasive carcinomas had a maximum MRI diameter of 1 to 5 mm (23.0%) and 38 (38.0%) of 6 to 10 mm.

CONCLUSIONS

Magnetic resonance-guided wire localizations of suspicious breast lesions using an open high-field MR system are a clinically safe and feasible method even in small target lesions and anatomical regions that are usually considered difficult to access.

Feasibility of MRI-guided large-core-needle biopsy of suspiscious breast lesions at 3 T

The feasibility of large-core-needle magnetic resonance imaging (MRI)-guided breast biopsy at 3 T was assessed. Thirty-one suspicious breast lesions shown only by MRI were detected in 30 patients. Biopsy procedures were performed in a closed-bore 3-T clinical MR system on a dedicated phased-array breast coil with a commercially available add-on stereotactic biopsy device. Tissue sampling was technically successful in 29/31 (94%) lesions. Median lesion size (n = 29) was 9 mm. Histopathological analysis showed 19 benign lesions (66%) and one inconclusive biopsy result (3%). At follow-up of these lesions, 15 lesions showed no malignancy, no information was available in three patients and two lesions turned out to be malignant (one lesion at surgical excision 1 month after biopsy and one lesion at a second biopsy because of a more malignant enhancement curve at 12-months follow-up MRI). Nine biopsy results showed a malignant lesion (31%) which were all surgically removed. No complications occurred. MRI-guided biopsy at 3 T is a safe and effective method for breast biopsy in lesions that are occult on mammography and ultrasound. Follow-up MRI at 6 months after the biopsy should be performed in case of a benign biopsy result.

Magnetic resonance imaging--guided breast interventions

The use of breast magnetic resonance imaging (MRI) for screening, diagnosis, staging, and management of breast cancer is rapidly increasing. MRI is highly sensitive for the detection of benign and malignant abnormalities that are occult to physical examination, ultrasound, and mammography. However, the specificity of MRI is moderate. These attributes necessitate methods for MR-guided tissue sampling to determine the histology of MRI detected lesions. This article will review appropriate peer-reviewed data and currently accepted methods for MR-guided tissue sampling. A detailed step-by-step technique for vacuum-assisted MR-guided breast biopsy is included. We also review emerging data for percutaneous and transcutaneous MR-guided breast interventions such as tissue ablation for benign and malignant disease.

Breast-conserving surgery using projection and reproduction techniques of surgical-position breast MRI in patients with ductal carcinoma in situ of the breast

BACKGROUND

In this study, we report a breast-conserving surgery (BCS) approach that uses projection and reproduction techniques of breast MRI obtained in the surgical position to the breast surface in patients with ductal carcinoma in situ (DCIS) of the breast.

STUDY DESIGN

Between February 2005 and January 2007, a total of 104 patients with operable breast cancer at our hospital had surgical-position breast MRI examinations. The 24 patients with relatively localized DCIS received BCS using the projection and reproduction techniques of the surgical-position breast MRI. During the same time period, 28 patients with relatively localized DCIS in whom prone-position breast MRI was performed, had conventional BCS using mammography-guided hookwires. In this study, we compared the surgical outcomes of our surgical approach with those of the conventional approach in a total of 52 patients with relatively localized DCIS.

RESULTS

Average volume of the pathologic specimens in the new technique group (27.5 cm(3)) was substantially smaller than that in the conventional BCS group (57.6 cm(3), p = 0.0007). In addition, the positive margin rate was substantially lower in the new technique group (12.5%) than in the conventional BCS group (39.3%; p = 0.029).

CONCLUSIONS

This study demonstrates that BCS can be done guided by the precise projection and reproduction techniques of the lesion obtained by surgical-position breast MRI. To the best of our knowledge, this is the first report of BCS technique for DCIS in this manner. Our surgical approach can be clinically useful in surgical planning and management in patients with DCIS.

MRI-directed, wire-localized breast excisions: incidence of malignancy and recommendations for pathologic evaluation

Magnetic resonance imaging (MRI) has an evolving role in the evaluation of breast lesions and is currently being used for the screening of high-risk patients (eg, women with a personal or family history of breast cancer), for the evaluation of extent of disease in patients with a current diagnosis of cancer, and for patients with suspicious, but indeterminate, findings by other imaging modalities. If a suspicious lesion detected by MRI is not well visualized by another method, an MRI-directed core biopsy or breast excision may be performed. MRI cannot be used to verify the lesion in the specimen because MRI lesion detection is dependent on uptake of gadolinium after intravenous injection. Accordingly, these breast excisions present unique challenges to pathologists. The purpose of this report is to define the surgical pathology issues involved in processing MRI-localized excisions. Retrospective review of 85 consecutive MRI-directed breast excisions from 77 patients was performed. Malignant lesions were present in 20 (24%) of 85 excisions, including 10 cases of invasive carcinoma (median size, 0.4 cm), 9 cases of ductal carcinoma in situ, and 1 case of lymphoma. Most of the malignancies (85% or 17/20) had no associated gross finding and only 5 (25%) of 20 of these malignancies were associated with a definite finding on the specimen radiograph. This study demonstrates that gross examination and specimen radiography do not identify most of the malignancies in MRI-localized biopsies and, therefore, optimal processing requires complete microscopic examination of these specimens.

MRI-Guided Breast Interventions

The use of breast magnetic resonance imaging (MRI) in the diagnosis, staging, and management of breast cancer is rapidly increasing. MRI has the ability to detect malignancy that is occult to physical exam, ultrasound, and mammography. These qualities necessitate methods for MRI-guided tissue sampling. This article reviews all previously published and currently accepted methods for MRI-guided tissue sampling. The data to support these techniques are provided where appropriate. A detailed technique for vacuum-assisted breast biopsy is included. We will also review the data on other MRI-guided breast interventions such as transcutaneous tissue ablation.

MRI-guided needle localization of suspicious breast lesions: results of a freehand technique

Magnetic resonance imaging (MRI) can detect clinically and mammographically occult breast lesions. In this study we report the results of MRI-guided needle localization of suspicious breast lesions by using a freehand technique. Preoperative MRI-guided single-needle localization was performed in 220 patients with 304 MRI-only breast lesions at our hospital between January 1997 and July 2004. Procedures were performed in an open 0.5-T Signa-SP imager allowing real-time monitoring, with patient in prone position, by using a dedicated breast coil. MRI-compatible hookwires were placed in a noncompressed breast by using a freehand technique. MRI findings were correlated with pathology and follow-up. MRI-guided needle localization was performed for a single lesion in 150 patients, for two lesions in 56 patients, and for three lesions in 14 patients. Histopathologic analysis of these 304 lesions showed 104 (34%) malignant lesions, 51 (17%) high-risk lesions, and 149 (49%) benign lesions. The overall lesion size ranged from 2.0-65.0 mm (mean 11.2 mm). No direct complications occurred. Follow-up MRI in 54 patients showed that two (3.7%) lesions were missed by surgical biopsy. MRI-guided freehand needle localization is accurate and allows localization of lesions anterior in the breast, the axillary region, and near the chest wall.

A case of occult contralateral breast cancer incidentally detected by contrast-enhanced MRI; report of a case with review of literature

We encountered a case of occult contralateral breast cancer, previously undetected by conventional imaging such as mammography (MMG) and ultrasonography (US), but incidentally detected by contrast-enhanced magnetic resonance imaging (CE-MRI). We present it here with a review of the literature. A 67-year-old Japanese woman was referred to our hospital in October 2000 because of a 1.5 cm right breast lump detected in a medical checkup. MMG, US and fine needle aspiration cytology revealed a cancerous lesion during the right breast. No mass lesion was palpable nor was any detected by MMG or US in the left breast. Bilateral breast CE-MRI was performed for more detailed evaluation. Consequently, an occult contralateral breast cancerous lesion was detected incidentally by CE-MRI, with the images showing rapid initial enhancement of time to signal intensity curves. Before surgery, bilateral breast lesions were diagnosed as invasive ductal carcinoma by open biopsy. She underwent bilateral breast conserving surgery with bilateral axillary lymph node dissection. The postoperative course was uneventful and no recurrence has been noted as of January 18th, 2004. CE-MRI of the contralateral breast should be of value as a routine screen in those patients with a known or suspected malignancy in one breast considering the limits of breast cancer detection by such conventional modalities as MMG and US.

Contrast-enhanced MRI in breast cancer patients eligible for breast-conserving therapy: complementary value for subgroups of patients

The aim of this study was to identify patients prior to breast-conserving therapy (BCT) who have complementary value of contrast-enhanced magnetic resonance imaging (MRI) over conventional imaging in the assessment of tumor extent. All patients were eligible for BCT according to conventional imaging, and underwent preoperative MRI as part of this study. One hundred and sixty-five patients (166 tumors) were included. MRI was defined to have complementary value if conventional imaging underestimated or overestimated tumor extent (by more than 10 mm compared to histology) and MRI assessed the extent accurately. Logistic regression was employed to identify characteristics that are predictive of the complementary value of preoperative MRI. MRI had complementary value in 39 cases (23%). Patients <58 years old with irregular lesion margins at mammography and discrepancy in tumor extent by more than 10 mm between mammography and ultrasonography had a 3.2x higher chance of accurate assessment at MRI (positive predictive value 50%, negative predictive value 84%, p=0.0002). Preoperative MRI in patients eligible for BCT is more accurate than conventional imaging in the assessment of tumor extent in approximately one out of four patients. Subgroups of patients in whom MRI has complementary value may be defined by the differences in clinical and imaging features.

MR-Guided Interventions of the Breast

Techniques and instrumentation are now widely available that enable interventional MR-guided preoperative needle localization and lesion marking. Minimally invasive MR-guided core biopsy techniques have been demonstrated but remain limited for small lesions and will be facilitated by the development of biopsy instruments that can be directly visualized using MR imaging. MR-guided tumor ablation is beginning to be evaluated in a few centers. It holds promise as new treatment modality in the continuing trend toward greater breast conservation in the local therapy of breast cancer. Further studies are needed to document the ability of MR-guided ablation to control the margins of a tumor as effectively as surgery. Patients with an extensive in situ intra-ductal component may pose a significant hurdle because the extent of ductal carcinoma in situ maybe underestimated on breast MR images. Ultimately, the success of MR-guided thermal ablation depends on the ability of MR imaging to map the extent of heating during the procedure so that the procedure can be performed to achieve complete control of the tumor margins. It is unfortunate that the conventional method for MR thermometry--the proton resonance frequency shift method--does not work in fat or in voxels with a mix of fat and glandular tissue and, hence, has limited applicability in the breast. Other methods, including measurement of T1 and T2, are being investigated as alternatives.

Clinical Experience with MRI-Guided Vacuum-Assisted Breast Biopsy

OBJECTIVE

The objective of our study was to evaluate a new commercially available method of MRI-guided vacuum-assisted breast biopsy using an open coil and a closed 1.5-T scanner.

MATERIALS AND METHODS

Consecutive MRI-guided vacuum-assisted breast biopsies of 38 lesions in 28 women performed between May and September 2003 at two practice sites in the United States were retrospectively reviewed. Lesion characteristics including size, morphology, and enhancement were recorded. Times to perform each procedure, defined as the time from the start of the first localizing scan to the final scan after biopsy, were recorded. Histologic results for all lesions were obtained, and surgical, imaging, or clinical follow-up was performed.

RESULTS

Enhancing masses and foci ranged from 2.5 to 19 mm. Nonmasslike enhancements ranged from 6 to 70 mm. All 38 biopsies (100%) were technically successful, and no complications were associated with any of the biopsy procedures. The average time to perform the 19 single-site MRI-guided procedures was 38 min (range, 23-57 min). The 11 multiple-site biopsies performed in a single breast averaged 59 min (range, 51-68 min), and eight bilateral biopsies averaged 64 min (range, 46-80 min). Histologic results from vacuum-assisted breast biopsy revealed malignancy in 14 lesions (37%), atypical ductal hyperplasia in two lesions (5%), and benign findings in 22 lesions (58%). One of two lesions with atypical ductal hyperplasia was upgraded to ductal carcinoma in situ after surgery, for an overall cancer yield of 40% (15/38).

CONCLUSION

This new method of MRI-guided vacuum-assisted breast biopsy is a safe, effective, and time-efficient means of MRI-guided tissue sampling.

Clinically and mammographically occult breast lesions on MR images: potential effect of computerized assessment on clinical reading

PURPOSE

To investigate if and how computerized analysis complements characterization of breast lesions with clinical reading at magnetic resonance imaging.

MATERIALS AND METHODS

The institutional review board approved the use of data obtained prospectively and analyzed either prospectively with informed patient consent or retrospectively with waiver of consent. An existing computerized analysis system was retrained with 100 breast lesions (in 78 patients with mean age of 46.5 years) and tested with 136 other lesions (in 113 patients with mean age of 48.9 years; P=.15 for age difference between groups). Seventy-five lesions in the training set were previously rated by one of three radiologists in daily clinical practice. Lesion rating (as benign, probably benign, indeterminate, suspicious, or highly suggestive of malignancy) and probability of malignancy calculated with computerized analysis were included as covariates in logistic regression analysis to obtain a combined model. The performance of the model was compared with that of clinical reading alone in a set of 72 clinically and mammographically occult lesions not used to train the computerized analysis system (in 60 patients with mean age of 43.5 years; P=.09 for age difference between training and testing groups). Receiver operating characteristic (ROC) curves were plotted, and areas under the ROC curves were calculated and compared.

RESULTS

Performance of reading in the clinical setting, as indicated by area under the ROC curve (Az=0.86), was similar to that of computerized analysis (Az=0.85; P=.99). Significant overall improvement in performance was obtained with the combined model (Az=0.91; P=.03). Improvement was accomplished mostly in characterization of lesions rated indeterminate or suspicious by radiologists.

CONCLUSION

Computerized analysis complements clinical reading and makes computer-aided diagnosis feasible. The complementary information has the potential to increase overall performance for clinically and mammographically occult lesions.

An MRI-compatible semiautomated vacuum-assisted breast biopsy system: Initial feasibility study

PURPOSE

To develop an MR-compatible vacuum-assisted core needle breast biopsy system.

MATERIALS AND METHODS

A vacuum-assisted breast biopsy system (Mammotome Hand Held; Ethicon Endo-Surgery, USA) was modified for freehand MRI-guided biopsy in an open, interventional 0.5-T scanner (Signa SP; GE, USA). Probes (11 gauge [G]) were fabricated without significant susceptibility artifact. These mate with an electromechanical hand piece and control system that were modified for use within the MRI scanner. A total of 62 breast lesions were simulated in the mammary tissues of six recently lactating sows by injecting between 0.1 and 1.0 mL of an aqueous gel containing dilute gadopentetate dimeglumine (Gd-DTPA) that formed a bright mass on T1-weighted imaging.

RESULTS

Mechanical performance was satisfactory. Magnetic susceptibility and radiofrequency (RF) artifacts from the 11-G probe were negligible. T1-weighted fast spin echo (FSE) was used to guide biopsy. Up to eight samples were removed per lesion. Overall, 461 samples were obtained in 493 attempts (94%). Sample weights averaged 54 mg (N = 493) compared to 4.6 mg (N = 24) from 14-G titanium MRI-compatible needles. On average, 59% of the attempted samples yielded target lesion material.

CONCLUSION

Preliminary results demonstrate the feasibility of a vacuum-assisted breast biopsy system in the MRI environment. Small 0.1-mL lesions can be biopsied without needle artifacts obscuring the target.

Ultrasound in the Changing Approaches to Breast Cancer Diagnosis and Treatment

Advances in ultrasound technology have not only refined this modality for diagnostic purposes, but have also extended its utility to the realm of treatment. Specific patient populations benefit from the addition of ultrasound to mammographic screening, such as those with BRCA-1 or BRCA-2 mutations or a personal or family history of breast cancer. Ultrasound is of particular benefit in guiding wire localization under sedation, as well as in guiding core biopsies and fine-needle aspirations. Current ablative techniques, including radiofrequency, cryoablation and laser, are now incorporating ultrasound guidance to maximize efficacy. Furthermore, ultrasound has been found to have significant utility in guiding preablative core biopsies for definitive diagnosis, estrogen receptor (ER)/progesterone receptor (PR), HER-2/neu, and other markers. As a result of its proven utility, ultrasound is now undergoing evaluation for use in the removal of malignant breast lesions.

Minimally invasive surgery for small breast cancer

BACKGROUND AND METHODS

So-called minimally invasive techniques make percutaneous eradication of breast tumors possible, thus leading to breast-conserving treatment (BCT) without surgery. This paper reviews and discusses the feasibility of minimally invasive techniques for breast cancer.

RESULTS

Although a wide variety of ablation techniques have been investigated for the treatment of primary breast cancer, radiofrequency ablation (RFA) remains one of the most promising and potentially useful tools. RFA therapy results in effective cell killing in a predictable volume of tissue with a low complication rate. On the other hand, ultrasonography is useful for guiding the needle within the tumor but cannot predict the extent of thermal ablation accurately. Early post-procedural magnetic resonance imaging (MRI) may be useful for assessing whether complete tumor ablation has been achieved by RFA. Whether adequate ablation of the tumor has been achieved can be confirmed by extensive core needle sampling of the treated area. However, validation of the margin status is also important and this needs to be tackled in further studies.

CONCLUSIONS

There are many problems that remain before RFA therapy can be considered for conventional treatment. Further studies are needed to determine whether the use of RFA alone for local treatment of primary breast cancer will result in local recurrence and survival rates equivalent to those seen with BCT.

A manipulator system for 14-gauge large core breast biopsies inside a high-field whole-body MR scanner

PURPOSE

To investigate a robotic manipulator system for MR-guided breast biopsies inside a 1.5 T whole-body magnet.

MATERIALS AND METHODS

Fourteen patients with suspicious breast lesions (diameter 18.6 +/- 12 mm) underwent biopsy. Patients with malignant findings underwent surgery afterwards and the histologic findings between biopsy and surgery were correlated.

RESULTS

In five patients biopsy findings were histopathologically confirmed following open surgery. One tubular carcinoma was missed; one invasive cancer was underestimated. Seven patients with benign findings are still in the follow-up period.

CONCLUSION

The study demonstrates the feasibility to perform breast biopsies inside the magnet of a whole-body MR scanner by using a manipulator system.

Advances in the Diagnosis and Excision of Breast Cancer

Until recently little advance in the diagnosis and excision of breast cancer has been made since the inception of needle localization breast biopsy (NLBB). Stereotactic core needle breast biopsy (SCNBB) can avoid most NLBB especially for calcifications. However, when open biopsy is necessary NLBB has been the standard of care. As many as 50 per cent of nonpalpable lesions can be seen by ultrasound (US) to avoid the unpleasantness and complications associated with NLBB. Further SCNBB leaves a blood-filled cavity that can be easily seen by US. Intraoperative US can be used to direct the excision while improving margin negativity. MRI has improved sensitivity in detecting suspicious breast lesions and techniques such as hematoma-directed US-guided breast biopsy can facilitate excision of such masses. Clearly new technologies have improved the ability to diagnosis and excise breast cancer. The onus on the surgeon is to incorporate them into standard practice to improve outcomes.