MR-guided biopsy of suspect breast lesions with a simple stereotaxic add-on-device for surface coils

Current status of MRI-guided vacuum-assisted breast biopsy in Japan

In April 2018, the national health insurance coverage of MRI-guided vacuum-assisted breast biopsy (VAB) was instituted with the application of the Japan Breast Cancer Society. Although MRI-guided VAB has been considered as a special procedure for a long time, having an access to this procedure should be recommended for facilities performing breast MRI as in Western countries. From now on, relevant societies should make efforts in data collection and quality control of MRI-guided VAB in Japan. We must avoid the following. To delay the early diagnosis of breast cancer in the judgment of an inaccurate indication, perform unnecessary biopsy due to overestimation of diagnosis, and reduce the success rate of MRI-guided VAB with immature techniques. This review explains the current status of MRI-guided VAB in Japan and shares procedure and biopsy data as a future reference from an experienced facility.

CT-guided percutaneous needle placement in forensic medicine

We have developed a technique of CT-guided needle placement in the destructed human body in forensic practice. A sixty-year-old male was found in a burned car and he was also destructed severely. Although blood was needed for the external examination, it was difficult to approach the vessels because of the severely burned condition of the cadaver. Thus, we attempted to obtain a blood sample from a vessel using a CT-guided technique. Postmortem CT demonstrated the presence of blood-containing vessels in the pelvis. Indeed, CT-guided needle placement had no difficulty with surface markers, table location, or depth measurement from the surface. CT-guide needle placement is a feasible and reliable technique, so that when the tissue/blood sample is at risk of being spoiled, CT-guided needle placement could be a substitute for conventional sampling techniques.

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.

Gd-labeled glycol chitosan as a pH-responsive magnetic resonance imaging agent for detecting acidic tumor microenvironments

Neoplastic lesions can create a hostile tumor microenvironment with low extracellular pH. It is commonly believed that these conditions can contribute to tumor progression as well as resistance to therapy. We report the development and characterization of a pH-responsive magnetic resonance imaging contrast agent for imaging the acidic tumor microenvironment. The preparation included the conjugation of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid 1-(2,5-dioxo-1-pyrrolidinyl) ester (DOTA-NHS) to the surface of a water-soluble glycol chitosan (GC) polymer, which contains pH-titrable primary amines, followed by gadolinium complexation (GC-NH2-GdDOTA). GC-NH2-GdDOTA had a chelate-to-polymer ratio of approximately1:24 and a molar relaxivity of 9.1 mM(-1) s(-1). GC-NH2-GdDOTA demonstrated pH-dependent cellular association in vitro compared to the control. It also generated a 2.4-fold enhancement in signal in tumor-bearing mice 2 h postinjection. These findings suggest that glycol chitosan coupled with contrast agents can provide important diagnostic information about the tumor microenvironment.

MRI-guided intervention for breast lesions using the freehand technique in a 3.0-T closed-bore MRI scanner: feasibility and initial results

Objective

To report the feasibility of magnetic resonance imaging (MRI)-guided intervention for diagnosing suspicious breast lesions detectable by MRI only, using the freehand technique with a 3.0-T closed-bore MRI scanner.

Materials and Methods

Five women with 5 consecutive MRI-only breast lesions underwent MRI-guided intervention: 3 underwent MRI-guided needle localization and 2, MRI-guided vacuum-assisted biopsy. The interventions were performed in a 3.0-T closed-bore MRI system using a dedicated phased-array breast coil with the patients in the prone position; the freehand technique was used. Technical success and histopathologic outcome were analyzed.

Results

MRI showed that four lesions were masses (mean size, 11.5 mm; range, 7-18 mm); and 1, a nonmass-like enhancement (maximum diameter, 21 mm). The locations of the lesions with respect to the breast with index cancer were as follows: different quadrant, same breast - 3 cases; same quadrant, same breast - 1 case; and contralateral breast - 1 case. Histopathologic evaluation of the lesions treated with needle localization disclosed perilobular hemangioma, fibrocystic change, and fibroadenomatous change. The lesions treated with vacuum-assisted biopsy demonstrated a radial scar and atypical apocrine hyperplasia. Follow-up MRI after 2-7 months (mean, 4.6 months) confirmed complete lesion removal in all cases.

Conclusion

MRI-guided intervention for breast lesions using the freehand technique with a 3.0-T closed-bore MRI scanner is feasible and accurate for diagnosing MRI-only lesions.

Radio-guided occult lesion localisation for breast lesions under computer-aided MRI guidance: the first experience and initial results

OBJECTIVE

The purpose of this study was to present an alternative technique for the pre-operative localisation of solely MRI-detected suspicious breast lesions using a computer-assisted MRI-guided radio-guided occult lesion localisation (ROLL) technique.

METHODS

Between January 2009 and June 2010, 25 females with a total of 25 suspicious breast lesions that could be detected only by MRI, and for whom breast surgery was planned, underwent the computer-assisted MRI-guided ROLL technique. A seven-channel biopsy breast array coil and computerised diagnostic workstation were used for the localisation procedure. Three-phase dynamic contrast-enhanced axial images were taken. After investigating the localisation co-ordinates with the help of intervention software on a workstation, an 18 G coaxial cannula was placed in the exact position determined. Following verification of the cannula position by additional axial scans, (99m)Tc-labelled macroalbumin aggregate and MRI contrast material were injected. Post-procedure MRI scans were used to confirm the correct localisation.

RESULTS

All the procedures were technically successful. The mean lesion size was 10.8 mm (range: 4-25 mm). The mean total magnet and the mean localisation times were 28.6 min (range: 18-46 min) and 13.1 min (range: 8-20 min), respectively. Grid and pillar methods were used for localisation in 24 procedures and 1 procedure, respectively. On histopathological examination, 6 malignant, 10 high-risk and 9 benign lesions were identified. All patients tolerated the procedure well. There were no major complications.

CONCLUSION

This is the first report documenting the application of MRI-guided ROLL. Based on our preliminary results, this technique is very efficient and seems to be a good alternative to wire localisation.

MRI-guided breast biopsy: influence of choice of vacuum biopsy system on the mode of biopsy of MRI-only suspicious breast lesions

OBJECTIVE

The purpose of this study was to evaluate two systems of MRI-guided vacuum-assisted biopsy and to investigate the influence of the choice of system on the choice of biopsy mode in the care of patients with lesions found only at MRI.

MATERIALS AND METHODS

Over a period of 3 years, a total 349 patients underwent MRI-guided tissue sampling of 475 lesions found only at MRI. The lesions were sampled by needle localization plus excisional biopsy or by vacuum-assisted biopsy. Two different systems were used for MRI-guided vacuum-assisted biopsy. During the first half of the study period, a handheld system was used, and during the second half, a console system was used. The procedural advantages and disadvantages, size of lesions biopsied, and time needed for vacuum-assisted biopsy were recorded. The distribution of the type of intervention (needle localization or vacuum-assisted biopsy) used to manage MRI-only lesions during the two study periods also was assessed.

RESULTS

The average diameter of lesions sampled with vacuum-assisted biopsy was 19.2 mm with the handheld system and 10.4 mm with the console system (p < 0.039). The average biopsy time was 69 minutes for the handheld system and 39 minutes for the console system (p < 0.005). Of the total of 170 MRI-only lesions biopsied with the handheld system, 121 (71%) were sampled by localization and 49 (29%) by vacuum-assisted biopsy. Of the total 305 MRI-only lesions biopsied with the console system, 38 (12%) were sampled by localization and 267 (88%) by vacuum-assisted biopsy.

CONCLUSION

Because of the procedural advantages of use of the console-based system, smaller lesions were biopsied in less time and with higher operator confidence. This result translated into a major shift in the care of patients with MRI-only lesions away from lesion localization toward increased use of MRI-guided vacuum-assisted biopsy.

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.

Recent advances and current controversies in the management of DCIS of the breast

Ductal carcinoma in situ (DCIS) is commonly diagnosed today, mainly due to widespread use of screening mammography. Despite a better understanding of its biological behavior, many issues regarding its optimal management remain controversial. The biological behavior of DCIS has been associated with distinct molecular and histological features (such as expression of COX2, Ki67, c-erbB2, p53 mutation, presence or absence of comedonecrosis, nuclear grade, hormone receptor status, etc.). Recent advances in the diagnosis of DCIS include using magnetic resonance imaging, and the use of stereotactic-guided directional vacuum-assisted biopsy (DVAB). Ductoscopy and ductal lavage have a limited role in the management of DCIS. Surgical treatment of DCIS includes simple local excision to various forms of wider excision (segmental resection or quadrantectomy), or even mastectomy (either simple or skin-sparing). Radiotherapy following breast-conserving surgery significantly reduces local recurrence rates. Axillary lymph node dissection is not required for the management of DCIS; however, during the last decade, sentinel lymph node biopsy is increasingly used to exclude the presence of axillary metastases (when invasive disease is present within the DCIS). This approach has many advantages (including the avoidance of a second surgery if invasive disease is diagnosed within the DCIS) and should be considered when there is an increased probability for the presence of invasive breast cancer within the DCIS. The role of other minimally invasive methods (such as the "therapeutic" application of the DVAB technique, radiofrequency ablation, laser therapy, cryotherapy and brachytherapy) in the management of small DCIS remains unproven. Tamoxifen should be considered in the management of selected patients with DCIS, such as patients with hormone receptor positive DCIS, young patients, and patients without risk factors for potential side effects. Additionally, and controversial, there is evidence that aromatase inhibitors may be better than tamoxifen in the management of DCIS.

The current status of breast MR imaging. Part I. Choice of technique, image interpretation, diagnostic accuracy, and transfer to clinical practice

Compared with mammography and breast ultrasonography, contrast material-enhanced magnetic resonance (MR) imaging is a breast imaging technique that offers not only information on lesion cross-sectional morphology but also on functional lesion features such as tissue perfusion and enhancement kinetics. After an enthusiastic start to clinical breast MR imaging in the early 1990s, a variety of difficulties and obstacles were identified that hampered the transfer of the modality into clinical practice, including a lack of standardization regarding image acquisition and interpretation guidelines, a lack of MR-compatible interventional materials, and a lack of evidence regarding its diagnostic accuracy--particularly specificity and positive predictive value, as well as sensitivity for ductal carcinoma in situ. This article is the first of two on the current status of breast MR imaging. The pathophysiologic basis of breast MR and the effects on acquisition technique and diagnostic accuracy, the diverging demands of high spatial and temporal resolution, and the different approaches that exist for image acquisition are reviewed. Advantages and disadvantages of different pulse sequence parameters are discussed to help radiologists make a balanced and informed decision regarding choice of image acquisition protocol. Imaging findings in common benign and malignant changes are described, and current concepts for differential diagnosis, including the MR Breast Imaging Reporting and Data System lexicon, are discussed. Furthermore, obstacles that impeded the technique's transfer into clinical practice are discussed, and the progress made in recent years, especially regarding the development of guidelines, procedural standardization, and MR-guided interventions are outlined.

Computer assistance for MR based diagnosis of breast cancer: present and future challenges

MR based methods have gained an important role for the clinical detection and diagnosis of breast cancer. Dynamic contrast-enhanced MRI of the breast has become a robust and successful method, especially for diagnosis of high-risk cases due to its higher sensitivity compared to X-ray mammography. The application of MR based imaging methods depends on various automated image processing routines. The combination of techniques for preprocessing, quantification and visualization of datasets is necessary to achieve fast and solid assessment of valuable parameters for diagnosis. In this paper, different aspects such as registration methods for the reduction of motion artifacts, segmentation issues, as well as morphologic and dynamic lesion analysis will be reviewed with a focus on breast MRI, MR spectroscopy and MR guided biopsies of the breast, their implications and technical challenges from a computer assistance point of view.

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.

MR Imaging–guided 9-gauge Vacuum-assisted Core-Needle Breast Biopsy: Initial Experience

PURPOSE

To perform magnetic resonance (MR) imaging-compatible vacuum-assisted 9-gauge core-needle biopsy of suspicious enhancing breast lesions identified at MR imaging.

MATERIALS AND METHODS

The institutional review board granted exempt status for this HIPAA-compliant study and waived the requirement for informed consent. The MR imaging-guided 9-gauge vacuum-assisted core-needle biopsy findings of 85 lesions in 75 patients aged 31-89 years were retrospectively reviewed. The biopsies were performed as part of the patients' clinical care with a Food and Drug Administration-approved biopsy system and not within a research protocol. All included patients had received a diagnosis of malignant, benign, or high-risk (for cancer) breast tissue at core-needle biopsy and had undergone subsequent surgery or follow-up imaging. MR imaging-guided biopsy results were compared with final histopathologic or follow-up imaging findings.

RESULTS

At MR imaging-guided core-needle biopsy, malignancy was identified in 52 (61%) lesions: 35 invasive cancers and 17 ductal carcinoma in situ (DCIS) lesions. Four (24%) of the 17 DCIS lesions were upgraded to invasive cancer at excisional biopsy or mastectomy. A high-risk lesion (ie, atypical ductal hyperplasia, atypical lobular hyperplasia, lobular carcinoma in situ, or radial scar) was identified in 18 (21%) cases. Two (25%) of eight atypical ductal hyperplasia lesions were upgraded to DCIS at excision. No malignancy was found in the atypical lobular hyperplasia (n = 2), lobular carcinoma in situ (n = 5), or radial scar (n = 3) lesions. Fifteen (18%) lesions were found to be benign lesions of unknown type at excision or mastectomy. For 13 of these 15 lesions, the benign results were concordant with the imaging findings. Both (two of 86, 2%) discordant cases represented false-negative lesions. The remaining 13 benign lesions were validated at excisional biopsy (n = 9) or follow-up imaging (n = 4).

CONCLUSION

Initial experience revealed MR imaging-guided 9-gauge vacuum-assisted core-needle breast biopsy to be a reasonable alternative to MR imaging-guided wire localization of suspicious lesions identified at MR imaging only, on the basis of published information regarding the latter.

MR-guided breast biopsy using an active marker: A phantom study

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.

Percutaneous Biopsy from Blinded to MR Guided: An Update on Current Techniques and Applications

The advent of interventional MR imaging techniques as well as their adoption to guide percutaneous biopsies and aspirations has served as a further step along a series of technical refinements that commenced with the implementation of image-guided approaches for tissue sampling. Nowadays, the practice of and the expectations from these procedures are quite different from those of the blind percutaneous thrusts performed in the late nineteenth and early twentieth centuries. As the field of interventional MR imaging continues to flourish and to attract more radiologists who realize the many opportunities that this technology can offer to their patients, there is a need for a full comprehension of the concepts, techniques, limitations, and cost-effectiveness of MR imaging guidance to present this service to clinical partners in the appropriate setting. Radiologists should also recognize the need for their significant involvement in the technical aspects of MR-guided procedures, because several user-defined parameters and trajectory decisions can alter device visualization in the MR imaging environment and hence affect procedure safety.

MRI-Guided 9-Gauge Vacuum-Assisted Breast Biopsy: Initial Clinical Experience

OBJECTIVE

The objective of this study was to evaluate our initial clinical experience with MRI-guided vacuum-assisted breast biopsy as an alternative to surgical excision.

MATERIALS AND METHODS

A retrospective review revealed 112 consecutive nonpalpable, mammographically occult MRI-detected breast lesions scheduled for MRI-guided vacuum-assisted biopsy. Biopsy was performed with a 9-gauge vacuum-assisted biopsy probe (Suros Surgical Systems) followed by clip placement (Artemis Medical). Medical records and histologic findings were reviewed.

RESULTS

Among 112 lesions, biopsy was cancelled because of nonvisualization of the lesion in 14 (12%). Of the remaining 98 lesions, tissue was successfully acquired in 95 (97%). The median number of specimens obtained was 12 (range, 6-20). The median time to perform MRI-guided biopsy was 33 min for one lesion and 56 min for two lesions. Histology in 95 lesions was benign and concordant in 52 (55%), cancer in 24 (25%), high-risk in 10 (11%), and discordant in nine (9%). MRI-guided biopsy histologies in 24 cancers were ductal carcinoma in situ in 13 (54%) and infiltrating carcinoma in 11 (46%). Seven additional cancers were found at surgery in four discordant lesions and in three high-risk lesions. The clip successfully deployed in 86 (95%) of 91 lesions. Six complications (three hematomas, two instances in which the biopsy probe pierced the skin on the far side of the breast, and one vasovagal reaction) resolved without sequelae.

CONCLUSION

MRI-guided vacuum-assisted biopsy is a fast and safe alternative to surgical biopsy for MRI-detected breast lesions. Imaging-histologic correlation is necessary to ensure lesion sampling.

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.

Magnetic Resonance-Guided Biopsies and Localizations of the Breast

OBJECTIVE

The objective of this study was to evaluate the performance of a new commercially available open breast coil and compatible intervention device (Machnet) for magnetic resonance image (MRI)-guided breast interventions.

MATERIALS AND METHODS

Breast lesions detected on MRI were evaluated using MRI-guided core biopsy (n = 20) and/or preoperative wire localization (n = 23) on histologic outcome and accuracy of localization. Time needed to perform a procedure and occurring problems were recorded.

RESULTS

Mean lesion size was <10 mm. Two of 20 lesions could not be biopsied because they were out of range for the device. Biopsies were conclusive in half of the cases; most lesions missed were <10 mm. The average accuracy for needle placement in the localization procedures was less than 2 mm (range, 0-5 mm). The average procedure time was 40 minutes for a biopsy procedure and 33 minutes for an MRI-guided localization.

CONCLUSIONS

Preoperative MRI-guided localizations can be performed quickly and accurately. However, in MRI-guided core biopsies, especially in small lesions, the device does not guarantee conclusive histologic evaluation of the lesion targeted.

MRI-Guided Breast Biopsy:Clinical Experience with 14-Gauge Stainless Steel Core Biopsy Needle

OBJECTIVE

Core needle biopsy has proven advantages for wire localization and excision; however, MRI-guided core biopsy has been limited by less satisfactory sampling efficiency and less availability of MRI-compatible biopsy needles. We evaluated the feasibility and diagnostic yield of MRI-guided biopsy using 14-gauge stainless steel core biopsy needles and MRI-compatible coaxial sheaths in a closed 1.5-T scanner.

MATERIALS AND METHODS

Thirty-five consecutive breast biopsies performed in 29 women between March 2001 and August 2002 were retrospectively reviewed. For each procedure, an MRI-compatible sheath was placed under MRI guidance using a dedicated breast coil and biopsy guidance system. With the patient out of the magnet, a 14-gauge steel core biopsy needle was used to obtain multiple samples. Lesion characteristics, including size, morphology, and enhancement, were recorded. Histology of all the lesions was obtained; and surgical, imaging, or clinical follow-up was performed.

RESULTS

Targeted masses and enhancing foci ranged from 3 to 17 mm. Regional enhancement ranged from 14 to 70 mm. Thirty-four of the 35 biopsies were technically successful. Histology revealed malignancy in eight lesions (23%), atypical ductal hyperplasia in five lesions (14%), and benign entities in 21 lesions (60%). Surgery confirmed all eight core biopsies with malignant findings. Two of five lesions with atypical ductal hyperplasia were upgraded to malignancy after surgery.

CONCLUSION

This new method of MRI-guided breast biopsy with a 14-gauge stainless steel core biopsy needle and a closed 1.5-T MRI scanner is feasible, safe, and effective and produces satisfactory diagnostic yield. This method offers an alternative to MRI-guided wire localization and to MRI-guided core biopsy with nonferrous needles.

Fast MRI-Guided Vacuum-Assisted Breast Biopsy:Initial Experience

OBJECTIVE

The purpose of this study was to evaluate a new method for performing MRI-guided vacuum-assisted breast biopsy in a study of lesions that had subsequent surgical excision. SUBJECTS AND METHODS. Twenty women scheduled for MRI-guided needle localization and surgical biopsy were prospectively entered in the study. MRI-guided biopsy was performed with a vacuum-assisted probe, followed by placement of a localizing clip, and then needle localization for surgical excision. Vacuum-assisted biopsy and surgical histology were correlated.

RESULTS

Vacuum-assisted biopsy was successfully performed in 19 (95%) of the 20 women. The median size of 27 MRI-detected lesions that had biopsy was 1.0 cm (range, 0.4-6.4 cm). Cancer was present in eight (30%) of 27 lesions and in six (32%) of 19 women; among these eight cancers, five were infiltrating and three were ductal carcinoma in situ (DCIS). Among these 27 lesions, histology was benign at vacuum-assisted biopsy and at surgery in 19 (70%), cancer at vacuum-assisted biopsy in six (22%), atypical ductal hyperplasia at vacuum-assisted biopsy and DCIS at surgery in one (4%), and benign at vacuum-assisted biopsy with surgery showing microscopic DCIS that was occult at MRI in one (4%). The median time to perform vacuum-assisted biopsy of a single lesion was 35 min (mean, 35 min; range, 24-48 min). Placement of a localizing clip, attempted in 26 lesions, was successful in 25 (96%) of 26, and the clip was retrieved on specimen radiography in 22 (96%) of 23. One complication occurred: a hematoma that resolved with compression.

CONCLUSION

MRI-guided vacuum-assisted biopsy is a fast, safe, and accurate alternative to surgical biopsy for breast lesions detected on MRI.

A hybrid breast biopsy system combining ultrasound and MRI

System design and initial phantom accuracy results for a novel biopsy system integrating both magnetic resonance (MR) and ultrasound (US) imaging modalities are presented. A phantom experiment was performed to investigate the efficacy of this hybrid guidance biopsy technique in a breast tissue mimicking phantom. A comparison between MR-guided core biopsy verses MR/US-guided core biopsy of phantom targets was realized using a scoring system based on the consistency of the acquired core samples (14 gauge). It was determined that the addition of US to guide needle placement improved the accuracy from an average score of 7.4 out of 10 (MRI guidance alone), to 9.6 (MRI/US guidance) over 21 trials. The average amount of needle tip correction resulting from the additional US information was determined to be 3.7 mm. This correction value is substantial, equal to approximately one radius of the intended targets. Hybrid US/MRI guided biopsy appears to offer a simple means to ensure accurate breast tissue sampling without the need for repeat MRI scans for verification or the need for real-time imaging in open MRI geometries.

MR-guided interventional breast procedures considering vacuum biopsy in particular

Histologic work-up of just MR-detected breast lesions has become essential with increasing use of contrast-enhanced MR imaging. In the present article an overview is given about the different MR-guided breast interventions, performed since 1990. Presently, for reasons of costs and image quality closed magnets are most widely used. The following approaches have been described: MR-guided freehand localization in supine position, stereotaxic localization in supine position and most frequently used localization in the prone position by means of a compression device that immobilises the breast to prevent tissue shift during intervention. Only limited experience exists with interventions on open magnets. MR-guided wire localization is a well-established procedure. Recently, percutaneous vacuum biopsy of enhancing breast lesions has become possible under MR guidance. The new system allows accurate and safe access to lesions in any location of the breast and direct check-up of representative excision by visualisation of the cavity. Thus reliable histologic evaluation of lesions smaller than 10 mm is possible with this approach.

Methods for modeling and predicting mechanical deformations of the breast under external perturbations

Currently, high field (1.5 T) superconducting MR imaging does not allow live guidance during needle breast procedures. The current procedure allows the physician only to calculate approximately the location and extent of a cancerous tumor in the compressed patient breast before inserting the needle. It can then become relatively uncertain that the tissue specimen removed during the biopsy actually belongs to the lesion of interest. A new method for guiding clinical breast biopsy is presented, based on a deformable finite element model of the breast. The geometry of the model is constructed from MR data, and its mechanical properties are modeled using a non-linear material model. This method allows imaging the breast without or with mild compression before the procedure, then compressing the breast and using the finite element model to predict the tumor's position during the procedure. A silicon phantom containing a stiff inclusion was imaged uncompressed then compressed. A model of the phantom was constructed and compressed using custom-written software, and also using a commercial FEM simulation package. The displacement of the inclusion's corners was recorded both in the real phantom and in the two compressed models. A patient's breast was imaged uncompressed then compressed. A deformable model of the uncompressed breast was constructed, then compressed. The displacement of a cyst and of two vitamin E pills taped to the surface of the breast were recorded both in the real and in the modeled breast. The entire procedure lasted less than a half-hour, making it clinically useful. The results show that it is possible to create a deformable model of the breast based on finite elements with non-linear material properties, capable of modeling and predicting breast deformations in a clinically useful amount of time.

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

BACKGROUND

Breast magnetic resonance imaging (MRI) has been reported to be twice as sensitive and three times more specific in detecting breast cancer. We report a series of MRI-guided stereotactic breast biopsies (SCNBB) and needle localized breast biopsies (NLBB) to evaluate MRI as a localization tool.

METHODS

Forty-one breast lesions were identified in 39 patients who subsequently had SCNBB or NLBB. Suspicious areas of enhancement were stereotactically biopsied with 16-G core biopsy needles or localized with 22-G wires for excision under laser guidance.

RESULTS

Forty-one breast lesions were identified from 1,292 breast MRIs. SCNBB identified three malignancies and two areas of atypia. Two additional cancers were found after NLBB. In patients having NLBB alone, five cancers and two areas of atypia were identified.

CONCLUSIONS

In this initial series, breast MRI-guided SCNBB and NLBB were valuable tools in the management of patients with suspicious abnormalities seen only on MRI.

Magnetic resonance imaging of the breast

BACKGROUND

Magnetic resonance imaging (MRI) has the potential to become a useful adjunct in breast imaging. Contrast-enhanced breast MRI has demonstrated a high sensitivity in the detection of invasive breast cancer. In clinical studies, breast MRI has often altered the course of patient care. Although promising results have been generated, MRI of the breast is currently in a development stage.

METHODS

The authors reviewed the literature on the potential indications, sensitivity, specificity, and limitations of MRI of the breast.

RESULTS

Reported advantages of MRI of the breast over conventional imaging techniques include improved staging and treatment planning, enhanced evaluation of the augmented breast, better detection of recurrence, and improved screening of high-risk women. Contrast-enhanced breast MRI is a sensitive modality for detecting breast cancer, but its variable specificity is a major limitation.

CONCLUSIONS

MRI of the breast is emerging as a valuable adjunct to mammography and sonography for specific clinical indications. Additional clinical studies that define indications, interpretation criteria, imaging parameters, and cost effectiveness are needed. A multi-institutional study designed to address these issues is in progress.

An apparatus for MR-guided breast lesion localization and core biopsy: design and preliminary results

System design and initial results are presented from a new unilateral MR-guided breast lesion localization and core biopsy system. Over 150 imaging studies, an accuracy study on phantoms with 50 localization wire deployments and 33 core biopsy trials, and 19 clinical procedures are reported. The mean spatial accuracy from the lesion center for a 20-gauge (G) needle (N = 13) was within 1.2 +/- 1.4 mm (SD) and for a 14G biopsy (N = 4) 0.8 +/- 1.1 mm. For sampling using a 16G core through a 14G needle, the mean accuracy was 5.6 mm (N = 2). The needle guide geometry imposed a small, calculable targeting error. For phantom measurements using the 20G device, the mean geometry-induced error was 0.73 +/- 0.43 mm. However, this contribution was, on average, 42% of the mean measured 2.35 +/- 1.65 mm offset. The new device design provided an accurate and simple guidance method for localization or core biopsy of MR-visible breast lesions.

MR imaging of the breast for the detection, diagnosis, and staging of breast cancer

With the introduction of contrast agents, advances in surface coil technology, and development of new imaging protocols, contrast agent-enhanced magnetic resonance (MR) imaging has emerged as a promising modality for detection, diagnosis, and staging of breast cancer. The reported sensitivity of MR imaging for the visualization of invasive cancer has approached 100%. There are many examples in the literature of MR imaging--demonstrated mammographically, sonographically, and clinically occult breast cancer. Often, breast cancer detected on MR images has resulted in a change in patient care. Despite these results, there are many unresolved issues, including no defined standard technique for contrast-enhanced breast MR imaging, no standard interpretation criteria for evaluating such studies, no consensus on what constitutes clinically important enhancement, and no clearly defined clinical indications for the use of MR imaging. Furthermore, this technology remains costly, and issues of cost-effectiveness and cost competition from percutaneous biopsy have yet to be fully addressed. These factors along with the lack of commercially available MR imaging--guided localization and biopsy systems have slowed the transfer of this imaging technology from research centers to clinical breast imaging practices. Technical requirements, potential clinical applications, and potential pitfalls and limitations of contrast-enhanced MR imaging as a method to help detect, diagnose, and stage breast cancer will be described.

Freehand iMRI-guided large-gauge core needle biopsy: a new minimally invasive technique for diagnosis of enhancing breast lesions

The lack of reliable methods for minimally invasive biopsy of suspicious enhancing breast lesions has hindered the utilization of contrast-enhanced magnetic resonance imaging (MRI) for the detection and diagnosis of breast cancer. In this study, a freehand method was developed for large-gauge core needle biopsy (LCNB) guided by intraprocedural MRI (iMRI). Twenty-seven lesions in nineteen patients were biopsied using iMRI-guided LCNB without significant complications. Diagnostic tissue was obtained in all cases. Nineteen of the 27 lesions were subsequently surgically excised. Histopathologic analysis confirmed that iMRI-guided LCNB correctly distinguished benign lesions from malignancy in 18 of the 19 lesions. The histology revealed by core biopsy was partially discrepant with surgical biopsy in 2 of the other 19 lesions. Freehand iMRI-guided LCNB of enhancing breast lesions is promising. Larger studies are needed to determine the smallest lesion that can be sampled reliably and to precisely measure the accuracy of iMRI-guided LCNB as a minimally invasive tool to diagnose suspicious lesions found by breast MRI. J. Magn. Reson. Imaging 2001;13:896-902.

MR imaging: breast cancer staging and screening

This review describes the current knowledge and challenges of breast cancer staging and screening with MRI of the breast. Assessment of local disease extent, including tumor size, multicentricity, and chest wall invasion, can be obtained more accurately with MRI than with mammography. Moreover, international experts have established standardized reporting of MRI staging results, taking into account tumor size measurements and the number of breast quadrants involved. Results from MRI assessment of the axilla and skin are promising, but need further refinement. Preliminary results of the use of breast MRI in patients at high risk for breast cancer demonstrated a superiority of breast MRI over the combined use of mammography and high-frequency ultrasound. The role of MRI in this subset of patients may be confirmed by ongoing larger multicenter trials. Strict protocol conditions are mandatory to maintain a high standard of quality. Confirming the nature of "MRI-only" lesions with MRI-guided biopsy systems will allow changes in treatment planning. More accurate tumor diagnosis and tumor volume evaluation may allow minimally invasive treatment strategies.

Magnetic resonance imaging of breast cancer: clinical indications and breast MRI reporting system

Magnetic resonance imaging (MRI) is well suited to the investigation of breast cancer by virtue of its noninvasive nature and its multiplanar imaging abilities. MRI investigations showed high sensitivity but modest specificity for breast cancer detection and diagnosis. Most early studies tested the ability of MRI to evaluate and diagnose findings in the breast discovered by other imaging tests or by breast physical examination (1-4). When it was discovered that MRI identified small breast cancers undetected by mammography or breast ultrasound, MRI was used to estimate breast cancer extent in known cancer cases for surgical planning (5,6). These investigations led to the use of MRI in a multitude of breast imaging applications, raising further questions about the use of MRI in everyday practice: What are the indications for breast MRI in general practice? What is its role in light of other imaging tests? What are its benefits and limitations in each setting? How do I report these studies? The purpose of this article is to review the clinical background regarding indications for the use of MRI and relevant cases in which MRI can impact patient management in breast disease, and to describe new developments in reporting breast MRI studies. J. Magn. Reson. Imaging 2000;12:975-983.

MR imaging of the breast

The results of clinical investigation suggest that MR imaging can provide clinically important information that cannot be obtained with conventional imaging methods, and that this modality will, in the future, be an invaluable adjunctive breast imaging tool just as breast ultrasound is today. MR imaging appears to be the most accurate method for the detection of implant failure, and although it is the most costly of the available implant imaging techniques, it may be the study of choice when there is a question of implant integrity that cannot be answered with conventional methods. MR imaging as a method to detect, diagnose, and stage breast cancer remains in the investigational stage. The specificity of MR imaging appears limited because of the overlap in the enhancement kinetics and morphologic appearance of benign and malignant lesions. In selected cases, the identification of certain morphologic features, such as internal septations or the absence of enhancement, may be used to classify a lesion as benign, offering an alternative to percutaneous or excisional biopsy. MR imaging appears to be very sensitive for the visualization of both invasive carcinoma and DCIS. Perhaps most important, MR imaging can detect invasive and noninvasive breast carcinoma that is both mammographically and clinically occult, offering the potential for more accurate breast cancer staging and optimized treatment planning. MR imaging is emerging as perhaps the most promising imaging modality for breast cancer detection to date. Published results, however, are from studies with relatively small numbers of patients. The results of these studies should be validated in a large-scale clinical trial before MR imaging is implemented clinically, outside of research settings. This type of clinical investigation is needed to define the technical requirements for optimal imaging, to define interpretation criteria, to develop accurate MR imaging guided localization and biopsy systems, to define the clinical indications for which MR imaging should be used as an adjunct to conventional imaging methods, and to address the issue of cost-effectiveness. One such trial, an international, multi-institutional study funded by the National Cancer Institute, is presently underway.

Localization of breast lesions shown only on MRI--a review for the UK Study of MRI Screening for Breast Cancer. Advisory Group of MARIBS

The UK study of screening for breast cancer compares mammography and dynamic contrast enhanced MRI of the breast in women at high genetic risk of developing cancer. Owing to the high sensitivity of MR in the breast, it is anticipated that some lesions will be visible only on MR. A key issue for the study is how to localize these lesions for histological verification and removal. This article reviews available methods and describes the current UK expertise and recent European developments. The use of MR compatible wires and markers has been explored in a phantom. The use of these markers in vivo is demonstrated in a case imaged by MR and mammography and further discussed. The susceptibility artefacts produced on MRI, and technical properties associated with these needles, wires and markers are discussed. The clinical pathway by which these lesions will be worked up for the study, and the quality control procedures for keeping the number of such biopsies to a minimum, are described. There is an urgent need for further centres in the UK to become proficient at removing lesions found only on MRI in support of this study and other breast MRI applications. The management of these lesions must be resolved in order to realize the full potential of MRI for screening for breast cancer in women at genetic risk, and for other diagnostic applications.

Breast carcinoma: effect of preoperative contrast-enhanced MR imaging on the therapeutic approach

PURPOSE

To determine if magnetic resonance (MR) imaging can help determine the therapeutic approach in women with breast cancer.

MATERIALS AND METHODS

Preoperative contrast-enhanced MR imaging of the breast was performed in 463 patients with probably benign lesions (n = 63), suspicious lesions (n = 230), or lesions highly suggestive of malignancy (n = 170) per established clinical, mammographic, and/or ultrasonographic (US) criteria. T1-weighted fast low-angle shot MR imaging was performed before and after administration of gadopenetetate dimeglumine. MR imaging findings were correlated with other imaging results and histopathologic findings. Special attention was paid to multifocality and multicentricity.

RESULTS

Histopathologic analysis revealed 143 benign and 405 malignant lesions. The sensitivity, specificity, and accuracy were 58%, 76%, and 62% for clinical examination; 86%, 32%, and 72% for conventional mammography; 75%, 80%, and 76% for US; and 93%, 65%, and 85% for contrast-enhanced MR imaging. Multifocality in 30 of 42 patients, multicentricity in 24 of 50 patients, and additional contralateral carcinomas in 15 of 19 patients were depicted with MR imaging alone. Due to the MR imaging findings, therapy was changed correctly in 66 patients (14.3%); unnecessary open biopsy was performed in 16 patients (3.5%).

CONCLUSION

Contrast-enhanced MR imaging of the breast is highly sensitive for invasive breast cancer. MR imaging may reveal unsuspected multifocal, multicentric, or contralateral breast carcinoma and result in therapy changes.

Breast magnetic resonance imaging

Breast MRI is becoming an important tool for the improved management of breast cancer. The technical attributes of high contrast, high-resolution breast MRI acquisitions are summarized. The fundamentals of image interpretation are outlined, including lesion enhancement, morphological features, and extent categories. The indications for breast MRI include compromised mammography, staging of disease within the breast and adjacent structures, difficult histology, and other special diagnostic situations. Patients with compromised mammography include previous surgery, radiographically dense breasts, and silicone augmentation. The improved determination of disease extent aids in the management of breast conservation treatment. Certain lesions, particularly lobular carcinoma and ductal carcinoma in situ, can be better managed with the information available with breast MRI. Other potential indications are also discussed, including patients presenting with positive axillary nodes and no known primary, women with a high risk of malignancy, and recently postoperative breasts with positive margins. The need for MRI stereotaxis is reviewed, with indications and potential solutions. The potential future roles for MRI-directed interstitial hyperthermia are outlined.

MRI in breast cancer diagnosis and treatment

Breast cancer diagnosis and treatment are important health care issues in the Industrialized World. About 180,000 new breast cancers are discovered annually in the United States. Because this cancer often occurs in premenopausal women, breast cancer is a leading cause of potential life years lost. Breast magnetic resonance imaging (MRI) is capable of producing detailed information concerning the extent and character of breast lesions. The technique and alternatives for generating high-resolution breast MR images are reviewed. Characteristic features of a pulse sequence for breast imaging includes heavy T1 weighting and magnetization transfer weighting for more effective gadolinium contrast, fat suppression, and rapid acquisition time. MRI is best employed for breast cancer diagnosis as a supplement to conventional breast imaging. Diagnostic groups particularly well suited to breast MRI include women with radiographically dense breasts, silicone augmentation, and postoperative scar. The capacity of breast MRI to show disease extent is employed to plan and localize for breast-conservation therapy. Tumor size and multiple tumors can be characterized for more-effective surgical management. Ductal carcinoma in situ can be imaged and staged for tailored therapy. MRI-directed biopsy and localization can be used to optimize lumpectomy surgery and reduce the potential for histologically positive margins. MRI can define the effectiveness of radiation therapy and chemotherapy to provide improved information on nonsurgical treatment of breast cancer. The clinical implementation of breast MRI in the future depends on the careful coordination of quality MRI images and interpretations with skillful therapeutic management.

High-resolution MR imaging of the breast

Investigation into the use of MRI as a breast imaging tool is ongoing. Several studies have shown that MRI is a very accurate imaging method for the identification of implant failure in the symptomatic patient with augmented breasts. In this clinical setting. MRI may be the study of choice. Imaging techniques, and the MRI appearance of normal and abnormal implants, are described. The use of MRI for the detection of breast cancer is not as straightforward. Preliminary results suggest that this technique can be used as an adjunct to mammography for the detection and diagnosis of breast cancer. However, it is premature to draw firm conclusions regarding the role that MRI should play in the management of women with breast disease because of the wide variability of imaging techniques, protocols, and patient populations in the studies reported to date. In this overview, the current state of MR imaging of the breast is discussed. Technical requirements are described, and potential clinical applications- including the differentiation of benign from malignant lesions, breast cancer staging, detection of recurrence after breast conservation therapy, and detection of cancer in patients presenting with positive axillary lymph nodes with an unknown primary-are reviewed. Many of these potential clinical applications will require an accurate MR-guided biopsy system, and the implementation of such a system as well as its inherent limitations are discussed.

Visualization of magnetic resonance-compatible needles at 1.5 and 0.2 Tesla

PURPOSE

For two types of passively visualizable magnetic resonance (MR)-compatible needles, the size of susceptibility artifacts was investigated at 0.2 and 1.5 Tesla (T) and assessed regarding their suitability for needle visualization.

METHODS

Phantom trials were performed using T1-weighted spin echo (SE), turbospin echo (TSE) and gradient echo (GE) sequences and different angles beta between the needles and the main magnetic field (B0).

RESULTS

Depending on the needle angle beta and the applied pulse sequence, we found artifact diameters of 0-9.7 mm employing SE, of 1.7-9.4 mm employing TSE, and of 1.4-20.6 mm employing GE at 1.5 T. At 0.2 T, we found artifact diameters of 0-5.7 mm employing SE, of 0-6.3 mm employing TSE, and of 0-11.3 mm employing GE.

CONCLUSION

Comparing artifact sizes at 1. 5 T and 0.2 T, low field strength is superior for passive visualization of the needles tested-especially if GE imaging is performed.

Dynamic gradient-echo and fat-suppressed spin-echo contrast-enhanced MRI of the breast

PURPOSE

To evaluate heavily T2-weighted, dynamic contrast-enhanced and fat-suppressed magnetic resonance imaging (MRI) of the breast in comparison with conventional imaging and fine needle aspiration cytology (FNAC).

PATIENTS AND METHODS

Fifty patients with surgically/pathologically proven breast disease were examined pre-operatively by MRI. The majority, 45 patients, had invasive carcinoma. T1-weighted spin-echo, T2-weighted fast spin-echo (with chemical-shift-selective fat-suppression in 20 cases), rapid dynamic contrast-enhanced gradient-echo and post-contrast fat-suppressed T1-weighted images were obtained. Signal intensity changes during dynamic scanning were assessed qualitatively and quantitatively. Comparison was made with the results of X-ray mammography, ultrasound and fine needle aspiration cytology.

RESULTS

Unenhanced MRI was inadequate for determining the location, extent or nature of most lesions even when fat-suppressed T2-weighted images were obtained. Following contrast injection, there was significantly greater enhancement of invasive carcinomas than normal parenchyma. Invasive carcinomas of ductal and lobular subtypes did not differ significantly in their enhancement profiles. Prominent enhancement of the lesion periphery, which was a feature in 33 out of 50 cases (the majority of which were invasive carcinomas) was not due to central tumour necrosis. In four cases, invasive carcinomas which were clearly visible on early dynamic scans could not be identified on post-contrast fat-suppressed images. Lesions that were more numerous or extensive than had been recognised clinically or mammographically were revealed by MRI in 14 patients, though MRI was no more specific than conventional assessment. Invasion of the chest wall was accurately predicted by MRI in three cases. There was excellent correlation between tumour size shown by MRI and histopathology. FNAC was accurate in predicting the final histological diagnosis except in those cases where samples were unsatisfactory.

CONCLUSIONS

Contrast-enhanced MRI appears useful in the assessment of suspected malignant breast masses, especially in younger women with predominantly glandular breast tissue. Specificity is no better than FNAC but tumour extent and multifocality are more accurately disclosed than by conventional imaging techniques. Contrast-enhanced chemical-shift-selective fat-suppressed images are sub-optimal in a small proportion of cases (particularly where lesions are located posteriorly) and some benign breast disease may appear misleadingly conspicuous on such images. Morphological features and quantification of lesion enhancement during dynamic scanning presently offer only limited prospects for discrimination between various pathologies. Heavily T2-weighted sequences appear of marginal value.