Dedicated double breast coil for magnetic resonance mammography imaging, biopsy, and preoperative localization

Percutaneous needle biopsy under 1.2 Tesla open MRI guidance

PURPOSE

To evaluate the feasibility of percutaneous needle biopsy using a 1.2 Tesla open magnetic resonance imaging (MRI) system, which has the highest field strength among the currently available open MRI systems.

MATERIALS AND METHODS

This single-center prospective study included 10 patients. The primary endpoint was the feasibility of biopsy needle insertion into a target lesion under 1.2 Tesla open MRI guidance. The secondary endpoints included adverse events, device failures, and success of tissue specimen acquisition. Biopsy was performed for targets in various organs using an MRI-compatible coaxial needle system consisting of a 16G introducer needle and 18G semi-automatic biopsy needle. A newly developed body coil with a suitable design for intervention was used for intraprocedural imaging.

RESULTS

Biopsy procedures were performed for six musculoskeletal masses, two retroperitoneal masses, one renal mass, and one liver mass. The median diameter of the targets was 4.9 cm (range 2.1-22.8 cm). MRI-guided biopsy needle insertion was feasible in all 10 patients. In total, four grade 1 adverse events (as per Common Terminology Criteria for Adverse Events version 4.0) occurred in three patients. Adequate biopsy specimens for pathological diagnosis were successfully obtained from all 10 patients.

CONCLUSION

Percutaneous needle biopsy using a 1.2 Tesla open MRI system was feasible for relatively large targets, especially in the musculoskeletal region.

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.

Two-year follow-up of stereotactically guided 9-G breast biopsy: a multicenter evaluation of a self-contained vacuum-assisted device

PURPOSE

To evaluate the performance of a self-contained, battery-driven, vacuum-assisted breast biopsy (VABB) system for the sampling of clustered breast microcalcifications and masses under stereotactic guidance.

METHODS AND MATERIALS

A total of 144 patients (median age: 56 years; range: 21-87 years) in four European breast centers underwent percutaneous 9-gauge (G), stereotactic-guided VABB. The median lesion size was 11 mm (range 2-60 mm). Patients were biopsied in the prone (n=125) or upright position (n=19). All patients were followed up for at least 24 months.

RESULTS

The stereotactic procedure was successful in 142 (98.6%) of 144 cases, with two cases cancelled due to either severe patient motion (one case) or failure to detect faint calcifications (one case). A median of 12 specimens per procedure was obtained. In 39 cases (27.5%), the suspicious lesion could no longer be detected mammographically after the biopsy procedure. The histological diagnosis was malignancy in 45 (31.7%) cases. One case of atypical ductal hyperplasia diagnosed preoperatively was upgraded to ductal carcinoma in situ (DCIS) at operation, giving an overall sensitivity of 97.7% for the vacuum-assisted biopsy procedure. In two cases where DCIS was diagnosed at vacuum-assisted biopsy, the malignant tissue was apparently completely removed and could no longer be found at operation. No serious complications occurred. During the follow-up period, no breast cancers appeared at the location of biopsy. Six patients dropped out during the follow-up period.

CONCLUSION

The self-contained, vacuum-assisted biopsy device is well suited for stereotactically guided breast biopsies, having demonstrated excellent sensitivity and specificity in the preoperative workup of mammographically detected breast lesions after 2 years of follow-up.

MRI-guided interventions of the breast

MRI has proven to be a very reliable diagnostic tool in the detection and differential diagnosis of breast lesions. Some lesions are, even in retrospect, not detectable in x-ray or ultrasound images but MRI is able to detect lesions at a much smaller size than the average size of lesions depicted by x-ray and ultrasound. The aim in the future is to develop combined procedures where imaging, biopsy, and interventional therapies are combined in a single outpatient procedure. As a step toward this goal different interventional procedures are useful that include interstitial laser therapy (ILT), radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), microwave ablation therapy, and cryotherapy. In this overview the main features and initial results of these procedures are described and discussed.

Targeting difficult accessible breast lesions: MRI-guided needle localization using a freehand technique in a 3.0T closed bore magnet

PURPOSE

To report the accuracy of magnetic resonance imaging (MRI)-guided needle localization for diagnosis of MRI detected suspicious breast lesions located in difficult accessible regions of the breast, using the freehand method in a 3.0 T closed bore magnet.

MATERIALS AND METHODS

In five patients with five MRI-only breast lesions underwent MRI-guided needle localization for histopathologic evaluation of the lesions. All interventional procedures were performed in a 3.0 T MRI system with the patient in prone position and by using a dedicated phased array breast coil. MRI-guided needle localizations were performed by using a freehand technique. In our study, the high-resolution scan allowed preprocedural localization of all lesions without use of contrast enhancement. In all cases contrast-enhanced MRI was performed after insertion of the wire to confirm the tip of the wire in direct contact with the enhancing lesion.

RESULTS

Needle localizations were performed in five patients. Histopathologic evaluation of tissue after surgery excision biopsy revealed one lymph node, three invasive ductal carcinoma and one ductal carcinoma in situ. Lesion size varied from 6 to 30 mm. Mean duration time was 25 min. No complications occurred during the intervention method. In the patient with the benign lesion control MRI of the breast after 6 months confirmed lesion removal.

CONCLUSIONS

MRI-guided needle localization by using a freehand technique in a 3.0 T closed bore magnet is a safe and accurate method for diagnosis of difficult accessible breast lesions only visible on MRI.

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.

Ultrasound-guided, percutaneous cryotherapy of small (< or = 15 mm) breast cancers

RATIONALE AND OBJECTIVE

The purpose of this study was to investigate the feasibility, efficacy, and safety of ultrasound-guided percutaneous cryotherapy of stage T1 breast cancers.

MATERIALS AND METHODS

Thirty patients with biopsy-confirmed breast cancers with tumor diameters of 15 mm or smaller (range, 5-15 mm; median, 12 mm) underwent cryotherapy. After local anesthesia, a 3-mm cryo probe was placed into the tumor under ultrasound guidance. All tumors were subjected to 2 freeze cycles with an interposing thawing cycle. The size of the ice-balls, their distance to the skin, and the temperature at the tip of the probe were closely monitored during the procedure. The patients underwent surgery within 6 weeks and the specimens were evaluated histologically.

RESULTS

The median minimum temperature reached -146 degrees C (range, -117 degrees C to -167 degrees C). In 5 of 29 patients, remnant ductal carcinoma in situ was detectable histologically after cryotherapy beyond the margin of the cryosite in the specimens after open surgery. In 24 patients, no viable tumor cells were found. No severe side effects occurred. In one patient, the cryo procedure was not performed completely because of technical problems.

DISCUSSION

Percutaneous cryotherapy is a feasible and safe procedure in minimally invasive therapy for small breast cancers. Residual ductal carcinoma in situ may be attributable to the beginning of a learning curve or by false-negative detection in pre-interventional imaging. Magnetic resonance mammography might aid in treatment planning and for therapy monitoring to better define target tissue and to correlate the tumor margin with the ice-ball.

Aspectos técnicos da ressonância magnética de mama com meio de contraste: revisão da literatura

Com a difusão do uso de meios de contraste, avanços na tecnologia das bobinas de superfície e desenvolvimento de protocolos rápidos de aquisição de imagens, a ressonância magnética (RM) de mama com meio de contraste tem-se mostrado importante modalidade na detecção, diagnóstico e estadiamento do câncer de mama. Apesar desses avanços, existem alguns pontos não consensuais no que diz respeito aos aspectos técnicos e critérios de interpretação de imagem da RM contrastada de mama. Neste artigo fazemos revisão bibliográfica dos parâmetros de interpretação de imagens e aspectos técnicos da RM de mama, incluindo considerações sobre a "performance" do equipamento, bobinas de radiofreqüência dedicadas, modo de utilização de contraste paramagnético, técnicas de supressão de gordura, planos de aquisição, seqüências de pulso e fontes de artefato.

Magnetic Resonance Imaging Characteristics of Fibrocystic Change of the Breast

OBJECTIVE

The objective of this study was to identify magnetic resonance imaging (MRI) characteristics of fibrocystic change (FCC) of the breast.

MATERIALS AND METHODS

Fourteen patients with a histopathologic diagnosis of solitary FCC of the breast underwent x-ray mammography and MRI of the breast. Three experienced breast imaging radiologists retrospectively reviewed the MRI findings and categorized the lesions on morphologic and kinetic criteria according to the ACR BI-RADS-MRI Lexicon.

RESULTS

The most striking morphologic feature of fibrocystic change was nonmass-like regional enhancement found in 6 of 14 (43%) FCC lesions. Based on morphologic criteria alone, 12 of 14 (86%) lesions were correctly classified as benign. According to analysis of the time-intensity curves, 10 of 14 (71%) FCC lesions were correctly classified as benign.

CONCLUSION

Although FCC has a wide spectrum of morphologic and kinetic features on MRI, it most often presents as a mass or a nonmass-like regional enhancing lesion with benign enhancement kinetics.

Preoperative Magnetic Resonance Imaging-Guided Localization of 131 Breast Lesions With Modified Embolization Coils

OBJECTIVES

The objectives of this study were to assess practicability, outcome, and possible advantages of magnetic resonance imaging (MRI)-guided localizations with modified embolization coils for exclusively MRI-detected suspicious breast lesions.

MATERIALS AND METHODS

We performed 131 MRI-guided preoperative localizations in 105 patients with exclusively MRI-detected breast lesions. Contrast-enhanced, T1-weighted, 3-dimensional gradient echo sequences were used for imaging. Breast fixation and needle guidance were achieved by a perforated plate. Lesion localization was performed with a modified embolization coil. The distance between coil and lesion was measured. Results of specimen radiography and histopathology were analyzed.

RESULTS

Thirty-four of 131 lesions (26%) were malignant. Lesion localization and excision was successful in all patients. The mean distance between the coil and the lesion was 0.5 mm (+/-1.7 mm standard deviation).

CONCLUSIONS

Exact MRI-guided preoperative localization of exclusively MRI-detected breast lesions by using a modified embolization coil is feasible with excellent precision. Advantages over wire localization procedures are the possibility of specimen x-ray and the independence from time and place of operation.

Interventional and intraoperative MR: review and update of techniques and clinical experience

The concept of interventional magnetic resonance imaging (MRI) is based on the integration of diagnostic and therapeutic procedures, favored by the combination of the excellent morphological and functional imaging characteristics of MRI. The spectrum of MRI-assisted interventions ranges from biopsies and intraoperative guidance to thermal ablation modalities and vascular interventions. The most relevant recently published experimental and clinical results are discussed. In the future, interventional MRI is expected to play an important role in interventional radiology, minimal invasive therapy and guidance of surgical procedures. However, the associated high costs require a careful evaluation of its potentials in order to ensure cost-effective medical care.

Interventionelle MR-Mammographie: Manipulatorgestützte Biopsie und interstitielle Lasertherapie von Tumoren der weiblichen Brust

The present study investigated the clinical application of magnetic resonance (MR)-guided breast interventions, such as manipulator-assisted large core breast biopsy (LCBB) inside a 1.5 T whole-body magnet and MR-guided interstitial laser therapy (ILT). Sixteen patients underwent LCBB and 1 additional patient underwent 4 sessions of ILT of a recurrent undifferentiated lymph node metastasis in the axilla using a Nd-YAG laser (1064 nm). Temperature changes of the tumor tissue during ILT were monitored using phase images of a gradient echo sequence (GRE) (TR/TE/FA = 25/12/30). In 5 patients the biopsy findings were histopathologically confirmed after open surgery. In 3 patients, the biopsy missed one tubular and one ductal carcinoma; one invasive carcinoma was underestimated. Eight patients with benign findings are still in the follow-up period. The heating zone during ILT was well delineated on subtracted phase images. No severe adverse events were observed with LCBB or ILT. MR-guided breast biopsies are feasible with the manipulator system inside a whole-body 1.5 Tesla MR scanner. GRE information is suitable for therapy monitoring during ILT within the tumor. Further studies are necessary to evaluate the accuracy of the manipulator system and the efficacy of ILT in the treatment of breast lesions.