MR-guided minimally invasive procedures.

This article outlines the integration of breast MR imaging minimally invasive therapy for breast tumors. Technical obstacles discussed include accurate determination of margins, DCIS, and localization methods. Treatment methods such as cryotherapy, interstitial hyperthermia, and focused ultrasound are discussed. Other subjects include the amount of minimally-invasive therapy performed to date and the ethical dilemma of clinical trials.

Integration of breast MRI in clinical trials.

Clinical trials are the mechanism for implementing new treatment methods into clinical practice. A number of organizations have been developed to facilitate the initiation, implementation, and data analysis for clinical trials. Imaging is important for patient selection and establishment of endpoints, yet imaging expertise has been underrepresented in most clinical trial groups. The integration of breast MRI in clinical trials is an important step toward the establishment of this method of imaging in routine practice. In addition, these data will be important in justifying the expense of MRI to payer organizations. The potential roles of breast MRI in clinical trials are reviewed. These breast MRI applications are linked with some of the studies that are under development. It is important for the MRI community to be aware of the importance of clinical trials in the future clinical establishment of breast MRI. J. Magn. Reson. Imaging 2001;13:830-836.

Efficacy and safety of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. Multicenter phase III clinical trials. Efficacy of early imaging.

The efficacy of contrast-enhanced magnetic resonance imaging (MRI) for detecting and characterizing, or excluding, hepatic masses was assessed in 404 patients, following the intravenous administration of mangafodipir trisodium (MnDPDP) injection, a hepatic MRI contrast agent. An initial contrast-enhanced computed tomography (CT) examination was followed by unenhanced MRI, injection of MnDPDP (5 micromol/kg IV), and enhanced MRI at 15 minutes post injection. Agreement of the radiologic diagnoses with the patients' final diagnoses was higher for enhanced MRI and for the combined unenhanced and enhanced MRI evaluations than for unenhanced MRI alone or enhanced CT using the clinical diagnosis as the gold standard. Mangafodipir-enhanced MRI uniquely provided additional diagnostic information in 48% of the patients, and patient management was consequently altered in 6% of the patients. MnDPDP-enhanced MRI was comparable or superior to unenhanced MRI and enhanced CT for the detection, classification, and diagnosis of focal liver lesions in patients with known or suspected focal liver disease.

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety).

The short-term safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast-enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 micromol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection-associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%) and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short-term risks from exposure to MnDPDP.

Role of breast magnetic resonance imaging in determining breast as a source of unknown metastatic lymphadenopathy.

BACKGROUND: Occult primary breast cancer (OPBC) represents less than 1% of breast cancer. In only a third of cases, mammography identifies a primary tumor. We hypothesized that rotating delivery of excitation off-resonance breast magnetic resonance imaging (MRI) would identify or exclude the breast as a primary site in patients with OPBC. METHODS: In a retrospective review, 10 patients were identified with OPBC in which MRI was performed. Malignant appearing lesions were correlated with histopathologic findings at biopsy or surgery. RESULTS: MRI identified the primary site in 8 of 10 cases as breast (80%), and excluded it in 2 cases. The extent of disease and location was accurately predicted when compared with histopathologic specimen. CONCLUSIONS: As we continue to focus on a cure of early breast cancer, it is imperative that diagnostic images become more sensitive and specific. MRI accurately predicted OPBC in this subset of patients.

Integration of breast magnetic resonance imaging with breast cancer treatment.

High-contrast, high-resolution breast magnetic resonance imaging (MRI) is a highly accurate method for determining the extent of breast cancer. This information can be used to improve therapy by better defining the extent of surgery needed, coordinating additional surgery if the initial surgery results in positive pathological margins, and determining the effectiveness and extent of residual disease following nonsurgical therapy. The use of stereotaxic biopsy and localization is an essential component for extending the use of breast MRI in therapeutic applications. The clinical value of therapeutic management with breast MRI information is expected to result in commercially available tools in the near future.

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.

A physics-based coordinate transformation for 3-D image matching.

Many image matching schemes are based on mapping coordinate locations, such as the locations of landmarks, in one image to corresponding locations in a second image. A new approach to this mapping (coordinate transformation), called the elastic body spline (EBS), is described. The spline is based on a physical model of a homogeneous, isotropic three-dimensional (3-D) elastic body. The model can approximate the way that some physical objects deform. The EBS as well as the affine transformation, the thin plate spline [1], [2] and the volume spline [3] are used to match 3-D magnetic resonance images (MRI's) of the breast that are used in the diagnosis and evaluation of breast cancer. These coordinate transformations are evaluated with different types of deformations and different numbers of corresponding (paired) coordinate locations. In all but one of the cases considered, using the EBS yields more similar images than the other methods.

Detection with MR imaging of residual tumor in the breast soon after surgery.

OBJECTIVE: Difficulties in the preoperative assessment of tumor size and extent result in a positive pathologic margin in up to 70% of patients undergoing breast conservation surgery. Although positive margins usually require reexcision, the location and extent of surgery required are often difficult to establish by current imaging techniques. We investigated the accuracy of three-dimensional rotating delivery of excitation off resonance (3D RODEO) MR imaging of the breast in revealing the presence and extent of residual tumor within the breast soon after surgery. MATERIALS AND METHODS: Nineteen patients who had undergone lumpectomy or excisional biopsy were evaluated with contrast-enhanced 3D RODEO MR imaging of the breast within 10 months after surgery. The MR imaging results were correlated with serial-sectioned mastectomy or partial mastectomy specimens from 18 patients and with a clinical and mammographic follow-up examination in one patient. RESULTS: We found that 3D RODEO MR imaging accurately revealed the presence or absence and the location and extent of recurrent tumor in 15 of the 18 patients who had pathologic confirmation. Of the three MR imaging-pathology mismatches, two had irregular or nodular enhancement that corresponded to microabscesses. The third mismatch showed multicentric disease on MR imaging but only single-quadrant lobular carcinoma at pathologic examination. Our 19th patient showed no evidence of recurrent tumor on MR imaging or at 2-year follow-up clinical and mammographic examinations. CONCLUSION: MR imaging with 3D RODEO technique correctly revealed the presence or absence, the location, and the extent of recurrent tumor in 84% of patients who had recently undergone breast surgery.

MR imaging in the management before surgery of lobular carcinoma of the breast: correlation with pathology.

OBJECTIVE: Our objective was to investigate the use of MR imaging in preoperative staging and characterization of lobular carcinoma. MATERIALS AND METHODS: MR imaging studies and mammographic studies in 20 patients with infiltrating lobular carcinoma were evaluated and correlated with pathology findings on serially sectioned tissue. The MR images and mammograms were reviewed retrospectively by three independent examiners unaware of the clinical, imaging, and pathology findings. RESULTS: The extent of disease found pathologically correlated with that predicted by MR imaging studies in 85% of patients, compared with a 32% correlation (p < .0001) with mammographic studies. Interobserver agreement on lesion morphology and extent of disease was higher for MR imaging (91% and 100%, respectively) than for mammography (64% and 91%, respectively). The retrospective MR readings did not differ from the prospective reports. No false-positive lymphadenopathy was interpreted on MR imaging. Lymph nodes having metastatic lobular carcinoma on the pathology examination were missed on MR imaging in four patients. CONCLUSION: MR imaging is significantly more accurate than mammography in determining the extent of disease and characterizing the morphology of infiltrating lobular carcinoma. MR imaging may play a role in preoperative planning, especially when breast conservation is being considered.

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.

Three-dimensional RODEO breast MR imaging of lesions containing ductal carcinoma in situ.

PURPOSE: To assess whether rotating delivery of excitation off resonance (RODEO) breast magnetic resonance (MR) imaging can help detect ductal carcinoma in situ (DCIS) lesions, determine tumor extent, and differentiate pure DCIS from DCIS with an invasive component. MATERIALS AND METHODS: Twenty-two patients with DCIS lesions were evaluated with three-dimensional RODEO MR imaging. Nineteen patients had available mammograms for review. RESULTS: MR imaging enabled detection of all 22 cases of DCIS, DCIS with microinvasion, or invasive ductal carcinoma with extensive intraductal component. A clumped enhancement pattern was seen on MR images in all cases of pure DCIS. Spiculated enhancement was seen in four of six (67%) patients who had DCIS with microinvasion and in nine of 11 (82%) who had invasive ductal carcinoma with extensive intraductal component. RODEO MR imaging enabled accurate determination of tumor extent in 21 of 22 (95%) patients. Mammography depicted 18 of 19 DCIS lesions. No mammographic feature helped differentiate pure DCIS from DCIS with microinvasion. Mammography enabled accurate determination of tumor extent in 14 of 19 (74%) patients. CONCLUSION: Three-dimensional RODEO MR imaging can be an adjunct to mammography because of its ability to enable better determination of tumor extent and differentiation of pure DCIS from DCIS with an invasive component.

Evaluation of neoadjuvant chemotherapeutic response of locally advanced breast cancer by magnetic resonance imaging.

BACKGROUND: The implementation of new treatment protocols for locally advanced breast cancer is currently limited by inaccurate evaluation of response to neoadjuvant chemotherapy. A recently developed dedicated breast magnetic resonance imaging (MRI) method (RODEO MRI) was evaluated as a tool for determining tumor response and extent of residual disease after neoadjuvant chemotherapy. METHODS: Thirty-nine patients with Stage II, III, or IV breast carcinoma were prospectively evaluated prior to and following neoadjuvant chemotherapy by MRI, physical examination, and mammography. Assessment of response determined by the three methods was compared. In addition, detailed pathologic correlation of residual disease was determined by serial sectioning of 31 mastectomy specimens from 30 patients. Nine patients had breast conservation, and were included in the response evaluation only. Estimates of tumor response were made by both surgical and medical oncologists. Independent interpretations of MRI studies without knowledge of clinical response were made by three radiologists. RESULTS: The surgical oncologists assessed complete response (CR), partial response (PR), and no response (NR) in 11, 22, and 7 cases, respectively. The medical oncologists assessed CR, PR, and NR in 12, 21, and 7 cases, respectively. The surgical and medical oncologists' clinical assessment of response agreed with the results of MRI in 52% and 55% of cases, respectively, and with each other in 30 of 40 cases (75%). Mammography correlated with MRI response in only 52% of cases. However, MRI accurately predicted the pathologic determination of residual disease in 30 of 31 cases (97%). There was no disagreement in the assessments of residual disease or response among the three radiologists. CONCLUSIONS: RODEO breast MRI accurately estimates residual disease after induction chemotherapy. It assesses response to neoadjuvant chemotherapy better than traditional methods of physical examination or mammography. The information obtained from this MRI technique may be used as an objective tool during clinical trials, and to select patients better for breast conservation after neoadjuvant chemotherapy for locally advanced disease.

MRI efficacy and effectiveness research: who needs it and who pays for it?

Health care reform has made quality efficacy research in MRI important to an increasing number of audiences. Historically, the deficit of quality outcomes research in MRI was due to difficulties in study design, lack of funding, disincentives for researches and funding sources, and poor coordination. These issues would be best addressed by the formation of an MRI implementation group that would coordinate funding, planning, and dissemination of the outcomes research efforts.