乳腺磁共振在乳腺癌诊断治疗中的运用

乳腺MRI具有很好的软组织分辨率和无射线辐射等优点,对乳腺癌的早期诊断和局部分期明显优于乳腺X线摄影和超声检查。随着乳腺癌个体化、规范化综合治疗理念的推广,乳腺MRI在综合治疗中的作用日益受到重视,伴随对乳腺MRI临床应用的开展和研究的深入,其在乳腺癌分期中的评估、保乳手术病例术前的筛选、腋窝淋巴结转移原发不明者的诊断、新辅助化疗(neoadjuvant chemotherapy, NAC)的疗效评估、随访监测中的应用价值也得到了很好的评估。同时,乳腺MRI对肿瘤范围的客观准确的评估也是正确选择治疗方式的依据。     

Breast conservation treatment for patients presenting with axillary lymphadenopathy from presumed primary breast cancer: the role of breast magnetic resonance imaging for staging

Three female patients presented with malignant axillary lymphadenopathy presumed to be from primary breast cancer. No evidence of primary cancer was found in the breast on either mammography or breast magnetic resonance imaging (MRI). All 3 patients underwent axillary lymph node dissection and systemic chemotherapy followed by radiation therapy to the breast and regional lymph nodes. Two patients remain relapse free with a follow-up of 3.7 years each. The third patient achieved locoregional control in the ipsilateral breast and regional lymph nodes but relapsed in the contralateral axilla. These 3 cases illustrate the potential for breast conservation treatment for patients presenting with axillary adenopathy from a presumed primary breast cancer but without either mammographic or breast MRI findings.     

Effect of breast magnetic resonance imaging on the clinical management of women with early-stage breast carcinoma.

PURPOSE: To determine the impact of breast magnetic resonance imaging (MRI) on the clinical management of patients with early-stage breast cancer. PATIENTS AND METHODS: A review was performed of the records of 207 women with early-stage breast cancer (including five women with bilateral disease) who underwent breast MRI during work-up for breast conservation treatment. All patients presented with clinical stage 0, I, or II disease. For each patient, a determination was made whether the breast MRI affected the clinical management, and if so, whether the patient was well served by the change in management. RESULTS: The MRI findings affected the clinical management in 43 cases (20% of 212 breast cancers). Based on the pathology findings and the overall clinical course for each case, the breast MRI was judged to have had a strongly favorable effect on management in 18 cases (8%), a somewhat favorable effect in six cases (3%), an uncertain effect in five cases (2%), a somewhat unfavorable effect in 11 cases (5%), and a strongly unfavorable effect in three cases (1%). The effect of MRI was not significantly different for invasive carcinoma compared with ductal carcinoma-in-situ (all P > or =.27). However, the effect of MRI was significantly greater when the MRI was performed before an excisional biopsy (P =.0011) or for larger tumors (P =.0089). CONCLUSIONS: Breast MRI alters the clinical management for a sizable fraction of women with early-stage breast cancer and appears to offer clinically useful information for determining optimal local treatment.     

Hypofractionation with no boost after breast conservation in early-stage breast cancer patients

The aim of this study was to evaluate local control, survival and toxicity profile of a consecutive cohort of early-stage breast cancer (EBC) patients treated with adjuvant hypofractionated radiotherapy (HF) with no boost delivered to the lumpectomy cavity, after breast-conserving surgery (BCS). Between 2005 and 2015, a total of 493 women affected with EBC were treated with HF (46 Gy/20 fractions or 40.05 Gy/15 fractions) to the whole breast without boost to tumor bed, because of age and/or favorable tumor characteristics. The primary endpoint was 5-year actuarial local control (LC); secondary endpoints included survival, toxicity profile and cosmesis. Median follow-up was 57 months (range 6–124). Actuarial 5-year overall, cancer-specific, disease-free survival and LC were 96.3, 98.9, 97.8 and 98.6 %, respectively. On multivariate analysis, tumor stage (T1 vs. T2) and hormonal status (positive vs. negative estrogen receptors) were significantly correlated with LC. Only 2 % of patients experienced ≥G3 acute skin toxicity. Late toxicity was mild with only 1 case of G3 fibrosis. Most of the patients (95 %) had good–excellent cosmetic results. HF to the whole breast with no boost delivered to the tumor bed is a safe and effective option for a population of low-risk breast cancer patients after BCS, with excellent 5-year LC, mild toxicity profile and promising cosmetic outcome. A subgroup of patients with larger tumors and/or with no estrogen receptor expression may potentially benefit from treatment intensification with a boost dose to the lumpectomy cavity.     

动态增强磁共振联合弥散加权成像在新辅助化疗乳腺癌患者术前评估中的作用

目的 评价动态增强磁共振联合弥散加权成像在新辅助化疗乳腺癌患者术前评估中的作用.方法 30位经巴德针（Bard magnum biopsy needIes）穿刺活检确诊为乳腺癌的患者,临床分期ⅡA～ⅢC,均予以新辅助化疗（含紫杉醇类和/或蒽环类）2～5周期.所有患者手术前均行磁共振成像（MRI）、B超及临床检查,以术后病理检查结果为金标准,3种方法所测出肿块的最长径与最短径分别与之相对比,评价MRI在评估肿块大小范围上的准确性及在判断肿块化疗后形态改变上的作用,并且评估MRI在判断腋窝淋巴结转移方面的作用.结果 MRI检查测出的肿块最长径与病理检查测出的最长径的关联性最高（r=0.840,P＜0.05）,B超检查与病理检查呈中度关联（r=0.635,P＜0.05）,临床检查与病理检查的关联性最低（r=0.583,P＜0.05）;最短径得出的结果与之类似.新辅助化疗后残留肿块在MRI上呈现两种形态：20%为多发结节型及树枝型,80%为单发结节型.MRI在腋窝淋巴结是否转移的判断上,敏感度为45.5%,特异度为50.0%,准确度为46.7%.根据最后动态增强磁共振联合弥散加权成像的结果,有5例患者改变了原订的手术方案.结论 动态增强磁共振联合弥散加权成像在乳腺癌新辅助化疗后能更好评估残留癌的范围及形态,帮助外科医师更好地进行术前评估,更好地选择手术方式和确定手术切缘,但其在判断腋窝淋巴结状态的价值有待进一步探讨.     

Impact of concurrent versus sequential tamoxifen with radiation therapy in early-stage breast cancer patients undergoing breast conservation treatment.

PURPOSE: To assess the impact of sequencing of tamoxifen and radiation therapy (RT) on outcomes in early-stage breast cancer. PATIENTS AND METHODS: This retrospective study evaluates the effect of the sequence of tamoxifen with RT on outcomes in stage I to II breast cancer patients who underwent breast-conservation treatment (BCT) and received adjuvant tamoxifen, with or without adjuvant chemotherapy. Patients were grouped as concurrent (tamoxifen given during RT followed by continued tamoxifen; 174 patients) and sequential (RT followed by tamoxifen; 104 patients). RESULTS: Median follow-up after RT was 8.6 years for both groups. The pathologic T and N stage, race, estrogen and progesterone status, number of positive nodes, and RT were comparable between the two groups (all P >/= .08). More women age 49 years or younger and women who received chemotherapy were in the sequential group than the concurrent group (6% and 25%, respectively; P < .0001). The sequence of tamoxifen therapy did not influence 10-year local recurrence rates (sequential, 7%; concurrent, 3%; P = .52), overall survival (sequential, 86%; concurrent, 81%; P = .64), or relapse-free survival (sequential, 76%; concurrent, 85%; P = .35). When adjusting age and chemotherapy use in the multivariable Cox model, hazard ratios comparing sequential versus concurrent tamoxifen therapy were 1.56 (95% CI, 0.87 to 2.79), 1.23 (95% CI, 0.63 to 2.41), and 1.22 (95% CI, 0.33 to 4.49) for the overall survival, relapse-free survival, and local recurrence, respectively. CONCLUSION: The therapeutic regimens of tamoxifen given concurrently or sequentially with RT both appear to be reasonable options for patients treated with BCT.     

Cardiac morbidity and mortality after breast conservation treatment in patients with early-stage breast cancer and preexisting cardiac disease

BackgroundThis study was undertaken to determine the risk of late cardiac morbidity and mortality in patients with preexisting cardiac disease treated with contemporary radiation techniques for early-stage breast cancer.Patients and MethodsMedical records were reviewed for 41 patients with early-stage breast cancer and a history of myocardial infarction, congestive heart failure (CHF), and/or coronary artery disease before radiation therapy. Data were recorded on baseline cardiac disease and tumor characteristics, cardiac morbidity during and after treatment, and survival status of each patient. Patients were stratified for right-versus left-sided breast cancer and compared.ResultsThere was no significant difference in overall survival (OS) between the right-and left-sided groups (log-rank test; P = .19). The left-sided group had a higher incidence of cardiac deaths (right side, 2 of 26 [9%]; left side, 4 of 15 [27%]; hazard ratio, 4.2; P = .08) 10 years after treatment, including deaths secondary to myocardial infarction, CHF, or coronary artery disease. On the other hand, the right-sided group had a higher proportion of deaths secondary to breast cancer (right, 8 of 26 [31%]; left, 2 of 15 [13%]) and non–breast cancer/noncardiac causes (right, 7 of 26 [27%]; left, 1 of 15 [7%]).ConclusionAlthough OS was similar in both groups, radiation was associated with a higher incidence of cardiac death in patients with left-sided breast cancer. Efforts should be made to minimize cardiac exposure and also to promote more vigilant risk factor modification in this group of women.     

Complementary role of adjunctive breast magnetic resonance imaging and scintimammography in patients of all ages undergoing breast cancer surgery

The aims of this study were to assess breast MRI and scintimammography (SMM) for the detection of breast cancer, and to determine any complementary role of these tests to each other and conventional imaging. Seventy‐two patients (age 35–81 years) with a suspicious breast mass were investigated by mammography, breast ultrasound, breast MRI and SMM before undergoing surgical excision of the breast mass. Sensitivity, specificity and area under receiver operator characteristic curves were calculated for each test. Of the 72 patients, there were 66 proven malignant tumours, including two patients with bilateral breast cancer. When comparing the diagnostic sensitivity of breast MRI and SMM for lesion size, both tests showed higher sensitivities for lesions >25 mm in size, particularly for SMM. When these tests were compared for patient age, patients less than 51 years showed higher sensitivities for both tests. This was statistically significant for breast MRI. The overall respective diagnostic sensitivities for mammography, mammography with breast ultrasound, breast MRI and SMM were 56, 67, 86 and 85%. The differences were significant between mammography, mammography/ultrasound and both breast MRI and SMM. Breast MRI and SMM offer incremental diagnostic advantage in the diagnosis of breast cancer. Although improved diagnostic accuracy is seen in patients of all ages, those patients less than 51 years of age receive the greatest diagnostic benefit.     

Preoperative breast magnetic resonance imaging in early breast cancer

BACKGROUND:

Accelerated partial breast irradiation (APBI) of patients with early breast cancer is being investigated on a multi‐institutional protocol National Surgical Adjuvant Breast and Bowel Project (NSABP) B‐39/RTOG 0413. Breast magnetic resonance imaging (MRI) is more sensitive than mammography (MG) and may aid in selection of patients appropriate for PBI.

METHODS:

Patients with newly diagnosed breast cancer or ductal carcinoma in situ (DCIS) routinely undergo contrast‐enhanced, bilateral breast MRI at the Cleveland Clinic. We retrospectively reviewed the medical records of all early‐stage breast cancer patients who had a breast MRI, MG, and surgical pathology data at our institution between June of 2005 and December of 2006. Any suspicious lesions identified on MRI were further evaluated by targeted ultrasound ± biopsy.

RESULTS:

A total of 260 patients met eligibility criteria for NSABP B‐39/RTOG 0413 by MG, physical exam, and surgical pathology. The median age was 57 years. DCIS was present in 63 patients, and invasive breast cancer was found in 197 patients. MRI identified suspicious lesions in 35 ipsilateral breasts (13%) and in 16 contralateral breasts (6%). Mammographically occult, synchronous ipsilateral foci were found by MRI in 11 patients (4.2%), and in the contralateral breast in 4 patients (1.5%). By univariate analysis, lobular histology (infiltrating lobular carcinoma [ILC]), pathologic T2, and American Joint Committee on Cancer stage II were significantly associated with additional ipsilateral disease. Of patients with ILC histology, 18% had ipsilateral secondary cancers or DCIS, compared with 3% in the remainder of histologic subtypes (P = .004). No patient older than 70 years had synchronous cancers or DCIS detected by MRI.

CONCLUSIONS:

Breast MRI identified synchronous mammographically occult foci in 5.8% of early breast cancer patients who would otherwise be candidates for APBI. Cancer 2009. © 2009 American Cancer Society.     

The evaluation of human breast lesions with magnetic resonance imaging and proton magnetic resonance spectroscopy

Purpose. MR spectroscopy (MRS) assists in lesion characterization and diagnosis when combined with magnetic resonance imaging (MRI). Cancerous lesions demonstrate elevated composite choline levels arising from increased cellular proliferation. Our study investigated if MR spectroscopy of the breast would be useful for characterizing benign and malignant lesions. Materials and methods. Single voxel proton MR spectroscopy (MRS) was acquired as part of an MR imaging protocol in 38 patients referred upon surgical consultation. The MR spectra were read independently in a blinded fashion without the MR images by three spectroscopists. The MRI exam was interpreted in two settings: (a) as a clinical exam with detailed histories and results from previous imaging studies such as mammography or ultrasound included and (b) as a blinded study without prior histories or imaging results. Results. Elevated choline levels were demonstrated by MRS in 19 of the 23 confirmed cancer patients. The sensitivity and specificity for determining malignancy from benign breast disease with MRS alone were 83 and 87%, respectively, while a blinded MRI review reported 95 and 86%, respectively. Conclusions. Proton MR spectroscopy provides a noninvasive, biochemical measure of metabolism. The technique can be performed in less than 10min as part of an MRI examination. MRI in combination with MRS may improve the specificity of breast MR and thereby, influence patient treatment options. This may be particularly true with less experienced breast MRI readers. In exams where MRI and MRS agree, the additional confidence measure provided by MRS may influence the course of treatment.     

Role of magnetic resonance imaging in the pre and postchemotherapy evaluation in locally advanced breast carcinoma

The study was carried out to evaluate the response to preoperative chemotherapy of locally advanced breast cancer with MRI. The series included 45 women with locally advanced breast cancer who underwent MRI before and after neoadjuvant chemotherapy. Based on the volume of residual disease, the response to chemotherapy was classified as: complete response, partial response, minor response, no change and disease progression. Responses to neoadjuvant chemotherapy were compared to MRI findings and to prognostic factors. Based on MRI findings 8 patients were assigned to the complete response group, 16 to the partial response group, 11 to the minor response group, 9 to the no change group and 1 patient to the disease progression group. MRI showed 90.2% sensitivity, 100% specificity and 91.1% accuracy. The correlation between MRI findings and prognostic factors may be useful to predict cancer aggressiveness and to understand the natural history of different breast carcinomas.     

Role of magnetic resonance imaging in inflammatory carcinoma of the breast

The study was carried out to assess the role of magnetic resonance imaging in the inflammatory carcinoma of the breast. 15 female patients with a clinical diffuse inflammatory process in the breast underwent mammography, sonography and dynamic magnetic resonance imaging. All inflammatory carcinomas showed a patch enhancement pattern and in 7/10 there were some areas of focal enhancement. A patch enhancement was observed in 2/5 cases of mastitis while in the other 3 cases nodular focal areas with peripheral enhancement were seen. The dynamic curves were always of wash-out type. Maximum signal intensity value was over 70% in 3/5 cases of mastitis and in 9/10 cases of inflammatory carcinoma. Our results suggest that the role of magnetic resonance imaging in the characterization of inflammatory processes of the breast is nonspecific, while it may be useful in the follow-up of mastitis.     

Role of MRI (magnetic resonance imaging) versus conventional imaging for breast cancer presurgical staging in young women or with dense breast

Aims

The role of magnetic resonance imaging (MRI) in the local staging of breast cancer is currently uncertain. The purpose of this prospective study is to evaluate the accuracy of preoperative MRI compared to conventional imaging in detecting breast cancer and the effect of preoperative MRI on the surgical treatment in a subgroup of women with dense breasts, young age, invasive lobular cancer (ILC) or multiple lesions.

Methods

Between January 2006 and October 2007, 91 patients with newly diagnosed breast cancer underwent preoperative clinical breast examination, mammography, bilateral breast ultrasonography and high-resolution breast MRI. All patients had histologically verified breast cancer. The imaging techniques were compared using the final pathological report as gold standard.

Results

The sensitivity of MRI for the main lesion was 98.9%, while for multiple lesions sensitivity was 90.7% and specificity 85.4%. After preoperative MRI, 13 patients (14.3%) underwent additional fine needle/core biopsies, 9 of whom had specimen positive for cancer. Preoperative MRI changed the surgical plan in 26 patients: in 19.8% of the cases breast conservative surgery was converted to mastectomy and in 7.7% of the patients a wider excision was performed. At a mean follow-up of 48 months, 2 local recurrences occurred (local failure rate = 2.5%).

Conclusions

Enhanced sensitivity of breast MRI may change the surgical approach, by increasing mastectomy rate or suggesting the need of wider local excision. MRI can play an important role in preoperative planning if used in selected patients with high risk of multifocal/multicentric lesions. However, the histologic confirmation of all suspicious findings detected by MRI is mandatory prior to definite surgery.     

New magnetic resonance imaging techniques for the detection of breast cancer

Summary The importance of contrast agents in enhancing diagnoses from magnetic resonance images has been established in numerous cases. However, the development of a potent tissue-specific contrast agent, as a sensitive probe for early detection and investigation of the physiological characteristics of a tumor, has not yet been realized in MR imaging (MRI). In nuclear scintigraphy the technique has been demonstrated; however, the poor spacial resolution inherent to the modality and the substantial dose of radioactivity administered to the patient has hindered its widespread use. This article will review the different classes of contrast agents in MRI, with special focus on the strategies involved in the development of targeted tissue-specific MRI contrast agents for the early detection of breast cancer. The features of a new class of contrast agents for targeted MR imaging will be described. Gadolinium-containing melanin polymers (GMP's) have been synthesized as MR contrast agents in our laboratory. These GMP's demonstrate significantly higher relaxivities than any other paramagnetic contrast agents reported; consequently, they are extremely effective contrast enhancing, imaging agents by themselves. The successful coupling of these potent GMP's to a monoclonal antibody specific for breast carcinoma, the 323/A3 monoclonal antibody, suggests thatin vivo tissue-specific MR imaging, at the receptor level, will become feasible in the near future.     

Role of resection margins in patients treated with breast conservation surgery

BACKGROUND: After breast conservation therapy (BCT), margin status is routinely evaluated to select patients who need reexcision. The aim of this study was to investigate how margin status and other clinicopathologic factors correlate with the presence of residual tumor at reexcision. METHODS: A series of 431 breast cancer patients who underwent BCT followed by reexcision were considered because they had positive or close (< or =3 mm) margins. At univariate and multivariate analysis the frequency of residual tumor in the reexcision specimens was associated with the status and width of resection margins and with a series of other clinicopathologic factors. RESULTS: Of the 382 evaluable patients, 253 had positive and 129 close margins. Residual tumor was found at reexcision in 51.8% positive-margin patients and 34.1% close-margin patients (P = .001). In the latter group tumor-margin distance (range, 0.08 to 3 mm) was not associated with the incidence of residual tumor (P = .134). On univariate analysis age < or =45 years (P = .006), intraductal histotype (P = .005), size > 2 cm (P = .010), positive axillary nodes (P = .031), and timing of reexcision (P = .044) were significantly associated with a higher frequency of residual tumor. All these factors, except tumor size, maintained a significant predictive value on multivariate analysis. CONCLUSIONS: In the presence of positive margins, relevant residual disease cannot be ruled out and further surgery is indicated. Close margins do not mandate reexcision because they may indicate either that the tumor has been radically excised or the presence of residual foci of a multifocal tumor, which are usually effectively treated by radiotherapy.     

The accuracy of magnetic resonance imaging and ultrasound in evaluating the size of early-stage breast neoplasms

Objective Breast cancer is the most frequently diagnosed cancer in women. Accurate evaluation of the size and extent of the tumor is crucial in selecting a suitable surgical method for patients with breast cancer. Both overestimation and underestimation have important adverse effects on patient care. This study aimed to evaluate the accuracy of breast magnetic resonance imaging（MRI） and ultrasound（US） examination for measuring the size and extent of early-stage breast neoplasms.Methods The longest diameter of breast tumors in patients with T_1–2N_0–1M₀ invasive breast cancer preparing for breast-conserving surgery（BCS） was measured preoperatively by using both MRI and US and their accuracy was compared with that of postoperative pathologic examination. If the diameter difference was within 2 mm, it was considered to be consistent with pathologic examination.Results A total of 36 patients were imaged using both MRI and US. The mean longest diameter of the tumors on MRI, US, and postoperative pathologic examination was 20.86 mm ± 4.09 mm（range: 11–27 mm）, 16.14 mm ± 4.91 mm（range: 6–26 mm）, and 18.36 mm ± 3.88 mm（range: 9–24 mm）. US examination underestimated the size of the tumor compared to that determined using pathologic examination（t = 3.49, P < 0.01）, while MRI overestimated it（t =-6.35, P < 0.01）. The linear correlation coefficients between the image measurements and pathologic tumor size were r = 0.826（P < 0.01） for MRI and r = 0.645（P < 0.01） for US. The rate of consistency of MRI and US compared to that with pathologic examination was 88.89% and 80.65%, respectively, and there was no statistically significant difference between them（χ² = 0.80, P > 0.05）.Conclusion MRI and US are both effective methods to assess the size of breast tumors, and they maintain good consistency with pathologic examination. MRI has a better correlation with pathology. However, we should be careful about the risk of inaccurate size estimation.     

Response evaluation of bone metastases in breast cancer: value of magnetic resonance imaging

The clinical utility of magnetic resonance imaging (MRI) in judging therapeutic response of bone metastases was evaluated in 18 patients with advanced breast cancer. Treatment efficacy was assessed by MRI and conventional methods such as plain radiograph, bone scan, pain and analgesic scale, and serum CA15-3. The response by MRI was evaluated mainly on T1-weighted sequences by measuring the volume of the bone lesion and soft tissue component. The patient was assumed to be a conventional responder if a complete or partial response was observed in any of the conventional methods described above. Response was most concordant between plain radiographs and MRI findings (91%, 10/11, 95% confidence interval [CI]: 58.7-99.8). The rate of concordance was 61% (11/18, 95% CI 35.8-82.7) for all conventional methods and MRI. MRI revealed response in four patients in whom progressive disease was observed by bone scan and the marker response was not measurable. This pilot study suggests that posttherapy evaluation with MRI may provide useful clinical information in breast cancer patients with bone metastases and may be a valuable adjunct to conventional methods with conflicting results.     

Meta-analysis of pre-operative magnetic resonance imaging (MRI) and surgical treatment for breast cancer

Background

As mastectomy rates increase and overall survival for early breast cancer improves, a better understanding of the long-term consequences of mastectomy is needed. We sought to explore the correlation of specific mastectomy type with the Female Sexual Function Index (FSFI), body image satisfaction, and the reconstructed breast’s role in intimacy.

Methods

This study is a secondary analysis of a cross-sectional survey including a retrospective chart review. Patients at least one year from primary surgery were invited to complete the survey between 2012 and 2014. Baseline characteristics and survey responses were compared between three mastectomy groups: total/modified radical (TMRM), skin-sparing (SSM), and nipple-sparing (NSM). All patients underwent reconstruction.

Results

Of 453 invited, 268 (59%) completed the survey. Sixty underwent mastectomy with reconstruction: 16 (27%) TMRM, 36 (60%) SSM, and 8 (13%) NSM. There were no significant differences in median total FSFI scores between groups, yet median FSFI scores for the NSM group indicated sexual dysfunction. After adjusting for receipt of chemotherapy and/or radiation, NSM had the lowest median desire score. There was a trend for the NSM group to be the least satisfied with postoperative appearance, but also more likely to report that the chest was “often” caressed during intimacy. However, nearly 40% of the NSM group reported that caress of the reconstructed breast was unpleasant.

Conclusion

NSM offers patients the greatest opportunity for preservation of their native skin envelope and potentially enhanced cosmetic outcome, but our results did not demonstrate superior sexual function or body image outcomes in this group. By highlighting surgical consequences of mastectomy preoperatively, surgeons may better set realistic patient expectations regarding both aesthetic and functional outcomes after breast cancer surgery. With clearer expectations, patients will have a better opportunity for improved surgical decision-making.

     

Contrast-enhanced magnetic resonance imaging of the breast.

Contrast-enhanced magnetic resonance imaging (MRI) of 28 patients with known breast tumors was compared with clinical findings and histopathology, and for 12 of the patients also with mammography. The dynamic measurements performed in 18 patients showed that signal intensity in gradient echo (FFE) images increased rapidly in malignant tumors after contrast injection and reached a plateau level at 1-3 min postcontrast. Fibroadenomas showed slower contrast enhancement continuing throughout the whole examination period of 10 min. The most enhancing parts of the tumors were selected for intensity measurements. The differentiation between malignant and benign tumors in dynamic contrast-enhanced MRI was in accordance with the histopathological findings in all cases. The tumor diameter as measured by MRI showed very good agreement with the size of the tumor specimens. Comparison of tumor size measurements in mammography and MRI showed that MRI had the most accurate correlation to the measured size of the tumor specimens.