Targeted ultrasound for MR-detected lesions in breast cancer patients.

OBJECTIVE: To investigate the usefulness of targeted ultrasound (US) in the identification of additional suspicious lesions found by magnetic resonance (MR) imaging in breast cancer patients and the changes in treatment based on the identification of the lesions by the use of targeted US. MATERIALS AND METHODS: One-hundred forty nine patients who underwent breast MR imaging for a preoperative evaluation of breast cancer between January 2002 and July 2004 were included in the study. We searched all cases for any additional lesions that were found initially by MR imaging and investigated the performance of targeted US in identifying the lesions. We also investigated their pathological outcomes and changes in treatment as a result of lesion identification. RESULTS: Of the 149 patients with breast cancer, additional suspicious lesions were detected with MR imaging in 62 patients (42%). Of the 69 additional lesions found in those 62 patients, 26 (38%) were confirmed as cancers by histology. Thirty-eight lesions in 31 patients were examined with targeted US and were histologically revealed as cancers in 18 (47%), high risk lesions in two (5%), benign lesions in 15 (39%), and unidentified lesions in three (8%). The cancer rate was statistically higher in lesions with a US correlate than in lesions without a US correlate (p = 0.028). Of 31 patients, the surgical plan was altered in 27 (87%). The use of targeted US justified a change in treatment for 22 patients (81%) and misled five patients (19%) into having an unnecessary surgical excision. CONCLUSION: Targeted US can play a useful role in the evaluation of additional suspicious lesions detected by MR imaging in breast cancer patients, but is limited in lesions without a US correlate.     

Real-time MRI navigated US: Role in diagnosis and guided biopsy of incidental breast lesions and axillary lymph nodes detected on breast MRI but not on second look US

Objectives

To prospectively evaluate the accuracy of real-time ultrasound combined with supine-MRI using volume navigation technique (RtMR-US) in diagnosis and biopsy of incidental breast lesions (ILSM) and axillary lymph nodes (LNSM) suspicious of malignancy on contrast enhanced magnetic resonance imaging (CE-MRI).

Materials and methods

Five hundred and seventy-seven women were examined using breast CE-MRI. Those with incidental breast lesions not identified after second-look ultrasound (US) were recruited for RtMR-US. Biopsy was performed in ILSM. Breast lesions were categorized with BI-RADS system and Fisher’ exact test. Axillary lymph nodes morphology was described. To assess efficacy of RtMR-US, diagnostic accuracy, sensitivity, specificity, detection rate and Kappa index of conventional-US and RtMR-US were calculated.

Results

Forty-three lesions were detected on CE-MRI before navigation. Eighteen were carcinomas and 25 ILSM. Of these, 21 underwent a RtMR-US. Detection rate on RtMR-US (90.7%) was higher than on conventional-US (43%) (p < 0.001). Agreement between both techniques was low (k = 0.138). Twenty ILSM and 2 LNSM were biopsied. Sixty-five percent were benign (100% of BI-RADS3 and 56% of BI-RADS4-5). Diagnostic performance of RtMR-US identifying malignant nodules for overall lesions and for the subgroup of ILSM was respectively: sensitivity 96.3% and 100%, specificity 18.8% and 30.7%, positive predictive value 66.7% and 43.7%, negative predictive value 75% and 100%. In addition RtMR-US enabled biopsy of 2 metastatic lymph nodes.

Conclusions

Real time-US with supine-MRI using a volume navigation technique increases the detection of ILSM. RtMR-US may be used to detect occult breast carcinomas and to assess cancer extension, preventing unnecessary MRI-guided biopsies and sentinel lymph node biopsies. Incidental lesions BI-RADS 3 non-detected on conventional-US are probably benign.     

Comparison of the diagnostic performance of Magnetic Resonance Imaging (MRI), ultrasound and mammography for detection of breast cancer based on tumor type,breast density and patient's history: A review

ObjectiveBreast cancer is the most common malignancy in women. Mammography and ultrasound are commonly used in a clinical environment as the first choice for breast cancer detection. Magnetic Resonance Imaging (MRI) has been reported to reveal additional information. In the following review MRI, Ultrasound (US) and Mammography (MM) are all compared in terms of their diagnostic performance on breast cancer detection, depending on tumor type, breast density and patient's history.Key findingsEvaluating each modality alone, MRI provided an overall sensitivity and specificity of 94.6% (range 85.7%–100%) and 74.2% (range 25%–100%) respectively, while mammography showed that the overall sensitivity was at 54.5% (range 27%–86.8%) and specificity was 85.5% (range 62.9%–98.8%). The overall sensitivity and specificity of ultrasound was 67.2% (range 26.9%–87.5%) and 76.8% (range 18.8%–96.9%). When combining the results of all three techniques, it resulted in a sensitivity of 97.7% (range 95%–100%) and a specificity of 63.3% (range 37.1%–87.5%). In addition, contrast-enhanced mammography (CE-MM) and MRI (CE-MRI) illustrated an overall sensitivity and specificity for CE-MM was 90.5% (range 80.9%–100%) and 52.6% (range 15%–76.1%) and for CE-MRI, the overall sensitivity and specificity was 91.5% (range 89.1%–93.8%) and 64.7% (range 43.7%–85.7%).ConclusionAs modalities alone, the highest sensitivity has been observed for MRI and the lowest sensitivity for mammography regardless breast type, density, and history. Sensitivity is even more increased from the combination of US + MRI or MM + MRI or MRI + MM + US. The specificity seems to be affected by the size, type of the tumor and patient's history, however based on breast density, the highest specificity was observed by US alone.Implications for practiceBreast cancer screening is of outmost importance and identifying the best technique will improve cancer management. Combining techniques increases diagnostic ability compared with using modalities alone. CE-MM can be a viable option in dense breast tissue when there are contraindications to MRI as it also has high sensitivity based on the type of breast cancer.     

US correlation for MRI-detected breast lesions in women with familial risk of breast cancer

AIM: To examine the value of US correlation for MRI-detected breast lesions in women with familial risk of breast cancer. METHODS: From an initial dataset of 245 women with positive family history who had breast cancer surveillance involving mammography or MRI between November 1994 and February 2001, 179 subjects with follow-up data were selected. A total of 43 women with 48 MRI-detected lesions underwent further assessment with US. Histopathological correlation was available from 38 breast biopsies performed for 33 women. RESULTS: Sonographic correlates were identified in 32 (66.7%) of the 48 MRI-detected lesions, with cancer present in 11 (34.4%) of these. This compares with 1 (6.3%) cancer found in the 16 lesions without sonographic correlates. Of the 12 malignant lesions, 11 (91.7%) had sonographic correlates whereas 21 (58.3%) of the 36 benign lesions had sonographic correlates. In all 74% of breast biopsies were performed under US guidance compared with 8% under MRI guidance. The proportion of MRI- and US-correlated benign and malignant lesions undergoing US-guided biopsy were 85.7% and 90.9%, respectively. CONCLUSION: The probability of cancer was significantly higher in MRI-detected breast lesions with sonographic correlates compared with those without such correlation. The advantage of convenient biopsy under US guidance as opposed to MRI guidance highlights the value of sonographic assessment of MRI-detected breast lesions.     

MR扩散成像确定乳腺癌范围的研究

目的探讨利用MR扩散成像（DWI）和表观扩散系数（ADC）测定确定乳腺癌范围的可行性。方法测定57例59个乳腺癌在扩散敏感因子（b）值分别取500（b=500s·mm^-2组）和1000（b=1000s·mm^-2组）时的ADC值，根据设定的ADC值测量不同b值时的肿瘤范围；比较动态增强和DWI测量病灶大小的异同。以2条径线作为比较参照：病灶最大径、过最大径线中点并与之垂直的径线。所有测量结果与病理对照。结果（1）59个病灶包括浸润性导管癌48个，导管原位癌伴微浸润6个，黏液腺癌3个，髓样癌2个。（2）小于设定ADC值的异常区域作为扩散所测病灶大小。则b值为500和1000s·mm^-2时2组结果与病理检查肿瘤范围比较。范围一致组b=500s·mm^-2组略高于b=1000s·mm^-2组，但差异无统计学意义（χ^2=0．160，P=0．689）；过度诊断2组一致（2个）；假阴性b=500s·mm^-2组略低于b=1000s·mm^-2组（χ^2=0．172，P=0．679）。2组均诊断错误14个，分别是过度诊断2个，假阴性12个。8个病灶2组表现不一致，5个在b值为500s·mm^-2时诊断正确的病灶中，3个是导管原位癌伴微浸润。（3）以4min时测定的大小作为动态增强显示病灶的测定点，与同一层面DWI上显示的异常区域大小进行比较。两者符合47个（80％）；增强径线测定较小而DWI测定符合8个，其中3个为黏液腺癌，5个为浸润性导管癌3级。结论MR DWI和ADC测定可以对乳腺癌范围进行评价。对某些特定病理类型乳腺癌范围的测量，DWI有其优势。     

MR imaging features of pure mucinous carcinoma of the breast

OBJECTIVE: To characterize MR imaging features of pure mucinous carcinoma of the breast. MATERIALS AND METHODS: MR images obtained from 16 women (age range, 29-81; mean age, 57 years) with pure mucinous carcinoma of the breast determined at surgery were reviewed. The MR findings used were shape, margin, internal mass enhancement, kinetic curve pattern on dynamic study, signal intensity on short time inversion recovery (STIR) T2-weighted images, and non-mass-like enhancement around the main tumor. Non-mass-like enhancement was compared with the presence of extensive intraductal component (EIC) on histopathological findings. RESULTS: Eleven tumors (69%) had lobular contour, and nine tumors (56%) had smooth margin. Eight tumors (50%) showed rim enhancement and six tumors (38%) showed heterogeneous enhancement. Fourteen tumors (88%) showed a persistent enhancing pattern on kinetic curve. Fifteen tumors exhibited homogenous strongly high signal intensity on STIR T2-weighted images. In six cases with EIC, five cases had non-mass-like enhancement around the main mass. CONCLUSIONS: MR findings such as lobular shape, rim or heterogeneous enhancement, persistent pattern on kinetic curve, and homogeneous strongly high signal intensity on STIR T2-weighted images may be useful in diagnosing pure mucinous carcinoma. Moreover, linear-ductal enhancement around main mass may indicate presence of EIC.     

Preoperative breast MR Imaging in patients with primary breast cancer has the potential to decrease the rate of repeated surgeries

PurposeThe impact of preoperative MRI on re-excisions and mastectomy rate is discussed controversially in the literature. Aim of this study was to evaluate the effect of preoperative breast MRI on the surgical procedure and rate of repeated surgeries.Material and methodsA total of 991 consecutive patients in the years 2009 and 2010 with 1036 primary breast cancers were retrospectively analyzed. Sixty percent (599 patients with 626 cancers) received preoperative breast MRI. Planned surgical procedures before and after MRI and numbers of repeated surgeries in patients with (MR+ ) and without preoperative MRI (MR−) were compared.ResultsThe result of preoperative MRI changed the surgical procedure in 25% (157/626) of the cases. In 81% (127/157), MRI was beneficial for the patients, as otherwise occult carcinomas were removed (n = 122) or further biopsy could be prevented (n = 5). Mastectomy rates did not differ between MR+ and MR- group (39% vs. 39%). On multiple regression analysis, the MR+ group had a lower chance for repeated surgery (p < 0.05).ConclusionPreoperative MRI could lower the chance for repeated surgery in patients with primary breast cancer. The rate of mastectomy did not differ between patients undergoing preoperative MRI and those who did not.     

Indeterminate or suspicious breast lesions detected initially with MR imaging: value of MRI-directed breast ultrasound

RATIONALE AND OBJECTIVES: To retrospectively determine the value of magnetic resonance imaging (MRI)-directed breast ultrasonography (US) in the evaluation of indeterminate or suspicious lesions identified on contrast-enhanced, breast MRI. MATERIALS AND METHODS: A total of 395 patients presenting for breast MRI during a 4-year period was retrospectively reviewed. Seventy-one patients were recommended for MRI-directed US for further characterization of indeterminate or suspicious breast lesions detected on MRI. Fifty-five patients (all female; age 31-80 years) had US. Their MRI and US were reviewed and tested for correlations with histologic results or long term follow-up. Logistic regression analyses were used to test for associations between MRI lesion characteristics and US detection rate. RESULTS: US identified 46 of 97 (47%) lesions depicted at MRI from 55 patients (47 [85%] of these patients had histories of breast malignancies). Twelve cancers were found from the 97 lesions (12%). Biopsy was avoidable in 10 lesions (10%). The detection rate with US was slightly higher with "mass" (55% [23/42]) lesions described in MRI than "non-mass" lesions or lymph nodes (42% [23/55]). There was a significant positive association (odd ratio = 1.23: 95% CI = 1.05-1.43, P = .01) between US detection rate and MRI mass lesion size. There was no statistical significance between US detection rate and the presence of malignancies; 42% (5/12) of MRI malignant lesions were not visualized with US. CONCLUSIONS: MRI-directed US reduced the number of biopsies required for indeterminate or suspicious MRI lesions. Nevertheless, the lesions which were biopsied had a low rate of malignancy.     

Multidisciplinary Functional MR Imaging for Prostate Cancer

Various functional magnetic resonance (MR) imaging techniques are used for evaluating prostate cancer including diffusion-weighted imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy. These techniques provide unique information that is helpful to differentiate prostate cancer from non-cancerous tissue and have been proven to improve the diagnostic performance of MRI not only for cancer detection, but also for staging, post-treatment monitoring, and guiding prostate biopsies. However, each functional MR imaging technique also has inherent challenges. Therefore, in order to make accurate diagnoses, it is important to comprehensively understand their advantages and limitations, histologic background related with image findings, and their clinical relevance for evaluating prostate cancer. This article will review the basic principles and clinical significance of functional MR imaging for evaluating prostate cancer.     

Functional MR Imaging of Psychogenic Amnesia: A Case Report

We present here a case in which functional MR imaging (fMRI) was done for a patient who developed retrograde psychogenic amnesia for a four year period of her life history after a severe stressful event. We performed the fMRI study for a face recognition task using stimulation with three kinds of face photographs: recognizable familiar faces, unrecognizable friends'' faces due to the psychogenic amnesia, and unfamiliar control faces. Different activation patterns between the recognizable faces and unrecognizable faces were found in the limbic area, and especially in the amygdala and hippocampus.     

The role of second-look ultrasound of BIRADS-3 mammary lesions detected by breast MR imaging

Objective

To asses the value of second-look ultrasound (US) for identifying BIRADS 3 (Breast Imaging Reporting Data System) mammary lesions detected by breast Magnetic Resonance imaging (MRI).

Materials and methods

From April 2008 to May 2009 330 breast MRI were performed of which 60 patients are classified as BIRADS 3. 84 lesions underwent second-look US and percutaneous vacuum biopsy Vacora system US-guided. Statistical analysis: lesions were stratified into two groups: visible on US (Group 1) and not visible on US (Group 2).The clinical impact of second-look US was studied in terms of negative predictive value (NPV).

Results

The positive predictive value (PPV) of category 3 BIRADS MRI was found to be 89%. Second look-US results detected lesions in 51% of the MRI enhancing lesions. The second look-US showed a NPV of 97%. The NPV of second look-US was significantly greater than the NPV of MRI BIRADS 3 (97% vs 89%, p < 0.05). The logistic regression analysis showed a higher number of malignant lesions in group 1 than in group 2 (7vs 2, OR 3.7, p < 0.05).

Conclusions

The second-look US permitted the correct management of subcentimetric MRI BIRADS 3 lesions not visible with conventional imaging tecniques.     

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

Background parenchymal enhancement in breast MRIs of breast cancer patients: Impact on tumor size estimation

Objective

To evaluate whether the degree of background parenchymal enhancement affects the accuracy of tumor size estimation based on breast MRI.

Methods

Three hundred and twenty-two patients who had known breast cancer and underwent breast MRIs were recruited in our study. The total number of breast cancer cases was 339. All images were assessed retrospectively for the level of background parenchymal enhancement based on the BI-RADS criteria. Maximal lesion diameters were measured on the MRIs, and tumor types (mass vs. non-mass) were assessed. Tumor size differences between the MRI-based estimates and estimates based on pathological examinations were analyzed. The relationship between accuracy and tumor types and clinicopathologic features were also evaluated.

Results

The cases included minimal (47.5%), mild (28.9%), moderate (12.4%) and marked background parenchymal enhancement (11.2%).The tumors of patients with minimal or mild background parenchymal enhancement were more accurately estimated than those of patients with moderate or marked enhancement (72.1% vs. 56.8%; p = 0.003). The tumors of women with mass type lesions were significantly more accurately estimated than those of the women with non-mass type lesions (81.6% vs. 28.6%; p < 0.001). The tumor of women negative for HER2 was more accurately estimated than those of women positive for HER2 (72.2% vs. 51.6%; p = 0.047).

Conclusion

Moderate and marked background parenchymal enhancement is related to the inaccurate estimation of tumor size based on MRI. Non-mass type breast cancer and HER2-positive breast cancer are other factors that may cause inaccurate assessment of tumor size.     

乳腺癌MR弥散加权成像研究进展

MR在乳腺癌诊断方面的应用价值已经得到广泛认同,为增加检出乳腺癌的敏感性,需应用多种MR扫描技术。然而,常规MR在检测及描述乳腺病变特征时具有一定的局限性,弥散加权成像作为一种重要的功能成像技术,能够反映组织的生物物理学特征,有较大的发展前景。弥散加权成像是唯一能够检测活体组织内水分子弥散运动的非侵入性方法,可以检测出组织结构在分子水平上的改变。其成像时间短,敏感性高,无需使用对比剂,并且能比常规MR检查更早的发现病变,因此,它已经广泛应用于脑部疾病中,也越来越多地应用于乳腺疾病方面。本文就弥散加权成像在乳腺癌的应用方面予以综述。     

The role of magnetic resonance imaging and ultrasound in patients with adnexal masses

AIMS: To evaluate the accuracy of ultrasonography (US) and magnetic resonance imaging (MRI) in characterizing adnexal masses, and to determine which patients may benefit from MRI. METHODS: We prospectively studied 72 women (mean age 53 years, range 19 to 86 years) with clinically suspected adnexal masses. A single experienced sonographer performed transabdominal and transvaginal greyscale spectral and colour Doppler examinations. MRI was carried out on a 1.5T system using T1, T2 and fat-suppressed T1-weighted sequences before and after intravenous injection of gadolinium. The adnexal masses were categorized as benign or malignant without knowledge of clinical details, according to the imaging features which were compared with the surgical and pathological findings. RESULTS: For characterizing lesions as malignant, the sensitivity, specificity and accuracy of MRI were 96.6%, 83.7% and 88.9%, respectively, and of US were 100%, 39.5% and 63.9%, respectively. MRI was more specific (p<0.05) than US. Both MRI and US correctly diagnosed 17 (24%) cases with benign and 28 (39%) cases with malignant masses. MRI correctly diagnosed 19 (26%) cases with benign lesion(s), which on US were thought to be malignant. The age, menopausal status and CA-125 levels in these women made benign disease likely, but US features were suggestive of malignancy (large masses and solid-cystic lesions with nodules). CONCLUSION: MRI is more specific and accurate than US and Doppler assessment for characterizing adnexal masses. Women who clinically have a relatively low risk of malignancy but who have complex sonographic features may benefit from MRI.     

Image-guided focused ultrasound ablation of breast cancer: current status, challenges, and future directions

Image-guided focussed ultrasound (FUS) ablation is a non-invasive procedure that has been used for treatment of benign or malignant breast tumours. Image-guidance during ablation is achieved either by using real-time ultrasound (US) or magnetic resonance imaging (MRI). The past decade phase I studies have proven MRI-guided and US-guided FUS ablation of breast cancer to be technically feasible and safe. We provide an overview of studies assessing the efficacy of FUS for breast tumour ablation as measured by percentages of complete tumour necrosis. Successful ablation ranged from 20% to 100%, depending on FUS system type, imaging technique, ablation protocol, and patient selection. Specific issues related to FUS ablation of breast cancer, such as increased treatment time for larger tumours, size of ablation margins, methods used for margin assessment and residual tumour detection after FUS ablation, and impact of FUS ablation on sentinel node procedure are presented. Finally, potential future applications of FUS for breast cancer treatment such as FUS-induced anti-tumour immune response, FUS-mediated gene transfer, and enhanced drug delivery are discussed. Currently, breast-conserving surgery remains the gold standard for breast cancer treatment.     

FLAIR imaging for multiple sclerosis: a comparative MR study at 1.5 and 3.0 Tesla

The purpose of this study was (1) to identify the optimal TE for FLAIR-imaging at 3.0 T assessing three different echo times qualitatively and quantitatively and (2) to evaluate the diagnostic efficacy of high-field 3.0-T FLAIR imaging in comparison to conventional 1.5-T MRI in patients with multiple sclerosis (MS). Twenty-two patients with clinically definite MS underwent axial FLAIR imaging at 1.5 and 3.0 T. In 15 of these patients further FLAIR images with a TE of 100, 120 and 140 ms were acquired at 3.0 T. Imaging protocols were modified for 3.0 T using the increased SNR to acquire more and thinner slices while maintaining a comparable scan time. FLAIR images of either different TEs or different field strengths were ranked for each patient qualitatively by two observers. Signal intensity measurements were obtained in the gray and white matter, CSF and representative white matter lesions (WML). At 3.0 T, a TE of 100 and 120 ms proved superior in all qualitative categories when compared to 140 ms. In the quantitative assessment CNR of WML was highest for 120 ms (CNR: 19.8), intermediate for 100 ms (17.2) and lowest for 140 ms (15.3) (P<0.003). For lesion conspicuity and overall image quality, 3.0 T was judged superior to 1.5 T, whereas no difference was found for gray-white differentiation and image noise. With regard to artifacts, 3.0 T was inferior to 1.5 T. The CNR for WML was slightly lower at 3.0 T, but the difference was not significant (22.6 vs. 28.0, P=ns). However, significantly more WML were detected at 3.0 T than at 1.5 T (483 vs. 341, P<0.0001). The optimal echo time for FLAIR imaging at 3.0 T is 120 ms due to the significantly higher CNR of WML. By trading the higher SNR at 3.0 T for better spatial resolution, nearly the same CNR level could be maintained, increasing lesion detectability at 3.0 T compared to 1.5 T. Thus, high-field MRI may further strengthen the role of MRI as the most sensitive paraclinical test for the early diagnosis of MS.     

乳腺癌患者新辅助化疗的MRI研究

乳腺癌新辅助化疗(亦称初始化疗或术前化疗)最初是指对局部晚期乳腺癌患者手术治疗之前所进行的辅助化疗,目前己将该治疗扩展至肿瘤较大的可手术的乳腺癌患者,以使肿瘤降期,进而达到保乳手术治疗的目的。随着新辅助化疗在乳腺癌患者中不断推广应用,临床实践中迫切需要一种能准确评价化疗后肿瘤变化的检查方法,本文对RI(magnetic resonance imaging)在乳腺癌新辅助化疗中的研究进行综述。     

三阴性乳腺癌的MRI影像学特点分析

目的：探讨三阴性乳腺癌（TNBC）的特征性MRI影像学表现,并与非三阴性乳腺癌比较。方法：分析有完整资料的90例乳腺癌,所有病例术前均行乳腺MRI检查并经手术或病理证实,其中三阴性乳腺癌23例,非三阴性乳腺癌67例。纳入分析的病灶MRI表现包括病灶形状、边界、大小、数目、内部强化、时间信号强度曲线（TIC）类型和表观扩散系数（ADC）,并将MRI表现与病理结果作对照。结果：与非三阴性乳腺癌相比,TNBC在MRI上大多表现为边缘光整、环状强化及更低的ADC值。而在患者年龄,病灶形状、大小、数目及TIC上,差异无统计学意义（P〉0.05）。结论：乳腺癌MRI表现中病灶边界光整、增强时环状强化、较低的ADC值对诊断TNBC具有一定参考价值。     

MR背景抑制扩散加权成像在乳腺癌的应用

目的 探讨MR扩散加权成像(DWI)结合短时间反转恢复回波成像(STIR-EPI)背景抑制(BS)技术在乳腺癌成像的技术参数及其可行性.方法 回顾性分析26例乳腺癌的MR DWIBS测得各组织的表观扩散系数(ADC),利用三维最大强度投影(3D-MIP)重组及黑白反转技术,观察病变显示效果.观察乳腺痛DWI及DWIBS两种方法的显示率.对乳腺各组织的ADC值进行随机区组设计的方差分析,在乳腺癌与良性病变ADC值的比较中,采用t检验.对两种成像方法乳腺癌的显示率进行配对资料X2检验.结果 在扩散敏感因子(b)=800 mm2/s的图像中,乳腺癌多表现为高信号,其ADC值分别为:肿瘤实质(0.93±0.25)×10-3 mm2/s、瘤内坏死灶(2.06±0.17)×10-3 mm2/s、正常腺体(1.92±0.23)×10-3 mm2/s、转移性淋巴结(1.10 ± 0.14)×10-3mm2/s,各种组织间两两比较,差异具有统计学意义(P值均＜0.01).DWIBS经MIP重组及黑白反转技术,病变周围组织信号被抑制,得到类正电子发射体层成像(PET)图像.在乳腺癌中,DWIBS对肿瘤实质(92.3/)及转移性淋巴结(88.4/)的显示率要高于DWI序列(分别为57.6/和42.3/),差异有统计学意义(x2值分别为8.307、12.235,P均＜0.05).乳腺癌与良性病变ADC值分别为(1.092±0·17)×10-3和(2.154±0.53)×10-3mm2/s,差异有统计学意义(t=8.626,P＜0.05).结论 MRDWIBS在显示病灶方面有一定优势,应用DWI结合ADC值对乳腺癌的诊断具有临床应用前景.