Application of the Kaiser score by MRI in patients with breast lesions by ultrasound and mammography

PURPOSEThis study aimed to verify whether the use of the Kaiser score can improve the diagnostic performance in breast magnetic resonance imaging (MRI) for suspicious lesions and avoid further invasive diagnostic approaches.METHODSThis retrospective study enrolled 97 patients who underwent breast MRI before undergoing breast biopsy or surgery. Evaluations were conducted on all MRI images individually by 2 radiologists using the Kaiser score. Neither radiologist had the knowledge of the final histopathological diagnosis. The ability of the Kaiser score in diagnosis was established via a receiver performing characteristic (ROC) analysis, which was measured by the area under the ROC curve (AUC). Youden index was used to define the optimal cutoff value. Kaiser score categories were dichotomized into positive (cutoff score > 4) and negative scores (cutoff score ≤ 4). Cohen’s kappa coefficient was used to analyze the inter-rater agreement.RESULTSHistopathology revealed 56 malignant and 41 benign lesions. The AUC for all lesions evaluated by the Kaiser score was 0.992 (95% CI: 0.981-1.0) and 0.958 (95% CI: 0.920-0.996) for 2 radiologists, respectively. Inter-rater agreement of the dichotomized Kaiser score was excellent (κ = 0.894, P < .001). A total of 20 lesions (33.8%) previously categorized as BI-RADS 4 were reduced to BI-RADS 2/3 (19 benign lesions and 1 malignant lesion).CONCLUSIONThe Kaiser score is a valuable auxiliary diagnostic tool for improving the diagnostic ability of radiologists, whose experiences in breast MRI are diverse. In some cases, the application of the Kaiser score could possibly avoid unnecessary breast biopsies.     

MRI as a complementary tool for the assessment of suspicious mammographic calcifications: Does it have a role?

IntroductionMammography remains the standard imaging modality for the identification and characterization of breast calcifications. However, its low specificity results in high biopsy rates in cases of suspicious calcifications.ObjectivesTo evaluate the diagnostic performance of MRI as an additional tool in the assessment of suspicious mammographic calcifications and to identify the enhancement patterns most related to malignancy.MethodsAn observational, prospective, cross-sectional, bi-centre study was conducted including consecutive patients with suspicious calcification groups on mammography (BI-RADS® 4 and 5). Anatomopathological results obtained from biopsies were considered the reference standard, and the patients were followed up for at least two years. MRI examinations were interpreted by two radiologists in consensus. The chi-square test was used to evaluate the correlation between MRI features and histological results. The overall diagnostic performance of MRI for malignancy was calculated.Results162 female patients were included (mean age, 53 years; range 34–82 years), with 163 mammographic lesions, of which 77 (47.2%) were benign, 64 (39.3%) malignant, and 22 (13.5%) precursor lesions on histopathology. Malignant lesions demonstrated a significantly higher presence of enhancement (56/64; 87.5%) than benign lesions (17/77; 22.1%) (p < 0.001). Non-mass enhancement (NME) was the morphology most related to malignant lesions (38/56; 67.9%). The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of MRI for malignancy were 81.5%, 87.5%, 77.8%, 71.8%, and 90.5%, respectively.ConclusionMRI performed as an adjunct tool allows to increase imaging specificity for malignancy in suspicious calcifications, which may contribute to reduce the need for biopsy.     

Calcifications associated with lactational changes of the breast: mammographic findings with histologic correlation

OBJECTIVE: We sought to describe the mammographic appearance of calcifications associated with histologically confirmed lactational changes of the breast. CONCLUSION: Calcifications associated with lactational changes of the breast may have a suspicious appearance on mammography. These calcifications may be identified on a patient's original screening mammogram or may be a new finding on an annual screening examination. Correlating a clinical history of recent lactation or a postpartum state is important in establishing a concordance between the mammographic and histologic findings. However, despite the benign nature of these calcifications, biopsy is recommended because of their suspicious morphologic features.     

Predictive value of mammography in early detection of breast cancer: Analysis of histological findings in breast biopsies indicatedonly by mammography

From 1985 to 1989 breast biopsies were performed in 1835 patients with suspicious mammographic findings. Inasive cancers were diagnosed in 274 patients in-situ cancers in 186. The predictive value of mammography (0.33) was correlated with the age of patient, and compared with data in the literature. The prevalence of benign and malignant lesions was correlated with the mammographic features. We suggest that the predictive value of mammography, and the ration of noninvasive to invasive cancers detected would be optimal criteria for quality control of Offprint requests to: I.Schreer     

Critical review of 215 cases of non-palpable mammary lesions]

PURPOSE: The natural history of human breast cancer shows that lesion size correlates directly with nodal metastases and distant spread. Nodal metastases are found in only 6% of cases in the preclinical stage of the tumor and therefore imaging must detect a breast cancer before it becomes palpable. We reviewed 215 nonpalpable breast lesions studied in the last 10 years to assess observers performance and ultimately improve the interpretation of suspicious mammograms, evaluating "cost" in terms of the ratio between benign and malignant lesions (B/M). MATERIAL AND METHODS: From 1988 to October 1998, two hundred and fifteen women with nonpalpable breast lesions suspected at mammography were examined. The lesions were removed after stereotaxic or US location and a radiograph of the surgical specimen was always performed. Mammographic patterns were interpreted retrospectively by two blinded radiologist experienced in breast imaging and specialized in locating nonpalpable breast lesions. Mammographic patterns were classified as poorly/highly suspicious calcifications, regular/irregular masses, spiculated masses, masses with calcifications and parenchymal distortions. Radiographic findings were compared with surgical results and the data used to calculate the B/M, positive predictive value (PPV) for malignancy and the trend of operator's performance. RESULTS: Modern techniques permit to detect a very high number of in situ breast carcinomas. Nineteen of 22 lesions (86%) were detected by mammography as highly suspicious calcifications, 2/22 as spiculated masses and 1/22 as a mass with calcifications. No in situ carcinoma was detected as an irregular mass. All regular masses were proven to be benign at histology. B/M analysis showed a decreasing trend (from 1.94 in the first 3 years to .57 in 1994-96, to .83 in 1997-98) and an overall value of .90. The PPV for malignancy was 83.33% for spiculated masses, 65.5% for highly suspicious calcifications, 63.63% for irregular masses, 47.05% for masses with more or less dysmorphic calcifications, 32.65% for poorly suspicious calcifications, 8.33% for parenchymal distortions and 0% for regular masses. DISCUSSION AND CONCLUSIONS: All spiculated masses and highly suspicious calcifications and microcalcifications should be removed. Biopsy is recommended in parenchymal distortions, despite its low predictive value for malignancy, because these lesions are uncommon and the cost of biopsy is therefore acceptable. Needle aspiration or long-term monitoring can be reconsidered for irregular masses and poorly suspicious microcalcifications. Finally, relative to possible different interpretations of mammographic patterns by center and operator's experience, we suggest that the PPV for every single pattern be continually reassessed based on personal case records rather than on literature data. This holds true especially for microcalcifications.     

Magnetic resonance-guided biopsy of suspicious breast lesions with a handheld vacuum biopsy device

Purpose: To evaluate a handheld vacuum-assisted device system for magnetic resonance image (MRI)-guided breast lesion biopsy.

Material and Methods: In 32 patients, a total of 42 suspicious breast lesions (mean diameter 7.5 mm for mass lesions, 11.6 mm for non-masslike diffuse lesions) seen with MRI (no suspicious changes in breast ultrasound or mammography) were biopsied (27 lateral, 15 medial) using a 10G vacuum-assisted breast biopsy device under MR guidance. Histology of biopsy specimens was compared with final histology after surgery or follow-up in benign lesions.

Results: In all biopsies, technical success was achieved. Histology revealed 11 lesions with ductal carcinoma in situ (DCIS) or invasive cancer, three with intermediate lesions (LCIS) and 28 with benign breast lesions (adenosis, infected hematoma). In one patient with discordant results of MRI and histology, surgical excision revealed medullary cancer. In the follow-up (mean 18 months) of the histological benign lesions, no breast cancer development was observed. Besides minor complications (hematoma, n = 6), with no further therapeutic interventions, no complications occurred.

Conclusion: MRI-guided breast lesion biopsy using a handheld vacuum-assisted device is a safe and effective method for the work-up of suspicious lesions seen with breast MRI without changes in mammography or ultrasound. In the case of discordant histology of vacuum biopsy and breast MRI appearance, surgical excision is recommended.     

乳腺X线摄影及MRI结合临床特征对乳腺高危病变诊断价值

目的探讨乳腺X线摄影及MRI征象结合临床特征预测乳腺高危病变恶性升级的价值。方法回顾性分析复旦大学附属肿瘤医院2017年1月至2018年3月经病理证实为乳腺高危病变,且活检前行乳腺X线摄影和MRI检查的230例患者。分析乳腺病变X线摄影及MRI征象,并以病理结果为金标准,评估高危病变升级率与临床及影像特征的关系。采用独立样本t检验与χ2检验比较升级组与未升级组患者临床及影像特征的差异,采用受试者操作特征(ROC)曲线比较乳腺X线和MRI对乳腺高危病变升级率的诊断效能,采用Binary logistic回归分析比较高危病变升级率与临床、影像学征象之间的关系。结果230例患者病灶均为单发。47例在后续再手术中升级为恶性病变,升级率为20.4%(47/230)。未升级组与升级组乳腺高危病变患者的年龄、病灶最大径以及绝经状态差异有统计学意义(P<0.05)。未升级组和升级组患者间的乳腺X线摄影征象的差异无统计学意义(P>0.05),乳腺MRI征象和MRI背景实质强化的差异有统计学意义(P<0.05)。乳腺X线摄影和MRI评估高危病变升级为恶性病变的ROC曲线下面积分别为0.606、0.913,MRI诊断优于乳腺X线摄影(Z=6.919,P<0.01)。单因素分析结果显示,年龄、病灶最大径、中重度背景强化为预测高危病变升级的正相关因素,已绝经、MRI诊断阴性为预测高危病变升级的负相关因素(P<0.05);多因素分析显示,年龄以及MRI背景实质强化是预测乳腺高危病变升级的独立因素(P<0.01)。结论MRI对高危病变升级的诊断效能优于乳腺X线,年龄越大,MRI背景实质强化中重度可提示高危病变的恶性升级。     

Scintimammography with 99mTc-MIBI versus dynamic MRI for non-invasive characterization of breast masses

Although mammography remains the technique of choice for the early detection of breast cancer, several imaging techniques, including scintimammography and magnetic resonance imaging (MRI), have recently been proposed as adjuncts for this purpose and included in many diagnostic protocols. This study was undertaken to assess the clinical accuracy of scintimammography with technetium-99m methoxyisobutylisonitrile (MIBI) and contrast-enhanced MRI in the detection of primary breast carcinoma in patients with equivocal mammographic findings. Forty-nine patients with a suspicious breast mass detected either by physical examination or by mammography and ultrasound (US) were studied. All patients underwent scintimammography and dynamic contrast-enhanced MRI 1 week apart. The results of the two techniques were compared and correlated to the final diagnoses. Two independent readers reported the scans using a four-point confidence scale. The areas under the receiver operator characteristic (ROC) curves were obtained. Scintimammography showed an accuracy for tumour detection of 84%, with a sensitivity of 80% and a specificity of 88%. MRI showed an accuracy of 86%, with a sensitivity and specificity of 96% and 75%, respectively. Comparison of the two areas under the ROC curves showed no significant differences between MRI, 0.91+/-0.05 (mean+/-SD), and scintimammography, 0.88+/-0.05 (P=0.9). It is concluded that dynamic MRI and scintimammography possess comparable accuracy in the diagnosis of primary breast carcinoma in patients with equivocal mammographic or US findings.     

乳腺X线摄影BI-RADS 0级诊断的分析探究

目的：对乳腺影像报告和数据系统BI-RADS 0级诊断的成因进行探索。方法收集我院2012年10月～2013年5月期间,乳腺摄影BI-RADS诊断为0级的女性患者53位,0级病灶共55例,回顾性分析此类病灶的影像学表现并统计各种表现中恶性病变所占比例。结果诊断为BI-RADS 0级的病灶均出现在致密型（33例）或混合型腺体（22例）中,无脂肪型腺体。乳腺摄影BI-RADS 0级病灶的常见影像表现有：①腺体局部结构异常（不对称致密或结构扭曲紊乱）20例;②边界不清的可疑结节影28例;③可疑钙化灶28例。各种影像可单独或合并存在,恶性病变所占比例由高到低分别为：仅表现为可疑钙化者57．1％（4/7）,可疑结节伴可疑钙化者27．3％（3/11）,腺体局部结构异常伴可疑钙化者20％（2/10）,仅表现为腺体局部结构异常者10％（1/10）,仅表现为可疑结节者5．9％（1/17）。结论由于各种主客观原因,乳腺摄影的BI-RADS 0级诊断无法避免。对于致密或混合型腺体,需要特别注意上述BI-RADS 0级病灶的常见影像表现,尤其是可疑钙化灶的存在。     

The postconservation breast: part 2, Imaging findings of tumor recurrence and other long-term sequelae

OBJECTIVE: The objectives of this article are to highlight the imaging findings of tumor recurrence and other long-term potential sequelae after breast-conserving surgery and radiation therapy, including increased risk of infection and radiation-induced malignancies. The role of MRI as a problem-solving tool in evaluating the conservatively treated breast will also be discussed. CONCLUSION: Imaging the treated breast presents challenges because of its limited compressibility and overlapping features of benign posttreatment alterations and tumor recurrence. After lumpectomy and radiation therapy, mammographic findings such as breast edema, skin thickening, fluid collections, architectural distortion, and calcifications have characteristic sequences of evolution toward stability. Changes in the imaging appearance after stability has been achieved--including increasing asymmetry, an enlarging mass, increasing edema or skin thickening, and the development of pleomorphic calcifications within or near the operative bed--should alert the radiologist to possible tumor recurrence. When mammography or sonography is indeterminate, MRI may be useful in excluding recurrence or providing a means for biopsy of a suspicious finding.     

The clinical value of bilateral breast MR imaging: is it worth performing on patients showing suspicious microcalcifications on mammography?

The purpose of this study was to evaluate the clinical value of bilateral breast magnetic resonance (MR) imaging (MRI) in patients showing suspicious microcalcifications on mammography and negative ultrasound findings. Fifty patients underwent MRI before stereotactic vacuum-assisted breast biopsy (SVAB). MR findings were classified into five types for interpretation, and types 4 and 5 were considered malignant. SVAB revealed 13 carcinomas and 37 benign lesions. Malignant lesions were more frequently found in cases of positive MRI diagnoses than in negative MRI diagnoses (P < 0.001). Mammography had a sensitivity of 100%, a specificity of 24% and an accuracy of 44%, whereas mammography plus MRI had a sensitivity of 85%, a specificity of 100% and an accuracy of 96%. In the evaluation of mammographically detected microcalcifications, bilateral breast MRI is of good diagnostic value and may alter the indications for SVAB.     

Optimization of X-ray mammography and technetium-99m methoxyisobutylisonitrile scintimammography in the diagnosis of non-palpable breast lesions

The purpose of this study was to evaluate the contribution of technetium-99m methoxyisobutylisonitrile (MIBI) scintimammography to the early diagnosis of breast cancer in 78 patients with non-palpable breast lesions detected by mammography. In all cases biopsy was indicated and they were classified into three groups according to the mammographic findings: high (28), intermediate (30) and low (20) mammographic probability of malignancy. Histological diagnosis confirmed 37 benign and 41 malignant lesions. In the high-probability group ^99mTc-MIBI scintimammography changed the four false-positives into true negatives at the expense of two false-negatives; in the intermediate group it changed nine of the 17 false-positives into true-negatives at the expense of one false-negative, and in the low-probability group it changed five of the 16 false-positives into true-negatives without false-negatives. Applying scintimammography to patients included in the intermediate and low-probability groups together, 14 of the 33 mammographic false-positives were changed into true-negatives with 1 false-negative; thus, 41% of the unnecessary biopsies would have been avoided. When MIBI scintimammography was applied to the low-probability group, the negative predictive value was 100% and the unnecessary biopsies would have been reduced by 31%. Received 10 November 1997 and in revised form 19 January 1998     

X线及MRI对聚丙烯酰胺凝胶隆胸后乳腺病变诊断价值的评价与比较

目的对聚丙烯酰胺凝胶(PAG)注射式隆胸术后,出现并发症或合并乳腺其他病变的X线与MRI的诊断价值进行评估。方法回顾性分析26例PAG隆胸术后钼靶X线与MRI的影像表现。结果钼靶X线及MRI能显示充填物位置、形态,合并乳腺病变4例,X线全部漏诊,MRI能检出病灶。结论钼靶X线是PAG隆胸术后普查、随访的首选方法,但出现并发症或者合并乳腺病变时,MRI具有无法比拟的优越性,在临床诊断与治疗中发挥了重要作用。     

Mammography-guided stereotactic fine-needle aspiration cytology of nonpalpable breast lesions: prospective comparison with surgical biopsy results

We assessed the usefulness of fine-needle aspiration cytology (FNAC) in evaluating nonpalpable breast abnormalities by prospectively performing stereotactic mammography-guided FNAC on 100 women undergoing surgical excisional biopsy. Mammographic and cytologic diagnoses, on a scale of 1 (benign) to 4 (malignant), were assigned for each case and compared with the surgical pathologic diagnosis. Sensitivity and specificity were examined at different diagnostic cutoff points for regarding a mammographic or cytologic diagnosis as positive or negative. Of the 100 breast biopsy specimens, 70 were benign and 30 were malignant. For both mammography and FNAC, the optimal diagnostic cutoff point was between diagnosis 2 (mammography, probably benign; cytology, atypical) and 3 (mammography and cytology both suspicious for malignancy). At this cutoff point, FNAC had a sensitivity of 0.77 and specificity of 1.00, vs 0.73 sensitivity and 0.79 specificity for mammography. Pearson coefficient analysis revealed significant correlations between both mammographic and FNAC diagnoses and surgical pathology (p less than .001 for both). Our results suggest that use of mammography-guided FNAC may reduce the number of breast biopsies performed for benign lesions.     

Incremental clinical value of ultrasound in men with mammographically confirmed gynecomastia

Purpose

To determine whether ultrasound is of any value in male patients presenting with focal symptoms who have classic features of gynecomastia but no concerning findings on mammography.

Materials and Methods

Over a 3-year period, all male patients who underwent mammographic evaluation were identified in this retrospective study. Patients with a mammographic diagnosis of gynecomastia and subsequent breast ultrasound at a large tertiary academic medical center comprised the study cohort. Men whose ultrasound diagnosis differed from the initial mammographic evaluation were analyzed for both additional benign findings as well as findings that warranted biopsy.

Results

A total of 353 mammograms were obtained from 327 unique patients (ages 18–95, mean 51 years). Of all mammographic examinations, gynecomastia was the sole finding in 73% (259). In those 259 studies, 85% were further evaluated with ultrasound, in which 6 (2.7%) showed additional benign findings, and 4 (1.8%) showed suspicious findings for which biopsy was recommended. No malignancies were detected in those patients. Furthermore, no malignancies were detected in patients whose mammogram revealed only normal fatty parenchyma or only gynecomastia. In all cases of cancer, mammography revealed visible masses.

Conclusion

Judicious use of breast ultrasound in men improves outcome. Our data suggest that targeted ultrasound is of limited value in symptomatic male patients where mammography is negative or reveals only gynecomastia and leads to unnecessary benign biopsies in these patients. When mammography reveals concerning findings, ultrasound adds positively to clinical management.     

Breast cancer: mammographic and sonographic findings after augmentation mammoplasty

The authors retrospectively reviewed 11 cases of breast cancer in patients who had undergone augmentation mammoplasty. The mammogram or sonogram was abnormal in 10 patients, including six with an abnormal mammographic density or ultrasound study and four with calcifications. One patient had dense breasts and no suspicious findings at mammography. In four patients without palpable findings in the breast, the malignancy was initially detected by means of mammography. In five of six patients with a palpable breast mass, special mammographic views and sonography were helpful in evaluating the mass. Lymph nodes were not involved in six (60%) of the 10 patients with ductal carcinomas. The detection of breast cancer in the augmented breast by means of mammography is possible, even in patients without palpable findings. Modified-position views and sonography may be helpful in evaluating palpable masses. Patients with implants who develop cancer do not necessarily present at a more advanced stage.     

Real-time virtual sonography (RVS)-guided vacuum-assisted breast biopsy for lesions initially detected with breast MRI

Purpose

To report on our initial experiences with a new method of real-time virtual sonography (RVS)-guided 11-gauge vacuum-assisted breast biopsy for lesions that were initially detected with breast MRI.

Materials and methods

RVS-guided 11-gauge vacuum-assisted biopsy is performed when a lesion with suspicious characteristics is initially detected with breast MRI and is occult on mammography, sonography, and physical examination. Live sonographic images were co-registered to the previously loaded second-look spine contrast-enhanced breast MRI volume data to correlate the sonography and MR images.

Results

Six lesions were examined in six consecutive patients scheduled to undergo RVS-guided 11-gauge vacuum-assisted biopsy. One patient was removed from the study because of non-visualization of the lesion in the second-look spine contrast-enhanced breast MRI. Five patients with non-mass enhancement lesions were biopsied. The lesions ranged in size from 9 to 13 mm (mean 11 mm). The average procedural time, including the sonography and MR image co-registration time, was 25 min. All biopsies resulted in tissue retrieval. One was fibroadenomatous nodules, and those of four were fibrocystic changes. There were no complications during or after the procedures.

Conclusion

RVS-guided 11-gauge vacuum-assisted breast biopsies provide a safe and effective method for the examination of suspicious lesions initially detected with MRI.     

Feasibility of MRI-guided large-core-needle biopsy of suspiscious breast lesions at 3 T

The feasibility of large-core-needle magnetic resonance imaging (MRI)-guided breast biopsy at 3 T was assessed. Thirty-one suspicious breast lesions shown only by MRI were detected in 30 patients. Biopsy procedures were performed in a closed-bore 3-T clinical MR system on a dedicated phased-array breast coil with a commercially available add-on stereotactic biopsy device. Tissue sampling was technically successful in 29/31 (94%) lesions. Median lesion size (n = 29) was 9 mm. Histopathological analysis showed 19 benign lesions (66%) and one inconclusive biopsy result (3%). At follow-up of these lesions, 15 lesions showed no malignancy, no information was available in three patients and two lesions turned out to be malignant (one lesion at surgical excision 1 month after biopsy and one lesion at a second biopsy because of a more malignant enhancement curve at 12-months follow-up MRI). Nine biopsy results showed a malignant lesion (31%) which were all surgically removed. No complications occurred. MRI-guided biopsy at 3 T is a safe and effective method for breast biopsy in lesions that are occult on mammography and ultrasound. Follow-up MRI at 6 months after the biopsy should be performed in case of a benign biopsy result.     

Comparison of the diagnostic performance of high-frequency ultrasound as a first- or second-line diagnostic tool in non-palpable lesions of the breast

To compare the diagnostic performance of high-frequency ultrasound (HFU) as a first- or second-line diagnostic tool in non-palpable lesions (NPL) of the breast and to define the place of HFU in the diagnostic process, 89 women with this kind of lesion, previously detected by mammography, underwent HFU with 7.5–13 MHz transducers. The examinations were performed by two equally experienced operators of which only one (operator I) was aware of the mammographic findings. The mammographic examinations revealed the following non-palpable lesions: asymmetry-hyperdensity (17 cases), nodule (44 cases), stellate lesion (5 cases), microcalcifications (23 cases). Total sensitivity of HFU in the examinations performed by operator I was 83 %, while in the examinations performed by operator II (unaware of the mammographic findings) it was only 35 %. In all cases HFU allowed the operators to determine the basic features of the lesions. Our experience confirms that ultrasonography, even if performed with high frequency, cannot be proposed as a screening examination but may profitably be employed as a second-step technique to characterize NPL previously identified by mammography. This ’second-step' role can do the following: rule out true pathology (cases of false-positive mammography findings); furnish some basic features in the case of focal lesions; show other findings in the case of microcalcifications, such as microcysts, ’filled duct' appearance, parenchymal inhomogeneities and nodules; guide interventional procedures; and localize lesions preoperatively. Received: 15 April 1996; Accepted: 2 January 1997     

MRI-only lesions: application of diffusion-weighted imaging obviates unnecessary MR-guided breast biopsies

Objective

To assess if the application of diffusion-weighted imaging (DWI) obviates unnecessary MR-guided biopsies in suspicious breast lesions visible only on contrast-enhanced MRI (CE-MRI).

Methods

This institutional review board (IRB)-approved, retrospective, single-centre study included 101 patients (mean age, 49.5; SD 13.9 years) who underwent additional DWI at 1.5 T prior to MRI-guided biopsy of 104 lesions classified as suspicious for malignancy and visible on CE-MRI only. An experienced radiologist, blinded to histopathologic and follow-up results, measured apparent diffusion coefficient (ADC) values obtained from DWI. Diagnostic accuracy was investigated using receiver operating characteristics (ROC) analysis.

Results

Histopathology revealed 20 malignant and 84 benign lesions. Lesions were masses in 61 (15 malignant, 24.6 %) and non-masses in 43 cases (five malignant, 11.6 %). Mean ADC values were 1.53?±?0.38?×?10^?3 mm²/s in benign lesions and 1.06?±?0.27?×?10^?3 mm²/s in malignant lesions. ROC analysis revealed exclusively benign lesions if ADC values were greater than 1.58?×?10^?3 mm²/s. As a consequence, 29 false-positive biopsies (34.5 %) could have been avoided without any false-negative findings. Both in mass and in non-mass lesions, rule-in and rule-out criteria were identified using flexible ADC thresholds based on ROC analysis.

Conclusion

Additional application of DWI in breast lesions visible only on MRI can avoid false-positive, MR-guided biopsies. Thus, DWI should be an integral part of breast MRI protocols.

Key Points

? DWI measurements are a fast and helpful technique for improved breast lesion diagnosis ? DWI application in breast lesions visible only on MRI obviates false-positive, MR-guided biopsies ? Flexible ADC thresholds provide rule-in and rule-out criteria for breast lesion malignancy