Pharmacokinetic mapping for lesion classification in dynamic breast MRI

Purpose:

To prospectively investigate whether a rapid dynamic MRI protocol, in conjunction with pharmacokinetic modeling, could provide diagnostically useful information for discriminating biopsy‐proven benign lesions from malignancies.

Materials and Methods:

Patients referred to breast biopsy based on suspicious screening findings were eligible. After anatomic imaging, patients were scanned using a dynamic protocol with complete bilateral breast coverage. Maps of pharmacokinetic parameters representing transfer constant (K^trans), efflux rate constant (k_ep), blood plasma volume fraction (v_p), and extracellular extravascular volume fraction (v_e) were averaged over lesions and used, with biopsy results, to generate receiver operating characteristic curves for linear classifiers using one, two, or three parameters.

Results:

Biopsy and imaging results were obtained from 93 lesions in 74 of 78 study patients. Classification based on K^trans and k_ep gave the greatest accuracy, with an area under the receiver operating characteristic curve of 0.915, sensitivity of 91%, and specificity of 85%, compared with values of 88% and 68%, respectively, obtained in a recent study of clinical breast MRI in a similar patient population.

Conclusion:

Pharmacokinetic classification of breast lesions is practical on modern MRI hardware and provides significant accuracy for identification of malignancies. Sensitivity of a two‐parameter linear classifier is comparable to that reported in a recent multicenter study of clinical breast MRI, while specificity is significantly higher. J. Magn. Reson. Imaging 2010;31:1371–1378. © 2010 Wiley‐Liss, Inc.     

Usefulness of breast-specific gamma imaging as an adjunct modality in breast cancer patients with dense breast: a comparative study with MRI

Objective  

The aim of this study was to evaluate the adjunctive benefits of breast-specific gamma imaging (BSGI) versus magnetic resonance imaging (MRI) in breast cancer patients with dense breasts.     

Role of diffusion-weighted imaging as an adjunct to contrast-enhanced breast MRI in evaluating residual breast cancer following neoadjuvant chemotherapy

Objective

To investigate whether the addition of diffusion-weighted imaging (DWI) to dynamic contrast-enhanced MRI (DCE-MRI) improves diagnostic performance in predicting pathologic response and residual breast cancer size following neoadjuvant chemotherapy.

Materials and methods

A total of 78 consecutive patients who underwent preoperative breast MRI with DWI following neoadjuvant chemotherapy were enrolled. DWI was performed on a 1.5 T system with b values of 0 and 750 s/mm. or on a 3 T system with b values of 0 and 800 or 0 and 1000 s/mm. The images on DCE-MRI alone, DWI alone, and DCE-MRI plus DWI were retrospectively reviewed. We evaluated the diagnostic performances of the three MRI protocols for the detection of residual cancer. The tumor size as predicted by MRI was compared with histopathologic findings. Apparent diffusion coefficient (ADC) values were also compared between the groups with and without residual cancer.

Results

Of the 78 patients, 59 (75.6%) had residual cancer. For detection of residual cancer, DCE-MRI plus DWI had higher specificity (80.0%), accuracy (91.0%), and PPV (93.2%) than DCE-MRI or DWI alone (P = 0.004, P = 0.007, and P = 0.034, respectively). The ICC values for residual cancer size between MRI and histopathology were 0.891 for DCE-MRI plus DWI, 0.792 for DCE-MRI, and 0.773 for DWI. ADC values showed no significant differences between residual cancer and chemotherapeutic changes (P = 0.130).

Conclusions

The addition of DWI to DCE-MRI significantly improved diagnostic performance in predicting pathologic response and residual breast cancer size after neoadjuvant chemotherapy.     

重视MRI在乳腺疾病中的重要作用

1991年,美国食品药物管理局(FDA)通过决议,认同磁共振成像可以作为乳腺X线成像技术的辅助手段应用于临床。自此,MRI作为一种崭新的乳腺疾病检查方法在全球范围内逐渐得以推广应用。而且,随着这种应用的进一步深入开展,MRI在乳腺疾病的检出和诊断领域中迅速地显示出了无可比拟的独到的优越性!首先,MRI具有极高的组织分辨力,即使对微小病灶也颇为敏感,可以显示其它检查手段不能检出的乳腺疾患。这一优势,在诸多的超声、X线钼靶摄片检查中仅发现1个小的乳腺癌病灶而MRI则显示为多发乳腺癌的病例中得到了充分的证实。人们已不再对临床触…     

Interventional MRI of the breast: lesion localisation and biopsy

With the growing use of breast MRI an increasing need exists for reliable MR-guided preoperative localisation or even MR-guided needle biopsy. In this article an overview is given of the different approaches and the present state of the art. With closed magnets the following approaches have been made: freehand localisation (similar to CT-guided freehand localisation), and freehand localisation combined with a frameless stereotaxic system operating with support by ultrasound. One localisation device for supine localisation and a thermoplastic mesh for breast stabilisation have been reported. Most investigators have used compression devices to immobilise the breast and prevent shift during needle insertion. Thus far, one immobilisation and aiming device has been designed for open magnets. A small number of experiences exist with interventions on open MR units using a navigation system. Wire localisations are presently a well-established procedure. Magnetic-resonance-guided needle biopsy has been accomplished in closed systems as well as by the use of breast immobilisation devices. However, problems still exist due to severe needle artefacts, tissue shift during the intervention and fast equalisation of contrast enhancement in lesions with surrounding tissue. Therefore, needle biopsy is not recommended for lesions < 10 mm. Magnetic-resonance-guided vacuum biopsy is somewhat more invasive but promises to solve most of these problems.     

Gadolinium-enhanced dynamic MRI of breast hemangioma

We describe a patient with hemangioma of the breast. The tumor showed an Ill-defined hypointense mass on T1-weighted imaging and hyperintense mass on T2-weighted imaging. After bolus gadolinium injection, the tumor showed heterogeneous enhancement in early phase and in the time-intensity an early intensive enhancement was followed by a plateau. This intensive enhancement in the early phase is not limited to breast carcinoma but can be found in breast hemangiomas as well.     

Apparent diffusion coefficient values as an adjunct to dynamic contrast enhanced MRI for discriminating benign and malignant breast lesions presenting as mass and non-mass like enhancement

Purpose

The purpose of our study was to evaluate the diagnostic value of an imaging protocol that combines dynamic contrast-enhanced MRI (DCE-MRI) and apparent diffusion coefficient (ADC), measured by diffusion weighted MRI, in discriminating benign and malignant breast lesions presenting as mass and non mass like enhancement (NMLE).

Methods and materials

80 patients with 110 breast lesions identified with dynamic contrast MRI. Diffusion-weighted images were obtained at b values of 0 and 750 S/mm², differences in the apparent diffusion coefficients (ADCs) are included in the study and malignant lesions were compared by lesion type (mass or NMLE), and the analysis was performed to evaluate diagnostic performance based on ADC thresholds. All lesions have pathological results. The study has been done retrospectively 50 patients underwent surgical excision with preoperative localization, while the 30 cases underwent stereotactic biopsies either US or mammographically guided techniques specially if associated with micro calcifications.

Results

The mean ADC value of all benign lesions is 1.41 ± 0.36 × 10⁻³ mm²/s, which is higher than the mean ADC of all malignant lesions (1.05 ± 0.30 × 10⁻³ mm²/s, p < 0.05). In the MASS type, the mean ADC is higher in the benign group (1.34 ± 0.30 × 10⁻³ mm²/s) than in the malignant group (1.02 ± 0.29 × 10⁻³ mm²/s, p < 0.01). In the NMLE type, the mean ADC is also higher in the benign group (1.54 ± 0.45 × 10⁻³ mm²/s) than in the malignant group (1.11 ± 0.32 × 10⁻³ mm²/s, p < 0.01). Therefore, benign lesions have higher ADC values than malignant lesions, regardless of the lesion morphology.

Conclusion

Diffusion-weighted MRI shows adequate help in differentiation of benign and malignant masses and lesions with non-mass like enhancement found at breast MRI.     

乳腺肿瘤的MRI扩散特征及参数选定

目的探讨MR扩散加权成像（DWI）不同扩散敏感因子（b）值对鉴别乳腺良恶性病变的价值。方法测定83例患者95个乳腺病变在b值分别取500、1000、2000s／mm^2时的表观扩散系数（ADC）值和信号强度，以手术后病理结果为金标准，比较同一b值时不同乳腺病变、以及不同b值时同一种病变平均ADC值和信号强度的差异。结果（1）乳腺病变分为乳腺癌、良性病变和囊肿。各种病变的平均ADC值、平均信号强度在不同b值时不同，其中乳腺癌在b=500s／mm^2时分别为1．375±0．378和839．713±360．493（与其他病变比较，F值分别为16．019、30．409，P均〈0．01）；b=1000s／mm^2时分别为1．176±0．311和459．314±229．609（与其他病变比较，，值分别为16．578和23．092，P均〈0．01）．b=2000s／mm^2时分别为0．824±0．198和243．825±110．616（与其他病变比较，F值分别为3．122、23．888，P值分别〈0．05和〈0．01）。各种乳腺病变两两比较显示在b=500和1000s／mm^2时，大部分病变之间平均ADC值差异有统计学意义，而在b=2000s／mm^2时仅在乳腺癌和良性病变间差异有统计学意义。（2）以各b值时乳腺癌平均ADC95％可信区间的上限作为确定乳腺癌的上限阈值点，取这些阈值点在b值=500、1000、2000s／mm^2时确定乳腺癌的诊断指标，敏感性分别为70．92％、70．73％、69．77％，特异性分别为77．19％、75．70％、54．76％，准确性分别为77．12％、74．32％、62．35％。ROC曲线分析曲线下面积（Az）500=0．775±0．046，Az1000=0．780±0．044，P均〈0．01，提示b取500和1000s／mm^2时对诊断乳腺癌有统计学意义。而Az2000=0．620±0．062，P〉0．05，提示b=2000s／mm^2对鉴别乳腺良恶性病变差异无统计学意义。结论b值取500和1000s／mm^2的MRDWI可以用于鉴别乳腺良恶性病变。     

CTLM as an adjunct to mammography in the diagnosis of patients with dense breast

PurposeThe purpose was to evaluate the utility of computed tomographic laser mammography (CTLM) as an adjunct examination to mammography in women with dense breast tissue.MethodsWe retrospectively compared the findings of mammography, CTLM, and adjunct CTLM to mammography with pathology of 155 women scheduled for biopsy or surgery.ResultsPositive lesions were observed more significantly in malignant than benign lesions. The sensitivity of mammography vs. mammography+CTLM was 34.4% vs. 81.57% among extremely dense breasts and 68.29% vs. 95.34% among heterogeneously dense breasts.ConclusionCTLM could distinguish benign lesions from malignant lesions and is not affected by breast density.     

Diagnosis of breast cancer: contribution of US as an adjunct to mammography.

PURPOSE: To determine the value of ultrasonography (US) as an adjunct to mammography for the diagnosis of breast cancer. MATERIALS AND METHODS: In a 2-year prospective study, 4,811 mammograms were classified according to level of suspicion of malignancy. Targeted US was performed to analyze (a) circumscribed lesions, possibly cysts; (b) palpable lesions visible at mammography; (c) palpable lesions not visible at mammography; and (d) nonpalpable lesions visible at mammography. After US was performed in 1,103 cases (23%), cases were reclassified for level of suspicion. RESULTS: In 338 cases, breast cancer was diagnosed. The sensitivity of mammography for all 4,811 cases was 83%; the specificity was 97%. After US, the combined sensitivity increased to 91%, with a specificity of 98%. The increase was significant (P < .001). The increase in sensitivity was highest among women younger than 50 years. The positive predictive value for mammography was high (72%), which reflects a high threshold for biopsy; this may have augmented the yield of US. CONCLUSION: The use of US as an adjunct to mammography resulted in an increase in diagnostic accuracy. Its contribution to the diagnosis of breast cancer in this study was 7.4%.     

Usefulness of 3D-VIBE method in breast dynamic MRI: imaging parameters and contrasting effects

MR imaging (MRI) has been reported to be a useful modality to characterize breast tumors and to evaluate disease extent. Contrast-enhanced dynamic MRI, in particular, allows breast lesions to be characterized with high sensitivity and specificity. Our study was designed to develop three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) techniques for the evaluation of breast tumors. First, agarose/Gd-DTPA phantoms with various concentrations of Gd-DTPA were imaged using 3D-VIBE and turbo spin echo (TSE). Second, one of the phantoms was imaged with 3D-VIBE using different flip angles. Finally, water excitation (WE) and a chemical shift-selective (CHESS) pulse were applied to the images. Each image was analyzed for signal intensity, signal-to-noise ratio (1.25*Ms/Mb) (SNR), and contrast ratio [(Ms1-Ms2)/[(Ms1+Ms2)/2]]. The results showed that 3D-VIBE provided better contrast ratios with a linear fit than TSE, although 3D-VIBE showed a lower SNR. To reach the best contrast ratio, the optimized flip angle was found to be 30 degrees for contrast-enhanced dynamic study. Both WE and CHESS pulses were reliable for obtaining fat-suppressed images. In conclusion, the 3D-VIBE technique can image the entire breast area with high resolution and provide better contrast than TSE. Our phantom study suggests that optimized 3D-VIBE may be useful for the assessment of breast tumors.     

In vivo diffusion-weighted MRI of the breast: potential for lesion characterization

PURPOSE: To investigate the potential of apparent diffusion coefficients (ADCs) in characterizing breast lesions in vivo.MATERIALS AND METHODS: Two diffusion-weighted (DW) sequences were implemented on a 1.5 Tesla scanner, with low b-value orthogonal and high b-value tetrahedral sensitized sequences. The orthogonal sequence was evaluated on 16 normal volunteers and 23 patients with known lesion types (six benign and 17 malignant). The tetrahedral sequence was evaluated on a smaller number of subjects: two normal, two malignant, and two benign.RESULTS: The mean value of the ADC of the malignant tumors was reduced compared to that of the benign lesions and normal tissue. This finding was related to the increased cellularity of the malignant lesions. The ADC values were elevated for all tissue types with the low b-value sequence as compared to the high b-value sequence, indicating contributions from perfusion effects at the low b-values.CONCLUSION: The study clearly shows that DW-MRI can help characterize breast lesions in vivo.     

Improvement in breast lesion characterization with dynamic contrast-enhanced MRI using pharmacokinetic modeling and bookend T(1) measurements.

Dynamic contrast-enhanced breast MR imaging was performed on 14 patients (five cancerous lesions, nine benign) with slice-selective spoiled gradient-recalled echo (2D SPGR) imaging. Adiabatic saturation recovery T(1) measurements were performed before (T(1pre)) and after (T(1post)) 2D SPGR imaging. These two "bookend" T(1) measurements were used to calibrate the equations which were employed to convert the time course of the 2D SPGR signal strength to T(1)-vs.-time, which in turn was used to compute the gadolinium concentration-vs.-time ([C](t)) in the lesion. The extraction-flow product (EF) was computed for each lesion by pharmacokinetic modeling of [C](t). For this study, EF provided a sensitivity and specificity for cancer of 100% and 78%, respectively. When only T(1pre) was used to estimate [C](t) (which assumes a priori knowledge of the shape and amplitude of the slice profile), the sensitivity and specificity fell to 80% and 56%, respectively. This is presumably due to unexpected variations in the shape and/or amplitude of the slice profile, which could be caused by factors such as patient-to-patient variations in breast geometry or inconsistently set transmit gains. Therefore, both T(1pre) and T(1post) measurements are necessary for optimum sensitivity and specificity using pharmacokinetic analysis.     

Diffusion-weighted MRI as an adjunct to mammography in women under 50 years of age: an initial study

Purpose:

To evaluate diffusion‐weighted magnetic resonance (DW) imaging as an adjunct to mammography for the detection of small invasive breast cancer.

Materials and Methods:

Institutional review board standards were followed for this retrospective study. We performed both breast DW imaging and mammography on 25 women under 50 years of age with pathologically proven T1 breast cancer and on 21 healthy women under 50 years of age. Four offsite radiologists blind to the clinical information independently interpreted the mammograms and DW images and then classified their confidence level regarding the presence of breast cancer. The composite area under receiver operating characteristic curve (AUC), of mammography alone, DW imaging alone, and the combination of DW imaging and mammography (DWI/Cal) were calculated.

Results:

The AUC of composite ROC curves of mammography, DW imaging, DWI/Cal combination, was 0.79 (95% CI, 0.72–0.87), 0.86 (95% CI, 0.84–0.87), and 0.96 (95% CI, 0.92–1.00), respectively.

Conclusion:

DW imaging may be a useful adjunct to mammography in the detection of small invasive breast cancer in women under 50 years of age. J. Magn. Reson. Imaging 2012;36:139–144. © 2012 Wiley Periodicals, Inc.     

MRI as an adjunct to echocardiography for the diagnostic imaging of cardiac masses

Nine patients underwent magnetic resonance imaging (MRI) as part of the diagnostic evaluation for cardiac masses; eight of them had been preliminarily studied by 2D-echocardiography (US). MRI did not add to the US diagnostic information in patients affected by intracavitary masses. It represented the definitive diagnostic modality in two patients with intramural pathology: one with ventricular rhabdomyoma, the second with an echinococcyal cyst located within the left atrial wall. The complementary role of MRI to US in cardiac masses is discussed.     

Morel-Lavallee lesion in an adolescent with ultrasound and MRI correlation

The Morel-Lavallee lesion is a serous collection in the region of the greater trochanter, resulting from a closed degloving injury at the deep fascial interface. Imaging demonstrates characteristic appearance in relation to this lesion, differentiating it from other mass lesions. We report a case of Morel-Lavallee lesion in an adolescent, with ultrasound and MRI correlation.     

乳腺癌MR动态增强扫描定量分析及其临床应用

对于乳腺癌的检出,乳腺MR成像被认为是一种具有高敏感性和较高特异性的检查方式.动态增强MRI定量分析可以通过Ktrans、kep、ve等多种参数的应用,量化评价肿瘤组织的血管内皮通透性和血流量.其较半定量分析能更为准确、客观地诊断肿瘤的良恶性及评价治疗疗效.就应用动态增强MRI定量分析乳腺癌的现状及目前所存在的问题作一综述.     

乳腺X线摄影与MRI对致密型乳腺内病变的诊断

目的:比较乳腺X线摄影与MRI对致密型乳腺病变的诊断价值.方法:搜集同时行乳腺X线摄影及MRI检查的致密型乳腺患者185例,所有病例均经病理证实,分别分析两种方法的影像学表现,并与病理对照.结果:185例患者中组织病理学为恶性者80例,良性105例.乳腺X线摄影诊断致密型乳腺恶性病变的敏感度、特异度、阳性预测值及阴性预...