MR imaging of extracapsular silicone from breast implants: diagnostic pitfalls.

OBJECTIVE: We sought to identify pitfalls in recognition of extracapsular silicone on MR imaging. MATERIALS AND METHODS: Three experienced observers reviewed MR images from 359 women with current (n = 320), prior (n = 15), or both current and prior (n = 24) silicone gel implants. Axial and sagittal fast spin-echo T2-weighted images with water suppression, axial inversion-recovery T2-weighted images with water suppression, and axial T2-weighted images with silicone suppression were obtained in a dedicated phased array breast coil on a 1.5-T magnet. Images were reviewed again when only one observer saw extracapsular silicone, and reasons for disagreement were recorded. RESULTS: Rupture was identified in 265 women (77%) with current silicone implants and 378 (55%) of 687 implants. Observers agreed in describing extracapsular silicone in 85 (12%) of 687 breasts with current silicone gel implants, of which 81 (95%) showed definite evidence of rupture on MR imaging. One observer reported extracapsular silicone in another 79 breasts. Confusion over contour deformity due to weakening versus breach of the capsule accounted for 33 (42%) of 79 disagreements. Another 20 (25%) of the 79 disagreements were attributed to poor conspicuity of extracapsular silicone on fast spin-echo T2-weighted images combined with intermittent observer failure to review inversion-recovery images. Subtlety of findings (n = 17, 22%) and technical issues (n = 9, 11%) with failed water suppression of pleural effusion or cysts and ghosting artifacts accounted for remaining disagreements. CONCLUSION: Extracapsular rupture is usually manifest as local spread of silicone in the breast and is not well-depicted on fast spin-echo T2-weighted images. Water-suppressed inversion-recovery T2-weighted images are often needed to identify extracapsular silicone. Distinction of the bulge in the fibrous capsule from herniation through the capsule remains problematic.     

MR imaging of silicone gel–filled breast implants in vivo with a method that visualizes silicone selectively

The lack of an adequately sensitive method for detecting silicone leakage and reported serious complications due to silicone leakage were cited as justification by the U.S. Food and Drug Administration for imposing the current restrictions on silicone gel–filled breast prostheses. The authors report a new magnetic resonance imaging method for visualizing silicone leakage: the silicone-only sequence (SOS). The method uses the conventional STIR (short-inversion-time inversion-recovery) technique combined with a 1331 radio-frequency pulse train widely used for water suppression in spectroscopy. With the SOS, silicone can be imaged while signals from fat and water are suppressed. The authors used the SOS to image phantoms and normal and ruptured silicone gel–filled breast prostheses.     

女性乳腺内置物扩散加权成像时联合应用脂肪和硅胶双重抑制的化学抑制技术

目的当进行乳腺扩散加权成像时,乳腺内的硅胶假体是技术上的挑战。我们介绍一种结合脂肪与化学抑制的方案以实现脂肪与硅胶的双重抑制,从而提高女性乳腺内置物扩散加权成像的影像质量。方法在3.0T和1.5T条件下对有硅胶假体的女性进行乳腺MR成像,单独采用STIR脂肪抑制EPI扩散加权成像和联合应用层面选择梯度反转(SSGR)技术。采用乳腺专用线圈进行成像。结果采用乳腺专用线圈,在3.0T条件下联合应用STIR和SSGR的EPI扩散加权成像可完全抑制脂肪和硅胶信号。但是,在1.5T条件下联合使用这种方法仍然可见残存的硅胶信号。然而,通过更薄的层面分割和另外的化学选择脂肪抑制(CHESS)技术可以进一步抑制1.5T条件下的硅胶信号。结论联合STIR和SSGR化学抑制技术的扩散加权成像能够消除或减低乳腺假体内的硅胶信号。     

Combination of chemical suppression techniques for dual suppression of fat and silicone at diffusion-weighted MR imaging in women with breast implants

Objectives

Silicone breast prostheses prove technically challenging when performing diffusion-weighted MR imaging in the breasts. We describe a combined fat and chemical suppression scheme to achieve dual suppression of fat and silicone, thereby improving the quality of diffusion-weighted images in women with breast implants.

Methods

MR imaging was performed at 3.0 and 1.5?T in women with silicone breast implants using short-tau inversion recovery (STIR) fat-suppressed echo-planar (EPI) diffusion-weighted MR imaging (DWI) on its own and combined with the slice-select gradient-reversal (SSGR) technique. Imaging was performed using dedicated breast imaging coils.

Results

Complete suppression of the fat and silicone signal was possible at 3.0?T using EPI DWI with STIR and SSGR, evaluated with dedicated breast coils. However, a residual silicone signal was still perceptible at 1.5?T using this combined approach. Nevertheless, a further reduction in silicone signal at 1.5?T could be achieved by employing thinner slice partitions and the addition of the chemical-selective fat-suppression (CHESS) technique.

Conclusions

DWI using combined STIR and SSGR chemical suppression techniques is feasible to eliminate or reduce silicone signal from prosthetic breast implants.

Key Points

? Breast magnetic resonance imaging (MRI) is frequently needed following breast implants ? Unsuppressed signal from silicone creates artefacts on diffusion-weighted MR sequences ? Dual fat/chemical suppression can eliminate signal from fat and silicone ? STIR with slice selective gradient reversal can suppress fat and silicone signal     

29Si imaging of silicone breast implants and intraocular silicone oil

Silicon-29 (²⁹Si) imaging was investigated as a potential imaging modality for monitoring silicone prostheses in humans. The ²⁹Si relaxation times of several silicone gels were measured and found to average T₁ = 21.2 ± 1.5 s and T₂ = 207 ± 40 ms, with no significant difference between virgin and explanted gels. A single-shot half-Fourier rapid acquisition with relaxation enhancement (RARE) and a refocused gradientecho sequence were used for acquiring ²⁹Si images with 5 × 5 mm² resolution and no slice selection. Three volunteers with silicone-gel-filled breast implants and one subject with an intraocular silicone oil injection were thus examined in a total acquisition time of 10–15 min per image. On all ²⁹Si images, the shape of the silicone object was well depicted. Although at present, conventional proton images are superior in resolution and signal-to-noise ratio, ²⁹Si imaging has the advantage of optimal specificity, since only the silicone itself is visible.     

乳房假体植入后破裂及泄漏的MRI表现

目的：探讨磁共振诊断乳房假体破裂和（或）泄漏的临床价值。方法：对17例隆乳术后患者行MR扫描，对1个体外正常硅胶液硅胶囊袋假体行相同序列MR扫描作为正常参照。对囊袋假体及注射聚丙烯酰胺假体的MR表现进行分类分析。结果：正常硅胶囊袋单腔假体7例12个，其中4例8个囊内为硅胶液；3例4个囊内为生理盐水。生理盐水硅胶囊袋单腔假体破裂2例2个，其中1 个属囊内破裂，MRI示残留塌陷的硅胶囊袋呈长条状长T1、短T2信号；另1个属囊外破裂，MRI示假体内有多条丝状短T2低信号，即“条丝征”，同侧乳房外见假体内容物颗粒。注射聚丙烯酰胺假体10例20个，其中1例2个完整；8例16个完全破裂，表现为多发条块状、结节状长T1、长T2信号，8例中有7例见双侧乳房腺体内及乳房外有注射物颗粒；1例2个内部撕裂，MRI表现为假体内有多发“条丝征”。结论：MR检查可明确乳房假体的类型、位置；明确假体破裂类型及漏出物的分布范围；因此能为临床手术提供准确定位，为随访复查提供客观资料。     

乳房假体破裂及注射水凝胶扩散的磁共振成像

目的 :探讨乳房假体破裂及注射聚丙烯酰胺水凝胶扩散的MRI表现及临床意义。方法 :对 18例隆乳术后患者行MR扫描 ,并与术中所见比较。对假体置入及注射聚丙烯酰胺水凝胶的MRI表现进行分类分析。结果 :正常单腔硅凝胶假体 9例 ;单腔硅凝胶假体纤维囊内破裂 13例 ,MRI示假体内有多发条丝状短T2 低信号 ,即“条丝征” ;单腔硅凝胶假体纤维囊外破裂 2例 ,MRI示乳房腺体内长T2 结节状内容物颗粒。正常聚丙烯酰胺水凝胶注射 3例 ,注射聚丙烯酰胺水凝胶扩散 9例 ,MRI示乳腺后间隙以外部位出现结节状长T1、长T2 信号。结论 :MRI可诊断乳房假体有无破裂或注射聚丙烯酰胺水凝胶有无扩散 ,可明确其漏出或扩散的范围 ,因此能为手术提供准确定位 ,为随访提供客观资料。     

MR imaging of silicone breast implants: Evaluation of prospective and retrospective interpretations and interobserver agreement

MR imaging was used to evaluate the integrity of silicone breast implants in 54 women with 108 implants. MR images were interpreted by relatively inexperienced readers who tried to reproduce the experiences reported in the literature. The study examines the interobserver agreement using different diagnostic signs and the influence of experience on interpretation errors. Prospective and retrospective interpretations were compared with surgical findings at the time of explantation. Diagnostic indicators, including the linguine sign, the inverted tear drop sign, the C sign, water droplets mixed with silicone, and extracapsular globules of silicone, were evaluated for diagnostic efficacy and interobserver agreement. The prospective sensitivity and specificity were 87% and 78%, respectively. With the retrospective interpretations, the sensitivity and specificity increased to 93% and 92%, respectively. Most of the prospective false-positive interpretations were due to misinterpreting radial folds as signs of implant rupture. Six implants interpreted retrospectively as false positives had gross amounts of silicone around the implants at surgery but there were no obvious rents in the implant shells. There was fair to excellent interobserver agreement with the individual diagnostic signs except for extracapsular globules of silicone. All of the signs had specificities of greater than 90%. The sensitivities of the individual signs were less than the overall retrospective sensitivity. With experience, the sensitivity improved from 87% to 93% and the specificity improved from 78% to 92%. This study helps substantiate the use of diagnostic signs used by other authors to detect silicone loss from breast implants by MR imaging; however, questions remain as to the clinical role of MR imaging in evaluating implants for silicone loss.     

Phantom evaluation of imaging modalities for silicone breast implants.

RATIONALE AND OBJECTIVES. Recent concern regarding possible adverse effects from silicone breast implants has increased the role of radiologists in assessing augmented breasts. The authors compare the commonly available imaging modalities in evaluating the intact silicone implant as well as free silicone in the adjacent tissue. METHODS. A contrast resolution phantom and breast of veal phantom were tested. Fat was used as a reference material. The phantoms were imaged with xeromammography, film-screen mammography, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). Proton MRI spectroscopy also was performed on fat, silicone, water, and water/gelatin samples. The consensus of two radiologists determined whether free silicone was present. RESULTS. CT and MRI provided the best images of the implant and the free silicone. Several features of MRI were useful: spin-density scans and the fast low-angle shot (FLASH) and fast imaging with steady-state precision (FISP) techniques provided excellent resolution, a consistent chemical shift artifact appeared around the silicone, and frequency selective pre-saturation techniques resulted in marked suppression of the silicone. CONCLUSION. Additional testing in a more realistic setting, breast coil design, and improvement of various MRI techniques, particularly the frequency selective pre-saturation techniques, all appear promising in evaluating breast implants, the presence of free silicone, and the adjacent tissues.     

Silicone breast implants in vivo: MR imaging.

This study was designed to evaluate pulse sequences and patient positioning for MR imaging of silicone breast implants in patients. One hundred forty-three patients (281 silicone implants) underwent imaging over a 21-month period. The combination of a T2-weighted fast spin echo technique (SE), T2-weighted fast SE with water suppression, and T1-weighted SE with fat suppression is recommended to reliably differentiate silicone from other breast tissues and to identify intracapsular and extracapsular ruptures or leaks. Seventy of the 143 patients underwent removal of their silicone implants. The sensitivity for detection of silicone implant rupture was 76%, with a specificity of 97%. Positioning the patient prone improved image quality.     

有胸部辐射史妇女的乳腺MRI筛查

目的对有胸部射线辐射史的妇女行MRI筛查以检测隐匿性乳腺癌。材料与方法本实验符合HIPAA规定,通过机构伦理委员会审核,无需知情同意书。回顾性研究     

MR imaging of the ipsilateral breast in women with percutaneously proven breast cancer

OBJECTIVE: The purpose of this study was to review MR imaging findings in the ipsilateral breast in women with percutaneously proven breast cancer. MATERIALS AND METHODS: Retrospective review was performed of records of 70 consecutive women with percutaneously proven unilateral breast cancer who were considered candidates for breast conservation surgery and who had preoperative MR imaging of the ipsilateral breast. MR images and medical records were reviewed. RESULTS: MR imaging identified mammographically and clinically occult cancer other than the index lesion in the ipsilateral breast in 19 women (27%), including infiltrating cancer in 11 women (16%) and ductal carcinoma in situ in eight women (11%). These additional sites of cancer were in the same quadrant as the index cancer in 14 women (20%), in a different quadrant in three women (4%), and in both the same and different quadrants in two women (3%). Additional sites of cancer were more likely in women with, rather than in those without, a family history of breast cancer (42% vs 14%, p < 0.02) and in women whose index cancer was infiltrating lobular rather than other histologies (55% vs 22%, p < 0.06). In 17 women (24%), MR imaging detected ipsilateral lesions that were benign. Changes due to prior percutaneous biopsy were infrequently observed on MR images and included a clip in 12 women (17%) and a small hematoma in two women (3%). CONCLUSION: MR imaging identified additional sites of ipsilateral cancer in 27% of women with percutaneously proven breast cancer. The yield was highest in women with a family history of breast cancer or infiltrating lobular histology in the index cancer. Change after biopsy was infrequent and did not interfere with the MR imaging interpretation.     

原位小叶癌史妇女的乳腺MRI筛查

目的评价MRI筛查对原位小叶癌史的妇女隐匿性乳腺癌的检测作用。材料与方法该符合HIPAA标准的研究获机构审查委员会批准,无需知情同意。回顾性分析资料库获得2003年1月—2008年9月间220例原位小叶癌史     

MR imaging findings in the contralateral breast of women with recently diagnosed breast cancer

OBJECTIVE: The purpose of this study was to determine the frequency and positive predictive value of biopsy performed on the basis of MR imaging findings in the contralateral breast in women with recently diagnosed breast cancer. MATERIALS AND METHODS: We performed a retrospective review of records of 1336 consecutive breast MR imaging examinations over a 2-year period. Of these examinations, 223 imaged the asymptomatic, mammographically normal contralateral breast in women whose breast cancer was diagnosed within 6 months preceding MR imaging. Records of these 223 examinations were reviewed to determine the frequency of recommending contralateral breast biopsy and the biopsy results. RESULTS: Contralateral breast biopsy was recommended in 72 (32%) of 223 women and performed in 61 women. Cancer occult to mammography and physical examination was detected by MR imaging in 12 women, constituting 20% (12/61) of women who underwent contralateral biopsy and 5% (12/223) of women who underwent contralateral breast MR imaging. Among these 12 cancers, six (50%) were ductal carcinoma in situ (DCIS) and six (50%) were infiltrating carcinoma. The median size of infiltrating carcinoma was 0.5 cm (range, 0.1-1.0 cm). Contralateral biopsy revealed benign (n = 31) or high-risk (n = 18) lesions in 49 women, constituting 80% (49/61) of women who underwent contralateral biopsy and 22% (49/223) of women who underwent contralateral MR imaging. CONCLUSION: In women with recently diagnosed breast cancer, MR imaging of the contralateral breast led to a biopsy recommendation in 32%. Cancer was found in 20% of women who underwent contralateral breast biopsy and in 5% of women who underwent contralateral breast MR imaging.