Value of contrast-enhanced MRI of breast after silicone implant

Summary Early recognition of recurrence and work-up of clinically indeterminate lesions may be impaired after reconstruction with silicone implants due to superimposition of the implant or to scarring. This study was undertaken to evaluate the use of contrast-enhanced MRI in patients with silicone implant after breast cancer. Contrast-enhanded MRI was offered to 169 patients. Comparative two- to three-view mammography was also performed in 169 patients, as well as comparative sonography in 144 patients. Conventional imaging and clinical examination detected only 8/13 recurrences, whereas 12/13 were detected by MRI. One recurrence had been visible as a strongly enhancing 2-mm dot in a previous examination (2 years before), but was not called. It was therefore counted as false negative. In addition, multicentricity was detected by MRI alone in two of three cases. MRI correctly diagnosed scar tissue in all cases with indeterminate findings. However, due to false-positive calls caused by enhancing granulomas specificity could not be improved. Contrast-enhanded MRI allowed decisive additional information in our study group and improved the sensitivity significantly (concerning all diagnoses). Contrast-enhanded MRI is recommended in patients with diagnostic problems or high risk of recurrence after silicone implants.      

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.     

Intrathoracic migration of a silicone breast implant 5 months after video-assisted thoracoscopic surgery

A 72-year-old woman, who had previous bilateral reconstruction mammoplasty, underwent video-assisted thoracoscopic surgery for a right middle lobe pulmonary carcinoid. Five months after her surgery, the patient noticed an acute pronounced reduction in her right breast volume, with shortness of breath and cough. A computed tomography study of the chest revealed intrathoracic migration and rupture of her right breast implant, with associated silicone thorax. Subsequent video-assisted thoracoscopic surgery confirmed this diagnosis.     

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.     

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.     

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.     

Cardiac imaging

The emergence of noninvasive imaging techniques for the definitive diagnosis and monitoring of cardiovascular disease has greatly altered cardiac imaging in the past 25 years. The practice of cardiac imaging in 1975 was centered on conventional radiography and angiography, but, in the past 2 decades, noninvasive techniques have substantially replaced catheterization and angiography. The reliance on echocardiography for the evaluation of many cardiac diseases had a profoundly negative influence on the role of the radiologist in cardiac imaging, since the exercise of this modality has been a nearly exclusive province of the cardiologist. However, in the past decade, magnetic resonance imaging has been gradually assuming more importance in cardiovascular diagnosis; with this increase in importance, the role of the radiologist has been reactivated. In 1975, fellowship training in cardiac imaging was frequently combined with training in angiography. Now, training may be more effective by combining cardiac and pulmonary imaging in a thoracic imaging fellowship, but cross-training with an associated subspeciality will be influenced by priorities and personnel in various departments.