Ruptured gel-filled silicone breast implants: sonographic findings in 19 cases.

OBJECTIVE. The purpose of this study was to describe and illustrate the sonographic appearances of 19 ruptured silicone gel breast implants. MATERIALS AND METHODS. We retrospectively reviewed the sonograms of 16 patients with 19 ruptured silicone gel implants from two institutions. The ruptured implant was confirmed at surgery in 17 cases and by mammographic and clinical findings of a ruptured implant combined with biopsy findings of a silicone granuloma in two cases. Breast sonograms were available for review in all patients. The clinical presentation of each patient was recorded. The sonograms and mammograms were reviewed, and the findings were correlated with the surgical findings. In 16 of the 19 ruptured implants, mammographic findings suggested rupture, including lobulation of the contour of the implant and/or silicone extrusion into the breast parenchyma or axilla. In two ruptured implants, mammographic findings were normal, and in one case, no mammogram was available. In those three patients, palpable masses and clinical findings were suggestive of rupture. RESULTS. Sonography showed a unique echogenic appearance called echo-dense noise, in 17 of the 19 ruptured implants; in 10 of the 17, sonograms showed hypoechoic masses of extruded silicone also. In two ruptured implants, sonograms showed only the hypoechoic masses of extruded silicone gel. CONCLUSION. Our experience suggests that echogenic noise is a unique sonographic sign of ruptured silicone gel breast implants and may be caused by phase aberration related to the speed of sound being slower in silicone than in soft tissue.     

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.     

Human breast cancer in vivo: H-1 and P-31 MR spectroscopy at 1.5 T

To assess the potential of in vivo magnetic resonance (MR) spectroscopy for breast cancer, hydrogen-1 and phosphorus-31 MR spectra of five malignant human breast tumors were compared with those of unaffected breast tissue. The water-to-fat ratio was high in the tumors (average, 2.2) but low in the unaffected tissue (average, 0.3). The P-31 spectrum of normal breast tissue showed low levels of phosphomonoesters (PMEs), inorganic phosphate, phosphodiesters (PDEs), and ATP. In addition, an intense phosphocreatine (PCr) signal was observed in breast tissue of young women: The relative intensities of the PCr and ATP signals had a mean value of 1.9. The tumor spectrum showed elevated levels of PMEs, Pi, and PDEs, while no PCr was seen (PCr/ATP less than 0.2). In two breast cancers treated with radiation therapy, resulting in a decrease of tumor volume of more than 50%, a similar change in the tumor P-31 spectrum was observed: An intense PCr signal developed (PCr/ATP = 1.1). Control experiments indicated that the appearance of PCr after radiation therapy was the result of a radiation-induced metabolic change in the tumor itself.     

The human brain: localized H-1 MR spectroscopy at 1.0 T

Localized H-1 magnetic resonance (MR) spectroscopy of the human brain in vivo was performed at a field strength of 1.0 T. Investigations with the stimulated echo acquisition mode included studies in the right frontoparietal area, occipital lobe, cerebellum, and pons of healthy volunteers, as well as studies in two patients with astrocytomas. Prior to the acquisition of the H-1 MR spectra, all examinations included fast low angle shot MR imaging in three orientations to select the volumes of interest. The tumor spectra confirmed previous findings at higher field strengths by producing characteristic alterations from the spectra of normal brain tissue: markedly reduced resonances of N-acetyl-aspartate and creatine, increased signal intensities of cholines, and a strong resonance from lactate. The authors conclude that the results of this study clearly demonstrate the feasibility of H-1 MR spectroscopy at 1.0 T without significant losses in relative spectral resolution and signal-to-noise ratio of major metabolites with singlet resonances, compared with previous studies at 1.5 and 2.0 T.     

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.     

Bone and soft-tissue lesions: diagnosis with combined H-1 MR imaging and P-31 MR spectroscopy

The feasibility of combined magnetic resonance (MR) imaging and surface coil phosphorus-31 MR spectroscopy at 1.5 T was examined in a clinical study of 34 patients before biopsy of bone or soft-tissue lesions of the extremity and trunk. The results confirmed the inability of MR imaging alone to distinguish most benign lesions from malignant ones. Malignant lesions were distinguished from benign lesions on the basis of significantly higher mean peak ratios of phosphomonoester (PME) to beta-nucleoside triphosphate (NTP) and of phosphodiester to NTP, a significantly lower mean peak area ratio of phosphocreatine to NTP, and a higher mean pH. The diagnostic performance of the PME/NTP peak area ratio is characterized by a sensitivity (true-positive fraction) of 1.00 and a specificity (true-negative fraction) of 0.93. This study provided preliminary evidence that P-31 MR spectroscopy may be used to improve diagnostic specificity in bone and soft-tissue lesions.     

Human brain tumors: spectral patterns detected with localized H-1 MR spectroscopy.

Image-guided localized proton magnetic resonance (MR) spectroscopy of intracranial tumors was performed to correlate spectral patterns and histologic findings. Thirty-six patients were examined prior to any specific treatment. Evaluation based on signal intensity ratios showed that all tumor spectra differed from spectra of healthy brain tissue. Ratios of creatine to choline-containing compounds (Cr/Cho) and nitrogen acetyl-aspartate to Cho (NAA/Cho) were reduced significantly in all tumor spectra compared with spectra of normal tissue in contralateral brain hemispheres (P less than .005). Noncerebral tumors typically showed a vanishing or missing NAA signal, strongly reduced Cr signal, and additional signals, assigned to alanine in meningiomas and lipids in metastases. In contrast, 11 gliomas of grades 2 and 3 exhibited NAA/Cho ratios and Cr/Cho ratios that were less than normal but that were significantly larger (P less than .01) than corresponding values in eight meningiomas. Ten glioblastomas displayed spectra with various signal ratios, so no significant differences between them and other tumor types could be established. In nine gliomas a clearly detectable lactate signal was present. However, no direct correlation between lactate level and histologic tumor grading was found.     

Subacute sclerosing panencephalitis findings at MR imaging, diffusion MR imaging, and proton MR spectroscopy

A case of subacute sclerosing panencephalitis in a 2-year-old boy is reported. In addition to asymmetric lesions in the parietotemporal lobes, right thalamus, and globus pallidus, symmetric patterns were notable in the brain stem, middle cerebellar pedincles, and dentate nuclei. Proton MR spectroscopy revealed markedly decreased N-acetylaspartate peaks and normal choline and myo-inositol levels in the lesions. Diffusion MR imaging revealed an elevated diffusion pattern manifested with high apparent diffusion coefficient values (1.14-1.60 x 10(-3) mm(2)/s) compared with those in normal-appearing brain tissue (0.65-1.00 x 10(-3) mm(2)/s) and subtle high signal intensity characteristics on diffusion-weighted images obtained at b = 1000 s/mm(2).     

Inflammatory breast cancer: MR imaging findings

Purpose

This paper describes the magnetic resonance (MR) imaging features of primary inflammatory breast cancer (IBC).

Materials and methods

Two radiologists reviewed the MR examinations of 14 women with a pathological diagnosis of IBC. Images were assessed for skin thickening, oedema, nipple retraction, architectural distortion, type and extent of parenchymal and cutaneous enhancement and enhancement kinetics over time, axillary and internal mammary lymphadenopathy, pectoral muscle enhancement and additional findings.

Results

Skin thickening was identified in eight patients (58%), oedema in nine (64%), nipple retraction in two (14%), architectural distortion in eight (58%), mass-like enhancement in five (36%), non-mass-like enhancement in nine (64%) with washout enhancement curve in 12 (86%) and plateau curve in two (14%), axillary lymphadenopathy in 12 (86%) and internal mammary artery lymphadenopathy in two (14%), and pectoral muscle enhancement in one (7%). Additional findings included increased breast volume in two patients (14%), prepectoral fluid in four (28%) and hypertrophic internal mammary artery in three (21%).

Conclusions

The most characteristic MR findings of IBC are skin thickening, oedema, architectural distortion, masslike enhancement with washout curve and axillary lymphadenopathy; less frequent ones are nipple retraction, mass-like enhancement and internal mammary lymphadenopathy. Prepectoral fluid is frequent but is not a sign of infiltration.     

Screening mammography in 350 women with breast implants: prevalence and findings of implant complications.

OBJECTIVE. A series of screening mammograms in asymptomatic women with breast implants was reviewed to determine the prevalence of clinically silent sequelae of breast augmentation and to analyze the mammographic findings. MATERIALS AND METHODS. The screening mammograms of 350 consecutive women with implants were reviewed retrospectively by experienced mammographers. Any women who reported problems had a diagnostic examination and therefore were not included in our sample. Mammographic features of sequelae specific to implantation such as development of a fibrous capsule, periprosthetic calcification, implant herniation, and silicone leaks were tabulated. Additionally, modified compression (push-back) views, when obtained, were evaluated for their usefulness. RESULTS. Fibrous encapsulation of breast implants was seen in 257 (73%) of 350 women. Periprosthetic calcification was seen in 90 (26%), and 60 women (17%) had implant herniations. Sixteen women (5%) had implant failure as evidenced by silicone leak. Two of these women had bilateral implant failures. Surgical confirmation was attainable in only five of 16 women. Analysis of modified compression views demonstrated an overall improvement in visualization of breast tissue with this technique. Although the sample size is small, there was a significant increase in the amount of breast tissue seen with push-back views in women with submuscular implants. CONCLUSION. Our analysis revealed a wide range of mammographic findings in this group of asymptomatic women with breast augmentation. Especially worrisome is the 5% prevalence of unsuspected silicone extravasation. Additionally, we have demonstrated the usefulness of push-back views in this screening group, especially in women with submuscular implants.     

In vivo H-1 spectroscopy in humans at 1.5 T

Water-suppressed and section-selective proton (hydrogen-1) magnetic resonance (MR) spectra were recorded from human brain, leg muscle, liver, and heart with a 1.5-T imager. Signal from water was well suppressed, and resonances from several metabolites were consequently seen. The spectra from brains of healthy volunteers (n = 5) showed resonances from N-acetylaspartate, glutamine, aspartate, phosphocreatine/creatine, choline, taurine, and glycine. In five large brain meningiomas, resonances from N-acetyl-aspartate and phosphocreatine/creatine were either not visible or markedly decreased in intensity. The spectra from leg muscles of healthy volunteers showed resonances from protons in saturated fatty acyl chains, whereas resonances from unsaturated fatty acyl chains predominated in spectra from leg muscles of two patients with spina bifida. The spectra from livers of three healthy volunteers showed resonances from aliphatic and aromatic amino acids, choline, carnitine, and both saturated and unsaturated fatty acyl chains, and spectra from hearts of six healthy volunteers showed major resonances from phosphocreatine/creatine and taurine and smaller resonances from amino acids and fatty acyl chains.