Magnetic resonance imaging on complications of breast augmentation with injected hydrophilic polyacrylamide gel

Abstract

The injection augmentation mammaplasty for cosmetic purpose has been popular recently in China. Two kinds of injectable material are used clinically, autologous fat and biomaterial. The fat injection for breast augmentation is in question with the major problems of progressive fat re-absorption, microcalcification, and fat liquefaction.1 Now, the principal alloplastic biomaterial for injection augmentation mammaplasty in China is hydrophilic polyacrylamide gel (HPAAG). Although thousands of breasts have been augmented with HPAAG and it seems to be a good biocompatible material, some complications develop after HPAAG injection augmentation mammaplasty.2-4 The patients had to undergo surgery to remove the injected HPAAG and associated lesions. Ultrasonography or magnetic resonance imaging (MRI) should be taken preoperatively to demonstrate the distribution of injected HPAAG and associated lesions.5 In this report, the diagnostic value and clinical significance of MRI on the complications of HPAAG breast augmentation were discussed. METHODS Patients Since January 2001, 28 female patients have undertaken MRI examination after HPAAG injection for augmentation mammaplasty. Their ages ranged 24—48 years (mean age, 35 years). Definitions of HPAAG complications were observed one month postoperatively at the earliest (range one month to three years). The amount of injected HPAAG was 100—200 ml per breast. Three patients exhibited no symptoms and the other 25 patients developed various complications, including unsatisfactory contour (occurring average 3 months after injection), multiple induration or palpable lumps (occurring average 1.5 years after injection), pain on bilateral breasts, nipple sensation change. MRI examination MRI examination of 28 patients was performed by a Magneton Vision Unit (Siemens, Vision, Germany) with a field strength of 1.5 Tesla. After the informed consent was obtained and contraindications excluded, the patients were placed in the MRI unit in the prone position in order to minimize respiration artifacts. Examinations of the breasts were performed using commercially available bilateral breast surface coils in 3 steps: (1) a localizer sequence; (2) T1weighted sequence (threedimensional fast low angle shot, TE 4 ms, TR 8.1 ms, flip angle 20°, matrix 252×256, slice thickness 3.0 mm); (3) T2-weighted sequence (short inversion time inversion recovery, TE 60 ms, TR 9128 ms, TI 150 ms, flip angle 180°, matrix 157×256, slice thickness 3.0 mm). After MRI examination, the cannula aspiration or an open suction procedure had been undertaken. Capsular tissue with part of the mammary gland was excised and histopathologically examined. Two MRI specialists retrospectively evaluated the images in the course of this study independently. MRI findings were correlated with surgery findings and histopathology. RESULTS Of the 28 patients in this study, 3 cases (6 breasts) with no symptom showed normal findings on MR images, which showed half-spherical implants with smooth contour, black (low signal) on T1weighted images and bright (high signal) on T2-weighted images in the breasts (Fig. 1). One case showed an enormous cyst in lateral breast, which was confirmed a cyst filled with latex by histopathology (Fig. 2). Six cases who were unsatisfied with their asymmetry breasts and appearance showed the HPAAG injected in different layers on MR images. The site of injection HPAAG was behind the pectoral major muscle in one breast but before the pectoral major muscle in the other. In 18 cases (36 breasts), MR images showed HPAAG was extended to the subcutaneous tissue, mammary gland, major pectoral muscle, or axillary region, where many fibrous capsules around the injected HPAAG formed cystoid lumps. In most cases, the HPAAG was divided into multiple masses with a textured surface and “zebra-stripe” appearance on T2-weighted fat-suppressed MR images. The HPAAG was extended to nipple and showed a “mushroom” appearance on MR images in 1 case (Fig. 3). MR images of some patients with mastalgia showed the HPAAG was extended to the pectoral muscle, and the HPAAG in the pectoral muscle was divided into multiple masses (Fig. 4).Fig. 1.: Normal MRI findings: half-spherical implants with smooth contour, black (low signal) on T1-weighted images (A) and bright (high signal) on T2-weighted images (B) in the breasts.Fig. 2.: T2-weighted imaging showed an enormous cyst in left breast, which was confirmed a cyst filled with latex by histopathology.Fig. 3.: The HPAAG was divided into multiple masses with a textured surface and “zebra-stripe” appearance on T2-weighted fat-suppressed MR images. The HPAAG in the left breast showed a “mushroom” appearance.Fig. 4.: The HPAAG was extended to the pectoral muscle. The major pectoral muscle was disconnected on T1-weighted images (white arrow), and the HPAAG in the pectoral muscle was divided into multiple masses on T2-weighted images. A, B: Sag-T1WI; C: Tra-T2WI.Nineteen patients required cannula-suction procedures and 6 patients required open suction procedures to remove the injected HPAAG after MR examination. In the cannula aspiration or open procedure, the granular, yellow, jelly-like HPAAG was drawn out. The microscopy showed numerous macrophages and multinucleated giant cells were observed around the HPAAG capsule and in surrounding soft issue. The chronic inflammation cells infiltrated the mammary gland and capillary hypertrophy was present in the capsule, with a manifestation of foreign-body granuloma. DISCUSSION Characteristics of HPAAG HPAAG, an injectable, jelly-like, medical hydrogel, is hydrophilic, biocompatible, and anti-coagulatory. It is thought that the HPAAG is a nontoxic, nonallergenic synthetic biomaterial and is relatively safe for soft tissue augmentation up to present. HPAAG in soft tissue augmentation is adjustable in shape and size, is easy to inject through a stab-incision, and has potential clinical application.6 The HPAAG is dark on T1-weighted MR images and bright on T2-weighted MR images because of containing a large amount of water. So the HPAAG have a characteristic appearance on MR images, distinguished from the signal of mammary gland, fat and pectoral muscle. MRI is helpful to show the distribution of the HPAAG and the complications of the HPAAG injection augmentation. Complications of breast augmentation with HPAAG The complications of breast augmentation with HPAAG are varying in clinical manifestation, such as breast induration or lumps, hematoma, inflammation and infection, mastalgia, and lactation. Breast induration or lumps is the most common complication following HPAAG augmentation mammaplasty, especially in patients who are lack of subcutaneous or mammary tissue.7 The impurities or shrinkage of injected HPAAG, contraction of the fibrous capsules, poorly-distributed, or/and superficially-injected HPAAG, hematoma, and HPAAG displacement caused by early incorrect massage or trauma are contributing factors to multiple induration, nodular formation, pearl-like masses, or firm ball-like lumps. Induration masses usually present at different depths and various sizes, multiple or single, localized or diffused in breasts. Tenderness, skin color change, and asymmetry of the breasts also may be found. Mastalgia is a common symptom of myositis or myofastitis of pectoral major muscle. The surgical injury, HPAAG irritation to breast tissue or chest muscles, gel capsular contraction, hematoma, or chronic inflammation should also be considered. The pain can be aggravated with the movement of the upper extremities. When painful breasts with masses are reported, careful examination to breasts, including lymph nodes, should be undertaken for differential diagnosis of tumor, hematoma and infection.8,9 The present reports about the HPAAG injection have been flawed by a lack of randomization, absence of controls, inadequate follow-up, and undependable and incomplete clinical data. In 2 Chinese reports, the complication rates in HPAAG augmentation mammaplasty were from 1.44% to 18.26%. The induration and HPAAG-induced lumps of breasts occurred in 66.66% - 76.71% of cases with complication, but infection varied from 6.87% - 33.33% in patients with complication.1,7 The induration or lumps should be relieved by aspiration. An open procedure is advised when the aspiration of HPAAG is difficult. During the aspiration, saline irrigation and breast massage are necessary and the procedure may be repeated in some patients. The capsules containing HPAAG can be broken by blunt dissection. Value of MRI on complications of breast augmentation with HPAAG MRI can demonstrate the distribution of injected HPAAG and complications more clearly than most other modalities, particularly with respect to internal structure. Other organizing criteria could have been used to categorize breast implants, such as implant manufacturer, surface type, fill material, method of fixation, number of lumens, and so forth.10 Focusing on the MRI appearance of implants will assist radiologists when interpreting MR examinations of implants. In this report, the complication rate in HPAAG augmentation mammaplasty was 89.3%. The induration and lumps of breasts occurred in 72.0% of complication cases. In these 18 cases, MR images showed HPAAG was extended to the subcutaneous tissue, mammary gland, major pectoral muscle, and axillary region, where many fibrous capsules around the injected HPAAG formed cystoid lumps. The HPAAG was divided into multiple masses with a textured surface and “zebra-stripe” appearance on T2-weighted fat-suppressed MR images. To remove more HPAAG in breasts, the MRI offers an effective assisted method to reveal and treat complications, because the injected HPAAG location and aspiration is more precise and easier. Under local anesthesia, as an outpatients procedure, the MRI is also helpful to show the regional distribution of the HPAAG injection in the posterior mammary space, which can be expanded by local tumescent technique, to demonstrate a desired augmentation result and to minimize complications. What is more, enhanced MRI can detect and differentiate the cancers in injected breasts.11 In a word, of all the 28 patients with HPAAG injection augmentation, MRI showed the site of injection clearly, the distribution of HPAAG injection in subcutaneous tissue, posterior mammary space or in the axillary region. And it also showed whether complications occurred. MRI offers an effective method to reveal and treat complications of HPAAG injection breast augmentation.