contents TIB Abstract Breast MR imaging is the most accurate imaging investigation to detect breast prosthesis rupture. Rupture is common in older prostheses (> 10 years post implanta- tion) and is often asymptomatic. The radi- ological signs of rupture are due to collapse of the elastomer shell which is eneveloped by silicone gel and when the silicone gel separates the elastomer shell from the sur- rounding fibrous breast capsule. Introduction Breast implantation using prostheses is becoming a common plastic surgical proce- dure in this country. In the USA between 1 and 2 million women have had breast implantation procedures.1 The main rea- sons for implantation are breast recon- struction following breast cancer surgery or augmentation for cosmetic reasons. However complications following implan- tation of prostheses are common, occur- ring in 24% of patients in a series of 749 patients treated at the Mayo Clinic.1 Complications are difficult to detect by pal- pation, or even with ultrasound or mam- mographic examinations.2-4 They include rupture or leaking of silicone gel from the prosthesis and the development of silicone granulomas. Ruptured prostheses occur in 23 - 65% of patients and are usually silent.5 Breast MR is both sensitive and specific in detecting complications following prosthe- sis insertion. In this review we illustrate the utility of breast MR imaging in detecting these com- plications. Breast prostheses Prostheses consist of a silicone-elas- tomer bag filled with saline, or previously with silicone gel. Currently in the USA only saline is used to fill the prostheses because of the complications associated with sili- cone gel rupture.1 The new generation of prostheses are manufactured with stronger and thinner capsules, so preventing rup- ture. Complications associ- ated with breast implantation Complications can be classified into those associated with the surgical proce- dure and those associated with the prosthe- sis itself. Wound complications include the development of a haematoma, seroma, wound infection, and wound dehiscence.6 Implant complications include rupture or leakage and capsular contrac- tion by the surrounding scar fibrosis result- ing in loss of the normal breast shape and consistency.6 Implant rupture or valve/port failure appears to be a function of the age of the prosthesis.1 In a large community-based prospective study of 344 patients in the USA, 55% of patients had MR evidence of rupture with silicone gel, evident outside the elastomer shell in 21% of patients.7 Rupture is very common 10 years after implantation.7 The prosthesis must be removed once the diagnosis of rupture is made. Capsular contraction results from a scar forming around the shell and requires re-operation in 5 - 20% of all patients implanted. Capsular contraction is the commonest cause of patient dissatisfaction and the commonest cause of replacement of the prosthesis. Older prostheses contained silicone gel. Rupture of these prostheses, although asymptomatic in most patients, has been associated with collagen vascular disorders and chronic fatigue syndrome. However more current data disputes any of these associations. Currently there is debate on whether all the migrated silicone gel requires removal or not. Detection of rupture is inaccurate with mammography and ultrasound examina- tion. The prosthesis contents usually obscure the surrounding breast parenchy- ma making detection of a leak extremely difficult. MR imaging of the breast using a phased array local breast coil has been demonstrated to be the most sensitive and specific investigation to detect rupture. In large series7,8 sensitivity for ruptured pros- theses was from 74% to 94%, with a speci- ficity of 85 - 98%. Breast MR imaging signs of rupture Breast MR technique consists of both T1 and T2-weighted spin echo transverse and sagittal images, a T1-weighted trans- verse image with fat saturation, a T2- weighted STIR sequence, and a turbo inver- sion recovery T1 transverse (TIRM) sequence with fluid suppression to detect silicone migration. The TIRM sequence suppresses fluid so making displaced sili- cone gel more visible. A phased array local breast coil is essential. There are essentially two signs of rup- ture detectable with breast MR. The first sign is when the elastomer shell collapses and is enveloped by the silicone gel and this is detected as collapsed low-intensity lines internal to the high-intensity gel (Figs 1 and 2). The second sign is when silicone gel separates the elastometer shell from the fibrous capsule of breast tissue or the gel is found outside the shell within the breast tissue (Fig. 3). Various radiological descrip- tions are associated with these two signs, 7 SA JOURNAL OF RADIOLOGY • October 2005 REVIEW ARTICLE Magnetic resonance imaging of breast prostheses P Corr FFRad (D) SA P Seolall Nat Dip Rad (D) H Booth Nat Dip Rad (D) Department of Radiology Nelson Mandela School of Medicine and Inkosi Albert Luthuli Hospital Durban pg7-8 9/28/05 1:22 PM Page 7 such as the linguine sign, double wavy sign, key hole sign, noose sign, and inverted tear drop sign.7 Conclusions Breast MR imaging is a reliable and accurate investigation to detect the compli- cation of breast prosthesis implantation. Rupture of implants is common and often asymptomatic and appears to be dependent on the age of the prosthesis. References 1. Gabriel SE, Woods JE, O'Fallon WM, Beard CM, Kurland LT, Melton LJ. Complications leading to surgery after breast implantation N Engl J Med 1997; 336: 677-682. 2. Ahn CY, DeBruhl ND, Gorczyca DP, Shaw WW, Bassett LW. Comparative silicone breast implant evaluation using mammography, sonography, and magnetic resonance imaging: experience with 59 implants. Plast Reconstr Surg 1994; 94: 620 -627. 3. Reynolds HE, Buckwalter KA, Jackson VP, Siwy BK, Alexander SG. Comparison of mammography, sonography and MR imaging in the detection of silicon implant rupture. Ann Plast Surg 1994; 33: 247-257. 4. Everson LI, Parantainen H, Detlie T, et al. Diagnosis of breast implant rupture: imaging find- ings and relative efficacies of imaging techniques. Am J Roentgenol 1994; 163: 57 -60. 5. Brown SL, Silverman BG, Berg WA. Rupture of sil- icone gel breast implants: causes, sequelae, and diagnosis. Lancet 1997; 350: 1531 -1537. 6. Mathes SJ. Breast implantation - the quest for quality and safety. N Engl J Med 1997; 336: 718- 719. 7. Brown SL, Middleton MS, Berg WA, Soo MS, Pennello G. Prevalence of rupture of silicone gel breast implants revealed on MR imaging in a pop- ulation of women in Birmingham, Alabama Am J Roentgenol 2000; 175: 1057-1064. 8. Soo MS, Kornguth PJ, Walsh R, et al. Intracapsular implant rupture: MR findings of incomplete shell collapse. J Magn Reson Imaging 1997; 4: 724 -730. 8 SA JOURNAL OF RADIOLOGY • October 2005 Fig.1 T1-weighted transverse scan of a patient with implanted prostheses demonstrating early rupture of the right prosthesis with a rupture of the posterior wall of the right prosthesis ('wavy' line or 'linguine' sign) (arrow), with fluid escaping posteriorly between the elastomer shell and the breast capsule (arrowhead). Fig. 2.T2 sagittal scan demonstrates rupture of the elastomer shell superiorly (arrow) with escape of pros- thesis contents between the elastomer shell and capsule (arrowhead). Fig.3. T2 inversion recovery magnitude or TIRM scan of a patient with a ruptured left breast prosthesis in the transverse plane. Note the prosthesis fluid collecting anterior to the breast capsule (arrows) with a rupture anteriorly of the elastomer shell. REVIEW ARTICLE pg7-8 TIB 10/8/05 10:46 AM Page 8