Sir: Quantitative breast volume assessment may optimize the results in breast surgery. Methods such as the anthropomorphic method, using thermoplastic sheets, counting displaced water, and three-dimensional photography have been described.1 We thought that magnetic resonance tomography, which is an accepted diagnostic and volumetric tool for the female breast, might serve also as a breast volumetry measure.2,3 Calculating volumes of specific organs or tissues is possible because of the different densities of various tissues.4 Current image-guided neuronavigation in neurosurgical procedures provides helpful surgical guidance for planning and performing the procedure by referencing the coordinate system of the brain to a parallel coordinate system based on three-dimensional image data of the patient on the console of the computer workstation. The medical images become point-to-point maps of the corresponding actual locations of the brain.5 Current neurosurgical systems include a tool with which to calculate the volume of the previously marked lesion. We hypothesized that magnetic resonance imaging data sets of the breast could be processed like cranial magnetic resonance imaging data for magnetic resonance imaging–based breast volumetry. In a pilot approach, we studied a 42-year-old woman who had undergone bilateral breast augmentation with 270-cc silicone implants on both sides 8 years previously. Magnetic resonance imaging examinations had been performed with a 1.5-T magnetic resonance scanner (MRT Gyroscan Intera 1.5 T; Philips, Hamburg, Germany) with the patient in the prone position. The implant was intact on the magnetic resonance imaging scans. Given the known size of the intact implant from the implant pass, another blinded examiner performed the volume analysis of the breast using Brainlab I Plan 2.6 navigation software. The process of marking the borders of the breast implant within the patient's breast is simple and straightforward (<2 minutes) (Fig. 1). The amount of the overlying breast tissue is easily measured and calculated by the software as well (Fig. 2). The magnetic resonance imaging–based volumetry of the implants was 273 cc for the right side and 275 cc for the left side, with 270-cc built-in implants based on the implant pass. Thus, the magnetic resonance imaging breast volumetry was within a 2 percent error of the size of the original breast implant. Also, the volume of the total breast with the implant could be calculated in the same setting, which was 570 cc on the right side and 559 cc on the left side.Fig. 1.: Using Brainlab I Plan 2.6 navigation software, the mammary implants are marked on axial slices by surrounding them with a digital pen guided by the computer mouse. This process can be performed simply and quickly. An included volume analysis tool calculates the volume of the marked tissue, like the left-sided breast implant in this screen shot. The calculated volume was 275 cc, with 270 cc given in the implant pass.Fig. 2.: The entire female breast can be visualized and the volume can be analyzed. Because axial, sagittal, and coronal slices can be processed, a naturalistic image of the breast is available. Analyzed breast volumes were 570 cc on the right side and 559 cc on the left side.The advantage of magnetic resonance imaging–based breast volumetry is the fact that often magnetic resonance imaging data are available to rule out implant rupture,2 to quantify capsular contracture, and for breast cancer screeninig.3 The use of magnetic resonance imaging–based volumetry is intriguing because the navigation software is often available in the hospitals were neurosurgical units are on call. We thought to transfer the current neurosurgical practice for magnetic resonance imaging–based breast volumetry. We found our pilot results encouraging, with a variation of less than 2 percent, in contrast to the real implant size in two measurements with blinded operators. However, large-scale prospective trials are warranted to elucidate the value of preoperative magnetic resonance imaging–based breast volumetry. DISCLOSURE None of the authors has any commercial associations that might pose or create a conflict of interest with information on products presented in this article. Christian Herold, M.D. Karsten Knobloch, M.D., Ph.D. Department of Plastic, Hand, and Reconstructive Surgery; Hannover Medical School Lennart H. Stieglitz, M.D. Amir Samii, M.D., Ph.D. International Neuroscience Institute Peter M. Vogt, M.D., Ph.D. Department of Plastic, Hand, and Reconstructive Surgery; Hannover Medical School; Hannover, Germany
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