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Ultrasonic Mammographic Parenchymal Patterns: A Preliminary Report 1 Carl S. Rubin, D.O., Alfred B. Kurtz, M.D., Barry B. Goldberg, M.D., Stephen Feig, M.D., and Catherine ColeBeuglet, M.D. Ultrasound has been suggested as a lower risk alternative to mammography for detecting breast abnormalities. Mammograms and ultrasonograms of 32 women patients were compared, revealing three distinct ultrasonic parenchymal patterns which corresponded to previously reported mammographic patterns: fatty (N 1), ductal (P1 or P2), and dysplastic (DY). These constitute a new system of parenchymal classification, to our knowledge. INDEX TERMS: Breast, ultrasound, 0 [0] .1298 • Breast neoplasms, ultrasound diagnosis • Mammography

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The problem of identifying patients who are at high risk for the development of breast cancer remains a challenge to all physicians. Various techniques have been used, including manual examination, thermography, and x-ray mammography. Wolfe has proposed a correlation between x-ray mammographic parenchymal patterns and risk (6, 7). However, there is currently controversy concerning the relative risks and benefits of mammography (4). Ultrasonic scanning has been suggested as an alternative. Usingthis method, we were able to identify distinct parenchymal patterns that corresponded to Wolfe's x-ray criteria.

Fig. 1. N1 or fatty pattern. A. Cranial caudal xeroradiograph showing a fatty breast (F). Some stromal fibrosis is seen in the outer quadrants (FS) (arrowheads). B. Transverse ultrasonogram showing circumscribed areas of decreased echogenicity (F) representing fat. The high-amplitude, coalescent area in the outer quadrant (arrowheads) corresponds to the area of stromal fibrosis on the xerograph.

MATERIALS AND METHOD One hundredbreasts in 50 women ranging from 25 to 70 years of age were scanned ultrasonically using a multitransducer Bscanner with automated water delay (UI Octoson-Ausonics) (3). The patients lay prone with their breasts freely suspended in the water bath. Images were obtained using all eight 3-mHz transducers, a combination of two or more, or a single transducer, which are mechanically sectored in 60° arcs. The simultaneous use of two or more transducers produces a compound image, whereas a single transducer gives a sector scan. The sector images which record information from a single line of sight give a truer representation of the structural organization of the tissue (2). For this reason, single-transducer scans were used exclusively in compiling the parenchymal classification. The breast was imaged in its sagittal and transverse projections. The former corresponds to the medial lateral mammogram, the latter to the cranial caudal view. Scans were obtained at intervals of 2 mm. A permanent record was made on Polaroid or x-ray film, using a multiformat imager. Mammograms or xerograms were obtained for 32 patients within a month of the examination. Using Wolfe's criteria, a comparison of the ultrasonograms to the mammograms was made by two of us (C.R. and S.F.). Three of us (A.K., B.B.G., C.C.B) were shown the ultrasonograms without knowledge of the mammographic results and requested to classify the dominant ultrasonic pattern. Classifications were based on (a) the arrangement of the echoes, referred to as the textural pattern (discreteness or coalescence; distribution) and (b) analysis of size (coarseness or fineness) and brightness of individual echoes. Each breast served

as its own standard, with relative echogenicity determined by comparison to the skin. RESULTS In all cases, the authors' classifications corresponded to the mammographic patterns. Variations were seen only when the component tissues, namely skin, collagen, and fat, varied from the dominant pattern. This is not surprising, since the ultrasonogram is a tomographic slice of tissue, while the mammogram represents a superimposition of densities. The echo amplitude of the component tissues varied in magnitude. Collagen gave rise to very strong echoes, while fat reduced echogenicity (1). The skin was the most echogenic structure and displayed maximum brightness. Areas of collagen closely approximated the skin in brightness. Fatty areas were very weakly echogenic. Three ultrasonic patterns of parenchymal echoes were established: (a) Fatty (N 1) (14 patients): Discrete, circumscribed, weakly echogenic foci with strongly echogenic borders were observed. There was no enhanced sound transmission distal to the foci (Fig. 1).

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Fig. 2. Ductal pattern. A. Cranial caudal xeroradiograph showing a ductal pattern (P2)' There is a small area of stromal fibrosis (FS) (arrowheads). M = medial. B. Transverse ultrasonogram shows multiple punctate, noncoalescent echoes (P2) within the central portion of the breast. This represents the ultrasonic ductal pattern with discrete echoes. The stromal fibrosis (FS) seen medially (M) is greater in amplitude than the ductal echoes, and shows coalescence (arrowheads). Similar coalescent, high-amplitude fibrosis is seen laterally.

(b) Ductal (P1) (2 patients) or (P2) (5 patients): Discrete dots or thin lines without coalescence were seen. The echo amplitude was less than in the skin, the dysplastic pattern, or areas of stromal fibrosis (Fig. 2). Sometimes the lines were seen as thin, vertical bands radiating to the nipple (Fig. 3), especially in the P2 pattern. No other ultrasonic feature differentiated P 1 from P2·

(c) Dysplastic (DY) (11 patients): Echoes were linear or clumped together and coalescent. The thick, high amplitude approximated the brightness of the skin (Fig. 4). The echoes did not radiate to the nipple.

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Fig. 3. Ductal pattern. A. Medial-lateralxeroradiographshowing a ductal pattern (0) within the lower half of the breast (broken lines). Stromal fibrosis (FS) is present within the upper portion (arrowheads). CL = Cooper ligaments; F = subcutaneous fat; H = direction of head. B. Sagittal ultrasonogram showing linear echoes (0) radiating to the nipple within the lower half of the breast. The coalescent, highamplitude echo complex (arrowheads) shows stromal fibrosis (FS). F = subcutaneous fat; CL = Cooper ligaments.

represents severe dysplasia with varying degrees of desmoplasia (6). It is our hypothesis that, due to a smaller amount of collagen, the echoes in the former are lower and more discrete than those in the latter. The distribution of the collagen in the ductal region may be responsible for the radiation of the echoes toward the nipple. The coalescence seen in the DY pattern may reflect both diffuseness and greater degrees of dysplasia and collagenosis.

DISCUSSION In the past, ultrasound has been used mainly as a complement to x-ray mammography in the diagnosis of palpable breast abnormalities (5). It has proved less useful in defining parenchymal patterns, due chiefly to technical limitations such as inadequate resolution, and breast compression with resultant anatomical distortion. However, these problems have been largely overcome by the use of the high-resolution, mechanically sectored water-path scanner. As our findings show, ultrasound can be used to identify the tissues within the breast and their structures. The differentiation in patterns and their magnitudes constitute a new system of classification. The chief histological feature of the ductal pattern (P 1 or P2 ) is periductal collagenosis, while the dysplastic pattern (DY)

CONCLUSION The ultrasonic equivalents of Wolfe's x-ray mammographic parenchymal patterns have been identified and presented. This work forms the basis of future investigation into the sensitivity and specificity of the various ultrasonic mammographic patterns.

REFERENCES 1. Jellins J, Kossoff G, Reeve TS, et al: Ultrasonic grey scale visualization of breast disease. Ultrasound Med BioI 1; 393-404, Mar 1975

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2. Kossoff G, Garrett WJ, Carpenter DA, et al: Principles and classification of soft tissues by grey scale echography. UltrasoundMed Bioi 2: 89-105, Feb 1976 3. Kossoff G, Carpenter DA, Robinson DE, et al: Octoson-a new rapid general purpose echoscoppe. [In]White D, Barnes R, ed: Ultrasound in Medicine. New York, Plenum Press, 1976, Vol 2, pp 333339 4. Lester R: Risk versus benefit in mammography. Radiology 124:16, Jul 1977 5. Teixidor HS, Kazam E: Combined mammographic-sonographic evaluation of breast masses. Am J Roentgenol 128:409-417, Mar 1977 6. Wolfe IN: Breast patterns as an index of risk for developing breast cancer. Am J RoentgenoI126:1130-1137, Jun 1976 7. Wolfe IN: Risk for breast cancer development determined by mammographic parenchymal pattern. Cancer 37:2486-2492, May 1976

1 From the Division of Diagnostic Ultrasound, Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, Penn. Received July 20, 1978; accepted and revision requested Aug. 28; revision received Sept. 26. as

Fig. 4. Dysplastic pattern or DY. A. Cranial caudal xeroradiograph showing a uniformly dense breast consistent with a DY pattern. M= medial. B. Transverse ultrasonogram showing diffuse coalescent echoes of medium and high amplitude. The echoes are not discrete and do not radiate to the nipple.

Ultrasonic mammographic parenchymal patterns: a preliminary report.

Work In Progress WORK IN PROGRESS Vol. 130 Ultrasonic Mammographic Parenchymal Patterns: A Preliminary Report 1 Carl S. Rubin, D.O., Alfred B. Kurt...
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