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Mammographic and CT Findings After Breast Reconstruction with a Rectus Abdominis Musculocutaneous Flap Evelyne

M. Loyer,1


S. Kroll,2


L. David,1


This essay illustrates the radiologic appearance of the reconbreast and the abdominal wall after breast reconstruction with a transverse rectus abdominis musculocutaneous (TRAM) flap. The findings are based on a retrospective study of 42 mammograms, 17 abdominal CT scans, and two CT scans each of the chest and pelvis of patients who underwent this

A. DuBrow,1




I. Libshitz1



procedure. Breast reconstruction is an important part of the treatment of mastectomy patients and is performed with increasing frequency. Various methods of reconstruction are available, all of which are intended to create a natural-appearing breast. Some require the use of implants; others are based on the use of musculocutaneous flaps. The transverse rectus abdominis musculocutaneous (TRAM) flap technique is a modified abdominoplasty in which abdominal skin and fat are transferred to the chest and used to reconstruct the absent breast. It is currently the most frequent method of reconstruction at many institutions [1 2]. Mammography of the reconstructed breast is performed to detect local tumor recurrence in the chest wall. CT of the abdomen is also frequently performed in these patients as part of their follow-up for metastatic disease. ,

Received August 30, 1 990; accepted after revision December 1 0, 1990. 1 Department of Diagnostic Radiology, The University of Texas M.D. Anderson requests to HI. Libshitz. 2 Department of General Houston,



of Plastic

and Reconstructive


The TRAM flap method of breast reconstruction (Fig. 1) uses an ellipse of lower abdominal fat and skin and one or both rectus abdominis muscles. One or both muscle pedicles may be used. The blood supply depends on perforating vessels from the underlying rectus abdominis muscles. The vascular supply is preserved by leaving intact the superior epigastric vessels. The umbilicus is left behind in the abdomen, usually creating a small round defect in the skin of the flap. The flap is rotated around its attachment just below the junction of the xiphoid process and the costal margin. If a single muscle pedicle is used, it most often is taken from the side opposite that of the reconstructed breast. A subcutaneous tunnel is dissected between the abdomen and the site of the reconstructed breast, and the flap, along with its muscular pedicle, is passed through the tunnel. Although the flap itself becomes located entirely at the new breast site, part of the muscle pedicle (or pedicles) remains permanently in the tunnel. At the site of the previous mastectomy, an incision is made in the skin and subcutaneous fat in such a way that it is



The University

TX 77030.

AJR 156:1159-1162,


1991 036i-803X/91/i


© American


Ray Society

1 51 5 Holcombe of Texas


M.D. Anderson

Houston, Cancer

TX 77030. Center,


1515 Hoboombe

reprint Blvd.,



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Fig. 1.-Surgical procedure: single muscle pedicle. A, Diagram shows location of donor site and intermediate position of flap. B, Diagram shows location of musculocutaneous flap to form new breast.


Fig. 2.-A, Normal left breast, mediolateral mammogram. B and C, Reconstructed right breast, medbolateral (B) and craniocaudal (C) mammograms. Absence of ductal pattern is seen when cornpared with normal side. Elevated rectus muscle is seen along chest wall (arrows).


Fig. 3.-A



and B, Diagrams



as seen

on medial

and contact

lateral views (A) and on craniocaudal view (B). Line A corresponds to superior edge of flap. (Dotted line shows variable position of scar.) Lines G and H were rarely seen and correspond to lateral and medial edges of flap. Line B was inconsistently related to lateral edge of flap. Line C results from closure of defect created in flap by dissection of umbilicus.


June 1991




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symmetric with the contralateral inframammary fold. The flap is then inserted in the defect created by this incision and sculpted into a facsimile of the absent breast. The abdominal wall defects are closed primarily.







On mammography, tively homogeneous,

the reconstructed predominantly fatty

Fig. 4.-A-C, Mediolateral (A), contact lateral (B), and craniocaudal (C) mammograms of reconstructed left breast show superior edge of flap scar A (arrowheads), lateral edge of flap scar B (open arrows), and closure of umbilical defect scar C (short solid arrows). Elevated recftls muscle is evident (thin solid arrows).

Fig. 5.-A-C, Mediolateral (A), contact lateral (B), and craniocaudal (C) mammograms of reconstructed right breast show superior edge of flap only (scar A, arrowheads) and elevated recftjs muscle (arrows). A



breast has a relaappearance (Fig. 2),

Fig. 6.-Reconstruction of right breast by using a single muscle pedicle from left side. A, CT scan shows left rectus muscle (arrows)

in upper abdominal wall. B, CT scan shows left rectus abdominus mus(arrows) along chest wall deep in reconstructed breast. Note absence of periglandular connective tissue in reconstructed breast.

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Fig. 7.-CT

scan of reconstructed

right breast

shows triangular opacity in mid and upper breast, most likely related to rectus abdominis muscle. Medial and lateral scars (arrowheads) are noted also.

Fig. 8.-CT scan of abdomen obtained after reconstruction of breast by using single right muscle pedicle. Right rectus abdominis muscle

is no longer seen. Fascia transversalis tutes anterior abdominal wall.

which can be similar to the pattern seen in postmenopausal women. This pattern however, is less organized and more amorphous, with fewer vascular and connective tissue opacities and without ductal structures or supporting ligaments. On the mediolateral and contact lateral views, the elevated rectus muscle(s) is seen as a vertically oriented opacity antenor to the pectoralis major muscle (Figs. 2B and 2C). Because of its deep position in the breast, it is less frequently seen on the craniocaudal view. The volume of the muscle varies from an obvious, well-defined bulky mass to faint, almost imperceptible strands of tissue. Scars are visible in all reconstructed breasts. They are either related to the reconstruction technique itself (suture of the flap, closure of the umbilical defect) or were present before the reconstruction (mastectomy scar, abdominal scar included in the flap). Although variation in the appearance of the scars is considerable, some common patterns can be defined (Figs. 3-5). The scar that unites the flap to the skin of the chest wall has a somewhat ovoid pattern. Line A (Figs. 3-5) corresponds to the superior edge of the flap, which is usually seen on the contact and mediolateral views. It is seen on the craniocaudal view only if located low enough on the breast. Line D (Fig. 3) represents the inferior edge of the flap, which can be seen on contact and mediolateral views. Line C (Figs. 3 and 4) corresponds to the scar created in the skin portion of the flap by the dissection around the umbilicus. Line B (Figs. 3 and 4) is inconsistently seen and correlates either with the lateral edge


of the flap, the original mastectomy scar, or a prominent skin fold. Lines G and H on the craniocaudal view were rarely seen and also correspond to the lateral edges of the flap. On CT, the reconstructed breasts have a homogeneous fatty density. The elevated rectus abdominis muscle(s) can be followed from approximately the level of the epigastrium up into the mound of the new breast. It is seen against the chest wall with a horizontal to oblique orientation (Fig. 6). Scars are observed medially and laterally extending from the skin posteriorly to the chest wall (Fig. 7). The findings due to the reconstruction are superimposed on the postmastectomy changes. The anatomy of the residual pectoralis muscle is highly variable and sometimes suggests local recurrence [3, 4]. On abdominal CT, an abdominal wall defect is seen clearly in all patients, involving one or both rectus muscles. The level of rotation of the pedicle is in the epigastrium, where muscle tissue can be seen crossing the midline (Fig. 8). REFERENCES 1 . Kroll 55. Cancer concepts in breast reconstruction after mastectomy. Tex Med 1989:85:40-46 2. Hartrampf CR, Scheflan M, Black PW. Breast reconstruction with a transverse abdominal island flap. Plast Reconstr Surg 1982:69(2):216-225 3. Shea WJ, deGeer G, Webb WA. Chest wall after mastectomy: 1 . CT appearance of normal postoperative anatomy, postirradiation changes, and optimal scanning techniques. Radiology 1987;162: 157-i6i 4. Shea WJ, deGeer G, Webb WA. Chest wall after mastectomy: 2. CT appearance of tumor recurrence. Radiology 1987:162:162-164

Mammographic and CT findings after breast reconstruction with a rectus abdominis musculocutaneous flap.

This essay illustrates the radiologic appearance of the reconstructed breast and the abdominal wall after breast reconstruction with a transverse rect...
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