Exhibit Update

The following exhibit has been withdrawn:
E240: Musculoskeletal.
Author: Hythem Omar.
Title: The role of magnetic resonance imaging in the diagnosis of chronic exertional compartment syndrome.

The following exhibit replaces :
E272: Breast: MRI.
Author: A. Mehdizade.
Title: MRI of the Breast Post Biopsy

NEW E272: Breast: MRI.
Can Breast MRI Be Useful In Determining Histologic Grade of Breast Carcinomas? Mercado C.L.¹; Moy L.¹; Toth H.K.¹; Cangiarella J¹
1. NYU Medical Center Radiology New York, NY.
Address correspondence to L. Moy.
Objective: Studies have shown an association between histologic grade and survival from breast carcinoma. We evaluated the ability of breast MRI to distinguish different histologic grades of infiltrating ductal carcinoma and thus serve as a predictor of prognosis.
Materials and Methods: We retrospectively identified 28 mammary IDCs that were imaged with contrast enhanced MRI. Patient mean age was 43 years (range, 30-66). All breast MRI images were reviewed. The lesion size, morphologic and kinetic characteristics according to the ACR lexicon were recorded. Pathologic findings were reviewed and graded according to the Modified Bloom Richardson grading scheme.
Results: Pathologic analysis showed 15 poorly differentiated, 8 moderately differentiated, and 5 well differentiated IDCs. Mean lesion size was 2.6 cm(range, 0.9-3.9 cm) for the poorly differentiated, 2.0 cm(range, 1.5-3.8 cm) for the moderately differentiated, and 1.5 cm(range, 1.0-1.9 cm) for the well differentiated. Twenty(71%) presented as a mass only. Eight(29%) presented as a mass with adjacent peripheral enhancement. Poorly differentiated IDCs showed irregular shape in 11(73%), irregular margins in 11(73%), rim enhancement in 10(67%) and heterogeneous enhancement in 4(27%). Moderately differentiated IDCs showed irregular shape in 5(63%), irregular margins in 4(50%) and spiculate margins in 4(50%). Enhancement was heterogeneous in 4(50%), rim enhancing in 2(25%) and homogeneous in 2(25%). Well differentiated IDCs were all irregular in shape with spiculate margins in 4 or irregular margins in 1. Enhancement was heterogeneous in 2, rim enhancing in 2 and homogeneous in 1. Enhanced internal septations were seen in 7(47%) of the poorly differentiated, and in 1(13%) of the moderately differentiated lesions. Central enhancement was seen in 3(20%), of which all were poorly differentiated. The majority(23 lesions) were not hyperintense on the T2 weighted images. Of the 5 lesions with increased T2 signal, 2 were poorly, 2 moderately and 1 well differentiated. All lesions had initial rapid enhancement with either plateau or washout delayed phase.
Conclusion: While MRI features such as enhancing internal septations and central enhancement can suggest a poorly differentiated IDC, few demonstrate these findings. MRI morphologic features such as irregular shape or margins, and rim or heterogeneous enhancement may be frequently seen in poorly differentiated IDC, but are not specific. The ability of breast MRI to distinguish between different grades of IDCs is poor.