Faculty Bibliography

The diagnosis and treatment of breast cancer are dependent upon early detection of the disease by physical examination and mammography. Although mammography is a relatively good and cost-effective method of early breast cancer detection, there are some inherent weaknesses associated with this imaging modality that limit its sensitivity and specificity. Contrast-enhanced MRI of the breasts provides the additional capability to answer questions raised or unanswered with conventional imaging methods. This paper reviews contrast-enhanced breast MRI interpretation guidelines and patient preselection criteria for diagnostic problem cases. Technical aspects using a commercially available three-dimensional (3D) spoiled gradient-echo technique are discussed.

Magnetic resonance (MR) angiography has been shown to be an important technique to image the vasculature of the lower extremities. The two-dimensional (2D) time-of-flight technique has evolved as the standard method of MR angiography used to examine patients with peripheral arterial occlusive disease (PAOD). There is evidence that cardiac triggering substantially improves the quality of 2D time-of-flight angiography. In this pictorial essay, we describe PAOD, show the results of this nonintrusive angiographic technique, and provide a current overview of the interventional and surgical management of PAOD.

Occasionally, artifacts may simulate pathologic conditions on magnetic resonance (MR) images. Motion artifacts especially affect images of the chest and abdomen. There are a number of techniques for reducing motion artifacts, including respiratory and cardiac gating, k-space phase reordering, gradient moment nulling, even echo rephasing, and physical restraints. Aliasing occurs when the field of view does not include all of the anatomic structures present in the imaged section. Aliasing artifacts can be eliminated by increasing the field of view, oversampling, and use of saturation pulses or surface coils. Truncation artifacts represent the difference between the original and the reconstructed image and can be reduced with data extrapolation algorithms or image filtering. Chemical shift artifacts and magnetic susceptibility artifacts are due to a local deformity of the magnetic field, resulting in spatial misregistration. Chemical shift artifacts are more severe in images acquired with a narrow-bandwidth technique; magnetic susceptibility artifacts are more severe in images acquired with a long echo time. Pitfalls in the interpretation of MR images can be avoided by becoming familiar with the appearances and causes of common MR imaging artifacts.

Two patients with pseudocoarctation complicated by dissection are presented. They are the first cases in which pseudocoarctation with dissection have been imaged by magnetic resonance (MR). MR imaging is an excellent noninvasive modality in the evaluation of dissection in pseudocoarctation of the aorta.