Multimodality Imaging of Postmastectomy Breast Reconstruction Techniques, Complications, and Tumor Recurrence.

For women undergoing mastectomy, breast reconstruction can be performed by using implants or autologous tissue flaps. Mastectomy options include skin- and nipple-sparing techniques. Implant-based reconstruction can be performed with saline or silicone implants. Various autologous pedicled or free tissue flap reconstruction methods based on different tissue donor sites are available. The aesthetic outcomes of implant- and flap-based reconstructions can be improved with oncoplastic surgery, including autologous fat graft placement and nipple-areolar complex reconstruction. The authors provide an update on recent advances in implant reconstruction techniques and contemporary expanded options for autologous tissue flap reconstruction as it relates to imaging modalities. As breast cancer screening is not routinely performed in this clinical setting, tumor recurrence after mastectomy and reconstruction is often detected by palpation at physical examination. Most local recurrences occur within the skin and subcutaneous tissue. Diagnostic breast imaging continues to have a critical role in confirmation of disease recurrence. Knowledge of the spectrum of benign and abnormal imaging appearances in the reconstructed breast is important for postoperative evaluation of patients, including recognition of early and late postsurgical complications and breast cancer recurrence. The authors provide an overview of multimodality imaging of the postmastectomy reconstructed breast, as well as an update on screening guidelines and recommendations for this unique patient population. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Optimizing Image Quality When Evaluating Blood Flow at Doppler US: A Tutorial.

Doppler US is an essential component of nearly all diagnostic US procedures. In this era of increased awareness of the effects of ionizing radiation and the side effects of iodine- and gadolinium-based contrast agents, Doppler US is poised to play an even bigger role in medical imaging. It is safe, cost-effective, portable, and highly accurate when performed by an experienced operator. The sensitivities and specificities of Doppler US for detecting blood flow and determining the direction and velocity of blood flow in various organs and vascular systems have increased dramatically in the past decade. With use of advanced flow techniques that are available for use with most modern equipment, US can provide vascular information that is comparable to or even more accurate than that obtained with other cross-sectional and interventional modalities. However, there remains concern that US (including newer more advanced flow-evaluating techniques) will not be used to its full potential owing to dependence on operator skill and expertise. Thorough understanding of image optimization techniques and expanded knowledge of the physical principles, instrumentation, application, advantages, and limitations of this modality are of utmost importance. The authors provide a simple practical guide for optimizing images for vascular flow detection by reviewing various cases and focusing on the parameters that should be optimized. Online supplemental material is available for this article. ©RSNA, 2019 See discussion on this article by Pellerito.

Implantable Electronic Stimulation Devices from Head to Sacrum: Imaging Features and Functions.

Electronic stimulation devices are implanted in various locations in the body to decrease pain, modulate nerve function, or stimulate various end organs. The authors describe these devices using a craniocaudal approach, first describing deep brain stimulation (DBS) devices and ending with sacral nerve stimulation (SNS) devices. The radiology-relevant background information for each device and its imaging appearance are also described. These devices have a common design theme and include the following components: (a) a pulse generator that houses the battery and control electronics, (b) an insulated lead or wire that conveys signals to the last component, which is (c) an electrode that contacts the end organ and senses and/or acts on the end organ. DBS electrodes are inserted into various deep gray nuclei, most commonly to treat the symptoms of movement disorders. Occipital, trigeminal, and spinal nerve stimulation devices are used as second-line therapy to control craniofacial or back pain. For cardiac devices, the authors describe two newer devices, the subcutaneous implantable cardioverter defibrillator and the leadless pacemaker, both of which avoid complications related to having leads threaded through the venous system. Diaphragmatic stimulation devices stimulate the phrenic nerve to restore diaphragmatic movement. Gastric electrical stimulation devices act on various parts of the stomach for the treatment of gastroparesis or obesity. Finally, SNS devices are used to modulate urinary and defecatory functions. Common complications diagnosed at imaging include infection, hematoma, lead migration, and lead breakage. Understanding the components, normal function, and normal imaging appearance of each device allows the radiologist to identify complications. ©RSNA, 2019.