Faculty Bibliography

The increasing incidence of pediatric dysphagia has raised questions about how to identify children at risk for aspiration. Multiple investigative imaging modalities are considered in diagnostic algorithms, since dysphagia may involve any or all phases of swallowing. Although upper gastrointestinal (UGI) series and videofluoroscopic swallow study (VFSS) are common procedures, the utility of UGI for detection of aspiration and the impact of oropharyngeal imaging during UGI on radiation exposure have not been well described. We hypothesized that diagnosis of aspiration on UGI would be predictive of aspiration on VFSS and screening swallows during UGI would increase radiation exposure. A retrospective review was completed of bottle-fed children undergoing UGI series within 1 month before/after standardized VFSS. UGI was imaged at 3 frames per second (fps) pulsed and VFSS at 30 fps continuous fluoroscopy. Cumulative radiation dose (CD) and dose area product (DAP) were recorded. VFSS and UGI were performed in 49 patients; however, only 21 (43 %) had documentation of swallow function on an UGI series. All children with aspiration on UGI demonstrated thin liquid aspiration on VFSS; however, 53 % without aspiration on UGI aspirated on VFSS. CD for UGI with versus without swallowing documentation was significantly higher (median = 0.33 vs. 0.21 mGy, p = 0.02) but within variability ranges reported for fluoroscopy equipment. DAP was not significantly higher for UGI with documentation of swallowing compared to without documentation of swallowing (median = 4.11 vs. 3.02 muGy cm(2), p = 0.09). UGI findings are specific but not sensitive markers for aspiration on VFSS. Imaging of swallowing on UGI may have an appreciable increase on radiation exposure.

This pictorial review demonstrates imaging features of extramammary malignancies metastatic to the breast seen with multiple modalities, including mammography, ultrasound, computed tomography (CT), positron emission tomography, and magnetic resonance imaging. Although rare, metastases to the breast may have a distinct imaging appearance from the appearance of primary breast cancers. They are important to identify because they can mimic benign breast disease and their treatment differs from that of primary breast cancer. Metastatic disease to the breast most commonly appears as a single round or oval mass with circumscribed margins. Sonographically it is usually hypoechoic, and with CT or magnetic resonance imaging it usually enhances. In contrast with primary breast cancer, breast metastases do not demonstrate spiculated margins and rarely have associated calcifications. A variety of clinical presentations of breast metastases are reviewed, including presentation with a palpable mass, detection at screening mammography, and detection with CT or positron emission tomography.

The cerebellum is involved in the update of motor commands during error-dependent learning. Transcranial direct current stimulation (tDCS), a form of noninvasive brain stimulation, has been shown to increase cerebellar excitability and improve learning in motor adaptation tasks. Although cerebellar involvement has been clearly demonstrated in adaptation paradigms, a type of task that heavily relies on error-dependent motor learning mechanisms, its role during motor skill learning, a behavior that likely involves error-dependent as well as reinforcement and strategic mechanisms, is not completely understood. Here, in humans, we delivered cerebellar tDCS to modulate its activity during novel motor skill training over the course of 3 d and assessed gains during training (on-line effects), between days (off-line effects), and overall improvement. We found that excitatory anodal tDCS applied over the cerebellum increased skill learning relative to sham and cathodal tDCS specifically by increasing on-line rather than off-line learning. Moreover, the larger skill improvement in the anodal group was predominantly mediated by reductions in error rate rather than changes in movement time. These results have important implications for using cerebellar tDCS as an intervention to speed up motor skill acquisition and to improve motor skill accuracy, as well as to further our understanding of cerebellar function.