Benjamin Wildman-Tobriner

Thrombospondins 1 and 2 are necessary for synaptic plasticity and functional recovery after stroke.

Thrombospondins 1 and 2 (TSP-1/2) belong to a family of extracellular glycoproteins with angiostatic and synaptogenic properties. Although TSP-1/2 have been postulated to drive the resolution of postischemic angiogenesis, their role in synaptic and functional recovery is unknown. We investigated whether TSP-1/2 are necessary for synaptic and motor recovery after stroke. Focal ischemia was induced in 8- to 12-week-old wild-type (WT) and TSP-1/2 knockout (KO) mice by unilateral occlusion of the distal middle cerebral artery and the common carotid artery (CCA). Thrombospondins 1 and 2 increased after stroke, with both TSP-1 and TSP-2 colocalizing mostly to astrocytes. Wild-type and TSP-1/2 KO mice were compared in angiogenesis, synaptic density, axonal sprouting, infarct size, and functional recovery at different time points after stroke. Using the tongue protrusion test of motor function, we observed that TSP-1/2 KO mice exhibited significant deficit in their ability to recover function (P < 0.05) compared with WT mice. No differences were found in infarct size and blood vessel density between the two groups after stroke. However, TSP-1/2 KO mice exhibited significant synaptic density and axonal sprouting deficits. Deficiency of TSP-1/2 leads to impaired recovery after stroke mainly due to the role of these proteins in synapse formation and axonal outgrowth.

Using the American College of Radiology Dose Index Registry to Evaluate Practice Patterns and Radiation Dose Estimates of Pediatric Body CT

OBJECTIVE Imaging registries afford opportunities to study large, heterogeneous populations. The purpose of this study was to examine the American College of Radiology CT Dose Index Registry (DIR) for dose-related demographics and metrics of common pediatric body CT examinations. MATERIALS AND METHODS Single-phase CT examinations of the abdomen and pelvis and chest submitted to the DIR over a 5-year period (July 2011-June 2016) were evaluated (head CT frequency was also collected). CT examinations were stratified into five age groups, and examination frequency was determined across age and sex. Standard dose indexes (volume CT dose index, dose-length product, and size-specific dose estimate) were categorized by body part and age. Contributions to the DIR were also categorized by region and practice type. RESULTS Over the study period 411,655 single-phase pediatric examinations of the abdomen and pelvis, chest, and head, constituting 5.7% of the total (adult and pediatric) examinations, were submitted to the DIR. Head CT was the most common examination across all age groups. The majority of all scan types were performed for patients in the second decade of life. Dose increased for all scan types as age increased; the dose for abdominopelvic CT was the highest in each age group. Even though the DIR was queried for single-phase examinations only, as many as 32.4% of studies contained multiple irradiation events. When these additional scans were included, the volume CT dose index for each scan type increased. Among the studies in the DIR, 99.8% came from institutions within the United States. Community practices and those that specialize in pediatrics were nearly equally represented. CONCLUSION The DIR provides valuable information about practice patterns and dose trends for pediatric CT and may assist in establishing diagnostic reference levels in the pediatric population.

Common Resident Errors When Interpreting Computed Tomography of the Abdomen and Pelvis: A Review of Types, Pitfalls, and Strategies for Improvement

OBJECTIVE The purpose of this study was to identify common errors that radiology residents make when interpreting abdominopelvic (AP) computed tomography (CT) while on call, to review the typical imaging findings of these cases, and to discuss strategies for improvement. MATERIALS AND METHODS AP (or chest, abdomen, pelvis) CTs from 518 weekend senior call shifts (R3 or R4) were retrospectively reviewed. Discrepancies between preliminary and final reports were identified and then rated by whether the miss could impact short-term management. The imaging findings from the cases were reviewed. RESULTS A total of 4695 CTs were reviewed, revealing a total of 145 discrepancies that could affect short-term clinical management (miss rate 3.1%). The most common misses were related to blood clots (13.8%), colitis (8.3%), misplaced lines or tubes (6.9%), or pyelonephritis (5.5%). Common pitfalls and strategies from improved detection are discussed using image examples. CONCLUSIONS Through increased attention to the vasculature, colon, devices, and kidneys, trainees may improve their discrepancy rates and improve on-call reporting.

Mean What You Say and Say What You Mean

The “Speaking of Language” column has previously explored the importance of eliminating doubt and redundancy when assessing for change between two examinations [1]. Although the impression “No new metastases”may be commended for its brevity and lack of phrases such as “no significant change” or “no CT evidence of,” its wording still leads to uncertainty. Radiologists might use this type of phrasing when multiple prior examinations have been unchanged over many years. However, without acknowledgment of prior findings, the statement is incomplete as an impression. The referrer is left wondering about unmentioned “old” metastases. A patient reading the report via the institution’s patient portal may fear that her previously noted metastases were not fully evaluated. For

Hepatic Heterogeneity and Attenuation on Contrast-Enhanced CT in Patients With the Hypovolemic Shock Complex: Objective Classification Using a Contemporary Cohort

OBJECTIVE When objectively measured on computed tomography (CT), does hepatic heterogeneity or overall liver attenuation predict the presence of shock? METHODS This retrospective study included 73 patients (mean age 33 years) with the hypoperfusion shock complex (HSC) on CT (cases) and 100 patients (mean age 43 years) with negative trauma CT scans (controls). Liver heterogeneity was calculated by using consistently sized regions of interest (ROIs) to measure the 2 highest and the 2 lowest areas of hepatic density (in Hounsfield units [HU]). The difference between the means of the 2 highest and 2 lowest ROIs was considered the heterogeneity. Attenuation was calculated using the mean of 3 randomly placed ROIs. Both heterogeneity and attenuation were then compared between cases and controls. RESULTS Median hepatic heterogeneity was 16.8 HU (IQR: 10.7-23.4) for the HSC group and 9.0 HU (IQR: 7.0-10.4) for the controls (P < 0.001). The area under the curve was 0.79, and a threshold of 30 HU yielded a specificity of 100%. Median hepatic attenuation was not significantly different between the HSC and the control groups, with an area under the curve of 0.56. CONCLUSIONS Increased hepatic heterogeneity may represent an objective marker of the HSC that performs in a similar manner to other established signs. By comparison, overall hepatic hypoattenuation is a poor indicator of the HSC.

Pediatric providers and radiology examinations: knowledge and comfort levels regarding ionizing radiation and potential complications of imaging

BackgroundPediatric providers should understand the basic risks of the diagnostic imaging tests they order and comfortably discuss those risks with parents. Appreciating providers’ level of understanding is important to guide discussions and enhance relationships between radiologists and pediatric referrers.ObjectiveTo assess pediatric provider knowledge of diagnostic imaging modalities that use ionizing radiation and to understand provider concerns about risks of imaging.Materials and methodsA 6-question survey was sent via email to 390 pediatric providers (faculty, trainees and midlevel providers) from a single academic institution. A knowledge-based question asked providers to identify which radiology modalities use ionizing radiation. Subjective questions asked providers about discussions with parents, consultations with radiologists, and complications of imaging studies.ResultsOne hundred sixty-nine pediatric providers (43.3% response rate) completed the survey. Greater than 90% of responding providers correctly identified computed tomography (CT), fluoroscopy and radiography as modalities that use ionizing radiation, and ultrasound and magnetic resonance imaging (MRI) as modalities that do not. Fewer (66.9% correct, P<0.001) knew that nuclear medicine utilizes ionizing radiation. A majority of providers (82.2%) believed that discussions with radiologists regarding ionizing radiation were helpful, but 39.6% said they rarely had time to do so. Providers were more concerned with complications of sedation and cost than they were with radiation-induced cancer, renal failure or anaphylaxis.ConclusionProviders at our academic referral center have a high level of basic knowledge regarding modalities that use ionizing radiation, but they are less aware of ionizing radiation use in nuclear medicine studies. They find discussions with radiologists helpful and are concerned about complications of sedation and cost.

Design, implementation, and demographic differences of HEAL: a self-report health care leadership instrument

The medical community has recognized the importance of leadership skills among its members. While numerous leadership assessment tools exist at present, few are specifically tailored to the unique health care environment. The study team designed a 24-item survey (Healthcare Evaluation & Assessment of Leadership [HEAL]) to measure leadership competency based on the core competencies and core principles of the Duke Healthcare Leadership Model. A novel digital platform was created for use on handheld devices to facilitate its distribution and completion. This pilot phase involved 126 health care professionals self-assessing their leadership abilities. The study aimed to determine both the content validity of the survey and the feasibility of its implementation and use. The digital platform for survey implementation was easy to complete, and there were no technical problems with survey use or data collection. With regard to reliability, initial survey results revealed that each core leadership tenet met or exceeded the reliability cutoff of 0.7. In self-assessment of leadership, women scored themselves higher than men in questions related to patient centeredness (P=0.016). When stratified by age, younger providers rated themselves lower with regard to emotional intelligence and integrity. There were no differences in self-assessment when stratified by medical specialty. While only a pilot study, initial data suggest that HEAL is a reliable and easy-to-administer survey for health care leadership assessment. Differences in responses by sex and age with respect to patient centeredness, integrity, and emotional intelligence raise questions about how providers view themselves amid complex medical teams. As the survey is refined and further administered, HEAL will be used not only as a self-assessment tool but also in “360” evaluation formats.