Kimberly E. Lind

Validation of Software Gating: A Practical Technology for Respiratory Motion Correction in PET

Purpose To assess the performance of hardware- and software-gating technologies in terms of qualitative and quantitative characteristics of respiratory motion in positron emission tomography (PET) imaging. Materials and Methods Between 2010 and 2013, 219 fluorine 18 fluorodeoxyglucose PET examinations were performed in 116 patients for assessment of pulmonary nodules. All patients provided informed consent in this institutional review board-approved study. Acquisitions were reconstructed as respiratory-gated images by using hardware-derived respiratory triggers and software-derived signal (via an automated postprocessing method). Asymmetry was evaluated in the joint distribution of reader preference, and linear mixed models were used to evaluate differences in outcomes according to gating type. Results In blind reviews of reconstructed gated images, software was selected as superior 16.9% of the time (111 of 657 image sets; 95% confidence interval [CI]: 14.0%, 19.8%), and hardware was selected as superior 6.2% of the time (41 of 657 image sets; 95% CI: 4.4%, 8.1%). Of the image sets, 76.9% (505 of 657; 95% CI: 73.6%, 80.1%) were judged as having indistinguishable motion quality. Quantitative analysis demonstrated that the two gating strategies exhibited similar performance, and the performance of both was significantly different from that of nongated images. The mean increase ± standard deviation in lesion maximum standardized uptake value was 42.2% ± 38.9 between nongated and software-gated images, and lesion full width at half maximum values decreased by 9.9% ± 9.6. Conclusion Compared with vendor-supplied respiratory-gating hardware methods, software gating performed favorably, both qualitatively and quantitatively. Fully automated gating is a feasible approach to motion correction of PET images. (©) RSNA, 2016 Online supplemental material is available for this article.

Dural sinus stenting for idiopathic intracranial hypertension: factors associated with hemodynamic failure and management with extended stenting

Background Some patients undergoing dural sinus stenting for idiopathic intracranial hypertension (IIH) develop clinical and hemodynamic failure (recurrence of the pressure gradient) owing to stent-adjacent stenosis. Objective To characterize factors associated with hemodynamic failure, and to describe outcomes of patients after repeat stenting. Materials and methods We reviewed the initial and follow-up clinical, venographic, and hemodynamic data in 39 patients with IIH treated over 17 years with stenting. Thirty-two had follow-up angiographic and hemodynamic data at 1–99 months (mean 27.6, median 19.5 months). Eight patients were treated with 12 repeat stenting procedures, including extended stenting into the superior sagittal sinus (SSS). Results All patients had an initial successful hemodynamic result with the pressure gradient reduced from 10–43 to 0–7 mm Hg. 10/32 patients (31.3%), all women, developed new stenoses in the transverse sinus or posterior SSS above the stent with a recurrent pressure gradient. 7/9 patients with pure extrinsic stenosis of the transverse-sigmoid junction pre-stenting developed new stenoses and hemodynamic failure. All patients with hemodynamic failure who were restented had early and mid-term documented hemodynamic success at 1.7–50 months. They were free from papilledema at 3.8–50 months after the last restenting, and 11.5–99.5 months after initial stent placement (mean 45.3, median 38.5 months). Conclusions Pure extrinsic compression of the transverse-sigmoid junction and female gender were strongly associated with hemodynamic failure. Eight patients with hemodynamic failure who were restented had successful control of papilledema, including 4/4 who had extended stenting into the SSS.

Sex disparities in substance abuse research: Evaluating 23 years of structural neuroimaging studies

BACKGROUND Sex differences in brain structure and clinical course of substance use disorders underscores the need to include women in structural brain imaging studies. The NIH has supported the need for research to address sex differences. We evaluated female enrollment in substance abuse structural brain imaging research and the methods used to study sex differences in substance effects. METHODS Structural brain imaging studies published through 2016 (n=230) were evaluated for number of participants by sex and substance use status and methods used to evaluate sex differences. Temporal trends in the numbers of participants by sex and substance use status were analyzed. We evaluated how often sex effects were appropriately analyzed and the proportion of studies that found sex by substance interactions on volumetric measures. RESULTS Female enrollment increased over time, but remained significantly lower than male enrollment (p=0.01), with the greatest bias for alcohol and opiate studies. 79% of studies included both sexes; however, 74% did not evaluate sex effects or used an analytic approach that precluded detection of sex by substance use interactions. 85% of studies that stratified by sex reported different substance effects on brain volumes. Only 33% of studies examining two-way interactions found significant interactions, highlighting that many studies were underpowered to detect interactions. CONCLUSIONS Although female participation in substance use studies of brain morphometry has increased, sex disparity persists. Studying adequate numbers of both sexes and employing correct analytic approaches is critical for understanding sex differences in brain morphometric changes in substance abuse.

Frequency based gating: An alternative, conformal, approach to 4D PET data utilization

PURPOSE Respiratory gating is a strategy for overcoming image degradation caused by patient motion in Positron Emission Tomography (PET) imaging. Traditional methods for sorting data, namely, phase-based gating or amplitude-based gating, come with an inherent trade-off between resolution improvements and added noise present in the subjugated data. If the goal of motion correction in PET is realigned from creating 4D images that attempt to mimic nongated images, towards ideal utilization of the information available, then new paths for data management emerge. In this work, the authors examine the application of a method in a new class of frequency based data subjugation algorithms, termed gating +. This strategy utilizes data driven information to locally adapt signal to its optimal segregation, thereby creating a new approach to 4D data utilization PET. METHODS 189 (18)F-fluorodeoxyglucose (FDG) PET scans were acquired at a single bed position centered on the thorax region. 4D gated image sets were reconstructed using data driven gating. The gating+ signal optimization algorithm, previously presented in small animal PET images and simulations, was used to segregate data in frequency space to generate optimized 4D images in the population-the first application and analysis of gating+ in human PET scans. The nongated, phase gated, and gating+ representations of the data were compared using FDG uptake analysis in the identified lesions and noise measurements from background regions. RESULTS Optimized processing required less than 1 min per scan on a standard PC (plus standard reconstruction time), and yielded entire 4D optimized volumes plus motion maps. Optimized scans had noise characteristics similar to nongated images, yet also contained much of the resolution and motion information found in the gated images. The average SUVmax increase in the lesion sample between gated/nongated and gating+/nongated (±SD in population) was 35.8% ± 34.6% and 28.6% ± 27.9%, respectively. The average percent standard deviation (%SD ± SD in population) in liver volumes of interest (VOIs) across the sample for the nongated, gated, and gating+ scans was 6.7% ± 2.4%, 13.6% ± 3.3%, and 7.1% ± 2.5%, respectively. In all cases, the noise in the gating+ liver VOIs was closer to the nongated measurements than to the gated. CONCLUSIONS The gating+ algorithm introduces the notion of conforming 4D data segregation to the local information and statistics that support it. By segregating data in frequency space, the authors are able to generate low noise motion information rich image sets, derived solely from selective use of raw data. Their work shows that the gating+ algorithm can be robustly applied in populations, and across varying qualities of motion and scans statistics, and be integrated as part of a fully automated motion correction workflow. Furthermore, the idea of smart signal utilization underpins a new concept of low risk or even risk-free motion correction application in PET.

Medical Student Satisfaction and Performance Using an Innovative Radiology Education Laboratory

BACKGROUND Imaging plays a critical role in the practice of modern medicine, yet it remains underrepresented in undergraduate medical education (UME) [1]. Many graduating physicians feel insufficiently trained in core radiology interpretation and utilization skills, and only 10% to 25% of US medical schools require dedicated radiology clerkships [1,2]. Challenges in imaging education include competition for time in crowded UME curricula, lack of innovative educational methods that meet the needs of millennial learners, and the integration of digital resources and technology into the educational experience [3]. Underscoring these national trends, University of Colorado School of Medicine (CUSOM) students have consistently rated the quality of their experience in radiology education lower than the national average on the Association of American Medical Colleges graduating survey. At our institution, this gap in learner satisfaction reflected an outdated curriculum that was overly reliant on passive learning in the form of didactic lectures and an observational experience gained from shadowing radiologists in the reading room. Millennial learners

Validity of Measures Assessing Oral Health Beliefs of American Indian Parents

ObjectivesThis aimed to validate measures of constructs included in an extended Health Belief Model (EHBM) addressing oral health beliefs among American Indian (AI) parents.MethodsQuestionnaire data were collected as part of a randomized controlled trial (n = 1016) aimed at reducing childhood caries. Participants were AI parents with a preschool-age child enrolled in the Navajo Nation Head Start program. Questionnaire items addressed five EHBM constructs: perceived susceptibility, severity, barriers, benefits, and parental self-efficacy. Subscales representing each construct underwent reliability and validity testing. Internal consistency reliability of each subscale was evaluated using Cronbach’s alpha. Convergent validity was assessed using linear regression to evaluate the association of each EHBM subscale with oral health-related measures.ResultsInternal consistency reliability was high for self-efficacy (α = 0.83) and perceived benefits (α = 0.83) compared to remaining EHBM subscales (α < 0.50). Parents with more education (p < 0.0001) and income (p = 0.0002) perceived dental caries as more severe younger parents (ps = 0.02) and those with more education (ps < 0.0001) perceived greater benefits and fewer barriers to following recommended oral health behavior. Female parents (p < 0.0001) and those with more education (p = 0.02) had higher levels of self-efficacy. Parental knowledge was associated with all EHBM measures (ps < 0.0001) excluding perceived susceptibility (p > 0.05). Parents with increased self-efficacy had greater behavioral adherence (p < 0.0001), whereas lower behavioral adherence was associated with parents who reported higher perceived barriers (p < 0.0001). Better pediatric oral health outcomes were associated with higher levels of self-efficacy (p < 0.0001) and lower levels of perceived severity (p = 0.02) and barriers (p = 0.05).ConclusionsResults support the value of questionnaire items addressing the EHBM subscales, which functioned in a manner consistent with the EHBM theoretical framework in AI participants.

Effect of Arrival of Prior Mammograms on Recall Negation for Screening Mammograms Performed With Digital Breast Tomosynthesis in a Clinical Setting

PURPOSE This retrospective study evaluates the effect of comparison with prior mammograms on recall negation for screening mammography performed with digital breast tomosynthesis (DBT) in a clinical setting and compares it with that performed without DBT. METHODS This is an Institutional Review Board-approved, HIPAA-compliant retrospective review of the electronic medical record for all nonbaseline screening mammograms performed in clinical practice over 13 months. For each mammogram, we recorded if DBT were used, the BI-RADS assigned at initial interpretation, and whether prior mammograms were available at initial interpretation. If prior mammograms arrived later for comparison, the final BI-RADS assigned after comparison was recorded. A mammogram assigned a BI-RADS 0 at initial interpretation and assigned a BI-RADS 1 or BI-RADS 2 after prior mammograms arrived for comparison was labeled as a recall that was negated by the arrival of prior mammograms. The number of recalls negated for mammograms that used DBT was compared with that for mammograms that did not use DBT. RESULTS Arrival of prior mammograms for comparison negated the need for recall for mammograms performed with DBT by 67.67% and negated the need for recall for mammograms performed without DBT by 55.80%. After adjusting for age, density, and time between mammograms, the percentage of recalls negated by comparison with prior mammograms was not significantly different for mammograms performed with DBT than it was for those performed without DBT. CONCLUSION Comparison with prior mammograms remains important for the minimization of recall rates during the use of DBT for screening mammography in the clinical setting.

Ultrasound and Dual-Energy X-Ray Absorptiometry Report Transcription Error Rates and Strategies for Reduction

PURPOSE Radiologists play an essential role in patient care by providing accurate and timely results. An error-free radiology report is an expectation of both patients and referring physicians. Software is currently available that can eliminate measurement and side types of errors while saving radiologists and sonographers time. The objectives of this study were to evaluate the potential reduction in report errors, estimate the potential time savings associated with implementation, and conduct a cost-benefit analysis of implementing two software programs. METHODS Data on the number of measurement errors and side errors in ultrasound and dual-energy x-ray absorptiometry reports were collected, and the time required for data entry that the software would reduce was measured by report type. Generalized estimating equations regression was used to estimate error rates and data entry times and corresponding 95% confidence intervals by report type for radiologists and sonographers. Current wages and report volumes were then applied to the time savings to estimate the annual wage savings. Projected volume increases were applied to the annual estimates to generate a 5-year savings estimate. RESULTS Overall, measurement errors occurred in 6% to 28% of ultrasound reports, depending on the report type. Side errors were rare. It was estimated that over 5 years, the software could save

Effect of Change in Portal Vein Flow Rates on Hepatic Ablations Created with a Bipolar Radiofrequency Ablation Device

693,777 in radiologist wages and

Public Reporting of MRI of the Lumbar Spine for Low Back Pain and Changes in Clinical Documentation

130,771 in sonographer wages, a total of