Accuracy and Feasibility of Three-Dimensional Ultrasound Testing in Eye Clinic and Emergency Department Patients with Vision Complaints.

BACKGROUND: Ocular emergencies comprise 2-3% of emergency department (ED) visits, with retinal detachment requiring emergency surgery. Two-dimensional ultrasound is a rapid bedside tool but is highly operator dependent. OBJECTIVE: We determined three-dimensional ultrasound (3DUS) feasibility, acceptability, and usability in eye pathology detection using the ophthalmologist examination as reference standard. METHODS: We performed a prospective, blinded cohort study of a 3DUS-enabling device in 30 eye clinic and ED patients with visual symptoms and calculated 3DUS performance characteristics. Two expert readers interpreted the 3DUS images for pathology. All participants completed surveys. RESULTS: 3DUS sensitivity was 0.81, specificity 0.73, positive predictive value 0.54, negative predictive value 0.91, and likelihood ratio (LR)+/LR- 3.03 and 0.26, respectively. Novice and expert sonographers had "substantial" agreement in correct diagnosis of abnormal vs. normal (κ = 0.68, 95% confidence interval 0.48-0.88). Most patients indicated that 3DUS is fast, comfortable, helps them understand their problem, and improves provider interaction/care, and all sonographers agreed; 4/5 sonographers felt confident performing ultrasound. Expert readers correctly identified an abnormal eye in 83/120 scans (76%) and correct diagnosis in 72/120 scans (65%), with no statistical difference between novice (79%; 69%) and expert (72%; 61%) sonographers (p = 0.39, p = 0.55), suggesting reduced operator dependence. Reader diagnosis confidence and image quality varied widely. Image acquisition times were fast for novice (mean 225 ± 83 s) and expert (201 ± 51) sonographers, with fast expert reader interpretation times (225 ± 136). CONCLUSIONS: A 3DUS-enabling device demonstrates a sensitivity of 0.81 and specificity of 0.73 for disease detection, fast image acquisition, and may reduce operator dependence for detecting emergent retinal pathologies. Further technological development is needed to improve diagnostic accuracy in identifying and characterizing retinal pathology.

A prospective blinded comparison of second trimester fetal measurements by expert and novice readers using low-cost novice-acquired 3D volumetric ultrasound.

RATIONALE AND OBJECTIVES: Two-dimensional (2D) ultrasound (US) is operator dependent, requiring operator skill and experience to selectively identify and record planes of interest for subsequent interpretation. This limits the utility of US in settings in which expert sonographers are unavailable. Three-dimensional (3D) US acquisition of an anatomic target, which enables reconstruction of any plane through the acquired volume, might reduce operator dependence by providing any desired image plane for interpretation, without identification of target planes of interest at the time of acquisition. We applied a low-cost 3DUS technology because of the wider potential application compared with dedicated 3DUS systems. We chose second trimester fetal biometric parameters for study because of their importance in maternal-fetal health globally. We hypothesized that expert and novice interpretations of novice-acquired 3D volumes would not differ from each other nor from expert measurements of expert-acquired 2D images, the clinical reference standard. MATERIALS AND METHODS: This was a prospective, blinded, observational study. Expert sonographers blinded to 3DUS volumes acquired 2DUS images of second trimester fetuses from 32 subjects, and expert readers performed interpretation, during usual care. A novice sonographer blinded to other clinical data acquired oriented 3DUS image volumes of the same subjects on the same date. Expert readers blinded to other data assessed placental location (PL), fetal presentation (FP), and amniotic fluid volume (AFV) in novice-acquired 3D volumes. Novice and expert raters blinded to other data independently measured biparietal diameter (BPD), humerus length (HL), and femur length (FL) for each fetus from novice-acquired 3D volumes. Corresponding gestational age (GA) estimates were calculated. Inter-rater reliability of measurements and GAs (expert 3D versus expert 2D, novice 3D versus expert 2D, and expert 3D versus novice 3D) were assessed by intraclass correlation coefficient (ICC). Mean inter-rater measurement differences were analyzed using one-way ANOVA. RESULTS: 3D volume acquisition and reconstruction required mean 30.4 s (±5.7) and 70.0 s (±24.0), respectively. PL, FP, and AFV were evaluated from volumes for all subjects; mean time for evaluation was 16 s (±0.0). PL, FP, and AFV could be evaluated for all subjects. At least one biometric measurement was possible for 31 subjects (97%). Agreement between rater pairs for a composite of all measures was excellent (ICCs ≥ 0.95), and for individual measures was good to excellent (ICCs ≥ 0.75). Inter-rater differences were not significant (p > .05). CONCLUSIONS: Expert and novice interpretations of novice-acquired 3DUS volumes of second trimester fetuses provided reliable biometric measures compared with expert interpretation of expert-acquired 2DUS images. 3DUS volume acquisition with a low-cost system may reduce operator dependence of ultrasound.

Versatile Low-Cost Volumetric 3-D Ultrasound Platform for Existing Clinical 2-D Systems.

Ultrasound imaging has indications across many areas of medicine, but the need for training and the variability in skill and acquired image quality among 2-D ultrasound users have limited its wider adoption and utilization. Low-cost volumetric ultrasound with a known frame of reference has the potential to lower these operator-dependent barriers and enhance the clinical utility of ultrasound imaging. In this paper, we improve upon our previous research-scanner-based prototype to implement a versatile volumetric imaging platform for existing clinical 2-D ultrasound systems. We present improved data acquisition and image reconstruction schemes to increase quality, streamline workflow, and provide real-time visual feedback. We present initial results using the platform on a Vimedix simulator, as well as on phantom and in vivo targets using a variety of clinical ultrasound systems and probes.

Low-cost Volumetric Ultrasound by Augmentation of 2D Systems: Design and Prototype.

Conventional two-dimensional (2D) ultrasound imaging is a powerful diagnostic tool in the hands of an experienced user, yet 2D ultrasound remains clinically underutilized and inherently incomplete, with output being very operator dependent. Volumetric ultrasound systems can more fully capture a three-dimensional (3D) region of interest, but current 3D systems require specialized transducers, are prohibitively expensive for many clinical departments, and do not register image orientation with respect to the patient; these systems are designed to provide improved workflow rather than operator independence. This work investigates whether it is possible to add volumetric 3D imaging capability to existing 2D ultrasound systems at minimal cost, providing a practical means of reducing operator dependence in ultrasound. In this paper, we present a low-cost method to make 2D ultrasound systems capable of quality volumetric image acquisition: we present the general system design and image acquisition method, including the use of a probe-mounted orientation sensor, a simple probe fixture prototype, and an offline volume reconstruction technique. We demonstrate initial results of the method, implemented using a Verasonics Vantage research scanner.

Versatile, Reusable, and Inexpensive Ultrasound Phantom Procedural Trainers.

We have constructed simple and inexpensive models for ultrasound-guided procedural training using synthetic ballistic gelatin. These models are durable, leak resistant, and able to be shaped to fit a variety of simulation scenarios to teach procedures. They provide realistic tactile and sonographic training for our learners in a safe, idealized setting.

Comparative Effectiveness Research: Alternatives to "Traditional" Computed Tomography Use in the Acute Care Setting.

Computed tomography (CT) scanning is an essential diagnostic tool and has revolutionized care of patients in the acute care setting. However, there is widespread agreement that overutilization of CT, where benefits do not exceed possible costs or harms, is occurring. The goal was to seek consensus in identifying and prioritizing research questions and themes that involve the comparative effectiveness of "traditional" CT use versus alternative diagnostic strategies in the acute care setting. A modified Delphi technique was used that included input from emergency physicians, emergency radiologists, medical physicists, and an industry expert to achieve this.

Cost-effective, Reusable, Leak-resistant Ultrasound-guided Vascular Access Trainer.

BACKGROUND: Ultrasound guidance for insertion of a peripheral venous catheter is becoming common practice in many emergency departments in the difficult-to-access patient, and simulation has become an important tool for health care practitioners to learn this technique. Commercial trainers are expensive, and low-cost alternatives described to date provide a sub-optimal training experience. We introduce ballistics gel as a new material for the creation of simulating phantoms. MATERIALS AND METHODS: Directions describe construction of a simulating phantom composed of 10% ballistic gelatin and commonly available latex tubing. The model's success as used by one residency training program and medical school is described. RESULTS: Cost per phantom was $22.83, with less than an hour preparation time per phantom. We found these phantoms to offer a comparable user experience to commercially available products and better than other homemade products. DISCUSSION: Ballistics gel is a novel material for production of simulation phantoms that provides a low-cost, realistic simulation experience. The clear gel material works well for novice learners, and opacifying agents can be added to increase difficulty for more advanced learners. The material offers flexibility in design to make models for a broad range of skill instruction. CONCLUSION: A relatively quick and easy process using ballistics gel allowed us to create a simulation experience similar to commercially available trainers at a fraction of the cost.

With "big data" comes big responsibility: outreach to North Carolina Medicaid patients with 10 or more computed tomography scans in 12 months.

BACKGROUND: Patients are being exposed to increasing levels of ionizing radiation, much of it from computed tomography (CT) scans. METHODS: Adults without a cancer diagnosis who received 10 or more CT scans in 2010 were identified from North Carolina Medicaid claims data and were sent a letter in July 2011 informing them of their radiation exposure; those who had undergone 20 or more CT scans in 2010 were also telephoned. The CT scan exposure of these high-exposure patients during the 12 months following these interventions was compared with that of adult Medicaid patients without cancer who had at least 1 CT scan but were not in the intervention population. RESULTS: The average number of CT scans per month for the high-exposure population decreased over time, but most of that reduction occurred 6-9 months before our interventions took place. At about the same time, the number of CT scans per month also decreased in adult Medicaid patients without cancer who had at least 1 CT scan but were not in the intervention population. LIMITATIONS: Our data do not include information about CT scans that may have been performed during times when patients were not covered by Medicaid. Some of our letters may not have been received or understood. Some high-exposure patients were unintentionally excluded from our study because organization of data on Medicaid claims varies by setting of care. CONCLUSION: Our patient education intervention was not temporally associated with significant decreases in subsequent CT exposure. Effecting behavior change to reduce exposure to ionizing radiation requires more than an educational letter or telephone call.