CT Dose Optimization in Pediatric Radiology: A Multiyear Effort to Preserve the Benefits of Imaging While Reducing the Risks.

The marked increase in radiation exposure from medical imaging, especially in children, has caused considerable alarm and spurred efforts to preserve the benefits but reduce the risks of imaging. Applying the principles of the Image Gently campaign, data-driven process and quality improvement techniques such as process mapping and flowcharting, cause-and-effect diagrams, Pareto analysis, statistical process control (control charts), failure mode and effects analysis, "lean" or Six Sigma methodology, and closed feedback loops led to a multiyear program that has reduced overall computed tomographic (CT) examination volume by more than fourfold and concurrently decreased radiation exposure per CT study without compromising diagnostic utility. This systematic approach involving education, streamlining access to magnetic resonance imaging and ultrasonography, auditing with comparison with benchmarks, applying modern CT technology, and revising CT protocols has led to a more than twofold reduction in CT radiation exposure between 2005 and 2012 for patients at the authors' institution while maintaining diagnostic utility.

Optimizing radiation use during fluoroscopic procedures: a quality and safety improvement project.

PURPOSE: The ionizing radiation used during fluoroscopically guided medical interventions carries risk. The teams performing these procedures seek to minimize those risks while preserving each procedure's benefits. This report describes a data-driven optimization strategy. METHODS: Manual and automated data capture systems were used to collect a series of different metrics, including fluoroscopy time, kerma area product, and reference point air kerma, from both adult and pediatric interventional radiologic procedures. Tools from statistical process control were used to identify opportunities for improvement and assess which changes led to improvement. RESULTS: Initial efforts focused on creating a system capable of reliably capturing fluoroscopy time from all interventional radiologic procedures. Ongoing data analysis and feedback to frontline teams led to the development of a manual workflow that reliably captured fluoroscopy time. Data capture was later supplemented by automatic capture of electronic records. This process exploited the standardized format (DICOM Structured Reporting) that newer fluoroscopy units use to record the radiation metrics. Data analysis found marked differences between the imaging protocols used for adults and children. Revision of the adult protocols led to a stable twofold reduction in average exposure per adult procedure. Analysis of balancing measures found no impact on workflow. CONCLUSIONS: A systematic approach to improving radiation use during procedures led to a substantial and sustained reduction in risk with no reduction in benefits. Data were readily captured by both manual and automated processes. Concepts from cognitive psychology and information theory provided a theoretical basis for both data analysis and improvement opportunities.

Objective assessment of operator performance during ultrasound-guided procedures.

PURPOSE: Simulation permits objective assessment of operator performance in a controlled and safe environment. Image-guided procedures often require accurate needle placement, and we designed a system to monitor how ultrasound guidance is used to monitor needle advancement toward a target. The results were correlated with other estimates of operator skill. METHODS: The simulator consisted of a tissue phantom, ultrasound unit, and electromagnetic tracking system. Operators were asked to guide a needle toward a visible point target. Performance was video-recorded and synchronized with the electromagnetic tracking data. A series of algorithms based on motor control theory and human information processing were used to convert raw tracking data into different performance indices. Scoring algorithms converted the tracking data into efficiency, quality, task difficulty, and targeting scores that were aggregated to create performance indices. After initial feasibility testing, a standardized assessment was developed. Operators (N = 12) with a broad spectrum of skill and experience were enrolled and tested. Overall scores were based on performance during ten simulated procedures. Prior clinical experience was used to independently estimate operator skill. RESULTS: When summed, the performance indices correlated well with estimated skill. Operators with minimal or no prior experience scored markedly lower than experienced operators. The overall score tended to increase according to operator's clinical experience. Operator experience was linked to decreased variation in multiple aspects of performance. The aggregated results of multiple trials provided the best correlation between estimated skill and performance. A metric for the operator's ability to maintain the needle aimed at the target discriminated between operators with different levels of experience. CONCLUSIONS: This study used a highly focused task model, standardized assessment, and objective data analysis to assess performance during simulated ultrasound-guided needle placement. The performance indices were closely related to operator experience.

Capture and analysis of data from image-guided procedures.

PURPOSE: Improvement of performance during image-guided procedures begins with close observation of existing systems. Recording of procedures and detailed analysis of those recordings may provide considerable insight into how performance might be improved. MATERIALS AND METHODS: Multiple video and audio recording devices were used to capture the stimulus/response cycles that occur during uterine artery embolization, transjugular intrahepatic portosystemic shunt creation, and Port-a-Cath placement. These records were compiled, and data regarding radiation use were extracted from each procedure. Recordings from Port-a-Cath placement were also used to assess operator performance during ultrasound (US)-guided venous access and medication handling. RESULTS: The recordings were used to assess how physicians use visual and auditory information to drive decisions during image-guided procedures. Correlating radiation dose with the modality used to acquire the image and the procedure timeline produced a series of clear patterns. Fluoroscopy was used to guide decisions during the vast majority of each procedure. Acquisition of digital subtraction angiographic images caused a substantial increase in radiation flux. There were clear instances in which the additional information provided by the increased dose was considered essential to the decision-making process, but there were also instances in which it appeared that the additional information did not drive intraprocedural decisions. Analysis of a US-guided procedure demonstrated that the physician would not advance the needle whenever its position relative to the target was uncertain. CONCLUSIONS: Analysis of these detailed recordings provided important insights into how visual information is used during image-guided procedures. The results suggest there would be considerable benefit to matching information-gathering activities to the operators' capacity to analyze information and make decisions.

Simulation in training: one-year experience using an efficiency index to assess interventional radiology fellow training status.

PURPOSE: To compare objective fellow and expert efficiency indices for an interventional radiology renal artery stenosis skill set with the use of a high-fidelity simulator. MATERIALS AND METHODS: The Mentice VIST simulator was used for three different renal artery stenosis simulations of varying difficulty, which were used to grade performance. Fellows' indices at three intervals throughout 1 year were compared to expert baseline performance. Seventy-four simulated procedures were performed, 63 of which were captured as audiovisual recordings. Three levels of fellow experience were analyzed: 1, 6, and 12 months of dedicated interventional radiology fellowship. The recordings were compiled on a computer workstation and analyzed. Distinct measurable events in the procedures were identified with task analysis, and data regarding efficiency were extracted. Total scores were calculated as the product of procedure time, fluoroscopy time, tools, and contrast agent volume. The lowest scores, which reflected efficient use of tools, radiation, and time, were considered to indicate proficiency. Subjective analysis of participants' procedural errors was not included in this analysis. RESULTS: Fellows' mean scores diminished from 1 month to 12 months (42,960 at 1 month, 18,726 at 6 months, and 9,636 at 12 months). The experts' mean score was 4,660. In addition, the range of variance in score diminished with increasing experience (from a range of 5,940-120,156 at 1 month to 2,436-85,272 at 6 months and 2,160-32,400 at 12 months). Expert scores ranged from 1,450 to 10,800. CONCLUSIONS: Objective efficiency indices for simulated procedures can demonstrate scores directly comparable to the level of clinical experience.