The ACR Learning Network: Facilitating Local Performance Improvement Through Shared Learning.

PURPOSE: The ACR Learning Network was established to test the viability of the learning network model in radiology. In this report, the authors review the learning network concept, introduce the ACR Learning Network and its components, and report progress to date and plans for the future. METHODS: Patterned after institutional programs developed by the principal investigator, the ACR Learning Network was composed of four distinct improvement collaboratives. Initial participating sites were solicited through broad program advertisement. Candidate programs were selected on the basis of assessments of local leadership support, experience with quality improvement initiatives, intraorganizational relationships, and access to data and analytic support. Participation began with completing a 27-week formal quality improvement training and project support program, with local teams reporting weekly progress on a common performance measure. RESULTS: Four improvement collaborative topics were chosen for the initial cohort with the following numbers of participating sites: mammography positioning (6), prostate MR image quality (6), lung cancer screening (6), and follow-up on recommendations for management of incidental findings (4). To date, all sites have remained actively engaged and have progressed in an expected fashion. A detailed report of the results of the improvement phase will be provided in a future publication. CONCLUSIONS: To date, the ACR Learning Network has successfully achieved planned milestones outlined in the program's plan, with preparation under way for the second and third cohorts. By providing a shared platform for improvement training and knowledge sharing, the authors are optimistic that the network may facilitate widespread performance improvement in radiology on a number of topics for years to come.

Blueprint for Implementing and Improving Eligible Inferior Vena Cava Filter Retrieval Across Institutions.

Introduction: Placement of removable inferior vena cava filters (rIVCFs) has increased, but this has not been accompanied by timely removal, with retrieval rates as low as 8.5% at some institutions. Failure to remove rIVCFs that were not medically necessary resulted in increased complications. This study discussed the development of an inferior vena cava (IVC) filter follow-up protocol. Methods: A method to monitor IVC filter placement and retrieval was developed. A weekly report was generated detailing placement and removal of rIVCFs. A standardized retrieval calculator was utilized to determine efficacy of removal. An IVC filter Retrieval Assessment Form was developed. Managing physicians and patients with medically unnecessary filters were sent letters with a retrieval checklist and order form. If not removed within one year, additional letters were sent. Standardized IVC filter reporting templates were created and utilized after insertion of all filters with retrieval status. Letters eventually were built into the electronic medical record for direct routing. Results: From 2015 to 2020, IVC filters were placed in 719 patients. Of those, 58% were eligible for retrieval. Initial rates of rIVCF removal in eligible patients were as low as 30-33% in 2015. The retrieval rate of eligible filters rose to 44% in September 2018. The rate of retrieval rose to 61% in January 2021. Conclusions: Employing a systemic protocol to aid in follow-up of patients following rIVCF placement may improve rates of retrieval. Regular evaluation and revision of the process demonstrated a significant role in achieving an increase in retrieval rates.

Improving appropriate imaging for non-specific low back pain.

Non-specific low back pain (LBP) is a common condition in the USA, with approximately 80% of adults who will have LBP at some point during their life and roughly 30% of the adult population suffering from LBP at any given time. Although LBP is the most common cause of disability in the USA, it often has no identifiable anatomic or physiologic cause. Many patients seeking care for non-specific LBP receive X-rays and other imaging studies. However, for most acute LBP patients, symptoms resolve within 4 weeks and the use of routine imaging may result in unnecessary radiation exposure and add unnecessary costs and wasted time for patients without contributing to patient outcomes. The specific aim of the quality improvement (QI) project was to determine the effect of a multicomponent intervention to enhance the appropriate imaging utilisation for acute LBP to ≥90%. During the first 6 months of the QI project, 191 patients with LBP were seen. Of those patients, 156 (81.7%) received appropriate imaging over the 6-month intervention period, missing our targeted goal. Furthermore, this rate declined to baseline values after termination of the intervention, suggesting the need for additional prompts to sustain the initial intervention effect. Following a health system-wide deployment of practice-based alerts and quality score cards, the appropriate utilisation rate increased again and quickly to the target rate of 90%. To reduce variability in our clinical practice and to sustain an appropriate utilisation rate will require continued work. Health systems must find efficient methods to reduce LBP imaging and increase appropriate management of non-specific LBP in primary care. Increasing concordance with imaging guidelines can lessen harm associated with unnecessary radiation exposure and result in significant cost savings.

Regulatory Frameworks for Development and Evaluation of Artificial Intelligence-Based Diagnostic Imaging Algorithms: Summary and Recommendations.

Although artificial intelligence (AI)-based algorithms for diagnosis hold promise for improving care, their safety and effectiveness must be ensured to facilitate wide adoption. Several recently proposed regulatory frameworks provide a solid foundation but do not address a number of issues that may prevent algorithms from being fully trusted. In this article, we review the major regulatory frameworks for software as a medical device applications, identify major gaps, and propose additional strategies to improve the development and evaluation of diagnostic AI algorithms. We identify the following major shortcomings of the current regulatory frameworks: (1) conflation of the diagnostic task with the diagnostic algorithm, (2) superficial treatment of the diagnostic task definition, (3) no mechanism to directly compare similar algorithms, (4) insufficient characterization of safety and performance elements, (5) lack of resources to assess performance at each installed site, and (6) inherent conflicts of interest. We recommend the following additional measures: (1) separate the diagnostic task from the algorithm, (2) define performance elements beyond accuracy, (3) divide the evaluation process into discrete steps, (4) encourage assessment by a third-party evaluator, (5) incorporate these elements into the manufacturers' development process. Specifically, we recommend four phases of development and evaluation, analogous to those that have been applied to pharmaceuticals and proposed for software applications, to help ensure world-class performance of all algorithms at all installed sites. In the coming years, we anticipate the emergence of a substantial body of research dedicated to ensuring the accuracy, reliability, and safety of the algorithms.

Incidental Breast Cancer on Chest CT: Is the Radiology Report Enough?

OBJECTIVE: To determine the frequency of incidental breast findings reported on chest CT for which breast imaging follow-up is recommended, the follow-up adherence rate, and the breast malignancy rate. The relationship between strength of recommendation verbiage and follow-up was also explored. METHODS: A retrospective review was conducted of chest CT reports from July 1, 2018, to June 30, 2019, to identify those with recommendation for breast imaging follow-up. Patients with recently diagnosed or prior history of breast malignancy were excluded. Medical records were reviewed to evaluate patient adherence to follow-up, subsequent BI-RADS assessment, and diagnosis (if tissue sampling performed). Adherence was defined as diagnostic breast imaging performed within 6 months of CT recommendation. Chi-square and Mann-Whitney U tests were used to determine statistical significance of categorical and continuous variables, respectively. RESULTS: A follow-up recommendation for breast imaging was included in chest CT reports of 210 patients; 23% (48/210) returned for follow-up breast imaging. All patients assessed as BI-RADS 4 or 5 underwent image-guided biopsy. Incidental breast cancer was diagnosed in 15% (7/48) of patients who underwent follow-up breast imaging as a result of a CT report recommendation and 78% (7/9) of patients undergoing biopsy. There was no significant difference in follow-up adherence when comparing report verbiage strength. CONCLUSION: It is imperative that incidental breast findings detected on chest CT undergo follow-up breast imaging to establish accurate and timely diagnosis of breast malignancy. Outreach to referring providers and patients may have greater impact on the diagnosis of previously unsuspected breast cancer.

Closing the Loop-A Pilot in Health System Improvement.

A significant number of patients are reported to not receive timely completion of their recommended follow-up intervention following the interpretation of their imaging studies, contributing to patient deaths resulting from inaccurate or delayed diagnosis. Though automated critical test notification systems and computerized communication mechanisms currently exist, many institutions are discovering that there continue to be gaps in the completion of follow-up recommendations. Herein, we describe how we developed and implemented a closed-loop program dedicated to identifying such gaps and ensuring patients were aware of and received appropriate follow-up.

Reducing radiation exposure with iterative reconstruction: an inter- and intra-scanner analysis.

Our purpose in this study was to compare delivered radiation exposure via computed tomography dose index volume (CTDIvol) and dose length production (DLP) measurements from computed tomography (CT) examinations performed on scanners with and without image-quality enhancing iterative reconstruction (IR) software. A retrospective analysis was conducted on randomly selected chest, abdomen, and/or pelvis CT examinations from three different scanners from 1 January 2013 to 31 December 2013. CTDIvol and DLP measurements were obtained from two CT scanners with and one CT scanner without IR software. To evaluate inter-scanner variability, we compared measurements from the same model CT scanners, one with and one without IR software. To evaluate intra-scanner variability, we compared measurements between two scanners with IR software from different manufacturers. CT scanners with IR software aided in the overall reduction in radiation exposure, measured as CTDIvol by 30% and DLP by 39% when compared to a scanner without IR. There was no significant difference in CTDlvol or DLP measurements across different manufacturers with IR software. As a result, IR software significantly decreased the radiation exposure to patients, but there were no differences in radiation measurements across CT manufacturers with IR software.

Magnetic resonance imaging findings of central nervous system in lysosomal storage diseases: A pictorial review.

Lysosomal storage diseases (LSD) are a complex group of genetic disorders that are a result of inborn errors of metabolism. These errors result in a variety of metabolic dysfunction and build-up certain molecules within the tissues of the central nervous system (CNS). Although, they have discrete enzymatic deficiencies, symptomology and CNS imaging findings can overlap with each other, which can become challenging to radiologists. The purpose of this paper is to review the most common CNS imaging findings in LSD in order to familiarize the radiologist with their imaging findings and help narrow down the differential diagnosis.

Congenital anomalies of lumbosacral spine: A pictorial review.

Congenital malformations of the lumbosacral spine include spinal dysraphism and caudal anomalies. Most often, these malformations are discovered prenatally or in early infancy, but some are not diagnosed until late childhood or adulthood. The purpose of this pictorial review is to illustrate the multi-modality imaging characteristics in these complex anomalies and to provide a systematic radiological approach aiming at improving diagnostic accuracy.

Transcranial Doppler screening in sickle cell disease: The implications of using peak systolic criteria.

AIM: To compare time average maximum mean velocity (TAMV) and peak systolic velocity (PSV) criteria of Trans Cranial Doppler (TCD) in their ability to predict abnormalities on magnetic resonance imaging (MRI)/magnetic resonance angiogram (MRA) in patients with sickle cell disease. METHODS: A retrospective evaluation was performed of the outcomes in all patients with a Transcranial Doppler examination at our institution since the implementation of the hospital picture archiving and communication system (PACS) system in January 2003 through December 2012. All ultrasound imaging exams were performed by the same technologist with a 3 MHz transducer. Inclusion criteria was based upon the Transcranial Doppler procedure code in our PACS which had an indication of sickle cell disease in the history. The patient's age and gender along with the vessel with the highest time averaged mean velocity as well as the highest peak systolic velocity was recorded for analysis. A subset of the study cohort also had subsequent MR imaging and Angiograms performed within 6 mo of the TCD examination. MRI results were categorized as having a disease related abnormality (vessel narrowing, collateral formation/moya-moya, or abnormal fluid attenuation inversion recovery signal in parenchyma indicative of prior stroke) or normal. The MRI results formed the comparison standards for TCD exams in evaluating intracranial injury. Sensitivity and specificity for the two TCD criteria (TAMV and PSV) were calculated to determine which could be a better predictor for intracranial vasculopathy /clinically occult strokes. RESULTS: The study cohort for our institution was 110 patients with a total of 291 TCD examinations. These patients had a mean age of 7.6 years with a range from 2-18 years of age. Sixty-two of the 110 patients (56%) had two or more TCD exams. Thirty-seven patients (34%) had at least one MRI following a TCD examination. Of the 291 TCD examinations, 46 (16%) were conditional or abnormal by TAMV criteria. One hundred and sixteen (40%) were conditional or abnormal by PSV criteria. All studies that were abnormal by TAMV were also abnormal by PSV criteria. Seventy of the 116 (60%) studies which were conditional or abnormal by peak systolic criteria would not have been identified by time averaged mean maximum velocity criteria. The most frequent location of highest velocity measurement was noted to be in the middle cerebral artery regardless of whether it was measured by PSV or TAMV. From the 37 patients having one or more MRIs, 43 MRI exams were performed within 6 mo of a TCD examination. Twenty two (51%) MRIs had a disease related abnormality reported. When evaluating conditional or abnormal exams by PSV criteria against follow-up MRI/MRA, the sensitivity was 73% [16/(16 + 6)] and specificity was 81% [17/(4 + 17)]. When evaluating conditional or abnormal exams by TAMV criteria by follow-up MRI/MRA as the gold standard, the sensitivity was 41% [9/(9 + 13)] and the specificity was 100% [21/(21 + 0)]. In using conditional or abnormal criteria from PSV and TAMV to predict abnormalities on follow-up MRI/MR Angiogram, PSV was more sensitive (73% vs 41%) while TAMV was more specific (100% vs 81%). CONCLUSION: Based on the data obtained at our institution and using the assumption that the best screening test is the one with the highest sensitivity, the peak systolic velocity could be the measurement of choice for TCD screening.

Isolated filar cyst on lumbar spine sonography in infants: a case-control study.

BACKGROUND: Simple cysts found within the filum terminale of infants on lumbar spine sonography are relatively common, but no study has established their clinical significance. OBJECTIVE: To obtain information on the sonographic features of isolated filar cysts and determine their clinical significance in comparison with age- and sex-matched controls. MATERIALS AND METHODS: We performed a retrospective review of 644 consecutive spine sonograms in patients younger than 8 months. Gestational age- and sex-matched controls with normal lumbar sonograms were taken from the same period. We obtained short-term clinical follow-up of motor milestones for each group. RESULTS: The incidence of filar cyst was 78 of the 644 (11.8%) and was inversely related to age. Developmental follow-up of the study patients compared with control population showed no statistically significant difference in the ages at which the infants were able to turn over, crawl and walk. Follow-up MR imaging of 13 study patients (19%) failed to demonstrate filar cysts previously identified on sonography. CONCLUSION: No significant difference was found in the short-term outcome of infants with isolated filar cysts on lumbar sonography compared with that of a control population. Filar cysts should be considered a normal variant when found in isolation on lumbar sonography.

Transitions in replication timing in a 340 kb region of human chromosomal R-Band 1p36.1.

DNA replication is initiated within a few chromosomal bands as normal human fibroblasts enter the S phase. In the present study, we determined the timing of replication of sequences along a 340 kb region in one of these bands, 1p36.13, an R band on chromosome 1. Within this region, we identified a segment of DNA (approximately 140 kb) that is replicated in the first hour of the S phase and is flanked by segments replicated 1-2 h later. Using a quantitative PCR-based assay to measure sequence abundance in size-fractionated (900-1,700 nt) nascent DNA, we mapped two functional origins of replication separated by 54 kb and firing 1 h apart. One origin was found to be functional during the first hour of S and was located within a CpG island associated with a predicted gene of unknown function (Genscan NT_004610.2). The second origin was activated in the second hour of S and was mapped to a CpG island near the promoter of the aldehyde dehydrogenase 4A1 (ALDH4A1) gene. At the opposite end of the early replicating segment, a more gradual change in replication timing was observed within the span of approximately 100 kb. These data suggest that DNA replication in adjacent segments of band 1p36.13 is organized differently, perhaps in terms of replicon number and length, or rate of fork progression. In the transition areas that mark the boundaries between different temporal domains, the replication forks initiated in the early replicated region are likely to pause or delay progression before replication of the 340 kb contig is completed.