Quantifying cancer risk from exposures to medical imaging in the Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study: research methods and cohort profile.

PURPOSE: The Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study is quantifying the association between cumulative radiation exposure from fetal and/or childhood medical imaging and subsequent cancer risk. This manuscript describes the study cohorts and research methods. METHODS: The RIC Study is a longitudinal study of children in two retrospective cohorts from 6 U.S. healthcare systems and from Ontario, Canada over the period 1995-2017. The fetal-exposure cohort includes children whose mothers were enrolled in the healthcare system during their entire pregnancy and followed to age 20. The childhood-exposure cohort includes children born into the system and followed while continuously enrolled. Imaging utilization was determined using administrative data. Computed tomography (CT) parameters were collected to estimate individualized patient organ dosimetry. Organ dose libraries for average exposures were constructed for radiography, fluoroscopy, and angiography, while diagnostic radiopharmaceutical biokinetic models were applied to estimate organ doses received in nuclear medicine procedures. Cancers were ascertained from local and state/provincial cancer registry linkages. RESULTS: The fetal-exposure cohort includes 3,474,000 children among whom 6,606 cancers (2394 leukemias) were diagnosed over 37,659,582 person-years; 0.5% had in utero exposure to CT, 4.0% radiography, 0.5% fluoroscopy, 0.04% angiography, 0.2% nuclear medicine. The childhood-exposure cohort includes 3,724,632 children in whom 6,358 cancers (2,372 leukemias) were diagnosed over 36,190,027 person-years; 5.9% were exposed to CT, 61.1% radiography, 6.0% fluoroscopy, 0.4% angiography, 1.5% nuclear medicine. CONCLUSION: The RIC Study is poised to be the largest study addressing risk of childhood and adolescent cancer associated with ionizing radiation from medical imaging, estimated with individualized patient organ dosimetry.

Pharmacomechanical Catheter-Directed Thrombolysis for Deep-Vein Thrombosis.

BACKGROUND: The post-thrombotic syndrome frequently develops in patients with proximal deep-vein thrombosis despite treatment with anticoagulant therapy. Pharmacomechanical catheter-directed thrombolysis (hereafter "pharmacomechanical thrombolysis") rapidly removes thrombus and is hypothesized to reduce the risk of the post-thrombotic syndrome. METHODS: We randomly assigned 692 patients with acute proximal deep-vein thrombosis to receive either anticoagulation alone (control group) or anticoagulation plus pharmacomechanical thrombolysis (catheter-mediated or device-mediated intrathrombus delivery of recombinant tissue plasminogen activator and thrombus aspiration or maceration, with or without stenting). The primary outcome was development of the post-thrombotic syndrome between 6 and 24 months of follow-up. RESULTS: Between 6 and 24 months, there was no significant between-group difference in the percentage of patients with the post-thrombotic syndrome (47% in the pharmacomechanical-thrombolysis group and 48% in the control group; risk ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.11; P=0.56). Pharmacomechanical thrombolysis led to more major bleeding events within 10 days (1.7% vs. 0.3% of patients, P=0.049), but no significant difference in recurrent venous thromboembolism was seen over the 24-month follow-up period (12% in the pharmacomechanical-thrombolysis group and 8% in the control group, P=0.09). Moderate-to-severe post-thrombotic syndrome occurred in 18% of patients in the pharmacomechanical-thrombolysis group versus 24% of those in the control group (risk ratio, 0.73; 95% CI, 0.54 to 0.98; P=0.04). Severity scores for the post-thrombotic syndrome were lower in the pharmacomechanical-thrombolysis group than in the control group at 6, 12, 18, and 24 months of follow-up (P<0.01 for the comparison of the Villalta scores at each time point), but the improvement in quality of life from baseline to 24 months did not differ significantly between the treatment groups. CONCLUSIONS: Among patients with acute proximal deep-vein thrombosis, the addition of pharmacomechanical catheter-directed thrombolysis to anticoagulation did not result in a lower risk of the post-thrombotic syndrome but did result in a higher risk of major bleeding. (Funded by the National Heart, Lung, and Blood Institute and others; ATTRACT ClinicalTrials.gov number, NCT00790335 .).

Analyzing Radiation Use during Transjugular Intrahepatic Portosystemic Shunt Creation.

Portal vein access during transjugular intrahepatic portosystemic shunt creation was examined in 11 patients. Radiation metrics (kerma area product, reference point air kerma, and fluoroscopy times) during portal vein access were significantly greater for conventional versus intravascular US-guided transjugular intrahepatic portosystemic shunt (54.8 mGy ∙ cm2 ± 27.6 vs 8.4 mGy ∙ cm2 ± 5.0, P = .009; 210.4 mGy ± 109.1 vs 29.5 mGy ± 18.4, P = .009; 19.1 min ± 8.6 vs 8.9 min ± 4.6, P = .04). Wedged hepatic venography is a major contributor to radiation exposure. Intravascular US guidance is associated with significantly reduced radiation use.

Trends in Use of Medical Imaging in US Health Care Systems and in Ontario, Canada, 2000-2016.

Importance: Medical imaging increased rapidly from 2000 to 2006, but trends in recent years have not been analyzed. Objective: To evaluate recent trends in medical imaging. Design, Setting, and Participants: Retrospective cohort study of patterns of medical imaging between 2000 and 2016 among 16 million to 21 million patients enrolled annually in 7 US integrated and mixed-model insurance health care systems and for individuals receiving care in Ontario, Canada. Exposures: Calendar year and country (United States vs Canada). Main Outcomes and Measures: Use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine imaging. Annual and relative imaging rates by imaging modality, country, and age (children [<18 years], adults [18-64 years], and older adults [≥65 years]). Results: Overall, 135 774 532 imaging examinations were included; 5 439 874 (4%) in children, 89 635 312 (66%) in adults, and 40 699 346 (30%) in older adults. Among adults and older adults, imaging rates were significantly higher in 2016 vs 2000 for all imaging modalities other than nuclear medicine. For example, among older adults, CT imaging rates were 428 per 1000 person-years in 2016 vs 204 per 1000 in 2000 in US health care systems and 409 per 1000 vs 161 per 1000 in Ontario; for MRI, 139 per 1000 vs 62 per 1000 in the United States and 89 per 1000 vs 13 per 1000 in Ontario; and for ultrasound, 495 per 1000 vs 324 per 1000 in the United States and 580 per 1000 vs 332 per 1000 in Ontario. Annual growth in imaging rates among US adults and older adults slowed over time for CT (from an 11.6% annual percentage increase among adults and 9.5% among older adults in 2000-2006 to 3.7% among adults in 2013-2016 and 5.2% among older adults in 2014-2016) and for MRI (from 11.4% in 2000-2004 in adults and 11.3% in 2000-2005 in older adults to 1.3% in 2007-2016 in adults and 2.2% in 2005-2016 in older adults). Patterns in Ontario were similar. Among children, annual growth for CT stabilized or declined (United States: from 10.1% in 2000-2005 to 0.8% in 2013-2016; Ontario: from 3.3% in 2000-2006 to -5.3% in 2006-2016), but patterns for MRI were similar to adults. Changes in annual growth in ultrasound were smaller among adults and children in the United States and Ontario compared with CT and MRI. Nuclear medicine imaging declined in adults and children after 2006. Conclusions and Relevance: From 2000 to 2016 in 7 US integrated and mixed-model health care systems and in Ontario, rates of CT and MRI use continued to increase among adults, but at a slower pace in more recent years. In children, imaging rates continued to increase except for CT, which stabilized or declined in more recent periods. Whether the observed imaging utilization was appropriate or was associated with improved patient outcomes is unknown.

Overnight Resident versus 24-hour Attending Radiologist Coverage in Academic Medical Centers.

Academic medical centers have long relied on radiology residents to provide after-hours coverage, which means that they essentially function with autonomy. In this approach, attending radiologist review of resident interpretations occurs the following morning, often by subspecialist faculty. In recent years, however, this traditional coverage model in academic radiology departments has been challenged by an alternative model, the 24-hour attending radiologist coverage. Proponents of this new model seek to improve patient care after hours by increasing report accuracy and the speed with which the report is finalized. In this article, we review the traditional and the 24-hour attending radiologist coverage models. We summarize previous studies that indicate that resident overnight error rates are sufficiently low so that changing to an overnight attending model may not necessarily provide a meaningful increase in report accuracy. Whereas some centers completely replaced overnight residents, we note that most centers use a hybrid model, and overnight residents work alongside supervising attending radiologists, much as they do during the day. Even in this hybrid model, universal double reading and subspecialist final review, typical features of the traditional autonomous resident coverage model, are generally sacrificed. Because of this, changing from resident coverage to coverage by an attending radiologist that is 24 hours/day, 7 days/week may actually have detrimental effects to patient safety and quality of care provided. Changing to an overnight attending radiologist model may also have negative effects on the quality of radiology resident training, and it significantly increases cost.

Guide to effective quality improvement reporting in radiology.

Substantial societal investments in biomedical research are contributing to an explosion in knowledge that the health delivery system is struggling to effectively implement. Managing this complexity requires ingenuity, research and development, and dedicated resources. Many innovative solutions can be found in quality improvement (QI) activities, defined as the "systematic, data-guided activities designed to bring about immediate, positive changes in the delivery of healthcare in particular settings." QI shares many similarities with biomedical research, but also differs in several important ways. Inclusion of QI in the peer-reviewed literature is needed to foster its advancement through the dissemination, testing, and refinement of theories, methods, and applications. QI methods and reporting standards are less mature in health care than those of biomedical research. A lack of widespread understanding and consensus regarding the purpose of publishing QI-related material also exists. In this document, guidance is provided in evaluating quality of QI-related material and in determining priority of submitted material for publication.

Endovascular treatment of superior mesenteric artery pseudoaneurysms using covered stents in six patients.

OBJECTIVE: The objective of our study was to evaluate our experience with the use of endovascular treatments for superior mesenteric artery (SMA) pseudoaneurysms using covered stents. MATERIALS AND METHODS: Between 2002 and 2011, six patients (mean age, 41.7 years; range, 23-65 years) with SMA pseudoaneurysms were treated percutaneously with the placement of covered stents at our institution. The causes of SMA pseudoaneurysms were penetrating trauma (n = 2), blunt trauma (n = 1), and previous surgical procedures (n = 3). The mean diameter of the SMA pseudoaneurysms was 16 mm (range, 4-24 mm). Technical success and clinical success were retrospectively analyzed. RESULTS: Immediate technical success, defined as exclusion of the pseudoaneurysm and lack of active extravasation, was achieved in all six patients. Secondary balloon angioplasty was needed in one patient with residual narrowing. There was a small dissection of the proximal SMA necessitating placement of a second bare stent across the dissection. A second covered stent (Fluency stent, 8 mm) was placed in the same patient because of recurrent bleeding due to a type II endoleak 5 days after the first covered stent had been placed. This patient had no subsequent episodes of bleeding or bowel ischemia. Follow-up CT in the remaining five patients (mean, 21 months; range, 1-58 months) confirmed stent patency and preserved distal arterial flow to the bowel without episodes of bleeding or bowel ischemia during follow-up (mean, 27 months; range, 11-58 months). CONCLUSION: Percutaneous endovascular treatment using a covered stent may be a safe and feasible tool for SMA pseudoaneurysms.

Special article: retained guidewires after intraoperative placement of central venous catheters.

Guidewire retention is a rare complication of central venous catheter placement, and has been related to operator fatigue, inexperience, and inattention, and inadequate supervision of trainees. The true incidence of guidewire loss after intraoperative placement of central venous catheters is unknown. We report 4 cases of guidewire loss after central venous access procedures performed by anesthesia providers in the operating room. Worsening of patients' clinical condition during catheter placement and complex procedures necessitating more than one guidewire insertion are recurring scenarios in cases involving guidewire loss. Over 6 years at our institution, intraoperative wire loss occurred at a rate of 1:3291 procedures (95% confidence interval of 1/10,000 to 8/10,000).

Associated radiation exposure from medical imaging and excess lifetime risk of developing cancer in pediatric patients with pulmonary hypertension.

Pediatric patients with pulmonary hypertension (PH) receive imaging studies that use ionizing radiation (radiation) such as computed tomography (CT) and cardiac catheterization to guide clinical care. Radiation exposure is associated with increased cancer risk. It is unknown how much radiation pediatric PH patients receive. The objective of this study is to quantify radiation received from imaging and compute associated lifetime cancer risks for pediatric patients with PH. Electronic health records between 2012 and 2022 were reviewed and radiation dose data were extracted. Organ doses were estimated using Monte Carlo modeling. Cancer risks for each patient were calculated from accumulated exposures using National Cancer Institute tools. Two hundred and forty-nine patients with PH comprised the study cohort; 97% of patients had pulmonary arterial hypertension, PH due to left heart disease, or PH due to chronic lung disease. Mean age at the time of the first imaging study was 2.5 years (standard deviation [SD] = 4.9 years). Patients underwent a mean of 12 studies per patient per year, SD = 32. Most (90%) exams were done in children <5 years of age. Radiation from CT and cardiac catheterization accounted for 88% of the total radiation dose received. Cumulative mean effective dose was 19 mSv per patient (SD = 30). Radiation dose exposure resulted in a mean increased estimated lifetime cancer risk of 7.6% (90% uncertainty interval 3.0%-14.2%) in females and 2.8% (1.2%-5.3%) in males. Careful consideration for the need of radiation-based imaging studies is warranted, especially in the youngest of children.

Improving team performance during the preprocedure time-out in pediatric interventional radiology.

BACKGROUND: The preprocedure time-out is a high-profile safety measure, and compliance is coming under increasing scrutiny. A checklist-based scoring system was developed to rigorously assess compliance, and a system of video monitoring and feedback was used to track performance and improve the time-out process in pediatric interventional radiology. METHODS: A time-out "script" containing a series of observable behaviors to be performed collectively by the physician, nurse, and technologist before each interventional procedure was used to create a checklist. A procedure room equipped with an audio/video recording system allowed capture of time-outs for later review. The reviewer scored one or two time-outs each week, and the results were posted to provide feedback. RESULTS: The process of continual feedback and modification led to substantial improvements in time-out performance during a three-year period. Analysis of subscores revealed common failure modes that were subsequently addressed. The scoring checklist was also modified after analysis suggested redundant or unnecessary items. Gains were noted in the efficiency of the time-out protocol, which took more than 1 minute in the initial stages but soon shortened to 30-45 seconds as the team gained experience. Assessment of scoring consistency across three independent observers revealed 93% interobserver agreement and 95% intraobserver agreement. Clarification of the scoring criteria led to improved consistency (97% and 98% inter- and intraobserver agreement, respectively). CONCLUSIONS: The combination of a time-out checklist, recorded procedures, review, and feedback produced not only improvements in time-out performance but also improvements in the scoring system and time-out process.

Flight data recorder for interventional radiology.

To test process improvement strategies, a recording system in a new pediatric interventional radiology suite was installed modeled after the flight data recorders found in modern aviation. Using the resulting data from these recordings, a variety of quality and safety improvement projects were planned including improving timeout performance and optimizing radiation use. There were several challenges, including balancing the need to protect patients during efforts to improve teamwork. However, the flight data recorder drove home the notion that interventional radiology is a team sport and that improvements can be measured by keeping score.

Management of excluded bile ducts in paediatric orthotopic liver transplant recipients of technical variant allografts.

BACKGROUND: A strategy to increase the number of size- and weight-appropriate organs and decrease the paediatric waiting list mortality is wider application of sectional orthotopic liver transplantation (OLT). These technical variants consist of living donor, deceased donor reduced and split allografts. However, these grafts have an increased risk of biliary complications. An unusual and complex biliary complication which can lead to graft loss is inadvertent exclusion of a major segmental bile duct. We present four cases and describe an algorithm to correct these complications. METHODS: A retrospective review of the paediatric orthotopic liver transplantation database (2000-2010) at Washington University in St. Louis/St. Louis Children's Hospital was conducted. RESULTS: Sixty-eight patients (55%) received technical variant allografts. Four complications of excluded segmental bile ducts were identified. Percutaneous cholangiography provided diagnostic confirmation and stabilization with external biliary drainage. All patients required interval surgical revision of their hepaticojejunostomy for definitive drainage. Indwelling biliary stents aided intra-operative localization of the excluded ducts. All allografts were salvaged. DISCUSSION: Aggressive diagnosis, percutaneous decompression and interval revision hepaticojejunostomy are the main tenets of management of an excluded bile duct. Careful revision hepaticojejunostomy over a percutaneous biliary stent can result in restoration of biliary continuity and allograft survival.

The biodistribution of [153Gd]Gd-labeled magnetic resonance contrast agents in a transgenic mouse model of renal failure differs greatly from control mice.

Nephrogenic systemic fibrosis occurs in renally impaired patients who have undergone contrast enhanced MR examination using intravenous gadolinium-based contrast agents. The effect of impaired kidney function on the biodistribution of gadolinium-based contrast agents was investigated using radiolabeled (153/Nat) gadolinium-DOTA, (153/Nat) gadolinium-DTPA, and (153/Nat) gadolinium-DTPA-BMA in a transgenic mouse model of renal impairment. Renally impaired animals had more activity associated with their tissues than did control mice, and this increase varied according to the radiotracer injected. For example, after 7 days, renally impaired animals that received (153/Nat) Gd-DOTA had 3-fold (P < 0.037) more activity in their bone tissue, whereas renally impaired animals receiving (153/Nat) Gd-DTPA and (153/Nat) Gd-DTPA-BMA had 8-fold (P < 0.0001) and 24-fold (P < 0.0001) more activity in their bone tissue, respectively. These findings demonstrate that renal impairment dramatically alters the tissue distribution of Gd(3+) ions in vivo, which are likely a critical factor in the development of nephrogenic systemic fibrosis.

Audio and video recording system for routine documentation of fluoroscopic procedures.

Because aviation and other reliable systems routinely record and analyze performance, the authors investigated the feasibility and utility of installing a system capable of recording image-guided procedures. An audio/video recording system adapted from those used in simulation laboratories was installed in a new pediatric interventional radiology suite. In this report, the authors describe the recording system as well as how it can be used to study radiation use during individual procedures. These results illustrate how routinely recording more than 300 procedures during the past 14 months and the detailed analysis of selected recordings can provide insights that lead to continual improvements in performance.

Improving quality and patient safety by minimizing unnecessary variation.

Quality and safety in health care have proven difficult to precisely define and measure. In other fields, quality is defined as the absence of unnecessary variation and process improvement efforts are gauged by their ability to reduce variation. This article explores how this definition can be applied to various attributes of image-guided procedures.

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.

Trends in Medical Imaging During Pregnancy in the United States and Ontario, Canada, 1996 to 2016.

Importance: The use of medical imaging has sharply increased over the last 2 decades. Imaging rates during pregnancy have not been quantified in a large, multisite study setting. Objective: To evaluate patterns of medical imaging during pregnancy. Design, Setting, and Participants: A retrospective cohort study was performed at 6 US integrated health care systems and in Ontario, Canada. Participants included pregnant women who gave birth to a live neonate of at least 24 weeks' gestation between January 1, 1996, and December 31, 2016, and who were enrolled in the health care system for the entire pregnancy. Exposures: Computed tomography (CT), magnetic resonance imaging, conventional radiography, angiography and fluoroscopy, and nuclear medicine. Main Outcomes and Measures: Imaging rates per pregnancy stratified by country and year of child's birth. Results: A total of 3 497 603 pregnancies in 2 211 789 women were included. Overall, 26% of pregnancies were from US sites. Most (92%) were in women aged 20 to 39 years, and 85% resulted in full-term births. Computed tomography imaging rates in the United States increased from 2.0 examinations/1000 pregnancies in 1996 to 11.4/1000 pregnancies in 2007, remained stable through 2010, and decreased to 9.3/1000 pregnancies by 2016, for an overall increase of 3.7-fold. Computed tomography rates in Ontario, Canada, increased more gradually by 2.0-fold, from 2.0/1000 pregnancies in 1996 to 6.2/1000 pregnancies in 2016, which was 33% lower than in the United States. Overall, 5.3% of pregnant women in US sites and 3.6% in Ontario underwent imaging with ionizing radiation, and 0.8% of women at US sites and 0.4% in Ontario underwent CT. Magnetic resonance imaging rates increased steadily from 1.0/1000 pregnancies in 1996 to 11.9/1000 pregnancies in 2016 in the United States and from 0.5/1000 pregnancies in 1996 to 9.8/1000 pregnancies in 2016 in Ontario, surpassing CT rates in 2013 in the United States and in 2007 in Ontario. In the United States, radiography rates doubled from 34.5/1000 pregnancies in 1996 to 72.6/1000 pregnancies in 1999 and then decreased to 47.6/1000 pregnancies in 2016; rates in Ontario slowly increased from 36.2/1000 pregnancies in 1996 to 44.7/1000 pregnancies in 2016. Angiography and fluoroscopy and nuclear medicine use rates were low (5.2/1000 pregnancies), but in most years, higher in Ontario than the United States. Imaging rates were highest for women who were younger than 20 years or aged 40 years or older, gave birth preterm, or were black, Native American, or Hispanic (US data only). Considering advanced imaging only, chest imaging of pregnant women was more likely to use CT in the United States and nuclear medicine imaging in Ontario. Conclusions and Relevance: The use of CT during pregnancy substantially increased in the United States and Ontario over the past 2 decades. Imaging rates during pregnancy should be monitored to avoid unnecessary exposure of women and fetuses to ionizing radiation.