Diagnostic radiation exposure of injury patients in the emergency department: a cross-sectional large scaled study

Patterns of computed tomography utilisation in injury management: latent classes approach using linked administrative data in Western Australia

PURPOSE

Whilst computed tomography (CT) imaging has been a vital component of injury management, its increasing use has raised concern regarding ionising radiation exposure. This study aims to identify latent classes (underlying patterns) of CT use over a 3-year period following the incidence of injury and factors predicting the observed patterns.

METHOD

A retrospective observational cohort study was conducted in 21,544 individuals aged 18 + years presenting to emergency departments (ED) of four tertiary public hospitals with new injury in Western Australia. Mixture modelling approach was used to identify latent classes of CT use over a 3-year period post injury.

RESULTS

Amongst injured people with at least one CT scan, three latent classes of CT use were identified including a: temporarily high CT use (46.4%); consistently high CT use (2.6%); and low CT use class (51.1%). Being 65 + years or older, having 3 + comorbidities, history with 3 + hospitalisations and history of CT use before injury were associated with consistently high use of CT. Injury to the head, neck, thorax or abdomen, being admitted to hospital after the injury and arriving to ED by ambulance were predictors for the temporarily high use class. Living in areas of higher socio-economic disadvantage was a unique factor associated with the low CT use class.

CONCLUSIONS

Instead of assuming a single pattern of CT use for all patients with injury, the advanced latent class modelling approach has provided more nuanced understanding of the underlying patterns of CT use that may be useful for developing targeted interventions.

Pelvic radiation dose measurement for trauma patients in multifield radiographic examinations: A phantom-based TLD dosimetry study

BACKGROUND AND AIMS

Trauma patients often suffer from multiple injuries and require undergoing various radiography which is referred to as multifield radiographic examinations. Protective measures may be ignored for these examinations due to stressful emergency situations or patients' conditions. This study was conducted to evaluate the scattered doses received by the pelvis during different common multifield radiographic examinations with an emphasis on field size adjustment.

METHODS

A whole-body phantom, PBU-50, resembling the body mass, was used to carry out the common examinations for trauma patients (extremities, skull, chest, abdomen, pelvis, femur, and lumbar radiography), using a Pars Pad X-ray machine. To measure the primary entrance skin doses, three calibrated GR 200 thermoluminescence dosimeter (TLD) chips were placed in the central X-ray beam of scanned organs. Three TLDs were also placed on the pelvis symphysis pubis to measure the scattered dose received by the pelvis due to each carried-out radiography for standard and clinically used field sizes. A Harshaw 3500 TLD Reader was used to read the chips. TLD readouts (nano-Coulomb) were converted to dose (milli Gray [mGy]) using the predefined calibration curve.

RESULTS

The scattered doses to the pelvis due to scanning a single organ differed from 0.80 to 1.70, and 0.82 to 4.09 mGy for standard and clinically used field sizes, respectively. The scattered doses to the pelvis in multifield examinations varied from 0.80 to 8.43 and 0.82 to 13.6 mGy for standard and clinically used field sizes, respectively, depending on the number of scanned organs and their distances from the pelvis.

CONCLUSIONS

Multiple and repeated radiographs combined with insufficient protective measures can increase the patient's dose. The findings indicate that the scattered doses received by the pelvis can exceed the reference values in multifield radiography, especially if the radiation field is not restricted properly to the scanned organ.

Radiation protection perspective to recurrent medical imaging: what is known and what more is needed?

This review summarises the current knowledge about recurrent radiological imaging and associated cumulative doses to patients. The recent conservative estimates are for around 0.9 million patients globally who cumulate radiation doses above 100 mSv, where evidence exists for cancer risk elevation. Around one in five is estimated to be under the age of 50. Recurrent imaging is used for managing various health conditions and chronic diseases such as malignancies, trauma, end-stage kidney disease, cardiovascular diseases, Crohn's disease, urolithiasis, cystic pulmonary disease. More studies are needed from different parts of the world to understand the magnitude and appropriateness. The analysis identified areas of future work to improve radiation protection of individuals who are submitted to frequent imaging. These include access to dose saving imaging technologies; improved imaging strategies and appropriateness process; specific optimisation tailored to the clinical condition and patient habitus; wider utilisation of the automatic exposure monitoring systems with an integrated option for individual exposure tracking in standardised patient-specific risk metrics; improved training and communication. The integration of the clinical and exposure history data will support improved knowledge about radiation risks from low doses and individual radiosensitivity. The radiation protection framework will need to respond to the challenge of recurrent imaging and high individual doses. The radiation protection perspective complements the clinical perspective, and the risk to benefit analysis must account holistically for all incidental and long-term benefits and risks for patients, their clinical history and specific needs. This is a step toward the patient-centric health care.

DIAGNOSTIC IMAGING AND IONIZING RADIATION EXPOSURE IN A LEVEL 1 TRAUMA CENTRE POPULATION MET WITH TRAUMA TEAM ACTIVATION: A ONE-YEAR PATIENT RECORD AUDIT

This audit describes ionizing and non-ionizing diagnostic imaging at a regional trauma centre. All 144 patients (males 79.2%, median age 31 years) met with trauma team activation from 1 January 2015 to 31 December 2015 were included. We used data from electronic health records to identify all diagnostic imaging and report radiation exposure as dose area product (DAP) for conventional radiography (X-ray) and dose length product (DLP) and effective dose for CT. During hospitalization, 134 (93.1%) underwent X-ray, 122 (84.7%) CT, 92 (63.9%) focused assessment with sonography for trauma (FAST), 14 (9.7%) ultrasound (FAST excluded) and 32 (22.2%) magnetic resonance imaging. One hundred and sixteen (80.5%) underwent CT examinations during trauma admissions, and 73 of 144 (50.7%) standardized whole body CT (SWBCT). DAP values were below national reference levels. Median DLP and effective dose were 2396 mGycm and 20.42 mSv for all CT examinations, and 2461 mGycm (national diagnostic reference level 2400) and 22.29 mSv for a SWBCT.

Low-Dose CT With the Adaptive Statistical Iterative Reconstruction V Technique in Abdominal Organ Injury: Comparison With Routine-Dose CT With Filtered Back Projection

OBJECTIVE. The purpose of this study was to evaluate and compare the diagnostic performance and image quality of low-dose CT performed with adaptive statistical iterative reconstruction (ASIR)-V with those of routine-dose CT with filtered back projection (FBP) in the evaluation of abdominal organ injury. MATERIALS AND METHODS. The study enrolled 197 patients with trauma who underwent multiphase abdominal CT, including routine-dose portal venous phase imaging with FBP and low-dose delayed phase imaging with 50% ASIR-V. The presence of abdominal organ injuries (liver, spleen, pancreas, kidney) was reviewed, and injuries were graded according to American Association for the Surgery of Trauma (AAST) scales. CT detection rates of organ injury and AAST grading with the two protocols were compared by McNemar test. Subjective analysis of image noise and artifacts and objective analysis of CT noise were performed by unpaired t test. RESULTS. Compared with the routine-dose protocol, the low-dose protocol enabled an mean dose reduction of 59.8%. The detection rates and diagnostic performance of AAST grading did not differ significantly between the two protocols (detection rate, p = 0.289; diagnostic performance, p > 0.999). Objective image noise was significantly less with the low-dose protocol than with the routine-dose protocol (p < 0.001). Subjective imaging artifacts were similar between the low-dose and routine-dose protocols (p = 0.539). CONCLUSION. Compared with routine-dose protocol with FBP, low-dose CT with ASIR-V was useful for assessing multiorgan abdominal injury without impairing image quality.

CT scan incidental findings in trauma patients: does it impact hospital length of stay?

Background

CT scans are heavily relied on for assessment of solid organ injuries complementing clinical examination. These CT scans could also reveal pathologies not related to trauma called incidental findings. We aimed to evaluate the frequency of these findings and their outcome on hospital services.

Methods

A retrospective chart review of prospectively collected data of the emergency department's trauma database from January 2005 to December 2011 to evaluate incidental findings on CT scans on trauma admissions. These incidental findings were divided into three classes: class 1-minor degenerative, non-degenerative, normal variants or congenital finding that does not require further investigation or workup; class 2-findings not requiring urgent intervention with scheduled outpatient follow-up and class 3-all findings that require urgent evaluation/further investigation during the same hospital admission. One-year follow-up was done to review hospital length of stay, trauma clinic follow-up and post-trauma surgery.

Results

Of 1000 charts reviewed, 957 were selected after 43 patients were excluded due to incomplete documentation. Of the 957 patients, 385 (40%) were found to have incidental findings. A total of 560 incidental findings were found on the CT scan reports with one-third of patients having multiple findings (144 patients, 37.4%). The largest number of incidental findings were in class 2. The incidental group had significantly longer length of stay after adjusted multivariate analysis (8.7±0.48 vs 6.7±0.55, p=0.005).

Conclusion

The incidental findings are commonly found during CT imaging in trauma centers and our rate was 40%. Appropriate documentation, communication and follow-up of those findings is necessary. A classification system for these findings practiced nationwide will aid in categorizing the urgency of continued follow-up. This also will help decrease the length of hospital stay and healthcare cost.

Level of evidence

Level 4.

Quarterly Reporting of Computed Tomography Ordering History Reduces the Use of Imaging in an Emergency Department

BACKGROUND

Computed tomography (CT) is a useful and necessary part of many emergency department (ED) assessments. However, the costs of imaging and the health risks associated with radiation exposure have sparked national efforts to reduce CT ordering in EDs.

STUDY OBJECTIVE

We analyzed CT ordering habits prior to and following implementation of a feedback tool at a community hospital.

METHODS

In this intervention study, we identified the CT-ordering habits of physicians and mid-level care providers (physician assistants and nurse practitioners) at baseline and after implementation of a system that sent quarterly feedback reports comparing their ordering habits with those of their peers. Variability in ordering and subgroup analyses by body region were included in these reports.

RESULTS

We examined the records of 104,454 patients seen between October 1, 2013 and December 31, 2014. There were 5552 or 21.0% of patients seen during the baseline period that underwent CT imaging. We observed an absolute reduction in imaging of 2.3% (95% confidence interval 1.7-2.8%) after implementation, avoiding approximately $400,000 in costs, 22 days of scanning time, and radiation exposure equivalent to 33,000 chest films annually. These changes occurred across physicians and mid-level providers, regardless of the number years of practice or board certification.

CONCLUSIONS

Implementation of a feedback mechanism reduced CT use by emergency medicine practitioners, with concomitant reductions in cost and radiation exposure. The change was similar across levels of medical care. Future studies will examine the effect of the feedback reporting system at other institutions in our hospital network.

Cumulative doses analysis in young trauma patients: a single-centre experience

Multidetector computed tomography (MDCT) represents the main source of radiation exposure in trauma patients. The radiation exposure of young patients is a matter of considerable medical concern due to possible long-term effects. Multiple MDCT studies have been observed in the young trauma population with an increase in radiation exposure. We have identified 249 young adult patients (178 men and 71 women; age range 14-40 years) who had received more than one MDCT study between June 2010 and June 2014. According to the International Commission on Radiological Protection publication, we have calculated the cumulative organ dose tissue-weighting factors by using CT-EXPO software(®). We have observed a mean cumulative dose of about 27 mSv (range from 3 to 297 mSv). The distribution analysis is characterised by low effective dose, below 20 mSv, in the majority of the patients. However, in 29 patients, the effective dose was found to be higher than 20 mSv. Dose distribution for the various organs analysed (breasts, ovaries, testicles, heart and eye lenses) shows an intense peak for lower doses, but in some cases high doses were recorded. Even though cumulative doses may have long-term effects, which are still under debate, high doses are observed in this specific group of young patients.