Computed tomography use in a large Italian region: trend analysis 2004-2014 of emergency and outpatient CT examinations in children and adults

Cumulative Dose from Recurrent CT Scans: Exploring the DNA Damage Response in Human Non-Transformed Cells

Recurrent computed tomography (CT) examination has become a common diagnostic procedure for several diseases and injuries. Though each singular CT scan exposes individuals at low doses of low linear energy transfer (LET) radiation, the cumulative dose received from recurrent CT scans poses an increasing concern for potential health risks. Here, we evaluated the biological effects of recurrent CT scans on the DNA damage response (DDR) in human fibroblasts and retinal pigment epithelial cells maintained in culture for five months and subjected to four CT scans, one every four weeks. DDR kinetics and eventual accumulation of persistent-radiation-induced foci (P-RIF) were assessed by combined immunofluorescence for γH2AX and 53BP1, i.e., γH2AX/53BP1 foci. We found that CT scan repetitions significantly increased both the number and size of γH2AX/53BP1 foci. In particular, after the third CT scan, we observed the appearance of giant foci that might result from the overlapping of individual small foci and that do not associate with irreversible growth arrest, as shown by DNA replication in the foci-carrying cells. Whether these giant foci represent coalescence of unrepaired DNA damage as reported following single exposition to high doses of high LET radiation is still unclear. However, morphologically, these giant foci resemble the recently described compartmentalization of damaged DNA that should facilitate the repair of DNA double-strand breaks but also increase the risk of chromosomal translocations. Overall, these results indicate that for a correct evaluation of the damage following recurrent CT examinations, it is necessary to consider the size and composition of the foci in addition to their number.

Influence of deep learning image reconstruction algorithm for reducing radiation dose and image noise compared to iterative reconstruction and filtered back projection for head and chest computed tomography examinations: a systematic review

Background

The most recent advances in Computed Tomography (CT) image reconstruction technology are Deep learning image reconstruction (DLIR) algorithms. Due to drawbacks in Iterative reconstruction (IR) techniques such as negative image texture and nonlinear spatial resolutions, DLIRs are gradually replacing them. However, the potential use of DLIR in Head and Chest CT has to be examined further. Hence, the purpose of the study is to review the influence of DLIR on Radiation dose (RD), Image noise (IN), and outcomes of the studies compared with IR and FBP in Head and Chest CT examinations.

Methods

We performed a detailed search in PubMed, Scopus, Web of Science, Cochrane Library, and Embase to find the articles reported using DLIR for Head and Chest CT examinations between 2017 to 2023. Data were retrieved from the short-listed studies using Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines.

Results

Out of 196 articles searched, 15 articles were included. A total of 1292 sample size was included. 14 articles were rated as high and 1 article as moderate quality. All studies compared DLIR to IR techniques. 5 studies compared DLIR with IR and FBP. The review showed that DLIR improved IQ, and reduced RD and IN for CT Head and Chest examinations.

Conclusions

DLIR algorithm have demonstrated a noted enhancement in IQ with reduced IN for CT Head and Chest examinations at lower dose compared with IR and FBP. DLIR showed potential for enhancing patient care by reducing radiation risks and increasing diagnostic accuracy.

Opportunistic Extraction of Quantitative CT Biomarkers: Turning the Incidental Into Prognostic Information

The past two decades have seen a significant increase in the use of CT, with a corresponding rise in the mean population radiation dose. This rise in CT use has caused improved diagnostic certainty in conditions that were not previously routinely evaluated using CT, such as headaches, back pain, and chest pain. Unused data, unrelated to the primary diagnosis, embedded within these scans have the potential to provide organ-specific measurements that can be used to prognosticate or risk-profile patients for a wide variety of conditions. The recent increased availability of computing power, expertise and software for automated segmentation and measurements, assisted by artificial intelligence, provides a conducive environment for the deployment of these analyses into routine use. Data gathering from CT has the potential to add value to examinations and help offset the public perception of harm from radiation exposure. We review the potential for the collection of these data and propose the incorporation of this strategy into routine clinical practice.

Knowledge and Perception of Radiation Risk From Computed Tomography Scans Among Patients Attending an Emergency Department

To evaluate the level of knowledge about radiation dose and possible risks related to computed tomography (CT) scans among patients visiting emergency departments (EDs), a survey was conducted over a two-month period. A total of 357 adult patients (44% men and 56% women) presenting for diagnostic imaging in the ED answered a survey consisting of 15 questions. The survey included questions about the participants' demographics and knowledge of radiation. Most of the respondents (58.5%) reported that the physician did not explain the potential risk of radiation before the procedure. In addition, more than half of the respondents (58.1%) expressed feeling anxious about the potential risk of radiation. Most respondents (84.9%) stated that the potential radiation risk did not affect their decision to proceed with the procedure. Overall, the findings highlight a lack of information about radiation and its potential risks provided to patients prior to the diagnostic procedure. Increasing awareness and understanding of the risks associated with these imaging modalities should be considered essential in modern communities. Efforts should be made to ensure that patients undergoing diagnostic imaging are aware of the radiation risks they may encounter.

Consumable Material Waste and Workflow Efficiency Comparison Between Multi-use Syringeless and Single-use Syringe-Based Injectors in Computed Tomography

RATIONALE AND OBJECTIVES

Syringeless power injectors obviate the need for reloading iodinated contrast media (ICM) and plastic consumable pistons between exams. This study evaluates the potential time and material waste (ICM, plastic, saline, and total) saved using a multi-use syringeless injector (MUSI) compared to a single-use syringe-based injector (SUSI).

MATERIALS AND METHODS

Two observers recorded technologist time spent using a SUSI and a MUSI over three clinical workdays. CT technologists (n = 15) were polled on their experience between the systems using a 5-point Likert scale survey. ICM, plastic, and saline waste data from each system were collected. A mathematical model was created to estimate total and categorical waste from each injector system over a 16-week period.

RESULTS

On average, CT technologists spent 40.5 seconds less per exam with MUSI compared to SUSI (p < .001). Technologists rated MUSI work efficiency, user-friendliness, and overall satisfaction (strongly or somewhat improved) higher relative to SUSI (p < .05). Iodine waste was 31.3 L and 0.0 L for SUSI and MUSI, respectively. Plastic waste was 467.7 kg and 71.9 kg for SUSI and MUSI, respectively. Saline waste was 43.3 L and 52.5 L for SUSI and MUSI, respectively. Total waste was 555.0 kg and 124.4 kg for SUSI and MUSI respectively.

CONCLUSION

Switching from SUSI to MUSI resulted in a 100%, 84.6%, and 77.6% reduction in ICM, plastic, and total waste. This system may fortify institutional endeavors toward green radiology initiatives. The potential time saved administering contrast using MUSI may improve CT technologist efficiency.

Individualized scan protocols for CT angiography: an animal study for contrast media or radiation dose optimization

BACKGROUND

We investigated about optimization of contrast media (CM) dose or radiation dose in thoracoabdominal computed tomography angiography (CTA) by automated tube voltage selection (ATVS) system configuration and CM protocol adaption.

METHODS

In six minipigs, CTA-optimized protocols were evaluated regarding objective (contrast-to-noise ratio, CNR) and subjective (6 criteria assessed by Likert scale) image quality. Scan parameters were automatically adapted by the ATVS system operating at 90-kV semi-mode and configured for standard, CM saving, or radiation dose saving (image task, quality settings). Injection protocols (dose, flow rate) were adapted manually. This approach was tested for normal and simulated obese conditions.

RESULTS

Radiation exposure (volume-weighted CT dose index) for normal (obese) conditions was 2.4 ± 0.7 (5.0 ± 0.7) mGy (standard), 4.3 ± 1.1 (9.0 ± 1.3) mGy (CM reduced), and 1.7 ± 0.5 (3.5 ± 0.5) mGy (radiation reduced). The respective CM doses for normal (obese) settings were 210 (240) mgI/kg, 155 (177) mgI/kg, and 252 (288) mgI/kg. No significant differences in CNR (normal; obese) were observed between standard (17.8 ± 3.0; 19.2 ± 4.0), CM-reduced (18.2 ± 3.3; 20.5 ± 4.9), and radiation-saving CTAs (16.0 ± 3.4; 18.4 ± 4.1). Subjective analysis showed similar values for optimized and standard CTAs. Only the parameter diagnostic acceptability was significantly lower for radiation-saving CTA compared to the standard CTA.

CONCLUSIONS

The CM dose (-26%) or radiation dose (-30%) for thoracoabdominal CTA can be reduced while maintaining objective and subjective image quality, demonstrating the feasibility of the personalization of CTA scan protocols.

KEY POINTS

• Computed tomography angiography protocols could be adapted to individual patient requirements using an automated tube voltage selection system combined with adjusted contrast media injection. • Using an adapted automated tube voltage selection system, a contrast media dose reduction (-26%) or radiation dose reduction (-30%) could be possible.

ICU patients with infectious complications after abdominopelvic surgery: Is thoracic CT in addition to abdominal CT helpful?

BACKGROUND

The aim of this study was to assess the usefulness of adding thoracic CT to abdominal CT in intensive care unit (ICU) patients with signs of infection after abdominopelvic surgery.

METHODS

143 thoracoabdominal CTs of ICU patients with signs of infection after abdominopelvic surgery were retrospectively reviewed for thoracic pathologies. It was determined if pathologic findings were visible only on thoracic CT above the diaphragmatic dome or also on abdominal CT up to the diaphragmatic dome. All thoracic pathologies visible only above the diaphragmatic dome were retrospectively analyzed by an ICU physician in terms of clinical relevance. Diagnostic and therapeutic efficacy of thoracic CT were assessed with regard to an infectious focus and to other pathologic findings.

RESULTS

297 pathologic thoracic findings were recorded. 26 of the 297 findings could only be detected on images obtained above the diaphragmatic dome (in 23 of 143 CTs). A change in patient management was initiated due to only one of the 26 supradiaphragmatic findings. Diagnostic efficacy of thoracic CT in addition to abdominal CT to identify an infectious focus was 3.5% (95%-CI: 0.5-6.5%) and therapeutic efficacy was 0.7% (95%-CI: 0-2.1%). With regard to all pathologic thoracic findings, diagnostic efficacy was 16.1% (95%-CI: 10.1-22.1%) and therapeutic efficacy remained at 0.7%.

CONCLUSIONS

Additional thoracic CT to detect an infectious focus in ICU patients after abdominopelvic surgery leads to identification of the focus in only 3.5% and to changes in patient management in only 0.7%. Other relevant findings are more common (16.1%), but very rarely affect patient management.

The impact of performance feedback reports on physician ordering behavior in the use of computed tomography pulmonary angiography (CTPA)

PURPOSE

The increased utilization, and potential overutilization, of computed tomography pulmonary angiography (CTPA) is a well-recognized issue within emergency departments (EDs). The objective of this study is to determine the impact of performance feedback reports on CTPA ordering behavior among ED physicians.

METHODS

We conducted a prospective study of the impact of individualized performance feedback reports on the ordering behavior of physicians working at two high-volume community EDs in Ontario, Canada. We generated individualized reports (or "Dashboards") for each ED physician containing detailed feedback and peer comparison for each physician's CTPA ordering. Our baseline pre-intervention period was January 1 to December 31, 2018, and our intervention period was January 1, 2019, to December 31, 2021. We tracked individual and group ordering behavior through the study period. Our primary outcomes are impact of feedback on (1) overall group ordering rate and (2) overall diagnostic yield. Secondary analysis was done to determine the impact of the intervention on those physicians with the highest CTPA utilization rate.

RESULTS

There was no statistically significant difference in the diagnostic yield of the included physicians in either of the years of the intervention period. There was a statically significant increase in the utilization rate for CTPA from 2018 to 2020 and 2021 from 5.9 to 7.9 and 11.4 CTPAs per 1000 ED visits respectively (p < 0.5).

CONCLUSION

Our study found no consistent significant impact of individualized feedback and peer comparison on physician ordering of CTPAs. This points to a potentially greater impact of environmental and institutional factors, as opposed to physician-targeted quality improvement measures, on physician ordering behavior.

CT Scans and Cancer Risks: A Systematic Review and Dose-response Meta-analysis

BACKGROUND

There is still uncertainty on whether ionizing radiation from CT scans can increase the risks of cancer. This study aimed to identify the association of cumulative ionizing radiation from CT scans with pertaining cancer risks in adults.

METHODS

Five databases were searched from their inception to November 15, 2020. Observational studies reporting cancer risks from CT scans in adults were included. The main outcome included quantified cancer risks as cancer case numbers in exposed/unexposed adult participants with unified converted measures to odds ratio (OR) for relative risk, hazard ratio. Global background radiation (2.4 mSv per year) was used as control for lifetime attribution risk (LAR), with the same period from incubation after exposure until survival to 100 years.

RESULTS

25 studies were included with a sum of 111,649,943 participants (mean age: 45.37 years, 83.4% women), comprising 2,049,943 actual participants from 6 studies with an average follow-up period as 30.1 years (range, 5 to 80 years); 109,600,000 participants from 19 studies using LAR. The cancer risks for adults following CT scans were inordinately increased (LAR adults, OR, 10.00 [95% CI, 5.87 to 17.05]; actual adults, OR, 1.17 [95%CI, 0.89 to 1.55]; combined, OR, 5.89 [95%CI, 3.46 to 10.35]). Moreover, cancer risks elevated with increase of radiation dose (OR, 33.31 [95% CI, 21.33 to 52.02]), and multiple CT scan sites (OR, 14.08 [95% CI, 6.60 to 30.05]). The risk of solid malignancy was higher than leukemia. Notably, there were no significant differences for age, gender, country, continent, study quality and studying time phrases.

CONCLUSIONS

Based on 111.6 million adult participants from 3 continents (Asia, Europe and America), this meta-analysis identifies an inordinately increase in cancer risks from CT scans for adults. Moreover, the cancer risks were positively correlated with radiation dose and CT sites. The meta-analysis highlights the awareness of potential cancer risks of CT scans as well as more reasonable methodology to quantify cancer risks in terms of life expectancy as 100 years for LAR.

PROSPERO TRIAL REGISTRATION NUMBER

CRD42019133487.

INVESTIGATION OF RADIATION RISKS BASED ON THE CLINICAL FINDINGS FROM HEAD CT SCANS IN TRAUMA

This study aimed to investigate the radiation risks in terms of effective dose and the cancer risk probability resulting from computed tomography (CT) scans of the head for traumatic patients and determine how often traumatic abnormalities occur. Data were collected retrospectively for 138 traumatic patients from the picture archiving and communication system, including exposure parameters and clinical findings. The mean values of the dose length product, CT dose index volume and effective dose for the CT head examinations were 787 ± 67.7 mGy•cm, 40.1 ± 1.33 mGy and 1.47 ± 0.12 mSv, respectively. Of the total cases of CT scans of the head, 57.2% (n = 79) exhibited positive findings. The cancer risk probability for the patients was 6.04 × 10-5 per procedure, with no statistically significant differences between positive and negative findings (p = 0.345). Taking into consideration the justification of the examination, the risk of missing positive findings and the radiation risks, the immediate benefit of head CT for trauma patients for guiding medical decisions outweighs the radiation risk that will probably manifest later.

Aortic calcification index predicts mortality and cardiovascular events in operatively treated patients with peripheral artery disease A prospective PUREASO cohort follow-up study

OBJECTIVE

Present study evaluates the association of aortic calcification to mortality and major adverse cardiovascular and leg events (MACE and MALE) in patients with peripheral artery disease (PAD). The risk for mortality and MACE and MALE events is considered in clinical decision making.

METHODS

This cohort found in 2012 - 2013 consists of 226 symptomatic PAD patients referred to Turku University Hospital for invasive treatment. Follow-up data about mortality and survival without MACEs and MALEs was collected up to 5 years from inclusion date and aortic calcification index (ACI) was measured from patients with available imaging studies (164 of 226). ACIs association with events and mortality was evaluated in Cox regression, Kaplan-Meier and Classification and regression tree analysis.

RESULTS

All-cause mortality at 1, 3 and 5 years was 13.7%, (31), 26.1% (59) and 46.9% (106), respectively. In multivariable Cox regression analysis ACI and ACI>43 were independent risk factors for all-cause mortality (HR 1.13 per 10 units 95%CI, 1.00-1.22 and HR 1.83, 95%CI, 1.01-3.32, respectively) and for MACE (HR 1.10 per 10 units, 95%CI, 1.00-1.22 and HR 3.14, 95%CI, 1.67-5.91, respectively), but not for MALES. Classification and regression tree analysis showed that ACI 43 best divides cohort in relation to mortality. Kaplan-Meier analyses showed that ACI>43 is associated with greater mortality and occurrence of MACEs compared to those who have ACI≤43 (log-rank p-value 0.005 and 0.0012, respectively).

CONCLUSION

Risk for mortality and MACEs is associated with high ACI. ACI can expose PAD patients' risk for further cardiovascular events and mortality.

Analysis of a monocentric computed tomography dosimetric database using a radiation dose index monitoring software: dose levels and alerts before and after the implementation of the adaptive statistical iterative reconstruction on CT images

OBJECTIVE

To analyze dosimetric data of a single center by a radiation dose index monitoring software evaluating quantitatively the dose reduction obtained with the implementation of the adaptive statistical iterative reconstruction (ASIR) on Computed Tomography in terms of both the value of the dose length product (DLP) and the alerts provided by the dose tool.

METHODS

Dosimetric quantities were acquired using Qaelum DOSE tool (QAELUM NV, Leuven-Heverlee, Belgium). Dose data pertaining to CT examinations were performed using a General Electric Healthcare CT tomography with 64 detectors. CT dose data were collected over 4 years (January 1, 2017 to December 31, 2020) and included CT dose length product (DLP). Moreover, all CT examinations that triggered a high radiation dose (twice the median for that study description), termed alerts on Dose tool, were retrieved for the analysis. Two radiologists retrospectively assessed CT examinations in consensus for the images quality and for the causes of the alerts issued. A Chi-square test was used to assess whether there were any statistically significant differences among categorical variable while a Kruskal Wallis test was considered to assess differences statistically significant for continuous variables.

RESULTS

Differences statistically significant were found for the DLP median values between the dosimetric data recorded on 2017-2018 versus 2019-2020. The differences were linked to the implementation of ASIR technique at the end of 2018 on the CT scanner. The highest percentage of alerts was reported in the CT study group "COMPLETE ABDOMEN + CHEST + HEAD" (range from 1.26% to 2.14%). A reduction year for year was relieved linked to the CT protocol optimization with a difference statistically significant. The highest percentage of alerts was linked to wrong study label/wrong study protocol selection with a range from 29 to 40%.

CONCLUSIONS

Automated methods of radiation dose data collection allowed for detailed radiation dose analysis according to protocol and equipment over time. The use of CT ASIR technique could determine considerable reduction in radiation dose.

Sarcopenia: how to measure, when and why

Sarcopenia indicates a loss of skeletal muscle mass, a condition that leads to a decline in physical performance. In 2018, the European Working Group on Sarcopenia in Older People met to update the original definition of sarcopenia: New scientific and clinical insights were introduced to emphasize the importance of muscle strength loss as a prime indicator of probable sarcopenia. In addition, the skeletal muscle is not only the organ related to mobility, but it is recognized as a secondary secretory organ too, with endocrine functions influencing several systems and preserving health. In this perspective, radiology could have a major role in early detection of sarcopenia and guarantee improvement in its treatment in clinical practice. We present here an update of clinical knowledge about sarcopenia and advantages and limitations of radiological evaluation of sarcopenia focusing on major body composition imaging modalities such as dual-energy X-ray absorptiometry, CT, and MRI. In addition, we discuss controversial such as the lack of consensus or standardization, different measurement methods, and diagnostic radiological cutoff points. Sarcopenia evaluation with radiological methods could enhance the role of radiologist in performing studies with relevant impact on medical and social outcome, placing radiology at the pinnacle of quality in evidence-based practice with high-level studies.

National Trends in Pediatric CT Scans in South Korea: A Nationwide Cohort Study

Purpose

This study evaluated the rates and annual trends of pediatric CT scans in South Korea using a nationwide population-based database.

Materials and Methods

Data regarding pediatric CT scan usage between 2012 and 2017 were retrieved from the health insurance review and assessment service. Data on the age, sex, diagnosis, and the anatomical area of involved patients were also extracted.

Results

A total of 576376 CT examinations were performed among 58527528 children aged below 18 years (9.8 scans/1000 children), and the number of CT examinations per 1000 children was noted to have increased by 23.2% from 9.0 in 2012 to 11.0 in 2017. Specifically, the number of CT examinations increased by 32.9% for the 6–12 years of age group (7.4/1000 to 9.8/1000) and by 34.0% for the 13–18 years of age group (11.4/1000 to 15.3/1000). Moreover, majority of the CT scans were limited to the head (39.1%), followed by the extremities (32.5%) and the abdomen (13.7%). Notably, the number of extremity CT scans increased by 83.6% (2.3/1000 to 4.2/1000), and its proportion as compared to other scans increased from 25.3% to 37.7%.

Conclusion

CT scans in the pediatric population increased continuously from 2012 to 2017 at an annual rate of 4.4%. Therefore, physicians should balance the benefits of CT with its potential harms from associated radiation exposure in pediatric patients.

CORRELATION BETWEEN ANTERIOR-POSTERIOR AND LATERAL DIMENSIONS WITH THE EFFECTIVE AND WATER-EQUIVALENT DIAMETERS IN AXIAL IMAGES FROM HEAD COMPUTED TOMOGRAPHY EXAMINATIONS

The study aims to correlate the effective diameter (Deff) and water-equivalent diameter (Dw) parameters with anterior-posterior (AP), lateral (LAT) and AP + LAT dimensions in order to estimate the patient dose in head CT examinations. Seventy-four patient datasets from head CT examinations were retrospectively collected. The patient's sizes were calculated from the middle slice using a software of IndoseCT. Dw and Deff were plotted as functions of AP, LAT and AP + LAT dimensions. The best trendline fit for LAT and AP functions was a second order polynomial, which resulted in R2 of 0.89 for Deff vs LAT, 0.88 for Dw vs LAT, 0.92 for Deff vs AP and 0.91 for Dw vs AP. A linear correlation was found for Deff vs AP + LAT, Dw vs AP + LAT and Dw vs Deff with R2 of 0.97, 0.96 and 0.98, respectively.

The effective and water-equivalent diameters as geometrical size functions for estimating CT dose in the thoracic, abdominal, and pelvic regions

Purpose: The aim of this work was to establish the relationships of patient size in terms of effective diameter (Deff) and water-equivalent diameter (Dw) with lateral (LAT) and anterior-posterior (AP) dimensions in order to predict the specific patient dose for thoracic, abdominal, and pelvic computed tomography (CT) examinations.

Methods: A total of 47 thoracic images, 79 abdominal images, and 50 pelvic images were analyzed in this study. The patient’s images were retrospectively collected from Dr. Kariadi and Kensaras Hospitals, Semarang, Indonesia. The slices measured were taken from the middle of the scan range. The calculations of patient sizes (LAT, AP, Deff, and Dw) were automatically performed by IndoseCT 20b software. Deff and Dw were plotted as functions of LAT, AP, and AP+LAT. In addition, Dw was plotted as a function of Deff.

Results: Strong correlations of Deff and Dw with LAT, AP, and AP+LAT were found. Stronger correlations were found in the Deff curves (R2 > 0.9) than in the Dw curves (R2 > 0.8). It was found that the average Deff was higher than the average Dw in the thoracic region, the average values were similar in the abdominal and pelvic regions.

Conclusion: The current study extended the study of the relationships between Deff and Dw and the basic geometric diameter LAT, AP, and AP+LAT beyond those previously reported by AAPM. We evaluated the relationships for three regions, i.e. thoracic, abdominal, and pelvic regions. Based on our findings, it was possible to estimate Deff and Dw from only the LAT or AP dimension.

Workload of diagnostic radiologists in the foreseeable future based on recent scientific advances: growth expectations and role of artificial intelligence

Objective

To determine the anticipated contribution of recently published medical imaging literature, including artificial intelligence (AI), on the workload of diagnostic radiologists.

Methods

This study included a random sample of 440 medical imaging studies published in 2019. The direct contribution of each study to patient care and its effect on the workload of diagnostic radiologists (i.e., number of examinations performed per time unit) was assessed. Separate analyses were done for an academic tertiary care center and a non-academic general teaching hospital.

Results

In the academic tertiary care center setting, 65.0% (286/440) of studies could directly contribute to patient care, of which 48.3% (138/286) would increase workload, 46.2% (132/286) would not change workload, 4.5% (13/286) would decrease workload, and 1.0% (3/286) had an unclear effect on workload. In the non-academic general teaching hospital setting, 63.0% (277/240) of studies could directly contribute to patient care, of which 48.7% (135/277) would increase workload, 46.2% (128/277) would not change workload, 4.3% (12/277) would decrease workload, and 0.7% (2/277) had an unclear effect on workload. Studies with AI as primary research area were significantly associated with an increased workload (p < 0.001), with an odds ratio (OR) of 10.64 (95% confidence interval (CI) 3.25–34.80) in the academic tertiary care center setting and an OR of 10.45 (95% CI 3.19–34.21) in the non-academic general teaching hospital setting.

Conclusions

Recently published medical imaging studies often add value to radiological patient care. However, they likely increase the overall workload of diagnostic radiologists, and this particularly applies to AI studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-021-01031-4.

The reliability of radiation dose display of a computed tomography scanner

•

There is variation in the difference between the radiation dose reported by the CT scanner and actual measured dose.

•

This variation is substantial and may differ from zero.

•

To achieve more precise radiation dose data, especially in comparing studies, the average difference should be determined.

•

A correction factor for radiation dose should be utilized for every scanner used in studies.

Background

Internationally, the typical allowed difference between the measured radiation dose and dose reported by a computed tomography (CT) scanner is ±20 %. The objective is to describe a method in order to analyse this difference in a CT scanner in the Emergency Department of Kanta-Häme Central Hospital, and to calculate a correction factor for more comparable radiation dose values in further studies.

Methods

Ten intra-day radiation dose measurements were performed with undisturbed setting. Measurement reports on differences between measured and displayed dose were gathered from the vendor maintenance and supervising authority over a 12-year period. Additionally, two in-house measurements were made. A total of 18 datapoints were collected, with some differences in measurement settings. Data were also analysed against imaging parameters, ambient air pressure and time to identify trends or associations in the variation of the discrepancy.

Results

Measured doses were generally lower than displayed doses. Differences between displayed and measured doses varied between −3.46 and −0.10 %, with a mean of −1.26 % in the intra-day measurements, and between +4.65 and −17.3 %, with a mean of −7.53 % in the long-term data. There were no trends nor connections in the variations.

Conclusion

Since the acceptable difference between the radiation dose display and the measured dose is relevant, the average difference for every CT scanner should be determined before radiation dose studies, especially when comparing multiple scanners.

Towards a benchmark of abdominal CT use during duty shifts: 15-year sample from the Netherlands

Purpose

To investigate temporal changes in the utilization and patient impact of abdominal CT during duty shifts in the past 15 years.

Methods

This study included a random sample of 1761 abdominal CT scans that were made during evening and night duty shifts in a tertiary care center between 2005 and 2019.

Results

The number of CT scans significantly increased (almost threefold) between 2005 and 2019 (Mann–Kendall tau of 0.829, P < 0.001). The proportion of negative CT scans (i.e., the absence of findings related to the reason that the CT scan was made and no disease deterioration or other new and clinically relevant findings compared to a previous imaging examination when available) was 40.0% (700/1749) in the entire 15-year study frame and did not significantly change over time (Mann–Kendall tau of − 0.219, P = 0.276). The overall frequency of same-day hospital discharge after negative CT was 20.6% (150/729) in the past 15 years and showed a significant increase over time (Mann–Kendall tau of 0.505, P = 0.010). The overall proportion of CT scans with incidental findings was 3.4% (60/1761) and remained statistically stable over the past 15 years (Mann–Kendall tau of − 0.057, P = 0.804).

Conclusion

Over the past 15 years, the number of CT scans and the frequency of same-day hospital discharge after negative CT have increased, while the proportions of negative CT scans and incidental findings have remained stable in our tertiary care center. The data from this study can be used for interinstitutional benchmarking to define, monitor, and improve the appropriateness of imaging utilization.

Medical knowledge and clinical productivity: independently correlated metrics during radiology residency

Objective

To determine the association between medical knowledge relevant to radiology practice (as measured by the Dutch radiology progress test [DRPT]) and clinical productivity during radiology residency.

Methods

This study analyzed the results of 6 DRPTs and time period–matched clinical production points of radiology residents affiliated to a tertiary care academic medical center between 2013 and 2016. The Spearman correlation analysis was performed to determine the association between DRPT percentile scores and average daily clinical production points. Linear regression analyses were performed to determine the association of DRPT percentile scores with average daily clinical production points, adjusted for age and gender of the radiology resident, and postgraduate year.

Results

Eighty-four DRPTs with time period–matched clinical production points were included. These 84 DRPTs were made by 29 radiology residents (18 males and 11 females) with a median age of 31 years (range: 26–38 years). The Spearman correlation coefficient between DRPT percentile scores and average daily clinical production points was 0.550 (95% confidence interval: 0.381–0.694) (p < 0.001), indicating a significant moderate positive association. On multivariate analysis, average daily clinical production points (β coefficient of 0.035, p = 0.003), female gender of the radiology resident (β coefficient of 12.690, p = 0.001), and postgraduate year (β coefficient of 10.179, p < 0.001) were significantly associated with DRPT percentile scores. These three independent variables achieved an adjusted R² of 0.527.

Conclusion

Clinical productivity is independently associated with medical knowledge relevant to radiology practice during radiology residency. These findings indicate that clinical productivity of a resident could be a potentially relevant metric in a radiology training program.

Key Points

• There is a significant moderate correlation between medical knowledge relevant to radiology practice and clinical productivity during radiology residency.

• Medical knowledge relevant to radiology practice remains independently associated with clinical productivity during radiology residency after adjustment for postgraduate year and gender.

• Clinical productivity of a resident may be regarded as a potentially relevant metric in a radiology training program.

Impact of the COVID-19 pandemic on emergency department CT for suspected diverticulitis

PURPOSE

This study examined the impact of the COVID-19 pandemic on emergency department CT use for acute nontraumatic abdominal pain, to better understand why imaging volume so drastically decreased during the COVID-19 pandemic.

METHODS

This was a retrospective review of emergency imaging volumes from January 5 to May 30, 2020. Weekly volume data were collected for total imaging studies, abdominopelvic CT, and abdominopelvic CTs positive for common causes of acute nontraumatic abdominal pain. Two emergency radiology attendings scored all diverticulitis cases independently, and weekly volume data for uncomplicated and complicated diverticulitis cases was also collected. Volume data prior to and during the COVID-19 pandemic was compared, using 2019 volumes as a control.

RESULTS

During the COVID-19 pandemic, overall emergency imaging volume decreased 30% compared to 2019 (p = 0.002). While the number of emergency abdominopelvic CTs positive for appendicitis and small bowel obstruction did not significantly change during the COVID-19 pandemic, the number of cases of diverticulitis decreased significantly compared to 2019 (p = 0.001). This reduction can be specifically attributed to decreased uncomplicated diverticulitis cases, as the number of uncomplicated diverticulitis cases dropped significantly (p = 0.002) while there was no significant difference in the number of complicated diverticulitis cases (p = 0.09).

CONCLUSIONS

Reduced emergency abdominopelvic CT volume during the COVID-19 pandemic can partially be explained by decreased imaging of lower acuity patients. This data may help formulate future strategies for imaging resource utilization with an improved understanding of the relationship between perceived imaging risk and symptom acuity.

Assessing and coping with the financial burden of computed tomography utilization in Limbe, Cameroon: a sequential explanatory mixed-methods study

BACKGROUND

There has been a significant increase in computed tomography (CT) utilization over the past two decades with the major challenges being a high exposure to ionizing radiation and rising cost. In this study we assess the risk of financial hardship after CT utilization and elaborate on how users adapt and cope in a sub-Saharan context with user fee for services and no national health insurance policy.

METHODS

We carried out a sequential explanatory mixed methods study with a quantitative hospital-based survey of CT users followed by in-depth interviews of some purposively selected participants who reported risk of financial hardship after CT utilization. Data was summarized using frequencies, percentages and 95% confidence intervals. Logistic regression was used in multivariable analysis to determine predictors of risk of financial hardship. Identified themes from in-depth interviews were categorized. Quantitative and qualitative findings were integrated.

RESULTS

A total of 372 participants were surveyed with a male to female sex ratio of 1:1.2. The mean age (standard deviation) was 52(17) years. CT scans of the head and facial bones accounted for 63% (95%CI: 59-68%) and the top three indications were suspected stroke (27% [95%CI: 22-32%]), trauma (14% [95%CI: 10-18%]) and persistent headaches (14% [95%CI: 10-18%]). Seventy-two percent (95%CI: 67-76%) of the respondents reported being at risk of financial hardship after CT utilization and predictors in the multivariable analysis were a low socioeconomic status (aOR: 0.19 [95%CI: 0.10-0.38]; p < 0.001), being unemployed or retired (aOR: 11.75 [95%CI: 2.59-53.18]; p = 0.001) and not having any form of health insurance (aOR: 3.59 [95%CI: 1.31-9.85]; p = 0.013). Coping strategies included getting financial support from family and friends, borrowing money and obtaining discounts from the hospital administration and staff.

CONCLUSION

No health insurance ownership, being unemployed or retired and a low socioeconomic status are associated with financial hardship after CT utilization. Diverse coping strategies are utilized to lessen the financial burden, some with negative consequences. Minimizing out-of-pocket payments and/or the direct cost of CT can reduce this financial burden and improve CT access.

Patient organ and effective dose estimation in CT: comparison of four software applications

Background

Radiation dose in computed tomography (CT) has become a topic of high interest due to the increasing numbers of CT examinations performed worldwide. Hence, dose tracking and organ dose calculation software are increasingly used. We evaluated the organ dose variability associated with the use of different software applications or calculation methods.

Methods

We tested four commercial software applications on CT protocols actually in use in our hospital: CT-Expo, NCICT, NCICTX, and Virtual Dose. We compared dose coefficients, estimated organ doses and effective doses obtained by the four software applications by varying exposure parameters. Our results were also compared with estimates reported by the software authors.

Results

All four software applications showed dependence on tube voltage and volume CT dose index, while only CT-Expo was also dependent on other exposure parameters, in particular scanner model and pitch caused a variability till 50%. We found a disagreement between our results and those reported by the software authors (up to 600%), mainly due to a different extent of examined body regions. The relative range of the comparison of the four software applications was within 35% for most organs inside the scan region, but increased over the 100% for organs partially irradiated and outside the scan region. For effective doses, this variability was less evident (ranging from 9 to 36%).

Conclusions

The two main sources of organ dose variability were the software application used and the scan region set. Dose estimate must be related to the process used for its calculation.

Exposure to Tomographic Scans and Cancer Risks

BACKGROUND

Worldwide use of computed tomography (CT) scans has increased. However, the ionizing radiation from CT scans may increase the risk of cancer. This study examined the association between medical radiation from CT scans and the risk of thyroid cancer, lymphoma, and non-Hodgkin lymphoma (NHL) in adults.

METHODS

We conducted a nested case-control study in a cohort constructed from a population-based universal health insurance dataset in Taiwan in 2000-2013. In total, 22 853 thyroid cancer, 13 040 leukemia, and 20 157 NHL cases with their matched controls were included. Median follow-up times were 9.29-9.90 years for the three case-control groups. Medical radiation from CT scans was identified through physician order codes in medical insurance data from the index date to 3 years before a cancer diagnosis. Conditional logistic regression modeling was used for the overall and subsets of the population defined by sex and age groups to estimate the odds ratio (OR) and 95% confidence interval (CI) of the cancer risk associated with medical radiation.

RESULTS

Exposure to medical radiation from CT scans was associated with elevated risk of thyroid cancer (OR = 2.55, 95% CI = 2.36 to 2.75) and leukemia (OR = 1.55, 95% CI = 1.42 to 1.68). The elevated risk of thyroid cancer and leukemia in association with medical CT was stronger in women than in men. No statistically significant association between the risk of cancer and CT scans was observed in overall patients with NHL (OR = 1.05, 95% CI = 0.98 to 1.12); however, increased risks were found in patients aged 45 years or younger. A clear dose-response relationship was observed in patients 45 years or younger for all three cancers.

CONCLUSIONS

CT scans may be associated with an increased risk of thyroid cancer and leukemia in adults and in those diagnosed with NHL at a younger age.

Targeted radiation energy modulation using Saba shielding reduces breast dose without degrading image quality during thoracic CT examinations

OBJECTIVE

Breasts dose during thoracic computed tomography examinations is a serious challenge and practical dose reduction strategies is needed. The bismuth shielding is an available method for dose reduction; however, its use is on debate due to degrading effects on image quality. The aim of this study is to explore and evaluate the efficiency of a new composition of the X-ray absorbing material to achieve a shield with a lower impact on image quality.

MATERIALS AND METHODS

Different shields were manufactured with combinations of various weight percentage of copper and bismuth. Dose reduction ratio and image quality were evaluated in phantom studies. A controlled trial with 20 female participants was conducted for image quality assessment. The shield with a lower impact on image quality, named Saba shielding, was used in the clinical trial.

RESULTS

Shielding by one (1 T) and three thickness (3 T) of the constructed shields reduced the mean entrance skin dose of breasts about 52% and 73%, respectively. The shield with a composition of 90% Cu and 10% Bi (Saba shielding) had the lowest while the shield with 100% bismuth had the highest degrading effect on image quality. The Saba shielding could provide 21% higher dose reduction than the Bi shielding at the equivalent image quality. The 1 T Saba shielding did not cause artifacts in the reconstructed images.

CONCLUSION

The Saba shielding is flexible, cheap and user-friendly for shielding breasts in thoracic CT examinations while do not have the degrading effect of the Bi shielding on image quality.

Analysis of a multicentre cloud-based CT dosimetric database: preliminary results

BACKGROUND

To manage and analyse dosimetric data provided by computed tomography (CT) scanners from four Italian hospitals.

METHODS

A radiation dose index monitoring (RDIM) software was used to collect anonymised exams stored in a cloud server. Since hospitals use different names for the same procedure, digital imaging and communications in medicine (DICOM) tags more appropriate to describe exams were selected and associated to study common names (SCNs) from a radiology playbook according to scan region and use of contrast media. Retrospective analysis was carried out to describe population and to evaluate dosimetric indexes and inaccuracies associated with SCNs.

RESULTS

More than 400 procedures were clustered into 95 SCNs, but 78% of exams on adults were described with only 10 SCNs. Median values of dose-length product (DLP) and volumetric CT dose index (CTDI_vol) for three analysed SCNs were in agreement with those previously published. The percentage of inaccuracies does not heavily affect the dosimetric analysis on the whole cloud, since variations in median values reached at most 8%.

CONCLUSIONS

Implementation of a cloud-based RDIM software and related issues were described, showing the strength of the chosen playbook-based clustering and its usefulness for homogeneous data analysis. This approach may allow for optimisation actions, accurate assessment of the risk associated with radiation exposure, comparison of different facilities, and, last but not least, collection of information for the implementation of the 2013/59 Euratom Directive.