Driving healthcare forward: The potential of mobile MRI and CT units in streamlining radiological services in Saudi Arabia - A narrative review

BACKGROUND AND PURPOSE

This narrative review focuses on the role of mobile MRI and CT units in addressing the challenges of healthcare accessibility and patient wait times in Saudi Arabia. It underscores the growing demand for diagnostic imaging amid infrastructural and geographical barriers, emphasizing mobile units as innovative solutions for enhancing radiological services across diverse Saudi landscapes. The purpose of this study is to assess how these mobile technologies can mitigate service delays, improve patient outcomes, and support healthcare delivery in remote or underserved areas, reflecting on global trends towards more dynamic, patient-centered healthcare models.

METHODS

This review utilizes an expanded database search and refined keywords to ensure comprehensive literature coverage. The study focused on peer-review articles and grey literatures that directly examined the impact of these mobile units on healthcare accessibility, wait times, and service delivery. A thematic analysis identified significant contributions to accessibility improvements, emergency responses, and rural healthcare, highlighting areas for further research and policy development.

DISCUSSION

Mobile units have advanced technical specifications with high-field magnets and multi-slice CT scanners on par with fixed facilities. They prioritize patient comfort and safety with examination areas, control rooms, and waiting areas. Telemedicine capabilities allow real-time image transmission to specialists. Strategic deployment can address workforce shortages by distributing services equitably. Mobile units represent cost-effective solutions to expand healthcare access without fixed infrastructure.

CONCLUSION

Integration of mobile MRI and CT units in Saudi Arabia can transform access to diagnostic imaging by decentralizing services and directly reaching patients, including rural areas. Evidence shows mobile units reduce diagnostic delays and optimize resource use. Despite challenges, strategic investments and collaborations can overcome obstacles to make radiological services more equitable, flexible and patient-focused in Saudi Arabia.

Prospective dose monitoring using a manual dose management system: experience in brain computed tomography from a tertiary hospital in Nigeria

A manual radiation dose management system was developed to track the radiation dose and scan parameters of patients for brain computed tomography (CT). Radiation dose in volume computed tomography dose index (CTDIvol) and dose length product (DLP) were monitored to identify procedures that may require optimisation using notification values. The data were analysed and compared with national and international diagnostic reference levels (DRLs). A total of 596 brain CTs were monitored and grouped as <1: 36, 1-<5: 38, 5-<10: 25, 10-<15: 31 and adult: 466. The CTDIvol notification value identified the following number of examinations having high CTDIvol in <1 y: 1, 1-<5: 1, 5-<10: 0, 10-<15: 0 and adult (>15): 11. Furthermore, the DLP notification values identified the following examinations with high DLP in <1 y: 1, 1-<5:1, 5-<10:1, 10-<15: 1 and adults (>15): 18. The established local paediatric DLP DRLs were 2-3 times higher than the international paediatric DLP DRLs. This calls for a total protocol review and optimisation considering the local CT practices for paediatric imaging.

Green radiology: How to develop sustainable radiology

The phenomenon of global warming due to the increased emission of greenhouse gases makes it necessary to raise public awareness about the importance of promoting sustainable practices. The field of radiology is not an exception, as it consumes a large amount of energy and resources to operate equipment and generate images. Green radiology is a sustainable, innovative, and responsible approach in radiology practice that focuses on minimizing the negative environmental effects of the technologies and procedures used in radiology. Its primary goal is to reduce the carbon, water and ecological footprint in our services based on four strategic pillars: decreasing energy, water, and helium usage; properly recycling and/or disposing of waste and residues (including contrast media); minimizing the environmental impact of ionizing radiation; and promoting eco-friendly radiology practices.

Technical specifications of dose management systems: An international atomic energy agency survey

PURPOSE

Dose management systems (DMS) have been introduced in radiological services to facilitate patient radiation dose management and optimization in medical imaging. The purpose of this study was to gather as much information as possible on the technical characteristics of DMS currently available, regarding features that may be considered essential for simply ensuring regulatory compliance or desirable to fully utilize the potential role of DMS in optimization of many aspects of radiological examinations.

METHODS

A technical survey was carried out and all DMS developers currently available (both commercial and open source) were contacted and were asked to participate. An extensive questionnaire was prepared and uploaded in the IAEA International Research Integration System (IRIS) online platform which was used for data collection process. Most of the questions (93%) required a "Yes/No" answer, to facilitate an objective analysis of the survey results. Some free text questions and comments' slots were also included, to allow participants to give additional information and clarifications where necessary. Depending on the answer, they were considered either as "Yes" or "No."

RESULTS

Given the way that the questions were posed, every positive response indicated that a feature was offered. Thus, the percentage of positive responses was used as a measure of adherence. The percentages of positive answers per section (and sub-section) are presented in graphs and limitations of this type of analysis are discussed in detail.

CONCLUSIONS

The results of this survey clearly exhibit that large differences exist between the various DMS developers. Consequently, potential end users of a DMS should carefully determine which of the features available are essential for their needs, prioritize desirable features, but also consider their infrastructure, the level of support required and the budget available before selecting a DMS.

Establishment of diagnostic reference levels in computed tomography in two large hospitals in Oman

This study aimed to estimate diagnostic reference levels (DRLs) for the most frequent computed tomography (CT) imaging examinations to monitor and better control radiation doses delivered to patients. Seven CT imaging examinations: Head, Chest, Chest High Resolution (CHR), Abdomen Pelvis (AP), Chest Abdomen Pelvis (CAP), Kidneys Ureters Bladder (KUB) and Cardiac, were considered. CT dosimetric quantities and patient demographics were collected from data storage systems. Local typical values for DRLs were calculated for CTDIvol (mGy), dose length product (DLP) (mGy·cm) and effective doses (mSv) were estimated for each examination. The calculated DRLs were given as (median CTDIvol (mGy):median DLP (mGy·cm)): Head: 39:657; Chest: 13:451; CHR: 6:228; AP: 12:578; CAP: 20:807; KUB: 7:315, and Cardiac: 2:31. Estimated effective doses for Head, Chest, CHR, AP, CAP, KUB and Cardiac were 1.3, 12.7, 6.3, 12.5, 18.1, 5.8 and 0.8 mSv, respectively. The estimated DRLs will act as guidance doses to prevent systematic excess of patient doses.

[Explaining radiation dose exposure : The role of the banana equivalent dose compared to the effective dose in patient communication]

BACKGROUND AND OBJECTIVES

Communicating the amount and effects of ionizing radiation to patients prior to an examination using x‑rays is associated with challenges: first, calculating the expected dose prior to the examination and, second, quantifying and illustrating cancer risks. Analogies, such as comparing radiation exposure to accident risks, have limitations and may evoke unease. This study explores and compares two new approaches to discuss radiation exposure from common clinical examinations with patients: effective dose and exposure based on radioactive potassium-40 intake from the ingestion of bananas, the banana equivalent dose (BED).

MATERIALS AND METHODS

The effective doses of the diagnostic reference levels (DRL) for computed tomography (CT) and X-ray examinations in adults were calculated using mean conversion factors for specific anatomic body regions. For the BED calculation of the diagnostic reference levels, the radiation dose from a conventional banana ingested over 50 years per becquerel was calculated. The outcomes were juxtaposed against an equivalent number of bananas and its respective radiation doses.

RESULTS

The calculated doses, namely effective dose and BED, of the German DRL can serve as a reliable metric to discuss radiation exposure from medical imaging with patients prior to an examination.

CONCLUSION

This is the first study to calculate the effective doses of the current DRL and to compare these with the pseudoscientific unit BED. While the BED serves as an interesting illustration to metaphorize radiation exposure, it is recommended to use the calculated effective dose of the DRL as the basis for educational consultations with patients.

Virtual Non-Contrast Spectral CT in Renal Masses: Is It Time to Discard Conventional Unenhanced Phase?

Dual-layer Dual-Energy CT (dl-DECT) allows one to create virtual non-contrast (VNC) reconstructions from contrast-enhanced CT scans, with a consequent decrease of the radiation dose. This study aims to assess the reliability of VNC for the diagnostic evaluation of renal masses in comparison with true non-contrast (TNC) images. The study cohort included 100 renal masses in 40 patients who underwent dl-DECT between June and December 2021. Attenuation values and standard deviations were assessed through the drawing of regions of interest on TNC and VNC images reconstructed from corticomedullary and nephrographic phases. A Wilcoxon signed-rank test was performed in order to assess equivalence of data and Spearman's Rho correlation coefficient to evaluate correlations between each parameter. The diagnostic accuracy of VNC was estimated through the performance of receiver operating characteristic (ROC) curve analysis. Differences between attenuation values were, respectively, 74%, 18%, 5% and 3% (TNC-VNC_cort), and 74%, 15%, 9% and 2% (TNC-VNC_neph). The Wilcoxon signed-rank test demonstrated the equivalence of attenuation values between the TNC and VNC images. The diagnostic performance of VNC images in the depiction of kidney simple cysts remains high compared to TNC (VNC_cort-AUC: 0.896; VNC_neph-AUC: 0.901, TNC-AUC: 0.903). In conclusion, quantitative analysis of attenuation values showed a strong agreement between VNC and TNC images in the evaluation of renal masses.

Radiology's Ionising Radiation Paradox: Weighing the Indispensable Against the Detrimental in Medical Imaging

Ionising radiation stands as an indispensable protagonist in the narrative of medical imaging, underpinning diagnostic evaluations and therapeutic interventions across an array of medical conditions. However, this protagonist poses a paradox - its inestimable service to medicine coexists with an undercurrent of potential health risks, primarily DNA damage and subsequent oncogenesis. The narrative of this comprehensive review unfurls around this intricate enigma, delicately balancing the indispensable diagnostic utility against the non-negotiable commitment to patient safety. In this critical discourse, the intricacies of ionising radiation are dissected, illuminating not only its sources but also the associated biological and health hazards. The exploration delves into the labyrinth of strategies currently deployed to minimise exposure and safeguard patients. By casting light on the scientific nuances of X-rays, computed tomography (CT), and nuclear medicine, it traverses the complex terrain of radiation use in radiology, to promote safer medical imaging practices, and to facilitate an ongoing dialogue about diagnostic necessity and risk. Through a rigorous examination, the pivotal relationship between radiation dose and dose response is elucidated, unravelling the mechanisms of radiation injury and distinguishing between deterministic and stochastic effects. Moreover, protection strategies are illuminated, demystifying concepts such as justification, optimisation, the As Low As Reasonably Achievable (ALARA) principle, dose and diagnostic reference levels, along with administrative and regulatory approaches. With an eye on the horizon, promising avenues of future research are discussed. These encompass low-radiation imaging techniques, long-term risk assessment in large patient cohorts, and the transformative potential of artificial intelligence in dose optimisation. This exploration of the nuanced complexities of radiation use in radiology aims to foster a collaborative impetus towards safer medical imaging practices. It underscores the need for an ongoing dialogue around diagnostic necessity and risk, thereby advocating for a continual reassessment in the narrative of medical imaging.

Royal Decree 601/2019 on justification and optimization: Practical aspects

The Royal Decree 601/2019 of 18th October is the result of the partial transposition into the Spanish legal system of the Euratom Directive 59/2013. This Royal Decree includes the mandates of the Directive related to the need to justify and optimize medical exposure, including that of asymptomatic people, proposal of stricter requirements regarding the information that must be provided to the patient, registration and notification of the doses of medical-radiological procedures, use of reference levels for diagnosis and the availability of dose-indicating devices. The article reviews the most relevant aspects and novelties related to the principles of justification, optimization, dose control and the obligations derived from the right to information and consent. This Royal Decree considers essential for radiologists to develop a high level of competence and a new list of responsibilities and functions, which are detailed and analysed in this article.

Radiation dose management system in computed tomography procedures: a systematic review

A systematic literature review was carried out to explore articles that reported the use of radiation dose management systems (RDMSs) in computed tomography (CT). The preferred reporting items for systematic review and meta-analysis flow chart were used to screen articles in PubMed, EBSCOhost, Web of Science, SCOPUS and Cochrane Library. A total of 1041 articles were retrieved and screened. After evaluation against criteria, 38 articles were selected and synthesised narratively. The results revealed that several RDMSs have been used in CT. The review also indicated that the use of RDMSs has promoted the implementation of diagnostic reference levels for dose optimisation. A RDMS, such as DoseWatch, is associated with compatibility challenges and failure in data transmission, while manual RDMSs are cumbersome and prone to data entry errors. Thus, a robust automated RDMS that is compatible with the different CT systems would provide efficient CT dose management.

Diagnostic reference level quantities for adult chest and abdomen-pelvis CT examinations: correlation with organ doses

OBJECTIVES

To evaluate correlations between DRL quantities (DRLq) stratified into patient size groups for non-contrast chest and abdomen-pelvis CT examinations in adult patients and the corresponding organ doses.

METHODS

This study presents correlations between DRLq  (CTDI_vol, DLP and SSDE) stratified into patient size ranges and corresponding organ doses shared in four groups: inside, peripheral, distributed and outside. The demographic, technical and dosimetric parameters were used to identify the influence of these quantities in organ doses. A robust statistical method was implemented in order to establish these correlations and its statistical significance.

RESULTS

Median values of the grouped organ doses are presented according to the effective diameter ranges. Organ doses in the regions inside the imaged area are higher than the organ doses in peripheral, distributed and outside regions, excepted to the peripheral doses associated with chest examinations. Different levels of statistical significance between organ doses and the DRLq were presented.

CONCLUSIONS

Correlations between DRLq and target-organ doses associated with clinical practice can support guidance's to the establishment of optimization criteria. SSDE demonstrated to be significant in the evaluation of organ doses is also highlighted. The proposed model allows the design of optimization actions with specific risk-reduction results.

How to establish and use local diagnostic reference levels: an ESR EuroSafe Imaging expert statement

Abstract

Although the Diagnostic Reference Levels (DRLs) have been shown to be an important tool for optimising patient radiation protection, there are still difficulties related to the methodology that should be used to establish and use local DRL values. This statement represents the current view of the EuroSafe Imaging ‘Clinical DRLs’ working group formed with the purpose to produce scientific and educational material on DRLs and promote the concept of local DRLs. Guidelines on how to establish and how to use local DRLs presented herein can be implemented using a multidisciplinary team approach. Local DRLs are easy to determine and implement and they reflect local equipment performance and local clinical needs. They can be updated more frequently than the national DRLs, especially if a dose management system is available. To establish local DRLs, a practical approach could be to collect a reasonable set, i.e., at least 20–30 procedures, of data for well-defined clinical indications and calculate the 3rd quartile values. The median values of the distribution can be set to define the ‘typical values’. The International Commission of Radiological Protection (ICRP) suggests setting ‘typical values’ for newer technologies that enable decreased amounts of radiation exposure for a similar level of image quality. Local DRLs should be similar or lower to the national DRLs. They could be higher only if the clinical benefits for some medical indications are fully explained and reported. Local DRLs may be used as a quality benchmark to track outliers and can be also used as alert values.

Key points

Guidelines on how to establish and use local DRLs are presented.

Local DRLs are easy to determine and implement and can be updated frequently

Additionally, local DRLs can be used to track outliers.

Evaluating Effective Dose: A Comparison of Methods Based on Organ Dose Calculations versus Dose-Length Product and Monte Carlo Simulation

Computed tomography (CT) has had a massive impact on diagnostic radiology over the past few decades. Serious concerns exist because of the increase in the effective radiation dose associated with CT scans, which could pose significant health risks. In CT, the effective dose can be estimated by Monte Carlo simulations. The aim of the study was to estimate and compare the effective doses for CT from organ dose-based calculations using the tissue weighting factors of the International Commission on Radiological Protection publications (ICRP 60, 103), Monte Carlo CT-Expo v2.6, and dose-length product (DLP)-based estimates. For 165 CT scans, the effective doses (Ed) of the most common routine radiological investigations were assessed. There were 112 male patients (68%) and 53 female patients (32%). When compared to organ dose-based estimates, the DLP-based estimates of the effective dose produced by applying ICRP 60 coefficients were less than 55–57% (head) and more than 18.1% (chest) and 20% (abdomen). The ICRP 103 values of the Ed were less than 79% (head) and more than 17% (chest), and they changed randomly with the tissue weighting factors for the abdomen. For Monte Carlo CT-Expo, the Ed values were lower by 54% (head), 6% (abdomen), and more than 2% (chest) compared to organ dose-based estimates. Effective doses calculated using the tissue-weighting factors of ICRP 103 values comparable to ICRP 60 differ greatly by an average of 2.3, 2.9, and 4.5 mSv for the head, chest, and abdomen, respectively. In conclusion, all estimates of Ed are subject to the biases inflicted by the assumptions in the methods used; therefore, no significant agreement should be expected. The reason for evaluating ICRP 60 is to make a point that ICRP’s update is indeed more accurate. The variability associated with the use of various methodologies to estimate and compare the effective dose Ed in CT scans was shown to be significant in this study.

Low-Dose Abdominal CT for Evaluating Suspected Appendicitis: Recommendations for CT Imaging Techniques and Practical Issues

A vast disparity exists between science and practice for CT radiation dose. Despite high-level evidence supporting the use of low-dose CT (LDCT) in diagnosing appendicitis, a recent survey showed that many care providers were still concerned that the low image quality of LDCT may lead to incorrect diagnoses. For successful implementation of LDCT practice, it is important to inform and educate the care providers not only of the scientific discoveries but also of concrete guidelines on how to overcome more practical matters. Here, we discuss CT imaging techniques and other practical issues for implementing LDCT practice.

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.

Muscle volume evaluation using 3DCT for congenital clubfoot

Background

In congenital clubfoot, the lower leg is very thin and the calf muscles are hypoplasic. However, there are few studies reporting real muscle volume.

Purpose

The purpose of this study is to assay the muscle volume in congenital clubfoot using 3DCT and to quantify the degree of the hypoplasia.

Material and methods

From January 2015 to December 2016, nine consecutive patients, seven male and two female, with unilateral congenital clubfeet were recruited for CT scans. Axial transverse sectional CT scans were acquired from the delineation of the fibular head to the tibial plafond. From the data, we rendered the entire muscle in 3D for muscle volume assay, and further segmented the posterior musculature for comparison between the normal and affected sides.

Results

The whole muscle volume on the normal side was 291.23 cm³ (181.23–593.49) and that on the affected side was 225.08 cm³ (120.71–429.08), for an affected side to normal side ratio of 0.79 (0.72–0.9), which was significantly smaller (p < .01). Posterior muscle volume on the normal side was 175.81 cm³ (103.72–376.32) and that on the affected side was 106.52 cm³ (58.3–188.39). The ratio of posterior muscle to whole muscle on the normal side was 0.62 (0.46–0.75), and that on the affected side was 0.48 (0.4–0.55), such that the affected side was significantly smaller (p < .01)

Conclusion

This study contributes quantitative data supporting the longstanding observations that the posterior calf muscles are significantly smaller on the affected side compared to the normal side in congenital clubfoot, and further underscores the importance of the extending the excursion of these muscles.

ALIGNING VIDEO-AND STRUCTURED DATA FOR IMAGING OPTIMISATION

Imaging optimisation can benefit from combining structured data with qualitative data in the form of audio and video recordings. Since video is complex to work with, there is a need to find a workable solution that minimises the additional time investment. The purpose of the paper is to outline a general workflow that can begin to address this issue. What is described is a data management process comprising the three steps of collection, mining and contextualisation. This process offers a way to work systematically and at a large scale without succumbing to the context loss of statistical methods. The proposed workflow effectively combines the video and structured data to enable a new level of insights in the optimisation process.

Computed tomography for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease

BACKGROUND

Hepatocellular carcinoma occurs mostly in people with chronic liver disease and ranks sixth in terms of global incidence of cancer, and fourth in terms of cancer deaths. In clinical practice, computed tomography (CT) is used as a second-line diagnostic imaging modality to confirm the presence of focal liver lesions suspected as hepatocellular carcinoma on prior diagnostic test such as abdominal ultrasound or alpha-foetoprotein, or both, either in surveillance programmes or in clinical settings. According to current guidelines, a single contrast-enhanced imaging study CT or magnetic resonance imaging (MRI) showing typical hallmarks of hepatocellular carcinoma in people with cirrhosis is valid to diagnose hepatocellular carcinoma. However, a significant number of hepatocellular carcinomas do not show typical hallmarks on imaging modalities, and hepatocellular carcinoma is, therefore, missed. There is no clear evidence of the benefit of surveillance programmes in terms of overall survival: the conflicting results can be a consequence of inaccurate detection, ineffective treatment, or both. Assessing the diagnostic accuracy of CT may clarify whether the absence of benefit could be related to underdiagnosis. Furthermore, an assessment of the accuracy of CT in people with chronic liver disease, who are not included in surveillance programmes is needed for either ruling out or diagnosing hepatocellular carcinoma.

OBJECTIVES

Primary: to assess the diagnostic accuracy of multidetector, multiphasic contrast-enhanced CT for the diagnosis of hepatocellular carcinoma of any size and at any stage in adults with chronic liver disease, either in a surveillance programme or in a clinical setting. Secondary: to assess the diagnostic accuracy of CT for the diagnosis of resectable hepatocellular carcinoma in adults with chronic liver disease.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Trials Register, Cochrane Hepato-Biliary Diagnostic-Test-Accuracy Studies Register, the Cochrane Library, MEDLINE, Embase, LILACS, Science Citation Index Expanded, and Conference Proceedings Citation Index - Science until 4 May 2021. We applied no language or document-type restrictions.

SELECTION CRITERIA

Studies assessing the diagnostic accuracy of CT for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease, with cross-sectional designs, using one of the acceptable reference standards, such as pathology of the explanted liver and histology of resected or biopsied focal liver lesion with at least a six-month follow-up.

DATA COLLECTION AND ANALYSIS

At least two review authors independently screened studies, extracted data, and assessed the risk of bias and applicability concerns, using the QUADAS-2 checklist. We presented the results of sensitivity and specificity, using paired forest plots, and tabulated the results. We used a hierarchical meta-analysis model where appropriate. We presented uncertainty of the accuracy estimates using 95% confidence intervals (CIs). We double-checked all data extractions and analyses.

MAIN RESULTS

We included 21 studies, with a total of 3101 participants. We judged all studies to be at high risk of bias in at least one domain because most studies used different reference standards, often inappropriate to exclude the presence of the target condition, and the time-interval between the index test and the reference standard was rarely defined. Regarding applicability in the patient selection domain, we judged 14% (3/21) of studies to be at low concern and 86% (18/21) of studies to be at high concern owing to characteristics of the participants who were on waiting lists for orthotopic liver transplantation. CT for hepatocellular carcinoma of any size and stage: sensitivity 77.5% (95% CI 70.9% to 82.9%) and specificity 91.3% (95% CI 86.5% to 94.5%) (21 studies, 3101 participants; low-certainty evidence). CT for resectable hepatocellular carcinoma: sensitivity 71.4% (95% CI 60.3% to 80.4%) and specificity 92.0% (95% CI 86.3% to 95.5%) (10 studies, 1854 participants; low-certainty evidence). In the three studies at low concern for applicability (861 participants), we found sensitivity 76.9% (95% CI 50.8% to 91.5%) and specificity 89.2% (95% CI 57.0% to 98.1%). The observed heterogeneity in the results remains mostly unexplained. The sensitivity analyses, which included only studies with clearly prespecified positivity criteria and only studies in which the reference standard results were interpreted without knowledge of the results of the index test, showed no variation in the results.

AUTHORS' CONCLUSIONS

In the clinical pathway for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease, CT has roles as a confirmatory test for hepatocellular carcinoma lesions, and for staging assessment. We found that using CT in detecting hepatocellular carcinoma of any size and stage, 22.5% of people with hepatocellular carcinoma would be missed, and 8.7% of people without hepatocellular carcinoma would be unnecessarily treated. For resectable hepatocellular carcinoma, we found that 28.6% of people with resectable hepatocellular carcinoma would improperly not be resected, while 8% of people without hepatocellular carcinoma would undergo inappropriate surgery. The uncertainty resulting from the high risk of bias in the included studies and concerns regarding their applicability limit our ability to confidently draw conclusions based on our results.

Factors affecting high cumulative radiation exposure from paediatric computed tomography

Purpose

To estimate occurrence rate of high cumulative radiation exposure from paediatric computed tomography (CT), and to determine influential factors on high-dose inclination.

Material and methods

Patients below 18 years old receiving at least 50 mSv of a cumulative dose during a 5-year period in a tertiary care centre were retrospectively enrolled. Individual patient characteristics, diagnoses, frequency of exa-minations, scanner sites, designated scans, and effective doses were recorded. Collective doses were compared among groups of the diagnoses and scanner sites, and regression analyses were applied.

Results

Of 2771 patients, 3.2% received individual cumulative doses between 50 and 303 mSv (median, 74 mSv). Frequency of examinations ranged from 1 to 13 times (median, 4 times) per patient. About 70% of the patients had oncological illness. Radiation was predominantly high in a CT simulator that could contribute the percentage of collective dose to twice that of examinations owing to higher scanning parts and CT dose index. Some scanner sites used higher acquisition phases. Regression analysis showed that the number of scanning parts and phases significantly influenced the cumulative dose inclination (p < 0.05) while frequent examinations did not.

Conclusions

There was a low occurrence of paediatrics with high dose accumulation. Significant factors affecting potentially high exposure were customized CT protocols in the specific scanners.

Sinogram-based deep learning image reconstruction technique in abdominal CT: image quality considerations

OBJECTIVES

To investigate the image quality and perception of a sinogram-based deep learning image reconstruction (DLIR) algorithm for single-energy abdominal CT compared to standard-of-care strength of ASIR-V.

METHODS

In this retrospective study, 50 patients (62% F; 56.74 ± 17.05 years) underwent portal venous phase. Four reconstructions (ASIR-V at 40%, and DLIR at three strengths: low (DLIR-L), medium (DLIR-M), and high (DLIR-H)) were generated. Qualitative and quantitative image quality analysis was performed on the 200 image datasets. Qualitative scores were obtained for image noise, contrast, small structure visibility, sharpness, and artifact by three blinded radiologists on a 5-point scale (1, excellent; 5, very poor). Radiologists also indicated image preference on a 3-point scale (1, most preferred; 3, least preferred). Quantitative assessment was performed by measuring image noise and contrast-to-noise ratio (CNR).

RESULTS

DLIR had better image quality scores compared to ASIR-V. Scores on DLIR-H for noise (1.40 ± 0.53), contrast (1.41 ± 0.55), small structure visibility (1.51 ± 0.61), and sharpness (1.60 ± 0.54) were the best (p < 0.05) followed by DLIR-M (1.85 ± 0.52, 1.66 ± 0.57, 1.69 ± 0.59, 1.68 ± 0.46), DLIR-L (2.29 ± 0.58, 1.96 ± 0.61, 1.90 ± 0.65, 1.86 ± 0.46), and ASIR-V (2.86 ± 0.67, 2.55 ± 0.58, 2.34 ± 0.66, 2.01 ± 0.36). Ratings for artifacts were similar for all reconstructions (p > 0.05). DLIRs did not influence subjective textural perceptions and were preferred over ASIR-V from the beginning. All DLIRs had a higher CNR (26.38-102.30%) and lower noise (20.64-48.77%) than ASIR-V. DLIR-H had the best objective scores.

CONCLUSION

Sinogram-based deep learning image reconstructions were preferred over iterative reconstruction subjectively and objectively due to improved image quality and lower noise, even in large patients. Use in clinical routine may allow for radiation dose reduction.

KEY POINTS

• Deep learning image reconstructions (DLIRs) have a higher contrast-to-noise ratio compared to medium-strength hybrid iterative reconstruction techniques. • DLIR may be advantageous in patients with large body habitus due to a lower image noise. • DLIR can enable further optimization of radiation doses used in abdominal CT.

Evaluation of Organ Dose and Image Quality Metrics of Pediatric CT Chest-Abdomen-Pelvis (CAP) Examination: An Anthropomorphic Phantom Study

The aim of this study is to investigate the impact of CT acquisition parameter setting on organ dose and its influence on image quality metrics in pediatric phantom during CT examination. The study was performed on 64-slice multidetector CT scanner (MDCT) Siemens Definition AS (Siemens Sector Healthcare, Forchheim, Germany) using various CT CAP protocols (P1–P9). Tube potential for P1, P2, and P3 protocols were fixed at 100 kVp while P4, P5, and P6 were fixed at 80 kVp with used of various reference noise values. P7, P8, and P9 were the modification of P1 with changes on slice collimation, pitch factor, and tube current modulation (TCM), respectively. TLD-100 chips were inserted into the phantom slab number 7, 9, 10, 12, 13, and 14 to represent thyroid, lung, liver, stomach, gonads, and skin, respectively. The image quality metrics, signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were obtained from the CT console. As a result, this study indicates a potential reduction in the absorbed dose up to 20% to 50% along with reducing tube voltage, tube current, and increasing the slice collimation. There is no significant difference (p > 0.05) observed between the protocols and image metrics.

BENCHMARKING OF A NEW AUTOMATIC CT RADIATION DOSE CALCULATOR

Information on patient radiation dose is essential to meet the radiation protection regulations and the demands of dose optimization. Vendors have developed different tools for patient dose assessment for radiological purposes. In this study, estimated effective doses derived from a new image-based software tool (DoseWatch, GE Healthcare) was benchmarked against the corresponding doses from a dose calculator (CT-Expo, SASCRAD) and a conversion coefficient method. Dose data from 150 adult patients (66 male and 84 female), who underwent CT head, abdominopelvic or chest examinations, were retrospectively collected using DoseWatch. Effective dose estimated by DoseWatch was significantly lower than that of CT-Expo and DLP-E (k) (p ≤ 0.001). For the organ doses, DoseWatch resulted in lower dose than CT-Expo for all the organs with the exception of testis (p ≤ 001) and eye lenses (p ≤ 0.026).

Development of size-specific institutional diagnostic reference levels for computed tomography protocols in neck imaging

PURPOSE

To develop size-specific institutional diagnostic reference levels (DRLs) for computed tomography (CT) protocols used in neck CT imaging (cervical spine CT, cervical CT angiography (CTA) and cervical staging CT) and to compare institutional to national DRLs.

MATERIALS AND METHODS

Cervical CT examinations (spine, n = 609; CTA, n = 505 and staging CT, n = 184) performed between 01/2016 and 06/2017 were included in this retrospective study. For each region and examination, the volumetric CT dose index (CTDI_vol) and dose-length product (DLP) were determined and binned into size bins according to patient water-equivalent diameter (d_w). Linear regression analysis was performed to calculate size-specific institutional DRLs for CTDI_vol and DLP, applying the 75th percentile as the upper limit for institutional DRLs. The mean institutional CTDI_vol and DLP were compared to national DRLs (CTDI_vol 20 mGy for cervical spine CT (DLP 300 mGycm) and cervical CTA (DLP 600 mGycm), and CTDI_vol 15 mGy for cervical staging CT (DLP 330 mGycm)).

RESULTS

The mean CTDI_vol and DLP (±standard deviation) were 15.2 ± 4.1 mGy and 181.5 ± 88.3 mGycm for cervical spine CT; 8.1 ± 4.3 mGy and 280.2 ± 164.3 mGycm for cervical CTA; 8.6 ± 1.9 mGy and 162.8 ± 85.0 mGycm for cervical staging CT. For all CT protocols, there was a linear increase in CTDI_vol and DLP with increasing d_w. For the CTDI_vol, size-specific institutional DRLs increased with d_w from 14 to 29 mGy for cervical spine CT, from 5 to 17 mGy for cervical CTA and from 8 to 13 mGy for cervical staging CT. For the DLP, size-specific institutional DRLs increased with d_w from 130 to 510 mGycm for cervical spine CT, from 140 to 640 mGycm for cervical CTA and from 140 to 320 mGycm for cervical staging CT. Institutional DRLs were lower than national DRLs by 81% and 67% for cervical spine CT (d_w = 17.8 cm), 43% and 51% for cervical CTA (d_w = 19.5 cm) and 59% and 53% for cervical staging CT (d_w = 18.8 cm) for CTDI_vol and DLP, respectively.

CONCLUSION

Size-specific institutional DRLs were generated for neck CT examinations. The mean institutional CTDI_vol and DLP values were well below national DRLs.

Perceptions and Use of Computed Tomography in a Hospital Emergency Department: Technicians' Perspectives

OBJECTIVE

This study traces the evolution of perceptions and use of computed tomography (CT) by radiology technicians in the emergency department (ED) of a hospital in Italy across a 7-year period.

BACKGROUND

The sociotechnical context of the CT room of an ED has been neglected by scientific research-potentially impacting safety.

METHOD

Two studies were performed, one in 2011 and one in 2018. Six CT technicians were involved in each. Structured interviews were performed to gather information on perceptions related to the evolution of the use of CT according to nine different factors-e.g. the level of complexity, and mental workload. Observations were performed on duration of exams, the flow of people, conversations, and any critical issues.

RESULTS

The CT technology is appreciated, used effectively and with confidence by CT technicians. From 2011-2018, the execution times of the exams have decreased but not the proportion of time dedicated to the patient. Expectations for future improvements are limited by issues concerning the design of both the user interface and the social context of the ED workplace.

CONCLUSIONS

The safety and efficiency of the system as a whole are greatly dependent on the competence of the CT technicians. CT manufacturers rely on this competence to help compensate for the deficiencies created by suboptimal user interfaces and the lack of fit of the technology with the social context of the workplace.

APPLICATION

Training programs aimed at improving the management of relationships and communications between staff could improve performance and efficiency. CT manufacturers should try to better understand the cognitive and operational context of the workplaces where CT technicians work-and to design better diagnostic technology which accounts for these operational realities.

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.

Establishing how patient size and degree of miscentring affect CTDIvol, using patient data from a dose tracking system

OBJECTIVES

The work aimed to investigate and model the relationship between CT dose index (CTDI_vol), patient size and miscentring metrics using data extracted from a dose tracking software tool. Further, using the established model we aimed to extract and estimate further AEC metrics and, finally, demonstrate how the CTDI_vol may vary across a range of imaging exams and with variations in patient size, positional metrics and with scan parameters.

METHODS

CT scan parameters, patient dose metrics, patient positioning information and patient and water equivalent diameter information was extracted from abdomen, thorax-abdomen-pelvis and thorax imaging exams acquired on a 128-slice Siemens Somatom Definition AS + CT system using dose tracking software over a 1 year period. A miscentring factor, accounting for the magnification of the patient due to miscentring was derived. Significant predictors ( p-value < 0.001) of the CTDI_vol were considered as inputs into the model following regression analysis.

RESULTS

The model was capable of describing the CTDI_vol and its variation with patient miscentring and patient size. AEC parameters, such as the reference CTDI_vol, reference diameter and the AEC strength were estimated. Further, the model allowed for comparisons of how changes in scan settings, such as kVp, pitch and slice thickness affected CTDI_vol.

CONCLUSIONS

We demonstrate the use of clinical data, extracted from dose tracking software, to investigate and monitor AEC behaviour and CT output.

ADVANCES IN KNOWLEDGE

The presented model allows for the remote investigation of AEC behaviour using patient data.

Pediatric CT radiation exposure: where we were, and where we are now

Since the turn of the last millennium, the pediatric radiology community has blazed a patient-quality and safety trail in helping to effectively address the public and the news media's concerns about the implications of ionizing radiation from CT scanners in children. As such, this article (1) reviews the potential deleterious effects of ionizing radiation, (2) discusses why limiting radiation exposure in children is so important, (3) tells the history of pediatric CT radiation exposure concerns, (4) explains the interventions that took place to address these concerns and (5) touches on the current school of thought on pediatric CT dose reduction.

Coronary CT angiography radiation dose trends: A 10-year analysis to develop institutional diagnostic reference levels

PURPOSE

To develop institutional diagnostic reference levels (IDRL) for coronary CT angiography (CCTA) according to patient size by analyzing radiation dose changes over the past 10 years.

MATERIALS AND METHODS

This IRB approved retrospective investigation analyzed radiation dose data from CCTA between 2007 and 2016 at our institution. Annual trends in radiation dose were described for each scanner type and scanning mode. Radiation levels were analyzed for normorhythmic patients, patients with prior coronary artery bypass grafting (CABG), arrhythmia, and according to patient size and tube voltage. Median, and quartile values for volume CT dose index (CTDIvol), dose-length product (DLP), and size-specific dose estimate (SSDE) were calculated. Wilcoxon rank-sum test and Kruskal Wallis test were performed to assess the significance of quantitative data.

RESULTS

35,375 examinations from 33,317 patients (median age, 58 [50-66] years; male patients, 21,087 [58.7%]) were analyzed. CTDIvol, DLP, and SSDE significantly decreased by 9.0%, 30.8%, and 40.1% (all P < 0.05) for all examinations, respectively. All radiation dose metrics progressively decreased across scanning modes (especially retrospectively ECG-gated spiral and prospectively ECG-triggered high-pitch spiral acquisition mode), but did not significantly change across scanners in the last 6 years. CTDIvol and DLP increased with patient size when water-equivalent diameters were >19 cm for normorhythmic and CABG patients. In arrhythmic patients, CTDIvol increased progressively with water-equivalent diameters across all groups.

CONCLUSION

CCTA radiation dose has progressively decreased in the past decade except in patients with prior CABG and arrhythmia. Size-specific IDRLs may optimize radiation utilization in these patients going forward.

Optimization of CT protocols using cause-and-effect analysis of outliers

The aim of this study was to implement an outlier marking and analysis methodology to optimize CT examination protocols. CT Head examination data, including dose metrics along with technical parameters, were stored in an automatic dose registry system. Reference dose metrics distribution was obtained throughout a 1-year period. Outlier thresholds were calculated taking into account the specific shape of the distribution, by using a robust measure of the skewness; the medcouple parameter. Subsequently, outliers from a 4-month period were marked and Cause-and-Effect analysis was carried out by a multidisciplinary dose committee. Reference Dose metrics distributions were obtained from 3690 CT Head examinations. Both CTDIvol and DLP showed a certain degree of skewness, with a medcouple value of 0.05 and 0.11, respectively. All of the upper-outliers fell within 3 identifiable groups of causes, ordered by relative importance: i) inadequate protocol selection, ii) arms or objects in the field-of-view, and iii) abnormal scanning region diameter. Regarding the lower-outliers, 90% were attributable to the inclusion of additional series in the original head protocol and the remaining 10% to unknown causes. Also, a general Cause-and-Effect diagram for outliers was elaborated. While the Dose Reference Level method applies to the general performance of a CT protocol and allows comparison with other centers, the outlier method represents a step further in the optimization process. The proposed method focuses on detecting incorrect utilization of the CT, which mainly arises from inadequate knowledge of CT technology.

Radiographers' experience of risks for patient safety incidents in the radiology department

AIMS AND OBJECTIVES

To describe potential risks for patient safety incidents in the radiology department from a radiographer's perspective.

BACKGROUND

A radiology department is a high-tech environment with high communication activity between different healthcare systems in combination with a large patient flow. Risks for patient safety incidents exist in every phase of a radiological examination. Due to the nature of the activity, a radiology department needs to have its own range of measures to prevent risks linked to radiology.

DESIGN

A qualitative descriptive design.

METHODS

Semi-structured interviews were carried out with 17 radiographers during the period September 2015 to February 2016. The data were analysed using conventional content analysis. This study followed the COREQ checklist criteria for the reporting of qualitative research.

RESULTS

The analysis yielded 20 different patient safety incidents that could result in the following six types of healthcare-associated harm: Patients could be exposed to unnecessary radiation; patients could receive an inaccurate diagnosis; patients could incur drug-induced damage; patients could suffer direct physical injury; or, their examination and treatment could be delayed or not carried out; or, their general health condition could deteriorate.

CONCLUSION

Lack of communication and knowledge, both internally and externally, can increase risks for patient safety incidents. The study describes a complex chain of activities that represent risks in the radiology department. It needs to be pointed out that it is not always the activities in the radiology department that cause the harm.

RELEVANCE TO CLINICAL PRACTICE

To carry out preventive patient safety work, a comprehensive analysis of the entire care chain is required. Patient safety work should also focus on improvement in communication both internally, within the radiology department, and externally. Standardised methodological guidelines, consistent prescriptions of method from the radiologist and a good working environment are internal success factors for patient safety at the radiology department.

Dual-Energy Computed Tomography: Dose Reduction, Series Reduction, and Contrast Load Reduction in Dual-Energy Computed Tomography

Evolution in computed tomography technology and image reconstruction have significantly changed practice. Dual energy computed tomography is being increasingly adopted owing to benefits of material separation, quantification, and improved contrast-to-noise ratio. The radiation dose can match that from single energy computed tomography. Spectral information derived from a polychromatic x-ray beam at different energies yields in image reconstructions that reduce the number of phases in a multiphasic examination and decrease the absolute amount of contrast media. This increased analytical and image processing capability provides new avenues for addressing radiation dose and iodine exposure concerns.

Inter-laboratory comparison of channelized hotelling observer computation

PURPOSE

The task-based assessment of image quality using model observers is increasingly used for the assessment of different imaging modalities. However, the performance computation of model observers needs standardization as well as a well-established trust in its implementation methodology and uncertainty estimation. The purpose of this work was to determine the degree of equivalence of the channelized Hotelling observer performance and uncertainty estimation using an intercomparison exercise.

MATERIALS AND METHODS

Image samples to estimate model observer performance for detection tasks were generated from two-dimensional CT image slices of a uniform water phantom. A common set of images was sent to participating laboratories to perform and document the following tasks: (a) estimate the detectability index of a well-defined CHO and its uncertainty in three conditions involving different sized targets all at the same dose, and (b) apply this CHO to an image set where ground truth was unknown to participants (lower image dose). In addition, and on an optional basis, we asked the participating laboratories to (c) estimate the performance of real human observers from a psychophysical experiment of their choice. Each of the 13 participating laboratories was confidentially assigned a participant number and image sets could be downloaded through a secure server. Results were distributed with each participant recognizable by its number and then each laboratory was able to modify their results with justification as model observer calculation are not yet a routine and potentially error prone.

RESULTS

Detectability index increased with signal size for all participants and was very consistent for 6 mm sized target while showing higher variability for 8 and 10 mm sized target. There was one order of magnitude between the lowest and the largest uncertainty estimation.

CONCLUSIONS

This intercomparison helped define the state of the art of model observer performance computation and with thirteen participants, reflects openness and trust within the medical imaging community. The performance of a CHO with explicitly defined channels and a relatively large number of test images was consistently estimated by all participants. In contrast, the paper demonstrates that there is no agreement on estimating the variance of detectability in the training and testing setting.

Effect of an Arm Traction Device on Image Quality and Radiation Exposure during Neck CT: A Prospective Study

BACKGROUND AND PURPOSE

The image quality of neck CT is frequently disturbed by streak artifact from the shoulder girdles. Our aim was to determine the effects of an arm traction device on image quality and radiation exposure in neck CT.

MATERIALS AND METHODS

Patients with lymphoma with complete remission who were scheduled to undergo 2 consecutive follow-up neck CT scans for surveillance within a 1-year interval were enrolled in this prospective study. They underwent 2 consecutive neck CT scans (intervention protocol: patients with an arm traction device; standard protocol: no positioning optimization) on the same CT system. The primary outcome measures were image noise in the lower neck and dose-length product. Secondary outcomes were streak artifacts in the supraclavicular fossa, volume CT dose index, and the extent of the biacromial line shift.

RESULTS

Seventy-three patients were enrolled and underwent 2 consecutive CT scans with a mean interval of 155 days. In the intervention protocol, a mean noise reduction in the lower neck of 25.2%-28.5% (P < .001) was achieved, and a significant decrease in dose-length product (413 versus 397, P < .001) was observed. The intervention protocol significantly decreased streak artifacts (P < .001) and volume CT dose index (13.9 versus 13.4, P < .001) and could lower the biacromial line an average of 2.1 cm.

CONCLUSIONS

An arm traction device can improve image quality and reduce radiation exposure during neck CT. The device can be simply applied in cooperative patients with suspected lower neck lesions, and the approach offers distinct advantages over the conventional imaging protocol.