Are referral guidelines for CT examinations addressing all clinical scenarios? A comparison of EURO-2000 Guidelines and ESR iGuide.

OBJECTIVES: To investigate the proportion of clinical scenarios covered by EURO-2000 Guidelines and ESR iGuide, and assess compliance with both guidelines. METHODS: The clinical indication on archived request forms for head, chest, abdomen-pelvis, and spine CT examinations performed in three hospitals in January 2018 was retrospectively matched with EURO-2000 Guidelines and ESR iGuide. For clinical scenarios addressed in the guidelines, the compliance with the guidelines was assessed. Analysis was performed on pooled data from the three centres and further stratified by centre, body region, and prescriber's specialisation. The differences in categorical data distributions between centres, body regions, and prescribers' specialisations were assessed with paired McNemar's χ2 tests. RESULTS: A total of 6,812 requests for 7,217 CT examinations were analysed. Sixty-five percent of clinical situations that lead to prescribing CT examinations were addressed in EURO-2000 Guidelines compared with 81% for ESR iGuide. Proportions of clinical scenarios covered by the guidelines were statistically different between centres and body regions (p < 0.001) and varied according to prescribers' specialisations (p ranging from < 0.001 to 0.531). Both EURO-2000 Guidelines and ESR iGuide encompassed more clinical scenarios in certain body regions, favouring, e.g. spine and head over abdomen and chest. The proportion of "unjustified examinations" was greater according to EURO-2000 Guidelines (46%) than ESR iGuide (23%) (p < 0.001). CONCLUSIONS: Both EURO-2000 Guidelines and ESR iGuide do not address numerous common clinical scenarios. The proportions of scenarios addressed differ according to the centre, body region, and prescribers' specialisation. Any estimation of compliance with referral guidelines is therefore of relative significance. KEY POINTS: • ESR iGuide performs better than earlier EURO-2000 Guidelines for the coverage of all possible clinical scenarios leading to CT referrals. • Differences in coverage of clinical scenarios by both referral guidelines are observed for different body regions and/or prescribers' subspecialties. • As referral guidelines are incomplete, any estimation of justified or unjustified CT requests is of relative significance.

Variabilities in X-ray diagnostic reference levels.

OBJECTIVES: To estimate the variability of X-ray diagnostic reference levels (DRLs) depending on the number of X-ray devices and data per device. METHODS: Dose-area products (DAP) were collected by the national nuclear control agency from the 590 devices installed in 345 medical centers in the country. From 2015 to 2017, the number of chest (postero-anterior (PA) view alone, and both postero-anterior and lateral views (PA/LAT)), abdomen, pelvis, and lumbar spine examinations collected in these centers ranged from 23,000 to 77,000. The impact of the number of devices and DAP data per device on DRLs' variabilities (95th confidence intervals divided by medians) is estimated using a bootstrapping method as a function of the number of devices and DAP per device. RESULTS: The DRLs' variabilities ranged from 30 to 200% depending on the number of devices and DAP data per device but stabilized at 30% when the number of devices was higher than 200 for chest PA and abdomen examinations, 300 for lumbar spine and pelvis examinations, and 400 for chest PA/LAT examinations, regardless of the number of DAP data per device. Extrapolations of our results suggest that thousands of devices are necessary to reduce DRLs' variabilities to 10%. CONCLUSION: DAP-related DRL variabilities are high but only moderately influenced by the number of DAP data per device and of devices provided this number is higher than 200 to 400 devices according to the type of examination. Harmonization of methods of data collection between the authorities of the EU states should be recommended. KEY POINTS: • DAP-related DRLs are not fixed values but ranges of values with at least 30% variability. • DAP-related DRLs strongly depend on the number of devices included when lower than 100. • If the number of devices included exceeds 200 to 400, the DRLs' variabilities do not depend on the number of DAP per device and should not exceed 30%.

CT diagnostic reference levels: are they appropriately computed?

OBJECTIVES: To estimate the variability of CT diagnostic reference levels (DRLs) according to the methods used for computing collected data. METHODS: Dose-length products (DLP) were collected by our national nuclear control agency from the 250 devices installed in 140 medical centers in the country. In 2015, the number of head, thorax, abdomen, and lumbar spine examinations collected in these centers ranged from approximately 20,000 to 42,000. The impact on DRLs of the number of devices considered, as well as the differences in descriptive statistics (mean vs. median DLP) or methods of pooling DLP data (all devices vs. all patients), was investigated. Variability in DRLs was investigated using a bootstrapping method as a function of the numbers of devices and examinations per device. RESULTS: As expected, DRLs derived from means were higher than those from medians, with substantial differences between device- and patient-related DRLs. Depending on the numbers of devices and DLP data per device, the variability ranged from 10 to 40% but was stabilized at a level of 10-20% if the number of devices was higher than 50 to 60, regardless of the number of DLP data per device. CONCLUSION: Number of devices and of DLP data per device, descriptive statistics, and pooling data influence DRLs. As differences in methods of computing survey data can artificially influence DRLs, harmonization among national authorities should be recommended. KEY POINTS: • Due to CT dose variability, that of DRLs is at least of 10%. • DRLs derived from medians are lower than from means and differ from those obtained by pooling all patient data. • Fifty to 60 devices should be sufficient for estimating national DRLs, regardless of the number of data collected per device.

X-ray examination dose surveys: how accurate are my results?

OBJECTIVES: To determine the variabilities of dose-area-products (DAP) of frequent X-ray examinations collected for comparison with diagnostic reference levels (DRLs). METHODS: DAP values of chest, abdomen, and lumbar spine examinations obtained on devices from two manufacturers were collected in three centers over 1 to 2 years. The variability of the average DAP results defined as the 95% confidence interval in percentage of their median value was calculated for increasing sample sizes, each examination and center. We computed the sample sizes yielding variabilities lower or equal to 25% and 10%. The effect of narrowing patient selection based on body weight was also investigated (ranges of 67-73 Kg, or 60-80 Kg). RESULTS: DAP variabilities ranged from 75 to 170% of the median value when collecting small samples (10 to 20 DAP). To reduce this variability, larger samples are needed, collected over up to 2 years, regardless of the examination and center. A variability ≤ 10% could only be reached for chest X-rays, requiring up to 800 data. For the abdomen and lumbar spine, the lowest achievable variability was 25%, regardless of the body weight selection, requiring up to 400 data. CONCLUSION: Variabilities in DAP collected through small samples of ten data as recommended by authorities are very high, but can be reduced down to 25% (abdomen and lumbar spine) or even 10% (chest) through a substantial increase in sample sizes. Our findings could assist radiologists and regulatory authorities in estimating the reliability of the data obtained when performing X-ray dose surveys. KEY POINTS: • Low but reasonable variabilities cannot be reached with samples sized as recommended by regulatory authorities. Higher numbers of DAP values are required to reduce the variability. • Variabilities of 10% for the chest and 25% for abdomen and lumbar spine examinations are achievable, provided large samples of data are collected over 1 year. • Our results could help radiologists and authorities interpret X-rays dose surveys.

Radiation protection: Factors influencing compliance to referral guidelines in minor chest trauma.

OBJECTIVES: To test the hypothesis that referral guidelines are not sufficiently known by prescribers and that medico-legal concerns could influence the prescription of radiographs in minor chest trauma. METHODS: We submitted a questionnaire including a typical clinical history and questions on reasons for prescribing radiographs of the ribs in minor chest trauma to 112 prescriptors (33 residents, 18 surgeons, 7 internists, 24 general practitioners and 30 ER physicians). All accepted to participate. Comparisons were performed by Fisher's exact test followed by a post-hoc analysis and by a McNemar test. RESULTS: Fifty-eight percent of prescriptors proposed rib radiographs, most (89%) being unaware of the guidelines. Only 11% of them changed their intention to order radiographs after information on referral guidelines and radiation dose (P=0.057). The mean dose delivered by rib radiographs was 38 times higher than that of a chest X-ray. Legal and medico-legal concerns (requirements from insurance policies and avoidance of lawsuits) were the main reasons for requesting radiographs. CONCLUSION: Unsharpness of guidelines in addition to social and medico-legal issues, rather than medical reasons or the lack of knowledge of the guidelines, strongly influence the prescription of radiographs of the ribs in minor chest trauma. KEY POINTS: • Most prescriptors order radiographs of the ribs in minor chest trauma. • Only few prescriptors are aware of referral guidelines. • Information on guidelines does not change their need for radiographs. • Motivations for ordering radiographs are rather legal than medical, but poor compliance to guidelines could also be explained by their unsharpness. • Radiation dose of rib radiographs was 38 times that of a PA chest radiograph.

CT dose survey in adults: what sample size for what precision?

OBJECTIVES: To determine variability of volume computed tomographic dose index (CTDIvol) and dose-length product (DLP) data, and propose a minimum sample size to achieve an expected precision. METHODS: CTDIvol and DLP values of 19,875 consecutive CT acquisitions of abdomen (7268), thorax (3805), lumbar spine (3161), cervical spine (1515) and head (4106) were collected in two centers. Their variabilities were investigated according to sample size (10 to 1000 acquisitions) and patient body weight categories (no weight selection, 67-73 kg and 60-80 kg). The 95 % confidence interval in percentage of their median (CI95/med) value was calculated for increasing sample sizes. We deduced the sample size that set a 95 % CI lower than 10 % of the median (CI95/med ≤ 10 %). RESULTS: Sample size ensuring CI95/med ≤ 10 %, ranged from 15 to 900 depending on the body region and the dose descriptor considered. In sample sizes recommended by regulatory authorities (i.e., from 10-20 patients), mean CTDIvol and DLP of one sample ranged from 0.50 to 2.00 times its actual value extracted from 2000 samples. CONCLUSIONS: The sampling error in CTDIvol and DLP means is high in dose surveys based on small samples of patients. Sample size should be increased at least tenfold to decrease this variability. KEY POINTS: • Variability of dose descriptors is high regardless of the body region. • Variability of dose descriptors depends on weight selection and the region scanned. • Larger samples would reduce sampling errors of radiation dose data in surveys. • Totally or partially disabling AEC reduces dose variability and increases patient dose. • Median values of dose descriptors depend on the body weight selection.

Differentiating between Subsolid and Solid Pulmonary Nodules at CT: Inter- and Intraobserver Agreement between Experienced Thoracic Radiologists.

PURPOSE: To quantify the reproducibility and accuracy of experienced thoracic radiologists in differentiating between subsolid and solid pulmonary nodules at CT. MATERIALS AND METHODS: The institutional review board of Beth Israel Deaconess Medical Center approved this multicenter study. Six thoracic radiologists, with a mean of 21 years of experience in thoracic radiology (range, 17-22 years), selected images of 10 solid and 10 subsolid nodules to create a database of 120 nodules; this selection served as the reference standard. Each radiologist then interpreted 120 randomly ordered nodules in two different sessions that were separated by a minimum of 3 weeks. The radiologists classified whether or not each nodule was subsolid. Inter- and intraobserver agreement was assessed with a κ statistic. The number of correct classifications was calculated and correlated with nodule size by using Bland-Altman plots. The relationship between disagreement and nodule morphologic characteristics was analyzed by calculating the intraclass correlation coefficient. RESULTS: Interobserver agreement (κ) was 0.619 (range, 0.469-0.745; 95% confidence interval (CI): 0.576, 0.663) and 0.670 (range, 0.440-0.839; 95% CI: 0.608, 0.733) for interpretation sessions 1 and 2, respectively. Intraobserver agreement (κ) was 0.792 (95% CI: 0.750, 0.833). Averaged for interpretation sessions, correct classification was achieved by all radiologists for 58% (70 of 120) of nodules. Radiologists agreed with their initial determination (the reference standard) in 77% of cases (range, 45%-100%). Nodule size weakly correlated with correct classification (long axis: Spearman rank correlation coefficient, rs = 0.161 and P = .049; short axis: rs = 0.128 and P = .163). CONCLUSION: The reproducibility and accuracy of thoracic radiologists in classifying whether or not a nodule is subsolid varied in the retrospective study. This inconsistency may affect surveillance recommendations and prognostic determinations.

Short- and long-term effects of clinical audits on compliance with procedures in CT scanning.

PURPOSE: To test the hypothesis that quality clinical audits improve compliance with the procedures in computed tomography (CT) scanning. MATERIALS AND METHODS: This retrospective study was conducted in two hospitals, based on 6950 examinations and four procedures, focusing on the acquisition length in lumbar spine CT, the default tube current applied in abdominal un-enhanced CT, the tube potential selection for portal phase abdominal CT and the use of a specific "paediatric brain CT" procedure. The first clinical audit reported compliance with these procedures. After presenting the results to the stakeholders, a second audit was conducted to measure the impact of this information on compliance and was repeated the next year. Comparisons of proportions were performed using the Chi-square Pearson test. RESULTS: Depending on the procedure, the compliance rate ranged from 27 to 88 % during the first audit. After presentation of the audit results to the stakeholders, the compliance rate ranged from 68 to 93 % and was significantly improved for all procedures (P ranging from <0.001 to 0.031) in both hospitals and remained unchanged during the third audit (P ranging from 0.114 to 0.999). CONCLUSION: Quality improvement through repeated compliance audits with CT procedures durably improves this compliance. KEY POINTS: • Compliance with CT procedures is operator-dependent and not perfect. • Compliance differs between procedures and hospitals, even within a unified department. • Compliance is improved through audits followed by communication to the stakeholders. • This improvement is sustainable over a one-year period.

Organ-based tube current modulation: are women's breasts positioned in the reduced-dose zone?

PURPOSE: To retrospectively determine the potential of organ-based tube current modulation ( OBTCM organ-based tube current modulation ) to reduce the radiation dose delivered to breast tissue by computed tomography (CT) by determining breast angular position in relation to the zones of decreased versus increased radiation. MATERIALS AND METHODS: The authors obtained institutional review board approval for this study and patients' written informed consent. In two academic centers (center A: Beth Israel Deaconess Medical Center, Boston, Mass; and center B: Hôpital André Vésale, Montignies-le-Tilleul, Belgium), data were collected from clinical thoracic CT examinations performed in 498 women (mean age, 60 years; age range, 18-95 years) in the supine position and 34 women (mean age, 53 years; age range, 18-84 years) in the prone position. One radiologist in each center determined breast tissue location and measured its inner and outer boundaries with respect to the isocenter of the CT examination. The percentages of women with breast tissue within and those with breast tissue outside the zone of decreased radiation delivered by OBTCM organ-based tube current modulation were determined. The location of breast tissue was correlated with patient age and with sagittal and coronal diameters of the thorax by using the Student t test, Fisher exact test, and Pearson correlation. RESULTS: None of the women lying in the supine position had the entirety of the breast tissue located within the reduced-dose zone. Breast tissue was located in the increased-dose zone in 99% of women lying supine and in 82% of women lying prone. CONCLUSION: The breast angular position of almost all women was higher than the angular limit of the reduced versus the increased dose in OBTCM organ-based tube current modulation . No woman, regardless of supine or prone position, had all breast tissue within the reduced-dose zone.

Multidetector CT radiation dose optimisation in adults: short- and long-term effects of a clinical audit.

OBJECTIVE: To report short- and long-term effects of an audit process intended to optimise the radiation dose from multidetector row computed tomography (MDCT). METHODS: A survey of radiation dose from all eight MDCT departments in the state of Luxembourg performed in 2007 served as baseline, and involved the most frequently imaged regions (head, sinus, cervical spine, thorax, abdomen, and lumbar spine). CT dose index volume (CTDIvol), dose-length product per acquisition (DLP/acq), and DLP per examination (DLP/exa) were recorded, and their mean, median, 25th and 75th percentiles compared. In 2008, an audit conducted in each department helped to optimise doses. In 2009 and 2010, two further surveys evaluated the audit's impact on the dose delivered. RESULTS: Between 2007 and 2009, DLP/exa significantly decreased by 32-69 % for all regions (P < 0.001) except the lumbar spine (5 %, P = 0.455). Between 2009 and 2010, DLP/exa significantly decreased by 13-18 % for sinus, cervical and lumbar spine (P ranging from 0.016 to less than 0.001). Between 2007 and 2010, DLP/exa significantly decreased for all regions (18-75 %, P < 0.001). Collective dose decreased by 30 % and the 75th percentile (diagnostic reference level, DRL) by 20-78 %. CONCLUSIONS: The audit process resulted in long-lasting dose reduction, with DRLs reduced by 20-78 %, mean DLP/examination by 18-75 %, and collective dose by 30 %. KEY POINTS: • External support through clinical audit may optimise default parameters of routine CT. • Reduction of 75th percentiles used as reference diagnostic levels is 18-75 %. • The effect of this audit is sustainable over time. • Dose savings through optimisation can be added to those achievable through CT.

Dose reduction in cardiothoracic CT: review of currently available methods.

Radiation exposure from computed tomography (CT) has received much attention lately in the medical literature and the media, given the relatively high radiation dose that characterizes a CT examination. Although there are a variety of possible strategies for reducing radiation exposure from CT in an individual patient, optimal CT image acquisition requires that the radiologist understand new scanner technology and how to implement the most effective means of dose reduction while maintaining image quality. The authors describe a practical approach to dose reduction in cardiothoracic radiology, discussing CT radiation dose metrics (eg, CT dose index, dose-length product, effective diameter, and size-specific dose estimate) as well as CT scanner parameters that directly or indirectly influence radiation dose (eg, scan length, x-ray tube output, tube current modulation, pitch, image reconstruction techniques [including iterative reconstruction], and noise reduction). These variables are discussed in terms of their relative importance to image quality and the implications of parametric changes for image quality and diagnostic content, and practical recommendations are made for their immediate implementation in the clinical setting. Taken together, the principles of physics and key parameters involved in reducing radiation dose while maintaining image quality can serve as a "survival guide" for a diagnostic radiology practice.

Unusual Air Crescents on Chest Radiographs.

The air crescent (AC) is a common radiological sign. Even if its commonest aetiology remains pulmonary aspergillosis, various other causes have been described. In this study, we report four rare causes of ACs seen on chest radiographs that haven't been described in the literature. Teaching point: The differential diagnosis of an air crescent sign on chest radiographs includes oesophageal bezoar, interstitial lung emphysema, central bronchial stenosis and perforated emphysematous cholecystitis.

Radiographic Detection of Post-Traumatic Bone Fractures: Contribution of Artificial Intelligence Software to the Analysis of Senior and Junior Radiologists.

Objectives: The aims of this study were: (a) to evaluate the performance of an artificial intelligence (AI) software package (Boneview Trauma, Gleamer) for the detection of post-traumatic bone fractures in radiography as a standalone; (b) used by two radiologists (osteoarticular senior and junior); and (c) to determine to whom AI would be most helpful. Materials and Methods: Within 14 days of a trauma, 101 consecutive patients underwent radiographic examination of the upper or lower limbs. The definite diagnosis for identifying fractures was: (a) radio-clinical consensus between the radiologist on-call who analyzed the images and the orthopedist (Group 1); (b) Cone Beam computed tomography (CBCT) exploration of the area of interest, in case of doubts or absence of consensus (Group 2). Independently of this diagnosis for both groups, the radiographic images were separately analyzed by two radiologists (osteoarticular senior: SR; junior: JR) prior without, and thereafter with the results of AI. Results: AI performed better than the radiologists in detecting common fractures (Group 1), but not subtle fractures (Group 2). In association with AI, both radiologists increased their overall performances in both groups, whereas this increase was significantly higher for the JR (p < 0.05). Conclusion: AI is reliable for common radiographic fracture identification and is a useful learning tool for radiologists in training. However, the software's overall performance does not exceed that of an osteoarticular senior radiologist, particularly in case of subtle lesions.

A Caustic Hydrochloric Acid Enema: A Case Report.

Rectitis caused by the administration of a caustic enema is uncommonly encountered in routine clinical practice. The reasons given for the application of caustic enemas are diverse, including but not limited to suicide attempts, murder attempts, iatrogenic causes and simple mistakes. When caustic enemas do occur the consequences can be dire, resulting in extensive injury. These injuries often prove fatal in the short term, but if the patient survives the initial injuries, they may subsequently cause severe disability. Treatment can be conservative but commonly involves surgery, with a significant proportion of patients not surviving the intervention or succumbing to complications thereafter. We present the case of a patient with a history of alcoholism, depression and a recent recurrence of oesophageal cancer who self-administered a hydrochloric acid enema in an attempted suicide. The patient subsequently suffered a stenosis of the lower bowel, resulting in diarrhoea. A colostomy was performed in order to alleviate the patient's symptoms and improve their comfort.

Central Pulmonary Embolism Detected on a Chest X-Ray: A Case Report.

Patients presenting to the emergency room with respiratory symptoms often receive a chest X-ray as part of the initial workup to exclude common pathologies. A 60-year-old patient presented to the emergency department with dyspnoea. An initial chest X-ray revealed the Fleischner's sign, the knuckle sign, and the Westermark sign, specific but not sensitive for central pulmonary embolism, prompting a follow-up angio CT to confirm the diagnosis. The patient was treated and discharged a few days later. Teaching point: Chest X-rays, done as part of an initial workup, can show signs of pathologies that are not yet clinically suspected, such as pulmonary embolism.

Lobar Mucus Plugging Reflecting Central Bronchial Tumoral Obstruction: A Case Report.

Early diagnosis of bronchopulmonary carcinoid tumors is crucial as the surgical excision is the main treatment and determines the prognosis. We present the case of a 66-year-old heavy-smoker man who had started to complain about a cough a few months ago. We diagnosed him with an endobronchial mass on a chest computed tomography scan and lobar bronchoceles resulting from mucus plugging distal to the tumor obstruction. These findings were retrospectively visible on the previous chest radiograph that had initially been interpreted as non-contributary.

Aerated Lobar Collapse.

Teaching Point: Air trapping is a useful sign for early detection of worsening lobar collapse in the follow-up of obstructive atelectasis.

An Avoidable Cognitive Error in Chest Radiography.

Teaching Point: Awareness in radiology reporting of cognitive errors such as the alliterative bias can help minimize the delay to diagnosis and accelerate adequate patient care.

Reject Analysis in Digital Radiography and Computed Tomography: A Belgian Imaging Department Case Study.

Objective: Reject analysis is usually performed in digital radiography (DR) for quality assurance. Data for computed tomography (CT) rejects remains sparse. The aim of this study is to help provide a straightforward benchmark for reject analysis of both DR and CT. Materials and methods: This retrospective observational study included 107,277 DR and 20,659 CT during 18 months in a tertiary care center. Rejected acquisitions were retrieved by Dose Archiving and Communication System (DACS). The DR and CT reject analysis included reject rates, reasons for rejection and supplementary radiation dose associated with these rejects. Results: 8,904 rejected DR and 514 rejected CT were retrieved. The DR reject rate was 8.3% whereas the CT reject rate was 2.5%. The cumulative effective dose (ED) of DR rejects was 377.3 mSv while the cumulative ED of CT rejects was 1267.4 mSv. The major reason for rejects was positioning for both DR (61%) and CT (44%). Conclusion: This study helps constitute a simple reproducible method to analyze both DR and CT rejects simultaneously. Although CT rejects are less often monitored than DR rejects, the radiation dose associated with CT rejects is much higher, which emphasizes the need to systematically monitor both DR and CT rejects. Investigating the reasons and the most frequently rejected examinations gives an opportunity for improvement of imaging techniques in cooperation with technologists.