Are we overusing abdominal computed tomography scans in young patients referred in an emergency for acute abdominal pain?

Purpose: The primary objective was to assess the frequency of appropriateness of computed tomography (CT) for acute abdominal pain (AAP) in the emergency department; the secondary aim was to compare the diagnostic accuracy of ultra-sound (US) and CT in the diagnosis of the aetiology of AAP for diseases that can be diagnosed by US; and the third objective was to assess extent to which inappropriate CT examinations for AAP result in ionizing radiation exposure. Material and methods: In this retrospective single-centre study, we included patients aged between 15 and 46 years referred to the emergency department for AAP in 2016 and submitted to abdominal CT scans, collecting a total of 586 patients. In 152 patients with the more frequent pathologies, we compared the referral reason and current guidelines of the European Society of Radiology (ESR) IGUIDE®. Then we measured and compared the sensitivity of US and CT for the identification of the aetiology of AAP for diseases whose diagnosis can be reached by US. We also recorded the mean computed tomography dose index (CTDIvol), dose length product (DLP) and its standard deviation, and we calculated the effective dose (ED) using CT-Expo® software. Results: According to IGUIDE and based on the clinical suspicion of CT requests, CT examination was considered crucial in 264 (45.05%) patients. 322 patients had a referral reason for CT scan that could be considered "possibly appropriate" according Iguide criteria (4, 5, 6 scoring). Of these, 135 had an inappropriate CT request according to image findings. Conclusions: A better clinical framing and a correct interpretation of the reference guidelines could reduce unjustified exposure to ionizing radiation.

Preventable fatal injury during rally race: a multidisciplinary approach.

INTRODUCTION: The motor vehicle crash (MVC) constitutes an important challenge for forensic pathology in order to identify the manner and cause of death. Our study focuses on a fatal accident during a rally race corresponding to MVC sub-category. MATERIALS AND METHOD: Postmortem computed tomography (PMCT) was performed before the conventional autopsy. Autoptic and PMCT data were compared. Data collection allowed analyzing biomechanical dynamics of the incident and post-traumatic injuries through qualitative-statistics and solicitation quantitative indices. RESULTS: Photo and circumstantial evidence analysis showed a wrong installation of double shoulder belt system of head and neck support (HANS) collar. PMTC clearly highlighted multiple and bilateral fractures involving roof and base of skull; a displaced fracture of the right acetabulum was also encountered. Autopsy confirmed PMCT data and revealed a brainstem laceration. AIS (Abbreviated Injury Scale) achieved a maximum score in consideration of fatal injuries. DISCUSSION: The injuries analysis resulting from photographic surveys examination, conventional autopsy, and PMCT has led us to confirm a fatal front collision with a tree trunk. Head trauma represents a major injury in the present case. In this case, head injuries, related to whiplash trauma, are a consequence of a double shoulder belt system (HANS collar component) wrong installation. CONCLUSION: MVC and especially high-speed motor racing represent an important death cause. There was, for this reason, a marked development of cars and occupants' safety systems, such as HANS collar. PMCT improves the diagnostic performance of conventional autopsy and increases forensic medical knowledge related to traumatic injuries.

Practical recommendations for the application of DE 59/2013.

The changes introduced with Council Directive 2013/59/Euratom will require European Member States adapt their regulations, procedures and equipment to the new high standards of radiation safety. These new requirements will have an impact, in particular, on the radiology community (including medical physics experts) and on industry. Relevant changes include new definitions, a new dose limit for the eye lens, non-medical imaging exposures, procedures in asymptomatic individuals, the use and regular review of diagnostic reference levels (including interventional procedures), dosimetric information in imaging systems and its transfer to the examination report, new requirements on responsibilities, the registry and analysis of accidental or unintended exposure and population dose evaluation (based on age and gender distribution). Furthermore, the Directive emphasises the need for justification of medical exposure (including asymptomatic individuals), introduces requirements concerning patient information and strengthens those for recording and reporting doses from radiological procedures, the use of diagnostic reference levels, the availability of dose-indicating devices and the improved role and support of the medical physics experts in imaging.

Protecting sensitive patient groups from imaging using ionizing radiation: effects during pregnancy, in fetal life and childhood.

The frequency of imaging examinations requiring radiation exposure in children (especially CT) is rapidly increasing. This paper reviews the current evidence in radiation protection in pediatric imaging, focusing on the recent knowledge of the biological risk related to low doses exposure. Even if there are no strictly defined limits for patient radiation exposure, it is recommended to try to keep doses as low as reasonably achievable (the ALARA principle). To achieve ALARA, several techniques to reduce the radiation dose in radiation-sensitive patients groups are reviewed. The most recent recommendations that provide guidance regarding imaging of pregnant women are also summarized, and the risk depending on dose and phase of pregnancy is reported. Finally, the risk-benefit analysis of each examination, and careful communication of this risk to the patient, is emphasized.

Overdiagnosis and overimaging: an ethical issue for radiological protection.

AIMS AND OBJECTIVES: This study aimed to analyse the key factors that influence the overimaging using X-ray such as self-referral, defensive medicine and duplicate imaging studies and to emphasize the ethical problem that derives from it. MATERIALS AND METHODS: In this study, we focused on the more frequent sources of overdiagnosis such as the total-body CT, proposed in the form of screening in both public and private sector, the choice of the most sensitive test for each pathology such as pulmonary embolism, ultrasound investigations mostly of the thyroid and of the prostate and MR examinations, especially of the musculoskeletal system. RESULTS: The direct follow of overdiagnosis and overimaging is the increase in the risk of contrast media infusion, radiant damage, and costs in the worldwide healthcare system. The theme of the costs of overdiagnosis is strongly related to inappropriate or poorly appropriate imaging examination. CONCLUSIONS: We underline the ethical imperatives of trust and right conduct, because the major ethical problems in radiology emerge in the justification of medical exposures of patients in the practice. A close cooperation and collaboration across all the physicians responsible for patient care in requiring imaging examination is also important, balancing possible ionizing radiation disadvantages and patient benefits in terms of care.

Patient centring and scan length: how inaccurate practice impacts on radiation dose in CT colonography (CTC).

OBJECTIVE: The aim of this study was to acknowledge errors in patients positioning in CT colonography (CTC) and their effect in radiation exposure. MATERIALS AND METHODS: CTC studies of a total of 199 patients coming from two different referral hospitals were retrospectively reviewed. Two parameters have been considered for the analysis: patient position in relation to gantry isocentre and scan length related to the area of interest. CTDI vol and DLP were extracted for each patient. In order to evaluate the estimated effective total dose and the dose to various organs, we used the CT-EXPO® software version 2.2. This software provides estimates of effective dose and doses to the other various organs. RESULTS: Average value of the patients' position is found to be below the isocentre for 48 ± 25 mm and 29 ± 27 mm in the prone and supine position. It was observed that the increase in CTDI and DLP values for patients in Group 1, due to the inaccurate positioning, was estimated at about 30% and 20% for prone and supine position, respectively, while in Group 2, a decrease in CTDI and DLP values was estimated at about 16% and 18% for prone and supine position, respectively, due to an average position above isocentre. A dose increase ranging from 4 up to 13% was calculated with increasing the over-scanned region below anal orifice. CONCLUSION: Radiographers and radiologists need to be aware of dose variation and noise effects on vertical positioning and over-scanning. More accurate training need to be achieved even so when examination protocol varies from general practice.

Up-to-date imaging review of paediatric soft tissue vascular masses, focusing on sonography.

The purpose of this article is to provide an up-to-date overview on imaging of paediatric vascular soft tissue masses, including both neoplastic and non-neoplastic lesions. We describe the-often challenging-imaging diagnosis-mainly performed by ultrasound (and secondarily by MRI) and differential diagnosis of vascular soft tissue lesions in children. We underline how important it is to determine whether a vascular anomaly has a regional vascular origin, or if there are other entities, ranging from benign to malignant lesions, which have flow-signal or blood degradation products. Even though clinical examination and patient's history are the first and indispensable steps in the initial diagnosis, the role of imaging is crucial, not only to determine whether a mass represents a true tumour/pseudo-tumour, but also to achieve a more correct diagnosis and determine the extension of the tumour/pseudo-tumour and its relation with the nearby anatomic structures.

Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis): whole-body MR findings in two siblings with different subcutaneous nodules distribution.

Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis) is a rare, progressive, autosomal recessive disorder whose main hallmark is the deposition of amorphous hyaline material in soft tissues, with an evolutionary course and health impairment. It may present involvement of subcutaneous or periskeletal soft tissue, or may develop as a visceral infiltration entity with poor prognosis. Very few radiological data about this inherited condition have been reported, due to the extreme rarity of disease. We herein present a case of two siblings, affected by different severity of the disease, with different clinical features. They were examined by whole-body MR (WBMR) in order to assess different lesions localization, to rule out any visceral involvement and any other associated anomalies and to define patients' management.

Is MRI imaging in pediatric age totally safe? A critical reprisal.

Current radiological literature is strongly focussed on radiation imaging risks. Indeed, given there is a small but actual augment in cancer risk from exposure to ionizing radiation in children, it is important to understand what the risk of alternative techniques could be. We retrospectively review literature data concerning possible MR imaging risks, focussing on the biological effects of MR, sedation and gadolinium compound risks when dealing with infant patients. The main concerns can be summarized in: (1) Biological effects of non-ionizing electromagnetic fields (EMF) employed-whose mechanisms of interaction with human tissues are polarization, induced current, and thermal heating, respectively. (2) Risks associated with noises produced during MRI examinations. (3) Hazards from ferromagnetic external and/or implanted devices-whose risk of being unintentionally brought inside MR room is higher in children than in adults. (4) Risks associated with sedation or general anaesthesia, essential problem in performing MR in very young patients, due to the exam long-lasting. (5) Risks related to gadolinium-based contrast agents, especially considering the newly reported brain deposition.

Complete written/oral information about dose exposure in CT: is it really useful to guarantee the patients' awareness about radiation risks?

AIMS AND OBJECTIVES: According to the European directive 2013/59/Euratom, starting from February 2018, the information relating to patient exposure will be part of computed tomography (CT) reports, but the impact of this information on patients has not been deeply evaluated. Aim of our study was to evaluate patients' perception of radiation exposure related to routine CT and their understanding after communication of their dose exposure. MATERIALS AND METHODS: A survey, investigating patient's knowledge of radiation dose, was given to all adult patients (> 18 years) undergoing a CT examination both before and after CT scan. The first survey was the same for all patients. After CT scan, a second questionnaire was administered (after receiving the CT dose bill report and medical written and/or explanation about ionizing radiation risk). Results of the pre- and post-CT questionnaires responses were compared according to demographics characteristics and among the four post-CT groups. RESULTS: For some questions, statistically significant differences were found between the two centres. Seventy per cent of the patients answered that the presence of CT parameters in the report is considered useful. Even if not always statistically significant there was a slight increase in awareness of ionizing radiation risk comparing the pre- and post-CT surveys. The group that had both written and oral explanations had a better comprehension of CT dose bill (group III vs. I, p = 0.002). CONCLUSION: The way of communication of ionizing radiation risks did not affect the results of the post-CT survey. Indeed, the interest in the topic did not rise in the post-CT survey in any of the group. Adequate information about ionizing radiation risks provided together with dose exposure information may be useful. However, there is not a standardized better way of communicating information on ionizing radiation risks due to CT.

Radiation dose in non-dental cone beam CT applications: a systematic review.

BACKGROUND: Radiation-induced health risks are broadly questioned in the literature. As cone beam computed tomography (CBCT) is increasingly used in non-dental examinations, its effective dose needs to be known. This study aimed to review the published evidence on effective dose of non-dental CBCT for diagnostic use by focusing on dosimetry system used to estimate dose. MATERIALS AND METHODS: A systematic review of the literature was performed on 12 November 2017. All the literature up to this date was included. The PubMed and web of science databases were searched. Studies were screened for inclusion based on defined inclusion and exclusion criteria according to the preferred reporting items for systematic reviews. RESULTS: Fifteen studies met the inclusion criteria and were included in our review. Thirteen and two of them examined one and two anatomical areas, respectively. The anatomical areas were: ear (6), paranasal sinuses (4), ankle (3), wrist (2), knee (1), and cervical spine (1). Effective dose was estimated by different methods: (i) RANDO phantom associated with thermoluminescent dosimeters (6), metal oxide semiconductor field-effect transistor dosimeters (3), and optically stimulated luminescent dosimeters (1). (ii) Scanner outputs, namely computed tomography dose index (1) and dose area product (2). (iii) Monte Carlo simulations (2). CONCLUSION: CBCT of extremities, cervical spine, ears and paranasal sinuses was found to be a low-dose volumetric imaging technique. Effective doses varied significantly because of different exposure settings of CBCT-units and different dosimetry systems used to estimate dose.

Swallowing impairment in neurologic disorders: the role of videofluorographic swallowing study.

Patients with neurologic diseases almost inevitably develop various degrees of swallowing disorders during their life. Dysphagia is one of the main negative prognostic factors in this class of patients, leading to severe morbidity (i.e. aspiration pneumonia, dehydration, malnutrition, and life quality deterioration) and to a noticeable increase in public health spending. Videofluorographic swallowing study is considered the gold standard technique for swallowing impairment assessment. It is aimed at early identification of the risk of aspiration, definition of the kind and grade of dysphagia, and an indication to suspend oral nutrition and adopt other feeding strategies, and define when the patient is able to return to physiological nutrition. Every radiologist should be familiar with the main videofluorographic swallowing features in neurological patients, not only because early diagnosis of deglutition disorders widely improves their prognosis, but also because customising feeding strategies has a great impact on patients' quality of life.

Umbilical venous catheters placement evaluation on frontal radiogram: application of a simplified flow-chart for radiology residents.

BACKGROUND: Umbilical Venous Catheter (UVC) are commonly used in neonatal period; they can be not correctly positioned and could be associated with complications. The purpose of this article is to suggest a flow-chart to evaluate the placement of UVC, testing it in young radiologists-in-training. METHOD: We developed a simple flow-chart to asses, steps by step, UVC placement considering its course and tip location (ideally placed in the atriocaval junction). We tested the flow-chart impact asking to 20 residents to evaluate the placement of 10 UVC before and after they familiarized with the flow-chart and the anatomical findings of a newborn. The agreement among the 20 students was evaluated too. RESULTS: The number of correct characterizations was different due to the administration of the flow-chart. One hundred and six correct UVC assessments at the beginning switched to 196 after the administration of the flow-chart (p = 0.0001). The observed agreement among the twenty radiology residents was statistically significant, both before (kappa = 0.41, p < 0.001) and after (kappa = 0.37, p < 0.001) the flow-chart administration. CONCLUSION: The developed flow-chart demonstrated to be useful in increasing residents performance in UVC placement assessment.

The burnout phenomenon among student radiographers: a single centre experience.

OBJECTIVES: Burnout syndrome is a condition that may occur not only for staff in human service sectors/jobs, involving intensive interactions with others, but also people that are engaged in activities psychologically similar to work, such as students. Radiographers in training suffer double stress, first linked to the status of being a university student and secondly as early career workers who have relations with the public of the health system. Aim of our study was to investigate the prevalence and levels of burnout syndrome among radiographers in training in an University Hospital. METHODS: In order to gain a better understanding of nature of the burnout syndrome a modified version of Maslach's questionnaire (investigating three areas: emotional exhaustion, depersonalization and reduced personal accomplishment), was administered to two groups selected from a cohort of radiographers University students (from the 1st and 3rd year of course). RESULTS: 62/62 questionnaires were completed, returned and analysed. The research outcomes highlighted a clear difference between group I and group II in relation to one of the three areas of the Maslach's model: "depersonalization" (p<0.001). Moreover, the third year students group presented a significantly higher risk to develop burnout. On the other hand, the third area examined, the reduced personal accomplishment domain, was surprisingly high even among first-year students. CONCLUSIONS: The research outcomes seem to suggest that the presence of emotional burnout, or risk of burnout, among third year students is statistically significant, compared to the first year students, being a significant aspect to investigate further in this class of students. It is also assumed that the high degree of "past failures, feeling of self failure" observed among all student, is related to a feeling of poor efficacy and poor self worth that appear to grow from the beginning of the course. This topic needs further investigation in the light of the result of this study.

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

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

MR imaging of perianal fistulas in Crohn's disease: sensitivity and specificity of STIR sequences.

INTRODUCTION: Although some studies proved the role of STIR sequences in the evaluation of perianal fistulas in Crohn's Disease (CD), contrast medium is still injected in many institutions since there is not a validated reference MR protocol. Our purpose was to evaluate the role of the STIR sequence in the detection and characterization of perianal fistulae comparing it to the post-contrast T1 sequence and correlating it with rectal examination under anesthesia. MATERIALS AND METHODS: We retrospectively reviewed all clinical records of 31 CD patients, suspected of having perianal fistulas, who had been submitted to an MR study before and after contrast medium injection and surgical exploration under anesthesia within the same month. Perianal fistulas were classified according to the Parks' criteria. Finally, comparison between STIR and post-contrast T1-weighted fat saturated sequences was done. RESULTS: 29 fistulas were detected in 25 patients who underwent an MR study. There was no significant difference between MR imaging and exploration under anesthesia. For the detection of perianal fistulas of any type, there was a perfect statistical agreement between gadolinium-enhanced and STIR sequences (kappa value = 1). CONCLUSION: STIR sequences represent a valid alternative to the T1-weighted sequences acquired after the injection of contrast medium, allowing the identification of the primary fistula, any secondary ramification, and complications of the disease.

Relationship between anxiety level and radiological investigation. Comparison among different diagnostic imaging exams in a prospective single-center study.

OBJECTIVE: Every patient could feel anxious when he waits in a radiological department to undergo diagnostic exams. The aim of our study is to evaluate the impact of the radiological exams on patient anxiety. MATERIALS AND METHODS: We evaluated 343 patients (mean age 54.83 years) who underwent different types of diagnostic exams in the Department of Diagnostic Imaging at our Hospital from April 2013 to August 2014. We administered to patients the State and Trait Anxiety Inventory Test, which detected with high sensitivity both state anxiety and trait anxiety. A team of clinical psychologists and radiologists evaluated the scores obtained. RESULTS: 83 out of 343 patients were excluded because refused to file the questionnaire. 31 % of the patients were submitted to MR, 18 % to breast imaging, 10 % to X-ray, 22 % Computer Tomography and 19 % to ultrasound, as previously described. 41 % of patients were submitted to the examination because of an oncologic disease, while 59 % because of non-oncological disease. Therefore, it was found that high levels of anxiety were present in most (about 91 %) of the patients and the scores varied according to the imaging examination and to the examination's reason: anxiety level was higher in non-oncological patients (54 %) and in patients waiting to undergo to MRI exams (29 %). CONCLUSION: Our data suggest that the diagnostic exams are stressful events for the patient, also in non-oncological patients. So, it is important to adequate the radiological staff to receive the patient, to inform him and perform exams with emotive involvement with a targeted education. Also, further studies are needed to evaluate the anxiety level and the quality of the images, because the anxiety can result in a somatic disorder with hyperactivity of the autonomic nervous system which may affect the patient's physical examination, causing problems in the evaluation of radiological images making to non-cooperative patient. MRI imaging is the examination that more of all led to an anxious state of patients but the main stressor is not related to the type of diagnostic examination, but to the uncertainty of the diagnosis, therapy and prognosis.

Radiation dose from multidetector CT studies in children: results from the first Italian nationwide survey.

BACKGROUND: Multidetector CT (MDCT) scanners have contributed to the widespread use of CT in paediatric imaging. However, concerns are raised for the associated radiation exposure. Very few surveys on radiation exposure from MDCT studies in children are available. OBJECTIVE: The aim of this study was to outline the status of radiation exposure in children from MDCT practice in Italy. MATERIALS AND METHODS: In this retrospective multicentre study we asked Italian radiology units with an MDCT scanner with at least 16 slices to provide dosimetric and acquisition parameters of CT examinations in three age groups (1-5, 6-10, 11-15 years) for studies of head, chest and abdomen. The dosimetric results were reported in terms of third-quartile volumetric CT dose index (CTDIvol) (mGy), size-specific dose estimate (SSDE) (mGy), dose length product (DLP) (mGy cm), and total DLP for multiphase studies. These results were compared with paediatric European and adult Italian published data. A multivariate analysis assessed the association of CTDIvol with patient characteristics and scanning modalities. RESULTS: We collected data from 993 MDCT examinations performed at 25 centres. For age groups 1-5 years, 6-10 years and 11-15 years, the CTDIvol, DLP and total DLP values were statistically significantly below the values observed in our analogous national survey in adults, although the difference decreased with increasing age. CTDIvol variability among centres was statistically significant (variance = 0.07; 95% confidence interval = 0.03-0.16; P < 0.001). CONCLUSIONS: This study reviewed practice in Italian centres performing paediatric imaging with MDCT scanners. The variability of doses among centres suggests that the use of standardised CT protocols should be encouraged.

Role of virtopsy in the post-mortem diagnosis of drowning.

PURPOSE: Due to admitted limits of autopsy-based studies in the diagnosis of drowning, virtopsy is considered the new imaging horizon in these post-mortem studies. The aim of our study was to evaluate the role of virtopsy performed through computed tomography (CT) in the forensic diagnosis of drowning. MATERIALS AND METHODS: We retrospectively examined the CT data of four cadavers recovered from sea water and suspected to have died by drowning. Each patient underwent a full-body post-mortem CT scan, and then a traditional autopsy. RESULTS: All the cadavers showed fluid in the airways and patchy ground-glass opacities in the lung. Only one patient had no fluid in the digestive tract; this patient had a left parietal bone fracture with a large gap and other multiple bone fractures (nose, clavicle, first rib and patella). One of the three patients who had fluid in the digestive tract had no fluid in the paranasal sinuses. This latter patient showed cerebral oedema with subarachnoid and intraventricular haemorrhage, multiple bone fractures (orbital floor, ribs, sacrum and acetabular edge) and air in the heart, in the aorta and in bowel loops. CONCLUSION: To date, there are no autopsy findings pathognomonic of drowning. This study proves that virtopsy is a useful tool in the diagnosis of drowning in that it allows us to understand if the victim was alive or dead when he entered the water and if the cause of death was drowning.

Adult exposures from MDCT including multiphase studies: first Italian nationwide survey.

OBJECTIVES: To evaluate the radiation dose in routine multidetector computed tomography (MDCT) examinations in Italian population. METHODS: This was a retrospective multicentre study included 5,668 patients from 65 radiology departments who had undergone common CT protocols: head, chest, abdomen, chest­abdomen­pelvis (CAP), spine and cardiac. Data included patient characteristics, CT parameters, volumetric CT dose index (CTDIvol) and dose length product (DLP) for each CT acquisition phase. Descriptive statistics were calculated, and a multi-regression analysis was used to outline the main factors affecting exposure. RESULTS: The 75th percentiles of CTDIvol (mGy) and DLP (mGy cm) for whole head were 69 mGy and 1,312 mGy cm, respectively; for chest, 15 mGy and 569 mGy cm; spine, 42 mGy and 888 mGy cm; cardiac, 7 mGy and 131 mGy cm for calcium score, and 61 mGy and 1,208 mGy cm for angiographic CT studies. High variability was present in the DLP of abdomen and CAP protocols, where multiphase examinations dominated (71 % and 73 % respectively): for abdomen, 18 mGy, with 555 and 920 mGy cm in abdomen and abdomen­pelvis acquisitions respectively; for CAP, 17 mGy, with 508, 850 and 1,200 mGy cm in abdomen, abdomen­pelvis and CAP acquisitions respectively. CONCLUSION: The results of this survey could help in the definition of updated diagnostic reference levels (DRL). KEY POINTS: • Radiation dose associated with multidetector CT (MDCT) is an important health issue. • This national survey assessed dose exposures of 5,668 patients undergoing MDCT. • Dose indices correlate with BMI, voltage, rotation time, pitch and tube current. • These results may contribute to an update of national diagnostic reference levels.