Estimated radiation risks potentially associated with full-body CT screening

Risk of Malignancy in Incidentally Detected Lung Nodules in Patients Aged Younger Than 35 Years

BACKGROUND

The risk of malignancy in pulmonary nodules incidentally detected on computed tomography (CT) in patients who are aged younger than 35 years is unclear.

OBJECTIVE

The aim of this study was to evaluate the incidence of lung cancer in incidental pulmonary nodules in patients who are 15-34 years old.

METHODS

This retrospective study included patients aged 15-34 years who had an incidental pulmonary nodule on chest CT from 2010 to 2018 at our hospital. Patients with prior, current, or suspected malignancy were excluded. A chart review identified patients with diagnosis of malignancy. Incidental pulmonary nodule was deemed benign if stable or resolved on a follow-up CT at least 2 years after initial or if there was a medical visit in our health care network at least 2 years after initial CT without diagnosis of malignancy.Receiver operating characteristic curve analysis was performed with nodule size. Association of categorical variables with lung cancer diagnosis was performed with Fisher exact test, and association of continuous variables was performed with logistic regression.

RESULTS

Five thousand three hundred fifty-five chest CTs performed on patients aged 15-34 years between January 2010 and December 2018. After excluding patients without a reported pulmonary nodule and prior or current malignancy, there were a total of 779 patients. Of these, 690 (89%) had clinical or imaging follow-up after initial imaging. Of these, 545 (70% of total patients) patients had imaging or clinical follow-up greater than 2 years after their initial imaging.A malignant diagnosis was established in 2/779 patients (0.3%; 95% confidence interval, 0.1%-0.9%). Nodule size was strongly associated with malignancy ( P = 0.007), with area under the receiver operating characteristic curve of 0.97. There were no malignant nodules that were less than 10 mm in size. Smoking history, number of nodules, and nodule density were not associated with malignancy.

CONCLUSIONS

Risk of malignancy for incidentally detected pulmonary nodules in patients aged 15-34 years is extremely small (0.3%). There were no malignant nodules that were less than 10 mm in size. Routine follow-up of subcentimeter pulmonary nodules should be carefully weighed against the risks.

Deep Learning Image Reconstruction for Transcatheter Aortic Valve Implantation Planning: Image Quality, Diagnostic Performance, Contrast volume and Radiation Dose Assessment

RATIONALE AND OBJECTIVES

To assess image quality, contrast volume and radiation dose reduction potential and diagnostic performance with the use of high-strength deep learning image reconstruction (DLIR-H) in transcatheter aortic valve implantation (TAVI) planning CT.

METHODS

We prospectively enrolled 128 patients referred to TAVI-planning CT. Patients were randomly divided into two groups: DLIR-H group (n = 64) and conventional group (n = 64). The DLIR-H group was scanned with tube voltage of 80kVp and body weighted-dependent contrast injection rate of 28mgI/kg/s, images reconstructed using DLIR-H; the conventional group was scanned with 100kVp and contrast injection rate of 40mgI/kg/s, and images reconstructed using adaptive statistical iterative reconstruction-V at 50% (ASIR-V 50%). Radiation dose, contrast volume, contrast injection rate, and image quality were compared between the two groups. The diagnostic performance of TAVI planning CT for coronary stenosis in 115 patients were calculated using invasive coronary angiography as golden standard.

RESULTS

DLIR-H group significantly reduced radiation dose (4.94 ± 0.39mSv vs. 7.93 ± 1.20mSv, p < 0.001), contrast dose (45.28 ± 5.38 mL vs. 63.26 ± 9.88 mL, p < 0.001), and contrast injection rate (3.1 ± 0.31 mL/s vs. 4.9 ± 0.2 mL/s, p < 0.001) compared to the conventional group. Images in DLIR-H group had significantly higher SNR and CNR (all p < 0.001). For the diagnostic performance on a per-patient basis, TAVI planning CT in the DLIR-H group provided 100% sensitivity, 92.1% specificity, 100% negative predictive value (NPV), and 84.2% positive predictive value for the detection of > 50% stenosis. In the conventional group, the corresponding results were 94.7%, 95.3%, 97.6%, and 90.0%, respectively.

CONCLUSION

DLIR-H in TAVI-planning CT provides improved image quality with reduced radiation and contrast doses, and enables satisfactory diagnostic performance for coronary arteries stenosis.

Integrating Artificial Intelligence for Advancing Multiple-Cancer Early Detection via Serum Biomarkers: A Narrative Review

The concept and policies of multicancer early detection (MCED) have gained significant attention from governments worldwide in recent years. In the era of burgeoning artificial intelligence (AI) technology, the integration of MCED with AI has become a prevailing trend, giving rise to a plethora of MCED AI products. However, due to the heterogeneity of both the detection targets and the AI technologies, the overall diversity of MCED AI products remains considerable. The types of detection targets encompass protein biomarkers, cell-free DNA, or combinations of these biomarkers. In the development of AI models, different model training approaches are employed, including datasets of case-control studies or real-world cancer screening datasets. Various validation techniques, such as cross-validation, location-wise validation, and time-wise validation, are used. All of the factors show significant impacts on the predictive efficacy of MCED AIs. After the completion of AI model development, deploying the MCED AIs in clinical practice presents numerous challenges, including presenting the predictive reports, identifying the potential locations and types of tumors, and addressing cancer-related information, such as clinical follow-up and treatment. This study reviews several mature MCED AI products currently available in the market, detecting their composing factors from serum biomarker detection, MCED AI training/validation, and the clinical application. This review illuminates the challenges encountered by existing MCED AI products across these stages, offering insights into the continued development and obstacles within the field of MCED AI.

Can the use of whole-body CT be reduced in cases of kinetic-based polytrauma patients without a clinical severity criterion? A bi-center retrospective study

OBJECTIVE

To identify clinical and biological criteria predictive of significant traumatic injury in only kinetic-based polytrauma patients without clinical severity criteria. To propose a decisional algorithm to assist the emergency doctor in deciding whether or not to perform a WBCT in the above population.

METHODS

Retrospective bi-center study. 1270 patients with high velocity trauma without clinical severity criteria, for whom a WBCT was performed in 2017, were included. Patients with hemodynamic, respiratory or neurological severity criterion or those requiring pre-hospital resuscitation measures were excluded. Our primary endpoint was the identification of a significant lesion, i.e. any lesion that led to hospitalization > 24 h for monitoring or medico-surgical treatment. Data collected were age, sex, mechanism of injury, Glasgow Coma Scale score, number of symptomatic body regions, blood alcohol level, and neutrophil count.

RESULTS

Multivariate analysis found independent predictors of significant injury: fall > 5 m (OR: 14.36; CI: 2.3-283.4; p = 0.017), Glasgow score = 13 or 14 (OR: 4.40; CI:1.30-18.52; p = 0.027), presence of 2 symptomatic body regions (OR: 10.21; CI: 4.66-23.72; p = 0.05), positive blood alcohol level (OR: 2.81; CI: 1.13-7.33; p = 0.029) and neutrophilic leukocytosis (OR: 8.76; CI: 3.94-21.27; p = 0.01). A composite clinico-biological endpoint predictive of the absence of significant lesion was identified using a Classification and Regression Tree: number of symptomatic regions < 2, absence of Neutrophilic leukocytosis and negative blood alcohol concentration.

CONCLUSION

A simple triage algorithm was created with the objective of identifying, in high velocity trauma without clinical severity criteria, those without significant traumatic injury.

Prognostic impact of early aortic volume changes at hospital discharge in patients with acute type B aortic dissection

BACKGROUND

Early prediction of aorta-related events is important for determining subsequent treatment strategies in patients with acute aortic dissection. However, most studies evaluated long-term aortic growth rates by annual assessment. The purpose of our study was to determine whether the in-hospital growth rate of aortic volume was associated with aorta-related events.

METHODS

We studied 116 patients with uncomplicated type B acute aortic dissection. We analyzed whether changes in aortic volume were associated with aorta-related events during a 5-year follow-up. According to the growth rate from admission to discharge, patients were divided into two groups: Increase >0 (aortic volume: n = 59, aortic diameter: n = 43) and Reduction ≤0 (aortic volume: n = 57, aortic diameter: n = 73) in maximum aortic diameter or aortic volume. The primary endpoint was the discriminative ability of the growth rate of aortic volume for aorta-related events.

RESULTS

According to the evaluation of aortic volume changes, the Increase group had significantly higher aorta-related event rates than those in the Reduction group (49.2 % vs. 3.5 %, respectively; p < 0.001). Receiver operating characteristics analysis showed that the growth rate of aortic volume had a clearly useful discrimination, with an area under the curve of 0.84, whereas the discriminative ability of the growth rate of maximum aortic diameter was poor (area under the curve: 0.53). Multivariate analysis showed that the growth rate of aortic volume from admission to discharge was an independent predictor of aorta-related events (hazard ratio, 26.3; 95 % confidence interval, 2.04-286.49; p = 0.001).

CONCLUSIONS

In-hospital evaluation of aortic volume was helpful to predict long-term aorta-related events in patients with uncomplicated type B acute aortic dissection.

Review of Clinical Applications of Dual-Energy CT in Patients after Endovascular Aortic Repair

Abdominal aortic aneurysms (AAAs) are a significant cause of mortality in developed countries. Endovascular aneurysm repair (EVAR) is currently the leading treatment method for AAAs. Due to the high sensitivity and specificity of post-EVAR complication detection, CT angiography (CTA) is the reference method for imaging surveillance in patients after EVAR. Many studies have shown the advantages of dual-energy CT (DECT) over standard polyenergetic CTA in vascular applications. In this article, the authors briefly discuss the technical principles and summarize the current body of literature regarding dual-energy computed tomography angiography (DECTA) in patients after EVAR. The authors point out the most useful applications of DECTA in this group of patients and its advantages over conventional CTA. To conduct this review, a search was performed using the PubMed, Google Scholar, and Web of Science databases.

[18F]FDG PET/MRI in children suffering from lymphoma: does MRI contrast media make a difference?

OBJECTIVES

Evaluate the influence of an MRI contrast agent application on primary and follow-up staging in pediatric patients with newly diagnosed lymphoma using [18F]FDG PET/MRI to avoid adverse effects and save time and costs during examination.

METHODS

A total of 105 [18F]FDG PET/MRI datasets were included for data evaluation. Two different reading protocols were analyzed by two experienced readers in consensus, including for PET/MRI-1 reading protocol unenhanced T2w and/or T1w imaging, diffusion-weighted imaging (DWI), and [18F]FDG PET imaging and for PET/MRI-2 reading protocol an additional T1w post contrast imaging. Patient-based and region-based evaluation according to the revised International Pediatric Non-Hodgkin's Lymphoma (NHL) Staging System (IPNHLSS) was performed, and a modified standard of reference was applied comprising histopathology and previous and follow-up cross-sectional imaging. Differences in staging accuracy were assessed using the Wilcoxon and McNemar tests.

RESULTS

In patient-based analysis, PET/MRI-1 and PET/MRI-2 both determined a correct IPNHLSS tumor stage in 90/105 (86%) exams. Region-based analysis correctly identified 119/127 (94%) lymphoma-affected regions. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for PET/MRI-1 and PET/MRI-2 were 94%, 97%, 90%, 99%, 97%, respectively. There were no significant differences between PET/MRI-1 and PET/MRI-2.

CONCLUSIONS

The use of MRI contrast agents in [18F]FDG PET/MRI examinations has no beneficial effect in primary and follow-up staging of pediatric lymphoma patients. Therefore, switching to a contrast agent-free [18F]FDG PET/MRI protocol should be considered in all pediatric lymphoma patients.

CLINICAL RELEVANCE STATEMENT

This study gives a scientific baseline switching to a contrast agent-free [18F]FDG PET/MRI staging in pediatric lymphoma patients. This could avoid side effects of contrast agents and saves time and costs by a faster staging protocol for pediatric patients.

KEY POINTS

• No additional diagnostic benefit of MRI contrast agents at [18F]FDG PET/MRI examinations of pediatric lymphoma primary and follow-up staging • Highly accurate primary and follow-up staging of pediatric lymphoma patients at MRI contrast-free [18F]FDG PET/MRI.

Effect of cumulative radiation exposure from Coronary catheterization on lung cancer mortality

BACKGROUND

Coronary catheterization (CC) procedure inevitably exposes patients with cardiovascular disease (CVD) to radiation, while cumulative radiation exposure may lead to higher risk of cancer.

METHODS

This multi-center, retrospective study was based on the CC procedure in Cardiorenal ImprovemeNt II cohort (CIN-II, NCT05050877) among five regional central tertiary teaching hospitals in China between 2007 and 2020. Patients without known cancer were stratified according to the times they received CC procedure. Baseline information from their last CC procedure was analyzed. Cox regression and Fine-Gray competing risk models were used to assess the relationship between cumulative radiation exposure from CC procedures and cancer-specific, all-cause and cardiovascular mortality.

RESULTS

Of 136,495 hospitalized survivors without cancer at baseline (mean age: 62.3 ± 11.1 years, 30.9% female), 116,992 patients (85.7%) underwent CC procedure once, 15,184 patients (11.1%) on twice, and 4,319 patients (3.2%) underwent CC procedure more than three times. During the median follow-up of 4.7 years (IQR: 2.5 to 7.4), totally 18,656 patients (13.7%) died after discharge, of which 617 (0.5%) died of lung cancer. Compared with the patients who underwent CC procedure once, the risk of lung cancer mortality increased significantly with the increase of the number of CC procedure (CC 2 times vs. 1 time: HR 1.42, 95% CI 1.13 to 1.78, P < 0.001; CC ≥ 3 times vs. 1 time: HR 1.64, 95%CI 1.13 to 2.39, P < 0.05). Similar results were observed in all-cause mortality and cardiovascular mortality, but not in other cancer-specific mortality.

CONCLUSIONS

Our data suggest that substantial proportion of CVD patients are exposed to multiple high levels of low-dose ionizing radiation from CC procedure, which is associated with an increased risk of cancer mortality in this population.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05050877; URL: http://www.

CLINICALTRIALS

gov ; 21/09/2021.

CANCER RISK ESTIMATION FOR PATIENTS UNDERGOING WHOLE-BODY PET/CT SCANS

The objective of this paper was to compute the effective dose, as well as the lifetime attributable risk (LAR) of cancer related to whole-body positron emission tomography (PET)/computed tomography (CT) scan for 193 adult patients. The mean effective dose for all patients from a single PET/CT scan was 20.6 mSv. For males aged 40 y, a single PET/CT scan is associated with a LAR of cancer incidence of 0.169%. This risk increased to 0.85% if an annual surveillance protocol for 5 y was performed. For female patients aged 40 y, the LAR of cancer mortality increased from 0.126 to 0.63% if an annual surveillance protocol for 5 y was performed. Since PET/CT scans are associated with a high dose and a risk of developing cancer, it was important to balance the advantages and risks before conducting any scans. This is especially important for younger patients and those who are overweight.

Implementation of a Magnetic Resonance Imaging scanner dedicated to emergencies in cases of binocular diplopia: Impact on patient management

RATIONALE AND OBJECTIVES

Evaluate the implementation of an MRI scanner dedicated to emergencies on the management of patients admitted in the emergency department (ED) for binocular diplopia (BD).

MATERIAL AND METHODS

This was a prospective non-interventional single-center study from February 2018 to February 2020. A total of 110 patients were included: 52 patients during the first stage (29 women; 23 men; mean age 65.2 years); 58 during the second stage (29 women; 29 men; mean age 51.4 years). Patients underwent an enhanced-CT examination in the first stage and an MRI examination in the second stage. Criteria used to evaluate the new management of patients were: proportion of patients with an imaging diagnosis explaining BD, turnaround time (TT), ED length of stay (EDLOS), hospital admission rate, hospital length of stay (HLOS), number of MRI examinations requested as a second procedure for the same indication and radiation doses. Descriptive statistics were used to present results with Student's test for quantitative variables and chi-square test for qualitative variables.

RESULTS

Respectively 1 (1.92%) and 17 (29.31%) patients had definitive diagnosis in stages 1 and 2, with a significant difference in examination modalities (p=0.0001). The TT, EDLOS, hospital admission rate, and HLOS were not significantly different between the two stages. Radiation dose was significantly different between the two groups (p<0.05).

CONCLUSION

Implementation of an MRI scanner dedicated to emergencies can improve the etiological diagnostic performance of binocular diplopia and reduce patient's exposure to ionizing radiation without increasing the average turnaround time or emergency department length of stay.

ESTIMATION OF PATIENT ORGAN AND WHOLE-BODY DOSES IN [18F-FDG] PET/CT SCAN

The object of this study was to estimate organ doses and whole-body effective doses from positron emission tomography/computed tomography (PET/CT) scan using [fluorine-18]-fluoro-2-deoxy-d-glucose (18F-FDG) in adult patients and to assess the CT component contribution to organ and whole-body doses. The [18F-FDG] PET/CT scan was conducted on 204 adult patients (90 females and 114 males). For all patients, females and males, the whole-body effective doses were 20.54, 23.89 and 17.89 mSv, respectively. For all patients, females and males, the CT component contribution to the whole-body effective dose was 66, 71 and 62%, respectively. Since CT is the primary contributor to the effective dose in the [18F-FDG] PET/CT scan protocol, the significance of improving CT protocols to minimize patient dose is underscored. All attempts must be made, using available mechanisms and techniques, to reduce the patient's dose of PET/CT scan, especially in obese patients.

Classification of Skull Shape Deformities Related to Craniosynostosis on 3D Photogrammetry

Implementation of the Utrecht Cranial Shape Quantificator (UCSQ) classification method on 3D photogrammetry in patients with different types of craniosynostosis is the aim of the present study. Five children (age <1 year) of every group of the common craniosynostoses (scaphocephaly, brachycephaly, trigonocephaly, right-sided and left-sided anterior plagiocephaly) were randomly included. The program 3-Matic (v13.0) was used to import and analyze the included 3dMD photos. Three external landmarks were placed. Using the landmarks, a base plane was created, as well as a plane 4 cm superior to the base plane. Using UCSQ, we created sinusoid curves of the patients, the resulting curves were analyzed and values were extracted for calculations. Results per patient were run through a diagnostic flowchart in order to determine correctness of the flowchart when using 3D photogrammetry. Each of the patients (n=25) of the different craniosynostosis subgroups is diagnosed correctly based on the different steps in the flowchart. This study proposes and implements a diagnostic approach of craniosynostosis based on 3D photogrammetry. By using a diagnostic flowchart based on specific characteristics for every type of craniosynostosis related to specific skull deformities, diagnosis can be established. All variables are expressed in number and are therefore objective.

Proposal to Improve the Image Quality of Short-Acquisition Time-Dedicated Breast Positron Emission Tomography Using the Pix2pix Generative Adversarial Network

This study aimed to evaluate the ability of the pix2pix generative adversarial network (GAN) to improve the image quality of low-count dedicated breast positron emission tomography (dbPET). Pairs of full- and low-count dbPET images were collected from 49 breasts. An image synthesis model was constructed using pix2pix GAN for each acquisition time with training (3776 pairs from 16 breasts) and validation data (1652 pairs from 7 breasts). Test data included dbPET images synthesized by our model from 26 breasts with short acquisition times. Two breast radiologists visually compared the overall image quality of the original and synthesized images derived from the short-acquisition time data (scores of 1−5). Further quantitative evaluation was performed using a peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). In the visual evaluation, both readers revealed an average score of >3 for all images. The quantitative evaluation revealed significantly higher SSIM (p < 0.01) and PSNR (p < 0.01) for 26 s synthetic images and higher PSNR for 52 s images (p < 0.01) than for the original images. Our model improved the quality of low-count time dbPET synthetic images, with a more significant effect on images with lower counts.

Estimation of lifetime attributable risk incidence and mortality for breast cancer attributed to computed tomography of the head in the Niger Delta Region of Nigeria

Background

The rising increase in the incidence of breast cancer among women is worrisome and a great concern to all. More disturbing is that the incidence of breast cancer and death has been attributed to exposure to imaging modalities that utilize ionizing radiation such as computed tomography. The aim of this study was to estimate the lifetime attributable risk (LAR) incidence and mortality for breast cancer for female patients who had head computed tomography in two imaging facilities (centres) in the Niger Delta region of Nigeria.

Result

The overall estimated mean effective dose in centres G1 and G2 is 5.76 mSv and 1.54 mSv, respectively. There was a statistical significant difference in the mean effective dose between centres G1 and G2 (P < 0.001). The LAR breast cancer incidence obtained in this study ranged between 0.5 and 26.45 per 100,000 population in centre G1, while in centre G2, it ranged between 0.14 and 6.56 per 100,000 population. The LAR breast cancer mortality obtained in this study ranged between 0.07 and 6.25 per 100,000 population in centre G1, while in centre G2, it ranged between 0.03 and 1.55 per 100,000 population.

Conclusion

The estimated mean LAR of breast cancer incidence and mortality for the women who had head CT examination in the two study centres was found to be minimal to negligible among the female patients of the different age groups in the study population. The overall mean risk of breast cancer incidence was very low in centre G1 and minimal in centre G2. The obtained risk values can be used to optimize the dose delivered to patients and also ensure that CT examinations are justified.

The role of magnetic resonance imaging in acute abdominal pain in paediatric age group

Background

The purpose of this study is to evaluate the utility of magnetic resonance imaging in the assessment of acute atraumatic abdominal pain as the first line cross sectional modality in children, so as to prevent excessive radiation exposure from computed tomography scan and to review the magnetic resonance imaging features of common acute abdominal and pelvic conditions.

Results

30 patients (0–18 years) underwent rapid unenhanced magnetic resonance imaging. The results of our study indicated that for the diagnosis of causes for acute abdominal pain, magnetic resonance imaging had sensitivity of 92% (95% confidence interval 73.8–97.6%) and a specificity of 80% (95% confidence interval 28.4–99.5%). The positive predictive value was 95.8% (95% confidence interval 79.9–99.3%) and negative predictive value was 67% (95% confidence interval 33.1–89.0%) which had a highly significant statistical association (p < 0.001).

Conclusion

Unenhanced magnetic resonance imaging is an excellent option for the initial, detailed evaluation of acute abdominal emergencies in pediatric patients because it can diagnose the whole range of presenting abnormalities which include the causes of abdominal pain warranting surgical and nonsurgical management.

PSMA PET-CT in the Diagnosis and Staging of Prostate Cancer

Prostate cancer is the most common cancer and the second leading cause of cancer death in men. The imaging assessment and treatment of prostate cancer has vastly improved over the past decade. The introduction of PSMA PET-CT has improved the detection of loco-regional and metastatic disease. PSMA PET-CT also has a role in the primary diagnosis and staging, in detecting biochemical recurrence after curative treatment and in metastasis-directed therapy. In this paper we review the role of PSMA PET-CT in prostate cancer.

AUTOMATED ESTIMATION OF PATIENT'S SIZE USING AUTOWED TOOL AND INDOSECT PROGRAM: A DOSIMETRIC STUDY FOR PAEDIATRIC HEAD CT EXAMINATIONS

Size-specific dose estimate (SSDE), which can be calculated by measuring the effective diameter (De) or water equivalent diameter (Dw) of the patient, is one of the recent approaches for verifying the individual doses during computer tomography (CT) examinations. This work aimed to compare the Dw estimated by the AutoWED tool and IndoseCT software and to investigate CT axial (ARH) and paediatric head (PH) protocols used in southern Saudi Arabia to calculate the dose received by paediatric patients using metrics of volume CT dose index (CTDIvol) and SSDE. The distribution between the ARH and PH protocols was 57.8 and 42.2%, respectively. There was no significant difference in Dw values between the AutoWED tool and the IndoseCT program (0.13%). Including CT table or other objects during estimation of Dw can lead to variation up to 11.4%. The impact of selecting IndoseCT options to identify the border of the patient may be part of the explanation for these variations. A strong linear relationship was obtained between De and Dw in paediatric head size (R2 = 0.96). Using IndoseCT, for 0-1.5, 1.5-5 and 5.0-18 age groups (years), the Dw was found to be 13.2, 15.3 and 16.8 cm, respectively. The SSDE for the PH protocol was substantially lower than that of the ARH protocol. As a result, education of the individuals engaging in paediatric CT examinations is necessary for dose optimization.

Improving the protocol for whole-body CT scans in trauma patients

PURPOSE

While whole-body computed tomography is an established diagnostic method for the work up of polytraumatized patients, the protocols used differ between trauma centers. This study aimed to compare scan duration and estimated radiation of two protocols. Secondary aim was to assess if using the revised CT protocol reduced the number of additional images of the upper extremities.

METHODS

Two groups of consecutive trauma patients, which both received a whole-body CT, were analyzed. Patients, who received a three-phased CT during which their arms needed to be repositioned from their side to above the head, were assigned to group A. Those, who received a CT with their arms placed on a pillow ventral to the abdomen throughout the entire scan were assigned to group B. Estimated radiation dose, scan duration, number of upper limb injuries and number of additional images of the upper limbs within 24 h after initial CT were assessed.

RESULTS

Group A consisted of 182 patients, group B of 218. The scan duration was 3 min shorter (p < 0.001) and the estimated radiation dose lower (15.0 vs 22.9 mSv, p < 0.001) in group B. There was no difference in the number of upper limb injuries detected or the number of upper limb additional images required within 24 h.

CONCLUSION

Using a whole-body CT scan protocol in which the arms remain on a pillow ventral to the torso instead of one which requires a repositioning of the arms, both scan duration and estimated radiation dose can be reduced. Despite the arms being within the scanned area in the revised protocol, the number of additional imaging of the upper extremities could not be reduced.

Feasibility Study of Dose Modulation for Reducing Radiation Dose with Arms-Down Patient Position in Abdominal Computed Tomography

This study was carried out to demonstrate whether the radiation dose for patients in arms-down position can be reduced without affecting the diagnosis on abdominal computed tomography (CT). The patients were divided into two groups: group A, which included patients with arms-down position using dose modulation on, and group B, which included patients with arms-down position using dose modulation turned off. Quantitative evaluation was compared using Hounsfield units, standard deviation, and signal-to-noise ratio of the four regions. The qualitative evaluation was assessed for overall image quality, subjective image noise, and beam hardening artifacts. Dose evaluation for CT dose index (CTDI) and dose length product (DLP) was compared by comparing the CT images with dose modulation turned on and off. In the quantitative and qualitative evaluation, there was no statistically significant difference between groups A and B (p > 0.05). In the dose evaluation, the CT images with dose modulation turned off had significantly lower CTDI and DLP than the CT images with dose modulation turned on (p < 0.05). Our results suggest that, for the GE Revolution EVO CT scanner, turning off dose modulation and increasing the tube voltage can reduce the radiation dose for patients with the arms-down position without affecting the diagnosis. This study did not consider the change of tube potential according to the use of dose modulation, and we plan to conduct additional research in the future.

Head CT dose reduction with organ-based tube current modulation

BACKGROUND

A helical head CT examination uses a pitch factor (PF) of < 1.0, resulting in a part of the slice being directly irradiated twice. This raises the possibility of double irradiation, which may increase the amount of radiation to the lens. Organ-based tube current modulation (OBTCM) is an effective method for reducing lens exposure because it reduces the dose to the anterior aspect of the patient. However, it is challenging to visualize the complex dose distribution when factoring in double irradiation.

PURPOSE

To visualize twice-irradiated areas in helical head CT in three dimensions and to clarify the exposure reduction effect of OBTCM.

MATERIAL AND METHODS

A leuco crystal violet (LCV) dosimeter was placed into an empty polyethylene terephthalate bottle 16.5 cm in diameter. Helical scans were performed without and with OBTCM using the following parameters: tube voltage 120 kV, tube current 600 mA, pitch factor 0.637, rotation time 0.5 s, 80 (detector rows) × 0.5 mm (detector collimation), and ten scans. Exposed areas were visualized using an optical computed tomography (OCT) system designed by our group. The dose reduction rate of OBTCM was defined as the ratio of the average values of the histogram with the dose value on the x-axis and the frequency on the y-axis without and with OBTCM at 90° to the anterior midline.

RESULTS

The LCV dosimeter visualized the spiral-shaped twice-irradiated areas. Double irradiation resulted in a dose of 2.19/1.90 Gy and 1.38/1.19 Gy (15.0% and 15.9% increase) without and with OBTCM, respectively. The dose reduction using OBTCM was 29.6% at 90° anterolateral.

CONCLUSION

The LCV dosimeter visualized the complex three-dimensional irradiated areas and enabled dose measurement in twice-irradiated areas. Increased exposure from double irradiation was attenuated by OBTCM. This article is protected by copyright. All rights reserved.

Three-dimensional reconstruction of In Vivo human lumbar spine from biplanar radiographs

We present a method for three dimensional (3D) reconstruction of in vivo human lumbar spine from biplanar radiographs with comparable results to Computerised Tomography (CT) scans or Magnetic Resonance Imaging (MRI) models. In this work, we used uncalibrated radiographs to reconstruct the 3D vertebrae and a priori information stored in an Active Shape Model (ASM) that is constructed using the Spherical Demons Algorithm. The method is semi-automatic as bounding boxes are required to delimit the positions of the vertebrae on biplanar radiographs of a patient. Optimisation is based on comparisons between simulated and actual radiographs. Finally, we compare the results to the models generated from MRI and CT scans. The results show the feasibility of generating personalised models of patients from biplanar radiographs.

Contemporary biomedical engineering perspective on volitional evolution for human radiotolerance enhancement beyond low-earth orbit

A primary objective of the National Aeronautics and Space Administration (NASA) is expansion of humankind's presence outside low-Earth orbit, culminating in permanent interplanetary travel and habitation. Having no inherent means of physiological detection or protection against ionizing radiation, humans incur capricious risk when journeying beyond low-Earth orbit for long periods. NASA has made large investments to analyze pathologies from space radiation exposure, emphasizing the importance of characterizing radiation's physiological effects. Because natural evolution would require many generations to confer resistance against space radiation, immediately pragmatic approaches should be considered. Volitional evolution, defined as humans steering their own heredity, may inevitably retrofit the genome to mitigate resultant pathologies from space radiation exposure. Recently, uniquely radioprotective genes have been identified, conferring local or systemic radiotolerance when overexpressed in vitro and in vivo. Aiding in this process, the CRISPR/Cas9 technique is an inexpensive and reproducible instrument capable of making limited additions and deletions to the genome. Although cohorts can be identified and engineered to protect against radiation, alternative and supplemental strategies should be seriously considered. Advanced propulsion and mild synthetic torpor are perhaps the most likely to be integrated. Interfacing artificial intelligence with genetic engineering using predefined boundary conditions may enable the computational modeling of otherwise overly complex biological networks. The ethical context and boundaries of introducing genetically pioneered humans are considered.

Outcome of selective CT vs. pan-CT scan in elderly trauma patients: A retrospective cohort study in a level 1 trauma center

PURPOSE

There are currently no clear guidelines for use of pan- or selective CT in elderly trauma patients and this subject matter remains controversial. The aim of this study is to compare the outcome of elderly trauma patients in a level 1 trauma centre who required a pan- or selective CT scan on admission.

METHODS

The Trauma Audit Research Network database was reviewed to identify eligible patients (≥65 years) over a one-year period, from January 2018 to January 2019. Patients' demographics, mechanism of injury, injury severity score, length of hospital stay (LOS), mortality and type of CT scans done were recorded. The inclusion criteria were elderly patients ≥65 years involved in acute trauma setting (less than one day between incident and emergency department presentation and blunt mechanism of injury). Exclusion criteria were patients <65 years, perforating mechanism of injury and patients with delayed presentation more than one day after the incident, and patients who have not got any CT scan at presentation. Statistical analyses were undertaken on SPSS (version 25.0; IBM, New York, USA).

RESULTS

In total, 481 patients with the mean age of 80.8 years were evaluated (48.6% male). Among them 232 cases were multiple injuries while 249 were single system injuries. And 235 patients (48.8%) underwent pan-CT in whom 66.8% were multiple injuries; 246 (51.1%) did selective CT scan in whom 69.5% were single system injuries. In multiple injury patients, performing a pan-CT scan on presentation was associated with shorter LOS compared to those who had a selective CT, in which 76.4% patients spent < 21 days in the pan-CT group compared to 16.0% for those investigated by selective CT scan (p < 0.001); and 2.5% spent > 60 days in pan-CT group compared to 64% in selective CT group (p < 0.0001). Performing pan-CT was also associated with lower need to repeat CT (p < 0.01). In patients with a single system injury, no differences were found in LOS or the need to repeat CT if either pan-CT or selective CT were requested.

CONCLUSION

We recommend doing pan-CT scan in all elderly patients with multiple system injuries as it decreases the LOS and the need for another CT during hospital stay. No difference in LOS or the need to repeat another CT if pan-CT or selective CT were requested initially in single system injuries. Although age and injury severity score are poor predictors for the need to do pan-CT, the mechanism of injury may be helpful.

Diagnostic performance and image quality of deep learning image reconstruction (DLIR) on unenhanced low-dose abdominal CT for urolithiasis

BACKGROUND

Patients with urolithiasis undergo radiation overexposure from computed tomography (CT) scans. Improvement of image reconstruction is necessary for radiation dose reduction.

PURPOSE

To evaluate a deep learning-based reconstruction algorithm for CT (DLIR) in the detection of urolithiasis at low-dose non-enhanced abdominopelvic CT.

MATERIAL AND METHODS

A total of 75 patients who underwent low-dose abdominopelvic CT for urolithiasis were retrospectively included. Each examination included three reconstructions: DLIR; filtered back projection (FBP); and hybrid iterative reconstruction (IR; ASiR-V 70%). Image quality was subjectively and objectively assessed using attenuation and noise measurements in order to calculate the signal-to-noise ratio (SNR), absolute contrast, and contrast-to-noise ratio (CNR). Attenuation of the largest stones were also compared. Detectability of urinary stones was assessed by two observers.

RESULTS

Image noise was significantly reduced with DLIR: 7.2 versus 17 and 22 for ASiR-V 70% and FBP, respectively. Similarly, SNR and CNR were also higher compared to the standard reconstructions. When the structures had close attenuation values, contrast was lower with DLIR compared to ASiR-V. Attenuation of stones was also lowered in the DLIR series. Subjective image quality was significantly higher with DLIR. The detectability of all stones and stones >3 mm was excellent with DLIR for the two observers (intraclass correlation [ICC] = 0.93 vs. 0.96 and 0.95 vs. 0.99). For smaller stones (<3 mm), results were different (ICC = 0.77 vs. 0.86).

CONCLUSION

For low-dose abdominopelvic CT, DLIR reconstruction exhibited image quality superior to ASiR-V and FBP as well as an excellent detection of urinary stones.

Influence of Different Arm Positions in the Localizer Radiograph(s) on Patient Dose during Exposure-Controlled CT Examinations of the Neck to Pelvis

Our aim was to examine the impact of different arm positions during imaging of the localizer radiograph(s) on effective dose for exposure-controlled computed tomography (CT) (Siemens/Canon) scans of the neck to pelvis. An anthropomorphic whole-body phantom was scanned from the neck to pelvis with the arms positioned in three different ways during the acquisition of the localizer radiograph: (i) above the head, (ii) alongside the trunk, and (iii) along the trunk with the hands placed on the abdomen. In accordance with clinical routines, the arms were not included in the subsequent helical scans. Effective doses were computed to a standard-sized patient (male/female) using a dedicated system-specific Monte Carlo-based software. Effective doses for the Canon CT scanner for the different alternatives (male/female) were (a) 5.3/6.62 mSv, (b) 5.62/7.15 mSv and (c) 5.92/7.44 mSv. For the Siemens CT scanner, effective doses were (a) 4.47/5.59 mSv, (b) 5.4/6.69 mSv and (c) 5.7/6.99 mSv. Arms placed above the head during localizer radiograph imaging in the current CT procedures substantially reduced the total effective dose to the patient.

An evaluation of DNA double strand break formation and excreted guanine species post whole body PET/CT procedure

Ionizing radiation-induced oxidation and formation of deoxyribonucleic acid (DNA) double strand breaks (DSBs) are considered the exemplar of genetic lesions. Guanine bases are most prone to be oxidized when DNA and Ribonucleic acid (RNA) are damaged. The repair processes that are initiated to correct this damage release multiple oxidized guanine species into the urine. Hence, the excretion of guanine species can be related with the total repair process. Our study quantified the total DSBs formation and the amount of guanine species in urine to understand the DNA break and repair process after whole body (WB) exposure to 18F-FDG positron emission tomography/computed tomography (PET/CT). A total of 37 human participants were included with control and test groups and the average radiation dose was 27.50 ± 2.91 mSv. γ-H2AX foci assay in the collected blood samples was performed to assess the DSBs, and excreted guanine species in urine were analyzed by a competitive ELISA method. We observed a significant increase of DNA damage that correlated well with the increasing dose (p-value 0.009) and body weight (p-value 0.05). In the test group, excreted guanine species in urine sample significantly increased (from 24.29 ± 5.82 to 33.66 ± 7.20 mg/mmol creatinine). A minimum (r2 = 0.0488) correlation was observed between DSBs formation and excreted guanine species. A significant difference of DNA damage and 8-OHdG formation was seen in the test group compared to controls. Larger population studies are needed to confirm these observations, describe the fine-scale timing of changes in the biomarker levels after exposure, and further clarify any potential risks to patients from PET/CT procedures.

An Oropharyngeal Obstructive Lesion in a Neonate

Neonatal HNT in the pharynx is a rare cause of respiratory distress and poor feeding in the newborn, but must be differentiated from teratoma, encephalocele, and nasal glioma. While surgical resection is the preferred treatment modality, we posit there is a role for sclerosis of the glial heterotopic cyst if complete surgical excision is not possible or carries risk of high morbidity. Here, we present a case of a 7-day-old neonate presenting with acute respiratory distress found to have a nasopharyngeal/oropharyngeal mass ultimately treated with sclerotherapy at 9 months of age.

Evaluation der Aufnahmekriterien von Patienten nach Verkehrsunfall in den Schockraum

Hintergrund

Die aktuelle S3-Leitlinie Polytrauma/Schwerverletzten-Behandlung der Deutschen Gesellschaft für Unfallchirurgie (DGU) empfiehlt bei einem Pkw-Unfall mit einer Geschwindigkeitsveränderung von delta >30 km/h die Versorgung in einem Schockraum ohne Berücksichtigung der Verletzungen des Patienten. Ziel dieser Studie war es zu untersuchen, ob Patienten, die ausschließlich aufgrund dieses Kriteriums über einen Schockraum aufgenommen wurden, relevante Verletzungen aufwiesen, die intensivmedizinische Behandlungen oder (Not‑)Operationen benötigten.

Methode

Nach einem Pkw-Unfall wurden Patienten ohne spezifische Verletzung, bei denen ausschließlich eine Geschwindigkeitsveränderung von delta >30 km/h vorlag (Empfehlungsgrad B der S3-Leitlinie), der Studiengruppe, Patienten mit Verletzungen gem. Empfehlungsgrad A der Leitlinie der Vergleichsgruppe zugeordnet. Ein schockraumrelevantes Trauma wurde als Injury Severity Score (ISS) ≥16, operative Versorgung innerhalb 24 h, intensivmedizinische Überwachung >24 h, Versterben während des Krankenhausaufenthalts sowie DGU-Basiskollektiv (MAIS3+ oder MAIS2 mit Intensivverweildauer >24 h bzw. Versterben während des Krankenhausaufenthalts) definiert.

Ergebnisse

Der Vergleich zeigte einen hochsignifikanten Unterschied in Bezug auf den mittleren ISS (p ≤ 0,001), ein schockraumrelevantes Trauma (ISS ≥16; p ≤ 0,001), eine intensivmedizinische Versorgung >24 h (p ≤ 0,001), Operation innerhalb von 24 h nach Krankenhausaufnahme (p ≤ 0,001), Letalität (p ≤ 0,001) sowie DGU-Basiskollektiv (p ≤ 0,001). Anhand dieser Ergebnisse konnte gezeigt werden, dass innerhalb der Studiengruppe (Geschwindigkeitsveränderung von delta >30 km/h; Empfehlungsgrad B der S3-Leitlinie) lediglich ein Patient eine Traumafolge aufwies, die eine intensivmedizinische Behandlung >24 h oder eine Operation nötig machte. Studien- und Vergleichsgruppen waren in Bezug auf das mittlere Alter (p = 1,778), das männliche Geschlecht (p = 0,1728) sowie die durchschnittliche Unfallgeschwindigkeit (p = 0,4606) vergleichbar.

Diskussion

Ein alleiniges Vorliegen eines Pkw-Unfalls mit einer Geschwindigkeitsveränderung von delta >30 km/h kann nicht als adäquater Prädiktor für ein schockraumrelevantes Trauma gesehen werden. Weitere Studien könnten durch eine Leitlinienanpassung eine weiterhin sichere und hochwertige Patientenversorgung bei Reduktion von personellen und finanziellen Belastungen ermöglichen.

Spectral CT in clinical routine imaging of neuroendocrine neoplasms

AIM

To evaluate the potential of new spectral computed tomography (SCT)-based tools in patients with neuroendocrine neoplasms (NEN).

MATERIAL AND METHODS

Eighty-eight consecutive patients with NENs were included prospectively. The patients underwent multiphase CT with spectral and standard mode. The signal-to-noise ratio (SNR)/contrast-to-noise-ratio (CNR)_{tumour-to-liver}, iodine concentrations (ICs, total tumour/hotspot) and attenuation slopes in virtual monochromatic images (VMIs) were used to assess NEN-specific SCT values in primary tumours and metastatic lesions and investigate a possible lesion contrast improvement as well as possible correlations of SCT parameters to primary tumour location and tumour grade. Furthermore, the usability of SCT parameters to differentiate between the primary tumour and metastatic lesions, and to predict tumour response after 6-months follow-up was analyzed. The applied dose of spectral and standard mode was compared intra-individually.

RESULTS

SNR/CNR_{tumour-to-liver} significantly increased in low-energy VMIs. NENs showed significant differences in ICs between primary and metastatic lesions for both absolute and normalised values (p<0.001) regardless of whether the total tumour or the hotspot was measured. There was also a significant difference in the attenuation slope (p<0.001). No significant correlations were found between SCT and tumour grade. A tumour response prediction by SCT parameters was not possible. The applied dose was comparable between the scan modes.

CONCLUSION

SCT was comparable regarding applied dose, improved tumour contrast, and contributed to differentiation between primary NEN and metastasis.

Pulmonary Embolism in Pregnancy

Even though venous thromboembolism is a leading cause of maternal mortality in high-income countries, there are limited high-quality data to assist clinicians with the management of pulmonary embolism in this patient population. Diagnosis, prevention, and treatment of pregnancy-associated pulmonary embolism are complicated by the need to consider fetal, as well as maternal, well-being. Recent studies suggest that clinical prediction rules and D-dimer testing can reduce the need for diagnostic imaging in a subset of patients. Low-molecular-weight heparin is the preferred anticoagulant for both prophylaxis and treatment in this setting. Direct oral anticoagulants are contraindicated during pregnancy and in breastfeeding women. Thrombolysis or embolectomy should be considered for pregnant women with pulmonary embolism complicated by hemodynamic instability. Treatment of pregnancy-associated pulmonary embolism should be continued for at least 3 months, including 6 weeks postpartum. Management of anticoagulants at the time of delivery should involve a multidisciplinary individualized approach that uses shared decision making to take patient and caregiver values and preferences into account.

Whole-body computed tomography is safe, effective and efficient in the severely injured hemodynamically unstable trauma patient

Trauma is a complex pathology that requires an experienced multidisciplinary team with an inherent quick decision-making capacity, given that a few minutes could represent a matter of life or death. These management decisions not only need to be quick but also accurate to be able to prioritize and to efficiently control the injuries that may be causing impending hemodynamic collapse. In essence, this is the cornerstone of the concept of damage control trauma care. With current technological advances, physicians have at their disposition multiple diagnostic imaging tools that can aid in this prompt decision-making algorithm. This manuscript aims to perform a literature review on this subject and to share the experience on the use of whole body computed tomography as a potentially safe, effective and efficient diagnostic tool in cases of severely injured trauma patients regardless of their hemodynamic status. Our general recommendation is that, when feasible, perform a whole body computed tomography without interrupting ongoing hemostatic resuscitation in cases of severely injured trauma patients with or without signs of hemodynamic instability. The use of this technology will aid in the decision-making of the best surgical approach for these patients without incurring any delay in definitive management and/or increasing significantly their radiation exposure.

Correlation Between Traumatic Skin and Subcutaneous Injuries and the Severity of Polytrauma Injury

PURPOSE

 To examine the relationship between superficial lesions (such as bruises, hematomas, deep abrasions, and soft tissue emphysema) and internal post-traumatic injuries, assessed using whole-body computed tomography (WBCT), and to determine if these are valid markers for internal injuries.

METHODS AND MATERIALS

 250 patients who underwent WBCT emergency scans for suspected polytrauma were retrospectively analyzed after institutional review board approval of the study. The scans were carried out on patients who met the criteria for standard operating procedures for WBCT emergency scans. WBCT covering the entire head, neck, chest, and abdomen (including pelvis and proximal lower extremities) and at least one phase with intravenous contrast agent were included in the study. Initial analyses of immediate WBCT scans was carried out by a consultant radiologist and a radiological resident. The first reading focused on internal damage that needed immediate therapy. The second reading focused on a detailed analysis of the skin and subcutaneous tissue and their relation to internal injuries without the time pressure of an emergency setting, carried out by another experienced radiologist. All skin lesions and the degree of penetration and a comparison between the two readings were reported in tables.

RESULTS

 Superficial lesion of the chest was detected in 19 patients, 17 of them had an internal injury of the thorax while only two patients, with hematoma of the chest wall, had no internal injuries. Skin and subcutaneous lesions of the chest had the strongest association with an internal injury. Skin lesions of the abdominal wall were observed in 30 patients. In only 11 cases, these lesions were correlated with internal injuries, such as fractures or active bleeding. 52 skin and subgaleal lesions of the scalp were observed. In 20 of these patients, an intracranial or internal injury was detected. In 3 patients, skin abrasions of the neck were present and in only one of them, this finding was associated with an internal injury.

CONCLUSION

 Trauma patients whose history and clinical presentation meet the standard operating procedures for WBCT emergency scans and who present with a cutaneous lesion, especially at the neurocranium or chest wall, should be observed for internal injuries by WBCT.

KEY POINTS

  · Presence or lack of a superficial injury of the abdominal wall is not a reliable predictive indication of any internal abdominal injury.. · Superficial lesions of the chest and the neurocranium require a CT scan.. · Superficial injuries of the chest wall had the strongest association with internal injuries..

CITATION FORMAT

· Klempka A, Fischer C, Kauczor H et al. Correlation Between Traumatic Skin and Subcutaneous Injuries and the Severity of Trauma. Fortschr Röntgenstr 2021; 193: 177 - 185.

Patients' and Physicians' Knowledge of Radiation Exposure Related to Spine Surgery

STUDY DESIGN

Cross-sectional survey.

OBJECTIVE

Examine patients' and physicians' estimates of radiation exposure related to spine surgery.

SUMMARY OF BACKGROUND DATA

Patients are commonly exposed to radiation when undergoing spine surgery. Previous studies suggest that patients and physicians have limited knowledge about radiation exposure in the outpatient setting. This has not been assessed for intraoperative imaging.

METHODS

A questionnaire was developed to assess awareness/knowledge of radiation exposure in outpatient and intraoperative spine care settings. Patients and surgeons estimated chest radiograph (CXR) equivalent radiation from: cervical and lumbar radiographs (anterior-posterior [AP] and lateral), computed tomography (CT), magnetic resonance imaging (MRI), intraoperative fluoroscopy, and intraoperative CT (O-arm). Results were compared to literature-reported radiation doses.

RESULTS

Overall, 100 patients and 26 providers completed the survey. Only 31% of patients were informed about outpatient radiation exposure, and only 23% of those who had undergone spine surgery had been informed about intraoperative radiation exposure. For lumbar radiographs, patients and surgeons underestimated CXR-equivalent radiation exposures: AP by five-fold (P < 0.0001) and seven-fold (P < 0.0001), respectively, and lateral by three-fold (P < 0.0001) and four-fold (P = 0.0002), respectively. For cervical CT imaging, patients and surgeons underestimated radiation exposure by 18-fold (P < 0.0001) and two-fold (P = 0.0339), respectively. For lumbar CT imaging, patients and surgeons underestimated radiation exposure by 31-fold (P < 0.0001) and three-fold (P = 0.0001), respectively. For intraoperative specific cervical and lumbar imaging, patients underestimated radiation exposure for O-arm by 11-fold (P < 0.0001) and 22-fold (P = 0.0002), respectively. Surgeons underestimated radiation exposure of lumbar O-arm by three-fold (P = 0.0227).

CONCLUSION

This study evaluated patient and physician knowledge of radiation exposure related to spine procedures. Underestimation of radiation exposure in the outpatient setting was consistent with prior study findings. The significant underestimation of intraoperative cross-sectional imaging (O-arm) is notable and needs attention in the era of increased use of such technology for imaging, navigation, and robotic spine surgery.

LEVEL OF EVIDENCE

4.

Detailed information gain and therapeutic impact of whole body computed tomography supplementary to conventional radiological diagnostics in blunt trauma emergency treatment: a consecutive trauma centre evaluation

Purpose

The indication of whole body computed tomography (WBCT) in the emergency treatment of trauma is still under debate. We were interested in the detailed information gain obtained from WBCT following standardized conventional imaging (CI).

Methods

Prospective study including all emergency trauma centre patients examined by CI (focused assessment of sonography in trauma, chest and pelvic X-ray) followed by WBCT from 2011 to 2017. Radiology reports were compared per patient for defined body regions for number and severity of injuries (Abbreviated Injury Scale, AIS; Injury Severity Score, ISS), incidental findings and treatment consequences (Wilcoxon signed rank test, Spearman rho, Chi-square).

Results

1271 trauma patients (ISS 11.3) were included in this study. WBCT detected more injury findings than CI in the equivalent body regions (1.8 vs. 0.6; p < 0.001). In 44.4% of cases at least one finding was missed by CI alone. Compared to WBCT, injury severity of specified body regions was underestimated by CI on average by an AIS of 1.9 (p < 0.001). In 22.0% of cases injury severity increased by an AIS ≥ 2 following WBCT. In 16.8% of patients additional injury findings resulted in a change of treatment (number needed to profit, NNP = 6 patients): NNP decreased from 25 for patients with an ISS < 7 up to nearly 2 for patients with an ISS > 25 at final evaluation, thereby demonstrating a significant improvement in the NNP with increasing ISS (rho = 0.33, p < 0.001). Moreover, WBCT in 88.4% of patients identified ≥ 1 incidental finding (mean 3.4) vs. 28.9% by CI only (p < 0.001). Overall, WBCT had treatment consequences in 31.9% of cases (NNP = 3.1).

Conclusions

The application of WBCT in addition to CI in the emergency treatment of trauma had therapy consequences for almost every third patient. On the other hand, WBCT appeared not to be indicated (ISS < 8) in at least 2/5 of patients.

Electronic supplementary material

The online version of this article (10.1007/s00068-020-01502-1) contains supplementary material, which is available to authorized users.

Replacing true unenhanced imaging in renal carcinoma with virtual unenhanced images in dual-energy spectral CT: a feasibility study

AIM

To investigate the clinical value of virtual unenhanced (VNC) spectral computed tomography (CT) images to replace the conventional true unenhanced spectral CT images (TNC) in diagnosing renal carcinoma.

MATERIALS AND METHODS

Fifty-six cases of renal carcinoma confirmed by histopathology underwent conventional plain CT and contrast-enhanced spectral CT at arterial phase (AP) and venous phase (VP). VNC images were generated on an AW4.6 workstation. The CT attenuation, image noise, contrast-to-noise ratio (CNR), and signal-noise-ratio (SNR) of the renal lesions and normal kidneys, long and short axis diameters of the lesion were measured from the three image sets and analysed using one-way analysis of variance (ANOVA). Two radiologists evaluated image quality subjectively using a five-point score, and lesion signature using a three-point score. Image quality scores were compared statistically and tested for consistency.

RESULTS

The two reviewers had good agreement for subjective evaluation (Kappa>0.70) and there was no difference in the quality of the scores among the three image groups. The lesion signature scores were all above the acceptable level. The CNR and SNR values in VNC were significantly higher than in TNC (p<0.05). VNC images had lower renal noise than in TNC (p<0.05). There was no difference in the long and short axis diameters of the lesion among the three image groups. VNC had higher CT attenuation values for the lesion and kidney than TNC (p<0.05), but the differences were <5 HU.

CONCLUSION

VNC images in spectral CT may be used to replace the conventional plain CT to reduce imaging duration and radiation dose in diagnosing renal carcinoma.

Impact of 80 kVp with iterative reconstruction algorithm and low-dose contrast medium on the image quality of craniocervical CT angiography

PURPOSE

To assess the image quality of 80-kVp craniocervical CT angiography (CCCTA) protocol combined with adaptive statistical iterative reconstruction-V (ASIR-V) and low-dose contrast medium (CM).

METHODS

A total of 119 patients were randomly divided into three groups. For group A, 120-kVp protocol was followed with 60 ml CM and filtered back projection; for group B, 80-kVp protocol with 60 ml CM and ASIR-V; and for group C, 80-kVp protocol with 45 ml CM and ASIR-V. Both subjective and objective image quality and radiation doses were evaluated.

RESULTS

Arterial attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the head, neck, and shoulder regions were significantly higher in groups B and C compared with group A. Group C yielded significantly better subjective image quality than that observed in groups A and B (both p < .05). As compared with group A, effective radiation dose and the iodine load of group C were reduced by 51.4% and 25%, respectively.

CONCLUSIONS

The CCCTA protocol with 80 kVp, ASIR-V, and 45 ml of CM injected at 3 ml/s significantly reduced the radiation dose, iodine load, and iodine delivery rate while providing better subjective and objective image quality, including higher arterial enhancement and a higher SNR and CNR compared with the 120-kVp protocol.

DNA double-strand breaks of human peripheral blood lymphocyte induced by CT examination of oral and maxillofacial region

OBJECTIVES

To explore whether a computed tomography (CT) examination of the head and neck region induces biological damage and whether the damage was correlated with the radiation dose.

MATERIALS AND METHODS

Peripheral blood was taken from 33 individuals who received head and neck CT examinations. Blood samples were divided into three groups: the control group and the in vivo and in vitro irradiation groups. The number of DNA double-strand breaks was estimated by comparing the changes in the rates of γ-H2AX foci formation in the peripheral blood before and after CT examination. The absorbed dose and effective dose were calculated with the software VirtualDose based on the Monte Carlo method, and the absorbed doses in blood were estimated accordingly.

RESULTS

The γ-H2AX foci rates were increased in the in vivo (p < 0.001) and in vitro irradiation groups (p < 0.001) after CT examination when compared with those in the control group. The rate of γ-H2AX foci formation showed linear dose-responses for the CT dose index volume (CTDI_vol), dose-length product (DLP), and blood dose after CT examination.

CONCLUSIONS

A CT examination of the head and neck region provides a high enough radiation dose to induce DNA double-strand breaks in cells in the peripheral blood. There was a linear correlation between the formation of DNA double-strand breaks and radiation doses after CT examination.

CLINICAL RELEVANCE

In addition to ensuring image quality, in a real clinical situation, the scanning area should be strictly administered, and repeated operations should be avoided to minimise the patient's radiation dose.

The Value of Low-dose Prospective Dual-energy Computed Tomography with Iodine Mapping in the Diagnosis of Gastric Cancer

OBJECTIVES

This study investigated the radiation dose and value of prospective dualenergy computed tomography (DECT) in the diagnosis of gastric cancer.

METHODS

Sixty patients scheduled for computed tomography (CT) for preoperative staging were divided into two groups. Thirty patients (Group A) underwent a single contrast-enhanced abdominal CT acquisition using a dual-source mode (100 kV/140 kV). Weighted average images of the two-kilovolt acquisitions and iodine maps were created. The remaining 30 patients underwent a standard CT scan (Group B). Two observers performed a blinded read of the images for gastric lesions, evaluating the image quality and recording effective dose.

RESULTS

During the blinded read, observers found 90% (27/30) of the cancers in both groups. The mean imaging quality scores were 2.1±0.9 for Group A, and 2.3±1.1 for Group B. The effective mean doses were 6.59±0.59 mSv and 25.86±0.44 mSv for Groups A and B, respectively. Compared with the control group (B), the imaging quality in the low-dose group decreased a little, but the radiation dose substantially decreased by 74.6%.

CONCLUSION

The new DECT technique is valuable for examining gastric cancer patients. The dualkV scan mode can substantially reduce radiation dose while preserving good diagnostic image quality.

Paediatric computed tomography and subsequent risk of leukaemia, intracranial malignancy and lymphoma: a nationwide population-based cohort study

Red bone marrow and brain tissue are highly radiosensitive in children. We investigate the relationship between childhood computed tomography (CT) exposure and leukaemia, intracranial malignancy and lymphoma. All participants in the study were aged less than 16 years. A total of 1,479 patients in the leukaemia group, 976 patients in the intracranial malignancy group and 301 patients in the lymphoma group were extracted from the Catastrophic Illness Certificate Database in Taiwan as the disease group. In total, 126,677 subjects were extracted from the Longitudinal Health Insurance Database 2010 of the Taiwan National Health Insurance Research Database as the non-disease group. The odds ratios (ORs) and 95% confidence intervals (CIs) for childhood CT exposure and times of childhood CT were estimated. Childhood CT exposure was correlated to the intracranial malignancy group in both one-year (OR = 1.95, 95% CI 1.40-2.71, p < 0.001) and two-year (OR = 1.56, 95% CI 1.04-2.33, p = 0.031) exclusion periods. The time of childhood CT was also correlated to intracranial malignancy in both one-year (OR = 1.69, 95% CI 1.34-2.13, p < 0.001) and two-year (OR = 1.55, 95% CI 1.17-2.04, p = 0.002) exclusion periods. The results indicated that childhood CT exposure was correlated with an increased risk of future intracranial malignancy.

Radiation dose from computed tomography in patients with acute pancreatitis: an audit from a tertiary care referral hospital

BACKGROUND

There is a limited data on the radiation dose from computed tomography (CT) in patients with acute pancreatitis (AP). The present study evaluated the radiation dose from CT scans in patients with AP.

MATERIAL

A retrospective review of CT reports of patients with AP was conducted. The type of CT scan (non-contrast vs. single-phase vs. biphasic CT) was recorded. The mean number of CT scans and cumulative radiation dose was calculated. The indications and abnormalities on biphasic CT scans were recorded. The radiation doses between different types of the scan were compared.

RESULTS

495 CT studies in 351 patients were evaluated. In patients (n = 78, 22.2%) undergoing multiple CT scans, mean number of CT scans per patient and mean radiation dose were 2.64 ± 1.18 (range 2-9) and 24 ± 15 mSv (range 8.3-79.8 mSv), respectively. The mean radiation dose was significantly greater in patients with modified CT severity index ≥ 8 (n = 63) [25.08 mSv vs. 18.96 mSv, (P = 0.048)]. 61 (12.32%) biphasic scans were performed. A definite indication for a biphasic CT scan was identified in 20 (32.7%) patients. Arterial abnormalities were detected in 6 (9.8%) patients undergoing CT for defined indication. Mean radiation dose in this group was 13.26 ± 7.64 mSv (range 3.42-38.27 mSv) which was significantly greater than the single venous phase scan (7.96 ± 3.48 mSv, P < 0.001).

CONCLUSION

There is a potential for substantial radiation exposure from CT scans to patients with AP. Patients with severe AP and those undergoing biphasic scans have significantly higher radiation exposure. Hence, routine arterial phase acquisition should be avoided.

Implementation of a new Single-Pass Whole-Body Computed Tomography Protocol: Is it safe, effective and efficient in patients with severe trauma?

Purpose:

The objective of this study was to evaluate the implementation of a new single-pass whole-body computed tomography Protocol in the management of patients with severe trauma.

Methods:

This was a descriptive evaluation of polytrauma patients who underwent whole-body computed tomography. Patients were divided into three groups: 1. Blunt trauma hemodynamically stable 2. Blunt trauma hemodynamically unstable and 3. Penetrating trauma. Demographics, whole-body computed tomography parameters and outcome variables were evaluated.

Results:

Were included 263 patients. Median injury severity score was 22 (IQR: 16-22). Time between arrival to the emergency department and completing the whole-body computed tomography was under 30 minutes in most patients [Group 1: 28 minutes (IQR: 14-55), Group 2: 29 minutes (IQR: 16-57), and Group 3: 31 minutes (IQR: 13-50; p= 0.96)]. 172 patients (65.4%) underwent non-operative management. The calculated and the real survival rates did not vary among the groups either [Group 1: TRISS 86.4% vs. real survival rate 85% (p= 0.69); Group 2: TRISS 69% vs. real survival rate 74% (p= 0.25); Group 3: TRISS 93% vs. real survival rate 87% (p= 0.07)].

Conclusion:

This new single-pass whole-body computed tomography protocol was safe, effective and efficient to decide whether the patient with severe trauma requires a surgical intervention independently of the mechanism of injury or the hemodynamic stability of the patient. Its use could also potentially reduce the rate of unnecessary surgical interventions of patients with severe trauma including those with penetrating trauma.

Uso de la tomografía corporal total en pacientes con trauma grave

Introducción. La tomografía corporal (TC) total en la evaluación de pacientes con trauma grave, puede ser una herramienta eficaz y segura para decidir entre un tratamiento quirúrgico y uno no quirúrgico, pero aún no son claras las implicaciones diagnósticas y los riesgos asociados con esta técnica. Métodos. Se incluyeron pacientes mayores de 15 años con trauma grave que fueron sometidos a TC total. Se evaluaron la seguridad, la efectividad y la eficiencia por medio de los parámetros de incidencia de nefropatía inducida por los medios de contraste, dosis total de radiación por paciente, proporción de casos en los que la TC total cambió el manejo, y el retraso en el diagnóstico. Resultados. Se incluyeron 263 pacientes, 83 % sufrieron trauma cerrado y 17 % sufrieron trauma penetrante. La gravedad de la lesión fue mayor en estos últimos y, sin embargo, el trauma cerrado con inestabilidad hemodinámica se presentó con mayores grados de choque. El 65 % de los pacientes recibió tratamiento selectivo no operatorio. Entre los subgrupos, no hubo diferencias significativas en el tiempo entre el ingreso a la sala de urgencias y la toma de la TC total (p=0,96) y, en la mayoría de los casos, el tiempo entre la práctica de la TC total y el diagnóstico de presencia o ausencia de heridas fue menor de 25 minutos. La mediana de radiación total estuvo por debajo de 20 mSv en todos los grupos. No hubo diferencias significativas en la mortalidad (p=0,17). Conclusión. La TC total es una herramienta segura y eficiente para decidir entre un tratamiento quirúrgico y uno no quirúrgico en los casos de trauma grave, independientemente del mecanismo de la lesión o la estabilidad hemodinámica al ingreso.

Balancing act between quantitative and qualitative image quality between nonionic iodinated dimer and monomer at various vessel sizes during computed tomography: a phantom study

PURPOSE

Investigate the impact of nonionic dimer and monomer on iodine quantification in different vessel sizes when employing a vascular specific phantom and varying iodinated contrast media (ICM) concentrations during computed tomography (CT).

MATERIALS AND METHODS

We created a vascular specific phantom (30 cm) to simulate human blood vessel diameters (25 cylinders of different diameters: 10 × 9mm, 10 × 12mm and 5 × 21mm). The phantom was filled with two ICM separately: Group: Iohexol(monomer)350 mg ml^-1 and B: Iodixanol(Dimer)320 mg ml^-1. Cylinders of same size were filled with increasing ICM concentration(10%-100%) while large cylinders were filled in quartiles(25%-100%). Phantom was scanned with different tube potential (80-140kVp), current (50-400mAs), reconstruction method [filtered back projection (FBP), hybrid-based iterative reconstruction (HBIR) and model-based iterative reconstruction (MBIR)] for each ICM. Chi-square was employed to compare mean opacification, contrast/noise ratio (CNR) and noise. Qualitative analysis was assessed by Visual grading characteristic (VGC) and Cohens-kappa analyses.

RESULTS

At 80 and140kVp significant difference in opacification between Group A (2054 ± 1040HU and 1696 ± 1027HU) and B (2169 ± 1105HU and 1568 ± 1034HU) was demonstrated (p < 0.001). However, at 100 and 120kVp no difference was noted (p > 0.05). When comparing image noise, it was higher in Group A compared to B (p < 0.05). CNR was higher in Group B (119.99 ± 126.10HU) than A (107.09 ± 102.56HU) (p < 0.0001). VGC: Group A outperformed B in image opacification in all vessel sizes and ICM concentrations except at medium vessels with concentration group 2(0.4-0.6 mg ml^-1). Cohens'-kappa: agreement in opacification between each ICM group and iodine concentration 1(0-0.3 mg ml^-1): κ = 0.253 and 0.014 respectively, concentration 2(0.4-0.6 mg ml^-1):κ = -0.017 and -0.005 respectively and concentration 3(0.7-1 mg ml^-1):κ = 0.031 and 0.115 respectively.

CONCLUSION

Nonionic dimer (Iodixanol) surpasses monomer (Iohexol) in quantitative image quality assessment by having lower image noise and higher CNR during CT.

APPLICATION OF TIME-AVERAGED AND INTEGRAL-BASED MEASURE FOR MEASUREMENT RESULTS VARIABILITY REDUCTION IN GSM/DCS/UMTS SYSTEMS

Since EMF levels from wireless telecommunication networks are non-stationary and exhibit large temporal variations, the use of continuous measurements during extended periods (preferably 24 h or longer) with a data-logging system is required. Because of the short-term variations of E field, the 6-min measurements and 6-min averaged results to obtain the mean level strength at a given place appear to be dependent on the time of measurements during the day. This paper presents a new (integral-based) measure to evaluate electromagnetic exposure. The new measure is a pure physical descriptor of the amount of exposed energy density (a parameter accumulated from instantaneous power density values in time). To confirm previous observations, continuous measurements with personal exposure metre were recorded 24 h a day for two weeks at every location in urban area, 14 different locations in total. Additionally, to check temporal variations and repeatability of exposure assessment, a week of prolonged measurements was taken 6 months later, making in total three weeks of measurements at 2 locations. Day-to-day repeatability of RF-EMF exposure was analysed through the time-averaged and integral-based measure. The analysis is based on approximately 5.1 million data samples (1.7 million for each band). The ratio between the maximum and minimum instantaneous (maximum and minimum 6-min averaged) E field values during the day could reach up to 25 dB (20 dB). Therefore, great variability in the results may occur. By applying the 24 h time-averaged and integral-based measure on a 24 h data set of measurements, the variability of daily exposure could stay within ±20% of the week mean level obtained either with the time-averaged or integral-based measure. Both, the time-averaged E field and integral-based power density exposures of the general public in all locations were found to be well below the general public exposure limits of the ICNIRP guidelines.