Brain Computed Tomography Examinations Research Articles

Investigation of lifetime attributable risk associated with brain CT scans: A retrospective study in North Jordan

ObjectivesThis study aimed to investigate the lifetime attributable risk (LAR) associated with brain Computed Tomography (CT) scans, focusing on diverse dimensions, including radiation doses and technical factors. MethodsA retrospective study was conducted spanning from May 2021 to June 2022 across multiple hospitals in North Jordan. Data from 1505 adult patients undergoing brain CT scans were analyzed. The effective dose (E), calculated based on the dose length product (DLP) and tissue weighting factors, provided a comprehensive assessment of radiation exposure. Statistical analysis was employed to assess gender differences in mean effective doses across different age groups. LAR estimates were calculated for male and female patients. ResultsThe mean effective doses showed no significant gender differences, except in the 60–70 age group. However, LAR estimates revealed potential increased cancer risk, with values of 0.00029 for males and 0.000232 for females. These findings underscore the importance of scrutinizing radiation doses and technical parameters in brain CT examinations to mitigate potential risks. ConclusionThis study contributes valuable insights into the refinement of CT practices, emphasizing the necessity of optimizing radiation doses for patient safety in brain CT examinations. Addressing these factors is crucial to minimize the lifetime attributable risk associated with this imaging modality, ultimately enhancing patient care and outcomes.

Thyroid Absorbed Dose from Brain CT Examinations in Different Age Groups of Pediatric Based on Monte Carlo Simulation

Background: This study was designed to assess the thyroid absorbed dose from brain computed tomography (CT) scans across various pediatric age groups, utilizing Monte-Carlo simulation and thermoluminescent dosimeters (TLDs). Methods: We used the Monte Carlo N-particle (MCNP) transport code to model the spiral CT scan of the brain and calculated the average thyroid dose for each pediatric age group. Techniques for variance reduction, such as Time cutoff, Energy cutoff, and Russian roulette, were implemented. Additionally, a cross-sectional study measured the average thyroid absorbed dose in 45 patients under 20 years using TLD dosimetry. The data were analyzed with SPSS software at a 95% confidence interval (CI). Results: The absorbed thyroid dose for an irradiation time of 1 second and 120 mA across the age groups 0 - 5, 6 - 10, 11 - 15, and 16 - 20 years for boys was 4.165 ± 0.028, 3.802 ± 0.036, 3.861 ± 0.031, and 3.021 ± 0.029 mGy, respectively, and for girls, it was 4.185 ± 0.024, 3.852 ± 0.044, 4.052 ± 0.028, and 4.072 ± 0.047 mGy, respectively. For a dose of 110 mAs, the results for boys were 3.711 ± 0.037, 3.660 ± 0.026, 3.251 ± 0.019, and 3.204 ± 0.031 mGy, respectively, and for girls were 3.882 ± 0.040, 3.842 ± 0.032, 3.412 ± 0.026, and 3.619 ± 0.029 mGy, respectively (P < 0.001). Conclusions: Comparing these results with experimental studies indicates the feasibility of using less computationally intensive methods. The thyroid dose received by girls was higher than that for boys, aligning with findings from experimental studies and other research.

Reporting Diagnostic Reference Levels for Paediatric Patients Undergoing Brain Computed Tomography.

Brain computed tomography (CT) is a diagnostic imaging tool routinely used to assess all paediatric neurologic disorders and other head injuries. Despite the continuous development of paediatric CT imaging, radiation exposure remains a concern. Using diagnostic reference levels (DRLs) helps to manage the radiation dose delivered to patients, allowing one to identify an unusually high dose. In this paper, we propose DRLs for paediatric brain CT examinations in Saudi clinical practices and compare the findings with those of other reported DRL studies. Data including patient and scanning protocols were collected retrospectively from three medical cities for a total of 225 paediatric patients. DRLs were derived for four different age groupings. The resulting DRL values for the dose-length product (DLP) for the age groups of newborns (0-1 year), 1-y-old (1-5 years), 5-y-old (5-10 years) and 10-y-old (10-15 years) were 404 mGy cm, 560 mGy cm, 548 mGy cm, and 742 mGy cm, respectively. The DRLs for paediatric brain CT imaging are comparable to or slightly lower than other DRLs due to the current use of dose optimisation strategies. This study emphasises the need for an international standardisation for the use of weight group categories in DRL establishment for paediatric care in order to provide a more comparable measurement of dose quantities across different hospitals globally.

Evaluation of image quality, organ doses, effective dose, and cancer risk from pediatric brain CT scans

purposeThe present study was conducted to assess organ doses, effective dose, and image quality, and to estimate the risk of exposure-induced cancer death (REID) in pediatric brain computed tomography examinations. MethodsThis investigation was performed on 179 pediatric patients (99 men and 80 women) under 12 years old who underwent non-contrast brain CT scans. Patients were classified into four age groups of ≤ 1, 2–5, 6–9, and 10–12 years old. Organ doses and effective doses were calculated using the ImpactDose program. Cancer risk models presented in the BEIR VII report were used to estimate REID values. Image quality assessment in this study was performed by measuring image quality parameters such as noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). ResultsThe highest organ dose in all age groups belonged to the brain. The mean REID values were 12.34 per 100,000 males and 16.77 per 100,000 females. REID values decreased with the increasing age of patients in both genders and were higher for female children than male children. The mean SNR of gray matter, SNR of white matter, and CNR were 11.04, 10.5, and 2.31, respectively. ConclusionsAccording to the results of this study, brain CT scans in children are associated with an increased potential risk of cancer. Therefore, minimizing unnecessary radiation exposure in pediatric patients and using alternative imaging modalities are of particular importance. Moreover, optimizing the radiation parameters while maintaining the diagnostic image quality in children should be considered.

Sample Size and Estimation of Standard Radiation Doses for Pediatric Brain CT.

Estimation of the standard radiation dose at each imaging facility is required for radiation dose management, including establishment and utilization of the diagnostic reference levels. We investigated methods to estimate the standard dose for pediatric brain computed tomography (CT) using a small number of data. From 980 pediatric brain CT examinations, 25, 50, and 100 examinations were randomly extracted to create small, medium, and large datasets, respectively. The standard dose was estimated by applying grouping and curve-fitting methods for 20 datasets of each sample size. For the grouping method, data were divided into groups according to age or body weight, and the standard dose was defined as a median value in each group. For the curve-fitting methods, logarithmic, power, and bilinear functions were fitted to plots of radiation dose against age or weight, and the standard dose was calculated at the designated age or weight using the derived equation. When the sample size was smaller, the random variations of the estimated standard dose were larger. Better estimation of the standard dose was achieved with the curve-fitting methods than with the grouping method. Power fitting appeared to be more effective than logarithmic and bilinear fittings for suppressing random variation. Determination of the standard dose for pediatric brain CT by the curve-fitting method is recommended to improve radiation dose optimization at facilities performing the imaging procedure infrequently.

Radiation Dose Management in Pediatric Brain CT According to Age and Weight as Continuous Variables.

The diagnostic reference levels (DRLs) for pediatric brain computed tomography (CT) are provided for groups divided according to age. We investigated the relationships of radiation dose indices (volume CT dose index and dose length product) with age and weight, as continuous variables, in pediatric brain CT. In a retrospective analysis, 980 pediatric brain CT examinations were analyzed. Curve fitting was performed for plots of the CT dose indices versus age and weight, and equations to estimate age- and weight-dependent standard dose indices were derived. Standard dose indices were estimated using the equations, and the errors were calculated. The results showed a biphasic increase in dose indices with increasing age and weight, characterized by a rapid initial and subsequent slow increase. Logarithmic, power, and bilinear functions were well fitted to the plots, allowing estimation of standard dose indices at an arbitrary age or weight. Error analysis suggested that weight was mildly better than age and that the best results were obtained with the bilinear function. Curve fitting of the relationship between CT dose indices and age or weight facilitates the determination of standard dose indices in pediatric brain CT at each facility and is expected to aid the establishment and application of the DRLs.

Risk Estimation of Thyroid Cancer for Children Undergoing Brain CT Examinations

Background: Despite significant diagnosis benefits, the usage of ionizing radiation is not risk-free. The aim of this study was to determine the risk of thyroid cancer for children who exposed from brain computed tomography (CT) scan. Method: In this a cross-sectional study, 90 patients under 20 years of age who underwent brain CT-scan were selected. Parameters such as age, sex, imaging technique, imaging characteristics, and thyroid absorbed dose were considered. We used SPSS software, version 21, at 95% confidence interval to analyze the absorbed dose and risk for each individual. Results: The mean and standard deviation of absorbed the dose for girls and boys for the spiral technique were 3.954±0.393 and 4.72±0.000 mGy and in sequential technique, they were 2.282±0.461 and 1.985±0.431 mGy, respectively. The mean and standard deviation of the absorbed dose in <5 years age group was 5.65±2.00, 3.03±1.34 in 6 to 10 years, 2.63±0.98 in11 to 15 years, and in 16 to 20 years was 2.57±1.04 mGy (P<0.001). There was a significant negative correlation between the absorbed dose and field dimensions (r = -0.604, P<0.001) and slice thickness (r = -0.777, P<0.001). The mean and standard deviation of Lifetime risk for thyroid cancer induction (×105) in <5 years age group in spiral technique was 158.79±322.50 for female subjects and 16.5±42.90 for male patients, which was significantly more than those of other groups and techniques (P<0.001). Conclusion: The rate of thyroid absorbed dose during brain CT-scan was found to be noticeable, especially in spiral CT imaging, for female patients < 5 years. Based on our results, it was associated with an increased risk of thyroid cancer in this age group.

Comparison of the efficiency of the paediatric brain CTs with trauma and non-trauma related indications in the paediatric emergency department

BACKGROUND: This study aimed to determine the appropriateness of the examinations by evaluating the pre-diagnosis of the patients who underwent brain Computed Tomography (CT) in the paediatric emergency departments and the existing pathologies in the brain CTs. In addition, a comparison of the efficiency of the brain CT examinations performed for trauma and non-traumatic reasons was made. MATERIAL AND METHODS: CT’s were examined by dividing into 2 groups according to the indications as trauma (group 1) and non-trauma related (group 2). The 2 groups were compared statistically according to the number of pathologies, distribution of pathologies by gender and age. RESULTS: Pathologies were detected in 9.3% (n = 30) of the patients in the first group and 21.2% (n = 14) of the patients in the second group. A statistically significant difference was found between the groups in terms of whether pathology was detected (p = 0.023). The rate of pathology detection in the group that underwent CT for non-traumatic reasons was statistically significantly higher than the other group. CONCLUSION: Precautions should be taken especially with trauma patients to prevent unnecessary CT scans in the paediatric emergency department. In addition, if a CT scan is planned in the paediatric emergency department with the approval of the paediatrician and radiologist, the CT examinations can be made with more accurate indications.

Computed tomography for patients with drug- or substance-induced seizures: a retrospective analysis

Introduction: Seizure is a common poisoning-related neurological presentation in the emergency department (ED). Although brain computed tomography (CT) is recommended in patients presenting with first seizures, its role in patients with a suspected drug/substance-induced seizure (DSS) remains inconclusive. This study evaluated whether brain CT examination changes the management and outcome of DSS patients. Methods: We retrospectively reviewed adult patients presenting to the ED with a DSS in Linkou and Taipei Chang Gung Memorial Hospital, Taiwan, from January 2008 to December 2015. We also analyzed whether the brain CT examinations found meaningful acute abnormalities and their impact on subsequent management. We compared the differences between DSS patients undergoing CT scans or not to identify factors that affect the decision to arrange brain CT. Results: The study enrolled 97 patients (69 males). The most common cause of DSS was alcohol withdrawal (58.76%), followed by carbon monoxide (12.37%) and stimulants (8.25%). Eight (8.25%) patients developed status epilepticus, 15 (15.46%) were intubated, and 37 (37.76%) were admitted, including 12 (12.26%) to the intensive care unit. Brain CT was performed in 64 (66.0%) patients and four had abnormal reports that led to further imaging studies. The abnormal findings ultimately had no significant clinical impact. Patients who underwent CT scans had a worse Glasgow Coma Scale score (p = 0.024) and higher rate of status epilepticus (p = 0.031). Conclusion: Brain CT does not provide substantial information for the care of DSS patients. Multi-center prospective studies are needed to obtain stronger evidence.

Hydrocephalus: Ventricular Volume Quantification Using Three-Dimensional Brain CT Data and Semiautomatic Three-Dimensional Threshold-Based Segmentation Approach.

ObjectiveTo evaluate the usefulness of the ventricular volume percentage quantified using three-dimensional (3D) brain computed tomography (CT) data for interpreting serial changes in hydrocephalus.Materials and MethodsIntracranial and ventricular volumes were quantified using the semiautomatic 3D threshold-based segmentation approach for 113 brain CT examinations (age at brain CT examination ≤ 18 years) in 38 patients with hydrocephalus. Changes in ventricular volume percentage were calculated using 75 serial brain CT pairs (time interval 173.6 ± 234.9 days) and compared with the conventional assessment of changes in hydrocephalus (increased, unchanged, or decreased). A cut-off value for the diagnosis of no change in hydrocephalus was calculated using receiver operating characteristic curve analysis. The reproducibility of the volumetric measurements was assessed using the intraclass correlation coefficient on a subset of 20 brain CT examinations.ResultsMean intracranial volume, ventricular volume, and ventricular volume percentage were 1284.6 ± 297.1 cm3, 249.0 ± 150.8 cm3, and 19.9 ± 12.8%, respectively. The volumetric measurements were highly reproducible (intraclass correlation coefficient = 1.0). Serial changes (0.8 ± 0.6%) in ventricular volume percentage in the unchanged group (n = 28) were significantly smaller than those in the increased and decreased groups (6.8 ± 4.3% and 5.6 ± 4.2%, respectively; p = 0.001 and p < 0.001, respectively; n = 11 and n = 36, respectively). The ventricular volume percentage was an excellent parameter for evaluating the degree of hydrocephalus (area under the receiver operating characteristic curve = 0.975; 95% confidence interval, 0.948–1.000; p < 0.001). With a cut-off value of 2.4%, the diagnosis of unchanged hydrocephalus could be made with 83.0% sensitivity and 100.0% specificity.ConclusionThe ventricular volume percentage quantified using 3D brain CT data is useful for interpreting serial changes in hydrocephalus.

Comparison of the performance between Frontier ASPECTS software and different levels of radiologists on assessing CT examinations of acute ischaemic stroke patients

To compare the performance of Frontier Alberta Stroke Program Early CT Score (ASPECTS) software with different levels of radiologists in assessing computed tomography (CT) examinations of patients with early acute ischaemic stroke (AIS), and to evaluate whether this software can improve the performance of rating by less experienced radiologists. Unenhanced brain CT examinations of 55 patients with acute middle cerebral artery ischaemia were scored separately by Frontier, two senior radiologists, and two junior radiologists retrospectively and blinded to any clinical information. Two junior radiologists then scored again with the assist of Frontier. The reference standard was defined as the ASPECTS on Follow-up unenhanced CT scored by another two non-blinded independent experts on a consensus basis. Statistical analysis was performed using intraclass correlation coefficient (ICC) analysis and Bland-Altman plots. Frontier and senior radiologists in ASPECTS reading have excellent agreement with the reference standard (r=0.842 and 0.803, respectively), while only a good agreement was found between junior radiologists and reference standard (r=0.680). Bland-Altman analysis revealed the mean ASPECTS difference and SD difference of junior radiologists were larger (mean difference=1.35; SD=1.42) than that of Frontier and senior radiologists with reference standard (mean difference=0.16, 0.22; SD=1.24, 1.13, respectively). However, with the assist of Frontier, the agreement between junior radiologists and reference standard was improved from good (r=0.680) to excellent (r =0.852), and the mean ASPECTS difference and SD difference were reduced. High agreement in ASPECTS rating between senior radiologists, Frontier, and expert consensus reading was found. Moreover, Frontier can improve the performance of less experienced radiologists to assess the ASPECTS of patients with AIS.

Radiation doses with various body weights of phantoms in brain 128-slice MDCT examination.

The effective dose (HE) and organ or tissue equivalent dose (HT) for use in brain computed tomography (CT) examinations with various body weights were evaluated. Thermoluminescent dosimeters (TLD-100H) were inserted into Rando and five anthropomorphic phantoms. These phantoms were made of polymethylmethacrylate (PMMA), according to the specifications of ICRU 48, with masses from 10 to 90 kg. Brain CT examinations were conducted, scanning the maxillae from the external auditory meatus to the parietal bone using a 128-slice multi-detector CT (MDCT) scanner. To reduce errors, three independent trials were conducted. Calculated HE,TLD, based on the weighting factor recommended by ICRP 103, was 1.72 ± 0.28 mSv, which slightly exceeds the HE,DLP of 1.70 mSv, that was calculated from the dose–length product (DLP) of the Rando phantom. This experiment yielded HE,TLD values of ICRP 103 from the highest 1.85 ± 0.28 (90 kg) to the lowest 1.47 ± 0.22 (10 kg) mSv. HE,TLD (mSv) = 5.45×10−3 W(kg) + 1.361, with an R2 of 0.87667. Using the DLP protocol, HE,DLP was estimated from CTDIvol that was recorded directly from the console display of the CT unit and multiplied by the conversion coefficient (k) recommended by the ICRP 103. Finally, the experimental results obtained herein are compared with those in the literature. Physicians should choose and adjust protocols to prevent the exposure of patients to unnecessary radiation, satisfying the as low as reasonably achievable (ALARA) principle. These findings will be valuable to patients, physicians, radiologists and the public.

DIRECT MEASUREMENTS OF SKIN, EYE LENS AND THYROID DOSE DURING PEDIATRIC BRAIN CT EXAMINATIONS

Pediatric brain computed tomography (CT) is identified as the most frequent CT examination in children. The aim of the study is the direct measurement of skin, eye lens and thyroid dose in pediatric patients during brain CT examinations. The study included 35 pediatric patients who underwent brain CT examinations. The patients were categorized in three age groups: Group A (age range: 0.8-1 years), Group B (age range: 2.0-4.9 years) and Group C (age range: 5.5-15.5 years). thermoluminescent dosimeters (TLDs) were placed on the eyes, the frontal region of the head, the mastoid apophysis and the thyroid gland. The skin dose was found 16.6 ± 1.5, 38.8 ± 5.1 and 41.7 ± 9.4 mGy for Groups A, B and C, respectively. The mean dose for the eye lens was 10.5 ± 3.3, 29.9 ± 8.6 and 34.2 ± 14.9 mGy and for the thyroid 1.7 ± 0.4, 2.4 ± 0.5 and 1.9 ± 0.4 mGy for Groups A, B and C, respectively. In vivo dosimetry using TLDs proved to be an efficient method. Gantry tilting and patient's set-up seem to significantly affect eye lens dose.

Quality Criteria Implementation for Brain Computed Tomography Examinations

The main aim of this study was to implement the quality criteria proposed by the European Commission for brain computed tomography (CT) examinations. The proposed criteria were evaluated for 102 brain CT examinations, with a special emphasis on the diagnostic and radiation dose requirements. The examinations were elected at random from brain examinations performed tiler a period of a month at eight scanners of the CT Pace range. Achievement of image criteria was evaluated by two independent observers. The most important preliminary findings concerning image criteria fulfilment or lack of it and disagreements between observers are presented and discussed. The mean values of the proposed dosimetric quantities are compared to the reference values. The examinations performed with and without injection of a contrast agent are also analysed in relation to dosimetric quantities and criteria fulfilment.