Computed Tomography Protocol Research Articles

Establishment of diagnostic reference level and radiation dose variation in head & neck and pelvis treatment planning in radiation therapy computed tomography

Background: This observational study aims to establish a discrepancy in the radiation dose distributed for head & neck and pelvis localization in Computed Tomography (CT) imaging in radiation therapy. The objective and need of the current study are to establish Diagnostic Reference Level (DRL) for head & neck and pelvic CT protocols in Radiation Therapy planning and compare them with other regional, national and international DRL. The established DRL will be used to find further optimized DRL for Radiation Therapy Computed Tomography (RTCT). Methods: A total of 120 patients with Head & Neck cancers and 90 patients with pelvic cancers to be treated with radiotherapy prescribed for the RTCT with ages above 18 years old and above were included in the current study. The advanced Philips 16 slice big bore CT acquired all the CT simulation images. Results: Third quartile standards of Dose Length Product and effective dose for Head & Neck, and pelvis were 790.65mGy.cm, 2.45179 mSv, and 999.7 mGy.cm, 15.48mSv respectively. The third quartile CTDIvol value for the same order of procedure is 17.6 mGy. Tube voltage of 120kVp and 300mAs and used for radiotherapy planning. Conclusion: The first regional Radiation therapy Computed tomography simulation Diagnostic reference levels have been projected and deliver a platform for dose evaluation and optimization due to the limited number of papers on radiation therapy, computed tomography, and diagnostic reference levels. Comparison with previously available RT CT diagnostic reference levels indicated some radiation dose variation, so exposure parameters should be revised and improved.

Changes in the organs of the gastrointestinal tract in a new coronavirus infection (COVID-19): computed tomography semiotics

Introduction. A new coronavirus infection (COVID-19) is a pathogenetically complex disease characterized by the involvement of the main human organs and systems in the pathological process, including the organs of the gastrointestinal tract (gastrointestinal tract).Purpose: to study the gastroenterological manifestations of COVID-19 in patients of mild and moderate severity based on the analysis of complex data, including computed tomography examination.Material and methods. The study included 80 patients hospitalized with a confirmed diagnosis of COVID-19 (19 patients with mild and 61 with moderate severity) who underwent a comprehensive original examination upon admission to the hospital and outpatient at week 8 of dynamic follow-up. In the complex therapy of 41 patients, the drug rebamipid was used. The scope of the examination included questionnaires, traditional clinical, clinical and laboratory, biochemical, instrumental and radiation studies, unique methods for studying microbiota and intestinal permeability. All patients also underwent computed tomography (CT) of the chest organs, followed by analysis and postprocessing of images of the upper abdominal cavity. The study also included a group of 43 inpatient patients with moderate severity of the disease, a group of 17 practically healthy patients was used as a control.Results and conclusions. A method of qualitative and quantitative assessment of the state of parenchymal and hollow organs of the upper abdominal cavity according to CT data is proposed. It was found that with moderate severity of COVID-19, quantitative criteria (attenuation coefficient of the liver, pancreas, bile) were subject to more pronounced deviations, as was the diameter of the colon. Additional diagnostic capabilities of the standard chest CT protocol in patients with COVID-19 are associated with postprocessor analysis of images of abdominal organs.

Editor's Choice – Structured Computed Tomography Analysis can Identify the Majority of Patients at Risk of Post-Endovascular Aortic Repair Rupture

The main objective was to report mechanisms and precursors for post-endovascular aneurysm repair (EVAR) rupture. The second was to apply a structured protocol to explore whether these factors were identifiable on follow up computed tomography (CT) prior to rupture. The third objective was to study the incidence, treatment, and outcome of post-EVAR rupture. This was a multicentre, retrospective study of patients treated with standard EVAR at five Swedish hospitals from 2008 to 2018. Patients were identified from the Swedvasc registry. Medical records were reviewed up to 2020. Index EVAR and follow up data were recorded. The primary endpoint was post-EVAR rupture. CT at follow up and at post-EVAR rupture were studied, using a structured protocol, to determine rupture mechanisms and identifiable precursors. In 1 805 patients treated by EVAR, 45 post-EVAR ruptures occurred in 43 patients. The cumulative incidence was 2.5% over a mean follow up of 5.2 years. The incidence rate was 4.5/1 000 person years. Median time to post-EVAR rupture was 4.1 years. A further six cases of post-EVAR rupture in five patients found outside the main cohort were included in the analysis of rupture mechanisms only. The rupture mechanism was type IA in 20 of 51 cases (39%), IB in 20 of 51 (39%) and IIIA/B in 11 of 51 (22%). One of these had type IA+ IB combined. One patient had an aortoduodenal fistula without another mechanism being identified. Precursors had been noted on CT follow up prior to post-EVAR rupture in 16 of 51 (31%). Retrospectively, using the structured protocol, precursors could be identified in 43 of 51 (84%). In 17 of 27 (63%) cases missed on follow up but retrospectively identifiable, the mechanisms were type IB/III. Overall, the 30 day mortality rate after post-EVAR rupture was 47% (n= 24/51) and the post-operative mortality rate was 21% (n= 7/33). Most precursors of post-EVAR rupture are underdiagnosed but identifiable before rupture using a structured follow up CT protocol. Precursors of type IB and III failures caused the majority of post-EVAR ruptures.

Establishment of diagnostic reference level and radiation dose variation in head & neck and pelvis treatment planning in radiation therapy computed tomography

Background: This observational study aims to establish a discrepancy in the radiation dose distributed for head & neck and pelvis localization in Computed Tomography (CT) imaging in radiation therapy. The objective and need of the current study are to establish Diagnostic Reference Level (DRL) for head & neck and pelvic CT protocols in Radiation Therapy planning and compare them with other regional, national and international DRL. The established DRL will be used to find further optimized DRL for Radiation Therapy Computed Tomography (RTCT). Methods: A total of 120 patients with Head & Neck cancers and 90 patients with pelvic cancers to be treated with radiotherapy prescribed for the RTCT with ages above 18 years old and above were included in the current study. The advanced Philips 16 slice big bore CT acquired all the CT simulation images. Results: Third quartile standards of Dose Length Product and effective dose for Head & Neck, and pelvis were 790.65mGy.cm, 2.45179 mSv, and 999.7 mGy.cm, 15.48mSv respectively. The third quartile CTDIvol value for the same order of procedure is 17.6 mGy. Tube voltage of 120kVp and 300mAs and used for radiotherapy planning. Conclusion: The first regional Radiation therapy Computed tomography simulation Diagnostic reference levels have been projected and deliver a platform for dose evaluation and optimization due to the limited number of papers on radiation therapy, computed tomography, and diagnostic reference levels. Comparison with previously available RT CT diagnostic reference levels indicated some radiation dose variation, so exposure parameters should be revised and improved.

Detection of Incidental Nonosseous Thoracic Pathology on State-of-the-Art Ultralow-Dose Protocol Computed Tomography in Pediatric Patients With Pectus Excavatum.

The aim of the study was to compare a pediatric ultralow-dose pectus excavatum computed tomography (CT) protocol versus standard-dose pediatric thoracic CT in terms of radiation dose, subjective and objective image quality, and its ability to detect incidental nonosseous thoracic pathology compared with imaging and clinical reference. A single institution radiology database identified a total of 104 ultralow-dose pediatric thoracic CT cases with an equal number of age-matched standard-dose chest CT cases also selected for retrospective analysis. Objective image quality (contrast-to-noise and signal-to-noise ratios) and radiation dose were assessed. Qualitative Likert scorings of the bone, lung, and soft tissues were performed by 2 expert radiologists. Electronic health records of the ultralow-dose cohort were reviewed for at least 1 year to evaluate for potentially missed thoracic pathology and symptoms. Variables were compared using parametric and nonparametric tests in R software 4.0.5. The ultralow-dose protocol group had statistically significant reductions (P < 0.001) in the volume CT dose index (0.31 ± 0.19 vs 2.20 ± 1.64 mGy), effective radiation dose (0.14 ± 0.08 vs 1.07 ± 0.86 mSv), and size-specific dose estimates (0.50 ± 0.30 vs 3.43 ± 2.56 mGy) compared with the standard protocol, yielding an 86.51% and 85.32% reduction, respectively. The signal-to-noise ratio (20.49 ± 6.19 vs 36.48 ± 10.20), contrast-to-noise (21.65 ± 6.57 vs 38.47 ± 10.59), and subjective measures of image quality (lung parenchyma [3.07 ± 0.92 vs 4.42 ± 0.47], bony structures [3.30 ± 0.86 vs 4.52 ± 0.51], and surrounding soft tissues [2.57 ± 0.63 vs 3.89 ± 0.65]) were also significantly lower in the ultralow-dose protocol (P < 0.001). No differences were seen in the number and size of pulmonary nodules between groups. Clinical and imaging follow of all 104 patients undergoing ultralow-dose CT demonstrated no evidence of missed thoracic pathology causing symptoms. Ultralow-dose thoracic CT is an acceptable modality for imaging pediatric patients with pectus excavatum and other conditions primarily causing osseous pathology, with effective radiation dose comparable to plain radiographs and a moderate increase in image noise that did not significantly reduce its ability to detect incidental nonosseous thoracic pathology.

Glenoid Version Assessment When the CT Field of View Does Not Permit the Friedman Method: The Robertson Method.

Background:To improve spatial resolution, current clinical shoulder cross-sectional imaging studies reduce the field of view of the shoulder, excluding the medial scapula border and preventing glenoid version measurement according to the Friedman method.Purpose:To evaluate a method to accurately and reliably measure glenoid version on cross-sectional shoulder images when the medial scapula border is not included in the field of view, and to establish measurements equivalent to the Friedman method.Study Design:Controlled laboratory study.Methods:Sixty-five scapulae underwent computed tomography (CT) scanning with an optimal shoulder CT-positioning protocol. Glenoid version was measured on CT images of the full scapula using the Friedman method. We developed a measurement method (named the Robertson method) based on the glenoid vault version from partial scapula images, with a correction angle subtracted from the articular-surface-glenoid vault measurement. Comparison with the Friedman method defined the accuracy of the Robertson method. Three observers tested inter- and intraobserver reliability of the Robertson method. Accuracy was statistically evaluated with t tests and reliability with the intraclass correlation coefficient (ICC).Results:The statistical distribution of glenoid version was similar to published data,–0.5° ± 3° [mean ± SD]. The initial measurement using the Robertson method resulted in a more retroverted angle compared with the Friedman method, and a correction angle of 7° was then applied. After this adjustment, the difference between the 2 methods was nonsignificant (0.1° ± 4°; P > .65). Reliability of the Robertson method was excellent, as the interrater ICC was 0.77, the standard error of measurement (SEM) was 1.1° with P < .001. The intrarater ICC ranged between 0.84 and 0.92, the SEM ranged between 0.9° and 1.2° with P < .01.Conclusion:A validated glenoid version measurement method is now available for current clinical shoulder CT protocols that reliably create Friedman-equivalent values.Clinical Relevance:Friedman-equivalent values may be made from common clinical CTs of the shoulder and compared with prior and future Friedman measurements of the scapula.

Thoracic non-traumatic cardiovascular diseases: current perspective and multi-detectors Computed Tomography protocols optimization in the emergency setting.

Cardiovascular diseases (CVDs) are among the most common causes of access to the Emergency Department and among the leading causes of death worldwide. Accurate diagnostic algorithms are mandatory to ensure a rapid life-saving treatment. However, non-specific clinical presentation and unnecessary referrals to other subspecialties may lead to misinterpretation of the diagnosis and delays. In recent years, the development of imaging technologies has allowed Computed Tomography (CT) to play a prominent role in the concepts of CVD rule-in and rule-out. An optimization strategy for CT protocols is needed to reduce variability and improve image quality. A correct diagnostic suspicion is crucial, as different districts (i.e., heart, aorta and pulmonary circulation) may require different investigation techniques. Additionally, the CVD pre-test probability assessment is highly correlated with CT accuracy. The purpose of this narrative review is to analyze the current role of CT in the approach to the CVDs in the ED, and to analyze the main strategies of CT optimization.

In vitro measurements of radiation exposure with different modalities (computed tomography, cone beam computed tomography) for imaging the petrous bone with a pediatric anthropomorphic phantom

BackgroundVarious imaging modalities, such as multi-detector computed tomography (CT) and cone beam CT are commonly used in infants for the diagnosis of hearing loss and surgical planning of implantation hearing aid devices, with differing results.ObjectiveWe compared three different imaging modalities available in our institution, including a high-class CT scanner, a mid-class CT scanner and an angiography system with a cone beam CT option, for image quality and radiation exposure in a phantom study.Materials and methodsWhile scanning an anthropomorphic phantom imitating a 1-year-old child with vendor-provided routine protocols, organ doses, surface doses and effective doses were determined for these three modalities with thermoluminescent dosimeters. The image quality was evaluated using the signal difference to noise ratio (SDNR) and the spatial resolution of a line-pair insert in the phantom head. The dose efficiency, defined as the ratio of SDNR and effective dose, was also compared.ResultsThe organ and surface doses were lowest with the high-class CT protocol, but the image quality was the worst. Image quality was best with the cone beam CT protocol, which, however, had the highest radiation exposure in this study, whereas the mid-class CT was in between.ConclusionBased on our results, high-end CT should be used for surgical planning because it has the lowest dose, while the image quality is still sufficient for this purpose. However, if highest image quality is needed and required, e.g., by ENT surgeons, the other modalities should be considered.

PixelPrint: Three-dimensional printing of realistic patient-specific lung phantoms for CT imaging.

Phantoms are essential tools for assessing and verifying performance in computed tomography (CT). Realistic patient-based lung phantoms that accurately represent textures and densities are essential in developing and evaluating novel CT hardware and software. This study introduces PixelPrint, a 3D-printing solution to create patient-specific lung phantoms with accurate contrast and textures. PixelPrint converts patient images directly into printer instructions, where density is modeled as the ratio of filament to voxel volume to emulate local attenuation values. For evaluation of PixelPrint, phantoms based on four COVID-19 pneumonia patients were manufactured and scanned with the original (clinical) CT scanners and protocols. Density and geometrical accuracies between phantom and patient images were evaluated for various anatomical features in the lung, and a radiomic feature comparison was performed for mild, moderate, and severe COVID-19 pneumonia patient-based phantoms. Qualitatively, CT images of the patient-based phantoms closely resemble the original CT images, both in texture and contrast levels, with clearly visible vascular and parenchymal structures. Regions-of-interest (ROIs) comparing attenuation demonstrated differences below 15 HU. Manual size measurements performed by an experienced thoracic radiologist revealed a high degree of geometrical correlation between identical patient and phantom features, with differences smaller than the intrinsic spatial resolution of the images. Radiomic feature analysis revealed high correspondence, with correlations of 0.95-0.99 between patient and phantom images. Our study demonstrates the feasibility of 3D-printed patient-based lung phantoms with accurate geometry, texture, and contrast that will enable protocol optimization, CT research and development advancements, and generation of ground-truth datasets for radiomic evaluations.

The use of contrast enhanced thoraco-abdominal CT in patients with non-traumatic undifferentiated hemodynamic shock

ObjectiveTo assess the role of thoraco-abdominal computed tomography (CT) in patients with undifferentiated shock in the emergency department (ED). Secondary aim was to assess common etiologies for undifferentiated shock. MethodsThis was a single-center, retrospective study evaluating patients with undifferentiated shock who underwent a dedicated “shock protocol” CT in the ED. CT included a non-contrast thoraco-abdominal scan followed by arterial thoraco-abdominal and abdominal portal phases. Patients' clinical records, laboratory, imaging data and all-cause 90-days mortality were collected. Patients’ shock category (i.e., distributive, cardiogenic, hypovolemic, obstructive, multifactorial, and unknown) and etiology for shock were retrospectively determined based on patients’ medical records. Effect of CT on patients' diagnosis and management was assessed based on physicians' reports before and after CT. ResultsOverall, 102 patients were scanned between December 2018 and December 2020. Distributive shock was the most prevalent type with 47.1% of all patients (48/102), followed by hypovolemic shock (17/102, 16.7%). Based on clinical data and CT reports, shock etiology was diagnosed for 89.2% (91/102) patients. Sepsis was the most common etiology in 50% of patients, followed by non-traumatic hemorrhage (15/102, 14.7%). Overall, 90-day mortality was 58.8%. Shock protocol CT led to change in differential diagnosis in 49% of patients and to change in management in 42.2%. ConclusionContrast-enhanced shock protocol CT can help in shock differentiation, assessment of etiology and in management of patients presenting to the ED with undifferentiated shock.

Optimization of CT protocol in polytrauma patients: an update.

Radiologists play a key role in the management of trauma patients. With the improvement of computed tomography (CT), radiologist makes an important contribution to the timely diagnosis of trauma-related findings and the choice of the most suitable treatment, improving patient outcomes. It is important to select the most appropriate imaging technique, which in the trauma patient is CT, and especially the most appropriate CT protocol, to correctly characterize trauma injuries. Currently, there is no agreement on what the optimal protocol is, acquisition times and number of contrast enhanced phases are not standardized. This is a review of the most recent literature on optimizing the CT protocol in polytrauma, with the intent of giving a useful tool for radiologists in the management of trauma patients.

An analysis of trauma-related CT utilization and abnormal findings in emergency department: a one-year retrospective study

Trauma is one of the major indications for admission to the emergency department (ED) and Computed Tomography (CT) scan requests. Understanding of CT utilization is important to reduce unnecessary imaging and radiation exposure. This study aimed to examine the utilization pattern of CT scans for trauma patients in the ED and how often traumatic abnormalities occurred. A retrospective study was conducted over a one-year period. Data for patients who were admitted to the ED and underwent CT scans for trauma indications, type of CT procedure performed, findings, and prior radiography were collected from the picture archiving and communication system. A total of 881 trauma patients underwent a CT scan as part of their investigation. Abnormalities were identified in 527 (59.9%) of cases and proportional with prior radiography [828 (94%)]. Different types of CT procedures were performed, as requested by the ED physicians, including 450 CT scans of the head, 188 for the spine, 93 for the chest, 45 CT CAP, 29 for the whole-body, 22 for the pelvis, 16 for the chest and abdomen, 13 for the extremities, and 11 for the abdomen. CT of the head was the most common procedure performed for trauma patients with 55% positive findings and may represent an opportunity for reduction of the use of CT scans, taking into consideration validated clinical decision rules. For multiple-trauma patients, a clearly defined criterion must be established to determine which CT procedure is required for these patients based on clinical indications and presentations. Therefore, for better radiation protection practices, a review and improvement of CT protocols, as well as justification and optimization, should be considered for utilization of CT scans for trauma patients.

Radiation dose and image quality in abdominal CT: Phantom Study

The purpose of this study was to evaluate and compare the effect of acquisition parameters of the abdominal computed tomography protocol on image quality and dose quantities, including contrast-to-noise ratio (CNR), noise, spatial resolution (SR) as well as volumetric computed tomography dose index (CTDIv).&#x0D; The measurements have been done on a HITACHI 16-slice scanner using two phantoms (PMMA and Catphan 500), two tube voltages of 120KVp and 100KVp have been analyzed while varying the tube current settings from 155 to 300 (mAs) in order to measure the abdominal image quality quantities and dose (CTDIv).&#x0D; The scanning at 100KVp compared to 120KVp has resulted in a dose reduction up to 38% at mAs ranging from 100 to 300, a decrease in CNR of 28%, a slight decrease in spatial resolution accompanied with an increase in noise.&#x0D; This study has shown that despite the increase in noise at low tube voltages, it is possible to reduce the dose without affecting the quantities of spatial resolution and the contrast/noise ratio by lowering the tube voltage from 120KVp to 100KVp.&#x0D; Keywords: Abdominal CT; CTDIv; Image Quality; Phantom.

Low-dose CT with tin filter combined with iterative metal artefact reduction for guiding lung biopsy.

Computed tomography (CT) is currently the imaging modality of choice for guiding pulmonary percutaneous procedures. The use of a tin filter allows low-energy photons to be absorbed which contribute little to image quality but increases the radiation dose that a patient receives. Iterative metal artefact reduction (iMAR) was developed to diminish metal artefacts. This study investigated the impact of using tin filtration combined with an iMAR algorithm on dose reduction and image quality in CT-guided lung biopsy. Ninety-nine consecutive patients undergoing CT-guided lung biopsy were randomly assigned to routine-dose CT protocols (groups A and B; without and with iMAR, respectively) or tin filter CT protocols (groups C and D; without or with iMAR, respectively). Subjective image quality was analysed using a 5-point Likert scale. Objective image quality was assessed, and the noise, contrast-to-noise ratio, and figure of merit were compared among the four groups. Metal artefacts were quantified using CT number reduction and metal diameter blurring. The radiation doses, diagnostic performance, and complication rates were also estimated. The subjective image quality of the two scan types was compared. Images with iMAR reconstruction were superior to those without iMAR reconstruction (group A: 3.49±0.65 vs. group B: 4.63±0.57; P<0.001, and group C: 3.88±0.66 vs. group D: 4.82±0.39; P<0.001). Images taken with a tin filter were found to have a significantly higher figure-of-merit than those taken without a tin filter (group A: 14,041±7,230 vs. group C: 21,866±10,656; P=0.001, and group B: 13,836±6,849 vs. group D: 21,639±9,964; P=0.001). In terms of metal artefact reduction, tin filtration combined with iMAR showed the lowest CT number reduction (116.62±103.48 HU) and metal diameter blurring (0.85±0.30) among the protocols. The effective radiation dose in the tin filter groups was 73.2% lower than that in the routine-dose groups. The complication rate and diagnostic performance (sensitivity, specificity, and overall accuracy) did not differ significantly between the tin filter and routine-dose groups (all P>0.05). Tin filtration combined with an iMAR algorithm may reduce the radiation dose compared to the routine-dose CT protocol, while maintaining comparable diagnostic accuracy and image quality and producing fewer metal artefacts.

Optimized Computed Tomography Acquisition Protocol for Ethanol Infusion Into the Vein of Marshall.

This study sought to introduce a computed tomography (CT) protocol for optimal planning of vein of Marshall (VOM) catheterization. Ethanol infusion into the VOM (Et-VOM) is increasingly used in atrial fibrillation ablation. Preprocedural CT was performed with either a conventional (conv-CT; n=132) or an optimized CT protocol (VOM-CT; n=126) designed for obtaining on a single image both left atrial and coronary sinus (CS) enhancement. The detection rate and anatomical features of the CT-derived VOM were analyzed and the utility of VOM-CT protocol was assessed by comparing the procedural data. VOM was detected in 35% in conv-CT versus 63% in VOM-CT (P< 0.001). The VOM-CT protocol did not impair the assessment of left atrial anatomy and appendage patency. In VOM-CT, the detection of the VOM was related to body mass index and width of epicardial space on posterior wall. Mean distance between CS ostium and VOM was 36±7mm. Mean VOM diameter was 1.6 ± 0.3mm. On the CS circumference, the VOM emerged superiorly in 68% and postero-superiorly in 32%. Ethanol infusion into the VOM was attempted in 165 patients (77 conv-CT, 70 VOM-CT, and 18 without-CT). After registration in CARTO, the VOM segmented on CT matched its location on venography in all cases. As compared with conv-CT and without-CT, procedures guided by VOM-CT showed significantly shorter radiation time, shorter procedure time, lower amount of the contrast medium, and fewer contrast injections to obtain VOM catheterization. The proposed CT protocol allows for improved visualization of the VOM, translating into easier VOM catheterization.

Structural similarity analysis of midfacial fractures-a feasibility study.

The structural similarity index metric is used to measure the similarity between two images. The aim here was to study the feasibility of this metric to measure the structural similarity and fracture characteristics of midfacial fractures in computed tomography (CT) datasets following radiation dose reduction, iterative reconstruction (IR) and deep learning reconstruction. Zygomaticomaxillary fractures were inflicted on four human cadaver specimen and scanned with standard and low dose CT protocols. Datasets were reconstructed using varying strengths of IR and the subsequently applying the PixelShine™ deep learning algorithm as post processing. Individual small and non-dislocated fractures were selected for the data analysis. After attenuating the osseous anatomy of interest, registration was performed to superimpose the datasets and subsequently to measure by structural image quality. Changes to the fracture characteristics were measured by comparing each fracture to the mirrored contralateral anatomy. Twelve fracture locations were included in the data analysis. The most structural image quality changes occurred with radiation dose reduction (0.980036±0.011904), whilst the effects of IR strength (0.995399±0.001059) and the deep learning algorithm (0.999996±0.000002) were small. Radiation dose reduction and IR strength tended to affect the fracture characteristics. Both the structural image quality and fracture characteristics were not affected by the use of the deep learning algorithm. In conclusion, evidence is provided for the feasibility of using the structural similarity index metric for the analysis of structural image quality and fracture characteristics.

Study the difference between the measurement of the radiation dose of MRI and CT scan

Radiation dose or absorbed dose means that the amount of energy absorbed by human tissue, and accurately is the concentration of energy deposited in tissue, when exposure to ionizing radiation, effective dose is the dose that will achieve the desired effect its unit is (millisievert or mSv). Ionizing radiation used in computed tomography (CT) scans as well as the associated health risks are an ongoing and growing concern.&#x0D; The aim of this study is to prove the use of X-rays and computed tomography with a small dose of ionizing radiation to produce images for medical examination.&#x0D; An MRI scan uses powerful magnets and radio waves to create images instead of ionizing radiation. Therefore, you are not exposed to radiation when you have an MRI scan, unlike a CT scan or X-ray. In addition to reducing the examination time and cost.&#x0D; Material and methods show that individual doses measured for a routine whole-body CT protocol are less than 20 mGy for all parts of the body. Thus, we conclude that the measured doses of the external organs are higher than those in the internal organs under the same conditions that are exposed to radiation Knowing that MRI does not use radiation (such as X-rays or CT scans) there are more MRI machines being produced from several companies around the world.&#x0D; Knowing that MRI does not use radiation (such as X-rays or CT scans) there are more MRI machines being produced from several companies around the world.&#x0D; Result in this study, it was done evaluate the benefits of MRI and CT in diagnoses and treatment as well as for their side effects, at present and in the future.Conclusions. We have also concluded that CT is specific in certain areas of the human body such as the lungs and abdominal area and identify the areas of bone fractures, and magnetic resonance (MRI) gives us excellent image of high-definition of the spinal cord, brain and membranes, and the areas of the joints with animated images and a three - dimensional and in a record time of 15-30 minutes.&#x0D; Where the diagnosis could be re-diagnosed during the procedure and after the occurrence of any side effects, unlike the tomography, which is specified in certain cases mentioned earlier, and a period of time of 5-10 minutes and cannot be returned except in special cases forced to have the effect of radiation. The final conclusion of our work, which is not only important in diagnosing, is that in the case of CT, there are no disturbing sounds and the presence of an area in which the patient can settle, unlike magnetic resonance imaging, Where the annoying resonance sounds are added to the narrowness and smallness of the place where the patient is located, but they are not considered to be of medical importance.

Inter-Observer Agreement between Low-Dose and Standard-Dose CT with Soft and Sharp Convolution Kernels in COVID-19 Pneumonia.

Computed tomography (CT) has been an essential diagnostic tool during the COVID-19 pandemic. The study aimed to develop an optimal CT protocol in terms of safety and reliability. For this, we assessed the inter-observer agreement between CT and low-dose CT (LDCT) with soft and sharp kernels using a semi-quantitative severity scale in a prospective study (Moscow, Russia). Two consecutive scans with CT and LDCT were performed in a single visit. Reading was performed by ten radiologists with 3–25 years’ experience. The study included 230 patients, and statistical analysis showed LDCT with a sharp kernel as the most reliable protocol (percentage agreement 74.35 ± 43.77%), but its advantage was marginal. There was no significant correlation between radiologists’ experience and average percentage agreement for all four evaluated protocols. Regarding the radiation exposure, CTDIvol was 3.6 ± 0.64 times lower for LDCT. In conclusion, CT and LDCT with soft and sharp reconstructions are equally reliable for COVID-19 reporting using the “CT 0-4” scale. The LDCT protocol allows for a significant decrease in radiation exposure but may be restricted by body mass index.

Current Standards for and Clinical Impact of Emergency Radiology in Major Trauma.

In industrialized countries, high energy trauma represents the leading cause of death and disability among people under 35 years of age. The two leading causes of mortality are neurological injuries and bleeding. Clinical evaluation is often unreliable in determining if, when and where injuries should be treated. Traditionally, surgery was the mainstay for assessment of injuries but advances in imaging techniques, particularly in computed tomography (CT), have contributed in progressively changing the classic clinical paradigm for major traumas, better defining the indications for surgery. Actually, the vast majority of traumas are now treated nonoperatively with a significant reduction in morbidity and mortality compared to the past. In this sense, another crucial point is the advent of interventional radiology (IR) in the treatment of vascular injuries after blunt trauma. IR enables the most effective nonoperative treatment of all vascular injuries. Indications for IR depend on the CT evidence of vascular injuries and, therefore, a robust CT protocol and the radiologist’s expertise are crucial. Emergency and IR radiologists form an integral part of the trauma team and are crucial for tailored management of traumatic injuries.

Impact of dose reduction and iterative reconstruction algorithm on the detectability of pulmonary nodules by artificial intelligence

PurposeThe purpose of this study was to assess whether the performances of an automated software for lung nodule detection with computed tomography (CT) are affected by radiation dose and the use of iterative reconstruction algorithm. Materials and methodsA chest phantom (Multipurpose Chest Phantom N1; Kyoto Kagaku Co. Ltd, Kyoto, Japan) with 15 pulmonary nodules was scanned with a total of five CT protocol settings with up to 20-fold dose reduction. All CT examinations were reconstructed with iterative reconstruction algorithms ADMIRE 3 and ADMIRE 5 and were then analyzed for the presence of pulmonary nodules with a fully automated computer aided detection software system (InferReadTM CT Lung, Infervision), which is based on deep neural networks. ResultsThe sensitivity of fully automated pulmonary nodule detection for ground-glass nodules at standard dose CT was greater (70.0%; 14/20; 95% CI: 51.6-88.4%) than at 10-fold and 20-fold dose reduction (30.0%; 6/20; 95% CI: 0.0%-62.5%). There were less false positive findings when ADMIRE 5 reconstruction was used (4.0 ± 2.8 [SD]; range: 2–6) instead of ADMIRE 3 reconstruction (25.0 ± 15.6 [SD]; range: 14–36). There was no difference in the sensitivity of detection of solid and subsolid nodules between standard dose (100%; 95% CI: 100–100%) and 10- and 20-fold reduced dose CT (92.5%; 95% CI: 83.8–100.0%). Image noise was significantly greater with ADMIRE 3 (81 ± 2 [SD] [range: 79–84]; 104 ± 3 [SD] [range: 101–107]; 114 ± 5 [SD] [range: 110–119]; 193 ± 10 [SD] [range: 183-203]; 220 ± 16 [SD] [range: 210–238]) compared to ADMIRE 5 (44 ± 2 [SD] [range: 42–46]; 60 ± 2 [SD] [range: 57–61]; 66 ± 1 [SD] [range: 65–67]; 103 ± 4 [SD] [range: 98–106]; 110 ± 1 [SD] [range: 109–111]), respectively in each of the five CT protocols. ConclusionThis phantom study suggests that dose reduction and iterative reconstruction settings have an impact on detectability of pulmonary nodules by artificial intelligence software and we therefore encourage adaption of dose levels and reconstruction methods prior to widespread implementation of fully automatic nodule detection software for lung cancer screening purposes.