Routine Computed Tomography Research Articles

Feasibility of size-specific organ-dose estimates based on water equivalent diameter for common head CT examinations: a Monte Carlo study

Computed tomography dose index (CTDI) is an unreliable dose estimate outside of the standard CTDI phantom diameters (16 and 32 cm). Size-specific dose estimate (SSDE) for head computed tomography (CT) examination was studied in the American Association of Physicists in Medicine Report 293 to provide SSDE coefficient factors based on water equivalent diameter as size metrics. However, it is limited to one protocol and for a fully irradiated organ. This study aimed to evaluate the dependency of normalized organ dose (ND) on water equivalent diameter as a size metric in three common protocols: routine head, paranasal sinus, and temporal bone. CTDIw measurements were performed for outlined protocols in the Siemens Emotion 16-slice-configuration scanner. Geant4 Application for Tomographic Emission Monte Carlo simulation platform, coupled with ten GSF patient models, was used to estimate organ doses. CT scanner system was modeled. Helical CT scans were simulated using constructor scan parameters and calculated scan lengths of each patient model. Organ doses provided by simulations were normalized to CTDIvol. The water equivalent diameters (D w) of patient models were obtained via relationships between D w and both effective diameter for a sample of patients’ data.NDs received by fully, partially, and non-directly irradiated organs were then reported as a function of D w. For fully irradiated organs, brain (R 2 > 0.92), eyes (R 2 > 0.88), and eye lens (R 2 > 0.89) correlate well with D w. For the rest of the results, a poor correlation was observed. For partially irradiated organs, the exception was scalp (R 2 = 0.93) in temporal bone CT. For non-directly irradiated organs, the exception was thyroid (R 2 > 0.90) and lungs (R 2 > 0.91) in routine head CT. ND correlates well in routine head CT than other protocols. For the most part, no relationship seems to exist between R 2 and scan percentage coverage. The results have revealed additional factors that may influence the ND and D w relationship, which explains the need for more studies in the future to investigate the effect of scan conditions and organ anatomy variation.

A Retrospective Study on Traumatic Elbow Dislocation in Adults in a Tertiary Hospital in Riyadh, Saudi Arabia.

Background This retrospective chart review aimed to ascertain the frequency and characteristics of radial head fractures in adults who presented to our emergency department with elbow dislocation. Methodology This study was conducted in a single tertiary trauma center in Riyadh, Saudi Arabia, between July 2015 and July 2020 to identify traumatic elbow dislocation in adults. Patients were identified after thoroughly examining the hospital's electronic X-ray database. In addition, computed tomography (CT) was used to assess complete ulnohumeral joint dislocation. In total, 80 patients between the ages of 18 and 65 were evaluated for a radial head fracture. Various variables were examined. Results Of the 80 patients included, the mean age with standard deviation was 36.9 ± 8.8 years, and all patients were males. Nearly all patients with elbow dislocation had some form of posterior dislocation, including posterolateral (81.3%), posterior (10%), and posteromedial (7.5%) dislocation. The radial head fracture was identified in 48 (60%) cases. Radiographs were sufficient to diagnose 91.3% of radial head fractures, while the remaining 8.8% required additional CT. Conclusions Based on X-ray or CT findings, radial head fractures were found in more than half of traumatic elbow dislocations. In addition, most cases were diagnosed as an elbow dislocation and radial head fracture using only plain radiography, while some required additional CT. Based on these findings, we recommend routine CT to detect suspected elbow dislocation and avoid missing subtle injuries.

Predictive influence of artificial intelligence‐based body composition analysis in trauma patients with pelvic injuries

AbstractBackgroundHigh‐energy trauma patients represent the ultimate challenge to trauma care and are at risk of injury‐related mortality and morbidity—a common cause of loss of productivity. The aim of this study was to implement computed tomography (CT)‐derived, artificial intelligence (AI)‐based body composition analysis (BCA) to identify predictors of morbidity.MethodsRetrospectively, we enrolled 104 patients (38 females and 66 males) who underwent CT imaging for assessment of injuries caused by high‐energy trauma (motor vehicle accidents, falls from significant height, or blast injury). We sought to identify risk factors for prolonged length of stay in hospital and intensive care unit (ICU) and fractures requiring pelvic surgery. Cox and logistic regression analysis were performed using BCA parameters as covariates besides conventional risk factors. Additionally, the effects of pre‐existing conditions, obesity, and sarcopenia were analysed.ResultsIncreased subcutaneous adipose tissue (SAT), determined by BCA, at hospital admittance is a predictor of prolonged hospital stay (P = 0.02) independent of treatment regime and occurrence of related complications, whereas muscle mass does not influence the length of stay. Individuals with sarcopenia and a decreased psoas muscle index (PMI) sustaining high‐energy trauma are at risk of pelvic injuries requiring surgical treatment.ConclusionBCA parameters are easily available from routine CT and significantly predict outcomes in trauma patients with pelvic injuries. Patients with reduced muscle mass are at risk for injuries requiring pelvic surgery, and increased SAT is a risk factor for longer hospital stays. These findings underline the potential of BCA, which may be valuable in identifying trauma patients who require specific support to optimize their physiological reserves and clinical outcome.

Quantitative imaging predicts pancreatic fatty infiltration on routine CT examination

PurposeThe purpose of this study was to assess the performance of quantitative computed tomography (CT) imaging for detecting pancreatic fatty infiltration, using the results of histopathological analysis as reference. Materials and methodsSixty patients who underwent pancreatic surgery for a pancreatic tumor between 2016 and 2019 were retrospectively included. There were 33 women and 27 men with a mean age of 56 ± 12 (SD) years (age range: 18–79 years). Patients with dilatation of the main pancreatic duct, chronic pancreatitis, or preoperative treatment were excluded to prevent any bias in the radiological-pathological correlation. Pancreatic fatty infiltration was recorded at pathology. Pancreatic surface lobularity, pancreatic attenuation, visceral fat area, and subcutaneous fat area were derived from preoperative CT images. The performance for the prediction of fatty infiltration was assessed using area under receiver operating characteristic curve (AUC) and backward binary logistic regression analysis. Results were validated in a separate cohort of 34 patients (17 women; mean age, 50 ± 14 [SD] years; age range: 18–73). ResultsA total of 28/60 (47%) and 17/34 (50%) patients had pancreatic fatty infiltration in the derivation and validation cohorts, respectively. In the derivation cohort, patients with pancreatic fatty infiltration had a significantly higher PSL (P < 0.001) and a lower pancreatic attenuation on both precontrast and portal venous phase images (P = 0.011 and 0.003, respectively), and higher subcutaneous fat area and visceral fat area (P = 0.010 and 0.007, respectively). Multivariable analysis identified pancreatic surface lobularity > 7.6 and pancreatic attenuation on portal venous phase images < 83.5 Hounsfield units as independently associated with fatty infiltration. The combination of these variables resulted in an AUC of 0.85 (95% CI: 0.74–0.95) and 0.83 (95% CI: 0.67–0.99) in the derivation and validation cohorts, respectively. ConclusionCT-based quantitative imaging accurately predicts pancreatic fatty infiltration.

Height Estimation from Vertebral Parameters on Routine Computed Tomography in a Contemporary Elderly Australian Population: A Validation of Existing Regression Models.

The aim of this study is to compare previously published height estimation formulae in a contemporary Australian population using vertebral measurements readily available on abdominal CT. Retrospective analysis of patients undergoing a planning CT prior to transcatheter aortic valve implantation in a 12-month period was conducted; 96 participants were included in the analysis from a total of 137, with 41 excluded due to incomplete data. Seven vertebral measurements were taken from the CT images and height estimates were made for each participant using multiple regression equations from the published literature. Paired sample t-tests were used to compare actual height to estimated height. Many of the models failed to accurately predict patient height in this cohort, with only three equations for each sex resulting in a predicted height that was not statistically significantly different to actual height. The most accurate model in female participants was based on posterior sacral length and resulted in a mean difference between an actual and calculated height of 0.7 cm (±7.4) (p = 0.520). The most accurate model in male participants was based on anterior sacrococcygeal length and resulted in a mean difference of -0.6 ± 6.9 cm (p = 0.544). Height estimation formulae can be used to predict patient height from common vertebral parameters on readily available CT data. This is important for the calculation of anthropometric measures for a variety of uses in clinical medicine. However, more work is needed to generate accurate prediction models for specific populations.

Fracture Risk in Men and Women With Vertebral Fractures Identified Opportunistically on Routine Computed Tomography Scans and Not Treated for Osteoporosis: An Observational Cohort Study.

Vertebral fractures (VFs) have been associated with future fractures, yet few studies have evaluated whether this pertains to VFs available for identification on routine radiological imaging. We sought to evaluate the risk of subsequent fractures in subjects with VF identified opportunistically on computed tomography (CT) scans performed as part of routine clinical practice. From the radiology database of Holbæk Hospital we identified the first CT scan including the thorax and/or abdomen of 2000 consecutive men and women aged 50 years or older, performed from January 1, 2010 onward. The scans were assessed in a blinded approach to identify chest and lumbar VF, and these data linked to national Danish registers. Subjects were excluded if treated with an osteoporosis medication (OM) in the year prior to baseline (date of CT), and the remaining subjects with VF matched on age and sex in 1:2 ratio against subjects with no VF. We found that the risk of major osteoporotic fractures (hip, non-cervical vertebral, humerus, and distal forearm fractures) was higher for subjects with VF than without VF: incidence rates (IRs) were 32.88 and 19.59 fractures per 1000 subject-years, respectively, and the adjusted hazard ratio (HRadj) was 1.72 (95% confidence interval [CI], 1.03-2.86). Subsequent hip fracture IRs were 16.75 and 6.60; HRadj 3.02 (95% CI, 1.39-6.55). There were no significant differences in other fracture outcomes (including a pooled estimate of any subsequent fracture, except face, skull, and fingers: IRs 41.52 and 31.38; HRadj 1.31 [95% CI, 0.85-2.03]). Our findings suggest that subjects undergoing routine CT scans including the chest and/or abdomen are a high risk population in terms of fracture risk. Even within this group, subjects with VF are at higher risk of future major osteoporotic fracture (MOF), in particular hip fracture. Hence, systematic opportunistic screening for VF and subsequent fracture risk management is important to reduce the risk of new fractures. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Association Between the Bone Density of Posterior Fusion Mass and Mechanical Complications After Thoracolumbar Three-Column Osteotomy for Adult Spinal Deformity.

Retrospective comparative study. To assess the relationship of fusion mass bone density on computed tomography (CT) and the development of rod fractures (RFs) and proximal junctional kyphosis (PJK). Few studies have evaluated the relationship of fusion mass bone density to mechanical complications. A retrospective review of adult spinal deformity patients who underwent thoracolumbar three-column osteotomy from 2007 to 2017 was performed. All patients underwent routine 1-year CT imaging and had at least 24 months follow-up. Posterior fusion mass bone density was evaluated by measuring hounsfield unit (HU) on CT in three different regions [upper instrumented vertebra (UIV), lower instrumented vertebra, and osteotomy site], and were compared between patients with and without mechanical complications. A total of 165 patients (63.2 years, 33.5% male) were included. Overall PJK rate was 18.8%, and 35.5% of these underwent PJK revision. There was significantly lower density of posterior fusion mass at the UIV in patients who experienced PJK compared with patients without PJK (431.5HU vs. 537.4HU, P =0.026). Overall RF rate was 34.5% and 61.4% of these underwent revision for RFs. Among 57 patients with RFs, 71.9% had pseudarthrosis. Fusion mass density did not differ between patients with or without RFs. However, in RF patients with pseudarthrosis, there was significantly higher bone mass density near the osteotomy compared with those without pseudarthrosis (515.7HU vs. 354.2HU, P =0.012). There were no differences in radiographic sagittal measures between the patients with and without RF or PJK. Patients with PJK tend to have less dense posterior fusion mass at the UIV. Fusion mass density does not correlate with RF, but greater bone density near the osteotomy was correlated with accompanying pseudarthrosis in patients with RFs. Assessing density of posterior fusion mass on CT may be helpful in assessing risk for PJK and provide insight as to the causes of RFs.

Usefulness of cardiac computed tomography in prosthetic heart valve dysfunction

BackgroundProsthetic heart valve (PHV) dysfunction is a serious complication. Echocardiography remains the first-line imaging investigation to assess PHV dysfunction. However, the role of Computed Tomography (CT) scanning in this type of case has not been thoroughly studied yet.The objective of our study was to determine if cardiac Computed Tomography (CT) had a potentially complementary role to play alongside echocardiography in diagnosing the mechanism of prosthetic valve dysfunction. Methods and resultsThis prospective cohort study was conducted on 54 patients with suspected PHV dysfunction. All patients underwent routine diagnosis work-up (transthoracic and transesophageal echocardiography) and additional cardiac CT. Cardiac CT showed findings that were not detected by echocardiography in seven patients (12%) namely aortic pannus (5) and pseudoaneurysm (2). An underlying thrombus was detected by echocardiography and missed by cardiac CT in 15 patients (27%). However, in these thrombotic cases, cardiac CT contributed to the functional evaluation of leaflets. ConclusionThis study demonstrates that an integrated approach including transthoracic, transesophageal echocardiography and computed tomography is useful in patients with suspected PHV dysfunction. While computed tomography is more accurate in the diagnosis of pannus formation and periannular complications, echocardiography is superior at detecting thrombus.

Image findings of tendon sheaths affected by diffuse tenosynovial giant cell tumors of the skull base.

This study investigated radiographic images and the differential diagnosis of intracranial diffuse tenosynovial giant cell tumor (D-TGCT) in order to better understand the disease and improve the rate of preoperative diagnosis. Images and clinical data of patients with D-TGCT were retrospectively analyzed. Routine Computer Tomography (CT), routine Magnetic Resonance Imaging (MRI), and contrast-enhanced MRI were performed for nine cases. Susceptibility-weighted imaging (SWI) was also performed for one case. We reviewed nine patients (6 males and 3 females) aged between 24 and 64 years, with a mean age of 47.33 ± 14.92 years. The most frequent complaints were hearing loss (5/9, 55.6%), pain (4/9, 44%), masticatory symptoms (2/9, 22.2%), and mass (4/9, 44.4%), with a mean duration of 22 ± 21.43 months. All cases were centered on the base of the skull, and showed hyper-density soft-tissue mass with osteolytic bone destruction on CT. The tumor signal mainly showed iso-intensity or hypo-intensity on T1WI compared with that in the brain parenchyma in all patients. On T2WI, nine lesions mainly showed hypo-intensity. Among these nine lesions, three displayed cystic region showing hyper-intensity on T2WI and hypo-intensity on T1WI (Figure 2A, 2B) in the lesion. Nine lesions showed hypo-intensity on DWI sequences. SWI images presented low signal in two cases, showing the "flowering effect". Nine patients showed heterogeneous enhancement, and two patients had meningeal thickening. Intracranial D-TGCT is extremely rare, but must be differentiated from other tumors. Osteolytic bone destruction in the area of the skull base with hyper-density soft-tissue mass and hypo-intensity on T2WI images are indicative of D-TGCT.

Computed tomography derived cervical fat-free muscle fraction as an imaging-based outcome marker in patients with acute ischemic stroke: a pilot study

BackgroundOutcome assessment in stroke patients is essential for evidence-based stroke care planning. Computed tomography (CT) is the mainstay of diagnosis in acute stroke. This study aimed to investigate whether CT-derived cervical fat-free muscle fraction (FFMF) as a biomarker of muscle quality is associated with outcome parameters after acute ischemic stroke.MethodsIn this retrospective study, 66 patients (mean age: 76 ± 13 years, 30 female) with acute ischemic stroke in the anterior circulation who underwent CT, including CT-angiography, and endovascular mechanical thrombectomy of the middle cerebral artery between August 2016 and January 2020 were identified. Based on densitometric thresholds, cervical paraspinal muscles covered on CT-angiography were separated into areas of fatty and lean muscle and FFMF was calculated. The study cohort was binarized based on median FFMF (cutoff value: < 71.6%) to compare clinical variables and outcome data between two groups. Unpaired t test and Mann-Whitney U test were used for statistical analysis.ResultsNational Institute of Health Stroke Scale (NIHSS) (12.2 ± 4.4 vs. 13.6 ± 4.5, P = 0.297) and modified Rankin scale (mRS) (4.3 ± 0.9 vs. 4.4 ± 0.9, P = 0.475) at admission, and pre-stroke mRS (1 ± 1.3 vs. 0.9 ± 1.4, P = 0.489) were similar between groups with high and low FFMF. NIHSS and mRS at discharge were significantly better in patients with high FFMF compared to patients with low FFMF (NIHSS: 4.5 ± 4.4 vs. 9.5 ± 6.7; P = 0.004 and mRS: 2.9 ± 2.1 vs.3.9 ± 1.8; P = 0.049). 90-day mRS was significantly better in patients with high FFMF compared to patients with low FFMF (3.3 ± 2.2 vs. 4.3 ± 1.9, P = 0.045).ConclusionCervical FFMF obtained from routine clinical CT might be a new imaging-based muscle quality biomarker for outcome prediction in stroke patients.

Routine postoperative computed tomography (CT) scans following acetabulum open reduction internal fixation (ORIF): A survey of orthopaedic traumatologists

ObjectiveThe purpose of this study was to assess the practices related to obtaining postoperative pelvic CT scans following acetabular ORIF and revision surgery rates. DesignA 20-question survey published on the Orthopaedic Trauma Association (OTA) website assessed each surgeon's preference and rationale for or against the routine use of postoperative CT scans for acetabular fractures. ParticipantsFellowship-trained orthopaedic traumatologists. Main outcome measurementsWe examined the percentage of surgeons ordering routine postoperative CT scans, surgeon demographics, and revision surgery rates based on these routine CT scan results. ResultsResponses were received from 57 surgeons. Practices varied regarding postoperative CT scans, with 16 surgeons (28%, Group A) routinely ordering them and 41 surgeons (72%, Group B) not ordering them on all patients. No significant difference in surgeon demographics were found between the groups. Majority of Group A report a revision surgery rate of <1% based on the results of the postoperative CT.Group A report routine postoperative scans were obtained to assess reduction, hardware placement, identify intra-articular fragments, and for educational purposes. Group B did not obtain routine postoperative CTs due to the following: unlikely to change postoperative treatment, adequate reduction and instrumentation placement assessed intraoperatively and by postoperative radiographs, and increased radiation exposure and cost to patients. Group B did report obtaining postop CT scans on select patients, with inadequate intraoperative imaging and postoperative neurological changes being the most common indications. ConclusionThe routine use of postoperative CTs following open reduction internal fixation of acetabular fractures is a controversial topic. While we recognize the role for postoperative CT scans in select patients, our study questions the clinical utility of these scans in all patients and in conclusion do not recommend this protocol.

Ultra-low-dose CT lung screening with artificial intelligence iterative reconstruction: evaluation via automatic nodule-detection software

To test the feasibility of ultra-low-dose (ULD) computed tomography (CT) combined with an artificial intelligence iterative reconstruction (AIIR) algorithm for screening pulmonary nodules using computer-assisted diagnosis (CAD). A chest phantom with artificial pulmonary nodules was first scanned using the routine protocol and the ULD protocol (3.28 versus 0.18 mSv) to compare the image quality and to test the acceptability of the ULD CT protocol. Next, 147 lung-screening patients were enrolled prospectively, undergoing an additional ULD CT immediately after their routine CT examination for clinical validation. Images were reconstructed with filtered back-projection (FBP), hybrid iterative reconstruction (HIR), the AIIR, and were imported to the CAD software for preliminary nodule detection. Subjective image quality on the phantom was scored using a five-point scale and compared using the Mann-Whitney U-test. Nodule detection using CAD was evaluated for ULD HIR and AIIR images using the routine dose image as reference. Higher image quality was scored for AIIR than for FBP and HIR at ULD (p<0.001). As reported by CAD, 107 patients were presented with more than five nodules on routine dose images and were chosen to represent the challenging cases at an early stage of pulmonary disease. Among such, the performance of nodule detection by CAD on ULD HIR and AIIR images was 75.2% and 92.2% of the routine dose image, respectively. Combined with AIIR, it was feasible to use an ULD CT protocol with 95% dose reduction for CAD-based screening of pulmonary nodules.

OUTCOMES OF ISOLATED SIGMOID COLON THICKENING DETECTED ON ROUTINE COMPUTED TOMOGRAPHY EXAMINATIONS

Objective To determine outcomes of isolated sigmoid colon thickening detected on computed tomography (CT) and to evaluate certain clinical and CT findings that could help in diagnoses. Method This retrospective observational study was performed evaluating CT imaging data of all consecutive adult patients who presented with acute lower abdominal pains in emergency departments and were found to have isolated sigmoid colonic thickening on routine venous phase CT studies, between January 2020 to January 2022. Pre- viously operated cases, known inflammatory bowel disease patients, and those with known sigmoid malignancies were excluded. CT findings regarding the length of the sigmoid segment affected (less or more than 10 cm), mucosal pattern (symmet- ric or asymmetric), presence of diverticula, lymph nodes, and additional features (pericolic abscess or fistula formation, extra-luminal air foci or perforation, local invasion) were documented. Two experienced radiologists made consensus report- ing. Final diagnoses were confirmed on (endoscopic) biopsy results. Patients who did not have endoscopies or were medically treated were excluded. Age, gender, and CT findings were compared with outcomes, and any association was determined by the Chi-squared test. Results Out of 30 patients (aged between 20-75 years), the majority were males (n=21) and above 40 years (n=22). Twelve patients had colonic malignancies while 18 had benign findings. Acute presentation, younger patients, and those showing the presence of diver- ticula on CT scans were associated with benign biopsies. Conclusion Younger patients who present acutely and show diverticula on CT imaging may have benign causes of sigmoid thickening.

Incidental findings involving the temporomandibular joint on computed tomography and magnetic resonance imaging.

The temporomandibular joint (TMJ) is frequently imaged in head and neck computed tomography (CT) and magnetic resonance imaging (MRI) studies. Depending on the indication for the study, an abnormality of the TMJ may be an incidental finding. These findings encompass both intra- and extra-articular disorders. They may also be related to local, regional or systemic conditions. Familiarity with these findings along with pertinent clinical information helps narrow the list of differential diagnoses. While definitive diagnosis may not be immediately apparent, a systematic approach contributes to improved discussions between clinicians and radiologists and better patient management.

On the relationship between CT measured abdominal fat parameters and three metabolic risk biomarkers

Abstract Introduction: Cardiovascular diseases are the leading cause of morbidity and mortality worldwide, and there is a need for the development of adjacent markers to assess cardiovascular risk. In this study, we examined the relationship between the areas of abdominal fat compartments, as measured by computed tomography (CT)-based planar measurements, and laboratory-validated cardiovascular risk markers. Methods: Fat distribution was measured on CT scans in 252 patients (M: F = 1.13) who underwent routine abdominal CT, using in-house and commercially available software. The included laboratory parameters were glucose, triglycerides, and the triglycerideglucose index. Results: The visceral abdominal fat (VAF) area and VAF percentage were lower in females compared to the VAF area and VAF percentage in males, (p=0.001, and p&lt;0.001 respectively). However, the total abdominal fat (TAF) area was not significantly different between genders. Visceral fat and triglyceride levels showed a weakly positive connection for females (r=0.447, p=0.002) but not for males (r=0.229, p=0.09). The glucose levels had a weak correlation with CT calculated abdominal fat parameters, with the strongest statistically significant correlation value being with TAF for females (r=0.331, p=0.003). Conclusions: Areas of abdominal fat compartments correlate with metabolic parameters in the blood, and in the future, their assessment might be considered when constructing risk scores. Visceral fat content assessment for every abdominal computed tomography procedure might become a surrogate marker for cardio-vascular risk estimation after defining clear cut-off values and image analysis parameters.

Методика оценки радиационного риска медицинского облучения при прохождении компьютерной томографии с учётом неопределённостей модели риска

The paper presents analysis of different factors affecting the uncertainty model for estimating ra-diation risk from computed tomography (CT). Uncertainties in radiation doses estimates caused by measurement (instrumental) errors or used dose estimation methods, the size of the scanned area and the type of CT scanner. The uncertainty of radiation dose due to measurement errors or dose estimation methods, the size of the scanned area and type of a CT scan may cause the uncertainties as well. Data used for calculating equivalent doses in individual organs and tissues and for calculating lifetime radiation risk of cancer development due to routine CT testing were updated. Conversion factors for DLP, a measure of radiation dose a patient received during CT exams of thoracic, abdomen and head organs, were determined and used for conversion of the CT doses to equivalent doses for individual organs and tissues exposed to radiation. Data for 15 state-of-the-art CT scanners with varying scanning geometry were updated. Uncertainties in life-time radiation risk were determined by estimating 95% confidence intervals for mean dose-proportionality ratios. Standard deviations related to specific dose distribution, scanning geometry and other factors that impact on uncertainty of radiation risk estimates were calculated. The standard deviations associated with the specifics of the dose distribution, scanning geometry and other factors affecting the uncertainties of radiation risk assessments were calculated. In the course of simulation modelling, organs and tissues were identified that are most exposed to radiation during CT of the chest, abdomen and head.

Routine Computed Tomography Versus Selective Imaging: An Audit of Negative Appendicectomy Rates in Two Hospitals.

Introduction There are a variety of conflicting recommendations in the literature for pre-operative imaging in acute appendicitis. There is debate over what the ideal imaging protocol is to lower the negative appendicectomy rate (NAR) without increasing missed appendicitis. The aim of this study is to compare the audited NAR between two groups with different imaging approaches: (i) mandatory pre-operative computed tomography (CT) imaging and (ii) selective imaging with CT, ultrasound (US), or no imaging prior to appendicectomy. Materials and methods A retrospective chart audit was conducted of 400 patients who underwent an appendicectomy at two hospitals with different approaches to pre-operative imaging (hospital A and hospital B). The primary outcome measure was histologically confirmed appendicitis. It was also documented whether there was radiological (CT or US) evidence of appendicitis. Results At hospital A, all 200 patients underwent CT imaging prior to appendicectomy. The total histologically confirmed NAR for this group was 9.5% (19/200). At hospital B, 97 (48.5%) patients underwent CT, 41 (25.5%) underwent US, 10 (5%) had both US and CT, and 52 (26%) had no imaging. The total NAR was 11.5% (23/200). Conclusion There was no statistically significant difference (p=0.62) in audited NARs when comparing clinician-guided selective imaging versus routine CT imaging for all patients undergoing appendicectomy.

Clinical application of the contrast-enhancement boost technique in computed tomography angiography of the portal vein

PurposeThe aim of this study was to explore the improved image quality of the portal vein using the contrast-enhancement boost (CE-boost) technique for the improved visibility of abdominal-enhanced computed tomography (CT) scans in clinical practice.MethodsThis retrospective study included 50 patients in Group A who underwent routine abdominal-enhanced CT and 50 patients in Group B who underwent abdominal computed tomography angiography (CTA) with matched body mass index, age, and sex. Images in Group A were postprocessed with the CE-boost technique for further enhanced visibility of the portal vein. Both subjective and objective assessments of different branches of the portal vein in three types of images (i.e., Group A with CE-boost and without CE-boost, Group B) were statistically analyzed.ResultsThe subjective scores of two experienced radiologists showed good consistency (kappa value > 0.624, p < 0.001), and the score of Group A with CE-boost (mean, 4.64) was significantly higher than that of the others (p < 0.001). The liver parenchyma and most target veins in Group A with CE-boost showed the highest CT, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) values and the lowest standard deviation (SD), while the CNR of most portal veins in Group A without CE-boost had the lowest CNR (p < 0.001). There were no differences in the SNR of the portal vein in Group A without CE-Boost and Group B (p > 0.05).ConclusionCE-boost can significantly improve image quality in portal vein imaging without any additional scanning settings or changes in the clinical workflow.Graphical

Cardiovascular parameters on computed tomography are independently associated with in-hospital complications and outcomes in level-1 trauma patients

BackgroundIn-hospital complications after trauma may result in prolonged stays, higher costs, and adverse functional outcomes. Among reported risk factors for complications are pre-existing cardiopulmonary comorbidities. Objective and quick evaluation of cardiovascular risk would be beneficial for risk assessment in trauma patients. Studies in non-trauma patients suggested an independent association between cardiovascular abnormalities visible on routine computed tomography (CT) imaging and outcomes. However, whether this applies to trauma patients is unknown.PurposeTo assess the association between cardiopulmonary abnormalities visible on routine CT images and the development of in-hospital complications in patients in a level-1 trauma center.MethodsAll trauma patients aged 16 years or older with CT imaging of the abdomen, thorax, or spine and admitted to the UMC Utrecht in 2017 were included. Patients with an active infection upon admission or severe neurological trauma were excluded. Routine trauma CT images were analyzed for visible abnormalities: pulmonary emphysema, coronary artery calcifications, and abdominal aorta calcification severity. Drug-treated complications were scored. The discharge condition was measured on the Glasgow Outcome Scale.ResultsIn total, 433 patients (median age 50 years, 67% male, 89% ASA 1–2) were analyzed. Median Injury Severity Score and Glasgow Coma Scale score were 9 and 15, respectively. Seventy-six patients suffered from at least one complication, mostly pneumonia (n = 39, 9%) or delirium (n = 19, 4%). Left main coronary artery calcification was independently associated with the development of any complication (OR 3.9, 95% CI 1.7–8.9). An increasing number of calcified coronary arteries showed a trend toward an association with complications (p = 0.07) and was significantly associated with an adverse discharge condition (p = 0.02). Pulmonary emphysema and aortic calcifications were not associated with complications.ConclusionCoronary artery calcification, visible on routine CT imaging, is independently associated with in-hospital complications and an adverse discharge condition in level-1 trauma patients. The findings of this study may help to identify trauma patients quickly and objectively at risk for complications in an early stage without performing additional diagnostics or interventions.

Trainable joint bilateral filters for enhanced prediction stability in low-dose CT

Low-dose computed tomography (CT) denoising algorithms aim to enable reduced patient dose in routine CT acquisitions while maintaining high image quality. Recently, deep learning (DL)-based methods were introduced, outperforming conventional denoising algorithms on this task due to their high model capacity. However, for the transition of DL-based denoising to clinical practice, these data-driven approaches must generalize robustly beyond the seen training data. We, therefore, propose a hybrid denoising approach consisting of a set of trainable joint bilateral filters (JBFs) combined with a convolutional DL-based denoising network to predict the guidance image. Our proposed denoising pipeline combines the high model capacity enabled by DL-based feature extraction with the reliability of the conventional JBF. The pipeline’s ability to generalize is demonstrated by training on abdomen CT scans without metal implants and testing on abdomen scans with metal implants as well as on head CT data. When embedding RED-CNN/QAE, two well-established DL-based denoisers in our pipeline, the denoising performance is improved by 10%/82% (RMSE) and 3%/81% (PSNR) in regions containing metal and by 6%/78% (RMSE) and 2%/4% (PSNR) on head CT data, compared to the respective vanilla model. Concluding, the proposed trainable JBFs limit the error bound of deep neural networks to facilitate the applicability of DL-based denoisers in low-dose CT pipelines.