CT Scans and Cancer Risks: A Systematic Review and Dose-response Meta-analysis

Gender differences in the diagnostic efficacy of coronary CTA: Overutilization of coronary CTA in pre- and perimenopausal females?

OBJECTIVES

Public campaigns such as the "Go-red-for-women"-initiative have raised heart-disease awareness and may trigger overutilization of coronary computed tomography angiography (CTA). Objective was to investigate the diagnostic efficacy of coronary CTA stratified by age and gender.

METHODS

1882 consecutive patients (58.9 ± 11 years;42.5% females) with low-to-intermediate pre-test-probability of coronary artery disease (CAD) referred to coronary CTA according to ESC-2019 guidelines, were included. Diagnostic efficacy was defined by the 1)negative CTA-rate 2)obstructive CAD (>50%stenosis) 3)High-risk-plaque and 4)CAC-score.

RESULTS

The negative CTA rate was higher in females compared to males with 360/801 vs 292/1081 (45% vs 27%;p < 0.001). Females had a higher likelihood (OR 2.2:95%CI:1.81-2.67) of a negative CTA than males, despite they were older (p < 0.001). Obstructive disease prevalence was 25.6% and acceptable in both sexes (males vs females: 28.4% vs 21.8%;p = 0.0012). Males had more high-risk-plaque (23.6% vs 11.5%;p < 0.001). When stratifying age groups, negative CTA rate was highest in females <47 years (82.8%), but lower in males with 68.1% (p < 0.001), while obstructive disease prevalence was not different (males:6.5% vs females:4.6%:p = 0.874). Above 50 years, negative CTA rate (39.1% vs 17.6%,p < 0.001;OR 3.02:95%CI:2.381-3.823) was higher, and the obstructive disease rate was lower in females (24.8% vs 34.7%,p = 0.0003). SSPSTm(V.25,IBM) was used for statistical analysis.

CONCLUSIONS

Above 50 years of age, diagnostic efficacy of coronary CTA is high in both males and females. In females <47 years, the negative CTA rate was highest with 82.8% and obstructive disease prevalence was low (4.6%), still justifying testing but recommending the use of specific tools (PROMISE minimal risk score) or other clinical tests for pre-selection.

Overutilization of head computed tomography in cases of mild traumatic brain injury: a systematic review and meta-analysis

Head computed tomography (CT) is the preferred imaging modality for mild traumatic brain injury (mTBI). The routine use of head CT in low-risk individuals with mild TBI offers no clinical benefit but also causes notable health and financial burden. Despite the availability of related guidelines, studies have reported considerable rate of non-indicated head CT requests. The objectives were to provide an overall estimate for the head CT overutilization rate and to identify the factors contributing to the overuse. A systematic review of PubMed, Scopus, Web of Science, and Embase databases was conducted up to November 2023, following PRISMA and MOOSE guidelines. Two reviewers independently selected eligible articles and extracted data. Quality assessment was performed using a bias risk tool, and a random-effects model was used for data synthesis. Fourteen studies, encompassing 28,612 patients, were included, with 27,809 undergoing head CT scans. Notably, 75% of the included studies exhibited a moderate to high risk of bias. The overutilization rate for pediatric and adult patients was 27% (95% CI: 5-50%) and 32% (95% CI: 21-44%), respectively. An alternative rate, focusing on low-risk pediatric patients, was 54% (95% CI: 20-89%). Overutilization rates showed no significant difference between teaching and non-teaching hospitals. Patients with mTBI from falls or assaults were less likely to receive non-indicated scans. There was no significant association between physician specialty or seniority and overuse, nor between patients' age or sex and the likelihood of receiving a non-indicated scan. Approximately one-third of head CT scans in mTBI cases are avoidable, underscoring the necessity for quality improvement programs to reduce unnecessary imaging and its associated burdens.

Clinical feasibility of deep learning based synthetic contrast enhanced abdominal CT in patients undergoing non enhanced CT scans

Our objective was to develop and evaluate the clinical feasibility of deep-learning-based synthetic contrast-enhanced computed tomography (DL-SynCCT) in patients designated for nonenhanced CT (NECT). We proposed a weakly supervised learning with the utilization of virtual non-contrast CT (VNC) for the development of DL-SynCCT. Training and internal validations were performed with 2202 pairs of retrospectively collected contrast-enhanced CT (CECT) images with the corresponding VNC images acquired from dual-energy CT. Clinical validation was performed using an external validation set including 398 patients designated for true nonenhanced CT (NECT), from multiple vendors at three institutes. Detection of lesions was performed by three radiologists with only NECT in the first session and an additionally provided DL-SynCCT in the second session. The mean peak signal-to-noise ratio (PSNR) and structural similarity index map (SSIM) of the DL-SynCCT compared to CECT were 43.25 ± 0.41 and 0.92 ± 0.01, respectively. With DL-SynCCT, the pooled sensitivity for lesion detection (72.0% to 76.4%, P < 0.001) and level of diagnostic confidence (3.0 to 3.6, P < 0.001) significantly increased. In conclusion, DL-SynCCT generated by weakly supervised learning showed significant benefit in terms of sensitivity in detecting abnormal findings when added to NECT in patients designated for nonenhanced CT scans.

Evaluation of positioning accuracy, radiation dose and image quality: artificial intelligence based automatic versus manual positioning for CT KUB

Background

Recent innovations are making radiology more advanced for patient and patient services. Under the immense burden of radiology practice, Artificial Intelligence (AI) assists in obtaining Computed Tomography (CT) images with less scan time, proper patient placement, low radiation dose (RD), and improved image quality (IQ). Hence, the aim of this study was to evaluate and compare the positioning accuracy, RD, and IQ of AI-based automatic and manual positioning techniques for CT kidney ureters and bladder (CT KUB).

Methods

This prospective study included 143 patients in each group who were referred for computed tomography (CT) KUB examination. Group 1 patients underwent manual positioning (MP), and group 2 patients underwent AI-based automatic positioning (AP) for CT KUB examination. The scanning protocol was kept constant for both the groups. The off-center distance, RD, and quantitative and qualitative IQ of each group were evaluated and compared.

Results

The AP group (9.66±6.361 mm) had significantly less patient off-center distance than the MP group (15.12±9.55 mm). There was a significant reduction in RD in the AP group compared with that in the MP group. The quantitative image noise (IN) was lower, with a higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the AP group than in the MP group (p<0.05). Qualitative IQ parameters such as IN, sharpness, and overall IQ also showed significant differences (p< 0.05), with higher scores in the AP group than in the MP group.

Conclusions

The AI-based AP showed higher positioning accuracy with less off-center distance (44%), which resulted in 12% reduction in RD and improved IQ for CT KUB imaging compared with MP.

Sound the Alarm: The Sonographer Shortage Is Echoing Across Healthcare

OBJECTIVES

The growth in ultrasound usage necessitates concurrent growth in the number of sonographers. Despite the increasing importance of ultrasound, there is a shortage of sonographers in the United States that has never been specifically quantified. This study examines recent trends in the number of ultrasound exams, sonography graduates, open sonographer positions, and wages.

METHODS

This retrospective study uses public databases and surveys including the Medical Expenditure Panel Survey (MEPS), Bureau of Labor Statistics (BLS), Integrated Postsecondary Education Data System (IPEDS), and Zippia, a human resources platform to determine metrics. These metrics include the number of ultrasound exams conducted in the United States (excluding inpatient setting), number of sonographers and sonographer wages, sonography graduates, and open sonographer positions.

RESULTS

Ultrasound exams in the United States from 2011 to 2021 increased from 38.6 million to 59.8 million (+55.1%,) while the number of sonographers (2011-2021) increased from 54,760 to 78,640 (+43.6%). There was a significant difference between supply and demand of sonographers with the number of sonography graduates (2011-2021) increasing from 4,386 to 5,393 (+23.0%) while the number of open sonographer positions (2012-2021) increased from 18,462 to 25,162 (+36.3%).

CONCLUSIONS

From 2011 to 2021, the increase in the number of ultrasound exams has significantly outpaced the increase in the number of sonographers. Furthermore, the increase in demand for sonographers has grown significantly faster than the supply, leading to a shortage and consequent strain on the healthcare system. To address the shortage, the number of sonography school openings should be increased, and the attendant challenges addressed.

Cumulative Dose from Recurrent CT Scans: Exploring the DNA Damage Response in Human Non-Transformed Cells

Recurrent computed tomography (CT) examination has become a common diagnostic procedure for several diseases and injuries. Though each singular CT scan exposes individuals at low doses of low linear energy transfer (LET) radiation, the cumulative dose received from recurrent CT scans poses an increasing concern for potential health risks. Here, we evaluated the biological effects of recurrent CT scans on the DNA damage response (DDR) in human fibroblasts and retinal pigment epithelial cells maintained in culture for five months and subjected to four CT scans, one every four weeks. DDR kinetics and eventual accumulation of persistent-radiation-induced foci (P-RIF) were assessed by combined immunofluorescence for γH2AX and 53BP1, i.e., γH2AX/53BP1 foci. We found that CT scan repetitions significantly increased both the number and size of γH2AX/53BP1 foci. In particular, after the third CT scan, we observed the appearance of giant foci that might result from the overlapping of individual small foci and that do not associate with irreversible growth arrest, as shown by DNA replication in the foci-carrying cells. Whether these giant foci represent coalescence of unrepaired DNA damage as reported following single exposition to high doses of high LET radiation is still unclear. However, morphologically, these giant foci resemble the recently described compartmentalization of damaged DNA that should facilitate the repair of DNA double-strand breaks but also increase the risk of chromosomal translocations. Overall, these results indicate that for a correct evaluation of the damage following recurrent CT examinations, it is necessary to consider the size and composition of the foci in addition to their number.

CT Angiography-Guided Needle Insertion for Interstitial Brachytherapy in Locally Advanced Cervical Cancer

CT angiography might be a suitable procedure to avoid arterial puncture in combined intracavitary and interstitial brachytherapy for cervical cancer curatively treated with combined chemoradiation and brachytherapy boost. Data in the literature about this technique are scarce. We introduced this method and collected brachytherapy data from patients treated in our department between May 2021 and April 2024. We analyzed the applicator subtype, needle insertion (planned versus implanted), implanted depth and the role of CT angiography in selecting needle trajectories and insertion depths. None of the patients managed through this protocol experienced atrial puncture and consequent hemorrhage. Needle positions were accurately selected with the aid of CT angiography with proper coverage of brachytherapy targets and avoidance of organs at risk. CT angiography is a promising method for guiding needle insertion during interstitial brachytherapy.

A Review of Recent Low-dose Research and Recommendations for Moving Forward

ABSTRACT

The linear no-threshold (LNT) model has been the regulatory "law of the land" for decades. Despite the long-standing use of LNT, there is significant ongoing scientific disagreement on the applicability of LNT to low-dose radiation risk. A review of the low-dose risk literature of the last 10 y does not provide a clear answer, but rather the body of literature seems to be split between LNT, non-linear risk functions (e.g., supra- or sub-linear), and hormetic models. Furthermore, recent studies have started to explore whether radiation can play a role in the development of several non-cancer effects, such as heart disease, Parkinson's disease, and diabetes, the mechanisms of which are still being explored. Based on this review, there is insufficient evidence to replace LNT as the regulatory model despite the fact that it contributes to public radiophobia, unpreparedness in radiation emergency response, and extreme cleanup costs both following radiological or nuclear incidents and for routine decommissioning of nuclear power plants. Rather, additional research is needed to further understand the implications of low doses of radiation. The authors present an approach to meaningfully contribute to the science of low-dose research that incorporates machine learning and Edisonian approaches to data analysis.

Patient perspectives on ionising radiation exposure from computed tomography in Saudi Arabia: a knowledge and perception study

The objective of this study was to evaluate patient knowledge and understanding of ionising radiation and dosage, as well as the accompanying risks related to computed tomography scans. A total of 412 outpatients who underwent computed tomography (CT) scans were surveyed to assess their understanding of radiation dose and exposure risks. CT was correctly classified as an ionising radiation by 56.8% of the respondents. More than half of the patients reported that a CT scan increases the probability of inducing cancer. Awareness of varying radiation doses in different CT exams was noted in 75.2% of patients, but only 21.4% reported having discussions with their physician about radiation dose. Gender, age and employment were significantly correlated with knowledge levels. The survey findings indicate a limited understanding of the hazards associated with ionising radiation used in CT scans, highlighting a need for increased awareness and education on radiation protection to ensure informed consent.

Influence of deep learning image reconstruction algorithm for reducing radiation dose and image noise compared to iterative reconstruction and filtered back projection for head and chest computed tomography examinations: a systematic review

Background

The most recent advances in Computed Tomography (CT) image reconstruction technology are Deep learning image reconstruction (DLIR) algorithms. Due to drawbacks in Iterative reconstruction (IR) techniques such as negative image texture and nonlinear spatial resolutions, DLIRs are gradually replacing them. However, the potential use of DLIR in Head and Chest CT has to be examined further. Hence, the purpose of the study is to review the influence of DLIR on Radiation dose (RD), Image noise (IN), and outcomes of the studies compared with IR and FBP in Head and Chest CT examinations.

Methods

We performed a detailed search in PubMed, Scopus, Web of Science, Cochrane Library, and Embase to find the articles reported using DLIR for Head and Chest CT examinations between 2017 to 2023. Data were retrieved from the short-listed studies using Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines.

Results

Out of 196 articles searched, 15 articles were included. A total of 1292 sample size was included. 14 articles were rated as high and 1 article as moderate quality. All studies compared DLIR to IR techniques. 5 studies compared DLIR with IR and FBP. The review showed that DLIR improved IQ, and reduced RD and IN for CT Head and Chest examinations.

Conclusions

DLIR algorithm have demonstrated a noted enhancement in IQ with reduced IN for CT Head and Chest examinations at lower dose compared with IR and FBP. DLIR showed potential for enhancing patient care by reducing radiation risks and increasing diagnostic accuracy.

Clinical Application of Exercise Stress Echocardiography in an Outpatient Pediatric Population

Background: Exercise stress echocardiography (ESE) is commonly employed in adults, but its applicability in pediatric populations remains to be clarified. Methods: A total of 309 consecutive children (C), with a mean age of 14.1 ± 2.6 years (range 6-17 years), underwent treadmill ESE starting in 2002. They were divided into two groups: Group I comprised 258 children, including 237 with symptoms related to exercise (such as chest pain, fatigue, lipothymia/syncope, or one aborted sudden death), 15 with electrocardiogram (ECG) abnormalities, and 6 with a positive ECG stress test showing ST changes. Group II consisted of 10 asymptomatic children whose parents requested routine screening, 11 with symptoms unrelated to exercise, 12 with a family history of sudden death, and 17 with known pathologies (including 10 with hypertrophic cardiomyopathy, 2 with aortic coarctation, and the remainder with various conditions, such as Cortriatriatum sinister, pulmonary stenosis, subaortic stenosis, bicuspid aortic valve, left ventricular hypertrophy related to arterial hypertension, and aortic switch operation). Regional wall motion abnormalities (RWMAs) and transvalvular or intraventricular (IVG) gradients were assessed using 2D and continuous-wave Doppler, respectively, in all cases. Results: The success rate was 100% (309/309). Stress-induced RWMAs were observed in two children. A significant IVG (>30 mmHg) was detected in 101 out of the 258 children (39%) in Group I, who presented with exercise-related symptoms, ECG abnormalities, or positive stress ECG. In Group I, the odds ratio (OR) of ESE reproducing the symptoms in children with IVG compared to those without IVG was 8.22 (95% CI: 4.84-13.99, p < 0.001). Conclusions: Treadmill ESE is both feasible and safe for pediatric populations. RWMAs demonstrated limited utility in our cohort of children, while IVG induced by exercise was frequently observed in symptomatic children.

COVID-19 and cancer risk arising from ionizing radiation exposure through CT scans: a cross-sectional study

BACKGROUND

The surge in the utilization of CT scans for COVID-19 diagnosis and monitoring during the pandemic is undeniable. This increase has brought to the forefront concerns about the potential long-term health consequences, especially radiation-induced cancer risk. This study aimed to quantify the potential cancer risk associated with CT scans performed for COVID-19 detection.

METHODS

In this cross-sectional study data from a total of 561 patients, who were referred to the radiology center at Imam Hossein Hospital in Shahroud, was collected. CT scan reports were categorized into three groups based on the radiologist's interpretation. The BEIR VII model was employed to estimate the risk of radiation-induced cancer.

RESULTS

Among the 561 patients, 299 (53.3%) were males and the average age of the patients was 49.61 ± 18.73 years. Of the CT scans, 408 (72.7%) were reported as normal. The average age of patients with normal, abnormal, and potentially abnormal CT scans was 47.57 ± 19.06, 54.80 ± 16.70, and 58.14 ± 16.60 years, respectively (p-value < 0.001). The average effective dose was 1.89 ± 0.21 mSv, with 1.76 ± 0.11 mSv for males and 2.05 ± 0.29 mSv for females (p-value < 0.001). The average risk of lung cancer was 3.84 ± 1.19 and 9.73 ± 3.27 cases per 100,000 patients for males and females, respectively. The average LAR for all cancer types was 10.30 ± 6.03 cases per 100,000 patients.

CONCLUSIONS

This study highlights the critical issue of increased CT scan usage for COVID-19 diagnosis and the potential long-term consequences, especially the risk of cancer incidence. Healthcare policies should be prepared to address this potential rise in cancer incidence and the utilization of CT scans should be restricted to cases where laboratory tests are not readily available or when clinical symptoms are severe.

Circulating Cell-Free SHOX2 DNA Methylation Is a Predictive, Prognostic, and Monitoring Biomarker in Adjuvant and Palliative Anti-PD-1-Treated Melanoma

BACKGROUND

The majority of metastatic melanoma patients initially do not respond or acquire resistance to anti-programmed cell death 1 (PD-1) immunotherapy. Liquid biopsy biomarkers might provide useful early response information and allow for personalized treatment decisions.

METHODS

We prospectively assessed circulating cell-free SHOX2 DNA methylation (SHOX2 ccfDNAm) levels and their dynamic changes in blood plasma of melanoma patients by quantitative methylation-specific polymerase chain reaction. Patients were treated with either palliative (n = 42) or adjuvant (n = 55) anti-PD-1 immunotherapy. Moreover, we included n = 126 control patients without evidence of malignant disease. We analyzed SHOX2 ccfDNAm status prior to and 4 weeks after palliative treatment initiation with regard to outcome [objective response, progression-free survival (PFS), and overall survival (OS)]. In the adjuvant setting, we associated longitudinal SHOX2 ccfDNAm status with disease recurrence.

RESULTS

Sensitivity was 60% with 25/42 melanoma patients showing increased SHOX2 ccfDNAm levels, whereas specificity was 98% with 123/126 (P < 0.001) control patients having SHOX2 ccfDNAm levels below cut-off. Pretreatment SHOX2 ccfDNAm status did not correlate with outcome; however, SHOX2 ccfDNAm negativity 4 weeks after palliative treatment initiation was strongly associated with improved survival [PFS: hazard ratio (HR) = 0.25, P = 0.002; OS: HR = 0.12, P = 0.007]. Pretreatment positive patients who reached SHOX2 ccfDNAm clearance after 4 weeks of immunotherapy showed an exceptionally beneficial outcome. SHOX2 ccfDNAm testing allowed for an early detection of distant metastases in adjuvant-treated melanoma patients.

CONCLUSIONS

Our study suggests SHOX2 ccfDNAm to be an early predictor of outcome in anti-PD-1 treated melanoma patients. SHOX2 ccfDNAm testing may aid individualized treatment decision-making.

Breath biomarkers in Non-Carcinogenic diseases

The analysis of volatile organic compounds (VOCs) from human matrices like breath, perspiration, and urine has received increasing attention from academic and medical researchers worldwide. These biological-borne VOCs molecules have characteristics that can be directly related to physiologic and pathophysiologic metabolic processes. In this work, gathers a total of 292 analytes that have been identified as potential biomarkers for the diagnosis of various non-carcinogenic diseases. Herein we review the advances in VOCs with a focus on breath biomarkers and their potential role as minimally invasive tools to improve diagnosis prognosis and therapeutic monitoring.

Establishing Protocol-based Dose Metrics for Common Abdomen and Pelvis Computed Tomography Protocols

BACKGROUND AND AIM

The majority of the existing diagnostic reference levels (DRLs) that have been established for computed tomography (CT) are based on various anatomical locations, such as the head, chest, abdomen, etc. However, DRLs are initiated to improve radiation protection by conducting a comparison of similar examinations with similar objectives. The aim of this study was to explore the feasibility of establishing dose baselines based on common CT protocols for patients who underwent enhanced CT abdomen and pelvis exams.

METHODS

Dose length product total (tDLPs), volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), effective dose (E), and scan acquisition parameters for a total of 216 adult patients, who underwent an enhanced CT abdomen and pelvis exams over a one-year period, were obtained and retrospectively analyzed. Spearman coefficient and one-way ANOVA tests were used to check significant differences between dose metrics and the different CT protocols.

RESULTS

The data exhibited 9 different CT protocols to acquire an enhanced CT abdomen and pelvis exam at our institute. Out of these, 4 were found more common, i.e., CT protocols were acquired for a minimum of 10 cases. Triphasic liver demonstrated the highest mean and median tDLPs across all 4 CT protocols. Triphasic liver protocol registered the highest E followed by gastric sleeve protocol with a mean of 28.7 and 24.7 mSv, respectively. Significant differences (p < 0.0001) were found between the tDLPs of anatomical location and the CT protocol.

CONCLUSION

Evidently, wide variability exists across CT dose indices and patient dose metrics relying on anatomical-based dose baseline, i.e., DRLs. Patient dose optimizations require establishing dose baselines based on CT protocols rather than the anatomical location.

Patterns of computed tomography utilisation in injury management: latent classes approach using linked administrative data in Western Australia

PURPOSE

Whilst computed tomography (CT) imaging has been a vital component of injury management, its increasing use has raised concern regarding ionising radiation exposure. This study aims to identify latent classes (underlying patterns) of CT use over a 3-year period following the incidence of injury and factors predicting the observed patterns.

METHOD

A retrospective observational cohort study was conducted in 21,544 individuals aged 18 + years presenting to emergency departments (ED) of four tertiary public hospitals with new injury in Western Australia. Mixture modelling approach was used to identify latent classes of CT use over a 3-year period post injury.

RESULTS

Amongst injured people with at least one CT scan, three latent classes of CT use were identified including a: temporarily high CT use (46.4%); consistently high CT use (2.6%); and low CT use class (51.1%). Being 65 + years or older, having 3 + comorbidities, history with 3 + hospitalisations and history of CT use before injury were associated with consistently high use of CT. Injury to the head, neck, thorax or abdomen, being admitted to hospital after the injury and arriving to ED by ambulance were predictors for the temporarily high use class. Living in areas of higher socio-economic disadvantage was a unique factor associated with the low CT use class.

CONCLUSIONS

Instead of assuming a single pattern of CT use for all patients with injury, the advanced latent class modelling approach has provided more nuanced understanding of the underlying patterns of CT use that may be useful for developing targeted interventions.

Dose reduction does not impact the precision of CT-based RSA in tibial implants: a diagnostic accuracy study on precision in a porcine cadaver

BACKGROUND AND PURPOSE

Radiostereometric analysis (RSA) is the gold standard for evaluation of migration of implants. CT-RSA has been shown to have precision at the level of RSA in hip, shoulder, and knee joint replacements. We aimed to assess the impact of dose reduction on precision of CT-RSA on tibial implants, comparing it with previously published data on precision of standard dose CT-RSA on tibial implants.

MATERIAL AND METHODS

We performed a total knee arthroplasty on a porcine knee cadaver, and subsequent CT-RSA with low effective doses (0.02 mSv). We compared the results with previously published CT-RSA data with standard (0.08 mSv) dose. The primary outcome variable was the difference in precision of the maximum total translation (MTT). Secondary variables included ratios of variances and standard deviations, and precision of peripheral point translations, center-of-mass translations, and rotations. A difference of more than 0.1 mm in precision was defined as clinically relevant. Our hypothesis was that precisions of low and standard CT-RSA doses were equal.

RESULTS

Low dose (mean 0.07, 95% confidence interval [CI] 0.06-0.08) and standard dose CT-RSA (0.08, CI 0.07-0.09) achieve similar precision, with difference in precision of MTT of 0.01, CI 0.00-0.02 mm. The F-statistic (0.99, CI 0.63-1.55) and sdtest (1.05, CI 0.43-2.58) also supported this.

CONCLUSION

We conclude that the precision of low dose CT-RSA for tibial implants on a porcine cadaver is equal to standard dose CT-RSA. However, these findings should be confirmed in clinical trials.

Dose Optimization Using a Deep Learning Tool in Various CT Protocols for Urolithiasis: A Physical Human Phantom Study

Background and Objectives: We attempted to determine the optimal radiation dose to maintain image quality using a deep learning application in a physical human phantom. Materials and Methods: Three 5 × 5 × 5 mm3 uric acid stones were placed in a physical human phantom in various locations. Three tube voltages (120, 100, and 80 kV) and four current-time products (100, 70, 30, and 15 mAs) were implemented in 12 scans. Each scan was reconstructed with filtered back projection (FBP), statistical iterative reconstruction (IR, iDose), and knowledge-based iterative model reconstruction (IMR). By applying deep learning to each image, we took 12 more scans. Objective image assessments were calculated using the standard deviation of the Hounsfield unit (HU). Subjective image assessments were performed by one radiologist and one urologist. Two radiologists assessed the subjective assessment and found the stone under the absence of information. We used this data to calculate the diagnostic accuracy. Results: Objective image noise was decreased after applying a deep learning tool in all images of FBP, iDose, and IMR. There was no statistical difference between iDose and deep learning-applied FBP images (10.1 ± 11.9, 9.5 ± 18.5 HU, p = 0.583, respectively). At a 100 kV-30 mAs setting, deep learning-applied FBP obtained a similar objective noise in approximately one third of the radiation doses compared to FBP. In radiation doses with settings lower than 100 kV-30 mAs, the subject image assessment (image quality, confidence level, and noise) showed deteriorated scores. Diagnostic accuracy was increased when the deep learning setting was lower than 100 kV-30 mAs, except for at 80 kV-15 mAs. Conclusions: At the setting of 100 kV-30 mAs or higher, deep learning-applied FBP did not differ in image quality compared to IR. At the setting of 100 kV-30 mAs, the radiation dose can decrease by about one third while maintaining objective noise.

Computer-assisted Navigation in Lumbar Spine Instrumented Fusions: Comparison of In-hospital and 30-Day Postoperative Complications With Nonnavigated Fusions in a National Database

OBJECTIVE

To compare in-hospital and 30-day postoperative complications for lumbar spine operations with and without use of computer-assisted navigation.

METHODS

Patients who underwent 1-level to 3-level lumbar spinal instrumentation and fusions 2011 to 2014 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Emergent procedures and patients aged younger than 18 years were excluded. Patients whose surgery involved the use of computer-assisted navigation were propensity score matched 1:4 based on preoperative demographics and comorbidities to operations without the use of navigation. Multivariate analysis was done to compare postoperative complications.

RESULTS

In total, 8,500 patients (average age: 60.7 ± 12.9, male 3,866, female 4,634) were analyzed (1,700 navigation, 6,800 Non-Navigated). Operations with navigation had significantly fewer overall complications (24% vs. 27%, P = 0.008; odds ratio [OR] = 0.83; CI = 0.73 to 0.95), fewer minor complications (20% vs. 24%, P = 0.002; OR = 0.80; CI = 0.70 to 0.91), fewer blood transfusions (17% v. 20%, P = 0.013; OR = 0.82; CI = 0.71 to 0.95), more wound dehiscences (0.4% vs. 0.8%, P = 0.022; OR = 2.16; CI = 1.12,4.19), and shorter average lengths of hospital stays (4.8 ± 4.8 vs. 5.1 ± 5.8 days, P = 0.01). Operations with computer navigation had significantly longer average surgical times (247 ± 129 vs 221 ± 115 minutes, P < 0.001). No significant differences were observed in 30-day revision rates, readmissions, and mortality.

CONCLUSION

Although use of computer-assisted navigation in short-segment lumbar spine fusions (1 to 3 levels) did not decrease revision rates for screw misplacement within 30 days postoperatively, it independently reduced the frequency of blood transfusions and minor complications and decreased hospital lengths of stay compared with operations without navigation. These benefits came at the expense of increased surgical times and wound dehiscences within 30 days postoperatively. Given the inherent limitations of large national databases, these results warrant confirmation through prospective, multicenter investigations.

Coronary Computed Tomography vs. Cardiac Magnetic Resonance Imaging in the Evaluation of Coronary Artery Disease

Coronary artery disease (CAD) represents a widespread burden to both individual and public health, steadily rising across the globe. The current guidelines recommend non-invasive anatomical or functional testing prior to invasive procedures. Both coronary computed tomography angiography (cCTA) and stress cardiac magnetic resonance imaging (CMR) are appropriate imaging modalities, which are increasingly used in these patients. Both exhibit excellent safety profiles and high diagnostic accuracy. In the last decade, cCTA image quality has improved, radiation exposure has decreased and functional information such as CT-derived fractional flow reserve or perfusion can complement anatomic evaluation. CMR has become more robust and faster, and advances have been made in functional assessment and tissue characterization allowing for earlier and better risk stratification. This review compares both imaging modalities regarding their strengths and weaknesses in the assessment of CAD and aims to give physicians rationales to select the most appropriate modality for individual patients.