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Purpose of review Recent developments in low-dose computed tomography (ldCT) have greatly reduced radiation exposure levels. This article reviews what a ldCT is and its use and limitations for imaging axial spondyloarthritis. Rece...
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Purpose of review Recent developments in low-dose computed tomography (ldCT) have greatly reduced radiation exposure levels. This article reviews what a ldCT is and its use and limitations for imaging axial spondyloarthritis. Recent findings Detection of structural damage in bone with CT is far superior to radiography and ldCT of the sacroiliac joints (SIJ) can now be done at radiation exposure levels equivalent to, or even less than, conventional radiography. ldCT should be considered a ‘first-choice’ test for arthritis imaging, and wherever available, SIJ ldCT may completely replace conventional radiography. Radiation exposure in the spine with ldCT is lower than conventional CT. However, it is unclear whether the additional information regarding structural damage changes in the spine provided by ldCT will alter patient management sufficiently often to merit switching from spinal radiography to ldCT in routine clinical practice. In addition, ldCT cannot assess osteitis disease activity for which MRI remains the best test. Summary ldCT of the sacroiliac joints (SIJ) can be done at radiation exposure levels equivalent to, or less than, radiography and ldCT may completely replace SIJ radiography. However, the role of spinal ldCT for spondyloarthritis is not clear and MRI is far superior for detecting disease activity.
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Background Before introducing 70-kVp settings in the low-kilovoltage strategies for pediatric examinations, it was mandatory to demonstrate, at similar dose levels, an equivalence of image quality at 70 kVp and 80 kVp. Objective T...
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Background Before introducing 70-kVp settings in the low-kilovoltage strategies for pediatric examinations, it was mandatory to demonstrate, at similar dose levels, an equivalence of image quality at 70 kVp and 80 kVp. Objective To assess image quality of chest CT examinations acquired at 70 kVp in comparison with standard scanning at 80 kVp.Materials and methods We prospectively evaluated 129 children with a 70-kVp scanning protocol (group 1). All scanning parameters were kept similar to those usually selected for pediatric standard 80-kVp protocols, except the milliamperage increased by a factor of 1.6 to maintain comparable radiation dose. Image quality of group 1 examinations was compared to that of a paired population scanned at 80 kVp (group 2). The noninferiority hypothesis was fixed at 10% of the mean level of image noise. Results There was no significant difference in the mean dose length product (DLP) and the volume computed tomography dose index (CTDI_(vol)) between the groups (DLP: 20.5± 5.8 mGy.cm [group 1] vs. 19.7±7.6 mGy.cm [group 2];P=0.06) (CTDI_(vol): 0.8±0.1 mGy [group 1] vs. 0.8± 0.18 mGy [group 2]; P=0.94). The mean of differences in image noise between group 1 and group 2 examinations was -1.38 (-2.59; -0.18), verifying the noninferiority hypothesis. Subjective image quality did not significantly differ between group 1 and group 2 examinations (P=0.18).Conclusion At equivalent radiation dose levels, 70-kVp protocols provide similar image quality to that achievable at 80 kVp.
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Purpose: To analyze the quantitative and qualitative image quality of computed tomography (CT) of the extremities (shoulder, wrist, pelvis, and ankle joints) with low-dose radiation and standard-dose radiation.
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Background Hybrid SPECT/CT systems allow the shortening of lead time for investigation of cancer patients, since a complementary CT for radiological characterization of focally increased isotope uptake of unclear origin in bone sc...
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Background Hybrid SPECT/CT systems allow the shortening of lead time for investigation of cancer patients, since a complementary CT for radiological characterization of focally increased isotope uptake of unclear origin in bone scintigraphy can be performed simultaneously. The use of low-dose CT (sub-mSv CT) reduces radiation dose compared to standard-dose CT and facilitates the application of complementary CT. Purpose To test the feasibility of sub-mSv CT for the characterization of non-specific findings in the bone scintigraphy of oncological patients. Material and Methods Nineteen oncological patients with a total of 50 findings of unclear origin on bone scintigraphy which required further correlation with morphologic data were included in the study. Each patient underwent two CT scan series consecutively: one low-dose CT and one standard-dose CT. The CT studies were randomized and each finding was rated by four blinded experienced radiologists. A shift in ratings between standard-dose and low-dose images were assessed using the Stuart-Maxwell chi-squared test. Inter-observer agreement and intra-observer agreement was assessed using Light's kappa and Cohen's kappa, respectively. Results The mean effective dose of low-dose CT scans was 0.8 mSv compared to 4.2 mSv for the standard-dose CT scans. No statistically significant shift in ratings was observed (P = 0.62). There was no statistically significant difference in the inter-observer agreements: the values for the standard-dose and low-dose groups were 0.68 (95% confidence interval [CI] 0.57-0.79) and 0.60 (95% CI 0.47-0.72), respectively. Conclusion These results indicate that sub-mSv CT for characterization of non-specific findings in bone scintigraphy of oncological patients is feasible.
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Computed tomography (CT) is an indispensable tool for imaging of the thorax and there is virtually no alternative without associated radiation burden. The authors demonstrate ultra-low-dose CT of the thorax in three interesting ca...
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Computed tomography (CT) is an indispensable tool for imaging of the thorax and there is virtually no alternative without associated radiation burden. The authors demonstrate ultra-low-dose CT of the thorax in three interesting cases. In an 18-y-old girl with rheumatoid arthritis, CT of the thorax identified alveolitis in the posterior costophrenic angles (radiation dose = 0.2 mSv). Its resolution was demonstrated on a follow-up scan (4.2 mSv) performed elsewhere. In an 11-y-old girl, CT (0.1 mSv) showed changes of the right collar bone consistent with chronic recurrent multifocal osteomyelitis. CT (0.1 mSv) of a 9-y-old girl with mucopolysaccharidosis revealed altogether three hamartomas, peribronchial infiltrate, and spine deformity. In some indications, the radiation dose from CT of the thorax can approach that of several plain radiographs. This may help the pediatrician in deciding whether "gentle" ultra-low-dose CT instead of observation or follow-up radiographs will alleviate the uncertainty of the diagnosis with little harm to the child.
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Revolutionary developments in multidetector-row computed tomography (CT) scanner technology offer several advantages for imaging of cardiothoracic disorders. As a result, expanding applications of CT now account for >85 million CT...
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Revolutionary developments in multidetector-row computed tomography (CT) scanner technology offer several advantages for imaging of cardiothoracic disorders. As a result, expanding applications of CT now account for >85 million CT examinations annually in the United States alone. Given the large number of CT examinations performed, concerns over increase in population-based risk for radiation-induced carcinogenesis have made CT radiation dose a top safety concern in health care. In response to this concern, several technologies have been developed to reduce the dose with more efficient use of scan parameters and the use of "newer" image reconstruction techniques. Although iterative image reconstruction algorithms were first introduced in the 1970s, filtered back projection was chosen as the conventional image reconstruction technique because of its simplicity and faster reconstruction times. With subsequent advances in computational speed and power, iterative reconstruction techniques have reemerged and have shown the potential of radiation dose optimization without adversely influencing diagnostic image quality. In this article, we review the basic principles of different iterative reconstruction algorithms and their implementation for various clinical applications in cardiothoracic CT examinations for reducing radiation dose.
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Circulating biomarkers for the identification of patients with "actionable" nodules may increase screening uptake and decrease false-positive rates associated with low-dose computed tomography (LDCT). Novel autoantibody biomarkers...
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Circulating biomarkers for the identification of patients with "actionable" nodules may increase screening uptake and decrease false-positive rates associated with low-dose computed tomography (LDCT). Novel autoantibody biomarkers were identified utilizing a HuProt? protein microarray. Luminex assays were developed for the targeted measurement of identified biomarkers within a large Biomarker Development Cohort (n = 841). Each individual biomarker's performance was assessed. The Biomarker Development Cohort was split into three separate cohorts: Training, Validation 1, and Validation 2. Utilizing a Training cohort, a random forest model for identifying patients with "actionable" nodules from those with "non-actionable" nodules was built. The random forest model performance characteristics were determined for both a Validation 1 and the Validation 2 cohort. From these steps we have developed a risk-stratification method that assesses circulating levels of a panel of novel autoantibody biomarkers to serve as a companion diagnostic method for lung cancer screening.
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To assess relative safety and diagnostic performance of low- and standard-dose computed tomography (CT)-guided biopsy for pulmonary nodules (PNs).This was a single-center prospective randomized controlled trial (RCT). From June 20...
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To assess relative safety and diagnostic performance of low- and standard-dose computed tomography (CT)-guided biopsy for pulmonary nodules (PNs).This was a single-center prospective randomized controlled trial (RCT). From June 2020 to December 2020, consecutive patients with PNs were randomly assigned into low- or standard-dose groups. The primary outcome was diagnosis accuracy. The secondary outcomes included technical success, diagnostic yield, operation time, radiation dose, and biopsy-related complications. This RCT was registered on 3 January 2020 and listed within ClinicalTrials.gov (NCT04217655).Two hundred patients were randomly assigned to low-dose (n = 100) and standard-dose (n = 100) groups. All patients achieved the technical success of CT-guided biopsy and definite final diagnoses. No significant difference was found in operation time (n = 0.231) between the two groups. The mean dose-length product was markedly reduced within the low-dose group compared to the standard-dose group (31.5 vs. 333.5 mGy-cm, P < 0.001). The diagnostic yield, sensitivity, specificity, and accuracy of the low-dose group were 68%, 91.5%, 100%, and 94%, respectively. The diagnostic yield, sensitivity, specificity, and accuracy were 65%, 88.6%, 100%, and 92% in the standard-dose group. There was no significant difference observed in diagnostic yield (P = 0.653), diagnostic accuracy (P = 0.579), rates of pneumothorax (P = 0.836), and lung hemorrhage (P = 0.744) between the two groups.Compared with standard-dose CT-guided biopsy for PNs, low-dose CT can significantly reduce the radiation dose, while yielding comparable safety and diagnostic accuracy.
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Introduction: According to the American Urological Association imaging guidelines, patients presenting with renal colic should undergo low-dose (LD) rather than standard-dose (SD) noncontrast CT. The aim of the present study was t...
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Introduction: According to the American Urological Association imaging guidelines, patients presenting with renal colic should undergo low-dose (LD) rather than standard-dose (SD) noncontrast CT. The aim of the present study was to assess how often physicians ordered LD CT scans and to calculate mean effective radiation exposure (ERE) from CT scans from dose length products, and determine mean cumulative ERE over 1-year follow-up period.Methods: After obtaining ethics approval, a retrospective chart review was conducted for patients with renal colic presenting to the emergency department between August 1, 2015 and July 31, 2016 (Phase I) and between April 1, 2019 and October 1, 2019 (Phase II). All imaging studies performed within 1-year of initial presentation were cataloged.Results: In Phase I, 146 patients, with mean age of 51 years and mean body mass index (BMI) of 28.6 kg/m(2), underwent 220 CT scans. In Phase II, 225 patients, with mean age of 55 years and mean BMI of 26.7 kg/m(2), underwent 273 CT scans. Urologists were the only physicians ordering LD CT scans and they ordered significantly more LD than SD CT scans (71.3% vs 28.7%, p < 0.001). In Phase II, after revision of LD CT scan protocol in March 2019, the mean ERE per LD CT significantly decreased (6.5 vs 1.6 mSv, p < 0.001). In addition, there were significant differences in mean ERE from LD CT scans between two hospitals in the same health system (1.6 vs 7.8 mSv, p < 0.001). The mean cumulative ERE in Phase II over the 1-year period was 19.3 mSv, with 6.9% of patients exceeding 50 mSv.Conclusions: Although LD CT scans are being ordered, a small percentage of patients continue to exceed the 50 mSv annual threshold. It is important to keep track of mean ERE of LD CT scans and collaborate with medical physicists and the diagnostic imaging department to further refine LD CT scan protocols since not every low-dose is low-dose.
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