Radiology examination of increasing importance during pandemic: Low-dose chest CT; Diagnostic efficacy and exposure to ionizing radiation dose compared to standard-dose chest CT in COVID-19 cases

Background: Chest computed tomography (CT) scan is frequently used for diagnosis of coronavirus disease 2019 (COVID-19), especially in regions with limited availability of reverse-transcription polymerase chain reaction test (RT-PCR) test. Low-dose CT of chest offers acceptable image quality with lower radiation dose, particularly important in younger patients. Objectives: We have designed the current study to evaluate the diagnostic efficacy of low-dose chest CT versus early RT-PCR results, for triage of COVID-19 patients. Patients and Methods: From February 20 to April 15, 2020, 163 patients including 100 males (61.3%) with the median age of 65 years (21 to 97), who underwent both RT-PCR and chest CT were registered in the study. Low-dose chest CT protocol was applied with parameters modified from the lung cancer screening protocol. The accuracy of low-dose chest CT for COVID-19 diagnosis was evaluated, considering first RT-PCR results as reference. Results: Of 163 patients, 89 cases (54.6%) were presented with positive initial RT-PCR result. Lymphocyte percentage and lymphocyte count were significantly lower in the positive RT-PCR group (15% versus 19%, and 0.98 vs. 1.3, respectively); while, erythrocyte sedimentation rate (ESR) was significantly higher (53 vs. 22). Positive chest CT findings were present in 133/163 cases (81.6%). The sensitivity, specificity, positive and negative predictive values (PPV and NPV) and accuracy of low-dose chest CT scan were 96.6% (95% confidence interval [CI], 90% - 99%), 36.5% (95% CI, 26% - 49%), 64.7% (95% CI, 56% - 73%), 90% (95% CI, 72% - 97%) and 69.3% (95% CI, 61% - 76%), respectively based on positive RT-PCR results. Conclusion: Low-dose chest CT scan provides both high sensitivity and negative predictive value in diagnosing COVID-19 compared to initial RT-PCR as the gold standard. It can be used as an alternate to standard-dose CT scan in areas with high prevalence of COVID-19 disease and limited availability of RT-PCR for early triage.

Download Full-text

A review on chest CT scanning parameters implemented in COVID-19 patients: bringing low-dose CT protocols into play

Egyptian Journal of Radiology and Nuclear Medicine ◽

10.1186/s43055-020-00400-1 ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Javid Azadbakht ◽

Daryoush Khoramian ◽

Zahra Sadat Lajevardi ◽

Fateme Elikaii ◽

Amir Hossein Aflatoonian ◽

...

Keyword(s):

Radiation Dose ◽

Ct Scan ◽

Low Dose ◽

Standard Dose ◽

Ct Scanning ◽

Chest Ct ◽

Main Body ◽

Low Dose Ct ◽

Ct Protocol ◽

Chest Ct Scan

Abstract Background This study aims to review chest computed tomography (CT) scanning parameters which are utilized to evaluate patients for COVID-19-induced pneumonia. Also, some of radiation dose reduction techniques in CT would be mentioned, because using these techniques or low-dose protocol can decrease the radiation burden on the population. Main body Chest CT scan can play a key diagnostic role in COVID-19 patients. Additionally, it can be useful to monitor imaging changes during treatment. However, CT scan overuse during the COVID-19 pandemic raises concerns about radiation-induced adverse effects, both in patients and healthcare workers. Conclusion By evaluating the CT scanning parameters used in several studies, one can find the necessity for optimizing these parameters. It has been found that chest CT scan taken using low-dose CT protocol is a reliable diagnostic tool to detect COVID-19 pneumonia in daily practice. Moreover, the low-dose chest CT protocol results in a remarkable reduction (up to 89%) in the radiation dose compared to the standard-dose protocol, not lowering diagnostic accuracy of COVID-19-induced pneumonia in CT images. Therefore, its employment in the era of the COVID-19 pandemic is highly recommended.

Download Full-text

Effects of exposure to low-dose ionizing radiation on changing platelets: a prospective cohort study

Environmental Health and Preventive Medicine ◽

10.1186/s12199-021-00939-z ◽

2021 ◽

Vol 26 (1) ◽

Author(s):

Ning Liu ◽

Yang Peng ◽

Xinguang Zhong ◽

Zheng Ma ◽

Suiping He ◽

...

Keyword(s):

Radiation Dose ◽

Ionizing Radiation ◽

Dose Response ◽

Low Dose ◽

Linear Trend ◽

Hematological Parameters ◽

Response Relationship ◽

Dose Response Relationship ◽

Spline Models ◽

Cumulative Radiation Dose

Abstract Background Numerous studies have concentrated on high-dose radiation exposed accidentally or through therapy, and few involve low-dose occupational exposure, to investigate the correlation between low-dose ionizing radiation and changing hematological parameters among medical workers. Methods Using a prospective cohort study design, we collected health examination reports and personal dose monitoring data from medical workers and used Poisson regression and restricted cubic spline models to assess the correlation between changing hematological parameters and cumulative radiation dose and determine the dose-response relationship. Results We observed that changing platelet of 1265 medical workers followed up was statistically different among the cumulative dose groups (P = 0.010). Although the linear trend tested was not statistically significant (Ptrend = 0.258), the non-linear trend tested was statistically significant (Pnon-linear = 0.007). Overall, there was a correlation between changing platelets and cumulative radiation dose (a change of βa 0.008 × 109/L during biennially after adjusting for gender, age at baseline, service at baseline, occupation, medical level, and smoking habits; 95% confidence interval [CI] = 0.003,0.014 × 109/L). Moreover, we also found positive first and then negative dose-response relationships between cumulative radiation dose and changing platelets by restricted cubic spline models, while there were negative patterns of the baseline service not less than 10 years (− 0.015 × 109/L, 95% CI = − 0.024, − 0.007 × 109/L) and radiation nurses(− 0.033 × 109/L, 95% CI = − 0.049, − 0.016 × 109/L). Conclusion We concluded that although the exposure dose was below the limit, medical workers exposed to low-dose ionizing radiation for a short period of time might have increased first and then decreased platelets, and there was a dose-response relationship between the cumulative radiation dose and platelets changing.

Download Full-text

Implementation of ultra-low-dose lung protocols in CT-guided lung biopsies: feasibility and safety in the clinical setting

Journal of International Medical Research ◽

10.1177/0300060517712165 ◽

2017 ◽

Vol 45 (6) ◽

pp. 2101-2109 ◽

Cited By ~ 3

Author(s):

Barbara K Frisch ◽

Karin Slebocki ◽

Kamal Mammadov ◽

Michael Puesken ◽

Ingrid Becker ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Low Dose ◽

Standard Dose ◽

Complication Rates ◽

Dose Length Product ◽

Ct Guided ◽

Total Radiation Dose ◽

Lung Biopsies ◽

Histological Results

Objective To evaluate the use of ultra-low-dose computed tomography (ULDCT) for CT-guided lung biopsy versus standard-dose CT (SDCT). Methods CT-guided lung biopsies from 115 patients (50 ULDCT, 65 SDCT) were analyzed retrospectively. SDCT settings were 120 kVp with automatic mAs modulation. ULDCT settings were 80 kVp with fixed exposure (20 mAs). Two radiologists evaluated image quality (i.e., needle artifacts, lesion contouring, vessel recognition, visibility of interlobar fissures). Complications and histological results were also evaluated. Results ULDCT was considered feasible for all lung interventions, showing the same diagnostic accuracy as SDCT. Its mean total radiation dose (dose–length product) was significantly reduced to 34 mGy-cm (SDCT 426 mGy-cm). Image quality and complication rates ( P = 0.469) were consistent. Conclusions ULDCT for CT-guided lung biopsies appears safe and accurate, with a significantly reduced radiation dose. We therefore recommend routine clinical use of ULDCT for the benefit of patients and interventionalists.

Download Full-text

Low-Dose Computed Tomography for the Optimization of Radiation Dose Exposure in Patients with Crohn’s Disease

Gastroenterology Research and Practice ◽

10.1155/2018/1768716 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Richard G. Kavanagh ◽

John O’Grady ◽

Brian W. Carey ◽

Patrick D. McLaughlin ◽

Siobhan B. O’Neill ◽

...

Keyword(s):

Computed Tomography ◽

Crohn’S Disease ◽

Image Quality ◽

Crohn's Disease ◽

Radiation Dose ◽

Ionizing Radiation ◽

Low Dose ◽

Radiation Doses ◽

Radiation Dose Exposure ◽

Ct Technology

Magnetic resonance imaging (MRI) is the mainstay method for the radiological imaging of the small bowel in patients with inflammatory bowel disease without the use of ionizing radiation. There are circumstances where imaging using ionizing radiation is required, particularly in the acute setting. This usually takes the form of computed tomography (CT). There has been a significant increase in the utilization of computed tomography (CT) for patients with Crohn’s disease as patients are frequently diagnosed at a relatively young age and require repeated imaging. Between seven and eleven percent of patients with IBD are exposed to high cumulative effective radiation doses (CEDs) (>35–75 mSv), mostly patients with Crohn’s disease (Newnham E 2007, Levi Z 2009, Hou JK 2014, Estay C 2015). This is primarily due to the more widespread and repeated use of CT, which accounts for 77% of radiation dose exposure amongst patients with Crohn’s disease (Desmond et al., 2008). Reports of the projected cancer risks from the increasing CT use (Berrington et al., 2007) have led to increased patient awareness regarding the potential health risks from ionizing radiation (Coakley et al., 2011). Our responsibilities as physicians caring for these patients include education regarding radiation risk and, when an investigation that utilizes ionizing radiation is required, to keep radiation doses as low as reasonably achievable: the “ALARA” principle. Recent advances in CT technology have facilitated substantial radiation dose reductions in many clinical settings, and several studies have demonstrated significantly decreased radiation doses in Crohn’s disease patients while maintaining diagnostic image quality. However, there is a balance to be struck between reducing radiation exposure and maintaining satisfactory image quality; if radiation dose is reduced excessively, the resulting CT images can be of poor quality and may be nondiagnostic. In this paper, we summarize the available evidence related to imaging of Crohn’s disease, radiation exposure, and risk, and we report recent advances in low-dose CT technology that have particular relevance.

Download Full-text

Radiation Dose Optimization in Pediatric Chest CT: Major Indicators of Dose Exposure in 1695 CT Scans over Seven Years

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren ◽

10.1055/a-0628-7222 ◽

2018 ◽

Vol 190 (12) ◽

pp. 1131-1140 ◽

Cited By ~ 3

Author(s):

Michael Esser ◽

Sabine Hess ◽

Matthias Teufel ◽

Mareen Kraus ◽

Sven Schneeweiß ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Low Dose ◽

Chest Ct ◽

Dose Optimization ◽

High Dose ◽

High Pitch ◽

Pediatric Chest ◽

Radiation Dose Optimization

Purpose To analyze possible influencing factors on radiation exposure in pediatric chest CT using different approaches for radiation dose optimization and to determine major indicators for dose development. Materials and Methods In this retrospective study at a clinic with maximum care facilities including pediatric radiology, 1695 chest CT examinations in 768 patients (median age: 10 years; range: 2 days to 17.9 years) were analyzed. Volume CT dose indices, effective dose, size-specific dose estimate, automatic dose modulation (AEC), and high-pitch protocols (pitch ≥ 3.0) were evaluated by univariate analysis. The image quality of low-dose examinations was compared to higher dose protocols by non-inferiority testing. Results Median dose-specific values annually decreased by an average of 12 %. High-pitch mode (n = 414) resulted in lower dose parameters (p < 0.001). In unenhanced CT, AEC delivered higher dose values compared to scans with fixed parameters (p < 0.001). In contrast-enhanced CT, the use of AEC yielded a significantly lower radiation dose only in patients older than 16 years (p = 0.04). In the age group 6 to 15 years, the values were higher (p < 0.001). The diagnostic image quality of low-dose scans was non-inferior to high-dose scans (2.18 vs. 2.14). Conclusion Radiation dose of chest CT was reduced without loss of image quality in the last decade. High-pitch scanning was an independent factor in this context. Dose reduction by AEC was limited and only relevant for patients over 16 years. Key Points Citation Format

Download Full-text

The feasibility of low dose chest CT acquisition protocol for the imaging of COVID-19 pneumonia

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405617666210623124108 ◽

2021 ◽

Vol 17 ◽

Author(s):

Eray Atlı ◽

Sadık Ahmet Uyanık ◽

Umut Öğüşlü ◽

Halime Çevik Cenkeri ◽

Birnur Yılmaz ◽

...

Keyword(s):

Radiation Dose ◽

Dose Reduction ◽

Low Dose ◽

Chest Ct ◽

Radiation Dose Reduction ◽

Control Group ◽

Effective Diameter ◽

Suspected Case ◽

Diagnostic Confidence ◽

Acquisition Protocol

Objective: To investigate the feasibility of low dose chest CT acquisition protocol for the imaging of either the confirmed case of COVID-19 disease or the suspected case of this disease in adults. Method: In this retrospective case-control study, the study group consisted of 141 patients who were imaged with low dose chest CT acquisition protocol. The control group consisted of 92 patients who were imaged with the standard protocol. Anteroposterior and lateral diameters of chest, effective diameter and scan length, qualitative and quantitative noise levels, volumetric CT dose index (CTDIvol), dose length product (DLP), and size-specific dose estimations were compared between groups. Results: Radiation dose reduction by nearly 90% (CTDIvol and DLP values 1.06 mGy and 40.3 mGy.cm vs. 8.07 mGy and 330 mGy.cm, p < 0.001, respectively) was achieved with the use of low dose acquisition chest CT protocol. Despite higher image noise with low dose acquisition protocol, no significant effect on diagnostic confidence was encountered. Cardiac and diaphragm movement-related artifacts were similar in both groups (p = 0.275). Interobserver agreement was very good in terms of diagnostic confidence assessment. Conclusion: For the imaging of either the confirmed case of COVID-19 related pneumonia or the suspected case of this disease in adults, low dose chest CT acquisition protocol provides remarkable radiation dose reduction without adversely affecting image quality and diagnostic confidence.

Download Full-text