Optimizing Pulmonary Embolism Computed Tomography in the Age of Individualized Medicine

Hendriks, Babs M. F.; Eijsvoogel, Nienke G.; Kok, Madeleine; Martens, Bibi; Wildberger, Joachim E.; Das, Marco

doi:10.1097/rli.0000000000000443

Cited by 29 publications

(25 citation statements)

References 40 publications

(48 reference statements)

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“…1). Image quality was assessed by calculating contrast-to-noise ratio (CNR) [35]. This study refers to enhancement of 200 HU and 120 kVp [3] as reference level.…”

Section: Image Quality Assessmentmentioning

confidence: 99%

Impact of iodine concentration and scan parameters on image quality, contrast enhancement and radiation dose in thoracic CT

et al. 2020

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Background We investigated the impact of varying contrast medium (CM) densities and x-ray tube potentials on contrast enhancement (CE), image quality and radiation dose in thoracic computed tomography (CT) using two different scanning techniques. Methods Seven plastic tubes containing seven different CM densities ranging from of 0 to 600 HU were positioned inside a commercial chest phantom with padding, representing three different patient sizes. Helical scans of the phantom in single-source mode were obtained with varying tube potentials from 70 to 140 kVp. A constant volume CT dose index (CTDIvol) depending on phantom size and automatic dose modulation was tested. CE (HU) and image quality (contrast-to-noise ratio, CNR) were measured for all combinations of CM density and tube potential. A reference threshold of CE and kVp was defined as ≥ 200 HU and 120 kVp. Results For the medium-sized phantom, with a specific CE of 100–600 HU, the diagnostic CE (200 HU) at 70 kVp was ~ 90% higher than at 120 kVp, for both scan techniques (p < 0.001). Changes in CM density/specific HU together with lower kVp resulted in significantly higher CE and CNR (p < 0.001). When changing only the kVp, no statistically significant differences were observed in CE or CNR (p ≥ 0.094), using both dose modulation and constant CTDIvol. Conclusions For thoracic CT, diagnostic CE (≥ 200 HU) and maintained CNR were achieved by using lower CM density in combination with lower tube potential (< 120 kVp), independently of phantom size.

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“…1). Image quality was assessed by calculating contrast-to-noise ratio (CNR) [35]. This study refers to enhancement of 200 HU and 120 kVp [3] as reference level.…”

Section: Image Quality Assessmentmentioning

confidence: 99%

Impact of iodine concentration and scan parameters on image quality, contrast enhancement and radiation dose in thoracic CT

et al. 2020

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“…On a per-examination basis, we visually evaluated the enhancement quality of the pulmonary arteries by the IV-injected contrast agent using a 4-point Likert scale: 0 = non-diagnostic (excluded), 1 = diagnostic image with presence of severe artifacts, 2 = good image quality with minor artifacts, and 3 = excellent image quality with no relevant artifacts [17]. The examinations were then classified as positive or negative for acute PE.…”

Section: Image Analysismentioning

confidence: 99%

Pulmonary embolism during pregnancy: a 17-year single-center retrospective MDCT pulmonary angiography study

et al. 2019

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Objectives To determine the prevalence of pulmonary embolism (PE) and alternative diagnoses detected by computed tomography pulmonary angiography (CTPA) in pregnant women; and to assess changes over time regarding radiation dose, technical quality, and examination frequency. Materials and methods This retrospective study included all pregnant women referred for CTPA due to clinically suspected PE over 17 years. Two blinded radiologists reviewed the CTPAs in consensus with regard to PE, alternative diagnoses, and technical quality. We retrieved patient data regarding radiation dose metrics and associated clinical and laboratory parameters. Subgroup comparisons were performed (Wilcoxon and Kruskal-Wallis tests). Results Of the 237 identified patients, 8 (3.3%) were excluded due to inadequate technical CTPA quality, and 229 patients were analyzed (mean age, 31.7 years; mean gestational age, 28 ± 7 weeks). The four different CT systems used over the study period had similar technical quality (p = 0.28). Of 229 patients 16 (7%) patients had PE, 144 (62.9%) had no abnormal findings, and 69 (30.1%) had an alternative diagnosis (consolidation, other pulmonary opacities, pleural effusion, and basal atelectasis). Gestational age, symptoms, and D-dimer levels were not significantly different between patients with or without PE (p > 0.05). Over time, radiation dose exposure decreased by 30% (p < 0.001), while the number of annual examinations increased by > 4-folds. Conclusions In pregnant women, CTPA rarely indicates PE and more often shows alternative diagnoses. Over 17 years, the use of CTPA in pregnancy has notably increased, while the radiation dose exposure has decreased by one third. Key Points • The use of CTPA in pregnancy has steadily risen over the last 17 years • In pregnant women, CTPA rarely reveals PE and more often shows alternative diagnoses • Recent technical improvements have substantially decreased the radiation dose exposure inherent in CTPA without reducing diagnostic image quality

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“…31,38 Automatic kilovoltage peak selection in relation to patient size is an available function on newer CT scanners and has been shown to reduce the radiation dose. 31,32,39 In one study, the use of this function in CTPA resulted in a selected tube potential of 70 to 90 kVp (80 kVp in most cases). 29 The use of dual energy in CTPA reportedly provides similar image quality at lower radiation doses.…”

Section: Introductionmentioning

confidence: 99%

Individualization of computed tomography protocols for suspected pulmonary embolism: a national investigation of routines

et al. 2020

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Objective: Given the extensive use of computed tomography (CT) in radiation-sensitive patients such as pregnant and pediatric patients, and considering the importance of tailoring CT protocols to patient characteristics for both the radiation dose and image quality, this study was performed to investigate the extent to which individualization of CT protocols is practiced across Norway. Methods: This cross-sectional study involved collection of CT protocols and administration of a mini-questionnaire to obtain additional information about how CT examinations are individualized. All public hospitals performing CT to detect pulmonary embolism were invited, and 41% participated. Results: Tailoring a standard protocol to different patient groups was more common than using dedicated protocols. Most of the available radiation dose-reduction approaches were used. However, implementation of these strategies was not systematic. Children and pregnant patients were examined without using dedicated CT protocols or by using protocol adjustments focusing on radiation dose reduction in 30% and 39% of the hospitals, respectively. Conclusion: Practice optimization is needed, especially the development of dedicated CT protocols or guidelines that tailor the existing protocol to pediatric and pregnant patients. Practice might benefit from a more systematic approach to individualization of CT examinations, such as inserting tailoring instructions into CT protocols.

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Optimizing Pulmonary Embolism Computed Tomography in the Age of Individualized Medicine

Cited by 29 publications

References 40 publications

Impact of iodine concentration and scan parameters on image quality, contrast enhancement and radiation dose in thoracic CT

Impact of iodine concentration and scan parameters on image quality, contrast enhancement and radiation dose in thoracic CT

Pulmonary embolism during pregnancy: a 17-year single-center retrospective MDCT pulmonary angiography study

Individualization of computed tomography protocols for suspected pulmonary embolism: a national investigation of routines

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