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Yasaka K, Takahashi MM, Kurokawa M, Kubo T, Watanabe Y, Saigusa H, Abe O. Transient interruption of contrast on CT pulmonary angiography: effect of mid-inspiratory vs. end-inspiratory respiration command. Emerg Radiol 2024; 31:331-340. [PMID: 38632154 PMCID: PMC11129981 DOI: 10.1007/s10140-024-02227-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/28/2024] [Indexed: 04/19/2024]
Abstract
PURPOSE To investigate the effects of mid-inspiratory respiration commands and other factors on transient interruption of contrast (TIC) incidence on CT pulmonary angiography. METHODS In this retrospective study, 824 patients (mean age, 66.1 ± 15.3 years; 342 males) who had undergone CT pulmonary angiography between January 2021 and February 2023 were included. Among them, 545 and 279 patients were scanned at end- and mid-inspiratory levels, respectively. By placing a circular region of interest, CT attenuation of the main pulmonary artery (CTMPA) was recorded. Associations between several factors, including patient age, body weight, sex, respiratory command vs. TIC and severe TIC incidence (defined as CTMPA < 200 and 150 HU, respectively), were assessed using logistic regression analyses with stepwise regression selection based on Akaike's information criterion. RESULTS Mid-inspiratory respiration command, in addition to patient age and lighter body weight, had negative association with the incidence of TIC. Only patient age, lighter body weight, female sex, and larger cardiothoracic ratio were negatively associated with severe TIC incidence. Mid-inspiratory respiration commands helped reduce TIC incidence among patients aged < 65 years (p = 0.039) and those with body weight ≥ 75 kg (p = 0.005) who were at high TIC risk. CONCLUSION Changing the respiratory command from end- to mid-inspiratory levels, as well as patient age and body weight, was significantly associated with TIC incidence.
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Affiliation(s)
- Koichiro Yasaka
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
| | - Masumi Mizuki Takahashi
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Mariko Kurokawa
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Takatoshi Kubo
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Yusuke Watanabe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Hiroyuki Saigusa
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
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Tan S, Hamarati LB, Rajiah PS, Le Gal G, Ko JP, Stojanovska J. CTA of Acute Pulmonary Embolism: Best Practices. Semin Roentgenol 2022; 57:313-323. [DOI: 10.1053/j.ro.2022.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/15/2022] [Accepted: 08/19/2022] [Indexed: 11/11/2022]
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Incidence of transient interruption of contrast (TIC) - A retrospective single-centre analysis in CT pulmonary angiography exams acquired during inspiratory breath-hold with the breathing command: "Please inspire gently!". PLoS One 2019; 14:e0210473. [PMID: 30653548 PMCID: PMC6336366 DOI: 10.1371/journal.pone.0210473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/24/2018] [Indexed: 11/29/2022] Open
Abstract
Objectives To assess the occurrence of transient interruption of contrast (TIC) phenomenon in pulmonary computed tomography angiography (CTPA) exams performed in inspiratory breath-hold after patients were told to inspire gently. Methods In this retrospective single-centre study, CTPA exams of 225 consecutive patients scanned on a 16-slice CT scanner system were analysed. A-priori to measurements, exams were screened for inadequate pulmonary artery contrast due to incorrect bolus tracking or failure of i.v. contrast administration. Those exams were excluded. Attenuation values in the thoracic aorta and in the pulmonary trunk were assessed in duplicate measurements (M1 and M2) and the aorto-pulmonary density ratio was calculated. An aorto-pulmonary ratio > 1 with still contrast inflow being visible within the superior vena cava was defined as TIC. Results 3 patients were excluded due to incorrect bolus tracking. Final analysis was performed in 222 patients (mean age 65 ± 19 years, range 18 to 99 years). Mean density in the pulmonary trunk was 275±17 HU, in the aorta 208 ± 15 HU. Mean aorto-pulmonary ratio was 0.81± 0.29. 48 patients (21.6%) had an aorto-pulmonary ratio >1. Correlation of mean aorto-pulmonary ratio and age was: -0.213 (p = 0.001). Age was not significantly different for an aorto-pulmonary ratio >1 vs. ≤1 (p = 0.122). Both in M1 and M2, 33/222 patients presented with absolute HU values of < 200 HU within the pulmonary artery. In M1 measurements, 24 of these 33 patients (72%) fulfilled TIC criteria (M2: 25/33 patients (75%)). Conclusions TIC is a common phenomenon in CTPA studies with inspiratory breath-hold commands after patients were told to inspire gently with an incidence of 22% in our retrospective cohort. Occurrence of TIC shows a significant negative correlation with increasing age and disproportionately often occurs in patients with lower absolute contrast density values within their pulmonary arteries.
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Improved Opacification of a Suboptimally Enhanced Pulmonary Artery in Chest CT: Experience Using a Dual-Layer Detector Spectral CT. AJR Am J Roentgenol 2018; 210:734-741. [PMID: 29446668 DOI: 10.2214/ajr.17.18537] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The objective of our study was to evaluate the quality of virtual monoenergetic imaging (VMI) from dual-layer detector spectral CT and the effect of virtual monoenergetic images obtained at low energies on the detection of pulmonary embolism (PE) in patients with a suboptimally enhanced pulmonary artery on chest CT. MATERIALS AND METHODS Of 1552 consecutive chest CT examinations performed with dual-layer detector spectral CT using a routine protocol with a tube voltage of 120 kVp, 79 examinations with suboptimal enhancement of the pulmonary artery (i.e., mean attenuation of pulmonary artery ≤ 180 HU) were included. The mean attenuation of the pulmonary artery, noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) of virtual monoenergetic images obtained at 40-200 keV were compared with those of the conventional 120-kVp images. The virtual monoenergetic images with the best CNR were compared with the 120-kVp images with regard to subjective image quality and diagnostic accuracy for detecting PE. RESULTS Sufficient attenuation of the pulmonary artery (> 180 HU) was obtained using VMI for 78 of the 79 examinations. The noise levels of the virtual monoenergetic images were gradually increased with decreasing energy level (i.e., kiloelectron volt setting). The CNR and SNR of virtual monoenergetic images at 40-65 keV were significantly higher (both, p < 0.001) than the CNR and SNR of the 120-kVp images. The CNR was the highest at 40 keV for all cases. Diagnostic accuracy for detecting PE was significantly higher for 40-keV images (reader 1: AUC = 0.992, p = 0.033; reader 2: AUC = 0.986, p = 0.043) than for 120-kVp images (reader 1, AUC = 0.911; reader 2, AUC = 0.933). The subjective quality was not different between these two images. CONCLUSION In chest CT examinations in which the pulmonary artery is suboptimally enhanced, obtaining virtual monoenergetic images at a low energy setting using dual-layer detector spectral CT allows sufficient attenuation of the pulmonary artery to be achieved while preserving image quality and increasing diagnostic performance for detecting PE.
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Virtual Monoenergetic Imaging and Iodine Perfusion Maps Improve Diagnostic Accuracy of Dual-Energy Computed Tomography Pulmonary Angiography With Suboptimal Contrast Attenuation. Invest Radiol 2017; 52:659-665. [DOI: 10.1097/rli.0000000000000387] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Takeda KA, Ishikawa WY, Silva CDS, Augusto F, Silva EFD, Tachibana A, Funari MBDG. The importance of apnea in patients undergoing angiography of thoracic vessels - a protocol for acute pulmonary thromboembolism research. EINSTEIN-SAO PAULO 2017; 15:241-242. [PMID: 28767926 PMCID: PMC5609625 DOI: 10.1590/s1679-45082017ai3884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 02/17/2017] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | - Fábio Augusto
- Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
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Yeo JH, Zhou L, Lim R. Indeterminate CT pulmonary angiogram: Why and does it matter? J Med Imaging Radiat Oncol 2016; 61:18-23. [PMID: 27470054 DOI: 10.1111/1754-9485.12500] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/18/2016] [Indexed: 11/30/2022]
Abstract
INTRODUCTION This study assessed the rate of indeterminate CT pulmonary angiogram (CTPA) in a general hospital and evaluated potential contributing factors to an indeterminate CTPA and patients' eventual clinical outcome. METHODS Four hundred and three consecutive CTPA and their finalised report from 01/08/2012 to 05/12/2012 at Waitemata DHB were reviewed retrospectively. Patient demographics, scan parameters and average Hounsfield unit (HU) of the main pulmonary trunk (PT) and likely cause of indeterminate study were documented. Studies were categorised into diagnostic, suboptimal or non-diagnostic studies. Univariate and multiple regression analyses were employed. RESULTS Six per cent (n = 24) of the studies were deemed indeterminate which included suboptimal and non-diagnostic studies. Seven pregnant patients were scanned during the study period and four of the seven studies were deemed indeterminate. In univariate analysis, predictors of indeterminate studies included 'weight' (P = 0.022), 'average HU of PT' (P < 0.0001) and 'effective dose' (P = 0.0003). In the multivariate logistic regression model, only 'average HU of PT' was associated with indeterminate studies (OR = 0.99, 95%CI: 0.99, 1.00). Twelve of 24 indeterminate studies had suboptimal pulmonary enhancement with causes including suboptimal timing of contrast bolus, hyperdynamic state due to pregnancy and transient interruption of contrast. Three patients had excessive noise due to body habitus. Eight studies had motion artefacts and one patient had left lower lobe pneumonia which decreased the accuracy. A third of the indeterminate studies were clinically considered as negative by referring clinicians. CONCLUSIONS Pulmonary trunk average Hounsfield unit is a predictor of indeterminate CT pulmonary angiogram.
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Affiliation(s)
- Ju Hee Yeo
- Department of Radiology, North Shore Hospital, Waitemata DHB, Auckland, New Zealand
| | - Lifeng Zhou
- Planning and Funding, Waitemata DHB, Auckland, New Zealand
| | - Remy Lim
- Department of Radiology, North Shore Hospital, Waitemata DHB, Auckland, New Zealand
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Influence of Respiratory Position on Contrast Attenuation in Pulmonary CT Angiography: A Prospective Randomized Clinical Trial. AJR Am J Roentgenol 2016; 206:481-6. [DOI: 10.2214/ajr.15.15176] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Meier A, Wurnig M, Desbiolles L, Leschka S, Frauenfelder T, Alkadhi H. Advanced virtual monoenergetic images: improving the contrast of dual-energy CT pulmonary angiography. Clin Radiol 2015; 70:1244-51. [DOI: 10.1016/j.crad.2015.06.094] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 06/15/2015] [Accepted: 06/25/2015] [Indexed: 11/25/2022]
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Suction/Inspiration against resistance or standardized Mueller maneuver : a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study. Eur Radiol 2015; 25:3133-42. [PMID: 26032878 DOI: 10.1007/s00330-015-3735-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/18/2015] [Accepted: 03/23/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. MATERIAL AND METHODS The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. RESULTS Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. CONCLUSION Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. KEY POINTS • Suction/Inspiration against resistance is promising to improve contrast density within the pulmonary artery. • Patients potentially suffering pulmonary embolism are able to follow suction/inspiration against resistance. • Contrast density after suction is superior in comparison to other breathing maneuvers.
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Gutzeit A, Roos JE, Hergan K, von Weymarn C, Wälti S, Reischauer C, Froehlich JM. Suction against resistance: a new breathing technique to significantly improve the blood flow ratio of the superior and inferior vena cava. Eur Radiol 2014; 24:3034-41. [PMID: 25103533 DOI: 10.1007/s00330-014-3328-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 06/23/2014] [Accepted: 07/08/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Optimal contrast within the pulmonary artery is achieved by the maximum amount of contrast-enhanced blood flowing through the superior vena cava (SVC), while minimum amounts of non-contrasted blood should originate from the inferior vena cava (IVC). This study aims to clarify whether "suction against resistance" might optimise this ratio. METHODS Phase-contrast pulse sequences on a 1.5T MRI magnet were used for flow quantification (mean flow (mL/s), stroke volume (Vol) in the SVC and IVC in volunteers. Different breathing manoeuvers were analysed repeatedly: free breathing; inspiration; expiration; suction against resistance, and Valsalva. To standardise breathing commands, volunteers performed suction and Valsalva manoeuvers with an MR-compatible manometer. RESULTS Suction against resistance was associated with a significant drop of the IVC/SVC flow quotient (1.63 [range 1.3-2.0] p < 0.05 at -10 mmHg and 1.48 [1.1-1.9] p < 0.01 at -20 mmHg) corresponding to increased blood flow from SVC and diminished flow originating from the IVC. The remaining breathing commands (free breathing 2.2; inspiration 2.4; expiration 2.4; Valsalva 10 mmHg 2.3; Valsalva 20 mmHg 2.6; and Valsalva 30 mmHg 2.2) showed no differences (p > 0.05). CONCLUSIONS Suction against resistance caused a significant drop in the IVC/SVC quotient. Theoretically, this breathing manoeuver might significantly improve the enhancement characteristics of CT angiography. KEY POINTS Suction provokes reduction in blood flow in the inferior vena cava. Ratio between the inferior and superior vena cava blood flow diminished during suction. Manometer used during breathing standardises MR phase-contrast blood flow measurements.
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Affiliation(s)
- Andreas Gutzeit
- Institute of Radiology and Nuclear Medicine, Clinical Research Unit of St. Anna Hospital Luzern, St. Anna Strasse 32, 6006, Luzern, Switzerland,
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Hamilton MCK, Mortimer AM, Hughes J. Re: Use of expiratory CT pulmonary angiography to reduce inspiration and breath-hold associated artefact: contrast dynamics and implications for scan protocol. A reply. Clin Radiol 2012; 68:e99-100. [PMID: 23219308 DOI: 10.1016/j.crad.2012.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Accepted: 10/31/2012] [Indexed: 12/01/2022]
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Arenas-Jiménez J, Bernabé-García J, García-Espasa C. Re: Use of expiratory CT pulmonary angiography to reduce inspiration and breath-hold associated artefact: contrast dynamics and implications for scan protocol. Clin Radiol 2012. [PMID: 23177654 DOI: 10.1016/j.crad.2012.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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