1
|
Gillespie CD, Yates A, Hughes M, Ewins K, McMahon G, Hynes J, Murphy MC, Galligan M, Vencken S, Alih E, Varden J, Donnelly J, Bolster F, Rowan M, Foley S, NíAinle F, MacMahon PJ. Validating the safety of low-dose CTPA in pregnancy: results from the OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) Study. Eur Radiol 2024; 34:4864-4873. [PMID: 38296849 DOI: 10.1007/s00330-024-10593-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/23/2023] [Accepted: 12/27/2023] [Indexed: 02/02/2024]
Abstract
BACKGROUND Pulmonary embolism (PE) is a leading cause of pregnancy-related mortality. CT pulmonary angiogram (CTPA) is the first-line advanced imaging modality for suspected PE in pregnancy at institutes offering low-dose techniques; however, a protocol balancing safety with low dose remains undefined. The wide range of CTPA doses reported in pregnancy suggests a lack of confidence in implementing low-dose techniques in this group. PURPOSE To define and validate the safety, radiation dose and image quality of a low-dose CTPA protocol optimised for pregnancy. MATERIALS AND METHODS The OPTICA study is a prospective observational study. Pregnant study participants with suspected PE underwent the same CTPA protocol between May 2018 and February 2022. The primary outcome, CTPA safety, was judged by the reference standard; the 3-month incidence of venous thromboembolism (VTE) in study participants with a negative index CTPA. Secondary outcomes defined radiation dose and image quality. Absorbed breast, maternal effective and fetal doses were estimated by Monte-Carlo simulation on gestation-matched phantoms. Image quality was assessed by signal-to-noise and contrast-to-noise ratios and a Likert score for pulmonary arterial enhancement. RESULTS A total of 116 CTPAs were performed in 113 pregnant women of which 16 CTPAs were excluded. PE was diagnosed on 1 CTPA and out-ruled in 99. The incidence of recurrent symptomatic VTE was 0.0% (one-sided 95% CI, 2.66%) at follow-up. The mean absorbed breast dose was 2.9 ± 2.1mGy, uterine/fetal dose was 0.1 ± 0.2mGy and maternal effective dose was 1.4 ± 0.9mSv. Signal-to-noise ratio (SNR) was 11.9 ± 3.7. Contrast-to-noise ratio (CNR) was 10.4 ± 3.5. CONCLUSION The OPTICA CTPA protocol safely excluded PE in pregnant women across all trimesters, with low fetal and maternal radiation. CLINICAL RELEVANCE OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) is the first prospective study to define the achievable radiation dose, image-quality and safety of a low-dose CT pulmonary angiogram protocol optimised for pregnancy (NCT04179487). It provides the current benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population. KEY POINTS • Despite the increased use of CT pulmonary angiogram in pregnancy, an optimised low-dose protocol has not been defined and reported doses in pregnancy continue to vary widely. • The OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) study prospectively defines the achievable dose, image quality and safety of a low-dose CT pulmonary angiogram protocol using widely available technology. • OPTICA provides a benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population.
Collapse
Affiliation(s)
- Ciara D Gillespie
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland.
| | - Andrew Yates
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland
| | - Mark Hughes
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland
| | - Karl Ewins
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, D07 R2WY, Ireland
| | - Gabriella McMahon
- Department of Obstetrics, Rotunda Hospital, Dublin, D01 P5W9, Ireland
| | - John Hynes
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland
| | - Mark C Murphy
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland
| | - Marie Galligan
- Clinical Research Centre, School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Sebastian Vencken
- Clinical Research Centre, School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Ekele Alih
- Clinical Research Centre, School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - John Varden
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland
| | - Jennifer Donnelly
- Department of Obstetrics, Rotunda Hospital, Dublin, D01 P5W9, Ireland
- School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Ferdia Bolster
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland
- School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Michael Rowan
- Department of Medical Physics, St James Hospital, Dublin, D08 NHY1, Ireland
| | - Shane Foley
- Radiography & Diagnostic Imaging, School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Fionnuala NíAinle
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, D07 R2WY, Ireland
- School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Peter J MacMahon
- Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland
- School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| |
Collapse
|
2
|
Gong H, Peng L, Du X, An J, Peng R, Guo R, Ma X, Xiong S, Ma Q, Zhang G, Ma J. Artificial Intelligence Iterative Reconstruction in Computed Tomography Angiography: An Evaluation on Pulmonary Arteries and Aorta With Routine Dose Settings. J Comput Assist Tomogr 2024; 48:244-250. [PMID: 37657068 DOI: 10.1097/rct.0000000000001542] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
OBJECTIVE The objective of this study is to investigate whether a newly introduced deep learning-based iterative reconstruction algorithm, namely, the artificial intelligence iterative reconstruction (AIIR), has a clinical value in computed tomography angiography (CTA), especially for visualizing vascular structures and related lesions, with routine dose settings. METHODS A total of 63 patients were retrospectively collected from the triple rule-out CTA examinations, where both pulmonary and aortic data were available for each patient and were taken as the example for investigation. The images were reconstructed using the filtered back projection (FBP), hybrid iterative reconstruction (HIR), and the AIIR. The visibility of vasculature and pulmonary emboli and the general image quality were assessed. RESULTS Artificial intelligence iterative reconstruction resulted in significantly ( P < 0.001) lower noise as well as higher signal-to-noise ratio and contrast-to-noise ratio compared with FBP and HIR. Besides, AIIR achieved the highest subjective scores on general image quality ( P < 0.05). For the vasculature visibility, AIIR offered the best vessel conspicuity, especially for the small vessels ( P < 0.05). Also, >90% of emboli on the AIIR images were graded as sharp (score 5), whereas <15% of emboli on FBP and HIR images were scored 5. CONCLUSION As demonstrated for pulmonary and aortic CTAs, AIIR improves the image quality and offers a better depiction for vascular structures compared with FBP and HIR. The visibility of the pulmonary emboli was also increased by AIIR.
Collapse
Affiliation(s)
- Huan Gong
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | | | - Xiangdong Du
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | - Jiajia An
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | - Rui Peng
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | - Rui Guo
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | - Xu Ma
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | - Sining Xiong
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | - Qin Ma
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| | | | - Jing Ma
- From the Department of Radiology, The Second Affiliated Hospital of Shihezi University School of Medicine, Urumqi
| |
Collapse
|
3
|
Gillespie CD, Yates A, Murphy MC, Hughes M, Ewins K, NíAinle F, Bolster F, Rowan M, Foley S, MacMahon PJ. Breast Shielding Combined With an Optimized Computed Tomography Pulmonary Angiography Pregnancy Protocol: A Special Use-Case for Shielding? J Thorac Imaging 2023; 38:36-43. [PMID: 36162076 DOI: 10.1097/rti.0000000000000677] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To determine the impact of breast shields on breast dose and image quality when combined with a low-dose computed tomography pulmonary angiography (CTPA) protocol for pregnancy. METHODS A low-dose CTPA protocol, with and without breast shields, was evaluated by anthropomorphic phantom and 20 prospectively recruited pregnant participants from January to October 2019. Thermoluminescent dosimeters measured surface and absorbed breast dose in the phantom and surface breast dose in participants. The Monte-Carlo method estimated the absorbed breast dose in participants. Image quality was assessed quantitatively by regions of interest analysis and subjectively by the Likert scale. Doses and image quality for CTPA alone were compared with CTPA with breast shields. RESULTS Mean surface and absorbed breast dose for CTPA alone were 1.3±0.4 and 2.8±1.5 mGy in participants, and 1.5±0.7 and 1.6±0.6 mGy in the phantom. Shielding reduced surface breast dose to 0.5±0.3 and 0.7±0.2 mGy in the phantom (66%) and study participants (48%), respectively. Absorbed breast dose reduced to 0.9±0.5 mGy (46%) in the phantom.Noise increased with breast shields at lower kV settings (80 to 100 kV) in the phantom; however, in study participants there was no significant difference between shield and no-shield groups for main pulmonary artery noise (no-shield: 34±9.8, shield: 36.3±7.2, P =0.56), SNR (no-shield: 11.2±3.7, shield: 10.8±2.6, P =0.74) or contrast-to-noise ratio (no-shield: 10.0±3.3, shield: 9.3±2.4, P =0.6). Median subjective image quality scores were comparable (no-shield: 4.0, interquartile range: 3.5 to 4.4, shield: 4.3, interquartile range: 4.0 to 4.5). CONCLUSION Combining low-dose CTPA with breast shields confers additional breast-dose savings without impacting image quality and yields breast doses approaching those of low-dose scintigraphy, suggesting breast shields play a role in protocol optimization for select groups.
Collapse
Affiliation(s)
| | | | | | | | - Karl Ewins
- Haematology, Mater Misericordiae University Hospital
| | | | - Ferdia Bolster
- Departments of Radiology
- School of Medicine, University College Dublin
| | - Michael Rowan
- Department of Medical Physics, St James Hospital, Dublin, Ireland
| | - Shane Foley
- Radiography & Diagnostic Imaging, School of Medicine, University College Dublin
| | - Peter J MacMahon
- Departments of Radiology
- School of Medicine, University College Dublin
| |
Collapse
|
4
|
Zhao R, Sui X, Qin R, Du H, Song L, Tian D, Wang J, Lu X, Wang Y, Song W, Jin Z. Can deep learning improve image quality of low-dose CT: a prospective study in interstitial lung disease. Eur Radiol 2022; 32:8140-8151. [PMID: 35748899 DOI: 10.1007/s00330-022-08870-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/11/2022] [Accepted: 05/10/2022] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To investigate whether deep learning reconstruction (DLR) could keep image quality and reduce radiation dose in interstitial lung disease (ILD) patients compared with HRCT reconstructed with hybrid iterative reconstruction (hybrid-IR). METHODS Seventy ILD patients were prospectively enrolled and underwent HRCT (120 kVp, automatic tube current) and LDCT (120 kVp, 30 mAs) scans. HRCT images were reconstructed with hybrid-IR (Adaptive Iterative Dose Reduction 3-Dimensional [AIDR3D], standard-setting); LDCT images were reconstructed with DLR (Advanced Intelligence Clear-IQ Engine [AiCE], lung/bone, mild/standard/strong setting). Image noise, streak artifact, overall image quality, and visualization of normal and abnormal features of ILD were evaluated. RESULTS The mean radiation dose of LDCT was 38% of HRCT. Objective image noise of reconstructed LDCT images was 33.6 to 111.3% of HRCT, and signal-to-noise ratio (SNR) was 0.9 to 3.1 times of the latter (p < 0.001). LDCT-AiCE was not significantly different from or even better than HRCT in overall image quality and visualization of normal lung structures. LDCT-AiCE (lung, mild/standard/strong) showed progressively better recognition of ground glass opacity than HRCT-AIDR3D (p < 0.05, p < 0.01, p < 0.001), and LDCT-AiCE (lung, mild/standard/strong; bone, mild) was superior to HRCT-AIDR3D in visualization of architectural distortion (p < 0.01, p < 0.01, p < 0.01; p < 0.05). LDCT-AiCE (bone, strong) was better than HRCT-AIDR3D in the assessment of bronchiectasis and/or bronchiolectasis (p < 0.05). LDCT-AiCE (bone, mild/standard/strong) was significantly better at the visualization of honeycombing than HRCT-AIDR3D (p < 0.05, p < 0.05, p < 0.01). CONCLUSION Deep learning reconstruction could effectively reduce radiation dose and keep image quality in ILD patients compared to HRCT with hybrid-IR. KEY POINTS • Deep learning reconstruction was a novel image reconstruction algorithm based on deep convolutional neural networks. It was applied in chest CT studies and received auspicious results. • HRCT plays an essential role in the whole process of diagnosis, treatment efficacy evaluation, and follow-ups for interstitial lung disease patients. However, cumulative radiation exposure could increase the risks of cancer. • Deep learning reconstruction method could effectively reduce the radiation dose and keep the image quality compared with HRCT reconstructed with hybrid iterative reconstruction in patients with interstitial lung disease.
Collapse
Affiliation(s)
- Ruijie Zhao
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Xin Sui
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Ruiyao Qin
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Huayang Du
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Lan Song
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Duxue Tian
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Jinhua Wang
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Xiaoping Lu
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Yun Wang
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China
| | - Wei Song
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China.
| | - Zhengyu Jin
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, 100730, China.
| |
Collapse
|
5
|
Masuda S, Yamada Y, Minamishima K, Owaki Y, Yamazaki A, Jinzaki M. Impact of noise reduction on radiation dose reduction potential of virtual monochromatic spectral images: Comparison of phantom images with conventional 120 kVp images using deep learning image reconstruction and hybrid iterative reconstruction. Eur J Radiol 2022; 149:110198. [DOI: 10.1016/j.ejrad.2022.110198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/18/2021] [Accepted: 02/02/2022] [Indexed: 01/15/2023]
|
6
|
Yue W, Yang W, peng H, Zhong Feng N, Hong Jie H. Comparative study of the image quality of twin beam dual energy and single energy carotid CT angiography. Eur J Radiol 2022; 148:110160. [DOI: 10.1016/j.ejrad.2022.110160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/18/2021] [Accepted: 01/12/2022] [Indexed: 12/14/2022]
|
7
|
Task-based assessment on various optimization protocols of computed tomography Pulmonary Angiography examination. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109692] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
8
|
Diagnostic Performance of a Contrast-Enhanced Ultra-Low-Dose High-Pitch CT Protocol with Reduced Scan Range for Detection of Pulmonary Embolisms. Diagnostics (Basel) 2021; 11:diagnostics11071251. [PMID: 34359338 PMCID: PMC8304674 DOI: 10.3390/diagnostics11071251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/05/2021] [Accepted: 07/08/2021] [Indexed: 11/16/2022] Open
Abstract
(1) Background: To evaluate the diagnostic performance of a simulated ultra-low-dose (ULD), high-pitch computed tomography pulmonary angiography (CTPA) protocol with low tube current (mAs) and reduced scan range for detection of pulmonary embolisms (PE). (2) Methods: We retrospectively included 130 consecutive patients (64 ± 16 years, 69 female) who underwent clinically indicated high-pitch CTPA examination for suspected acute PE on a 3rd generation dual-source CT scanner (SOMATOM FORCE, Siemens Healthineers, Forchheim, Germany). ULD datasets with a realistic simulation of 25% mAs, reduced scan range (aortic arch-basal pericardium), and Advanced Modeled Iterative Reconstruction (ADMIRE®, Siemens Healthineers, Forchheim, Germany) strength 5 were created. The effective radiation dose (ED) of both datasets (standard and ULD) was estimated using a dedicated dosimetry software solution. Subjective image quality and diagnostic confidence were evaluated independently by three reviewers using a 5-point Likert scale. Objective image quality was compared using noise measurements. For assessment of diagnostic accuracy, patients and pulmonary vessels were reviewed binarily for affection by PE, using standard CTPA protocol datasets as the reference standard. Percentual affection of pulmonary vessels by PE was computed for disease severity (modified Qanadli score). (3) Results: Mean ED in ULD protocol was 0.7 ± 0.3 mSv (16% of standard protocol: 4.3 ± 1.7 mSv, p < 0.001, r > 0.5). Comparing ULD to standard protocol, subjective image quality and diagnostic confidence were comparably good (p = 0.486, r > 0.5) and image noise was significantly lower in ULD (p < 0.001, r > 0.5). A total of 42 patients (32.2%) were affected by PE. ULD protocol had a segment-based false-negative rate of only 0.1%. Sensitivity for detection of any PE was 98.9% (95% CI, 97.2-99.7%), specificity was 100% (95% CI, 99.8-100%), and overall accuracy was 99.9% (95% CI, 98.6-100%). Diagnoses correlated strongly between ULD and standard protocol (Chi-square (1) = 42, p < 0.001) with a decrease in disease severity of only 0.48% (T = 1.667, p = 0.103). (4) Conclusions: Compared to a standard CTPA protocol, the proposed ULD protocol proved reliable in detecting and ruling out acute PE with good levels of image quality and diagnostic confidence, as well as significantly lower image noise, at 0.7 ± 0.3 mSv (84% dose reduction).
Collapse
|
9
|
Evaluation of Organ Dose and Image Quality Metrics of Pediatric CT Chest-Abdomen-Pelvis (CAP) Examination: An Anthropomorphic Phantom Study. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11052047] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The aim of this study is to investigate the impact of CT acquisition parameter setting on organ dose and its influence on image quality metrics in pediatric phantom during CT examination. The study was performed on 64-slice multidetector CT scanner (MDCT) Siemens Definition AS (Siemens Sector Healthcare, Forchheim, Germany) using various CT CAP protocols (P1–P9). Tube potential for P1, P2, and P3 protocols were fixed at 100 kVp while P4, P5, and P6 were fixed at 80 kVp with used of various reference noise values. P7, P8, and P9 were the modification of P1 with changes on slice collimation, pitch factor, and tube current modulation (TCM), respectively. TLD-100 chips were inserted into the phantom slab number 7, 9, 10, 12, 13, and 14 to represent thyroid, lung, liver, stomach, gonads, and skin, respectively. The image quality metrics, signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were obtained from the CT console. As a result, this study indicates a potential reduction in the absorbed dose up to 20% to 50% along with reducing tube voltage, tube current, and increasing the slice collimation. There is no significant difference (p > 0.05) observed between the protocols and image metrics.
Collapse
|
10
|
McLeavy CM, Chunara MH, Gravell RJ, Rauf A, Cushnie A, Staley Talbot C, Hawkins RM. The future of CT: deep learning reconstruction. Clin Radiol 2021; 76:407-415. [PMID: 33637310 DOI: 10.1016/j.crad.2021.01.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/14/2021] [Indexed: 12/23/2022]
Abstract
There have been substantial advances in computed tomography (CT) technology since its introduction in the 1970s. More recently, these advances have focused on image reconstruction. Deep learning reconstruction (DLR) is the latest complex reconstruction algorithm to be introduced, which harnesses advances in artificial intelligence (AI) and affordable supercomputer technology to achieve the previously elusive triad of high image quality, low radiation dose, and fast reconstruction speeds. The dose reductions achieved with DLR are redefining ultra-low-dose into the realm of plain radiographs whilst maintaining image quality. This review aims to demonstrate the advantages of DLR over other reconstruction methods in terms of dose reduction and image quality in addition to being able to tailor protocols to specific clinical situations. DLR is the future of CT technology and should be considered when procuring new scanners.
Collapse
Affiliation(s)
- C M McLeavy
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - M H Chunara
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - R J Gravell
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - A Rauf
- Department of Urology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - A Cushnie
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - C Staley Talbot
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - R M Hawkins
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK.
| |
Collapse
|
11
|
The influence of iterative reconstruction level on image quality and radiation dose in CT pulmonary angiography examinations. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.108989] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
12
|
Effects of radiation dose reduction on diagnostic performance of 3rd generation Dual Source CT pulmonary angiography. Eur J Radiol 2020; 134:109426. [PMID: 33254062 DOI: 10.1016/j.ejrad.2020.109426] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/19/2020] [Accepted: 11/14/2020] [Indexed: 12/30/2022]
Abstract
PURPOSE To evaluate the effects of radiation dose reduction on diagnostic accuracy and image quality of pulmonary angiography CT (CTPA) in adults with suspected pulmonary embolism (PE). MATERIAL & METHODS 52 consecutive patients received CTPA for suspected PE. Realistic low-Dose CT simulations were generated using an offline software (ReconCT, Siemens Healthineers, Forchheim, Germany), as either filter back projections (FBP) or iterative reconstruction as ADMIRE (strength 3 or 5) with 25 %, 50 % and 75 % of the original dose. To assess image quality (overall image quality, noise, artifacts, and sharpness) and diagnostic confidence, a five-point scale was used. Patient-based and segment-based diagnostic accuracy was calculated for Low-dose computed tomography (LDCT)-reconstruction with original dose CTPA as a standard of reference. Furthermore, effective radiation doses were calculated using a commercially available dose management platform (Radimetrics, Bayer HealthCare, Leverkusen, Germany). RESULTS Among 52 patients, a total of 15 patients (28.8 %) had acute pulmonary artery embolism. The median dose-length product and effective dose for all 52 scans were 291.1 ± 210.1 mGy⋅cm and 5.8 ± 3.4 mSv. Overall subjective image quality was highest for ADMIRE 5 with 75 % and lowest for FBP with 25 % of the original dose (median [interquartile range]:5 [5] vs. 3 [2-3], p < 0.001. Patient-based diagnostic accuracy was perfect for all iteratively reconstructed data sets (ADMIRE 3 and 5) (sensitivity: 100 %, negative predictive value [NPV]: 100 %). LDCT data sets with FBP had perfect diagnostic accuracy at 50 % and 75 % of the original dose, which however decreased at 25 % of the original dose (sensitivity: 93 %; [NPV]: 97 %). Segment-based diagnostic accuracy was high for ADMIRE 3 and 5 down to 25 % dose reduction (sensitivity: 90.4 % specificity: 99.5 %) and lowest for FBP with 25 % dose reduction (sensitivity: 84.6 %, specificity: 98.9 %). Inter-class correlation regarding the detection of PE was almost perfect at all doses and recons (ICC: 96.1-1.0). Thus, accurate diagnosis for PE was possible for ADMIRE 3 and 5 datasets with 25 % of the original dose (1.45 mSv) and for FBP with 50 % of the original dose (2.9 mSv). CONCLUSION Our findings indicate that radiation dose reduction down to 25 % (1.45 mSv) of the original data via iterative reconstruction algorithms on a 3rd generation Dual Source CT (DSCT) scanner maintained the diagnostic accuracy and image quality for the assessment of PE in CTPA.
Collapse
|
13
|
Aldosari S, Sun Z. A Systematic Review of Double Low-dose CT Pulmonary Angiography in Pulmonary Embolism. Curr Med Imaging 2020; 15:453-460. [PMID: 32008552 DOI: 10.2174/1573405614666180813120619] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 07/20/2018] [Accepted: 07/31/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND The aim of this study is to perform a systematic review of the feasibility and clinical application of double low-dose CT pulmonary angiography (CTPA) in the diagnosis of patients with suspected pulmonary embolism. DISCUSSION A total of 13 studies were found to meet selection criteria reporting both low radiation dose (70 or 80 kVp versus 100 or 120 kVp) and low contrast medium dose CTPA protocols. Lowdose CTPA resulted in radiation dose reduction from 29.6% to 87.5% in 12 studies (range: 0.4 to 23.5 mSv), while in one study, radiation dose was increased in the dual-energy CT group when compared to the standard 120 kVp group. CTPA with use of low contrast medium volume (range: 20 to 75 ml) was compared to standard CTPA (range: 50 to 101 ml) in 12 studies with reduction between 25 and 67%, while in the remaining study, low iodine concentration was used with 23% dose reduction achieved. Quantitative assessment of image quality (in terms of signal-to-noise ratio and contrast-to-noise ratio) showed that low-dose CTPA was associated with higher, lower and no change in image quality in 3, 3 and 6 studies, respectively when compared to the standard CTPA protocol. The subjective assessment indicated similar image quality in 11 studies between low-dose and standard CTPA groups, and improved image quality in 1 study with low-dose CTPA. CONCLUSION This review shows that double low-dose CTPA is feasible in the diagnosis of pulmonary embolism with significant reductions in both radiation and contrast medium doses, without compromising diagnostic image quality.
Collapse
Affiliation(s)
- Sultan Aldosari
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
| | - Zhonghua Sun
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
| |
Collapse
|
14
|
Highly reduced-dose CT of the lumbar spine in a human cadaver model. PLoS One 2020; 15:e0240199. [PMID: 33031418 PMCID: PMC7544118 DOI: 10.1371/journal.pone.0240199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 09/21/2020] [Indexed: 11/25/2022] Open
Abstract
Purpose Feasibility of a highly reduced-dose lumbar spine CT protocol using iterative reconstruction (IR) in a human cadaver model. Materials and methods The lumbar spine of 20 human cadavers was repeatedly examined using three different reduced-dose protocols (RDCT) with decreasing reference tube current-exposure time products (RDCT-1: 50 mAs; RDCT-2: 30 mAs; RDCT-3: 10 mAs) at a constant tube voltage of 140 kV. A clinical standard-dose protocol (SDCT) served as the reference (reference tube current–exposure time product: 70 mAs; tube voltage: 140 kV). Images were reconstructed using filtered back projection (FBP) and two increasing levels of IR: IRL4 and IRL6. A five-point scale was used by two observers to assess the diagnostic quality of anatomical structures (cortical and trabecular bone, intervertebral foramina, pedicles and intervertebral joints, spinous and transverse processes). Objective image noise (OIN) was measured. Results were interpreted using a linear mixed-effects regression model. Results RDCT-2 with IRL6 (1.2 ± 0.5mSv) was the lowest reduced-dose protocol which provided diagnostically acceptable and equivalent image quality compared to the SDCT (2.3 ± 1.1mSV) with FBP (p > 0.05). All RDCT protocols achieved a significant reduction of the mean (±SD) effective radiation doses (RDCT-1: 1.7±0.9mSv; RDCT-2: 1.2±0.5mSv; RDCT-3: 0.4±0.2mSv; p < 0.05) compared to SDCT. OIN was lower in all RDCT protocols with the application of IRL4 and IRL6, compared to the SDCT with FBP (p < 0.05). Conclusion Highly reduced-dose lumbar spine CT providing diagnostically acceptable image quality is feasible using IR in this cadaver model and may be transferred into a clinical setting.
Collapse
|
15
|
Association of Radiation Doses and Cancer Risks from CT Pulmonary Angiography Examinations in Relation to Body Diameter. Diagnostics (Basel) 2020; 10:diagnostics10090681. [PMID: 32917029 PMCID: PMC7554806 DOI: 10.3390/diagnostics10090681] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 01/02/2023] Open
Abstract
In this study, we aimed to estimate the probability of cancer risk induced by CT pulmonary angiography (CTPA) examinations concerning effective body diameter. One hundred patients who underwent CTPA examinations were recruited as subjects from a single institution in Kuala Lumpur. Subjects were categorized based on their effective diameter size, where 19–25, 25–28, and >28 cm categorized as Groups 1, 2, and 3, respectively. The mean value of the body diameter of the subjects was 26.82 ± 3.12 cm, with no significant differences found between male and female subjects. The risk of cancer in breast, lung, and liver organs was 0.009%, 0.007%, and 0.005% respectively. The volume-weighted CT dose index (CTDIvol) was underestimated, whereas the size-specific dose estimates (SSDEs) provided a more accurate description of the radiation dose and the risk of cancer. CTPA examinations are considered safe but it is essential to implement a protocol optimized following the As Low as Reasonably Achievable (ALARA) principle.
Collapse
|
16
|
Sun Z. Use of Three-dimensional Printing in the Development of Optimal Cardiac CT Scanning Protocols. Curr Med Imaging 2020; 16:967-977. [PMID: 32107994 DOI: 10.2174/1573405616666200124124140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/22/2019] [Accepted: 11/27/2019] [Indexed: 01/01/2023]
Abstract
Three-dimensional (3D) printing is increasingly used in medical applications with most of the studies focusing on its applications in medical education and training, pre-surgical planning and simulation, and doctor-patient communication. An emerging area of utilising 3D printed models lies in the development of cardiac computed tomography (CT) protocols for visualisation and detection of cardiovascular disease. Specifically, 3D printed heart and cardiovascular models have shown potential value in the evaluation of coronary plaques and coronary stents, aortic diseases and detection of pulmonary embolism. This review article provides an overview of the clinical value of 3D printed models in these areas with regard to the development of optimal CT scanning protocols for both diagnostic evaluation of cardiovascular disease and reduction of radiation dose. The expected outcomes are to encourage further research towards this direction.
Collapse
Affiliation(s)
- Zhonghua Sun
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, 6845, Australia
| |
Collapse
|
17
|
Rajiah P, Ciancibello L, Novak R, Sposato J, Landeras L, Gilkeson R. Ultra-low dose contrast CT pulmonary angiography in oncology patients using a high-pitch helical dual-source technology. ACTA ACUST UNITED AC 2020; 25:195-203. [PMID: 31063136 DOI: 10.5152/dir.2019.17498] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
PURPOSE We aimed to determine if the image quality and vascular enhancement are preserved in computed tomography pulmonary angiography (CTPA) studies performed with ultra-low contrast and optimized radiation dose using high-pitch helical mode of a second generation dual source scanner. METHODS We retrospectively evaluated oncology patients who had CTPA on a 128-slice dual-source scanner, with a high-pitch helical mode (3.0), following injection of 30 mL of Ioversal at 4 mL/s with body mass index (BMI) dependent tube potential (80-120 kVp) and current (130-150 mAs). Attenuation, noise, and signal-to-noise ratio (SNR) were measured in multiple pulmonary arteries. Three independent readers graded the images on a 5-point Likert scale for central vascular enhancement (CVE), peripheral vascular enhancement (PVE), and overall quality. RESULTS There were 50 males and 101 females in our study. BMI ranged from 13 to 38 kg/m2 (22.8±4.4 kg/m2). Pulmonary embolism was present in 29 patients (18.9%). Contrast enhancement and SNR were excellent in all the pulmonary arteries (395.3±131.1 and 18.3±5.7, respectively). Image quality was considered excellent by all the readers, with average reader scores near the highest possible score of 5.0 (CVE, 4.83±0.48; PVE, 4.68±0.65; noise/quality, 4.78±0.47). The average radiation dose length product (DLP) was 161±60 mGy.cm. CONCLUSION Using a helical high-pitch acquisition technique, CTPA images of excellent diagnostic quality, including visualization of peripheral segmental/sub-segmental branches can be obtained using an ultra-low dose of iodinated contrast and low radiation dose.
Collapse
Affiliation(s)
- Prabhakar Rajiah
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA;Department of Radiology, Cardiothoracic Imaging, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Leslie Ciancibello
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| | - Ronald Novak
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA;Rebecca D. Considine Research Institute, Akron Children's Hospital, Akron, Ohio, USA
| | - Jennifer Sposato
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| | - Luis Landeras
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA;Department of Radiology, University of Chicago, Chicago, Illinois, USA
| | - Robert Gilkeson
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| |
Collapse
|
18
|
Harun HH, Karim MKA, Abbas Z, Sabarudin A, Muniandy SC, Ibahim MJ. Effect of iterative reconstruction algorithm levels on noise index and figure-of-merit in CT pulmonary angiography examinations. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2020; 28:893-903. [PMID: 32741801 DOI: 10.3233/xst-200699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
PURPOSE To evaluate the influence of iterative reconstruction (IR) levels on Computed Tomography (CT) image quality and to establish Figure of Merit (FOM) value for CT Pulmonary Angiography (CTPA) examinations. METHODS Images of 31 adult patients who underwent CTPA examinations in our institution from March to April 2019 were retrospectively collected. Other data, such as scanning parameters, radiation dose and body habitus information from the subjects were also recorded. Six different levels of IR were applied to the volume data of the subjects. Five circles of the region of interest (ROI) were drawn in five different arteries namely, pulmonary trunk, right pulmonary artery, left pulmonary artery, ascending aorta and descending aorta. The mean Signal-to-noise ratio (SNR) was obtained, and the FOM was calculated in a fraction of the SNR2 divided by volume-weighted CT dose index (CTDIvol) and SNR2 divided by the size-specific dose estimates (SSDE). RESULTS Overall, we observed that the mean value of CTDIvol and SSDE were 13.79±7.72 mGy and 17.25±8.92 mGy, respectively. Notably, SNR values significantly increase with increase of the IR level (p < 0.05). There are also significant differences (p < 0.05) in the FOM for both SNR2/SSDE and SNR2/CTDIvol attained in different IR levels. CONCLUSION We successfully evaluate the value of radiation dose and image quality performance and set up a figure of merit for both parameters to further verify scanning protocols by radiology personnel.
Collapse
Affiliation(s)
- H H Harun
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - M K A Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Z Abbas
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - A Sabarudin
- Department of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysiainstitution>
| | - S C Muniandy
- Department of Radiology, Hospital Kuala Lumpur, Jalan Pahang, Kuala Lumpur, Malaysia
| | - M J Ibahim
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh, Selangor, Malaysia
| |
Collapse
|
19
|
Karim MKA, Sabarudin A, Muhammad NA, Ng KH. A comparative study of radiation doses between phantom and patients via CT angiography of the intra-/extra-cranial, pulmonary, and abdominal/pelvic arteries. Radiol Phys Technol 2019; 12:374-381. [PMID: 31468370 DOI: 10.1007/s12194-019-00532-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 10/26/2022]
Abstract
This study aimed to evaluate effective dose and size-specific dose estimate (SSDE) of computed tomography angiography (CTA) examination using an anthropomorphic phantom. We included three CTA examination protocols to evaluate the intra- and extra-cranial arteries, pulmonary artery (CTPA), and abdominal vessels. Patient SSDEs were measured retrospectively to estimate patient dose, relative to the bodyweight of the patient and volume CT dose index (CTDIvol). Our findings revealed that the highest dose was absorbed by the left lobe of the thyroid gland during intra-/extra-cranial CTA and CTPA, that is, 14.11 ± 0.24 mGy and 16.20 ± 3.95 mGy, respectively. However, the highest absorbed dose in abdominal/pelvic CTA was the gonads (8.98 ± 0.30 mGy), while other radiosensitive organs in intra- and extra-cranial CTA, CTPA, and abdominal/pelvic CTA did not demonstrate significant differences between organs/structures with p value 0.88, 0.11, and 0.54, respectively. The estimated effective dose in intra-/extra-cranial CTA was lower in patients (0.80 ± 0.60 mSv) than in the phantom (0.83 mSv), but it was the opposite for CTPA, with the effective dose being higher in patients (7.54 ± 3.09 mSv) than in the phantom (6.68 mSv). Similar to the effective dose, only CTPA SSDEs were significantly higher in men than in women (19.74 ± 4.79 mGy versus 7.9 mGy). Effective dose and SSDE are clinically relevant parameters that can help estimate a more accurate patient dose based on a patient's size.
Collapse
Affiliation(s)
- M K A Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - A Sabarudin
- Programme of Diagnostic Imaging and Radiotherapy, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 56000, Kuala Lumpur, Malaysia
| | - N A Muhammad
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - K H Ng
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| |
Collapse
|
20
|
Aldosari S, Jansen S, Sun Z. Patient-specific 3D printed pulmonary artery model with simulation of peripheral pulmonary embolism for developing optimal computed tomography pulmonary angiography protocols. Quant Imaging Med Surg 2019; 9:75-85. [PMID: 30788248 PMCID: PMC6351806 DOI: 10.21037/qims.2018.10.13] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 10/26/2018] [Indexed: 11/06/2022]
Abstract
BACKGROUND Computed tomography pulmonary angiography (CTPA) is the preferred imaging modality for diagnosis of patients with suspected pulmonary embolism (PE). Radiation dose associated with CTPA has been significantly reduced due to the use of dose-reduction strategies, however, investigation of low-dose CTPA with use of different kVp and pitch values has not been systematically studied. The aim of this study was to utilize a 3D printed pulmonary model with simulation of small thrombus in the pulmonary arteries for development of optimal CTPA protocols. METHODS Animal blood clots were inserted into the pulmonary arteries to simulate peripheral embolism based on a realistic 3D printed pulmonary artery model. The 3D printed model was scanned with 192-slice 3rd generation dual-source CT with 1 mm slice thickness and 0.5 mm reconstruction interval. All images were reconstructed with advanced modelled iterative reconstruction (IR) at a strength level of 3. CTPA scanning parameters were as follows: 70, 80, 100 and 120 kVp, 0.9, 2.2 and 3.2 pitch values. Quantitative assessment of image quality was determined by measuring signal-to-noise ratio (SNR) in both main pulmonary arteries, while qualitative analysis of images was scored by two experienced radiologists (score of 1 indicates poor visualization of thrombus with no confidence, and score of 5 excellent visualization of thrombus with high confidence) to determine the image quality in relation to different scanning protocols for detection of thrombus in the pulmonary arteries. RESULTS No significant differences were found in SNR measurements among all CTPA protocols (P>0.05), regardless of kVp or pitch values used, although SNR was higher with 120 kVp and 0.9 and 2.2 pitch protocols than that in other protocols. The thrombi were detected in all images, with 70 kVp and 3.2 pitch protocol scored the lowest with a score of 3 by two observers, and images with other protocols were scored 4 or 5. Lowering kVp from 120 to 70 with use of high-pitch 2.2 or 3.2 protocol resulted in up to 80% dose reduction without significantly affecting image quality. CONCLUSIONS Low-dose CT pulmonary angiography protocols comprising 70 kVp and high pitch 2.2 or 3.2 allow for detection of peripheral PE with significant reduction in radiation dose while images are still considered diagnostic.
Collapse
Affiliation(s)
- Sultan Aldosari
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
| | - Shirley Jansen
- Department of Vascular and Endovascular Surgery, Sir Charles Gairdner Hospital, Perth, Australia
- Curtin Medical School, Curtin University, Perth, Australia
- Faculty of Health and Medical Sciences, University of Western Australia, Crawley, Australia
- Heart and Vascular Research Institute, Harry Perkins Medical Research Institute, Perth, Australia
| | - Zhonghua Sun
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
| |
Collapse
|
21
|
Aldosari S, Jansen S, Sun Z. Optimization of computed tomography pulmonary angiography protocols using 3D printed model with simulation of pulmonary embolism. Quant Imaging Med Surg 2019; 9:53-62. [PMID: 30788246 DOI: 10.21037/qims.2018.09.15] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Three-dimensional (3D) printing has been shown to accurately replicate anatomical structures and pathologies in complex cardiovascular disease. Application of 3D printed models to simulate pulmonary arteries and pulmonary embolism (PE) could assist development of computed tomography pulmonary angiography (CTPA) protocols with low radiation dose, however, this has not been studied in the literature. The aim of this study was to investigate optimal CTPA protocols for detection of PE based on a 3D printed pulmonary model. Methods A patient-specific 3D printed pulmonary artery model was generated with thrombus placed in both main pulmonary arteries to represent PE. The model was scanned with 128-slice dual-source CT with slice thickness of 1 and 0.5 mm reconstruction interval. The tube voltage was selected to range from 70, 80, 100 to 120 kVp, and pitch value from 0.9 to 2.2 and 3.2. Quantitative assessment of image quality in terms of signal-to-noise ratio (SNR) was measured in the main pulmonary arteries and within the thrombus regions to determine the relationship between image quality and scanning protocols. Both two-dimensional (2D) and 3D virtual intravascular endoscopy (VIE) images were generated to demonstrate pulmonary artery and thrombus appearances. Results PE was successfully simulated in the 3D printed pulmonary artery model. There were no significant differences in SNR measured in the main pulmonary arteries with 100 and 120 kVp CTPA protocols (P>0.05), regardless of pitch value used. SNR was significantly lower in the high-pitch 3.2 protocols when compared to other protocols using 70 and 80 kVp (P<0.05). There were no significant differences in SNR measured within the thrombus among the 100 and 120 kVp protocols (P>0.05). For low dose 70 and 80 kVp protocols, SNR was significantly lower in the high-pitch of 3.2 protocols than that in other protocols with different pitch values (P<0.01). 2D images showed the pulmonary arteries and thrombus clearly, while 3D VIE demonstrated intraluminal appearances of pulmonary wall and thrombus in all protocols, except for the 70 kVp and pitch 3.2 protocol, with visualization of thrombus and pulmonary artery wall affected by artifact associated with high image noise. Radiation dose was reduced by up to 80% when lowering kVp from 120 to 100 and 80 kVp with use of 3.2 high-pitch protocol, without significantly affecting image quality. Conclusions Low-dose CT pulmonary angiography can be achieved with use of low kVp (80 and 100) and high-pitch protocol with significant reduction in radiation dose while maintaining diagnostic images of PE. Use of high pitch, 3.2 in 70 kVp protocol should be avoided due to high image noise and poorer quality.
Collapse
Affiliation(s)
- Sultan Aldosari
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
| | - Shirley Jansen
- Department of Vascular and Endovascular Surgery, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,School of Public Health, Curtin University, Perth, Western Australia, Australia.,Faculty of Health and Medical Sciences, University of Western Australia, Crawley, Western Australia, Australia.,Heart and Vascular Research Institute, Harry Perkins Medical Research Institute, Perth, Western Australia, Australia
| | - Zhonghua Sun
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
| |
Collapse
|
22
|
Improved Delineation of Pulmonary Embolism and Venous Thrombosis Through Frequency Selective Nonlinear Blending in Computed Tomography. Invest Radiol 2017; 52:240-244. [PMID: 27861205 DOI: 10.1097/rli.0000000000000333] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of this study was to test the hypothesis that a novel frequency selective nonlinear blending (NLB) algorithm increases the delineation of pulmonary embolism and venous thrombosis in portal-venous phase whole-body staging computed tomography (CT). MATERIALS AND METHODS A cohort of 67 patients with incidental pulmonary embolism and/or venous thrombosis in contrast-enhanced oncological staging CT were retrospectively selected. Computed tomography data sets were acquired 65 to 90 seconds after intravenous iodine contrast administration using state-of-the-art multi-detector CT scanners. A novel frequency selective NLB postprocessing technique was applied to reconstructed standard CT images. Two readers determined the most suitable settings to increase the delineation of pulmonary embolism and venous thrombosis. Outcome measure included region of interest and contrast-to-noise ratio (CNR) analyses, image noise, overall image quality, subjective delineation, as well as number and size of emboli and thrombi. Statistical testing included quantitative comparisons of Hounsfield units of thrombus and vessel, image noise and related CNR values and subjective image analyses of image noise, image quality and thrombus delineation, number and size in standard, and NLB images. RESULTS Using frequency selective NLB settings with a center of 100 HU, delta of 40 HU, and a slope of 5, CNR values of pulmonary embolism (StandardCNR, 10 [6, 16]; NLBCNR, 22 [15, 30]; P < 0.001) and venous thrombosis (StandardCNR, 8 [5, 15]; NLBCNR, 12 [7, 19]; P = 0.0007) increased. Mean vascular enhancement using NLB was significantly higher than in standard images for pulmonary arteries (Standard, 138 [118, 191] HU; NLB, 269 [176, 329] HU; P < 0.0001) and veins (Standard, 120 [103, 162] HU; NLB, 169 [132, 217] HU; P < 0.0001), respectively. Image noise was not significantly different between standard and NLB images (P = 0.64-0.88). There was substantial to almost perfect interrater agreement as well as a significant increase of overall image quality (P < 0.004) and subjective delineation of the thrombotic material (P < 0.0001) in both subgroups. Nonlinear blending images revealed 8 additional segmental and 13 subsegmental emboli. Thrombus sizes were not significantly different, but subjective accuracy of the measurement could be significantly increased using NLB (P = 0.03). CONCLUSIONS Postprocessing of standard whole-body staging CT images with frequency selective NLB improves image quality and the delineation of pulmonary embolism and venous thrombosis.
Collapse
|
23
|
Image Quality of a Novel Frequency Selective Nonlinear Blending Algorithm: An Ex Vivo Phantom Study in Comparison to Single-Energy Acquisitions and Dual-Energy Acquisitions With Monoenergetic Reconstructions. Invest Radiol 2017; 51:647-54. [PMID: 27175549 DOI: 10.1097/rli.0000000000000293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Aim of this ex vivo phantom study was to evaluate the contrast enhancement applying a new frequency split nonlinear blending algorithm (best contrast [BC]) and to compare it with standard 120-kV single-energy computed tomography (SECT) images, as well as with low-kiloelectron volt monoenergetic extrapolations (Mono+40-100keV) from dual-energy CT (DECT) and with low-kilovolt (70-100 kV) SECT acquisitions. MATERIALS AND METHODS A dilution series of iodinated contrast material-filled syringes was centered in an attenuation phantom and was scanned with SECT70-120kV and DECT80-100/Sn150. Monoenergetic images (40-100 keV) were reconstructed, and a new manual frequency split nonlinear blending algorithm (BC) was applied to SECT70kV and SECT120kV images. Manual BC settings were set to simulate a reading situation with fixed overall best values (FVBC120kV) as well as to achieve best possible values for each syringe (BVBC120kV) for maximum contrast enhancement. Contrast-to-noise ratios (CNRs) were used as an objective region of interest-based image analysis parameter. Two radiologists evaluated the detectability of hyperdense and hypodense syringes (Likert). Results were compared between SECT70-100kV, Mono+40-100keV, and DECT80-100/Sn150kV, as well as FVBC120kV, BVBC120kV, and BC70kV. RESULTS Highest CNR without BC was detected at SECT70kV (5.04 ± 0.12) and Mono+40keV (4.40 ± 0.11). FVBC and BVBC images allow a significant increase of CNR compared with SECT120kV (CNRBVBC, 5.21 ± 0.15; CNRFVBC, 5.12 ± 0.16; CNRSECT120kV, 2.5 ± 0.08; all P ≤ 0.01). There was no significant difference in CNR between BVBC and FVBC. Averaged CNR in BVBC and FVBC was significantly higher compared with Mono+40-100keV (all P ≤ 0.01). Compared with SECT70kV, averaged CNR in BVBC and FVBC show no significant differences. BVBC70kV (7.67 ± 0.17) significantly increases CNR in SECT70kV up to 213%.Subjective image analysis showed an interobserver agreement of 0.63 to 0.83 (κ), confirming the superiority of BC in detecting hyperdense and hypodense syringes, when compared with SECT120kV. Compared with SECT120kV, BVBC70kV was scored highest, followed by SECT70kV. BVBC showed higher scores when comparing to Mono+40keV, however almost identical to those of SECT70kV. Scores of FVBC were slightly lower than SECT70kV, but in the range of Mono+40keV. CONCLUSIONS The new frequency split nonlinear blending algorithm with fixed settings offers a superior differentiation of contrast levels from low- to high-contrast settings. Using the optimal settings, this algorithm shows an equivalent contrast enhancement when compared with SECT70kV. Because of the non-DECT-based algorithm of BC, the new method of contrast enhancement seems to be particularly valuable for implementation in CT systems not equipped for dual-energy or spectral CT imaging.
Collapse
|
24
|
Radiation dose-reduction strategies in thoracic CT. Clin Radiol 2017; 72:407-420. [DOI: 10.1016/j.crad.2016.11.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/31/2016] [Accepted: 11/14/2016] [Indexed: 01/08/2023]
|
25
|
Kaup M, Gruber-Rouh T, Scholtz JE, Albrecht MH, Bucher A, Frellesen C, Vogl TJ, Beeres M. Low-dose CT pulmonary angiography on a 15-year-old CT scanner: a feasibility study. Acta Radiol Open 2017; 5:2058460116684371. [PMID: 28286671 PMCID: PMC5330415 DOI: 10.1177/2058460116684371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 11/22/2016] [Indexed: 11/16/2022] Open
Abstract
Background Computed tomography (CT) low-dose (LD) imaging is used to lower radiation exposure, especially in vascular imaging; in current literature, this is mostly on latest generation high-end CT systems. Purpose To evaluate the effects of reduced tube current on objective and subjective image quality of a 15-year-old 16-slice CT system for pulmonary angiography (CTPA). Material and Methods CTPA scans from 60 prospectively randomized patients (28 men, 32 women) were examined in this study on a 15-year-old 16-slice CT scanner system. Standard CT (SD) settings were 100 kV and 150 mAs, LD settings were 100 kV and 50 mAs. Attenuation of the pulmonary trunk, various anatomic landmarks, and image noise were quantitatively measured; contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) were calculated. Three independent blinded radiologists subjectively rated each image series using a 5-point grading scale. Results CT dose index (CTDI) in the LD series was 66.46% lower compared to the SD settings (2.49 ± 0.55 mGy versus 7.42 ± 1.17 mGy). Attenuation of the pulmonary trunk showed similar results for both series (SD 409.55 ± 91.04 HU; LD 380.43 HU ± 93.11 HU; P = 0.768). Subjective image analysis showed no significant differences between SD and LD settings regarding the suitability for detection of central and peripheral PE (central SD/LD, 4.88; intra-class correlation coefficients [ICC], 0.894/4.83; ICC, 0.745; peripheral SD/LD, 4.70; ICC, 0.943/4.57; ICC, 0.919; all P > 0.4). Conclusion The LD protocol, on a 15-year-old CT scanner system without current high-end hardware or post-processing tools, led to a dose reduction of approximately 67% with similar subjective image quality and delineation of central and peripheral pulmonary arteries.
Collapse
Affiliation(s)
- Moritz Kaup
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Tatjana Gruber-Rouh
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Jan E Scholtz
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Moritz H Albrecht
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Andreas Bucher
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Claudia Frellesen
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Thomas J Vogl
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Martin Beeres
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| |
Collapse
|
26
|
Tilve-Gómez A, Rodríguez-Fernández P, Trillo-Fandiño L, Plasencia-Martínez JM. Imaging techniques used in the diagnostic workup of acute venous thromboembolic disease. RADIOLOGIA 2016; 59:329-342. [PMID: 27986265 DOI: 10.1016/j.rx.2016.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 09/09/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
Abstract
Early diagnosis is one of the most important factors affecting the prognosis of pulmonary embolism (PE); however, the clinical presentation of PE is often very unspecific and it can simulate other diseases. For these reasons, imaging tests, especially computed tomography angiography (CTA) of the pulmonary arteries, have become the keystone in the diagnostic workup of PE. The wide availability and high diagnostic performance of pulmonary CTA has led to an increase in the number of examinations done and a consequent increase in the population's exposure to radiation and iodinated contrast material. Thus, other techniques such as scintigraphy and venous ultrasonography of the lower limbs, although less accurate, continue to be used in certain circumstances, and optimized protocols have been developed for CTA to reduce the dose of radiation (by decreasing the kilovoltage) and the dose of contrast agents. We describe the technical characteristics and interpretation of the findings for each imaging technique used to diagnose PE and discuss their advantages and limitations; this knowledge will help the best technique to be chosen for each case. Finally, we comment on some data about the increased use of CTA, its clinical repercussions, its "overuse", and doubts about its cost-effectiveness.
Collapse
Affiliation(s)
- A Tilve-Gómez
- Servicio de Radiodiagnóstico, IISGS, XXIV, Hospital Álvaro Cunqueiro, Vigo (Pontevedra), España.
| | - P Rodríguez-Fernández
- Servicio de Radiodiagnóstico, IISGS, XXIV, Hospital Álvaro Cunqueiro, Vigo (Pontevedra), España
| | - L Trillo-Fandiño
- Servicio de Radiodiagnóstico, IISGS, XXIV, Hospital Álvaro Cunqueiro, Vigo (Pontevedra), España
| | - J M Plasencia-Martínez
- Servicio de Radiodiagnóstico, Hospital General Universitario José María Morales Meseguer, Murcia, España
| |
Collapse
|
27
|
Laqmani A, Kurfürst M, Butscheidt S, Sehner S, Schmidt-Holtz J, Behzadi C, Nagel HD, Adam G, Regier M. CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP. PLoS One 2016; 11:e0162429. [PMID: 27611448 PMCID: PMC5017776 DOI: 10.1371/journal.pone.0162429] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/28/2016] [Indexed: 12/01/2022] Open
Abstract
Purpose To assess image quality of CT pulmonary angiography (CTPA) at reduced radiation exposure (RD-CTPA) and contrast medium (CM) volume using two different iterative reconstruction (IR) algorithms (iDose4 and iterative model reconstruction (IMR)) in comparison to filtered back projection (FBP). Materials and Methods 52 patients (body weight < 100 kg, mean BMI: 23.9) with suspected pulmonary embolism (PE) underwent RD-CTPA (tube voltage: 80 kV; mean CTDIvol: 1.9 mGy) using 40 ml CM. Data were reconstructed using FBP and two different IR algorithms (iDose4 and IMR). Subjective and objective image quality and conspicuity of PE were assessed in central, segmental, and subsegmental arteries. Results Noise reduction of 55% was achieved with iDose4 and of 85% with IMR compared to FBP. Contrast-to-noise ratio significantly increased with iDose4 and IMR compared to FBP (p<0.05). Subjective image quality was rated significantly higher at IMR reconstructions in comparison to iDose4 and FBP. Conspicuity of central and segmental PE significantly improved with the use of IMR. In subsegmental arteries, iDose4 was superior to IMR. Conclusions CTPA at reduced radiation exposure and contrast medium volume is feasible with the use of IMR, which provides improved image quality and conspicuity of pulmonary embolism in central and segmental arteries.
Collapse
Affiliation(s)
- Azien Laqmani
- Department for Interventional and Diagnostic Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
| | - Maximillian Kurfürst
- Department for Interventional and Diagnostic Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sebastian Butscheidt
- Department for Interventional and Diagnostic Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Sehner
- Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jakob Schmidt-Holtz
- Department for Interventional and Diagnostic Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Cyrus Behzadi
- Department for Interventional and Diagnostic Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Gerhard Adam
- Department for Interventional and Diagnostic Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marc Regier
- Department for Interventional and Diagnostic Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
28
|
Improved CT Detection of Acute Herpes Simplex Virus Type 1 Encephalitis Based on a Frequency-Selective Nonlinear Blending: Comparison With MRI. AJR Am J Roentgenol 2016; 207:1082-1088. [PMID: 27533625 DOI: 10.2214/ajr.16.16032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study is to compare the diagnostic efficacy of a new CT postprocessing tool based on frequency-selective nonlinear blending (best-contrast CT) with that of standard linear blending of unenhanced head CT in patients with herpes simplex virus type 1 and herpes simplex virus encephalitis (HSE), using FLAIR MRI sequences as the standard of reference. MATERIALS AND METHODS Fifteen consecutive patients (six women and nine men; mean [± SD] age, 60 ± 19 years) with proven HSE (positive polymerase chain reaction results from CSF analysis and the presence of neurologic deficits) were retrospectively enrolled. All patients had undergone head CT and MRI (mean time interval, 2 ± 2 days). After standardized unenhanced head CT scans were read, presets of the best-contrast algorithm were determined (center, 30 HU; delta, 5 HU; slope, 5 nondimensional), and resulting images were analyzed. Contrast enhancement was objectively measured by ROI analysis, comparing contrast-to-noise ratios (CNRs) of unenhanced CT and best-contrast CT. FLAIR and DWI MRI sequences were analyzed, and FLAIR was considered as the standard of reference. For assessment of disease extent, a previously reported 50-point score (HSE score) was used. RESULTS CNR values for unenhanced head CT (CNR, 5.42 ± 2.77) could be statistically significantly increased using best-contrast CT (CNR, 9.62 ± 4.28) (p = 0.003). FLAIR sequences yielded a median HSE score of 9.0 (range, 6-17) and DWI sequences yielded HSE scores of 6.0 (range, 5-17). By comparison, unenhanced head CT resulted in a median HSE score of 3.5 (range, 1-6). The median best-contrast CT HSE score was 7.5 (range, 6-10). Agreement between FLAIR and unenhanced CT was 54.44%, that between DWI and best-contrast CT was 95.36%, and that between FLAIR and best-contrast CT was 85.21%. The most frequently overseen findings were located at the level of the upper part of the mesencephalon and at the subthalamic or insular level. CONCLUSION Frequency-selective nonlinear blending significantly increases contrast and detects brain parenchymal involvement in HSE more sensitively compared with unenhanced CT. The sensitivity of best-contrast CT seems to be equal to that of DWI and almost as good as that of FLAIR.
Collapse
|
29
|
Boos J, Kröpil P, Lanzman RS, Aissa J, Schleich C, Heusch P, Sawicki LM, Antoch G, Thomas C. CT pulmonary angiography: simultaneous low-pitch dual-source acquisition mode with 70 kVp and 40 ml of contrast medium and comparison with high-pitch spiral dual-source acquisition with automated tube potential selection. Br J Radiol 2016; 89:20151059. [PMID: 27007972 DOI: 10.1259/bjr.20151059] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To assess the feasibility of a 70-kVp CT pulmonary angiography (CTPA) protocol using simultaneous dual-source (SimDS) acquisition mode with 40 ml of contrast medium (CM) and comparison with a high-pitch spiral dual-source (SpiralDS) acquisition protocol with automated tube potential selection (ATPS). METHODS Following the introduction of a new 70-kVp/40-ml SimDS-CTPA protocol in December 2014 for all patients with a body mass index (BMI) below 35 kg m(-2), the first 35 patients were retrospectively included in this study and assigned to Group A (BMI: 27 ± 4 kg m(-2), age: 66 ± 15 years). The last 35 patients with a BMI below 35 kg m(-2) who had received SpiralDS-CTPA with ATPS were included for comparison (Group B) (70 ml CM; BMI: 27 ± 4 kg m(-2), age: 68 ± 16 years). Subjective image quality (image quality) was assessed by two radiologists (from 1, non-diagnostic, to 4, excellent). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), volumetric CT dose index (CTDIvol), dose-length product (DLP) and effective dose were assessed. RESULTS All examinations were of diagnostic image quality. Subjective image quality, SNR and CNR were comparable between Groups A and B (3.7 ± 0.6 vs 3.7 ± 0.5, 14.6 ± 6.0 vs 13.9 ± 3.7 and 12.4 ± 5.7 vs 11.6 ± 3.3, respectively; p > 0.05). CTDIvol, DLP and effective dose were significantly lower in Group A than in Group B (4.5 ± 1.6 vs 7.5 ± 2.1 mGy, 143.3 ± 44.8 vs 278.3 ± 79.44 mGy cm and 2.0 ± 0.6 vs 3.9 ± 1.1 mSv, respectively; p < 0.05). CONCLUSION 70-kVp SimDS-CTPA with 40 ml of CM is feasible and provides diagnostic image quality, while radiation dose and CM can be reduced by almost 50% and 40%, respectively, compared with a SpiralDS-CTPA protocol with ATPS. ADVANCES IN KNOWLEDGE 70-kVp SimDS-CTPA with 40 ml of CM is feasible in patients with a BMI up to 35 kg m(-2) and can help reduce radiation exposure and CM in these patients.
Collapse
Affiliation(s)
- Johannes Boos
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Patric Kröpil
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Rotem S Lanzman
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Joel Aissa
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Christoph Schleich
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Philipp Heusch
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Lino M Sawicki
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Gerald Antoch
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| | - Christoph Thomas
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Dusseldorf, Germany
| |
Collapse
|
30
|
Enhanced gray-white matter differentiation on non-enhanced CT using a frequency selective non-linear blending. Neuroradiology 2016; 58:649-55. [DOI: 10.1007/s00234-016-1674-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 03/03/2016] [Indexed: 11/25/2022]
|
31
|
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]
|
32
|
Hendriks BMF, Kok M, Mihl C, Bekkers SCAM, Wildberger JE, Das M. Individually tailored contrast enhancement in CT pulmonary angiography. Br J Radiol 2016; 89:20150850. [PMID: 26689096 DOI: 10.1259/bjr.20150850] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The purpose was to evaluate individually shaped contrast media (CM) delivery in CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE). METHODS 100 consecutive emergency patients with clinical suspicion of PE were evaluated. High-pitch CTPA was performed on a second-generation dual-source CT using the following parameters: 100 kV, 200-250 mAsref, rotation time 0.28 s, 128 × 0.6 mm col. and image reconstruction 1.0/0.8 mm (B30f). Group 1 (n = 50) then received a fixed CM bolus (300 = mgI ml(-1), volume = 90 ml and flow rate = 6 ml s(-1)); Group 2 (n = 50) received a body weight-adapted CM bolus determined by dedicated contrast injection software. For analysis, groups were further subdivided into low-weight (40-75 kg) and high-weight (76-117 kg) groups. Technical image quality was graded using a four-point Likert scale (1 = non-diagnostic; 2 = diagnostic; 3 = good and 4 = excellent image quality) at the level of the pulmonary trunk and pulmonary arteries. Objective image quality analysis was performed by measuring contrast enhancement in Hounsfield units (HU) at the same levels. Attenuation levels > 180 HU were considered diagnostic. RESULTS All examinations were graded as diagnostic at each level. The individual minimum pulmonary attenuation was 184 and 270 HU for Group 1 and 2, respectively. Mean attenuation was as follows: Group 1: 475 ± 105 HU (40-75 kg) and 402 ± 115 HU (76-117 kg), p < 0.03. Group 2: 424 ± 76 HU (40-75 kg) and 418 ± 100 HU (76-117 kg), p = 0.8. For Group 2, CM volumes were: 55 ± 5 ml (40-75 kg) and 66 ± 5 ml (76-117 kg), leading to 16-51% CM reduction. CONCLUSION Even under emergency conditions, individualized CM protocols can provide diagnostic and robust image quality in CTPA for PE with a substantial reduction of CM volume for lower weight patients, compared with a fixed CM protocol. ADVANCES IN KNOWLEDGE CM volume can substantially be reduced by using individualized CM protocols in CT angiography for PE without compromising the diagnostic image quality.
Collapse
Affiliation(s)
- Babs M F Hendriks
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Madeleine Kok
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Casper Mihl
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Sebastiaan C A M Bekkers
- 2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands.,3 Departments of Cardiology, Maastricht University Medical Center, Maastricht, Netherlands
| | - Joachim E Wildberger
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Marco Das
- 1 Departments of Radiology, Maastricht University Medical Center, Maastricht, Netherlands.,2 CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| |
Collapse
|
33
|
70-kVp High-pitch Computed Tomography Pulmonary Angiography with 40 mL Contrast Agent: Initial Experience. Acad Radiol 2015; 22:1562-70. [PMID: 26432073 DOI: 10.1016/j.acra.2015.08.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/25/2015] [Accepted: 08/23/2015] [Indexed: 12/11/2022]
Abstract
RATIONALE AND OBJECTIVES To assess image quality, radiation dose, and diagnostic accuracy of 70-kVp high-pitch computed tomography pulmonary angiography (CTPA) using 40 mL contrast agent and sinogram affirmed iterative reconstruction (SAFIRE) compared to 100-kVp CTPA using 60 mL contrast agent and filtered back projection. MATERIALS AND METHODS Eighty patients underwent CTPA at either 70 kVp (group A, n = 40; 3.2 pitch, 40 mL contrast medium, and SAFIRE) or 100 kVp (group B, n = 40; 1.2 pitch, 60 mL contrast medium, and filtered back projection). Signal-to-noise ratio and contrast-to-noise ratio were calculated. Subjective image quality was evaluated using a five-grade scale, and diagnostic accuracy was assessed. Radiation doses were compared. RESULTS Computed tomography values, signal-to-noise ratio, and contrast-to-noise ratio of pulmonary arteries were higher in group A compared to group B (all P < 0.001). Subjective image quality showed no difference between the two groups (P = 0.559) with good interobserver agreement (κ = 0.647). No difference was found regarding diagnostic accuracy between the two groups (P > 0.05). The effective dose for group A was lower by 80% compared to group B (P < 0.001). CONCLUSIONS 70-kVp high-pitch CTPA with reduced contrast media and SAFIRE provides comparable image quality and substantial radiation dose savings compared to a routine CTPA protocol.
Collapse
|
34
|
Laqmani A, Veldhoen S, Dulz S, Derlin T, Behzadi C, Schmidt-Holtz J, Wassenberg F, Sehner S, Nagel HD, Adam G, Regier M. Reduced-dose abdominopelvic CT using hybrid iterative reconstruction in suspected left-sided colonic diverticulitis. Eur Radiol 2015; 26:216-24. [PMID: 26070499 DOI: 10.1007/s00330-015-3810-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 04/13/2015] [Accepted: 04/20/2015] [Indexed: 01/25/2023]
Abstract
OBJECTIVES To assess the effect of hybrid iterative reconstruction (HIR) and filtered back projection (FBP) on abdominopelvic CT with reduced-dose (RD-APCT) in the evaluation of acute left-sided colonic diverticulitis (ALCD). METHODS Twenty-five consecutive patients with suspected ALCD who underwent RD-APCT (mean CTDIvol 11.2 ± 4.2 mGy) were enrolled in this study. Raw data were reconstructed using FBP and two increasing HIR levels, L4 & L6. Two radiologists assessed image quality, image noise and reviewer confidence in interpreting findings of ALCD, including wall thickening, pericolic fat inflammation, pericolic abscess, and contained or free extraluminal air. Objective image noise (OIN) was measured. RESULTS OIN was reduced up to 54 % with HIR compared to FBP. Subjective image quality of HIR images was superior to FBP; subjective image noise was reduced. The detection rate of extraluminal air was higher with HIR L6. Reviewer confidence in interpreting CT findings of ALCD significantly improved with application of HIR. CONCLUSIONS RD-APCT with HIR offers superior image quality and lower image noise compared to FBP, allowing a high level of reviewer confidence in interpreting CT findings in ALCD. HIR facilitates detection of ALCD findings that may be missed with the FBP algorithm. KEY POINTS HIR significantly reduces objective image noise in comparison to conventional FBP. HIR offers superior subjective image quality in comparison to conventional FBP. HIR allows reduced-dose abdominopelvic CT with acceptable image quality. Reviewer confidence in interpreting CT findings in ALCD significantly improves with HIR.
Collapse
Affiliation(s)
- Azien Laqmani
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany.
| | - Simon Veldhoen
- Department of Diagnostic and Interventional Radiology, University Medical Center Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Simon Dulz
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Thorsten Derlin
- Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Cyrus Behzadi
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Jakob Schmidt-Holtz
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Felicia Wassenberg
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Susanne Sehner
- Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Hans-Dieter Nagel
- Scientific and Application-oriented Studies and Consulting in Radiology (SASCRAD), Fritz-Reuter-Weg 5f, 21244, Buchholz, Germany
| | - Gerhard Adam
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Marc Regier
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| |
Collapse
|
35
|
Clarke R, Lewis EF. Feasibility of Using Iterative Reconstruction to Reduce Radiation Dose for Computed Tomography Pulmonary Angiograms. J Med Imaging Radiat Sci 2015; 46:50-56. [DOI: 10.1016/j.jmir.2014.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 10/24/2022]
|