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Bal SS, Yang FPG, Chi NF, Yin JH, Wang TJ, Peng GS, Chen K, Hsu CC, Chen CI. Core and penumbra estimation using deep learning-based AIF in association with clinical measures in computed tomography perfusion (CTP). Insights Imaging 2023; 14:161. [PMID: 37775600 PMCID: PMC10541385 DOI: 10.1186/s13244-023-01472-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/23/2023] [Indexed: 10/01/2023] Open
Abstract
OBJECTIVES To investigate whether utilizing a convolutional neural network (CNN)-based arterial input function (AIF) improves the volumetric estimation of core and penumbra in association with clinical measures in stroke patients. METHODS The study included 160 acute ischemic stroke patients (male = 87, female = 73, median age = 73 years) with approval from the institutional review board. The patients had undergone CTP imaging, NIHSS and ASPECTS grading. convolutional neural network (CNN) model was trained to fit a raw AIF curve to a gamma variate function. CNN AIF was utilized to estimate the core and penumbra volumes which were further validated with clinical scores. RESULTS Penumbra estimated by CNN AIF correlated positively with the NIHSS score (r = 0.69; p < 0.001) and negatively with the ASPECTS (r = - 0.43; p < 0.001). The CNN AIF estimated penumbra and core volume matching the patient symptoms, typically in patients with higher NIHSS (> 20) and lower ASPECT score (< 5). In group analysis, the median CBF < 20%, CBF < 30%, rCBF < 38%, Tmax > 10 s, Tmax > 10 s volumes were statistically significantly higher (p < .05). CONCLUSIONS With inclusion of the CNN AIF in perfusion imaging pipeline, penumbra and core estimations are more reliable as they correlate with scores representing neurological deficits in stroke. CRITICAL RELEVANCE STATEMENT With CNN AIF perfusion imaging pipeline, penumbra and core estimations are more reliable as they correlate with scores representing neurological deficits in stroke.
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Affiliation(s)
- Sukhdeep Singh Bal
- Department of Mathematical Sciences, University of Liverpool, Liverpool, Merseyside, UK
- Center for Cognition and Mind Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Fan-Pei Gloria Yang
- Center for Cognition and Mind Sciences, National Tsing Hua University, Hsinchu, Taiwan.
- Department of Foreign Languages and Literature, National Tsing Hua University, Hsinchu, Taiwan.
- Department of Radiology, Graduate School of Dentistry, Osaka University, Suita, Japan.
| | - Nai-Fang Chi
- Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Jiu Haw Yin
- Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Tao-Jung Wang
- Department of Computer Science, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Giia Sheun Peng
- Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
- Division of Neurology, Department of Internal Medicine, Taipei Veterans General Hospital, Hsinchu Branch, Hsinchu County, Taipei, Taiwan
| | - Ke Chen
- Department of Mathematical Sciences, University of Liverpool, Liverpool, Merseyside, UK
| | - Ching-Chi Hsu
- Board of Directors, Wizcare Medical Corporation Aggregate, Taichung, Taiwan
| | - Chang-I Chen
- Department of Medical Management, Taipei Medical University, Taipei, Taiwan
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Deak Z, Schuettoff L, Lohse AK, Fabritius M, Reidler P, Forbrig R, Kunz W, Dimitriadis K, Ricke J, Sabel B. Reduction in Radiation Exposure of CT Perfusion by Optimized Imaging Timing Using Temporal Information of the Preceding CT Angiography of the Carotid Artery in the Stroke Protocol. Diagnostics (Basel) 2022; 12:diagnostics12112853. [PMID: 36428913 PMCID: PMC9689781 DOI: 10.3390/diagnostics12112853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/05/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022] Open
Abstract
(1) Background: CT perfusion (CTP) is a fast, robust and widely available but dose-exposing imaging technique for infarct core and penumbra detection. Carotid CT angiography (CTA) can precede CTP in the stroke protocol. Temporal information of the bolus tracking series of CTA could allow for better timing and a decreased number of scans in CTP, resulting in less radiation exposure, if the shortening of CTP does not alter the calculated infarct core and penumbra or the resulting perfusion maps, which are essential for further treatment decisions. (2) Methods: 66 consecutive patients with ischemic stroke proven by follow-up imaging or endovascular intervention were included in this retrospective study approved by the local ethics committee. In each case, six simulated, stepwise shortened CTP examinations were compared with the original data regarding the perfusion maps, infarct core, penumbra and endovascular treatment decision. (3) Results: In simulated CTPs with 26, 28 and 30 scans, the infarct core, penumbra and PRR values were equivalent, and the resulting clinical decision was identical to the original CTP. (4) Conclusions: The temporal information of the bolus tracking series of the carotid CTA can allow for better timing and a lower radiation exposure by eliminating unnecessary scans in CTP.
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Affiliation(s)
- Zsuzsanna Deak
- Imaging Urania, Laurenzerberg 2, 1010 Vienna, Austria
- Correspondence:
| | - Lara Schuettoff
- Department of Radiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Ann-Kathrin Lohse
- Department of Radiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Matthias Fabritius
- Department of Radiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Paul Reidler
- Department of Radiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Robert Forbrig
- Department of Neuroradiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Wolfgang Kunz
- Department of Radiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Konstantin Dimitriadis
- Department of Neurology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Jens Ricke
- Department of Radiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
| | - Bastian Sabel
- Department of Radiology, University Hospital of Munich (LMU), Marchioninistr. 15, 81377 Munich, Germany
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Zeng D, Zeng C, Zeng Z, Li S, Deng Z, Chen S, Bian Z, Ma J. Basis and current state of computed tomography perfusion imaging: a review. Phys Med Biol 2022; 67. [PMID: 35926503 DOI: 10.1088/1361-6560/ac8717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 08/04/2022] [Indexed: 12/30/2022]
Abstract
Computed tomography perfusion (CTP) is a functional imaging that allows for providing capillary-level hemodynamics information of the desired tissue in clinics. In this paper, we aim to offer insight into CTP imaging which covers the basics and current state of CTP imaging, then summarize the technical applications in the CTP imaging as well as the future technological potential. At first, we focus on the fundamentals of CTP imaging including systematically summarized CTP image acquisition and hemodynamic parameter map estimation techniques. A short assessment is presented to outline the clinical applications with CTP imaging, and then a review of radiation dose effect of the CTP imaging on the different applications is presented. We present a categorized methodology review on known and potential solvable challenges of radiation dose reduction in CTP imaging. To evaluate the quality of CTP images, we list various standardized performance metrics. Moreover, we present a review on the determination of infarct and penumbra. Finally, we reveal the popularity and future trend of CTP imaging.
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Affiliation(s)
- Dong Zeng
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Cuidie Zeng
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Zhixiong Zeng
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Sui Li
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Zhen Deng
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Sijin Chen
- Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Zhaoying Bian
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
| | - Jianhua Ma
- School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China; and Guangzhou Key Laboratory of Medical Radiation Imaging and Detection Technology, Southern Medical University, Guangdong 510515, People's Republic of China
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Kramer A, Selbach M, Kerz T, Neulen A, Brockmann MA, Ringel F, Brockmann C. Continuous Intraarterial Nimodipine Infusion for the Treatment of Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage: A Retrospective, Single-Center Cohort Trial. Front Neurol 2022; 13:829938. [PMID: 35370871 PMCID: PMC8964957 DOI: 10.3389/fneur.2022.829938] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/04/2022] [Indexed: 11/14/2022] Open
Abstract
Background Delayed cerebral ischemia (DCI) occurs after aneurysmal subarachnoid hemorrhage (aSAH). Continuous intraarterial nimodipine infusion (CIAN) is a promising approach in patients with intracranial large vessel vasospasm (LVV). The objective of this retrospective single-center cohort study was to evaluate the outcome in aSAH-patients treated with CIAN. Methods CIAN was initiated and ended based on the clinical evaluation and transcranial Doppler (TCD), CT-angiography, CT-perfusion (PCT), and digital subtraction angiography (DSA). Nimodipine (0.5–2.0 mg/h) was administered continuously through microcatheters placed in the extracranial internal carotid and/or vertebral artery. Primary outcome measures were Glasgow Outcome Scale (GOS) at discharge and within 1 year after aSAH, and the occurrence of minor and major (<⅓ and >⅓ of LVV-affected territory) DCI-related infarctions in subsequent CT/MRI-scans. Secondary outcome measures were CIAN-associated complications. Results A total of 17 patients underwent CIAN. Median onset of CIAN was 9 (3–13) days after aSAH, median duration was 5 (1–13) days. A favorable outcome (GOS 4–5) was achieved in 9 patients (53%) at discharge and in 13 patients within 1 year (76%). One patient died of posthemorrhagic cerebral edema. Minor cerebral infarctions occurred in five and major infarctions in three patients. One patient developed cerebral edema possibly due to CIAN. Normalization of PCT-parameters within 2 days was observed in 9/17 patients. Six patients showed clinical response and thus did not require PCT imaging. Conclusion The favorable outcome in 76% of patients after 1 year is in line with previous studies. CIAN thus may be used to treat patients with severe therapy-refractory DCI.
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Affiliation(s)
- Andreas Kramer
- Department of Neurosurgery, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Moritz Selbach
- Department of Neuroradiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Thomas Kerz
- Department of Neurosurgery, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Axel Neulen
- Department of Neurosurgery, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Marc A Brockmann
- Department of Neuroradiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Florian Ringel
- Department of Neurosurgery, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Carolin Brockmann
- Department of Neuroradiology, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
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Cerebral CT Perfusion in Acute Stroke: The Effect of Lowering the Tube Load and Sampling Rate on the Reproducibility of Parametric Maps. Diagnostics (Basel) 2021; 11:diagnostics11061121. [PMID: 34205442 PMCID: PMC8235517 DOI: 10.3390/diagnostics11061121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to define lower dose parameters (tube load and temporal sampling) for CT perfusion that still preserve the diagnostic efficiency of the derived parametric maps. Ninety stroke CT examinations from four clinical sites with 1 s temporal sampling and a range of tube loads (mAs) (100–180) were studied. Realistic CT noise was retrospectively added to simulate a CT perfusion protocol, with a maximum reduction of 40% tube load (mAs) combined with increased sampling intervals (up to 3 s). Perfusion maps from the original and simulated protocols were compared by: (a) similarity using a voxel-wise Pearson’s correlation coefficient r with in-house software; (b) volumetric analysis of the infarcted and hypoperfused volumes using commercial software. Pearson’s r values varied for the different perfusion metrics from 0.1 to 0.85. The mean slope of increase and cerebral blood volume present the highest r values, remaining consistently above 0.7 for all protocol versions with 2 s sampling interval. Reduction of the sampling rate from 2 s to 1 s had only modest impacts on a TMAX volume of 0.4 mL (IQR −1–3) (p = 0.04) and core volume of −1.1 mL (IQR −4–0) (p < 0.001), indicating dose savings of 50%, with no practical loss of diagnostic accuracy. The lowest possible dose protocol was 2 s temporal sampling and a tube load of 100 mAs.
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Canton GP, Luvizutto GJ, Hamamoto Filho PT, Minicucci MF, Modolo GP, Trindade AP, Bazan R, Souza JTD. Safety of the effective radiation dose received during stroke hospitalization. J Vasc Bras 2021; 20:e20210142. [PMID: 35096032 PMCID: PMC8759585 DOI: 10.1590/1677-5449.210142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/27/2021] [Indexed: 11/21/2022] Open
Abstract
Background Neuroimaging is widely used for diagnosis and treatment of stroke. However, little is known about whether the radiation doses received by patients comply with international safety guidelines. Objectives The aim of this study was to evaluate the effective radiation dose received while in hospital for stroke and analyze its safety according to current guidelines. Methods This cross-sectional study included 109 patients who were hospitalized and diagnosed with ischemic stroke. The National Institutes of Health Stroke Scale was used to evaluate stroke severity, the Bamford clinical classification was used for topography, and the TOAST classification was used for etiology. The computed tomography dose index and size-specific dose estimates were used to calculate the effective radiation dose (ERD) received while in hospital. A Mann-Whitney test was used to compare the ERD received by thrombolysed and non-thrombolysed patients. Non-parametric statistics were used to analyze the data with a 95% confidence interval. Results During the study period, the median ERD received was 10.9 mSv. Length of stay was not associated with radiation exposure. No differences were demonstrated in ERD according to stroke etiology or Bamford clinical classification. Patients who had CT perfusion (only or in addition to CT or angiotomography) received the highest ERD (46.5 mSv) and the difference compared to those who did not (10.8 mSv) was statistically significant (p<0.001). No differences were found in the ERD between thrombolysed and non-thrombolysed patients. There was no correlation between ERD while in hospital and stroke severity. Conclusions According to the current national guidelines, the protocol for examining images at our stroke unit is safe in terms of the ERD received by the patient while in hospital. There was no difference in the ERD received by patients stratified by thrombolytic treatment or stroke severity.
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Zhang Y, Peng J, Zeng D, Xie Q, Li S, Bian Z, Wang Y, Zhang Y, Zhao Q, Zhang H, Liang Z, Lu H, Meng D, Ma J. Contrast-Medium Anisotropy-Aware Tensor Total Variation Model for Robust Cerebral Perfusion CT Reconstruction with Low-Dose Scans. IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING 2020; 6:1375-1388. [PMID: 33313342 PMCID: PMC7731921 DOI: 10.1109/tci.2020.3023598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Perfusion computed tomography (PCT) is critical in detecting cerebral ischemic lesions. PCT examination with low-dose scans can effectively reduce radiation exposure to patients at the cost of degraded images with severe noise and artifacts. Tensor total variation (TTV) models are powerful tools that can encode the regional continuous structures underlying a PCT object. In a TTV model, the sparsity structures of the contrast-medium concentration (CMC) across PCT frames are assumed to be isotropic with identical and independent distribution. However, this assumption is inconsistent with practical PCT tasks wherein the sparsity has evident variations and correlations. Such modeling deviation hampers the performance of TTV-based PCT reconstructions. To address this issue, we developed a novel contrast-medium anisotropy-aware tensor total variation (CMAA-TTV) model to describe the intrinsic anisotropy sparsity of the CMC in PCT imaging tasks. Instead of directly on the difference matrices, the CMAA-TTV model characterizes sparsity on a low-rank subspace of the difference matrices which are calculated from the input data adaptively, thus naturally encoding the intrinsic variant and correlated anisotropy sparsity structures of the CMC. We further proposed a robust and efficient PCT reconstruction algorithm to improve low-dose PCT reconstruction performance using the CMAA-TTV model. Experimental studies using a digital brain perfusion phantom, patient data with low-dose simulation and clinical patient data were performed to validate the effectiveness of the presented algorithm. The results demonstrate that the CMAA-TTV algorithm can achieve noticeable improvements over state-of-the-art methods in low-dose PCT reconstruction tasks.
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Affiliation(s)
- Yuanke Zhang
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China, and also with the School of Information Science and Engineering, Qufu Normal University, Rizhao 276826, China
| | - Jiangjun Peng
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Dong Zeng
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Qi Xie
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Sui Li
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Zhaoying Bian
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Yongbo Wang
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
| | - Yong Zhang
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Qian Zhao
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Hao Zhang
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Zhengrong Liang
- Departments of Radiology and Biomedical Engineering, State University of New York at Stony Brook, NY 11794, USA
| | - Hongbing Lu
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China
| | - Deyu Meng
- School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jianhua Ma
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
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Radiation exposure of computed tomography imaging for the assessment of acute stroke. Neuroradiology 2020; 63:511-518. [PMID: 32901338 PMCID: PMC7966220 DOI: 10.1007/s00234-020-02548-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/31/2020] [Indexed: 11/22/2022]
Abstract
Purpose To assess suspected acute stroke, the computed tomography (CT) protocol contains a non-contrast CT (NCCT), a CT angiography (CTA), and a CT perfusion (CTP). Due to assumably high radiation doses of the complete protocol, the aim of this study is to examine radiation exposure and to establish diagnostic reference levels (DRLs). Methods In this retrospective study, dose data of 921 patients with initial CT imaging for suspected acute stroke and dose monitoring with a DICOM header–based tracking and monitoring software were analyzed. Between June 2017 and January 2020, 1655 CT scans were included, which were performed on three different modern multi-slice CT scanners, including 921 NCCT, 465 CTA, and 269 CTP scans. Radiation exposure was reported for CT dose index (CTDIvol) and dose-length product (DLP). DRLs were set at the 75th percentile of dose distribution. Results DRLs were assessed for each step (CTDIvol/DLP): NCCT 33.9 mGy/527.8 mGy cm and CTA 13.7 mGy/478.3 mGy cm. Radiation exposure of CTP was invariable and depended on CT device and its protocol settings with CTDIvol 124.9–258.2 mGy and DLP 1852.6–3044.3 mGy cm. Conclusion Performing complementary CT techniques such as CTA and CTP for the assessment of acute stroke increases total radiation exposure. Hence, the revised DRLs for the complete protocol are required, where our local DRLs may help as benchmarks.
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Walter SS, Maurer M, Storz C, Weiss J, Archid R, Bamberg F, Kim JH, Nikolaou K, Othman AE. Effects of Radiation Dose Reduction on Diagnostic Accuracy of Abdominal CT in Young Adults with Suspected Acute Diverticulitis: A Retrospective Intraindividual Analysis. Acad Radiol 2019; 26:782-790. [PMID: 30268717 DOI: 10.1016/j.acra.2018.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 12/28/2022]
Abstract
RATIONALE AND OBJECTIVES To assess the effects of radiation dose reduction on image quality and diagnostic accuracy of abdominal computed tomography (CT) in young adults with suspected acute diverticulitis. MATERIALS AND METHODS Fifty-four patients ≤40 years who received contrast-enhanced abdominal CT for suspected acute diverticulitis were included. Low-dose CT (LDCT) datasets (25%, 50%, and 75% of the original dose) were generated using sinogram synthesis and quantum noise modeling. A five-point scale was used to assess images qualitatively (overall image quality, noise, artefacts, and sharpness) and for diagnostic confidence (5 being the best possible outcome). Furthermore, the diagnostic accuracy was determined for the presence of acute diverticulitis. RESULTS Among 54 patients (mean age: 35.2 ± 5.3 years, 77.8% male), the prevalence of acute diverticulitis was high (57.4%). Subjective image quality was highest for original datasets and lowest for LDCT datasets with 25% of the original dose (median [interquartile range]: 5 [5] vs. 3 [2-3], p < 0.001). Diagnostic confidence was high for all datasets down to 50% of the original dose, while 25% LDCT datasets were associated with a significantly decreased diagnostic confidence (p < 0.001). Diagnostic accuracy was high for all LDCT and original datasets (sensitivity: 100%, negative predictive value [NPV]: 100% for 75% and 100% dose levels; sensitivity: 96.8%, NPV: 95.8% for 50% dose level; sensitivity: 93.6%, NPV: 91.7% for 25% dose level, respectively). Inter-rater agreement regarding the detection of diverticulitis was almost perfect at doses ≥50% (kappa: >0.81), while lower for datasets of 25% of the original radiation dose agreement (kappa: 0.67-0.78). CONCLUSION Radiation dose reduction down to 50% of the original radiation exposure permits high image quality, diagnostic confidence, and accuracy for the assessment of acute diverticulitis in abdominal CT in young adults without the use of iterative reconstruction algorithms.
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Karwacki GM, Vögele S, Blackham KA. Dose reduction in perfusion CT in stroke patients by lowering scan frequency does not affect automatically calculated infarct core volumes. J Neuroradiol 2019; 46:351-358. [PMID: 31034899 DOI: 10.1016/j.neurad.2019.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 04/04/2019] [Accepted: 04/09/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND AND PURPOSE CT Perfusion technique (CTP) is a quantitative, easily performed, accepted and reliable method for detection of ischemic brain changes. Based on calculated parameters, the size of ischemic penumbra and irreversibly damaged infarct core can be determined which helps guide treatment decisions. However, due to the dynamic nature of the CTP study, it is dose intensive. This study determines the consequences of retrospectively reducing the number of scans in the dynamic acquisition by half on the volume of the automatically calculated infarct core (non-viable tissue) and penumbra (tissue at risk) volumes. Our hypothesis was that equivalent volumetric information could be obtained at a substantial dose savings. MATERIALS AND METHODS Fifty one consecutive patients with occlusion of M1 and/or M2 segment of the middle cerebral artery and ischemic stroke proven by follow-up MRI were included. CTP scans were first analyzed in a standard fashion and automatically generated volumes measured in milliliters were recorded in a database. A second analysis was conducted after removing every second data acquisition from the sequential CTP scans. Automatic volume measurements were repeated, recorded and compared to the initial values obtained using the full dataset. RESULTS The two CTP protocols were statistically equivalent pertaining to automatic infarct core volume calculation but a case-by-case analysis revealed substantial overestimation in some cases. CONCLUSION Reduction of radiation exposure in CTP without objective loss of accuracy of automatically calculated infarct core volume is feasible but might lead to clinically relevant infarct core overestimation in individual cases.
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Affiliation(s)
- Grzegorz Marek Karwacki
- University Hospital Basel, University of Basel, clinic of radiology and nuclear medicine, Basel, Switzerland.
| | - Stephan Vögele
- University Hospital Basel, University of Basel, clinic of radiology and nuclear medicine, Basel, Switzerland
| | - Kristine Ann Blackham
- University Hospital Basel, University of Basel, clinic of radiology and nuclear medicine, Basel, Switzerland
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Radiation dose reduction in perfusion CT imaging of the brain using a 256-slice CT: 80 mAs versus 160 mAs. Clin Imaging 2018; 50:188-193. [DOI: 10.1016/j.clinimag.2018.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 03/12/2018] [Accepted: 03/29/2018] [Indexed: 11/21/2022]
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12
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Rubbert C, Patil KR, Beseoglu K, Mathys C, May R, Kaschner MG, Sigl B, Teichert NA, Boos J, Turowski B, Caspers J. Prediction of outcome after aneurysmal subarachnoid haemorrhage using data from patient admission. Eur Radiol 2018; 28:4949-4958. [PMID: 29948072 DOI: 10.1007/s00330-018-5505-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/23/2018] [Accepted: 04/19/2018] [Indexed: 01/02/2023]
Abstract
OBJECTIVES The pathogenesis leading to poor functional outcome after aneurysmal subarachnoid haemorrhage (aSAH) is multifactorial and not fully understood. We evaluated a machine learning approach based on easily determinable clinical and CT perfusion (CTP) features in the course of patient admission to predict the functional outcome 6 months after ictus. METHODS Out of 630 consecutive subarachnoid haemorrhage patients (2008-2015), 147 (mean age 54.3, 66.7% women) were retrospectively included (Inclusion: aSAH, admission within 24 h of ictus, CTP within 24 h of admission, documented modified Rankin scale (mRS) grades after 6 months. Exclusion: occlusive therapy before first CTP, previous aSAH, CTP not evaluable). A random forests model with conditional inference trees was optimised and trained on sex, age, World Federation of Neurosurgical Societies (WFNS) and modified Fisher grades, aneurysm in anterior vs. posterior circulation, early external ventricular drainage (EVD), as well as MTT and Tmax maximum, mean, standard deviation (SD), range, 75th quartile and interquartile range to predict dichotomised mRS (≤ 2; > 2). Performance was assessed using the balanced accuracy over the training and validation folds using 20 repeats of 10-fold cross-validation. RESULTS In the final model, using 200 trees and the synthetic minority oversampling technique, median balanced accuracy was 84.4% (SD 0.7) over the training folds and 70.9% (SD 1.2) over the validation folds. The five most important features were the modified Fisher grade, age, MTT range, WFNS and early EVD. CONCLUSIONS A random forests model trained on easily determinable features in the course of patient admission can predict the functional outcome 6 months after aSAH with considerable accuracy. KEY POINTS • Features determinable in the course of admission of a patient with aneurysmal subarachnoid haemorrhage (aSAH) can predict the functional outcome 6 months after the occurrence of aSAH. • The top five predictive features were the modified Fisher grade, age, the mean transit time (MTT) range from computed tomography perfusion (CTP), the WFNS grade and the early necessity for an external ventricular drainage (EVD). • The range between the minimum and the maximum MTT may prove to be a valuable biomarker for detrimental functional outcome.
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Affiliation(s)
- Christian Rubbert
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany.
| | - Kaustubh R Patil
- Institute of Neuroscience and Medicine, Brain & Behaviour (INM-7), Research Centre Jülich, D-52425, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Kerim Beseoglu
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, D-40225, Düsseldorf, Germany
| | - Christian Mathys
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
- Institute of Radiology and Neuroradiology, Evangelisches Krankenhaus, University of Oldenburg, D-26122, Oldenburg, Germany
| | - Rebecca May
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
| | - Marius G Kaschner
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
| | - Benjamin Sigl
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
| | - Nikolas A Teichert
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
| | - Johannes Boos
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
| | - Bernd Turowski
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
| | - Julian Caspers
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, D-52425, Jülich, Germany
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Impact of Radiation Dose Reduction in Abdominal Computed Tomography on Diagnostic Accuracy and Diagnostic Performance in Patients with Suspected Appendicitis: An Intraindividual Comparison. Acad Radiol 2018; 25:309-316. [PMID: 29174188 DOI: 10.1016/j.acra.2017.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 09/10/2017] [Accepted: 09/12/2017] [Indexed: 11/20/2022]
Abstract
RATIONALE AND OBJECTIVES To determine the intraindividual impact of radiation dose reduction in abdominal computed tomography (CT) on diagnostic performance in patients with suspected appendicitis. MATERIALS AND METHODS This study was approved by the institutional review board. Seventy-five patients who underwent standard contrast-enhanced abdominal CT for suspected appendicitis between 2004 and 2009 were retrospectively included. Low-dose CT reconstructions with 75%, 50%, and 25% of the original radiation dose level were generated by applying realistic reduced-dose simulation. Two blinded, independent readers assessed image quality, signal-to-noise ratio, and diagnostic confidence on each dataset. Diagnostic accuracy for detection of appendicitis and complications were calculated for each reader. Paired univariate tests were used to determine intraindividual differences. RESULTS Among 75 subjects included in the analysis (57% female, mean age: 41 ± 18 years), the prevalence of histopathologically confirmed appendicitis was 59%. Signal-to-noise ratio and subjective image quality of 50% and 25% reduced-dose CTs were significantly lower than the reference datasets (all P < .005). Appendicitis was correctly identified in all reference and low-dose datasets (sensitivity: 100%, negative predictive value: 100%). Presence of complications was correctly detected in all reference, 75%, and 50% datasets, but was decreased in 25% datasets (sensitivity: 77.8% and negative predictive value: 97.4%). Diagnostic confidence was high for original and 75% datasets, but significantly lower for 50% and 25% datasets (P < .001). CONCLUSIONS Our results indicate that diagnostic accuracy in abdominal CT acquisitions acquired at 75% and 50% of radiation dose is maintained in patients with suspected appendicitis, whereas further reduction of radiation exposition is associated with decreased diagnostic performance.
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Afat S, Brockmann C, Nikoubashman O, Müller M, Thierfelder KM, Brockmann MA, Nikolaou K, Wiesmann M, Kim JH, Othman AE. Diagnostic Accuracy of Simulated Low-Dose Perfusion CT to Detect Cerebral Perfusion Impairment after Aneurysmal Subarachnoid Hemorrhage: A Retrospective Analysis. Radiology 2018; 287:643-650. [PMID: 29309735 DOI: 10.1148/radiol.2017162707] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purpose To evaluate diagnostic accuracy of low-dose volume perfusion (VP) computed tomography (CT) compared with original VP CT regarding the detection of cerebral perfusion impairment after aneurysmal subarachnoid hemorrhage. Materials and Methods In this retrospective study, 85 patients (mean age, 59.6 years; 62 women) with aneurysmal subarachnoid hemorrhage and who were suspected of having cerebral vasospasm at unenhanced CT and VP CT (tube voltage, 80 kVp; tube current-time product, 180 mAs) were included, 37 of whom underwent digital subtraction angiography (DSA) within 6 hours. Low-dose VP CT data sets at tube current-time product of 72 mAs were retrospectively generated by validated realistic simulation. Perfusion maps were generated from both data sets and reviewed by two neuroradiologists for overall image quality, diagnostic confidence and presence and/or severity of perfusion impairment indicating vasospasm. An interventional neuroradiologist evaluated 16 vascular segments at DSA. Diagnostic accuracy of low-dose VP CT was calculated with original VP CT as reference standard. Agreement between findings of both data sets was assessed by using weighted Cohen κ and findings were correlated with DSA by using Spearman correlation. After quantitative volumetric analysis, lesion volumes were compared on both VP CT data sets. Results Low-dose VP CT yielded good ratings of image quality and diagnostic confidence and classified all patients correctly with high diagnostic accuracy (sensitivity, 99.0%; specificity, 99.5%) without significant differences regarding presence and/or severity of perfusion impairment between original and low-dose data sets (Z = -0.447; P = .655). Findings of both data sets correlated significantly with DSA (original, r = 0.671; low dose, r = 0.667). Lesion volume was comparable for both data sets (relative difference, 5.9% ± 5.1 [range, 0.2%-25.0%; median, 4.0%]) with strong correlation (r = 0.955). Conclusion The results suggest that radiation dose reduction to 40% of original dose levels (tube current-time product, 72 mAs) may be performed in VP CT imaging of patients with aneurysmal subarachnoid hemorrhage without compromising the diagnostic accuracy regarding detection of cerebral perfusion impairment indicating vasospasm. © RSNA, 2018 Online supplemental material is available for this article.
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Affiliation(s)
- Saif Afat
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Carolin Brockmann
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Omid Nikoubashman
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Marguerite Müller
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Kolja M Thierfelder
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Marc A Brockmann
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Konstantin Nikolaou
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Martin Wiesmann
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Jong Hyo Kim
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
| | - Ahmed E Othman
- From the Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany (S.A., O.N., M.M., M.W., A.E.O.); Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany (S.A., K.N., A.E.O.); Department of Neuroradiology, University Hospital Mainz, Mainz, Germany (M.A.B., C.B.); Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Germany (K.M.T.); Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea (J.H.K.); Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea (J.H.K.); and Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon, South Korea (J.H.K.)
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Othman AE, Bongers MN, Zinsser D, Schabel C, Wichmann JL, Arshid R, Notohamiprodjo M, Nikolaou K, Bamberg F. Evaluation of reduced-dose CT for acute non-traumatic abdominal pain: evaluation of diagnostic accuracy in comparison to standard-dose CT. Acta Radiol 2018; 59:4-12. [PMID: 28406049 DOI: 10.1177/0284185117703152] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Background Patients with acute non-traumatic abdominal pain often undergo abdominal computed tomography (CT). However, abdominal CT is associated with high radiation exposure. Purpose To evaluate diagnostic performance of a reduced-dose 100 kVp CT protocol with advanced modeled iterative reconstruction as compared to a linearly blended 120 kVp protocol for assessment of acute, non-traumatic abdominal pain. Material and Methods Two radiologists assessed 100 kVp and linearly blended 120 kVp series of 112 consecutive patients with acute non-traumatic pain (onset < 48 h) regarding image quality, noise, and artifacts on a five-point Likert scale. Both radiologists assessed both series for abdominal pathologies and for diagnostic confidence. Both 100 kVp and linearly blended 120 kVp series were quantitatively evaluated regarding radiation dose and image noise. Comparative statistics and diagnostic accuracy was calculated using receiver operating curve (ROC) statistics, with final clinical diagnosis/clinical follow-up as reference standard. Results Image quality was high for both series without detectable significant differences ( P = 0.157). Image noise and artifacts were rated low for both series but significantly higher for 100 kVp ( P ≤ 0.021). Diagnostic accuracy was high for both series (120 kVp: area under the curve [AUC] = 0.950, sensitivity = 0.958, specificity = 0.941; 100 kVp: AUC ≥ 0.910, sensitivity ≥ 0.937, specificity = 0.882; P ≥ 0.516) with almost perfect inter-rater agreement (Kappa = 0.939). Diagnostic confidence was high for both dose levels without significant differences (100 kVp 5, range 4-5; 120 kVp 5, range 3-5; P = 0.134). The 100 kVp series yielded 26.1% lower radiation dose compared with the 120 kVp series (5.72 ± 2.23 mSv versus 7.75 ± 3.02 mSv, P < 0.001). Image noise was significantly higher in reduced-dose CT (13.3 ± 2.4 HU versus 10.6 ± 2.1 HU; P < 0.001). Conclusion Reduced-dose abdominal CT using 100 kVp yields excellent image quality and high diagnostic accuracy for the assessment of acute non-traumatic abdominal pain.
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Affiliation(s)
- Ahmed E Othman
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Malte Niklas Bongers
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Dominik Zinsser
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Christoph Schabel
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Julian L Wichmann
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt, Germany
| | - Rami Arshid
- Department of General, Visceral and Transplantation Surgery, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Mike Notohamiprodjo
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Konstantin Nikolaou
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Fabian Bamberg
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
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16
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Radiation dose reduction in perfusion CT imaging of the brain: A review of the literature. J Neuroradiol 2016; 43:1-5. [DOI: 10.1016/j.neurad.2015.06.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 06/04/2015] [Accepted: 06/10/2015] [Indexed: 11/30/2022]
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17
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Othman AE, Afat S, Brockmann C, Nikoubashman O, Bier G, Brockmann MA, Nikolaou K, Tai JH, Yang ZP, Kim JH, Wiesmann M. Low-Dose Volume-Perfusion CT of the Brain: Effects of Radiation Dose Reduction on Performance of Perfusion CT Algorithms. Clin Neuroradiol 2015; 27:311-318. [PMID: 26669592 DOI: 10.1007/s00062-015-0489-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE We aimed to compare different computed tomography (CT) perfusion post-processing algorithms regarding image quality of perfusion maps from low-dose volume perfusion CT (VPCT) and their diagnostic performance regarding the detection of ischemic brain lesions. METHODS AND MATERIALS We included VPCT data of 21 patients with acute stroke (onset < 6h), which were acquired at 80 kV and 180 mAs. Low-dose VPCT datasets with 72 mAs (40 % of original dose) were generated using realistic low-dose simulation. Perfusion maps (cerebral blood volume (CBV); cerebral blood flow (CBF) from original and low-dose datasets were generated using two different commercially available post-processing methods: deconvolution-based method (DC) and maximum slope algorithm (MS). The resulting DC and MS perfusion maps were compared regarding perfusion values, signal-to-noise ratio (SNR) as well as image quality and diagnostic accuracy as rated by two blinded neuroradiologists. RESULTS Quantitative perfusion parameters highly correlated for both algorithms and both dose levels (r ≥ 0.613, p < 0.001). Regarding SNR levels and image quality of the CBV maps, no significant differences between DC and MS were found (p ≥ 0.683). Low-dose MS CBF maps yielded significantly higher SNR levels (p < 0.001) and quality scores (p = 0.014) than those of DC. Low-dose CBF and CBV maps from both DC and MS yielded high sensitivity and specificity for the detection of ischemic lesions (sensitivity ≥ 0.82, specificity ≥ 0.90). CONCLUSION Our results indicate that both methods produce diagnostically sufficient perfusion maps from simulated low-dose VPCT. However, MS produced CBF maps with significantly higher image quality and SNR than DC, indicating that MS might be more suitable for low-dose VPCT imaging.
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Affiliation(s)
- A E Othman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany.,Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - S Afat
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - C Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - O Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - G Bier
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - M A Brockmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
| | - K Nikolaou
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - J H Tai
- Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, 433-270, Suwon, South Korea
| | - Z P Yang
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, 433-270, Suwon, South Korea
| | - J H Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, 433-270, Suwon, South Korea. .,Department of Radiology, Seoul National University College of Medicine, 101 Daehak-Ro, Chongno-gu, 110-744, Seoul, South Korea. .,Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, 433-270, Suwon, South Korea.
| | - M Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, 52074, Aachen, Germany
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Impact of image denoising on image quality, quantitative parameters and sensitivity of ultra-low-dose volume perfusion CT imaging. Eur Radiol 2015; 26:167-74. [DOI: 10.1007/s00330-015-3853-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/20/2015] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
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