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Ichikawa S, Ozaki M, Itadani H, Sugimori H, Kondo Y. Deep learning-based correction for time truncation in cerebral computed tomography perfusion. Radiol Phys Technol 2024:10.1007/s12194-024-00818-6. [PMID: 38861134 DOI: 10.1007/s12194-024-00818-6] [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: 03/31/2024] [Revised: 05/15/2024] [Accepted: 05/31/2024] [Indexed: 06/12/2024]
Abstract
Cerebral computed tomography perfusion (CTP) imaging requires complete acquisition of contrast bolus inflow and washout in the brain parenchyma; however, time truncation undoubtedly occurs in clinical practice. To overcome this issue, we proposed a three-dimensional (two-dimensional + time) convolutional neural network (CNN)-based approach to predict missing CTP image frames at the end of the series from earlier acquired image frames. Moreover, we evaluated three strategies for predicting multiple time points. Seventy-two CTP scans with 89 frames and eight slices from a publicly available dataset were used to train and test the CNN models capable of predicting the last 10 image frames. The prediction strategies were single-shot prediction, recursive multi-step prediction, and direct-recursive hybrid prediction.Single-shot prediction predicted all frames simultaneously, while recursive multi-step prediction used prior predictions as input for subsequent steps, and direct-recursive hybrid prediction employed separate models for each step with prior predictions as input for the next step. The accuracies of the predicted image frames were evaluated in terms of image quality, bolus shape, and clinical perfusion parameters. We found that the image quality metrics were superior when multiple CTP images were predicted simultaneously rather than recursively. The bolus shape also showed the highest correlation (r = 0.990, p < 0.001) and the lowest variance (95% confidence interval, -453.26-445.53) in the single-shot prediction. For all perfusion parameters, the single-shot prediction had the smallest absolute differences from ground truth. Our proposed approach can potentially minimize time truncation errors and support the accurate quantification of ischemic stroke.
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Affiliation(s)
- Shota Ichikawa
- Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Niigata University, 2-746 Asahimachi-Dori, Chuo-ku, Niigata, 951-8518, Japan.
- Institute for Research Administration, Niigata University, 8050 Ikarashi 2-No-cho, Nishi-ku, Niigata, 950-2181, Japan.
| | - Makoto Ozaki
- Department of Radiological Technology, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama, 710-8602, Japan
| | - Hideki Itadani
- Department of Radiological Technology, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama, 710-8602, Japan
| | - Hiroyuki Sugimori
- Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, 060-0812, Japan
| | - Yohan Kondo
- Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Niigata University, 2-746 Asahimachi-Dori, Chuo-ku, Niigata, 951-8518, Japan
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Oh G, Moon Y, Moon WJ, Ye JC. Unpaired deep learning for pharmacokinetic parameter estimation from dynamic contrast-enhanced MRI without AIF measurements. Neuroimage 2024; 291:120571. [PMID: 38518829 DOI: 10.1016/j.neuroimage.2024.120571] [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: 11/23/2023] [Revised: 02/28/2024] [Accepted: 03/08/2024] [Indexed: 03/24/2024] Open
Abstract
DCE-MRI provides information about vascular permeability and tissue perfusion through the acquisition of pharmacokinetic parameters. However, traditional methods for estimating these pharmacokinetic parameters involve fitting tracer kinetic models, which often suffer from computational complexity and low accuracy due to noisy arterial input function (AIF) measurements. Although some deep learning approaches have been proposed to tackle these challenges, most existing methods rely on supervised learning that requires paired input DCE-MRI and labeled pharmacokinetic parameter maps. This dependency on labeled data introduces significant time and resource constraints and potential noise in the labels, making supervised learning methods often impractical. To address these limitations, we present a novel unpaired deep learning method for estimating pharmacokinetic parameters and the AIF using a physics-driven CycleGAN approach. Our proposed CycleGAN framework is designed based on the underlying physics model, resulting in a simpler architecture with a single generator and discriminator pair. Crucially, our experimental results indicate that our method does not necessitate separate AIF measurements and produces more reliable pharmacokinetic parameters than other techniques.
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Affiliation(s)
- Gyutaek Oh
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, 34141, Daejeon, Republic of Korea
| | - Yeonsil Moon
- Department of Neurology, Konkuk University Medical Center, 120-1, Neungdong-ro, Gwangjin-gu, 05030, Seoul, Republic of Korea
| | - Won-Jin Moon
- Department of Radiology, Konkuk University Medical Center, 120-1, Neungdong-ro, Gwangjin-gu, 05030, Seoul, Republic of Korea.
| | - Jong Chul Ye
- Kim Jaechul Graduate School of AI, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, 34141, Daejeon, Republic of Korea.
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Ladumor H, Vilanilam GK, Ameli S, Pandey I, Vattoth S. CT perfusion in stroke: Comparing conventional and RAPID automated software. Curr Probl Diagn Radiol 2024; 53:201-207. [PMID: 37891080 DOI: 10.1067/j.cpradiol.2023.10.011] [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: 06/02/2023] [Revised: 09/12/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023]
Abstract
CT perfusion (CTP) imaging is increasingly used for routine evaluation of acute ischemic stroke. Knowledge about the different types of CTP software, imaging acquisition and post-processing, and interpretation is crucial for appropriate patient selection for reperfusion therapy. Conventional vendor-provided CTP software differentiates between ischemic penumbra and core infarct using the tiebreaker of critically reduced cerebral blood volume (CBV) values within brain regions showing abnormally elevated time parameters like mean transit time (MTT) or time to peak (TTP). On the other hand, RAPID automated software differentiates between ischemic penumbra and core infarct using the tiebreaker of critically reduced cerebral blood flow (CBF) values within brain regions showing abnormally elevated time to maximum (Tmax). Additionally, RAPID calculates certain indices that confer prognostic value, such as the hypoperfusion and CBV index. In this review, we aim to familiarize the reader with the technical principles of CTP imaging, compare CTP maps generated by conventional and RAPID software, and discuss important thresholds for reperfusion and prognostic indices. Lastly, we discuss common pitfalls to help with the accurate interpretation of CTP imaging.
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Affiliation(s)
- Heta Ladumor
- Department of Radiology, University of Arkansas for Medical Sciences, 4301 W. Markham St - Slot 556, Little Rock, AR 72205, USA.
| | - George K Vilanilam
- Department of Radiology, University of Arkansas for Medical Sciences, 4301 W. Markham St - Slot 556, Little Rock, AR 72205, USA
| | - Sanaz Ameli
- Department of Radiology, University of Arkansas for Medical Sciences, 4301 W. Markham St - Slot 556, Little Rock, AR 72205, USA
| | | | - Surjith Vattoth
- Deparment of Diagnostic Radiology & Nuclear Medicine, Division of Neuroradiology, Rush University Medical Center, Chicago, IL 60612, USA
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Li MD, Jaremko JL. Personalizing Short-term Fracture Prevention After Hip Fracture: CT-based AI Risk Stratification. Radiology 2024; 310:e233396. [PMID: 38289218 DOI: 10.1148/radiol.233396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Affiliation(s)
- Matthew D Li
- From the Department of Radiology and Diagnostic Imaging, Faculty of Medicine and Dentistry, University of Alberta Hospital, 8440 112 St NW, 2A2.41 WMC, Edmonton, AB, Canada T6G 2B7
| | - Jacob L Jaremko
- From the Department of Radiology and Diagnostic Imaging, Faculty of Medicine and Dentistry, University of Alberta Hospital, 8440 112 St NW, 2A2.41 WMC, Edmonton, AB, Canada T6G 2B7
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Fainardi E, Busto G, Morotti A. Automated advanced imaging in acute ischemic stroke. Certainties and uncertainties. Eur J Radiol Open 2023; 11:100524. [PMID: 37771657 PMCID: PMC10523426 DOI: 10.1016/j.ejro.2023.100524] [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: 05/30/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/30/2023] Open
Abstract
The purpose of this is study was to review pearls and pitfalls of advanced imaging, such as computed tomography perfusion and diffusion-weighed imaging and perfusion-weighted imaging in the selection of acute ischemic stroke (AIS) patients suitable for endovascular treatment (EVT) in the late time window (6-24 h from symptom onset). Advanced imaging can quantify infarct core and ischemic penumbra using specific threshold values and provides optimal selection parameters, collectively called target mismatch. More precisely, target mismatch criteria consist of core volume and/or penumbra volume and mismatch ratio (the ratio between total hypoperfusion and core volumes) with precise cut-off values. The parameters of target mismatch are automatically calculated with dedicated software packages that allow a quick and standardized interpretation of advanced imaging. However, this approach has several limitations leading to a misclassification of core and penumbra volumes. In fact, automatic software platforms are affected by technical artifacts and are not interchangeable due to a remarkable vendor-dependent variability, resulting in different estimate of target mismatch parameters. In addition, advanced imaging is not completely accurate in detecting infarct core, that can be under- or overestimated. Finally, the selection of candidates for EVT remains currently suboptimal due to the high rates of futile reperfusion and overselection caused by the use of very stringent inclusion criteria. For these reasons, some investigators recently proposed to replace advanced with conventional imaging in the selection for EVT, after the demonstration that non-contrast CT ASPECTS and computed tomography angiography collateral evaluation are not inferior to advanced images in predicting outcome in AIS patients treated with EVT. However, other authors confirmed that CTP and PWI/DWI postprocessed images are superior to conventional imaging in establishing the eligibility of patients for EVT. Therefore, the routine application of automatic assessment of advanced imaging remains a matter of debate. Recent findings suggest that the combination of conventional and advanced imaging might improving our selection criteria.
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Affiliation(s)
- Enrico Fainardi
- Neuroradiology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Italy
- Neuroradiology Unit, Department of Radiology, Careggi University Hospital, Florence, Italy
| | - Giorgio Busto
- Neuroradiology Unit, Department of Radiology, Careggi University Hospital, Florence, Italy
| | - Andrea Morotti
- Department of Neurological and Vision Sciences, Neurology Unit, ASST Spedali Civili, Brescia, Italy
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Ozkara BB, Karabacak M, Margetis K, Yedavalli VS, Wintermark M, Bisdas S. Assessment of Computed Tomography Perfusion Research Landscape: A Topic Modeling Study. Tomography 2023; 9:2016-2028. [PMID: 37987344 PMCID: PMC10661298 DOI: 10.3390/tomography9060158] [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: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/22/2023] Open
Abstract
The number of scholarly articles continues to rise. The continuous increase in scientific output poses a challenge for researchers, who must devote considerable time to collecting and analyzing these results. The topic modeling approach emerges as a novel response to this need. Considering the swift advancements in computed tomography perfusion (CTP), we deem it essential to launch an initiative focused on topic modeling. We conducted a comprehensive search of the Scopus database from 1 January 2000 to 16 August 2023, to identify relevant articles about CTP. Using the BERTopic model, we derived a group of topics along with their respective representative articles. For the 2020s, linear regression models were used to identify and interpret trending topics. From the most to the least prevalent, the topics that were identified include "Tumor Vascularity", "Stroke Assessment", "Myocardial Perfusion", "Intracerebral Hemorrhage", "Imaging Optimization", "Reperfusion Therapy", "Postprocessing", "Carotid Artery Disease", "Seizures", "Hemorrhagic Transformation", "Artificial Intelligence", and "Moyamoya Disease". The model provided insights into the trends of the current decade, highlighting "Postprocessing" and "Artificial Intelligence" as the most trending topics.
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Affiliation(s)
- Burak B. Ozkara
- Department of Neuroradiology, MD Anderson Cancer Center, 1400 Pressler Street, Houston, TX 77030, USA
| | - Mert Karabacak
- Department of Neurosurgery, Mount Sinai Health System, 1468 Madison Avenue, New York, NY 10029, USA
| | - Konstantinos Margetis
- Department of Neurosurgery, Mount Sinai Health System, 1468 Madison Avenue, New York, NY 10029, USA
| | - Vivek S. Yedavalli
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins Hospital, 600 N Wolfe Street, Baltimore, MD 21287, USA
| | - Max Wintermark
- Department of Neuroradiology, MD Anderson Cancer Center, 1400 Pressler Street, Houston, TX 77030, USA
| | - Sotirios Bisdas
- Department of Neuroradiology, The National Hospital for Neurology and Neurosurgery, University College London NHS Foundation Trust, London WC1N 3BG, UK
- Department of Brain Repair and Rehabilitation, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
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Cerebral perfusion imaging predicts final infarct volume after basilar artery thrombectomy. J Stroke Cerebrovasc Dis 2023; 32:106866. [PMID: 36427471 DOI: 10.1016/j.jstrokecerebrovasdis.2022.106866] [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: 09/02/2022] [Revised: 10/19/2022] [Accepted: 10/25/2022] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES Cerebral perfusion imaging may be used to identify the ischemic core in acute ischemic stroke (AIS) patients with a large vessel occlusion of the anterior circulation; however, perfusion parameters that predict the ischemic core in AIS patients with a basilar artery occlusion (BAO) are poorly described. We determined which cerebral perfusion parameters best predict the ischemic core after successful endovascular thrombectomy (EVT) in BAO patients. MATERIALS AND METHODS We performed multicenter retrospective study of BAO patients with perfusion imaging before EVT and a DWI after successful EVT. The ischemic core was defined as regions on CTP, which were co-registered to the final DWI infarct. Various time-to-maximum (Tmax) and cerebral blood flow (CBF) thresholds were compared to final infarct volume to determine the best predictor of the final infarct. RESULTS 28 patients were included in the analysis for this study. Tmax >8s (r2: 0.56; median absolute error, 16.0 mL) and Tmax >10s (r2: 0.73; median absolute error, 11.3 mL) showed the strongest agreement between the pre-EVT CTP study and the final DWI. CBF <38% (r2: 0.76; median absolute error, 8.2 mL) and CBF <34% (r2: 0.76; median absolute error, 9.1 mL) also correlated well with final infarct volume on DWI. CONCLUSIONS Pre-EVT CT perfusion imaging is useful to predict the final ischemic infarct volume in BAO patients. Tmax >8s and Tmax >10s were the strongest predictors of the post-EVT final infarct volume.
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Chartampilas E, Rafailidis V, Georgopoulou V, Kalarakis G, Hatzidakis A, Prassopoulos P. Current Imaging Diagnosis of Hepatocellular Carcinoma. Cancers (Basel) 2022; 14:cancers14163997. [PMID: 36010991 PMCID: PMC9406360 DOI: 10.3390/cancers14163997] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/10/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022] Open
Abstract
Simple Summary The role of imaging in the management of hepatocellular carcinoma (HCC) has significantly evolved and expanded beyond the plain radiological confirmation of the tumor based on the typical appearance in a multiphase contrast-enhanced CT or MRI examination. The introduction of hepatobiliary contrast agents has enabled the diagnosis of hepatocarcinogenesis at earlier stages, while the application of ultrasound contrast agents has drastically upgraded the role of ultrasound in the diagnostic algorithms. Newer quantitative techniques assessing blood perfusion on CT and MRI not only allow earlier diagnosis and confident differentiation from other lesions, but they also provide biomarkers for the evaluation of treatment response. As distinct HCC subtypes are identified, their correlation with specific imaging features holds great promise for estimating tumor aggressiveness and prognosis. This review presents the current role of imaging and underlines its critical role in the successful management of patients with HCC. Abstract Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer related death worldwide. Radiology has traditionally played a central role in HCC management, ranging from screening of high-risk patients to non-invasive diagnosis, as well as the evaluation of treatment response and post-treatment follow-up. From liver ultrasonography with or without contrast to dynamic multiple phased CT and dynamic MRI with diffusion protocols, great progress has been achieved in the last decade. Throughout the last few years, pathological, biological, genetic, and immune-chemical analyses have revealed several tumoral subtypes with diverse biological behavior, highlighting the need for the re-evaluation of established radiological methods. Considering these changes, novel methods that provide functional and quantitative parameters in addition to morphological information are increasingly incorporated into modern diagnostic protocols for HCC. In this way, differential diagnosis became even more challenging throughout the last few years. Use of liver specific contrast agents, as well as CT/MRI perfusion techniques, seem to not only allow earlier detection and more accurate characterization of HCC lesions, but also make it possible to predict response to treatment and survival. Nevertheless, several limitations and technical considerations still exist. This review will describe and discuss all these imaging modalities and their advances in the imaging of HCC lesions in cirrhotic and non-cirrhotic livers. Sensitivity and specificity rates, method limitations, and technical considerations will be discussed.
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Affiliation(s)
- Evangelos Chartampilas
- Radiology Department, AHEPA University Hospital, Medical School, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece
- Correspondence:
| | - Vasileios Rafailidis
- Radiology Department, AHEPA University Hospital, Medical School, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece
| | - Vivian Georgopoulou
- Radiology Department, Ippokratio General Hospital of Thessaloniki, 54642 Thessaloniki, Greece
| | - Georgios Kalarakis
- Department of Diagnostic Radiology, Karolinska University Hospital, 14152 Stockholm, Sweden
- Department of Clinical Science, Division of Radiology, Intervention and Technology (CLINTEC), Karolinska Institutet, 14152 Stockholm, Sweden
- Department of Radiology, Medical School, University of Crete, 71500 Heraklion, Greece
| | - Adam Hatzidakis
- Radiology Department, AHEPA University Hospital, Medical School, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece
| | - Panos Prassopoulos
- Radiology Department, AHEPA University Hospital, Medical School, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece
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