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Computed Tomography Techniques, Protocols, Advancements, and Future Directions in Liver Diseases. Magn Reson Imaging Clin N Am 2021; 29:305-320. [PMID: 34243919 DOI: 10.1016/j.mric.2021.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Computed tomography (CT) is often performed as the initial imaging study for the workup of patients with known or suspected liver disease. Our article reviews liver CT techniques and protocols in clinical practice along with updates on relevant CT advances, including wide-detector CT, radiation dose optimization, and multienergy scanning, that have already shown clinical impact. Particular emphasis is placed on optimizing the late arterial phase of enhancement, which is critical to evaluation of hepatocellular carcinoma. We also discuss emerging techniques that may soon influence clinical care.
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Effect of energy level on the spatial resolution and noise frequency characteristics of virtual monochromatic images: a phantom experiment using four types of CT scanners. Jpn J Radiol 2021; 40:94-102. [PMID: 34304382 DOI: 10.1007/s11604-021-01180-y] [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: 04/04/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE The purpose of the study is to evaluate the effect of energy level on the modulation transfer functions (MTF) and noise power spectra (NPS) of virtual monochromatic images (VMIs) obtained using four types of computed-tomographic (CT) scanners: Revolution, SOMATOM, IQon, and Aquilion. MATERIALS AND METHODS VMIs were obtained at 70, 60, and 50 kiloelectron volts (keV), and also at the lowest keV available in each scanner. We evaluated the MTF and NPS in the VMIs obtained at each keV. RESULTS No significant effect of the energy level on the MTF was observed in IQon, whereas the spatial resolution decreased as the energy level decreased in the other types of scanners. The NPS curves tended to increase as the energy levels decreased with three types of scanners other than Aquilion. CONCLUSION The spatial resolution and noise frequency characteristics of VMIs may be affected by the energy level, and the effects of energy level on these characteristics differ depending on the type of CT scanners.
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Majeed NF, Braschi Amirfarzan M, Wald C, Wortman JR. Spectral detector CT applications in advanced liver imaging. Br J Radiol 2021; 94:20201290. [PMID: 34048285 PMCID: PMC8248211 DOI: 10.1259/bjr.20201290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 04/16/2021] [Accepted: 05/13/2021] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE Spectral detector CT (SDCT) has many applications in advanced liver imaging. If appropriately utilized, this technology has the potential to improve image quality, provide new diagnostic information, and allow for decreased radiation dose. The purpose of this review is to familiarize radiologists with the uses of SDCT in liver imaging. CONCLUSION SDCT has a variety of post-processing techniques, which can be used in advanced liver imaging and can significantly add value in clinical practice.
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Affiliation(s)
- Noor Fatima Majeed
- Department of Radiology, Lahey Hospital and Medical Center, 41 Burlington Mall Road, Burlington, United States
| | - Marta Braschi Amirfarzan
- Department of Radiology, Lahey Hospital and Medical Center, 41 Burlington Mall Road, Burlington, United States
| | - Christoph Wald
- Department of Radiology, Lahey Hospital and Medical Center, 41 Burlington Mall Road, Burlington, United States
| | - Jeremy R Wortman
- Department of Radiology, Lahey Hospital and Medical Center, 41 Burlington Mall Road, Burlington, United States
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Jhaveri KS, Babaei Jandaghi A, Thipphavong S, Espin-Garcia O, Dodd A, Hutchinson S, Reichman TW, Moulton CA, McGilvary ID, Gallinger S. Can preoperative liver MRI with gadoxetic acid help reduce open-close laparotomies for curative intent pancreatic cancer surgery? Cancer Imaging 2021; 21:45. [PMID: 34193282 PMCID: PMC8243548 DOI: 10.1186/s40644-021-00416-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/18/2021] [Indexed: 12/17/2022] Open
Abstract
Objectives To evaluate gadoxetic acid-enhanced liver MRI (EOB-MRI) versus contrast-enhanced computed tomography (CECT) for preoperative detection of liver metastasis (LM) and reduction of open-close laparotomies for pancreatic ductal adenocarcinoma (PDAC). Methods Sixty-six patients with PDAC had undergone preoperative EOB-MRI and CECT. LM detection by EOB-MRI and CECT and their impact on surgical planning, open-close laparotomies were compared by clinical and radiology reports and retrospective analysis of imaging by two blinded independent readers. Histopathology or imaging follow-up was the reference standard. Statistical analysis was performed at patient and lesion levels with two-sided McNemar tests. Results EOB-MRI showed higher sensitivity versus CECT (71.7% [62.1-80.0] vs. 34% [25.0-43.8]; p = 0.009), comparable specificity (98.6%, [96.9-99.5] vs. 100%, [99.1-100], and higher AUROC (85.1%, [80.4-89.9] vs. 66.9%, [60.9-73.1]) for LM detection. An incremental 7.6% of patients were excluded from surgery with a potential reduction of up to 13.6% in futile open-close laparotomies due to LM detected on EOB-MRI only. Conclusions Preoperative EOB-MRI has superior diagnostic performance in detecting LM from PDAC. This better informs surgical eligibility with potential reduction of futile open-close laparotomies from attempted curative intent pancreatic cancer surgery. Supplementary Information The online version contains supplementary material available at 10.1186/s40644-021-00416-4.
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Affiliation(s)
- Kartik S Jhaveri
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital and Women's College Hospital, University of Toronto, 610 University Ave, 3-957, Toronto, ON, M5G 2M9, Canada.
| | - Ali Babaei Jandaghi
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital and Women's College Hospital, Toronto, ON, M5G 1X6, Canada
| | - Seng Thipphavong
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital and Women's College Hospital, University of Toronto, 610 University Ave, 3-957, Toronto, ON, M5G 2M9, Canada
| | - Osvaldo Espin-Garcia
- Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 2C1, Canada.,Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Anna Dodd
- Wallace McCain Centre for Pancreatic Cancer, Princess Margaret Hospital Cancer Centre, Toronto, ON, M5G 2C1, Canada
| | - Shawn Hutchinson
- Wallace McCain Centre for Pancreatic Cancer, Princess Margaret Hospital Cancer Centre, Toronto, ON, M5G 2C1, Canada
| | - Trevor W Reichman
- Department of Surgery, University of Toronto; Hepatobiliary & Pancreatic Surgical Oncology, University Health Network, Toronto, ON, M5G 2C4, Canada
| | - Carol-Anne Moulton
- Department of Surgery, University of Toronto; Hepatobiliary & Pancreatic Surgical Oncology, University Health Network, Toronto, ON, M5G 2C4, Canada
| | - Ian D McGilvary
- Department of Surgery, Hepatobiliary & Pancreatic Surgical Oncology, University Health Network, University of Toronto, Toronto, ON, M5G 2N2, Canada
| | - Steven Gallinger
- Department of Surgery, Hepatobiliary & Pancreatic Surgical Oncology, University Health Network, University of Toronto, Toronto, ON, M5G 2N2, Canada
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Basso L, Baldi D, Mannelli L, Cavaliere C, Salvatore M, Brancato V. Investigating Dual-Energy CT Post-Contrast Phases for Liver Iron Quantification: A Preliminary Study. Dose Response 2021; 19:15593258211011359. [PMID: 34121963 PMCID: PMC8173994 DOI: 10.1177/15593258211011359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/17/2021] [Accepted: 03/29/2021] [Indexed: 12/03/2022] Open
Abstract
Background and Purpose: Quantification of hepatic virtual iron content (VIC) by using Multidetector Dual Energy Computed Tomography (DECT) has been recently investigated since this technique could offer a good compromise between accuracy and non-invasiveness for liver iron content quantification. The aim of our study is to investigate differences in VIC at different DECT time points (namely baseline and arterial, venous and tardive phases), identifying the most reliable and also exploring the underlying temporal trend of these values. Materials and Methods: Eleven patients who underwent DECT examination and were characterized by low liver fat content were included in this retrospective study. By using the Syngo.via Frontier–DE IronVNC tool, regions of interest (ROI) were placed on the VIC images at 3 hepatic levels, both in left and right liver lobes, at each DECT time point. Friedman’s test followed by Bonferroni-adjusted Wilcoxon signed-rank test for post-hoc analysis was performed to assess differences between DECT timepoints. Page’s L test was performed to test the temporal trend of VIC across the 4 examined timepoints. Results: For both liver lobes, Friedman’s test followed by Bonferroni-adjusted Wilcoxon signed-rank test revealed that VIC values differed significantly when extracted from ROIs placed at the 4 different timepoints. The Page’s L test for multiple comparison revealed a significant growing trend for VIC, from baseline acquisition to the fourth and last time point post-contrast agent injection. Conclusions: The extraction of hepatic VIC in healthy subjects was found to be significantly influenced by the DECT time point chosen for the extrapolation of the VIC values.
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Cruz-Hernández E, Mahmood U, Golia Pernicka JS, Paroder V, Petkovska I, Gollub MJ, Shia J, Ganesh K, Bates DDB. Initial evaluation of dual-energy computed tomography as an imaging biomarker for hepatic metastases from neuroendocrine tumor of the gastrointestinal tract. Quant Imaging Med Surg 2021; 11:2085-2092. [PMID: 33936989 DOI: 10.21037/qims-20-917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background To evaluate quantitative iodine parameters from the arterial phase dual-energy computed tomography (DECT) scans as an imaging biomarker for tumor grade (TG), mitotic index (MI), and Ki-67 proliferation index of hepatic metastases from neuroendocrine tumors (NETs) of the gastrointestinal (GI) tract. Imaging biomarkers have the potential to provide relevant clinical information about pathologic processes beyond lesion morphology. NETs are a group of rare, heterogeneous neoplasms classified by World Health Organization (WHO) TG, which is derived from MI and Ki-67 proliferation index. Imaging biomarkers for these pathologic features and TG may be useful. Methods Between January 2014 and April 2019, 73 unique patients with hepatic metastases from NET of the GI tract underwent DECT of the abdomen with an arterial phase were analyzed after exclusions. Using GSIViewer software (GE Healthcare, Madison, Wisconsin), elliptical regions of interest (ROIs) were placed over selected hepatic metastases by a fellowship trained abdominal radiologist. Quantitative iodine concentration (IC) data was extracted from the lesion ROIs, and the normalized IC (lesion IC/aorta IC) and relative IC (lesion IC/liver IC) for each liver were calculated. Spearman correlation was calculated for lesion mean IC, normalized IC, and relative IC to both Ki-67 proliferation and mitotic indices. Student's t-test was performed to compare lesion mean IC, normalized IC and relative IC between WHO TGs. Results There was very weak correlation between both normalized IC and relative IC for both Ki-67 proliferation and mitotic indices. A significant difference was not observed between normalized IC and relative IC to distinguish metastases from G1 and G2/3 tumors. Conclusions Our study finds limited potential for quantitative parameters from DECT to distinguish neuroendocrine hepatic metastases by WHO TG, as well as limited potential as an imaging biomarker for Ki-67 proliferation and mitotic indices in this setting. Our findings of a lack of correlation between Ki-67 and quantitative iodine parameters stands in contrast to existing literature that reports positive correlations for these parameters in the rectum and stomach.
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Affiliation(s)
| | - Usman Mahmood
- Department of Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - Viktoriya Paroder
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Iva Petkovska
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Marc J Gollub
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jinru Shia
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Karuna Ganesh
- Molecular Pharmacology Program and Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - David D B Bates
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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Dual-energy computed tomography image-based volumetric-modulated arc therapy planning for reducing the effect of contrast-enhanced agent on dose distributions. Med Dosim 2021; 46:328-334. [PMID: 33931321 DOI: 10.1016/j.meddos.2021.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/01/2021] [Accepted: 03/19/2021] [Indexed: 11/20/2022]
Abstract
To compare the effect of a contrast-enhanced (CE) agent on volumetric-modulated arc therapy plans based on four types of images-virtual monochromatic images (VMIs) captured at 70 and 140 keV (namely VMI70 and VMI140, respectively), water density image (WDI), and virtual non-contrast image (VNC) generated using a dual-energy computed tomography (DECT) system. A tissue characterization phantom and a multi-energy phantom were scanned, and VMI70, VMI140, WDI, and VNC were retrospectively reconstructed. For each image, a lookup table (LUT) was created. For 13 patients with nasopharyngeal cancer, non-CE and CE scans were performed, and volumetric-modulated arc therapy plans were generated on the basis of non-CE VMI70. Subsequently, the doses were re-calculated using the four types of DECT images and their corresponding LUTs. The maximum differences in the physical density estimation were 21.3, 5.2, -3.9, and 0.5% for VMI70, VMI140, WDI, and VNC, respectively. Compared with VMI70, the WDI approach significantly reduced (p < 0.05) the dosimetric difference due to the CE agent for the planning target volume (PTV) (D50%), whereas the difference was significantly increased for D1%. Except for PTV (D1%), the differences were significantly lower (p < 0.05) in the treatment plans based on VMI140 and VNC than that based on VMI70. For the VNC, the mean difference was less than 0.2% for all dosimetric parameters for the PTV. For patients with NPC, treatment plans based on the VNC derived from CE scan showed the best agreement with those based on the non-CE VMI70. Ideally, the effect of CE agent on dose distribution does not appear in treatment planning procedures.
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Impact of dose reduction and the use of an advanced model-based iterative reconstruction algorithm on spectral performance of a dual-source CT system: A task-based image quality assessment. Diagn Interv Imaging 2021; 102:405-412. [PMID: 33820752 DOI: 10.1016/j.diii.2021.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 01/14/2023]
Abstract
PURPOSE To assess the impact of dose reduction and the use of an advanced modeled iterative reconstruction algorithm (ADMIRE) on image quality in low-energy monochromatic images from a dual-source dual energy computed tomography CT (DSCT) platform. MATERIALS AND METHODS Acquisitions on an image-quality phantom were performed using DSCT equipment with 100/Sn150 kVp for four dose levels (CTDIvol: 20/11/8/5mGy). Raw data were reconstructed for six energy levels (40/50/60/70/80/100 keV) using filtered back projection and two levels of ADMIRE (A3/A5). Noise power spectrum (NPS) and task-based transfer function (TTF) were calculated on virtual monoenergetic images (VMIs). Detectability index (d') was computed to model the detection task of two enhanced iodine lesions as function of keV. RESULTS Noise-magnitude was significantly reduced between 40 to 70 keV by -56±0% (SD) (range: -56%--55%) with FBP; -56±0% (SD) (-56%--56%) with A3; and -57±1% (SD) (range: -57%--56%) with A5. The average spatial frequency of the NPS peaked at 70 keV and decreased as ADMIRE level increased. TTF values at 50% were greatest at 40 keV and shifted towards lower frequencies as the keV increased. The detectability of both lesions increased with increasing dose level and ADMIRE level. For the simulated lesion with iodine at 2mg/mL, d' values peaked at 70 keV for all reconstruction types, except for A3 at 20 mGy and A5 at 11 and 20 mGy, where d' peaked at 60 keV. For the other simulated lesion, d' values were highest at 40 keV and decreased beyond. CONCLUSION At low keV on VMIs, this study confirms that iterative reconstruction reduces the noise magnitude, improves the spatial resolution and increases the detectability of enhanced iodine lesions.
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Siegel MJ, Bhalla S, Cullinane M. Dual-Energy CT Material Decomposition in Pediatric Thoracic Oncology. Radiol Imaging Cancer 2021; 3:e200097. [PMID: 33778757 DOI: 10.1148/rycan.2021200097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/22/2020] [Accepted: 08/27/2020] [Indexed: 11/11/2022]
Abstract
Technical advances in CT have enabled implementation of dual-energy CT into routine clinical practice. By acquiring images at two different energy spectra, dual-energy CT enables material decomposition, allowing generation of material- and energy-specific images. Material-specific images include virtual nonenhanced images and iodine-specific images (iodine maps). Energy-specific images include virtual monoenergetic images. The reconstructed images can provide unique qualitative and quantitative information about tissue composition and contrast media distribution. In thoracic oncologic imaging, dual-energy CT provides advantages in characterization of thoracic malignancies and lung nodules, determination of extent of disease, and assessment of response to therapy. An especially important feature in children is that dual-energy CT does not come at a higher radiation exposure. Keywords: CT, CT-Quantitative, Lung, Mediastinum, Neoplasms-Primary, Pediatrics, Thorax, Treatment Effects © RSNA, 2021.
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Affiliation(s)
- Marilyn J Siegel
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd, St Louis, MO 63110 (M.J.S., S.B.); and Siemens Healthineers, Malvern, Pa (M.C.)
| | - Sanjeev Bhalla
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd, St Louis, MO 63110 (M.J.S., S.B.); and Siemens Healthineers, Malvern, Pa (M.C.)
| | - Mike Cullinane
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd, St Louis, MO 63110 (M.J.S., S.B.); and Siemens Healthineers, Malvern, Pa (M.C.)
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Shapira N, Mei K, Noël PB. Spectral CT quantification stability and accuracy for pediatric patients: A phantom study. J Appl Clin Med Phys 2021; 22:16-26. [PMID: 33426801 PMCID: PMC7984483 DOI: 10.1002/acm2.13161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/08/2020] [Accepted: 12/16/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Spectral computed tomography (spectral CT) provides access to clinically relevant measures of endogenous and exogenous materials in patients. For pediatric patients, current spectral CT applications include lesion characterization, quantitative vascular imaging, assessments of tumor response to treatment, and more. OBJECTIVE The aim of this study is a comprehensive investigation of the accuracy and stability of spectral quantifications from a spectral detector-based CT system with respect to different patient sizes and radiation dose levels relevant for the pediatric population. MATERIALS AND METHODS A spectral CT phantom with tissue-mimicking materials and iodine concentrations relevant for pediatric imaging was scanned on a spectral detector CT system using a standard pediatric abdominal protocol at 100%, 67%, 33% and 10% of the nominal radiation dose level. Different pediatric patient sizes were simulated using supplemental 3D-printed extension rings. Virtual mono-energetic, iodine density, effective atomic number, and electron density results were analyzed for stability with respect to radiation dose and patient size. RESULTS Compared to conventional CT imaging, a pronounced improvement in the stability of attenuation measurements across patient size was observed when using virtual mono-energetic images. Iodine densities were within 0.1 mg/ml, effective atomic numbers were within 0.26 atomic numbers and electron density quantifications were within ±1.0% of their respective nominal values. Relative to the nominal dose clinical protocol, differences in attenuation of all tissue-mimicking materials were maintained below 1.6 HU for a 33% dose reduction, below 2.7 HU for a 67% dose reduction and below 3.7 HU for a 90% dose reduction, for all virtual mono-energetic energies equal to or greater than 50 keV. Iodine, and effective atomic number quantifications were stable to within 0.1 mg/ml and 0.06 atomic numbers, respectively, across all measured dose levels. CONCLUSION Spectral CT provides accurate and stable material quantification with respect to radiation dose reduction (up to 90%) and differing pediatric patient size. The observed consistency is an important step towards quantitative pediatric imaging at low radiation exposure levels.
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Affiliation(s)
- Nadav Shapira
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaUSA
| | - Kai Mei
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaUSA
| | - Peter B. Noël
- Department of RadiologyUniversity of PennsylvaniaPhiladelphiaUSA
- Department of Diagnostic and Interventional RadiologyTechnical University of MunichMunichGermany
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Sellerer T, Mechlem K, Tang R, Taphorn KA, Pfeiffer F, Herzen J. Dual-Energy X-Ray Dark-Field Material Decomposition. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:974-985. [PMID: 33290214 DOI: 10.1109/tmi.2020.3043303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Dual-energy imaging is a clinically well-established technique that offers several advantages over conventional X-ray imaging. By performing measurements with two distinct X-ray spectra, differences in energy-dependent attenuation are exploited to obtain material-specific information. This information is used in various imaging applications to improve clinical diagnosis. In recent years, grating-based X-ray dark-field imaging has received increasing attention in the imaging community. The X-ray dark-field signal originates from ultra small-angle scattering within an object and thus provides information about the microstructure far below the spatial resolution of the imaging system. This property has led to a number of promising future imaging applications that are currently being investigated. However, different microstructures can hardly be distinguished with current X-ray dark-field imaging techniques, since the detected dark-field signal only represents the total amount of ultra small-angle scattering. To overcome these limitations, we present a novel concept called dual-energy X-ray dark-field material decomposition, which transfers the basic material decomposition approach from attenuation-based dual-energy imaging to the dark-field imaging modality. We develop a physical model and algorithms for dual-energy dark-field material decomposition and evaluate the proposed concept in experimental measurements. Our results suggest that by sampling the energy-dependent dark-field signal with two different X-ray spectra, a decomposition into two different microstructured materials is possible. Similar to dual-energy imaging, the additional microstructure-specific information could be useful for clinical diagnosis.
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Paganetti H, Beltran C, Both S, Dong L, Flanz J, Furutani K, Grassberger C, Grosshans DR, Knopf AC, Langendijk JA, Nystrom H, Parodi K, Raaymakers BW, Richter C, Sawakuchi GO, Schippers M, Shaitelman SF, Teo BKK, Unkelbach J, Wohlfahrt P, Lomax T. Roadmap: proton therapy physics and biology. Phys Med Biol 2021; 66. [DOI: 10.1088/1361-6560/abcd16] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022]
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Papadakis AE, Damilakis J. Technical Note: Quality assessment of virtual monochromatic spectral images on a dual energy CT scanner. Phys Med 2021; 82:114-121. [DOI: 10.1016/j.ejmp.2021.01.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/26/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022] Open
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Laukamp KR, Tirumani SH, Lennartz S, Hokamp NG, Gupta A, Pennig L, Persigehl T, Gilkeson R, Ramaiya N. Evaluation of equivocal small cystic pancreatic lesions with spectral-detector computed tomography. Acta Radiol 2021; 62:172-181. [PMID: 32306744 DOI: 10.1177/0284185120917119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Evaluation of small cystic lesions of the pancreas remains a challenging task, as due to their size appearance can be rather hypodense than clearly fluid-filled. PURPOSE To evaluate whether additional information provided by novel dual-layer spectral-detector computed tomography (SDCT) imaging can improve assessment of these lesions. MATERIAL AND METHODS For this retrospective study, we reviewed reports of 1192 contrast-enhanced portal-venous phase SDCT scans of the abdomen conducted between May 2017 and January 2019. On basis of the radiological report 25 small (≤1.5 cm) cystic pancreatic lesions in 22 patients were identified, in which additional short-term follow-up imaging was recommended to confirm/clarify cystic nature. Conventional images (CI) and spectral images (SI) including virtual-monoenergetic images at 40 keV (VMI), iodine-density and iodine-overlay images were reconstructed. Two readers indicated lesion conspicuity and confidence for presence of cystic nature on three-point scales. First, solely CI were evaluated, while in a second reading after a four-week interval, the combination of CI and corresponding SI were reviewed. Quantitatively, ROI-based mean attenuation was measured in CI and VMI. RESULTS In the subjective reading, SI significantly improved lesion conspicuity (CI 2 [1-2], SI 3 [2-3], P < 0.001) and confidence regarding presence of cystic nature (CI 2 [1-2], SI 3 [3-3], P < 0.001). Inter-observer agreement depicted by intraclass correlation coefficient improved considerably from 0.51 with only CI to 0.85 when the combination with SI was used. Further, VMI displayed significantly higher signal-to-noise (CI 1.2 ± 0.8, VMI 3.2 ± 1.8, P < 0.001) and contrast-to-noise ratios (CI 2.6 ± 0.8, VMI 4.7 ± 1.9). CONCLUSION Compared to CI alone, combination with SI significantly improves visualization and confidence in evaluation of small equivocal cystic pancreatic lesions.
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Affiliation(s)
- Kai Roman Laukamp
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Sree Harsha Tirumani
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
| | - Simon Lennartz
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Nils Große Hokamp
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Amit Gupta
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
| | - Lenhard Pennig
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Thorsten Persigehl
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Robert Gilkeson
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
| | - Nikhil Ramaiya
- Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
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Evaluation of Spatial Resolution of Virtual Monochromatic Imaging In Vitro: Effect of Energy Level and Contrast. J Comput Assist Tomogr 2021; 45:93-97. [PMID: 32976256 DOI: 10.1097/rct.0000000000001046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Our aim was to evaluate effects of the energy level and contrast on the spatial resolution of virtual monochromatic imaging (VMI). METHODS With 2 types of computed tomographic (CT) scanners (Discovery CT750 HD and Revolution CT), we scanned an elliptical cylinder acrylic phantom with 20- or 40-fold dilutions of contrast medium and obtained VMI data sets at 40, 50, 60, and 70 keV. We evaluated the effects of energy levels and contrast on modulation transfer function (MTF) and the effect of energy levels on noise power spectra (NPS). RESULTS With both CT scanners, MTF decreased significantly as the energy level decreased. The effect of the dilution of contrast media on MTF varied with CT scanners. With both scanners, NPS curves demonstrate uniform increase in NPS across the entire spatial frequency as the energy levels decreased. CONCLUSIONS The energy level and contrast can affect the spatial resolution of VMIs.
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Greffier J, Si-Mohamed S, Dabli D, de Forges H, Hamard A, Douek P, Beregi JP, Frandon J. Performance of four dual-energy CT platforms for abdominal imaging: a task-based image quality assessment based on phantom data. Eur Radiol 2021; 31:5324-5334. [PMID: 33449188 DOI: 10.1007/s00330-020-07671-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 12/08/2020] [Accepted: 12/23/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVES To compare the spectral performance of dual-energy CT (DECT) platforms using task-based image quality assessment based on phantom data. MATERIALS AND METHODS Two CT phantoms were scanned on four DECT platforms: fast kV-switching CT (KVSCT), split filter CT (SFCT), dual-source CT (DSCT), and dual-layer CT (DLCT). Acquisitions on each phantom were performed using classical parameters of abdomen-pelvic examination and a CTDIvol at 10 mGy. Noise power spectrum (NPS) and task-based transfer function (TTF) were evaluated from 40 to 140 keV of virtual monoenergetic images. A detectability index (d') was computed to model the detection task of two contrast-enhanced lesions as function of keV. RESULTS The noise magnitude decreased from 40 to 70 keV for all DECT platforms, and the highest noise magnitude values were found for KVSCT and SFCT and the lowest for DSCT and DLCT. The average NPS spatial frequency shifted towards lower frequencies as the energy level increased for all DECT platforms, smoothing the image texture. TTF values decreased with the increase of keV deteriorating the spatial resolution. For both simulated lesions, higher detectability (d' value) was obtained at 40 keV for DLCT, DSCT, and SFCT but at 70 keV for KVSCT. The detectability of both simulated lesions was highest for DLCT and DSCT. CONCLUSION Highest detectability was found for DLCT for the lowest energy levels. The task-based image quality assessment used for the first time for DECT acquisitions showed the benefit of using low keV for the detection of contrast-enhanced lesions. KEY POINTS • Detectability of both simulated contrast-enhanced lesions was higher for dual-layer CT for the lowest energy levels. • The image noise increased and the image texture changed for the lowest energy levels. • The detectability of both simulated contrast-enhanced lesions was highest at 40 keV for all dual-energy CT platforms except for fast kV-switching platform.
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Affiliation(s)
- J Greffier
- Department of Medical Imaging, CHU Nimes, Medical Imaging Group Nimes, EA 2415, Univ Montpellier, Bd Prof Robert Debré, 30029, Nîmes Cedex 9, France.
| | - S Si-Mohamed
- Department of Radiology, Hospices Civils de Lyon, 69500, Lyon, France.,INSA-Lyon, Université Lyon, Université Claude-Bernard Lyon 1, UJM-Saint-Étienne, CNRS, Inserm, CREATIS UMR 5220, U1206, 69621, Lyon, France
| | - D Dabli
- Department of Medical Imaging, CHU Nimes, Medical Imaging Group Nimes, EA 2415, Univ Montpellier, Bd Prof Robert Debré, 30029, Nîmes Cedex 9, France
| | - H de Forges
- Department of Medical Imaging, CHU Nimes, Medical Imaging Group Nimes, EA 2415, Univ Montpellier, Bd Prof Robert Debré, 30029, Nîmes Cedex 9, France
| | - A Hamard
- Department of Medical Imaging, CHU Nimes, Medical Imaging Group Nimes, EA 2415, Univ Montpellier, Bd Prof Robert Debré, 30029, Nîmes Cedex 9, France
| | - P Douek
- Department of Radiology, Hospices Civils de Lyon, 69500, Lyon, France.,INSA-Lyon, Université Lyon, Université Claude-Bernard Lyon 1, UJM-Saint-Étienne, CNRS, Inserm, CREATIS UMR 5220, U1206, 69621, Lyon, France
| | - J P Beregi
- Department of Medical Imaging, CHU Nimes, Medical Imaging Group Nimes, EA 2415, Univ Montpellier, Bd Prof Robert Debré, 30029, Nîmes Cedex 9, France
| | - J Frandon
- Department of Medical Imaging, CHU Nimes, Medical Imaging Group Nimes, EA 2415, Univ Montpellier, Bd Prof Robert Debré, 30029, Nîmes Cedex 9, France
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Wang L, Zhang Y, Chen Y, Tan J, Wang L, Zhang J, Yang C, Ma Q, Ge Y, Xu Z, Pan Z, Du L, Yan F, Yao W, Zhang H. The Performance of a Dual-Energy CT Derived Radiomics Model in Differentiating Serosal Invasion for Advanced Gastric Cancer Patients After Neoadjuvant Chemotherapy: Iodine Map Combined With 120-kV Equivalent Mixed Images. Front Oncol 2021; 10:562945. [PMID: 33585186 PMCID: PMC7874026 DOI: 10.3389/fonc.2020.562945] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 11/23/2020] [Indexed: 12/26/2022] Open
Abstract
Objectives The aim was to determine whether the dual-energy CT radiomics model derived from an iodine map (IM) has incremental diagnostic value for the model based on 120-kV equivalent mixed images (120 kVp) in preoperative restaging of serosal invasion with locally advanced gastric cancer (LAGC) after neoadjuvant chemotherapy (NAC). Methods A total of 155 patients (110 in the training cohort and 45 in the testing cohort) with LAGC who had standard NAC before surgery were retrospectively enrolled. All CT images were analyzed by two radiologists for manual classification. Volumes of interests (VOIs) were delineated semi-automatically, and 1,226 radiomics features were extracted from every segmented lesion in both IM and 120 kVp images, respectively. Spearman's correlation analysis and the least absolute shrinkage and selection operator (LASSO) penalized logistic regression were implemented for filtering unstable and redundant features and screening out vital features. Two predictive models (120 kVp and IM-120 kVp) based on 120 kVp selected features only and 120 kVp combined with IM selected features were established by multivariate logistic regression analysis. We then build a combination model (ComModel) developed with IM-120 kVp signature and ycT. The performance of these three models and manual classification were evaluated and compared. Result Three radiomics models showed great predictive accuracy and performance in both the training and testing cohorts (ComModel: AUC: training, 0.953, testing, 0.914; IM-120 kVp: AUC: training, 0.953, testing, 0.879; 120 kVp: AUC: training, 0.940, testing, 0.831). All these models showed higher diagnostic accuracy (ComModel: 88.9%, IM-120 kVp: 84.4%, 120 kVp: 80.0%) than manual classification (68.9%) in the testing group. ComModel and IM-120 kVp model had better performances than manual classification both in the training (both p<0.001) and testing cohorts (p<0.001 and p=0.034, respectively). Conclusions Dual-energy CT-based radiomics models demonstrated convincible diagnostic performance in differentiating serosal invasion in preoperative restaging for LAGC. The radiomics features derived from IM showed great potential for improving the diagnostic capability.
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Affiliation(s)
- Lingyun Wang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yang Zhang
- Department of Radiology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Yong Chen
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jingwen Tan
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lan Wang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Zhang
- Department of Oncology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chunxue Yang
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qianchen Ma
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yingqian Ge
- CHN DI CT Collaboration, Siemens Healthineers Ltd, Shanghai, China
| | - Zhihan Xu
- CHN DI CT Collaboration, Siemens Healthineers Ltd, Shanghai, China
| | - Zilai Pan
- Department of Radiology, Ruijin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lianjun Du
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fuhua Yan
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weiwu Yao
- Department of Radiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huan Zhang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Gentili F, Guerrini S, Mazzei FG, Monteleone I, Di Meglio N, Sansotta L, Perrella A, Puglisi S, De Filippo M, Gennaro P, Volterrani L, Castagna MG, Dotta F, Mazzei MA. Dual energy CT in gland tumors: a comprehensive narrative review and differential diagnosis. Gland Surg 2020; 9:2269-2282. [PMID: 33447579 DOI: 10.21037/gs-20-543] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dual energy CT (DECT)with image acquisition at two different photon X-ray levels allows the characterization of a specific tissue or material/elements, the extrapolation of virtual unenhanced and monoenergetic images, and the quantification of iodine uptake; such special capabilities make the DECT the perfect technique to support oncological imaging for tumor detection and characterization and treatment monitoring, while concurrently reducing the dose of radiation and iodine and improving the metal artifact reduction. Even though its potential in the field of oncology has not been fully explored yet, DECT is already widely used today thanks to the availability of different CT technologies, such as dual-source, single-source rapid-switching, single-source sequential, single-source twin-beam and dual-layer technologies. Moreover DECT technology represents the future of the imaging innovation and it is subject to ongoing development that increase according its clinical potentiality, in particular in the field of oncology. This review points out recent state-of-the-art in DECT applications in gland tumors, with special focus on its potential uses in the field of oncological imaging of endocrine and exocrine glands.
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Affiliation(s)
- Francesco Gentili
- Unit of Diagnostic Imaging, Department of Radiological Sciences, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Susanna Guerrini
- Unit of Diagnostic Imaging, Department of Radiological Sciences, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Francesco Giuseppe Mazzei
- Unit of Diagnostic Imaging, Department of Radiological Sciences, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Ilaria Monteleone
- Unit of Diagnostic Imaging, Department of Medical, Surgical and Neuro Sciences and of Radiological Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Nunzia Di Meglio
- Unit of Diagnostic Imaging, Department of Medical, Surgical and Neuro Sciences and of Radiological Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Letizia Sansotta
- Unit of Diagnostic Imaging, Department of Medical, Surgical and Neuro Sciences and of Radiological Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Armando Perrella
- Unit of Diagnostic Imaging, Department of Medical, Surgical and Neuro Sciences and of Radiological Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Sara Puglisi
- Unit of Radiology, Department of Medicine and Surgery, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy
| | - Massimo De Filippo
- Unit of Radiology, Department of Medicine and Surgery, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy
| | - Paolo Gennaro
- Department of Maxillofacial Surgery, University of Siena, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Luca Volterrani
- Unit of Diagnostic Imaging, Department of Medical, Surgical and Neuro Sciences and of Radiological Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Maria Grazia Castagna
- Unit of Endocrinology, Department of Medical, Surgical and Neuro Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Francesco Dotta
- Unit of Diabetology, Department of Medical, Surgical and Neuro Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Maria Antonietta Mazzei
- Unit of Diagnostic Imaging, Department of Medical, Surgical and Neuro Sciences and of Radiological Sciences, University of Siena, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
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Therapeutic response assessment in pancreatic ductal adenocarcinoma: society of abdominal radiology review paper on the role of morphological and functional imaging techniques. Abdom Radiol (NY) 2020; 45:4273-4289. [PMID: 32936417 DOI: 10.1007/s00261-020-02723-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/17/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related death in the United States and is projected to be the second by 2030. Systemic combination chemotherapy is considered an essential first-line treatment for the majority of patients with PDA, in both the neoadjuvant and palliative settings. In addition, a number of novel therapies are being tested in clinical trials for patients with advanced PDA. In all cases, accurate and timely assessment of treatment response is critical to guide therapy, reduce drug toxicities and cost from a failing therapy, and aid adaptive clinical trials. Conventional morphological imaging has significant limitations, especially in the context of determining primary tumor response and resectability following neoadjuvant therapies. In this article, we provide an overview of current therapy options for PDA, highlight several morphological imaging findings that may be helpful to reduce over-staging following neoadjuvant therapy, and discuss a number of emerging imaging, and non-imaging, tools that have shown promise in providing a more precise quantification of disease burden and treatment response in PDA.
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El Kayal N, Mohallel A, Maintz D, Eid M, Emara DM. Improved detectability of hypoattenuating focal pancreatic lesions by dual-layer computed tomography using virtual monoenergetic images. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2020. [DOI: 10.1186/s43055-020-00270-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Multidetector CT is the mainstay for radiologic evaluation of pancreatic pathology. Still, imaging of focal pancreatic lesions using MDCT is faced by a number of challenges that are related to the limited contrast between the lesion and surrounding parenchyma, such as detecting early-stage pancreatic cancer and subtle features of cystic lesions that point to malignancy. Dual-layer CT is the first dual-energy CT machine based on separation of high- and low-energy photons at the detector level. If improved contrast between the lesions and normal pancreatic parenchyma could be achieved on CT images, we may expect enhanced CT detection of pancreatic lesions. The purpose of this study was to evaluate whether virtual monoenergetic reconstructions generated using contrast-enhanced dual-layer CT could improve detectability of hypoattenuating focal pancreatic lesions compared to conventional polyenergetic reconstructions.
Results
Fifty-four lesions were identified and verified by histopathology or follow-up CT, MRCP, and/or EUS along with clinical data. Across the virtual monoenergetic spectrum, 40 KeV images had the highest contrast-to-noise and signal-to-noise ratios (p < 0.001, p < 0.001) and were significantly higher than conventional images (p < 0.001). Subjective scores for lesion visibility at low kiloelectron volt monoenergetic (40 and 50 KeV) images greatly exceeded conventional images (p < 0.001).
Conclusion
Low kiloelectron volt monoenergetic reconstructions of contrast-enhanced dual-layer CT significantly improve detectability of hypoattenuating focal pancreatic lesions compared to conventional polyenergetic reconstructions.
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Sauter AP, Ostmeier S, Nadjiri J, Deniffel D, Rummeny EJ, Pfeiffer D. Iodine concentration of healthy lymph nodes of neck, axilla, and groin in dual-energy computed tomography. Acta Radiol 2020; 61:1505-1511. [PMID: 32064891 DOI: 10.1177/0284185120903448] [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] [Indexed: 12/18/2022]
Abstract
BACKGROUND Lymph nodes (LN) are examined in every computed tomography (CT) scan. Until now, an evaluation is only possible based on morphological criteria. With dual-energy CT (DECT) systems, iodine concentration (IC) can be measured which could conduct in an improved diagnostic evaluation of LNs. PURPOSE To define standard values for IC of cervical, axillary, and inguinal LNs in DECT. MATERIAL AND METHODS Imaging data of 297 patients who received a DECT scan of the neck, thorax, abdomen-pelvis, or a combination of those in a portal-venous phase were retrospectively collected from the institutional PACS. No present history of malignancy, inflammation, or trauma in the examined region was present. For each examined region, the data of 99 patients were used. The IC of the three largest LNs, the main artery, the main vein, and a local muscle of the examined area was measured, respectively. RESULTS Normalization of the IC of LNs to the artery, vein, muscle, or a combination of those did not lead to a decreased value-range. The smallest range and confidence interval (CI) of IC was found when using absolute values of IC for each region. Hereby, mean values (95% CI) for IC of LN were found: 2.09 mg/mL (2.00-2.18 mg/mL) for neck, 1.24 mg/mL (1.16-1.33 mg/mL) for axilla, and 1.11 mg/mL (1.04-1.17 mg/mL) for groin. CONCLUSION The present study suggests standard values for IC of LNs in dual-layer CT could be used to differentiate between healthy and pathological lymph nodes, considering the used contrast injection protocol.
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Affiliation(s)
- Andreas P Sauter
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Sophie Ostmeier
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Jonathan Nadjiri
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Dominik Deniffel
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Ernst J Rummeny
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Daniela Pfeiffer
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
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Huang WH, Jhan KJ, Yang CC. Investigating the feasibility of generating dual-energy CT from one 120-kVp CT scan: a phantom study. J Appl Clin Med Phys 2020; 22:126-137. [PMID: 33426800 PMCID: PMC7882117 DOI: 10.1002/acm2.13148] [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: 08/26/2020] [Revised: 11/30/2020] [Accepted: 12/08/2020] [Indexed: 11/17/2022] Open
Abstract
Introduction This study aimed to investigate the feasibility of generating pseudo dual‐energy CT (DECT) from one 120‐kVp CT by using convolutional neural network (CNN) to derive additional information for quantitative image analysis through phantom study. Methods Dual‐energy scans (80/140 kVp) and single‐energy scans (120 kVp) were performed for five calibration phantoms and two evaluation phantoms on a dual‐source DECT scanner. The calibration phantoms were used to generate training dataset for CNN optimization, while the evaluation phantoms were used to generate testing dataset. A CNN model which takes 120‐kVp images as input and creates 80/140‐kVp images as output was built, trained, and tested by using Caffe CNN platform. An in‐house software to quantify contrast enhancement and synthesize virtual monochromatic CT (VMCT) for CNN‐generated pseudo DECT was implemented and evaluated. Results The CT numbers in 80‐kVp pseudo images generated by CNN are differed from the truth by 11.57, 16.67, 13.92, 12.23, 10.69 HU for syringes filled with iodine concentration of 2.19, 4.38, 8.75, 17.5, 35 mg/ml, respectively. The corresponding results for 140‐kVp CT are 3.09, 9.10, 7.08, 9.81, 7.59 HU. The estimates of iodine concentration calculated based on the proposed method are differed from the truth by 0.104, 0.603, 0.478, 0.698, 0.795 mg/ml for syringes filled with iodine concentration of 2.19, 4.38, 8.75, 17.5, 35 mg/ml, respectively. With regards to image quality enhancement, VMCT synthesized by using pseudo DECT shows the best contrast‐to‐noise ratio at 40 keV. Conclusion In conclusion, the proposed method should be a practicable strategy for iodine quantification in contrast enhanced 120‐kVp CT without using specific scanner or scanning procedure.
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Affiliation(s)
- Wen-Hui Huang
- Department of Radiology, Mackay Memorial Hospital, Taipei, Taiwan.,Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Kai-Jie Jhan
- Department of Nuclear Medicine, National Taiwan University Cancer Center, Taipei, Taiwan
| | - Ching-Ching Yang
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Medical Research, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan
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Skornitzke S, Kauczor HU, Stiller W. Virtual monoenergetic reconstructions of dynamic DECT acquisitions for calculation of perfusion maps of blood flow: Quantitative comparison to conventional, dynamic 80 kV p CT perfusion. Eur J Radiol 2020; 131:109262. [PMID: 32942200 DOI: 10.1016/j.ejrad.2020.109262] [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: 02/26/2020] [Revised: 07/09/2020] [Accepted: 08/27/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE Investigation of potential improvements in dynamic CT perfusion measurements by exploitation of improved visualization of contrast agent in virtual monoenergetic reconstructions of images acquired with dual-energy computed tomography (DECT). METHOD For 17 patients with pancreatic carcinoma, dynamic dual-source DECT acquisitions were performed at 80kVp/Sn140kVp every 1.5 s over 51 s. Virtual monoenergetic images (VMI) were reconstructed for photon energies between 40 keV and 150 keV (5 keV steps). Using the maximum-slope model, perfusion maps of blood flow were calculated from VMIs and 80kVp images and compared quantitatively with regard to blood flow measured in regions of interest in healthy tissue and carcinoma, standard deviation (SD), and absolute-difference-to-standard-deviation ratio (ADSDR) of measurements. RESULTS On average, blood flow calculated from VMIs increased with increasing energy levels from 114.3 ± 37.2 mL/100 mL/min (healthy tissue) and 45.6 ± 25.3 mL/100 mL/min (carcinoma) for 40 keV to 128.6 ± 58.9 mL/100 mL/min (healthy tissue) and 75.5 ± 49.8 mL/100 mL/min (carcinoma) for 150 keV, compared to 114.2 ± 37.4 mL/100 mL/min (healthy tissue) and 46.5 ± 26.6 mL/100 mL/min (carcinoma) for polyenergetic 80kVp. Differences in blood flow between tissue types were significant for all energies. Differences between perfusion maps calculated from VMIs and 80kVp images were not significant below 110 keV. SD and ADSDR were significantly better for perfusion maps calculated from VMIs at energies between 40 keV and 55 keV than for those calculated from 80kVp images. Compared to effective dose of dynamic 80kVp acquisitions (4.6 ± 2.2mSv), dose of dynamic DECT/VMI acquisitions (8.0 ± 3.7mSv) was higher. CONCLUSIONS Perfusion maps of blood flow based on low-energy VMIs between 40 keV and 55 keV offer improved robustness and quality of quantitative measurements over those calculated from 80kVp image data (reference standard), albeit at increased patient radiation exposure.
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Affiliation(s)
- Stephan Skornitzke
- Diagnostic and Interventional Radiology (DIR), Heidelberg University Hospital, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany.
| | - Hans-Ulrich Kauczor
- Diagnostic and Interventional Radiology (DIR), Heidelberg University Hospital, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany.
| | - Wolfram Stiller
- Diagnostic and Interventional Radiology (DIR), Heidelberg University Hospital, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany.
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Sauter AP, Kössinger A, Beck S, Deniffel D, Dapper H, Combs SE, Rummeny EJ, Pfeiffer D. Dual-energy CT parameters in correlation to MRI-based apparent diffusion coefficient: evaluation in rectal cancer after radiochemotherapy. Acta Radiol Open 2020; 9:2058460120945316. [PMID: 32995044 PMCID: PMC7503032 DOI: 10.1177/2058460120945316] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/03/2020] [Indexed: 01/04/2023] Open
Abstract
Background Rectal cancer (RC) is a frequent malignancy for which magnetic resonance imaging (MRI) is the most common and accurate imaging. Iodine concentration (IC) can be quantified with spectral dual-layer computed tomography CT (DL-CT), which could improve imaging of RC, especially for evaluation of response to radiochemotherapy (RCT). Purpose To compare a DL-CT system to MRI as the non-invasive imaging gold standard for imaging of RC to evaluate the possibility of a response evaluation with DL-CT. Material and Methods Eleven patients who received DL-CT as well as MRI before and after RCT of RC were retrospectively included into this study. For each examination, a region of interest (ROI) was placed within the tumor. For MRI, the mean apparent diffusion coefficient (ADC) was assessed. For DL-CT, IC, z-effective, and Hounsfield Units (HU) were measured. IC, z-effective, and HU were normalized to the aorta. ADC was correlated to absolute and relative normalized IC, z-effective, and HU with Spearman’s ρ. Differences before and after treatment were tested with Wilcoxon signed-rank test. Results HU, IC, and Z-effective values in DL-CT images decreased significantly after RCT (P<0.01 for each comparison). The mean ADC increased significantly after RCT. Spearman’s ρ of the absolute IC difference and the absolute ADC (both before and after RCT) is high and significant (ρ = 0.73; P = 0.01), whereas the ρ-value for z-effective (ρ = 0.56) or HU (ρ = 0.45) to ADC was lower and non-significant. Conclusion Response evaluation of RC after RCT could be possible with DL-CT via the measurement of IC.
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Affiliation(s)
- Andreas P Sauter
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
| | - Antonia Kössinger
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
| | - Stefanie Beck
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
| | - Dominik Deniffel
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
| | - Hendrik Dapper
- Department of Radiation Oncology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany.,Department of Radiation Sciences (DRS), Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany.,Deutsches Konsortium für Translationale Krebsforschung (dktk), Partner Site Munich, Munich, Germany
| | - Stephanie E Combs
- Department of Radiation Oncology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany.,Department of Radiation Sciences (DRS), Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany.,Deutsches Konsortium für Translationale Krebsforschung (dktk), Partner Site Munich, Munich, Germany
| | - Ernst J Rummeny
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
| | - Daniela Pfeiffer
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
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Greffier J, Frandon J, Hamard A, Teissier J, Pasquier H, Beregi J, Dabli D. Impact of iterative reconstructions on image quality and detectability of focal liver lesions in low-energy monochromatic images. Phys Med 2020; 77:36-42. [DOI: 10.1016/j.ejmp.2020.07.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/17/2020] [Accepted: 07/17/2020] [Indexed: 12/12/2022] Open
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Kim TM, Lee JM, Yoon JH, Joo I, Park SJ, Jeon SK, Schmidt B, Martin S. Prediction of microvascular invasion of hepatocellular carcinoma: value of volumetric iodine quantification using preoperative dual-energy computed tomography. Cancer Imaging 2020; 20:60. [PMID: 32811570 PMCID: PMC7433153 DOI: 10.1186/s40644-020-00338-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/07/2020] [Indexed: 01/10/2023] Open
Abstract
Background To investigate the potential value of volumetric iodine quantification using preoperative dual-energy computed tomography (DECT) for predicting microvascular invasion (MVI) of hepatocellular carcinoma (HCC). Methods This retrospective study included patients with single HCC treated through surgical resection who underwent preoperative DECT. Quantitative DECT features, including normalized iodine concentration (NIC) to the aorta and mixed-energy CT attenuation value in the arterial phase, were three-dimensionally measured for peritumoral and intratumoral regions: (i) layer-by-layer analysis for peritumoral layers (outer layers 1 and 2; numbered in close order from the tumor boundary) and intratumoral layers (inner layers 1 and 2) with 2-mm layer thickness and (ii) volume of interest (VOI)-based analysis with different volume coverage (tumor itself; VOIO1, tumor plus outer layer 1; VOIO2, tumor plus outer layers 1 and 2; VOII1, tumor minus inner layer 1; VOII2, tumor minus inner layers 1 and 2). In addition, qualitative CT features, including peritumoral enhancement and tumor margin, were assessed. Qualitative and quantitative CT features were compared between HCC patients with and without MVI. Diagnostic performance of DECT parameters of layers and VOIs was assessed using receiver operating characteristic curve analysis. Results A total of 36 patients (24 men, mean age 59.9 ± 8.5 years) with MVI (n = 14) and without MVI (n = 22) were included. HCCs with MVI showed significantly higher NICs of outer layer 1, outer layer 2, VOIO1, and VOIO2 than those without MVI (P = 0.01, 0.04, 0.02, 0.02, respectively). Among the NICs of layers and VOIs, the highest area under the curve was obtained in outer layer 1 (0.747). Qualitative features, including peritumoral enhancement and tumor margin, and the mean CT attenuation of each layer and each VOI were not significantly different between HCCs with and without MVI (both P > 0.05). Conclusions Volumetric iodine quantification of peritumoral and intratumoral regions in arterial phase using DECT may help predict the MVI of HCC.
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Affiliation(s)
- Taek Min Kim
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea.,Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea. .,Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea. .,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea.
| | - Jeong Hee Yoon
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea.,Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
| | - Ijin Joo
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea.,Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
| | - Sae-Jin Park
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea.,Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
| | - Sun Kyung Jeon
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea.,Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
| | - Bernhard Schmidt
- Research and development department, Siemens Healthineers, Forchheim, Germany
| | - Sedlmair Martin
- Research and development department, Siemens Healthineers, Forchheim, Germany
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Çamlıdağ İ, Nural MS, Kalkan C, Danacı M. Discrimination of papillary renal cell carcinoma from benign proteinaceous cyst based on iodine and water content on rapid kV-switching dual-energy CT. ACTA ACUST UNITED AC 2020; 26:390-395. [PMID: 32755880 DOI: 10.5152/dir.2020.19483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE We aimed to evaluate whether rapid kV-switching dual energy CT (rsDECT) can discriminate between papillary renal cell carcinoma (RCC) and benign proteinaceous cysts (BPCs) based on iodine and water content. METHODS Twenty-four patients with histopathologically proven papillary RCC and 38 patients with 41 BPCs were retrospectively included. Patients with BPCs were eligible for inclusion when the cysts were stable in size and appearance for at least 2 years or proved to be a cyst on ultrasound or MRI. All patients underwent delayed phase (70-90 s) rsDECT. Iodine and water content of each lesion was measured on the workstation. RESULTS Of papillary RCC patients, 4 (16%) were female and 20 (84%) were male. Mean tumor size was 39±20 mm. Mean iodine and water content was 2.08±0.7 mg/mL and 1021±14 mg/mL, respectively. Of BPC patients, 9 were female and 29 were male. Mean cyst size was 20±7 mm. Mean iodine and water content was 0.82±0.4 mg/mL and 1012±14 mg/mL, respectively. There were significant differences between iodine and water contents of papillary RCCs and BPCs (P < 0.001). The best cutoff of iodine content for differentiating papillary RCC from BPC was 1.21 mg/mL (area under the curve [AUC]=0.97, P < 0.001, sensitivity 96%, specificity 88%, positive predictive value [PPV] 82%, negative predictive value [NPV] 97%, accuracy 91%,); the best cutoff of water content was 1015.5 mg/mL (AUC=0.68, P = 0.016, sensitivity 83%, specificity 56%, PPV 52%, NPV 85%, accuracy 66%). CONCLUSION An iodine content threshold of 1.21 mg/mL accurately differentiates papillary RCC from BPCs on a single postcontrast rsDECT. Despite having a high sensitivity, water content has inferior diagnostic accuracy.
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Affiliation(s)
- İlkay Çamlıdağ
- Department of Radiology, Ondokuz Mayıs University School of Medicine, Samsun, Turkey
| | - Mehmet Selim Nural
- Department of Radiology, Ondokuz Mayıs University School of Medicine, Samsun, Turkey
| | - Cihan Kalkan
- Department of Radiology, Ondokuz Mayıs University School of Medicine, Samsun, Turkey
| | - Murat Danacı
- Department of Urology, Ondokuz Mayıs University School of Medicine, Samsun, Turkey
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Xie H, Ren Y, Long W, Yang X, Tang X. Principal Component Analysis in Projection and Image Domains-Another Form of Spectral Imaging in Photon-Counting CT. IEEE Trans Biomed Eng 2020; 68:1074-1083. [PMID: 32746078 DOI: 10.1109/tbme.2020.3013491] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE We explore the feasibility of principal component analysis (PCA) as a form of spectral imaging in photon-counting CT. METHODS Using the data acquired by a prototype system and simulated by computer, we investigate the feasibility of spectral imaging in photon-counting CT via PCA for feature extraction and study the impacts made by data standardization and de-noising on its performance. RESULTS The PCA in the projection domain maintains the data consistence that is essential for tomographic image reconstruction and performs virtually the same as that in the image domain. The first three primary components account for more than 99.99% covariance of the data. Within anticipation, the contrast-to-noise ratio (CNR) between the target and background in the first principal component image can be larger than that in the image generated from the data acquired in each energy bin. More importantly, the CNR in the first principal component image may be larger than that in the image formed by the summed data acquired in all energy bins (i.e., the conventional polychromatic CT image). In addition, de-noising can not only reduce the noise in images but also improve the effectiveness/efficiency of PCA in feature extraction. CONCLUSION The PCA in either projection or image domain provides another form of spectral imaging in photon-counting CT that fits the essential requirements on spectral imaging in true color. SIGNIFICANCE The verification of PCA's feasibility in CT as a form spectral imaging and observation of its potential superiority in CNR over conventional polychromatic CT are meaningful in theory and practice.
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Zhou Y, Su GY, Hu H, Ge YQ, Si Y, Shen MP, Xu XQ, Wu FY. Radiomics analysis of dual-energy CT-derived iodine maps for diagnosing metastatic cervical lymph nodes in patients with papillary thyroid cancer. Eur Radiol 2020; 30:6251-6262. [PMID: 32500193 DOI: 10.1007/s00330-020-06866-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/14/2020] [Accepted: 04/06/2020] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To investigate the value of radiomics analysis of dual-energy computed tomography (DECT)-derived iodine maps for preoperative diagnosing cervical lymph nodes (LNs) metastasis in patients with papillary thyroid cancer (PTC). METHODS Two hundred and fifty-five LNs (143 non-metastatic and 112 metastatic) were enrolled and allocated to training and validation sets (7:3 ratio). Radiomics features were extracted from arterial and venous phase iodine maps, respectively. Radiomics signature was constructed based on reproducible features using the least absolute shrinkage and selection operator (LASSO) logistic regression algorithm with 10-fold cross-validation. Logistic regression modeling was employed to build models based on CT image features (model 1), radiomics signature (model 2), and the combined (model 3). A nomogram was plotted for the combined model and decision curve analysis was applied for clinical use. Diagnostic performance was assessed and compared. Internal validation was performed on an independent set containing 78 LNs. RESULTS Model 3 showed optimal diagnostic performance in both training (AUC = 0.933) and validation set (AUC = 0.895), followed by model 2 (training set, AUC = 0.910; validation set, AUC = 0.847). Both these two models outperformed model 1 in both training (AUC = 0.763) (p < 0.05) and validation set (AUC = 0.728) (p < 0.05). CONCLUSION Radiomics analysis of DECT-derived iodine maps showed better diagnostic performance than qualitative evaluation of CT image features in preoperative diagnosing cervical LN metastasis in PTC patients. Radiomics signature integrated with CT image features can serve as a promising imaging biomarker for the differentiation. KEY POINTS • Conventional CT image features have limited value for the diagnosis of metastatic LNs in PTC patients. • Radiomics analysis of dual-energy CT-derived iodine maps significantly outperformed qualitative CT image features in differentiating metastatic from non-metastatic LNs. • Radiomics signature integrated with qualitative CT image features can serve as a useful tool in judging LNs status, thus aiding clinical decision-making.
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Affiliation(s)
- Yan Zhou
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd, Gulou District, Nanjing, 210029, People's Republic of China
| | - Guo-Yi Su
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd, Gulou District, Nanjing, 210029, People's Republic of China
| | - Hao Hu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd, Gulou District, Nanjing, 210029, People's Republic of China
| | - Ying-Qian Ge
- Siemens Healthineers, Shanghai, People's Republic of China
| | - Yan Si
- Department of Thyroid Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Mei-Ping Shen
- Department of Thyroid Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Xiao-Quan Xu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd, Gulou District, Nanjing, 210029, People's Republic of China.
| | - Fei-Yun Wu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300, Guangzhou Rd, Gulou District, Nanjing, 210029, People's Republic of China.
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DiMaso LD, Miller JR, Lawless MJ, Bassetti MF, DeWerd LA, Huang J. Investigating split-filter dual-energy CT for improving liver tumor visibility for radiation therapy. J Appl Clin Med Phys 2020; 21:249-255. [PMID: 32410336 PMCID: PMC7484851 DOI: 10.1002/acm2.12904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/20/2020] [Accepted: 04/16/2020] [Indexed: 11/17/2022] Open
Abstract
Purpose Accurate liver tumor delineation is crucial for radiation therapy, but liver tumor volumes are difficult to visualize with conventional single‐energy CT. This work investigates the use of split‐filter dual‐energy CT (DECT) for liver tumor visibility by quantifying contrast and contrast‐to‐noise ratio (CNR). Methods Split‐filter DECT contrast‐enhanced scans of 20 liver tumors including cholangiocarcinomas, hepatocellular carcinomas, and liver metastases were acquired. Analysis was performed on the arterial and venous phases of mixed 120 kVp‐equivalent images and VMIs at 57 keV and 40 keV gross target volume (GTV) contrast and CNR were calculated. Results For the arterial phase, liver GTV contrast was 12.1 ± 10.0 HU and 43.1 ± 32.3 HU (P < 0.001) for the mixed images and 40 keV VMIs. Image noise increased on average by 116% for the 40 keV VMIs compared to the mixed images. The average CNR did not change significantly (1.6 ± 1.5, 1.7 ± 1.4, 2.4 ± 1.7 for the mixed, 57 keV and 40 keV VMIs (P > 0.141)). For individual cases, however, CNR increases of up to 607% were measured for the 40 keV VMIs compared to the mixed image. Venous phase 40 keV VMIs demonstrated an average increase of 35.4 HU in GTV contrast and 121% increase in image noise. Average CNR values were also not statistically different, but for individual cases CNR increases of up to 554% were measured for the 40 keV VMIs compared to the mixed image. Conclusions Liver tumor contrast was significantly improved using split‐filter DECT 40 keV VMIs compared to mixed images. On average, there was no statistical difference in CNR between the mixed images and VMIs, but for individual cases, CNR was greatly increased for the 57 keV and 40 keV VMIs. Therefore, although not universally successful for our patient cohort, split‐filter DECT VMIs may provide substantial gains in tumor visibility of certain liver cases for radiation therapy treatment planning.
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Affiliation(s)
- Lianna D. DiMaso
- Department of Medical PhysicsUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Jessica R. Miller
- Department of Human OncologyUniversity of Wisconsin‐MadisonMadisonWIUSA
| | | | | | - Larry A. DeWerd
- Department of Medical PhysicsUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Jessie Huang
- Department of Human OncologyUniversity of Wisconsin‐MadisonMadisonWIUSA
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Sauter AP, Shapira N, Kopp FK, Aichele J, Bodden J, Knipfer A, Rummeny EJ, Noël PB. CTPA with a conventional CT at 100 kVp vs. a spectral-detector CT at 120 kVp: Comparison of radiation exposure, diagnostic performance and image quality. Eur J Radiol Open 2020; 7:100234. [PMID: 32420413 PMCID: PMC7215101 DOI: 10.1016/j.ejro.2020.100234] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/10/2020] [Accepted: 04/18/2020] [Indexed: 12/15/2022] Open
Abstract
With SD-CT, increased radiation exposure is not present. In the current study, CTDIvol was lower with SD-CT than with C-CT, even when 100 kVp was used for the latter. With SD-CT, higher levels of diagnostic performance and image quality can be achieved. SD-CT may be the system of choice due to the availability of spectral data and thus additional image information.
Purpose To compare CT pulmonary angiographies (CTPAs) as well as phantom scans obtained at 100 kVp with a conventional CT (C-CT) to virtual monochromatic images (VMI) obtained with a spectral detector CT (SD-CT) at equivalent dose levels as well as to compare the radiation exposure of both systems. Material and Methods In total, 2110 patients with suspected pulmonary embolism (PE) were examined with both systems. For each system (C-CT and SD-CT), imaging data of 30 patients with the same mean CT dose index (4.85 mGy) was used for the reader study. C-CT was performed with 100 kVp and SD-CT was performed with 120 kVp; for SD-CT, virtual monochromatic images (VMI) with 40, 60 and 70 keV were calculated. All datasets were evaluated by three blinded radiologists regarding image quality, diagnostic confidence and diagnostic performance (sensitivity, specificity). Contrast-to-noise ratio (CNR) for different iodine concentrations was evaluated in a phantom study. Results CNR was significantly higher with VMI at 40 keV compared to all other datasets. Subjective image quality as well as sensitivity and specificity showed the highest values with VMI at 60 keV and 70 keV. Hereby, a significant difference to 100 kVp (C-CT) was found for image quality. The highest sensitivity was found using VMI at 60 keV with a sensitivity of more than 97 % for all localizations of PE. For diagnostic confidence and subjective contrast, highest values were found with VMI at 40 keV. Conclusion Higher levels of diagnostic performance and image quality were achieved for CPTAs with SD-CT compared to C-CT given similar dose levels. In the clinical setting SD-CT may be the modality of choice as additional spectral information can be obtained.
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Key Words
- BMI, body mass index
- C-CT, conventional spiral CT
- CNR, contrast-to-noise ratio
- CT, computed tomography
- CTDIVOL, volume-weighted CT dose index
- CTPA, CT pulmonary angiography
- Computed tomography angiography
- DE-CT, dual-Energy CT
- DLP, dose length product
- DS-CT, dual-Source CT
- ED, effective dose
- HU, Hounsfield Units
- IQ, image quality
- PE, pulmonary embolism
- Patient safety
- Pulmonary embolism
- ROI, region of interest
- Radiation exposure
- Radiologic
- SD-CT, spectral-detector CT
- Technology
- VMI, virtual monochromatic images
- kVp, peak kilovoltage
- keV, kilo-electronvolt
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Affiliation(s)
- Andreas P Sauter
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Nadav Shapira
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.,Philips Healthcare, Haifa, Israel
| | - Felix K Kopp
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Juliane Aichele
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Jannis Bodden
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Andreas Knipfer
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Ernst J Rummeny
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany
| | - Peter B Noël
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology, Munich, Germany.,Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
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Dual-Energy CT of Pediatric Abdominal Oncology Imaging: Private Tour of New Applications of CT Technology. AJR Am J Roentgenol 2020; 214:967-975. [DOI: 10.2214/ajr.19.22242] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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83
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Abstract
MRI and MRCP play an important role in the diagnosis of chronic pancreatitis (CP) by imaging pancreatic parenchyma and ducts. MRI/MRCP is more widely used than computed tomography (CT) for mild to moderate CP due to its increased sensitivity for pancreatic ductal and gland changes; however, it does not detect the calcifications seen in advanced CP. Quantitative MR imaging offers potential advantages over conventional qualitative imaging, including simplicity of analysis, quantitative and population-based comparisons, and more direct interpretation of detected changes. These techniques may provide quantitative metrics for determining the presence and severity of acinar cell loss and aid in the diagnosis of chronic pancreatitis. Given the fact that the parenchymal changes of CP precede the ductal involvement, there would be a significant benefit from developing MRI/MRCP-based, more robust diagnostic criteria combining ductal and parenchymal findings. Among cross-sectional imaging modalities, multi-detector CT (MDCT) has been a cornerstone for evaluating chronic pancreatitis (CP) since it is ubiquitous, assesses primary disease process, identifies complications like pseudocyst or vascular thrombosis with high sensitivity and specificity, guides therapeutic management decisions, and provides images with isotropic resolution within seconds. Conventional MDCT has certain limitations and is reserved to provide predominantly morphological (e.g., calcifications, organ size) rather than functional information. The emerging applications of radiomics and artificial intelligence are poised to extend the current capabilities of MDCT. In this review article, we will review advanced imaging techniques by MRI, MRCP, CT, and ultrasound.
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Elsherif SB, Zheng S, Ganeshan D, Iyer R, Wei W, Bhosale PR. Does dual-energy CT differentiate benign and malignant ovarian tumours? Clin Radiol 2020; 75:606-614. [PMID: 32252992 DOI: 10.1016/j.crad.2020.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 03/09/2020] [Indexed: 01/19/2023]
Abstract
AIM To assess the ability of dual-energy computed tomography (DECT) to distinguish benign from malignant ovarian tumours (OTs). MATERIALS AND METHODS Following approval of the institutional review board, the institutional database was mined for treatment-naive patients who underwent primary cytoreduction for OT. Thirty-seven patients were included and divided into those with benign OTs (n = 11) and malignant OTs (n = 26), including high-grade (n = 20) and low-grade (n = 6) malignant OTs. Advanced processing and region of interest delineation on the ovarian mass were performed using the preoperative staging DECT examination using the Advantage Workstation. The pixel-level data of the CT attenuation values at 50, 70, and 120 keV and the effective atomic number (Zeff), water content (WC), and iodine content (IC) in the ovarian mass were recorded. The Wilcoxon rank-sum test was used to compare CT attenuation data at different voltages, Zeff, and WC and IC levels between benign and malignant OTs and between high- and low-grade malignant OTs. Simple logistic regression was used to correlate the imaging characteristics with malignant status and grade. RESULTS Malignant OTs had significantly higher Zeff and IC compared with benign OTs. The threshold values for the diagnosis of malignant OT were IC≥9.74 (100 μg/cm3) with 81% sensitivity and 73% specificity and Zeff ≥8.16 with 85% sensitivity and 73% specificity. High-grade OTs had significantly higher WC compared with low-grade OTs, and a threshold of ≥1,013.92 mg/cm3 differentiated them with 80% sensitivity and 83% specificity. CONCLUSION DECT may be a tool to help distinguish malignant and benign OTs and predict tumour grade.
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Affiliation(s)
- S B Elsherif
- Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1400 Pressler St., Houston, TX 77030, USA.
| | - S Zheng
- Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center at Houston McGovern Medical School, MSB 2.130B, 6431 Fannin Street, Houston, TX 77030 Houston, Texas, USA
| | - D Ganeshan
- Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1400 Pressler St., Houston, TX 77030, USA
| | - R Iyer
- Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1400 Pressler St., Houston, TX 77030, USA
| | - W Wei
- Taussig Cancer Institute, Cleveland Clinic, 9500 Euclid Ave., Cleveland, OH 44195, USA; Department of Biostatistics, The University of Texas MD Anderson Cancer Center, 1400 Pressler St., Houston, TX 77030, USA
| | - P R Bhosale
- Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1400 Pressler St., Houston, TX 77030, USA
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Shapira N, Fokuhl J, Schultheiß M, Beck S, Kopp FK, Pfeiffer D, Dangelmaier J, Pahn G, Sauter AP, Renger B, Fingerle AA, Rummeny EJ, Albarqouni S, Navab N, Noël PB. Liver lesion localisation and classification with convolutional neural networks: a comparison between conventional and spectral computed tomography. Biomed Phys Eng Express 2020; 6:015038. [DOI: 10.1088/2057-1976/ab6e18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Abstract
OBJECTIVE. The objective of this study was to demonstrate the feasibility of dual-energy CT (DECT) for locoregional staging of breast cancer and differentiation of tumor histotypes. MATERIALS AND METHODS. From January 2016 to July 2017, a total of 31 patients (mean [± SD] age, 55.8 ± 14.8 years) with breast cancer diagnosed by needle biopsy who underwent preoperative contrast-enhanced DECT for staging purposes were selected from a retrospective review of institutional databases. Monochromatic images obtained at 40 and 70 keV were evaluated by two readers who determining the number of hypervascularized tumors present and the largest tumor diameter for each breast. The attenuation values and iodine concentration of tumors and normal breast tissue and the ratios of these findings in each tissue type were recorded. Cancers were classified as ductal carcinoma in situ, invasive ductal carcinoma, and invasive lobular carcinoma. The reference standard was the final pathologic finding after surgery. RESULTS. A total of 64 tumor lesions were found at histopathologic analysis versus 67 on DECT for 34 breasts (three bilateral cancers were included). Nonparametric statistics were used. The largest lesion diameter observed DECT was 33.2 ± 20.5 mm versus 31.8 ± 20.5 mm on pathologic analysis, and cancer distribution was correctly classified for 31 of 34 (91%) cases. ROC curves derived from lesion iodine concentration showed that the optimal thresholds for distinguishing infiltrating carcinomas (invasive lobular and ductal carcinomas) and from other lesions were 1.70 mg/mL (sensitivity, 94.9%; specificity, 93.0%; AUC value, 0.968). ROC curves derived from the ratio of the iodine concentration in lesions to that in normal breast parenchyma showed that 6.13 was the optimal threshold to distinguish invasive ductal carcinoma from other lesions (sensitivity, 87.0%; specificity, 81.1%; AUC value, 0.914). CONCLUSION. DECT is feasible and seems to be a reliable tool for locoregional staging of breast cancer.
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Abstract
Since their discovery by Wilhelm Conrad Röntgen in 1895, X-rays have become the most widely available, typically fastest, and usually most cost-effective medical imaging modality today. From the early radiographic approaches using X-ray films as detectors, the portfolio of medical X-ray imaging devices developed into a large range of dedicated instrumentation for various applications. While X-ray imaging has come a long way, there are some physical properties of X-rays, which have not yet been fully exploited, and which may offer quite some room for further enhancements of current X-ray imaging equipment. Firstly, X-ray imaging today is mainly black and white, despite the fact that X-ray generators actually create a full spectrum of X-ray energies, and that the interactions of X-rays that occur within the human body are not the same for all energies and every material. Exploiting these spectral dependencies allows to not only obtain a black and white CT image, but also to obtain more molecularly specific information, which is relevant particularly in oncological precision radiology. The second aspect of X-rays, and so far in radiology mainly neglected and unused, is the physical fact that X-rays can also be interpreted in the wave picture, and not only as presently been done in the particle picture. If interpreted as waves, X-rays-just like visible light-experience a phase shift in matter, and this-if exploited correctly-can produce a new class of X-ray images, which then depict the wave interactions of X-rays with matter, rather than only the attenuating properties, as done until now.
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Trabzonlu TA, Mozaffary A, Kim D, Yaghmai V. Dual-energy CT evaluation of gastrointestinal bleeding. Abdom Radiol (NY) 2020; 45:1-14. [PMID: 31728614 DOI: 10.1007/s00261-019-02226-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Gastrointestinal bleeding is a common cause for hospital admissions and is an important cause of morbidity and mortality. Although endoscopy is accepted as the standard initial diagnostic modality for the evaluation of gastrointestinal bleeding, multiphasic computed tomography (CT) imaging has become an alternative diagnostic tool. Dual-energy CT with post-processing techniques may have additional advantages over single-energy computed tomography in evaluation of gastrointestinal bleeding. In this article, we discuss the role of dual-energy CT in the evaluation of gastrointestinal bleeding with potential advantages over conventional CT and limitations.
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89
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Skornitzke S, Kauczor HU, Stiller W. Measuring Dynamic CT Perfusion Based on Time-Resolved Quantitative DECT Iodine Maps: Comparison to Conventional Perfusion at 80 kVp for Pancreatic Carcinoma. Invest Radiol 2019; 54:689-696. [PMID: 31335633 DOI: 10.1097/rli.0000000000000591] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Using dual-energy computed tomography (DECT) for quantifying iodine content after injection of contrast agent could provide a quantitative basis for dynamic computed tomography (CT) perfusion measurements by means of established mathematical models of contrast agent kinetics, thus improving results by combining the strength of both techniques, which was investigated in this study. MATERIALS AND METHODS A dynamic DECT acquisition over 51 seconds performed at 80/Sn140 kVp in 17 patients with pancreatic carcinoma was used to calculate iodine-enhancement images for each time point by means of 3-material decomposition. After motion correction, perfusion maps of blood flow were calculated using the maximum-slope model from both 80 kVp image data and iodine-enhancement images. Blood flow was measured in regions of interest placed in healthy pancreatic tissue and carcinoma for both of the derived perfusion maps. To assess image quality of input data, an adjusted contrast-to-noise ratio was calculated for 80 kVp images and iodine-enhancement images. Susceptibility of perfusion results to residual patient breathing motion during acquisition was investigated by measuring blood flow in fatty tissue surrounding the pancreas, where blood flow should be negligible compared with the pancreas. RESULTS For both 80 kVp and iodine-enhancement images, blood flow was significantly higher in healthy tissue (114.2 ± 37.4 mL/100 mL/min or 115.1 ± 36.2 mL/100 mL/min, respectively) than in carcinoma (46.5 ± 26.6 mL/100 mL/min or 49.7 ± 24.7 mL/100 mL/min, respectively). Differences in blood flow between 80 kVp image data and iodine-enhancement images were statistically significant in healthy tissue, but not in carcinoma. For 80 kVp images, adjusted contrast-to-noise ratio was significantly higher (1.3 ± 1.1) than for iodine-enhancement images (1.1 ± 0.9). When evaluating fatty tissue surrounding the pancreas for estimating influence of patient motion, measured blood flow was significantly lower for iodine-enhancement images (30.7 ± 12.0 mL/100 mL/min) than for 80 kVp images (39.0 ± 19.1 mL/100 mL/min). Average patient radiation exposure was 8.01 mSv for dynamic DECT acquisition, compared with 4.60 mSv for dynamic 80 kVp acquisition. DISCUSSION Iodine enhancement images can be used to calculate CT perfusion maps of blood flow, and compared with 80 kVp images, results showed only a small difference of 1 mL/100 mL/min in blood flow in healthy tissue, whereas patient radiation exposure was increased for dynamic DECT. Perfusion maps calculated based on iodine-enhancement images showed lower blood flow in fatty tissues surrounding the pancreas, indicating reduced susceptibility to residual patient breathing motion during the acquisition.
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Affiliation(s)
- Stephan Skornitzke
- From the Diagnostic and Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany
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90
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Stieb S, Kiser K, van Dijk L, Livingstone NR, Elhalawani H, Elgohari B, McDonald B, Ventura J, Mohamed ASR, Fuller CD. Imaging for Response Assessment in Radiation Oncology: Current and Emerging Techniques. Hematol Oncol Clin North Am 2019; 34:293-306. [PMID: 31739950 DOI: 10.1016/j.hoc.2019.09.010] [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] [Indexed: 12/29/2022]
Abstract
Imaging in radiation oncology is essential for the evaluation of treatment response in tumors and organs at risk. This influences further treatment decisions and could possibly be used to adapt therapy. This review article focuses on the currently used imaging modalities for response assessment in radiation oncology and gives an overview of new and promising techniques within this field.
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Affiliation(s)
- Sonja Stieb
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Kendall Kiser
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Lisanne van Dijk
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Nadia Roxanne Livingstone
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Hesham Elhalawani
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Baher Elgohari
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Brigid McDonald
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Juan Ventura
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Abdallah Sherif Radwan Mohamed
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Clifton David Fuller
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
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91
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Lyu Q, O'Connor D, Niu T, Sheng K. Image-domain multimaterial decomposition for dual-energy computed tomography with nonconvex sparsity regularization. J Med Imaging (Bellingham) 2019; 6:044004. [PMID: 31620550 DOI: 10.1117/1.jmi.6.4.044004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 09/23/2019] [Indexed: 11/14/2022] Open
Abstract
Dual-energy computed tomography (CT) has the potential to decompose tissues into different materials. However, the classic direct inversion (DI) method for multimaterial decomposition (MMD) cannot accurately separate more than two basis materials due to the ill-posed problem and amplified image noise. We propose an integrated MMD method that addresses the piecewise smoothness and intrinsic sparsity property of the decomposition image. The proposed MMD was formulated as an optimization problem including a quadratic data fidelity term, an isotropic total variation term that encourages image smoothness, and a nonconvex penalty function that promotes decomposition image sparseness. The mass and volume conservation rule was formulated as the probability simplex constraint. An accelerated primal-dual splitting approach with line search was applied to solve the optimization problem. The proposed method with different penalty functions was compared against DI on a digital phantom, a Catphan® 600 phantom, a quantitative imaging phantom, and a pelvis patient. The proposed framework distinctly separated the CT image up to 12 basis materials plus air with high decomposition accuracy. The cross talks between two different materials are substantially reduced, as shown by the decreased nondiagonal elements of the normalized cross correlation (NCC) matrix. The mean square error of the measured electron densities was reduced by 72.6%. Across all datasets, the proposed method improved the average volume fraction accuracy from 61.2% to 99.9% and increased the diagonality of the NCC matrix from 0.73 to 0.96. Compared with DI, the proposed MMD framework improved decomposition accuracy and material separation.
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Affiliation(s)
- Qihui Lyu
- University of California Los Angeles, Department of Radiation Oncology, Los Angeles, California, United States
| | - Daniel O'Connor
- University of California Los Angeles, Department of Radiation Oncology, Los Angeles, California, United States
| | - Tianye Niu
- Zhejiang University School of Medicine, Sir Run Run Shaw Hospital, Hangzhou, China.,Zhejiang University, Institute of Translational Medicine, Hangzhou, China
| | - Ke Sheng
- University of California Los Angeles, Department of Radiation Oncology, Los Angeles, California, United States
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92
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Lim P, Barber J, Sykes J. Evaluation of dual energy CT and iterative metal artefact reduction (iMAR) for artefact reduction in radiation therapy. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:1025-1032. [PMID: 31602593 DOI: 10.1007/s13246-019-00801-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/19/2019] [Accepted: 09/16/2019] [Indexed: 11/27/2022]
Abstract
Metal artefacts pose a common problem in single energy computed tomography (SECT) images used for radiotherapy. Virtual monoenergetic (VME) images constructed with dual energy computed tomography (DECT) scans can be used to reduce beam hardening artefacts. Dual energy metal artefact reduction is compared and combined with iterative metal artefact reduction (iMAR) to determine optimal imaging strategies for patients with metal prostheses. SECT and DECT scans were performed on a Siemens Somatom AS-64 Slice CT scanner. Images were acquired of a modified CIRS pelvis phantom with 6, 12, 20 mm diameter stainless steel rods and VME images reconstructed at 100, 120, 140 and 190 keV. These were post-reconstructed with and without the iMAR algorithm. Artefact reduction was measured using: (1) the change in Hounsfield Unit (HU) with and without metal artefact reduction (MAR) for 4 regions of interest; (2) the total number of artefact pixels, defined as pixels with a difference (between images with metal rod and without) exceeding a threshold; (3) the difference in the mean pixel intensity of the artefact pixels. DECT, SECT + iMAR and DECT + iMAR were compared. Both SECT + iMAR and DECT + iMAR offer successful MAR for phantom simulating unilateral hip prosthesis. DECT gives minimal artefact reduction over iMAR alone. Quantitative metrics are advantageous for MAR analysis but have limitations that leave room for metric development.
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Affiliation(s)
- P Lim
- School of Physics, University of Sydney, Sydney, Australia.
| | - J Barber
- School of Physics, University of Sydney, Sydney, Australia
- Radiation Oncology, Blacktown Hospital, Sydney West Cancer Network, Sydney, Australia
| | - J Sykes
- School of Physics, University of Sydney, Sydney, Australia
- Radiation Oncology, Blacktown Hospital, Sydney West Cancer Network, Sydney, Australia
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93
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Taylor RE, Mager P, Yu NC, Katz DP, Brady JR, Gupta N. Iodine quantification and detectability thresholds among major dual-energy CT platforms. Br J Radiol 2019; 92:20190530. [PMID: 31559858 DOI: 10.1259/bjr.20190530] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVES To estimate the minimum detectable iodine concentration on multiple dual-energy CT (DECT) platforms. METHODS AND MATERIALS A phantom containing iodine concentrations ranging from 0 to 10 mg ml-1 was scanned with five dual-energy platforms (two rapid kilo volt switching (r-kVs), one dual source (DS), one sequential acquisition and one split-filter). Serial dilutions of 300 mg ml-1 iodinated contrast material were used to generate concentrations below 2 mg ml-1. Iodine density and virtual monoenergetic images were reviewed by three radiologists to determine the minimum visually detectable iodine concentration. Contrast-to-noise ratios (CNRs) were calculated. RESULTS 1 mg mL-1 (~0.8 mg mL-1 corrected) was the minimum visually detectable concentration among the platforms and could be seen by all readers on the third-generation r-kVs and DS platforms. CONCLUSIONS At low concentrations, CNR for monoenergetic images was highest on the DS platform and lowest in the sequential acquisition and split-filter platforms. ADVANCES IN KNOWLEDGE The results of this study corroborate previous in vivo estimates of iodine detection limits at DECT and provide a comparison for the performance of different DECT platforms at low iodine concentrations in vitro.
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Affiliation(s)
| | - Pamela Mager
- Department of Radiology, Houston Methodist Hospital, Houston, TX
| | - Nam C Yu
- Department of Radiology, Houston Methodist Hospital, Houston, TX
| | - David P Katz
- Department of Radiology, Houston Methodist Hospital, Houston, TX
| | - Jett R Brady
- Department of Radiology, Houston Methodist Hospital, Houston, TX
| | - Nakul Gupta
- Department of Radiology, Houston Methodist Hospital, Houston, TX
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94
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Corrias G, Sawan P, Mahmood U, Zheng J, Capanu M, Salvatore M, Spinato G, Saba L, Mannelli L. Dual energy computed tomography analysis in cancer patients: What factors affect iodine concentration in contrast enhanced studies? Eur J Radiol 2019; 120:108698. [PMID: 31600640 DOI: 10.1016/j.ejrad.2019.108698] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/28/2019] [Accepted: 09/26/2019] [Indexed: 12/15/2022]
Abstract
PURPOSE The aim of the study is to explore the patient's and scan's parameters that affect the iodine concentration in the abdomen using dual energy computed tomography (DECT) in an oncologic population. METHOD This is a retrospective study with consecutive patients with different cancers who underwent a single-source DECT (ssDECT) examinations at our institution between years 2015 and 2017. On axial IODINE images, the radiologist manually drew a circular ROI along the inner contour of the aorta. Mean iodine concentration and ROI areas were recorded. Body mass index for every patient was recorded. Descriptive statistics were summarized for iodine concentration and patient/scan characteristics. Linear regression was used to examine associations between iodine concentration in aorta and studied characteristics. Statistical significance was set at a p value < 0.05. RESULTS The univariate analysis, showed a statistically significant association between iodine concentration within the aorta and the area of ROI (Estimated Coefficient β: -0.013), the rate of injection (Estimated Coefficient β: 2.09), the acquisition time (Estimated Coefficient β: -0.195). In multivariable analysis iodine concentration in the aorta increased with higher rate of injection (4 ml/sec), smaller ROI area and lower BMI. CONCLUSION Our results showed how iodine concentration is highly dependent on some intrinsic and extrinsic parameters of the examination. These parameters should be taken into account since lower concentration of iodine decrease contrast-to-noise ratio, and in longitudinal follow up studies, they would affect iodine quantitive assessments in cancer patients with frequent chemotherapy-induced variations in BMI and cardiac function.
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Affiliation(s)
- Giuseppe Corrias
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA; Department of Radiology, University of Cagliari, Via Università, 40, 09124, Cagliari, CA, Italy
| | - Peter Sawan
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Usman Mahmood
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Junting Zheng
- Department of Statistics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Marinela Capanu
- Department of Statistics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | | | - Giacomo Spinato
- Department of Neurosciences, Section of Otolaryngology and Regional Centre for Head and Neck Cancer, University of Padova, Treviso, Italy; Department of Surgery, Oncology and Gastroenterology, Section of Oncology and Immunology, University of Padova, Padova, Italy
| | - Luca Saba
- Department of Radiology, University of Cagliari, Via Università, 40, 09124, Cagliari, CA, Italy
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95
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El Kayal N, Lennartz S, Ekdawi S, Holz J, Slebocki K, Haneder S, Wybranski C, Mohallel A, Eid M, Grüll H, Persigehl T, Borggrefe J, Maintz D, Heneweer C. Value of spectral detector computed tomography for assessment of pancreatic lesions. Eur J Radiol 2019; 118:215-222. [DOI: 10.1016/j.ejrad.2019.07.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/08/2019] [Accepted: 07/15/2019] [Indexed: 01/05/2023]
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96
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Kang HJ, Lee JM, Lee SM, Yang HK, Kim RH, Nam JG, Karnawat A, Han JK. Value of virtual monochromatic spectral image of dual-layer spectral detector CT with noise reduction algorithm for image quality improvement in obese simulated body phantom. BMC Med Imaging 2019; 19:76. [PMID: 31462212 PMCID: PMC6714289 DOI: 10.1186/s12880-019-0367-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 08/05/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Dual-layer spectral detector CT (SDCT) may provide several theoretical advantages over pre-existing DECT approaches in terms of adjustment-free sampling number and dose modulation, beam hardening correction, and production spectral images by post-processing. In addition, by adopting noise reduction algorithm, high contrast resolution was expected even in low keV level. We surmised that this improvement would be beneficial to obese people. Therefore, our aim of study is to compare image quality of virtual monochromatic spectral images (VMI) and polychromatic images reconstructed from SDCT with different body size and radiation dose using anthropomorphic liver phantom. METHODS One small and one large size of body phantoms, each containing eight (four high- and four low-contrast) simulated focal liver lesions (FLLs) were scanned by SDCT (at 120 kVp) using different Dose Right Indexes (DRIs). VMI were reconstructed from spectral base images from 40 keV to 200 keV. Hybrid iterative reconstruction (iDose4) was used for polychromatic image reconstruction. Image noise and contrast to noise ratio (CNR) were compared. Five radiologists independently rated lesion conspicuity, diagnostic acceptability and subjective noise level in every image sets, and determined optimal keV level in VMI. RESULTS Compare with conventional polychromatic images, VMI showed superior CNR at low keV level regardless of phantom size at every examined DRIs (Ps < 0.05). As body size increased, VMI had more gradual CNR decrease and noise increase than conventional polychromatic images. For low contrast FLLs in large phantom, lesion conspicuities at low radiation dose levels (DRI 16 and 19) were significantly increased in VMI (Ps < 0.05). Subjective image noise and diagnostic acceptabilities were significantly improved at VMI in both phantom size. CONCLUSIONS VMI of dual-layer spectral detector CT with noise reduction algorithm provides improved CNR, noise reduction, and better subjective image quality in imaging of obese simulated liver phantom compared with polychromatic images. This may hold promise for improving detection of liver lesions and improved imaging of obese patients.
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Affiliation(s)
- Hyo-Jin Kang
- Department of Radiology, Seoul National University Hospital, Seoul, 03080 South Korea
- Department of Radiology, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul, 03080 South Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul, 03080 South Korea
- Department of Radiology, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul, 03080 South Korea
- Institute of Radiation Medicine, Seoul National University College Medical Research Center, Seoul, 03080 South Korea
| | - Sang Min Lee
- Department of Radiology, Hallym University Sacred Heart Hospital, Anyang, 14068 South Korea
| | - Hyun Kyung Yang
- Department of Medical imaging, Toronto General hospital, Toronto, Canada
| | - Ri Hyeon Kim
- Department of Radiology, Seoul National University Hospital, Seoul, 03080 South Korea
| | - Ju Gang Nam
- Department of Radiology, Seoul National University Hospital, Seoul, 03080 South Korea
| | - Aruna Karnawat
- Department of Radiology, Nizam’s Institute of Medical Sciences, Hyderabad, 500082 India
| | - Joon Koo Han
- Department of Radiology, Seoul National University Hospital, Seoul, 03080 South Korea
- Department of Radiology, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul, 03080 South Korea
- Institute of Radiation Medicine, Seoul National University College Medical Research Center, Seoul, 03080 South Korea
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97
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Lennartz S, Große Hokamp N, Abdullayev N, Le Blanc M, Iuga AI, Bratke G, Zopfs D, Maintz D, Borggrefe J, Persigehl T. Diagnostic value of spectral reconstructions in detecting incidental skeletal muscle metastases in CT staging examinations. Cancer Imaging 2019; 19:50. [PMID: 31315666 PMCID: PMC6637569 DOI: 10.1186/s40644-019-0235-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/28/2019] [Indexed: 11/10/2022] Open
Abstract
Background To investigate if iodine density overlay maps (IDO) and virtual monoenergetic images at 40 keV (VMI40keV) acquired from spectral detector computed tomography (SDCT) can improve detection of incidental skeletal muscle metastases in whole-body CT staging examinations compared to conventional images. Methods In total, 40 consecutive cancer patients who underwent clinically-indicated, contrast-enhanced, oncologic staging SDCT were included at this retrospective study: 16 patients with n = 108 skeletal muscle metastases confirmed by prior or follow-up CT, 18F-FDG-PET, MRI or histopathology, and a control group of 24 patients without metastases. Four independent readers performed blinded, randomized visual detection of skeletal muscle metastases in conventional images, IDO and VMI40keV, indicating diagnostic certainty for each lesion on a 5-point Likert scale. Quantitatively, ROI-based measurements of attenuation (HU) in conventional images and VMI40keV and iodine concentration in IDO were conducted. CNR was calculated and receiver operating characteristics (ROC) analysis of quantitative parameters was performed. Results Regarding subjective assessment, IDO (63.2 (58.5–67.8) %) and VMI40keV (54.4 (49.6–59.2) %) showed an increased sensitivity for skeletal muscle metastases compared to conventional images (39.8 (35.2–44.6) %). Specificity was comparable in VMI40keV (69.8 (63.2–75.8) %) and conventional images (69.2 (60.6–76.9) %), while in IDO, it was moderately increased to 74.2 (65.3–78.4) %. Quantitative image analysis revealed that CNR of skeletal muscle metastases to circumjacent muscle was more than doubled in VMI40keV (25.8 ± 11.1) compared to conventional images (10.0 ± 5.3, p ≤ 0.001). Iodine concentration obtained from IDO and HU acquired from VMI40kev (AUC = 0.98 each) were superior to HU attenuation in conventional images (AUC = 0.94) regarding differentiation between healthy and metastatic muscular tissue (p ≤ 0.05). Conclusions IDO and VMI40keV provided by SDCT improve diagnostic accuracy in the assessment of incidental skeletal muscle metastases compared to conventional CT.
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Affiliation(s)
- Simon Lennartz
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Else Kröner Forschungskolleg Clonal Evolution in Cancer, University Hospital Cologne, Weyertal 115b, 50931, Cologne, Germany
| | - Nils Große Hokamp
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Department of Radiology, Case Western Reserve University and University Hospitals, Cleveland, OH, USA
| | - Nuran Abdullayev
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Markus Le Blanc
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Andra-Iza Iuga
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Grischa Bratke
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - David Zopfs
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - David Maintz
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Jan Borggrefe
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Thorsten Persigehl
- Department of Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
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98
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Topçuoğlu OM, Sarıkaya B. Fast kilovoltage-switching dual-energy CT offering lower x-ray dose than single-energy CT for the chest: a quantitative and qualitative comparison study of the two methods of acquisition. Diagn Interv Radiol 2019; 25:204-209. [PMID: 31085505 PMCID: PMC6521909 DOI: 10.5152/dir.2019.18412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/07/2018] [Accepted: 11/13/2018] [Indexed: 11/22/2022]
Abstract
PURPOSE We aimed to compare the size-specific dose estimates (SSDE), computed tomography (CT) dose indices and image quality parameters of the chest CTs obtained with fast kilovoltage-switching (FKS) dual-energy (DE) CT versus those with single-energy (SE) CT. METHODS Patients who had chest SECT within the last 6 months were prospectively scanned with chest FKS-DECT. Quantitative comparison was made by calculating the mean SSDE, CTDIvol, contrast, noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) for both acquisitions. Two radiologists evaluated the chest SECT and DECT images qualitatively blinded to the technique used. The paired Student's t test was utilized for comparing the quantitative and qualitative data. Inter- and intraobserver agreement were also assessed. RESULTS A total of 42 patients were included. The mean SSDE, CTDIvol, contrast, noise, CNR, and SNR for SECT versus DECT were 12.7±2.2 mGy vs. 9.3±1.2 mGy (P = 0.001), 10.9±2.4 mGy vs. 8±1.2 mGy (P < 0.001), 211.9±44.7 vs. 216.3±59 (P = 0.350), 12.9±2.4 vs. 13.9±3.7 (P = 0.086), 13.5±5.2 vs. 13.3±8.4 (P = 0.548) and 12±3.5 vs. 11.5±3.4 (P = 0.774), respectively. Interobserver reproducibility was high for contrast, noise, CNR, and SNR (ICC = 0.89, 0.85, 0.93, and 0.82, respectively; all P < 0.05). Intraobserver reproducibility was high for contrast, noise, CNR, and SNR (ICC = 0.80, 0.77, 0.85, and 0.88, respectively; all P < 0.05). CONCLUSION The mean SSDE of the chest CTs obtained with FKS-DECT were 26.8% lower than those with SECT with significant difference for the objective assessment and there was no significant difference for the subjective assessment of the image qualities, in this series.
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Affiliation(s)
- Osman Melih Topçuoğlu
- From the Department of Radiology (O.M.T. ) Yeditepe University School of Medicine, İstanbul, Turkey
| | - Başar Sarıkaya
- From the Department of Radiology (O.M.T. ) Yeditepe University School of Medicine, İstanbul, Turkey
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99
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Çamlıdağ İ, Nural MS, Danacı M, Özden E. Usefulness of rapid kV-switching dual energy CT in renal tumor characterization. Abdom Radiol (NY) 2019; 44:1841-1849. [PMID: 30637472 DOI: 10.1007/s00261-019-01897-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE To investigate whether iodine content can discriminate between benign or malignant renal tumors, malign tumor subtypes, low-grade and high-grade tumors on rapid kv-switching dual-energy CT (rsDECT). METHODS This prospective study enrolled 95 patients with renal tumors who underwent rsDECT for tumor characterization between 2016 and 2018. Attenuation on true and virtual unenhanced images, absolute enhancement and enhancement ratio and iodine content of each lesion on nephrographic phase iodine density images were measured. Histopathological diagnosis was obtained following either surgery or core biopsy. RESULTS Eighty-five tumors were renal cell carcinoma (RCC) (56 clear cell, 20 papillary, 9 chromophobe) and 10 were benign (6 angiomyolipoma,4 oncocytoma). 46 tumors were low-grade and 23 high-grade. There was significant difference between iodine content of clear cell and non-clear cell (papillary + chromophobe) RCC (p < 0.001). However, no significant iodine content differences were found between papillary and chromophobe RCC, benign and malignant tumors, low-grade and high-grade tumors. The best cut-off iodine content for differentiating clear cell from non-clear cell RCC was 3.2 mg/ml and clear cell from papillary RCC was 2.9 mg/ml with a high sensitivity and specificity. Also, significant difference was found between attenuation values of true and virtual unenhanced images (p = 0.007). Mean iodine content, absolute enhancement and enhancement ratio were highly correlated. CONCLUSION rsDECT contributes to renal tumor characterization by showing higher iodine content in clear cell RCCs compared with non-clear cell RCCs.
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Parakh A, Negreros-Osuna AA, Patino M, McNulty F, Kambadakone A, Sahani DV. Low-keV and Low-kVp CT for Positive Oral Contrast Media in Patients with Cancer: A Randomized Clinical Trial. Radiology 2019; 291:620-629. [PMID: 30964423 DOI: 10.1148/radiol.2019182393] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background Substantial gain in the attenuation of iodine on low-kVp and dual-energy CT processed low-keV virtual monochromatic images provides an opportunity for customization of positive oral contrast media administration. Purpose To perform an intrapatient comparison of bowel labeling, opacification, and taste preference with iodinated oral contrast medium (ICM) in standard (sICM) and 25%-reduced (rICM) concentrations at low tube voltage (100 kVp) or on low-energy (50-70 keV) virtual monochromatic images compared with barium-based oral contrast medium (BCM) at 120 kVp. Materials and Methods In this prospective clinical trial, 200 adults (97 men, 103 women; mean age, 63 years ± 13 [standard deviation]) who weighed less than 113 kg and who were undergoing oncologic surveillance (from April 2017 to July 2018) and who had previously undergone 120-kVp abdominopelvic CT with BCM randomly received sICM (7.2 g iodine) or rICM (5.4 g iodine) and underwent 100-kVp CT or dual-energy CT (80/140 kVp) scans to be in one of four groups (n = 50 each): sICM/100 kVp, rICM/100 kVp, sICM/dual-energy CT, and rICM/dual-energy CT. Qualitative analysis was performed for image quality (with a five-point scale), extent of bowel labeling, and homogeneity of opacification (with a four-point scale). Intraluminal attenuation of opacified small bowel was measured. A post-CT patient survey was performed to indicate contrast medium preference, taste of ICM (with a five-point scale), and adverse effects. Data were analyzed with analogs of analysis of variance. Results All CT studies were of diagnostic image quality (3.4 ± 0.3), with no difference in the degree of bowel opacification between sICM and rICM (P > .05). Compared with BCM/120 kVp (282 HU ± 73), mean attenuation was 78% higher with sICM/100 kVp (459 HU ± 282) and 26%-121% higher at sICM/50-65 keV (50 keV = 626 HU ± 285; 65 keV = 356 HU ± 171). With rICM, attenuation was 46% higher for 100 kVp (385 HU ± 215) and 19%-108% higher for 50-65 keV (50 keV = 567 HU ± 270; 65 keV = 325 HU ± 156) compared with BCM (P < .05). A total of 171 of 200 study participants preferred ICM to BCM, with no taste differences between sICM and rICM (3.9 ± 0.6). Fifteen participants had diarrhea with BCM, but none had diarrhea with ICM. Conclusion A 25%-reduced concentration of iodinated oral contrast medium resulted in acceptable bowel labeling while yielding substantially higher luminal attenuation at low-kVp and low-keV CT examinations with improved preference in patients undergoing treatment for cancer. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Laghi in this issue.
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Affiliation(s)
- Anushri Parakh
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Adrian Antonio Negreros-Osuna
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Manuel Patino
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Fredrick McNulty
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Avinash Kambadakone
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Dushyant V Sahani
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
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