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Callegari S, Feher A, Smolderen KG, Mena-Hurtado C, Sinusas AJ. Multi-modality imaging for assessment of the microcirculation in peripheral artery disease: Bench to clinical practice. AMERICAN HEART JOURNAL PLUS : CARDIOLOGY RESEARCH AND PRACTICE 2024; 42:100400. [PMID: 38779485 PMCID: PMC11108852 DOI: 10.1016/j.ahjo.2024.100400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024]
Abstract
Peripheral artery disease (PAD) is a highly prevalent disorder with a high risk of mortality and amputation despite the introduction of novel medical and procedural treatments. Microvascular disease (MVD) is common among patients with PAD, and despite the established role as a predictor of amputations and mortality, MVD is not routinely assessed as part of current standard practice. Recent pre-clinical and clinical perfusion and molecular imaging studies have confirmed the important role of MVD in the pathogenesis and outcomes of PAD. The recent advancements in the imaging of the peripheral microcirculation could lead to a better understanding of the pathophysiology of PAD, and result in improved risk stratification, and our evaluation of response to therapies. In this review, we will discuss the current understanding of the anatomy and physiology of peripheral microcirculation, and the role of imaging for assessment of perfusion in PAD, and the latest advancements in molecular imaging. By highlighting the latest advancements in multi-modality imaging of the peripheral microcirculation, we aim to underscore the most promising imaging approaches and highlight potential research opportunities, with the goal of translating these approaches for improved and personalized management of PAD in the future.
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Affiliation(s)
- Santiago Callegari
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Vascular Medicine Outcomes Program, Yale University, New Haven, CT, USA
| | - Attila Feher
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Kim G. Smolderen
- Vascular Medicine Outcomes Program, Yale University, New Haven, CT, USA
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Carlos Mena-Hurtado
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Vascular Medicine Outcomes Program, Yale University, New Haven, CT, USA
| | - Albert J. Sinusas
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, USA
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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2
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Abu-Omar A, Murray N, Ali IT, Khosa F, Barrett S, Sheikh A, Nicolaou S, Tamburrini S, Iacobellis F, Sica G, Granata V, Saba L, Masala S, Scaglione M. Utility of Dual-Energy Computed Tomography in Clinical Conundra. Diagnostics (Basel) 2024; 14:775. [PMID: 38611688 PMCID: PMC11012177 DOI: 10.3390/diagnostics14070775] [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: 01/29/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Advancing medical technology revolutionizes our ability to diagnose various disease processes. Conventional Single-Energy Computed Tomography (SECT) has multiple inherent limitations for providing definite diagnoses in certain clinical contexts. Dual-Energy Computed Tomography (DECT) has been in use since 2006 and has constantly evolved providing various applications to assist radiologists in reaching certain diagnoses SECT is rather unable to identify. DECT may also complement the role of SECT by supporting radiologists to confidently make diagnoses in certain clinically challenging scenarios. In this review article, we briefly describe the principles of X-ray attenuation. We detail principles for DECT and describe multiple systems associated with this technology. We describe various DECT techniques and algorithms including virtual monoenergetic imaging (VMI), virtual non-contrast (VNC) imaging, Iodine quantification techniques including Iodine overlay map (IOM), and two- and three-material decomposition algorithms that can be utilized to demonstrate a multitude of pathologies. Lastly, we provide our readers commentary on examples pertaining to the practical implementation of DECT's diverse techniques in the Gastrointestinal, Genitourinary, Biliary, Musculoskeletal, and Neuroradiology systems.
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Affiliation(s)
- Ahmad Abu-Omar
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Nicolas Murray
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Ismail T. Ali
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Faisal Khosa
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Sarah Barrett
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Adnan Sheikh
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Savvas Nicolaou
- Department of Emergency Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC V5Z 1M9, Canada (I.T.A.)
| | - Stefania Tamburrini
- Department of Radiology, Ospedale del Mare-ASL NA1 Centro, Via Enrico Russo 11, 80147 Naples, Italy
| | - Francesca Iacobellis
- Department of General and Emergency Radiology, A. Cardarelli Hospital, Via A. Cardarelli 9, 80131 Naples, Italy;
| | - Giacomo Sica
- Department of Radiology, Monaldi Hospital, Azienda Ospedaliera dei Colli, 80131 Naples, Italy;
| | - Vincenza Granata
- Division of Radiology, Istituto Nazionale Tumori IRCCS Fondazione Pascale—IRCCS Di Napoli, 80131 Naples, Italy
| | - Luca Saba
- Medical Oncology Department, AOU Cagliari, Policlinico Di Monserrato (CA), 09042 Monserrato, Italy
| | - Salvatore Masala
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Viale S. Pietro, 07100 Sassari, Italy; (S.M.)
| | - Mariano Scaglione
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Viale S. Pietro, 07100 Sassari, Italy; (S.M.)
- Department of Radiology, Pineta Grande Hospital, 81030 Castel Volturno, Italy
- Department of Radiology, James Cook University Hospital, Marton Road, Middlesbrough TS4 3BW, UK
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3
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Browne WF, Sung J, Majdalany BS, Khaja MS, Calligaro K, Contrella BN, Ferencik M, Gunn AJ, Kapoor BS, Keefe NA, Kokabi N, Kramer CM, Kwun R, Shamoun F, Sharma AM, Steenburg SD, Trout AT, Vijay K, Wang DS, Steigner ML. ACR Appropriateness Criteria® Sudden Onset of Cold, Painful Leg: 2023 Update. J Am Coll Radiol 2023; 20:S565-S573. [PMID: 38040470 DOI: 10.1016/j.jacr.2023.08.012] [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: 08/15/2023] [Accepted: 08/22/2023] [Indexed: 12/03/2023]
Abstract
Acute onset of a cold, painful leg, also known as acute limb ischemia, describes the sudden loss of perfusion to the lower extremity and carries significant risk of morbidity and mortality. Acute limb ischemia requires rapid identification and the management of suspected vascular compromise and is inherently driven by clinical considerations. The objectives of initial imaging include confirmation of diagnosis, identifying the location and extent of vascular occlusion, and preprocedural/presurgical planning. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.
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Affiliation(s)
| | - Jeffrey Sung
- Research Author, Weill Cornell Medical College, New York, New York
| | - Bill S Majdalany
- Panel Chair, University of Vermont Medical Center, Burlington, Vermont
| | - Minhaj S Khaja
- Panel Vice-Chair, University of Michigan, Ann Arbor, Michigan
| | - Keith Calligaro
- Pennsylvania Hospital, Philadelphia, Pennsylvania; Society for Vascular Surgery
| | | | - Maros Ferencik
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon; Society of Cardiovascular Computed Tomography
| | - Andrew J Gunn
- University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Nicole A Keefe
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | | | - Christopher M Kramer
- University of Virginia Health, Charlottesville, Virginia; Society for Cardiovascular Magnetic Resonance
| | - Richard Kwun
- Swedish Medical Center, Issaquah, Washington; American College of Emergency Physicians
| | - Fadi Shamoun
- Mayo Clinic Arizona, Phoenix, Arizona; American Society of Echocardiography
| | - Aditya M Sharma
- University of Virginia Health System, Charlottesville, Virginia, Primary care physician
| | - Scott D Steenburg
- Indiana University School of Medicine and Indiana University Health, Indianapolis, Indiana; Committee on Emergency Radiology-GSER
| | - Andrew T Trout
- Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Commission on Nuclear Medicine and Molecular Imaging
| | - Kanupriya Vijay
- University of Texas Southwestern Medical Center, Dallas, Texas
| | - David S Wang
- Stanford University Medical Center, Stanford, California
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Rajiah PS, Kambadakone A, Ananthakrishnan L, Sutphin P, Kalva SP. Vascular Applications of Dual-Energy Computed Tomography. Radiol Clin North Am 2023; 61:1011-1029. [PMID: 37758354 DOI: 10.1016/j.rcl.2023.05.005] [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] [Indexed: 10/03/2023]
Abstract
Dual- or multi-energy CT imaging provides several advantages over conventional CT in the context of vascular imaging. Specific advantages include the use of low-energy virtual monoenergetic images (VMIs) to boost iodine attenuation to salvage suboptimal enhanced studies, perform low-contrast material dose studies, and increase conspicuity of small vessels and lesions. Alternatively, high-energy VMIs reduce artifacts caused by some metals, endoprosthesis, calcium blooming, and beam hardening. Virtual non-contrast (VNC) images reduce radiation dose by eliminating the need for a true non-contrast acquisition in multiphasic CT studies. Iodine maps can be used to evaluate perfusion of tissues and lesions.
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Affiliation(s)
- Prabhakar S Rajiah
- Department of Radiology, Mayo Clinic, 200 1st Street Southwest, Rochester, MN 55905, USA.
| | | | | | - Patrick Sutphin
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Sanjeeva P Kalva
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
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Automatic Plaque Removal Using Dual-Energy Computed Tomography Angiography: Diagnostic Accuracy and Utility in Patients with Peripheral Artery Disease. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58101435. [PMID: 36295595 PMCID: PMC9609865 DOI: 10.3390/medicina58101435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/07/2022] [Accepted: 10/08/2022] [Indexed: 11/17/2022]
Abstract
Background and Objectives: This study aimed to evaluate the utility and accuracy of dual-energy automatic plaque removal (DE-APR) in patients with symptomatic peripheral arterial disease (PAD) using digital subtraction angiography (DSA) as the reference standard. Materials and Methods: We retrospectively analyzed 100 patients with PAD who underwent DE computed tomography angiography (DE-CTA) and DSA of the lower extremities. DE-CTA was used to generate APR subtracted images. In the three main arterial segments (aorto-iliac segment, femoro-popliteal segment, and below-the-knee segment), the presence or absence of hemodynamically significant stenosis (>50%) and calcification was assessed using the images. CTA data were analyzed using different imaging approaches (DE-standard reconstruction image (DE-SR), DE-APR maximum intensity projection image (APR), and DE-SR with APR). Results: For all segments evaluated, the sensitivity, specificity, and accuracy for detecting significant stenosis were 98.16%, 81.01%, and 89.58%, respectively, with DE-SR; 97.79%, 83.33%, and 90.56%, respectively, with APR; and 98.16%, 92.25%, and 95.20%, respectively, with DE-SR with APR. DE-SR with APR had greater accuracy than DE-SR or APR alone (p < 0.001 and p < 0.001, respectively). When analyzed based on vascular wall calcification, the accuracy of DE-SR with APR remained greater than 90% regardless of calcification severity, whereas DE-SR showed a considerable reduction in accuracy in moderate to severe calcification. In the case of APR, the degree of vascular wall calcification did not significantly influence the accuracy in the aorto-iliac and femoro-popliteal segments. DE-SR with APR achieved significantly higher diagnostic accuracy for all lower extremity segments in evaluating hemodynamically significant stenosis in patients with symptomatic PAD and transcended the impact of vascular wall calcification compared with DE-SR. Conclusions: APR demonstrated favorable diagnostic performance in the aorto-iliac and femoro-popliteal segments, exhibiting good agreement with DSA even in cases of moderate to severe vascular wall calcification.
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Kosmala A, Weng AM, Schmid A, Gruschwitz P, Grunz JP, Bley TA, Petritsch B. Dual-Energy CT Angiography in Peripheral Arterial Occlusive Disease: Diagnostic Accuracy of Different Image Reconstruction Approaches. Acad Radiol 2022; 29 Suppl 4:S59-S68. [PMID: 33189548 DOI: 10.1016/j.acra.2020.10.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/03/2020] [Accepted: 10/28/2020] [Indexed: 12/17/2022]
Abstract
OBJECTIVES To evaluate the diagnostic accuracy of five DE-CTA image reconstruction approaches for detection of lower extremity arterial stenosis using digital subtraction angiography as reference standard. METHODS One hundred and eleven patients (63 males; mean age, 75.0 ± 9.7 years) who underwent clinically indicated lower extremity DE-CTA were included in this IRB-approved, HIPAA-compliant retrospective study. Routine multiplanar reconstructions (MPR), curved MPR (cMPR), DE-bone-and-calcified-plaque-subtraction (DE-CS), maximum-intensity projections (MIP), and DE-CS MPR were visually assessed for stenoses > 50%. Automatic objective stenosis grading was implemented on cMPRs. The effect of vessel calcification and luminal contrast on diagnostic performance was evaluated. RESULTS Sensitivity for stenosis detection was high (96.4%-98.6%) with no significant differences among reconstruction approaches. Specificity (74.9%-92.2%) and accuracy (86.9%-94.5%) varied significantly. Pronounced vessel wall calcification and inferior intraluminal contrast attenuation had no significant effect on sensitivity (calcification: p = 0.167 for MPR; 0.567 DE-CS MPR; 0.057 DE-CS MIP; 0.272 cMPR; 0.185 automatic grading; contrast attenuation: p = 1.000 for all reconstructions), but lead to reduced specificity in visual assessment (calcification: p = 0.002 for MPR; <0.001 DE-CS MPR, DE-CS MIP, and cMPR; contrast attenuation: p = 0.844 for MPR; 0.001 DE-CS MPR and DE-CS MIP; 0.420 cMPR). Routine MPR showed highest overall diagnostic performance. CONCLUSION Regardless of image reconstruction approach, vessel calcification and intraluminal contrast attenuation, lower extremity DE-CTA possesses high sensitivity for detection of significant stenoses. Specificity and accuracy vary between reconstruction approaches, indicating the need for additional verification of potential stenotic lesions by use of MPR to reduce the number of unnecessary invasive DSAs due to false-positive CTA findings.
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Rajiah P, Parakh A, Kay F, Baruah D, Kambadakone AR, Leng S. Update on Multienergy CT: Physics, Principles, and Applications. Radiographics 2020; 40:1284-1308. [DOI: 10.1148/rg.2020200038] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Prabhakar Rajiah
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.R., S.L.); Department of Radiology, Massachusetts General Hospital, Boston, Mass (A.P., A.R.K.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (F.K.); and Department of Radiology, Medical University of South Carolina, Charleston, SC (D.B.)
| | - Anushri Parakh
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.R., S.L.); Department of Radiology, Massachusetts General Hospital, Boston, Mass (A.P., A.R.K.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (F.K.); and Department of Radiology, Medical University of South Carolina, Charleston, SC (D.B.)
| | - Fernando Kay
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.R., S.L.); Department of Radiology, Massachusetts General Hospital, Boston, Mass (A.P., A.R.K.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (F.K.); and Department of Radiology, Medical University of South Carolina, Charleston, SC (D.B.)
| | - Dhiraj Baruah
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.R., S.L.); Department of Radiology, Massachusetts General Hospital, Boston, Mass (A.P., A.R.K.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (F.K.); and Department of Radiology, Medical University of South Carolina, Charleston, SC (D.B.)
| | - Avinash R. Kambadakone
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.R., S.L.); Department of Radiology, Massachusetts General Hospital, Boston, Mass (A.P., A.R.K.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (F.K.); and Department of Radiology, Medical University of South Carolina, Charleston, SC (D.B.)
| | - Shuai Leng
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.R., S.L.); Department of Radiology, Massachusetts General Hospital, Boston, Mass (A.P., A.R.K.); Department of Radiology, UT Southwestern Medical Center, Dallas, Tex (F.K.); and Department of Radiology, Medical University of South Carolina, Charleston, SC (D.B.)
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Abstract
Computed tomography angiography (CTA) has become a mainstay for the imaging of vascular diseases, because of high accuracy, availability, and rapid turnaround time. High-quality CTA images can now be routinely obtained with high isotropic spatial resolution and temporal resolution. Advances in CTA have focused on improving the image quality, increasing the acquisition speed, eliminating artifacts, and reducing the doses of radiation and iodinated contrast media. Dual-energy computed tomography provides material composition capabilities that can be used for characterizing lesions, optimizing contrast, decreasing artifact, and reducing radiation dose. Deep learning techniques can be used for classification, segmentation, quantification, and image enhancement.
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Affiliation(s)
- Prabhakar Rajiah
- Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN 55904, USA.
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Oh LCW, Lau KKP, Devapalasundaram A, Buchan K, Kuganesan A, Huynh M. Efficacy of fine focal spot technique in CT angiography of neck. Br J Radiol 2019; 92:20190083. [PMID: 31112401 DOI: 10.1259/bjr.20190083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVES Focal spot size partially defines spatial resolution of a CT system. Many CT tubes have two focal spot sizes, with the finer one allowing more detailed imaging at the cost of photon intensity and increased heat production. Improved X-ray technology and advancement of various generations of iterative reconstruction allow the use of fine focal spot technique in CT angiography. CT neck angiography (CTNA) has been commonly performed as part of stroke imaging or in the trauma setting. This prospective study aimed to assess the efficacy of fine focal spot scanning in vessel clarity improvement, vessel calcification and arterial pulsation artefact reduction on CTNA. METHODS AND MATERIALS Consecutive adult patients of all ages and genders who presented for CTNA were included. All CTNA were scanned with standard focal spot size (SFSS) of 1 × 1 mm in first 4 months while the CTNA in the following 4 months with fine focal spot size (FFSS) of 0.5 × 1 mm. Vessel clarity, calcification and arterial pulsation artefact of arch of aorta, brachiocephalic, subclavian, common carotid, carotid bifurcation, internal carotid, external carotid and vertebral arteries were assessed randomly using a 5-point scale by two blinded radiologists. Results were compared. RESULTS There were 43 patients (mean age 60) with 97 calcified arterial segments in SFSS and 48 patients (mean age 62) with 113 calcified arterial segments in FFSS. 30 % of patients had > 50% carotid artery stenosis. No occlusion or dissection was found in the remaining arteries. Mann-Whitney test showed FFSS performed significantly better for vessel clarity (U: 48238.50, p < .001,r: 0.556) and calcification artefact reduction (U: 2040.50, p < .001,r: 0.564). There was no significant reduction for arterial pulsation artefact. CONCLUSION Fine focal spot technique improves vessel clarity and reduces calcification blooming artefact in CTNA. These benefits may potentially improve the assessment of arterial luminal stenosis and vessel wall pathology, including plaque morphology. ADVANCES IN KNOWLEDGE Beam hardening artefact from calcification particularly in the vessel wall can often reduce the clarity of vessel lumen thus affect accurate assessment of luminal stenosis. Fine focal spot technique has the advantages of reducing beam-hardening artefact of vessel wall calcifications and improving vessel wall clarity, thus it may potentially improve the assessment of arterial luminal stenosis and vessel wall pathology, including plaque morphology. It may become an important CT imaging technique in near future.
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Affiliation(s)
| | - Kenneth Kwok-Pan Lau
- 2 Department of Diagnostic Imaging, Monash Health, Clayton, Victoria, Australia.,3 Department of Medicine, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | | | - Kevin Buchan
- 5 Clinical Science, Philips Healthcare, Mont Albert, Victoria, Australia
| | - Ahilan Kuganesan
- 6 Department of Diagnostic Imaging, Monash Health, Clayton, Victoria, Australia
| | - Minh Huynh
- 7 Department of Statistics Data Science and Epidemiology, Swinburne University of Technology, Hawthorn, Victoria, Australia
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10
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De Santis D, De Cecco CN, Schoepf UJ, Nance JW, Yamada RT, Thomas BA, Otani K, Jacobs BE, Turner DA, Wichmann JL, Eid M, Varga-Szemes A, Caruso D, Grant KL, Schmidt B, Vogl TJ, Laghi A, Albrecht MH. Modified calcium subtraction in dual-energy CT angiography of the lower extremity runoff: impact on diagnostic accuracy for stenosis detection. Eur Radiol 2019; 29:4783-4793. [PMID: 30805703 DOI: 10.1007/s00330-019-06032-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 12/21/2018] [Accepted: 01/22/2019] [Indexed: 01/18/2023]
Abstract
OBJECTIVES To investigate the diagnostic accuracy of a modified three-material decomposition calcium subtraction (CS) algorithm for the detection of arterial stenosis in dual-energy CT angiography (DE-CTA) of the lower extremity runoff compared to standard image reconstruction, using digital subtraction angiography (DSA) as the reference standard. METHODS Eighty-eight patients (53 males; mean age, 65.9 ± 11 years) with suspected peripheral arterial disease (PAD) who had undergone a DE-CTA examination of the lower extremity runoff between May 2014 and May 2015 were included in this IRB-approved, HIPAA-compliant retrospective study. Standard linearly blended and CS images were reconstructed and vascular contrast-to-noise ratios (CNR) were calculated. Two independent observers assessed subjective image quality using a 5-point Likert scale. Diagnostic accuracy for ≥ 50% stenosis detection was analyzed in a subgroup of 45 patients who had undergone additional DSA. Diagnostic accuracy parameters were estimated with a random-effects logistic regression analysis and compared using generalized estimating equations. RESULTS CS datasets showed higher CNR (15.3 ± 7.3) compared to standard reconstructions (13.5 ± 6.5, p < 0.001). Both reconstructions showed comparable qualitative image quality scores (CS, 4.64; standard, 4.57; p = 0.220). Diagnostic accuracy (sensitivity, specificity, positive and negative predictive values) for CS reconstructions was 96.5% (97.5%, 95.6%, 90.9%, 98.1) and 93.1% (98.8%, 90.4%, 82.3%, 99.1%) for standard images. CONCLUSIONS A modified three-material decomposition CS algorithm provides increased vascular CNR, equivalent qualitative image quality, and greater diagnostic accuracy for the detection of significant arterial stenosis of the lower extremity runoff on DE-CTA compared with standard image reconstruction. KEY POINTS • Calcified plaques may lead to overestimation of stenosis severity and false positive results, requiring additional invasive digital subtraction angiography (DSA). • A modified three-material decomposition algorithm for calcium subtraction provides greater diagnostic accuracy for the detection of significant arterial stenosis of the lower extremity runoff compared with standard image reconstruction. • The application of this algorithm in patients with heavily calcified vessels may be helpful to potentially reduce inconclusive CT angiography examinations and the need for subsequent invasive DSA.
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Affiliation(s)
- Domenico De Santis
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA.,Department of Radiological Sciences, Oncology and Pathology, Sant'Andrea University Hospital, "Sapienza" - University of Rome, Rome, Italy
| | - Carlo N De Cecco
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - U Joseph Schoepf
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA.
| | - John W Nance
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - Ricardo T Yamada
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - Brooke A Thomas
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - Katharina Otani
- Imaging and Therapy Systems Division, Healthcare Sector, Siemens Japan K.K., Tokyo, Japan
| | - Brian E Jacobs
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - D Alan Turner
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - Julian L Wichmann
- Division of Experimental and Translational Imaging, Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Marwen Eid
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - Akos Varga-Szemes
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA
| | - Damiano Caruso
- Department of Radiological Sciences, Oncology and Pathology, Sant'Andrea University Hospital, "Sapienza" - University of Rome, Rome, Italy
| | | | - Bernhard Schmidt
- Division of Computed Tomography, Siemens Healthineers, Forchheim, Germany
| | - Thomas J Vogl
- Division of Experimental and Translational Imaging, Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Andrea Laghi
- Department of Radiological Sciences, Oncology and Pathology, Sant'Andrea University Hospital, "Sapienza" - University of Rome, Rome, Italy
| | - Moritz H Albrecht
- Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC, USA.,Division of Experimental and Translational Imaging, Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt am Main, Germany
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11
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Heavily Calcified Coronary Arteries: Advanced Calcium Subtraction Improves Luminal Visualization and Diagnostic Confidence in Dual-Energy Coronary Computed Tomography Angiography. Invest Radiol 2018; 53:103-109. [PMID: 29016370 DOI: 10.1097/rli.0000000000000416] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate a prototype dual-energy computed tomography calcium subtraction algorithm and its impact on luminal visualization in patients with heavily calcified coronary arteries. MATERIALS AND METHODS Twenty-nine patients (62% male; mean age, 64 ± 7 years) who had undergone dual-energy coronary computed tomography angiography were retrospectively included in this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study. Linearly blended (M_0.6) and calcium-subtracted images were reconstructed. Two independent observers assessed luminal visualization of the coronary arteries in a segment-based analysis, subjective image quality, and diagnostic confidence using 5-point Likert scales. Contrast-to-noise ratios for both data sets were calculated. Wilcoxon testing and Cohen's κ were used for statistical comparisons. RESULTS Calcium-subtracted image series showed improved lumen visualization of the coronary arteries (P = 0.008), with excellent interreader agreement (mean score, 3.3; κ = 0.82), compared with M_0.6 series (mean score, 2.9; κ = 0.77). The calcium subtraction algorithm improved diagnostic confidence compared with the M_0.6 reconstructions (mean scores, 4.0 and 3.1, respectively; all P ≤ 0.002). The image quality analysis showed no significant differences between calcium-subtracted and M_0.6 data sets (subjectively: mean scores, 4.1 and 4.2, respectively, P = 0.442; objectively: mean contrast-to-noise ratio, 37.0 and 38.2, respectively, P = 0.733). CONCLUSIONS A prototype algorithm for calcium subtraction improves coronary lumen visualization and diagnostic confidence in patients with heavy coronary calcifications without differences in conventional subjective and objective measures of image quality.
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De Santis D, Eid M, De Cecco CN, Jacobs BE, Albrecht MH, Varga-Szemes A, Tesche C, Caruso D, Laghi A, Schoepf UJ. Dual-Energy Computed Tomography in Cardiothoracic Vascular Imaging. Radiol Clin North Am 2018; 56:521-534. [PMID: 29936945 DOI: 10.1016/j.rcl.2018.03.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Dual energy computed tomography is becoming increasingly widespread in clinical practice. It can expand on the traditional density-based data achievable with single energy computed tomography by adding novel applications to help reach a more accurate diagnosis. The implementation of this technology in cardiothoracic vascular imaging allows for improved image contrast, metal artifact reduction, generation of virtual unenhanced images, virtual calcium subtraction techniques, cardiac and pulmonary perfusion evaluation, and plaque characterization. The improved diagnostic performance afforded by dual energy computed tomography is not associated with an increased radiation dose. This review provides an overview of dual energy computed tomography cardiothoracic vascular applications.
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Affiliation(s)
- Domenico De Santis
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA; Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza", Piazzale Aldo Moro 5, Rome 00185, Italy
| | - Marwen Eid
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA
| | - Carlo N De Cecco
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA
| | - Brian E Jacobs
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA
| | - Moritz H Albrecht
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA; Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany
| | - Akos Varga-Szemes
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA
| | - Christian Tesche
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA; Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Lazarettstraße 36, Munich 80636, Germany
| | - Damiano Caruso
- Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza", Piazzale Aldo Moro 5, Rome 00185, Italy
| | - Andrea Laghi
- Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza", Piazzale Aldo Moro 5, Rome 00185, Italy
| | - Uwe Joseph Schoepf
- Department of Radiology and Radiological Science, Division of Cardiovascular Imaging, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA.
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Peter AC, Schnaubelt M, Gente M. Multispectral X-ray imaging to distinguish among dental materials. Imaging Sci Dent 2017; 47:247-254. [PMID: 29279824 PMCID: PMC5738507 DOI: 10.5624/isd.2017.47.4.247] [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: 09/18/2017] [Revised: 10/26/2017] [Accepted: 11/04/2017] [Indexed: 11/18/2022] Open
Abstract
Purpose Dual-energy X-ray imaging is widely used today in various areas of medicine and in other applications. However, no similar technique exists for dental applications. In this study, we propose a dual-energy technique for dental diagnoses based on voltage-switching. Materials and Methods The method presented in this study allowed different groups of materials to be classified based on atomic number, thereby enabling two-dimensional images to be colorized. Computer simulations showed the feasibility of this approach. Using a number of different samples with typical biologic and synthetic dental materials, the technique was applied to radiographs acquired with a commercially available dental X-ray unit. Results This technique provided a novel visual representation of the intraoral environment in three colors, and is of diagnostic value when compared to state-of-the-art grayscale images, since the oral cavity often contains multiple permanent foreign materials. Conclusion This work developed a technique for two-dimensional dual-energy imaging in the context of dental applications and showed its feasibility with a commercial dental X-ray unit in simulation and experimental studies.
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Affiliation(s)
- Ann-Christin Peter
- Department of Prosthodontics and Orofacial Function, School of Dentistry, Philipps-University Marburg/Lahn, Germany
| | - Matthias Schnaubelt
- Department of Prosthodontics and Orofacial Function, School of Dentistry, Philipps-University Marburg/Lahn, Germany
| | - Michael Gente
- Department of Prosthodontics and Orofacial Function, School of Dentistry, Philipps-University Marburg/Lahn, Germany
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Almutairi A, Al Safran Z, AlZaabi SA, Sun Z. Dual energy CT angiography in peripheral arterial stents: optimal scanning protocols with regard to image quality and radiation dose. Quant Imaging Med Surg 2017; 7:520-531. [PMID: 29184764 DOI: 10.21037/qims.2017.10.07] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Background To determine the optimal scanning protocols of dual energy computed tomography angiography (DECTA) in terms of radiation dose and image quality assessment at different keV levels, and compare it with conventional computed tomography angiography (CTA) in patients treated with peripheral arterial stents. Methods Twenty-nine patients with previous stent placement in peripheral arteries were evaluated with DECTA. Images were reconstructed with virtual monochromatic spectral imaging (VMS) at 65, 68, 70 and 72 keV and adaptive statistical iterative reconstruction (ASIR) at 50% compared with CTA. Image quality comprising image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed, and radiation dose was compared. Effects of different type of peripheral arterial stents on image quality were also evaluated. Fifty-six uniquely identified stents that were located in common iliac arteries (CIA), external iliac arteries (EIA) and superficial femoral arteries (SFA) were evaluated. Results Within subjects, the results showed that DECTA images (VMS) had less noise than the CTA images for CIA, EIA and SFA stents, with the lowest noise at 72 keV. Also, the VMS images had greater SNR than the CTA images for the EIA stents (P<0.05); and the VMS images had greater CNR than the CTA images for CIA, EIA, and SFA stents (P<0.001). Also, on CT attenuation, VMS continued to outperform CTA, but to a lesser extent. Between subjects, average VMS noise varied significantly with the type of the stent used (P=0.025) for CIA stents. Radiation dose was highly significant between DECTA and conventional CTA scans (6.98 vs. 7.40 mSv, P=0.047). Conclusions We conclude that an optimal scanning protocol consisting of 72 keV and 50% ASIR leads to better image quality for DECTA in peripheral arterial stenting when compared to conventional CTA.
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Affiliation(s)
- Abdulrahman Almutairi
- Department of Medical Radiation Sciences, Curtin University, Perth, Western Australia, Australia.,Department of Medical Imaging, King Fahad Specialist Hospital, Dammam, Saudi Arabia
| | - Zakariya Al Safran
- Department of Medical Imaging, King Fahad Specialist Hospital, Dammam, Saudi Arabia
| | - Saif A AlZaabi
- Department of Medical Imaging, King Fahad Specialist Hospital, Dammam, Saudi Arabia
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, Curtin University, Perth, Western Australia, Australia
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Jin KN, Chung JW, Park EA, Lee W. Dual-energy computed tomography angiography: virtual calcified plaque subtraction in a vascular phantom. Acta Radiol Open 2017; 6:2058460117717765. [PMID: 28811929 PMCID: PMC5528944 DOI: 10.1177/2058460117717765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 06/05/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Material decomposition of dual-energy computed tomography (DECT) enables subtraction of calcified plaque. PURPOSE To evaluate the accuracy of lumen area measurement in calcified plaque by subtraction of DECT and to determine the effect of contrast material concentration, lumen diameter, density, and thickness of calcified plaque for the measurement. MATERIAL AND METHODS Vessel phantoms were made with six lumen diameters (5.7, 4.9, 3.9, 3.0, 1.9, and 1.3 mm) and six types of calcified plaques with three densities and two thicknesses were attached. CT scans were performed with three contrast material concentrations (62, 111, and 170 mg iodine/mL). Lumen area discrepancy (AD) was calculated by subtracting the measured lumen area from a reference value. The lumen area underestimation percentage (AU), defined as (AD/reference value) × 100, was calculated. General linear model analysis was used to test the effect of variables for log-transformed AU (ln_AU). RESULTS The AD and AU was calculated to be 6.1 ± 4.8 mm2 and 69.8 ± 29.4%, respectively. Ln_AU was significantly affected by contrast material concentration (P < 0.001), calcium density (P = 0.001), plaque thickness (P = 0.010), and lumen diameter (P < 0.001). Ln_AU was significantly higher in 62 mg iodine/mL than in 111 or 170 mg iodine/mL (P < 0.001 for both). Ln_AU was significantly lower at a lumen diameter of 5.7 mm than 3.9 mm (P = 0.001) or 3.0 (P < 0.001). CONCLUSION Calcified plaque subtraction in DECT substantially underestimates measurements of lumen area. Higher enhancement in larger vessels ensures more accurate subtraction of calcified plaque.
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Affiliation(s)
- Kwang Nam Jin
- Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea
| | - Jin Wook Chung
- Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Eun-Ah Park
- Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Whal Lee
- Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea
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ACR Appropriateness Criteria ® Sudden Onset of Cold, Painful Leg. J Am Coll Radiol 2017; 14:S307-S313. [DOI: 10.1016/j.jacr.2017.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 01/30/2017] [Accepted: 02/02/2017] [Indexed: 11/18/2022]
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Comprehensive Comparison of Virtual Monoenergetic and Linearly Blended Reconstruction Techniques in Third-Generation Dual-Source Dual-Energy Computed Tomography Angiography of the Thorax and Abdomen. Invest Radiol 2016; 51:582-90. [DOI: 10.1097/rli.0000000000000272] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Peripheral artery disease (PAD) has become increasingly common in the US patient population and can be a highly symptomatic and significant source of morbidity. When PAD is suspected, the first-line screening study that is obtained is typically a noninvasive evaluation that includes the ankle brachial index (ABI). Following a positive screening study, invasive catheter digital subtraction angiography (DSA) has been historically used to image the peripheral artery system and still remains the gold standard. However, newer developments in axial imaging including computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have in large part supplanted DSA for imaging the peripheral artery system in clinical practice. Benefits of CTA include rapid noninvasive acquisition, wide availability, high spatial resolution, and the ability to generate isotropic datasets on 64-detector row and higher CT scanners, thereby allowing for multiplanar 3D reformatting. Drawbacks of CTA include the exposure to both iodinated contrast and ionizing radiation, although the radiation dose exposure is lower than for DSA, and newer techniques such as using low tube voltage and rapid acquisition times allow for lower contrast doses. The presence of vascular calcification also limits the evaluation of small distal arteries using CTA, although the development of dual-energy CT techniques has significantly addressed this issue. Benefits of MRA include the avoidance of exposure to ionizing radiation and high diagnostic accuracy, while drawbacks include limited availability and increased cost along with the risk of nephrogenic systemic fibrosis that is associated with gadolinium-based contrast agents, although the latter can be mitigated by using newer non-contrast MR angiography techniques. Future technical advances in CT and MR hardware and software and MR pulse sequences will likely lead to the broader applicability and increased accuracy of noninvasive axial imaging in the evaluation of patients with peripheral artery disease.
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Affiliation(s)
- Nandini M Meyersohn
- Division of Cardiovascular Imaging, Massachusetts General Hospital, Boston, MA, USA,
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Tsukada J, Yamada M, Yamada Y, Yamazaki S, Imanishi N, Tamura K, Hashimoto M, Nakatsuka S, Jinzaki M. Comparison of the diagnostic accuracy of FBP, ASiR, and MBIR reconstruction during CT angiography in the evaluation of a vessel phantom with calcified stenosis in a distal superficial femoral artery in a cadaver extremity. Medicine (Baltimore) 2016; 95:e4127. [PMID: 27399123 PMCID: PMC5058852 DOI: 10.1097/md.0000000000004127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
PURPOSE To investigate whether adaptive statistical iterative reconstruction (ASiR) or model-based iterative reconstruction (MBIR) improves the diagnostic performance of computed tomography angiography (CTA) for small-vessel calcified lesions relative to filtered back projection (FBP) using cadaver extremities and a calcified stenosis phantom. METHODS A cadaver was used in accordance with our institutional regulations, and a calcified stenosis phantom simulating 4 grades of stenosis was prepared. The phantom was inserted within the distal superficial femoral artery of the cadaver leg. Ten CT images per reconstruction type and stenosis grade were acquired using a 64-slice multidetector-row CTA.As an objective measurement, the first and second derivatives of the CT value function profiles were calculated. As a subjective measurement, 2 blinded reviewers measured the stenosis ratio using a quantitative scale. The Wilcoxon rank-sum test was used to evaluate the data. RESULTS Objective measurements of both 25% and 50% stenosis differed significantly (P < 0.01) between MBIR (25/50%: 25.80/50.30 ± 3.88/3.86%) and FBP (25/50%: 35.60/83.80 ± 3.44/26.10%), whereas significant differences were not observed between ASiR and FBP.Reviewer 2's subjective measurements of 25% stenosis differed significantly (P < 0.01) between MBIR (35.13 ± 3.25%) and ASiR (40.89 ± 3.14%), and the measurements of 50% stenosis differed significantly (P < 0.01) between MBIR (reviewers 1/2, 62.36/54.78 ± 2.78/4.96%) and FBP (reviewers 1/2, 62.36/74.84 ± 2.78/18.10%). Significant differences in the subjective measurements were not observed between ASiR and FBP. CONCLUSION MBIR improves the diagnostic performance of CTA for small-vessel calcified lesions relative to FBP.
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Affiliation(s)
- Jitsuro Tsukada
- Department of Diagnostic Radiology, Keio University School of Medicine
| | - Minoru Yamada
- Multi-Dimension Biomedical Imaging and Information Laboratory in Research Park, Keio University School of Medicine
| | - Yoshitake Yamada
- Department of Diagnostic Radiology, Keio University School of Medicine
| | - Shun Yamazaki
- Department of Plastic and Reconstructive Surgery, Keio University School of Medicine
| | - Nobuaki Imanishi
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
| | - Kentaro Tamura
- Department of Diagnostic Radiology, Keio University School of Medicine
| | | | - Seishi Nakatsuka
- Department of Diagnostic Radiology, Keio University School of Medicine
| | - Masahiro Jinzaki
- Department of Diagnostic Radiology, Keio University School of Medicine
- Correspondence: Masahiro Jinzaki, Department of Diagnostic Radiology, Keio University School of Medicine, Tokyo, Japan (e-mail: )
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Cina A, Di Stasi C, Semeraro V, Marano R, Savino G, Iezzi R, Bonomo L. Comparison of CT and MR angiography in evaluation of peripheral arterial disease before endovascular intervention. Acta Radiol 2016; 57:547-56. [PMID: 26185265 DOI: 10.1177/0284185115595657] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 06/20/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND Multidetector computed tomography angiography (MDCTA) and magnetic resonance angiography (MRA) are accurate techniques for selecting patients with peripheral arterial disease for surgical and endovascular treatment. No studies in the literature have directly compared MDCTA and MRA to establish which one should be employed, in patients suitable for both techniques, before endovascular treatment. PURPOSE To compare diagnostic performance of MDCTA vs MRA before endovascular intervention. MATERIAL AND METHODS We prospectively compared MDCTA (64 slices scanner) and MRA (1.5 T scanner; 3D gadolinium-enhanced bolus-chase acquisition plus time resolved acquisition on calves) to stratify 35 patients according to the TASC II score and a runoff severity score. We also evaluated the accuracy of both techniques in each arterial segment. Selective angiography performed during the treatment was the standard of reference. RESULTS MDCTA and MRA accurately classify disease in the aorto-iliac (accuracy 0.92 for MDCTA and MRA) and femoro-popliteal (MDCTA 0.94, MRA 0.90) segments. MDCTA was more accurate in stratifying disease in the infrapopliteal segments (0.96 vs. 0.9) and in assessing the impairment of runoff arteries (0.92 vs. 0.85) at per-segment analysis. MDCTA showed a higher confidence and a shorter examination time. CONCLUSION Our results suggest that MDCTA can be considered as a first-line investigation in patients being candidates for endovascular procedures when clinical history or duplex sonographic evaluation are indicative of severe impairment of the infrapopliteal segment.
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Affiliation(s)
- Alessandro Cina
- Department of Radiological Sciences, “Agostino Gemelli” Hospital, Catholic University, Rome, Italy
| | - Carmine Di Stasi
- Department of Radiological Sciences, “Agostino Gemelli” Hospital, Catholic University, Rome, Italy
| | - Vittorio Semeraro
- Department of Radiological Sciences, “Agostino Gemelli” Hospital, Catholic University, Rome, Italy
| | - Riccardo Marano
- Department of Radiological Sciences, “Agostino Gemelli” Hospital, Catholic University, Rome, Italy
| | - Giancarlo Savino
- Department of Radiological Sciences, “Agostino Gemelli” Hospital, Catholic University, Rome, Italy
| | - Roberto Iezzi
- Department of Radiological Sciences, “Agostino Gemelli” Hospital, Catholic University, Rome, Italy
| | - Lorenzo Bonomo
- Department of Radiological Sciences, “Agostino Gemelli” Hospital, Catholic University, Rome, Italy
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Schabel C, Bongers MN, Ketelsen D, Syha R, Thomas C, Homann G, Notohamiprodjo M, Nikolaou K, Bamberg F. [Diagnostic accuracy of dual energy CT angiography in patients with diabetes mellitus]. Radiologe 2016; 55:314-22. [PMID: 25809927 DOI: 10.1007/s00117-014-2721-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVES Peripheral arterial disease (PAD) represents a major and highly prevalent complication in patients with diabetes mellitus. The diagnostic, non-invasive work-up by computed tomography angiography (CTA) is limited in the presence of extensive calcification. The aim of the study was to determine the diagnostic accuracy of dual energy CTA (DE-CTA) for the detection and characterization of PAD in patients with diabetes mellitus. MATERIAL AND METHODS In this study 30 diabetic patients with suspected or known PAD were retrospectively included in the analysis. All subjects underwent DE-CTA (Somatom Definition Flash, Siemens Healthcare, Erlangen, Germany) prior to invasive angiography, which served as the reference standard. Blinded analysis included assessment of the presence and degree of peripheral stenosis on curved multiplanar reformatting (MPR) and maximum intensity projections (MIP). Conventional measures of diagnostic accuracy were derived. RESULTS Among the 30 subjects included in the analysis (83% male, mean age 70.0 ± 10.5 years, 83% diabetes type 2), the prevalence of critical stenosis in 331 evaluated vessel segments was high (30%). Dual energy CT identified critical stenoses with a high sensitivity and good specificity using curved MPR (100% and 93.1%, respectively) and MIP images (99% and 91.8%, respectively). In stratified analysis, the diagnostic accuracy was higher for stenosis pertaining to the pelvic and thigh vessels as compared with the lower extremities (curved MPR accuracy 97.1% vs. 99.2 vs. 90.9%; respectively, p < 0.001). CONCLUSION The use of DE-CTA allows reliable detection and characterization of peripheral arterial stenosis in patients with diabetes mellitus with higher accuracy in vessels in the pelvic and thigh regions compared with the vessels in the lower legs.
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Affiliation(s)
- C Schabel
- Abteilung für Diagnostische und Interventionelle Radiologie, Klinikum der Eberhard-Karls-Universität, Hoppe-Seyler-Str. 3, 72076, Tübingen, Deutschland,
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McCollough CH, Leng S, Yu L, Fletcher JG. Dual- and Multi-Energy CT: Principles, Technical Approaches, and Clinical Applications. Radiology 2015; 276:637-53. [PMID: 26302388 DOI: 10.1148/radiol.2015142631] [Citation(s) in RCA: 947] [Impact Index Per Article: 105.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In x-ray computed tomography (CT), materials having different elemental compositions can be represented by identical pixel values on a CT image (ie, CT numbers), depending on the mass density of the material. Thus, the differentiation and classification of different tissue types and contrast agents can be extremely challenging. In dual-energy CT, an additional attenuation measurement is obtained with a second x-ray spectrum (ie, a second "energy"), allowing the differentiation of multiple materials. Alternatively, this allows quantification of the mass density of two or three materials in a mixture with known elemental composition. Recent advances in the use of energy-resolving, photon-counting detectors for CT imaging suggest the ability to acquire data in multiple energy bins, which is expected to further improve the signal-to-noise ratio for material-specific imaging. In this review, the underlying motivation and physical principles of dual- or multi-energy CT are reviewed and each of the current technical approaches is described. In addition, current and evolving clinical applications are introduced.
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Affiliation(s)
- Cynthia H McCollough
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Shuai Leng
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Lifeng Yu
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Joel G Fletcher
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905
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Almutairi A, Sun Z, Poovathumkadavi A, Assar T. Dual Energy CT Angiography of Peripheral Arterial Disease: Feasibility of Using Lower Contrast Medium Volume. PLoS One 2015; 10:e0139275. [PMID: 26418007 PMCID: PMC4587806 DOI: 10.1371/journal.pone.0139275] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/09/2015] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVE One of the main drawbacks associated with Dual Energy Computed Tomography Angiography (DECTA) is the risk of developing contrast medium-induced nephropathy (CIN). The aim of the present study was firstly, to design an optimal CT imaging protocol by determining the feasibility of using a reduced contrast medium volume in peripheral arterial DECTA, and secondly, to compare the results with those obtained from using routine contrast medium volume. METHODS Thirty four patients underwent DECTA for the diagnosis of peripheral arterial disease. They were randomly divided into two groups: Group 1 (routine contrast volume group) with n = 17, injection rate 4-5 ml/s, and 1.5 ml/kg of contrast medium, and Group 2 ((low contrast volume group), with n = 17, injection rate 4-5ml/s, and contrast medium volume 0.75 ml/kg. A fast kilovoltage-switching 64-slice CT scanner in the dual-energy mode was employed for the study. A total of 6 datasets of monochromatic images at 50, 55, 60, 65, 70 and 75 keV levels were reconstructed with adaptive statistical iterative reconstruction (ASIR) at 50%. A 4-point scale was the tool for qualitative analysis of results. The two groups were compared and assessed quantitatively for image quality on the basis of signal-to-noise ratio (SNR) and contrast-to-noise-ratio (CNR). Radiation and contrast medium doses were also compared. RESULTS The overall mean CT attenuation and mean noise for all lower extremity body parts was significantly lower for the low volume contrast group (p<0.001), and varied significantly between groups (p = 0.001), body parts (p<0.001) and keVs (p<0.001). The interaction between group body parts was significant with CT attenuation and CNR (p = 0.002 and 0.003 respectively), and marginally significant with SNR (p = 0.047), with minimal changes noticed between the two groups. Group 2 (low contrast volume group) displayed the lowest image noise between 65 and 70 keV, recorded the highest SNR and CNR at 65 keV, and produced significantly lower results with respect to contrast medium volume and duration of contrast injection (p<0.001). The effect of radiation dose was not statistically significant between the two groups. CONCLUSIONS DECTA images created at 65 keV and 50% ASIR with low contrast medium volume protocol, yielded results that were comparable to routine contrast medium volume, with acceptable diagnostic images produced during the evaluation of peripheral arteries.
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Affiliation(s)
- Abdulrahman Almutairi
- Department of Medical Radiation Sciences, School of Science, Curtin University, Perth, 6845, Western Australia, Australia
- Department of Medical Imaging, King Fahad Specialist Hospital, Dammam, 31444, Saudi Arabia
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, School of Science, Curtin University, Perth, 6845, Western Australia, Australia
- * E-mail:
| | | | - Tarek Assar
- Department of Medical Imaging, King Fahad Specialist Hospital, Dammam, 31444, Saudi Arabia
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Kuchenbecker S, Faby S, Sawall S, Lell M, Kachelrieß M. Dual energy CT: how well can pseudo-monochromatic imaging reduce metal artifacts? Med Phys 2015; 42:1023-36. [PMID: 25652515 DOI: 10.1118/1.4905106] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Dual Energy CT (DECT) provides so-called monoenergetic images based on a linear combination of the original polychromatic images. At certain patient-specific energy levels, corresponding to certain patient- and slice-dependent linear combination weights, e.g., E = 160 keV corresponds to α = 1.57, a significant reduction of metal artifacts may be observed. The authors aimed at analyzing the method for its artifact reduction capabilities to identify its limitations. The results are compared with raw data-based processing. METHODS Clinical DECT uses a simplified version of monochromatic imaging by linearly combining the low and the high kV images and by assigning an energy to that linear combination. Those pseudo-monochromatic images can be used by radiologists to obtain images with reduced metal artifacts. The authors analyzed the underlying physics and carried out a series expansion of the polychromatic attenuation equations. The resulting nonlinear terms are responsible for the artifacts, but they are not linearly related between the low and the high kV scan: A linear combination of both images cannot eliminate the nonlinearities, it can only reduce their impact. Scattered radiation yields additional noncanceling nonlinearities. This method is compared to raw data-based artifact correction methods. To quantify the artifact reduction potential of pseudo-monochromatic images, they simulated the FORBILD abdomen phantom with metal implants, and they assessed patient data sets of a clinical dual source CT system (100, 140 kV Sn) containing artifacts induced by a highly concentrated contrast agent bolus and by metal. In each case, they manually selected an optimal α and compared it to a raw data-based material decomposition in case of simulation, to raw data-based material decomposition of inconsistent rays in case of the patient data set containing contrast agent, and to the frequency split normalized metal artifact reduction in case of the metal implant. For each case, the contrast-to-noise ratio (CNR) was assessed. RESULTS In the simulation, the pseudo-monochromatic images yielded acceptable artifact reduction results. However, the CNR in the artifact-reduced images was more than 60% lower than in the original polychromatic images. In contrast, the raw data-based material decomposition did not significantly reduce the CNR in the virtual monochromatic images. Regarding the patient data with beam hardening artifacts and with metal artifacts from small implants the pseudo-monochromatic method was able to reduce the artifacts, again with the downside of a significant CNR reduction. More intense metal artifacts, e.g., as those caused by an artificial hip joint, could not be suppressed. CONCLUSIONS Pseudo-monochromatic imaging is able to reduce beam hardening, scatter, and metal artifacts in some cases but it cannot remove them. In all cases, the CNR is significantly reduced, thereby rendering the method questionable, unless special post processing algorithms are implemented to restore the high CNR from the original images (e.g., by using a frequency split technique). Raw data-based dual energy decomposition methods should be preferred, in particular, because the CNR penalty is almost negligible.
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Affiliation(s)
| | - Sebastian Faby
- German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Stefan Sawall
- German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Michael Lell
- Friedrich-Alexander-University (FAU), Erlangen 91054, Germany
| | - Marc Kachelrieß
- German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
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Remer EM, Papanicolaou N, Casalino DD, Bishoff JT, Blaufox MD, Coursey CA, Dighe M, Eberhardt SC, Goldfarb S, Harvin HJ, Heilbrun ME, Leyendecker JR, Nikolaidis P, Oto A, Preminger GM, Raman SS, Sheth S, Vikram R, Weinfeld RM. ACR Appropriateness Criteria(®) on renal failure. Am J Med 2014; 127:1041-1048.e1. [PMID: 24865874 DOI: 10.1016/j.amjmed.2014.05.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 05/07/2014] [Accepted: 05/07/2014] [Indexed: 10/25/2022]
Abstract
Imaging plays a role in the management of patients with acute kidney injury or chronic kidney disease. However, clinical circumstances strongly impact the appropriateness of imaging use. In patients with newly detected renal dysfunction, ultrasonography can assess for reversible causes, assess renal size and echogenicity, and thus, establish the chronicity of disease. Urinary obstruction can be detected, but imaging is most useful in high-risk groups or in patients in whom there is a strong clinical suspicion for obstruction. Computed tomography, computed tomography or magnetic resonance arteriography, and percutaneous ultrasound-guided renal biopsy are valuable in other clinical situations. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
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Swanberg J, Nyman R, Magnusson A, Wanhainen A. Selective Intra-arterial Dual-energy CT Angiography (s-CTA) in Lower Extremity Arterial Occlusive Disease. Eur J Vasc Endovasc Surg 2014; 48:325-9. [DOI: 10.1016/j.ejvs.2014.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 05/13/2014] [Indexed: 10/25/2022]
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Oh LCW, Lau KK, Devapalasundaram A, Buchan K, Ardley N, Huynh M. Efficacy of 'fine' focal spot imaging in CT abdominal angiography. Eur Radiol 2014; 24:3010-6. [PMID: 25097134 DOI: 10.1007/s00330-014-3368-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/26/2014] [Accepted: 07/21/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To assess the efficacy of fine focal spot imaging in calcification beam-hardening artefact reduction and vessel clarity on CT abdominal angiography (CTAA). METHODS Adult patients of any age and gender who presented for CTAA were included. Thirty-nine patients were examined with a standard focal spot size (SFSS) of 1 × 1 mm in the first 3 months while 31 consecutive patients were examined with a fine focal spot size (FFSS) of 1 × 0.5 mm in the following 3 months. Vessel clarity and calcification beam-hardening artefacts of the abdominal aorta, celiac axis, superior mesenteric artery, inferior mesenteric artery, renal arteries, and iliac arteries were assessed using a 5-point grading scale by two blinded radiologists randomly. RESULTS Cohen's Kappa test indicated that on average, there was substantial agreement among reviewers for vessel wall clarity and calcification artefact grading. Mann-Whitney test showed that there was a significant difference between the two groups, with FFSS performing significantly better for vessel clarity (U, 6481.50; p < 0.001; r, 0.73) and calcification artefact reduction (U, 1916; p < 0.001; r, 0.77). CONCLUSION Fine focus CT angiography produces images with better vessel wall clarity and less vessel calcification beam-hardening artefact. KEY POINTS Focal spot size affects the spatial resolution of a CT system. Fine focus CTAA produces images with improved vessel wall clarity. Fine focus CTAA is associated with fewer calcification beam-hardening artefacts. Fine focus CTAA may improve accuracy in assessment of luminal stenosis.
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Affiliation(s)
- Lawrence Chia Wei Oh
- Department of Diagnostic Imaging, Monash Health, 246 Clayton Road, Clayton, 3168, Victoria, Australia,
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Sudarski S, Apfaltrer P, Nance JW, Schneider D, Meyer M, Schoenberg SO, Fink C, Henzler T. Optimization of keV-settings in abdominal and lower extremity dual-source dual-energy CT angiography determined with virtual monoenergetic imaging. Eur J Radiol 2013; 82:e574-81. [PMID: 23763858 DOI: 10.1016/j.ejrad.2013.04.040] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/22/2013] [Accepted: 04/23/2013] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To compare objective image quality indices in dual-energy CT angiography (DE-CTA) studies of the abdomen and lower extremity using conventional polyenergetic images (PEIs) and virtual monoenergetic images (MEIs) at different kiloelectron volt (keV) levels. METHODS We retrospectively evaluated 68 dual-source DE-CTA studies. 50 patients (42 men, 71 ± 10 years) underwent abdominal DE-CTA. 18 patients (13 men, 67 ± 10 years) underwent lower extremity DE-CTA. MEIs from 40 to 120 keV were reconstructed. Signal intensity, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed in infrarenal aorta, superior mesenteric, external iliac, femoral, popliteal, and lower leg arteries. Comparisons between MEIs and PEIs were performed with Dunnett's test. RESULTS 222 arteries were evaluated. In abdominal arteries 70 keV MEIs showed statistically equal signal intensity, noise and CNR levels (+13%; +31%, -14% on average; all p>0.05) compared to PEIs; SNR was equal or slightly impaired (-7% on average; p<0.001-1.00). In lower extremity arteries 60 keV MEIs resulted in significantly higher signal intensity and CNR (+54%; +54% on average; all p<0.05) compared to PEIs at equal noise levels (+18% on average; all p>0.05) and equal or higher SNR (+49% on average; p<0.01-0.35). CONCLUSIONS Low-keV MEIs lead to equal or higher signal intensity and CNR compared to PEIs. In lower extremity DE-CTA, additional reconstruction of low-keV MEIs at 60 keV might increase diagnostic confidence.
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Affiliation(s)
- Sonja Sudarski
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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Welman CJ, Harrison C, Low RS. Contrast-enhanced magnetic resonance angiography of the peripheral arteries: technique, tips, pitfalls and problems. J Med Imaging Radiat Oncol 2013; 57:125-40. [PMID: 23551769 DOI: 10.1111/1754-9485.12027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 10/02/2012] [Indexed: 11/30/2022]
Abstract
Contrast-enhanced magnetic resonance angiography is a reliable way to assess peripheral vascular disease. This article reviews the basic physics behind this technique and discusses our institution's experience with regard to the clinical role, recent advances in image acquisition and use of contrast agents. Problems that can affect image quality and interpretation are also highlighted.
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Affiliation(s)
- Christopher J Welman
- Department of Radiology, Fremantle Hospital and Health Service, Fremantle, Western Australia, Australia
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Young PM, Mostardi PM, Glockner JF, Vrtiska TR, Macedo T, Haider CR, Riederer SJ. Prospective comparison of cartesian acquisition with projection-like reconstruction magnetic resonance angiography with computed tomography angiography for evaluation of below-the-knee runoff. J Vasc Interv Radiol 2013; 24:392-9. [PMID: 23433414 PMCID: PMC3593305 DOI: 10.1016/j.jvir.2012.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 11/05/2012] [Accepted: 11/08/2012] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To compare prospectively the assessment of stenosis and radiologist confidence in the evaluation of below-the-knee lower extremity runoff vessels between computed tomography (CT) angiography and contrast-enhanced magnetic resonance (MR) angiography in a cohort of 19 clinical patients. MATERIALS AND METHODS The study was compliant with the Health Insurance Portability and Accountability Act of 1996 and approved by the institutional review board. Imaging was performed in 19 consecutive patients with known or suspected peripheral arterial disease; both CT angiography and a more recently developed MR angiography technique were performed within 24 hours of each other and before any therapeutic intervention. Resulting images were randomized and interpreted in blinded fashion by four board-certified radiologists with expertise in CT angiography and MR angiography. Vasculature of the lower leg was apportioned into 22 segments, 11 for each leg. For each segment, degree of stenosis and confidence of diagnosis were determined using a 3-point scale. Differences between CT angiography and MR angiography were assessed for significance using pooled histograms that were analyzed using the Wilcoxon signed rank test. RESULTS For assessment of stenosis, there was no difference in CT angiography compared with MR angiography for 20 of 22 segments. For confidence of diagnosis, assessment of popliteal arteries was superior on CT angiography compared with MR angiography (P<.05). Confidence in assessment of both tibioperoneal trunks and the left proximal anterior tibial artery was not significantly different between CT angiography and MR angiography. Confidence in assessment of all other 17 segments was superior with MR angiography compared with CT angiography (P<.02). CONCLUSIONS MR angiography using the method described here is a promising technique for evaluating lower extremity arterial runoff. MR angiography had an overall superior performance in radiologist confidence compared with CT angiography for imaging runoff vessels below the knee.
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Affiliation(s)
- Phillip M Young
- Department of Radiology, Mayo Clinic, Mayo 2, 200 First Street SW, Rochester, MN 55905, USA.
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Automatic bone removal technique in whole-body dual-energy CT angiography: performance and image quality. AJR Am J Roentgenol 2013; 199:W646-50. [PMID: 23096210 DOI: 10.2214/ajr.12.9176] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the efficiency of automatic bone removal in dual-energy CT angiography (CTA) of the trunk. SUBJECTS AND METHODS Nineteen patients underwent dual-energy CTA of the trunk (tube A, 140 kV; tube B, 100 kV). In addition to the dual-energy dataset, an image equivalent to that of a standard 120-kV single-energy examination was generated with both tubes. Automated bone segmentation was performed on both datasets, and the results were analyzed. The time required for and subjective image quality of the maximum intensity projections (MIPs) generated were evaluated. RESULTS Errors in bone segmentation were found for 1.5% of bones on dual-energy images and 12.4% of bones on single-energy images (p < 0.01). The most important differences were found in the rib cage, sternum, and pelvis. The times required for postprocessing of MIPs were similar for the dual-energy (113.5 seconds) and single-energy (106.8 seconds) techniques. The subjective image quality of the arteries was considered better for dual-energy CTA (4.5 points) than for single-energy CTA (4.1 points) owing to false cutoff of vessels during the bone removal process on the single-energy images (p = 0.026). CONCLUSION For CTA of the trunk, the dual-energy postprocessing capabilities for 3D visualization are superior to the threshold-based bone removal of single-energy CT. Dual-energy CTA can generate boneless MIP images of substantial quality.
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Abstract
OBJECTIVE Dual-energy CT permits a variety of image reconstructions for the depiction and characterization of vascular disease. Techniques include visualization of low- and high-peak-kilovoltage spectra image datasets and also material-specific reconstructions combining both low- and high-peak-kilovoltage data. CONCLUSION This article focuses on four main vascular areas: the aorta, the major visceral, lower limb, and cervical arteries. For each territory, the current status, potential advantages, and limitations of these techniques are described.
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Krissak R, Elgert M, Kusch B, Hünerbein R. Gold as a Potential Contrast Agent for Dual-Energy CT. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ami.2013.34006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
One of the main problems in coronary angiography using 64-row computed tomography (CT) is that the presence of severe calcification interferes with the assessment of lesions, which reduces diagnostic accuracy and may even make assessment of some coronary artery segments impossible. With 320-row CT, it is possible to avoid this problem by performing subtraction coronary CT, which fully exploits the performance capabilities of the CT system. However, subtraction coronary CT has several limitations. When these limitations have been overcome, this technique is expected to become a useful method for assessing patients with severe calcification and evaluating coronary artery stents.
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Affiliation(s)
- Kunihiro Yoshioka
- Division of Cardiovascular Radiology, Department of Radiology, Iwate Medical University Hospital, 19-1 Uchimaru, Morioka 020-8505, Japan.
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Subtraction Coronary CT Angiography for the Evaluation of Severely Calcified Lesions Using a 320-Detector Row Scanner. CURRENT CARDIOVASCULAR IMAGING REPORTS 2011. [DOI: 10.1007/s12410-011-9108-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Lee IJ, Chung JW, Hong H, Yin YH, Kim S, Park EA, Lee W. Subtraction CT angiography of the lower extremities: single volume subtraction versus multi-segmented volume subtraction. Acad Radiol 2011; 18:902-9. [PMID: 21420330 DOI: 10.1016/j.acra.2011.01.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/26/2011] [Accepted: 01/27/2011] [Indexed: 11/18/2022]
Abstract
RATIONALE AND OBJECTIVES To validate the hypothesis that a multisegmented approach during subtraction computed tomography (CT) angiography of the lower extremities can improve bone removal efficiency by suppressing regional motion. MATERIALS AND METHODS The institutional review board of our hospital approved this retrospective study. One hundred and one consecutive patients that had undergone the lower extremity CT angiography were included in this study. Subtraction CT angiography was performed using two different methods, namely, by single volume subtraction and by multisegmented volume subtraction. Multisegmented volume subtraction was conducted by dividing the whole volume of the CT data into three segments along the z axis of the lower extremities, performing a subtraction process for each segment, and combining segments to form as single subtracted volume. The bone removal efficiencies of the two methods was assessed by analyzing bone subtraction scores on maximum intensity projection (MIP) images for each bone segment in a blinded fashion. In addition, overall MIP image qualities were compared by displaying MIP images produced using the two methods side by side. Differences between bone subtraction scores were tested using Wilcoxon's signed rank test. RESULTS Multisegmented volume subtraction MIP images demonstrated significantly better bone removal for the following bone segments: pelvis (P < .0001), hip (P = .0002), thigh (P = .0258), knee (P = .0004), ankle (P = .0008), metatarsal bone (P < .0001), and toes (P < .0001). Overall bone subtraction score and subjective image qualities determined by performing side-by-side comparisons were better for the multisegmented volume subtraction method. CONCLUSION Bone removal performance and overall MIP image quality can be increased by adopting multisegmented volume subtraction during subtraction CT angiography of the lower extremities.
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Affiliation(s)
- In Joon Lee
- Department of Radiology, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul National University Medical Research Center, Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul, 110-744
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Kawai T, Shibamoto Y, Hara M, Arakawa T, Nagai K, Ohashi K. Can dual-energy CT evaluate contrast enhancement of ground-glass attenuation? Phantom and preliminary clinical studies. Acad Radiol 2011; 18:682-9. [PMID: 21393031 DOI: 10.1016/j.acra.2010.12.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 12/24/2010] [Accepted: 12/27/2010] [Indexed: 12/20/2022]
Abstract
RATIONALE AND OBJECTIVES Evaluation of contrast enhancement of pulmonary lesions with ground-glass attenuation (GGA) is difficult with conventional techniques but might be possible using contrast-mapping images (CMIs) obtained by dual-energy computed tomography. To address this issue, a phantom study was conducted, and this technique was then applied to clinical cases. MATERIALS AND METHODS Phantoms made of agarose gel and those made of hollow resin clay, containing various concentrations of iodine or calcium, were used to simulate soft tissue and GGA, respectively. They were scanned using a dual-energy computed tomographic scanner, and the relationship between iodine concentration and calculated iodine value on CMIs was examined. The influence of calcium was also evaluated. In addition, contrast enhancement of 24 GGA lesions was evaluated on CMIs. RESULTS There was a good correlation between iodine value and iodine concentration in the soft-tissue models (r(2) = 0.996). In the GGA models, the former tended to exceed the latter when default parameters for calculating CMIs were used, but this could be corrected by modifying the parameters (r(2) = 0.998). The iodine value increased with calcium concentration in both models. On CMIs, contrast enhancement was visible in 22 adenocarcinomas but not in a pulmonary hemorrhage and an inflammatory change. CONCLUSIONS Dual-energy computed tomography can evaluate contrast enhancement of GGA lesions.
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Lau JF, Weinberg MD, Olin JW. Peripheral artery disease. Part 1: clinical evaluation and noninvasive diagnosis. Nat Rev Cardiol 2011; 8:405-18. [PMID: 21629211 DOI: 10.1038/nrcardio.2011.66] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Peripheral artery disease (PAD) is a marker of systemic atherosclerosis. Most patients with PAD also have concomitant coronary artery disease (CAD), and a large burden of morbidity and mortality in patients with PAD is related to myocardial infarction, ischemic stroke, and cardiovascular death. PAD patients without clinical evidence of CAD have the same relative risk of death from cardiac or cerebrovascular causes as those diagnosed with prior CAD, consistent with the systemic nature of the disease. The same risk factors that contribute to CAD and cerebrovascular disease also lead to the development of PAD. Because of the high prevalence of asymptomatic disease and because only a small percentage of PAD patients present with classic claudication, PAD is frequently underdiagnosed and thus undertreated. Health care providers may have difficulty differentiating PAD from other diseases affecting the limb, such as arthritis, spinal stenosis or venous disease. In Part 1 of this Review, we explain the epidemiology of and risk factors for PAD, and discuss the clinical presentation and diagnostic evaluation of patients with this condition.
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Affiliation(s)
- Joe F Lau
- The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1033, New York, NY 10029-6574, USA
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Kau T, Eicher W, Reiterer C, Niedermayer M, Rabitsch E, Senft B, Hausegger KA. Dual-energy CT angiography in peripheral arterial occlusive disease—accuracy of maximum intensity projections in clinical routine and subgroup analysis. Eur Radiol 2011; 21:1677-86. [DOI: 10.1007/s00330-011-2099-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 01/29/2011] [Indexed: 11/30/2022]
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Automatic bone removal dual-energy CT angiography for the evaluation of intracranial aneurysms. J Comput Assist Tomogr 2011; 34:816-24. [PMID: 21084894 DOI: 10.1097/rct.0b013e3181eff93c] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the diagnostic accuracy of dual-energy computed tomographic angiography (DE-CTA) in the detection of intracranial aneurysms and to determine whether DE-CTA provides adequate information to guide treatment choice. MATERIALS AND METHODS Eighty patients (31 men and 49 women; mean [SD] ages of 52 [9] years) with spontaneous subarachnoid hemorrhage underwent DE-CTA. The performance of DE-CTA was compared with conventional CTA created from average weighted images and digital subtraction angiography (DSA). Sensitivity and specificity for aneurysm detection were determined on a per-patient and per-aneurysm basis. The treatment choice was assessed on the basis of aneurysm neck size and/or the dome/neck ratio. RESULTS With DSA as reference standard (n = 61; 47 aneurysms in 41 patients), DE-CTA correctly detected 45 aneurysms in 41 patients corresponding to sensitivity and specificity of 100% and 95.0% on a per-patient basis versus 95.7% and 95.0% on a per-aneurysm basis, whereas conventional CTA correctly detected 43 aneurysms in 39 patients corresponding to sensitivity and specificity of 95.1% and 95.0% on a per-patient basis versus 91.5% and 95.0% on a per-aneurysm basis. No statistical difference between DE-CTA and conventional CTA was found for the diagnostic evaluation of intracranial aneurysms. Surgery was performed to treat 38 aneurysms, coiling in 26 aneurysms, stent in one patient, and follow-up in the remaining 5 aneurysms. Dual-energy CTA correctly predicted treatment choice in 44 aneurysms, with 15 aneurysms coiled and 29 aneurysms clipped. CONCLUSIONS Compared with DSA, DE-CTA had a comparable diagnostic accuracy for the detection of intracranial aneurysms, visualization of the morphology of aneurysms at the skull base, and prediction of aneurysm treatment choice in most patients with spontaneous subarachnoid hemorrhage based on this study.
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Keeling AN, Farrelly C, Carr JC, Yaghmai V. Technical considerations for lower limb multidetector computed tomographic angiography. Vasc Med 2010; 16:131-43. [PMID: 21138985 DOI: 10.1177/1358863x10388347] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Multidetector computed tomography (MDCT) enables imaging of the entire arterial tree non-invasively. Optimal technical considerations for performing MDCT angiography (MDCTA) are essential for accurate diagnosis and atherosclerotic disease stratification. This review article focuses on the various technical aspects necessary for peripheral computed tomographic angiography (CTA) acquisition. Common clinical indications for peripheral MDCTA and the latest scan protocols are described. The essential issue of radiation dose reduction is discussed, along with methods of optimal contrast bolus detection and delivery. Post-processing techniques are also presented. Previously, digital subtraction angiography was the only established reliable imaging technique to quantify atherosclerotic disease load; however, MDCTA may now challenge this old gold standard, along with other non-invasive techniques such as magnetic resonance angiography (MRA).
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Affiliation(s)
- Aoife N Keeling
- Department of Radiology, Division of Cardiovascular Imaging, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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Dual-source dual-energy CT with additional tin filtration: Dose and image quality evaluation in phantoms and in vivo. AJR Am J Roentgenol 2010; 195:1164-74. [PMID: 20966323 DOI: 10.2214/ajr.09.3956] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of this study was to investigate the effect on radiation dose and image quality of the use of additional spectral filtration for dual-energy CT using dual-source CT (DSCT). MATERIALS AND METHODS A commercial DSCT scanner was modified by adding tin filtration to the high-kV tube, and radiation output and noise were measured in water phantoms. Dose values for equivalent image noise were compared between the dual-energy mode with and without tin filtration and the single-energy mode. To evaluate dual-energy CT material discrimination, the material-specific dual-energy ratio for calcium and that for iodine were determined using images of anthropomorphic phantoms. Data were additionally acquired from imaging a 38-kg pig and an 87-kg pig, and the noise of the linearly mixed images and virtual noncontrast images was compared between dual-energy modes. Finally, abdominal dual-energy CT images of two patients of similar sizes undergoing clinically indicated CT were compared. RESULTS Adding tin filtration to the high-kV tube improved the dual-energy contrast between iodine and calcium as much as 290%. Data from our animal study showed that tin filtration had no effect on noise in the dual-energy CT mixed images but decreased noise by as much as 30% in the virtual noncontrast images. Virtual noncontrast images of patients acquired using 100 and 140 kV with added tin filtration had improved image quality relative to those generated using 80 and 140 kV without tin filtration. CONCLUSION Tin filtration of the high-kV tube of a DSCT scanner increases the ability of dual-energy CT to discriminate between calcium and iodine without increasing dose relative to single-energy CT. Furthermore, the use of 100- and 140-kV tube potentials allows improved dual-energy CT imaging of large patients.
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Coursey CA, Nelson RC, Boll DT, Paulson EK, Ho LM, Neville AM, Marin D, Gupta RT, Schindera ST. Dual-energy multidetector CT: how does it work, what can it tell us, and when can we use it in abdominopelvic imaging? Radiographics 2010; 30:1037-55. [PMID: 20631367 DOI: 10.1148/rg.304095175] [Citation(s) in RCA: 259] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Dual-energy CT provides information about how substances behave at different energies, the ability to generate virtual unenhanced datasets, and improved detection of iodine-containing substances on low-energy images. Knowing how a substance behaves at two different energies can provide information about tissue composition beyond that obtainable with single-energy techniques. The term K edge refers to the spike in attenuation that occurs at energy levels just greater than that of the K-shell binding because of the increased photoelectric absorption at these energy levels. K-edge values vary for each element, and they increase as the atomic number increases. The energy dependence of the photoelectric effect and the variability of K edges form the basis of dual-energy techniques, which may be used to detect substances such as iodine, calcium, and uric acid crystals. The closer the energy level used in imaging is to the K edge of a substance such as iodine, the more the substance attenuates. In the abdomen and pelvis, dual-energy CT may be used in the liver to increase conspicuity of hypervascular lesions; in the kidneys, to distinguish hyperattenuating cysts from enhancing renal masses and to characterize renal stone composition; in the adrenal glands, to characterize adrenal nodules; and in the pancreas, to differentiate between normal and abnormal parenchyma.
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Affiliation(s)
- Courtney A Coursey
- Department of Radiology, Duke University Medical Center, Durham, NC, USA.
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Knöss N, Hoffmann B, Krauss B, Heller M, Biederer J. Dual energy computed tomography of lung nodules: differentiation of iodine and calcium in artificial pulmonary nodules in vitro. Eur J Radiol 2010; 80:e516-9. [PMID: 21112712 DOI: 10.1016/j.ejrad.2010.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 11/03/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND Iodine enhancement is a marker for malignancy in pulmonary nodules. The purpose of this in vitro study was to assess whether dual energy computed tomography (DECT) can be used to detect iodine and to distinguish iodine from disperse calcifications in artificial pulmonary nodules. MATERIALS AND METHODS Small, medium, and large artificial nodules (n=54), with increasing concentrations of iodine or calcium corresponding to an increase in Hounsfield Units (HU) of 15, 30, 45, and 90 at 120 kV, were scanned in a chest phantom with DECT at 80 and 140 kV. Attenuation values of each nodule were measured using semi-automated volumetric analysis. The mean DE ratio with 95% confidence intervals (CI) was calculated for each nodule. RESULTS The mean maximum diameter of the 18 small nodules was 12 mm (standard deviation: 0.4), 16 mm (0.4) for the 18 medium nodules, and 30 mm (1.1) for the 18 large nodules. There was no overlap of 95% CI of DE ratios of iodine and calcium in nodules≥16 mm. In nodules<16 mm, there was an overlap of DE ratios in low contrast lesions. CONCLUSION DECT can distinguish iodine from calcium in artificial nodules≥16 mm in vitro. In smaller lesions, a clear differentiation is not possible.
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Affiliation(s)
- Naomi Knöss
- Department of Radiology, University Hospital Schleswig-Holstein, Campus Kiel, Germany.
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Dual energy CTA of the supraaortic arteries: Technical improvements with a novel dual source CT system. Eur J Radiol 2010; 76:e6-12. [DOI: 10.1016/j.ejrad.2009.09.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 09/14/2009] [Accepted: 09/18/2009] [Indexed: 11/21/2022]
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Thomas C, Korn A, Krauss B, Ketelsen D, Tsiflikas I, Reimann A, Brodoefel H, Claussen C, Kopp A, Ernemann U, Heuschmid M. Automatic bone and plaque removal using dual energy CT for head and neck angiography: Feasibility and initial performance evaluation. Eur J Radiol 2010; 76:61-7. [DOI: 10.1016/j.ejrad.2009.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 04/01/2009] [Accepted: 05/04/2009] [Indexed: 10/20/2022]
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Kumamaru KK, Hoppel BE, Mather RT, Rybicki FJ. CT angiography: current technology and clinical use. Radiol Clin North Am 2010; 48:213-35, vii. [PMID: 20609871 DOI: 10.1016/j.rcl.2010.02.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Since 1958, catheter angiography has assumed the role of gold standard for vascular imaging, despite the invasive nature of the procedure. Less invasive techniques for vascular imaging, such as computed tomographic angiography (CTA), have been developed and have matured in conjunction with developments in catheter arteriography. In a few cases, such as imaging, the aorta and the pulmonary arteries, CTA has supplanted catheter angiography as the gold standard. The expanding role of CTA emphasizes the need for deep, broad-based understanding of physical principles. This review describes CT hardware and associated software for angiography. The fundamentals of CTA physics are complemented with several clinical examples.
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Bae KT. Intravenous contrast medium administration and scan timing at CT: considerations and approaches. Radiology 2010; 256:32-61. [PMID: 20574084 DOI: 10.1148/radiol.10090908] [Citation(s) in RCA: 656] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The continuing advances in computed tomographic (CT) technology in the past decades have provided ongoing opportunities to improve CT image quality and clinical practice and discover new clinical CT imaging applications. New CT technology, however, has introduced new challenges in clinical radiology practice. One of the challenges is with intravenous contrast medium administration and scan timing. In this article, contrast medium pharmacokinetics and patient, contrast medium, and CT scanning factors associated with contrast enhancement and scan timing are presented and discussed. Published data from clinical studies of contrast medium and physiology are reviewed and interpreted. Computer simulation data are analyzed to provide an in-depth analysis of various factors associated with contrast enhancement and scan timing. On the basis of basic principles and analysis of the factors, clinical considerations and modifications to protocol design that are necessary to optimize contrast enhancement for common clinical CT applications are proposed.
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Affiliation(s)
- Kyongtae T Bae
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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