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An S, Hwang G, Kim R, Cha J, Lee HC, Hwang T. Optimizing contrast protocol for bone-subtraction CT angiography of intracranial arteries in normal dogs using 160-slice CT. Vet Med Sci 2023; 9:2504-2512. [PMID: 37766491 PMCID: PMC10650334 DOI: 10.1002/vms3.1252] [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: 04/18/2023] [Revised: 07/09/2023] [Accepted: 08/18/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND Bone-subtraction computed tomography angiography (CTA) (BSCTA) is a new technique designed to overcome the limitation of three-dimensional CTA, where the vessels surrounded by bone and calcification can be obscured. An optimal contrast CT protocol for intracranial artery visualization with BSCTA has yet to be established in dogs. OBJECTIVES The purpose of this study was to determine the optimal contrast protocol of CTA for visualizing intracranial artery using an automatic bone-subtraction technique in dogs. METHODS Brain CTA was performed four times for each of nine healthy beagle dogs to cover all the contrast protocols: two different contrast iodine concentrations (300 and 370 mgI/mL) and two different contrast media injection rates (2 and 4 mL/s). Bone removal post-processing was performed automatically by subtracting the non-enhanced CT data from the contrast CT data using a dedicated workstation. The bone-subtracted intracranial vessels were analysed for quantitative and qualitative evaluation. RESULTS Quantitative evaluation showed significantly higher CT attenuation values for the group with a 370 mgI/mL iodine content at a rate of 4 mL/s than the two groups with a 300 mgI/mL iodine content at the rates of 2 and 4 mL/s (p < 0.001). Qualitative assessment revealed significantly higher mean scores for the 370 mgI/mL groups than the 300 mgI/mL groups and significantly higher mean scores for the 4 mL/s groups than the 2 mL/s groups (p < 0.05). CONCLUSIONS The optimal contrast protocol for BSCTA suggests that high iodine material concentration and high injection rate should be used for strong arterial attenuation and great visualization of the intracranial arterial structure in dogs.
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Affiliation(s)
- Soyon An
- Institute of Animal MedicineCollege of Veterinary MedicineGyeongsang National UniversityJinjuRepublic of Korea
| | - Gunha Hwang
- Institute of Animal MedicineCollege of Veterinary MedicineGyeongsang National UniversityJinjuRepublic of Korea
| | - Rakhoon Kim
- Institute of Animal MedicineCollege of Veterinary MedicineGyeongsang National UniversityJinjuRepublic of Korea
| | - Jihye Cha
- Animal Genome & BioinformaticsNational Institute of Animal Science, RDAWanjuRepublic of Korea
| | - Hee Chun Lee
- Institute of Animal MedicineCollege of Veterinary MedicineGyeongsang National UniversityJinjuRepublic of Korea
| | - Tae‐Sung Hwang
- Institute of Animal MedicineCollege of Veterinary MedicineGyeongsang National UniversityJinjuRepublic of Korea
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Dieckmeyer M, Sollmann N, Kupfer K, Löffler MT, Paprottka KJ, Kirschke JS, Baum T. Computed Tomography of the Head : A Systematic Review on Acquisition and Reconstruction Techniques to Reduce Radiation Dose. Clin Neuroradiol 2023; 33:591-610. [PMID: 36862232 PMCID: PMC10449676 DOI: 10.1007/s00062-023-01271-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/24/2023] [Indexed: 03/03/2023]
Abstract
In 1971, the first computed tomography (CT) scan was performed on a patient's brain. Clinical CT systems were introduced in 1974 and dedicated to head imaging only. New technological developments, broader availability, and the clinical success of CT led to a steady growth in examination numbers. Most frequent indications for non-contrast CT (NCCT) of the head include the assessment of ischemia and stroke, intracranial hemorrhage and trauma, while CT angiography (CTA) has become the standard for first-line cerebrovascular evaluation; however, resulting improvements in patient management and clinical outcomes come at the cost of radiation exposure, increasing the risk for secondary morbidity. Therefore, radiation dose optimization should always be part of technical advancements in CT imaging but how can the dose be optimized? What dose reduction can be achieved without compromising diagnostic value, and what is the potential of the upcoming technologies artificial intelligence and photon counting CT? In this article, we look for answers to these questions by reviewing dose reduction techniques with respect to the major clinical indications of NCCT and CTA of the head, including a brief perspective on what to expect from current and future developments in CT technology with respect to radiation dose optimization.
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Affiliation(s)
- Michael Dieckmeyer
- Department of Diagnostic, Interventional and Pediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Nico Sollmann
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Ulm, Ulm, Germany
| | - Karina Kupfer
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maximilian T. Löffler
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Freiburg im Breisgau, Germany
| | - Karolin J. Paprottka
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jan S. Kirschke
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Thomas Baum
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
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Saraf R, Sharma R, Jaini LV, Mhashal S. External carotid artery pseudoaneurysm with arteriovenous fistula: A rare complication of glass shrapnel injury. Indian J Radiol Imaging 2021; 26:510-512. [PMID: 28104948 PMCID: PMC5201084 DOI: 10.4103/0971-3026.195780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Posttraumatic external carotid artery pseudoaneurysm with arteriovenous fistula is a rare condition. An 8-year-old child presented with painful pulsatile swelling in the preauricular region following a penetrating glass shrapnel injury. Detailed evaluation showed distal external carotid artery pseudoaneurysm with fistula, which was draining into the retromandibular vein. Endovascular treatment was performed. This case highlights the role of endovascular intervention for such rare complicated vascular pathologies.
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Affiliation(s)
- Rashmi Saraf
- Department of Radiology, Seth G.S. Medical College and K.E.M. Hospital, Mumbai, Maharashtra, India
| | - Rajaram Sharma
- Department of Radiology, Seth G.S. Medical College and K.E.M. Hospital, Mumbai, Maharashtra, India
| | - Lodha V Jaini
- Department of E.N.T and Head and Neck Surgery, Seth G.S. Medical College and K.E.M. Hospital, Mumbai, Maharashtra, India
| | - Shashikant Mhashal
- Department of E.N.T and Head and Neck Surgery, Seth G.S. Medical College and K.E.M. Hospital, Mumbai, Maharashtra, India
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Harvey EC, Feng M, Ji X, Zhang R, Li Y, Chen GH, Li K. Impacts of photon counting CT to maximum intensity projection (MIP) images of cerebral CT angiography: theoretical and experimental studies. Phys Med Biol 2019; 64:185015. [PMID: 31315093 DOI: 10.1088/1361-6560/ab32fe] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
While CTA is an established clinical gold standard for imaging large cerebral arteries and veins, an important challenge that currently remains for CTA is its limited performance in imaging small perforating arteries with diameters below 0.5 mm. The purpose of this work was to theoretically and experimentally study the potential benefits of using photon counting detector (PCD)-based CT (PCCT) to improve the performance of CTA in imaging these small arteries. In particular, the study focused on an important component of the CTA image package known as the maximum intensity projection (MIP) image. To help understand how the physical properties of a detector quantitatively influence the MIP image quality, a theoretical model on the statistical properties of MIP images was developed. After validating this model, it was used to explore the individual and joint contribution of the following detector properties to the MIP signal-to-noise ratio (SNR): inter-slice noise covariance, spatial resolution along the z direction, and native pixel pitch along z. The model demonstrated that superior slice sensitivity, reduced inter-slice noise correlation, and smaller native pixel pitch along z provided by PCDs lead to improved vessel SNR in MIP images. Finally, experiments were performed by scanning an anthropomorphic cerebral angiographic phantom using a benchtop PCCT system and a commercial MDCT system. The experimental MIP results consistently demonstrated that compared with MDCT, PCCT provides superior vessel conspicuity and reduced artifactual stenosis.
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Affiliation(s)
- Evan Cary Harvey
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, United States of America
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Abstract
When evaluating a patient with an oculomotor cranial nerve palsy it may be unclear which neuroimaging modality is optimal; MRI, MR angiography, computed tomography, computed tomography angiography, or intraarterial digital subtraction angiography. We discuss the clinical guidelines in the evaluation of such patients and review neuroimaging techniques, outlining the advantages and disadvantages of each.
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Affiliation(s)
- Michael S Vaphiades
- Department of Ophthalmology, University of Alabama at Birmingham, Suite 601, 700 South 18th Street, Birmingham, AL 35233, USA; Department of Neurology, University of Alabama at Birmingham, 1720 2nd Avenue S, Birmingham, AL 35233, USA; Department of Neurosurgery, University of Alabama at Birmingham, 1720 2nd Avenue S, Birmingham, AL 35233, USA.
| | - Glenn H Roberson
- Department of Radiology, University of Alabama at Birmingham, JT N420, 619 19th Street South, Birmingham, AL 35249-6830, USA
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Ni QQ, Chen GZ, Schoepf UJ, Klitsie MAJ, De Cecco CN, Zhou CS, Luo S, Lu GM, Zhang LJ. Cerebral CTA with Low Tube Voltage and Low Contrast Material Volume for Detection of Intracranial Aneurysms. AJNR Am J Neuroradiol 2016; 37:1774-1780. [PMID: 27151751 DOI: 10.3174/ajnr.a4803] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/06/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Multidetector row CTA has become the primary imaging technique for detecting intracranial aneurysms. Technical progress enables the use of cerebral CTA with lower radiation doses and contrast media. We evaluated the diagnostic accuracy of 80-kV(peak) cerebral CTA with 30 mL of contrast agent for detecting intracranial aneurysms. MATERIALS AND METHODS Two hundred four patients were randomly divided into 2 groups. Patients in group A (n = 102) underwent 80-kVp CTA with 30 mL of contrast agent, while patients in group B (n = 102) underwent conventional CTA (120 kVp, 60 mL of contrast agent). All patients underwent DSA. Image quality, diagnostic accuracy, and radiation dose between the 2 groups were compared. RESULTS Diagnostic image quality was obtained in 100 and 99 patients in groups A and B, respectively (P = .65). With DSA as reference standard, diagnostic accuracy on a per-aneurysm basis was 89.9% for group A and 93.9% for group B. For evaluating smaller aneurysms (<3 mm), the diagnostic accuracy of groups A and B was 86.3% and 90.8%, respectively. There was no difference in diagnostic accuracy between each CTA group and DSA (all, P > .05) or between the 2 CTA groups (all, P > .05). The effective dose in group A was reduced by 72.7% compared with group B. CONCLUSIONS In detecting intracranial aneurysms with substantial radiation dose and contrast agent reduction, 80-kVp/30-mL contrast CTA provides the same diagnostic accuracy as conventional CTA.
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Affiliation(s)
- Q Q Ni
- From the Department of Medical Imaging (Q.Q.N., G.Z.C., C.S.Z., S.L., G.M.L., L.J.Z.), Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - G Z Chen
- From the Department of Medical Imaging (Q.Q.N., G.Z.C., C.S.Z., S.L., G.M.L., L.J.Z.), Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - U J Schoepf
- Department of Radiology and Radiological Science (U.J.S., M.A.J.K., C.N.D.C.), Medical University of South Carolina, Charleston, South Carolina
| | - M A J Klitsie
- Department of Radiology and Radiological Science (U.J.S., M.A.J.K., C.N.D.C.), Medical University of South Carolina, Charleston, South Carolina
| | - C N De Cecco
- Department of Radiology and Radiological Science (U.J.S., M.A.J.K., C.N.D.C.), Medical University of South Carolina, Charleston, South Carolina
| | - C S Zhou
- From the Department of Medical Imaging (Q.Q.N., G.Z.C., C.S.Z., S.L., G.M.L., L.J.Z.), Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - S Luo
- From the Department of Medical Imaging (Q.Q.N., G.Z.C., C.S.Z., S.L., G.M.L., L.J.Z.), Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - G M Lu
- From the Department of Medical Imaging (Q.Q.N., G.Z.C., C.S.Z., S.L., G.M.L., L.J.Z.), Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - L J Zhang
- From the Department of Medical Imaging (Q.Q.N., G.Z.C., C.S.Z., S.L., G.M.L., L.J.Z.), Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
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Improved CT Detection of Acute Herpes Simplex Virus Type 1 Encephalitis Based on a Frequency-Selective Nonlinear Blending: Comparison With MRI. AJR Am J Roentgenol 2016; 207:1082-1088. [PMID: 27533625 DOI: 10.2214/ajr.16.16032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study is to compare the diagnostic efficacy of a new CT postprocessing tool based on frequency-selective nonlinear blending (best-contrast CT) with that of standard linear blending of unenhanced head CT in patients with herpes simplex virus type 1 and herpes simplex virus encephalitis (HSE), using FLAIR MRI sequences as the standard of reference. MATERIALS AND METHODS Fifteen consecutive patients (six women and nine men; mean [± SD] age, 60 ± 19 years) with proven HSE (positive polymerase chain reaction results from CSF analysis and the presence of neurologic deficits) were retrospectively enrolled. All patients had undergone head CT and MRI (mean time interval, 2 ± 2 days). After standardized unenhanced head CT scans were read, presets of the best-contrast algorithm were determined (center, 30 HU; delta, 5 HU; slope, 5 nondimensional), and resulting images were analyzed. Contrast enhancement was objectively measured by ROI analysis, comparing contrast-to-noise ratios (CNRs) of unenhanced CT and best-contrast CT. FLAIR and DWI MRI sequences were analyzed, and FLAIR was considered as the standard of reference. For assessment of disease extent, a previously reported 50-point score (HSE score) was used. RESULTS CNR values for unenhanced head CT (CNR, 5.42 ± 2.77) could be statistically significantly increased using best-contrast CT (CNR, 9.62 ± 4.28) (p = 0.003). FLAIR sequences yielded a median HSE score of 9.0 (range, 6-17) and DWI sequences yielded HSE scores of 6.0 (range, 5-17). By comparison, unenhanced head CT resulted in a median HSE score of 3.5 (range, 1-6). The median best-contrast CT HSE score was 7.5 (range, 6-10). Agreement between FLAIR and unenhanced CT was 54.44%, that between DWI and best-contrast CT was 95.36%, and that between FLAIR and best-contrast CT was 85.21%. The most frequently overseen findings were located at the level of the upper part of the mesencephalon and at the subthalamic or insular level. CONCLUSION Frequency-selective nonlinear blending significantly increases contrast and detects brain parenchymal involvement in HSE more sensitively compared with unenhanced CT. The sensitivity of best-contrast CT seems to be equal to that of DWI and almost as good as that of FLAIR.
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Biswas S, Chandran A, Radon M, Puthuran M, Bhojak M, Nahser HC, Das K. Accuracy of four-dimensional CT angiography in detection and characterisation of arteriovenous malformations and dural arteriovenous fistulas. Neuroradiol J 2015; 28:376-84. [PMID: 26427892 DOI: 10.1177/1971400915604526] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A retrospective review was made to assess the accuracy of four dimensional CT angiogram (4D-CTA) in diagnosis of arteriovenous malformations (AVM) and dural arteriovenous fistulas (DAVF), with catheter-based digital-subtraction angiogram (DSA) being gold standard. 33 pairs of investigations (DSA and 4D-CTA) were performed primarily for suspicion of AVM/DAVF. Based on blinded reports, sensitivity and specificity for detection of AVM/DAVF were 77% (95% CI: 46-95%) and 100% (95% CI: 83-100%) respectively. Positive predictive value was 100% (95% CI: 69-100%) and negative predictive value 87% (95% CI: 66-97%). 4D-CTA is a practical minimally-invasive technique for evaluating cerebrovascular pathologies. There is good agreement between the findings of 4D-CTA and DSA despite the differences in temporal and spatial resolutions. 4D-CTA may obviate the need for DSA in a subgroup of patients who would otherwise have undergone this invasive investigation, which carries a risk of important complications.
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Affiliation(s)
- Shubhabrata Biswas
- Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, UK
| | - Arun Chandran
- Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, UK
| | - Mark Radon
- Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, UK
| | - Mani Puthuran
- Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, UK
| | - Maneesh Bhojak
- Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, UK
| | | | - Kumar Das
- Department of Neuroradiology, The Walton Centre for Neurology and Neurosurgery, UK
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