Abstract:BACKGROUND AND PURPOSE: Dual-energy CT features the opportunity to differentiate among up to 3 different materials because the absorption of x-rays depends on the applied tube voltage and the atomic number of the material. For example, it is possible to distinguish between blood-brain barrier disruption and an intracerebral hemorrhage following treatment for a stroke. The aim of this study was to evaluate whether dual-energy CT is capable of distinguishing intra-arterial contrast agent from residually clotted … Show more
“…Recent medical literature advocates DECT for detecting residual peripheral intra-arterial thrombus after mechanical thrombectomy. 24 In the immediate postembolectomy setting, conventional residual thrombus on virtual non-contrast images shows a significantly higher attenuation relative to the perfused arteries but importantly not on the weighted average images (reconstructed conventional image) or iodine map. 23,25 Conversely, ISFT will be of low attenuation on virtual non-contrast images but will show higher attenuation on weighted average images and iodine map.…”
Aim Iodine-stained fragmented thromboembolism (ISFT) is a rare phenomenon encountered in the immediate aftermath of mechanical thrombectomy or rarely as a complication of post–carotid stenting. The aim was to describe the imaging appearance and discuss its pathophysiology. Method This is a retrospective review of patients who underwent mechanical thrombectomy for acute stroke at a single institution over the period of one year. All patients underwent the standard acute stroke imaging protocol (CT head, CT angiogram (CTA) and CT brain perfusion) and when clinically appropriate followed by catheter angiogram and mechanical thrombectomy. ISFT was defined as an arterial luminal filling defect with Hounsfield density equal to or greater than iodine seen on the biplanar CT or conventional CT. The presence and location of ISFT were documented. Standard CT angiogram (CTA) or magnetic resonance angiogram (MRA) was performed 24–48 hours after the neurointerventional procedure to assess for recanalization, volume of infarction and the fate of the ISFT. Results ISFTs were identified in eight (five males and three females, age range 18–80 years) out of 49 patients in the following locations: distal M1 ( n = 1), M2 ( n = 4), M3 ( n = 1), A1 ( n = 1), distal A2 ( n = 1). ISFT and vessel recanalization occurred in five patients on follow-up. ISFT and vessel occlusion persisted in two patients. Conclusion ISFT is likely the result of mechanical disruption of a thromboembolus, and porosity of the thromboembolus fragment may transiently retain iodinated contrast. Recognition of this entity may be important to aid detection of residual thromboembolism and avoid misinterpretation as calcified thromboembolism.
“…Recent medical literature advocates DECT for detecting residual peripheral intra-arterial thrombus after mechanical thrombectomy. 24 In the immediate postembolectomy setting, conventional residual thrombus on virtual non-contrast images shows a significantly higher attenuation relative to the perfused arteries but importantly not on the weighted average images (reconstructed conventional image) or iodine map. 23,25 Conversely, ISFT will be of low attenuation on virtual non-contrast images but will show higher attenuation on weighted average images and iodine map.…”
Aim Iodine-stained fragmented thromboembolism (ISFT) is a rare phenomenon encountered in the immediate aftermath of mechanical thrombectomy or rarely as a complication of post–carotid stenting. The aim was to describe the imaging appearance and discuss its pathophysiology. Method This is a retrospective review of patients who underwent mechanical thrombectomy for acute stroke at a single institution over the period of one year. All patients underwent the standard acute stroke imaging protocol (CT head, CT angiogram (CTA) and CT brain perfusion) and when clinically appropriate followed by catheter angiogram and mechanical thrombectomy. ISFT was defined as an arterial luminal filling defect with Hounsfield density equal to or greater than iodine seen on the biplanar CT or conventional CT. The presence and location of ISFT were documented. Standard CT angiogram (CTA) or magnetic resonance angiogram (MRA) was performed 24–48 hours after the neurointerventional procedure to assess for recanalization, volume of infarction and the fate of the ISFT. Results ISFTs were identified in eight (five males and three females, age range 18–80 years) out of 49 patients in the following locations: distal M1 ( n = 1), M2 ( n = 4), M3 ( n = 1), A1 ( n = 1), distal A2 ( n = 1). ISFT and vessel recanalization occurred in five patients on follow-up. ISFT and vessel occlusion persisted in two patients. Conclusion ISFT is likely the result of mechanical disruption of a thromboembolus, and porosity of the thromboembolus fragment may transiently retain iodinated contrast. Recognition of this entity may be important to aid detection of residual thromboembolism and avoid misinterpretation as calcified thromboembolism.
“…38 VNC images can also be used on post-EVT CT head to subtract residual contrast in the arteries and identify residual arterial thromboembolic material. 43 An in vitro study has demonstrated that VME techniques can differentiate red blood cell- and fibrin-rich clot that would have potential for predicting outcomes in thrombolysis or inform which device is best for clot retrieval in EVT. 44…”
Dual-energy computed tomography (CT) is a promising tool with increasing availability and multiple emerging and established clinical applications in neuroradiology. With its ability to allow characterization of materials based on their differential attenuation when imaged at two different energy levels, dual-energy CT can help identify the composition of brain, neck, and spinal components. Virtual monoenergetic imaging allows a range of simulated single energy-level reconstructions to be created with postprocessing. Low-energy reconstructions can aid identification of edema, ischemia, and subtle lesions due to increased soft tissue contrast as well as increasing contrast-to-noise ratios on angiographic imaging. Higher energy reconstructions can reduce image artifact from dental amalgam, aneurysm clips and coils, spinal hardware, dense contrast, and dense bones. Differentiating iodine from hemorrhage may help guide management of patients after thrombectomy and aid diagnosis of enhancing tumors within parenchymal hemorrhages. Iodine quantification may predict hematoma expansion in aneurysmal bleeds and outcomes in traumatic brain injury. Calcium and bone subtraction can be used to distinguish hemorrhage from brain parenchymal mineralization as well as improving visualization of extra-axial lesions and vessels adjacent to dense plaque or skull. This article reviews the basics of dual-energy CT and highlights many of its clinical applications in the evaluation of acute neurological presentations.
“…As with the VNC reconstructions from CT angiography, hyperdense arteries can be detected; however, no evaluation of the VNC with regard to the detection of early infarctions was performed, which is at least equally important in the acute stages [ 41 ]. In the second in vivo study, there was no comparison of arteries with residual clot material to the “gold-standard,” TICI scoring (thrombolysis in cerebral infarction), although conventional angiography studies were available [ 42 ]. The results about clot composition of artificial clots have yet to be verified in vivo [ 43 , 44 ].…”
Section: Clot Imagingmentioning
confidence: 99%
“…Arteries with clot material were significantly denser than perfused arteries on the VNC only (Fig. 4 ) [ 42 ]. Fig.…”
Dual-energy computed tomography (DECT) allows distinguishing between tissues with similar X-ray attenuation but different atomic numbers. Recent studies demonstrated that this technique has several areas of application in patients with ischemic stroke and a potential impact on patient management. After endovascular stroke therapy (EST), hyperdense areas can represent either hemorrhage or contrast staining due to blood-brain barrier disruption, which can be differentiated reliably by DECT. Further applications are improved visualization of early infarctions, compared to single-energy computed tomography, and prediction of transformation into infarction or hemorrhage in contrast-enhancing areas. In addition, DECT allows detection and evaluation of the material composition of intra-arterial clots after EST. This review summarizes the clinical state-of-the-art of DECT in patients with stroke, and features some prospects for future developments.
Key points
• Dual-energy computed tomography (DECT) allows differentiation between tissues with similar X-ray attenuation but differentatomic numbers.
• DECT has several areas of application in patients with ischemic stroke and a potential impact on patient management.
• Prospects for future developments in DECT may improve treatment decision-making.
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