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Shinohara Y, Ohmura T, Sasaki F, Sato Y, Inomata T, Itoh T, Kinoshita T. Dual-Energy Computed Tomography Virtual Noncalcium Imaging of Intracranial Arteries in Acute Ischemic Stroke: Differentiation Between Acute Thrombus and Calcification. J Comput Assist Tomogr 2024:00004728-990000000-00315. [PMID: 38657159 DOI: 10.1097/rct.0000000000001623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
OBJECTIVE Hyperdense artery sign (HAS) on noncontrast brain computed tomography (CT) indicates an acute thrombus within the cerebral artery. It is a valuable imaging biomarker for diagnosing large-vessel occlusion; however, its identification may be challenging with the presence of vascular calcification. Dual-energy CT virtual noncalcium (VNCa) imaging using a 3-material decomposition algorithm is helpful for differentiating between calcification and hemorrhage. This study aimed to clarify the potential of VNCa imaging for differentiating HAS from vascular calcification. METHODS Patients with acute ischemic stroke and large-vessel occlusion identified on MR angiography, who also underwent noncontrast dual-energy CT, were included. The 80 kV/Sn 140 kV mixed images, with a weighting factor of 0.4, were considered 120 kVp-equivalent images. Postprocessing using a 3-material decomposition algorithm to differentiate between calcium (Ca), cerebrospinal fluid, and hemorrhage was performed via a commercially available 3-dimensional workstation. A mixed image, VNCa image, color-coded Ca image, and color-coded Ca image with VNCa image overlay (color-coded Ca-overlay image) were obtained, and axial reconstruction with a 1-mm slice thickness was performed for each image type. Two experienced neuroradiologists conducted imaging evaluations in consensus. RESULTS Thirty-four patients (mean age, 76.0 years; 21 male and 13 female patients) were included. The mixed and VNCa images revealed an HAS (indicating an acute clot) corresponding to the large-vessel occlusion site in 30 patients. Among them, the VNCa and color-coded Ca-overlay images enabled clear differentiation between the acute thrombus and adjacent vessel wall calcification in 5 patients. Among the other 4 patients, the VNCa, Ca-overlay, and Ca images identified calcified cerebral emboli in the M1 segment in 1 patient. For the other 3 patients, no high attenuation corresponding to magnetic resonance angiography findings was observed in any of the mixed, VNCa, Ca-overlay, or Ca images. CONCLUSIONS VNCa and color-coded Ca-overlay images obtained via dual-energy brain CT enabled differentiation of acute thrombus from vessel wall calcification and calcified cerebral emboli in patients with acute ischemic stroke.
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Affiliation(s)
- Yuki Shinohara
- From the Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels-Akita, Akita, Japan
| | - Tomomi Ohmura
- From the Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels-Akita, Akita, Japan
| | - Fumiaki Sasaki
- From the Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels-Akita, Akita, Japan
| | - Yuichiro Sato
- From the Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels-Akita, Akita, Japan
| | - Takato Inomata
- From the Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels-Akita, Akita, Japan
| | - Toshihide Itoh
- CT Research and Collaboration Department, Diagnostic Imaging Division, Siemens Healthcare K.K., Tokyo, Japan
| | - Toshibumi Kinoshita
- From the Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels-Akita, Akita, Japan
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Oguro S, Mugikura S, Ota H, Bito S, Asami Y, Sotome W, Ito Y, Kaneko H, Suzuki K, Higuchi N, Takase K. Usefulness of maximum intensity projection images of non-enhanced CT for detection of hyperdense middle cerebral artery sign in acute thromboembolic ischemic stroke. Jpn J Radiol 2022; 40:1046-1052. [PMID: 35612726 PMCID: PMC9529686 DOI: 10.1007/s11604-022-01289-8] [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: 12/02/2021] [Accepted: 04/20/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE To compare the sensitivity of the hyperdense middle cerebral artery (MCA) sign between maximum intensity projection (MIP) and conventional averaged images in patients with acute focal neurological deficits with acute thromboembolic MCA occlusion (MCA occlusion group) and patients with acute focal neurological deficits without MCA occlusion (control group). MATERIALS AND METHODS Initial computed tomography (CT) scans on admission were reconstructed with 5 mm thickness at every 3 mm interval for averaged and MIP images from 1 mm thickness non-contrast axial source images. Images were obtained from 30 cases each in the MCA occlusion and control groups. The CT values in the region of interests (ROIs) on the affected and unaffected sides of the MCA were compared. To compare CT values among subjects, the CT values were normalized by obtaining a ratio on the affected and unaffected sides, and the normalized CT values were analyzed using the receiver operating characteristic (ROC) curve. RESULTS The hyperdense MCA sign was visually detected on MIP images in 90% cases and on 5 mm averaged images in only 57% cases in the MCA occlusion group. Based on the ROC analysis of the normalized ratio on the affected and unaffected sides, area under the curve of MIP image and averaged image was 0.941 and 0.655, respectively. On MIP images, the optimal threshold of the ratio on the affected and unaffected sides was 1.152 (sensitivity: 90.0%, and specificity: 93.3%). CONCLUSION The hyperdense MCA sign sensitivity on 5 mm MIP images was significantly higher than that on conventional 5 mm averaged CT images. This could be useful for the early initiation of proper therapy for patients with acute focal neurological deficits.
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Affiliation(s)
- Sota Oguro
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan.
| | - Shunji Mugikura
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan
| | - Hideki Ota
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan
| | - Seiji Bito
- Department of Internal Medicine, Tokyo Medical Center, Tokyo, Japan
| | - Yuta Asami
- Department of Diagnostic Radiology, Tokyo Medical Center, Tokyo, Japan
| | - Wataru Sotome
- Department of Diagnostic Radiology, Tokyo Medical Center, Tokyo, Japan
| | - Yoshiaki Ito
- Department of Diagnostic Radiology, Tokyo Medical Center, Tokyo, Japan
| | - Hideki Kaneko
- Department of Diagnostic Radiology, Tokyo Medical Center, Tokyo, Japan
| | - Kazuyo Suzuki
- Department of Diagnostic Radiology, Tokyo Medical Center, Tokyo, Japan
| | - Nobuya Higuchi
- Department of Diagnostic Radiology, Tokyo Medical Center, Tokyo, Japan
| | - Kei Takase
- Department of Diagnostic Radiology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan
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Abd Elkhalek YI, Elia RZ. Qualitative and quantitative value of hyperdense MCA sign as a prognostic marker for infarction. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2016. [DOI: 10.1016/j.ejrnm.2016.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Takhtani D, Dundamadappa S, Almast J. Role of noncontrast head CT in the assessment of vascular abnormalities in the emergency room. Emerg Radiol 2013; 20:529-41. [PMID: 23739799 DOI: 10.1007/s10140-013-1136-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 05/27/2013] [Indexed: 11/28/2022]
Abstract
Noncontrast CT of the head is a widely used noninvasive investigation for a variety of acute and chronic neurological conditions. Since CT head without contrast is usually the first and often the only investigation in the emergency room for many neurological symptoms, it is imperative to detect subtle vascular changes, which in many patients can be life-saving. The vascular abnormalities may present with increased density and/or size of the vessels, filling defects, and be associated with parenchymal and bony changes. In this article, we present examples of several vascular pathologies which can be identified on the noncontrast CT of the head, and learn imaging and interpretation techniques to help recognize what often are nebulous changes. While some of the findings are diagnostic by themselves and others subtle, any suspicious abnormality should be followed with dedicated vascular imaging such as CT/MR angiogram, venogram, or catheter angiogram for confirmation and better characterization.
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Affiliation(s)
- Deepak Takhtani
- University of Massachusetts Medical School, UMass Memorial Hospital, Worcester, MA, 01655, USA,
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Zuckerman SL, Mocco J. Use of thin-slice computed tomography in acute ischemic stroke. World Neurosurg 2012; 79:213-6. [PMID: 23266456 DOI: 10.1016/j.wneu.2012.12.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Abstract
Radiologists face the daily challenge of analyzing and interpreting a high volume of images in a timely manner. Minimizing errors, whether perceptual or cognitive in nature, is paramount for high-quality diagnostics and patient care. There are certain areas within the head encountered at routine brain imaging in which the interpreting radiologist is most prone to make perceptual errors. These areas, or "blind spots," include the cerebral sulci, dural sinuses, orbits, cavernous sinuses, clivus, Meckel cave, brainstem, skull base, and parapharyngeal soft tissues. In addition, the use of an inappropriate window width and level for the evaluation of computed tomographic (CT) scans can be a virtual, rather than an anatomic, blind spot. The inclusion of a comprehensive checklist for evaluation of these blind spots as part of every brain imaging study is crucial for avoiding false-negative results. Knowledge of the anatomic features of these blind spots is also crucial, as well as familiarity with the normal CT and magnetic resonance imaging findings in these areas. In addition, the radiologist should be aware of possible interpretation pitfalls that may lead to false-positive results (eg, normal anatomic variants that may be mistaken for pathologic conditions). Finally, a well-developed differential diagnosis will help ensure correct interpretation and appropriate patient treatment.
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Affiliation(s)
- Simin Bahrami
- Department of Radiological Sciences, Ronald Reagan UCLA Medical Center, 1st Floor, Los Angeles, CA 90095-7437, USA.
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Przelaskowski A, Sklinda K, Bargieł P, Walecki J, Biesiadko-Matuszewska M, Kazubek M. Improved early stroke detection: Wavelet-based perception enhancement of computerized tomography exams. Comput Biol Med 2007; 37:524-33. [PMID: 16999952 DOI: 10.1016/j.compbiomed.2006.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nonenhanced computerized tomography (CT) exams were used to detect acute stroke by notification of hypodense area. Infarction perception improvement by data denoising and local contrast enhancement in multi-scale domain was proposed. The wavelet-based image processing method enhanced the subtlest signs of hypodensity, which were often invisible in standard CT scan review. Thus improved detection efficiency of perceptual ischemic changes was investigated. Data processing became more effective by initial segmentation of brain tissue and extraction of regions susceptible to tissue density changes. The new method was experimentally verified. Sensitivity of stroke diagnosis increased to 56.3% in comparison to 12.5% of standard CT scan preview.
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Affiliation(s)
- A Przelaskowski
- Institute of Radioelectronics, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warszawa, Poland.
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Abstract
The hyperdense artery sign on noncontrast head CT is thought to be one of the earliest and most useful signs of intra-arterial clot and probable (clinical) stroke. It should be evaluated in the context of the clinical scenario. Rigorous criteria should be applied in order to reduce potential false positives. The hyperdense middle cerebral artery sign is the most studied version and correlates with patient outcome. Our data suggest that the density on noncontrast head CT is not likely to universally represent in situ clot.
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Affiliation(s)
- Mark E Mullins
- Division of Neuroradiology, Massachusetts General Hospital, Boston 02114, USA.
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Bae KT, Mody GN, Balfe DM, Bhalla S, Gierada DS, Gutierrez FR, Menias CO, Woodard PK, Goo JM, Hildebolt CF. CT Depiction of Pulmonary Emboli: Display Window Settings. Radiology 2005; 236:677-84. [PMID: 15972332 DOI: 10.1148/radiol.2362041558] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To compare computed tomographic (CT) window settings selected by radiologists with those determined by using two alternative approaches for depiction of pulmonary emboli (PE). MATERIALS AND METHODS Institutional review board approval was obtained; informed consent was not required. This study was compliant with the Health Insurance Portability and Accountability Act. Twenty-five clinical chest CT studies were obtained with a standardized PE protocol and retrospectively evaluated by five chest and two body CT radiologists. Of these studies, 13 were positive for PE, and 12 were negative. At the main pulmonary artery (PA), mean attenuations (MPA) and standard deviations (SDPA) were measured. Initially, images were displayed with a standard mediastinal window setting (window width, W = 400 HU; window center, C = 30 HU), and each observer adjusted the setting to a personally preferred setting (eg, "personal") for PE detection. Images displayed at this setting were compared in a side-by-side fashion with the "modified" (W = MPA + 2 . SDPA, C = W/2) and "double-half" (W = 2 . MPA, C = MPA/2) window setting. Each observer rated images from 1 (ie, most preferred) to 3 (ie, least preferred). For quantitative analysis, window width and center value of each setting were divided by corresponding MPA to compute a width ratio and a center ratio. Window settings and ratings were compared with repeated-measures analysis of variance, paired t tests, and Wilcoxon signed-rank tests. RESULTS Ratings for all three types of window settings were significantly different (P < .001). Observers preferred their personal settings the most and the modified settings the least. Mean ratios for the seven observers were 1.68 +/- 0.20 for window width and 0.47 +/- 0.08 for window center. Window width ratios for all settings were significantly different from each other (P < .001). Window center ratios were significantly higher for the modified setting than for the double-half setting (P = .013). Values for mean PA attenuation were correlated with window width ratios for six (86%) observers (mean r2 value = 0.29 +/- 0.19, P < or = .03) and with window center ratios for four (57%) observers (mean r2 value = 0.16 +/- 0.14, P < or = .02), thus indicating a trend of setting window width and window center higher when contrast enhancement is lower and vice versa. CONCLUSION On average, observers selected CT window settings for PE detection at a window width of slightly less than twice the mean PA attenuation and at a window center of about half the mean PA attenuation. Observers tended to use larger window widths and centers as the degree of PA enhancement was lower.
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Affiliation(s)
- Kyongtae T Bae
- 1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63110, USA.
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Gadda D, Vannucchi L, Niccolai F, Neri AT, Carmignani L, Pacini P. Multidetector computed tomography of the head in acute stroke: predictive value of different patterns of the dense artery sign revealed by maximum intensity projection reformations for location and extent of the infarcted area. Eur Radiol 2005; 15:2387-95. [PMID: 16059679 DOI: 10.1007/s00330-005-2850-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2004] [Revised: 06/12/2005] [Accepted: 06/21/2005] [Indexed: 11/25/2022]
Abstract
Maximum intensity projections reconstructions from 2.5 mm unenhanced multidetector computed tomography axial slices were obtained from 49 patients within the first 6 h of anterior-circulation cerebral strokes to identify different patterns of the dense artery sign and their prognostic implications for location and extent of the infarcted areas. The dense artery sign was found in 67.3% of cases. Increased density of the whole M1 segment with extension to M2 of the middle cerebral artery was associated with a wider extension of cerebral infarcts in comparison to M1 segment alone or distal M1 and M2. A dense sylvian branch of the middle cerebral artery pattern was associated with a more restricted extension of infarct territory. We found 62.5% of patients without a demonstrable dense artery to have a limited peripheral cortical or capsulonuclear lesion. In patients with a 7-10 points on the Alberta Stroke Early Programme Computed Tomography Score and a dense proximal MCA in the first hours of ictus the mean decrease in the score between baseline and follow-up was 5.09+/-1.92 points. In conclusion, maximum intensity projections from thin-slice images can be quickly obtained from standard computed tomography datasets using a multidetector scanner and are useful in identifying and correctly localizing the dense artery sign, with prognostic implications for the entity of cerebral damage.
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Affiliation(s)
- Davide Gadda
- U.O. Radiodiagnostica, Ospedale del Ceppo, Piazza San Lorenzo, 51100, Pistoia, Italy.
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Gadda D. A case of bilateral dense middle cerebral arteries with CT angiographic confirmation of vascular occlusion. Emerg Radiol 2003; 10:142-3. [PMID: 15290502 DOI: 10.1007/s10140-003-0299-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2003] [Accepted: 07/03/2003] [Indexed: 11/30/2022]
Abstract
Hyperattenuating middle cerebral arteries on CT in acute stroke should generally not be associated with presence of intraluminal clot when bilaterally seen. We report a case of a woman who underwent emergency CT 60 min after sudden onset of coma. Bilateral dense middle cerebral arteries without parenchymal hypoattenuating areas or indirect signs of cerebral edema were present. CT angiography confirmed occlusion of the right middle cerebral artery and left internal carotid artery and middle cerebral artery.
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Affiliation(s)
- Davide Gadda
- Department of Radiology, Pistoia General Hospital, Pistoia, Italy.
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