Document Detail


Evaluation of optimal scan duration and end time in cerebral CT perfusion study.
MedLine Citation:
PMID:  16342908     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: The purpose of this study was to evaluate the optimal end time of scanning and the influence of varying the number of source images adopted for calculation of the parameter values in computerized tomography (CT) perfusion. MATERIALS AND METHODS: Nineteen CT perfusion studies in 14 patients with cerebrovascular disease were retrospectively analyzed. CT perfusion scanning was performed using continuous scans of 1 sec/rotation x60 sec with 5-mm-thick sections. To determine the appropriate end time of scanning, the time-density curves (TDCs) of the anterior cerebral artery (ACA), superior sagittal sinus (SSS), and basal ganglia were analyzed. The functional maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) were retrospectively generated from various numbers (30, 35, 40, 45, 50, 55, and 60) of source images. Defining the values calculated from the number of source images equal to the end time of the first pass as standard values, the percentage difference between the standard values and the values generated from various numbers of sources were evaluated. RESULTS: The TDCs of SSS showed the latest end time of the first pass (mean, 38.6+/-5.2 sec; range, 32 to 48 sec). Therefore, the values calculated from the number of source images equal to the end time of the first pass of SSS were defined as standard values. Increase and decrease of the number of source images for calculation resulted in increase of the percentage difference in every parameter value. The percentage differences ranged up to 49.6% for CBF, 48.0% for CBV, and 20.0% for MTT. CONCLUSIONS: Scanning until the end time of the first pass of SSS is necessary and sufficient for reliable measurement. Variable scan time based on the TDC of the SSS may be of better utility than use of fixed scan time. Further, the radiation dose could be minimized in many cases by reducing the scan time.
Authors:
Masaaki Hirata; Yoshifumi Sugawara; Kenya Murase; Hitoshi Miki; Teruhito Mochizuki
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Publication Detail:
Type:  Evaluation Studies; Journal Article    
Journal Detail:
Title:  Radiation medicine     Volume:  23     ISSN:  0288-2043     ISO Abbreviation:  Radiat Med     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-12-13     Completed Date:  2006-02-16     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8412264     Medline TA:  Radiat Med     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  351-63     Citation Subset:  IM    
Affiliation:
Department of Radiology, Ehime University School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan.
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MeSH Terms
Descriptor/Qualifier:
Aged
Anterior Cerebral Artery / radiography
Basal Ganglia / blood supply,  radiography
Blood Flow Velocity / physiology
Blood Volume / physiology
Cerebrovascular Circulation / physiology*
Cerebrovascular Disorders / physiopathology,  radiography
Contrast Media / administration & dosage
Female
Humans
Image Processing, Computer-Assisted / methods
Male
Middle Aged
Radiographic Image Enhancement / methods
Retrospective Studies
Time Factors
Tomography, X-Ray Computed / methods*
Chemical
Reg. No./Substance:
0/Contrast Media

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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