AJR
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Raggi, P.
Right arrow Articles by Cooil, B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Raggi, P.
Right arrow Articles by Cooil, B.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
Hotlight (NEW!)
Right arrow
What's Hotlight?

Calcium Scoring of the Coronary Artery by Electron Beam CT

How to Apply an Individual Attenuation Threshold

Paolo Raggi1, Tracy Q. Callister2 and Bruce Cooil3

1 Tulane University School of Medicine, Cardiology Section, SL48, 1430 Tulane Ave., New Orleans, LA 70112.
2 EBT Research Foundation, 353 New Shackle Island Rd., Hendersonville, TN 37025.
3 Owen Graduate School of Management, Vanderbilt University, 401 21st Ave. S. Nashville, TN 37203.



View larger version (135K):

[in a new window]
  		Fig. 1A. —Axial electron beam CT scans of chest obtained in 74-year-old woman at level of proximal to middle portion of left anterior descending coronary artery show calcification. Computer software automatically highlights all pixels, with CT number > 130 H in yellow. Along with calcification of left anterior descending coronary artery (in white rectangle), substantial image noise (scattered yellow pixels) is also seen.

 


View larger version (125K):

[in a new window]
  		Fig. 1B. —Axial electron beam CT scans of chest obtained in 74-year-old woman at level of proximal to middle portion of left anterior descending coronary artery show calcification. Computer software automatically highlights all pixels, with CT number > 130 H in yellow. After calculation of optimal attenuation threshold by adding 3 standard deviations (SD) to measured mean soft-tissue CT number, background noise disappears. In this example, mean soft-tissue CT number is 45 H with SD of 40 H, and calculated optimal threshold is 165 H.

 


View larger version (13K):

[in a new window]
  		Fig. 2. —Box plots of mean soft-tissue attenuation measured at level of origin of left main coronary artery (high-level mean) and at level of diaphragm (low-level mean).

 


View larger version (12K):

[in a new window]
  		Fig. 3. —Box plots of standard deviation (SD) of soft-tissue attenuation measured at level of origin of left main coronary artery (high-level SD) and at level of diaphragm (low-level SD).

 


View larger version (11K):

[in a new window]
  		Fig. 4. —Correlation between soft-tissue attenuation measurements made at bottom of heart (low level) and body weight in all 48 patients. As body weight increases, mean soft-tissue attenuation decreases and standard deviation increases.

 


View larger version (12K):

[in a new window]
  		Fig. 5. —Correlation between ideal threshold (mean soft-tissue CT number plus 3 standard deviations [SD]) at bottom of heart (low level) and patient's body weight. As body weight increases, ideal soft-tissue attenuation increases as function of increasing SD (y = 0.4839x + 26.179).

 

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?



HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2002 by the American Roentgen Ray Society.