ORIGINAL ARTICLES  VASCULAR PAPERS 

The Journal of Cardiovascular Surgery 1998 October;39(5):527-34

Copyright © 2000 EDIZIONI MINERVA MEDICA

language: English

Noninvasive characterization of plaque morphology using helical computed tomography

Estes J. M.*, Quist W. C.°°, Lo Gerfo F. W.**, Costello P.*

From the Department of Surgery, New England Medical Center, Tuffs University School of Medicine and the **Departments of Surgery, °°Pathology, and °Radiology New England Deaconess Hospital/Harvard Medical School, Boston, MA, USA

Back­ground. Evi­dence sug­gests ­that ath­e­ros­cle­rotic ­plaque com­po­si­tion and mor­phology are ­more impor­tant pre­dic­tors of ­plaque ­stability and clin­ical ­behavior ­than the ­degree of ­vessel sten­osis. Unfor­tu­nately, non­in­va­sive ­methods of ­plaque char­ac­ter­iza­tion in ­situ ­using ­duplex ultra­sound ­have ­been ­largely unsuc­cessful. We inves­ti­gated the accu­racy of hel­ical com­puted tomog­raphy (HCT) in ­defining ­plaque mor­phology in ­patients under­going ­carotid endar­te­rec­tomy.
­Methods. Can­di­dates for endar­te­rec­tomy ­were ­enrolled pros­pec­tively and under­went HCT ­with intra­ve­nous con­trast injec­tion. The atten­u­a­tion ­values (in Houns­field ­Units) of ­plaque fea­tures ­such as cal­cium, ­fibrous ­tissue, and ­lipid ­were meas­ured and cor­re­lated ­with the ­tissue ­types ­seen on micro­scopic exam­ina­tion. Per­cent ­luminal sten­osis ­derived ­from trans­verse HCT ­images was ­also com­pared to ­values ­obtained ­from ­duplex ultra­sound.
Set­ting. Ambu­la­tory ­patients ­referred to a ter­tiary, met­ro­pol­itan med­ical ­center.
­Results. A ­total of 21 out of 22 ­cases ­were suit­able for com­par­ison. Qual­ita­tively, HCT accu­rately ­defined ­plaque fea­tures con­taining cal­cium, ­fibrous ­stroma, and ­lipid. ­Using ­tissue atten­u­a­tion ­values (Houns­field ­Units - H), HCT dis­tin­guished ­between ­lipid and ­fibrous ­stroma (means 39±12 H and 90±24 H, respec­tively, p<0.001). HCT-­derived cal­cu­la­tions of per­cent sten­osis ­also cor­re­lated ­with the ultra­sound ­data (p<0.001).
Con­clu­sions. HCT is an accu­rate, non­in­va­sive ­means for stud­ying ­detailed ­plaque mor­phology and com­po­si­tion. ­This tech­nique pro­vides the ­basis for fur­ther ­studies cor­re­lating ­plaque ­anatomy ­with clin­ical ­behavior.