Virtual histology

As a luminogram, coronary angiography provides a good overview of
the coronary artery tree. Using quantitative coronary measurements,
the degree of coronary obstruction can be determined. The
limitation of coronary angiography is that it does not provide
information on the arterial wall structure and therefore cannot
assess the extent of atherosclerosis. Knowledge about adaptive
coronary remodelling processes as compensatory enlargement of the
coronary artery has focused diagnostic interest on the non-stenotic
lesions of the coronary tree. Intravascular ultrasound (IVUS) can
reveal discrepancies between the extent of coronary atherosclerosis
and angiography imaging by in vivo plaque imaging. Spectrum
analysis of IVUS-derived radiofrequency (RF) data enables a more
detailed analysis of plaque composition and morphology. Preliminary
in vitro studies correlated four histological plaque components
with a specific spectrum analysis of the RF data. The different
components (fibrous, fibrofatty, necrotic core and dense calcium)
are colour coded. Coronary tissue maps were reconstructed from RF
data using IVUS–Virtual Histology (VH IVUS) software (Real-Time VH,
Volcano Corporation, Rancho Cordova, California, USA). VH IVUS has
the potential to detect high-risk lesions and can provide new
insights into the pathophysiology of coronary artery disease. VH
IVUS allows the differentiation of different lesion types based on
information derived from histopathology. The in vivo specific
histological analysis of coronary atherosclerosis may allow better
stratification of treatment of patients with coronary artery
disease.