Table 1

Description of Nomenclature for Plaque Architecture on Invasive Coronary Imaging

TermDescription
IVUS-VH
 Pathological intimal thickening
  • A precursor of fibroatheroma, characterized by non-necrotic lipid pools within a structured matrix

  • ≥600 μm thickness for >20% of the circumference, with fibrofatty plaque >15% and no confluent NC or DC

 Fibrotic plaque
  • Dominant fibrous tissue and no confluent NC or DC

 Early fibroatheroma
  • Early NC with cholesterol clefts and cellular debris with a structured matrix

 Late fibroatheromas
  • Late NC with complete degradation of extracellular matrix

  • >10% confluent NC on 3 consecutive frames

 Thin-cap fibroatheroma
  • Late NC covered by thin fibrous caps <65 μm in thickness

  • >10% confluent NC on 3 consecutive frames and arc of NC in contact with the lumen for 360° along lumen circumference

 Fibrocalcific plaque
  • >10% confluent DC with no confluent NC

Grayscale IVUS
 Echo-attenuated plaque
  • Absence of the ultrasound signal behind plaque, hypoechoic or isoechoic with reference to the adventitia

 Echolucent plaque
  • Plaque containing a zone of absent or low echogenicity (with reference to adventitia) surrounded by tissue of greater echodensity

 Calcification
  • Brighter than reference adventitia resulting in acoustic shadowing

  • Spotty calcification comprises of small calcium deposits within arcs of <90° centered on the lumen

  • Superficial calcium is closer to the lumen, whereas deep calcium is situated closer to the adventitia

DC = dense calcium; IVUS-VH = intravascular ultrasound-virtual histology; NC = necrotic core.