Author + information
- Ayeeshik Kole1,
- Yingchun Cao2,
- Jie Hui2,
- Islam Bolad1,
- Mouhamad Alloosh1,
- Ji-Xin Cheng3 and
- Michael Sturek1
Current imaging tools lack sensitivity and depth resolution to accurately quantify lipid core content at different stages of disease. Here, we present an intravascular catheter which can produce co-registered images of morphology and depth-resolved lipid core content via ultrasound and photoacoustic modes, respectively.
We performed in vivo intravascular photoacoustic-ultrasound (IVPA-US) imaging of the iliac arteries of Ossabaw swine with dyslipidemia (n=3) and lean control swine (n=3) to investigate sensitivity to detect early atherosclerosis. We repeated imaging ex vivo with near-infrared spectroscopy (NIRS) for comparison to IVPA-US and histology. To investigate late-stage atherosclerosis, we performed ex vivo IVPA-US imaging of a fresh human coronary artery, and compared to NIRS and histology.
Along the artery lengths, dyslipidemic swine showed significantly greater average cross-sectional lipid area than lean swine (0.089 mm2 vs 0.059 mm2; p<0.0001). Similar results were shown in ex vivo NIRS measurements, in which dyslipidemic swine had a greater average total lipid core burden index (LCBI) than lean swine (50.3 vs 12.0; p=0.48). The small average lipid areas and LCBIs agreed with histopathology, which showed mild neointimal thickening in both groups.
On ex vivo imaging of the human coronary artery and histology, we identified advanced fibroatheromas with calcification (Figure). The lesion had a total lipid area, as measured in a 4 mm segment, of 25.95 mm2 and lipid core volume of 0.247 mm3. The NIRS chemogram-derived lipid area was comparable at 26.38 mm2 with a maximum LCBI of 326 in the 4 mm segment.
As confirmed by NIRS and histology, IVPA-US has sensitivity and depth resolution to detect lipid content in early disease, which enables quantification and localization of lipid cores within plaques.