Multispectral optoacoustic tomography of peripheral arterial disease based on muscle hemoglobin gradients-a pilot clinical study.

BACKGROUND

Current imaging assessment of peripheral artery disease (PAD) relies on anatomical cross-sectional visualizations of the affected arteries. Multispectral optoacoustic tomography (MSOT) is a novel molecular imaging technique that provides direct and label-free visualizations of soft tissue perfusion and oxygenation.

METHODS

MSOT was prospectively assessed in a pilot trial in healthy volunteers (group n=4, mean age 31, 50% male and group n=4, mean age 37.3, 75% male) and patients with intermittent claudication (group n=4, mean age 72, 75% male, PAD stage IIb). We conducted cuff-induced ischemia (group n) and resting state measurements (groups n and n) over the calf region. Spatially resolved mapping of oxygenated (HbO), deoxygenated (Hb) and total (THb) hemoglobin, as well as oxygen saturation (SO), were measured via hand-held hybrid MSOT-Ultrasound based purely on hemoglobin contrast.

RESULTS

Calf measurements in healthy volunteers revealed distinct dynamics for HbO, Hb, THb and SO under cuff-induced ischemia. HbO, THb and SO levels were significantly impaired in PAD patients compared to healthy volunteers (P<0.05 for all parameters). Revascularization led to significant improvements in HbO of the affected limb.

CONCLUSIONS

Clinical MSOT allows for non-invasive, label-free and real-time imaging of muscle oxygenation in health and disease with implications for diagnostics and therapy assessment in PAD.