Fig. 2.

MSOT imaging of healthy and affected muscles. To illustrate differences between healthy and affected muscles, exemplary image sections of the right biceps from a SMA patient and the respective HV are shown. From top to bottom: a schematic cartoon, reflected ultrasound computed tomography (RUCT) images, MSOT SWL 800 nm, MSOT parameters HbR, HbO2, collagen and lipid images are displayed. The cartoon shows the muscle within its margins. In HV homogenous muscle fibers are expected, whereas patchy clusters of hypertrophic and atrophic muscles fibers lead to the moth-eaten pattern in SMA patients. RUCT images show inhomogeneous muscle tissue, with increased echogenicity of the diseased muscle. Optoacoustic SWL 800 nm images reveal patchy signal patterns with alternating very high and very low signal intensities in SMA patients in contrast to a homogenous signal band in the healthy muscle. Merged images of different MSOT parameters (HbR, HbO2, collagen, lipid) suppose patchy clusters of increased fatty and fibrotic transformed tissue components. Scale bar indicates 1 cm. bv = blood vessel, subcut. fat = subcutaneous fat.