TY - JOUR T1 - <strong>Multispect</strong><strong>ral Optoacoustic Tomography: A Novel Label-Free Imaging Technique for the Assessment of </strong><strong>hyperthyroid diseases</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 525 LP - 525 VL - 60 IS - supplement 1 AU - Markus Kroenke AU - Angelos Karlas AU - Nikolina Fasoula AU - Niklas Markwardt AU - Klemens Scheidhauer AU - Matthias Eiber AU - Wolfgang Weber AU - Vasilis Ntziachristos Y1 - 2019/05/01 UR - http://jnm.snmjournals.org/content/60/supplement_1/525.abstract N2 - 525Introduction: Optoacoustic imaging is a novel technique with strong translational potential, which is based on the homonymous phenomenon to provide dynamic morphological and molecular tissue visualizations by tracking natural light absorbers. Tissue is illuminated by fast laser pulses and ultrasound waves are generated upon light absorption. The presence of hemoglobin and other intrinsic light absorbers, such as lipids, renders optoacoustics as an ideal technique for molecular imaging without the need for extra contrast agents. Herein, we investigate the use of multispectral optoacoustic tomography (MSOT) in hyperthyroid diseases in vivo. Methods: In this ongoing prospective study, we have so far enrolled 8 healthy volunteers and 19 patients (17 women, 2 men, median age: 53.5 years, range: 20-78). Nine patients suffered from Graves’ disease and ten from autonomous adenoma. All patients received axial MSOT Imaging of the neck (including thyroid, M. sternocleidomastoideus and carotid artery), ultrasound (b-mode and Doppler-mode) and scintigraphy of the thyroid. The levels of oxy- and deoxy-hemoglobin, the local oxygen saturation (sO2) as well as the lipid and water content of the thyroid gland were extracted by means of spectral unmixing from the corresponding MSOT readouts. For data analysis, different techniques were applied (backprojection and model-based reconstruction, deconvolution with electrical and spatial impulse response, use of ultrasound priors, linear unmixing and spectral tissue characterization). Results: So far, model-based reconstruction without deconvolution seems to offer highest imaging accuracy and contrast. The use of ultrasound priors might help improve image quality by noise reduction. The normal thyroid gland demonstrated significantly higher sO2 than skeletal muscle (58% vs 46% uncorrected) while lipid content was low and similar in both tissues. Patients with Graves’ disease had normal fT3 and fT4 values, while patients with autonomous adenoma had a suppressed TSH. Graves’ disease was confirmed by antibody titers. MSOT was capable of detecting the autonomous adenoma and Graves’ disease by showing in both increased perfusion (as confirmed by Doppler-ultrasonography), increased deoxyHb, 0.55 au and 0.79 au compared to 0.49 au, p&lt;0.05, increased oxyHb, 0.86 au, 1.2 au compared 0.77 au p&lt;0.05, and decreased levels of sO2, 0.56 and 0.54 compared to 0.58, p&lt;0.05. There were no significant differences in fat and water content found. Discussion: In contrast to the intensity-based signal of traditional ultrasonography MSOT of the thyroid can provide a variety of functional parameters including oxygenation, lipid and water content in one imaging session. Since MSOT is non-invasive and does not require ionizing radiation, this new technology shows significant potential for studies of thyroid pathophysiology in various diseases. ER -