Evaluation of cervical lymph nodes using multispectral optoacoustic tomography: a proof-of-concept study.

OBJECTIVES: Examination of lymph nodes is one of the most common indications for imaging in the head and neck region. The purpose of this study is to evaluate whether multispectral optoacoustic tomography can be used to observe chromophore differences between benign and malignant neck lymph nodes. MATERIALS AND METHODS: Proof-of-concept ex vivo study of resected cervical lymph nodes from 11 patients. The examination of lymph nodes included imaging with hybrid ultrasound and multispectral tomography system followed by spectral unmixing to separate signals from the endogenous chromophores water, lipid, hemoglobin and oxygenated hemoglobin; calculation of semi-quantitative parameters (total hemoglobin and relative oxygenation of hemoglobin). Comparison of the results from the hybrid measurement with the histopathological results. RESULTS: Most patients suffered from squamous cell carcinoma (n = 7), also metastasis from salivary gland adenocarcinoma and papillary thyroid carcinoma, were included. The comparison between benign cervical lymph nodes and metastases showed significant differences for the absorbers water, lipid, hemoglobin and oxygenated hemoglobin and total hemoglobin. CONCLUSIONS: Our ex vivo study suggests that multispectral optoacoustic tomography can be used to detect differences between reactive lymph nodes and metastases. The measurement of endogenous chromophores can be used for this purpose. The examinations are non-invasively and thus potentially improve diagnostic prediction. However, potential influences from the ex vivo setting must be considered.

Reduction of oedema formation after preconditioning with dopamine in an isolated rat lung model is mediated by adrenergic receptors.

BACKGROUND: Donor treatment with dopamine (DA) is an effective modality to improve organ quality by reduction of hypothermic, ischemic and reperfusion (I/R) injury. It is unknown by which mechanism DA reduces oedema formation and inflammation. Therefore we tested the first time in an isolated rat lung model if dopaminergic or adrenergic receptors are involved. MATERIAL/METHODS: Rats were treated for 1 hr with NaCl, DA or simultaneously with DA alpha- beta- D1- or D2-receptor blockers. Thereafter lungs were explanted, flushed with Perfadex-solution and stored at 4°C. Peak inspiratory pressure (PIP), pulmonary arterial pressure (PAP) and lung weight were measured during reperfusion of 3 hrs. Inflammatory mediators and the expression of adhesion molecules were measured after perfusion. RESULTS: Up to 6 hours of hypothermia did not influence oedema formation or PIP and PAP during reperfusion time. However, hypothermia after 8 hrs significantly increased PIP, PAP and pulmonary oedema in NaCl, alpha- and beta-blocker treated lungs, but significantly not in DA, D1- or D2-blocker treated lungs. Perfusion and ventilation alone induced a strong upregulation of cytokine-induced neutrophil chemoattractant-1 and adhesion molecules in untreated, alpha- and beta-blocker treated lungs, while in DA, D1- and D2-blocker treated lungs significant lower levels were found. CONCLUSIONS: Our study suggests that dopamine mediated protective effects on I/R damage and inflammation in donor lungs are most likely mediated via adrenergic receptors. These findings are highly relevant because new strategies for organ preservation are necessary in terms of long donation waiting lists.