Martin Schneider

All Publications

• Superiorized Photo-Acoustic Non-NEgative Reconstruction (SPANNER) for Clinical Photoacoustic Imaging. IEEE transactions on medical imaging Steinberg, I. n., Kim, J. n., Schneider, M. K., Hyun, D. n., Zlitni, A. n., Hooper, S. M., Klap, T. n., Sonn, G. A., Dahl, J. J., Kim, C. n., Gambhir, S. S. 2021; PP

  Abstract

  Photoacoustic (PA) imaging can revolutionize medical ultrasound by augmenting it with molecular information. However, clinical translation of PA imaging remains a challenge due to the limited viewing angles and imaging depth. Described here is a new robust algorithm called Superiorized Photo-Acoustic Non-NEgative Reconstruction (SPANNER), designed to reconstruct PA images in real-time and to address the artifacts associated with limited viewing angles and imaging depth. The method utilizes precise forward modeling of the PA propagation and reception of signals while accounting for the effects of acoustic absorption, element size, shape, and sensitivity, as well as the transducer's impulse response and directivity pattern. A fast superiorized conjugate gradient algorithm is used for inversion. SPANNER is compared to three reconstruction algorithms: delay-and-sum (DAS), universal back-projection (UBP), and model-based reconstruction (MBR). All four algorithms are applied to both simulations and experimental data acquired from tissue-mimicking phantoms, ex vivo tissue samples, and in vivo imaging of the prostates in patients. Simulations and phantom experiments highlight the ability of SPANNER to improve contrast to background ratio by up to 20 dB compared to all other algorithms, as well as a 3-fold increase in axial resolution compared to DAS and UBP. Applying SPANNER on contrast-enhanced PA images acquired from prostate cancer patients yielded a statistically significant difference before and after contrast agent administration, while the other three image reconstruction methods did not, thus highlighting SPANNER's performance in differentiating intrinsic from extrinsic PA signals and its ability to quantify PA signals from the contrast agent more accurately.

  View details for DOI 10.1109/TMI.2021.3068181

  View details for PubMedID 33755561

• A Distinct Role of the Autonomic Nervous System in Modulating the Function of Lymphatic Vessels under Physiological and Tumor-Draining Conditions CELL REPORTS Bachmann, S. B., Gsponer, D., Montoya-Zegarra, J. A., Schneider, M., Scholkmann, F., Tacconi, C., Noerrelykke, S. F., Proulx, S. T., Detmar, M. 2019; 27 (11): 3305-+

  Abstract

  Lymphatic vessels (LVs) are important in the regulation of tissue fluid homeostasis and the pathogenesis of tumor progression. We investigated the innervation of LVs and the response to agonists and antagonists of the autonomic nervous system in vivo. While skin-draining collecting LVs express muscarinic, α1- and β2-adrenergic receptors on lymphatic endothelial cells and smooth muscle cells, intestinal lacteals express only β-adrenergic receptors and muscarinic receptors on their smooth muscle cells. Quantitative in vivo near-infrared imaging of the exposed flank-collecting LV revealed that muscarinic and α1-adrenergic agonists increased LV contractility, whereas activation of β2-adrenergic receptors inhibited contractility and initiated nitric oxide (NO)-dependent vasodilation. Tumor-draining LVs were expanded and showed a higher innervation density and contractility that was reduced by treatment with atropine, phentolamine, and, most potently, isoproterenol. These findings likely have clinical implications given the impact of lymphatic fluid drainage on intratumoral fluid pressure and thus drug delivery.

  View details for DOI 10.1016/j.celrep.2019.05.050

  View details for Web of Science ID 000470993200017

  View details for PubMedID 31189113

  View details for PubMedCentralID PMC6581737

• An in vivo wound healing model for the characterization of the angiogenic process and its modulation by pharmacological interventions. Scientific reports Schneider, M. K., Ioanas, H. I., Xandry, J., Rudin, M. 2019; 9 (1): 6004

  Abstract

  Angiogenesis during wound healing is essential for tissue repair and also affected during cancer treatment by anti-angiogenic drugs. Here, we introduce a minimally invasive wound healing model in the mouse ear to assess angiogenesis with high spatiotemporal resolution in a longitudinal manner in vivo using two-photon microscopy in mice expressing GCaMP2 in arterial endothelial cells. The development of vascular sprouts occurred in a highly orchestrated manner within a time window of 8 days following wounding. Novel sprouts developed exclusively from the distal stump of the transsected arteries, growing towards the proximal arterial stump. This was in line with the incidence of Ca2+ transients in the arterial endothelial cells, most probably a result of VEGF stimulation, which were more numerous on the distal part. Functional analysis revealed perfusion across the wound site via arterial sprouts developed between days 6 and 8 following the incision. At day 8, proximal and distal arteries were structurally and functionally connected, though only 2/3 of all sprouts detected were actually perfused. Treatment with the FDA approved drug, sunitinib, the preclinical drug AZD4547, as well as with the combination of the two agents had significant effects on both structural and functional readouts of neo-angiogenesis. The simplicity and high reproducibility of the model makes it an attractive tool for elucidating migratory activity, phenotype and functionality of endothelial cells during angiogenesis and for evaluating specific anti-angiogenic drug interventions.

  View details for DOI 10.1038/s41598-019-42479-1

  View details for PubMedID 30979919

  View details for PubMedCentralID PMC6461656

• EMMPRIN and its ligand Cyclophilin A as novel diagnostic markers in inflammatory cardiomyopathy INTERNATIONAL JOURNAL OF CARDIOLOGY Seizer, P., Geisler, T., Bigalke, B., Schneider, M., Klingel, K., Kandolf, R., Stellos, K., Schreieck, J., Gawaz, M., May, A. E. 2013; 163 (3): 299–304

  Abstract

  During inflammatory cardiomyopathy matrix metalloproteinases are crucially involved in cardiac remodeling. The aim of the present study was to investigate whether the "extracellular matrix metalloproteinase inducer" EMMPRIN (CD147) and its ligand Cyclophilin A (CyPA) are upregulated in inflammatory cardiomyopathy and may serve as diagnostic markers. Therefore, a series of 102 human endomyocardial biopsies were analyzed for the expression of EMMPRIN and CyPA and correlated with histological and immunohistological findings.Endomyocardial biopsies were stained for EMMPRIN and CyPA in addition to standard histology (HE, Trichrom) and immunohistological stainings (MHC-II, CD68, CD3). 39 (38.2%) biopsies met the immunohistological criteria of an inflammatory cardiomyopathy. EMMPRIN, which was predominantly expressed on cardiomyocytes, was slightly (but significantly) upregulated in non inflammatory cardiomyopathies compared to normal histopathological findings and highly upregulated in inflammatory cardiomyopathy compared to both non inflammatory cardiomyopathy and normal histopathology. In contrast, CyPA reveals no enhanced expression in non inflammatory cardiomyopathies and a highly enhanced expression in inflammatory cardiomyopathy, where it is closely associated with leucocytes infiltrates. We found a strong correlation between both EMMPRIN and CyPA with the expression of MHC-II molecules (correlation coefficient 0.475 and 0.527, p<0.05). Moreover, we found a correlation for both EMMPRIN and CyPA with CD68 (correlation coefficient 0.393 and 0.387, p<0.05) and CD3 (correlation coefficient 0.360 and 0.235, p<0.05).EMMPRIN is enhanced in both inflammatory and non inflammatory cardiomyopathies and can serve as a marker of myocardial remodeling. CyPA may represent a novel and specific marker for cardiac inflammation.

  View details for DOI 10.1016/j.ijcard.2011.06.049

  View details for Web of Science ID 000315156000019

  View details for PubMedID 21724278