Background. Hyperspectral imaging (HSI) is a relatively new method used in image-26 guided and precision surgery, which has shown promising results for characterization 27 of tissues and assessment of physiologic tissue parameters. Previous methods used 28 for analysis of preconditioning concepts in patients and animal models have shown 29 several limitations of application. The aim of this study was to evaluate HSI for the 30 measurement of ischemic conditioning effects during esophagectomy. 31 Methods. Intraoperative hyperspectral images of the gastric tube through the mini-32 thoracotomy were recorded from n=22 patients, 14 of whom underwent laparoscopic 33 gastrolysis and ischemic conditioning of the stomach with two-step transthoracic 34 esophagectomy and gastric pull-up with intrathoracic anastomosis after 3-7 days. 35 The tip of the gastric tube (later esophago-gastric anastomosis) was measured with 36 HSI. Analysis software provides a RGB image and 4 false color images representing 37 physiologic parameters of the recorded tissue area intraoperatively. These parameters contain tissue oxygenation (StO2), perfusion-(NIR Perfusion Index), 1 organ hemoglobin-(OHI) and tissue water index (TWI). 2 Results. Intraoperative HSI of the gastric conduit was possible in all patients and did 3 not prolong the regular operative procedure due to its quick applicability. In particular, 4 the tissue oxygenation of the gastric conduit was significantly higher in patients who 5 underwent ischemic conditioning (StO2Precond. = 78%; StO2NoPrecond. = 66%; p = 0.03). Conclusions. HSI is suitable for contact-free, non-invasive and intraoperative 7 evaluation of physiological tissue parameters within gastric conduits. Therefore HSI is 8 a valuable method for evaluating ischemic conditioning effects and may contribute to 9 reduce anastomotic complications. Additional studies are needed to establish normal 10 values and thresholds of the presented parameters for the gastric conduit 11 anastomotic site.

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Significance: Hyperspectral imaging (HSI) can support intraoperative perfusion assessment, the identification of tissue structures, and the detection of cancerous lesions. The practical use of HSI for minimal-invasive surgery is currently limited, for example, due to long acquisition times, missing video, or large setups. Aim: An HSI laparoscope is described and evaluated to address the requirements for clinical use and high-resolution spectral imaging. Approach: Reflectance measurements with reference objects and resected human tissue from 500 to 1000 nm are performed to show the consistency with an approved medical HSI device for open surgery. Varying object distances are investigated, and the signal-to-noise ratio (SNR) is determined for different light sources. Results: The handheld design enables real-time processing and visualization of HSI data during acquisition within 4.6 s. A color video is provided simultaneously and can be augmented with spectral information from push-broom imaging. The reflectance data from the HSI system for open surgery at 50 cm and the HSI laparoscope are consistent for object distances up to 10 cm. A standard rigid laparoscope in combination with a customized LED light source resulted in a mean SNR of 30 to 43 dB (500 to 950 nm). Conclusions: Compact and rapid HSI with a high spatial-and spectral-resolution is feasible in clinical practice. Our work may support future studies on minimally invasive HSI to reduce intraand postoperative complications.

The HSI method provides a non-contact, non-invasive, intraoperative imaging procedure without the use of a contrast medium, which enables a real-time analysis of physiological anastomotic parameters, which may contribute to determine the "ideal" anastomotic region. In light of this, the establishment of this methodology in the field of visceral surgery, enabling the generation of normal or cut off values for different gastrointestinal anastomotic types, is an obvious necessity.

Auf der Grundlage von IR‐Untersuchungen im Bereich von 200–2 400 cm−1, von Elektronenspektren und Röntgenuntersuchungen werden die Strukturen von 3d‐Metall‐dicyanamiden M(N(CN)2)2 (M = Mn, Fe, Co, Ni, Cu, Zn) beschrieben. Die Verbindungen lassen sich zwei verschiedenen Strukturtypen zuordnen, in denen die Anionen entweder als dreizählige oder zweizählige Brückenliganden auftreten. Kobalt‐ und Mangan‐dicyanamid bilden Struktur‐Isomere mit pseudo‐oktaedrischer (α‐Formen) bzw. ‐tetraedrischer Mikrosymmetrie (β‐Formen). Der polymertetraedrische Verbindungstyp, dem auch Zinkdicyanamid zuzuordnen ist, scheint eine bisher nicht beschriebene Bindungsart verbrückender Dicyanamid‐Gruppen zu enthalten.

Highlights Hyperspectral Imaging (HSI) is non-contact, non-ionizing and non-invasive. HSI detects tissue pathology based on spectral characteristics of different tissues. HSI is well suited for counter perfusion staining in anatomic liver resection. HSI can be used for future image guided liver surgery.

Objectives Free flap surgery is an essential procedure in soft tissue reconstruction. Complications due to vascular compromise often require revision surgery or flap removal. We present hyperspectral imaging (HSI) as a new tool in flap monitoring to improve sensitivity compared to established monitoring tools. Methods We performed a prospective observational cohort study including 22 patients. Flap perfusion was assessed by standard clinical parameters, Doppler ultrasound, and HSI on t0 (0 h), t1 (16–28 h postoperatively), and t2 (39–77 h postoperatively). HSI records light spectra from 500 to 1000 nm and provides information on tissue morphology, composition, and physiology. These parameters contain tissue oxygenation (StO2), near-infrared perfusion- (NIR PI), tissue hemoglobin- (THI), and tissue water index (TWI). Results Total flap loss was seen in n = 4 and partial loss in n = 2 cases. Every patient with StO2 or NIR PI below 40 at t1 had to be revised. No single patient with StO2 or NIR PI above 40 at t1 had to be revised. Significant differences between feasable (StO2 = 49; NIR PI = 45; THI = 16; TWI = 56) and flaps with revision surgery [StO2 = 28 (p < 0.001); NIR PI = 26 (p = 0.002); THI = 56 (p = 0.002); TWI = 47 (p = 0.045)] were present in all HSI parameters at t1 and even more significant at t2 (p < 0.0001). Conclusion HSI provides valuable data in free flap monitoring. The technique seems to be superior to the gold standard of flap monitoring. StO2 and NIR PI deliver the most valuable data and 40 could be used as a future threshold in surgical decision making. Clinical Trial Register This study is registered at the German Clinical Trials Register (DRKS) under the registration number DRKS00020926.

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