Postoperative Befunde an der Wirbelsäule

Zusammenfassung: Die postoperative Bildgebung wird klassischerweise herangezogen zur Dokumentation der korrekten Implantatlage oder um Komplikationen auszuschließen, wenn der Patient postoperativ weiterhin Beschwerden angibt. In Abhängigkeit von der Fragestellung können verschiedene Modalitäten verwendet werden - alle mit Vor- und Nachteilen. Die konventionelle Röntgenuntersuchung wird zur Dokumentation der Implantatlage, Beurteilung der Stabilität oder im Follow-up zur Frage der Instabilität oder einer Implantatfraktur verwendet, wogegen Weichteilveränderungen nicht komplett beurteilt werden können. Neben diesen Indikationen wird eine Bildgebung bei persistierenden Beschwerden (meist Schmerzen) des Patienten veranlasst. Residuelles oder rezidiviertes Bandscheibengewebe, ein Hämatom oder eine Entzündung können am besten mit der MRT beurteilt werden. Die MRT sollte unmittelbar postoperativ durchgeführt werden, um eine physiologische Granulation im Zugangsgebiet von entzündlichen Veränderungen unterscheiden zu können. Oft kann die Bildgebung allein dies nicht unterscheiden, daher ist die Bildgebung nur ein weiteres Puzzelstück. Die Computertomographie ist die Modalität der Wahl zur Beurteilung von Knochen und eine Ergänzung bei neuen Verfahren wie der bildgestützten Kypho- oder Vertebroplasti

Entzündliche Erkrankungen der Wirbelsäule und des Myelons

Zusammenfassung: Entzündliche Erkrankungen der Wirbelsäule und des Myelons haben vielfältige Ursachen. Mit Ausnahme der degenerativ bedingten entzündlichen Veränderungen der Wirbelsäule selbst sind bakteriell, viral oder autoimmun vermittelte Entzündungen eher selten. Letztere sind klinisch und bildgebend auch schwer zu evaluieren, können aber wichtige Ursachen für Schmerzen und funktionelle Störungen sein. Dies gilt besonders, wenn sie unbehandelt bleiben. Bei schweren Krankheitsverläufen wie der Spondylodiszitis oder der rheumatoiden Arthritis kann es zu ernsten neurologischen Ausfällen kommen, v.a. bei fortschreitender intraspinaler Beteiligung. Entzündungen des Myelons selbst können durch konventionelle Röntgenuntersuchungen nicht und mit der Computertomographie nur selten festgestellt werden. Hier ist die Magnetresonanztomographie das bildgebende Verfahren der ersten Wahl, um Veränderungen des Myelons frühzeitig und differenziert zu beurteile

Impact of Software Modeling on the Accuracy of Perfusion MRI in Glioma

PURPOSE: To determine whether differences in modeling implementation will impact the correction of leakage effects (from blood brain barrier disruption) and relative cerebral blood volume (rCBV) calculations as measured on T2*-weighted dynamic susceptibility-weighted contrast-enhanced (DSC)-MRI at 3T field strength. MATERIALS AND METHODS: This HIPAA-compliant study included 52 glioma patients undergoing DSC-MRI. Thirty-six patients underwent both non Preload Dose (PLD) and PLD-corrected DSC acquisitions, with sixteen patients undergoing PLD-corrected acquisitions only. For each acquisition, we generated two sets of rCBV metrics using two separate, widely published, FDA-approved commercial software packages: IB Neuro (IBN) and NordicICE (NICE). We calculated 4 rCBV metrics within tumor volumes: mean rCBV, mode rCBV, percentage of voxels with rCBV > 1.75 (%>1.75), and percentage of voxels with rCBV > 1.0 (Fractional Tumor Burden or FTB). We determined Pearson (r) and Spearman (ρ) correlations between non-PLD- and PLD-corrected metrics. In a subset of recurrent glioblastoma patients (n=25), we determined Receiver Operator Characteristic (ROC) Areas-Under-Curve (AUC) for FTB accuracy to predict the tissue diagnosis of tumor recurrence versus post-treatment effect (PTRE). We also determined correlations between rCBV and microvessel area (MVA) from stereotactic biopsies (n=29) in twelve patients. RESULTS: Using IBN, rCBV metrics correlated highly between non-PLD- and PLD-corrected conditions for FTB (r=0.96, ρ=0.94), %>1.75 (r=0.93, ρ=0.91), mean (r=0.87, ρ=0.86) and mode (r=0.78, ρ=0.76). These correlations dropped substantially with NICE. Using FTB, IBN was more accurate than NICE in diagnosing tumor vs PTRE (AUC=0.85 vs 0.67) (p<0.01). The highest rCBV-MVA correlations required PLD and IBN (r=0.64, ρ=0.58, p=0.001). CONCLUSIONS: Different implementations of perfusion MRI software modeling can impact the accuracy of leakage correction, rCBV calculation, and correlations with histologic benchmarks

State-of-the-art of 3D cultures (organs-on-a-chip) in safety testing and pathophysiology.

Integrated approaches using different in vitro methods in combination with bioinformatics can (i) increase the success rate and speed of drug development; (ii) improve the accuracy of toxicological risk assessment; and (iii) increase our understanding of disease. Three-dimensional (3D) cell culture models are important building blocks of this strategy which has emerged during the last years. The majority of these models are organotypic, i.e., they aim to reproduce major functions of an organ or organ system. This implies in many cases that more than one cell type forms the 3D structure, and often matrix elements play an important role. This review summarizes the state of the art concerning commonalities of the different models. For instance, the theory of mass transport/metabolite exchange in 3D systems and the special analytical requirements for test endpoints in organotypic cultures are discussed in detail. In the next part, 3D model systems for selected organs--liver, lung, skin, brain--are presented and characterized in dedicated chapters. Also, 3D approaches to the modeling of tumors are presented and discussed. All chapters give a historical background, illustrate the large variety of approaches, and highlight up- and downsides as well as specific requirements. Moreover, they refer to the application in disease modeling, drug discovery and safety assessment. Finally, consensus recommendations indicate a roadmap for the successful implementation of 3D models in routine screening. It is expected that the use of such models will accelerate progress by reducing error rates and wrong predictions from compound testing

Integrating microtissues in nanofiber scaffolds for regenerative nanomedicine

A new generation of biomaterials focus on smart materials incorporating cells. Here, we describe a novel generation of synthetic nanofibrous implant functionalized with living microtissues for regenerative nanomedicine. The strategy designed here enhances the effectiveness of therapeutic implants compared to current approaches used in the clinic today based on single cells added to the implant

A 3D-microtissue-based phenotypic screening of radiation resistant tumor cells with synchronized chemotherapeutic treatment.

BACKGROUND: Radiation resistance presents a challenge to the effective treatment of cancer. If therapeutic compounds were capable of resensitizing resistant tumours then a concurrent chemo-radiation treatment could be used to overcome radiation resistance. METHODS: We have developed a phenotypic assay to investigate the response of radiation resistant breast cancer cells grown in 3D-microtissue spheroids to combinations of radiation and established chemotherapeutic drugs. The effects were quantified by real time high content imaging of GFP detection area over 14&nbsp;days. Ten established chemotherapeutic drugs were tested for their ability to enhance the effects of radiation. RESULTS: Of ten analysed chemotherapeutics, vinblastine was the most effective compound, with docetaxel and doxorubicine being less effective in combination with radiation. To investigate the response in a model closer to the in vivo situation we investigated the response of heterotypic 3D microtissues containing both fibroblasts and breast cancer cells. Drug treatment of these heterotypic 3D cultures confirmed treatment with radiation plus vinblastine to be additive in causing breast cancer growth inhibition. We have validated the screen by comparing radiation sensitizing effects of known chemotherapeutic agents. In both monotypic and heterotypic models the concurrent treatment of vinblastine and radiation proved more effective inhibitors of mammary cancer cell growth. The effective concentration range of both vinblastine and radiation are within the range used in treatment, suggesting the 3D model will offer a highly relevant screen for novel compounds. CONCLUSIONS: For the first time comfortable 3D cell-based phenotypic assay is available, that allows high throughput screening of compounds with radiation therapy modulating capacity, opening the field to drug discovery

[Postoperative findings in the spinal column]

Postoperative imaging after spinal surgery is usually performed to document the correct positioning of implants or to rule out complications if patients still suffer from pain after surgery. Depending on the question various imaging modalities can be used all of which have benefits and limitations. Conventional X-ray is used for the documentation of the correct positioning of spinal implants, stability (olisthesis) and during follow-up to rule out fractures or instability of the implants, whereas soft tissue changes cannot be completely assessed. Besides these indications, imaging is usually performed because of ongoing symptoms (pain for the most part) of the patients. Soft tissue changes including persistent or recurrent herniated disc tissue, hematoma or infection can best be depicted using magnetic resonance imaging (MRI) which should be performed within the immediate postoperative period to be able to distinguish physiological development of scar tissue from inflammatory changes in the area of the surgical approach. Often imaging alone cannot differentiate between these and imaging can therefore only be considered as an adjunct. Computed tomography is the modality of choice for the evaluation of bony structures and an adjunct of new therapies such as image-guided application of cement for kyphoplasty or vertebroplasty