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Featured researches published by Patrick Eppenberger.


European Journal of Radiology | 2012

MR neurography of the median nerve at 3.0 T: Optimization of diffusion tensor imaging and fiber tractography

Roman Guggenberger; Patrick Eppenberger; Daniel Markovic; Daniel Nanz; Avneesh Chhabra; Klaas P. Pruessmann; Gustav Andreisek

OBJECTIVES The purpose of this study was to systematically assess the optimal b-value and reconstruction parameters for DTI and fiber tractography of the median nerve at 3.0T. METHODS Local ethical board approved study with 45 healthy volunteers (15 men, 30 women; mean age, 41 ± 3.4 years) who underwent DTI of the right wrist at 3.0T. A single-shot echo-planar-imaging sequence (TR/TE 10123/40 ms) was acquired at four different b-values (800, 1000, 1200, and 1400 s/mm(2)). Two independent readers performed post processing and fiber-tractography. Fractional anisotropy (FA) maps were calculated. Fiber tracts of the median nerve were generated using four different algorithms containing different FA thresholds and different angulation tolerances. Data were evaluated quantitatively and qualitatively. RESULTS Tracking algorithms using a minimum FA threshold of 0.2 and a maximum angulation of 10° were significantly better than other algorithms. Fiber tractography generated significantly longer fibers in DTI acquisitions with higher b-values (1200 and 1400 s/mm(2) versus 800 s/mm(2); p<0.001). The overall quality of fiber tractography was best at a b-value of 1200 s/mm(2) (p<0.001). CONCLUSIONS In conclusion, our results indicate use of b-values between 1000 and 1400 s/mm(2) for DTI of the median nerve at 3.0T. Optimal reconstruction parameters for fiber tractography should encompass a minimum FA threshold of 0.2 and a maximum angulation tolerance of 10.


Neuroimaging Clinics of North America | 2014

Magnetic resonance neurography: diffusion tensor imaging and future directions.

Patrick Eppenberger; Gustav Andreisek; Avneesh Chhabra

Magnetic resonance (MR) neurography has progressed in the past 2 decades because of rapid technological developments in both hardware and software. In addition to improvements in high-resolution anatomic pulse sequences, functional techniques are becoming feasible. This article presents the current state-of-the-art three-dimensional anatomic techniques, discusses the advantages of functional techniques being exploited, and portrays novel contrast types and molecular techniques that are under development and promise a bright future for this rapidly evolving technique.


Evolution, medicine, and public health | 2018

Increasing variability of body mass and health correlates in Swiss conscripts, a possible role of relaxed natural selection?

Kaspar Staub; Maciej Henneberg; Francesco M. Galassi; Patrick Eppenberger; Martin Haeusler; Irina Morozova; Frank J. Rühli; Nicole Bender

The distribution of height, weight, and body mass index of Swiss conscripts widened over the last 140 years. There are now more underweight and overweight conscripts who show similar increases in inflam-matory and metabolic fault blood parameters. Both facts indicate a possible role of relaxed natural selection on genes affecting metabolism and body composition.


Pathobiology | 2018

Egyptian Canopics Jars at the Crossroad of Medicine and Archaeology: Overview of 100 Years of Research and Future Scientific Expectations

Sidney Senti; Michael E. Habicht; Enrique Rayo; Patrick Eppenberger; Frank J. Rühli; Francesco M. Galassi

Ancient Egyptian human remains have been of interest in the fields of both medical and Egyptological research for decades. However, canopic jar holders for internal organs (liver, lungs, stomach, intestines) of Egyptian mummies appear to be but a very occasional source of data for such investigations. The few medical approaches focusing on the content of these jars are summarized and listed according to pathogens and diseases to give a structured overview of this field of study. An extensive search of the literature has been conducted from different bibliographic databases with a total of n = 26 studies found. The majority of diseases found consisted of infectious diseases and internal medicine conditions such as schistosomiasis or emphysema. These are just 2 examples of many that, instead of primarily affecting bone, muscle or skin, specifically target internal organs. Hence, a better understanding of the evolution of diseases that still affect mankind could be gained. In conclusion, this reassessment shows that canopic jars represent a highly underestimated source for histological, radiological and ancient DNA examination of Ancient Egyptian remains and should, thus, be more and more brought back into the focus of retrospective medical research.


Imaging Science in Dentistry | 2018

Application of portable digital radiography for dental investigations of ancient Egyptian mummies during archaeological excavations: Evaluation and discussion of the advantages and limitations of different approaches and projections

Roger Seiler; Patrick Eppenberger; Frank J. Rühli

Purpose In the age of X-ray computed tomography (CT) and digital volume tomography (DVT), with their outstanding post-processing capabilities, indications for planar radiography for the study of the dentition of ancient Egyptian mummies may easily be overlooked. In this article, the advantages and limitations of different approaches and projections are discussed for planar oral and maxillofacial radiography using portable digital X-ray equipment during archaeological excavations. Furthermore, recommendations are provided regarding projections and sample positioning in this context. Materials and Methods A total of 55 specimens, including 19 skeletonized mandibles, 14 skeletonized skulls, 18 separate mummified heads, and 4 partially preserved mummies were imaged using portable digital X-ray equipment in the course of archaeological excavations led by the University of Basel in the Valley of the Kings between 2009 and 2012. Images were evaluated by 2 authors with regard to the visibility of diagnostically relevant dental structures using a 4-point grading system (Likert scale). Results Overall, the visibility of diagnostically relevant dental structures was rated highest by both authors on X-ray images acquired using a dental detector. The tube-shift technique in the lateral projections of mandibular dentition achieved the second-best rating, and lateral projections achieved the third-best rating. Conclusion Conventional planar digital X-ray imaging, due to its ubiquity, remains an excellent method–and often the only practicable one–for examining the skulls and teeth of ancient Egyptian mummies under field conditions. Radiographic images of excellent diagnostic quality can be obtained, if an appropriate methodology regarding the selected projections and sample placement is followed.


British Journal of Clinical Pharmacology | 2017

A brief pictorial and historical introduction to guaiacum – from a putative cure for syphilis to an actual screening method for colorectal cancer

Patrick Eppenberger; Francesco M. Galassi; Frank J. Rühli

Having re-emerged on a global scale during the last few decades, with an estimated incidence in adults of 10.6 million cases in 2008 [2], syphilis (Lues venerea), a bacterial infection caused by Treponema pallidum, was first mentioned in European medical writings in the 1490s, as a consequence of the return of Columbus’s crew to Europe in 1492 and the later epidemic during the French invasion of Naples in 1495. While the presence of the disease in the Old World prior to Columbus’s voyages has long been at the heart of a heated palaeopathological debate [3], reconstructing the historical presentations and evolutionary history of the disease and its treatment can be achieved both via analysis of ancient human remains as well as consultation of literary and artistic sources [4, 5]. With respect to the latter, we would like to highlight an engraving by Philip Galle (1537–1612), reproducing the artist Jan van der Straet’s (1523–1605) painting, dating back to the late 16th century, of a scene depicting a wealthy man receiving treatment for syphilis by means of Guaiacum officinale (Figure 1). From a pharmacological perspective, this denotes the immense reputation that this plant acquired as a putative cure for syphilis in the course of the 16th century. It was the first drug administered to treat syphilis in Europe, after being first imported in 1508 from the Dominican Republic. Its use became widespread due to its alleged miraculous effects, much discussed by physicians and prominent victims, such as the humanist Ulrich von Hutten (1488–1523) [6]. The then widespread belief that remedies could be found where their target diseases originated is likely to have facilitated its entrance into the European pharmacopoeia. Guaiacum treatment requirements were diarrhoea induced by enemas and profuse sweating by resting for 40 days in a dark and British Journal of Clinical Pharmacology Br J Clin Pharmacol (2017) 83 2118–2119 2118


Journal of Computer Assisted Tomography | 2016

Application of a Colored Multiexposure High Dynamic Range Technique to Radiographic Imaging: An Experimental Trial to Show Feasibility.

Patrick Eppenberger; Magda Marcon; Michael Ho; Filippo Del Grande; Thomas Frauenfelder; Gustav Andreisek

Purpose The aim of this study was to evaluate the feasibility of applying the high dynamic range (HDR) technique to radiographic imaging to expand the dynamic range of conventional radiographic images using a colored multiexposure approach. Material and Methods An appropriate study object was repeatedly imaged using a range of different imaging parameters using a standard clinical x-ray unit. An underexposed image (acquired at 80 keV), an intermediate exposed image (110 keV), and an overexposed image (140 keV) were chosen and combined to a 32-bit colored HDR image. To display the resulting HDR image on a regular color display with typically 8 bits per channel, the Reinhard tone mapping algorithm was applied. The source images and the resulting HDR image were qualitatively evaluated by 5 independent radiologists with regard to the visibility of the different anatomic structures using a Likert scale (1, not visible, to 5, excellent visibility). Data were presented descriptively. Results High dynamic range postprocessing was possible without malalignment or image distortion. Application of the Reinhardt algorithm did not cause visible artifacts. Overall, postprocessing time was 7 minutes 10 seconds for the whole process. Visibility of anatomic structure was rated between 1 and 5, depending on the anatomic structure of interest. Most authors rated the HDR image best before individual source images. Conclusions This experimental trial showed the feasibility of applying the HDR technique to radiographic imaging to expand the dynamic range of conventional radiographic images using a colored multiexposure approach.


Radiology | 2012

Assessment of Median Nerve with MR Neurography by Using Diffusion-Tensor Imaging: Normative and Pathologic Diffusion Values

Roman Guggenberger; Daniel Markovic; Patrick Eppenberger; Avneesh Chhabra; Andreas Schiller; Daniel Nanz; Klaas Prüssmann; Gustav Andreisek


European Radiology Experimental | 2018

Radiological findings in ancient Egyptian canopic jars: comparing three standard clinical imaging modalities (x-rays, CT and MRI)

Patrick Eppenberger; Mislav Cavka; Michael E. Habicht; Francesco M. Galassi; Frank J. Rühli


Clinical Anatomy | 2018

The earliest known case of frontal sinus osteoma in man: The earliest case of frontal sinus osteoma

Roger Seiler; Lena M. Öhrström; Patrick Eppenberger; Dominic Gascho; Frank J. Rühli; Francesco M. Galassi

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Avneesh Chhabra

University of Texas Southwestern Medical Center

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