Thomas Kahn

• Leipzig University

Purpose A fracture or a pseudarthrosis of the processus anterior calcanei (PAC) as well as a traumatized Os calcaneus secundarius (OCS) is often overlooked. A clinical or conventional radiological differentiation of these is uncertain. Therefore, a CT scan is recommended. The aim of the study was to identify CT morphological differentiators between...

Purpose The aim of this study was to compare Prostate Imaging Reporting and Data System (PI-RADS) versions v1 and v2 for the detection of prostate cancer (PCa) in multiparametric MRI (mpMRI) using whole-mount histological workup as reference standard. Material and methods MRI data of 40 patients with positive transrectal ultrasound-guided biopsy w...

Purpose To evaluate the technical and clinical utility of a fully MRI-compatible, pneumatically driven remote-controlled manipulator (RCM) for targeted biopsies of the prostate at 1.5 T. Materials and methods The data of the first 22 patients that were biopsied under robotic assistance were analyzed. Interventional planning relied on T2-weighted (...

Abstract Background The goal of our study was to evaluate the current approach in prediction of postoperative major complications after pancreaticoduodenectomy (PD), especially symptomatic pancreatic fistula (POPF), using parameters derived from computed tomography (CT). Methods Patients after PD were prospectively collected in a database of the lo...

Background The aim of this study was to investigate the effectiveness of the treatment of osteoid osteomas (OO) by radiofrequency ablation (RFA). In particular, the recurrence rate and the improvement in the quality of life as assessed by the reduction of pain intensity were evaluated. Methods Retrospective analysis of 26 patients after RFA of an...

Background Loss of skeletal muscle mass is a recognised complication with a prognostic impact in patients with cirrhosis. Aim To explore in a retrospective analysis which muscle compartment most reliably predicts the occurrence of cirrhosis‐associated complications and if there are gender‐related differences. Methods 795 patients with cirrhosis l...

Bariatric surgery and other therapeutic options for obese patients are often evaluated by the loss of weight, reduction of comorbidities or improved quality of life. However, little is currently known about potential therapy-related changes in the adipose tissue of obese patients. The aim of this study was therefore to quantify fat fraction (FF) an...

Introduction: MRI is an emerging method in obesity research for the quantification of fat content in various body regions. The aim of this study was to determine the accuracy of MR fat-water imaging and MR spectroscopy for fat quantification at 1.5 T in oil-in-water phantoms. Material and Methods: Oil-in-water emulsions were fabricated over the ent...

Objective Medical image processing tools in research are often developed from scratch without the use of predefined software structures, which potentially makes them less reliable and difficult to maintain. The objective here was to present and evaluate a novel framework (Dicomflex) for the deployment of tools with a uniform workflow, commonly enco...

Background/aims: The position of the tip of tunnelled haemodialysis (HD) catheters (THC) might influence flow characteristics during HD. In chest X-ray (CXR), carina-related landmarks may be practicable to verify the THC position, and tip-carina distance (TCD) might be useful to predict early-flow dysfunctions. Methods: In this single-centre, re...

Efficient image guidance is the basis for minimally invasive interventions. In comparison with X-ray, computed tomography (CT), or ultrasound imaging, magnetic resonance imaging (MRI) provides the best soft tissue contrast without ionizing radiation and is therefore predestined for procedural control. But MRI is also characterized by spatial constr...

Our purpose was to analyze associations between positron emission tomography (PET), diffusion weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging in patients with head and neck squamous cell carcinoma (HNSCC). The study involved 34 patients (9 women, 25 men, mean age: 56.7 ± 10.2 years). In all patients a simultaneous 18F-FDG-PET/MR...

Background MRI is attractive for guiding and monitoring interventional procedures due to its high intrinsic soft tissue contrast and the possibility to measure flow and cardiac function. Methods Technical solutions have been developed for all procedural steps including imaging guidance, MR-safe catheters and instruments and patient monitoring. This...

Background MRI is attractive for the guiding and monitoring of interventional procedures due to its high intrinsic soft tissue contrast and the possibility to measure physiologic parameters like flow and cardiac function. Method The current status of interventional MRI for the clinical routine was analyzed. Results The effort needed for the develop...

Purpose Analysis of patient´s X-ray exposure during percutaneous radiologic gastrostomies (PRG) in a larger population. Materials and Methods Data of primary successful PRG-procedures, performed between 2004 and 2015 in 146 patients, were analyzed regarding the exposition to X-ray. Dose-area-product (DAP), dose-length-product (DLP) respectively, an...

Cardiac hematological malignancies (CHMs) are rare entities and comprise lymphoma, leukemic infiltration, and extramedullary manifestation of multiple myeloma. The aim of this work is to summarize typical growth patterns, imaging features, and outcome parameters of CHM. Overall, 12 cases from 4 centers were reviewed retrospectively together with 60...

Background and method: Incidental cardiovascular findings are a frequent phenomenon in computed tomography (CT) examinations. As the result of a dedicated PubMed search this article gives a systemic overview of the current literature on the most important incidental cardiovascular findings, their prevalence and clinical relevance. Results: The m...

Introduction: Systemic air embolism (SAE) is a rare but serious complication following endoscopic procedures. It may occur with or without direct vessel injury. The aim of this work is to review cases of SAE following endoscopy without proven vessel injury. Methods: In this systematic review PubMed database was screened for SAE following endosco...

Background: Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) can characterize perfusion and vascularization of tissues. DCE MRI parameters can differentiate between malignant and benign lesions and predict tumor grading. The purpose of this study was to correlate DCE MRI findings and various histopathological parameters in head and n...

This work aims to assess the impact of an additional endorectal coil on image quality and cancer detection rate within the same patients. At a single academic medical center, this transversal study included 41 men who underwent T2- and diffusion-weighted imaging at 3 T using surface coils only or in combination with an endorectal coil in the same s...

Purpose: Radiology represents a highly relevant part of undergraduate medical education from preclinical studies to subinternship training. It is therefore important to establish a content base for teaching radiology in German Medical Faculties. Materials and Methods: The German Society of Radiology (DRG) developed a model curriculum for radiologic...

Purpose To compare single-shot echo-planar diffusion-weighted imaging-derived apparent diffusion coefficient (ADC) maps with fat-saturated (FS) proton density (PD)-weighted turbo spin-echo (TSE) imaging in the detection of bone marrow lesions (BMLs) after knee trauma. Materials and Methods Institutional review board approval was obtained from Leipz...

Background: Even if lower vaginal delivery success rates and impaired neonatal short-term outcomes have been reported for primiparous women with breech presentation, vaginal breech delivery remains an option for carefully selected patients. Because Magnetic resonance imaging (MRI) pelvimetry can provide additional information on maternal pelvic mo...

Objectives: To analyze possible associations between functional simultaneous (18)F-FDG-PET/MR imaging parameters and histopathological parameters in head and neck squamous cell carcinoma (HNSCC). Material and methods: 11 patients (2 female, 9 male; mean age 56.0years) with biopsy-proven primary HNSCC underwent simultaneous (18)F-FDG-PET/MRI with...

Background The 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) procedure is a cornerstone in the diagnostics of head and neck cancers. Several years ago PET-magnetic resonance imaging (PET/MRI) also became available as an alternative hybrid multimodal imaging method. Objective Does PET/MRI have advantages ov...

Methods: In a prospective study, 30 patients with a previous inconclusive MRI and suspected spondylodiscitis underwent combined (18)F-FDG-PET/MRI, including standard spine MRI sequences pre- and post-contrast. The image datasets were evaluated on dedicated workstations by two radiology residents and one board-certified nuclear medicine physician i...

Zielsetzung: Ziel dieser Untersuchung war die Analyse von Flussstorungen wahrend der Haemodialyse mit getunnelten ein- oder zweilumigen Vorhofdialysekathetern als Fruhkomplikation innerhalb von 10 Tagen nach Implantation in Abhangigkeit exakter Lageparameter. Fur getunnelte Dialysekatheter gilt die Empfehlung einer intraatrialen Lage und der, wenn...

Image-based quantifications of visceral adipose tissue (VAT) volumes from segmented VAT areas are increasingly considered for risk assessment in obese patients. The goal of this study was to determine the power of partial VAT areas to predict total VAT volume in morbidly obese patients (BMI > 40 kg/m2) as a function of gender, age and anatomical la...

Background: There is a huge variety of image guided local ablation technique to treat primary and secondary liver cancer. While thermal ablations are most common, these modalities have some limitations like coagulation necrosis to adjacent structures or undesired heat sink near to larger vessels. This indicates the need of alternative techniques to...

BACKGROUND Multiparametric mpMRI has substantially improved the detection of clinically significant prostate cancer (PCa) and the confidence in benign and insignificant findings. The latest PI-RADS v2 guideline relies on T2-weighted, diffusion-weighted and dynamic contrast enhancement imaging (T2W, DWI, DCE). We report on features and benefits of a...

Objectives: To evaluate clinical effectiveness and diagnostic efficiency of a navigation device for MR-guided biopsies of focal liver lesions in a closed-bore scanner. Methods: In 52 patients, 55 biopsies were performed. An add-on MR navigation system with optical instrument tracking was used for image guidance and biopsy device insertion outsid...

Objectives: Previous non-simultaneous PET/MR studies have shown heterogeneous results about the correlation between standardized uptake values (SUVs) and apparent diffusion coefficients (ADCs). The aim of this study was to investigate correlations in patients with primary and recurrent tumors using a simultaneous PET/MRI system which could lead to...

In recent years ischemic stroke caused by an intracranial vessel occlusion has become a treatable disease. Over decades intravenous thrombolysis by recombinant tissue plasminogen activator was the only accepted causal treatment of ischemic stroke supported by the results of randomized, controlled trials. However, there has been continuous developme...

Objective: To demonstrate the feasibility of simultaneous acquisition of 18F-FDG-PET, diffusion-weighted imaging (DWI) and T1-weighted dynamic contrast-enhanced MRI (T1w-DCE) in an integrated simultaneous PET/MRI in patients with head and neck squamous cell cancer (HNSCC) and to investigate possible correlations between these parameters. Methods:...

Imaging of cervical carcinoma remains challenging as local infiltration of surrounding tissues cannot always be discriminated safely. New imaging techniques, like diffusion-weighted imaging (DWI) have emerged, which could lead to a more sensitive tumor detection. To evaluate the benefits of DWI for determination of size, local infiltration, and tum...

Objectives: MRI is of great clinical utility for the guidance of special diagnostic and therapeutic interventions. The majority of such procedures are performed iteratively ("in-and-out") in standard, closed-bore MRI systems with control imaging inside the bore and needle adjustments outside the bore. The fundamental limitations of such an approac...

Purpose: This prospective study compared a manual program for liver volumetry with semiautomated software. The hypothesis was that the semiautomated software would be faster, more accurate and less dependent on the evaluator’s experience. Materials and Methods: Ten patients undergoing hemihepatectomy were included in this IRB approved study after w...

Diffusion-weighted imaging (DWI) provides essential information regarding tumor composition, such as cellularity and/or perfusion. DWI is helpful in distinguishing between malignant and benign lesions. Malignant intramuscular/soft tissue lesions consist of a wide spectrum of tumors that have different cell counts and matrix. It is presumed that the...

Chest radiography is the most common diagnostic modality in intensive care units with new mobile flat-panels gaining more attention and availability in addition to the already used storage phosphor plates. Comparison of the image quality of mobile flat-panels and needle-image plate storage phosphor system in terms of bedside chest radiography. Retr...

Zielsetzung: Das viszerale Fettgewebe (VAT) gilt als Risikofaktor fur diverse metabolische Erkrankungen. Die MRT-basierte Quantifizierung des VAT-Volumens erfordert in der Regel eine zeitaufwandige Segmentierung dutzender Einzelschichten. An der Patientenkohorte eines bestehenden Forschungs- und Behandlungsprogramms zur Adipositas sollte geklart we...

Zielsetzung: Vergleich der Bildqualitat von mobilen Flachdetektoren und Speicherfoliensystemen mit Nadelkristalldetektoren bei Thoraxbettaufnahmen. Material und Methodik: Es wurden retrospektiv 84 Thoraxaufnahmen von 42 Patienten (20 w., 22 m.; Durchschnittsalter: 65J.) einer chirurgischen Intensivstation ausgewertet. Die Aufnahmen erfolgten im Rah...

The quantification of visceral adipose tissue (VAT) is increasingly being considered for risk assessment and treatment monitoring in obese patients, but is generally time-consuming. The goals of this work were to semi-automatically segment and quantify VAT areas of MRI slices at previously proposed anatomical landmarks and to evaluate their predict...

Die perkutane Radiofrequenzablation (RFA) ist ein minimalinvasives Verfahren zur thermischen Koagulation von Tumorgewebe und stellt somit eine Alternative zur chirurgischen Entfernung dar. Die Erhitzung wird durch ein elektromagnetisches Wechselfeld erreicht, welches über eine spezielle Nadelanordnung im Gewebe erzeugt wird. Nach der Intervention w...

PURPOSE Abdominal fat, in particular visceral adipose tissue (VAT), is associated with an increased risk for metabolic and cardiovascular diseases. MRI is well suited for volumetry but data processing is typically laborious and time-consuming. The goal was to evaluate how fast and how accurate a heavily reduced analysis can predict total abdominal...

PURPOSE Quantitative, image-based assessments of lesion volume and shape improve the correctness of follow-up reports and potentially influence therapeutical decisions but are usually laborious and time-consuming. The goal was to assess the clinical feasibility of a novel real-time CT segmentation tool on thermally induced liver lesions. METHOD AN...

CONCLUSION The presented software enables visualization and quantification of various fat depots and is considered a valuable tool to assess disease conditions and monitor related interventions. BACKGROUND With obesity-related diseases, such as type 2 diabetes, on the rise, quantification of visceral and subcutaneous adipose tissue (VAT, SAT) volu...

Objectives To compare 64-slice contrast-enhanced computed tomography (CT) with 3-Tesla magnetic resonance imaging (MRI) using Gd-EOB-DTPA for the diagnosis of hepatocellular carcinoma (HCC) and evaluate the utility of diffusion-weighted imaging (DWI) in this setting. Methods 3-phase-liver-CT was performed in fifty patients (42 male, 8 female) with...

Subcutaneous (SAT) and visceral adipose tissue (VAT) differ in composition, endocrine function and localization in the body. VAT is considered to play a role in the pathogenesis of insulin resistance, type 2 diabetes, fatty liver disease, and other obesity-related disorders. It has been shown that the amount, distribution, and (cellular) compositio...

BACKGROUND: Spondylosclerosis hemispherica is a rare syndrome of the spine and was described first by Dihlmann. The typical radiographic appearance is a hemispherical sclerosis of the vertebral body, which is accompanied by pain in the affected region. Usually it appears at the lower lumbar spine. The etiology varies and includes degenerative disk...

Die isolierte Ruptur des Hoffa-Fettkorpers ist ausgesprochen selten [1]. Ursachlich ist zumeist ein direkter Schlag auf die Infrapatellarregion oder ein Hyperextensionstrauma mit Kompression des Fettkorpers zwischen Femurkondylen und Tibiaplateau. Der Fallbeschreibung entsprechend besteht die klinische Relevanz traumatischer Verletzungen des Hoffa-...

Die Quantifizierung des Fettvolumens gewinnt fur die Prognose und das Therapiemonitoring der Adipositas und metabolischer Begleiterkrankungen zunehmend an Bedeutung. Eine automatisierte Segmentierung des viszeralen Fettgewebes (VAT) mithilfe der MRT beruht meist auf einer Schwellwertanalyse der T1-gewichteten Signale (Histogramm). Ziel dieser Studi...

Ziel der Studie war die Evaluation einer Software zur automatischen Lebervolumetrie (LV) im Vergleich zur manuellen Methodik. Bei 10 Pat. (mittl. Alter:70J.,6?,? 4) wurde ein Leber-CT mit Iopromid im Rahmen der OP-Vorbereitung zur Hemihepatektomie durchgefuhrt. Anhand der pv-Phase wurde die Leber manuell u. mittels automatischer Software von 6 Ausw...

Non-invasive assessment of steatosis and fibrosis is of growing relevance in non-alcoholic fatty liver disease (NAFLD). 1H-Magnetic resonance spectroscopy (1H-MRS) and the ultrasound-based controlled attenuation parameter (CAP) correlate with biopsy proven steatosis, but have not been correlated with each other so far. We therefore performed a head...