Tilo Niemann

Kantonsspital Baden · Department of Radiology

Refraction-based x-ray imaging can overcome the fundamental contrast limit of computed tomography (CT), particularly in soft tissue, but so far has been constrained to high-dose ex vivo applications or required highly coherent x-ray sources, such as synchrotrons. Here we demonstrate that grating interferometry (GI) is more dose efficient than conve...

Background/aim: To evaluate the impact of high data rate and sampling frequency detector technology compared to standard scan equipment on the image quality in abdominal computed tomography (CT) of overweight and obese patients. Patients and methods: A total of 173 patients were retrospectively included in this study. Objective image quality in...

Background/aim: The aim was to evaluate the effect of a combined precision matrix and high sampling rate on the delineation of anatomical structures and objective image quality in single source CT in a qualitative approach. Materials and methods: An anthropomorphic thoracic phantom was used to evaluate the objective image quality parameters, inc...

For a century, clinical X-ray imaging has visualised only the attenuation properties of tissue, which fundamentally limits the contrast, particularly in soft tissues like the breast. Imaging based on refraction can overcome this limitation, but so far has been constrained to high-dose ex-vivo applications or required highly coherent X-ray sources,...

Objectives: Different computed tomography (CT) scanners, variations in acquisition protocols, and technical parameters employed for image reconstruction may introduce bias in the analysis of pericoronary adipose tissue (PCAT) attenuation derived from coronary computed tomography angiography (CCTA). Therefore, the aim of this study was to establish...

In this paper, we describe the development and evaluation of a novel tissue-holding device (THD) for use during robotic-assisted laparoscopic partial nephrectomy. The THD is a vacuum-based apparatus made of either 3D-printed polyethylene or stainless steel. The proximal end connects to suction tubing routed outside the body, while the distal end is...

For the first time, a large and well-preserved tusk of a late-glacial mammoth from central Switzerland was examined in toto with use of a clinical scanning device featuring an improved design with an 82-cm-wide bore (SOMATOM X.ceed, Siemens Healthineers). The CT scans showed annual increments of dentin apposition from the central canal. A total of...

Background/aim: To assess the diagnostic performance of reverse transcriptase polymerase chain reaction (RT-PCR), low-dose chest computed tomography (CT), and serological testing, alone and in combinations, as well as routine inflammatory markers in patients evaluated for COVID-19 during the first wave in early 2020. Patients and methods: We ret...

Background: Lung cancer is the leading cause of cancer-related deaths in Switzerland. Despite this, there is no lung cancer screening program in the country. In the United States, low-dose computed tomography (LDCT) lung cancer screening is partially established and endorsed by guidelines. Moreover, evidence is growing that screening reduces lung...

Background: Laparoscopic surgery (LS) requires CO2 insufflation to establish the operative field. Patients with worsening pain post-operatively often undergo computed tomography (CT). CT is highly sensitive in detecting free air-the hallmark sign of a bowel injury. Yet, the clinical significance of free air is often confounded by residual CO2 and...

Background/aim: The effective atomic number (Zeff) and electron density relative to water (ρe or Rho) of elements can be derived in dual-energy computed tomography (DECT). The aim of this phantom study was to investigate the effect of different photon energies, radiation doses, and reconstruction kernels on Zeff and Rho measured in DECT. Material...

Follow-up is essential for the early detection of recurrent non-muscle invasive bladder cancers (NMIBC). This study investigates the clinical relevance of new diagnostic tools such as an mRNA-based urine test (XPERT© Bladder Cancer Monitor, XBCM) and Narrow Band Imaging© (NBI) and compares them with the established follow-up diagnostics (white-ligh...

Background/aim: Multiparametric dual energy comptuted tomography (CT) imaging allows for multidimensional tissue characterization beyond the measurement of Hounsfield units. The purpose of this study was to evaluate multiple imaging parameters for different abdominal organs in dual energy CT (DECT) and analyze the effects of the contrast agent on...

Background/aim: The quantitative evaluation of fat tissue, mainly for the determination of liver steatosis, is possible by using dual-energy computed tomography. Different photon energy acquisitions allow for estimation of attenuation coefficients. The effect of variation in radiation doses and reconstruction kernels on fat fraction estimation was...

The COVID-19 pandemic has challenged institutions’ diagnostic processes worldwide. The aim of this study was to assess the feasibility of an artificial intelligence (AI)-based software tool that automatically evaluates chest computed tomography for findings of suspected COVID-19. Two groups were retrospectively evaluated for COVID-19-associated gro...

Background Contrast-to-noise ratio is used to objectively evaluate image quality in chest computed tomography angiography (CTA). Different authors define and measure contrast-to-noise ratio using different methods. Purpose To summarize and evaluate the different contrast-to-noise ratio calculation formulas in the current literature. Material and...

Introduction: Occurrence of urinary calculi is a common medical condition. Since treatment and prevention measures depend on the type of stone found, reliable diagnostic tools are required. Dual energy computed tomography (CT) allows for rough classification of the stones found. After extraction, stone composition can be confirmed by laboratory an...

Background Presence of right ventricular thrombus (RVT) is a rare but life-threatening condition, thus immediate diagnosis and therapy are mandatory. Unfortunately, detection and distinction from intraventricular tumor masses or vegetations represents a complex task. Furthermore, consecutive therapy is principally led by clinical presentation witho...

Background The COVID-19 pandemic challenges the recommendations for patients’ preoperative assessment for preventing severe acute respiratory syndrome coronavirus type 2 transmission and COVID-19-associated postoperative complications and morbidities. Purpose To evaluate the contribution of chest computed tomography for preoperatively assessing pa...

Objective Laparoscopic surgery improves the postoperative recovery process and relies on CO2 insufflation to establish the operative field. Most residual CO2 is expelled prior to port and incision closure. Computed tomography (CT) is often used to assess an acute abdomen and is highly sensitive in detecting free intra-abdominal air – the hallmark s...

Objective: To extract pulmonary and cardiovascular metrics from chest CTs of patients with coronavirus disease 2019 (COVID-19) using a fully automated deep learning-based approach and assess their potential to predict patient management. Materials and methods: All initial chest CTs of patients who tested positive for severe acute respiratory syn...

Background Dual-energy computed tomography allows for improved organ characterization by applying two different X-ray energy spectra. Purpose To evaluate the postmortem unenhanced DECT scans of human livers with histologically determined stages of hepatic steatosis; to measure hepatic attenuation, effective atomic number, electron density, fat fra...

Objectives: The aim of this study was to compare a compressed-sensing free-breathing VIBE (fbVIBE) with a conventional breath-hold VIBE (bhVIBE) for dynamic contrast-enhanced imaging of the upper abdomen. Materials and methods: In total, 70 datasets (bhVIBE, n = 30; fbVIBE n = 40; hard-gated [hg] reconstruction, n = 30; motion-state-resolved [mr...

The aim of this study is to evaluate the influence of reconstruction parameters from CT raw data on the quality and time consume/ efficacy of CRT reconstructions.

Objective: Cinematic rendering technique is used to generate almost photorealistic 3D reconstructions of volumetric data. The purpose of this study was to evaluate the feasibility of cinematically rendered reconstructions in routine CT examinations of ankle sprains. Conclusion: Cinematic rendering technique may be primarily used to deliver visua...

Objective: To evaluate the accuracy of semiautomated segmentation of urinary stone size in CT compared to manual measurement. Materials and methods: A total of 103 patients (32f, 71m ; mean age 52 years±18 that were diagnosed with urolithiasis and collected stones received standardized ex vivo CT-scans and radiography of the stones. Stone size w...

Purpose To evaluate whether gadolinium penetrates human cerebrospinal fluid (CSF) after MR imaging (MRI) with a gadolinium-based contrast agent (GBCA). Materials and Methods For this retrospective study, the authors analyzed 60 CSF samples from 57 patients (median age, 50 years; range, 3-92 years) who underwent one contrast material-enhanced MRI ex...

Myocardial Clefts - Incidental Findings in Parainfectious Myocarditis Abstract. We report a 23-year-old woman with parainfectious myocarditis due to gastroenteritis. A transthoracic echocardio-graphy revealed a recess in the left inferobasal ventricle. For further investigation, cardiac magnetic resonance imaging was initiated, which revealed a myo...

Background: Metal artifacts from retained bullets impair the image quality on computed tomography (CT) and may compromise the detection of critical lesions or the bullet path. To reduce metallic artifacts from medical implants on CT, special algorithms have been developed, e.g., iterative metal artifact reduction (iMAR). The aim of this prospectiv...

Post-mortem computed tomography (PMCT) has become a standard procedure in many forensic institutes worldwide. However, the standard scan protocols offered by vendors are optimised for clinical radiology and its main considerations regarding computed tomography (CT), namely, radiation exposure and motion artefacts. Thus, these protocols aim at low-d...

Rationale: The gold standard for detection of axillary sentinel lymph nodes uses injection of a radioisotope (99Tc Nanocoll). As an alternative to this method, a magnetometer detecting the superparamagnetic tracer Sienna+® can be applied for detection of sentinel lymph nodes. The goal of this study was to determine whether interpretation of breast...

We present a 15-year-old male patient with persistent localized pain on the dorsal side of the left wrist between the base of the 2nd and 3rd metacarpal bones and over the third carpometacarpal joint. It was diagnosed as an accessory metacarpal bone -Os styloideum. This entity may be detected on plain radiographs and in ultrasound examination and i...

Introduction Sentinel lymph node biopsy (SLNB) is the standard technique used in patients with early breast cancer without clinical signs of axillary lymph node metastases. The current standard for detection of axillary sentinel lymph nodes is the injection of a radioactive 99 Technetium tracer either alone or combined with a blue dye. As an altern...

Zusammenfassung. Wir berichten über den Fall eines 84-jährigen Patienten mit rezidivierenden Stürzen, der ein traumatisch bedingtes Hämatom des Septum pellucidum nach Kopfanprall erlitt. Wir erläutern die embryologische Entwicklung des Septums und dadurch bedingte mögliche Pathomechanismen bei Trauma. Die bildgebende Diagnose mittels Computertomogr...

Objectives: Organ-based tube current modulation aims to reduce exposure to radiosensitive organs like the breasts by considering their anatomical location and altering tube current during rotation. Former phantom studies demonstrated a dose reduction of 20-37 %. Our study aimed to estimate the potential of dose reduction with this technique in rel...

Background: The increasing absolute number of paediatric CT scans raises concern about the safety and efficacy and the effects of consecutive diagnostic ionising radiation. Objective: To demonstrate a method to evaluate the lifetime attributable risk of cancer incidence/mortality due to a single low-dose helical chest CT in a two-year patient co...

Background: Before introducing 70-kVp settings in the low-kilovoltage strategies for pediatric examinations, it was mandatory to demonstrate, at similar dose levels, an equivalence of image quality at 70 kVp and 80 kVp. Objective: To assess image quality of chest CT examinations acquired at 70 kVp in comparison with standard scanning at 80 kVp....

The term «crazy paving» describes an unspecific pattern in thoracic computed-tomography mimicking a paving stone configuration. This pattern can be caused by a number of differential diagnosis, for example alveolar hemorrhage, alveolar proteinosis, lipoid pneumonia or adenocarcinoma in situ. The knowledge of the correlation between imaging findings...

Ein 28-jahriger Patient wurde vom Hausarzt mit kardialer Belastungsdyspnoe (NYHA III) sowie thorakalem Druckgefuhl uberwiesen. Zudem bestand eine arterielle Hypertonie. Der Patient berichtete uber chronischen Reizhusten mit weislichem Auswurf. Drei Monate zuvor war er bei gleicher Symptomatik bereits mit der Verdachtsdiagnose einer Myokarditis hosp...

The discussion about setting up a program for lung cancer screening was launched with the publication of the results of the National Lung Screening Trial, which suggested reduced mortality in high-risk subjects undergoing CT screening. However, important questions about the benefit-harm balance and the details of a screening program and its cost-ef...

To evaluate the clinical impact of automatic tube voltage selection on chest CT angiography (CTA). Ninety-three patients were prospectively evaluated with a CT protocol aimed at comparing two successive CTAs acquired under similar technical conditions except for the kV selection: (1) the initial CTA was systematically obtained at 120 kVp and 90 ref...

Background: The principal concern of any radiation exposure in computed tomography (CT) is the induction of stochastic risks of developing a radiation-induced cancer. The results given in this manuscript will allow to (re-)calculate yield of chest CT. Purpose: To demonstrate a method to evaluate the lifetime attributable risk (LAR) of cancer inc...

PURPOSE To evaluate image quality of pediatric chest CT acquired at 70 kV in comparison with standard scanning at 80 kV. METHOD AND MATERIALS Seventy-eight consecutive pediatric patients (≤15 years) undergoing chest CT studies on a dual-source CT system (Definition Flash; Siemens) were prospectively evaluated with a 70-kV scanning protocol. All sc...

An ossification of the posterior longitudinal ligament, often presenting asymptomatically, can cause a symptomatic myelopathy after trauma. Keeping this entity in mind in daily clinical routine will help in making the correct diagnosis and in administering the corresponding therapy.

How does an acquisition at reduced doses using automatic tube current modulation techniques compare to the normal standard dose CT? Does it affect the sensitivity for detection of calcifications? CT raw data of 54 patients with suspected urolithiasis acquired with automatic tube current modulation techniques were used for image noise simulations wi...

Two patients, each with a history of multiple cancers, were referred to our institution for routine cancer staging. Contrast enhanced multislice-CT showed round and oval shaped inguinal and retroperitoneal masses in one patient and inguinal mass lesions in the other patient. The mass lesions were suspicious of lymphadenopathy related to cancer recu...

Objective To give a comprehensive overview of fetal doses reported in the literature when imaging the pregnant woman with suspected pulmonary embolism (PE). Methods A comprehensive literature search in the PubMed, MEDLINE and EMBASE databases yielded a total of 1,687 papers that were included in the analysis and have been analysed with regard to f...

Schistosomiasis is a helminthic infection that is endemic in tropical and subtropical regions. Pulmonary involvement can be divided into two categories: acute or chronic compromise. Chronic and recurrent infection develops in persons living or travelling in endemic areas. In the lungs, granuloma formation and fibrosis around the schistosome eggs re...

Ziele: Ziel dieser Arbeit ist eine systematische Analyse der Literatur uber fetale Dosen im Zusammenhang mit radiologischer Bildgebung bei suspizierter Lungenembolie (LE) in der Schwangerschaft. Methode: Eine systematische Literatursuche wurde in den Pubmed, Medline und Embase Datenbanken durchgefuhrt. Das Ergebnis lieferte 1687 Artikel, die mit Bl...

Die Wernicke-Enzephalopathie ist eine akute neurologische Erkrankung, welche durch einen Vitamin-B1-Mangel verursacht wird und ohne prompte Therapie eine betrachtliche Morbiditat und Mortalitat hat. Anhand eines Fallberichtes wird auf die fur eine radiologische Diagnostik wichtigen und typischen Signalveranderungen in der MRT ausfuhrlich eingegange...

Wernicke encephalopathy is a neurological disorder, often caused by a lack of thiamine. Immediate diagnosis and therapy are important to prevent significant morbidity and mortality. Based on a clinical case radiologic imaging features on MRI are demonstrated.

The central pontine and extrapontine myelinolysis is an important entity in the neurology disorders in the context with alcohol abuse. Though often first based on clinical characteristics, the diagnosis can be often supported with radiologic imaging.

Die zentrale pontine und extrapontine Myelinolyse ist ein wichtiges Krankheitsbild im Zusammenhang mit chronischem Alkoholkonsum oder mit schweren Elektrolytdysbalancen. Obwohl oftmals zunachst eine klinische Verdachtsdiagnose gestellt wird, ist es mittels radiologischer Bildgebung gut moglich, diese Diagnose zu unterstutzen.

Radiation protection is a major issue since the implementation of MSCT technology and its widespread indication for the detection of various diseases. In a European-wide trial (SECT) meta-analyses of imaging alternatives to CT have been initiated. This paper focuses on the diagnostic performance of transthoracic ultrasound (TUS) for the diagnosis o...

The objective of this work was to evaluate the influence of the postprocessing tool Diamond View (Siemens AG Medical Solutions, Germany) on image quality in conventional chest radiography. Evaluation of image quality remains a challenge in conventional radiography. Based on the European Commission quality criteria we evaluated the improvement of im...

The objective of our study was to perform a meta-analysis to evaluate the diagnostic performance of low-dose CT for the diagnosis of urolithiasis (seven studies, 1,061 patients). The medical literature from 1995 to 2007 was searched using PubMed, Medline, and Cochrane Library databases for articles on studies that used low-dose CT (< 3 mSv dose app...

Conventional radiography contributes for the majority of examinations in radiology departments. Based on the European Commission Quality Criteria we evaluated the effects on image quality when applying the new post-processing tool Diamond View (Siemens AG Medical Solutions, Germany) to conventional lumbar spine radiographs. 100 digital image pairs...

Lipomatous hypertrophy of the interatrial septum (LHIS) is a benign disorder characterized by a fatty accumulation in the interatrial septum. It typically occurs in obese, elderly patients and may cause arrhythmias. In this report we present the case of an oncology patient with metastasis of unknown origin and a fatty mass of the interatrial septum...

As definition, a "kissing" osteochondroma is a typical new bony formation with erosion on the adjacent paired bone, provoked by pressure of the outgrowth. Further diagnostics for incidentally diagnosed solitary osteochondroma should be performed only in cases where malignant transformation is suspected.

Ein kissing Osteochondrom ist eine typische Knochenformation mit Erosion eines benachbarten Knochens, die durch den mechanischen Druck des Tumors bedingt ist. In der Literatur existiert keine radiologische Definition des Begriffes kissing. Die meisten Autoren beziehen sich auf Läsionen, die eine benachbarte knöcherne Struktur oder andere knöcherne...

Wir berichten über einen Patienten mittleren Alters mit gürtelförmigen Oberbauchschmerzen, bei welchem nebst einer chronischen zusätzlich eine subakute Thrombose der kavernös transformierten und stark verkalkten Portalvene duplexsonographisch und computertomographisch nachgewiesen wurde. Eine Vollliqueminisierung und anschliessende Marcoumarisierun...

Aussagen in radiologischen Befunden uber die Dignitat asymptomatischer interkostaler Raumforderungen sind mit Vorsicht zu treffen. Auch radiologisch zunachst benigne erscheinende Lasionen konnen sich, wie in beiden vorliegenden Fallen, als bosartig entpuppen. Metastasen eines malignen Melanoms konnen sich atypisch prasentieren und dadurch leicht ve...

Das Ziel dieser Arbeit ist der klinische Einsatz digitaler radiostereometrischer Analyse (RSA) als diagnostische Messmethode zur Erkennung früher postoperativer aseptischer Lockerungszeichen der tibialen Plateaus von Totalknieendoprothesen des Typs NexGen® LPS im Vergleich mit der Verwendung zweier verschiedener Zementtypen – dem niedrigviskösen St...