Publications by authors named "Michael Toepker"
Purpose: The aim of this study was to compare cancer detection by targeted fusion-guided biopsy with systematic biopsy, and to evaluate the value of combined biopsy, in a daily clinical practice scenario. Furthermore, we aimed to assess the influence of previous biopsies on cancer detection.
Methods: In this retrospective single-centre study, we evaluated 524 cases of combined biopsy of the prostate from October 2015 to December 2018.
Article Synopsis
- The study evaluates how different factors like stone size, composition, and iodine concentration affect the detection rate of kidney stones using dual-energy computed tomography (DE-CT) with virtual non-contrast (VNC) protocols.
- It was found that larger kidney stones (>2 mm) have a significantly higher detection rate than smaller stones, with the best results achieved at specific kilovoltage and iodine concentrations.
- Overall, while DE-CT protocols with lower contrast levels are effective for detecting larger stones, they are less reliable for identifying smaller stones.
Objectives: The aim of this study was to assess the objective and subjective image characteristics of monoenergetic images (MEI[+]), using a noise-optimized algorithm at different kiloelectron volts (keV) compared to polyenergetic images (PEI), in patients with pancreatic ductal adenocarcinoma (PDAC).
Methods: This retrospective, institutional review board-approved study included 45 patients (18 male, 27 female; mean age 66 years; range, 42-96 years) with PDAC who had undergone a dual-energy CT (DECT) of the abdomen for staging. One standard polyenergetic image (PEI) and five MEI(+) images in 10-keV intervals, ranging from 40 to 80 keV, were reconstructed.
Objectives: The aim was to investigate the image quality of dual-energy computed-tomography (DECT) compared to single-energy images at 80 kV and 140 kV in oral tumors.
Materials And Methods: Forty patients underwent a contrast-enhanced DECT scan on a definition flash-CT. Four reconstructions (80 kV, 140 kV, mixed (M), and optimum-contrast (OC)) were assessed by four blinded readers for subjective image quality (10-point scale/10=best).
Purpose: We evaluated a dual energy, split bolus computerized tomography protocol that provides virtual noncontrast, parenchymal and urographic phases in a single scan. We assessed the sensitivity of the virtual noncontrast phase using this protocol to detect urinary stones compared to the gold standard of the true noncontrast phase.
Materials And Methods: We prospectively enrolled in the study 81 patients who underwent unenhanced single energy computerized tomography at 120 kV/200 mA as well as contrast enhanced dual energy computerized tomography on a Somatom® Definition Flash-CT (tube A 80 kV/233 mA and tube B SN 140 kV/180 mA with 1/0.
Objective: The purpose of this study was to use second-generation dual-source CT to assess the influence of size, degree of stenosis, luminal contrast attenuation, and plaque geometry on stenosis quantification in a coronary artery phantom.
Materials And Methods: Six vessel phantoms with three outer diameters (2, 3, and 4 mm), each containing three radiolucent plaques (72.2 HU) that simulated eccentric and concentric 43.
Purpose: To retrospectively assess the detection rate for intracranial hematomas achieved with use of curved maximum intensity projections (MIPs) that parallel the inner table of the skull compared with the rate achieved by reading transverse sections of computed tomography (CT) only.
Materials And Methods: This retrospective study was approved by the institutional review board, which waived informed consent. A total of 314 consecutive patients who underwent CT for cranial trauma (155 male, 159 female; mean age ± standard deviation, 58 years ± 24 [range, 2-98 years]) were included.
Primary melanoma of the urinary bladder is a rare subentity of melanoma. The same applies for melanoma of the rhabdoid histopathologic phenotype. A female patient was initially diagnosed with melanoma of unknown origin caused by macroscopic lymph node metastasis in the left inguinal and parailiacal regions.
View Article and Find Full Text PDFBackground: Although chronic obstructive pulmonary disease (COPD) is amongst the leading causes of morbidity and mortality, no biomarkers for its early detection are known. We have recently demonstrated that COPD is accompanied by elevated serum heat shock protein (HSP) 27 levels as compared to a control population.
Objectives: In an open prospective study, we investigated whether elevated HSP27 levels are associated with the early radiological signs of COPD, i.
Purpose: To evaluate the reliability of attenuation values in virtual non-contrast images (VNC) reconstructed from contrast-enhanced, dual-energy scans performed on a second-generation dual-energy CT scanner, compared to single-energy, non-contrast images (TNC).
Materials And Methods: Sixteen phantoms containing a mixture of contrast agent and water at different attenuations (0-1400 HU) were investigated on a Definition Flash-CT scanner using a single-energy scan at 120 kV and a DE-CT protocol (100 kV/SN140 kV). For clinical assessment, 86 patients who received a dual-phase CT, containing an unenhanced single-energy scan at 120 kV and a contrast enhanced (110 ml Iomeron 400 mg/ml; 4 ml/s) DE-CT (100 kV/SN140 kV) in an arterial (n=43) or a venous phase, were retrospectively analyzed.
Objective: Cardiac computed tomography (CT) is a state-of-the-art technology that provides an accurate noninvasive method to quantify left ventricular mass for analysis of left ventricular hypertrophy (LVH). We aimed to examine seven ECG-based LVH criteria against two CT indexation criteria for LVH: a CT-specific body surface area cutoff and the obesity-independent height criteria.
Methods: In 333 patients (mean age 53 +/- 12 years, 61% men), 64-slice contrast-enhanced CT was performed and 12-lead surface ECG within 24 h.
Purpose: To determine the reproducibility, accuracy, and predictors of accuracy of computed tomography (CT) angiography to detect and characterize coronary atherosclerotic plaque as compared with intravascular ultrasound.
Methods: Ten ex vivo human coronary arteries were imaged in a moving phantom by dual-source CT (collimation: 0.6 mm, reconstructed slice thickness: 0.
Introduction: The purpose of this study was to compare a manual and automated 3D volume segmentation tool for evaluation of left atrial (LA) function by 64-slice multidetector-CT (MDCT).
Methods And Materials: In 33 patients with paroxysmal atrial fibrillation a MDCT scan was performed before radiofrequency-catheter ablation. Atrial function (minimal volume (LAmin), maximal volume (LAmax), stroke volume (SV), ejection fraction (EF)) was evaluated by two readers using a manual and an automatic tool and measurement time was evaluated.
Background: Aortic valve calcification (AVC) is associated with cardiovascular risk factors and coronary artery calcification. We sought to determine whether AVC is associated with the presence and extent of overall plaque burden, as well as to plaque composition (calcified, mixed, and noncalcified).
Methods: We examined 357 subjects (mean age 53 +/- 12 years, 61% male) who underwent contrast-enhanced electrocardiogram-gated 64-slice multidetector computed tomography from the ROMICAT trial for the assessment of presence and extent of coronary plaque burden according to the 17-coronary segment model and presence of AVC.
Purpose: We assessed the accuracy and reproducibility of non-calcified plaque quantification as simulated by a low-density stenosis in vessel phantoms using diameter and area measures, as well as the influence of vessel size and motion on quantification accuracy in dual-source computed tomography (DSCT).
Methods: Four phantoms (2, 2.5, 3, and 4 mm in luminal diameter) made from a radiopaque Lucite (126 +/- 23 Hounsfield units, HU) simulating a fixed radiolucent concentric coronary stenosis (7 +/- 2 HU, 50% luminal narrowing) were connected to a cardiac motion simulator.
Objective: Cardiac computed tomography allows for simultaneous assessment of left ventricular mass (LVM) and coronary artery disease (CAD). We aimed to determine whether LVM, LVM index (LVMi), and the left ventricular geometric pattern of concentric remodeling are associated with the extent of CAD in patients without left ventricular hypertrophy.
Methods: In 348 patients from the Rule Out Myocardial Infarction Using Computer Assisted Tomography trial, 64-slice computed tomography was performed and LVM measured at end-diastole.
Objectives: We aimed to identify the predictors of left atrial (LA) enlargement by multi-detector computed tomography (CT) and determine its association and predictive value for acute coronary syndrome (ACS).
Background: LA enlargement is associated with myocardial ischemia and coronary artery disease (CAD) and is a strong predictor for cardiovascular events. These studies were performed primarily with echocardiography.
Background: Left atrial (LA) volume is a predictor of cardiovascular events. Information on LA volume is available on contrast-enhanced electrocardiogram (EGC)-gated multidetector computed tomography (MDCT) scans.
Objective: To assess interobserver and intraobserver reproducibility of 3-dimensional threshold-based volume (3DTV) and 2-dimensional (2D) measurements for the assessment of LA volumes with contrast-enhanced cardiac 64-slice MDCT.
Objective: The aim of the study was to assess differences in the presence, extent, and composition of coronary atherosclerotic plaque burden as detected by coronary multidetector computed tomography (MDCT) between patients with and without diabetes mellitus.
Methods: We compared coronary atherosclerotic plaques (any plaque, calcified [CAP], non-calcified [NCAP, and mixed plaque [MCAP]]) between 144 symptomatic diabetic and non-diabetic patients (36 diabetics, mean age: 54.4+/-12, 64% females) who underwent coronary 64-slice MDCT (Siemens Medical Solutions, Forchheim, Germany) for the evaluation of acute chest pain but proven absence of myocardial ischemia.