A5008508081- Advanced X-ray and CT Imaging
- Radiation Dose and Imaging
- Medical Imaging Techniques and Applications
- Bone health and osteoporosis research
- Dental Radiography and Imaging
- Medical Imaging and Analysis
- Radiomics and Machine Learning in Medical Imaging
- Spinal Fractures and Fixation Techniques
- Shoulder Injury and Treatment
- Bone Tumor Diagnosis and Treatments
- Shoulder and Clavicle Injuries
- Sarcoma Diagnosis and Treatment
- Spine and Intervertebral Disc Pathology
- Nuclear Physics and Applications
- Ultrasound in Clinical Applications
- Pelvic and Acetabular Injuries
- Aortic aneurysm repair treatments
- Cardiac Imaging and Diagnostics
- Brain Tumor Detection and Classification
- Photoacoustic and Ultrasonic Imaging
- Orthopedic Surgery and Rehabilitation
- Medical Imaging and Pathology Studies
- Urban Heat Island Mitigation
- Astrophysical Phenomena and Observations
- Medical Image Segmentation Techniques
Klinikum rechts der Isar
2015-2023
Technical University of Munich
2015-2023
München Klinik
2018
University Radiology
2018
Purpose To investigate the feasibility of using spectral photon-counting computed tomography (CT) to differentiate between gadolinium-based and nonionic iodine-based contrast material in a colon phantom by characteristic k edge gadolinium. Materials Methods A custom-made was filled with material, gadolinium-filled capsule representing material-enhanced polyp positioned on wall. The scanned preclinical CT system obtain conventional data. By fully multibin information, decomposition performed...
Disorders of the lungs such as chronic obstructive pulmonary disease (COPD) are a major cause morbidity and mortality third leading death in world. The absence sensitive diagnostic tests for early stages COPD results under-diagnosis this treatable an estimated 60–85% patients. In recent years grating-based approach to X-ray dark-field contrast imaging has shown be very detection quantification emphysema small animal models. However, translation technique systems suitable humans remains...
After endovascular aortic repair (EVAR), discrimination of endoleaks and intra-aneurysmatic calcifications within the aneurysm often requires multiphase computed tomography (CT). Spectral photon-counting CT (SPCCT) in combination with a two-contrast agent injection protocol may provide reliable detection single acquisition. To evaluate feasibility SPCCT, stent-lined compartment an abdominal phantom was filled mixture iodine gadolinium mimicking enhanced blood. represent different flow rates,...
Abstract The performance of a recently introduced spectral computed tomography system based on dual‐layer detector has been investigated. A semi‐anthropomorphic abdomen phantom for CT evaluation was imaged the at different radiation exposure levels ( CTDI vol 10 mG y, 20 y and 30 y). equipped with specific low‐contrast tissue‐equivalent inserts including water‐, adipose‐, muscle‐, liver‐, bone‐like materials variation in iodine concentrations. Additionally, size varied using extension rings...
To assess the feasibility of dual-contrast spectral photon-counting computed tomography (SPCCT) for liver imaging.We present an SPCCT in-silico study simultaneous mapping complementary distribution in two contrast agents (CAs) subsequently intravenously injected: a gadolinium-based agent and iodine-based agent. Four types simulated lesions with characteristic arterial portal venous pattern (haemangioma, hepatocellular carcinoma, cyst, metastasis) are presented. A material decomposition was...
The purpose of this study was to investigate a preclinical spectral photon-counting CT (SPCCT) prototype compared conventional for pulmonary imaging. A custom-made lung phantom, including nodules different sizes and shapes, scanned with SPCCT in standard high-resolution (HR-CT) mode. Volume estimation evaluated by linear regression. Shape similarity the Dice coefficient. Spatial resolution investigated via MTF each imaging system. In-vivo rabbit images from system were subjectively reviewed....
To investigate the in vivo applicability of non-contrast-enhanced hydroxyapatite (HA)-specific bone mineral density (BMD) measurements based on dual-layer CT (DLCT).A spine phantom containing three artificial vertebral bodies with known HA densities was measured to obtain spectral data using DLCT and quantitative (QCT), simulating different patient positions grades obesity. BMD calculated from virtual monoenergetic images at 50 200 keV. HA-specific values 174 vertebrae 33 patients (66 ± 18...
Osteoporosis diagnosis using multidetector CT (MDCT) is limited to relatively high radiation exposure. We investigated the effect of simulated ultra-low-dose protocols on in-vivo bone mineral density (BMD) and quantitative trabecular assessment.Institutional review board approval was obtained. Twelve subjects with osteoporotic vertebral fractures 12 age- gender-matched controls undergoing routine thoracic abdominal MDCT were included (average effective dose: 10 mSv). Ultra-low examinations...
To assess whether phantomless calcium-hydroxyapatite (HA) specific bone mineral density (BMD) measurements with dual-layer spectral computed tomography are accurate in phantoms and vertebral specimens. Ex-vivo human vertebrae (n = 13) a phantom containing different known HA concentrations were placed semi-anthropomorphic abdomen extension rings simulating degrees of obesity. Phantomless CT was performed at tube current settings (500, 250, 125 50 mAs). HA-specific BMD derived from...
X-ray and particle radiation therapy planning requires accurate estimation of local electron density within the patient body to calculate dose delivery tumour regions. We evaluate feasibility accuracy measurement using dual-layer computed tomography (DLCT), a recently introduced dual-energy CT technique.Two calibration phantoms were scanned with DLCT virtual monoenergetic images (VMIs) at 50 keV 200 generated. investigated two approaches obtain relative densities from these VMIs: fit an...
Abstract Multidetector computed tomography–based trabecular bone microstructure analysis ensures promising results in fracture risk prediction caused by osteoporosis. Because multidetector tomography is associated with high radiation exposure, its clinical routine use limited. Hence, this study, we investigated 11 thoracic midvertebral specimens whether texture parameters are comparable derived from (1) images reconstructed using statistical iterative reconstruction (SIR) and filtered back...
To assess whether bone marrow edema in patients with acute vertebral fractures can be accurately diagnosed based on three-material decomposition dual-layer spectral CT (DLCT). Acute (n = 41) and chronic 18) osteoporotic thoracolumbar as by MRI (hyperintense signal STIR sequences) 27 subjects (72 ± 11 years; 17 women) were assessed DLCT. Spectral data decomposed into hydroxyapatite, edema-equivalent, fat-equivalent density maps using an in-house-developed algorithm. Two radiologists, blinded...
Abstract Purpose : To evaluate the benefit of additional available information present in spectral CT datasets, as compared to conventional when utilizing convolutional neural networks for fully automatic localisation and classification liver lesions images. Materials Methods Conventional images (iodine maps, virtual monochromatic (VMI)) were obtained from a dual-layer system. Patient diagnosis known clinical reports classified into healthy, cyst hypodense metastasis. In order compare value...
Purpose The purpose of this study was the evaluation anthropomorphic model observers trained with neural networks for prediction a human observer's performance. Methods To simulate liver lesions, phantom contrast targets (acrylic spheres, varying diameters, +30 HU ) repeatedly scanned on computed tomography scanner. Image data labeled confidence ratings assessed in reader detection task lesions were used to build several observers. Models images reconstructed iterative reconstruction and...
Abstract This study aimed to evaluate the effect of dose reduction, by means tube exposure on bone strength prediction from finite-element (FE) analysis. Fresh thoracic mid-vertebrae specimens (n = 11) were imaged, using multi-detector computed tomography (MDCT), at different intensities X-ray exposures (80, 150, 220 and 500 mAs). Bone mineral density (BMD) was estimated mid-slice each specimen MDCT images. Differences in image quality geometry measured. FE analysis performed all predict...
To systematically evaluate the effects of virtual tube current reduction and sparse sampling on image quality vertebral fracture diagnostics in multi-detector computed tomography (MDCT). In routine MDCT scans 35 patients (80.0% females, 70.6 ± 14.2 years, 65.7% showing fractures), reduced radiation doses were retrospectively simulated by virtually lowering currents applying sampling, considering 50%, 25%, 10% original projections, respectively. Two readers evaluated items presence fractures....
To compare CT pulmonary angiographies (CTPAs) as well phantom scans obtained at 100 kVp with a conventional (C-CT) to virtual monochromatic images (VMI) spectral detector (SD-CT) equivalent dose levels the radiation exposure of both systems. In total, 2110 patients suspected embolism (PE) were examined For each system (C-CT and SD-CT), imaging data 30 same mean index (4.85 mGy) was used for reader study. C-CT performed SD-CT 120 kVp; SD-CT, 40, 60 70 keV calculated. All datasets evaluated by...
To evaluate the diagnostic value of MR-derived CT-like images and simulated radiographs compared with conventional in patients suspected shoulder pathology.3 T MRI including a 3D T1-weighted gradient echo sequence was performed 25 (mean age 52.4 ± 18 years, 13 women) pathology. Subsequently cone-beam forward projection algorithm used to obtain intensity-inverted radiographs. Two radiologists evaluated separately independently using as standard reference, measurements image quality,...
Purpose: Reconstruction of x‐ray computed tomography (CT) data remains a mathematically challenging problem in medical imaging. Complementing the standard analytical reconstruction methods, sparse regularization is growing importance, as it allows inclusion prior knowledge. The paper presents method for based on curvelet frame application to iterative tomography. Methods: In this work, authors present an approach alternating direction multipliers using regularization. Results: Evaluation...
This study investigates the impact of tube current reduction and sparse sampling on femoral bone mineral density (BMD) measurements derived from multi-detector computed tomography (MDCT). The application led to robust clinically acceptable BMD measurements. In contrast, MDCT with virtually reduced currents showed a considerable increase when compared original data. aims evaluate effects radiation dose by using virtual or combined standard filtered back projection (FBP) statistical iterative...