@phdthesis{Portmann2023, author = {Portmann, Johannes}, title = {Accelerated inversion recovery MRI of the myocardium using spiral acquisition}, doi = {10.25972/OPUS-30282}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-302822}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {This work deals with the acceleration of cardiovascular MRI for the assessment of functional information in steady-state contrast and for viability assessment during the inversion recovery of the magnetization. Two approaches are introduced and discussed in detail. MOCO-MAP uses an exponential model to recover dynamic image data, IR-CRISPI, with its low-rank plus sparse reconstruction, is related to compressed sensing. MOCO-MAP is a successor to model-based acceleration of parametermapping (MAP) for the application in the myocardial region. To this end, it was augmented with a motion correction (MOCO) step to allow exponential fitting the signal of a still object in temporal direction. Iteratively, this introduction of prior physical knowledge together with the enforcement of consistency with the measured data can be used to reconstruct an image series from distinctly shorter sampling time than the standard exam (< 3 s opposed to about 10 s). Results show feasibility of the method as well as detectability of delayed enhancement in the myocardium, but also significant discrepancies when imaging cardiac function and artifacts caused already by minor inaccuracy of the motion correction. IR-CRISPI was developed from CRISPI, which is a real-time protocol specifically designed for functional evaluation of image data in steady-state contrast. With a reconstruction based on the separate calculation of low-rank and sparse part, it employs a softer constraint than the strict exponential model, which was possible due to sufficient temporal sampling density via spiral acquisition. The low-rank plus sparse reconstruction is fit for the use on dynamic and on inversion recovery data. Thus, motion correction is rendered unnecessary with it. IR-CRISPI was equipped with noise suppression via spatial wavelet filtering. A study comprising 10 patients with cardiac disease show medical applicability. A comparison with performed traditional reference exams offer insight into diagnostic benefits. Especially regarding patients with difficulty to hold their breath, the real-time manner of the IR-CRISPI acquisition provides a valuable alternative and an increase in robustness. In conclusion, especially with IR-CRISPI in free breathing, a major acceleration of the cardiovascular MR exam could be realized. In an acquisition of less than 100 s, it not only includes the information of two traditional protocols (cine and LGE), which take up more than 9.6 min, but also allows adjustment of TI in retrospect and yields lower artifact level with similar image quality.}, subject = {Kernspintomografie}, language = {en} } @article{ConradsGrunzHuflageetal.2023, author = {Conrads, Nora and Grunz, Jan-Peter and Huflage, Henner and Luetkens, Karsten Sebastian and Feldle, Philipp and Grunz, Katharina and K{\"o}hler, Stefan and Westermaier, Thomas}, title = {Accuracy of pedicle screw placement using neuronavigation based on intraoperative 3D rotational fluoroscopy in the thoracic and lumbar spine}, series = {Archives of Orthopaedic and Trauma Surgery}, volume = {143}, journal = {Archives of Orthopaedic and Trauma Surgery}, number = {6}, doi = {10.1007/s00402-022-04514-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324966}, pages = {3007-3013}, year = {2023}, abstract = {Introduction In spinal surgery, precise instrumentation is essential. This study aims to evaluate the accuracy of navigated, O-arm-controlled screw positioning in thoracic and lumbar spine instabilities. Materials and methods Posterior instrumentation procedures between 2010 and 2015 were retrospectively analyzed. Pedicle screws were placed using 3D rotational fluoroscopy and neuronavigation. Accuracy of screw placement was assessed using a 6-grade scoring system. In addition, screw length was analyzed in relation to the vertebral body diameter. Intra- and postoperative revision rates were recorded. Results Thoracic and lumbar spine surgery was performed in 285 patients. Of 1704 pedicle screws, 1621 (95.1\%) showed excellent positioning in 3D rotational fluoroscopy imaging. The lateral rim of either pedicle or vertebral body was protruded in 25 (1.5\%) and 28 screws (1.6\%), while the midline of the vertebral body was crossed in 8 screws (0.5\%). Furthermore, 11 screws each (0.6\%) fulfilled the criteria of full lateral and medial displacement. The median relative screw length was 92.6\%. Intraoperative revision resulted in excellent positioning in 58 of 71 screws. Follow-up surgery due to missed primary malposition had to be performed for two screws in the same patient. Postsurgical symptom relief was reported in 82.1\% of patients, whereas neurological deterioration occurred in 8.9\% of cases with neurological follow-up. Conclusions Combination of neuronavigation and 3D rotational fluoroscopy control ensures excellent accuracy in pedicle screw positioning. As misplaced screws can be detected reliably and revised intraoperatively, repeated surgery for screw malposition is rarely required.}, language = {en} } @article{WoznickiLaquaAlHajetal.2023, author = {Woznicki, Piotr and Laqua, Fabian Christopher and Al-Haj, Adam and Bley, Thorsten and Baeßler, Bettina}, title = {Addressing challenges in radiomics research: systematic review and repository of open-access cancer imaging datasets}, series = {Insights into Imaging}, volume = {14}, journal = {Insights into Imaging}, issn = {1869-4101}, doi = {10.1186/s13244-023-01556-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357936}, year = {2023}, abstract = {Objectives Open-access cancer imaging datasets have become integral for evaluating novel AI approaches in radiology. However, their use in quantitative analysis with radiomics features presents unique challenges, such as incomplete documentation, low visibility, non-uniform data formats, data inhomogeneity, and complex preprocessing. These issues may cause problems with reproducibility and standardization in radiomics studies. Methods We systematically reviewed imaging datasets with public copyright licenses, published up to March 2023 across four large online cancer imaging archives. We included only datasets with tomographic images (CT, MRI, or PET), segmentations, and clinical annotations, specifically identifying those suitable for radiomics research. Reproducible preprocessing and feature extraction were performed for each dataset to enable their easy reuse. Results We discovered 29 datasets with corresponding segmentations and labels in the form of health outcomes, tumor pathology, staging, imaging-based scores, genetic markers, or repeated imaging. We compiled a repository encompassing 10,354 patients and 49,515 scans. Of the 29 datasets, 15 were licensed under Creative Commons licenses, allowing both non-commercial and commercial usage and redistribution, while others featured custom or restricted licenses. Studies spanned from the early 1990s to 2021, with the majority concluding after 2013. Seven different formats were used for the imaging data. Preprocessing and feature extraction were successfully performed for each dataset. Conclusion RadiomicsHub is a comprehensive public repository with radiomics features derived from a systematic review of public cancer imaging datasets. By converting all datasets to a standardized format and ensuring reproducible and traceable processing, RadiomicsHub addresses key reproducibility and standardization challenges in radiomics. Critical relevance statement This study critically addresses the challenges associated with locating, preprocessing, and extracting quantitative features from open-access datasets, to facilitate more robust and reliable evaluations of radiomics models. Key points - Through a systematic review, we identified 29 cancer imaging datasets suitable for radiomics research. - A public repository with collection overview and radiomics features, encompassing 10,354 patients and 49,515 scans, was compiled. - Most datasets can be shared, used, and built upon freely under a Creative Commons license. - All 29 identified datasets have been converted into a common format to enable reproducible radiomics feature extraction.}, language = {en} } @phdthesis{Heuer2023, author = {Heuer, Anjana}, title = {Aktive Gefäßverschlusssysteme in der interventionellen Radiologie: Sicherheit und Effektivität des neuartigen Doppelclip-basierten Celt ACD® Systems}, doi = {10.25972/OPUS-30098}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300986}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Mit steigender Nachfrage an minimal-invasiven Therapieoptionen w{\"a}chst auch das Interesse an innovativen Alternativen im Bereich des arteriellen Gef{\"a}ßverschlusses nach PVI. Ziel der vorliegenden Arbeit war es, die Effektivit{\"a}t und Sicherheit eines neu auf dem Markt befindlichen, Doppelclip-basierten aktiven VVS zu pr{\"u}fen. Eine hohe technische Erfolgsrate von 98,8 \% bei einer geringen Komplikationsrate von 3,6 \% wurde verzeichnet. Bei Anwesenheit der Komorbidit{\"a}ten Dm und CNI 5 zeigte sich eine signifikante Assoziation zu einem vermehrten Auftreten von Komplikationen. Ein nachgewiesener signifikanter Zusammenhang bestand zudem zwischen einem erh{\"o}hten Kalzifikationsgrad der Punktionsstelle bei Vorliegen einer pAVK und eines Dm. Eine erh{\"o}hte Gef{\"a}ßrigidit{\"a}t aufgrund von Komorbidit{\"a}ten und vaskul{\"a}ren Kalzifikationen, intrinsische Fremdk{\"o}rperreaktionen, vasoregulatorische Reaktionen oder Produktversagen bieten hypothetische Erkl{\"a}rungsans{\"a}tze f{\"u}r die einzelnen komplikativen F{\"a}lle. Die Nutzung des VVS in spezifischen, bisher nicht beschriebenen Situationen (Unterdimensionierung, Anwendung nach Gef{\"a}ßpunktionen mit Zugangsschleusen bis 9F, antegrade Punktionsrichtung, anspruchsvolle Eingriffe multimorbider Patienten mit komplexem vaskul{\"a}rem Status) erwies sich als suffizient. Zur Pr{\"a}vention schwerwiegender Komplikationen w{\"a}hrend zuk{\"u}nftiger Interventionen wurden die Empfehlung ausgesprochen, eine Durchleuchtungsaufnahme zur Lagekontrolle vor Implantation des proximalen Clips anzufertigen. Eine speziell f{\"u}r Gef{\"a}ßverschl{\"u}sse nach antegrader Punktion konzipierte Zugangsschleuse k{\"o}nnte das Abknicken von Zugangsschleusen bei VVS Applikation verhindern. Zusammenfassend kann das untersuchte aktive VVS mit einzigartigem Wirkmechanismus und spezifischen Design als effektiv und sicher angesehen werden.}, subject = {Gef{\"a}ßverschluss}, language = {de} } @article{HennesHuflageGrunzetal.2023, author = {Hennes, Jan-Lucca and Huflage, Henner and Grunz, Jan-Peter and Hartung, Viktor and Augustin, Anne Marie and Patzer, Theresa Sophie and Pannenbecker, Pauline and Petritsch, Bernhard and Bley, Thorsten Alexander and Gruschwitz, Philipp}, title = {An intra-individual comparison of low-keV photon-counting CT versus energy-integrating-detector CT angiography of the aorta}, series = {Diagnostics}, volume = {13}, journal = {Diagnostics}, number = {24}, issn = {2075-4418}, doi = {10.3390/diagnostics13243645}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-355568}, year = {2023}, abstract = {This retrospective study aims to provide an intra-individual comparison of aortic CT angiographies (CTAs) using first-generation photon-counting-detector CT (PCD-CT) and third-generation energy-integrating-detector CT (EID-CT). High-pitch CTAs were performed with both scanners and equal contrast-agent protocols. EID-CT employed automatic tube voltage selection (90/100 kVp) with reference tube current of 434/350 mAs, whereas multi-energy PCD-CT scans were generated with fixed tube voltage (120 kVp), image quality level of 64, and reconstructed as 55 keV monoenergetic images. For image quality assessment, contrast-to-noise ratios (CNRs) were calculated, and subjective evaluation (overall quality, luminal contrast, vessel sharpness, blooming, and beam hardening) was performed independently by three radiologists. Fifty-seven patients (12 women, 45 men) were included with a median interval between examinations of 12.7 months (interquartile range 11.1 months). Using manufacturer-recommended scan protocols resulted in a substantially lower radiation dose in PCD-CT (size-specific dose estimate: 4.88 ± 0.48 versus 6.28 ± 0.50 mGy, p < 0.001), while CNR was approximately 50\% higher (41.11 ± 8.68 versus 27.05 ± 6.73, p < 0.001). Overall image quality and luminal contrast were deemed superior in PCD-CT (p < 0.001). Notably, EID-CT allowed for comparable vessel sharpness (p = 0.439) and less pronounced blooming and beam hardening (p < 0.001). Inter-rater agreement was good to excellent (0.58-0.87). Concluding, aortic PCD-CTAs facilitate increased image quality with significantly lower radiation dose compared to EID-CTAs}, language = {en} } @article{GrunzKunzBaumannetal.2023, author = {Grunz, Jan-Peter and Kunz, Andreas Steven and Baumann, Freerk T. and Hasenclever, Dirk and Sieren, Malte Maria and Heldmann, Stefan and Bley, Thorsten Alexander and Einsele, Hermann and Knop, Stefan and Jundt, Franziska}, title = {Assessing osteolytic lesion size on sequential CT scans is a reliable study endpoint for bone remineralization in newly diagnosed multiple myeloma}, series = {Cancers}, volume = {15}, journal = {Cancers}, number = {15}, issn = {2072-6694}, doi = {10.3390/cancers15154008}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-362526}, year = {2023}, abstract = {Multiple myeloma (MM) frequently induces persisting osteolytic manifestations despite hematologic treatment response. This study aimed to establish a biometrically valid study endpoint for bone remineralization through quantitative and qualitative analyses in sequential CT scans. Twenty patients (seven women, 58 ± 8 years) with newly diagnosed MM received standardized induction therapy comprising the anti-SLAMF7 antibody elotuzumab, carfilzomib, lenalidomide, and dexamethasone (E-KRd). All patients underwent whole-body low-dose CT scans before and after six cycles of E-KRd. Two radiologists independently recorded osteolytic lesion sizes, as well as the presence of cortical destruction, pathologic fractures, rim and trabecular sclerosis. Bland-Altman analyses and Krippendorff's α were employed to assess inter-reader reliability, which was high for lesion size measurement (standard error 1.2 mm) and all qualitative criteria assessed (α ≥ 0.74). After six cycles of E-KRd induction, osteolytic lesion size decreased by 22\% (p \< 0.001). While lesion size response did not correlate with the initial lesion size at baseline imaging (Pearson's r = 0.144), logistic regression analysis revealed that the majority of responding osteolyses exhibited trabecular sclerosis (p \< 0.001). The sum of osteolytic lesion sizes on sequential CT scans defines a reliable study endpoint to characterize bone remineralization. Patient level response is strongly associated with the presence of trabecular sclerosis.}, language = {en} } @phdthesis{KlinnertVlachopoulou2023, author = {Klinnert Vlachopoulou, Cristina Maria}, title = {Comparison between Dual-Energy-CT perfusion imaging and perfusion-weighted SElf-gated Non-Contrast-Enhanced FUnctional MR imaging of the lung in patients with pulmonary artery embolism}, doi = {10.25972/OPUS-31303}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313034}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Pulmonary artery embolism (PE) is a common condition and an even more common clinical suspect. The computed tomography pulmonary angiogram (CTPA) is the main medical imaging tool used to diagnose a suspected case of PE. To gain a better impression of the effects of a PE on the perfusion and hence the gas exchange, a functional imaging method is beneficial. One approach for functional imaging using radiation exposure is the generation of color-coded iodine perfusion maps acquired by Dual-Energy Computed Tomography (DECT), which enable the detection of perfusion defects in the pulmonary parenchyma. In contrast to the existing approach of DECT with iodine color-coded maps, the SElf-gated Non-Contrast-Enhanced FUnctional Lung (SENCEFUL) MRI technique offers the possibility to interpret perfusion maps without any radiation exposure or application of contrast agents. The measurement in SENCEFUL MRI can be performed during conditions of free breathing and without electrocardiogram triggering. The purpose of this study was to determine whether PE can be diagnosed on the basis of visible perfusion defects in the perfusion maps of SENCEFUL MRI and in the iodine-coded maps of DECT and to compare the diagnostic performance of these methods. Both SENCEFUL-MRI and iodine distribution maps from DECT have been compared with the CTPA of ten patients with PE. Additionally, the functional images were compared with each other on a per-patient basis. The iodine perfusion maps of DECT had a sensitivity of 84.2 \% and specificity of 65.2 \% for the diagnosis of PE. The SENCEFUL technique in MRI showed a sensitivity of 78.9 \% and a specificity of 26.1 \%. When comparing the whole lung depicted in both series of functional images, the main perfusion defect location matched in four of ten patients (40 \%). In conclusion, this work found that DECT iodine maps have higher sensitivity and specificity in the diagnosis of pulmonary embolism compared with SENCEFUL MRI.}, subject = {Lungenembolie}, language = {en} } @article{GruschwitzHartungErguenetal.2023, author = {Gruschwitz, Philipp and Hartung, Viktor and Erg{\"u}n, S{\"u}leyman and Peter, Dominik and Lichthardt, Sven and Huflage, Henner and Hendel, Robin and Pannenbecker, Pauline and Augustin, Anne Marie and Kunz, Andreas Steven and Feldle, Philipp and Bley, Thorsten Alexander and Grunz, Jan-Peter}, title = {Comparison of ultrahigh and standard resolution photon-counting CT angiography of the femoral arteries in a continuously perfused in vitro model}, series = {European Radiology Experimental}, volume = {7}, journal = {European Radiology Experimental}, doi = {10.1186/s41747-023-00398-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357905}, year = {2023}, abstract = {Background With the emergence of photon-counting CT, ultrahigh-resolution (UHR) imaging can be performed without dose penalty. This study aims to directly compare the image quality of UHR and standard resolution (SR) scan mode in femoral artery angiographies. Methods After establishing continuous extracorporeal perfusion in four fresh-frozen cadaveric specimens, photon-counting CT angiographies were performed with a radiation dose of 5 mGy and tube voltage of 120 kV in both SR and UHR mode. Images were reconstructed with dedicated convolution kernels (soft: Body-vascular (Bv)48; sharp: Bv60; ultrasharp: Bv76). Six radiologists evaluated the image quality by means of a pairwise forced-choice comparison tool. Kendall's concordance coefficient (W) was calculated to quantify interrater agreement. Image quality was further assessed by measuring intraluminal attenuation and image noise as well as by calculating signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR). Results UHR yielded lower noise than SR for identical reconstructions with kernels ≥ Bv60 (p < 0.001). UHR scans exhibited lower intraluminal attenuation compared to SR (Bv60: 406.4 ± 25.1 versus 418.1 ± 30.1 HU; p < 0.001). Irrespective of scan mode, SNR and CNR decreased while noise increased with sharper kernels but UHR scans were objectively superior to SR nonetheless (Bv60: SNR 25.9 ± 6.4 versus 20.9 ± 5.3; CNR 22.7 ± 5.8 versus 18.4 ± 4.8; p < 0.001). Notably, UHR scans were preferred in subjective assessment when images were reconstructed with the ultrasharp Bv76 kernel, whereas SR was rated superior for Bv60. Interrater agreement was high (W = 0.935). Conclusions Combinations of UHR scan mode and ultrasharp convolution kernel are able to exploit the full image quality potential in photon-counting CT angiography of the femoral arteries. Relevance statement The UHR scan mode offers improved image quality and may increase diagnostic accuracy in CT angiography of the peripheral arterial runoff when optimized reconstruction parameters are chosen. Key points • UHR photon-counting CT improves image quality in combination with ultrasharp convolution kernels. • UHR datasets display lower image noise compared with identically reconstructed standard resolution scans. • Scans in UHR mode show decreased intraluminal attenuation compared with standard resolution imaging.}, language = {en} } @article{GruschwitzHartungKleefeldtetal.2023, author = {Gruschwitz, Philipp and Hartung, Viktor and Kleefeldt, Florian and Peter, Dominik and Lichthardt, Sven and Huflage, Henner and Grunz, Jan-Peter and Augustin, Anne Marie and Erg{\"u}n, S{\"u}leyman and Bley, Thorsten Alexander and Petritsch, Bernhard}, title = {Continuous extracorporeal femoral perfusion model for intravascular ultrasound, computed tomography and digital subtraction angiography}, series = {PLoS One}, volume = {18}, journal = {PLoS One}, number = {5}, issn = {1932-6203}, doi = {10.1371/journal.pone.0285810}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350136}, year = {2023}, abstract = {Objectives We developed a novel human cadaveric perfusion model with continuous extracorporeal femoral perfusion suitable for performing intra-individual comparison studies, training of interventional procedures and preclinical testing of endovascular devices. Objective of this study was to introduce the techniques and evaluate the feasibility for realistic computed tomography angiography (CTA), digital subtraction angiography (DSA) including vascular interventions, and intravascular ultrasound (IVUS). Methods The establishment of the extracorporeal perfusion was attempted using one formalin-fixed and five fresh-frozen human cadavers. In all specimens, the common femoral and popliteal arteries were prepared, introducer sheaths inserted, and perfusion established by a peristaltic pump. Subsequently, we performed CTA and bilateral DSA in five cadavers and IVUS on both legs of four donors. Examination time without unintentional interruption was measured both with and without non-contrast planning CT. Percutaneous transluminal angioplasty and stenting was performed by two interventional radiologists on nine extremities (five donors) using a broad spectrum of different intravascular devices. Results The perfusion of the upper leg arteries was successfully established in all fresh-frozen but not in the formalin-fixed cadaver. The experimental setup generated a stable circulation in each procedure (ten upper legs) for a period of more than six hours. Images acquired with CT, DSA and IVUS offered a realistic impression and enabled the sufficient visualization of all examined vessel segments. Arterial cannulating, percutaneous transluminal angioplasty as well as stent deployment were feasible in a way that is comparable to a vascular intervention in vivo. The perfusion model allowed for introduction and testing of previously not used devices. Conclusions The continuous femoral perfusion model can be established with moderate effort, works stable, and is utilizable for medical imaging of the peripheral arterial system using CTA, DSA and IVUS. Therefore, it appears suitable for research studies, developing skills in interventional procedures and testing of new or unfamiliar vascular devices.}, language = {en} } @article{EwaldFuchsBoegeleinetal.2023, author = {Ewald, Andrea and Fuchs, Andreas and Boegelein, Lasse and Grunz, Jan-Peter and Kneist, Karl and Gbureck, Uwe and Hoelscher-Doht, Stefanie}, title = {Degradation and bone-contact biocompatibility of two drillable magnesium phosphate bone cements in an in vivo rabbit bone defect model}, series = {Materials}, volume = {16}, journal = {Materials}, number = {13}, issn = {1996-1944}, doi = {10.3390/ma16134650}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-362824}, year = {2023}, abstract = {The use of bone-cement-enforced osteosynthesis is a growing topic in trauma surgery. In this context, drillability is a desirable feature for cements that can improve fracture stability, which most of the available cement systems lack. Therefore, in this study, we evaluated a resorbable and drillable magnesium-phosphate (MgP)-based cement paste considering degradation behavior and biocompatibility in vivo. Two different magnesium-phosphate-based cement (MPC) pastes with different amounts of phytic acid (IP 6) as setting retarder (MPC 22.5 and MPC 25) were implanted in an orthotopic defect model of the lateral femoral condyle of New Zealand white rabbits for 6 weeks. After explantation, their resorption behavior and material characteristics were evaluated by means of X-ray diffraction (XRD), porosimetry measurement, histological staining, peripheral quantitative computed tomography (pQCT), cone-beam computed tomography (CBCT) and biomechanical load-to-failure tests. Both cement pastes displayed comparable results in mechanical strength and resorption kinetics. Bone-contact biocompatibility was excellent without any signs of inflammation. Initial resorption and bone remodeling could be observed. MPC pastes with IP 6 as setting retardant have the potential to be a valuable alternative in distinct fracture patterns. Drillability, promising resorption potential and high mechanical strength confirm their suitability for use in clinical routine.}, language = {en} }