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Minimally invasive endovascular interventions have become an important tool for the treatment of cardiovascular diseases such as ischemic heart disease, peripheral artery disease, and stroke. X-ray fluoroscopy and digital subtraction angiography are used to precisely guide these procedures, but they are associated with radiation exposure for patients and clinical staff. Magnetic Particle Imaging (MPI) is an emerging imaging technology using time-varying magnetic fields combined with magnetic nanoparticle tracers for fast and highly sensitive imaging. In recent years, basic experiments have shown that MPI has great potential for cardiovascular applications. However, current MPI scanners were too large, slow and expensive, and had a very small field of view (FOV), which limited further translational research. Here, we present a portable interventional MPI (iMPI) scanner dedicated for real-time endovascular interventions free of ionizing radiation. It uses a novel field generator approach with a very large FOV and an application-oriented open design enabling hybrid approaches with conventional X-ray-based angiography. The feasibility of a real-time iMPI-guided percutaneous transluminal angioplasty (PTA) is shown in a realistic dynamic human-sized leg model.

Measurement of minimal residual disease (MRD) by next-generation flow cytometry (NGF) is an important tool to define deep responses in multiple myeloma (MM). However, little is known about the value of combining NGF with functional imaging and its role for MRD-based consolidation strategies in clinical routine. In the present study, we report our experience investigating these issues with 102 patients with newly diagnosed (n = 57) and relapsed/refractory MM (n = 45). Imaging was performed using either positron emission tomography or diffusion-weighted magnetic resonance imaging. In all, 45% of patients achieved MRD-negativity on both NGF and imaging (double-negativity), and 8% and 40% of patients were negative on either NGF or imaging respectively. Thus, in a minority of patients imaging was the only technique to detect residual disease. Imaging-positivity despite negativity on NGF was more common in heavily pretreated disease (four or more previous lines) compared to newly diagnosed MM (p 0.01). Among the 29 patients undergoing MRD-triggered consolidation, 51% responded with MRD conversion and 21% with improved serological response. MRD-triggered consolidation led to superior progression-free survival (PFS) when compared to standard treatment (p = 0.04). In conclusion, we show that combining NGF with imaging is helpful particularly in patients with heavily pretreated MM, and that MRD-based consolidation could lead to improved PFS.

PURPOSE: The gradient system transfer function (GSTF) can be used to describe the dynamic gradient system and applied for trajectory correction in non-Cartesian MRI. This study compares the field camera and the phantom-based methods to measure the GSTF and implements a compensation for the difference in measurement dwell time. METHODS: The self-term GSTFs of a MR system were determined with two approaches: 1) using a dynamic field camera and 2) using a spherical phantom-based measurement with standard MR hardware. The phantom-based GSTF was convolved with a box function to compensate for the dwell time dependence of the measurement. The field camera and phantom-based GSTFs were used for trajectory prediction during retrospective image reconstruction of 3D wave-CAIPI phantom images. RESULTS: Differences in the GSTF magnitude response were observed between the two measurement methods. For the wave-CAIPI sequence, this led to deviations in the GSTF predicted trajectories of 4% compared to measured trajectories, and residual distortions in the reconstructed phantom images generated with the phantom-based GSTF. Following dwell-time compensation, deviations in the GSTF magnitudes, GSTF-predicted trajectories, and resulting image artifacts were eliminated (< 0.5% deviation in trajectories). CONCLUSION: With dwell time compensation, both the field camera and the phantom-based GSTF self-terms show negligible deviations and lead to strong artifact reduction when they are used for trajectory correction in image reconstruction.

Objectives Vessel wall enhancement (VWE) may be commonly seen on MRI images of asymptomatic subjects. This study aimed to characterize the VWE of the proximal internal carotid (ICA) and vertebral arteries (VA) in a non-vasculitic elderly patient cohort. Methods Cranial MRI scans at 3 Tesla were performed in 43 patients (aged ≥ 50 years) with known malignancy for exclusion of cerebral metastases. For vessel wall imaging (VWI), a high-resolution compressed-sensing black-blood 3D T1-weighted fast (turbo) spin echo sequence (T1 CS-SPACE prototype) was applied post gadolinium with an isotropic resolution of 0.55 mm. Bilateral proximal intradural ICA and VA segments were evaluated for presence, morphology, and longitudinal extension of VWE. Results Concentric VWE of the proximal intradural ICA was found in 13 (30%) patients, and of the proximal intradural VA in 39 (91%) patients. Mean longitudinal extension of VWE after dural entry was 13 mm in the VA and 2 mm in the ICA. In 14 of 39 patients (36%) with proximal intradural VWE, morphology of VWE was suggestive of the mere presence of vasa vasorum. In 25 patients (64 %), morphology indicated atherosclerotic lesions in addition to vasa vasorum. Conclusions Vasa vasorum may account for concentric VWE within the proximal 2 mm of the ICA and 13 mm of the VA after dural entry in elderly subjects. Concentric VWE in these locations should not be confused with large artery vasculitis. Distal to these segments, VWE may be more likely related to pathologic conditions such as vasculitis. Key Points • Vasa vasorum may account for concentric VWE within the proximal 2 mm of the ICA and 13 mm of the VA after dural entry in non-vasculitic elderly people. • Concentric enhancement within the proximal 2 mm of the intradural ICA and within the proximal 13 mm of the intradural VA portions should not be misinterpreted as vasculitis. • Distal of this, VWE is likely related to pathologic conditions, in case of concentric VWE suggestive of vasculitis.

No abstract available.

Purpose: We evaluate the performance of a deep learning-based pipeline using a Dense U-net architecture for detection of intracranial hemorrhage (ICH) in unenhanced head computed tomography (CT) scans. Methods: A balanced database was assembled retrospectively, comprising a total of 872 CT scans (362 with present ICH). Predictions by the algorithm were analyzed and compared to the radiology report (ground truth). Secondly, the algorithm's performance was tested in clinical environment: A total of 100 head CT scans (11 with present ICH) were analyzed simultaneously by the deep learning algorithm and a radiologist during clinical routine. The time until first temporary diagnosis of ICH was measured. Performances of the algorithm were evaluated in combination with the radiologist, when using it as triage tool. Results: In the retrospectively assembled dataset the deep learning algorithm detected ICH with a sensitivity of 91.4%, specificity of 90.4% and overall accuracy of 91.0%. In clinical environment, the algorithm was significantly faster compared to the temporary report of the assigned radiologist (24 ± 2 s vs. 613 ± 658 s, p < 0.001). When using the algorithm as a triage tool additional to the report of the assigned radiologist, a sensitivity of 100% was achieved. Conclusions: These results and the short processing time demonstrate the immense potential of deep learning applications for the use as triage tool and for additional review of manual reports.

In Giant Cell Arteritis (GCA), a timely diagnosis is required to avoid severe complications such as blindness or structural vascular damage. The heterogeneous symptoms are mainly due to local and systemic inflammatory processes. Diagnostics are based on increased inflammation parameters in the laboratory, imaging, in which color-coded duplex sonography (FKDS), high-resolution magnetic resonance imaging (MRI), computer tomography (CT) or CT angiography (CTA) and 18F fluorodeoxyglucose-positron emission tomography with CT (FDG-PET-CT) have become established, as well as histopathological findings in temporal artery biopsy.

Bildgebende Verfahren sind neben der korperlichen und laborchemischen Untersuchung wesentliche Bestandteile der Diagnostik und des Monitorings vieler entzundlicher Gefaserkrankungen, wobei diesen sowohl zur Erfassung der Krankheitsausdehnung als auch der Krankheitsaktivitat eine entscheidende Bedeutung zukommt. Vaskulitische Gefasveranderungen konnen schwerwiegende Folgen nach sich ziehen – verlassliche Resultate in der Diagnostik und zur Beurteilung des Therapieansprechens sind daher essenziell. Die heutzutage gangigen Methoden, Moglichkeiten und Standards bildgebender Verfahren sowie typische Bildbefunde bei verschiedenen entzundlichen Gefaserkrankungen, insbesondere den Grosgefasvaskulitiden und der primaren Zentralnervensystem(ZNS)-Vaskulitis, sollen aufgezeigt werden. Mit verschiedenen Modalitaten, insbesondere der Sonographie/farbkodierten Dopplersonographie (FKDS), der Magnetresonanztomographie (MRT), Magnetresonanzangiographie (MRA), der Computertomographie (CT), der CT-Angiographie, der Positronenemissionstomographie (PET) und der Angiographie bzw. der digitalen Subtraktionsangiographie (DSA) stehen zahlreiche bildgebende Verfahren zur Verfugung, pathognomonische Befunde bzw. direkte und indirekte Krankheitszeichen der Vaskulitiden zu visualisieren. Angesichts der Vielzahl verschiedener Vaskulitiden, der Mannigfaltigkeit ihres klinischen und radiologischen Erscheinungsbildes sowie der zahlreichen hiervon abzugrenzenden Differenzialdiagnosen stellt die Bildgebung des Formenkreises vaskulitischer Erkrankungen haufig eine Herausforderung dar, nimmt aber gleichzeitig im interdisziplinaren Management eine zunehmend wichtige Rolle ein.

Key Points Question What is the diagnostic accuracy of 18-F fluorodeoxyglucose positron emission tomographic/computed tomographic imaging in squamous cell carcinoma of the oral cavity for detection of metastases? Findings This diagnostic study including 135 patients showed 83.3% sensitivity, 84.8% specificity, and a negative predictive value of 93.3% with use of 18-F fluorodeoxyglucose positron emission tomographic/computed tomographic imaging for detecting cervical lymph node metastases. The specificity was significantly higher than observed for use of cervical computed tomography and magnetic resonance imaging. Meaning Owing to its high negative predictive value, preoperative 18-F fluorodeoxyglucose positron emission tomographic/computed tomographic imaging may be useful to prevent overtreatment in more than 70% of patients with category T1 to T4 tumors of the oral cavity., Importance Squamous cell carcinoma (SCC) of the oral cavity is one of the most common tumor entities worldwide. Precise initial staging is necessary to determine a diagnosis, treatment, and prognosis. Objective To examine the diagnostic accuracy of preoperative 18-F fluorodeoxyglucose (FDG) positron emission tomographic/computed tomographic (PET/CT) imaging in detecting cervical lymph node metastases. Design, Setting, and Participants This prospective diagnostic study was performed at a single tertiary reference center between June 1, 2013, and January 31, 2016. Data were analyzed from April 7, 2018, through May 31, 2019. Observers of the FDG PET/CT imaging were blinded to patients’ tumor stage. A total of 150 treatment-naive patients with clinical suspicion of SCC of the oral cavity were enrolled. Exposures All patients underwent FDG PET/CT imaging before local tumor resection with selective or complete neck dissection. Main Outcomes and Measures The accuracy of FDG PET/CT in localizing primary tumor, lymph node, and distant metastases was tested. Histopathologic characteristics of the tissue samples served as the standard of reference. Results Of the 150 patients enrolled, 135 patients (74 [54.8%] men) with a median age of 63 years (range, 23-88 years) met the inclusion criteria (histopathologically confirmed primary SCC of the oral cavity/level-based histopathologic assessment of the resected lymph nodes). Thirty-six patients (26.7%) in the study cohort had neck metastases. Use of FDG PET/CT detected cervical lymph node metastasis with 83.3% sensitivity (95% CI, 71.2%-95.5%) and 84.8% specificity (95% CI, 77.8%-91.9%) and had a negative predictive value of 93.3% (95% CI, 88.2%-98.5%). The specificity was higher than for contrast-enhanced cervical CT imaging (67.0%; 95% CI, 57.4%-76.7%; P, This diagnostic study examines the accuracy of F-18 fluorodeoxyglucose positron emission tomographic/computed tomographic imaging for detection of primary tumor, lymph node, and distant metastases in patients with oral cavity squamous cell carcinoma.

Die FKDS erlaubt die Beurteilung der Anatomie, der Morphologie und der Hamodynamik von Gefasen. Die funktionelle Untersuchung kann durch die genaue Bestimmung der Untersuchungstiefe und der optimalen Platzierung der Probenentnahmestelle („sample volume“) bestimmten Gefasabschnitten zugeordnet werden. Durch die Kenntnis und optimale Einstellung des Beschallungswinkels konnen die Dopplerfrequenzen in Flussgeschwindigkeiten umgerechnet werden. Das folgende Kapitel soll nun die Anwendung der Methode durch die Beschreibung der Untersuchung einzelner Gefasprovinzen erlautern. Fur eine genauere Darstellung der physikalischen Grundlagen und der Anwendung verweisen wir auf die Vielzahl der Standardwerke zu diesem Thema.

Hinsichtlich der Genauigkeit und Ubersichtlichkeit der Darstellung gilt die intraarterielle digitale Subtraktionsangiographie (i.a. DSA) weiterhin als Goldstandard. Nach lokaler Betaubung wird unter sterilen Kautelen in der Regel die A. femoralis communis punktiert. Uber die Punktionsnadel wird dann ein Fuhrdraht in die Arterie eingefuhrt, uber den nun in Seldinger-Technik eine intraarterielle Schleuse eingebracht werden kann. Uber diesen Zugang kann das entsprechende Gefasterritorium mit den benotigten Fuhrdrahten und Kathetern aufgesucht und angiographiert werden. Fur die Angiographie der aorto-iliakalen Strombahn bzw. deren Aste wird in der Regel die A. femoralis communis retrograd punktiert. Dagegen kann bei geplanter perkutaner transarterieller Angioplastie (PTA) der Beinstrombahn initial eine antegrade Punktion der A. femoralis communis durchgefuhrt werden. Dieses Vorgehen bedingt in der Regel eine gute Fuhrbarkeit der Drahte und Katheter. Die Punktionsstelle der A. femoralis communis muss sorgfaltig ausgewahlt werden, um nicht versehentlich zu weit kaudal die A. femoralis profunda zu punktieren, von der aus ein weiteres Vorgehen in die Beinstrombahn unmoglich ist. Dagegen kann ein Cross-over-Vorgehen nach retrograder Punktion der kontralateralen A. femoralis communis und Passage uber die Aortenbifurkation auf die Gegenseite die Fuhrbarkeit der Katheter insbesondere bei ausgepragtem Kinking der Iliakalarterien erheblich erschweren.

Purpose of Review Vasculitides are characterized by mostly autoimmunologically induced inflammatory processes of vascular structures. They have various clinical and radiologic appearances. Early diagnosis and reliable monitoring are indispensable for adequate therapy to prevent potentially serious complications. Imaging, in addition to laboratory tests and physical examination, constitutes a key component in assessing disease extent and activity. This review presents current standards and some typical findings in the context of imaging in vasculitis with particular attention to large vessel vasculitides. Recent Findings Recently, imaging has gained importance in the management of vasculitis, especially regarding large vessel vasculitides (LVV). Recently, EULAR (European League Against Rheumatism) has launched its recommendations concerning the diagnosis of LVVs. Imaging is recommended as the preferred complement to clinical examination. Color-coded duplex sonography is considered the first choice imaging test in suspected giant cell arteritis, and magnetic resonance imaging is considered the first choice in suspected Takayasu’s arteritis. Summary Due to diversity of clinical and radiologic presentations, diagnosis and therapy monitoring of vasculitides may constitute a challenge. As a result of ongoing technological progress, a variety of non-invasive imaging modalities now play an elemental role in the interdisciplinary management of vasculitic diseases.

Importance Total neoadjuvant therapy has been increasingly adopted for multimodal rectal cancer treatment. The optimal sequence of chemoradiotherapy (CRT) and chemotherapy needs to be established. Objective To report the long-term results of the secondary end points prespecified in the Randomized Phase 2 Trial of Chemoradiotherapy Plus Induction or Consolidation Chemotherapy as Total Neoadjuvant Therapy (CAO/ARO/AIO-12 trial) for Locally Advanced Rectal Cancer. Design, Setting, and Participants This secondary analysis of a randomized clinical trial included 311 patients who were recruited from the accrued CAO/ARO/AIO-12 trial population from June 15, 2015, to January 31, 2018, from 18 centers in Germany. Patients with cT3-4 and/or node-positive rectal adenocarcinoma were included in the analysis. Data were analyzed from June 15, 2015, to January 31, 2018. The follow-up analysis was conducted between January 31, 2018, and November 30, 2020. Interventions Patients were randomly assigned to group A for 3 cycles of fluorouracil, leucovorin, and oxaliplatin before fluorouracil/oxaliplatin CRT (50.4 Gy), or to group B for CRT before chemotherapy. Total mesorectal excision was scheduled on day 123 after the start of total neoadjuvant therapy in both groups. Main Outcomes and Measures The end points assessed in this secondary analysis included long-term oncologic outcomes, chronic toxicity, patient-reported outcome measures for global health status (GHS) and quality of life (QoL), and the Wexner stool incontinence score. Results Of the 311 patients enrolled, 306 were evaluable, including 156 in group A (mean [SD] age, 60 [11] years; 106 men [68%]) and 150 in group B (mean [SD] age, 62 [10] years; 100 men [67%]). After a median follow-up of 43 months (range, 35-60 months), the 3-year disease-free survival was 73% in both groups (hazard ratio, 0.95; 95% CI, 0.63-1.45,P = .82); the 3-year cumulative incidence of locoregional recurrence (6% vs 5%,P = .67) and distant metastases (18% vs 16%,P = .52) were not significantly different. Chronic toxicity grade 3 to 4 occurred in 10 of 85 patients (11.8%) in group A and 8 of 66 patients (9.9%) in group B at 3 years. The GHS/QoL score decreased after total mesorectal excision but returned to pretreatment levels 1 year after randomization with no difference between the groups. Stool incontinence deteriorated 1 year after randomization in both groups and only improved slightly at 3 years, but never reached baseline levels. Conclusions and Relevance This secondary analysis of a randomized clinical trial showed that CRT followed by chemotherapy resulted in higher pathological complete response without compromising disease-free survival, toxicity, QoL, or stool incontinence and is thus proposed as the preferred total neoadjuvant therapy sequence if organ preservation is a priority. Trial Registration ClinicalTrials.gov identifier:NCT02363374

Our study proposes the use of a frequency-modulated acquisition which suppresses banding artefacts in combination with a phase-sensitive water-fat separation algorithm. The performance of the phase-sensitive separation for standard bSSFP, complex sum combination thereof, and frequency-modulated bSSFP were compared in in vivo measurements of the upper and lower legs at 1.5 and 3 T. It is shown, that the standard acquisition suffered from banding artefacts and major swaps between tissues. The dual-acquisition bSSFP could alleviate banding artefacts and only minor swaps occurred, but it comes at the expense of a doubled acquisition. In the frequency-modulated acquisitions all banding artefacts and the associated phase jumps were eliminated and no swaps between tissues occurred. It therefore provides a means to robustly separate water and fat, in one single radial bSSFP scan, using the phase-sensitive approach, even in the presence of high field inhomogeneities.

Echo Planar Imaging (EPI) is most commonly applied to acquire diffusion-weighted MR-images. EPI is able to capture an entire image in very short time, but is prone to distortions and artifacts . In diffusion-weighted EPI of the kidney severe distortions may occur due to intestinal gas. Turbo Spin Echo (TSE) is robust against distortions and artifacts, but needs more time to acquire an entire image compared to EPI. Therefore, TSE is more sensitive to motion during the readout. In this study we compare diffusion-weighted TSE and EPI of the human kidney with regard to intravoxel incoherent motion (IVIM) and diffusion tensor imaging (DTI). Images were acquired with b-values between 0 and 750 s/mm2 with TSE and EPI. Distortions were observed with the EPI readout in all volunteers, while the TSE images were virtually distortion-free. Fractional anisotropy of the diffusion tensor was significantly lower for TSE than for EPI. All other parameters of DTI and IVIM were comparable for TSE and EPI. Especially the main diffusion directions yielded by TSE and EPI were similar. The results demonstrate that TSE is a worthwhile distortion-free alternative to EPI for diffusion-weighted imaging of the kidney at 3 Tesla.

Purpose Banding artifacts in images acquired by balanced steady-state free precession (bSSFP) remain a challenge in MRI as they considerably reduce image quality, and diagnostic value deteriorates accordingly. As the steady-state tolerates small shifts in frequency, it is possible to acquire frequency-modulated bSSFP. Unfortunately, standard reconstructions of such measurements suffer from signal loss. Our study proposes a multifrequency reconstruction and demonstrates its capability of suppressing banding artifacts while retaining the high signal level of standard bSSFP. Methods Numerical simulations in vitro and in vivo measurements were performed using both standard bSSFP and frequency-modulated bSSFP. The modulated data were reconstructed using a multifrequency approach consisting of three steps: phase correction, multiple reconstructions for different assumed frequencies, and maximum intensity projection. Results Although standard bSSFP measurements showed banding artifacts that compromised the image quality, standard reconstructions of frequency-modulated acquisitions suffered from signal loss. In contrast, images reconstructed from frequency-modulated data using the proposed multifrequency reconstruction showed no visual bandings and featured a higher signal-to-noise ratio (SNR). The SNR gain for phantom and in vivo measurements ranged from 1.23 to 1.49. Conclusions The presented multifrequency reconstruction for frequency-modulated bSSFP provides images showing no bandings and featuring high SNR in short scan times. Magn Reson Med 78:2226–2235, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

In Giant Cell Arteritis (GCA), a timely diagnosis is required to avoid severe complications such as blindness or structural vascular damage. The heterogeneous symptoms are mainly due to local and systemic inflammatory processes. Diagnostics are based on increased inflammation parameters in the laboratory, imaging, in which color-coded duplex sonography (FKDS), high-resolution magnetic resonance imaging (MRI), computer tomography (CT) or CT angiography (CTA) and

BackgroundPercutaneous biliary drainage (PTBD) is a necessary procedure in several benign and malignant conditions. After PTBD removal biliocutaneous fistula is a rare but potential complication. D...

Aortic aneurysmal disease of the thoracic and abdominal aorta is a potentially life-threatening disease and requires besides preventive measures early detection of the disease and if present for the patient-tailored interventional treatment. This paper will discuss the current role of imaging in the assessment of pre- and post-aortic endovascular intervention tailored to treat aortic aneurysmal disease of the thoracic and abdominal aorta.

By combining intravoxel incoherent motion (IVIM) and diffusion tensor imaging (DTI) we introduce a new diffusion model called intravoxel oriented flow (IVOF) that accounts for anisotropy of diffusion and the flow-related signal. An IVOF model using a simplified apparent flow fraction tensor (IVOFf ) is applied to diffusion-weighted imaging of human kidneys. The kidneys of 13 healthy volunteers were examined on a 3 T scanner. Diffusion-weighted images were acquired with six b values between 0 and 800 s/mm(2) and 30 diffusion directions. Diffusivity and flow fraction were calculated for different diffusion models. The Akaike information criterion was used to compare the model fit of the proposed IVOFf model to IVIM and DTI. In the majority of voxels the proposed IVOFf model with a simplified apparent flow fraction tensor performs better than IVIM and DTI. Mean diffusivity is significantly higher in DTI compared with models that account for the flow-related signal. The fractional anisotropy of diffusion is significantly reduced when flow fraction is considered to be anisotropic. Anisotropy of the apparent flow fraction tensor is significantly higher in the renal medulla than in the cortex region. The IVOFf model describes diffusion-weighted data in the human kidney more accurately than IVIM or DTI. The apparent flow fraction in the kidney proved to be anisotropic.

Purpose This study aimed to develop a 3D MRI technique to assess lung ventilation in free-breathing and without the administration of contrast agent. Methods A 3D-UTE sequence with a koosh ball trajectory was developed for a 3 Tesla scanner. An oversampled k-space was acquired, and the direct current signal from the k-space center was used as a navigator to sort the acquired data into 8 individual breathing phases. Gradient delays were corrected, and iterative SENSE was used to reconstruct the individual timeframes. Subsequently, the signal changes caused by motion were eliminated using a 3D image registration technique, and ventilation-weighted maps were created by analyzing the signal changes in the lung tissue. Six healthy volunteers and 1 patient with lung cancer were scanned with the new 3D-UTE and the standard 2D technique. Image quality and quantitative ventilation values were compared between both methods. Results UTE-based self-gated noncontrast-enhanced functional lung (SENCEFUL) MRI provided a time-resolved reconstruction of the breathing motion, with a 49% increase of the SNR. Ventilation quantification for healthy subjects was in statistical agreement with 2D-SENCEFUL and the literature, with a mean value of 0.11 ± 0.08 mL/mL for the whole lung. UTE-SENCEFUL was able to visualize and quantify ventilation deficits in a patient with lung tumor that were not properly depicted by 2D-SENCEFUL. Conclusion UTE-SENCEFUL represents a robust MRI method to assess both morphological and functional information of the lungs in 3D. When compared to the 2D approach, 3D-UTE offered ventilation maps with higher resolution, improved SNR, and reduced ventilation artifacts.

Purpose: To evaluate the feasibility and efficacy of C-arm fluoroscopic cone-beam computed tomography (CACT) in combination with a new electromagnetic tracking (EMT) system for needle guidance during percutaneous biopsies. Materials and Methods: 53 patients were referred for biopsy of thoracic (n = 19) and abdominal (n = 34) lesions. CT-like images of the anatomical region of interest (ROI) were generated using a flat panel-based angiographic system. These images were transmitted to an EMT system. A coaxial puncture needle with a sensor in its tip was connected with the navigation system and tracked into an electromagnetic field created via a field generator. Data generated within this field were merged with the CACT images. On a monitor both the anatomical ROI and needle tip position were displayed to enable precise needle insertion into the target. Through the coaxial needle, biopsy specimens for the histologic evaluation were extracted. Number of representative biopsy samples, number of core biopsies/patient, total procedure time, dose-area product, fluoroscopic time, and complications were recorded. Results: 53 CACT/EMT-guided biopsy procedures were performed, 48 of which (91 %) yielded representative tissue samples. Four core biopsies were obtained from each patient. 40 (75 %) lesions were malignant and 13 (25 %) lesions were benign. The total procedure time was 9 ± 5 min (range, 3 – 23 min), fluoroscopic time was 0.8 ± 0.4 min (range, 0.4 – 2 min). The mean dose-area product (cGy cm²) was 7373 (range, 895 – 26 904). The rate of complications (1 pneumothorax, 2 hemoptyses) was 6 %. Conclusion: CACT combined with EMT appears to be a feasible and effective technique for the guidance of percutaneous biopsies with a low rate of therapeutically relevant complications. Key Points: • Guidance of percutaneous biopsies with a combination of CACT and EMT is technically feasible. • CACT/EMT-guided biopsies are associated with a good diagnostic yield. • The rate of complications appears to be low for this guidance technique. Citation Format: • Kickuth R., Reichling C., Bley T. et al. C-Arm Cone-Beam CT Combined with a New Electromagnetic Navigation System for Guidance of Percutaneous Needle Biopsies: Initial Clinical Experience. Fortschr Rontgenstr 2015; 187: 569 – 576

Neoadjuvant therapy could improve oncological outcome of patients suffering from colon cancer. An accurate staging method is needed to define suitable patients. The aim of this retrospective study was to validate the value of CT for identifying patients with local advanced (T3/4) or nodal-positive colon cancer. Preoperative abdominal CT scans of 210 patients with colon cancer were evaluated by two radiologists independently for the T stage and N stage. Results were compared to pathology. Patients were stratified according to the guidelines for rectal cancer into patients with low risk (T0/1/2 and N0) or high risk (T3/4 or N+). Inter-observer correlation was high with over 90 %. Overall sensitivity T stage was 93.0 % and for N stage 76.9 %. Using CT scan to identify local advanced (T3/4 or N+) tumors, the consensus sensitivity was 94.9 %, the specificity 53.6 %, the positive predictive value (PPV) 92.8 %, and the negative predictive value (NPV) 62.5 %. Computer tomography represents an effective tool for identifying patients with colon cancer suitable for neoadjuvant therapy according to the guidelines for rectal cancer.

Purpose To survey integrative teaching in radiology at German universities. Materials and methods A questionnaire about radiological education was sent electronically to all 37 chairpersons of university radiology departments in Germany. The questions included the course type, teaching methods, concept, perception, and advantages and disadvantages of integrative teaching. Statistical analysis was performed with nonparametric statistics and chi-square test. Results The survey was considered representative with a return rate of 68 %. Integrative teaching is established at 4/5 of all departments. Integrative teaching is well accepted with an acceptance rate that is significantly higher in so-called "Modellstudiengangen" [model courses of study] (100 %) compared to conventional courses of study (72 %). The advantages of integrative teaching include linking of content (92 %) and preparation for interdisciplinary work (76 %). The disadvantages include high effort (75 %) and time (67 %) for organization. Furthermore, there is a risk that basic radiological facts and knowledge cannot be conveyed and that the visibility of radiology as an independent discipline is lost. Conventional radiological teaching has a similarly high acceptance (84 %) compared to integrative courses (76 %). Conclusion Integrative teaching has a high acceptance among chairpersons in radiology in Germany despite the greater effort. A good interdisciplinary collaboration is essential for integrative teaching and at the same time this can be conveyed to the students. However, the visibility of radiology as a discipline and the possibility to cover basic radiological content must be ensured. Therefore, both conventional courses and integrative teaching seems reasonable, especially in cross-disciplinary subjects such as radiology. Key points Both integrative teaching and conventional radiological teaching are highly accepted. The advantages include the linking of multidisciplinary content and the preparation for interdisciplinary cooperation. The disadvantages include more time and effort for organization and reduced visibility of cross-disciplinary subjects.

Purpose The gradient system transfer function (GSTF) has been used to describe the distorted k-space trajectory for image reconstruction. The purpose of this work was to use the GSTF to determine the pre-emphasis for an undistorted gradient output and intended k-space trajectory. Methods The GSTF of the MR system was determined using only standard MR hardware without special equipment such as field probes or a field camera. The GSTF was used for trajectory prediction in image reconstruction and for a gradient waveform pre-emphasis. As test sequences, a gradient-echo sequence with phase-encoding gradient modulation and a gradient-echo sequence with a spiral read-out trajectory were implemented and subsequently applied on a structural phantom and in vivo head measurements. Results Image artifacts were successfully suppressed by applying the GSTF-based pre-emphasis. Equivalent results are achieved with images acquired using GSTF-based post-correction of the trajectory as a part of image reconstruction. In contrast, the pre-emphasis approach allows reconstruction using the initially intended trajectory. Conclusion The artifact suppression shown for two sequences demonstrates that the GSTF can serve for a novel pre-emphasis. A pre-emphasis based on the GSTF information can be applied to any arbitrary sequence type.

Object To enable a retrospective adjustment of image contrast and heart phase in inversion recovery prepared late gadolinium enhancement (LE) imaging in the myocardium. Materials and methods After one inversion pulse, unsegmented data were acquired over multiple cardiac cycles using a radial spoiled gradient-echo sequence with golden angle increments between subsequent readouts. Model-based acceleration of parameter mapping (MAP) was combined with an image registration technique (“MOCO-MAP”) to enable the reconstruction of images with arbitrary inversion time TI. Results MOCO-MAP allowed the reconstruction of LE images with arbitrary TI for arbitrary cardiac phases in four patients suffering from myocardial infarction. Regions with LE agreed well between the MOCO-MAP and the segmented techniques typically applied in clinical routine. Conclusions MOCO-MAP delivers LE images with arbitrary and thus retrospectively optimized contrast between vital and diseased tissue, without the need for time-consuming TI scouting.

Die Magnetresonanzangiographie (MRA) nimmt einen zunehmend groseren Stellenwert in der Beurteilung der arteriellen und venosen Gefasstrombahn von Kopf bis Fus ein. Stetige Verbesserungen in der Scanner- und Sequenztechnologie wie auch der Nachverarbeitungsverfahren konnten die Bildqualitat der MRA derart verbessern, dass in einer Vielzahl von Fallen die diagnostische Katheterangiographie durch die MRA ersetzt werden kann (Abb. 1). Unter Verwendung von Geraten der neuesten Bauart, Oberflachenspulen und Gradientenechosequenzen konnen hoch qualitative dreidimensionale Gefasrekonstruktionen mit hoher Sensitivitat und Spezifitat generiert werden (Collins et al. 2007). Bei der Untersuchung von verkalkten Lasionen kann es zu einer Uberschatzung des Stenosegrades v. a. im Bereich von kleinkalibrigen Gefasen kommen. Prinzipiell wird die native MRA, bei der keine gadoliniumhaltigen Kontrastmittel eingesetzt werden, von der kontrastmittelunterstutzten MRA unterschieden.