The authors present an automatic system to detect cerebral aneurysms in multimodal angiographic data sets. The system proved as a suitable computer-aided detection tool to help radiologists find cerebral aneurysms.

Time-resolved magnetic resonance imaging (4DMRI) provides spatial motion information with high soft-tissue contrast. This study exploits the potential of 4DMRI by investigation of inter-and intrafractional pancreas motion and deformation with different patient immobilization devices. In total, 150 4DMRI scans were acquired for a cohort of 5 volunteers, each was scanned in 10 imaging sessions using three different positioning modes (flat table top (FTT), vacuum bag (VB), abdominal corset (AC)), respectively, to simulate repeated 4DMR imaging sessions of patients during fractionated radiotherapy. Large pancreatic motion variations were observed throughout the volunteers with mean inferior-superior (IS) motion amplitudes up to 28.5/21.9 mm for FTT/VB measurements, which were reduced by 48%/34%, respectively, by using abdominal corsets. Small IS motion reductions were present for vacuum bag measurements, compared to flat table top measurements. Corset measurements additionally showed an improved motion reproducibility between different days by more than 60% compared to FTT and VB. In anterior-posterior direction, motion amplitudes were reduced by 69%/60% for corset measurement, compared to FTT/VB, and their day-to-day fluctuations were reduced by approximately 130%. With respect to respiration-induced pancreas deformations, the pancreas showed the lowest deformation and highest reproducibility for corset measurements in 4 out of 5 volunteers. Moreover, both, the VB and AC setup showed a generally improved setup reproducibility compared to the non-immobilized flat table top setting. All in all, in this study, abdominal corsets showed to reduce both pancreatic motion and deformations. Moreover, by using corsets it is possible to improve the reproducibility of both pancreatic motion and deformation, which are important factors in radiotherapy treatments. Therefore, radiotherapy treatments of pancreatic cancer patients with abdominal corsets may be a viable option for patients with large internal organ motion amplitudes and may lead to a better consistency of the treatment planning and delivery situation.

Objectives Dual-energy computed tomography (DECT)–derived quantification of iodine concentration (IC) is increasingly used in oncologic imaging to characterize lesions and evaluate treatment response. However, only limited data are available on intraindividual consistency of IC and its variation. This study investigates the longitudinal reproducibility of IC in organs, vessels, and lymph nodes in a large cohort of healthy patients who underwent repetitive DECT imaging. Materials and Methods A total of 159 patients, who underwent a total of 469 repetitive (range, 2–4), clinically indicated portal-venous phase DECT examinations of the chest and abdomen, were retrospectively included. At time of imaging, macroscopic tumor burden was excluded by follow-up imaging (≥3 months). Iodine concentration was measured region of interest-based (N = 43) in parenchymatous organs, vessels, lymph nodes, and connective tissue. Normalization of IC to the aorta and to the trigger delay as obtained from bolus tracking was performed. For statistical analysis, intraclass correlation coefficient and modified variation coefficient (MVC) were used to assess intraindividual agreement of IC and its variation between different time points, respectively. Furthermore, t tests and analysis of variance with Tukey-Kramer post hoc test were used. Results The mean intraclass correlation coefficient over all regions of interest was good to excellent (0.642–0.936), irrespective of application of normalization or the normalization technique. Overall, MVC ranged from 1.8% to 25.4%, with significantly lower MVC in data normalized to the aorta (5.8% [1.8%–15.8%]) in comparison with the MVC of not normalized data and data normalized to the trigger delay (P < 0.01 and P = 0.04, respectively). Conclusions Our study confirms intraindividual, longitudinal variation of DECT-derived IC, which varies among vessels, lymph nodes, organs, and connective tissue, following different perfusion characteristics; normalizing to the aorta seems to improve reproducibility when using a constant contrast media injection protocol.