A New Approach for Photorealistic Visualization of Rendered Computed Tomography Images.

OBJECTIVE: Classical single-colored or multicolored 3-dimensional (3D) visualization of sectional images lacked in being realistic and revealed limited anatomical discrimination. Recently, a new technique called cinematic volume rendering for 3D reconstruction of computed tomography has been developed. The aim of this study was to analyze this new visualization algorithm from a technical perspective and to investigate potential benefits for neurosurgical applications. METHODS: A standard test in computer graphics called Cornell Box was adapted and applied for reproducibility of light effects in cinematic rendering opposed to classic rendering methods. Simulation of distinct camera effects such as variable apertures, exposition time, optics, and surface refinements are presented in a human skull, respectively. Postprocessing capabilities allow for immediate clinical use. RESULTS: This volume-rendering technique generates cadaver-like 3D reconstructions. By considering complex interactions between a scanned object and dynamic light patterns, a cinematic illumination of a 3D surface reconstruction can be achieved. A spinal tumor case and a complex intracranial carotid artery aneurysm are presented, comparing all available rendering techniques. Cinematic rendering results in greater spatial discrimination of neighboring anatomical structures. CONCLUSIONS: This technical and clinical description focuses on the neurosurgical relevance of a new rendering technique. Considering the improved image impression of cinematic rendering and viewers' perception, it seems likely that the technique will gain wide acceptance in the clinical routine.

23Na MRI and myometry to compare eplerenone vs. glucocorticoid treatment in Duchenne dystrophy.

In this pilot study we tested whether a low dose application of a mild diuretic substance such as eplerenone is beneficial in early stages of Duchenne muscular dystrophy using 23Na und 1H imaging, myometry, and clinical testing versus the glucocorticoid gold standard. Two 7-years old patients with DMD were examined on a 3T MRI system. 1H MRI and 23Na density-adapted 3-dimensional radial MRI sequences were performed both before and 1, 3 and 6 months after therapy with eplerenone respectively cortisone. We quantified fatty infiltration on T1-weighted images using subcutaneous fat as reference and fat fraction with a two-point DIXON sequence. Muscle oedema was quantified on STIR images and DIXON water maps with background noise as reference. We quantified Na+ by a muscular tissue concentration sequence with a 51.3mM Na+ with 5% agarose reference tube. A Na+ IR-sequence was used for determination of mainly myoplasmic Na+. Correspondingly myometry of muscles and tendons were assessed. Clinical tests (i.e. 4-steps-test) and blood counts (i.e. K+) were done by a pediatrician. Under eplerenone therapy we detected a reduction of muscular oedema, intracellular-weighted sodium IR signal and muscular sodium concentration. The oedema reduction in the DMD patient receiving eplerenone was more pronounced to the patient with cortisone. Myometric-measured tissue parameters such as muscle stiffness had a more pronounced effect in the child treated with eplerenone after a first increase in muscle stiffness both after eplerenone and cortisone treatment. Clinical abilities during both therapies were mostly constant. Eplerenone might be a possible new therapy option in DMD patients.

New bone post-processing tools in forensic imaging: a multi-reader feasibility study to evaluate detection time and diagnostic accuracy in rib fracture assessment.

PURPOSE: The aim of this multi-reader feasibility study was to evaluate new post-processing CT imaging tools in rib fracture assessment of forensic cases by analyzing detection time and diagnostic accuracy. MATERIALS AND METHODS: Thirty autopsy cases (20 with and 10 without rib fractures in autopsy) were randomly selected and included in this study. All cases received a native whole body CT scan prior to the autopsy procedure, which included dissection and careful evaluation of each rib. In addition to standard transverse sections (modality A), CT images were subjected to a reconstruction algorithm to compute axial labelling of the ribs (modality B) as well as "unfolding" visualizations of the rib cage (modality C, "eagle tool"). Three radiologists with different clinical and forensic experience who were blinded to autopsy results evaluated all cases in a random manner of modality and case. RESULTS: Rib fracture assessment of each reader was evaluated compared to autopsy and a CT consensus read as radiologic reference. A detailed evaluation of relevant test parameters revealed a better accordance to the CT consensus read as to the autopsy. Modality C was the significantly quickest rib fracture detection modality despite slightly reduced statistic test parameters compared to modalities A and B. CONCLUSION: Modern CT post-processing software is able to shorten reading time and to increase sensitivity and specificity compared to standard autopsy alone. The eagle tool as an easy to use tool is suited for an initial rib fracture screening prior to autopsy and can therefore be beneficial for forensic pathologists.