[Improved image quality of the cervical spine neck CT using an arm traction device]. / Verbesserte Bildqualität der Halswirbelsäulen-CT mittels Armzugvorrichtung.

BACKGROUND: The assessment of the cervico-thoracic junction in the neck CT is frequently hampered by streak artifacts from the shoulder girdles. PURPOSE: To evaluate the effects of an optimized patient positioning through the use of an arm traction device. MATERIALS AND METHODS: 25 patients (age [mean ± standard deviation]: 58.9 ± 11.6 years; sex [m:f]: 15:10) underwent a neck CT using an arm traction device together. Further 25 patients underwent this in standard positioning (59.8 ± 15.2 years; 16:9). An experienced neuroradiologist determined the last free accessible vertebra on the CT scout view and assessed the image quality of the intervertebral disc space of the lower neck on a three-point grading scale. The procedure was evaluated by the medical-technical radiology assistants performing it. RESULTS: The last free accessible vertebra on CT scout was statistically significant one vertebra lower using an arm traction device, yielding on average the sixth cervical vertebra (p = 0.010). Subjective image quality increased in all evaluated intervertebral disc spaces (median and absolute frequencies [good/middle/bad]: 1.0 [53/21/8] vs. 2.0 [41/30/24]), resulting in a statistically significant effect between the cervical vertebra 6/7 (p = 0.0041). The traction device approach was rated to be suitable for daily routine in the categories of patient's cooperation (good), comprehensibility for the patient (84%) and management for the assistants (good). CONCLUSION: Using an arm traction device on neck CT both the accessibility of vertebra on CT scout increased and image quality of the cervico-thoracic junction improved. The simply applicable device could be favourable for cooperative patients with lower neck pathology.

Shape Modification is Common in Woven EndoBridge-Treated Intracranial Aneurysms: A Longitudinal Quantitative Analysis Study.

BACKGROUND AND PURPOSE: After endovascular treatment of intracranial aneurysms with the Woven EndoBridge (WEB) device, worsening of aneurysm occlusion or re-opening was reported to be possibly associated with WEB shape modification. This study analyzed quantitatively the WEB shape modification with time in association with anatomic results. MATERIALS AND METHODS: Thirty patients with 32 WEB-treated intracranial aneurysms fulfilled the inclusion criteria of cranial CT at baseline (day of intervention) and a follow-up CT at least >1 months' later (median follow-up time, 11.4 months; interquartile range, 6.5-21.5 months). Adequate occlusion was observed in 84.4%, and aneurysm remnant, in 15.6%. WEB shape modification was quantified by a semiautomated approach on CT scans. Time courses were evaluated graphically and analytically; association analyses were performed by linear mixed-effects regression models. RESULTS: In 29/32 WEB devices (90.6%), the reduction in height was found to be at least 5%. The decrease in height with time was significantly associated with the time interval in days since the intervention (P < .0001): A stronger decrease in WEB height was associated with a longer time since the intervention (median reduction in 1 year, 19.2%; range, 8.6%-52.3%). No significant association was found with the quality of aneurysm occlusion, device size, rupture status of the aneurysm, aneurysm location, and reintervention rate. CONCLUSIONS: Shape modification was common in WEB-treated intracranial aneurysms with a median height reduction of 19.2% in 1 year. The quality of aneurysm occlusion was not associated with WEB modification.

Controllable Non-Markovianity for a Spin Qubit in Diamond.

We present a flexible scheme to realize non-Markovian dynamics of an electronic spin qubit, using a nitrogen-vacancy center in diamond where the inherent nitrogen spin serves as a regulator of the dynamics. By changing the population of the nitrogen spin, we show that we can smoothly tune the non-Markovianity of the electron spin's dynamics. Furthermore, we examine the decoherence dynamics induced by the spin bath to exclude other sources of non-Markovianity. The amount of collected measurement data is kept at a minimum by employing Bayesian data analysis. This allows for a precise quantification of the parameters involved in the description of the dynamics and a prediction of so far unobserved data points.

Influence of intentional femoral component flexion in navigated TKA on gap balance and sagittal anatomy.

PURPOSE: Navigation has proven its ability to accurately restore coronal leg axis; however, for a good clinical outcome, other factors such as sagittal anatomy and balanced gaps are at least as important. In a gap-balanced technique, the size of the flexion gap is equalled to that of the extension gap. Flexion of the femoral component has been described as a theoretical possibility to balance flexion and extension gap. Aim of this study was to assess whether intentional femoral component flexion is helpful in balancing TKA gaps and in restoring sagittal anatomy. METHODS: One hundred and thirty-one patients with TKA were included in this study. Implantation was performed in a navigated, gap-balanced, tibia-first technique. The femoral component flexion needed to equal flexion to extension gap was calculated based upon the navigation data. The sagittal diameter, the anterior and posterior offset were measured pre- and postoperatively based on the lateral radiographs. Medial and lateral gaps in extension and flexion as well as flexion/extension gap differences pre- and postoperatively were analysed. Additionally range of motion (ROM) and patient satisfaction (SF 12) were obtained. RESULTS: To achieve equal flexion and extension gap, the femoral component was flexed in 120 out of 131 patients showing mean flexion of 2.9° (SD 2.2°; navigation data) and 3.1° (SD 2.0°; radiological analysis), respectively. Based on this technique, it was possible to balance the extension gap (<2 mm difference) in 130 out of 131 patients (99%) and the flexion gap in 119 out of 131 (91%). The difference between extension and flexion gap was reduced from 39 to 24 out of 131 patients (81%) on the medial side and from 69 to 28 on the lateral side (79%). The sagittal diameter was restored in 114 out of 131 cases (87%); however, anterior offset was significantly reduced by 1.3 mm (SD 3.9°), and posterior offset was significantly increased by 1.6 mm (SD 3.3°). No correlation between any navigation and radiological parameter was found with ROM and SF 12. CONCLUSIONS: The navigation-based, gap-balanced technique allows intentional flexion of the femoral component in order to balance gaps in more than 90% of primary TKA cases. Simultaneously, the sagittal diameter is restored in 87% of patients. However, to achieve equal gaps, the posterior offset is significantly increased by 1.6 mm and the femoral component is flexed by 3°. To evaluate the effect of this technique on the clinical outcome, future studies are needed. LEVEL OF EVIDENCE: II.