[Improved image quality of the cervical spine neck CT using an arm traction device]

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.