Magnetic resonance imaging in the evaluation of cervical foraminal stenosis: comparison of 3D T2 SPACE with sagittal oblique 2D T2 TSE

Objective The oblique orientation of the cervical neural foramina challenges the implementation of a short MRI protocol with concurrent excellent visualization of the spine. While sagittal oblique T2-weighted sequences permit good evaluation of the cervical neuroforamina, all segments may not be equally well depicted on a single sequence and conspicuity of foraminal stenosis may be limited. 3D T2-weighted sequences can be reformatted in arbitrary planes, including the sagittal oblique. We set out to compare 3D T2w SPACE sequences with sagittal oblique reformations and sagittal oblique 2D T2w TSE sequences for the evaluation of cervical foraminal visibility and stenosis. Materials and methods Sixty consecutive patients who underwent MRI of the cervical spine with sagittal oblique 2D T2w TSE and 3D T2w SPACE sequences were included. Image homogeneity of the sequences was evaluated. Imaging sets were assessed for structure visibility and foraminal stenosis by two independent readers. Results of the sequences were compared by Wilcoxon matched-pairs tests. Interreader agreement was evaluated by weighted κ. Results Visibility of most structures was rated good to excellent on both sequences (mean visibility scores ≥ 4.5 of 5), though neuroforaminal contents were better seen on sagittal oblique T2w TSE (mean scores 4.1–4.6 vs. 3.1–4.1 on 3D T2w SPACE, p < 0.01). Stenosis grades were comparable between sequences (mean 1.1–2.6 of 4), with slightly higher values for 3D T2w SPACE at some levels (difference ≤ 0.3 points). Conclusion 3D T2w SPACE is comparable with sagittal oblique 2D T2w TSE in the evaluation of cervical neural foramina.

Imaging Performance of a Multimodal Module to Enhance Preclinical Irradiator Capabilities

This article highlights the performance measurements of an optical device which aims at upgrading preclinical irradiators. The evaluated device allows acquiring X-ray as well as bioluminescence images with a single sensor. The latter consists of a supercooled camera equipped with a 1024x1024 charge coupling device (each element measuring 13x13µm²). X-ray imaging is feasible, thanks to a conversion phosphor screen. Phantom acquisitions revealed a spatial resolution of 2.5 line pairs per millimetre (0.2mm) for Xray imaging and between 0.4 and 0.7mm for bioluminescence images. Image homogeneity was 0.8 for radiographic images with preclinical imaging parameters and higher than 0.9 for optical images. For functional imaging, contrast to noise ratio (CNR) ranged from 1.3 (for contrast of 2:1 and 0.1s acquisition) up to 253 (for contrast of 32:1 and 5s acquisition). CNR was related to acquisition duration. The device’s overall performance revealed that it is suitable to upgrade existing irradiators and improve laboratory capabilities toward image-guided radiotherapy.

Effect of Thermal Insulation on Image Quality and Radiation Dose in Polytrauma Computed Tomography

Purpose: Unintentional drop in body temperature in trauma victims is an independent risk factor for mortality. We aimed to assess the impact of thermal insulation on image quality and radiation dose in polytrauma computed tomography (CT). Methods: Thirteen different insulating covers were used to wrap CT phantoms. Images were assessed subjectively at a radiological workstation and analyzed digitally with dedicated software evaluating the noise intensity, spatial resolution, and image homogeneity. The radiation dose was measured using a dosimeter. Results: Most materials did not cause significant artifacts apart from 2 heating pads. Although the radiation dose was increased by the majority of insulating covers (up to 64.66%), certain covers decreased the absorbed radiation (up to −7.35%). Conclusions: The majority of insulating systems do not cause artifacts in CT scans. When using covers with self-heating warmers, removing the heating pad is suggested due to the risk of considerable artifacts appearing. Certain insulating covers may increase or decrease the radiation dose.