A straightforward multiparametric quality control protocol for proton magnetic resonance spectroscopy: Validation and comparison of various 1.5 T and 3 T clinical scanner systems

Purpose: The aim of this study was to propose and validate across various clinical scanner systems a straightforward multiparametric quality assurance procedure for proton magnetic resonance spectroscopy (MRS). Methods: Eighteen clinical 1.5 T and 3 T scanner systems for MRS, from 16 centres and 3 different manufacturers, were enrolled in the study. A standard spherical water phantom was employed by all centres. The acquisition protocol included 3 sets of single (isotropic) voxel (size 20 mm) PRESS acquisitions with unsuppressed water signal and acquisition voxel position at isocenter as well as off-center, repeated 4/5 times within approximately 2 months. Water peak linewidth (LW) and area under the water peak (AP) were estimated. Results: LW values [mean (standard deviation)] were 1.4 (1.0) Hz and 0.8 (0.3) Hz for 3 T and 1.5 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficient of variation of LW and AP for different spatial positions of acquisition voxel were 43% (20%) and 11% (11%), respectively. The mean (standard deviation) phantom T2 values were 1145 (50) ms and 1010 (95) ms for 1.5 T and 3 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficients of variation for repeated measurements of LW, AP and T2 were 25% (20%), 10% (14%) and 5% (2%), respectively. Conclusions: We proposed a straightforward multiparametric and not time consuming quality control protocol for MRS, which can be included in routine and periodic quality assurance procedures. The protocol has been validated and proven to be feasible in a multicentre comparison study of a fairly large number of clinical 1.5 T and 3 T scanner systems

Clinical and radiological union rate evaluation of type 2 odontoid fractures: A comparison between anterior screw fixation and halo vest in elderly patients

Purpose: Odontoid fracture is a very common cervical injury, especially in elderly patients. Despite the high frequency, the appropriate management is still debated. The aim of this study is to evaluate clinical and radiological outcomes after anterior screw fixation or halo vest (HV) in type II odontoid fracture in elderly patients. Materials and Methods: Between January 2013 and December 2015, 135 consecutive patients affected by odontoid process were found. According to inclusion and exclusion criteria, 57 patients were included in the study. Patients were evaluated with visual analog scale (VAS), Smiley–Webster Scale (SWS), Italian Version of the Neck Disability Index (NDI), and patient satisfaction during follow-up. Furthermore, radiological data were evaluated for bone healing. Student's t-test or Fisher's exact test was used between groups, analyzing radiological and clinical results, and level of statistical significance was set at P < 0.05. Results: Seventeen patients were female and 40 were male. Twenty-seven patients were included in surgical group (SG) while 30 were included in HV group with a mean follow-up of 37.74 ± 10.52 months. A significant difference (P 0.05); SG reached higher satisfaction than HV group (P = 0.0271). Conclusions: Both treatments are equivalent in terms of clinical outcomes, and they are a valuable choice in the management of type II odontoid fracture. However, it must be considered that patients could slightly tolerate HV and may need a change of treatment

Radiation Environment in the ITER Neutral Beam Injector Prototype

We study the radiation environment in MITICA, the prototype of the ITER neutral beam injector, during deuterium operation. ITER is a scientific challenge: one of the several critical issues to solve is the compatibility to ionizing radiation of diagnostics components placed near the plasma vessel. In fact, non negligible fluxes of neutrons and photons are expected from deuterium-deuterium reactions, also from a major peripheral component such as the Neutral Beam Injector. After evaluating the results of Monte Carlo simulations on the expected environment, we determine the risk of malfunctions due to ionizing radiation in control and diagnostic electronics placed close to the injector vessel. The risk on different families of electronic devices is assessed, focusing separately on displacement damage, total ionizing dose, and single event effects

Is vertebral stenting kyphoplasty a good choice in the treatment of osteoporotic vertebral fracture? A series of 47 patients (v2)

Background: The incidence of vertebral fragility fracture is increasing over last three decades with an essential impact on quality of life. Some devices were proposed to improve conventional kyphoplasty in the last five years, known as vertebral stenting kyphoplasty (VSK). Materials and methods: All osteoporotic vertebral fractures (OVF) treated with VSK, single-level fracture without neurological impairment, and with more than 24 months of follow-up were included in the study. We recorded fracture types according to DGOU classification, fracture level, regional kyphosis angle (RKA), Oswestry disability index (ODI), and complications. Results: Forty-seven consecutive patients were included. RKA significantly improved from pre to postoperative values (p&lt;0.000001) and to follow-up values (p&lt;0.00001). A significant difference was found between preoperative RKA of (OF2+OF3) and OF4 (p&lt;0.00001), confirmed immediately after surgery (p= 0.005425) and at last follow up (p= 0.000947). A significant difference was found in correction of RKA between (OF2+OF3) and OF4 at injury time and after treatment (p&lt;0.00001), and it was confirmed at the last follow-up (p=0.000026). ODI showed a significant difference between (OF2+OF3) and OF4 type of fractures (p=0.038216). We recorded five complications: 2 cases of leakage without neurological impairment, two progressions of kyphosis, and one implant migration. Conclusions: VSK is an excellent and reliable option in the treatment of OVF, with good clinical results and preservation of obtained RKA at the time of treatment. However, in case of vertebral collapse with the involvement of both vertebral plates, surgeons must be aware of possible implant failure or migration. Level of evidence: 4

Response of AGATA segmented HPGe detectors to gamma-rays up to 15.1 MeV

In many in-beam gamma spectroscopy experiments the detection of high-energy gamma rays in the range up to 10-20 MeV is of primary importance. New generation high-resolution gamma-ray spectrometers like AGATA and GRETA are composed of position sensitive segmented HPGe detectors and provide a reconstruction of the gamma-ray tracks. The performance of AGATA detectors in this energy range has, however, never been studied in detail. A measurement of the response to 15.1 MeV gamma rays has been performed using two HPGe triple clusters of the AGATA Demonstrator array, operating at LNL-INFN. This manuscript presents the preliminary results of a test of the AGATA detectors for the measurement of high-energy gamma rays, in terms of detection efficiency, energy resolution, tracking and performance of the pulse shape analysis (PSA) algorithms

Quality assurance multicenter comparison of different MR scanners for quantitative diffusion-weighted imaging

To propose a magnetic resonance imaging (MRI) quality assurance procedure that can be used for multicenter comparison of different MR scanners for quantitative diffusion-weighted imaging (DWI)