Unsupervised clustering analysis-based characterization of spatial profiles of inaccuracy in apparent diffusion coefficient values with varying acquisition plan orientation and diffusion weighting gradient direction - a large multicenter phantom study.

This large multicenter study of 37 magnetic resonance imaging scanners aimed at characterizing, for the first time, spatial profiles of inaccuracy (namely, Δ-profiles) in apparent diffusion coefficient (ADC) values with varying acquisition plan orientation and diffusion weighting gradient direction, using a statistical approach exploiting unsupervised clustering analysis. A diffusion-weighted imaging (DWI) protocol (b-value: 0-200-400-600-800-1000 s mm) with different combinations of acquisition plan orientation (axial/sagittal/coronal) and diffusion weighting gradient direction (anterior-posterior/left-right/feet-head) was acquired on a standard water phantom. For each acquisition setup, Δ-profiles along the 3 main orthogonal directions were characterized by fitting data with a second order polynomial function ().

On the dependence of quantitative diffusion-weighted imaging on scanner system characteristics and acquisition parameters: A large multicenter and multiparametric phantom study with unsupervised clustering analysis.

Purpose: The purpose of this multicenter phantom study was to exploit an innovative approach, based on an extensive acquisition protocol and unsupervised clustering analysis, in order to assess any potential bias in apparent diffusion coefficient (ADC) estimation due to different scanner characteristics. Moreover, we aimed at assessing, for the first time, any effect of acquisition plan/phase encoding direction on ADC estimation.

Methods: Water phantom acquisitions were carried out on 39 scanners.

Back to the future in traumatic fracture shapes of lumbar spine: An analysis of risk of kyphosis after conservative treatment.

Introduction: Nonosteoporotic burst vertebral fracture could commonly be treated with conservative or surgical approach. Currently, decision-making process is based on thoracolumbar (TL) AO spine severity injury score. However, some factors could affect posttraumatic kyphosis (PTK) and could be taken into account.

Effectiveness and reliability of cannulated fenestrated screws augmented with polymethylmethacrylate cement in the surgical treatment of osteoporotic vertebral fractures.

Background: Implants' stability, especially in osteoporosis patients, is a challenging matter. Nowadays, the adoption of cannulated fenestrated screws augmented with polymethylmethacrylate cement (PMMA CSF) is described by some authors. This single-center, retrospective observational study aims to evaluate the long-term effectiveness, reliability, and mechanical performances of this type of screws in osteoporotic fractures.

Assessment of the SARS-CoV-2 basic reproduction number, , based on the early phase of COVID-19 outbreak in Italy.

As of March 12 Italy has the largest number of SARS-CoV-2 cases in Europe as well as outside China. The infections, first limited in Northern Italy, have eventually spread to all other regions. When controlling an emerging outbreak of an infectious disease it is essential to know the key epidemiological parameters, such as the basic reproduction number , i.

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.

Dependence of apparent diffusion coefficient measurement on diffusion gradient direction and spatial position - A quality assurance intercomparison study of forty-four scanners for quantitative diffusion-weighted imaging.

Purpose: To propose an MRI quality assurance procedure that can be used for routine controls and multi-centre comparison of different MR-scanners for quantitative diffusion-weighted imaging (DWI).

Materials And Methods: 44 MR-scanners with different field strengths (1 T, 1.5 T and 3 T) were included in the study.

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.

Different pedicle osteosynthesis for thoracolumbar vertebral fractures in elderly patients.

Introduction: Pedicle screws' stability, especially in osteoporotic fractures, is a really problem for spinal surgeons. Nowadays, little is known about the influence of different screw types and amount of cement applied. This single-center retrospective observational study has the aim of evaluating the middle- to long-term mechanical performances of different types of screws in elderly patients with thoracolumbar fractures.

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

Purpose: 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).

Materials And Methods: Twenty-six centers (35 MR scanners with field strengths: 1T, 1.5T, and 3T) were enrolled in the study.

Cortical ischemic lesion burden measured by DIR is related to carotid artery disease severity.

Background: Over time, exposure to cerebrovascular risk factors and carotid artery disease may cause multiple asymptomatic brain cortical and subcortical microinfarcts, which are commonly found at brain autopsy. So far, lack of convenient neuroimaging tools limited the investigation of grey matter ischemic damage in vivo. We applied the Double Inversion Recovery (DIR) sequence to explore the impact of carotid artery disease on intracortical ischemic lesion load in vivo, taking into account the impact of demographic characteristics and vascular risk factors.

Quantification of dose nonuniformities by voxel-based dosimetry in patients receiving 90Y-ibritumomab-tiuxetan.

Unlabelled: Abstract Objective: To assess the impact of nonuniform dose distribution within lesions and tumor-involved organs of patients receiving Zevalin(®), and to discuss possible implications of equivalent uniform biological effective doses (EU-BED) on treatment efficacy and toxicity. MATLAB™ -based software for voxel-based dosimetry was adopted for this purpose.

Methods: Eleven lesions from seven patients with either indolent or aggressive non-Hodgkin lymphoma were analyzed, along with four organs with disease.

90Y PET-based dosimetry after selective internal radiotherapy treatments.

Objectives: The decay of 90Y has a minor branch to the O+ first excited state of 89Zr, the de-excitation of which to the fundamental state is followed by a β+–β- emission that has been used recently for biodistribution assessment after selective internal radiotherapy (SIRT) treatments. The purpose of the present study is to demonstrate the feasibility of 90Y PET imaging for dose assessment after radioembolization with 90Y microspheres.

Methods: Activity quantification was validated through preliminary phantom studies using a cylindrical body phantom composed of six inserts of different volumes filled with a calibrated amount of 90Y microspheres.

Three-dimensional patient-specific dosimetry in radioimmunotherapy with 90Y-ibritumomab-tiuxetan.

Aim of the present article was to perform three-dimensional (3D) single photon emission tomography-based dosimetry in radioimmunotherapy (RIT) with (90)Y-ibritumomab-tiuxetan. A custom MATLAB-based code was used to elaborate 3D images and to compare average 3D doses to lesions and to organs at risk (OARs) with those obtained with planar (2D) dosimetry. Our 3D dosimetry procedure was validated through preliminary phantom studies using a body phantom consisting of a lung insert and six spheres with various sizes.