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<0.000001) and to follow-up values (p<0.00001). A significant difference was found between preoperative RKA of (OF2+OF3) and OF4 (p<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<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.

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. DWI acquisitions (b-value = 0-200-400-600-800-1000 s/mm2) with different acquisition plans (axial, coronal, sagittal) and phase encoding directions (anterior/posterior and right/left, for the axial acquisition plan), for 3 orthogonal diffusion weighting gradient directions, were performed. For each acquisition setup, ADC values were measured in-center and off-center (6 different positions), resulting in an entire dataset of 84 × 39 = 3276 ADC values. Spatial uniformity of ADC maps was assessed by means of the percentage difference between off-center and in-center ADC values (Δ). RESULTS: No significant dependence of in-center ADC values on acquisition plan/phase encoding direction was found. Ward unsupervised clustering analysis showed 3 distinct clusters of scanners and an association between Δ-values and manufacturer/model, whereas no association between Δ-values and maximum gradient strength, slew rate or static magnetic field strength was revealed. Several acquisition setups showed significant differences among groups, indicating the introduction of different biases in ADC estimation. CONCLUSIONS: Unsupervised clustering analysis of DWI data, obtained from several scanners using an extensive acquisition protocol, allows to reveal an association between measured ADC values and manufacturer/model of scanner, as well as to identify suboptimal DWI acquisition setups for accurate ADC estimation.

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. MATERIALS AND METHODS: All the patients surgically treated from January 2009 to December 2019 with PMMA CSF were evaluated and submitted to the inclusion and exclusion criteria. Clinical and radiological evaluations were performed at pre- and post-surgery time and at the follow-up (FU). Loss of correction in the sagittal plane (bisegmental Cobb angle), kyphosis angle of the fracture (fractured vertebral angle), loosening of pedicle screws (screw's apex vertebral body's anterior cortex mean gap called SAAC gap and screw's apex vertebral body's superior endplate mean gap called SASE gap), visual analog scale, and Oswestry disability index scores were evaluated. RESULTS: One hundred and sixty-three patients (58 males and 105 females) aged over 65 years affected by vertebral osteoporotic fractures were included in the study. At FU, we do not found significant differences in radiological items in respect to the postoperative period. Only one case of loosening and 18 cases of cement leaking (without neurological impairments) were found. Clinical scores improvement was significant in the interval between preoperative and FU. CONCLUSIONS: PMMA CSF seems to can guarantee good efficacy and effectiveness in the surgical treatment of vertebral fractures in osteoporosis.

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. The aim of the present study is to identify if axial and sagittal fracture shape and initial kyphosis are the risk factors for PTK. MATERIALS AND METHODS: All consecutive patients treated between 2016 and 2017 for TL vertebral fracture with conservative treatment were retrospectively evaluated in the study. Only type A3 and A4 vertebral fractures were included in the study. Patients suffering from osteoporosis or other metabolic bone disease, aged above 60 years old were excluded from the study. Initial and 6 months X-ray from injury were analyze to evaluate local kyphosis and region of injury while initial assessment was performed with computed tomography to better identify fracture type and in some cases magnetic resonance imaging to exclude posterior ligament complex injury. Axial and sagittal view of the vertebral plate was analyzed and classified in three shapes according to fragment comminution and dislocation. Statistical analysis was performed trough STATA13 software. Student's t-test was used to evaluate the differences between initial and follow up kyphosis; odds ratio (OR) was used to evaluate the role of initial kyphosis, vertebral sagittal and axial fracture shape as a risk factor for PTK. Kruskal-Wallis test was used to assess the differences among vertebral shape fractures and final kyphosis. Fisher's exact test was used to assess the differences between fracture patterns and final kyphosis. RESULTS: An initial kyphosis >10° (OR 36.75 P = 0.015), shape c vertebral plate (OR 147 P = 0.0015), and sagittal shape 3 (OR 32.25 P = 0.0025) are strongly related with PTK. Kruskal-Wallis test revealed a statistically significant difference among axial fracture shape (P < 0.0001) and sagittal fracture shape (P = 0.004) and also for initial kyphosis >10° (P < 0.0001). Fisher's exact test showed a significant difference for final kyphosis among pattern c3 and other patterns of fracture (P = 0.0001). CONCLUSIONS: A burst type lumbar vertebral fracture affecting a patient with initial local kyphosis >10° and comminution and displacement of vertebral plate and vertebral body is at high risk to develop a local kyphosis >20° in the follow-up if treated conservatively.

Assessment of the SARS-CoV-2 basic reproduction number, R 0, based on the early phase of COVID-19 outbreak in Italy.

As of March 12th 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 R 0, i.e. the average number of secondary infections caused by one infected individual during his/her entire infectious period at the start of an outbreak. Previous work has been limited to the assessment of R 0 analyzing data from the Wuhan region or Mainland China. In the present study the R 0 value for SARS-CoV-2 was assessed analyzing data derived from the early phase of the outbreak in Italy. In particular, the spread of SARS-CoV-2 was analyzed in 9 cities (those with the largest number of infections) fitting the well-established SIR-model to available data in the interval between February 25-March 12, 2020. The findings of this study suggest that R 0 values associated with the Italian outbreak may range from 2.43 to 3.10, confirming previous evidence in the literature reporting similar R 0 values for SARS-CoV-2.

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. DWI acquisitions (b-value range 0-1000 s/mm2), with three different orthogonal diffusion gradient directions, were performed for each MR-scanner. All DWI acquisitions were performed by using a standard spherical plastic doped water phantom. Phantom solution ADC value and its dependence with temperature was measured using a DOSY sequence on a 600 MHz NMR spectrometer. Apparent diffusion coefficient (ADC) along each diffusion gradient direction and mean ADC were estimated, both at magnet isocentre and in six different position 50 mm away from isocentre, along positive and negative AP, RL and HF directions. RESULTS: A good agreement was found between the nominal and measured mean ADC at isocentre: more than 90% of mean ADC measurements were within 5% from the nominal value, and the highest deviation was 11.3%. Away from isocentre, the effect of the diffusion gradient direction on ADC estimation was larger than 5% in 47% of included scanners and a spatial non uniformity larger than 5% was reported in 13% of centres. CONCLUSION: ADC accuracy and spatial uniformity can vary appreciably depending on MR scanner model, sequence implementation (i.e. gradient diffusion direction) and hardware characteristics. The DWI quality assurance protocol proposed in this study can be employed in order to assess the accuracy and spatial uniformity of estimated ADC values, in single- as well as multi-centre studies.

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 T2values 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.

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. MATERIALS AND METHODS: A total of 91 patients (37 males and 54 females), treated between 2011 and 2016, affected by somatic osteoporotic fractures aged over 65 years were treated. We divided patients into three different populations: solid screws, cannulated screws and cannulated screws augmented with poly methyl methacrylate cement (PMMA). Patients were radiologically evaluated with X-rays in pre- and post-surgery and at the follow-up (FU). Clinical evaluations were made with VAS and Oswestry Disability Index. RESULTS: A total of 636 screws were implanted (222 pedicle screws, 190 cannulated and 224 cannulated screws with PMMA augmentation). At FU, we found significative differences between populations in terms of mechanical performances. We founded five cases of loosening; these were reported in solid screws group and in cannulated screws one. No mechanical failures were reported in cannulated screws with augmentation of PMMA. No rods breakage cases were reported. CONCLUSION: All stabilization methods showed good clinical results, but cannulated screws augmented with PMMA seem to provide better implant stability with the lowest rate of loosening. These slides can be retrieved under Electronic Supplementary Material.

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) between groups was found for pseudoarthrosis, with a lower rate for SG. No significant differences in term of VAS, NDI, and SWS were found between groups (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.

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. Two different DWI acquisition series (b-value ranges 0-1000 and 0-3000 s/mm(2) , respectively) were performed for each MR scanner. All DWI acquisitions were performed by using a cylindrical doped water phantom. Mean apparent diffusion coefficient (ADC) values as well as ADC values along each of the three main orthogonal directions of the diffusion gradients (x, y, and z) were calculated. Short-term repeatability of ADC measurement was evaluated for 26 MR scanners. RESULTS: A good agreement was found between the nominal and measured mean ADC over all the centers. More than 80% of mean ADC measurements were within 5% from the nominal value, and the highest deviation and overall standard deviation were 9.3% and 3.5%, respectively. Short-term repeatability of ADC measurement was found <2.5% for all MR scanners. CONCLUSION: A specific and widely accepted protocol for quality controls in DWI is still lacking. The DWI quality assurance protocol proposed in this study can be applied in order to assess the reliability of DWI-derived indices before tackling single- as well as multicenter studies.

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. METHODS: DIR was acquired in 62 patients with common cerebrovascular risk factors stratified in three groups according to carotid artery disease severity. Intracortical lesions scored on DIR (DIRlns) were classified by vascular territory, lobe and hemisphere. White matter hyperintensities (WMHs) volume was also quantified on Fluid Attenuated Inversion Recovery sequence (FLAIR). RESULTS: Among demographic characteristics and cerebrovascular risk variables explored, General Linear Model indicated that age and carotid artery disease were significantly associated to DIRlns. After correcting for age, DIRlns load was found to be significantly dependent on carotid artery stenosis severity (F(2, 58) = 5.56, p = 0.006). A linear positive correlation between DIRlns and WMHs was found after correcting for age (p = 0.003). CONCLUSIONS: Carotid disease severity is associated with DIRlns accrual. Microembolism and impaired cerebral hemodynamics may act as physiopathological mechanisms underlying cortical ischemic damage. The role of other factors, such as small vessel disease and the possible interaction with carotid disease, remains to be further explored.

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. Absorbed doses were estimated by a direct integration of single-voxel kinetic data from serial tomographic images. After proper corrections, differential BED distributions and surviving cell fractions were estimated, allowing for the calculation of EU-BED. To quantify dose uniformity in each target area, a heterogeneity index was defined. RESULTS: Average doses were below those prescribed by conventional radiotherapy to eradicate lymphoma lesions. Dose heterogeneity and effect on tumor control varied among lesions, with no apparent relation to tumor mass. Although radiation doses to involved organs were safe, unexpected liver toxicity occurred in one patient who presented with a pattern of diffuse infiltration. CONCLUSION: Voxel-based dosimetry and radiobiologic modeling can be successfully applied to lesions and tumor-involved organs, representing a methodological advance over estimation of mean absorbed doses. However, effects on tumor control and organ toxicity still cannot be easily predicted.

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 ß+­ß- 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. A GE Discovery ST PET/CT scanner provided with bismuth germinate (BGO) crystals was used for image acquisition. Images were reconstructed with an ordered subset expectation­maximization method. The effect of object size and the effect of the number of iterations on dose evaluation and volume recovery were investigated. Microsphere dose distribution was then evaluated on one patient (one lesion) who underwent liver SIRT treatment. Dose calculations were made with a MATLAB-based code developed in our department. Dedicated Monte Carlo calculations were executed to evaluate dose S-values for the 90Y source. The activity distribution derived from 90Y PET acquisitions was convolved with the voxel S-values to obtain a three-dimensional absorbed dose distribution and dose­volume histograms. RESULTS: Dosimetry studies carried out on the body phantom with ordered subset expectation­maximization algorithm, three iterations, provided an accuracy of 7.62% in determining the absorbed dose in the largest insert. The dose difference increases as the insert size reduces. Preliminary results on a patient provided a high-resolution absorbed dose distribution map. An average dose of 139.3 Gy was evaluated for the tumor area, with a maximum dose as high as 237.9 Gy. The absorbed dose to the healthy liver was below the tolerance dose of 35 Gy (33.8 Gy). A clear correlation between absorbed dose and tumor response was observed at 18F-fluorodeoxyglucose PET acquired 6 months after treatment. CONCLUSION: According to our experience, 90Y PET is a promising and reliable technique for microsphere dose assessment and might pave the way for a patient-specific PET-based dosimetry after liver SIRT treatments.

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. In phantom study, the accuracy of dose determination of our imaging protocol decreased when the object volume decreased below 5 mL, approximately. The poorest results were obtained for the 2.58 mL and 1.30 mL spheres where the dose error evaluated on corrected images with regard to the theoretical dose value was -12.97% and -18.69%, respectively. Our 3D dosimetry protocol was subsequently applied on four patients before RIT with (90)Y-ibritumomab-tiuxetan for a total of 5 lesions and 4 OARs (2 livers, 2 spleens). In patient study, without the implementation of volume recovery technique, tumor absorbed doses calculated with the voxel-based approach were systematically lower than those calculated with the planar protocol, with average underestimation of -39% (range from -13.1% to -62.7%). After volume recovery, dose differences reduce significantly, with average deviation of -14.2% (range from -38.7.4% to +3.4%, 1 overestimation, 4 underestimations). Organ dosimetry in one case overestimated, in the other underestimated the dose delivered to liver and spleen. However, both for 2D and 3D approach, absorbed doses to organs per unit administered activity are comparable with most recent literature findings.