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1.
Heliyon ; 10(11): e31995, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38868009

ABSTRACT

The corrosion behavior of alloy Ni 201 in molten sodium hydroxide (NaOH) at 600 °C was investigated at varying basicity levels of the molten NaOH. The ability for Ni 201 to form passivating oxides was investigated after immersion tests varying from 70 to 340 h under atmospheres of argon and argon with different partial pressure of water. Morphology and thicknesses of the corrosion products were characterized by Scanning Electron Microscopy (SEM) and crystallography of the corrosion products by X-ray Diffraction (XRD). Dynamic polarizations were made to investigate the effects of basicity and electrochemical potential. The results showed that Ni 201 corroded at a reduced rate in molten acidic NaOH compared to neutral NaOH due to the formation of NiO. The oxide scales formed on Ni 201 in acidic NaOH were shown to grow non-parabolically and did not result in full corrosion protection as the oxide scales showed crack development over time.

2.
Materials (Basel) ; 17(11)2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38894038

ABSTRACT

General interest in the deployment of molten salt reactors (MSRs) is growing, while the available data on uranium-containing fuel salt candidates remains scarce. Thermophysical data are one of the key parameters for reactor design and understanding reactor operability. Hence, filling in the gap of the missing data is crucial to allow for the advancement of MSRs. This study provides novel data for two eutectic compositions within the NaF-KF-UF4 ternary system which serve as potential fuel candidates for MSRs. Experimental measurements include their melting point, density, fusion enthalpy, and vapor pressure. Additionally, their boiling point was extrapolated from the vapor pressure data, which were, at the same time, used to determine the enthalpy of vaporization. The obtained thermodynamic values were compared with available data from the literature but also with results from thermochemical equilibrium calculations using the JRCMSD database, finding a good correlation, which thus contributed to database validation. Preliminary thoughts on fluoride salt reactor operability based on the obtained results are discussed in this study.

3.
Neurosurg Rev ; 45(1): 479-490, 2022 Feb.
Article in English | MEDLINE | ID: mdl-33905002

ABSTRACT

Risks and survival times of ventriculoperitoneal (VP) shunts implanted due to hydrocephalus after craniotomies for brain tumors are largely unknown. The purpose of this study was to determine the overall timing of VP shunting and its failure after craniotomy for brain tumors in adults. The authors also wished to explore risk factors for early VP shunt failure (within 90 days). A population-based consecutive patient cohort of all craniotomies for intracranial tumors leading to VP shunt dependency in adults (> 18 years) from 2004 to 2013 was studied. Patients with pre-existing VP shunts prior to craniotomy were excluded. The survival time of VP shunts, i.e., the shunt longevity, was calculated from the day of shunt insertion post-craniotomy for a brain tumor until the day of shunt revision requiring replacement or removal of the shunt system. Out of 4774 craniotomies, 85 patients became VP shunt-dependent (1.8% of craniotomies). Median time from craniotomy to VP shunting was 1.9 months. Patients with hydrocephalus prior to tumor resection (N = 39) had significantly shorter time to shunt insertion than those without (N = 46) (p < 0.001), but there was no significant difference with respect to early shunt failure. Median time from shunt insertion to shunt failure was 20 days (range 1-35). At 90 days, 17 patients (20%) had confirmed shunt failure. Patient age, sex, tumor location, primary/secondary craniotomy, extra-axial/intra-axial tumor, ventricular entry, post-craniotomy bleeding, and infection did not show statistical significance. The risk of early shunt failure (within 90 days) of shunts after craniotomies for brain tumors was 20%. This study can serve as benchmark for future studies.


Subject(s)
Brain Neoplasms , Hydrocephalus , Adult , Brain Neoplasms/surgery , Craniotomy , Humans , Hydrocephalus/etiology , Hydrocephalus/surgery , Retrospective Studies , Treatment Outcome , Ventriculoperitoneal Shunt/adverse effects
5.
Neurosurg Rev ; 43(1): 141-151, 2020 Feb.
Article in English | MEDLINE | ID: mdl-30120611

ABSTRACT

The efficacy of tumor removal via craniotomies on preoperative hydrocephalus (HC) in adult patients with intracranial tumors is largely unknown. Therefore, we sought to evaluate the effect of tumor resection in patients with preoperative HC and identify the incidence and risk factors for postoperative VP shunt dependency. All craniotomies for intracranial tumors at Oslo University Hospital in patients ≥ 18 years old during a 10-year period (2004-2013) were reviewed. Patients with radiologically confirmed HC requiring surgery and subsequent development of shunt dependency were identified by cross-linking our prospectively collected tumor database to surgical procedure codes for hydrocephalus treatment (AAF). Patients with preexisting ventriculoperitoneal (VP) shunts (N = 41) were excluded. From 4774 craniotomies performed on 4204 patients, a total of 373 patients (7.8%) with HC preoperatively were identified. Median age was 54.4 years (range 18.1-83.9 years). None were lost to follow-up. Of these, 10.5% (39/373) required permanent CSF shunting due to persisting postoperative HC. The risk of becoming VP shunt dependent in patients with preexisting HC was 7.0% (26/373) within 30 days and 8.9% (33/373) within 90 days. Only secondary (repeat) surgery was a significant risk factor for VP shunt dependency. In this large, contemporary, single-institution consecutive series, 10.5% of intracranial tumor patients with preoperative HC became shunt-dependent post-craniotomy, yielding a surgical cure rate for HC of 89.5%. To the best of our knowledge, this is the first and largest study regarding postoperative shunt dependency after craniotomies for intracranial tumors, and can serve as benchmark for future studies.


Subject(s)
Brain Neoplasms/surgery , Craniotomy/adverse effects , Hydrocephalus/epidemiology , Postoperative Complications/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Hydrocephalus/surgery , Incidence , Male , Middle Aged , Retrospective Studies , Risk Factors , Treatment Outcome , Ventriculoperitoneal Shunt , Young Adult
6.
Sci Rep ; 9(1): 19898, 2019 12 27.
Article in English | MEDLINE | ID: mdl-31882644

ABSTRACT

In a blind, dual-center, multi-observer setting, we here identify the pre-treatment radiologic features by Magnetic Resonance Imaging (MRI) associated with subsequent treatment options in patients with glioma. Study included 220 previously untreated adult patients from two institutions (94 + 126 patients) with a histopathologically confirmed diagnosis of glioma after surgery. Using a blind, cross-institutional and randomized setup, four expert neuroradiologists recorded radiologic features, suggested glioma grade and corresponding confidence. The radiologic features were scored using the Visually AcceSAble Rembrandt Images (VASARI) standard. Results were retrospectively compared to patient treatment outcomes. Our findings show that patients receiving a biopsy or a subtotal resection were more likely to have a tumor with pathological MRI-signal (by T2-weighted Fluid-Attenuated Inversion Recovery) crossing the midline (Hazard Ratio; HR = 1.30 [1.21-1.87], P < 0.001), and those receiving a biopsy sampling more often had multifocal lesions (HR = 1.30 [1.16-1.64], P < 0.001). For low-grade gliomas (N = 50), low observer confidence in the radiographic readings was associated with less chance of a total resection (P = 0.002) and correlated with the use of a more comprehensive adjuvant treatment protocol (Spearman = 0.48, P < 0.001). This study may serve as a guide to the treating physician by identifying the key radiologic determinants most likely to influence the treatment decision-making process.


Subject(s)
Clinical Decision-Making/methods , Glioma/diagnostic imaging , Magnetic Resonance Imaging/methods , Adult , Aged , Aged, 80 and over , Brain Neoplasms/diagnostic imaging , Female , Humans , Male , Middle Aged , Neoplasm Grading/methods , Proportional Hazards Models , Young Adult
7.
Neuroradiology ; 61(5): 545-555, 2019 May.
Article in English | MEDLINE | ID: mdl-30712139

ABSTRACT

PURPOSE: According to the revised World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS) of 2016, oligodendrogliomas are now defined primarily by a specific molecular signature (presence of IDH mutation and 1p19q codeletion). The purpose of our study was to assess the value of dynamic susceptibility contrast MR imaging (DSC-MRI) and diffusion-weighted imaging (DWI) to characterize oligodendrogliomas and to distinguish them from astrocytomas. METHODS: Seventy-one adult patients with untreated WHO grade II and grade III diffuse infiltrating gliomas and known 1p/19q codeletion status were retrospectively identified and analyzed using relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) maps based on whole-tumor volume histograms. The Mann-Whitney U test and logistic regression were used to assess the ability of rCBV and ADC to differentiate between oligodendrogliomas and astrocytomas both independently, but also related to the WHO grade. Prediction performance was evaluated in leave-one-out cross-validation (LOOCV). RESULTS: Oligodendrogliomas showed significantly higher microvascularity (higher rCBVMean ≥ 0.80, p = 0.013) and higher vascular heterogeneity (lower rCBVPeak ≤ 0.044, p = 0.015) than astrocytomas. Diffuse gliomas with higher cellular density (lower ADCMean ≤ 1094 × 10-6 mm2/s, p = 0.009) were more likely to be oligodendrogliomas than astrocytomas. Histogram analysis of rCBV and ADC was able to differentiate between diffuse astrocytomas (WHO grade II) and anaplastic astrocytomas (WHO grade III). CONCLUSION: Histogram-derived rCBV and ADC parameter may be used as biomarkers for identification of oligodendrogliomas and may help characterize diffuse gliomas based upon their genetic characteristics.


Subject(s)
Astrocytoma/diagnostic imaging , Brain Neoplasms/diagnostic imaging , Magnetic Resonance Imaging/methods , Oligodendroglioma/diagnostic imaging , Adult , Aged , Aged, 80 and over , Astrocytoma/genetics , Astrocytoma/pathology , Brain Neoplasms/genetics , Brain Neoplasms/pathology , Codon , Contrast Media , Diagnosis, Differential , Diffusion Magnetic Resonance Imaging , Echo-Planar Imaging , Female , Humans , Male , Middle Aged , Oligodendroglioma/genetics , Oligodendroglioma/pathology , Organometallic Compounds , Polymerase Chain Reaction , Retrospective Studies , Tumor Burden
8.
Microsc Microanal ; 25(2): 462-469, 2019 04.
Article in English | MEDLINE | ID: mdl-30698118

ABSTRACT

Small additions of boron can remarkably improve the long-term creep resistance of 9-12% Cr steels. The improvement has been attributed to boron segregation to grain boundaries during quenching, and subsequent boron incorporation into certain families of precipitates during tempering. However, the detailed mechanisms are not yet fully understood. Atom probe tomography (APT) is an excellent technique for gaining insights into boron distribution, however, in order to acquire accurate analysis of boron in 9-12% Cr steels using APT, there are several key challenges. In order to better understand and address these challenges, we developed a novel method for site-specific APT specimen preparation, which enables convenient preparation of specimens containing specifically selected grain boundaries positioned approximately perpendicular to the axis of the APT tip. Additionally, when analyzing boron at boundaries and in carbides (as diluted solute) and borides, a widening of the profile of boron distribution compared to other elements was repeatedly observed. This phenomenon is particularly analyzed and discussed in light of the evaporation field of different elements. Finally, the possible effects of detector dead-time on quantitative analysis of boron in metal borides are discussed. A simple method using 10B correction was used to obtain good quantification.

9.
Neurosurgery ; 82(3): 365-371, 2018 03 01.
Article in English | MEDLINE | ID: mdl-29992282

ABSTRACT

BACKGROUND: To date, the traditional approach to intraspinal tumors has been open laminectomy or laminoplasty followed by microsurgical tumor resection. Recently, however, minimally invasive approaches have been attempted by some. OBJECTIVE: To investigate the feasibility and safety of minimally invasive surgery (MIS) for primary intradural spinal tumors. METHODS: Medical charts of 83 consecutive patients treated with MIS for intradural spinal tumors were reviewed. Patients were followed up during the study year, 2015, by either routine history/physical examination or by telephone consultation, with a focus on tumor status and surgery-related complications. RESULTS: Mean age at surgery was 53.7 yr and 52% were female. There were 49 schwannomas, 18 meningeomas, 10 ependymomas, 2 hemangioblastomas, 1 neurofibroma, 1 paraganglioma, 1 epidermoid cyst, and 1 hemangiopericytoma. The surgical mortality was 0%. In 87% of cases, gross total resection was achieved. The complication rate was 11%, including 2 cerebrospinal fluid leakages, 1 asymptomatic pseudomeningocele, 2 superficial surgical site infections, 1 sinus vein thrombosis, and 4 cases of neurological deterioration. There were no postoperative hematomas, and no cases of deep vein thrombosis or pulmonary embolism. Ninety-three percent of patients were ambulatory and able to work at the time of follow-up. CONCLUSION: This study both demonstrates that it is feasible and safe to remove select, primary intradural spinal tumors using MIS, and augments the previous literature in favor of MIS for these tumors.


Subject(s)
Minimally Invasive Surgical Procedures/methods , Neurosurgical Procedures/methods , Spinal Cord Neoplasms/diagnostic imaging , Spinal Cord Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Ependymoma/diagnostic imaging , Ependymoma/surgery , Feasibility Studies , Female , Follow-Up Studies , Humans , Laminectomy/adverse effects , Laminectomy/methods , Laminectomy/trends , Laminoplasty/adverse effects , Laminoplasty/methods , Laminoplasty/trends , Male , Middle Aged , Minimally Invasive Surgical Procedures/adverse effects , Minimally Invasive Surgical Procedures/trends , Neurosurgical Procedures/adverse effects , Neurosurgical Procedures/trends , Retrospective Studies , Treatment Outcome
10.
J Comput Assist Tomogr ; 42(5): 807-815, 2018.
Article in English | MEDLINE | ID: mdl-29901512

ABSTRACT

OBJECTIVE: According to the new World Health Organization 2016 classification for tumors of the central nervous system, 1p/19q codeletion defines the genetic hallmark that differentiates oligodendrogliomas from diffuse astrocytomas. The aim of our study was to evaluate whether relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) histogram analysis can stratify survival in adult patients with genetic defined diffuse glioma grades II and III. METHODS: Sixty-seven patients with untreated diffuse gliomas World Health Organization grades II and III and known 1p/19q codeletion status were included retrospectively and analyzed using ADC and rCBV maps based on whole-tumor volume histograms. Overall survival and progression-free survival (PFS) were analyzed by using Kaplan-Meier and Cox survival analyses adjusted for known survival predictors. RESULTS: Significant longer PFS was associated with homogeneous rCBV distribution-higher rCBVpeak (median, 37 vs 26 months; hazard ratio [HR], 3.2; P = 0.02) in patients with astrocytomas, and heterogeneous rCBV distribution-lower rCBVpeak (median, 46 vs 37 months; HR, 5.3; P < 0.001) and higher rCBVmean (median, 44 vs 39 months; HR, 7.9; P = 0.003) in patients with oligodendrogliomas. Apparent diffusion coefficient parameters (ADCpeak, ADCmean) did not stratify PFS and overall survival. CONCLUSIONS: Tumors with heterogeneous perfusion signatures and high average values were associated with longer PFS in patients with oligodendrogliomas. On the contrary, heterogeneous perfusion distribution was associated with poor outcome in patients with diffuse astrocytomas.


Subject(s)
Brain Neoplasms/diagnostic imaging , Diffusion Magnetic Resonance Imaging/methods , Glioma/diagnostic imaging , Adolescent , Adult , Aged , Aged, 80 and over , Brain/diagnostic imaging , Brain/pathology , Brain Neoplasms/pathology , Disease-Free Survival , Female , Glioma/pathology , Humans , Male , Middle Aged , Retrospective Studies , Survival Analysis , Tumor Burden , Young Adult
11.
Neurosurg Rev ; 41(2): 465-472, 2018 Apr.
Article in English | MEDLINE | ID: mdl-28670657

ABSTRACT

The risk of developing a de novo shunt-dependent hydrocephalus (HC) after undergoing a craniotomy for brain tumor in adult patients is largely unknown. All craniotomies for intracranial tumors at Oslo University Hospital in adult patients ≥18 years of age during a 10-year period (2004-2013) were included. None were lost to follow-up. Patients who developed a shunt-dependent HC were identified by cross-linking our prospectively collected tumor database to patients with a NCSP surgical procedure code of hydrocephalus (AAF). Patients with pre-existing HC or ventriculoperitoneal (VP) shunts were excluded from the study. A total of 4401 craniotomies were performed. Of these, 46 patients (1.0%) developed de novo postoperative HC requiring a VP shunt after a median of 93 days (mean 115 days, range 6-442). Median age was 62.0 years (mean 58.9 years, range 27.3-80.9) at time of VP shunt surgery. Patients without pre-existing HC had a 0.2% (n = 8/4401) risk of becoming VP shunt dependent within 30 days and 0.5% (n = 22/4401) within 90 days. Age, sex, tumor location, primary/secondary surgery, and radiotherapy were not associated with VP shunt dependency. Choroid plexus tumors and craniopharyngiomas had increased risk of VP shunt dependency. In this large, contemporary, single-institution consecutive series, the risk of postoperative shunt-dependency after craniotomies for brain tumors without pre-existing HC was very low. This is the largest study with regards to de novo postoperative shunt-dependency after craniotomies for patients with intracranial tumors and can serve as a benchmark for future studies.


Subject(s)
Brain Neoplasms/surgery , Craniotomy/adverse effects , Hydrocephalus/etiology , Hydrocephalus/surgery , Ventriculoperitoneal Shunt , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Male , Middle Aged , Risk Factors , Young Adult
12.
Neuroradiology ; 59(2): 105-126, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28255902

ABSTRACT

Neurologic complications are common after hematopoietic stem cell transplantation (HSCT) and solid organ transplantation (SOT) and affect 30-60% of transplant recipients. The aim of this article is to provide a practical imaging approach based on the timeline and etiology of CNS abnormalities, and neurologic complications related to transplantation of specific organs. The lesions will be classified based upon the interval from HSCT procedure: pre-engraftment period <30 days, early post-engraftment period 30-100 days, late post-engraftment period >100 days, and the interval from SOT procedure: postoperative phase 1-4 weeks, early posttransplant syndromes 1-6 months, late posttransplant syndromes >6 months. Further differentiation will be based on etiology: infections, drug toxicity, metabolic derangements, cerebrovascular complications, and posttransplantation malignancies. In addition, differentiation will be based on complications specific to the type of transplantation: allogeneic and autologous hematopoietic stem cells (HSC), heart, lung, kidney, pancreas, and liver. Thus, in this article we emphasize the strategic role of neuroradiology in the diagnosis and response to treatment by utilizing a methodical approach in the work up of patients with neurologic complications after transplantation.


Subject(s)
Central Nervous System Diseases/diagnostic imaging , Hematopoietic Stem Cell Transplantation , Organ Transplantation , Postoperative Complications/diagnostic imaging , Humans
13.
Acta Neurochir (Wien) ; 159(5): 757-766, 2017 05.
Article in English | MEDLINE | ID: mdl-28281007

ABSTRACT

BACKGROUND: Seizure outcome following surgery in pharmacoresistant temporal lobe epilepsy patients with normal magnetic resonance imaging and normal or non-specific histopathology is not sufficiently presented in the literature. METHODS: In a retrospective design, we reviewed data of 263 patients who had undergone temporal lobe epilepsy surgery and identified 26 (9.9%) who met the inclusion criteria. Seizure outcomes were determined at 2-year follow-up. Potential predictors of Engel class I (satisfactory outcome) were identified by logistic regression analyses. RESULTS: Engel class I outcome was achieved in 61.5% of patients, 50% being completely seizure free (Engel class IA outcome). The strongest predictors of satisfactory outcome were typical ictal seizure semiology (p = 0.048) and localised ictal discharges on scalp EEG (p = 0.036). CONCLUSION: Surgery might be an effective treatment choice for the majority of these patients, although outcomes are less favourable than in patients with magnetic resonance imaging-defined lesional temporal lobe epilepsy. Typical ictal seizure semiology and localised ictal discharges on scalp EEG were predictors of Engel class I outcome.


Subject(s)
Drug Resistant Epilepsy/surgery , Epilepsy, Temporal Lobe/surgery , Outcome Assessment, Health Care/methods , Adolescent , Adult , Drug Resistant Epilepsy/diagnostic imaging , Drug Resistant Epilepsy/pathology , Epilepsy, Temporal Lobe/diagnostic imaging , Epilepsy, Temporal Lobe/pathology , Female , Follow-Up Studies , Humans , Male , Middle Aged , Young Adult
14.
J Cent Nerv Syst Dis ; 8: 1-4, 2016.
Article in English | MEDLINE | ID: mdl-27127413

ABSTRACT

BACKGROUND AND STUDY OBJECT: We report an unusual case of a benign lateral sphenoid wing meningioma that presented with, and was masked by, an acute intracerebral hemorrhage. CASE REPORT: A 68-year-old woman was admitted after sudden onset of coma. Computed tomography (CT) revealed an intracerebral hemorrhage, without any underlying vascular pathology on CT angiography. During the surgery, we found a lateral sphenoid wing meningioma with intratumoral bleeding that extended into the surrounding brain parenchyma. RESULTS: We removed the hematoma and resected the tumor completely in the same session. The histopathological classification of the tumor was a WHO grade I meningothelial meningioma. The patient recovered very well after surgery, without significant neurological sequelae. CONCLUSIONS: Having reviewed the relevant references from the medical literature, we consider this event as an extremely rare presentation of a benign sphenoid wing meningioma in a patient without any predisposing medical factors. The possible mechanisms of bleeding from this tumor type are discussed.

15.
Acta Neurochir (Wien) ; 157(11): 1905-16, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26350516

ABSTRACT

BACKGROUND: The area of predominant perifocal [(18)F]fluorodeoxyglucose ((18)F-FDG) hypometabolism and reduced [(11)C]flumazenil ((11)C-FMZ) -binding on PET scans is currently considered to contain the epileptogenic zone and corresponds anatomically to the area localizing epileptogenicity in patients with temporal lobe epilepsy (TLE). The question is whether the volume of the perifocal pre-operative PET abnormalities, the extent of their resection, and the volume of the non-resected abnormalities affects the post-operative seizure outcome. METHODS: The sample group consisted of 32 patients with mesial temporal sclerosis who underwent anteromedial temporal lobe resection for refractory TLE. All patients had pathologic perifocal findings on both of the PET modalities as well as on the whole-brain MRI. The volumetric data of the PET and MRI abnormalities within the resected temporal lobe were estimated by automated quantitative voxel-based analysis. The obtained volumetric data were investigated in relation to the outcome subgroups of patients (Engel classification) determined at the 2-year post-operative follow-up. RESULTS: The mean volume of the pre-operative perifocal (18)F-FDG- and (11)C-FMZ PET abnormalities in the volumes of interest (VOI) of the epileptogenic temporal lobe, the mean resected volume of these PET abnormalities, the mean volume of the non-resected PET abnormalities, and the mean MRI-derived resected volume were not significantly related to the outcome subgroups and had a low prediction for individual freedom from seizures. CONCLUSIONS: The extent of pre-surgical perifocal PET abnormalities, the extent of their resection, and the extent of non-resected abnormalities were not useful predictors of individual freedom from seizures in patients with TLE.


Subject(s)
Anterior Temporal Lobectomy/adverse effects , Epilepsy, Temporal Lobe/surgery , Positron-Emission Tomography , Seizures/surgery , Temporal Lobe/diagnostic imaging , Adolescent , Adult , Anterior Temporal Lobectomy/methods , Child , Female , Flumazenil , Fluorodeoxyglucose F18 , Humans , Male , Middle Aged , Radiopharmaceuticals , Temporal Lobe/surgery
16.
Neurosurgery ; 77(4): 585-92; discussion 592-3, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26191976

ABSTRACT

BACKGROUND: The existing literature on recurrence rates and long-term clinical outcome after resection of intraspinal nerve sheath tumors is limited. OBJECTIVE: To evaluate progression-free survival, overall survival, and long-term clinical outcome in a consecutive series of 131 patients with symptomatic intraspinal nerve sheath tumors. METHODS: Medical charts were retrospectively reviewed. Surviving patients voluntarily participated in a clinical history and physical examination that focused on neurological function and current tumor status. RESULTS: Follow-up data are 100% complete; median follow-up time was 6.1 years. All patients (100%) had surgery as the first line of treatment; gross total resection was performed in 112 patients (85.5%) and subtotal resection in 19 patients (14.5%). Five-year progression-free survival was 89%. The following risk factors for recurrence were identified: neurofibroma, malignant peripheral nerve sheath tumor, subtotal resection, neurofibromatoses/schwannomatosis, and advancing age at diagnosis. More than 95% of patients had neurological function compatible with an independent life at follow-up. The rate of tumor recurrence in nonneurofibromatosis patients undergoing total resection of a single schwannoma was 3% (3/93), in comparison with a recurrence rate of 32% (12/38) in the remaining patients. CONCLUSION: Gross total resection is the gold standard treatment for patients with intraspinal nerve sheath tumors. In a time of limited health care resources, we recommend that follow-up be focused on the subgroup of patients with a high risk of recurrence. The benefit of long-term, yearly magnetic resonance imaging follow-up with respect to recurrence in nonneurofibromatosis patients undergoing gross total resection of a single schwannoma is, in our opinion, questionable. 1NF2, neurofibromatosis 2NST, nerve sheath tumorOS, overall survivalPFS, progression-free survivalSTR, subtotal resectionWHO, World Health Organization.


Subject(s)
Nerve Sheath Neoplasms/diagnosis , Nerve Sheath Neoplasms/surgery , Spinal Neoplasms/diagnosis , Spinal Neoplasms/surgery , Spinal Nerves/pathology , Spinal Nerves/surgery , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Disease Progression , Disease-Free Survival , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/diagnosis , Neoplasm Recurrence, Local/mortality , Neoplasm Recurrence, Local/surgery , Nerve Sheath Neoplasms/mortality , Prospective Studies , Retrospective Studies , Spinal Neoplasms/mortality , Time Factors , Treatment Outcome , Young Adult
17.
Radiology ; 275(1): 228-34, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25486589

ABSTRACT

PURPOSE: To develop a generic support vector machine (SVM) model by using magnetic resonance (MR) imaging-based blood volume distribution data for preoperative glioma survival associations and to prospectively evaluate the diagnostic effectiveness of this model in autonomous patient data. MATERIALS AND METHODS: Institutional and regional medical ethics committees approved the study, and all patients signed a consent form. Two hundred thirty-five preoperative adult patients from two institutions with a subsequent histologically confirmed diagnosis of glioma after surgery were included retrospectively. An SVM learning technique was applied to MR imaging-based whole-tumor relative cerebral blood volume (rCBV) histograms. SVM models with the highest diagnostic accuracy for 6-month and 1-, 2-, and 3-year survival associations were trained on 101 patients from the first institution. With Cox survival analysis, the diagnostic effectiveness of the SVM models was tested on independent data from 134 patients at the second institution. RESULTS: were adjusted for known survival predictors, including patient age, tumor size, neurologic status, and postsurgery treatment, and were compared with survival associations from an expert reader. RESULTS: Compared with total qualitative assessment by an expert reader, the whole-tumor rCBV-based SVM model was the strongest parameter associated with 6-month and 1-, 2-, and 3-year survival in the independent patient data (area under the receiver operating characteristic curve, 0.794-0.851; hazard ratio, 5.4-21.2). DISCUSSION: Machine learning by means of SVM in combination with whole-tumor rCBV histogram analysis can be used to identify early patient survival in aggressive gliomas. The SVM model returned higher diagnostic accuracy values than an expert reader, and the model appears to be insensitive to patient, observer, and institutional variations.


Subject(s)
Brain Neoplasms/mortality , Brain Neoplasms/pathology , Glioma/mortality , Glioma/pathology , Magnetic Resonance Imaging/methods , Support Vector Machine , Adolescent , Adult , Aged , Aged, 80 and over , Contrast Media , Female , Humans , Image Interpretation, Computer-Assisted , Male , Middle Aged , Retrospective Studies , Survival Analysis
18.
J Magn Reson Imaging ; 40(1): 47-54, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24753371

ABSTRACT

PURPOSE: To retrospectively evaluate the performance of an automatic support vector machine (SVM) routine in combination with perfusion-based dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) for preoperative survival associations in patients with gliomas and compare our results to traditional MRI. MATERIALS AND METHODS: The study was approved by the Ethics Committee and informed consent was signed. Structural, diffusion- and perfusion-weighted MRI was performed at 1.5-T preoperatively in 94 adult patients (49 males, 45 females, 23-82 years; mean 51 years) later diagnosed with a primary glioma. Patients were randomly assigned in training and test datasets and the resulting DSC-based survival associations by SVM were compared to traditional MRI features including contrast-agent enhancement, perfusion- and diffusion-weighted imaging, tumor size, and location. The results were adjusted for age, neurological status, and postoperative factors associated with survival, including surgery and adjuvant therapy. RESULTS: For 1- (26/33 alive, 11/14 deceased), 2- (15/21, 21/26), 3- (12/16, 27/31) and 4- (12/15, 28/32) year survival associations in the test dataset (47 patients), the SVM routine was the only biomarker to consistently associate with survival (Cox; P < 0.001). CONCLUSION: The automatic machine learning routine presented in our study may provide the operator with a reliable instrument for assessing survival in patients with glioma.


Subject(s)
Brain Neoplasms/pathology , Brain Neoplasms/surgery , Glioma/pathology , Glioma/surgery , Magnetic Resonance Angiography/methods , Preoperative Care/methods , Support Vector Machine , Adult , Aged , Aged, 80 and over , Algorithms , Brain Neoplasms/mortality , Female , Glioma/mortality , Humans , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Male , Middle Aged , Prognosis , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity , Survival Rate , Treatment Outcome , Young Adult
19.
Mult Scler ; 20(1): 57-63, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23736535

ABSTRACT

BACKGROUND: Magnetic resonance imaging (MRI) criteria play an important role in making an earlier diagnosis of multiple sclerosis (MS) in patients presenting with clinically isolated syndrome. OBJECTIVE: The objective of this paper is to determine whether MRI criteria may be used to distinguish MS from primary and secondary central nervous system (CNS) vasculitis, lupus, and Sjogren's syndrome. METHODS: MRI criteria were applied retrospectively to images for patients with clinically definite MS (CDMS), primary CNS vasculitis, secondary CNS vasculitis, and autoimmune disorders including systemic lupus erythematosus (SLE) and Sjogren's syndrome. Classical statistics and Bayesian analyses were performed. RESULTS: Overall modified Barkhof's MRI criteria were statistically significant in distinguishing CDMS (60%) from SLE/Sjogren's syndrome (17%, p = 0.0173) but not in distinguishing CDMS from primary CNS vasculitis (50%, p = 0.7376) or secondary CNS vasculitis (58%, p = 1.0000). Four of the five other MRI criteria tested were demonstrated to be superior to modified Barkhof's criteria in predicting MS: nine or more T2 lesions (a component of Barkhof's criteria), one or more ovoid periventricular T2 lesions, one or more perpendicular periventricular T2 lesions, and one or more T2 lesions larger than 6 mm. CONCLUSIONS: MRI criteria, including the modified Barkhof's criteria, were unsuccessful in distinguishing MS from primary CNS vasculitis or secondary CNS vasculitis and mildly successful in distinguishing MS from SLE/Sjogren's syndrome.


Subject(s)
Diagnosis, Differential , Lupus Erythematosus, Systemic/diagnosis , Magnetic Resonance Imaging , Multiple Sclerosis/diagnosis , Sjogren's Syndrome/diagnosis , Vasculitis, Central Nervous System/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Bayes Theorem , Female , Humans , Image Interpretation, Computer-Assisted/methods , Male , Middle Aged , Retrospective Studies , Young Adult
20.
J Bone Oncol ; 3(1): 5-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-26909292

ABSTRACT

AIMS: To evaluate metastatic lesions within the radiation field using repeated magnetic resonance imaging (MRI) and to compare the imaging findings with pain response following radiotherapy (RT) in patients with spinal metastases (SM) from breast cancer. MATERIAL AND METHODS: 32 Patients with SM from breast cancer admitted for fractionated RT were included in this study. MRI examinations of the spine were scored for the extent of bone metastases, epidural disease and the presence and severity of vertebral fractures. Clinical response was defined according to the updated international consensus on palliative RT endpoints. RESULTS: At 2 and 6 months after RT, 38% and 44% of the patients were classified as responders. None of the patients developed motor deficits. Importantly, a decrease in the intraspinal tumor volume after RT was reported in all patients. Only 6% of the patients showed bone metastases progression within the RT field, whereas 60% of the patients showed disease progression outside the RT portals. 5 Patients developed new fractures after RT, and fracture progression was observed in 21 of the 38 lesions (55%). The pain response to RT did not correlate with the presence of vertebral body fracture before RT, fracture progression or other recorded MRI features of metastatic lesions. CONCLUSION: RT provided excellent local tumor control in patients with SM. Most patients benefit from RT even in cases of progressive vertebral fracture. Pain response was not associated with imaging findings and MRI cannot be used to select patients at risk of not responding to RT.

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