1,720,993 research outputs found
A Semi-Unsupervised Segmentation Methodology Based on Texture Recognition for Radiomics: A Preliminary Study on Brain Tumours
Full text linkBecause of the intrinsic anatomic complexity of the brain structures, brain tumors have a high mortality and disability rate, and an early diagnosis is mandatory to contain damages. The commonly used biopsy is the diagnostic gold standard method, but it is invasive and, due to intratumoral heterogeneity, biopsies may lead to an incorrect result. Moreover, some tumors cannot be resectable if located in critical eloquent areas. On the other hand, medical imaging procedures can evaluate the entire tumor in a non-invasive and reproducible way. Radiomics is an emerging diagnosis technique based on quantitative medical image analyses, which makes use of data provided by non-invasive diagnosis techniques such as X-ray, computer-tomography (CT), magnetic resonance (MR), and proton emission tomography (PET). Radiomics techniques require the comprehensive analysis of huge numbers of medical images to extract a large and useful number of phenotypic features (usually called radiomics biomarkers). The goal is to explore and obtain the associations between features of tumors, diagnosis and patients’ prognoses to choose the best treatments and maximize the patient’s survival rate. Current radiomics techniques are not standardized in term of segmentation, feature extraction, and selection, moreover, the decision on suitable therapies still requires the supervision of an expert doctor. In this paper, we propose a semi-automatic methodology aimed to help the identification and segmentation of malignant tissues by using the combination of binary texture recognition, growing area algorithm, and machine learning techniques. In particular, the proposed method not only helps to better identify pathologic tissues but also permits to analyze in a fast way the huge amount of data, in Dicom format, provided by non-invasive diagnostic techniques. A preliminary experimental assessment has been conducted, considering a real MRI database of brain tumors. The method has been compared with the segmentation software’s tools “slicer 3D”. The obtained results are quite promising and demonstrate the potentialities of the proposed semi-unsupervised segmentation methodology
Imaging of inner ear malformations: a primer for radiologists
Full text linkIn the multidisciplinary management of patients with inner ear malformations (IEMs), the correct diagnosis makes the differences in terms of clinical and surgical treatment. The complex anatomical landscape of the inner ear, comprising several small structures, makes imaging of this region particularly challenging for general radiologists. Imaging techniques are important for identifying the presence and defining the type of IEM and the cochlear nerve condition. High-resolution magnetic resonance imaging (MRI) sequences and high-resolution computed tomography (HRCT) are the mainstay imaging techniques in this area. Dedicated MRI and HRCT protocols play an important role in the diagnosis and treatment of patients with inner ear disease. The most suitable technique should be selected depending on the clinical setting. However, in cases of congenital malformation of the inner ear, these techniques should be considered complementary. Since prompt intervention has a positive impact on the treatment outcomes, early diagnosis of IEMs is very important in the management of deaf patients. This article reviews the key concepts of IEMs for clinical radiologists by focusing on recent literature updates, discusses the principal imaging findings and clinical implications for every IEM subgroup, thus providing a practical diagnostic approach
ADC maps in non invasive characterization of IDH mutation status in high grade glioma
No full textIntroduction The new brain tumor classification (2016 WHO) distinguishes diffuse glioma based on their molecular characteristics of isocitrate dehydroge- nase (IDH) in IDH-mutant, IDH-wild type and IDH NOS (not otherwise specified). The evaluation of IDH mutation status has diagnostic, prog- nostic and therapeutic implications. The aim of this study was to evaluate whether the analysis of ADC maps can non-invasively predict the IDH mutation status. Materials Conventional MR images and ADC maps of 28 patients (11-F, 17-M) with histological confirmed diffuse high-grade glioma (WHO-grade III- IV) were reviewed and correlated with the IDH mutation status (18-MUT, 10-WT). MRI was performed on a 1.5T MR scan (GE-Optima 450). In order to place the ROIs on the solid components of the lesion, the ADC maps were elaborated and co-registered with the T2-w and Gd-enhanced T1-w images. For each tumor 4-5 ROIs were placed and the mean ADC- values (ADCmean) were calculated, choosing the lowest values for each patient. The comparison of the ADCmean values between IDH-MUT and IDH-WT was performed using the Student's "t" test, considering signifi- cant a value of p <0.05. Results The ADCmean values in IDH-WT patients (0.86x10-3mm2/s +/- 0.06) were lower than those of IDH-MUT patients (1.24x10-3mm2 /s +/- 0.19) and the difference between both groups was statistically significant (p <0.01). The value of ADC ≥ 1.01 x10-3mm2/s can be considered as a "cut-off" value to differentiate the IDH mutation status. Conclusions Adding quantitative data such as evaluation of ADC-values to conven- tional MR imaging can be used as a non-invasive marker of specific molecular patterns
Conventional MRI-Derived Biomarkers of Adult-Type Diffuse Glioma Molecular Subtypes: A Comprehensive Review
Full text linkThe introduction of molecular criteria into the classification of diffuse gliomas has added interesting practical implications to glioma management. This has created a new clinical need for correlating imaging characteristics with glioma genotypes, also known as radiogenomics or imaging genomics. Although many studies have primarily focused on the use of advanced magnetic resonance imaging (MRI) techniques for radiogenomics purposes, conventional MRI sequences remain the reference point in the study and characterization of brain tumors. A summary of the conventional imaging features of glioma molecular subtypes should be useful as a tool for daily diagnostic brain tumor management. Hence, this article aims to summarize the conventional MRI features of glioma molecular subtypes in light of the recent literature
IMAGING OF VESTIBULAR SCHWANNOMA
No full textLesions of the cerebellopontine angle and internal auditory canal are a frequent finding in neuroradiological examinations and their detection may represent a diagnostic challenge. Among these lesions, vestibular
schwannomas and meningiomas are certainly the most frequent and account for up to 90% of all cerebellopontine angle tumours. The remaining ones are a group of lesions arising from the different structures found in these anatomical regions such as haemangiomas, lipomas, lymphomas, facial nerve tumours, and aneurysms. This chapter will introduce this topic focusing on a practical coverage of the typical and atypical neuroradiological signs that will drive towards the most correct differential diagnosis checklist. High-quality neuroradiological images will support the reader for an optimal learning experience
Utilizzo delle mappe ADC nella valutazione non invasiva dello stato di mutazione dell’IDH in gliomi di alto grado.
No full textTesto dell'abstract Scopo La nuova classificazione dei tumori cerebrali (2016 WHO) distingue i gliomi diffusi in base alle caratteristiche molecolari dell’isocitrato deidrogenasi (IDH) in IDH mutati, IDH wild type e non altrimenti specificati. La valutazione dello stato di mutazione dell’IDH ha implicazioni diagnostiche, prognostiche e terapeutiche. Lo scopo di questo studio è valutare se l’analisi quantitativa delle mappe ADC possa predire in modo non invasivo lo stato di mutazione dell’IDH. Materiale e metodi Sono state esaminate retrospettivamente RM e mappe ADC di 28 pazienti (11 F, 17 M) con diagnosi istologica di glioma diffuso di alto grado (G-III, G-IV WHO) e valutazione dello stato di mutazione dell’IDH1 (18 MUT, 10 WT). Gli esami sono stati condotti su apparecchio RM 1,5 T. Le mappe ADC sono state elaborate e co-registrate con le immagini T2w e T1 post mdc in modo da posizionare le ROI sulle componenti solide della lesione, evitando le componenti emorragica, cistica o necrotica. Sono state posizionate 4-5 ROI per ogni tumore e calcolati i valori medi di ADC (ADCmean) scegliendo tra i valori più bassi per ogni Paziente. La comparazione dei valori ADCmean tra IDH-MUT e IDH-WT è stata condotta utilizzando il “t” test di Student, considerando statisticamente significativo un valore di p<0. Risultati I valori ADCmean nei pazienti IDH-WT (0,86x10-3mm2 /s)(+/- 0,06) sono risultati più bassi rispetto a quelli dei pazienti IDH-MUT (1,24x10-3mm2 /s)(+/- 0,19) con differenza tra i due gruppi significativa per p<0,01. Il valore minimo di ADC =1,01 x10-3mm2 /s può essere considerato come“cut-off “per differenziare lo stato di mutazione. Conclusioni L’aggiunta di dati quantitativi come la valutazione dell’ADC all’imaging RM convenzionale potrebbe essere utilizzata di routine come marker non-invasivo di pattern molecolari specifici
Computed tomography and magnetic resonance imaging findings in ophthalmoplegic migraine.
No full textClinical and brain imaging findings in a child with vitamin B12 deficiency
Full text linkVitamin B12 (Vit-B12) deficiency is a rare and treatable cause of failure to thrive and delayed development in infants who are exclusively breastfed. Apart from genetic causes, it can be related to a malabsorption syndrome or when the mother follows a strict vegetarian or vegan diet, causing a low hepatic storage of Vit-B12 in the infant at birth. As the neurological symptoms are nonspecific, a brain magnetic resonance imaging (MRI) exam is usually performed to rule out primary causes of neurodevelopmental delay. Findings related to brain atrophy are usually observed. A favorable response is achieved with Vit-B12 therapy, and neurological symptoms dramatically improve within a few days after the treatment. We present the case of an infant with severe Vit-B12 deficiency, exclusively breastfed by his young vegan mother, and whose clinical symptoms together with MRI findings improved after treatment. Brain atrophy recovery after Vit-B12 therapy has been seldom documented
- …
