An accessible deep learning tool for voxel-wise classification of brain malignancies from perfusion MRI

Noninvasive differential diagnosis of brain tumors is currently based on the assessment of magnetic resonance imaging (MRI) coupled with dynamic susceptibility contrast (DSC). However, a definitive diagnosis often requires neurosurgical interventions that compromise patients' quality of life. We apply deep learning on DSC images from histology-confirmed patients with glioblastoma, metastasis, or lymphoma. The convolutional neural network trained on ∼50,000 voxels from 40 patients provides intratumor probability maps that yield clinical-grade diagnosis. Performance is tested in 400 additional cases and an external validation cohort of 128 patients. The tool reaches a three-way accuracy of 0.78, superior to the conventional MRI metrics cerebral blood volume (0.55) and percentage of signal recovery (0.59), showing high value as a support diagnostic tool. Our open-access software, Diagnosis In Susceptibility Contrast Enhancing Regions for Neuro-oncology (DISCERN), demonstrates its potential in aiding medical decisions for brain tumor diagnosis using standard-of-care MRI.

Cognitive and brain connectivity trajectories in critically ill COVID-19 patients

BACKGROUND

Multiple Organ failure (MOF) is one of the main causes of admission to the Intensive Care Unit (ICU) of patients infected with COVID-19 and can cause short- and long-term neurological deficits.

OBJECTIVE

To compare the cognitive functioning and functional brain connectivity at 6-12 months after discharge in two groups of individuals with MOF, one due to COVID-19 and the other due to another cause (MOF-group), with a group of Healthy Controls (HC).

METHODS

Thirty-six participants, 12 from each group, underwent a neuropsychological and neuroimaging assessment at both time-points. Functional connectivity of the resting state networks was compared between COVID-19 and HC while controlling for the effect of MOF. The association between functional connectivity and neuropsychological performance was also investigated.

RESULTS

Compared to the HC, COVID-19 group demonstrated hypoconnectivity between the Default Mode Network and Salience Network. This pattern was associated with worse performance on tests of attention and information processing speed, at both time-points.

CONCLUSION

The study of the association between cognitive function and brain functional connectivity in COVID-19 allows the understanding of the short- and long-term neurological alterations of this disease and promotes the development of intervention programs to improve the quality of life for this understudied population.

Analyzing structural and functional brain changes related to an integrative cognitive remediation program for schizophrenia: A randomized controlled trial

Cognitive remediation has been shown to improve cognition in schizophrenia, but little is known about the specific functional and structural brain changes related to the implementation of an integrative cognitive remediation program. This study analyzed the functional and structural brain changes identified after implementing an integrative cognitive remediation program, REHACOP, in schizophrenia. The program combined cognitive remediation, social cognitive training, and functional and social skills training. The sample included 59 patients that were assigned to either the REHACOP group or an active control group for 20 weeks. In addition to a clinical and neuropsychological assessment, T1-weighted, diffusion-weighted and functional magnetic resonance images were acquired during a resting-state and during a memory paradigm, both at baseline and follow-up. Voxel-based morphometry, tract-based spatial statistics, resting-state functional connectivity, and brain activation analyses during the memory paradigm were performed. Brain changes were assessed with a 2 × 2 repeated-measure analysis of covariance for group x time interaction. Intragroup paired t-tests were also carried out. Repeated-measure analyses revealed improvements in cognition and functional outcome, but no significant brain changes associated with the integrative cognitive remediation program. Intragroup analyses showed greater gray matter volume and cortical thickness in right temporal regions at post-treatment in the REHACOP group. The absence of significant brain-level results associated with cognitive remediation may be partly due to the small sample size, which limited the statistical power of the study. Therefore, further research is needed to clarify whether the temporal lobe may be a key area involved in cognitive improvements following cognitive remediation.

Multimodal visual system analysis as a biomarker of visual hallucinations in Parkinson's disease

Visual hallucinations (VH) are present in up to 75% of Parkinson's disease (PD) patients. However, their neural bases and participation of the visual system in VH are not well-understood in PD. Seventy-four participants, 12 PD with VH (PDVH), 35 PD without VH (PDnoVH) and 27 controls underwent a battery of primary visual function and visual cognition tests, retinal optical coherence tomography and structural and resting-state functional brain MRI. We quantified cortical thickness with Freesurfer and functional connectivity (FC) of Visual (VIS), Fronto-Parietal (FP), Ventral Attention (VAN) and Dorsal Attention (DAN) networks with CONN toolbox. Group comparisons were performed with MANCOVA. Area Under the Curve (AUC) was computed to assess the ability of visual variables to differentiate PDVH and PDnoVH. There were no significant PDVH vs PDnoVH differences in disease duration, motor manifestations, general cognition or dopamine agonist therapy (DA) use. Compared to PDnoVH and HC, and regardless of DA use, PDVH showed significantly reduced contrast sensitivity, visuoperceptive and visuospatial abilities, increased retina photoreceptor layer thickness, reduced cortical thickness mostly in right visual associative areas, decreased between-network VIS-VAN and VAN-DAN connectivity and increased within-network DAN connectivity. The combination of clinical and imaging variables that best discriminated PDVH and PDnoVH (highest AUC), where within-network DAN FC, photoreceptor layer thickness and cube analysis test from Visual Object and Space Perception Battery (accuracy of 81.8%). Compared to PDnoVH, PDVH have specific functional and structural abnormalities within the visual system, which can be quantified non-invasively and could potentially constitute biomarkers for VH in PD.

Contributions of sex, depression, and cognition on brain connectivity dynamics in Parkinson's disease

Alterations in time-varying functional connectivity (FC) have been found in Parkinson's disease (PD) patients. To date, very little is known about the influence of sex on brain FC in PD patients and how this could be related to disease severity. The first objective was to evaluate the influence of sex on dynamic FC characteristics in PD patients and healthy controls (HC), while the second aim was to investigate the temporal patterns of dynamic connectivity related to PD motor and non-motor symptoms. Ninety-nine PD patients and sixty-two HC underwent a neuropsychological and clinical assessment. Rs-fMRI and T1-weighted MRI were also acquired. Dynamic FC analyses were performed in the GIFT toolbox. Dynamic FC analyses identified two States: State I, characterized by within-network positive coupling; and State II that showed between-network connectivity, mostly involving somatomotor and visual networks. Sex differences were found in dynamic indexes in HC but these differences were not observed in PD. Hierarchical clustering analysis identified three phenotypically distinct PD subgroups: (1) Subgroup A was characterized by mild motor symptoms; (2) Subgroup B was characterized by depressive and motor symptoms; (3) Subgroup C was characterized by cognitive and motor symptoms. Results revealed that changes in the temporal properties of connectivity were related to the motor/non-motor outcomes of PD severity. Findings suggest that while in HC sex differences may play a certain role in dynamic connectivity patterns, in PD patients, these effects may be overcome by the neurodegenerative process. Changes in the temporal properties of connectivity in PD were mainly related to the clinical markers of PD severity.

Advanced MRI assessment of non-enhancing peritumoral signal abnormality in brain lesions

Evaluation of Central Nervous System (CNS) focal lesions has been classically made focusing on the assessment solid or enhancing component. However, the assessment of solitary peripherally enhancing lesions where the differential diagnosis includes High-Grade Gliomas (HGG) and metastasis, is usually challenging. Several studies have tried to address the characteristics of peritumoral non-enhancing areas, for better characterization of these lesions. Peritumoral hyperintense T2/FLAIR signal abnormality predominantly contains infiltrating tumor cells in HGG whereas CNS metastasis induce pure vasogenic edema. In addition, the accurate determination of the real extension of HGG is critical for treatment selection and outcome. Conventional MRI sequences are limited in distinguishing infiltrating neoplasm from vasogenic edema. Advanced MRI sequences like Diffusion Weighted Imaging (DWI), Diffusion Tensor Imaging (DTI), Perfusion Weighted Imaging (PWI) and MR spectroscopy (MRS) have all been utilized for this aim with acceptable results. Other advanced MRI approaches, less explored for this task such as Arterial Spin Labelling (ASL), Diffusion Kurtosis Imaging (DKI), T2 relaxometry or Amide Proton Transfer (APT) are also showning promising results in this scenario. In this article, we will discuss the physiopathological basis of peritumoral T2/FLAIR signal abnormality and review potential applications of advanced MRI sequences for its evaluation.

Conventional and advanced MRI evaluation of brain vascular malformations

Vascular malformations (VMs) of the central nervous system (CNS) include a wide range of pathological conditions related to intra and extracranial vessel abnormalities. Although some VMs show typical neuroimaging features, other VMs share and overlap pathological and neuroimaging features that hinder an accurate differentiation between them. Hence, it is not uncommon to misclassify different types of VMs under the general heading of arteriovenous malformations. Thorough knowledge of the imaging findings of each type of VM is mandatory to avoid these inaccuracies. Conventional MRI sequences, including MR angiography, have allowed the evaluation of CNS VMs without using ionizing radiation. Newer MRI techniques, such as susceptibility-weighted imaging, black blood sequences, arterial spin labeling, and 4D flow imaging, have an added value of providing physiopathological data in real time regarding the hemodynamics of VMs. Beyond MR images, new insights using 3D printed models are being incorporated as part of the armamentarium for a noninvasive evaluation of VMs. In this paper, we briefly review the pathophysiology of CNS VMs, focusing on the MRI findings that may be helpful to differentiate them. We discuss the role of each conventional and advanced MRI sequence for VMs assessment and provide some insights about the value of structured reports of 3D printing to evaluate VMs.

Brain White Matter Correlates of Creativity in Schizophrenia: A Diffusion Tensor Imaging Study

The relationship between creativity and psychopathology has been a controversial research topic for decades. Specifically, it has been shown that people with schizophrenia have an impairment in creative performance. However, little is known about the brain correlates underlying this impairment. Therefore, the aim of this study was to analyze whole brain white matter (WM) correlates of several creativity dimensions in people with schizophrenia. Fifty-five patients with schizophrenia underwent diffusion-weighted imaging on a 3T magnetic resonance imaging machine as well as a clinical and a creativity assessment, including verbal and figural creativity measures. Tract-based spatial statistic, implemented in FMRIB Software Library (FSL), was used to assess whole brain WM correlates with different creativity dimensions, controlling for sex, age, premorbid IQ, and medication. Mean fractional anisotropy (FA) in frontal, temporal, subcortical, brain stem, and interhemispheric regions correlated positively with figural originality. The most significant clusters included the right corticospinal tract (cerebral peduncle part) and the right body of the corpus callosum. Verbal creativity did not show any significant correlation. As a whole, these findings suggest that widespread WM integrity is involved in creative performance of patients with schizophrenia. Many of these areas have also been related to creativity in healthy people. In addition, some of these regions have shown to be particularly impaired in schizophrenia, suggesting that these WM alterations could be underlying the worse creative performance found in this pathology.

Metastatic Versus Osteoporotic Vertebral Fractures on MRI: A Blinded, Multicenter, and Multispecialty Observer Agreement Evaluation

BACKGROUND

MRI is assumed to be valid for distinguishing metastatic vertebral fractures (MVFs) from osteoporotic vertebral fractures (OVFs). This study assessed (1) concordance between the image-based diagnosis of MVF versus OVF and the reference (biopsy or follow-up of >6 months), (2) interobserver and intraobserver agreement on key imaging findings and the diagnosis of MVF versus OVF, and (3) whether disclosing a patient's history of cancer leads to variations in diagnosis, concordance, or agreement.

PATIENTS AND METHODS

This retrospective cohort study included clinical data and imaging from 203 patients with confirmed MVF or OVF provided to 25 clinicians (neurosurgeons, radiologists, orthopedic surgeons, and radiation oncologists). From January 2018 through October 2018, the clinicians interpreted images in conditions as close as possible to routine practice. Each specialist assessed data twice, with a minimum 6-week interval, blinded to assessments made by other clinicians and to their own previous assessments. The kappa statistic was used to assess interobserver and intraobserver agreement on key imaging findings, diagnosis (MVF vs OVF), and concordance with the reference. Subgroup analyses were based on clinicians' specialty, years of experience, and complexity of the hospital where they worked.

RESULTS

For diagnosis of MVF versus OVF, interobserver agreement was fair, whereas intraobserver agreement was substantial. Only the latter improved to almost perfect when a patient's history of cancer was disclosed. Interobserver agreement for key imaging findings was fair or moderate, whereas intraobserver agreement on key imaging findings was moderate or substantial. Concordance between the diagnosis of MVF versus OVF and the reference was moderate. Results were similar regardless of clinicians' specialty, experience, and hospital category.

CONCLUSIONS

When MRI is used to distinguish MVF versus OVF, interobserver agreement and concordance with the reference were moderate. These results cast doubt on the reliability of basing such a diagnosis on MRI in routine practice.

Brain connectivity and cognitive functioning in individuals six months after multiorgan failure

Multiorgan failure (MOF) is a life-threating condition that affects two or more systems of organs not involved in the disorder that motivates admission to an Intensive Care Unit (ICU). Patients who survive MOF frequently present long-term functional, neurological, cognitive, and psychiatric sequelae. However, the changes to the brain that explain such symptoms remain unclear.

OBJECTIVE

To determine brain connectivity and cognitive functioning differences between a group of MOF patients six months after ICU discharge and healthy controls (HC).

METHODS

22 MOF patients and 22 HC matched by age, sex, and years of education were recruited. Both groups were administered a 3T magnetic resonance imaging (MRI), including structural T1 and functional BOLD, as well as a comprehensive neuropsychological evaluation that included tests of learning and memory, speed of information processing and attention, executive function, visual constructional abilities, and language. Voxel-based morphometry was used to analyses T1 images. For the functional data at rest, functional connectivity (FC) analyses were performed.

RESULTS

There were no significant differences in structural imaging and neuropsychological performance between groups, even though patients with MOF performed worse in all the cognitive tests. Functional neuroimaging in the default mode network (DMN) showed hyper-connectivity towards sensory-motor, cerebellum, and visual networks. DMN connectivity had a significant association with the severity of MOF during ICU stay and with the neuropsychological scores in tests of attention and visual constructional abilities.

CONCLUSIONS

In MOF patients without structural brain injury, DMN connectivity six months after ICU discharge is associated with MOF severity and neuropsychological impairment, which supports the use of resting-state functional MRI as a potential tool to predict the onset of long-term cognitive deficits in these patients. Similar to what occurs at the onset of other pathologies, the observed hyper-connectivity might suggest network re-adaptation following MOF.

Dynamic functional connectivity in Parkinson's disease patients with mild cognitive impairment and normal cognition

The objective was to assess dynamic functional connectivity (FC) and local/global connectivity in Parkinson's disease (PD) patients with mild cognitive impairment (PD-MCI) and with normal cognition (PD-NC). The sample included 35 PD patients and 26 healthy controls (HC). Cognitive assessment followed an extensive neuropsychological battery. For resting-state functional MRI (rs-fMRI) analysis, independent component analysis (ICA) was performed and components were located in 7 networks: Subcortical (SC), Auditory (AUD), Somatomotor (SM), visual (VI), cognitive-control (CC), default-mode (DMN), and cerebellar (CB). Dynamic FC analysis was performed using the GIFT toolbox. FC differences between groups in each FC state were analysed with the network-based statistic (NBS) approach. Finally, a graph-theoretical analysis for local/global parameters was performed. The whole sample showed 2 dynamic FC states during the rs-fMRI. PD-MCI patients showed decreased mean dwell time in the hypo-connectivity state (p = 0.030) and showed increased number of state transitions (p = 0.007) compared with the HC. In addition, in the hypo-connectivity state, PD-MCI patients showed reduced inter-network FC between the SM-CC, SM-VI, SM-AUD, CC-VI and SC-DMN compared with the HC (p < 0.05-FDR). These FC alterations in PD-MCI were accompanied by graph-topological alterations in nodes located in the SM network (p < 0.001). In contrast, no differences were found between the PD-NC and HC. Findings suggest the presence of dynamic functional brain deteriorations in PD-MCI that are not present in PD-NC, showing the PD-MCI group dynamic FC dysfunctions, reduced FC mostly between SM-CC networks and graph-topological deteriorations in the SM network. A dynamic FC approach could be helpful to understand cognitive deterioration in PD.

Increased brain connectivity and activation after cognitive rehabilitation in Parkinson's disease: a randomized controlled trial

Cognitive rehabilitation programs have demonstrated efficacy in improving cognitive functions in Parkinson's disease (PD), but little is known about cerebral changes associated with an integrative cognitive rehabilitation in PD. To assess structural and functional cerebral changes in PD patients, after attending a three-month integrative cognitive rehabilitation program (REHACOP). Forty-four PD patients were randomly divided into REHACOP group (cognitive rehabilitation) and a control group (occupational therapy). T1-weighted, diffusion weighted and functional magnetic resonance images (fMRI) during resting-state and during a memory paradigm (with learning and recognition tasks) were acquired at pre-treatment and post-treatment. Cerebral changes were assessed with repeated measures ANOVA 2 × 2 for group x time interaction. During resting-state fMRI, the REHACOP group showed significantly increased brain connectivity between the left inferior temporal lobe and the bilateral dorsolateral prefrontal cortex compared to the control group. Moreover, during the recognition fMRI task, the REHACOP group showed significantly increased brain activation in the left middle temporal area compared to the control group. During the learning fMRI task, the REHACOP group showed increased brain activation in the left inferior frontal lobe at post-treatment compared to pre-treatment. No significant structural changes were found between pre- and post-treatment. Finally, the REHACOP group showed significant and positive correlations between the brain connectivity and activation and the cognitive performance at post-treatment. This randomized controlled trial suggests that an integrative cognitive rehabilitation program can produce significant functional cerebral changes in PD patients and adds evidence to the efficacy of cognitive rehabilitation programs in the therapeutic approach for PD.

Verbal Memory in Parkinson's Disease: A Combined DTI and fMRI Study

Background:

While significant progress has been made to determine the functional role of specific gray matter areas underlying verbal memory in Parkinson’s disease (PD), very little is known about the relationship between these regions and their underlying white matter structures.

Objective:

The objectives of this study were (1) to investigate verbal memory, fractional anisotropy and brain activation differences between PD patients and healthy controls (HC), (2) to explore the neuroanatomical and neurofunctional correlates of verbal memory in PD, and (3) to investigate the relationship between these neuroanatomical and neurofunctional verbal memory correlates in PD.

Methods:

Functional magnetic resonance imaging (fMRI) while performing a verbal memory paradigm and diffusion tensor imaging data (DTI), were acquired in 37 PD patients and 15 age-, sex-, and education-matched HC.

Results:

PD patients showed verbal recognition memory impairment, lower fractional anisotropy in the anterior cingulate tract, and lower brain activation in the inferior orbitofrontal cortex compared to HC. Brain activation in the inferior orbitofrontal cortex correlated significantly with verbal recognition memory impairment in PD patients. In addition, a relationship between brain activation in the inferior orbitofrontal cortex and fractional anisotropy of the uncinate fasciculus was found in PD.

Conclusions:

These results reveal that deficits in verbal memory in PD are accompanied by functional brain activation changes, but also have specific structural correlates related to white matter microstructural integrity.

Altered functional connectivity in the default mode network is associated with cognitive impairment and brain anatomical changes in Parkinson's disease

OBJECTIVE

To assess whether functional neural connectivity is disrupted between the regions of the default mode network (DMN) in Parkinson's disease (PD) and how this connectivity is related to cognition, brain gray matter structure and white matter integrity and diffusivity.

METHODS

Thirty-seven PD patients and 16 healthy controls were evaluated, using resting-state functional magnetic resonance imaging (MRI), T1-weighted MRI, diffusion-weighted imaging and a battery of cognitive tests. Functional connectivity between the regions of the DMN, specifically in the precuneus, anterior and posterior cingulate, medial prefrontal and temporal and inferior parietal cortices was assessed with seed-to-voxel connectivity; gray matter volume and white matter values were determined using voxel-based morphometry and tract-based spatial statistics.

RESULTS

Reduced functional connectivity was observed between the posterior cingulate and medial temporal lobe in PD. Lower cognitive performance, gray matter loss in posterior, medial temporal and parietal areas, and fractional anisotropy reduction in the white matter adjacent to DMN regions were also observed in PD patients compared with healthy controls. Lower DMN functional connectivity correlated with lower verbal and visual memory and visual abilities performance in PD. In addition, lower DMN functional connectivity correlated with lower gray matter volume in the posterior cingulate and precuneus, and with lower white matter fractional anisotropy of the inferior longitudinal and posterior cingulate fasciculi in PD.

CONCLUSIONS

By combining different neuroimaging techniques and cognitive data, results showed that functional connectivity alteration between the regions of the DMN is associated with lower cognitive performance and gray and white matter abnormalities in PD.

Neuroanatomical Correlates of Theory of Mind Deficit in Parkinson's Disease: A Multimodal Imaging Study

BACKGROUND

Parkinson's disease (PD) patients show theory of mind (ToM) deficit since the early stages of the disease, and this deficit has been associated with working memory, executive functions and quality of life impairment. To date, neuroanatomical correlates of ToM have not been assessed with magnetic resonance imaging in PD. The main objective of this study was to assess cerebral correlates of ToM deficit in PD. The second objective was to explore the relationships between ToM, working memory and executive functions, and to analyse the neural correlates of ToM, controlling for both working memory and executive functions.

METHODS

Thirty-seven PD patients (Hoehn and Yahr median = 2.0) and 15 healthy controls underwent a neuropsychological assessment and magnetic resonance images in a 3T-scanner were acquired. T1-weighted images were analysed with voxel-based morphometry, and white matter integrity and diffusivity measures were obtained from diffusion weighted images and analysed using tract-based spatial statistics.

RESULTS

PD patients showed impairments in ToM, working memory and executive functions; grey matter loss and white matter reduction compared to healthy controls. Grey matter volume decrease in the precentral and postcentral gyrus, middle and inferior frontal gyrus correlated with ToM deficit in PD. White matter in the superior longitudinal fasciculus (adjacent to the parietal lobe) and white matter adjacent to the frontal lobe correlated with ToM impairment in PD. After controlling for executive functions, the relationship between ToM deficit and white matter remained significant for white matter areas adjacent to the precuneus and the parietal lobe.

CONCLUSIONS

Findings reinforce the existence of ToM impairment from the early Hoehn and Yahr stages in PD, and the findings suggest associations with white matter and grey matter volume decrease. This study contributes to better understand ToM deficit and its neural correlates in PD, which is a basic skill for development of healthy social relationships.

[Indication of magnetic resonance imaging in cases of headaches in adults: results following the RAND/UCLA appropriateness method]

INTRODUCTION. The number of requests for magnetic resonance imaging (MRI) scans in healthcare systems is continually on the rise. An MRI scan of the head is one of the most frequent locations, which if used inappropriately entails a loss of resources. Consequently, guidelines are needed to help the physician make decisions and allow better management of resources. AIM. To establish the key indications of MRI scans in cases of adults with headache. MATERIALS AND METHODS. The RAND/UCLA appropriateness method was used, that is, following a systematic review, a list of possible indications of MRI in cases of headache was drawn up. This list was then assessed by a panel of experts and given a score between 1 ('totally inappropriate') and 9 ('totally appropriate'). An initial round of scoring was carried out online, the results were then discussed at a face-to-face meeting of the experts and finally another online round was undertaken. MRI was considered appropriate in each indication if the mean score was 6.5 or higher and there was agreement among the experts (using the IPRAS index). RESULTS. MRI scanning was considered appropriate in cases of: new headache, new headache in immunodeficient patients, sudden intense headache, headache with focal neurological symptoms, postural headache, headache due to physical effort or Valsalva manoeuvres, suspected thrombosis in the venous sinuses, systemic involvement, progressive headache, headache in pregnancy, autonomic trigeminal headache or severe cranial traumatic injury with focus. CONCLUSIONS. It seems that indication can be summed up in headaches with a suspected secondary pathology. The methodology employed makes it possible to establish MRI indications that can be useful both in clinical practice and for healthcare management practitioners.

[Magnetic resonance imaging in long-term assessment after surgery for aortic coarctation]

OBJECTIVES

Spin echo or gradient echo magnetic resonance imaging provides enough information to plan patient management and can be completed with the use of three-dimensional magnetic resonance angiography to evaluate the need for reintervention, assess follow-up, or discharge the patient.

PATIENTS AND METHODS

From 1990-2003, we evaluated 101 patients after initial corrective surgery for aortic coarctation at the age of 3.1 +/- 3 years, with subsequent postoperative assessment at 1 year and again 12.4 +/- 4.2 years later. No mortality was registered during the follow-up. Corrective surgery was performed in 32 patients (31.6 %) before the first month of life. All the patients were evaluated with spin-echo and echo gradient and 34 were evaluated with magnetic resonance angiography. The patients were classified into two groups: group A consisted of 68 patients (11 < 1 month old) with no complications. End-to-end anastomosis was performed in 55, the Alvarez technique in five, the Waldhausen technique in six, and conduit in two. Group B consisted of 33 patients complicated with early aortic recoarctation (21 corrected before the age of 1 month). End-to-end anastomosis was performed in 29, the Alvarez technique in two, and grafting in two. During the follow-up, 43 reinterventions were performed. Isthmus diameter/descending aorta diameter at the diaphragmatic level and repaired site diameter/descending aorta diameter at the diaphragmatic level were measured.

RESULTS

Group A: the isthmus diameter/descending aorta diameter at the diaphragmatic level index was 0.92 +/- 0.08 and the repaired site diameter/ descending aorta diameter at diaphragmatic level index was 0.90 +/- 0.05. Twenty-three patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed two late stenosis (one in a 10-year-old patient with an end-to-end anastomosis performed previously, and another in an 18-year-old patient with a proximal and distal obstructed conduit). Group B: the isthmus diameter/descending aorta diameter index was 0.84 +/- 0.1 and the repaired site diameter/ descending aorta diameter index was 0.82 +/- 0.11. Eleven patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed five stenosis indexes (0.53-0.73) surgically corrected before the age of 2 months, four with an initial technique based on end-to-end anastomosis and one with a graft.

CONCLUSIONS

Our results support the influence of young age, the use of end-to-end anastomosis and grafts in recoarctation and their late influence on recurrent recoarctation. The patients in group A were discharged in childhood or adulthood after periodic follow-up every 5 years with magnetic resonance angiography for 18 years with results within the normal range, while patients in group B required longer follow-up.

[Low grade astroblastoma: pathological and magnetic resonance findings]

INTRODUCTION

The astroblastoma is an uncommon type of glial tumour. It accounts for less than 1% of all tumours of the central nervous system. It originates in the tanicytes, ependymal cells present in the embryo and usually seen in adolescents and young adults. Radiologically it presents as a well delimited, heterogeneous tumour with a solid component which takes up contrast and is cystic, giving the same signal as cerebrospinal fluid (CSF). The pathological characteristics are of the formation of radial astroblastic pseudorosettes with perivascular hyalinization.

CASE REPORT

An 18 year old woman presented with a 15 month history of motor deficit of her right limbs with occasional left frontal headache and horizontal diplopia on looking towards the left. On examination there was minimal claudication of the right limbs and bilateral papilloedema. Magnetic resonance showed a very well circumscribed left prefrontal neoplasm of heterogeneous aspect, with areas of solid and cystic appearance in the different sequences. The area of cystic appearance did not show the CSF signal in all sequences of the pulse. The tumour was totally excised. On histological study there were radial astroblastic pseudorosettes with perivascular hyalinization, with two mitoses per 10 fields of great magnification and the final diagnosis was of low grade astroblastoma. The apparently cystic portion was composed of friable gelatinous tissue. Fifteen months after her operation the patient is still asymptomatic.

CONCLUSION

We report the radiological and pathological findings of a low grade astroblastoma.

[Magnetic resonance of congenital cardiopathies]

OBJECTIVE

The objective of this study was to determine the usefulness of magnetic resonance in the diagnosis and follow-up in congenital heart disease.

PATIENTS AND METHODS

Between 1992 and 1994, we have evaluated 250 patients (between 1 day-22 years of age) with congenital heart disease. We used a Philips-Gyroscan 0.5 Tesla set-up and the studies were made with ECG-gated multislice sequences with the time of repetition adapted to the cardiac frequency. The slice thicknesses were 3-10 mm and the field of view was 100-400 mm. Three axes were used: axial, oblique coronal and 30-60 degrees oblique sagittal. Three groups were made: A) Patients in whom MR imaging was the elected technique for establishment of the diagnosis; B) Patients were MR imaging was an alternative technique; and C) Patients were MR imaging was complementary to other techniques. All patients underwent a Doppler echocardiographic study or an angiocardiogram.

RESULTS

Group A) One hundred and fifty-one patients were included with the following conditions: Eighty-two with coarctation of the aorta or aortic arch interruption, 12 with vascular ring, 5 with truncus arteriosus in order to evaluate the pulmonary branches, 28 cases operated for Fallot or transposition of the great vessels for the evaluation of the pulmonary branches, 16 with single ventricle for the evaluation of the bulboventricular foramen, 5 with complex congenital heart disease and 3 with pericardial agenesia-herniation. Group B) Sixty-five patients were included in this group with the following diagnoses: Ten with aorto-pulmonary colateral arteries, 13 with anomalous pulmonary drainage of the systemic veins, 38 with tronco-conal anomalies and 4 with supravalvular aortic stenosis. Group C) Thirty-four patients with the following conditions were included in this group: Ten with common atrioventricular septal defects, 6 with tricuspid atresia, 6 with atrioventricular and ventriculoarterial discordance and 12 with other anomalies.

CONCLUSIONS

MR imaging can replace other techniques in the diagnosis and follow-up of some congenital heart diseases and in a non-invasive way.

[Evaluation of pulmonary arteries using nuclear magnetic resonance in patients with pulmonary atresia]

OBJECTIVES

Patients with pulmonary atresia and a ventricular septal defect have one outlet vessel; the aorta. The pulmonary arteries may be present or absent, and there is a collateral shunt. Magnetic resonance imaging is used to study this.

MATERIAL AND METHODS

We evaluated 10 patients with pulmonary atresia with ventricular septal defect. Five were males and the others were females, ages ranged between 1 day and 25 years, three patients were newborns. We used common planes, but mainly: axial-transverse and coronal, normal and right or left oblique projections.

RESULTS

The size of the ventricular septal defect was 1.75 +/- 0.67 cm (0.5-3.2). The pulmonary trunk was absent in 7 patients, it was atretic in 2 and it was present in one. Confluent pulmonary branches were seen in 6 patients (right 0.58 +/- 0.12, left 0.53 +/- 0.19), not confluent in 2 (with only one branch in each case) and absent in the other two. There was collateral shunt flowing from the descending aorta in 7 patients, from the ascending aorta in two and from the aortic in the final case. The ascending aorta was dilated in all cases (diameter 3.04 +/- 1.39), afterwards the relation between the ascending aorta and the descending aorta was 1.87 +/- 0.25. The aortic arch was right sided in 5 patients.

CONCLUSIONS

Magnetic resonance imaging is an alternative diagnostic method to angiocardiography. It gives complete information about the size, the position and the connection of the pulmonary arteries. It is also useful to evaluate the aortopulmonary to bronchial shunt.

[An imaging and color echo-Doppler study of interventricular defects]

OBJECTIVE

Evaluation of ventricular septal defect with two-dimensional echocardiography and color flow Doppler.

PATIENTS AND METHODS

We had studied by this method 180 patients; 97 males and 83 (mean age 1.5 +/- 1 years) diagnosed of a VSD. Cases with a complex cardiopathy were excluded from the study. The VSD was classified according to its location and relation to the tricuspid anulus and semilunar valves in perimembranous VSD, muscular VSD and subarterial double committed defect. The colour Doppler identified one or two areas of low through the ventricular septum with a zona of proximal acceleration throughout systole. Every group can be evaluated in different views but they all have a selective echocardiographic view except for muscular trabecular VSD.

RESULTS

Seventy-six patients had perimembranous VSD (30 inlet, 26 trabecular and 20 infundibular-outlet), 102 had muscular VSD (3 inlet, 97 trabecular and 2 infundibular-outlet) and 2 had a subarterial double committed defect. A ventricular septal aneurysm was associated in 20 patients with muscular or perimembranous defects. Six patients, 2 of the perimembranous trabecular VSD, 2 muscular-trabecular VSD and 2 subarterial were initially misclassified. In this last 2 cases the turbulence created in the pulmonary valve was wrongly interpreted as pulmonary valvular stenosis; subcostal view for both tracts is necessary to avoid such mistake. In conclusion, color Doppler flow mapping is very useful to differentiate the various types as VSD and aids identification of multiples ventricular septal defects.