Role of MRA in the detection of intracranial aneurysm in the acute phase of subarachnoid hemorrhage

International audienceBackground: Magnetic resonance angiography (MRA) has been evaluated for the detection of unruptured intracranial aneurysms with favorable results at 3 Tesla (3 T) and with similar diagnostic accuracy as both 3D time-of-flight (3D-TOF) and contrast-enhanced (CE-MRA) MRA. However, the diagnostic value and place of MRA in the detection of ruptured aneurysms has been little evaluated. Thus, the goal of this prospective single-center series was to assess the feasibility and diagnostic value of 3 T 3D-TOF MRA and CE-MRA for aneurysm detection in acute non-traumatic subarachnoid hemorrhage (SAH).Methods: From March 2006 to December 2007, all consecutive patients admitted to our hospital with acute non-traumatic SAH (≤ 10 days) were prospectively included in this study evaluating MRA in the diagnostic workup of SAH. Feasibility of MRA and sensitivity/specificity of 3D-TOF and CE-MRA were assessed compared with gold standard DSA.Results: In all, 84 consecutive patients (45 women, 39 men; age 23–86 years) were included. The feasibility of MRA was low (43/84, 51.2%). The reasons given for patients not undergoing magnetic resonance imaging (MRI) examination were clinical status (27 patients), potential delay in aneurysm treatment (11 patients) and contraindications to MRI (three patients). In patients explored by MRA, the sensitivity of CE-MRA (95%) was higher compared with 3D-TOF (86%) with similar specificity (80%). Also, 3D-TOF missed five aneurysms while CE-MRA missed two.Conclusion: The value of MRA in the diagnostic workup of ruptured aneurysms is limited due to its low feasibility during the acute phase of bleeding. Sensitivity for aneurysm detection was good for both MRA techniques, but tended to be better with CE-MRA

Three-dimensional dynamic time-resolved contrast-enhanced MRA using parallel imaging and a variable rate k-space sampling strategy in intracranial arteriovenous malformations

International audienceTo evaluate the effectiveness of three-dimensional (3D) dynamic time-resolved contrast-enhanced MRA (TR-CE-MRA) using a combination of a parallel imaging technique (ASSET: array spatial sensitivity encoding technique) and a time-resolved method (TRICKS: time-resolved imaging of contrast kinetics) and to compare it with 3D dynamic TR-CE-MRA using ASSET alone in the assessment of intracranial arteriovenous malformations (AVMs)

Role of MRA in the detection of intracranial aneurysm in the acute phase of subarachnoid hemorrhage

International audienceBackground: Magnetic resonance angiography (MRA) has been evaluated for the detection of unruptured intracranial aneurysms with favorable results at 3 Tesla (3 T) and with similar diagnostic accuracy as both 3D time-of-flight (3D-TOF) and contrast-enhanced (CE-MRA) MRA. However, the diagnostic value and place of MRA in the detection of ruptured aneurysms has been little evaluated. Thus, the goal of this prospective single-center series was to assess the feasibility and diagnostic value of 3 T 3D-TOF MRA and CE-MRA for aneurysm detection in acute non-traumatic subarachnoid hemorrhage (SAH).Methods: From March 2006 to December 2007, all consecutive patients admitted to our hospital with acute non-traumatic SAH (≤ 10 days) were prospectively included in this study evaluating MRA in the diagnostic workup of SAH. Feasibility of MRA and sensitivity/specificity of 3D-TOF and CE-MRA were assessed compared with gold standard DSA.Results: In all, 84 consecutive patients (45 women, 39 men; age 23–86 years) were included. The feasibility of MRA was low (43/84, 51.2%). The reasons given for patients not undergoing magnetic resonance imaging (MRI) examination were clinical status (27 patients), potential delay in aneurysm treatment (11 patients) and contraindications to MRI (three patients). In patients explored by MRA, the sensitivity of CE-MRA (95%) was higher compared with 3D-TOF (86%) with similar specificity (80%). Also, 3D-TOF missed five aneurysms while CE-MRA missed two.Conclusion: The value of MRA in the diagnostic workup of ruptured aneurysms is limited due to its low feasibility during the acute phase of bleeding. Sensitivity for aneurysm detection was good for both MRA techniques, but tended to be better with CE-MRA

Anatomical and functional MR imaging to define tumoral boundaries and characterize lesions in neuro-oncology

International audienceNeuroimaging and especially MRI has emerged as a necessary imaging modality to detect, measure, characterize and monitor brain tumors. Advanced MRI sequences such as perfusion MRI, diffusion MRI and spectroscopy as well as new post-processing techniques such as automatic segmentation of tumors and radiomics play a crucial role in characterization and follow up of brain tumors. The purpose of this review is to provide an overview on anatomical and functional MR imaging use for brain tumors boundaries determination and tumor characterization in the specific context of radiotherapy. The usefulness of anatomical and functional MR imaging on particular challenges posed by radiotherapy such as pseudoprogression and pseudoresponse and new treatment strategies such as dose painting is also described.Les avancées en neuro-imagerie, principalement liées au développement de l’IRM, ont rendu cette modalité centrale dans la prise en charge des patients porteurs de tumeur cérébrale. L’IRM, par son approche anatomique, permet de détecter, localiser et caractériser les lésions. L’application de séquences avancées d’IRM de type imagerie de perfusion, de spectroscopie ou de diffusion, ainsi que les nouveaux post-traitements permettant une segmentation ou une caractérisation automatique des lésions, apportent de nouvelles possibilités pour affiner la caractérisation des tumeurs tant au moment du diagnostic initial que lors du traitement par radiothérapie et du suivi. Le but de cette revue de littérature est de donner un aperçu de l’utilisation des imageries IRM anatomique et fonctionnelle utilisées pour la détermination des contours des différentes tumeurs cérébrales dans le contexte particulier de la radiothérapie. L'utilité de l'IRM anatomique et fonctionnelle est également examinée, en portant une attention particulière aux défis posés par la radiothérapie, tels que la pseudoprogression et la pseudoréponse, ainsi que par de nouvelles stratégies de traitement personnalisées, comme la dose painting

The Power Button Sign: A Newly Described Central Sulcal Pattern on Surface Rendering MR Images of Type 2 Focal Cortical Dysplasia

International audiencePURPOSE:To compare the occurrence of several central sulcus variants and to assess the reproducibility of a sulcal pattern named the power button sign (PBS) in patients with type 2 focal cortical dysplasia (FCD2) and healthy control subjects.MATERIALS AND METHODS:The local institutional review board approved the study, and written informed consent was waived for patients and was obtained from control subjects. Four readers reviewed three-dimensional (3D) T1-weighted magnetic resonance (MR) images in 37 patients (13 with negative MR imaging findings) with histologically proven FCD2 of the central region and 44 control subjects on the basis of a visual analysis of a 3D reconstruction of cortical folds. They searched for central sulcus variations (interruptions, side branches, and connections) and for a particular sulcal pattern, namely, the interposition of a precentral sulcal segment between the central sulcus and one of its hook-shaped anterior ascending branches (ie, PBS). Inter- and intraobserver reliability, specificity, and sensitivity were calculated.RESULTS:The central sulcus showed a greater number of side branches (P < .001) and was more frequently connected to the precentral sulcus (P < .001) in patients with FCD2 than in control subjects. The PBS was found in 23 (62%) of 37 total patients with FCD2, in six (46%) of 13 with negative MR imaging findings, and in only one control subject. Inter- and intraobserver rates were excellent (0.88 and 0.93, respectively) for the detection of PBS. FCD2 was located either in the depth of the ascending branch of the central sulcus (14 of 23, 61%) or in its immediate vicinity (nine of 23).CONCLUSION:Given its excellent reproducibility and specificity, the PBS, when present, could become a useful qualitative diagnostic MR criterion of FCD2 in the central region

High-resolution MR imaging of the cervical arterial wall:what the radiologist needs to know.

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Brain networks of spatial awareness: evidence from diffusion tensor imaging tractography.

International audienceLeft unilateral neglect, a dramatic condition which impairs awareness of left-sided events, has been classically reported after right hemisphere cortical lesions involving the inferior parietal region. More recently, the involvement of long range white matter tracts has been highlighted, consistent with the idea that awareness of events occurring in space depends on the coordinated activity of anatomically distributed brain regions. Damage to the superior longitudinal fasciculus (SLF), linking parietal to frontal cortical regions, or to the inferior longitudinal fasciculus (ILF), connecting occipital and temporal lobes, has been described in neglect patients. In this study, four right-handed patients with right hemisphere strokes underwent a high definition anatomical MRI with diffusion tensor imaging (DTI) sequences and a pencil and paper neglect battery of tests. We used DTI tractography to visualise the SLF, ILF and the inferior fronto-occipital fasciculus (IFOF), a pathway running the depth of the temporal lobe, not hitherto associated with neglect. Two patients with cortical involvement of the inferior parietal and superior temporal regions, but intact and symmetrical fasciculi, showed no signs of neglect. The other two patients with signs of left neglect had superficial damage to the inferior parietal cortex and white matter damage involving the IFOF. These findings suggest that superficial damage to the inferior parietal cortex per se may not be sufficient to produce visual neglect. In some cases, a lesion to the direct connections between ventral occipital and frontal regions (ie, IFOF) may contribute to the manifestation of neglect by impairing the top down modulation of visual areas from the frontal cortex