Apport de l’IRM de perfusion et de la spectroscopie dans le diagnostic de toxoplasmose cérébrale atypique

Approach to an Intracranial Mass in Patients With HIV

PURPOSE OF REVIEW

Space-occupying lesions represent a diagnostic challenge among people with the human immunodeficiency virus, acquired immunodeficiency syndrome (HIV/AIDS). To determine the best diagnostic approach to the wide array of possible etiologies and provide a thorough interpretation of neuroimaging in order to narrow a hierarchical differential diagnosis among these patients. Given that there is no pathognomonic neuroimaging pattern in this clinical setting, we searched results from brain biopsies to best determine the etiology of commonly found lesions.

RECENT FINDINGS

Multimodal brain MRI and MRI spectroscopy (MRS) often provide the most valuable information in the study of focal masses among people with HIV/AIDS. Brain biopsy appears safe and provides high diagnostic yields in these patients. Among patients with HIV/AIDS who present with space-occupying intracranial lesions, brain MRI and MRS are useful tests. However, in cases of diagnostic uncertainty, brain biopsy is a safe procedure and should be performed. The role of metabolic studies like ²⁰¹Th-SPECT or PET is useful in the detection of primary central nervous system lymphoma.

Assessment of Primary Brain Lymphoma Using Multimodal Magnetic Resonance Imaging and Proton Magnetic Resonance Spectroscopy

Objectives:

The primary lymphoma of the central nervous system is a cancer rare. The diagnosis of this tumoral entity must be considered as an emergency considering the therapeutical involved. Therefore, we report this entity while reporting diagnostic challenges.

Patients and Methods:

Unfortunately, the conventional clinical and imaging signs can be confusing and might contribute to delay the diagnosis process of potentially curable pathological entity. The diagnosis confirmation in immunocompetent patients is based on a stereotaxic biopsy.

Results and Conclusion:

In this paper, we report a case illustrating the contribution of multimodal imaging including diffusion-weighted magnetic resonance imaging (MRI), diffusion tensor MRI, perfusion MRI, and proton MR spectroscopy to the diagnostic approach of the atypical primary lymphoma of the central nervous system.

Parasitic diseases of the central nervous system: lessons for clinicians and policy makers

Parasitic diseases of the central nervous system are associated with high mortality and morbidity, especially in resource-limited settings. The burden of these diseases is amplified as survivors are often left with neurologic sequelae affecting mobility, sensory organs, and cognitive functions, as well as seizures/epilepsy. These diseases inflict suffering by causing lifelong disabilities, reducing economic productivity, and causing social stigma. The complexity of parasitic life cycles and geographic specificities, as well as overlapping clinical manifestations in the host reflecting the diverse pathogenesis of parasites, can present diagnostic challenges. We herein provide an overview of these parasitic diseases and summarize clinical aspects, diagnosis, therapeutic strategies and recent milestones, and aspects related to prevention and control.

Magnetic resonance features of pyogenic brain abscesses and differential diagnosis using morphological and functional imaging studies: a pictorial essay

The aim of this paper is to illustrate the potential of magnetic resonance imaging (MRI) in diagnosis, differential diagnosis, treatment planning and evaluation of therapy effectiveness of pyogenic brain abscesses, through the use of morphological (or conventional) and functional (or advanced) sequences. Conventional MRI study is useful for the identification of lesions, to determine the location and morphology and allows a correct hypothesis of nature in the most typical cases. However, the differential diagnosis from other brain lesions, such as non-pyogenic abscesses or necrotic tumors (high-grade gliomas and metastases) is often only possible through the use of functional sequences, as the measurement of diffusion with apparent diffusion coefficient (DWI-ADC), proton magnetic resonance spectroscopy ((1)H-MRS) and perfusion weighted imaging (PWI), which complement the morphological sequences and provide essential information on structural, metabolic and hemodynamic characteristics allowing greater neuroradiological confidence. Modern diagnostic MRI of pyogenic brain abscesses cannot be separated from knowledge, integration and proper use of the morphological and functional sequences.

Perfusion imaging in brain disease

Perfusion CT or MRI have been extensively developed over the last years and are accessible on most imaging machines. Perfusion CT has taken a major place in the assessment of a stroke. Its role has to be specified for the diagnosis and treatment of the vasospasm, complicating a subarachnoid hemorrhage. Perfusion MRI should be included in the assessment of any brain tumor, both at the time of the diagnosis as well as in the post-treatment monitoring. It is included in the multimodal approach required for the optimum treatment of this disease. The applications in epilepsy and the neurodegenerative diseases are in the evaluation process.

Brain infections

Brain infections are relatively rare, but they are potentially serious and have a poor prognosis. The cornerstone of the diagnosis is cerebrospinal fluid (CSF) analysis. Imaging is not systematic, but the indications of imaging are broad, particularly when faced with suspected focal damage, depending on the characteristics of the patient (child, immunosuppressed patient, geographic origin, etc.). It is based on MRI, which allows for aetiological diagnosis and an extension evaluation. In addition, in a certain number of cases, the type of infection is not known and it is up to the MRI via use of an exhaustive technique to diagnose an infectious origin when faced with a mass syndrome. This technical mastery, associated with knowledge of major brain infections, their method of contamination and their particular appearance on the MRI, should make it possible for the radiologist to fulfill his or her diagnostic role.