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.

An In Vivo Assessment of Regional Brain Temperature during Whole-Body Cooling for Neonatal Encephalopathy.

OBJECTIVE: To assess differences in regional brain temperatures during whole-body hypothermia and test the hypothesis that brain temperature profile is nonhomogenous in infants with hypoxic-ischemic encephalopathy. STUDY DESIGN: Infants with hypoxic-ischemic encephalopathy were enrolled prospectively in this observational study. Magnetic resonance (MR) spectra of basal ganglia, thalamus, cortical gray matter, and white matter (WM) were acquired during therapeutic hypothermia. Regional brain tissue temperatures were calculated from the chemical shift difference between water signal and metabolites in the MR spectra after performing calibration measurements. Overall difference in regional temperature was analyzed by mixed-effects model; temperature among different patterns and severity of injury on MR imaging also was analyzed. Correlation between temperature and depth of brain structure was analyzed using repeated-measures correlation. RESULTS: In total, 53 infants were enrolled (31 girls, mean gestational age: 38.6 ± 2 weeks; mean birth weight: 3243 ± 613 g). MR spectroscopy was acquired at mean age of 2.2 ± 0.6 days. A total of 201 MR spectra were included in the analysis. The thalamus, the deepest structure (36.4 ± 2.3 mm from skull surface), was lowest in temperature (33.2 ± 0.8°C, compared with basal ganglia: 33.5 ± 0.9°C; gray matter: 33.6 ± 0.7°C; WM: 33.8 ± 0.9°C, all P < .001). Temperatures in more superficial gray matter and WM regions (depth: 21.9 ± 2.4 and 21.5 ± 2.2 mm) were greater than the rectal temperatures (33.4 ± 0.4°C, P < .03). There was a negative correlation between temperature and depth of brain structure (rrm = -0.36, P < .001). CONCLUSIONS: Whole-body hypothermia was effective in cooling deep brain structures, whereas superficial structures were warmer, with temperatures significantly greater than rectal temperatures.

Multimodality Imaging Approaches in Alzheimer's disease. Part II: 1H MR spectroscopy, FDG PET and Amyloid PET / Abordagem e multimodalidade de imagem em doença de Alzheimer. Parte II: espectroscopia, FDG-PET, e imagem Amilóide

ABSTRACT. In this Part II review, as a complement to the Part I published in this supplement, the authors cover the imaging techniques that evaluates the Alzheimer's disease according to the different metabolic and molecular profiles. In this section MR spectroscopy, FDG-PET and amyloid PET are deeply discussed.

RESUMO Nesta revisão Parte II, como complemento da revisão Parte I publicada nesta edição, os autores descrevem as técnicas de imagem que avaliam a doença de Alzheimer de acordo com os diferentes perfis metabólicos e moleculares que caracterizam esta doença. Nesta seção são discutidos em profundidade a espectroscopia por ressonância magnética, FDG-PET and imagem com marcadores de peptide beta amilóide.

MRI evaluation and safety in the developing brain.

Magnetic resonance imaging (MRI) evaluation of the developing brain has dramatically increased over the last decade. Faster acquisitions and the development of advanced MRI sequences, such as magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI), perfusion imaging, functional MR imaging (fMRI), and susceptibility-weighted imaging (SWI), as well as the use of higher magnetic field strengths has made MRI an invaluable tool for detailed evaluation of the developing brain. This article will provide an overview of the use and challenges associated with 1.5-T and 3-T static magnetic fields for evaluation of the developing brain. This review will also summarize the advantages, clinical challenges, and safety concerns specifically related to MRI in the fetus and newborn, including the implications of increased magnetic field strength, logistics related to transporting and monitoring of neonates during scanning, and sedation considerations, and a discussion of current technologies such as MRI conditional neonatal incubators and dedicated small-foot print neonatal intensive care unit (NICU) scanners.

Multimodality Imaging Approaches in Alzheimer's disease. Part II: 1H MR spectroscopy, FDG PET and Amyloid PET.

In this Part II review, as a complement to the Part I published in this supplement, the authors cover the imaging techniques that evaluates the Alzheimer's disease according to the different metabolic and molecular profiles. In this section MR spectroscopy, FDG-PET and amyloid PET are deeply discussed.

Nesta revisão Parte II, como complemento da revisão Parte I publicada nesta edição, os autores descrevem as técnicas de imagem que avaliam a doença de Alzheimer de acordo com os diferentes perfis metabólicos e moleculares que caracterizam esta doença. Nesta seção são discutidos em profundidade a espectroscopia por ressonância magnética, FDG-PET and imagem com marcadores de peptide beta amilóide.

Hypoxic-ischemic injuries: the role of magnetic resonance spectroscopy.

Hypoxic ischemic injuries are a very common clinical situation in the pediatric population. This article focuses on the metabolic signature of hypoxic ischemic injuries and metabolic indicators of prognosis.

Pediatric brain tumors.

Pediatric brain tumors are the most common solid tumor of childhood. This article focuses on the metabolic signature of common pediatric brain tumors using MR spectroscopic analyses.

Evaluación preoperatoria de los tumores cerebrales malignos mediante resonancia magnética con espectroscopia y difusión ponderada / Preoperative evaluation of solitary malignant brain tumors with MR spectroscopy and diffusion weighted imaging

One hundred eleven patients with solitary malignant brain tumors (55 low-, 31 high-grade gliomas, and 25 metastases) were prospectively evaluated. Gliomas classified as low- and highgrade by NAA/Cho, Cho/Cr, Lac/Cr and NADCT (p < 0.001). Higher degree of malignancy was associated with Cho/Cr (r = 0.648, p < 0.001), Lac/Cr (r = 0.583, p < 0.001), NAA/Cho (r = -0.657, p < 0.001) and NADCT (r = -0.473, p < 0.001). While NADCT , Lip/Cr (p < 0.001), NAA/Cho, Lac/Cr, NADCP and Cho/Cr (p < 0.05) could differentiate metastases from low-grade gliomas; NAA/Cho, Cho/Cr, Lip/Cr (p < 0.001), NAA/Cr, Lac/Cr and NADCP (p < 0.05) could differentiate them from high-grade gliomas. Except Lip/Cr ratio (p < 0.05), no parameter was useful to differentiate high grade gliomas from each other. Low-grade non-astrocytic gliomas had significantly higher Cho/Cr ratios than low-grade astrocytomas (p < 0.05). Furthermore pilocytic astrocytomas had significantly higher NAA/Cho and lesser NADCP than diffuse astrocytomas and low-grade non-astrocytic gliomas. Diffuse astrocytomas had also higher Lip/Cr than pilocytic astrocytomas, low-grade non-astrocytic gliomas and anaplastic astrocytomas. In the differentiation of tumor subgroups, highest Pearson correlation was found in Lip/Cr (r = 0.685, p < 0.001), NAA/Cho (r = -0.567, p < 0.001), NADCP (r = 0.522, p < 0.001), Lac/Cr (r = 0.437, p < 0.001) and Cho/Cr (r = 0.395, p < 0.001). MR spectroscopy and diffusion weighted images can support additional information to MR imaging in the differentiation and grading of malignant brain tumors

Se evaluaron en forma prospectiva 111 pacientes con tumores cerebrales malignos y solitarios (55 gliomas de bajo grado, 31 de alto grado, y 25 metástasis). Los gliomas fueron clasificados como de bajo y alto grado según NAA/Cho, Cho/Cr, Lac/Cr y CDANT (p < 0.001). Un grado mayor de malignidad se asoció con Cho/Cr (r = 0.648; p < 0.001); Lac/Cr (r = 0.583; p < 0.001); NAA/Cho (r = -0.657; p < 0.001); y CDANT (r = -0.473; p < 0.001). Mientras que CDANT , Lip/Cr (p < 0.001), NAA/Cho, Lac/Cr, CDANP y Cho/Cr (p < 0.05) pudieron diferenciar las metástasis de los gliomas de bajo grado; NAA/Cho, Cho/Cr, Lip/Cr (p < 0.001), NAA/Cr, Lac/Cr y CDANP (p < 0.05) pudieron diferenciarlas de los gliomas de alto grado. Excepto por la relación Lip/Cr (p < 0.05), ningún parámetro resultó de utilidad para diferenciar los gliomas de alto grado entre sí. Los gliomas no astrocíticos de bajo grado tuvieron relaciones Cho/Cr significativamente más elevadas que los astrocitomas de bajo grado (p < 0.05). Además, los astrocitomas pilocíticos tuvieron relaciones NAA/Cho significativamente más elevadas pero menores CDANP que los astrocitomas difusos y los gliomas no astrocíticos de bajo grado. Los astrocitomas difusos también presentaron relaciones Lip/Cr más elevadas que los de tipo pilocítico, los gliomas no astrocíticos de bajo grado y los anaplásicos. En la diferenciación de los subgrupos tumorales, la correlación de Pearson más elevada se halló en la relación Lip/Cr (r = 0.685; p < 0.001), NAA/Cho (r = -0.567; p < 0.001), CDANP (r = 0.522; p < 0.001), Lac/Cr (r = 0.437; p < 0.001) y Cho/Cr (r = 0.395; p < 0.001). La espectroscopia por resonancia magnética y las imágenes de difusión ponderada pueden aportar información adicional a las imágenes obtenidas mediante resonancia magnética para la diferenciación y estadificación de los tumores cerebrales malignos