The role of dynamic susceptibility contrast-enhanced perfusion MR imaging in differentiating between infectious and neoplastic focal brain lesions: results from a cohort of 100 consecutive patients.

BACKGROUND AND PURPOSE: Differentiating between infectious and neoplastic focal brain lesions that are detected by conventional structural magnetic resonance imaging (MRI) may be a challenge in routine practice. Brain perfusion-weighted MRI (PWI) may be employed as a complementary non-invasive tool, providing relevant data on hemodynamic parameters, such as the degree of angiogenesis of lesions. We aimed to employ dynamic susceptibility contrast-enhanced perfusion MR imaging (DSC-MRI) to differentiate between infectious and neoplastic brain lesions by investigating brain microcirculation changes. MATERIALS AND METHODS: DSC-MRI perfusion studies of one hundred consecutive patients with non-cortical neoplastic (n = 54) and infectious (n = 46) lesions were retrospectively assessed. MRI examinations were performed using a 1.5-T scanner. A preload of paramagnetic contrast agent (gadolinium) was administered 30 seconds before acquisition of dynamic images, followed by a standard dose 10 seconds after starting imaging acquisitions. The relative cerebral blood volume (rCBV) values were determined by calculating the regional cerebral blood volume in the solid areas of lesions, normalized to that of the contralateral normal-appearing white matter. Discriminant analyses were performed to determine the cutoff point of rCBV values that would allow the differentiation of neoplastic from infectious lesions and to assess the corresponding diagnostic performance of rCBV when using this cutoff value. RESULTS: Neoplastic lesions had higher rCBV values (4.28±2.11) than infectious lesions (0.63±0.49) (p<0.001). When using an rCBV value <1.3 as the parameter to define infectious lesions, the sensitivity of the method was 97.8% and the specificity was 92.6%, with a positive predictive value of 91.8%, a negative predictive value of 98.0%, and an accuracy of 95.0%. CONCLUSION: PWI is a useful complementary tool in distinguishing between infectious and neoplastic brain lesions; an elevated discriminatory value for diagnosis of infectious brain lesions was observed in this sample of patients when the rCBV cutoff value was set to 1.3.

Perfusion-weighted magnetic resonance imaging in the evaluation of focal neoplastic and infectious brain lesions / Perfusão por ressonância magnética na avaliação das lesões focais neoplásicas e infecciosas do encéfalo

Magnetic resonance imaging (MRI) is the gold standard method for brain assessment however the conventional MRI techniques may present limitations by only providing qualitative or anatomic parameters. Over recent decades, new complementary MRI techniques have been developed that supply quantitative parameters providing functional or metabolic-biochemical data. Perfusion-weighted imaging, one of these techniques, has become a powerful tool in neuroradiology. The goal of this article is to present a review about the role of perfusion-weighted MRI in the evaluation of solitary or multiple, neoplastic and infectious, focal brain lesions. Brain perfusion studies can be achieved as a complementary method to conventional MRI techniques to provide hemodynamic parameters using a non-invasive technique. This method demonstrates the degree of angiogenesis of lesions and is thus useful in the differentiation between neoplastic and infectious lesions, primary tumors and solitary metastases and in the post-treatment follow up to differentiate between tumoral recurrence and radionecrosis by identifying the presence or absence of hyperperfusion.

A ressonância magnética (RM) é o método de diagnóstico por imagem de escolha na avaliação encefálica, entretanto as técnicas convencionais de RM podem apresentar limitações por fornecerem somente parâmetros qualitativos ou anatômicos. Nas últimas décadas, têm surgido novas técnicas complementares de RM que fornecem parâmetros quantitativos proporcionando informações funcionais ou metabólico-bioquímicas. A perfusão é atualmente uma destas técnicas que vem se apresentando como uma importante ferramenta na neurorradiologia. O objetivo deste artigo é apresentar uma revisão sobre o papel da seqüência de perfusão por RM na avaliação das lesões focais neoplásicas e infecciosas, únicas ou múltiplas, do encéfalo. O estudo da perfusão encefálica pode ser realizado como método complementar às técnicas convencionais de RM,permitindo o acesso aos parâmetros hemodinâmicos de uma maneira não invasiva e demonstrando o grau de angiogênese das lesões sendo, portanto, útil na diferenciação entre lesões neoplásicas e infecciosas, tumor primário e metástase única e no seguimento pós-tratamento para a diferenciação entre recidiva tumoral e radionecrose, através da demonstração da presença ou ausência de hiperperfusão.

Achados clínicos e radiológicos do rabdomiossarcoma embrionário de orelha média e osso temporal em crianças / Clinical and radiological findings of the middle ear' embryonal rhabdomyosarcoma and temporal bone in the children

Introdução: O rabdomiossarcoma é o sarcoma de partes moles mais comum em crianças. É considerado uma neoplasia maligna derivada do músculo esquelético estriado e que se origina em qualquer parte do corpo. A cabeça, pescoço, órbita, base do crânio, cavidade nasal e nasofaringe são os sítios de origem mais comuns. Relato do Caso: Descrevemos uma apresentação incomum do rabdomiossarcoma embrionário em uma criança de 4 anos, com lesões sincrônicas na base do crânio, orelha média e osso frontal, enfatizando os achados clínicos e radiológicos.

Introduction: The rhabdomyosarcoma is a sarcoma of soft parts more common in the children. It is considered a malignant neoplasm derivative of the striated skeletal muscle and, which is originated in any part of the body. The head, neck, orbit, cranial base, nasal cavity and nasopharynx are the local of origin most common. Case Report: We describe a uncommon presentation of the embryonal rhabdomyosarcoma in a four-year-old child, with synchronous lesions in the cranial base, middle ear and, frontal bone emphasizing the clinical and radiological findings.