ABSTRACT
Dynamic susceptibility contrast (DSC) perfusion imaging has been in clinical use for various indications, including characterization and grading of intracranial neoplasms. However, several technical factors can lead to pitfalls in image interpretation. This review discusses the extraction of T1 and T2* information from mean curve analysis of DSC perfusion imaging of various brain tumors, which provides further insights into tumor biology and, thus, may be useful in the differential diagnosis of such tumors. Indeed, by looking at the mean time-signal intensity curve from the tumor bed in addition to the rCBV maps, it is possible to obtain further inferences of capillary density and lesion leakiness. When dynamic contrast enhanced (DCE) T1 perfusion is not available, DSC perfusion with mean curve analysis appears to be a valid alternative for characterizing various brain neoplasms in a routine clinical setting.
Subject(s)
Brain Neoplasms/diagnosis , Magnetic Resonance Imaging/methods , Neuroimaging/methods , Brain Neoplasms/pathology , Diagnosis, Differential , HumansABSTRACT
BACKGROUND AND PURPOSE: As both tuberculoma and metastasis can manifest as solitary or multiple ring-enhancing intra-axial lesions that are difficult to differentiate by conventional magnetic resonance imaging (MRI), we hypothesized that the use of diffusion and perfusion MRI would make differentiation of these pathologies possible. MATERIALS AND METHODS: Diffusion and T2*-weighted dynamic contrast-enhanced perfusion MRI scans from 11 patients with histologically proven tuberculoma or metastasis were retrospectively reviewed by two radiologists who were blinded to the pathology. All patients had a ring-enhancing lesion on conventional MRI. Apparent diffusion coefficient (ADC) values and regional cerebral blood volume (rCBV) were calculated from the walls of the lesions. RESULTS: Lesions showed different perfusion characteristics depending on whether they were due to tuberculosis or metastasis. The mean rCBV ratio between the lesion periphery and normal white matter was inferior to one for tubercular lesions and greater than five for metastases. However, ADC values were similar. CONCLUSION: Measuring rCBV obtained by T2*-weighted dynamic contrast-enhanced perfusion MRI can help in differentiating intracranial tubercular mass lesions and metastases.
Subject(s)
Brain Neoplasms/secondary , Diffusion Magnetic Resonance Imaging , Image Enhancement , Image Processing, Computer-Assisted , Magnetic Resonance Angiography , Tuberculosis, Meningeal/diagnosis , Adolescent , Adult , Blood Volume/physiology , Brain/pathology , Brain Neoplasms/diagnosis , Brain Neoplasms/pathology , Child , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Regional Blood Flow/physiology , Retrospective Studies , Sensitivity and Specificity , Tuberculosis, Meningeal/pathology , Young AdultABSTRACT
A 29-year-old immunocompetent patient presented with a 3-month history of headache and vomiting. Computed tomography (CT) and conventional magnetic resonance imaging (MRI) revealed a mass lesion in the right sphenoid wing. The conventional imaging findings were typical of meningioma. However, diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI) and perfusion-weighted imaging (PWI) all revealed details that were unusual for a meningioma. DWI showed diffusion blackout, perfusion was not raised in PWI, and susceptibility effects were noted in SWI. Based on these findings, the possibility of granuloma was kept as the differential diagnosis. Histopathological examination of the lesion was suggestive of fungal granuloma. This case report highlights the importance of advanced neuroimaging techniques in differentiating meningioma and granuloma.
