Signal Source in Heavily Diffusion-Weighted functional MRI
نویسندگان
چکیده
Introduction: It has been suggested that heavily diffusion-weighted (DW) functional MRI (fMRI) signal changes originate from water in a slow diffusion phase and reflect neuronal activity via cell-swelling [1]. However, several investigations comparing signal changes during visual stimulation and hypercapnia have not arrived at any conclusive agreement on the signal source [2-4]. The role of the BOLD effect in heavily DW fMRI is also still unclear. In this study, we measured the transverse relaxation rate at different b-values and estimated the contribution of BOLD to DW fMRI.
منابع مشابه
Dynamic Contrast Magnetic Resonance Imaging (DCE-MRI) and Diffusion Weighted MR Imaging (DWI) for Differentiation between Benign and Malignant Salivary Gland Tumors
Background: Salivary gland tumors form nearly 3% of head and neck tumors. Due to their large histological variety and vicinity to facial nerves, pre-operative diagnosis and differentiation of benign and malignant parotid tumors are a major challenge for radiologists. Objective: The majority of these tumors are benign; however, sometimes they tend to transform into a malignant form. Functional M...
متن کاملSignal Intensity of High B-value Diffusion-weighted Imaging for the Detection of Prostate Cancer
Background: Diffusion-weighted imaging (DWI) is a main component of multiparametric MRI for prostate cancer detection. Recently, high b value DWI has gained more attention because of its capability for tumor characterization. Objective: To assess based on histopathological findings of transrectal ultrasound (TRUS)-guided prostate biopsy as a reference, an...
متن کاملStructural Findings in the Brain MRI of Patients with Acute Carbon Monoxide Poisoning
Background: Carbon monoxide (CO) poisoning may lead to hypoxic/anoxic injury and eventually ischemic encephalopathy. Magnetic resonance imaging (MRI) has a well-recognized role in assessment of the severity of brain damage caused by CO poisoning. In this study, we aimed to present and analyze the structural abnormalities in the brain MRI and especially in diffusion weighted MRI (DWI) images in ...
متن کاملبررسی ارزش Diffusion Weighted Imaging در تصاویر MRI برای تشخیص سرطان پروستات
Background: Prostate cancer is the third leading cause of death and is the most common cause of cancer in elderly men. Regarding to the low accuracy of screening methods such as prostate-specific antigen (PSA), Digital Rectal Examination (DRE) and trans rectal ultrasound (TRUS) in detection and localization of tumor, Magnetic Resonance Imaging (MRI) and Diffusion Weighted Imaging (DWI) attracte...
متن کاملI-45: Advance MRI Sequences in Pelvic Endometriosis
Background: To assess MRI in diagnosing endometriotic lesions, emphasizing T2*weighted imaging efficacy. Materials and Methods: This prospective study of 48 females (22-38 years, average 29.6) clinically suspected of endometriosis from September 2009 to April 2012. MRI was performed with a 1.5 T imager (Siemens) with a body array coil. T1, T2 and T2* weighted (2D-FLASH) sequences were obtained ...
متن کامل