Sporadic is the most common type, comprising approximately 85% of the cases, with an annual incidence of 1 to 2 cases/million and peak age of onset from 55 to 75 years [2]. The most common clinical course of sporadic CJD is rapidly worsening dementia, which may be followed by myoclonic jerks and akinetic mutism. Sporadic CJD has a median survival of approximately 5 months [2]. The diagnosis of CJD is multifactorial and includes clinical history, physical examination, electroencephalography, diagnostic imaging, cerebrospinal fluid analysis for real-time quaking-induced conversion (CSF RT-QuIC), 14-3-3, and tau proteins, and PRNP gene sequencing [3]. FDG-PET/CT Brain PET using the tracer fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) may be helpful in the evaluation of a patient with suspected CJD. FDG-PET/CT demonstrates widespread cerebral hypometabolism, even early on in the disease process, which has been noted to correspond with histopathological astrocytosis, neuronal death, and spongiform changes [4,5]. However, the lack of specificity of the findings limit its utility as the initial imaging study. MR Spectroscopy Head Although not indicated as the initial imaging study, MR spectroscopy of the brain may be helpful in providing additional information for more atypical cases of CJD. MR spectroscopy has shown decreased absolute levels of N- acetyl aspartate and ratios of N-acetyl aspartate to other metabolites in a pattern similar to the signal abnormalities seen on T2-weighted and diffusion-weighted imaging, particularly later in the disease course [6,7]. MRI Functional (fMRI) Head There is no relevant literature for functional MRI (fMRI) of the brain in the initial imaging evaluation of a patient with RPD or suspected CJD. MRI Head In patients with RPD or suspected prion disease, MRI of the brain is the optimal imaging modality, with the most sensitive sequences being diffusion weighted and T2-fluid-attenuated inversion recovery (FLAIR) [8,9].
Movement Disorders and Neurodegenerative Diseases. Sporadic is the most common type, comprising approximately 85% of the cases, with an annual incidence of 1 to 2 cases/million and peak age of onset from 55 to 75 years [2]. The most common clinical course of sporadic CJD is rapidly worsening dementia, which may be followed by myoclonic jerks and akinetic mutism. Sporadic CJD has a median survival of approximately 5 months [2]. The diagnosis of CJD is multifactorial and includes clinical history, physical examination, electroencephalography, diagnostic imaging, cerebrospinal fluid analysis for real-time quaking-induced conversion (CSF RT-QuIC), 14-3-3, and tau proteins, and PRNP gene sequencing [3]. FDG-PET/CT Brain PET using the tracer fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) may be helpful in the evaluation of a patient with suspected CJD. FDG-PET/CT demonstrates widespread cerebral hypometabolism, even early on in the disease process, which has been noted to correspond with histopathological astrocytosis, neuronal death, and spongiform changes [4,5]. However, the lack of specificity of the findings limit its utility as the initial imaging study. MR Spectroscopy Head Although not indicated as the initial imaging study, MR spectroscopy of the brain may be helpful in providing additional information for more atypical cases of CJD. MR spectroscopy has shown decreased absolute levels of N- acetyl aspartate and ratios of N-acetyl aspartate to other metabolites in a pattern similar to the signal abnormalities seen on T2-weighted and diffusion-weighted imaging, particularly later in the disease course [6,7]. MRI Functional (fMRI) Head There is no relevant literature for functional MRI (fMRI) of the brain in the initial imaging evaluation of a patient with RPD or suspected CJD. MRI Head In patients with RPD or suspected prion disease, MRI of the brain is the optimal imaging modality, with the most sensitive sequences being diffusion weighted and T2-fluid-attenuated inversion recovery (FLAIR) [8,9].