Although intravenous (IV) contrast is not specifically needed for the diagnosis of CJD, use of IV contrast can provide important diagnostic information for identifying other known causes of RPD, most notably including autoimmune and inflammatory etiologies. HMPAO SPECT or SPECT/CT Brain Tc-99m hexamethyl-propylamine-oxime (HMPAO) single-photon emission computed tomography (SPECT)/CT of the brain may be helpful in the evaluation of a patient with suspected CJD. Tc-99m HMPAO SPECT/CT demonstrates changes in regional cerebral blood flow that can be seen even before signal changes are apparent on MRI [18,19]. Despite the increased sensitivity for early changes, the lack of specificity of the SPECT findings limits its utility as the initial imaging study. Movement Disorders and Neurodegenerative Diseases Variant 2: Chorea; suspected Huntington disease. Initial imaging. Chorea is characterized by involuntary, flowing, nonstereotyped movements that often possess a writhing quality. HD is the prototypical choreiform disorder and the most common cause of chorea in adults. However, the differential diagnosis of chorea includes a number of additional genetic and neurodegenerative disorders in addition to myriad acquired conditions, such as cerebrovascular, infectious, autoimmune, metabolic, neurodegenerative, and drug-induced syndromes. As such, the diagnostic workup, although often focused on HD, must nonetheless consider these other potential etiologies. HD is a hereditary, autosomal dominant fatal neurodegenerative disorder with complete penetrance characterized by progressive behavioral symptoms, choreoathetosis and/or rigidity, and cognitive dysfunction.
Movement Disorders and Neurodegenerative Diseases. Although intravenous (IV) contrast is not specifically needed for the diagnosis of CJD, use of IV contrast can provide important diagnostic information for identifying other known causes of RPD, most notably including autoimmune and inflammatory etiologies. HMPAO SPECT or SPECT/CT Brain Tc-99m hexamethyl-propylamine-oxime (HMPAO) single-photon emission computed tomography (SPECT)/CT of the brain may be helpful in the evaluation of a patient with suspected CJD. Tc-99m HMPAO SPECT/CT demonstrates changes in regional cerebral blood flow that can be seen even before signal changes are apparent on MRI [18,19]. Despite the increased sensitivity for early changes, the lack of specificity of the SPECT findings limits its utility as the initial imaging study. Movement Disorders and Neurodegenerative Diseases Variant 2: Chorea; suspected Huntington disease. Initial imaging. Chorea is characterized by involuntary, flowing, nonstereotyped movements that often possess a writhing quality. HD is the prototypical choreiform disorder and the most common cause of chorea in adults. However, the differential diagnosis of chorea includes a number of additional genetic and neurodegenerative disorders in addition to myriad acquired conditions, such as cerebrovascular, infectious, autoimmune, metabolic, neurodegenerative, and drug-induced syndromes. As such, the diagnostic workup, although often focused on HD, must nonetheless consider these other potential etiologies. HD is a hereditary, autosomal dominant fatal neurodegenerative disorder with complete penetrance characterized by progressive behavioral symptoms, choreoathetosis and/or rigidity, and cognitive dysfunction.