The abovementioned findings are optimally visualized on noncontrast MRI; IV contrast is not needed. US Duplex Doppler Carotid Artery Atherosclerotic burden, as defined by carotid ultrasound (US), is associated with worse cognitive performance and subsequent cognitive decline [67]. However, US duplex Doppler is not needed to diagnose VaD. Variant 5: Suspected idiopathic normal-pressure hydrocephalus. Initial imaging. Normal-pressure hydrocephalus (NPH) is characterized by the clinical triad of dementia, gait disturbance, and urinary incontinence. Other diagnostic features include normal CSF pressure at lumbar puncture, communicating hydrocephalus documented on MRI or CT, and ventricular influx but no passage of isotope over the convexities on radionuclide DTPA cisternography. The Guideline Development, Dissemination, and Implementation Subcommittee of the AAN has concluded that shunting is possibly effective in idiopathic NPH (INPH) [68]. Several clinical, laboratory, and imaging signs can improve distinction between responders and nonresponders to shunting. However, there is no test or combination of clinical findings and tests that accurately predicts response to shunting. Clinical features that favor shunt responsiveness include predominance of gait disturbance, mild to moderate degree of dementia, and rapid clinical progression of urinary incontinence. Imaging features of responders versus nonresponders are discussed below. CT Head CT head without IV contrast is an appropriate first-line imaging test to evaluate for ventriculomegaly out of proportion to sulci and to exclude other pathologies. It can also show transependymal CSF flow. CT head with IV contrast is not indicated for initial evaluation of NPH. MR Spectroscopy Head MR spectroscopy is not useful in differentiating INPH from other types of dementia nor does it help in patient selection for ventriculoperitoneal shunting [69].
Dementia. The abovementioned findings are optimally visualized on noncontrast MRI; IV contrast is not needed. US Duplex Doppler Carotid Artery Atherosclerotic burden, as defined by carotid ultrasound (US), is associated with worse cognitive performance and subsequent cognitive decline [67]. However, US duplex Doppler is not needed to diagnose VaD. Variant 5: Suspected idiopathic normal-pressure hydrocephalus. Initial imaging. Normal-pressure hydrocephalus (NPH) is characterized by the clinical triad of dementia, gait disturbance, and urinary incontinence. Other diagnostic features include normal CSF pressure at lumbar puncture, communicating hydrocephalus documented on MRI or CT, and ventricular influx but no passage of isotope over the convexities on radionuclide DTPA cisternography. The Guideline Development, Dissemination, and Implementation Subcommittee of the AAN has concluded that shunting is possibly effective in idiopathic NPH (INPH) [68]. Several clinical, laboratory, and imaging signs can improve distinction between responders and nonresponders to shunting. However, there is no test or combination of clinical findings and tests that accurately predicts response to shunting. Clinical features that favor shunt responsiveness include predominance of gait disturbance, mild to moderate degree of dementia, and rapid clinical progression of urinary incontinence. Imaging features of responders versus nonresponders are discussed below. CT Head CT head without IV contrast is an appropriate first-line imaging test to evaluate for ventriculomegaly out of proportion to sulci and to exclude other pathologies. It can also show transependymal CSF flow. CT head with IV contrast is not indicated for initial evaluation of NPH. MR Spectroscopy Head MR spectroscopy is not useful in differentiating INPH from other types of dementia nor does it help in patient selection for ventriculoperitoneal shunting [69].