The Additional Value of PET in the Assessment of Cerebral Small Vessel Disease

Abstract

The diagnosis of cerebral small vessel disease (SVD) is difficult because there is no consensus on clinical criteria, and therefore imaging is important for diagnosis. Most patients undergo brain imaging by CT, which is able to detect ischemic strokes, hemorrhages, and brain atrophy and may also indicate white matter changes. MRI remains the key neuroimaging modality and is preferred to CT in vascular cognitive impairment (VCI) because it has higher sensitivity and specificity for detecting pathologic changes. These modalities for imaging morphology permit detection of vascular lesions traditionally attributed to VCI in subcortical areas of the brain, single infarction or lacunes in strategic areas (thalamus or angular gyrus), or large cortical-subcortical lesions reaching a critical threshold of tissue loss. In SVD, multiple punctuate or confluent lesions can be seen in the white matter by MRI and were called leukoaraiosis. Another major neuroimaging finding of SVD in VCI are microhemorrhages. However, whereas CT and MRI are able to detect morphologic lesions, these modalities cannot determine functional consequences of the underlying pathologic changes. PET can support the clinical diagnosis by visualizing cerebral functions in typically affected brain regions. In SVD, F-FDG PET can clearly differentiate scattered areas of focal cortical and subcortical hypometabolism that differ from the typical metabolic pattern seen in Alzheimer dementia (AD) with marked hypometabolism affecting the association areas. Additional PET tracers can further support the diagnosis of a type of dementia and also yield information on the underlying pathophysiology.

EEG measures for clinical research in major vascular cognitive impairment: recommendations by an expert panel

“…Although the above neuroimaging techniques can adequately reveal morphologic brain vascular lesions, they cannot stand for pathologic sequelae at the neural metabolic level to probe neurodegeneration of synaptic contacts and neural loss. To this purpose, F-18 Fluorodeoxyglucose positron emission tomography (FDG-PET) in the resting state condition can complement MRI markers, detecting hypometabolism of cortical gray matter regions as a reflection of that neurodegeneration ( Heiss, 2018 ;Heiss and Zimmermann-Meinzingen, 2012 ).…”

Neuromelanin‐sensitive MRI in the differential diagnosis of elderly white matter lesion from Parkinson’s disease

“…Therefore, we could not directly compare the utility of neuromelanin MRI among other imaging modalities. However, previous reports show that, in order to differentiate WML from PD/DLB, not only conventional MRI but also tractography using diffusion weighted images (DWI) of MRI can detect disrupted white matter integrity . Cerebral blood flow or glucose metabolism images show frontal dominant decrease in perfusion/metabolism in WML.…”

Common Shared Pathogenic Aspects of Small Vessels in Heart and Brain Disease

“…Different pharmacologic stressors such as adenosine and dipyridamole are employed to achieve maximal hyperemia [12], during which high-resolution perfusion CMR can demonstrate a microvascular dysfunction by quantifying the blood-flow distribution across myocardial layers [97]. Likewise, advanced magnetic resonance imaging techniques and PET scans can provide relevant clues to the presence and severity of cerebral SVD [98,99]. Traditionally, computed tomography (CT) imaging has been used to detect morphologic lesions without evaluating their functional consequences.…”