Vascular depression for radiology: A review of the construct, methodology, and diagnosis

Abstract

Vascular depression (VD) as defined by magnetic resonance imaging (MRI) has been proposed as a unique subtype of late-life depression. The VD hypothesis posits that cerebrovascular disease, as characterized by the presence of MRI-defined white matter hyperintensities, contributes to and increases the risk for depression in older adults. VD is also accompanied by cognitive impairment and poor antidepressant treatment response. The VD diagnosis relies on MRI findings and yet this clinical entity is largely unfamiliar to neuroradiologists and is rarely, if ever, discussed in radiology journals. The primary purpose of this review is to introduce the MRI-defined VD construct to the neuroradiology community. Case reports are highlighted in order to illustrate the profile of VD in terms of radiological, clinical, and neuropsychological findings. A secondary purpose is to elucidate and elaborate on the measurement of cerebrovascular disease through visual rating scales and semi- and fully-automated volumetric methods. These methods are crucial for determining whether lesion burden or lesion severity is the dominant pathological contributor to VD. Additionally, these rating methods have implications for the growing field of computer assisted diagnosis. Since VD has been found to have a profile that is distinct from other types of late-life depression, neuroradiologists, in conjunction with psychiatrists and psychologists, should consider VD in diagnosis and treatment planning.

Keywords: Case reports; Cerebrovascular disorders; Depression; Magnetic resonance imaging; Neuroradiology; Vascular depression; White matter hyperintensities.

Figure 1

Discrimination of vascular depression and non-vascular depression white matter hyperintensities. In non-vascular depression (non-VD) patients, deep white matter hyperintensities are occasionally present, though are few in number and do not begin to converge, as is common in VD patients. Periventricular white matter hyperintensities are more likely to be present in both VD and non-VD patients. VD: Vascular depression; DWMH: Deep white matter hyperintensities; PVWMH: Periventricular white matter hyperintensities.

Figure 2

Semi-quantitative method. Volumetric ratings made using the semi-automated software MRIcro. A: The original grayscale magnetic resonance imaging axial FLAIR image from a representative subject; B: The region of interest (ROI) map created by semiautomatic intensity thresholding; C: The ROI map created by gross manual outlining of hyperintensities; and D: The intersection of (B) and (C) yielding hyperintensities of interest.

Figure 3

Axial slices from a magnetic resonance imaging scan of a vascular depression patient. The highlighted sections are deep white matter hyperintensities, which have been graded as a severity of 2 on the Fazekas rating scale.