T1ρ MRI of Alzheimer's disease

Abstract

Alzheimer's disease (AD) is the most common form of dementia in the elderly. Classic symptoms of the disease include memory loss and confusion associated with the hallmark neuro-pathologic lesions of neurofibrillary tangles (NFT) and senile plaques (SP) and their sequelae, gray matter atrophy. Volumetric assessment methods measure tissue atrophy, which typically follows early biochemical changes. An alternate MRI contrast mechanism to visualize the early pathological changes is T 1ρ (or "T-1-rho"), the spin lattice relaxation time constant in the rotating frame, which determines the decay of the transverse magnetization in the presence of a "spin-lock" radio-frequency field. Macromolecular changes (in plaques and tangles) that accompany early AD are expected to alter bulk water T 1ρ relaxation times. In this work, we measure T 1ρ MRI on patients with clinically diagnosed AD, MCI and in age-matched ognitively normal control subjects in order to compare T 1ρ values with changes in brain volume in the same regions of the brain and demonstrate that T 1ρ can potentially constitute an important biomarker of AD.

Quantitative T1ρ imaging using phase cycling for B0 and B1 field inhomogeneity compensation

“…The loss of proteoglycan in cartilage is a characteristic event in the early stages of osteoarthritis, and the T 1ρ relaxation has the potential to follow this process [1][2][3][4][5]. Besides this, T 1ρ imaging is also found useful in a number of other applications [6][7][8][9][10][11][12]. In T 1ρ imaging, the spins are tipped into the transverse plane in one axis.…”

T1rho (T1ρ) MR imaging in Alzheimer’ disease and Parkinson’s disease with and without dementia

“…We have previously demonstrated that an alternate MRI contrast mechanism, T 1 ρ (T1rho), which is the spin lattice relaxation time constant in the rotating frame, can distinguish between AD and age-matched controls [5, 10]. In biological tissues, T 1 ρ relaxation may have contributions from several interactions.…”

Differentiation of brain tumor-related edema based on 3D T1rho imaging

“…T1ρ has been studied to a limited extent in several neuroimaging applications including the evaluation of ischemia [11,23,24], neurodegenerative disorders [17,18], demyelinating disease [20,21], animal models of brain tumor [12–14,25], and response to gene therapy [15,16]. Although the exact mechanisms governing T1ρ relaxation are not fully understood, several factors proposed to influence T1ρ include scalar coupling, dipole–dipole interactions, and chemical exchange processes [26].…”

“…T1ρ can be used to probe macromolecular interactions and has been shown to reflect normal aging as well as pathologic changes in tissue protein and pH content [9–11]. A small number of published reports have shown potential applications of T1ρ neuroimaging to evaluate tumor boundaries [12–16], neurodegenerative disease [17–19], demyelination [20,21], psychiatric disease [22], and acute cerebral ischemia [11,23,24]. …”