S. Lalith Talagala

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Resting-state, low-frequency (<0.08 Hz) fluctuations of blood oxygenation level-dependent (BOLD) magnetic resonance signal have been shown to exhibit high correlation among functionally connected regions. However, correlations of cerebral blood flow (CBF) fluctuations during the resting state have not been extensively studied. The main challenges of using(More)
BACKGROUND AND PURPOSE Several studies suggest that grey matter involvement may play a role in multiple sclerosis (MS) pathology. Diffusion tensor imaging (DTI) at 3T was used to investigate the presence of damage to the normal-appearing thalamus in MS and its relationship with disability. MATERIALS AND METHODS Twenty-four patients with(More)
A variety of continuous and pulsed arterial spin labeling (ASL) perfusion MRI techniques have been demonstrated in recent years. One of the reasons these methods are still not routinely used is the limited extent of the imaging region. Of the ASL methods proposed to date, continuous ASL (CASL) with a separate labeling coil is particularly attractive for(More)
BACKGROUND AND PURPOSE In vivo detection of cortical lesions in patients with multiple sclerosis (MS) by MR imaging is hampered by several factors. Among them is the low contrast between small cortical lesions and surrounding cortical gray matter offered by present techniques. METHODS T1-weighted 3D spoiled gradient-recalled-echo (SPGR) volumes and 2D(More)
Arterial spin labeling (ASL) perfusion functional magnetic resonance imaging (fMRI) is an attractive alternative to BOLD fMRI. Nevertheless, current ASL fMRI techniques are limited by several factors that hamper more routine applications in humans. One of these factors is restricted brain coverage so that whole-brain ASL fMRI studies have never been(More)
BACKGROUND Major depressive disorder (MDD) has been associated with both dysfunction of the central serotonergic system and abnormal responses to emotional stimuli. We used acute tryptophan depletion (ATD) to investigate the effect of temporarily reducing brain serotonin synthesis on neural and behavioral responses to emotional stimuli in remitted MDD(More)
Pseudo-continuous arterial spin labeling (ASL) can provide best signal-to-noise ratio efficiency with a sufficiently long tag at high fields such as 7 T, but it is very sensitive to off-resonance fields at the tagging location. Here, a robust Prescan procedure is demonstrated to estimate the pseudo-continuous ASL radiofrequency phase and gradients(More)
PURPOSE To demonstrate that the temporal signal-to-noise ratio (SNR) of generalized autocalibrating partially parallel acquisitions (GRAPPA) accelerated echo planar imaging (EPI) can be enhanced and made more spatially uniform by using a fast low angle shot (FLASH) based calibration scan. METHODS EPI of a phantom and human brains were acquired at 3 Tesla(More)
Quantitative phase-contrast magnetic resonance (MR) angiography of the portal vein was prospectively evaluated in 79 fasting patients and 23 healthy volunteers. Images were obtained during a 12-second breath-hold acquisition in the coronal (n = 102) and axial (n = 11) planes. Pathologic correlation was available in 55 of 79 patients and included findings of(More)
The potential teratogenicity of magnetic resonance (MR) field exposure on the early development of the chick embryo was examined. Eggs at four developmental stages within the first 42 hours of incubation were exposed to a static magnetic field of 1.5 T for 6 hours and to 64-MHz radio-frequency field pulses and a switched magnetic field gradient with an(More)