Acquisitions with the spiral-in/out technique result in two separate image timeseries obtained during the spiral-in and spiral-out trajectory. In uniform brain regions the two components have comparable signal and BOLD contrast and can be averaged, but in regions compromised by susceptibility effects where both signal and noise can differ in the two images other combination methods may be more ...

Background First-pass perfusion CMR utilizes accelerated imaging to achieve high spatial resolution and coverage within a small acquisition window. Several compressed sensing (CS) methods have been proposed to accelerate perfusion imaging. However, patient motion due to imperfect breathholding and other factors leads to degraded quality of CS-reconstructed images. We recently demonstrated a CS ...

Background CMR perfusion images demonstrate complex dynamic behavior resulting from signal intensity changes during the first pass of gadolinium as well as motion from imperfect breathholding and gating. Reconstruction algorithms such as kt-PCA and compressed sensing (CS) techniques such as kt-Sparsity and Low-Rankness (kt-SLR) assume that a few spatiotemporal basis functions can model this int...

Background T1 mapping of the left ventricle is routinely performed using Modified Look-Locker Inversion Recovery (MOLLI) [1] in a variety of disease settings [2]. MOLLI requires relatively long breathholds, and consequently sequences of MOLLI images may be misregistered due to respiratory drift. We sought to develop a T1 mapping sequence that would not require breathholding and would not have m...

Breath holding spells are a common and dramatic form of syncope and anoxic seizure in infancy. They are usually triggered by an emotional stimuli or minor trauma. Based on the color change, they are classified into 3 types, cyanotic, pallid, and mixed. Pallid breath holding spells result from exaggerated, vagally-mediated cardiac inhibition, whereas the more common, cyanotic breathholding spell...

Induction and recovery characteristics of isoflurane anaesthesia were compared with halothane anaesthesia during outpatient myringotomy and placement of Sheely ventilation tubes in 101 unpremedicated children. Compared with halothane, isoflurane resulted in prolonged induction times and inferior induction scores due to increased salivation, coughing, breathholding and laryngospasm. However, whe...

1. Block of the phrenic nerves in three normal subjects, produced by injection of lignocaine in the neck, caused alleviation of the thoracic sensation during breath holding and prolonged breath-holding time. 2. Injection of lignocaine in the neck without nerve block had no effect on breath holding sensation or breath-holding time. 3. A patient with a spinal-cord transection at the third cervica...

Breathholding time is usually defined using the procedure of Ogilvie et al. or of Jones and Meade; these procedures depend on knowing when inspiration begins and, for the latter, when it ends. Some alternative procedures do not require this information. With a view to standardizing the measurement, transfer factor of the lungs for carbon monoxide (TLCO) was measured in 18 adults with labile air...

The magnitude and shape of blood oxygen level-dependent (BOLD) responses in functional MRI (fMRI) studies vary across brain regions, subjects, and populations. This variability may be secondary to neural activity or vasculature differences, thus complicating interpretations of BOLD signal changes in fMRI experiments. We compare the BOLD responses to neural activity and a vascular challenge and ...

BACKGROUND The determination of left ventricular ejection fraction using cardiovascular magnetic resonance (CMR) requires a steady cardiac rhythm for electrocardiogram (ECG) gating and multiple breathholds to minimize respiratory motion artifacts, which often leads to scan times of several minutes. The need for gating and breathholding can be eliminated by employing real-time CMR methods such a...