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PubMed1999

Function of the cerebellum in Parkinsonian rest tremor and Holmes' tremor.

We describe a patient who developed Parkinson's disease (PD) 17 years after resection of his right cerebellum because of a Lindau tumor. He showed a classic 4.3-Hz resting tremor on the left side but a 3.1-Hz resting, postural, and intention tremor on the right side compatible with midbrain tremor (Holmes' tremor). We conclude that the generator of the tremor in PD cannot be located within the olivocerebellar loop. The cerebellum, however, seems to modulate the tremor frequency of parkinsonian rest tremor and may prevent the rest tremor from transforming into a postural and goal-directed tremor.

Adult↗
PubMed1987

Immunogold staining of microtubules in resting and activated platelets.

A circumferential microtubule is known to support the discoid form of resting platelets, but its fate following exposure of the cells to aggregating agents is uncertain. The present study has employed an immunocytochemical approach to follow the fate of the circumferential microtubule in activated platelets. Monoclonal antibodies to tubulin and to vinculin and a polyclonal antibody to actin were incubated with isolated microtubule coils and stained with staphylococcal protein A coupled to immunogold in order to test their specificity. Thin sections of glycolmethacrylate embedded platelets before and after exposure to thrombin for 15, 30 and 60 s were stained with antibodies to tubulin and actin. Immunogold particles showed a high specificity for isolated MT coils stained for tubulin, modest intensity for actin, and none for vinculin. Gold particles were randomly distributed in thin sections of resting and activated platelets stained for actin. Immunogold was limited to the circumferential microtubule in resting platelets and constricted coils in thrombin-activated cells. The number of gold particles in areas of cytoplasm away from microtubules in platelets stained with antitubulin antibody increased slightly following thrombin activation, but the change was not significant. Results support the concept that microtubule coils supporting the discoid form of resting platelets do not dissolve following exposure of the cells to potent agonists.

Actins↗
PubMed2004

Working capacity and resting energy expenditure after ileal pouch-anal anastomosis.

BACKGROUND: The aim was to evaluate the working capacity and resting energy expenditure in patients who had undergone restorative proctocolectomy. METHODS: Of 72 patients operated on between April 1990 to September 1998, 51 were eligible and 38 participated in the study. Resting energy was assessed by indirect calorimetry, and working capacity by ergospirometry on an exercise bicycle. RESULTS: The median functional score was 2 (range 0-7). Oxygen uptake during rest was reduced for men compared with predicted values. The corresponding values for women were in keeping with predicted values. The median working capacity was 96 (range 59-102) per cent for women and 91 (range 51-113) per cent for men, compared with reference values of maximum workload based on age, height and sex. There was no correlation between functional score and any other variable measured. CONCLUSION: Patients who have undergone restorative proctocolectomy for ulcerative colitis have normal resting energy expenditure and working capacity.

Adult↗
PubMed1980

Comparative effect of intravenous dipyridamole and sublingual nitroglycerin on coronary hemodynamics and myocardial metabolism at rest and during atrial pacing in patients with coronary artery disease.

The effects of intravenous dipyridamole (20 mg) and sublingual nitroglycerin (0.6 mg) were compared at rest and during rapid atrial pacing in patients with significant coronary obstruction. Dipyridamole, which had no significant effect on resting systolic blood pressure, caused a significant increase in coronary sinus flow (CSF) and reduction of coronary vascular resistance (CVR) and arterial-coronary sinus oxygen difference (AO2CSO2 delta), whereas nitroglycerin reduced resting systolic pressure but had no significant effect on CSF, CVR, or AO2-CSO2 delta. Although theses effects of dipyridamole and nitroglycerin on resting systolic pressure, CSF, CVR, and AO2-CSO2 delta were qualitatively similar during rapid atrial pacing, the onset of chest pain and ischemic ECG changes occurred at a lower heart rate following dipyridamole (136 +/- 5 beats/min) than following nitroglycerin (149 +/- 6 beats/min, p less than 0.01). However, maximal double product and myocardial oxygen consumption achieved during pacing were similar following both dipyridamole and nitroglycerin and were less than control pacing values. Coronary dilatation following dipyridamole appears to reduce tolerance to pacing-induced ischemia probably by maldistribution of coronary flow away from ischemic myocardium. Nitroglycerin differs from dipyridamole by improving tolerance to pacing; however, this difference appears to be due to systemic vasodilator effects of nitroglycerin rather than to enhancement of flow to ischemic myocardium.

Aged↗
PubMed1989

Hemodynamic and antianginal effects during rest and exercise of intravenous isradipine, a new dihydropyridine calcium antagonist.

In an open randomized study, hemodynamic and antianginal effects of nifedipine and the new dihydropyridine derivative isradipine were compared in patients with stable, angiographically confirmed coronary heart disease. Right heart hemodynamics, systemic arterial blood pressure, ECG, and drug plasma concentrations were measured before medication at rest and exercise, after infusions of increasing doses at rest, and again after treatment at rest and exercise. A linear relationship between serum concentrations and cumulated dosages was obtained for both drugs. At rest, both drugs significantly increased cardiac output and heart rate. The reduction of arterial blood pressure was significantly greater after isradipine (systolic from 148 +/- 3 to 104 +/- 3 mmHg; diastolic from 90 +/- 4 to 58 +/- 2 mmHg) than after nifedipine (systolic 149 +/- 6 to 125 +/- 4 mmHg; diastolic 92 +/- 4 to 76 +/- 3 mmHg). The minimal effective plasma level of isradipine regarding blood pressure reduction was estimated at 5 ng/ml (nifedipine: 10-25 ng/ml). During exercise both medications significantly reduced mean pulmonary artery pressure (isradipine: 40 +/- 3 to 20 +/- 1 mmHg, nifedipine: 37 +/- 4 to 22 +/- 1 mmHg), pulmonary artery wedge pressure (isradipine: 23 +/- 3 to 10 +/- 1 mmHg, nifedipine 24 +/- 3 to 14 +/- 1 mmHg), and diastolic arterial pressure (isradipine: 103 +/- 3 to 73 +/- 4 mmHg, nifedipine: 99 +/- 3 to 91 +/- 2 mmHg), whereas systolic pressure was reduced by only isradipine (189 +/- 4 to 147 +/- 5 mmHg). Neither medication significantly changed electrocardiographic ST depression during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Diagnostic value of technetium-99m-MIBI as a myocardial perfusion imaging agent: comparison of long and short intervals between rest and stress injections.

To assess the diagnostic value of technetium-99m-MIBI (99mTc-MIBI) as a myocardial perfusion imaging agent, and if rest and exercise scans could be performed on the same day, 21 patients with coronary artery disease were studied. Qualitative planar 201-thallium (201Tl) scans, coronary angiography, or both were also performed (median between studies 11 days). In 10 patients an injection of 740 mBq of 99mTc-MIBI at stress was followed by a second injection of 740 mBq at rest 24 h later (long interal) (LI). In 11 patients injection of 370 mBq at rest was followed 3 h later by an injection of 740 mBq at stress (short interval) (SI). Exercise scans were performed to similar maximal work load (LI = 6.6 +/- 1.8 METs; SI = 6.3 +/- 1.7 METs; 201Tl = 6.8 +/- 1.2 METs; p = NS) and double product (LI = 19551 +/- 7370; SI = 19900 +/- 6797; 201Tl = 19965 +/- 5282; p = NS). Overall, 99mTc-MIBI and 201Tl agreed in 92% of the patients tested and in 165 of 180 (92%) left ventricular segments in both 99mTc-MIBI protocols using short and long intervals between injections. In 15 patients with significant stenosis, 99mTc-MIBI correctly identified 13 patients (sensitivity of 87%). Thus, 99mTc-MIBI is a useful imaging agent with similar diagnostic value as 201Tl. In spite of its lack of myocardial redistribution, 99mTc-MIBI rest and exercise scans performed on the same day seem to have a similar concordance rate with 201Tl as when performed on separate days.

Adult↗
PubMed2000

Rest and exercise hemodynamics before and after valve replacement--a combined Doppler/catheter study.

BACKGROUND: Hemodynamic improvement is a common finding following valve replacement. However, despite a normally functioning prosthesis and normal left ventricular ejection fraction, some patients may show an abnormal hemodynamic response to exercise. METHODS: In a combined catheter/Doppler study, rest and exercise hemodynamics were evaluated in 23 patients following aortic (n = 12) (Group 1) or mitral valve (n = 11) (Group 2) replacement and compared with preoperative findings. Patient selection was based on absence of coronary artery disease and left ventricular failure as shown by preoperative angiography. Cardiac output, pulmonary artery pressure, pulmonary capillary pressure, and pulmonary resistance were measured by right heart catheterization, whereas the gradient across the valve prosthesis was determined by Doppler echocardiography. Postoperative evaluation was done at rest and during exercise. The mean follow-up was 8.2 +/- 2.2 years in Group 1 and 4.2 +/- 1 years in Group 2. RESULTS: With exercise, there was a significant rise in cardiac output in both groups. In Group 1, mean pulmonary pressure/capillary pressure decreased from 24 +/- 9/18 +/- 9 mmHg preoperatively to 18 +/- 2/12 +/- 4 mmHg postoperatively (p < 0.05), and increased to 43 +/- 12/30 +/- 8 mmHg with exercise (p < 0.05). The corresponding values for Group 2 were 36 +/- 12/24 +/- 6 mmHg preoperatively, 24 +/- 7/17 +/- 6 mmHg postoperatively (p < 0.05), and 51 +/- 2/38 +/- 4 mmHg with exercise (p < 0.05). Pulmonary vascular resistance was 109 +/- 56 dyne.s.cm-5 preoperatively, 70 +/- 39 dyne.s.cm-5 postoperatively (p < 0.05), and 70 +/- 36 dyne.s.cm-5 with exercise in Group 1. The corresponding values for Group 2 were 241 +/- 155 dyne.s.cm-5, 116 +/- 39 dyne.s.cm-5 (p < 0.05), and 104 +/- 47 dyne.s.cm-5. There was a significant increase in the gradients across the valve prosthesis in both groups, showing a significant correlation between the gradient at rest and exercise. No correlation was found between valve prosthesis gradient and pulmonary pressures. CONCLUSION: Exercise-induced pulmonary hypertension and abnormal left ventricular filling pressures seem to be a frequent finding following aortic or mitral valve replacement. Both hemodynamic abnormalities seem not to be determined by obstruction to flow across the valve prosthesis and may be concealed, showing nearly normal values at rest but a pathologic response to physical stress.

Adult↗
PubMed1984

Genesis of resting microglia in the gray matter of mouse hippocampus.

The genesis of resting microglia in the gray matter of mouse hippocampus was studied by 3H-thymidine autoradiography in combination with electron microscopy. Newborn mice were injected with 3H-thymidine singly or repeatedly at different postnatal stages, and killed shortly after the injection or after various intervals. Tissue specimens of the hippocampus at CA1 and CA2 were processed for light and electron microscopic autoradiography. The results showed that at least 91% of glial cells in the stratum radiatum of the hippocampus are produced after birth. About three-fourths of astroglia in this area are produced before the sixth postnatal day, and a larger part of resting microglia are formed after the ninth postnatal day. Morphological transition can be traced from either proliferating cells in the stratum radiatum at late postnatal days to resting microglia, or from those in early postnatal days to astroglia. A continuous morphological transition was observed between the proliferating cells at the late postnatal days (microglial production period) and those at the early postnatal days (astroglial production period). The latter retain some fine structural characteristics similar to small glioblasts in the subependymal layer. These findings strongly suggest that resting microglia, as well as astroglia, are derived from glioblasts, and are of neurectodermal origin.

Animals↗
PubMed1990

The activation of resting lymphocytes is accompanied by the biogenesis of lysosomal organelles.

The degradative activity of lymphocytes plays by important role in a number of essential immune functions. In the present study we have examined how the activation of resting lymphocytes, by the mitogen concanavalin A (Con A), affects three major components of the lysosomal compartment: the lysosomal enzyme beta-glucuronidase (Gus); an integral lysosomal membrane protein (LAMP-1); and the mannose 6-phosphate receptor (MPR) which directs lymphocyte enzyme transport. Resting T cells were found to contain only very low levels of these proteins, but they were actively synthesized by, and far more abundant in, stimulated lymphoblasts. Although the lysosomal antigens did not have a distinct cytoplasmic localization in the resting lymphocytes, in the activated T lymphoblasts they were present in several highly developed intracellular structures, including the rough endoplasmic reticulum and the Golgi complex. Furthermore, in these latter cells Gus was also found to be accumulated within the lumen of large vesicles which we characterized as lysosomes by the presence of LAMP-1 at the periphery and by the absence of MPR. Subcellular fractionation confirmed that these organelles were present in the activated lymphocytes only, and not in the resting T cells. Our results demonstrate that lymphocyte activation is accompanied by the synthesis of the enzymic and structural components of the lysosomal compartment which are sorted and assembled into distinct organelles in the activated cell.

Animals↗
PubMed1994

A novel anti-rat CD18 monoclonal antibody triggers lymphocyte homotypic aggregation and granulocyte adhesion to plastic: different intracellular signaling pathways in resting versus activated thymocytes.

We have raised a monoclonal antibody (mAb), NG2B12, directed against rat CD18, capable of inducing lymphocyte homotypic adhesion and granulocyte adherence to plastic. NG2B12-induced aggregation is temperature sensitive and requires metabolic energy, an intact cytoskeleton and the presence of Mg2+, but is independent of protein synthesis. Ca2+ is not only dispensable but exerts a suppressive effect on the NG2B12-induced adhesion. The adhesion is readily observed in thymocytes and concanavalin A blasts of thymocytes and splenocytes but is very weak in resting spleen and lymph node cells. NG2B12 also enhances phorbol 12-myristate 13-acetate (PMA)-induced aggregation in an additive fashion. The NG2B12-induced homotypic adhesion is mediated by LFA-1. mAb against ICAM-1 completely inhibited the induced adhesion of activated cells but inhibited only partially and in a time-dependent manner the adhesion of resting thymocytes. The activation of protein phosphatases 1 and 2A (as assessed by the use of okadaic acid) is necessary for the NG2B12-induced adhesion of both resting and activated thymocytes. In contrast, H-7 (an inhibitor of protein kinase C and A), substantially suppressed the adhesion of resting thymocytes, whereas W-7 (an inhibitor of calmodulin-dependent protein kinase) inhibited the adhesion of activated thymocytes. NG2B12 induces both adherence to plastic and homotypic aggregation of granulocytes; the events being blocked by anti-CD18 (WT.3) and anti-CD11b/CD11c (OX-42) mAb, augmented by okadaic acid and not modified by H-7 and W-7. Additionally, we have demonstrated that NG2B12 and PMA employ distinct intracellular signaling pathways in inducing adhesion of both thymocytes and granulocytes.

Animals↗
PubMed2004

Loss or mismatch of MHC class I is sufficient to trigger NK cell-mediated rejection of resting lymphocytes in vivo - role of KARAP/DAP12-dependent and -independent pathways.

A prediction from the "missing self" hypothesis is that down-regulation of MHC class I on resting hematopoietic cells should be sufficient to make them susceptible to NK cell killing. Using a method enabling kinetic and quantitative assessments of NK cell-mediated rejection responses in vivo, we here show that resting hematopoietic cells from beta(2)-microglobulin-deficient (beta(2)m(-/-)) mice were rapidly rejected in unmanipulated C57BL/6 (B6) mice. In situations of allelic MHC class I mismatches rejection occurred but required longer time. beta(2)m(-/-) donor cells pre-activated with concanavalin A were more efficiently eliminated compared to resting cells, as were MHC(-) tumor cells. When recipient mice were pretreated with an IFN inducer to activate NK cells, rejection was also enhanced. The signaling adaptor KARAP/DAP12 was dispensable for rejection of beta(2)m(-/-) cells (lacking MHC) but critical for rejection of BALB/c cells (mismatched MHC) in unmanipulated B6 recipients. In contrast, B6 recipients with pre-activated NK cells rejected BALB/c cells in a KARAP/DAP12-independent fashion. Loss or mismatch of MHC class I in resting cells was thus sufficient to convey susceptibility to NK cell rejection. However, activation of the effector or the target enhanced rejection and shifted the balance between different signaling pathways involved.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Human resting CD16-, CD16+ and IL-2-, IL-12-, IL-15- or IFN-alpha-activated natural killer cells differentially respond to sphingosylphosphorylcholine, lysophosphatidylcholine and platelet-activating factor.

The phosphorylcholine-containing lipid lysophosphatidylcholine (LPC) is abundant in the bloodstream, whereas sphingosylphosphorylcholine (SPC) and platelet-activating factor (PAF) highly accumulate at inflamed sites. Utilizing RT-PCR, flow cytometry and immunoblot analyses, we show for the first time that ovarian cancer G protein-coupled receptor 1, the receptor for SPC, is expressed in IL-2-, IL-12- and IL-15-activated but not in resting CD16-, resting CD16+ or IFN-alpha-activated NK cells. Similarly, G2 accumulation and PAF receptor are variably expressed in these subsets of NK cells. SPC, LPC and PAF differentially induce the chemotaxis of resting and activated NK cells. In the chemotaxis assay, it is observed that resting CD16-CD56bright and CD16+CD56dim cells predominantly respond to LPC, whereas activated NK cells, regardless of the sort of stimulus, robustly respond to PAF. SPC is also a potent chemoattractant for IL-2-, IL-12- and IL-15- but not for IFN-alpha-activated NK cells. Further analysis shows that, depending on the cytokine pattern of NK cell activation, phosphorylcholine-containing lipids differentially affect IFN-gamma secretion by these cells. Our results provide one possible explanation for the tissue compartmentation of NK cells and their ability to secrete IFN-gamma. Furthermore, these results may provide novel information regarding NK cell regulation during inflammation.

Cell Cycle Proteins↗
PubMed2007

Altered functional connectivity in early Alzheimer's disease: a resting-state fMRI study.

Previous studies have led to the proposal that patients with Alzheimer's disease (AD) may have disturbed functional connectivity between different brain regions. Furthermore, recent resting-state functional magnetic resonance imaging (fMRI) studies have also shown that low-frequency (<0.08 Hz) fluctuations (LFF) of the blood oxygenation level-dependent signals were abnormal in several brain areas of AD patients. However, few studies have investigated disturbed LFF connectivity in AD patients. By using resting-state fMRI, this study sought to investigate the abnormal functional connectivities throughout the entire brain of early AD patients, and analyze the global distribution of these abnormalities. For this purpose, the authors divided the whole brain into 116 regions and identified abnormal connectivities by comparing the correlation coefficients of each pair. Compared with healthy controls, AD patients had decreased positive correlations between the prefrontal and parietal lobes, but increased positive correlations within the prefrontal lobe, parietal lobe, and occipital lobe. The AD patients also had decreased negative correlations (closer to zero) between two intrinsically anti-correlated networks that had previously been found in the resting brain. By using resting-state fMRI, our results supported previous studies that have reported an anterior-posterior disconnection phenomenon and increased within-lobe functional connectivity in AD patients. In addition, the results also suggest that AD may disturb the correlation/anti-correlation effect in the two intrinsically anti-correlated networks.

Aged↗
PubMed1977

Surface exposure of glycosaminoglycans in resting, growing and virus transformed 3T3 cells.

Glycosaminoglycans (GAG's) were released by trypsin from the surface of cultured mouse cells (3T3) in two different growing states: during log-growth phase and during resting due to serum starvation. Doubly labelled molecules from resting cells were compared with those from growing as well as from trnsformed cells. Reproducible differences in the elution pattern during ion exchange chromatography and in susceptibility to specific hydrolytic enzymes have been demonstrated: the GAGs pattern of growing normal cells is similar to the pattern of the cells transformed by either Polyoma or SV-40 viruses and very different from the pattern of resting cells. Growing and transformed 3T3 show a relatively low amount of trypsin removable heparan sulphate (HS) and a relatively high amount of hyaluronic acid (HA) while resting cells exhibit an opposite ratio between the two GAG'S. The lowering of HS and the increase of HA in the cell coat is therefore suspected to be more dependent upon growth than upon transformation.

Animals↗
PubMed1985

Transcription of ribosomal RNA is differentially controlled in resting and growing BALB/c 3T3 cells.

Shortly after serum-deprived BALB/c 3T3 fibroblasts are stimulated to grow in medium containing 10% calf serum, the RNA polymerase I activity in permeabilized cells shows a two-fold increase over the values observed in either serum-deprived or density-inhibited resting cells. Inhibition of protein synthesis by pactamycin or cycloheximide specifically reduces the enhanced RNA polymerase I activity in serum-stimulated cultures without affecting the values in resting cells. On the other hand, inhibition of rRNA processing by the nucleoside analogs 5-fluoruridine and toyocamycin decreases the rate of 45S rRNA transcription in serum-stimulated cells but has no effect on the values found in resting cultures. These data suggest that the regulation of rRNA transcription occurs by two different mechanisms, depending on the growth state of the cell. One mechanism, in serum-stimulated cells, is dependent on a continuous protein synthesis and a correct 45S rRNA processing; the other, in resting cells, is independent of these two parameters.

Adenosine↗
PubMed1982

Effects of thyroxine on transmembrane resting potentials of skeletal muscle cells in culture.

The effect of thyroxine (T4) was studied on the transmembrane resting potential (Em) of rat skeletal muscle cells in culture. In agreement with previous studies, we found the Em of developing muscle cells to increase with age from Day 3 to Day 7 or 8, at which time a plateau is reached. The values of Em we obtained (-65 to -75 mV) were 15-20 mV higher than those (-50 to -55 mV) reported by others. Treatment of mature myotubes with T4 resulted in a significant increase in resting Em. There was only a slight difference between T4-treated and control cells with regard to the relation between extracellular K+ concentration and resting Em. Within 20-30 min of exposure to ouabain (10(-4)--10(-3)M) resting Em of both T4-treated and control cells had fallen to about the same value. This effect was reversible. Thus, T4 stimulates the activity of an electrogenic Na/K-ATPase in the membrane of cultured skeletal muscle cells.

Animals↗
PubMed2001

Rigidity decreases resting tremor intensity in Parkinson's disease: A [(123)I]beta-CIT SPECT study in early, nonmedicated patients.

Tremor is one of the clinical hallmarks of Parkinson's disease (PD). Although it is accepted that other classic symptoms of PD such as rigidity and bradykinesia result from a degeneration of the nigrostriatal system and subsequent reduction in striatal dopamine, the pathophysiology of resting tremor remains unclear. The majority of recent single photon emission computed tomography (SPECT) and positron emission tomography (PET) studies, using various radioligands, demonstrated significant correlation between striatal radioligand bindings and the degree of parkinsonian symptoms such as rigidity and bradykinesia, but not tremor. We investigate the relationship between the degeneration of the nigrostriatal pathway and the appearance of resting tremor, taking into account the possible interference of rigidity with the resting tremor. Thirty early and drug-naïve PD patients were examined. Tremor and rigidity of the arms were assessed using UPDRS, and the power of tremor was estimated using spectral analysis of tremor peaks. [(123)I]beta-CIT SPECT was used to assess degeneration of the dopaminergic system in PD patients. A comparison between asymmetry indices showed that in terms of both tremor and rigidity, the most affected arm corresponded significantly with the contralateral striatum, having the largest reduction in radioligand binding. Furthermore, tremor power accounted for a significant part of variance in the contralateral striatum, suggesting a relationship between this PD symptom and the degeneration of the dopaminergic system. Further, the degree of tremor was reduced with increasing rigidity. However, correcting for the influence of rigidity, the significant contribution of tremor in the variance in the contralateral striatal [(123)I]beta-CIT binding disappeared. When the confounding influence of rigidity is taken into account, no significant direct relationship between dopaminergic degeneration and the degree of tremor could be found. Other pathophysiological mechanisms should be similarly investigated in order to further our understanding of the origin of resting tremor in PD.

Adult↗
PubMed2003

Importance of k-space trajectory in echo-planar myocardial tagging at rest and during dobutamine stress.

Hybrid fast gradient echo/echo-planar imaging (FGRE-EPI) can be used to increase temporal resolution, enhance tag contrast, and/or decrease scan time for breathhold myocardial tagging. However, off-resonance effects and motion can lead to local phase discontinuities in FGRE-EPI raw data when a conventional interleaved bottom-up k-space trajectory is used. These discontinuities can be particularly problematic for myocardial tagging, where the image energy is not only concentrated near the k-space origin, but is also concentrated in multiple spectral peaks centered throughout k-space. In this study, tag distortion artifacts in FGRE-EPI tagging due to off-resonance and velocity-induced phase discontinuities were characterized at rest and dobutamine stress, and the flyback and gradient moment smoothing (GMS) methods were shown to reduce these artifacts. For the specific parameters used in this study, flyback and GMS resulted in improved image quality at rest and stress, increased myocardium-tag contrast-to-noise ratio (11.4 +/- 2.1 vs. 10.0 +/- 2.9, P < 0.01 at rest; 11.1 +/- 1.8 vs. 8.1 +/- 2.4, P < 0.01 at stress), and reduced full width at half maximum of the tag profile (3.6 vs. 3.8 pixels at rest; 4.0 vs. 5.1 pixels at stress) compared to the conventional trajectory. A limitation of the improved trajectory is a parameter-dependent decrease in data acquisition efficiency. For the specific imaging protocol used, the repetition time of the improved trajectory increased by 36% compared to the conventional trajectory.

Artifacts↗

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