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Biomedical subjects

D Atkinson

Publications and source records attributed to D Atkinson.

At least 19 recordsLinked to original sources
PubMed2000

Sampling and reconstruction effects due to motion in diffusion-weighted interleaved echo planar imaging.

Subject motion during diffusion-weighted interleaved echo-planar imaging causes k-space offsets which lead to irregular sampling in the phase-encode direction. For each image, the k-space shifts are monitored using 2D navigator echoes, and are shown to lead to a frequent violation of the Nyquist condition when an ungated sequence is used on seven subjects. Combining data from four repeat acquisitions allows the Nyquist condition to be satisfied in all but 1% of images. Reconstruction of the irregularly-sampled data can be performed using a matrix inversion technique. The repeated acquisitions make the inversion more stable and additionally improve the signal-to-noise ratio. The resultant isotropic diffusion-weighted images and average apparent diffusion coefficient (ADC) maps show high resolution and enable clear localization of a stroke lesion. Residual ADC artifacts with a slow spatial variation are observed and assumed to originate from non-rigid pulsatile brain motion. Magn Reson Med 44:101-109, 2000.

Artifacts↗
PubMed2000

Beating the grog: an evaluation of the Tennant Creek liquor licensing restrictions.

OBJECTIVE: To review the effectiveness of, and community attitudes towards, increased restrictions on the availability of alcohol in Tennant Creek. METHOD: Estimates of quarterly per capita consumption of pure alcohol by persons aged > or = 15 years, admissions data from the local hospital, women's refuge and sobering up shelter, and police data on detentions in custody and common offences were compared for the 12 months prior and 24 months subsequent to the introduction of the restrictions. A random sample survey of residents aged > or = 18 years was conducted to ascertain attitudes towards the restrictions. RESULTS: Over the two years following the introduction of the restrictions, there was a reduction of 19.4% in annual per capita consumption of pure alcohol. This was accompanied by declines in: hospital admissions for acute alcohol-related diagnostic related groups; and persons taken into police custody and the proportions of offences reported on Thursdays. A majority of survey respondents was in favour of retaining or strengthening the existing restrictions. CONCLUSIONS: The restrictions were effective in reducing alcohol consumption and acute related harm and had the support of the majority of people in Tennant Creek. On the basis of this evidence, the NT Liquor Commission made a decision to retain them. Restrictions do not provide a simple answer to the problems associated with excessive alcohol consumption. However, they can be an effective part of a broad public health strategy to deal with such problems.

Adolescent↗
PubMed1999

Automatic compensation of motion artifacts in MRI.

Patient motion during the acquisition of a magnetic resonance image can cause blurring and ghosting artifacts in the image. This paper presents a new post-processing strategy that can reduce artifacts due to in-plane, rigid-body motion in times comparable to that required to re-scan a patient. The algorithm iteratively determines unknown patient motion such that corrections for this motion provide the best image quality, as measured by an entropy-related focus criterion. The new optimization strategy features a multi-resolution approach in the phase-encode direction, separate successive one-dimensional searches for rotations and translations, and a novel method requiring only one re-gridding calculation for each rotation angle considered. Applicability to general rigid-body in-plane rotational and translational motion and to a range of differently weighted images and k-space trajectories is demonstrated. Motion artifact reduction is observed for data from a phantom, volunteers, and patients.

Algorithms↗
PubMed1999

Water temperature influences the shoaling decisions of guppies, Poecilia reticulata, under predation threat.

In previous experiments, we found antipredator behaviours in female Trinidadian guppies to be influenced by water temperature. To distinguish between hypotheses suggested to explain these observations, we examined the effect of an increase in water temperature on the choice of shoal size of individual female guppies, in the absence and presence of predation threat from a confined cichlid. At 22 degrees C, guppies showed no significant preference for either of two shoal sizes of female guppies, although other responses indicated a reaction to the threat. At 26 degrees C, females chose to shoal with the smaller group when the predator was absent, but, once threatened, switched to a strong preference for the larger group. Variation in preference between individuals was quite high in all treatments, and was somewhat lower for guppies under threat in warmer water, although not significantly so. Our evidence indicates that guppies in warmer water behave as if they are at greater risk of predation, but only when under threat. Temperature-dependent increases in predation risk from ectothermic piscivores could result from less efficient escape responses and from greater vulnerability because of increased foraging activity. We suggest that selection favouring guppies displaying an optimal balance between foraging and antipredator behaviours should act more strongly at higher temperature. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Effects of standing on cerebrovascular resistance in patients with idiopathic orthostatic intolerance.

PURPOSE: Patients with idiopathic orthostatic intolerance often have debilitating symptoms on standing that are suggestive of cerebral hypoperfusion despite the absence of orthostatic hypotension. SUBJECTS AND METHODS: We evaluated the effects of graded head-up tilt on cerebral blood flow as determined by transcranial Doppler measurements in 10 patients with idiopathic orthostatic intolerance (nine women, one man, 22 to 47 years) and nine age- and sex-matched control subjects. RESULTS: In patients, mean (+/- SD) arterial pressure at 0 degrees head-up tilt was 90 +/- 11 mm Hg and was well maintained at all tilt angles (90 +/- 11 mm Hg at 75 degrees). In controls, mean arterial pressure was 85 +/- 7 mm Hg at 0 degrees and 82 +/- 11 mm Hg at 75 degrees head-up tilt. There was a substantial decrease in peak velocity with increasing tilt angle in patients (28% +/- 10%) but not in controls (10% +/- 10% at 75 degrees, P <0.001). Similarly, mean velocity decreased 26% +/- 13% in patients and 12% +/- 11% in controls (P = 0.01). With increasing head-up tilt, patients had a significantly greater increase in regional cerebrovascular resistance than controls. CONCLUSIONS: In patients with idiopathic orthostatic intolerance, peak and mean middle cerebral artery blood flow velocity decreased in response to head-up tilt despite well sustained arterial blood pressure. These observations indicate that in this group of patients, regulation of cerebrovascular tone may be impaired and might therefore be a target for therapeutic interventions.

Adult↗
PubMed1999

Postpartum health in a Dhaka slum.

This study examines the health, nutritional status, and health care seeking behaviour of a community based sample of 122 postpartum women from an urban slum in Dhaka, Bangladesh. It describes a physically impoverished environment in which malnutrition is serious, and non-trivial morbid episodes as a consequence of childbirth are very common. Malnutrition was found to be widespread: about one-quarter of the study mothers were short in stature, measuring 145cm or less in height; over two-thirds of the women weighed <45 kg; and a similar proportion had a BMI of <20. Based on mid-upper arm circumference, an overwhelming majority (96%) suffered from some degree of malnutrition. During the first 6 weeks postpartum over three-quarters of the women reported a non-trivial illness. The frequency of reported illnesses was significantly associated with both increasing age and parity. Despite severe poverty, most of the women reporting illnesses (71%) received some form of health care from a wide range of western and traditional health care providers, with Traditional Birth Attendants (TBAs) and unqualified western care providers being the most frequently utilised. This study highlights the plight of these women in a precarious environment and shows how their health is compromised by cultural and political constraints. We conclude that while the burden of postpartum morbidity is very high, the incorporation of traditional practitioners and unqualified western care providers into maternal health training programs, together with efforts to empower women, could be effective in improving the health status of mothers in this marginalised and fragmented community. To achieve this outcome, a clearly articulated and integrated approach to development in slum communities is required.

Adolescent↗
PubMed1999

Bubble contrast echocardiography in detecting pulmonary arteriovenous shunting in children with univentricular heart after cavopulmonary anastomosis.

OBJECTIVES: We sought to compare bubble contrast echocardiography and pulmonary angiography in detecting pulmonary arteriovenous malformation (PAVM) in children with cavopulmonary anastomosis (CPA), and to examine anatomic and physiologic variables associated with the development of PAVM. BACKGROUND: Development of PAVM in patients with CPA may cause profound cyanosis. Pulmonary arteriovenous malformation has been traditionally diagnosed by pulmonary angiography with reported incidence of 20% to 25% in patients with CPA. METHODS: Fourteen patients (age 1.1 to 12.6 years) with any forms of CPA and normal pulmonary venous drainage formed the study population. All patients underwent cardiac catheterization and pulmonary angiography. Bubble contrast echocardiographic studies were performed with injection of 10 ml of agitated saline solution into branch pulmonary arteries. Transthoracic echocardiograms using an apical view were performed to assess the appearance of bubble contrast in the systemic ventricles. We compared the results of pulmonary angiograms and contrast echocardiograms, and findings of contrast echocardiograms between lungs with hepatic venous blood flow and lungs without hepatic venous blood. RESULTS: Ten of the 14 patients (71%) had positive contrast echocardiographic studies, compared with three (21%) detected by pulmonary angiograms (p = 0.01). No difference was found in pulmonary artery pressure, transpulmonary gradient or presence of heterotaxy syndrome between patients with positive contrast echocardiographic studies and patients with negative studies. However, patients with positive contrast echocardiograms tended to have lower oxygen saturation (81%) and higher hemoglobin (16.4 g/dl) compared with patients with negative studies (88% and 14.7 g/dl, p = 0.10 and p = 0.18 respectively). Patients with Glenn shunt or unidirectional Fontan had higher incidence of PAVM (10/11) compared with patients with classic or lateral tunnel Fontan (0/3, p = 0.01). All 12 lungs with no perfusion of hepatic venous blood had positive contrast echocardiographic studies. Lungs with no hepatic venous blood flow were more likely to develop PAVM compared with lungs with hepatic venous blood flow (12/12 and 3/16 respectively, p < 0.01). CONCLUSIONS: Bubble contrast echocardiography is more sensitive in detecting PAVM compared with pulmonary angiography. The prevalence of PAVM in patients with CPA may be much higher than what had been reported previously. Lungs with no hepatic venous blood flow are more likely to develop PAVM than lungs with hepatic venous blood flow.

Angiography↗
PubMed1999

Controlled trial of two formulations of cromolyn sodium in the treatment of asthmatic patients > or = 12 years of age. Intal Study Group.

STUDY OBJECTIVES: This multicenter, randomized, double-blind, placebo-controlled, parallel study compared the efficacy and safety of the hydrofluoroalkane (HFA) formulation of cromolyn sodium metered-dose inhaler (MDI) with the chlorofluorocarbon (CFC) formulation in asthmatic patients > or = 12 years old over a 12-week period. DESIGN: Stable asthmatics using only currently marketed cromolyn sodium and as-needed inhaled beta2-agonists were randomly assigned to treatment with HFA cromolyn sodium, CFC cromolyn sodium, or placebo, administered as two inhalations (2 mg) qid for 12 weeks. Prior to randomization, all patients were required to meet minimum symptom and/or pulmonary function test criteria after discontinuation of cromolyn sodium. Efficacy was assessed by changes in daily symptom scores, albuterol use, peak expiratory flow, pulmonary function measurements, and overall opinions of effectiveness. RESULTS: A total of 280 patients in 29 centers were randomly assigned to treatment with HFA cromolyn sodium (n = 94), CFC cromolyn sodium (n = 91), or placebo (n = 95). Patients treated with the HFA formulation of cromolyn sodium demonstrated a 28 to 33% improvement over placebo for all symptom scores (p < 0.05) and a 35% improvement over placebo in the use of albuterol MDI (p < 0.05). The patients' opinions of overall effectiveness favored HFA cromolyn sodium (p = 0.011) and CFC cromolyn sodium (p = 0.006) over placebo. The investigators' opinions indicated a statistically significant difference favoring CFC cromolyn sodium compared with both placebo (p < 0.001) and HFA cromolyn sodium (p = 0.042). No statistically significant differences existed among groups in the incidence of treatment-related adverse events. CONCLUSION: The HFA formulation of cromolyn sodium MDI is a well-tolerated and effective treatment for asthma patients > or = 12 years old. The safety and efficacy profile of the HFA formulation is comparable to that of the CFC formulation.

Administration, Inhalation↗
PubMed1998

Thermodynamic analysis of human plasma apolipoprotein C-1: high-temperature unfolding and low-temperature oligomer dissociation.

Thermal and chemical unfolding of lipid-free apolipoprotein C-1 (apoC-1), a 6-kDa protein component of very low density and high-density lipoproteins, was analyzed by far-UV CD. In neutral 1 mM Na2HPO4 solutions containing 6-7 micrograms/mL protein, the apoC-1 monomer is approximately 30% alpha-helical at 0-22 degrees C and unfolds reversibly from about 22-80 degrees C with Tm = 51 +/- 3 degrees C and van't Hoff enthalpy delta Hv(Tm) = 19 +/- 3 kcal/mol. The apparent free energy of the monomer stabilization determined from the chemical unfolding at 0 degree C, delta G(0 degree C) = 2.8 +/- 0.8 kcal/mol, decreases by about 1 kcal/mol upon heating to 25 degrees C. A small apparent heat capacity increment suggests the absence of a substantial hydrophobic core for the apoC-1 molecule. At pH 7, increasing apoC-1 concentration above 10 micrograms/mL leads to self-association and formation of additional alpha-helices that unfold upon both heating and cooling from room temperature. The CD data indicate that the high-temperature transition reflects a complete monomer unfolding and the low-temperature transition reflects oligomer dissociation into stable monomers. This suggests the importance of hydrophobic interactions for apoC-1 self-association. Close proximity between the high- and low-temperature transitions and the absence of a plateau in the chemical unfolding curves recorded from oligomeric apoC-1 indicate marginal oligomer stability and suggest that in vivo apoC-1 transfer is mediated via the complexes with other apolipoproteins and/or lipids.

Acetates↗
PubMed1998

Effects of temperature on anti-predator behaviour in the guppy, Poecilia reticulata.

Warmer environmental temperatures are likely to increase the frequency of predator-prey interactions in ectothermic animals, and therefore might be expected to influence anti-predator behaviour. In a first experiment, groups of recently fed guppies, placed in a novel environment, schooled significantly more closely at 26 degrees than at 22 degreesC. Changes in two of three measures of schooling tendency over time indicated that aggregation increased during the trial periods, probably as a result of increased familiarity within the experimental groups. In a second experiment, pairs of female guppies were tested at 22 degrees and 26 degreesC, with and without predation threat from a confined cichlid. From multifactor analysis of 18 behaviour types, temperature was shown to affect behavioural time budgets profoundly, particularly in the presence of the predator. At the higher temperature, a shift occurred from inactive anti-predator behaviours and minimal foraging activity towards active predator inspection-related behaviours and a much higher level of feeding. Guppies in the warmer water might have been physically able to school more closely as a result of faster swimming ability, or might have used temperature as a cue indicating higher potential predation risk, and aggregated accordingly. The use of temperature as a source of information about the biotic environment is discussed. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1998

Exogenous nitric oxide enhances neutrophil cell death and DNA fragmentation.

Inhaled nitric oxide (NO) is an important new therapeutic agent used to treat pulmonary arterial hypertension in a variety of disease states. However, the effects of NO on cells in the lung are uncertain. Previously, we have shown that NO gas depresses neutrophil oxidative cell function and increases neutrophil cell death. The purpose of this in vitro study was to determine the mechanism of neutrophil death. We hypothesized that NO hastened cell death by inducing apoptosis. To mimic the clinical environment of patients with respiratory failure, we also studied the effects of hyperoxia on neutrophil cell viability and apoptosis. Isolated human neutrophils were exposed to 80% O2 (O2), NO at 20 ppm in room air (NO/RA), 20 ppm NO blended with 80% O2 (NO/O2), or RA alone (control) for 2 to 24 h. Experiments were repeated with NO concentrations of 5 and 50 ppm and with 20 ppm in the presence of superoxide dismutase (SOD). Neutrophils were also incubated in the absence or presence of neutrophil stimulant fMLP (10 nM). Neutrophil cell viability was measured by fluorescence viability/cytotoxicity assay. Neutrophil apoptosis was assessed by cell death detection ELISA for histone-associated DNA fragments, TdT transferase-mediated fluorescence-labeled dUTP nick end labeling (TUNEL) assay, and DNA fragmentation gel electrophoresis. NO/O2-exposed neutrophils showed decreased viability at 2 h (31.7 +/- 3.7%, mean % viability +/- SD) compared with control (94.7 +/- 4.7%), O2 (75.6 +/- 9.3%), and NO/RA (62.8 +/- 14.9%; P < 0.05 by ANOVA; n = 9). Although control neutrophils demonstrated marked apoptosis at 24 h, there was no significant apoptosis at 2, 4, or 6 h (P < 0.001 by Kruskal-Wallis, n = 20) as assessed by ELISA and TUNEL assays. When compared with RA controls at 2 h, neutrophils exposed to NO/O2 showed significantly more apoptosis (292% of control, range: 106 to 2,488%, P < 0.001 by ANOVA and Kruskal-Wallis) but not with exposure to NO/RA or O2 alone. These findings were confirmed by TUNEL assay (n = 4, P < 0.05). NO/ RA and NO/O2-exposed neutrophils demonstrated both evidence of necrosis and enhanced DNA fragmentation at 2 h by gel electrophoresis (n = 2). Fifty parts per million NO produced similar findings, but exposure to 5 ppm NO did not induce significant DNA fragmentation. Coincubation with SOD inhibited NO/ O2-associated apoptosis, suggesting peroxynitrite contributed to cell death. Stimulation with fMLP did not alter apoptosis induced in neutrophils exposed to NO/RA or NO/O2. We conclude that exogenous NO gas, at clinically relevant concentrations under hyperoxic conditions, induces cell death in neutrophils in part by enhancing DNA fragmentation.

Apoptosis↗
PubMed1997

Automatic correction of motion artifacts in magnetic resonance images using an entropy focus criterion.

We present the use of an entropy focus criterion to enable automatic focusing of motion corrupted magnetic resonance images. We demonstrate the principle using illustrative examples from cooperative volunteers. Our technique can determine unknown patient motion or use knowledge of motion from other measures as a starting estimate. The motion estimate is used to compensate the acquired data and is iteratively refined using the image entropy. Entropy focuses the whole image principally by favoring the removal of motion induced ghosts and blurring from otherwise dark regions of the image. Using only the image data, and no special hardware or pulse sequences, we demonstrate correction for arbitrary rigid-body translational motion in the imaging plane and for a single rotation. Extension to three-dimensional (3-D) and more general motion should be possible. The algorithm is able to determine volunteer motion well. The mean absolute deviation between algorithm and navigator-echo-determined motion is comparable to the displacement step size used in the algorithm. Local deviations from the recorded motion or navigator-determined motion are explained and we indicate how enhanced focus criteria may be derived. In all cases we were able to compensate images for patient motion, reducing blurring and ghosting.

Artifacts↗
PubMed1996

Thermal unfolding of human high-density apolipoprotein A-1: implications for a lipid-free molten globular state.

Apolipoprotein A-1 (apoA-1) in complex with high-density lipoprotein is critically involved in the transport and metabolism of cholesterol and in the pathogenesis of atherosclerosis. We reexamined the thermal unfolding of lipid-free apoA-1 in low-salt solution at pH approximately 7, by using differential scanning calorimetry and circular dichroism. At protein concentrations <5 mg/ml, thermal unfolding of apoA-1 is resolved as an extended peak (25 degrees C-90 degrees C) that can be largely accounted for by a single reversible non-two-state transition with midpoint Tm 57 +/- 1 degree C, calorimetric enthalpy deltaH(Tm)= 200 +/- 20 kcal/mol (1 kcal = 4.18 kJ), van't Hoff enthalpy deltaHv(Tm) approximately 32.5 kcal/mol, and cooperativity deltaHv(Tm)/deltaH(Tm) approximately 0.16. The enthalpy deltaH(Tm) can be accounted for by melting of the alpha-helical structure that is inferred by CD to constitute approximately 60% of apoA-1 amino acids. Farand near-UV CD spectra reveal noncoincident melting of the secondary and tertiary structural elements and indicate a well-defined secondary structure but a largely melted tertiary structure for apoA-1 at approximately 37 degrees C and pH 7. This suggests a molten globular-like state for lipid-free apoA-1 under near-physiological conditions. Our results suggest that in vivo lipid binding by apoA-1 may be mediated via the molten globular apolipoprotein state in plasma.

Apolipoprotein A-I↗
PubMed1996

High- and low-temperature unfolding of human high-density apolipoprotein A-2.

Human plasma apolipoprotein A-2 (apoA-2) is the second major protein of the high-density lipoproteins that mediate the transport and metabolism of cholesterol. Using CD spectroscopy and differential scanning calorimetry, we demonstrate that the structure of lipid-free apoA-2 in neutral low-salt solutions is most stable at approximately 25 degrees C and unfolds reversibly both upon heating and cooling from 25 degrees C. High-temperature unfolding of apoA-2, monitored by far-UV CD, extends from 25-85 degrees C with midpoint Th = 56 +/- 2 degrees C and vant Hoff's enthalpy delta H(Th) = 17 +/- 2 kcal/mol that is substantially lower than the expected enthalpy of melting of the alpha-helical structure. This suggests low-cooperativity apoA-2 unfolding. The apparent free energy of apoA-2 stabilization inferred from the CD analysis of the thermal unfolding, delta G(app)(25 degrees) = 0.82 +/- 0.15 kcal/mol, agrees with the value determined from chemical denaturation. Enhanced low-temperature stability of apoA-2 observed upon increase in Na2HPO4 concentration from 0.3 mM to 50 mM or addition of 10% glycerol may be linked to reduced water activity. The close proximity of the heat and cold unfolding transitions, that is consistent with low delta G(app)(25 degrees), indicates that lipid-free apoA-2 has a substantial hydrophobic core but is only marginally stable under near-physiological solvent conditions. This suggests that in vivo apoA-2 transfer is unlikely to proceed via the lipid-free state. Low delta H(Th) and low apparent delta Cp approximately 0.52 kcal/mol.K inferred from the far-UV CD analysis of apoA-2 unfolding, and absence of tertiary packing interactions involving Tyr groups suggested by near-UV CD, are consistent with a molten globular-like state of lipid-free apoA-2.

Apolipoprotein A-II↗
PubMed1996

MR imaging of surgical complications of systemic-to-pulmonary artery shunts.

Patients with a systemic-to-pulmonary artery shunt and positive findings on traditional imaging modalities such as chest X-ray, echocardiography, or cardiac angiography often can benefit from additional noninvasive imaging with magnetic resonance imaging (MRI). Diagnostic dilemmas encountered include: pseudoaneurysms, contained fluid collection (seroma) surrounding a shunt, and stenosis of the shunt anastomoses. MRI studies using traditional cardiac-triggered spin-echo (SE) imaging and the newer breathhold MRI studies with k-space segmented gradient-recalled echo (GRE) imaging can greatly help resolve diagnostic dilemmas. By combining different MR imaging techniques it becomes possible to clearly distinguish between pseudoaneurysms and seroma, to exclude an active leak and to sometimes visualize the distal anastomosis with more precision than conventional angiography. MRI is often able to add information needed for clinical decision making prior to surgical repair.

Adolescent↗
PubMed1996

Fluid-attenuated inversion recovery (FLAIR) for assessment of cerebral infarction. Initial clinical experience in 50 patients.

BACKGROUND AND PURPOSE: Our aim was to evaluate fluid-attenuated inversion recovery (FLAIR) sequence in the diagnosis of cerebral infarction with MRI. METHODS: A retrospective review was undertaken of 50 consecutive MRI studies ordered for suspected cerebrovascular accident. All studies included FLAIR and rapid acquisition with relaxation enhancement (RARE) T2-weighted spin-echo sequences. The two sequences were compared independently by four observers at two different institutions. Detectability of lesions and image quality were scored. RESULTS: Overall, FLAIR sequences proved superior in 10 patients, detecting acute cortical infarcts missed with RARE spin-echo technique in five patients. In five additional patients, improved characterization of chronic infarction and improved detection of microangiopathic deep hemispheric changes were observed. One brain stem infarct was missed with the FLAIR sequence. CONCLUSIONS: FLAIR offers advantages in detection of acute infarcts affecting the cortical ribbon, is a useful, rapid adjunct to conventional T2-weighted spin-echo sequences, and has the potential to replace these in the future.

Artifacts↗
PubMed1996

Fluid-attenuated inversion recovery (FLAIR): clinical prospectus of current and future applications.

A relative weakness of the traditional spin-echo technique, and particularly of the newer "FAST" or "TURBO" spin-echo sequences, has been diminished conspicuousness of lesions affecting the peripheral cortical mantle or those located in the periventricular region. This is a consequence of partial volume effects and high cerebrospinal fluid (CSF) signal adjacent to pathologic regions. Fluid-attenuated inversion recovery (FLAIR) is a magnetic resonance imaging (MRI) sequence that produces strong T2 weighting, suppresses the CSF signal, and minimizes contrast between gray matter and white matter. This effect produces images with significantly increased lesion-to-background CSF contrast and enhances the visibility of lesions as well as their detectability, particularly in the peripheral subcortical and periventricular regions. Applications are evolving, though preliminary reports highlight the superiority of FLAIR in the evaluation of infarction, multiple sclerosis, metastatic disease, tuberous sclerosis, and, possibly, subarachnoid hemorrhage. Early reports also address the application of FLAIR to imaging of the spinal cord. Modified versions of FLAIR are currently being developed; these modifications will further shorten acquisition times and eliminate pulsation artifacts. FLAIR may ultimately supplant conventional spin-echo imaging in routine MR screening of the brain.

Brain Diseases↗