Correlation of myocardial perfusion SPECT with invasive and computed tomography coronary angiogram.

BACKGROUND: The consequences of atherosclerosis can be detected by multislice computed tomography (MSCT), invasive coronary angiogram (CAG) and the resultant myocardial ischaemia by myocardial perfusion single photon emission computed tomography (MPS). In this study an attempt is made to compare MSCT with MPS and also to compare the MSCT findings with that of invasive CAG in patients suspected to have coronary artery disease (CAD). MATERIALS AND METHODS: A total of 99 patients suspected to have CAD underwent both MSCT and MPS with (99m)Tc sestamibi. The MSCT studies were classified as having no CAD, significant CAD (>50% diameter stenosis), and insignificant CAD (<50% diameter stenosis). Myocardial perfusion single photon emission computed tomography was reported as normal and reversible ischaemia. In a subgroup of 33 patient invasive CAG was done. RESULTS: In 99 patients, 396 coronaries were evaluated with MSCT and MPS. Coronary artery calcium scoring (CACS) in these patient ranged from 0 to 2200. No CAD was noted in 128 (32%) coronaries but MPS was found abnormal in 9 (7%) coronaries. Insignificant CAD was noted in 169 (43%) coronaries amongst which reversible ischaemia was noted in 23 (14%). Significant CAD was noted in 99 (25%) coronaries of which only 54 (55%) were MPS positive for reversible ischaemia. The MSCT has a negative predictive value (NPV) of 97%. When MSCT was normal, MPS was almost normal, but the reverse was not true. That is when MPS was normal MSCT was not always normal but showed lesion of insignificant obstruction. In the subset of 33 patients, who underwent invasive angiogram, 132 coronaries were evaluated. Coronary angiogram showed 48 coronaries (36%) to have significant CAD (>50% diameter stenosis). Multislice computed tomography correlated well in 46 (84%) with P value of <0.001 (χ(2)-test) but for 9 (16%) showing overestimation due to increased CACS (>800). Myocardial perfusion single photon emission computed tomography was normal in 15 (27%) coronaries. CONCLUSION: Myocardial perfusion single photon emission computed tomography provides functional information of the anatomical lesions and MSCT provides anatomical information. Both are two different diagnostic modalities. The MSCT has high NPV in patients with less likelihood for CAD. When compared with CAG, the correlation with MSCT was good and is useful where the calcium score is low.

Myocardial perfusion single photon emission computed tomography in asymptomatic diabetics.

BACKGROUND: Coronary artery disease (CAD) is the most important cause of mortality in diabetic patients. Diabetes mellitus (DM) due to autonomic neuropathy leads to asymptomatic CAD. Hence, it is important to screen the patients with DM for CAD. AIM: To study the prevalence of asymptomatic CAD by Myocardial Perfuision SPECT (Single Photon Emission Computed Tomography) (MPS) in diabetics. METHODS: This prospective study included 88 asymptomatic patients (58 males and 30 females) of Type 2 DM of more than 5 years duration in the age group of 40-65 years. Risk factors like hypertension, dyslipidemia, smoking, family history of CAD and Body Mass Index > or = 25 kg/sq.m were assessed. All these patients underwent MPS study as two day standard protocol. Thirty eight patients underwent invasive Coronary Angiography (CAG) and stenosis greater than 50% was considered significant. RESULTS: Abnormal perfusion was detected in 38 (43%) diabetics and 4 (11%) controls. A total of 81 perfusion defects were identified (19 fired and 62 reversible). CAG showed significant coronary stenosis in 26 (68.4%), insignificant in 8 (21%) and no stenosis in 4 (10.6%) patients. A total of 114 coronaries were analysed, significant stenosis in 67 (58.8%) coronaries, 21 (18.4%) had insignificant lesions and 26(22.8%) were normal. In comparison to CAG, MPS had sensitivity of 86.6% and specificity of 51%. CONCLUSION: The Myocardial Perfusion SPECT is a sensitive diagnostic tool to identify ischemia in asymptomatic diabetics. MPS can be used as screening test for risk stratification. It has a prognostic value in predicting the outcome of CAD and can be useful for long-term follow up too.

Individual variability in cue-weighting and lexical tone learning.

Speech sound patterns can be discerned using multiple acoustic cues. The relative weighting of these cues is known to be language-specific. Speech-sound training in adults induces changes in cue-weighting such that relevant acoustic cues are emphasized. In the current study, the extent to which individual variability in cue weighting contributes to differential success in learning to use foreign sound patterns was examined. Sixteen English-speaking adult participants underwent a sound-to-meaning training paradigm, during which they learned to incorporate Mandarin linguistic pitch contours into words. In addition to cognitive tests, measures of pitch pattern discrimination and identification were collected from all participants. Reaction time data from the discrimination task was subjected to 3-way multidimensional scaling to extract dimensions underlying tone perception. Two dimensions relating to pitch height and pitch direction were found to underlie non-native tone space. Good learners attended more to pitch direction relative to poor learners, before and after training. Training increased the ability to identify and label pitch direction. The results demonstrate that variability in the ability to successfully learn to use pitch in lexical contexts can be explained by pre-training differences in cue-weighting.

Adsorbing colloid flotation separation and polarographic determination of Mo(VI) in water.

A method is described for the flotation and determination of Mo(VI) in water at ng/ml levels. Mo(VI) is preconcentrated and separated by adsorbing colloid flotation employing aluminium(III) hydroxide as collector and sodium lauryl sulphate as surfactant at pH 5.3 +/- 0.1. The molybdenum content in the froth is estimated by using the catalytic wave of Mo(VI) in the presence of nitrate by charging current compensated d.c. polarography (CCCDCP) or differential pulse polarography (DPP). The effect of variables such as pH, ionic strength, concentration of collector and surfactant, time of stirring and gas flow-rate on the recovery of Mo by flotation is reported. The effects of various cations and anions on the flotation and determination of Mo are studied. This method is employed for the determination of molybdenum in natural fresh water samples.

Determination of free elemental sulphur in some petroleum products.

Uncombined elemental sulphur in petroleum products such as kerosene, diesel, furnace and gear oil has been determined by conversion into copper(I) sulphide at 150-170 degrees . The copper(I) sulphide can be weighed, or its sulphur content determined by the iodimetric method.

A gravimetric procedure for the determination of wet precipitated sulphur, dissolved sulphur, soluble sulphides and hydrogen sulphide.

Elemental sulphur (in wet precipitated form or dissolved in organic solvents) and hydrogen sulphide have been determined gravimetrically at room temperature by conversion into copper sulphide by elemental copper in presence of an organic solvent such as benzene or acetonitrile. Any solvent in which sulphur is soluble can be used. The black copper sulphide formed can be weighed or determined iodometrically. Analysis indicates the black compound to be Cu(1.8)S. This room temperature method is a versatile one-step procedure sensitive to microgram or macro amounts of sulphur. It has been used for determining the solubility of sulphur in tetrahydrofuran and dioxan. The apparent heat of solution indicates that sulphur dissolves in these solvents without any marked solute-solvent interactions.