Mean myocardial velocity mapping in quantifying regional myocardial contractile reserve in patients with impaired left ventricular systolic function: Doppler myocardial imaging study.

The aim of this study was to use Doppler myocardial imaging-derived mean myocardial velocity (MMV) at baseline and during low-dose dobutamine stress echocardiography (DSE) to quantify regional contractile reserve of the left ventricle (LV). Sixteen patients (mean age 59 +/- 7 years) with coronary artery disease and regional left ventricular wall motion abnormalities were studied. During each increment of Dobutamine infusion, 6 2-dimensional transthoracic apical images were acquired in standard gray-scale and Doppler myocardial imaging modes at 30 degrees steps over 180 degrees.

Evaluation of isotope proctography in constipated subjects.

Twelve patients with longstanding constipation were examined by isotope proctography. Radio-labelled potato mash was inserted rectally to provoke the urge to defaecate and expulsive manoeuvres were recorded using a Gamma-camera. The method illustrated dynamic alterations in the anorectal angles (ARA) which became more acute on 'squeezing', less so on coughing and more obtuse on straining, and maximally so on evacuation.

A method of computerised isotope dynamic proctography.

Patients with long-standing constipation were examined by radioisotope proctography. A radiolabelled synthetic potato mash was inserted intrarectally and the dynamic changes during simulated defaecation recorded using a gamma-camera. Computer images from the stored data illustrate changes in the anorectal angle and pelvic floor.

The effects of renzapride, a novel prokinetic agent, in diabetic gastroparesis.

Gastric emptying was measured in 9 diabetic patients with autonomic neuropathy (Group 1) and 8 normal controls (Group 2) on 4 occasions after swallowing placebo, 0.5, 1.0 or 2.

Parametric imaging of cerebral vascular reserve. 2. Reproducibility, response to CO2 and correlation with middle cerebral artery velocities.

We report the reproducibility and response to change in end-tidal CO2 of a new method of quantifying regional mean cerebral transit time (MCTT) compared with the reproducibility and CO2 reactivity of middle cerebral artery (MCA) blood flow velocities measured using transcranial Doppler ultrasound. Within the range of end-tidal CO2 which could be achieved in conscious subjects breathing spontaneously, hemispheric MCTT, peak MCA velocity and mean MCA velocity showed a linear relationship with end-tidal CO2. After correction to a standardised end-tidal CO2, the coefficients of variation were 5.

Parametric imaging of cerebral vascular reserves. 1. Theory, validation and normal values.

We describe the theoretical basis and practical details of a method for creating parametric images of the ratio of regional cerebral blood flow (rCBF) to volume (rCBV) from planar gamma-camera images following intravenous injection of any intravascular tracer and after correction for dispersion of the bolus before it arrives at the head. This ratio, which is the most sensitive index of the extent to which perfusion is being maintained by vasodilatation in patients with cerebro-vascular disease, indicates whether the limits of compensation have been, or are in danger of being, exceeded and identifies any ischaemic penumbra. Evidence is provided of the validity of the correction and the accuracy of calculation of the ratio.

Cerebral vascular transit time in Alzheimer's disease and Korsakoff's psychosis and its relation to cognitive function.

The cerebral vascular transit time of 17 patients with pre-senile dementia of the Alzheimer type (ATD), nine abstinent patients with alcoholic Korsakoff's psychosis (KOR), and ten age-matched controls was determined by the bolus intravenous injection of pertechnetate. A gamma camera was used to estimate the median transit time (MTT) of the radioactive bolus in a planar (non-tomographic) projection normal to the vertex. The spread of the bolus arriving at the aortic arch was measured independently by a single external detector over the chest, and correction made for the transit time of this input function in calculating the net MTT for the head.

Smoking delays gastric emptying of solids.

Oesophageal transit and gastric emptying of liquids and solids was measured in eight normal subjects with a single test meal containing In113 labelled water and an omelette labelled with Tc99m sulphur colloid. Each volunteer was studied, basally, whilst continuously smoking, and while chewing nicotine gum. Neither liquid, nor solid oesophageal transit were affected by smoking, or gum.

A comparison of simplified and standard methods for the measurement of glomerular filtration rate and renal tubular function.

Two methods of measuring the clearance of 99Tcm DTPA, OIH and iothalamate were compared with standard techniques of measuring the clearance rates of inulin and sodium para-aminohippurate. The best correlation was between the clearance of subcutaneously injected radiolabelled iothalamate or 99Tcm DTPA and that of inulin. 99Tcm DTPA and 131I OIH clearances measured by a two blood sample technique did not give as good a correlation with inulin and PAH clearances respectively.

Total body neutron activation analysis of calcium: calibration and normalisation.

An irradiation system has been designed, using a neutron beam from a cyclotron, which optimises the uniformity of activation of calcium. Induced activity is measured in a scanning, shadow-shield whole-body counter. Calibration has been effected and reproducibility assessed with three different types of phantom.

Reduction of gastrointestinal protein loss by elemental diet in Crohn's disease of the small bowel.

Seven patients with hypoalbuminaemia and extensive jejunoileal Crohn's disease were treated with an elemental diet for 28 to 56 days. Over this time there was an increase in total plasma proteins from mean of 49.1 to 59.

Measurement of 111in DTPA clearance during radionuclide cisternography.

A new preparation of 111In DTPA for intrathecal administration has been tested and found to be a safe and highly efficacious cisternographic agent. The rate of removal of 111In DTPA from the C.S.