PubMed Health⌕ Search

Biomedical subjects

M M Rehani

Publications and source records attributed to M M Rehani.

17 recordsLinked to original sources
PubMed2005

Effect of reduction in tube current on reader confidence in paediatric computed tomography.

BACKGROUND: Computed tomography (CT) contributes significantly to the total radiation dose derived from medical imaging in children. As the number of CT examinations increases there is renewed interest in possible ways to minimize such radiation. AIM: To study the effect of decremental reduction in tube current settings on structural resolution and on reader confidence in being able to reach a final diagnosis. MATERIALS AND METHODS: The study involved spiral CT of children aged 0-13 years. CT performed at reduced mA settings (60-75, 76-90 and 91-130 mA for thoracic, abdominal and pelvic examinations, and 76-90 and 91-130 mA for cranial examinations) were compared with similar investigations at conventional settings (180-240 mA). Images were scored by two blinded readers for structural resolution and diagnostic confidence. Structural resolution was scored on a binary (adequate or not) scale for six structures each in cranial, thoracic and pelvic examinations and for eight structures in abdominal studies, and reader confidence was scored on a four-point scale as 25-100%. Scores from the two readers were averaged for comparison in subgroup analyses. RESULTS: Reduction of tube current settings to 75-90 mA for thoracic, abdominal and pelvic examinations and to 90-130 mA for cranial examinations was not associated with any significant deterioration in image quality. The number of scans considered satisfactory were comparable even at 60-75 mA, although the total relative scores for structural resolution at this setting were lower. CONCLUSION: Tube current settings can be significantly reduced in all paediatric age groups, in all regions. In younger children the impact of such reduction in tube current is likely to be greater. Cranial scans are more sensitive to such reductions as compared to thoracic or abdominopelvic examinations.

Adolescent↗
PubMed1982

Transport studies and enzyme assays in mice infected with human Giardia lamblia.

It is well established that Giardia infection causes malabsorption. However, the precise mechanism of such a malabsorption is not known. To investigate this, transport studies, using the tissue accumulation technique, were carried out in mice infected with G. lamblia obtained from human stools. There was a significant fall in the transport of D-glucose, L-alanine and glycine in the infected animals compared with the controls. Kinetics of the D-glucose and glycine transport system were examined by measuring the tissue uptake in the presence of different concentrations of the substrate. For glucose, the affinity constant (Km) for the transport site was the same (4 . 37mM) in normal and infected animals but the maximal transport rate (V max) was considerably reduced in infected animals (158 . 7 mu moles/hr/g tissue) compared with (357 . 1 microgram moles/hr/g tissue) in controls. Results with glycine were similar; the Km was similar in control and infected animals (5 . 7 mM) whereas the V max was reduced in infected animals (27 . 02 microgram moles/hr/g tissue) compared with controls (45 . 5 micrograms moles/hr/g tissue). Analysis of the intestinal enzymes showed a significant decrease in the levels of brush border sucrase, lactase and alkaline phosphatase in infected animals; the cellular enzymes, LDH, GOT and GPT remained unaffected. The observed aberrations in the transport functions and brush border enzymes suggest that G. lamblia causes malabsorption by damaging the epithelial membrane of the enterocyte.

Alanine↗
PubMed1980

Value and limitations of testicular scanning by in vivo labelling of RBC with 99mTc.

When a scrotal affection cannot be diagnosed confidently by correlation of clinical history and physical examination, testicular scanning with 99mTc is a useful adjunct diagnostic modality. In vivo labelling of red blood cells with 99mTc was achieved by prior oral administration of 200 mg of stannous chloride. This helped to obtain satisfactory scintigraphy with a rectilinear scanner. This procedure was found to be useful in the adult with recent tender testicle in whom the torsion of the testis could not be clinically differentiated from epididymo-orchitis. Another area of scan's valuable clinical application was in the early diagnosis of testicular abscess in patients with epididymo-orchitis not responding immediately to antibiotic therapy. The study also proved to be a useful, non-invasive method for follow-up assessment of a case of torsion of the testis where detorsion and orchiopexy was performed as well as in case of rupture of a testis after orchiorrhapy.

Erythrocytes↗
PubMed1980

Site of Tc-99m binding to the red blood cell: concise communication.

The increasing interest in the use of Tc-99m-labeled red blood cells encourages exploration into the site and mechanism of binding of Tc-99m to the RBC components. The components isolated from the labeled red cells were the lipid and protein of the membrane, heme, and the alpha and beta chains of the globin. The binding occurs mainly to the protein moiety, and preferentially to the beta chain of the globin, where the specific activity was found to be 28 +/- 6 times that of the alpha chain. The mechanism of binding is discussed. The role of heme in the binding is not clear.

Binding Sites↗
PubMed1980

Placental localisation with 99mTc-labelled red blood cells.

The accuracy of placental localisation by radioisotopic scanning using 99mTc-labelled red blood cells has been estimated in 20 patients. The results have been correlated with the findings at delivery by direct and indirect methods. The accuracy of results regarding upper and lower segment insertion of the placenta was 90% in the present study.

Erythrocytes↗
PubMed1980

Evaluation of a simpler technique for in-vivo labelling of red blood cells with 99mTc.

The efficiency of labelling red blood cells with intravenously administered 99mTcO4, by prior oral administration of stannous chloride dihydrate, has been evaluated. Optimum labelling occurred 1 hr after the oral dose of 200 mg of SnCl2.2 H2O and 20 min after the intravenous injection of 99mTcO4. The mechanism of labelling has been shown to be diffusion of 99Tc through the cell membrane followed by binding to haemoglobin in the presence of reducing agent. The in-vivo labelling technique has been found to be useful for the diagnosis of an abdominal mass and for static perfusion studies.

Administration, Oral↗
PubMed1979

A new container geometry for better sensitivity in radiometric measurements.

A new two-compartment liquid scintillation vial system for radiometric measurement has been evolved, such that the light attenuation by the inner vial is minimized. The increase in relative efficiency is over 70% better than in an earlier design. The system is compact and versatile, and is suitable for automated, cumulative, or continuous radiometric measurements.

Bicarbonates↗
PubMed1976

A simple and inexpensive clinical whole body counter.

The conventional radioisotope scanner has been used as a whole body counter. The background index of the system is 10.9 counts per minute per ml of sodium iodide crystal. The sensitivity and derived sensitivity parameters have been evaluated and found to be suitable for clinical studies. The optimum parameters for a single detector at two positions above the lying subject have been obtained. It has been found that for the case of 131I measurement it is possible to assay a source located at any point in the body with coefficient of variation less than 5%. To add to the versatility, a fixed geometry for in-vitro counting of large samples has been obtained. The retention values obtained by the whole body counter have been found to correlate with those obtained by in-vitro assay of urine and stool after intravenous administration of 51Cr-albumin.

Background Radiation↗
PubMed1975

Longitudinal and transverse uniformity in clinical whole body counting by an improved technique.

A new technique using a single NaI(Tl) detector (9 cm x 6.3 cm) in two positions and based on the response curves of the detector has been described. Also a different approach to select the energy band was adopted which is helpful in reducing the dependence of counting efficiency on source depth. Various portions of the compton continuum were taken rather than confining to valley and photo-peak. For transverse uniformity it was found that the energy band which gave 50% normalized count rate at half depth would give a resultant flat response with least variation. For longitudinal uniformity the separation between the two positions of the detector need to be nearly equal to the full width at half maximum of the response curve. The response curve coupling technique described here is different from the commonly used technique of iso-response curves.

Chromium Radioisotopes↗