ABSTRACT
To evaluate the validity of exercise tolerance test [ETT] with treadmill exercise in the diagnosis and follow-up of ischaemic heart disease [IHD], taking myocardial perfusion scan [MPS] as standard. Retrospective, validation study. Nuclear Medical Centre [NMC] Armed Forces Institute of Pathology [AFIP], Rawalpindi, Pakistan, from 1 January to 31 December 2009. One hundred and nineteen patients [88 males, 31 females], referred for MPS; were selected through non-probability, consecutive sampling. Patients of all ages and gender, fit to undertake treadmill exercise, were included. Patients with contraindications to ETT, like unstable angina, conduction abnormalities, etc., or those who had taken a beta blocker within the preceding 24 hours, were excluded. ETT through treadmill exercise was done, followed by MPS with single photon emission computed tomography [SPECT] technique, using Thallium-201 or Technetium-99 m 2-methoxy-isobutyl-isonitrile [MIBI]. ETT was interpreted as positive or negative for ischaemia, with borderline changes considered positive. MPS was interpreted as positive or negative for ischaemia. Validity of ETT was evaluated in terms of sensitivity [Sn], specificity [Sp], and positive and negative predictive value [PPV and NPV], taking MPS as standard. Sensitivity of ETT was found to be 77.5% and specificity was 43.6%. PPV was 73.8% and NPV was 48.6%. Out of a total [n] of 119 patients, true positive [TP] cases were 62, true negative [TN] 17, false positive [FP] 22 and false negative [FN] 18. ETT is an acceptably sensitive but non-specific test for evaluating myocardial ischaemia, with adequate PPV but low NPV, when validating it against MPS. Replacing the MPS with ETT, in the diagnosis and follow-up of IHD, is thus, not prudent. ETT can be useful as a screening test
ABSTRACT
To determine an association between chronic tobacco use and changes in cerebral perfusion through semi-quantitative scintigraphic assessment employing metastable Technetium-99 labelled hexa-methyl propylene amine oxime single photon emission computed tomography [Tc-99m HMPAO SPECT]. Design: Case-control study. Place and duration of study: The study was conducted at the Department of Medical Sciences, Pakistan Institute of Engineering and Applied Sciences [PIEAS], Nilore, Islamabad, from Oct 2001 to May 2002. Regional cerebral perfusion in 48 chronic tobacco users was evaluated, utilising a normal database created by HMPAO brain scans of 20 non-tobacco users. Subjects were classified into chronic tobacco users and non-tobacco users through the use of the smoking index [SI]. [Smoking Index = Number of years of tobacco use x Number of cigarettes smoked per day]. SI value of 100 was taken as the cut-off value. Regions of interest [ROIs] were declared hypoperfused or hyperperfused if their percentage perfusion values relative to the average perfusion per pixel of the whole slice under evaluation did not fall within + 2 standard deviation [SD] of the mean regional perfusion in the corresponding ROI, in the normal control group. Result: Chronic tobacco users showed 164 hypoperfused ROIs [6.57%] and 138 hyperperfused ROIs [5.53%] out of 2496 ROIs assessed, whereas the normal controls showed only 15 hypoperfused [1.44%] and 27 hyperperfused [2.60%] ROIs out of 1040 ROIs assessed [P < 0.001]. Cerebral perfusion in chronic tobacco users was found to be significantly decreased compared to the non-tobacco users
ABSTRACT
To find the cause of neonatal jaundice in patients of up to 1 year of age, referred to Nuclear Medical Centre, AFIP Rawalpindi. Patients of jaundice up to 1 year of age referred by paediatricians from Military Hospitals were subjected to radionuclide cholescintigraphy at Nuclear Medical Centre, AFIP, Rawalpindi. The pattern noted was that 41% cases were scintigraphically positive for biliary atresia, 37% cases were found to be negative for it. Sixteen percent of the cases showed scintigraphic evidence of parenchymal liver disease and the possibility of biliary atresia could not be completely ruled out in these patients. Interestingly 6% of the cases were noted to be inconclusive though they were suffering from jaundice. The female to male ratio were 1:1.5, 1:6, and 1:1.6 for biliary atresia, negative for biliary atresia and parenchymal liver disease respectively. The cause of neonatal jaundice in most cases was biliary atresia and the frequency in males was higher as compared to female patients