ABSTRACT
BACKGROUND: ECG -gated myocardial perfusion imaging is a sensitive test for diagnosis of ischemia as well as scarred myocardium. It provides additional information on global and regional myocardial contractile function. A number of methods are available to calculate left ventricular volumes and ejection fractions, which depends on various technical and patients specific factor. OBJECTIVE: This study was carried out to measure effect of reconstruction filter in calculations of left ventricularend diastolic volume (EDV) and end systolic volume (ESV) and left ventricular ejection fraction (LVEF) from 99mTc-sestamibi myocardial perfusion imaging. MATERIALS AND METHODS: 99mTc-sestamibi-gated SPECT myocardial perfusion imaging was performed in 90 patients. Studies were reconstructed with Butterworth and Metz filters. RESULTS: Mean ejection fraction with Butterworth and Metz filter are 64.3 and 64.2, respectively. Mean EDV is for Butterworth and Metz filters are 77.3 and 78.5 ml, respectively. While ESV was 36.49 and 36.63 ml, stroke volume calculated was 41.54 and 42 ml for Butterworth and Metz filters, respectively. Pearsons's correlation coefficients between results calculated with Metz and Butterworth filters were 0.994 for ESV, 0.996 for EDV, 0.966 for LVEF and 0.925 for SV. Student 't' test was applied on the data and no significant difference was noted between parameter estimated by Butterworth or Metz filter. CONCLUSION: This study shows that difference of filter application has no significant effect in computing left ventricular function parameters.
ABSTRACT
There is a paucity of regional cerebral blood flow studies on Japanese encephalitis (JE) with none of these studies describing brain perfusion abnormalities in all three stages of the disease. In this communication we report the changes noted in brain perfusion as detected by single photon emission tomography (SPET), in the acute, subacute and chronic stages of JE. Between December 2000 and March 2006, 31 patients, 19 men and 12 women, mean age 49 y, range 6-64 y of various stages of JE underwent brain perfusion SPET. Tauhese patients were at the following stages of the disease: acute stage, five patients, subacute stage 17 and chronic stage nine . The acute stage was considered as up to seven days from the onset of symptoms, the subacute, from seven to 56 days and any duration beyond 56 days was considered as the chronic stage. In the acute stage all five patients demonstrated focal areas of hyperperfusion involving mainly the thalamus. Additionally, bilateral thalami involvement was noted in three, frontal lobe involvement in four and parietotemporal hyperperfusion in three of these patients. In the subacute stage group, hypoperfusion of the thalamus was noted in all patients while frontoparietal hypoperfusion in seven patients. In the chronic stage group, hypoperfusion of thalamus was noted in four, one patient demonstrated additional occipital lobe hypoperfuion whereas normal perfusion was noted in the remaining five patients. In conclusion, the brain perfusion abnormalities observed depended on the stage of the disease. In the acute stage there was focal hyperperfusion to sites of the brain where JE virus is considered to replicate. In the subacute stage focal hypoperfusion was found to be possibly due to virus induced damage of cellular protein synthesis and in the chronic stage perfusion returns to normal due to regeneration of cellular organelles. Our results also confirm the high frequency of thalamic involvement in JE.