Panacea Journal of Medical Sciences

Analysis of CT perfusion parameters in the setting of cerebral ischemic stroke

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Article Type : Null

Author Details: Ayyamperumal Balaji, Peter Babu, Vanitha K

Volume : 5

Issue : 3

Online ISSN : 2348-7682

Print ISSN : 2249-8176

Article First Page : 130

Article End Page : 136

Abstract

The study was carried out to evaluate the different parameters of cerebral blood perfusion in ischemic areas and to determine the most appropriate parameter to identify infarcted and non-infarcted zone. A prospective study in patients with hemispheric stroke to The Stroke Service over a period of two years was undertaken. Initial CT with CT perfusion and MRI diffusion-weighted imaging was done. Total of 47 cases were studied. NIHSS score was determined. Renal function was done. Time since the onset of stroke as told by the patient or relative was recorded. CT perfusion studies were performed using a 4-slice CT scanner (TOSHIBA) with CT perfusion software. MRI was performed with a 1.5-T clinical whole-body unit. MR DWI images were visually analysed to match the sections on PCT images. The PCT maps and MR images were co registered manually. Statistical analysis used ROC. Mean age was 55.9 years. The Mean NIHSS score was 15.9. Mean CT scan time was 10. 2 hours after symptom onset. The thresholds for rCBF (54%) and rMTT (142%) found would allow differentiation of core and pneumbra. We found a longer MTT with more severe ischemia, in accordance with the central volume principle that states that MTT is inversely related to the perfusion pressure. This statistical analysis of the parameters confirms that rMTT is a better separator of viable and nonviable tissue than is rCBV. Furthermore, higher sensitivity and accuracy were obtained for rMTT than for rCBV and MTT maps. Relative MTT, with an optimal threshold of 142%, provided the most accurate prediction of the final infarct size.

Keywords: CT perfusion, Diffusion MRI, Cerebral blood flow, Cerebral blood volume, Core, Pneumbra, Mean transit time.

 

Doi No:-10.18231