Evaluation of Hemodynamic Perfusion MR Images

Perfusion normally refers to the delivery of blood at the level of capillaries. Hemodynamic perfusion magnetic resonance (MR) imaging has been used in clinics for a series of applications including tumor characterization (histological type diagnosis and grading), diagnosis and the follow up of stroke, and several other disorders. For this study a platform to investigate the theoretical basis of perfusion imaging was developed. Using dynamic measurements of contrast agents in magnetic resonance imaging (MRI) relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT) are calculated. These three parameters are quantized, and displayed as color images for diagnostic and follow up studies. The comparative studies in MR perfusion must address issues such as; image registration, region of interest (ROI) selection, threshold identification and quantization of rCBV, rCBF and rMTT. The evaluation process involved the comparison of the diagnostic capabilities of the three perfusion images (rCBV, rCBF, MTT). Digital subtraction angiography was used as the gold standard in these comparisons. The study group comprises 16 patients with the diagnosis of subarachnoid bleeding and intracranial aneurysms . The proposed cerebral MR perfusion analysis system has been accepted by the radiologists as a useful tool for their perfusion studies and clinical evaluation