Stable xenon versus radiolabeled microsphere cerebral blood flow measurements in baboons.

Abstract

Regional cerebral blood flow was simultaneously determined using the stable xenon computed tomographic and the radioactive microsphere techniques over a wide range of blood flow rates (less than 10-greater than 300 ml/100 g/min) in 12 baboons under conditions of normocapnia, hypocapnia, and hypercapnia. A total of 31 pairs of determinations were made. After anesthetic and surgical preparation of the baboons, cerebral blood flow was repeatedly determined using the stable xenon technique during saturation with 50% xenon in oxygen. Concurrently, cerebral blood flow was determined before and during xenon administration using 15-microns microspheres. In Group 1 (n = 7), xenon and microsphere determinations were made repeatedly during normocapnia. In Group 2 (n = 5), cerebral blood flow was determined using both techniques in each baboon during hypocapnia (PaCO2 = 20 mm Hg), normocapnia (PaCO2 = 40 mm Hg), and hypercapnia (PaCO2 = 60 mm Hg). Xenon and microsphere values in Group 1 were significantly correlated (r = 0.69, p less than 0.01). In Group 2, values from both techniques also correlated closely across all levels of PaCO2 (r = 0.92, p less than 0.001). No significant differences existed between the slopes or y intercepts of the regression lines for either group and the line of identity. Our data indicate that the stable xenon technique yields cerebral blood flow values that correlate well with values determined using radioactive microspheres across a wide range of cerebral blood flow rates.

Recommendations for Imaging of Acute Ischemic Stroke

“…[291][292][293][294] Studies in animal models and humans with acute cerebral ischemia indicate that XeCT provides accurate CBF values with mild to severe levels of ischemia. 259,293,295 …”

Guidelines and Recommendations for Perfusion Imaging in Cerebral Ischemia

“…There is a high degree of correlation between CBF values acquired with the XeCT technique and 133 Xe, 110 iodoantipyrine, 111 and microsphere embolization [112][113][114] in prospective, comparative studies using animal models in tightly controlled laboratory experiments. Although the stability of the flow value in a single voxel of 10 mm 3 is poor, the reliability of the data from an ROI of Ͼ100 voxels is approximately 12%.…”

Quantitative assessment of regional cerebral blood flows by perfusion CT studies at low injection rates: a critical review of the underlying theoretical models

“…The cerebral vessels turned out to be normal. b Stable-xenon CT study obtained 5 min prior to the perfusion CT led to an rCBF map, which can be considered as a reference for comparison, since stable-xenon CT has been validated as an accurate and quantitative technique of rCBF measurement [79,80,81] Fig. 2 Four images of the perfusion CT series realized in this patient, consisting of 25 sequential axial 10-mm CT sections obtained every 2 s at these two adjacent levels due to multidetector array technology, with a total acquisition time of 50 s. Acquisition parameters were 80 kVp and 200 mAs.…”