Evaluation of regional cerebral blood flow changes on perifocal brain tissue SPECT before and after removal of arteriovenous malformations

Cerebral hemodynamics and metabolism in patients with cerebral arteriovenous malformations: an evaluation using positron emission tomography scanning

“…Intracranial steal phenomenon, venous hypertension, mass effect from the nidus, seizure activity, and neurogenic depressed tissue activity have been suggested as possible causes of this hypoperfusion. 6,8,10,11,15,19,23,25,27 Hyperemic complications sometimes occur after AVM resection. [2][3][4]16,17,28,29 Both NPPB 21 and occlusive hy-peremia 1 have been proposed as underlying mechanisms in severe brain swelling.…”

“…[2][3][4]10,17,[23][24][25][26]28 Most of these were SPECT studies or Xe-enhanced CT studies in which there was acetazolamide loading. As previously reported, PET studies 6,8,14,27 did not evaluate the combination of cerebral hemodynamics and metabolism and factors affecting the hemodynamic status of patients with AVM.…”

“…Previous reports showed decreased rCBF in areas surrounding the AVM, 2,4,6,8,10,11,14,15,17,19,[23][24][25][26]28 especially larger AVMs. 2,10,15,28 Our detailed analysis revealed that patients with angiographically defined high-flow AVMs manifested the greatest decrease in rCBF in the ROI-p (high-flow AVMs compared with nonhigh-flow, p = 0.022) and that the flow type exerted a greater effect on rCBF than the size of the AVM.…”

Arteriovenous Brain Malformations: Is Functional MR Imaging Reliable for Studying Language Reorganization in Patients? Initial Observations

“…The working model of BOLD contrast MR imaging postulates that an increase in neuronal activity causes blood flow to increase such that the amount of paramagnetic deoxyhemoglobin in the microvasculature is reduced, and this leads to an increase in T2* relaxation and thus in signal intensity (16). Changes in cerebral blood flow (27,32,33), perfusion pressure (28 -30,33), oxygen metabolism (34), autoregulation process, and vasoreactivity (27)(28)(29)33,(35)(36)(37), all of which have been reported in areas adjacent to AVMs, may alter BOLD signal intensity detection. The combined use of BOLD contrast and other perfusion techniques, such as arterial spin labeling, might yield different sensitivity in cases of flow abnormalities and thus help in determining language lateralization (38).…”

Postoperative Hyperperfusion Associated With Steal Phenomenon Caused by a Small Arteriovenous Malformation-Case Report-

“…4,12) Arterial blood is shunted through the low-resistance arteriovenous fistula of the AVM away from the normal brain tissue adjacent to and distant from the AVM, widely known as the steal phenomenon. 4,7,14) AVMs are generally associated with large nidus, massive blood shunting, impaired autoregulation, venous congestion, and hypoperfusion in the surrounding tissues, which are all potential causes of postoperative hyperperfusion, resulting in complications such as cerebral edema and intracerebral hemorrhage. 1,2,12) Hemodynamic changes associated with an AVM with a relatively small nidus, which may cause disastrous postoperative complications, are not well understood.…”