Hemodynamic and metabolic changes in crossed cerebellar hypoperfusion.

Abstract

Background and Purpose:The pathophysiology of crossed cerebellar diaschisis remains to be elucidated. The mechanism responsible appears to be deafferentation through the corticopontocerebellar tract, which terminates in the cerebellar gray matter. However, few studies have demonstrated the hemodynamic and metabolic changes in the cerebellar gray matter and pons in crossed cerebellar diaschisis.Methods: Using positron emission tomography in 24 patients with unilateral supratentorial stroke, we evaluated regional blood flow, metabolic rate of oxygen, oxygen extraction fraction, and blood volume in the cerebellar cortex and pons. Sixteen patients with significant cerebellar blood flow asymmetry, defined as a percentage difference in blood flow beyond the upper 95% confidence limit defined in eight normal subjects, were selected as the group with crossed cerebellar hypoperfusion.Results: In patients with crossed cerebellar hypoperfusion, the metabolic rate of oxygen was significantly decreased in the cerebellar cortex contralateral to the supratentorial stroke, compared with that in the ipsilateral cerebellar cortex; this decrease was less than the decrease in cerebellar blood flow. The degrees of cerebellar asymmetry in these two parameters were negatively correlated with the metabolic rate of oxygen in the pons. The oxygen extraction fraction was slightly, but significantly, increased. In contrast to the ischemic state, however, the cerebellar blood volume was decreased, with no difference in the ratio of cerebellar blood flow to blood volume.Conclusions: These findings support interruption of the corticopontocerebellar tract as the mechanism of crossed cerebellar hypoperfusion. Our results also suggest a mild elevation in the oxygen extraction fraction in this state, with a mechanism distinct from ischemia. (Stroke 1992;23:855-860)

Changes in Human Cerebral Blood Flow and Cerebral Blood Volume during Hypercapnia and Hypocapnia Measured by Positron Emission Tomography

“…Scale maximum and minimum values are 70 and 0 mL·100 mL −1 min −1 for CBF, and 8 and 0 mL/100 mL for CBV, respectively. (Yamauchi et al, 1992;Ito et al, 2002). However, the degree of decrease in CBF during hypocapnia was greater than that in CBV (approximately 40% decrease in CBF and 10% decrease in CBV), indicating a decrease in vascular blood velocity during hypocapnia.…”

Crossed cerebellar diaschisis after stroke: Can perfusion-weighted MRI show functional inactivation?

“…With 85%, the occurrence of significant CCD after stroke in our study is quite high, but still in line with the literature. For example, PET-based studies reported incidence of CCD in 67% (Yamauchi et al, 1992) and 89% of patients (Miura et al, 1994). Two previous studies dealt with MRI-based detection of CCD: Yamada et al (1999) found an incidence of 80%, whereas Lin et al (2009) reported CCD in only 16% of patients.…”

Behind the scenes of functional brain imaging: A historical and physiological perspective

“…Complementing these observations from functional brain imaging on the relationship between oxygen consumption and blood flow during decreases are earlier quantitative metabolic studies of a phenomenon known as cerebellar diaschisis (53,54). In this condition, there is a reduction in blood flow and metabolism in the hemisphere of the cerebellum contralateral to an injury to the cerebral cortex, usually a stroke.…”

“…In this condition, there is a reduction in blood flow and metabolism in the hemisphere of the cerebellum contralateral to an injury to the cerebral cortex, usually a stroke. Of particular interest is the fact that blood flow is reduced significantly more than oxygen consumption (53,54). The changes in the cerebellum are thought to reflect a reduction in neuronal activity within the cerebellum due to reduced input from the cerebral cortex.…”