Hemodynamic stress distribution reflects ischemic clinical symptoms of patients with moyamoya disease.

OBJECTIVE

Currently, the probability of diagnosing asymptomatic moyamoya disease is increasing. In this study, we consider a less invasive method for predicting future ischemic symptoms in patients with moyamoya disease.

METHODS

We reviewed cerebral blood flow (CBF)-related data obtained by xenon CT imaging (XeCT) in six patients with ischemic-type or asymptomatic moyamoya disease. The data were obtained as volume data using a 320-row CT, and applied to the automated region-of-interest-determining software (3DSRT) and converted to standardized images. Eight CBF-related parameters, including CBF value, cerebrovascular reserve capacity (CVRC), and hemodynamic distribution (hdSD), were compared between asymptomatic hemispheres and ischemic symptomatic hemispheres. A significant difference was determined by a two-sample t test. A difference with p<0.05 was considered significant. When statistically significant differences between parameters of asymptomatic hemispheres and ischemic symptomatic hemispheres were identified, cut-off points were calculated with receiver operating characteristic (ROC) curves. Change in the parameters before and after bypass surgery was also assessed.

RESULTS

Of the eight CBF-related parameters evaluated, statistically significant differences between the asymptomatic hemispheres and ischemic hemispheres were observed in the CBF value of the MCA region (CBF-MCA), both at rest and after acetazolamide loading, and in the hdSD, also both at rest and after acetazolamide loading. Of the four statistically significant parameters, ROC analysis revealed that the hdSD at rest and CBF-MCA after acetazolamide loading were the most sensitive and specific parameters (threshold 1.2, sensitivity 1, specificity 1 for hdSD at rest, and threshold 26.44mL/100g/min, sensitivity 1, specificity 1 for CBF-MCA after acetazolamide loading). From the CBF data obtained both before and after surgery from the three patients who had undergone direct bypass surgeries, the hdSD was higher than the threshold of 1.2 before surgery but decreased to lower than the threshold of 1.2 after surgery. Ischemic symptoms also resolved after surgery.

CONCLUSIONS

The data showed that hdSD at rest and CBF-MCA after acetazolamide loading reflects ischemic symptoms of patients with moyamoya disease. Thus, these parameters could be used as ischemic symptom markers for following patients with moyamoya disease. hdSD at rest is important because it is less invasive and can be performed without acetazolamide loading.