Topographic changes in cerebral blood flow and reduced white matter integrity in the first 2 weeks following revascularization surgery in adult moyamoya disease

Abstract

OBJECTIVE After revascularization surgery, hyperperfusion and ischemia are associated with morbidity and mortality in adult moyamoya disease (MMD). However, structural changes within the brain following revascularization surgery, especially in the early postsurgical period, have not been thoroughly studied. Such knowledge may enable improved monitoring and clinical management of hyperperfusion and ischemia in MMD. Thus, the objective of this study was to investigate the topographic and temporal profiles of cerebral perfusion and related white matter microstructural changes following revascularization surgery in adult MMD. METHODS The authors analyzed 20 consecutive surgeries performed in 17 adults. Diffusion imaging in parallel with serial measurements of regional cerebral blood flow (rCBF) using SPECT was performed. Both voxel-based and region-of-interest analyses were performed, comparing neuroimaging parameters of postoperative hemispheres with those of preoperative hemispheres at 4 different time points within 2 weeks after surgery. RESULTS Voxel-based analysis showed a distinct topographic pattern of cerebral perfusion, characterized by increased rCBF in the basal ganglia for the first several days and gradually increased rCBF in the lateral prefrontal cortex over 1 week (p < 0.001). Decreased rCBF was also observed in the lateral prefrontal cortex, occipital lobe, and cerebellum contralateral to the surgical hemisphere (p < 0.001). Reduced fractional anisotropy (FA) and axial diffusivity (AD), as well as increased radial diffusivity (RD), were demonstrated in both the anterior and posterior limbs of the internal capsule (p < 0.001). Diffusion parameters demonstrated the greatest changes in both FA and RD on Days 1-2 and in AD on Days 3-6; FA, RD, and AD recovered to preoperative levels on Day 14. Patients with transient neurological deteriorations (TNDs), as compared with those without, demonstrated greater increases in rCBF in both the lateral prefrontal cortex and striatum as well as smaller FAs in the posterior limb of the internal capsule (p < 0.05). CONCLUSIONS The excessively increased rCBF and the recovery process were heterogeneous across brain regions, demonstrating a distinct topographic pattern during the initial 2 weeks following revascularization surgery in MMD. Temporary impairments in the deep white matter tract and immediate postoperative ischemia were also identified. The study results characterized postoperative brain perfusion as well as the impact of revascularization surgery on the brain microstructure. Notably, rCBF and white matter changes correlated to TNDs, suggesting that these changes represent potential neuroimaging markers for tracking tissue structural changes associated with hyperperfusion during the acute postoperative period following revascularization surgery for MMD.

Postoperative Intracerebral Hemorrhage After Combined Revascularization Surgery in Moyamoya Disease: Profiles and Clinical Associations

“…Moreover, the area of increased regional CBF shifted to the lateral prefrontal cortex approximately one week after the surgery. 25 This phenomenon matches with the ICH pattern in this study because of the onset timing and hematoma location at an earlier phase, such as POD 0-2; and the typical TNDs due to CHP occurring around POD 7-8. Importantly, the present study shows that some of the cases developed ICH before the standard postoperative CBF assessment or exhibited ICH despite reduced increase in CBF after surgery.…”

“…3,23,24 The discrepancy between typical CHP and ICH, as observed in this study, with respect to onset timing and location, can be explained by the findings of a past study that reported a topographic change in regional CBF in the first 2 weeks after surgery. 25 This report demonstrated that direct Tokairin 11 revascularization provides additional CBF to the basal ganglia and subcortical lesions in the frontotemporal lobes immediately after surgery. Moreover, the area of increased regional CBF shifted to the lateral prefrontal cortex approximately one week after the surgery.…”

Mapping altered brain connectivity and its clinical associations in adult moyamoya disease: A resting-state functional MRI study

“…In particular, it has not been determined whether the temporal correlations of low-frequency BOLD signals are altered in patients with an otherwise apparently healthy brain, who are potential candidates requiring early detection of cognitive impairments. Previous investigations using voxel-based analysis have demonstrated altered distribution of regional cerebral blood flow (rCBF) in MMD, before and after the revascularization surgery [ 21 , 22 ]. However, the extent of alterations in low-frequency BOLD signals associated with vascular lesions and rCBF has not been clearly demonstrated.…”

Combined structural and diffusion tensor imaging detection of ischemic injury in moyamoya disease: relation to disease advancement and cerebral hypoperfusion

“…Furthermore, measurements of the brain microstructure can be used to evaluate the effects of therapeutic interventions such as revascularization surgery. [7][8][9] Diffusion imaging, postacquisition image processing techniques, and quantification of diffusion parameters allow one to determine the profile of white matter injuries such as reduced fiber density, demyelination, and axonal injury. 10 In moyamoya disease, DTI parameters such as fractional anisotropy (FA), radial diffusivity, and mean diffusivity are altered.…”