Postoperative hyperperfusion in a patient with a dural arteriovenous fistula with retrograde leptomeningeal venous drainage: case report

Prolonged Hemiplegic Migraine Led to Persistent Hyperperfusion and Cortical Necrosis: Case Report and Literature Review

Hemiplegic migraine (HM) is a rare subtype of migraine characterized by aura of motor weakness accompanied by visual, sensory, and/or speech symptoms. Aura symptoms usually resolve completely; permanent attack-related deficit and radiographic change were rare. Here, we reported a case presented with progressively aggravated hemiplegic migraine episodes refractory to medication. He experienced two prolonged hemiplegic migraine attacks that led to irreversible visual impairment and cortical necrosis on brain MRI. Multimodal MRI during attack showed persistent vasodilation and hyperperfusion in the affected hemisphere associated with deterioration of clinical symptoms and worsening of brain edema. Patent foramen ovale (PFO) was found on the patient. PFO closure resulted in a significant reduction of HM attacks. This case indicated that prolonged hemiplegic migraine attack could result in irreversible neurological deficit with radiographic changes manifested as cortical necrosis. Persistent hyperperfusion might be an important factor contributing to prolonged attack and persistent attack-related neurological deficit. We recommend screening for PFO in patients with prolonged or intractable hemiplegic migraine, for that closure of PFO might alleviate the attacks thus preventing the patient from disabling sequelae.

A study on blood–brain barrier ultrastructural changes induced by cerebral hypoperfusion of different stages

OBJECTIVES

To evaluate the ultrastructural changes in the blood-brain barrier (BBB) induced by cerebral hypoperfusion of different stages, which may predispose the brain to the formation of vasogenic edema and hemorrhage under cerebral luxury perfusion.

METHODS

Twenty cerebral steal models with left neck arteriovenous fistula (AVF) were surgically created in Wistar's rats, leading to a noninfarctional reduction in the cerebral blood flow (CBF) by between 25 and 50%, resulting in cerebral hypoperfusion in the AVF side for 3 days (acute stage), 3 weeks (subacute stage) and 3 months (chronic stage), respectively. Another six sham-operated models were made in age-matched rats as control. The BBB ultrastructural changes were assessed by transmission electron microscopy. Ridit analysis was conducted to compare the positive ratio of ultrastructural changes among multiple groups.

RESULTS

Electron microscopy demonstrated no ultrastructural change at the acute stage, however, at the subacute stage, slight vacuolar degeneration was found in the astrocytic foot process layer encircling the capillaries; furthermore, at the chronic stage, the astrocytic foot processes expressed marked vacuolization associated with the adjacent astrocytic degeneration. Meanwhile, in both capillary endothelium and basal lamina layers, no abnormal ultrastructures similar to those in the astrocytic foot processes layer were identified. After cerebral luxury perfusion took place, BBB was disrupted where astrocytic foot processes vacuolization was most distinguished.

CONCLUSION

Astrocytes generate ultrastructural abnormality as a result of chronic cerebral hypoperfusion. Astrocytic foot process vacuolization, which constitutes the major ultrastructural change in the BBB, is the extension of the degeneration of astrocyte body. It is inferred that BBB is prone to structure weakness and function instability, which forms the morphological basis of cerebral luxury perfusion.

Hemodynamic studies of intracranial dural arteriovenous fistulas using arterial spin-labeling MR imaging

Arterial spin-labeling (ASL) magnetic resonance imaging (MRI) enables non-invasive acquisition of the brain perfusion information in cerebrovascular disease. We investigated hemodynamic changes in intracranial dural arteriovenous fistulas (DAVFs) using ASL-MRI. ASL-MRI by a Q2TIPS sequence on a 3.0-Tesla MRI was performed for three patients with Cognard's IIa+b type of DAVFs before and after treatment. Perfusion images obtained by ASL-MRI (ASL images) before treatment were visually compared with those by single-photon emission computed tomography images (SPECT images). Increasing rates of temporal changes of regional perfusion values in ASL images (ASL values) before and after treatment were also calculated. In all three patients, ASL images before treatment demonstrated high perfusion in regions around the shunting areas, where normal or low perfusion were detected on SPECT images; thus, ASL images might have demonstrated the abundant arterial shunting flow via the fistulas. On days eight to 20 after treatment, ASL values around the shunt areas remained the same or decreased, and those in the regions other than the shunt areas increased in all three patients. This might have been due to a combination of the following: a decrease in shunt flow volume, an amelioration of venous congestion, and a sustained an upward shift in the autoregulation of the brain perfusion pressure. All regional ASL values decreased on days 112 and 120 after treatment in two patients, which possibly reflects a reduction in the upward shift in autoregulation. ASL-MRI might be useful for identifying the hemodynamic behavior of DAVFs before and after treatment.

Reversibility of cognitive disorder after treatment of dural arteriovenous fistulae

INTRODUCTION

Dural arteriovenous fistulae (DAVF) occasionally lead to cognitive disorders whose reversibility after DAVF treatment remains unclear. We studied changes on pre- and post-treatment magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) scans in ten patients with cognitive disorder due to DAVF.

METHODS

We studied the symptoms, pre- and post-treatment MRI scans, SPECT findings, and mini-mental state examination (MMSE) and treatment results in ten patients with cognitive disorder due to DAVF. They were divided into two groups; the post-treatment MMSE score exceeded 25 points in group 1 (n = 6) and was lower than 24 points in group 2 (n = 4).

RESULTS

In the six group 1 patients, pretreatment diffusion-weighted images (DWI) showed hyperintense areas, and SPECT scans demonstrated the preservation of vasoreactivity after acetazolamide challenge. In the four group 2 patients, pretreatment SPECT demonstrated hypoperfusion areas that coincided with the hyperintense areas seen on DWI; there were areas with marked disturbance in vasoreactivity. The post-treatment MMSE score in groups 1 and 2 improved by 13.7 +/- 2.4 and 3.8 +/- 1.0 points, respectively; the difference was significant at p < 0.01.

CONCLUSION

In patients with cognitive disorder due to DAVF, the preservation of vasoreactivity on SPECT after acetazolamide challenge indicates that their cognitive disorder may be reversible by DAVF treatment.