Enhancement of robin-virchow spaces MRI evaluation

Quantification of perivascular spaces at 7T: A potential MRI biomarker for epilepsy

PURPOSE

7T (7T) magnetic resonance imaging (MRI) facilitates the visualization of the brain with resolution and contrast beyond what is available at conventional clinical field strengths, enabling improved detection and quantification of small structural features such as perivascular spaces (PVSs). The distribution of PVSs, detected in vivo at 7T, may act as a biomarker for the effects of epilepsy. In this work, we systematically quantify the PVSs in the brains of epilepsy patients and compare them to healthy controls.

METHODS

T₂-weighted turbo spin echo images were obtained at 7T on 21 epilepsy patients and 17 healthy controls. For all subjects, PVSs were manually marked on Osirix image analysis software. Marked PVSs with diameter≥0.5mm were then mapped by hemisphere and lobe. The asymmetry index (AI) was calculated for each region and the maximum asymmetry index (|AI_max|) was reported for each subject. The asymmetry in epilepsy subjects was compared to that of controls, and the region with highest asymmetry was compared to the suspected seizure onset zone.

RESULTS

There was a significant difference between the |AI_max| in epilepsy subjects and in controls (p=0.016). In 72% of patients, the region or lobe of the brain showing maximum PVS asymmetry was the same as the region containing the suspected seizure onset zone.

CONCLUSION

These findings suggest that epilepsy may be associated with significantly asymmetric distribution of PVSs in the brain. Furthermore, the region of maximal asymmetry of the PVSs may help provide localization or confirmation of the seizure onset zone.

Regression of dilated perivascular spaces of the brain

PURPOSE

Perivascular, or Virchow-Robin, spaces of the brain represent interstitial fluid-filled spaces continuous with subpial spaces, and not invagination of cerebrospinal fluid-filled subarachnoid spaces. Regression of a dilated, or even giant, perivascular space occurs rarely. The purpose of this paper is to describe magnetic resonance imaging evidence of complete regression of dilated perivascular spaces (dPVSs).

METHODS

Patient 1 was a 76-year-old woman with right hemiparesis and aphasia from a left cranial vault meningioma infiltrating the superior sagittal sinus, and a left temporal lobe giant perivascular space. Patient 2 was a 70-year-old man with pituitary apoplexy, vasospasm, cerebral ischemia, and two dPVSs, one in the right temporal lobe, and one in the left anterior perforate substance. Patient 3 was a 78-year-old man with a generalized seizure, and a right temporal lobe dPVS.

RESULTS

In all the patients, temporal lobe giant or dPVSs underwent regression, following meningioma subtotal resection (patient 1) or pituitary lesion shrinkage (patient 2), or spontaneously (patient 3). In patient 2, the left anterior perforate substance dPVS was unchanged.

CONCLUSIONS

Temporal lobe giant or dPVSs may regress, eventually together with resection or regression of intracranial tumors, also distant from the PVSs. Cerebral edema does not seem the only factor influencing dilatation of PVSs.