MRA question

My husband has family history ( 3 first degree relatives- father and 2 brothers) who had aneurysmal Subarachnoid hemorrhage. Both brothers  had their SAH in their late 40s, father in his mid 50's. All three were alcoholic, heavy smoking, and medically non-compliant for HTN, hypercholesterol, and diabetes. Both brothers succumbed to their SAH, father survived ( impaired) x 10 years.

Husband had screening MRA, which was noted  " unremarkable" but included comment regarding "tortuous but patent basilar artery".  Is this a normal variant?   thanks