Objectives: The purpose of this study was to evaluate the associations between vertebral artery hypoplasia (VAH) and the morphologic types of spontaneous vertebral artery dissection (sVAD) and to assess the chronological changes of VAH after sVAD.
Methods and materials: In this retrospective study, we included 208 patients with 216 sVADs which were diagnosed between January 2003 and June 2017 at two tertiary hospitals. Morphologic types of sVAD were classified into aneurysmal dilatation without stenosis, pearl-and-string appearance, and steno-occlusion without aneurysmal dilatation. Baseline clinical characteristics and sVAD types were compared according to the presence of VAH on initial imaging. For 143 sVAD patients with follow-up imaging available, chronological changes of VAH and their associations with sVAD types were also evaluated.
Result: VAH was detected in 29 (13.9%) subjects: 18 (8.7%) with ipsilateral VAH and 11 (5.3%) with contralateral VAH to the sVAD site. Primary lesion shape was statistically associated with the presence of VAH (P = 0.001); steno-occlusion without dilatation was more frequently observed in the ipsilateral VAH group (44.4%) than the no-VAH group (20.9%) or contralateral VAH group (0%). Of a total 143 sVAD patients with follow-up imaging available, VAH-like diffuse VA narrowing was newly observed in seven patients and four patients who were initially classified into the VAH group showed their VAH-like appearances resolved.
Conclusions: The presence of VAH may be associated with the morphologic subtype of sVAD and the VA diameter can dynamically change, making it possible for the VAH-like appearance to be induced after a sVAD event.
Keywords: Diagnostic imaging; Vertebral artery; Vertebral artery dissection.
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