| Background and aimsVertebrobasilar artery dissecting aneurysm (VBA-DA) characterized by intramural hematoma and dissection flap is one of the cerebrovascular diseases caused by large amounts of etiologies, which initial symptoms showed subarachnoid hemorrhage (SAH) or ischemia of brain stem. The curative effect of VBA-DA had been improved satisfactorily by interventional therapy. Nevertheless, VBA-DA remain a hard nut to crack because of its serious complication and poor prognosis. Although digital subtraction angiography (DSA) remains the criterion standard of imaging techniques for cerebrovascular diseases, high-resolution magnetic resonance imaging (HR-MRI) should be the first-line method for VBA-DA diagnosis. HR-MRI can not only display the vessel lumen but also reflect the lesion of vessel wall, which is superior to DSA or other traditional clinical examination. HR-MRI can be used to diagnose VBA-DA noninvasively and may help to provide guidance to treatment.MethodsFrom November 2013 to October 2015, the DSA, HR-MRI and clinical follow-up of 44 consecutive patients with VBA-DA receiving treatment were prospectively collected in neurosurgery department of Qilu Hospital affiliated Shandong University. According to inclusive criteria and exclusion criteria,39 cases were selected eventually. The patients received HR-MRI, including three dimensional time of flight magnetic resonance angiography (3D-T0F-MRA), three-dimensional fast imaging employing steady state acquisition (3D-FIESTA) and three-dimensional Tl weighted imaging (3D-T1WI). Clinical follow-up was carried out from 3 months to 25 months. Comparisons were made with analysis of variance (ANOVAs) and Fisher’s exact test.Result39 consecutive patients were selected into this clinical research. The incidence of VBA-DA on vertebral artery was higher than basilar artery (71.4% vs.19.1%, χ2=11.56, P<0.01). Considering the relationship between posterior inferior cerebellar artery (PICA), results showed that the incidence rate of dissection distal to PICA was superior to proximal (66.7% vs.11.9%, x2=32.36, p<0.01). No apparent distribution difference between dissection located at ventrolateral region and at dorsolateral region was discovered in this research (45.2% vs.54.8%,χ2=0.076, P>0.05). The incidence of left vertebral artery dominance was obviously higher than that of right (81.0%vs. 19.0%,χ2=16.10, P<0.01). Among the vessels with dissecting aneurysm, the incidence of VBA-DA on dominant vertebral artery was obviously higher than that on non-dominant vertebral artery (95.2% vs.4.8%, χ2=34.38, P<0.01).3D-TOF-MRA and 3D-FIESTA exhibited important diagnostic significance on intramural hematoma and dissection flap. The presentation on HR-MRI were classified into 4-type, named as classical type dissection, stenosis type dissection, spiral type dissection and hemorrhagic type dissection, respectively. Obvious significant difference was observed among the four types of VBA-DA in improvement rate and exacerbation rate (P=0.015). The prognosis of classical type dissection was better than that of spiral type dissection and hemorrhagic type (P<0.05).ConclusionThis study shows that HR-MRI can be a useful and non-invasive tool for evaluating the structure and prognosis of VBA-DA. According to this research, we present a new classification of VBA-DA and formulate individual operation plans. Prognosis of classical type dissection would be optimistic, but pessimistic for spiral type dissection and hemorrhagic type dissection.SignificanceThis study combined HR-MRI with DSA in researching a set of consecutive patients suffering from VBA-DA. What’s more, this research put forward a new classification of VBA-DA from the clinical point and carried out statistic analysis on the relationship between each type and clinical prognosis. Therefore, individualized treatment could be made to direct clinical therapy on the classification. |
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