Intramural Hematoma Detection by Susceptibility-Weighted Imaging in Intracranial Vertebral Artery Dissection

Abstract

Background: The radiologic diagnosis of vertebral artery dissection (VAD) depends on characteristic intraluminal findings on angiography and intramural hematoma or a double-lumen sign on high-resolution vessel wall imaging. We aimed to evaluate the accuracy of intramural hematoma sign on susceptibility-weighted imaging (SWI) in VAD. Methods: We retrospectively analyzed SWI, phase map images and brain computed tomography (CT) of the consecutive patients who suffered an ischemic stroke in the vertebral artery territory from August 2010 to July 2012. We divided the patients into 2 groups: the VAD group and the nondissection group. VAD was diagnosed by conventional catheter angiographic findings (aneurysmal dilatation, pearl-and-string or tapered steno-occlusion) and pathognomonic findings such as intramural hematoma or a double-lumen sign on the source images of TOF-MRA, high-resolution T₁-weighted MRI or high-resolution T₂-weighted MRI. Intramural hematoma sign was considered positive if the patient had an eccentric or concentric hypointense signal lesion in the vertebral artery on SWI, a corresponding hyperintense signal on phase map and no evidence of calcification on the brain CT, suggesting blood products other than calcification. Two experienced neuroradiologists blinded to clinical information and angiographic findings were asked to judge for the presence of intramural hematoma sign on SWI. The accuracy of intramural hematoma sign on SWI was evaluated. Phase value, demographic and clinical data were compared between the VAD and the nondissection groups. Results: Thirty-nine patients were included: 10 in the VAD group and 29 in the non-dissection group. Among the VAD group cases, intramural hematoma sign on SWI was positive in 9 of the 10 VAD cases and in 1 out of the 29 cases in the nondissection group. The intramural hematoma sign on SWI was significantly associated with VAD (p < 0.001), and showed sensitivity of 90% and specificity of 96.6%. Mean phase values of intramural hematomas (n = 9) were all positive and those of calcified lesions (n = 13) were all negative (0.45 radian vs. -0.42 radian, p < 0.001). Conclusions: The intramural hematoma sign on SWI was significantly associated with VAD and the phase map values were higher in intramural hematomas when compared with atherosclerotic calcifications.

Multi-Contrast High-Resolution Magnetic Resonance Findings of Spontaneous and Unruptured Intracranial Vertebral Artery Dissection: Qualitative and Quantitative Analysis According to Stages

“…Although the usefulness of HR-MRI in assessing a subarachnoid hemorrhage may be questioned, further studies will be necessary. Finally, advanced imaging sequences, such as susceptibility weighted imaging, were not investigated in our analyses but may also provide useful information [1] regarding the determination of dissection age in a future report. Therefore, prospective studies with intraindividual design and advanced imaging methods are still necessary.…”

“…Spontaneous intracranial vertebral artery dissection (IVAD) is one of the most important causes of stroke in young and middle-aged adults [1] , which has been detected more frequently with advancements in neurovascular imaging [2,3] . IVAD is the most common (67.1-78.0%), spontaneous, intracranial artery dissection found in Asian populations [4,5] .…”

Intracranial Vessel Wall MRI: Principles and Expert Consensus Recommendations of the American Society of Neuroradiology

“…The deoxygenation of blood that makes it conspicuous on these sequences occurs earlier than the conversion from deoxyhemoglobin to methemoglobin required for intramural hematoma to become hyperintense on a T1-weighted sequence. 47 The evolution of blood products is also complicated by the dynamic nature of dissection itself, which can be stable, progressive, or resolving. Intracranial arterial dissection with VW-MR imaging evidence of intramural hematoma is more likely to progress than dissection without hematoma.…”

Giant Intracranial Aneurysms at 7T MRI

“…In view of the previously published data, spatial resolution has to be well below aneurysm wall thickness to be capable of demonstrating microstructures within the wall. The spatial resolution used in our study was 5.7-13.2 times higher compared with previous in vivo aneurysm wall studies, 10,11,[13][14][15] which was sufficient to visualize the microstructures in vivo for the first time.…”

“…In previously published in vivo aneurysm wall imaging studies, depiction of microstructures within aneurysm walls was limited by spatial resolution, [13][14][15] because wall thicknesses ranged from 20 to 500 m. 16,17 To date, there is only 1 report on intracranial vessel wall microstructures delineated with 7T MR imaging using an ultra-high ex vivo 0.11 ϫ 0.11 mm 2 resolution. 18 The study showed excellent correlation with the histopathologic findings.…”