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Vessel Wall MR Imaging - AJNR News Digest - September 2019
September-October 2019
Introduction
Gadolinium-Enhancement-of-Aneurysm-Wall

Vessel Wall MR Imaging

Maria Vittoria Spampinato

High-resolution intracranial vessel wall MR imaging (VW-MRI) has emerged in recent years as the leading imaging modality for the visualization and characterization of the arterial vessel wall.1-3 VW-MRI has a complementary role to luminal imaging techniques, and has been increasingly used as a clinical tool in the diagnosis of intracranial vascular diseases at many centers worldwide.4-16 In this installment of the AJNR News Digest, we highlight some of the recent AJNR publications on VW-MRI.

What Are the Challenges of Vessel Wall MR Imaging?

The implementation of VW-MRI is technically challenging and dependent on the specific scanner and software available at an imaging facility. Requirements of VW-MRI are high spatial resolution, multiplanar 2D or preferably 3D acquisitions, multiple tissue weightings, and suppression of intraluminal blood and CSF signal.2 The American Society of Neuroradiology Vessel Wall Imaging Study Group is leading the way in the development of vendor- and scanner-specific protocols.2 The recent work by Lindenholz et al exemplifies the standardization efforts required for VW-MRI protocol optimization.17 Due to the high spatial resolution required to image the vessel wall, scan duration can be long to achieve an adequate signal-to-noise ratio. Lindenholz et al have tested the use of different T1-weighted sequence variants with different contrast, spatial resolution, signal-to-noise ratio, and scan duration, and developed a 30% faster sequence that results in very good visibility of the intracranial vessel wall.

Intracranial Aneurysm

Research efforts are underway to investigate the role of VW-MRI in the characterization and risk stratification of intracranial aneurysms.8 In a recent study by Kim et al, VW-MRI provided better image quality and accuracy compared with time-of-flight MR angiography in the assessment of stented parent arteries after aneurysm embolization.18 In a longitudinal study, Vergouwen et al found that none of the 46 nonenhancing aneurysms changed in size or ruptured during the follow-up, while 4 out of 19 enhancing aneurysms grew or ruptured.19

Larsen et al found an association between aneurysm wall enhancement and signs of inflammation and potential instability on histology after surgical clipping of unruptured aneurysms.20 Sato et al examined different patterns of aneurysmal wall enhancement using a high-resolution technique at 7T and compared imaging findings with histology.21 At high resolution, “double-rim” enhancement of both the outer and inner walls of the aneurysm correlated with histologic findings of aneurysm instability. These studies highlight the role of aneurysm wall enhancement as a novel biomarker of aneurysm instability.

Vasculitis and Atherosclerotic Disease

Intracranial blood vessel biopsy has a role in the differentiation of CNS vasculitis from noninflammatory vasculopathy (eg, atherosclerotic disease) and in the differential diagnosis of inflammatory conditions of the intracranial vasculature. Zeiler et al used VW-MRI to identify suitable biopsy targets in patients with suspected CNS vasculitis and found vascular inflammatory changes in 8 of the 9 surgical specimens analyzed.22 

This work indicates that VW-MRI can improve the yield of biopsy in patients with CNS vasculitis, while histology remains vital in determining the etiology of the inflammation. Finally, current practice guidelines for intracranial atherosclerotic disease (ICAD) rely primarily on the degree of arterial stenosis (ie, ≥50%) to determine management. The study by Zhu et al illustrates how, in the future, VW-MRI may have a role in the risk stratification and management of ICAD.23 Intraplaque hemorrhage, detected in atherosclerotic lesions of the basilar artery on VW-MRI, was independently associated with stroke symptoms regardless of the degree of stenosis.

References

  1. Lehman VT, Brinjikji W, Kallmes DF, et al. Clinical interpretation of high-resolution vessel wall MRI of intracranial arterial diseases. Br J Radiol 2016;89:20160496, 10.1259/bjr.20160496.
  2. Mandell DM, Mossa-Basha M, Qiao Y, et al. Intracranial vessel wall MRI: principles and expert consensus recommendations of the American Society of Neuroradiology. AJNR Am J Neuroradiol 2017;38:218–29, 10.3174/ajnr.A4893.
  3. Swartz RH, Bhuta SS, Farb RI, et al. Intracranial arterial wall imaging using high-resolution 3-tesla contrast-enhanced MRI. Neurology 2009;72:627–34, 10.1212/01.wnl.0000342470.69739.b3.
  4. Ryu CW, Jahng GH, Kim EJ, et al. High resolution wall and lumen MRI of the middle cerebral arteries at 3 tesla. Cerebrovasc Dis 2009;27:433–42, 10.1159/000209238.
  5. Zhu XJ, Du B, Lou X, et al. Morphologic characteristics of atherosclerotic middle cerebral arteries on 3T high-resolution MRI. AJNR Am J Neuroradiol 2013;34:1717–22, 10.3174/ajnr.A3573.
  6. Mossa-Basha M, Hwang WD, De Havenon A, et al. Multicontrast high-resolution vessel wall magnetic resonance imaging and its value in differentiating intracranial vasculopathic processes. Stroke 2015;46:1567–73, 10.1161/STROKEAHA.115.009037.
  7. Mandell DM, Matouk CC, Farb RI, et al. Vessel wall MRI to differentiate between reversible cerebral vasoconstriction syndrome and central nervous system vasculitis: preliminary results. Stroke 2012;43:860–62, 10.1161/STROKEAHA.111.626184.
  8. Texakalidis P, Hilditch CA, Lehman V, et al. Vessel wall imaging of intracranial aneurysms: systematic review and meta-analysis. World Neurosurg 2018;117:453–58, e451, 10.1016/j.wneu.2018.06.008.
  9. Turan TN, Bonilha L, Morgan PS, et al. Intraplaque hemorrhage in symptomatic intracranial atherosclerotic disease. J Neuroimaging 2011;21:e159–61, 10.1111/j.1552-6569.2009.00442.x
  10. Turan TN, Rumboldt Z, Granholm AC, et al. Intracranial atherosclerosis: correlation between in-vivo 3T high resolution MRI and pathology. Atherosclerosis 2014;237:460–63, 10.1016/j.atherosclerosis.2014.10.007.
  11. Al-Smadi AS, Abdalla RN, Elmokadem AH, et al. Diagnostic accuracy of high-resolution black-blood MRI in the evaluation of intracranial large-vessel arterial occlusions. AJNR Am J Neuroradiol 2019;40:954–59, 10.3174/ajnr.A6065.
  12. Bai X, Lv P, Liu K, et al. 3D black-blood luminal angiography derived from high-resolution MR vessel wall imaging in detecting MCA stenosis: a preliminary study. AJNR Am J Neuroradiol 2018;39:1827–32, 10.3174/ajnr.A5770.
  13. Dlamini N, Yau I, Muthusami P, et al. Arterial wall imaging in pediatric stroke. Stroke 2018;49:891–98, 10.1161/STROKEAHA.117.019827.
  14. Qiao Y, Zeiler SR, Mirbagheri S, et al. Intracranial plaque enhancement in patients with cerebrovascular events on high-spatial-resolution MR images. Radiology 2014;271:534–42, 10.1148/radiol.13122812.
  15. Skarpathiotakis M, Mandell DM, Swartz RH, et al. Intracranial atherosclerotic plaque enhancement in patients with ischemic stroke. AJNR Am J Neuroradiol 2013;34:299–304, 10.3174/ajnr.A3209.
  16. Qiao Y, Anwar Z, Intrapiromkul J, et al. Patterns and implications of intracranial arterial remodeling in stroke patients. Stroke 2016;47:434–40, 10.1161/STROKEAHA.115.009955.
  17. Lindenholz A, Harteveld AA, Zwanenburg JJ, et al. Comparison of 3T intracranial vessel wall MRI sequences. AJNR Am J Neuroradiol 2018;39:1112–20, 10.3174/ajnr.A5629.
  18. Kim S, Kang M, Kim DW, et al. Usefulness of vessel wall MR imaging for follow-up after stent-assisted coil embolization of intracranial aneurysms. AJNR Am J Neuroradiol 2018;39:2088–94, 10.3174/ajnr.A5824.
  19. Vergouwen MDI, Backes D, van der Schaaf IC, et al. Gadolinium enhancement of the aneurysm wall in unruptured intracranial aneurysms is associated with an increased risk of aneurysm instability: a follow-up study. AJNR Am J Neuroradiol 2019;40:1112–16, 10.3174/ajnr.A6105.
  20. Larsen N, von der Brelie C, Trick D, et al. Vessel wall enhancement in unruptured intracranial aneurysms: an indicator for higher risk of rupture? High-resolution MR imaging and correlated histologic findings. AJNR Am J Neuroradiol 2018;39:1617–21, 10.3174/ajnr.A5731.
  21. Sato T, Matsushige T, Chen B, et al. Wall contrast enhancement of thrombosed intracranial aneurysms at 7T MRI. AJNR Am J Neuroradiol 2019;40:1106–11, 10.3174/ajnr.A6084.
  22. Zeiler SR, Qiao Y, Pardo CA, et al. Vessel wall MRI for targeting biopsies of intracranial vasculitis. AJNR Am J Neuroradiol 2018;39:2034–36, 10.3174/ajnr.A5801.
  23. Zhu C, Tian X, Degnan AJ, et al. Clinical significance of intraplaque hemorrhage in low- and high-grade basilar artery stenosis on high-resolution MRI. AJNR Am J Neuroradiol 2018;39:1286–92, 10.3174/ajnr.A5676.

Image from: Vergouwen MDI, Backes D, van der Schaaf IC, et al. Gadolinium enhancement of the aneurysm wall in unruptured intracranial aneurysms is associated with an increased risk of aneurysm instability: a follow-up study. AJNR Am J Neuroradiol 2019;40:1112–16, 10.3174/ajnr.A6105.