Multi-modal evaluation of haemodynamic impairments within individual watershed areas reveals increased sensitivity in unilateral carotid artery stenosis


Multi-modal evaluation of haemodynamic impairments within individual watershed areas reveals increased sensitivity in unilateral carotid artery stenosis

Kaczmarz, S.; Göttler, J.; Petr, J.; Hansen, M. B.; Kufer, J.; Zimmer, C.; Mouridsen, K.; Hyder, F.; Preibisch, C.

Purpose/Introduction: Internal carotid-artery stenosis (ICAS) is a major public health issue and causes complex haemodynamic impairments. 1–3 However, influences of microvascular effects remain poorly understood. Furthermore, increased sensitivity for regional pathophysiological changes is required to detect early disease stages.
The aim of our study was therefore to establish a multi-modal MRI protocol allowing deeper insights into the pathology. Furthermore, we hypothesize to be most sensitive to ICAS-impairments within individual watershed areas (iWSAs), which were proposed to be most vulnerable to haemodynamic compromise. 4

Subjects and Methods: Fifty-nine participants (29 unilateral ICAS-patients, age = 70.1 ± 4.8y and 30 age-matched healthy controls [HC]) underwent MRI on a Philips 3T Ingenia. The imaging protocol yielded oxygenation, perfusion and microvascular biomarkers which are summarized in Fig. 1. Additionally, iWSA’s were defined for each participant. 4 Mean haemodynamic parameter values were compared within each hemisphere of ICAS-patients vs. HC and inside vs. outside iWSAs (Fig. 2A, B) in GM and WM.

Results: Exemplary data of an ICAS-patient is shown in Fig. 2. On group-level, significant lateralisation of CBF, CVR, rCBV, CTH and OEC were found in ICAS, while rOEF was not lateralized (Fig. 3). Lateralisation was significantly enhanced inside iWSAs compared to outside of iWSAs for CBF and CVR, with a strong trend for rCBV—and strongest in WM of iWSAs (t test, p \ 0.05). OEC and CTH were indeed lateralized, but not different inside vs. outside iWSAs (Fig. 3). All HC parameters were symmetrical (data not shown).
Discussion/Conclusion: We successfully applied the proposed multimodal MRI-protocol and demonstrated its sensitivity to haemodynamic impairments in ICAS. Specificity was affirmed by symmetrical HC results. Individual parameter lateralisation in ICAS excellently agrees with the literature. Decreased CVR along with increased rCBV indicates chronic vasodilation. 1 Pronounced effects in WM-iWSA fit with the different blood supply in GM/WM. Ipsi-laterally decreased CBF, symmetrical rOEF 2 and increased CTH also coincide with recent studies 3 . The DCBF vs. DrOEF mismatch could relate to variable oxygen diffusivity 8 —potentially moderated by CTH 3, 9 . Interestingly, CTH and OEC lateralisation were iWSA-location independent, which matches previous findings. 10 These complimentary information of TTP and CTH about macrovascular effects, respectively microvascular flow 3 are highly promising to gain deeper insights into the pathology. And as initially hypothesized, evaluation within iWSA significantly increased the sensitivity to
CBF, CVR and rCBV impairments and allows to detect even subtle changes.

  • Lecture (Conference)
    ESMRMB 2019, 36th Annual Scientific Meeting, 05.10.2019, Rotterdam, Netherlands
  • Abstract in refereed journal
    Magnetic Resonance Materials in Physics, Biology and Medicine 32(2019)Suppl 1, S352-S353
    DOI: 10.1007/s10334-019-00755-1
    ISSN: 1352-8661

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Publ.-Id: 29978