Asymmetry of Deep Medullary Veins on Susceptibility Weighted MRI in Patients with Acute MCA Stroke Is Associated with Poor Outcome

<div><p>Background and Purpose</p><p>Due to its sensitivity to deoxyhemoglobin, susceptibility weighted imaging (SWI) enables the visualization of deep medullary veins (DMV) in patients with acute stroke, which are difficult to depict under physiological circumstances. This study assesses the asymmetric appearance of prominent DMV as an independent predictor for stroke severity and outcome.</p><p>Materials and Methods</p><p>SWI of 86 patients with acute middle cerebral artery (MCA) stroke were included. A scoring system from 0 (no visible DMV) to 3 (very prominent DMV) was applied for both hemispheres separately. A difference of scores between ipsi- and contralateral side was defined as asymmetric (AMV+). Occurrence of AMV+ was correlated with the National Institute of Health Stroke Scale (NIHSS) Score on admission and discharge, as well as the modified Rankin Scale (mRS) at discharge. Ordinal regression analysis was used to evaluate NIHSS and mRS as predictors of stroke severity, clinical course of disease and outcome.</p><p>Results</p><p>55 patients displayed AMV+ while 31 did not show an asymmetry (AMV–). Median NIHSS on admission was 17 (11–21) in the AMV+ group and 9 (5–15) in the AMV– group (p = 0.001). On discharge median NIHSS was 11 (5–20) for AMV+ and 5 (2–14) for AMV– (p = 0.005). The median mRS at discharge was 4 (3–5) in the AMV+ group and 3 (1–4) in AMV– (p = 0.001). Odds ratio was 3.19 (95% CI: 1.24–8.21) for AMV+ to achieve a higher mRS than AMV– (p = 0.016).</p><p>Conclusion</p><p>The asymmetric appearance of DMV on SWI is a fast and easily evaluable parameter for the prediction of stroke severity and can be used as an additional imaging parameter in patients with acute MCA stroke.</p></div

Scoring system for the quantification of DMV.

<p>A) 0 = no visible DMV B) 1 = faintly visible DMV C) 2 = unequivocal visible DMV D) 3 = very prominent DMV.</p

Patient with right MCA infarction.

<p>A) Reduced perfusion within the territory of the right MCA. B) Asymmetric appearance of prominent periventricular DMV within the infarcted area (arrows).</p

Clinical and demographic features of AMV+ and AMV–.

<p>Clinical and demographic features of AMV+ and AMV–.</p

Endovascular treatment success in AMV+ and AMV–.

<p>No. successfully treated/total no. of patients, (%).</p><p>Endovascular treatment success in AMV+ and AMV–.</p

Parameters of the used MRI sequence.

<p>Parameters of the used MRI sequence.</p

Bland-Altman plots show the differences between the measurements on LCR and lateral MRI cephalograms.

<p>Solid lines represent the mean of all differences (bias), dashed lines represent the 95% limits of agreement. Exemplary measurements according to Steiner’s analysis [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0174524#pone.0174524.ref014" target="_blank">14</a>] are shown in this figure: (a) SNA-angle, (b) SNB-angle, (c) ANB-angle, (d) SND-angle, (e) Ui/NA-angle, (f) Is/NA-distance, (g) Li/NB-angle, (h) Ii/NB-distance, (i) Pg/NB-distance, (j) Ui/Li-angle, (k) SN/OcP-angle and (l) SN/GoGn-angle.</p

Lateral cephalometric measurements from LCR and MRI (n = 20).

<p>Lateral cephalometric measurements from LCR and MRI (n = 20).</p

Cephalometric landmarks used in the present study.

<p>A total of 10 midsagittal (blue marked) and 8 bilateral (red marked) landmarks were included in cephalometric analysis: S = Sella; N = Nasion; ANS = Anterior nasal spine; PNS = Posterior nasal spine; A = Point A (most concave point of anterior maxilla); B = Point B (most concave point of mandibular symphysis); Is = Incision superius; Ii = Incision inferius; As = Apex superius; Ai = Apex inferius; Pg = Pogonion (most anterior point of mandibular symphysis); Gn = Gnathion (midpoint between Pg and Me); Me = Menton (most inferior point of mandibular symphysis); D = Point D (geometric center of the symphysis); Go = Gonion; tGo = Gonion tangent point (intersection between the mandibular line and the ramus line); Ar = (junction between inferior surface of the cranial base and the posterior border of the ascending rami of the mandible); ppOcc = posterior point of occlusion.</p

Workflow applied in the present study for each patient (n = 20) is shown.

<p>I = A multiplanar reconstruction (MPR) along the anatomic sagittal plane was acquired from primary magnetic resonance imaging (MRI) datasets. II = The midsagittal plane is coloured in red for better visualization of the workflow. Nine slices containing the landmarks necessary for cephalometric analysis were selected (1). The paired lateral slices were cropped preserving the relevant landmarks on the left (2a) and right (2b) side. The midsagittal plane and the 8 cropped lateral slices were merged into a lateral MRI cephalogram (3). III = Lateral cephalometric analysis was performed on lateral MRI cephalograms and corresponding lateral cephalometric radiographs (LCR) with dedicated software. For each modality two observers placed 10 midsagittal and 8 bilateral landmarks from which 14 angles and 10 distances were calculated automatically by software. Measurements were taken twice with an interval of 4 weeks.</p