PMC7293727_01
Imaging of the right ear showing enlarged emissary veins (arrows). (a), (b) Coronal HRCT. (c) Axial HRCT. (d) Axial HRCT (mIP), showing small posterior condylar emissary canal on the left (jugular bulb type) and groove on the right (occipital sinus type):arrows; atresic jugular foramen:arrow heads. HRCT: high-resolution computed tomography; mIP: maximum intensity projection.
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A preoperative high-resolution computed tomography (HRCT) scan was suggestive of bilateral superior semicircular canal dehiscence and showed a bilateral jugular bulb and foramen aplasia, a persistent petrosquamous sinus, and multiple vascular impressions in the middle cranial fossa, the latter causing a tortuous tubular images projecting in the proximity of the temporomandibular joints and separated from the superior and posterior wall of the external ear canal by only a thin bony lamella (Figures 1(a)-1(c).
Lateral scanogram: irregular thickness in the calvarium contour suggestive of a previous cranioplasty in childhood due to craniossinostosis.
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Irregular thickness in the calvarium contour suggestive of a previous cranial surgery was also identified on CT scans (Figure 2).
MRV; (a), (b) right circulation, (c) left circulation. MRV: magnetic resonance venography.
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It further identified a bilateral persistent petrosquamous sinus (draining into a retromandibular vein, via retroauricular foramen and pterygoid plexus, and via foramen oval), a posterior condylar emissary vein (draining into the external vertebral venous plexus and via condylar foramen), a mastoid emissary vein (draining into the posterior auricular vein and mastoid foramen) and an occipital emissary vein (draining into the suboccipital plexus) (Figures 3(a)-3(c); Figures 4(a) and 4(b); and Figures 5(a) and 5(b)).
Sagital MRV broad (a) and detailed (b) mIP, depicting right emissary mastoid vein (blue) draining right sigmoid sinus into posterior auricular vein and suboccipital plexus.
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It further identified a bilateral persistent petrosquamous sinus (draining into a retromandibular vein, via retroauricular foramen and pterygoid plexus, and via foramen oval), a posterior condylar emissary vein (draining into the external vertebral venous plexus and via condylar foramen), a mastoid emissary vein (draining into the posterior auricular vein and mastoid foramen) and an occipital emissary vein (draining into the suboccipital plexus) (Figures 3(a)-3(c); Figures 4(a) and 4(b); and Figures 5(a) and 5(b)).
Axial MRV (a) and HRCT mIP (b) showing striking asymmetry in the petrosquamosal sinuses (PSS) and canals, bilaterally (blue); middle meningeal sinus (green) draining into the cavernous sinus (arrow) and pterygoid venous plexus (arrow head) via the foramen ovale; retromandibular vein (orange) draining into external jugular vein; mastoid emissary vein (white) posterior to PSS.
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It further identified a bilateral persistent petrosquamous sinus (draining into a retromandibular vein, via retroauricular foramen and pterygoid plexus, and via foramen oval), a posterior condylar emissary vein (draining into the external vertebral venous plexus and via condylar foramen), a mastoid emissary vein (draining into the posterior auricular vein and mastoid foramen) and an occipital emissary vein (draining into the suboccipital plexus) (Figures 3(a)-3(c); Figures 4(a) and 4(b); and Figures 5(a) and 5(b)).