42 Left Internal Carotid Artery Aplasia as an Incidental Diagnosis in Optic Neuritis in Lupus Erythematosus

Case 42


Left Internal Carotid Artery Aplasia as an Incidental Diagnosis in Optic Neuritis in Lupus Erythematosus


Clinical Presentation


A 48-year-old otherwise healthy woman was admitted with persistent left-sided blurry vision which began 1 day prior to presentation. She had no vascular risk factors and did not suffer from migraines. Neurologic examination on admission revealed reduced visual acuity restricted to the left side.


Suspected Diagnosis


Left-sided optic neuritis.


Initial Neuroradiologic Findings


MRI FLAIR- and T2-weighted images showed no parenchymal lesions. Incidentally, a missing left carotid siphon signal void was noticed on axial T2-weighted images. Subsequently performed intracranial time-of-flight (TOF) and contrast enhanced (ce) MR angiography (MRA) showed agenesis of the left internal carotid artery (ICA). Intracranially, the left middle cerebral artery (MCA) and anterior cerebral artery (ACA) were connected with the left posterior cerebral artery (PCA) via a large posterior communicating artery (PCoA), which was functioning as a “reversed” fetal-type variant. The anterior communicating artery (ACoA) was missing. The external carotid artery (ECA) course was in continuity with the common carotid artery (CCA). In addition, a direct origin of the left vertebral artery (VA) from the aortic arch was present (Fig. B42.1, Fig. B42.2, Fig. B42.3).


Questions to Answer by Ultrasound Techniques



  • Could the presumed ICA agenesis be confirmed?
  • If so, could the atypical left MCA and ACA blood supply via the PCoA be confirmed?
  • If ICA aplasia was present, what was the blood supply of the ophthalmic artery?

Initial Neurosonologic Findings


Extracranial Duplex Sonography


B-mode imaging revealed no atherosclerotic vascular changes and no signs of vessel dissection. The diameter of the right CCA was larger (5.9 mm) than the left CCA (3.4 mm). The left ICA was completely missing. Doppler spectrum analysis of both CCAs and ECAs revealed normal findings. Blood volume flow (BVF) in the right ICA (320 mL/min) and in the right V2-VA (170 mL/min) was within normal ranges. The left V2-VA BVF yielded raised values of 280 mL/min, resulting in a normal global BVF = CBF of 770 mL/min (Fig. B42.4, Fig. B42.5, Fig. B42.6, Fig. B42.7, Fig. B42.8).


Transcranial Duplex Sonography


Left-sided transtemporal axial insonation revealed a prominent signal in projection of the PCoA with a flow direction toward the anterior circulation. Contralateral insonation also delineated the prominent left PCoA with a blue-coded vessel signal providing blood flow toward the left anterior circulation. Normal blood flow parameters were seen bilaterally in all basal cerebral arteries including the left PCoA. Transorbital insonation showed a normal antegrade flow and flow velocities within normal ranges in both ophthalmic arteries (OAs). Both middle meningeal arteries (MMAs) were examined to analyze their potential roles in supplying the OA. Both vessels were detectable. A higher flow velocity was seen in the left MMA (23/8 cm/s versus 15/6 cm/s) indicating that the ipsilateral MMA supplied the left OA (Figs. B42.9–B42.18).


Fig. B42.19 shows a schematic of the patient’s extra-and intracranial brain-supplying arteries.


Conclusion


Agenesis of the left ICA with intracranial blood supply of the left MCA and ACA from the left PCA. Left OA blood supply probably via the left MMA.












Jun 20, 2018 | Posted by in NEUROSURGERY | Comments Off on 42 Left Internal Carotid Artery Aplasia as an Incidental Diagnosis in Optic Neuritis in Lupus Erythematosus
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