Case 13 A 51-year-old woman presented with stepwise deterioration of a left hemiparesis that had started 3 days before admission. The medical history revealed chronic rhinitis, sinusitis, and bronchitis but no vascular risk factors. On neurologic examination, the patient had a severe left-sided brachiofacial hemiparesis (National Institutes of Health Stroke Scale [NIHSS] score: 8). In addition, she had nasal congestion. Cerebral CT (CCT) scan on the day of admission revealed ischemic infarction in the anterior and posterior territories of the right middle cerebral artery (MCA). MRI was not performed (Fig. B13.1). Ischemic brain infarction in the right MCA territory of unknown origin. B-mode sonography revealed only mild atherosclerosis of the carotid arteries. Color imaging showed elongation and caliber variations of both distal ICAs, but predominantly affecting the right side. Blood flow velocity in the proximal right ICA was mildly reduced (flow velocity: 47/24 cm/s) and the pulsatility slightly increased. Within the distal segment of the right ICA, a non-angle-corrected peak systolic flow velocity of 250 cm/s was observed. Normal flow velocities were seen in the remaining extracranial vessels (Fig. B13.2 and Fig. B13.3). The temporal window was inadequate for a complete insonation of the anterior circulation. Punctual signals of the proximal M1-MCA could be obtained, revealing an obvious flow velocity difference between the two sides (flow velocity: right M1-MCA, 57/25 cm/s; left M1-MCA, 111/55 cm/s) (not shown). The calculated Zanette asymmetry index for the systolic velocities was 64 and the right-to-left ratio (= velocity of the affected M1/normal M1 velocity) was 0.51. Assessment of the other intracranial vessels showed normal and symmetric flow signals. Distal extracranial right ICA stenosis, ~70%. Suspected right distal M1-MCA occlusion, probably embolic in nature. Thrombolysis was not indicated because of the time delay and the signs of infarction on CT. The above vascular changes in a relatively young patient without classic vascular risk factors did not favor an atherosclerotic etiology. In particular, no arterial hypertension was present. Normal 24-hour ECG and echocardiography made a cardioembolic source unlikely. There was no coagulopathy involving proteins C and S, anticardiolipin antibodies, activated protein C resistance, and lupus inhibitor. The cerebrospinal fluid (CSF) was normal. In view of the history of chronic rhinitis, sinusitis, and bronchitis, specific laboratory tests were performed which revealed an increased erythrocyte sedimentation rate (ESR) (70 mm/hour, Westergren), mild anemia, and thrombocytosis of 1,200/nL (normal range 130–340/nL), but normal white blood cell counts. In addition, the level of cytoplasmic antineutrophilic cytoplasmic antibody (cANCA) was increased to 98 E/mL (normal value <15 E/mL), and urine proteins and erythrocytes were elevated. Finally, a nasal mucosa biopsy confirmed granulomatosis with polyangiitis (GPA; formerly known as Wegener’s granulomatosis). Digital subtraction angiography (DSA) was performed to examine the presumed ICA stenosis and to rule out vasculitis. Multiple irregular concentric constrictions with normal and dilated intervening segments were found in both distal extracranial ICAs, though predominantly affecting the right side. This “string of beads” pattern led to the diagnosis of fibromuscular dysplasia (FMD) (Fig. B13.4 and Fig. B13.5). Mild caliber variations were also seen in the left distal vertebral artery (VA) and the right renal artery. The intracranial vessels, in particular the MCA branches, were not affected. Dissection and vasculitis were excluded. A recurrent artery-to-artery embolism from the greater affected right ICA was assumed to be the most likely cause of the stroke. Antiplatelet therapy was therefore commenced for secondary stroke prevention. Interventional treatment by stenting or surgery was not recommended because of the complex vessel pathology and GPA. The GPA was treated with cyclophosphamide and corticosteroids. A clinical follow-up 6 months after the initial presentation showed only a minor improvement of the hemiparesis. ESR and cANCA had normalized during the immunosuppressive therapy. Cranial CT scan showed the residual large ischemic MCA territory infarction (Fig. B13.6). On this occasion MRI was also performed which demonstrated Wallerian degeneration of the pyramidal tract up to the pyramidal decussation (Fig. B13.7). The patient remained asymptomatic over the subsequent 5 years. Fig. B13.1 Unenhanced CT, axial plane. Ischemic infarction in the right anterior and posterior MCA territories (arrows). (Reproduced from Braun et al. One stroke — two triggers. J Neurol 2006;253:1356–1357, with permission of Springer.) B-mode sonography revealed unchanged mild atherosclerosis of the carotid arteries. In the right common carotid artery (CCA), a high-resistance flow signal was seen. The right external carotid artery (ECA) showed an “internalized” low-resistance flow signal, indicating orbital collateral flow. Doppler spectrum analysis of the proximal right ICA demonstrated a “stump signal” (Fig. B13.8 and Fig. B13.9). The transcranial bone window had further worsened. Doppler spectrum analysis of the right MCA revealed a positive oscillation effect on slight digital tapping of the left ICA at the submandibular level but not of the dominant VA at the atlas loop. The anterior communicating artery (ACoA) demonstrated turbulent flow. The remaining intracranial vessels could not be visualized. The ophthalmic arteries (OAs) were not examined. Fig. B13.2 Extracranial duplex, longitudinal plane. Slightly altered flow signal in the right proximal ICA revealing a mildly reduced velocity and mildly increased pulsatility (flow velocity 47/24 cm/s). Right ICA occlusion secondary to FMD. Suspected collateralization via the contralateral A1-ACA (cross-flow) and ipsilateral OA. Large territorial MCA infarction caused by artery-to-artery embolism originating from the right ICA that was severely affected by FMD. Thrombocytosis due to GPA may have been a predisposing cofactor. Secondarily, clinically asymptomatic right extracranial ICA occlusion. Fig. B13.3 Extracranial duplex, longitudinal plane. Color-mode imaging demonstrates elongation, caliber variations, and stenosis (arrow) of the right distal ICA. Maximum peak systolic flow velocity was 250 cm/s (not shown). Note the blue-colored internal jugular vein. Fig. B13.4 DSA, right ICA injection, posteroanterior view: Multiple irregular constrictions in a “string of beads” appearance in the right distal ICA as a characteristic, pathognomonic angiographic finding of FMD. Note the severe stenosis within the mid part of the extracranial ICA (arrowhead). Note also the extension of FMD into the proximal part of the petrous C6 segment of the ICA (arrow).
Right Internal Carotid Artery Stenosis in Fibromuscular Dysplasia and Granulomatosis with Polyangiitis (formerly Wegener’s Granulomatosis)
Clinical Presentation
Initial Neuroradiologic Findings
Suspected Diagnosis
Question to Answer by Ultrasound Techniques
Initial Neurosonologic Findings (Day 1)
Extracranial Duplex Sonography
Transcranial Duplex Sonography
Conclusion
Clinical Course (1)
Conventional Angiography (Day 5)
Clinical Course (2)
Follow-up Neurosonologic Findings (5 Years)
Extracranial Duplex Sonography
Transcranial Duplex Sonography
Conclusion
Final Diagnosis
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of Stroke
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