Medical Image of the Week: Moyamoya Disease

Figure 1. Cerebral angiogram of the brain demonstrating bilateral high-grade stenosis of the anterior and middle cerebral arteries, worse on the left.

Figure 2. Magnetic resonance imaging showing multiple punctate infarcts in the frontal and parietal lobes on the left side.

A 52-year-old, right-handed, Caucasian woman with a history of hypertension and morbid obesity presented with acute onset of word-finding difficulty and slurred speech. Her medical and family history was negative for cerebral vascular event, coronary artery disease or smoking. Computed tomography of the patient's brain showed narrow caliber middle cerebral artery vasculature bilaterally. This abnormal finding prompted further investigation with cerebral angiogram. The angiogram showed bilateral high-grade stenosis of the anterior and middle cerebral arteries, worse on the left (Figure 1). Magnetic resonance imaging revealed multiple left sided punctate infarcts in the frontal and parietal lobes (Figure 2). Diagnosis of ischemic stroke secondary to moyamoya disease was established. This patient was not a candidate for fibrinolytic therapy since it had been more than 4 hours from initial presentation. She was treated with aspirin, clopidogrel, and atorvastatin for secondary prevention of ischemic stroke. Two months after her discharge date, the patient had a middle cerebral artery to superior temporal artery bypass on the left side, followed by a middle cerebral artery to superior temporal artery bypass on the right two months after initial bypass. Patient progressed to an uneventful recovery. Discharge planning included the continuation of aspirin, clopidogrel, and atorvastatin indefinitely.

Moyamoya disease (MMD) is an uncommon vasculopathy of unknown origin associated with diverse risk factors (1). It was first discovered in a Japanese population, and reported more commonly in this sub-population. However, numerous cases were reported across the globe (2). Moyamoya disease associated with other systemic condition such as neurofibromatosis type 1, trisomy 21, thyroid cranial irradiation or thyroid disease is termed moyamoya syndrome (MMS) (1,2). Moyamoya syndrome is a cerebrovasculopathy originating from collateral flow that develops secondary to occlusion of the internal carotid artery and the proximal afferent vessels at the circle of Willis (3). MMS can have abrupt or insidious onset and may progress to diversifying cerebral ischemic stroke or to intracranial hemorrhage, which is a worse prognosis and the primary cause of death in patients with MMD (4). It has been shown that ischemic stroke associated with MDD or MMS usually occurs when compensatory collateral vessels are unable to supply sufficient blood to the brain after occlusion or stenosis of the internal carotid arteries or its tributary vessels (5,6). On the other hand, intracranial hemorrhage occurs secondary to the rupture of abnormal moyamoya vessels (7,8).

It is imperative to differentiate between non-hemorrhagic and hemorrhagic moyamoya. Neuroimaging is the preferred method of diagnosis after high clinical suspicion of MMD or MMS. Intracranial hemorrhage and cerebral infarction can be diagnosed with computed tomography and magnetic resonance imaging/ cerebral angiogram, respectively (8,9). Recent use of magnetic resonance perfusion imaging has been shown to be crucial in diagnostics and medical-surgical decision making. There is no common consensus when it comes to treatment of moyamoya at this time. Initial management is symptomatic with anticoagulants, antiplatelet and corticosteroids (10). Treatment options may also include direct or indirect surgical revascularization as optimal therapy (11,12).

Stella Pak MD, Kokou Adompreh-Fia MD, Damian Valencia MD, Adam Fershko MD, and Jody Short DO.

Department of Medicine

Kettering Medical Center

Kettering, OH USA

References

1. Phi JH, Wang KC, Lee JY, Kim SK. Moyamoya Syndrome: A window of moyamoya disease. J Korean Neurosurg Soc. 2015 Jun;57(6):408-14. [CrossRef] [PubMed]
2. Suzuki J, Takaku A. Cerebrovascular "moyamoya" disease. Disease showing abnormal net-like vessels in base of brain. Arch Neurol. 1969 Mar;20(3):288-99. [CrossRef] [PubMed]
3. Yamamoto, S, Koh M, Kashiwazaki D, Akioka N, Kuwayama N, Noguchi K, Kuroda S. Is Quasi-moyamoya disease a uniform disease entity? A three-dimensional constructive interference in steady state imaging study. J Stroke Cerebrovasc Dis. 2016 Jun;25(6):1509-16. [CrossRef] [PubMed]
4. Baba, T., Houkin, K. Kuroda. Novel epidemiological features of moyamoya disease. J Neurol Neurosurg Psychiatry. 2008 Aug;79(8):900-4. [CrossRef] [PubMed]
5. Miyamoto S, Kikuchi H, Karasawa J, Nagata I, Ihara I, Yamagata S. Study of the posterior circulation in moyamoya disease. Part 2: Visual disturbances and surgical treatment. J Neurosurg. 1986 Oct;65(4):454-60. [CrossRef] [PubMed]
6. Kuroda S, Ishikawa T, Houkin K, Iwasaki Y. Clinical significance of posterior cerebral artery stenosis/occlusion in moyamoya disease. No Shinkei Geka. 2002 Dec;30(12):1295-300. [PubMed]
7. Kang K, Lu J, Zhang D, Li Y, Wang D, Liu P, Li B, Ju Y, Zhao X. Difference in cerebral circulation time between subtypes of moyamoya disease and moyamoya syndrome. Sci Rep. 2017;7(1):2587. [CrossRef] [PubMed]
8. Lui, P, Han C, Li DS, Lv XL, Li YX, Duan L. Hemorrhagic moyamoya disease in children: Clinical, angiographic features, and long-term surgical outcome. Stroke. 2016 Jan;47(1):240-3. [CrossRef] [PubMed]
9. Kellner CP, McDowell MM, Phan MQ, Connolly ES, Lavine SD, Meyers PM, Sahlein D, Solomon RA, Feldstein NA, Anderson RC. Number and location of draining veins in pediatric arteriovenous malformations: association with hemorrhage. J Neurosurg Pediatr. 2014 Nov;14(5):538-45. [CrossRef] [PubMed]
10. Whitaker J. Management of moyamoya syndrome [comment]. Arch Neurol. 2001;58:132. [CrossRef] [PubMed]
11. Golby AJ, Marks MP, Thompson RC, Steinberg GK. Direct and combined revascularization in pediatric moyamoya disease. Neurosurg. 1999;45:50-8. [PubMed]
12. Mizoi K, Kayama T, Yoshimoto T, Nagamine Y. Indirect revascularization for moyamoya disease: is there a beneficial effect for adult patients? Surg Neurol. 1996;45:541-8. [CrossRef] [PubMed] 

Cite as: Pak S, Adompreh-Fia K, Valencia D, Fershko A, Short J. Medical image of the week: moyamoya disease. Southwest J Pulm Crit Care. 2017;15(5):227-9. doi: https://doi.org/10.13175/swjpcc136-17 PDF

Medical Image of the Week: Artery of Percheron Infarction

 

Figure 1. T2 weighted MRI demonstrating bilateral infarcts of the rostral midbrain (A, orange box) and thalami (B, orange box).

 

Figure 2. CT angiogram of posterior cerebral artery circulation demonstrating normal vascularization (A) and artery of Percheron (B, white arrow) (1).

A 55-year-old African-American man presented to the Emergency Department for acute altered mental status which started 4 hours ago. His medical history was significant for heart failure with reduced ejection fraction, diabetes mellitus, marijuana and opioid use. On admission, the patient appeared to be in a deep sleep, unarousable, with grimacing to noxious stimuli. He occasionally moved all extremities. He was intubated for airway protection. Initial CT head non-contrast demonstrated a previous right MCA infarct, with no new acute hemorrhage. MRI/MRA brain revealed complete infarction of the artery of Percheron (AOP), likely due to a left ventricular thrombus (Figure 1). The patient remained somnolent throughout hospitalization with minimal neurologic improvement, and was ultimately transferred to a long-term care facility after a tracheostomy and PEG placement.

The artery of Percheron is a rare, normal intracranial vascular variant in which a single arterial trunk originates from the posterior cerebral artery, giving rise to the vascular supply of both thalami and upper midbrain (Figure 2) (2). Acute occlusion of the artery results in posterior circulation infarction and is associated with impairment of consciousness, sleep and alertness. Diagnosis is usually based on magnetic resonance imaging demonstrating bilateral thalami and midbrain infarct. Management primarily consists of supportive measures, as reperfusion of cerebral microvascular carries significant surgical risk. Given the rarity of incidence, the prognosis of AOP infarct is unknown (3).

TC Ta¹, ET Vo¹, KS Goldlist², B Barcelo¹, JM Dicken³

¹Department of Internal Medicine

²Department of Internal Medicine at University of Arizona at South Campus

³University of Arizona College of Medicine.

University of Arizona

Tucson, AZ USA

References

1. Shetty A, Jones J. Artery of Percheron. Radiopedia. Available at: https://radiopaedia.org/articles/artery-of-percheron (accessed 3/24/17).
2. Lazzaro NA, Wright B, Castillo M, et al. Artery of Percheron infarction: imaging patterns and clinical spectrum. AJNR Am J Neuroradiol. 2010 Aug;31(7):1283-9. [CrossRef] [PubMed]
3. Amin OS, Shwani SS, Zangana HM, Hussein EM, Ameen NA. Bilateral infarction of paramedian thalami: a report of two cases of artery of Percheron occlusion and review of the literature. BMJ Case Rep. 2011 Mar 3;2011. [CrossRef] [PubMed] 

Cite as: Ta TT, Vo ET, Goldlist KS, Barcelo B, Dicken JM. Medical image of the week: artery of Percheron infarction. Southwest J Pulm Crit Care. 2017;14(3):127-8. doi: https://doi.org/10.13175/swjpcc037-17 PDF 

Medical Image of the Week: Subarachnoid Hemorrhage

Figure 1. Axial CT of the head without contrast demonstrates a large subarachnoid hemorrhage in the basal cisterns and adjacent to the insular cortices (blue arrows).

Figure 2. Coronal CT angiogram of the head demonstrates a saccular outpouching of the anterior communicating artery (blue arrow) consistent with an aneurysm.

A 70-year-old lady with a past medical history of hypertension and dyslipidemia was brought in by her family members for evaluation of confusion and headache for 1 week. There was no history of recent trauma or falls. There was no known family history of aneurysm or sudden death. On examination, her blood pressure was 139/99 mmHg, heart rate 92 bpm, afebrile and respiratory rate was 13 breaths per minute. She was alert but only oriented to self. Pupils were symmetric and reactive to light. She was able to follow commands and power was symmetric in all limbs.

CT of the head without contrast showed diffuse subarachnoid and intraventricular hemorrhage with signs of raised intracranial pressure (Figure 1). Neurosurgery was consulted and she underwent emergent insertion of an external ventricular drain. Head CT post-ventriculostomy showed improvement in her ventricular dilatation. CT angiography was performed later and showed an anterior communicating artery aneurysm (Figure 2), thought to be culprit of her subarachnoid hemorrhage. Craniotomy with surgical clipping was performed. This was followed by improvement in her mental status.

The common presenting symptom of patients with subarachnoid hemorrhage is headache. They will classically describe it as "worst headache of my life". This can be accompanied by altered mental status, nausea, vomiting, or meningeal signs. Head CT without contrast should be obtained immediately if there is suspicion of subarachnoid hemorrhage. Studies have shown that head CT is extremely sensitive if obtained within 6 hours of clinical presentation but its sensitivity declines over time (1). Lumbar puncture should be performed if head CT is negative but there is strong suspicion of subarachnoid hemorrhage. A combination of negative head CT and lumbar puncture is sufficient to rule out subarachnoid hemorrhage in a patient presented with headache (2).

Kai Rou Tey¹, MD; Tammer Elaini², MD

¹Department of Internal Medicine, University of Arizona College of Medicine- South Campus and ²Department of Pulmonary, Critical Care, Allergy and Sleep University of Arizona College of Medicine

Tucson, AZ USA

References

1. Perry JJ, Stiell IG, Sivilotti ML, et al. Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. BMJ. 2011;343:d4277. [CrossRef] [PubMed]
2. Perry JJ, Spacek A, Forbes M, et al. Is the combination of negative computed tomography result and negative lumbar puncture result sufficient to rule out subarachnoid hemorrhage? Ann Emerg Med. 2008 Jun;51(6):707-13. [CrossRef] [PubMed] 

Cite as: Tey KR, Elaini T. Medical image of the week: subarachnoid hemorrhage. Southwest J Pulm Crit Care. 2016;13(2):88-9. doi: http://dx.doi.org/10.13175/swjpcc063-16 PDF