Moya abnormality. A non-contrast MRI brain was done on

Moya Moya disease is an entity, which
represents chronic idiopathic non-inflammatory progressive occlusion of circle
of Willis, which in course of time leads to development of collateral vessels. It
is more common in Japanese individuals.

This should be considered as a differential
in young stroke. Here we present a case of 8-year-old young female with right
hemiparesis and headache with a known history of seizure disorder.

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Keywords: Moya Moya , puff of
smoke, IVY sign

Introduction

Moya Moya is a idiopathic, chronic progressive non-atherosclerotic
Vasoocclusive disease involving circle of Willis arteries predominantly supra
clinoid Internal carotid artery with multiple collateral vessels maintaining flow.
Moya Moya is a japanese word representing puffy, hazy appearance , hence the “PUFF
OF SMOKE” appearance1. It is first reported in Japanese population in 19572.
It has bimodal age distribution: early childhood (two third cases), middle age
(one-third cases). Incidence among females is greater than that among males
(1.8:1) with japan having more prevalence than other Asian countries (0.35-2.0 cases
per 100000, prevalence 3.16) 3.10% of cases showed family history 4. Moya Moya
syndrome has similar appearance to Moya Moya disease but is associated with
other conditions like meningitis, Head trauma, Neurofibromatosis I, Down
syndrome.

Case
Report

Fig 1 and Fig 2 showing area of acute infarct in left frontal
region showing diffusion restriction (red arrow) and ADC suppression
(yellow arrow)

A
8 year old female child presented with h/o sudden onset of right upper limb
weakness with headache and photophobia. No h/o fever, vomitings, trauma. She is
a known case of seizure disorder. Laboratory investigations like CBP, CUE, homocysteine
levels, sickle cell test, antinuclear antibody test shows no abnormality. A
non-contrast MRI  brain was done on
Philips achieva 1.5T scanner.T1,T2,FLAIR,DWI/ADC maps were acquired. The
findings included an area of acute infarct in left frontal region ( fig 1 and
fig 2 ) with adjacent gliotic change.                                                    

      

                Fig 1. Axial DWI
image          Fig 2. Axial ADC image

Then a CT Cerebral angiogram with 128
slice Philips CT scanner was done with administration of 40ml contrast at flow
rate of  4ml/sec . Findings included
diffusely reduced caliber of bilateral internal carotid arteries with abrupt
cut off of distal internal carotid arteries (post supraclinoid segment) with
multiple enhancing lenticulostriate and thalamoperforator vascular channels on
right side , giving appearance of puff of smoke fig 3 and fig 4, maintaining  flow in circle of Willis with one vessel
joining left posterior cerebral artery suggesting chronic vasocclusive changes
a feature of Moya Moya disease stage II.

 

                            

                Fig 3. CT angiogram MIP coronal
image                                        Fig 4 .CT angiogram 3D volume rendered
image

Fig 3
and 4 showing multiple vascular channels (red arrow) in right basal ganglia
region representing lenticulostriate and Thalamoperforator vessels giving
characteristic PUFF OF SMOKE appearance.

An MR
angiogram was performed showing similar findings further confirming the
diagnosis by clearly depicting the abrupt cut off of internal carotid arteries fig
5 and fig 6.

           

        Fig 5.MR angiogram sagital MIP image                                 Fig 6. MR angiogram coronal MIP image

Fig 5
and 6 showing abrupt cut off of  bilateral
internal carotid arteries(red arrows) and collateral vessels in right  basal ganglia (yellow arrow)

 

 

Discussion

Moya Moya is a non inflammatory chronic
progressive occlusion of arteries of circle of Willis leading to the
development of collateral vessels seen on cerebral angiography 5. It has a
bimodal age distribution with early childhood and middle age adults representing
two third and one third cases with peaks at 4yrs and 4th decade
respectively .

 

Clinical presentation may be ischemic (more
in children),epileptic or hemorrhagic (more in adults). Behavioral disturbances
and cognitive dysfunction are uncommon symptoms and may occur based on the area
of insult 6.

 

Radiological imaging has an important
role in diagnosing Moya Moya disease. CT angiography and MR angiography are
good techniques for confirming the diagnosis. It can detect the stenosis or
occlusion of internal carotid artery with multiple collateral vessels (pial
collaterals, lenticulostraite , Thalamoperforators, leptomeningeal vessels)
with associated changes in brain like infarction and atrophy. Serpentine sulcal
high signal intensity on MRI FLAIR representing IVY sign may be identified.

Conventional angiography is the gold
standard to demonstrate Puff Of Smoke appearance .

 

Staging by SUZUKU and KODAMA is useful
in categorizing the disease into 6 phases

Stage
I  -“Narrowing of the carotid fork” , narrowed
ICA bifurcation

Stage II
-“Initiation
of the MoyaMoya” – Dilated ACA, MCA and narrowed ICA bifurcation with MoyaMoya
change

Stage
III-“Intensification
of the MoyaMoya “- further increase in MoyaMoya change of the ICA bifurcation
and

  
narrowed ACA and MCA

Stage
IV-“Minimization
of the MoyaMoya” – MoyaMoya change reducing with occlusive changes in ICA and Tenuous

   
ACA and MCA

Stage
V -“Reduction
of the MoyaMoya” – further decrease in MoyaMoya change with occlusion of
ICA, ACA and MCA

Stage
VI-“Disappearance
of the MoyaMoya” – ICA essentially disappeared with supply of brain from
ECA

 

Early diagnosis and treatment during
childhood  is essential to prevent
disability  . Acute  medical 
management include symptomatic treatment directed towards controlling seizures,
increasing cerebral blood flow 7 . Revascularization by bypass grafts from
external carotid artery to MCA or superficial temporal artery to MCA is
beneficial in ischemic cases8.

(ACA: anterior cerebral artery , MCA:
middle cerebral artery , ICA: internal carotid artery, MRI: magnetic resonance
imaging, CT: computed tomography, MIP: maximum intensity projection, CBP:
complete blood picture ,CUE: complete urine examination)