intracranial bleeding in hemorrhagic - type moyamoya disease can arise either from the fragile moyamoya vessels or from peripheral artery pseudoaneurysms located within deep collaterals . when the weak spots are located at tributaries of the choroidal arteries , they are regarded as major sources of intraventricular hemorrhage ( ivh ) . the ideal therapeutic strategy for hemorrhagic - type moyamoya disease is to obliterate the bleeding source before conducting a revascularization procedure in order to prevent early re - rupture . however , owing to multiple factors , direct surgical or endovascular obliteration of the bleeding source is not always feasible . surgical revascularization alone is considered effective in preventing re - rupture from moyamoya collaterals , but its role as the primary treatment for ruptured weak points arising from choroidal arteries is less clear . in this report , we presented a hemorrhagic - type moyamoya patient who harbored multiple weak spots in a single acha , the artery responsible for the hemorrhage . we described our rationale when the precise point of rupture was not able to be identified , and demonstrated the efficacy of surgical revascularization to address such a clinical scenario . a 20-year - old female patient was admitted with a sudden onset of severe headache . neurological examination revealed no neurological deficits , but brain computed tomography ( ct ) revealed an ivh mainly on the left side ( fig . this finding indicated that the bleeding point was more likely located on the choroidal arteries . perfusion ct further demonstrated a relative hypoperfusion status in the left hemisphere , as evidenced by an increased mean transit time ( mtt ) in the left fronto - parietal region ( fig . an external ventricular drain was placed on the right side to decompress the ventricle . figure  1:(a ) ct scan showed primary ivh predominantly on the left lateral ventricle . ct perfusion maps demonstrated symmetric cerebral blood flow ( b ) and cerebral blood volume ( c ) , but an increased mtt on the left side ( d ) , indicative of a relative hypoperfusion on the left hemisphere . ct perfusion maps demonstrated symmetric cerebral blood flow ( b ) and cerebral blood volume ( c ) , but an increased mtt on the left side ( d ) , indicative of a relative hypoperfusion on the left hemisphere . cerebral digital subtracted angiography ( dsa ) revealed typical angiographic findings of moyamoya disease , which included bilateral stenosis in the terminal portion of the internal carotid arteries ( icas ) and formation of abnormal vascular networks in the region of the choroidal arteries and basal ganglia ( fig . the acha on the left side was significantly enlarged , and provided collateral supply toward the periventricular brain parenchyma . multiple angiographic weak points , characterized by irregular segmental dilatations and pseudoaneurysmal formation , were also noted along the intraventricular segment of the acha ( fig . 2b ) . 
 figure  2:anteroposterior ( a ) and lateral ( b ) views of the right ica angiogram demonstrated severe stenosis of the ica termination , formation of moyamoya collateral network and multiple weak spots ( dashed arrows : irregular segmental dilatations ; single arrow : pseudoaneurysm ) along the enlarged intraventricular segment of acha . ( c ) right external carotid angiogram demonstrated a robust collateral formation ( asterisk ) underlying the site of pial synangiosis . ( d ) right ica angiogram demonstrated that previous weak spots observed along the intraventricular acha segment ( double arrows ) significantly regressed or disappeared . anteroposterior ( a ) and lateral ( b ) views of the right ica angiogram demonstrated severe stenosis of the ica termination , formation of moyamoya collateral network and multiple weak spots ( dashed arrows : irregular segmental dilatations ; single arrow : pseudoaneurysm ) along the enlarged intraventricular segment of acha . ( c ) right external carotid angiogram demonstrated a robust collateral formation ( asterisk ) underlying the site of pial synangiosis . ( d ) right ica angiogram demonstrated that previous weak spots observed along the intraventricular acha segment ( double arrows ) significantly regressed or disappeared . as all these observed weak spots might be the source of the hemorrhage , the precise bleeding point could not be identified . in addition , trapping of the whole intraventricular acha segment also carried a risk of interruption of this important collateral supply . therefore , our treatment strategy was to perform an indirect surgical revascularization on the left hemisphere first in order to decrease collateral needs from the acha . an additional neuroendovascular occlusion of the distal acha could be considered later if the weak points failed to regress . an encephalo - duro - arterio - synangiosis procedure was performed on the left hemisphere . dsa 1 year after surgery demonstrated robust collateral formation underlying the site of pial synangiosis ( fig . all weak points observed along the acha had markedly decreased in caliber or disappeared ( fig . therefore , additional treatment was not necessary , and the patient remained symptom - free for 4 years . the patient has consented to the submission of the case report for submission to the journal . this case report has been approved by our local institutional review board ( cgh - p104079 ) . in adult moyamoya disease , collaterals are prone to arise more often from the choroidal arteries . hemodynamic overload of choroidal arteries makes these vessels enlarged and more fragile , and the resulting development of weak spots , which arise more often at intraventricular rather than cisternal segments , explains anatomically why these patients present primarily with ivh . hence , as in our case , neurosurgeons should look for the possible presence of rupture points on the intraventricular segments of the choroidal arteries when moyamoya patients present with ivh . before conducting a revascularization procedure , identification and obliteration of the bleeding source should be considered first in order to prevent re - rupture . open craniotomy is the traditional treatment of choice , because both bleeding point obliteration and a revascularization procedure can be performed in the same session . however , owing to the deep location of the affected collateral vessels , open craniotomy often poses a greater risk of parenchymal damage . neuroendovascular approach was an alternative , which involves either bleeding point obliteration with parent vessel preservation or parent vessel occlusion . in our case , however , direct rupture point targeting with acha preservation was not feasible , because the precise source of rupture was indistinguishable . direct acha trapping was also too risky , because it would interrupt this important collateral supply . in other words , direct obliteration of the bleeding source in our case was not a viable option . another treatment option in this clinical scenario was to perform surgical revascularization alone , which theoretically would allow gradual reduction of the hemodynamic stress on deep collaterals and regression of its associated weak points within 612 months postoperatively . however , otawara et al .   reported one case in which the pseudoaneurysm did not regress , but instead ruptured 10 years after the revascularization surgery . this report reminded us that revascularization alone is not always effective in dealing with weak spots on deep collateral vessels . a follow - up dsa is mandatory in order to determine both the robustness of the collateral network established by the bypass graft and the fate of the observed weak points . in our case , when synangiosis collaterals form well but weak spots fail to regress within 612 months , neuroendovascular trapping of the intraventricular acha segment could be considered as a rescue procedure , given that the acha is no longer acting as an important collateral source . in conclusion , the presence of multiple weak spots without a distinguishable source of rupture poses a specific challenge in the treatment of hemorrhagic - type moyamoya disease . we demonstrated that , without direct rupture point obliteration , a successful cerebral revascularization procedure had a chance to promote gradual regression of the weak spots . however , follow - up dsa was mandatory in order to determine both the robustness of the collateral network underlying the revascularization site and the fate of the observed weak points .
a 20-year - old female with moyamoya disease presented with acute intraventricular hemorrhage . 
 cerebral angiography demonstrated that the anterior choroidal artery ( acha ) was responsible for the bleeding , but the precise point of rupture was unpredictable , because multiple angiographic weak spots were found on the artery . as direct targeting of the rupture point was unfeasible , we performed encephalo - duro - arterio - synangiosis to decrease the hemodynamic overload on the acha . 
 this revascularization procedure alone successfully induced the regression of all weak points . in this report , we demonstrated that , when direct targeting of weak points was not feasible , a revascularization procedure was an acceptable alternative .