basilar artery occlusion ( bao ) has been associated with a high morbidity and mortality , compromising posterior cerebral blood flow to the occipital lobes , medial temporal lobes , the thalami , the cerebellum , and the brain stem . clinical recovery is virtually impossible in the absence of recanalization . a medical emergency , bao calls for aggressive therapies to address clot dissolution , via intra - arterial thrombolysis ( iat ) , intravenous thrombolysis ( ivt ) , and/or endovascular removal . we report a case in which recanalization on mra occurs in the absence of aggressive therapy . a 58-year old patient with global left ventricular hypokinesis and wall motion abnormalities presented with acute ataxia , hemiparesis , and decreasing alertness . initial mri revealed critically decreased basilar arterial flow likely secondary to a tight stenosis versus complete occlusion of the vessel ( figure 1 ) , and multiple associated strokes in the posterior circulation distribution ( figure 2 ) . intervention with intra - arterial clot lysis and thrombolytic therapy were initially considered but the patient and family declined an interventional approach , thrombolytic therapy , or angiography . the patient was subsequently admitted to the icu , kept flat under close observation for several days , received unfractionated iv heparin , and subsequently was administered warfarin over multiple days . the patient had a follow - up mri / mra approximately 3.5 months later illustrating no new strokes and complete recanalization of the basilar artery ( figure 3 ) . he remains on warfarin , is ambulatory , lives independently , and has only a mild residual hemiparesis and ataxia . figure 1magnetic resonance angiography at onset of symptoms revealed basilar stenosis persistent with basilar artery occlusion ( arrow ) . 
  magnetic resonance angiography at onset of symptoms revealed basilar stenosis persistent with basilar artery occlusion ( arrow ) . figure 2at the time of presentation , t2 weighted imaging showed infarcts in the cerebellum ( a ) and axial flair imaging showed infarcts in the brainstem ( b ) . 
  at the time of presentation , t2 weighted imaging showed infarcts in the cerebellum ( a ) and axial flair imaging showed infarcts in the brainstem ( b ) . figure 3repeat magnetic resonance angiography 3.5 months after symptom onset revealed a complete recanalization of the previously occluded basilar artery on mra ( arrow ) . repeat magnetic resonance angiography 3.5 months after symptom onset revealed a complete recanalization of the previously occluded basilar artery on mra ( arrow ) . bao can have morbid outcomes , and mortality rate has been reportedly 8598% even with fibrinolytic , and/or endovascular therapy , if not recanalized . morbidities with thrombolysis include extracerebral hemorrhage , asymptomatic or symptomatic acute intracerebral hemorrhage , and neurological damage , most concerning of which is the  locked - in  state may occur if these therapies are not considered and bilateral infarction of the brainstem occurs . the outcome of acute bao depends on the length and location of occlusion , degree of recanalization , and time between onset of symptoms and treatment . hospital based factors are also important , in that there are a limited number of centers with interventional neuroradiologists capable of endovascular therapy . various studies have been carried out comparing the efficacy of iat versus ivt therapy , and/or endovascular management in the setting of bao , all resulting in remarkable rates of recanalization . the aggressive treatment options are associated with a significant improvement in occlusion ; ivt or iat results in about 4065% recanalization with 2224% favorable outcome . the lower improvement in morbidity and the serious risks of these therapies may be grounds for further investigation into conservative management via anti - coagulants potentially resulting in spontaneous recanalization . our patient s decision to elect medical therapy may be supported by the data of the basics study which failed to show any special benefit to ia therapy over iv therapies , with more aggressive therapies entailing greater risks . early spontaneous recanalization has been reported in the anterior cerebral circulation , whereas late spontaneous recanalization has been documented only in the extracerebral circulation . the mr angiography changes in our patient illustrate that the use of conservative treatment with unfractionated heparin in an acute setting of basilar thrombosis was associated with complete recanalization and restoration of blood flow on mra by an unknown mechanism within 3.5 months , with a good clinical outcome . there are limited , if any , documented reports of late spontaneous recanalization of the posterior cerebral circulation similar to our case in the english language literature . reports of this nature call for further investigation into the underlying mechanism of spontaneous recanalization .