Basilar Artery Dissection Complicated with Infective Endocarditis.

A 14 year-old boy developed infective endocarditis of the mitral valve caused by Methicillin-sensitive Staphylococcus aureus and became comatose. Isolated basilar artery dissection was initially observed on the 3rd day by magnetic resonance imaging (MRI), ie, it did not exist on day 1. He underwent successful urgent mitral valve repair on the 5th day because of highly mobile vegetations and a newly emerged brain infarction under optimal antibiotic administration. Postoperatively, he recovered well and the basilar artery dissection was found to have recovered on an MRI on the 25th day without any specific intervention. This clinical course indicated that intracranial artery dissection may occur as a complication of infective endocarditis and supports the importance of the careful evaluation of brain MRI in patients with infective endocarditis.

Vertebral Artery Stump Syndrome.

Carotid stump syndrome is a well-documented embolic source for ischemic stroke. However, few cases have been reported of a similar condition - termed vertebral artery stump syndrome - which affects the posterior circulation after vertebral artery origin occlusion. We herein report a case of infarction of the right superior cerebellar artery and left posterior inferior cerebellar artery territories due to vertebral artery stump syndrome. In this interesting case, a turbulent flow at the distal side of the vertebral artery occlusion was captured on ultrasonography, and was identified as the probable mechanism of vertebral artery stump syndrome.

Does Reducing the Duration from Symptom Onset to Recanalization Improve the Results of Intracranial Mechanical Thrombectomy in the Elderly?

Endovascular recanalization for acute major cerebral artery occlusion is effective within a short time after symptom onset. However, its efficacy in the elderly remains unknown. We assessed the efficacy of our comprehensive stroke center's reduction of this time in 28 consecutive patients for elderly patients (defined as patients aged ≥75 years) with acute major cerebral artery occlusion treated with intravenous injection of tissue plasminogen activator, followed by thrombus retrieval by endovascular therapy. The patients were divided into groups according to whether they were treated before implementation of the time reduction measure (from January 2012 to May 2014) or after (from June 2014 to May 2015). The onset-to-door, onset-to-needle, onset-to-recanalization (O2R), door-to-image (D2I), door-to-needle (D2N), door-to-puncture (D2P), door-to-recanalization (D2R), and puncture-to-recanalization time intervals were compared between the two groups. There were 14 patients (including 8 elderly patients ≥80 years) before and 14 patients (including 10 elderly patients ≥80 years) after the time reduction measure. The mean duration of each of the following time intervals was significantly reduced after the time reduction measure (P < 0.05). To reduce the O2R time, the D2P time is the first time interval that can be reduced. At our center, conferences were regularly held to raise awareness among staff and make specific changes in the workflow, and overall time reduction was achieved. Similar results were obtained in elderly patients.

Prevalence of Patent Foramen Ovale in the Japanese Population- Autopsy Study.

BACKGROUND: Patent foramen ovale (PFO) can cause ischemic stroke because of paradoxical embolism. Autopsy studies have shown that the prevalence of PFO is 25% in whites or blacks. However, there is a paucity of data on the prevalence of PFO in Asians. The aim of this study was to clarify the prevalence of PFO in the Japanese population. METHODS AND RESULTS: We reviewed 52,717 autopsy reports, which were collected and edited by the Japanese Society of Pathology from 2009 to 2012. Next, we inspected consecutive 103 formalin-fixed specimens that had already been examined by certified pathologists from 2009 to 2013 to find PFO and atrial septal aneurysm (ASA). ASA was defined as ≥10 mm protrusion of the septum into the left or the right atrium. In the database of the Japanese Society of Pathology, the incidence of PFO was 0.08% (43/52,717). Inspection of heart specimens disclosed that the prevalence of PFO was 13.6% (14/103). None of the PFO cases was reported at the original autopsy. PFO was more frequently found in the subjects with ASA (50%) than in those without ASA (9.7%) (P=0.004). CONCLUSIONS: PFO is under-reported in autopsy reports. Re-evaluation of heart specimens disclosed that the prevalence of PFO was 13.6%. The prevalence was lower than reported in the past.

Relationship between magnetic resonance angiography-diffusion-weighted imaging mismatch and clinical outcome in endovascular treatment for acute ischemic stroke: subgroup analysis of the Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism--Japan Registry.

BACKGROUND: The presence or absence of the penumbra area is important when performing reperfusion therapy in patients with acute ischemic stroke. As a predictor of this penumbra area, magnetic resonance angiography (MRA)-diffusion-weighted imaging (DWI) mismatch is attracting attention. The usefulness of MRA-DWI mismatch (MDM) using the DWI-Alberta Stroke Program Early Computed Tomography Score (ASPECTS) in endovascular treatment (EVT) of patients with cerebral large vessel occlusion was evaluated. METHODS: Of 1442 patients registered in the Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Registry between July 1, 2010 and June 30, 2011 who presented to the hospital within 24 hours of the onset of acute cerebral infarction because of cerebral large vessel occlusion, 188 patients who had internal carotid artery or middle cerebral artery occlusion and achieved recanalization with EVT were included. Of these, 71 patients underwent intracranial EVT because intravenous recombinant tissue plasminogen activator therapy was ineffective. The associations between the presence or absence of MDM (MDM-positive [MDM-P], DWI-ASPECTS≥6; MDM-negative [MDM-N], DWI-ASPECTS<6) and 90-day prognosis (modified Rankin Scale [mRS]) and symptomatic intracranial hemorrhage (sICH) were examined. RESULTS: Of the 188 patients analyzed, the time from symptom onset to admission was within 3 hours in 143 patients, 3-8 hours in 36 patients, and 8 hours or more in 9 patients. The time from the onset was within 3 hours in 118 patients in the MDM-P and 25 patients in the MDM-N cases. Favorable outcomes (mRS score≤2 at 90 days) were seen in 63 patients (53.4%) in the MDM-P group and 7 patients (28.0%) in the MDM-N group, showing a significantly more favorable clinical outcome in the MDM-P group (P=.027). The incidence of sICH was significantly lower in the MDM-P group (MDM-P group 3.4%, MDM-P group 20.0%; P=.009). The time from the onset was 3-8 hours in 29 patients in the MDM-P group and in 7 patients in the MDM-N group. Favorable outcomes were seen in 12 patients (41.4%) in the MDM-P group and 2 patients (28.6%) in the MDM-N group, with no significant difference between the 2 groups. No patients had sICH. The patients admitted 8 hours or more after the onset were all MDM-P. Five patients (55.6%) had a favorable outcome. CONCLUSIONS: This study demonstrated the safety and efficacy of EVT in MDM-P patients within 3 hours of symptom onset. Although the ratio of patients who had a favorable outcome was high in the MDM-P patients admitted 3-8 hours after the onset, the difference was not significant.

Recurrent transient hemiparesis in a patient with a giant persisting Eustachian valve and patent foramen ovale: atypical hemiplegic migraine or paradoxical cerebral embolism?

We encountered a patient with the overlapping disorders of migraine with aura, migraine-triggered seizures and recurrent transient hemiparesis caused by atypical hemiplegic migraines with motor weakness during headache attacks, but not during the aura period, or paradoxical cerebral embolism. The patient displayed a giant Eustachian valve and patent foramen ovale, through which a spontaneous right-to-left shunt was revealed on transesophageal echocardiography. We considered that the overlapping disorders in the present case were closely related to the spontaneous right-to-left shunt caused by the giant Eustachian valve.

Opalski syndrome caused by vertebral artery compression of the lateral surface of the medulla oblongata.

A 55-year-old man presented with vertigo, nystagmus, and gait ataxia followed by left hemiparesis (Opalski syndrome). T2-weighted magnetic resonance imaging revealed vascular compression of the left lateral side of the medulla oblongata by the left vertebral artery. On diffusion tensor imaging, the level of fractional anisotropy (FA) in the left corticospinal fibers caudal to the pyramidal decussation was lower than that observed in the right corticospinal fibers. Opalski syndrome caused by vascular compression is very rare. This is the first reported case of Opalski syndrome that was imaged on FA.

Additional endovascular therapy in patients with acute ischemic stroke who are nonresponsive to intravenous tissue plasminogen activator: usefulness of magnetic resonance angiography-diffusion mismatch.

BACKGROUND: In patients who are not responsive to intravenous tissue plasminogen activator (IV t-PA), the present study aimed to report recanalization rates, the incidence of hemorrhagic transformation (HT), and clinical outcomes of additional endovascular therapy (AET), and to investigate the usefulness of magnetic resonance angiography-diffusion mismatch (MDM) in a selection of patients eligible for AET. METHODS: Fifty-eight patients who received IV t-PA therapy because of intracranial major artery occlusion between April 2007 and November 2010 were divided into 2 groups: 18 patients in the AET group and 21 patients in the IV t-PA nonresponders group. The remaining 19 patients were responders to IV t-PA and therefore not eligible for this study. Recanalization rates, HT incidence, and 3-month outcomes were assessed, and the relationship between MDM and clinical outcome was examined. RESULTS: A 3-month modified Rankin Scale (mRS) score of 0 to 3 was seen more frequently in the AET group (72% in the AET group v 29% in the nonresponder group; P = .01). Serious outcomes (3-month mRS of 5-6) were seen significantly less often in the AET group (17%) than in the nonresponder group (57%; P = .019). There were no differences in the incidence of HT. In the AET group, reappraisal considering MDM revealed a significantly higher rate of a 3-month mRS of 0 to 3 in the MDM-positive group compared to the MDM-negative group (86% v 25%, respectively; P = .044). Serious outcomes were observed significantly less frequently in the MDM-positive group compared to the MDM-negative group (0% v 75%, respectively; P = .005). CONCLUSIONS: AET for nonresponders to IV t-PA was safe, improved recanalization rates, and led to better prognoses. MDM was a very good predictor of improved prognosis in a selection of eligible patients for AET after IV t-PA.

Clinical review of 28 patients with basilar artery occlusion.

BACKGROUND: We retrospectively analyzed factors related to the outcomes of patients with basilar artery occlusion. METHODS: Twenty-eight patients with basilar artery occlusion admitted to our hospital within 24 hours after onset between April 2007 and December 2010 were included. We investigated parameters related to outcome, such as coexisting disease, clinical type, clinical severity at admission, the site of occlusion and the infarction lesion, the collateral flow from posterior communicating artery, therapy, and time to therapy after onset. RESULTS: Of 28 patients with basilar artery occlusion, good outcomes occurred in 6 patients (21%) and poor outcomes occurred in 22 patients (79%). Clinical severity on admission was significantly different between the 2 groups. Three of 5 patients with percutaneous transluminal angioplasty achieved recanalization. Two of 3 cases with recanalization resulted in poor outcomes. CONCLUSIONS: Clinical severity on admission was the determinant factor of functional prognosis in patients with basilar artery occlusion.

Magnetic resonance angiography-diffusion mismatch reflects diffusion-perfusion mismatch in patients with hyperacute cerebral infarction.

BACKGROUND: We evaluated whether clinical-diffusion mismatch (CDM) or magnetic resonance angiography (MRA)-diffusion mismatch (MDM) is useful in detecting diffusion-perfusion mismatch (DPM) in hyperacute cerebral infarction within 3 hours after stroke onset. METHODS: Among patients with cerebral infarction who arrived within 3 hours after stroke onset at our hospital between May 2007 and December 2010, we included 21 patients (16 men and 5 women; mean age 70 ± 7.8 years) with cerebral infarction of the anterior circulation, and in whom magnetic resonance imaging (diffusion-weighted imaging)/MRA and computed tomograpic perfusion of the head were performed at the time of arrival. DPM-positive status was defined as a difference between DWI abnormal signal area and mean transit time prolongation area (≥ 20% on visual assessment). CDM-positive status was defined as a National Institute of Health Stroke Scale score ≥ 8 and DWI-Alberta Stroke Program Early CT Score (ASPECTS) ≥ 8. MDM-positive status was defined as a major artery lesion and DWI-ASPECTS ≥ 6. RESULTS: Ten of 21 patients had DPM. In all DPM-positive patients, MRA revealed a major artery lesion. Of the 10 DPM-positive patients, 6 were CDM-positive. CDM detected DPM with a sensitivity of 60% and a specificity of 64%. The positive likelihood ratio was 1.65. Of the 10 DPM-positive patients, all were MDM-positive. MDM detected DPM with a sensitivity of 100% and a specificity of 82%. The positive likelihood ratio was 5.5. CONCLUSIONS: In hyperacute cerebral infarction within 3 hours after onset, MDM, as compared with CDM, was able to detect DPM with higher sensitivity and specificity. This suggests that MDM is more reflective of DPM.

Magnetic resonance imaging investigation of secondary degeneration of the mesencephalic substantia nigra after cerebral infarction.

Secondary degeneration of the mesencephalic substantia nigra after cerebral infarction is widely known to occur in animal experiments, but has yet to be sufficiently investigated in human cerebral infarction. This study investigated the background and features of patients exhibiting secondary degeneration of the mesencephalic substantia nigra. The subjects comprised 43 patients admitted to our hospital for cerebral infarction between April 2007 and October 2010 showing secondary degeneration of the mesencephalic substantia nigra on cranial magnetic resonance imaging (MRI). We investigated clinical disease type, location of vascular occlusion, lesion site, and time from onset of symptoms to lesion identification by MRI. The clinical disease type was cardiogenic embolism in 29 patients (67%), atheromatous embolism (artery to artery) in 8 patients (19%), embolism (origin unknown) in 2 patients (5%), infarction after coil embolization for internal carotid aneurysm in 1 patient (2%), arterial dissection in 2 patients (5%), and vasculitis due to Takayasu disease in 1 patient (2%). Magnetic resonance angiography (MRA) identified the occluded vessel as the internal carotid artery in 19 patients (44%), the middle cerebral artery (M1) in 20 patients (47%), and the middle cerebral artery (M2) in 3 patients (7%); MRA was not performed in 1 patient (2%). The cerebral infarctions were striatal in 7 patients (16%) and striatal and cortical in 36 patients (84%). Hyperintense regions in the mesencephalic substantia nigra were observed in all patients after 7-28 days (mean, 13.3 days) on diffusion-weighted imaging or fluid-attenuated inversion recovery and T2-weighted MRI. Most patients with secondary degeneration of the substantia nigra demonstrated clinical disease comprising vascular occlusion of the internal carotid artery or the neighborhood of the middle cerebral artery, which was envisaged to cause a sudden drop in brain circulation across a wide area. Striatal infarctions were observed in all patients. Secondary degeneration of the substantia nigra appeared at 1-4 weeks after onset and disappeared after several months.

Recurring extracranial internal carotid artery vasospasm detected by intravascular ultrasound.

A 24-year-old woman presented with headache and left-sided focal signs following multiple episodes of right monocular visual impairment. Magnetic resonance angiography revealed a decreased vascular image intensity due to a suspicious stenosis in the right internal carotid artery (ICA). The stenosis was not demonstrated on duplex sonography as it was beyond the field of view of the investigation. Intravascular ultrasound (IVUS) revealed that the outer vessel diameter was significantly reduced during stenosis, supporting the presence of vasospasm. Idiopathic recurrent extracranial ICA vasospasm was diagnosed. Recurrent vasospasms of extracranial ICA may be a distinct entity that can cause ischemic stroke.

Patent foramen ovale as a risk factor for cryptogenic brain abscess: case report and review of the literature.

We encountered a patient with brain abscess presumably caused by dental infection. The patient displayed patent foramen ovale (PFO) and a giant Eustachian valve, through which spontaneous right-to-left shunt was revealed by transesophageal echocardiography. Reviewing the literature, we find additional cases where brain abscess originated from an increased amount of flora commonly found in the oral cavity that bypassed the pulmonary vascular bed and the lymphatic system through PFO. Additionally, a Eustachian valve should be considered an adjunctive risk factor for initiating a spontaneous right-to-left shunt and predisposing cryptogenic brain abscess in patients with PFO.

An adult case of pneumocephalus and pneumococcal meningitis associated with the sphenoid sinusitis.

A 60-year-old man was admitted to our hospital after being found at his home in a comatose state. Cerebrospinal fluid and blood cultures were positive for Streptococcus pneumoniae. Brain magnetic resonance imaging (MRI) revealed sinusitis in the sphenoid sinus. Computed tomography demonstrated the presence of multiple air pockets in the basilar cistern, and we diagnosed pneumococcal meningitis complicated with pneumocephalus. Multiple cerebral infarctions were found on brain MRI after admission. In this case, pneumocephalus was secondary to pneumococcal meningitis due to sinusitis on admission, and multiple cerebral infarctions after admission. We demonstrated that early diagnosis is required for the successful treatment of pneumococcal meningitis.

Progressive multiple cranial nerve palsies as the presenting symptom of meningeal carcinomatosis from occult colon adenocarcinoma.

We herein describe a rare case of meningeal carcinomatosis in a 77-year-old woman who had bilateral deafness as the initial symptom of a previously undetected colon cancer malignancy. Meningeal carcinomatosis should be considered in the differential diagnosis in cases of abrupt-onset sensorineural deafness. Both MRI scans and cerebrospinal fluid evaluation are necessary diagnostic tools, and should be used in conjunction as each of these procedures could have false-negative results. This should apply even when there is no known primary malignancy.

Delayed recurrent ischemic stroke after initial good recovery from pneumococcal meningitis.

We describe unusual delayed recurrent episodes of ischemic stroke in a patient with initial good recovery from pneumococcal meningitis due to progressive arterial stenosis for over 3 months. We postulate that any of the following may have been responsible for his condition: widespread cerebral vasculopathy due to the effects of purulent material bathing the base of the brain, an immune-mediated para-infectious condition, or a rebound effect of the primary inflammatory reaction that was initially suppressed by dexamethasone. This case demonstrates that progressive arterial stenosis can evolve months after bacterial meningitis and should be recognized as a potential vascular complication.

Spontaneous cervicocephalic arterial dissection with headache and neck pain as the only symptom.

BACKGROUND AND OBJECTIVE: Cervicocephalic arterial dissection can cause both ischemic stroke and hemorrhagic stroke. However, spontaneous cervicocephalic arterial dissection presenting only with headache and neck pain has rarely been reported. The clinical features of patients with spontaneous cervicocephalic arterial dissection presenting only with headache and neck pain were investigated. METHODS: The subjects were seven patients with spontaneous cervicocephalic arterial dissection with headache and neck pain alone who were admitted to our hospital during the past 3 years. The clinical features of these patients were investigated. The diagnosis of arterial dissection was based on the criteria of the Strategies Against Stroke Study for Young Adults in Japan. RESULTS: The age of the patients (3 males, 4 females) ranged from 35 to 79 (mean, 51.0 ± 16.2) years. Six patients had vertebral artery dissection, one had internal carotid artery dissection, and one had an association of vertebral and internal carotid artery dissection. With the exception of one patient, the headache and neck pain were unilateral. All patients with vertebral artery dissection complained of posterior cervical or occipital pain. In the cases of internal carotid artery dissection, one patient complained of temporal pain, and one patient with co-existing vertebral artery dissection complained of posterior cervical pain. The mode of onset was acute in five patients, thunderclap in one, and gradual and progressive in one. The pain was severe in all cases. Five patients complained of continuous pain, while two had intermittent pain. The quality of the pain was described as throbbing by five patients and constrictive by two. The headache and neck pain persisted for 1 week or longer in six of the seven patients. CONCLUSION: Cervicocephalic arterial dissection should be suspected when patients complain of intense unilateral posterior cervical and occipital pain or temporal pain.

Relationship of obesity to recanalization after hyperacute recombinant tissue-plasminogen activator infusion therapy in patients with middle cerebral artery occlusion.

BACKGROUND: This was a retrospective analysis of factors related to recanalization after hyperacute recombinant tissue-plasminogen activator (rt-PA) infusion therapy in patients with middle cerebral artery occlusion. METHODS: Of the 50 patients (39 males and 11 females; mean age 70 ± 11 years) with cerebral infarction who were able to undergo diffusion-weighted magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA) of the head within 24 hours of starting rt-PA infusion therapy while hospitalized at our center between April 2007 and October 2010, 23 patients (18 males and 5 females; mean age 71 ± 9.4 years) with hyperacute cerebral infarction with findings of obstruction in the proximal segment of the middle cerebral artery (MCA-M1) served as subjects. RESULTS: Of the 23 patients with MCA occlusion, 13 (57%) were recanalized. Analysis of factors related to recanalization revealed a significant difference (P = .019) for obesity (body mass index >25 kg/m(2)), with significantly more obese patients in the nonrecanalized group than in the recanalized group. The study revealed no significant differences in other factors between the 2 groups. CONCLUSIONS: The results suggest that obesity may be involved in recanalization after hyperacute rt-PA infusion therapy in patients with MCA occlusion.

Clinical review of 37 patients with medullary infarction.

BACKGROUND: Clinical features of medullary infarction were compared between patients with lateral medullary infarction and medial medullary infarction METHODS: Thirty-seven patients with medullary infarction (29 with lateral medullary infarction and 8 with medial medullary infarction) who were admitted to our center between April 1, 2007 and March 31, 2010 were examined. Background factors, neurologic signs and symptoms, imaging findings, cause of disease, and outcomes were assessed for patients with lateral and those with medial medullary infarction. RESULTS: Examination of the clinical symptoms and neurologic findings suggested that among patients with medial medullary infarction, few demonstrated all of the symptoms of Dejerine syndrome at onset, and many had lesions that were difficult to locate based only on neurologic findings. Both lateral and medial medullary infarction were frequently caused by atherothrombosis. However, cerebral artery dissection was observed in 31% of patients with lateral medullary infarction and 12.5% of those with medial medullary infarction. In 13% of patients with lateral and 37% of patients with medial medullary infarction, magnetic resonance imaging diffusion-weighted images on the day of onset did not show abnormalities, and the second set of diffusion-weighted images confirmed infarction lesions. For lateral medullary infarction, a more rostral lesion location was correlated with a poorer 90-day outcome. For medial medullary infarction, a more dorsal lesion location was correlated with a poorer 90-day outcome. CONCLUSIONS: The diagnosis rate of medullary infarction using imaging examinations at onset--particularly medial medullary infarction--is not necessarily high. The imaging examinations need to be repeated for patients who are suspected to have medullary infarction based on neurologic signs and symptoms.

Significance of magnetic resonance angiography-diffusion weighted imaging mismatch in hyperacute cerebral infarction.

Therapeutic results with respect to lesion size were analyzed and compared in patients with hyperacute cerebral infarction with and without major artery lesions on magnetic resonance angiography (MRA) and in those who did and did not receive intravenous (IV) tissue plasminogen activator (t-PA). Of the patients with cerebral infarction who visited the hospital within 3 hours of onset between April 2007 and September 2009, 127 patients with cerebral infarction in the anterior circulation region in whom head magnetic resonance imaging (diffusion-weighted imaging [DWI]) or MRA was performed (81 men and 46 women; mean age, 71 ± 11 years) were enrolled. Major artery lesions (+) were defined as internal carotid artery occlusion and middle cerebral artery (M1/M2 segment) occlusion and ≥50% stenosis. Based on the presence or absence of major artery lesions and the size of DWI lesions, the subjects were divided into 3 groups: MRA-DWI mismatch (+) group [major artery lesion (+) and DWI-ASPECTS ≥6], MRA-DWI mismatch (-) group [major artery lesion (+) and DWI-ASPECTS <6], and major artery lesion (-) group. IV t-PA was given to 21 of the 64 patients in the MRA-DWI mismatch (+) group, to 1 of the 24 patients in the MRA-DWI mismatch (-) group, and to 9 of the 39 patients in the major artery lesion (-) group. In the MRA-DWI mismatch (+) group (n = 64), the median National Institutes of Health Stroke Scale (NIHSS) score on admission was higher in t-PA-treated patients than in t-PA-untreated patients (15 vs 11). The modified Rankin scale (mRS) score at day 90 after onset was more favorable in t-PA-treated patients (0-2 in 10 patients [48%] and 3-6 in 11 patients [52%]) than in t-PA-untreated patients (0-2 in 12 patients [28%] and 3-6 in 31 patients [72%]). After adjusting for admission NIHSS score, there was a significant difference in outcome (mRS score) between t-PA-treated patients (0-2 in 10 patients [48%] and 3-6 in 11 patients [52%]) and t-PA-untreated patients (0-2 in 3 patients [9%] and 3-6 in 29 patients [91%]) (P = .002). In the MRA-DWI mismatch (-) group (n = 24), mRS scores at day 90 after onset were poor in both t-PA-treated (3-6 in 1 patient [100%]) and t-PA-untreated patients (0-2 in 1 patient [4%] and 3-6 in 22 patients [96%]). In the major artery lesion (-) group (n = 39), mRS scores at day 90 after onset were favorable in both t-PA-treated (0-2 in 9 patients [100%]) and t-PA-untreated patients (0-2 in 28 patients [93%] and 3-6 in 2 patients [7%]). When comparing major artery lesions in the MRA-DWI mismatch (+) group, outcomes were more favorable in patients with M1/M2 segment lesions who received t-PA than in those who did not receive t-PA. In the MRA-DWI mismatch (+) group, the prognosis was significantly better for t-PA-treated patients than for t-PA-untreated patients, suggesting that IV t-PA is indicated in patients with MRA-DWI mismatch.