Left Middle Cerebral Artery Stenosis Research Articles

Synthesizing 4D Magnetic Resonance Angiography From 3D Time-of-Flight Using Deep Learning: A Feasibility Study.

Objective and background This study aimed to develop a deep convolutional neural network (DCNN) model capable of generating synthetic 4D magnetic resonance angiography (MRA) from 3D time-of-flight (TOF) images, allowing estimation of temporal changes in arterial flow. TOF MRA provides static information about arterial structures through maximum intensity projection (MIP) processing, but it does not capture the dynamic information of contrast agent circulation, which is lost during MIP processing. Considering the principles of TOF, it is hypothesized that dynamic information about arterial blood flow is latent within TOF signals. Although arterial spin labeling (ASL) can extract dynamic arterial information, ASL MRA has drawbacks, such as longer imaging times and lower spatial resolution than TOF MRA. This study's primary aim is to extend the utility of TOF MRA by training a machine-learning model on paired TOF and ASL data to extract latent dynamic information from TOF signals. Methods A DCNN combining a modified U-Net and a long-short-term memory (LSTM) network was trained on a dataset of 13 subjects (11 menand two women, aged 42-77 years) using paired 3D TOF MRA and 4D ASL MRA images. Subjects had no history of cerebral vessel occlusion or significant stenosis. The dataset was acquired using a 3T MRI system with a 32-channel head coil. Preprocessing involved resampling and intensity normalization of TOF and ASL images, followed by data augmentation and arterial mask generation. The model learned to extract flow information from TOF images and generate 8-phase 4D MRA images. The precision of flow estimation was evaluated using the coefficient of determination (R²) and Bland-Altman analysis. A board-certified neuroradiologist validated the quality of the images and the absence of significant stenosis in the major cerebral arteries. Results The generated 4D MRA images closely resembled the ground-truth ASL MRA data, with R² values of 0.92, 0.85, and 0.84 for the internal carotid artery (ICA), proximal middle cerebral artery (MCA), and distal MCA, respectively. Bland-Altman analysis revealed a systematic error of -0.06, with 95% agreement limits ranging from -0.18 to 0.12. Additionally, the model successfully identified flow abnormalities in a subject with left MCA stenosis, displaying a delayed peak and subsequent flattening distal to the stenosis, indicative of reduced blood flow. Visualization of the predicted arterial flow overlaid on the original TOF MRA images highlighted the spatial progression and dynamics of the flow. Conclusions The DCNN model effectively generated synthetic 4D MRA images from TOF images, demonstrating its potential to estimate temporal changes in arterial flow accurately. This non-invasive technique offers a promising alternative to conventional methods for visualizing and evaluating healthy and pathological flow dynamics. It has significant potential to improve the diagnosis and treatment of cerebrovascular diseases by providing detailed temporal flow information without the need for contrast agents or invasive procedures. The practical implementation of this model could enable the extraction of dynamic cerebral blood flow information from routine brain MRI examinations, contributing to the early diagnosis and management of cerebrovascular disorders.

Transradial intra-aortic catheter looping in the angioplasty of severe intracranial symptomatic arteriosclerotic diseases.

This study aims to investigate the effect and feasibility of intra-aortic catheter looping via transradial access in angioplasty for symptomatic intracranial severe (>70%) atherosclerotic stenosis or occlusion of large arteries (SISOLAs). Patients with SISOLAs who underwent transradial endovascular angioplasty using the catheter looping technique in the ascending aorta were retrospectively enrolled. The clinical data and treatment outcomes were analyzed. Fifteen patients aged 48-71 years were enrolled in this study. Left vertebrobasilar artery occlusion was present in 1 (6.7%) patient, severe left middle cerebral artery stenosis in 7 (46.7%) patients, severe left internal carotid artery (ICA) stenosis of the ophthalmic segment in 4 (26.7%) patients, severe left ICA stenosis of the cavernous segment in 2 (13.3%) patients, and severe right middle cerebral artery stenosis in 2 (13.3%) patients. The arterial stenosis ranged from 70 to 92% (mean 86%) before stenting. The looping of a guiding catheter in the ascending aorta via transradial access for angioplasty was successful in all patients (100%). The vertebral artery intracranial segment occlusion was successfully recanalized, while severe stenosis in the remaining 14 patients was successfully eliminated. After endovascular recanalization, the residual stenosis was reduced by 12-26% (median 18%). No puncture-related complications or surgical-related neurological complications occurred in these patients. In the follow-up angiography conducted on 10 (66.7%) patients after 6-25 months, no in-stent restenosis was detected. Intra-aortic guiding catheter looping via transradial access for endovascular angioplasty of SISOLAs is technically safe, feasible, and effective, especially when the transfemoral artery approach is difficult or impossible to undertake.

Ophthalmic artery flow direction change predicts recurrence of ischemic stroke after carotid stenting: a longitudinal observational study

Background and purposeThe implantation of carotid artery stents prevents recurrent ischemic stroke in patients with carotid stenosis. This study aimed to investigate associations between change of ophthalmic artery flow (COAF) post carotid stenting and recurrent ischemic stroke, as well as the link toward the anterior and posterior circulations and patients’ prognosis after carotid stenting.MethodsThis retrospective, longitudinal cohort study recruited 87 left side carotid stenosed ischemic stroke patients undergoing left side carotid stenting between year of 2009 and 2013, and patients were followed up to 9 years after carotid procedures. Clinical data were derived from medical records. The primary outcome was stroke recurrence. Predictive factors were stenosis > 50% in one intracranial artery and ROAF. Kaplan–Meier and Cox regression analyses were used to identify risk factors associated with stroke recurrence.ResultsAmong 87 included patients undergone left side carotid stent treatment, 44 had stroke recurrence within 3 years after carotid stenting. The recurrence group had significantly greater proportions of COAF after stenting (p = 0.001), and middle cerebral artery (MCA) and basilar artery or vertebral artery (BA/VA) stenosis > 50% (all p < 0.001) than the no-recurrence group. Survival was significantly shorter in patients with COAF than in those without (p < 0.01). Regression analysis showed that COAF was associated with stroke recurrence (HR: 3.638, 95% CI 1.54–8.62, p = 0.003). The recurrence rate was highest in patients with bilateral MCA stenosis > 50% (100%), followed by left MCA stenosis > 50% plus BA/VA stenosis > 50% (83.33%) or COAF (82.14%). Patients with bilateral MCA stenosis < 50% had no recurrence within 3-year follow-up.ConclusionsPrognosis after carotid stenting is poorer for patients with MCA stenosis > 50%, BA/VA stenosis > 50% and/or COAF. Carotid duplex and magnetic resonance angiography provide definitive information for prognosis prediction.

Depression In Patients Undergoing Coronary Artery Bypass Graft (CABG) Surgery is Associated with Worse Cognition and Left Middle Cerebral Artery Stenosis

Depression In Patients Undergoing Coronary Artery Bypass Graft (CABG) Surgery is Associated with Worse Cognition and Left Middle Cerebral Artery Stenosis

Abstract 1122‐000021: Delayed Vasospasm and Cerebral Ischemia Following Mild Traumatic Brain Injury

Introduction : Post‐traumatic vasospasm (PTV) is a significant cause of morbidity and mortality following traumatic brain injury (TBI). 1 Delayed PTV is thought to occur due to inflammation from SAH. 1 The risk of symptomatic PTV is associated with the severity of TBI. 1,2,3 Treatment of PTV traditionally involves agents used in aneurysmal vasospasm such as Nimodipine. Intra‐arterial and intravenous verapamil and milrinone have been utilized to treat PTV. 4 We present a rare case of delayed cerebral ischemia caused by PTV without SAH treated with intra‐arterial milrinone and oral verapamil. Methods : This is a case report of a case of a 16‐day delay of cerebral ischemia secondary to PTV. Results : A 19‐year‐old female without significant medical history presented to the emergency room as the restrained driver in a motor vehicle collision involving a car versus a tree. The patient’s Glasgow Coma Scale score was 13 and the initial head CT did not demonstrate SAH with a Rotterdam score of 0. There were multiple fractures and soft tissue contusions noted on imaging which required surgical correction and splinting. The patient’s hospital stay was complicated by a large retroperitoneal hematoma requiring blood transfusions and surgical evacuation. 16 days after admission, the patient experienced sudden‐onset right upper extremity paralysis and weakness of the right leg. CT head demonstrated loss of gray‐white differentiation in the left middle cerebral artery (MCA) territory and CT angiography demonstrated 70% stenosis of the left supra‐clinoid internal carotid artery (ICA) and proximal left MCA. Cerebral angiography demonstrated 60% stenosis left supra‐clinoid ICA and 60% stenosis at the origin of the left MCA consistent with PTV. Left MCA stenosis improved to 20% post 10 mg intra‐arterial milrinone in the left ICA (Figure 1). The patient also received verapamil orally. Transcranial doppler demonstrated elevated peak systolic velocities at 298 cm/s in the left MCA and 276 cm/s in the left ICA. Six days later this improved to 150 cm/s in the left MCA and 151 cm/s in the left ICA. The patient continued to be unable to move her right side against gravity with dense expressive aphasia and dysarthria at discharge to inpatient rehabilitation. At follow‐up 4 weeks later, her right hemiparesis had improved significantly to being able to stand with assistance and her expressive aphasia had improved from one word to occasionally forming several word sentences. Conclusions : PTV is a potentially devastating complication of TBI. As our case demonstrates, the presence of mild TBI and absence of SAH may be falsely reassuring. 2 Additionally, our case report demonstrates that intra‐arterial milrinone causes radiographic improvement in PTV. Further studies are needed for the best screening and diagnostic exams for PTV and therapeutic interventions.

Abstract P575: Impaired Distal Perfusion Predicts In-Hospital Outcome in Patients With Symptomatic Middle Cerebral Artery Stenosis

Background: Perfusion imaging is increasingly used to risk stratify patients with symptomatic intracranial stenosis. Length of hospital stay (LOS) in patients with ischemic stroke is a surrogate marker of increased morbidity. We aim to determine the association between perfusion delay on T max (&lt; 4 sec, 4-6 sec, and &gt; 6 sec) on perfusion weighted imaging and LOS in patients with symptomatic middle cerebral artery (MCA) stenosis. Methods: We included consecutive patients with left MCA stenosis admitted with ischemic stroke or TIA &lt;7 days from onset who underwent perfusion imaging (CT or MR perfusion) processed with RAPID software. We excluded patients with core infarct ≥ 30 mL. Perfusion mismatch was divided into three groups: mismatch volume ≥ 15 mL based on T max &gt; 6 sec delay, mismatch volume ≥ 15 mL based on T max 4-6 sec delay, and neither of the above mismatch patterns. The primary outcome was LOS, both as a continuous variable and categorical (≥ 7 days (prolonged LOS) vs. &lt;7 days). Results: 179 out of 194 patients met the inclusion criteria; mean age was 70.2 ± 15.4 years, 53.1% were women, median (IQR) NIHSS was 4 (1-9); 83.2% underwent MR perfusion; 38.5% had a mismatch volume ≥ 15 mL based on T max &gt; 6 sec and 31.3% had a mismatch volume ≥ 15 mL based on T max 4-6 sec and the median (IQR) LOS was 4 days (2-8). After adjusting for age and NIHSS, T max &gt; 6 sec mismatch definition was associated with prolonged LOS (OR 2.90 95% CI 1.06-8.18; p=0.039) but T max 4-6 sec definition was not (OR 1.45 95% CI 0.46-4.58, p=0.528), without any interaction based on perfusion imaging modality (p interaction = 0.568). We found similar associations when LOS was considered as a continuous variable for T max &gt; 6 sec (β coefficient=2.01, 95% CI 0.05-3.97, p=0.044) and T max 4-6 sec (β coefficient=1.24, 95% CI -0.85-3.34, p=0.244). In receiver operating curves, the optimal mismatch volume for T max &gt; 6 sec was 10 mL (sensitivity 0.61 and specificity 0.63) whereas for T max 4-6 sec it was 39 mL (sensitivity 0.61 specificity 0.56). Conclusion: In patients with recently symptomatic MCA stenosis, the T max &gt; 6 sec definition for mismatch, but not T max 4-6 sec, is associated with prolonged LOS. Prospective studies are needed to validate our findings and define the optimal mismatch threshold in patients with symptomatic MCA stenosis.

Dilated cardiomyopathy-related stroke mimicking large-artery atherosclerosis-related stroke: report of two cases

The clinical characteristics and treatment of stroke caused by dilated cardiomyopathy (DCM) are not clear, especially in patients with large-artery atherosclerosis (LAA)-related stenosis, which commonly causes acute ischemic stroke (AIS); therefore, the diagnosis and treatment of such patients are challenging. Herein, we summarize the clinical characteristics and suggest clues to guide the diagnosis and treatment of two cases. Case 1: A 67-year-old woman with a history of DCM presented with sudden-onset slurred speech and left limb weakness (&gt;2 hours duration), which worsened after intravenous thrombolysis. Repeated brain computed tomography showed no hemorrhage; thus, cerebral artery occlusion or embolism was suspected. Emergency magnetic resonance imaging (MRI) and angiography (MRA) revealed acute multiple bilateral cerebral infarctions and severe left middle cerebral artery stenosis, respectively. We considered a DCM-related stroke and administered anticoagulation therapy. Subsequently, the patient’s symptoms improved significantly, and she was discharged on day 9, after showing no abnormal neurological signs. Case 2: A 49-year-old man with a history of DCM presented with acute headache and blurred vision for 4 days. MRI and MRA revealed multiple acute cerebral infarctions and left vertebral artery stenosis, respectively. We considered an LAA-related stroke and administered antiplatelet and cholesterol-lowering drugs. Eventually, the patient was discharged on day 13, after his right-sided hemianopia improved significantly. Both patients had LAA, which can be easily misdiagnosed as a stroke. LAA-related and DCM-related stroke need to be differentiated. DCM-related AIS lesions are often distributed in the areas supplied by the different cerebral arteries. It is necessary to carefully analyze the shape, location, and scope of the lesions, and identify the main causes of stroke. Anticoagulant therapy is preferred for DCM-related AIS.

Association of Cerebral Artery Stenosis With Post-stroke Depression at Discharge and 3 Months After Ischemic Stroke Onset.

Background: Post-stroke depression (PSD) is one of the most common complications after stroke, which seriously affects patients' recovery outcome. Although vascular depression has been extensively studied, the relationship between cerebral artery stenosis and PSD has not been clarified so far.Methods: Two hundred ninety-eight patients with ischemic stroke (72 women, 226 men) with computed tomography angiography (CTA) or magnetic resonance angiography (MRA) were included in this study. Cerebral artery stenosis ≥50% was used as the cut-off value. The DSM-V diagnostic criteria of PSD was met and the 17-item Hamilton Rating Scale for Depression (HAMD-17) score over 7 at discharge and 3 months after stroke onset was regarded as the primary outcome. The χ2-test, Mann-Whitney U-test, and t-test were used to check for statistical significance.Results: At discharge, Barthel index (p < 0.001), left middle cerebral artery stenosis (p = 0.019), drinking history (p = 0.048), basilar artery stenosis (p = 0.037) were significantly associated with PSD. At 3 months after ischemic stroke onset, Barthel index (p = 0.011), left middle cerebral artery stenosis (p = 0.012), female gender (p = 0.001) were significantly associated with PSD.Conclusions: The findings demonstrated that left middle cerebral artery and basilar artery stenosis are associated with PSD. It was suggested that cerebral artery stenosis was a risk factor of PSD and should be recognized and intervened early.Registration Number: ChiCTR-ROC-17013993.

Hemodynamic ischemia of the anterior choroidal artery and reversal by carotid artery stenting 10 years after ipsilateral superficial temporal artery-middle cerebral artery bypass for symptomatic left middle cerebral artery stenosis.

The pathogenesis of anterior choroidal artery (AChA) territory infarction includes various mechanisms, but hemodynamic causes are rare and difficult to diagnose. 77- year-old man, who had moderate left ICA stenosis and he had treated with STA-MCA bypass surgery for severe symptomatic left MCA stenosis 10 years earlier, was admitted with right hemiparesis and confused state. On admission, magnetic resonance imaging and angiography demonstrated patent bypass, but severe stenosis of left ICA with no opacification of the left AChA and A1 portion of the left ACA. Diffusionweighted imaging demonstrated ischemic lesion in the left corona radiata. Together with clinical findings, hemodynamic ischemia of the AChA region was suspected and left carotid artery stenting resulted in prompt improvement of symptoms. Hemodynamic ischemia of the AChA territory is rare, however, should be considered as a potential target of treatment when the ipsilateral ICA, A1 and M1 show stenoocclusive lesions.

A Case of Recurrent Stroke in Left MCA Stenosis

We report the clinical, neuro-radiological findings of a young man who was admitted to Apollo Hospitals Dhaka, Bangladesh because of abrupt onset of aphasia and right sided mild hemiparesis. He had two strokes six days apart one and half years ago. His past medical history was significant for HTN, smoking. His MRI of the Brain showed acute infarct in left middle cerebral artery (MCA) region congruent with his symptoms and signs. MRA done during his first stroke showed left MCA long segment luminal narrowing. DSA done during initial stroke showed complete occlusion of superior division of left MCA with collateral flow from left anterior cerebral artery (ACA) and posterior cerebral artery (PCA) to left MCA. Other extensive work up for stroke etiology was inconclusive. His stroke recurrence points towards left MCA stenosis (which is reversible) with good collateral circulation which helped the patient get significant neurological recovery. In young patients with recurrent strokes with or without conventional risk factors, vascular anomalies (intra-cranial and extra-cranial) should be investigated to find out the other rare causes for strokes. As TEE was not done here, it conclusively can not be ascertained that some cardio-embolic source of stroke was not present. DOI: http://dx.doi.org/10.3329/pulse.v6i1-2.20359 Pulse Vol.6 January-December 2013 p.70-74

E-010 Prolonged Neurologic Deterioration Following Acetazolamide Testing in the Acute Phase Following Ischaemic Stroke

BackgroundAcetazolamide induces cerebral vasodilatation and may be used to measure cerebrovascular reserve in patients with cerebral arteriopathy. While acetazolamide is known to induce transient neurologic deficits as a result of...

Recurrent inflammatory stenosis of the M1 segment: diagnostic and therapeutic considerations

Dear Sir: Recent advances of imaging technology have helped to identify stenoses of intracranial arteries as an important cause of cerebral ischemia [1]. It has been estimated that up to 10% of strokes are caused by intracranial occlusive disease. The introduction of intracranial angioplasty and stenting has added a new therapeutic option [2]. However the management of patients with a progressive middle cerebral artery stenosis can remain difficult even with a combination of medical and interventional treatment. A 60-year-old female patient of Indian origin presented in August 2008 with subarachnoid haemorrhage centred on the right Sylvian fissure. CT angiography revealed a tight stenosis of the proximal right middle cerebral artery (M1segment) as the sole abnormality. Subsequent intra-arterial DSA confirmed the presence of the stenosis and also showed distended lenticulostriate arteries on the right and an expansion in the extent of brain tissue supplied from the left ICA at the expense of the right MCA territory. The rupture of one of the friable collateral blood vessels was presumed to be the cause for the subarachnoid haemorrhage, rendering the stenosis symptomatic. As the patient had a history of coronary artery disease and hypercholesterolaemia, the stenosis was initially considered to be due to atherosclerosis. However, the patient subsequently developed transient episodes of left arm weakness and possible jaw claudication. MRI brain did not show any ischaemic lesions, but MRA showed new stenoses affecting the proximal left MCA and distal right internal carotid artery. Contrast-enhanced MRI demonstrated contrast enhancement in the wall of the right MCA. The combination of vessel wall enhancement and newly developed stenoses suggested cerebral vasculitis. Extensive investigation for a systemic vasculitis and CSF tests failed to show any abnormalities. Based on the imaging appearances and the patient’s recurrent symptoms, she was treated with steroids and cyclophosphamide, while her treatment for atheromatous disease was continued. The patient’s symptoms persisted after an initial course of high dose steroids, and a repeat MRA showed worsening of the MCA stenosis. Therefore an angioplasty of the M1 stenosis was performed under general anaesthesia 3 months (end of October 2008) after initial admission (Fig. 1a, b). The balloon (Gateway 2×8 mm) was inflated three times resulting in a significant improvement of the right hemispheric perfusion. There were no procedural complications, either clinically or on DWI MRI. After immunosuppressive treatment with cyclophosphamide for 6 months, a contrast-enhanced MRI showed improvement, though not a complete resolution of the vessel wall enhancement (Fig. 1c). The left middle cerebral artery stenosis had resolved. This improvement was regarded as supporting the presumed diagnosis of vasculitis with response to treatment. W. Kuker (*) : J. Downer Department of Neuroradiology, West Wing John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK e-mail: wilhelm.kuker@clneuro.ox.ac.uk

Resolution of cerebral artery stenosis in a child with sickle cell anemia treated with hydroxyurea

Stroke is a major cause of morbidity and mortality in individuals with sickle cell anemia (SCA) [1]. Transcranial Doppler (TCD) ultrasound can identify patients at increased risk of stroke [2,3], and chronic transfusion therapy decreases stroke risk by 92% in the highest risk group, defined by abnormal [time average mean of the maximum velocity (TAMV) > 200 cm/sec] TCD flow velocities [4]. However, chronic transfusions can lead to serious complications, and the optimal management strategy for patients with cerebral artery stenosis whose TCD flow velocities are conditional (TAMV = 170-199 cm/sec) is unknown. Hydroxyurea effectively prevents several complications of SCA [5], but there are no controlled studies demonstrating its effectiveness in cerebral artery stenosis or primary stroke prevention in SCA. We report the case of a 4-year-old child with SCA found to have left middle cerebral artery stenosis on evaluation for unilateral conditional TCD flow velocities. Hydroxyurea therapy was followed by normalization of TCD flow velocities and resolution of vascular stenosis. This case adds to the literature suggesting that hydroxyurea can successfully reverse cerebral artery stenosis in patients with SCA, further supporting the need for controlled clinical trials of hydroxyurea for cerebral vasculopathy and primary stroke prevention in SCA.

Simultaneous Occurrence and Interaction of Hypoperfusion and Embolism in a Patient With Severe Middle Cerebral Artery Stenosis

The coincidence of hemodynamic and embolic findings in patients with stroke from large artery stenosis has suggested an interaction of both pathologies. This has emerged into the hypothesis of an impaired washout of emboli in the presence of hypoperfusion. We propose an additional link between both pathologies. A 48-year-old woman presented with a recurrent symptomatic severe left middle cerebral artery stenosis. MRI depicted left hemispheric ischemic infarcts in the deep and subcortical white matter and in the cortical border zone. One-hour transcranial Doppler monitoring detected 64 microembolic signals distal to the arterial stenosis. Monitoring also revealed recurrent thrombus formation at the stenotic plaque with decline of poststenotic flow velocity followed by embolism with abrupt excessive flow velocity increase and subsequent normalization at the initial baseline level. Cerebrovascular reserve in the distribution territory of the stenosed artery as assessed by transcranial Doppler after carbon dioxide stimulation revealed a normal reserve capacity in periods with baseline poststenotic flow velocity and an exhausted reserve capacity when flow velocity was decreased due to stenotic thrombus formation. In our patient, adherent thrombus formation resulted in an increasing severity of the stenosis with subsequent vasodilatation and diminution of flow resistance in the depending vascular distribution territory. MRI suggested that adherent thrombi were predominantly washed into terminal supply and border zone brain regions, ie, into regions with supposed maximum vasodilatation and least flow resistance immediately before thrombus avulsion. Preferred wash-in of emboli into regions with low blood flow resistance might be an additional mechanism besides impaired washout in patients with severe large artery disease.

Probabilistic Anatomic Mapping of Cerebral Blood Flow Distribution of the Middle Cerebral Artery

Probabilistic atlases are more representative of the population than single brain atlases. They allow anatomic and functional labeling of the results of group studies in stereotactic space and, hence, the automated anatomic labeling of individual brain imaging data. In the current study, probabilistic maps of the blood flow distribution of the middle cerebral artery (MCA) were developed using the basal and MCA brain SPECT images. Twenty-nine patients (mean age +/- SD, 54.6 +/- 6.1 y) who previously received placement of a stent for MCA stenosis (right MCA stenosis, 15 patients; left MCA stenosis, 14 patients) were included in the current study. Of the 29 MCA SPECT images, 18 were analyzed for the final result because 11 MCA SPECT images revealed an uneven uptake distribution of (99m)Tc-ethylcysteinate dimer in the brain. MCA brain SPECT images were coregistered to basal brain SPECT images, and spatial normalization parameters used for basal brain SPECT images were reapplied to MCA brain SPECT for anatomic standardization. Pixel counts of the MCA brain SPECT images were then normalized, and the probabilistic map of cerebral perfusion distribution (perfusion probabilistic map) for each hemisphere was determined by averaging the spatial- and count-normalized MCA brain SPECT images. Population-based probabilistic maps representing the extent of MCA territory (extent probabilistic map) were also composed by averaging the binary images obtained by thresholding the spatially normalized MCA brain SPECT images. The blood supply from the MCA to the basal ganglia area was largest (probability, 0.6 approximately 0.8), followed by the insular cortex (probability, 0.3 approximately 0.5), and various cerebral cortical areas (probability, 0.2 approximately 0.4). The MCA reached to deep structures of the brain, including the internal capsule, caudate nucleus, putamen, globus pallidus, insular cortex, and thalamus with a high-extent probability. A population-based probabilistic map of MCA flow distribution was generated by using MCA brain SPECT images. This map could be a potential tool for the analysis of major cerebral artery distribution, especially the MCA. Furthermore, the probabilistic MCA atlas could be used to define the object delineation of the MCA territory, to quantify ischemic disease affecting the MCA, to predict prognosis, and to risk stratification of cerebrovascular diseases, especially affecting the MCA.

Stevens-Johnson Syndrome Associated With Intravenous Acetazolamide Administration for Evaluation of Cerebrovascular Reactivity-Case Report-

A 62-year-old man with left middle cerebral artery stenosis manifesting as transient ischemic attack underwent evaluation of regional cerebrovascular reactivity to acetazolamide using single photon emission computed tomography. Three days after intravenous administration of acetazolamide, erythematous eruptions of various sizes appeared on his back and spread over almost his entire body. Subsequently, painful ulcerations developed on his lips, and oral and nasal mucosa, and the conjunctiva became hyperemic, indicating Stevens-Johnson syndrome. The results of the lymphocyte transformation test were positive to only acetazolamide. Stevens-Johnson syndrome, also known as erythema multiforme major, can be life-threatening, and may be induced by intravenous administration of acetazolamide.

EDAS Procedure for Sickle Cell Anemia with Stroke: Report of Four Cases.

Children with sickle cell anemia (SCA) and stroke receive chronic transfusions to prevent a recurrent stroke. Despite transfusions, 10–20% have a recurrent stroke and 43% develop moyamoya changes. One treatment option for moyamoya changes is encephaloduroarteriosynangiosis (EDAS) procedure. We report four children with SCA and stroke who have undergone EDAS procedure for progressive clinical and/or imaging findings.Case 1. Five -year-old female with SCA presented with left sided weakness. MRI showed acute infract in the right frontal and parietal areas. She was treated with chronic transfusions. Two years later MRI/MRA showed stenosis in bilateral supraclinoid internal carotid arteries (ICA) and bilateral M1 segments. Patient underwent bilateral EDAS procedures 6 months apart. She tolerated both procedures well and is clinically stable 6 months post second surgery.Case 2. 5-year-old female with SCA presented with right-sided weakness. MRI showed acute infarct in the left middle cerebral artery (MCA) distribution. She was treated with monthly transfusions. Twenty-two months after the initial stroke she presented with left sided weakness. MRI/MRA showed an acute infarct in the right frontal lobe with significant stenosis in bilateral ICA's, and left MCA. She was started on Hydroxyurea in addition to transfusions. She underwent EDAS on the right side. Patient tolerated procedure well. She is one year post surgery and is clinically stable. MRI done 10 months post surgery showed no new infarcts.Case 3. Four year old male with SCA presented with right facial palsy and right-sided weakness. MRI/MRA showed an infarct in the left frontal area and left MCA stenosis. He developed multiple alloantibodies after the initial partial exchange transfusion and was started on Hydroxyurea. His HbF increased to 20%. Repeat MRI/MRA 3 years after the initial stroke showed occlusion of the left MCA and prominent transganglionic collaterals. He underwent EDAS procedure on the left side. Five years after the initial stroke patient had a repeat MRI/MRA that showed occlusion of bilateral posterior cerebral arteries. He was still on Hydroxyurea with HbF level at 35%. He underwent EDAS procedure on the right side. He is clinically doing well one month after the second procedure.Case 4. Five-year-old male with HbSS disease presented with seizures and right-sided weakness. An MRI showed right parietal infarct, and occlusion of the supraclinoid ICA's bilaterally. He was treated with monthly transfusions. Despite being compliant with transfusion therapy, he had a repeat stroke 26 months after the initial stroke. MRI revealed marked stenosis of the bilateral ICA's, middle and anterior cerebral arteries. Patient underwent a left sided EDAS procedure. He is on chronic transfusions along with Hydroxyurea. He is clinically stable 6 months post surgery. In summary, we report 4 cases of sickle cell anemia with stroke, who have undergone EDAS procedure. All patients tolerated the procedure well. However, the effect of this procedure on long-term neuropsychological outcome remains to be seen.Clinical characteristics of sickle cell patients undergoing EDAS procedure for strokePatient numberAge at strokeTreatment for strokeRepeat strokeMoya moya changesAge at EDASTreatment after EDASTime elapsed since EDAS (months)15TxNoYes8 (R), 8 (L)Tx12 (R), 6 (L)25TxYesYes8Tx, HU1234HUNoYes7 (L), 9 (R)Tx25 (L), 1 (R)45TxYesYes8Tx, HU6EDAS: encephaloduroarteriosynangiosis, Tx: treatment, HU: Hydroxyurea, R:right, L: left

Transcranial Doppler Detection of Microemboli in a Stroke Patient with Polycythemia rubra vera

We report a case of a 63-year-old man without known risk factors for cerebrovascular disease who developed a right hemiparesis with slow onset and subsequent clinical improvement. Cerebral computed tomography and magnetic resonance showed two left hemispheric infarctions with hemorrhagic transformation. Transcranial Doppler examination showed a left middle cerebral artery stenosis and frequent high-intensity transient signals (HITS) only on the left side. Hematological tests revealed polycythemia rubra vera. Clinical improvement was associated with a reduction in the number of HITS on transcranial Doppler and a reduction in hematocrit levels. To our knowledge, this is the first report of HITS on transcranial Doppler in a stroke patient with polycythemia rubra vera