Chitra Venkatasubramanian
Stanford University
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Featured researches published by Chitra Venkatasubramanian.
Stroke | 2011
Chitra Venkatasubramanian; Michael Mlynash; Anna Finley-Caulfield; Irina Eyngorn; Rajalakshmi Kalimuthu; Ryan W Snider; Christine A.C. Wijman
Background and Purpose— Knowledge on the natural history and clinical impact of perihematomal edema (PHE) associated with intracerebral hemorrhage is limited. We aimed to define the time course, predictors, and clinical significance of PHE measured by serial magnetic resonance imaging. Methods— Patients with primary supratentorial intracerebral hemorrhage ≥5 cm3 underwent serial MRIs at prespecified intervals during the first month. Hematoma (Hv) and PHE (Ev) volumes were measured on fluid-attenuated inversion recovery images. Relative PHE was defined as Ev/Hv. Neurologic assessments were performed at admission and with each MRI. Barthel Index, modified Rankin scale, and extended Glasgow Outcome scale scores were assigned at 3 months. Results— Twenty-seven patients with 88 MRIs were prospectively included. Median Hv and Ev on the first MRI were 39 and 46 cm3, respectively. Median peak absolute Ev was 88 cm3. Larger hematomas produced a larger absolute Ev (r2=0.6) and a smaller relative PHE (r2=0.7). Edema volume growth was fastest in the first 2 days but continued until 12±3 days. In multivariate analysis, a higher admission hematocrit was associated with a greater delay in peak PHE (P=0.06). Higher admission partial thromboplastin time was associated with higher peak rPHE (P=0.02). Edema volume growth was correlated with a decline in neurologic status at 48 hours (81 vs 43 cm3, P=0.03) but not with 3-month functional outcome. Conclusions— PHE volume measured by MRI increases most rapidly in the first 2 days after symptom onset and peaks toward the end of the second week. The timing and magnitude of PHE volume are associated with hematologic factors. Its clinical significance deserves further study.
Stroke | 2010
Jean-Marc Olivot; Michael Mlynash; Jonathan T. Kleinman; Matus Straka; Chitra Venkatasubramanian; Roland Bammer; Michael E. Moseley; Gregory W. Albers; Christine A.C. Wijman
Background and Purpose— The pathophysiology of the presumed perihematomal edema immediately surrounding an acute intracerebral hemorrhage is poorly understood, and its composition may influence clinical outcome. Method— Twenty-three patients from the Diagnostic Accuracy of MRI in Spontaneous intracerebral Hemorrhage (DASH) study were prospectively enrolled and studied with MRI. Perfusion-weighted imaging, diffusion-weighted imaging, and fluid-attenuated inversion recovery sequences were coregistered. TMax (the time when the residue function reaches its maximum) and apparent diffusion coefficient values in the presumed perihematomal edema regions of interest were compared with contralateral mirror and remote ipsilateral hemispheric regions of interest. Results— Compared with mirror and ipsilateral hemispheric regions of interest, TMax (the time when the residue function reaches its maximum) and apparent diffusion coefficient were consistently increased in the presumed perihematomal edema. Two thirds of the patients also exhibited patchy regions of restricted diffusion in the presumed perihematomal edema. Conclusion— The MRI profile of the presumed perihematomal edema in acute intracerebral hemorrhage exhibits delayed perfusion and increased diffusivity mixed with areas of reduced diffusion.
Journal of Neurosurgery | 2012
Joshua Loya; Stefan A. Mindea; Hong Yu; Chitra Venkatasubramanian; Steven D. Chang; Terry C. Burns
Intracranial hypotension is a disorder of CSF hypovolemia due to iatrogenic or spontaneous spinal CSF leakage. Rarely, positional headaches may progress to coma, with frequent misdiagnosis. The authors review reported cases of verified intracranial hypotension-associated coma, including 3 previously unpublished cases, totaling 29. Most patients presented with headache prior to neurological deterioration, with positional symptoms elicited in almost half. Eight patients had recently undergone a spinal procedure such as lumbar drainage. Diagnostic workup almost always began with a head CT scan. Subdural collections were present in 86%; however, intracranial hypotension was frequently unrecognized as the underlying cause. Twelve patients underwent one or more procedures to evacuate the collections, sometimes with transiently improved mental status. However, no patient experienced lasting neurological improvement after subdural fluid evacuation alone, and some deteriorated further. Intracranial hypotension was diagnosed in most patients via MRI studies, which were often obtained due to failure to improve after subdural hematoma (SDH) evacuation. Once the diagnosis of intracranial hypotension was made, placement of epidural blood patches was curative in 85% of patients. Twenty-seven patients (93%) experienced favorable outcomes after diagnosis and treatment; 1 patient died, and 1 patient had a morbid outcome secondary to duret hemorrhages. The literature review revealed that numerous additional patients with clinical histories consistent with intracranial hypotension but no radiological confirmation developed SDH following a spinal procedure. Several such patients experienced poor outcomes, and there were multiple deaths. To facilitate recognition of this treatable but potentially life-threatening condition, the authors propose criteria that should prompt intracranial hypotension workup in the comatose patient and present a stepwise management algorithm to guide the appropriate diagnosis and treatment of these patients.
Stroke Research and Treatment | 2011
Anna Finley Caulfield; Shylaja Rachabattula; Irina Eyngorn; Scott Hamilton; Rajalakshmi Kalimuthu; Amie W. Hsia; Maarten G. Lansberg; Chitra Venkatasubramanian; Jj Baumann; Marion S. Buckwalter; Monisha A. Kumar; James Castle; Christine A.C. Wijman
Introduction. We sought to compare the performance of endovascular cooling to conventional surface cooling after cardiac arrest. Methods. Patients in coma following cardiopulmonary resuscitation were cooled with an endovascular cooling catheter or with ice bags and cold-water-circulating cooling blankets to a target temperature of 32.0–34.0°C for 24 hours. Performance of cooling techniques was compared by (1) number of hourly recordings in target temperature range, (2) time elapsed from the written order to initiate cooling and target temperature, and (3) adverse events during the first week. Results. Median time in target temperature range was 19 hours (interquartile range (IQR), 16–20) in the endovascular group versus. 10 hours (IQR, 7–15) in the surface group (P = .001). Median time to target temperature was 4 (IQR, 2.8–6.2) and 4.5 (IQR, 3–6.5) hours, respectively (P = .67). Adverse events were similar. Conclusion. Endovascular cooling maintains target temperatures better than conventional surface cooling.
Journal of the American Heart Association | 2013
Didem Aksoy; Roland Bammer; Michael Mlynash; Chitra Venkatasubramanian; Irina Eyngorn; Ryan W Snider; Sandeep N. Gupta; Rashmi Narayana; Nancy J. Fischbein; Christine A.C. Wijman
Background Spontaneous intracerebral hemorrhage (ICH) is associated with blood–brain barrier (BBB) injury, which is a poorly understood factor in ICH pathogenesis, potentially contributing to edema formation and perihematomal tissue injury. We aimed to assess and quantify BBB permeability following human spontaneous ICH using dynamic contrast‐enhanced magnetic resonance imaging (DCE MRI). We also investigated whether hematoma size or location affected the amount of BBB leakage. Methods and Results Twenty‐five prospectively enrolled patients from the Diagnostic Accuracy of MRI in Spontaneous intracerebral Hemorrhage (DASH) study were examined using DCE MRI at 1 week after symptom onset. Contrast agent dynamics in the brain tissue and general tracer kinetic modeling were used to estimate the forward leakage rate (Ktrans) in regions of interest (ROI) in and surrounding the hematoma and in contralateral mirror–image locations (control ROI). In all patients BBB permeability was significantly increased in the brain tissue immediately adjacent to the hematoma, that is, the hematoma rim, compared to the contralateral mirror ROI (P<0.0001). Large hematomas (>30 mL) had higher Ktrans values than small hematomas (P<0.005). Ktrans values of lobar hemorrhages were significantly higher than the Ktrans values of deep hemorrhages (P<0.005), independent of hematoma volume. Higher Ktrans values were associated with larger edema volumes. Conclusions BBB leakage in the brain tissue immediately bordering the hematoma can be measured and quantified by DCE MRI in human ICH. BBB leakage at 1 week is greater in larger hematomas as well as in hematomas in lobar locations and is associated with larger edema volumes.
Cerebrovascular Diseases | 2010
Christine A.C. Wijman; Chitra Venkatasubramanian; Sara Bruins; Nancy J. Fischbein; Neil E. Schwartz
Background: The optimal diagnostic evaluation for spontaneous intracerebral hemorrhage (ICH) remains controversial. In this retrospective study, we assessed the utility of early magnetic resonance imaging (MRI) in ICH diagnosis and management. Methods: Eighty-nine (72%) of 123 patients with spontaneous ICH underwent a brain CT and MRI within 30 days of ICH onset. Seventy patients with a mean age of 62 ± 15 years were included. A stroke neurologist and a general neurologist, each blinded to the final diagnosis, independently reviewed the admission data and the initial head CT and then assigned a presumed ICH cause under 1 of 9 categories. ICH cause was potentially modified after subsequent MRI review. The final ‘gold standard’ ICH etiology was determined after review of the complete medical record by an independent investigator. Change in diagnostic category and confidence and the potential impact on patient management were systematically recorded. Results: Mean time to MRI was 3 ± 5 days. Final ICH diagnosis was hypertension or cerebral amyloid angiopathy (CAA) in 50% of patients. After MRI review the stroke neurologist changed diagnostic category in 14%, diagnostic confidence in an additional 23% and management in 20%, and the general neurologist did so in 19, 21 and 21% of patients, respectively. MRI yield was highest in ICH secondary to ischemic stroke, CAA, vascular malformations and neoplasms, and did not differ by age, history of hypertension, hematoma location or the presence of intraventricular hemorrhage. Conclusions: The results of this study suggest potential additive clinical benefit of early MRI in patients with spontaneous ICH.
Journal of the American Heart Association | 2013
Chitra Venkatasubramanian; Jonathan T. Kleinman; Nancy J. Fischbein; Jean-Marc Olivot; Alisa D. Gean; Irina Eyngorn; Ryan W Snider; Michael Mlynash; Christine A.C. Wijman
Background The purpose of this study was to define the incidence, imaging characteristics, natural history, and prognostic implication of corticospinal tract Wallerian degeneration (CST‐WD) in spontaneous intracerebral hemorrhage (ICH) using serial MR imaging. Methods and Results Consecutive ICH patients with supratentorial ICH prospectively underwent serial MRIs at 2, 7, 14, and 21 days. MRIs were analyzed by independent raters for the presence and topographical distribution of CST‐WD on diffusion‐weighted imaging (DWI). Baseline demographics, hematoma characteristics, ICH score, and admission National Institute of Health Stroke Score (NIHSS) were systematically recorded. Functional outcome at 3 months was assessed by the modified Rankin Scale (mRS) and the motor‐NIHSS. Twenty‐seven patients underwent 93 MRIs; 88 of these were serially obtained in the first month. In 13 patients (48%), all with deep ICH, CST‐WD changes were observed after a median of 7 days (interquartile range, 7 to 8) as reduced diffusion on DWI and progressed rostrocaudally along the CST. CST‐WD changes evolved into T2‐hyperintense areas after a median of 11 days (interquartile range, 6 to 14) and became atrophic on MRIs obtained after 3 months. In univariate analyses, the presence of CST‐WD was associated with poor functional outcome (ie, mRS 4 to 6; P=0.046) and worse motor‐NIHSS (5 versus 1, P=0.001) at 3 months. Conclusions Wallerian degeneration along the CST is common in spontaneous supratentorial ICH, particularly in deep ICH. It can be detected 1 week after ICH on DWI and progresses rostrocaudally along the CST over time. The presence of CST‐WD is associated with poor motor and functional recovery after ICH.
Neurology | 2010
Gregory Kapinos; Nancy J. Fischbein; Greg Zaharchuk; Chitra Venkatasubramanian
Migraine with prolonged aura can mimic an acute ischemic stroke (AIS), as each may present with accompanying headache and focal neurologic deficits. During the acute episode, perfusion imaging like perfusion-weighted MRI (PWI) can show focal abnormalities corresponding to the neurologic deficits in both entities, making clinical distinction challenging, especially considering the time urgency of AIS treatment. In this case report, we discuss how we utilized hyperacute PWI in conjunction with clinical reasoning to propose the diagnosis of migraine-like headache with prolonged aura. ### Case report. A 46-year-old woman presented to the emergency department within 1 hour of sudden onset of bilateral tunnel vision. Over several minutes, this evolved into a right upper quadrant arc-shaped scotoma and then to right homonymous hemianopsia. She also developed a severe nonthrobbing right retro-orbital headache, which progressed to the bilateral occipital area with right face and arm paresthesias. Past history included allergy to iodinated contrast, Ehlers-Danlos type IV, and several years of frequent severe unilateral throbbing headaches with photophobia/phonophobia and nausea as a teenager. She had to miss school, had no aura, and had not been diagnosed with migraine, but her mother carried this diagnosis. Examination revealed right homonymous hemianopsia, decreased pinprick over the right face and arm, with no motor deficits, nuchal rigidity, or bruits (NIH Stroke Scale = 3). Vital signs and noncontrast head CT were normal. To exclude AIS, we obtained an emergent gadolinium-enhanced MRI with diffusion-weighted imaging, PWI, and magnetic resonance angiogram (MRA) of the head and neck, 150 minutes after symptom onset (figure). The MRI did not demonstrate any area of reduced diffusion, vascular occlusion, abnormal arterial caliber, or dissection. Thrombolytic was not administered and the remaining magnetic resonance sequences revealed normal fluid-attenuated inversion recovery (FLAIR). After the MRI, …
Neurocritical Care | 2015
Rachel E Garvin; Chitra Venkatasubramanian; Angela Lumba-Brown; Chad Miller
Abstract Traumatic Brain Injury (TBI) was chosen as an Emergency Neurological Life Support topic due to its frequency, the impact of early intervention on outcomes for patients with TBI, and the need for an organized approach to the care of such patients within the emergency setting. This protocol was designed to enumerate the practice steps that should be considered within the first critical hour of neurological injury.
Neurosurgery Clinics of North America | 2006
Christine A.C. Wijman; Chitra Venkatasubramanian
Elevated blood pressure (BP) is exceedingly common in patients who present with an acute spontaneous intracerebral hemorrhage (ICH). Many pharmacologic agents are available to rapidly decrease elevated BP in these patients, but m the absence of evidence-based guidelines, controversy remains on the optimal BP target [1 ]. In a recent worldwide survey among 117 stroke experts caring for patients with acute ICH, 56% of physicians reported using a uniform BP goal within the first 24 hours [21. Of these, the majority (n = 50) preferred a systolic blood pressure (SBP) goal rather than a mean arterial pressure (MAP) goal. ~II~e SBP target, however, diflered substantially among physicians (Fig. 1). On one hand, elevated BP may contribute to hematoma expansion and edema formation in the hours to days after symptom onset. Conversely, aggressive BP lowering might impair regional cerebral blood flow (CBF) and cause ischemia and secondary tissue injury in the brain region surrounding the hematoma. In this article, we review the current available literature addressing each side of the argmnent.