Background Therapeutic hypothermia is commonly used in comatose survivors’ post-cardiopulmonary resuscitation (CPR). It is unknown whether outcome predictors perform accurately after hypothermia treatment. Methods Post-CPR comatose survivors were prospectively enrolled. Six outcome predictors [pupillary and corneal reflexes, motor response to pain, and somatosensory-evoked potentials (SSEP) >72 h; status myoclonus, and serum neuron-specific enolase (NSE) levels <72 h] were systematically recorded. Poor outcome was defined as death or vegetative state at 3 months. Patients were considered “sedated” if they received any sedative drugs ≤12 h prior the 72 h neurological assessment. Results Of 85 prospectively enrolled patients, 53 (62%) underwent hypothermia. Furthermore, 53 of the 85 patients (62%) had a poor outcome. Baseline characteristics did not differ between the hypothermia and normothermia groups. Sedative drugs at 72 h were used in 62 (73%) patients overall, and more frequently in hypothermia than in normothermia patients: 83 versus 60% (P = 0.02). Status myoclonus <72 h, absent cortical responses by SSEPs >72 h, and absent pupillary reflexes >72 h predicted poor outcome with a 100% specificity both in hypothermia and normothermia patients. In contrast, absent corneal reflexes >72 h, motor response extensor or absent >72 h, and peak NSE >33 ng/ml <72 h predicted poor outcome with 100% specificity only in non-sedated patients, irrespective of prior treatment with hypothermia. Conclusions Sedative medications are commonly used in proximity of the 72-h neurological examination in comatose CPR survivors and are an important prognostication confounder. Patients treated with hypothermia are more likely to receive sedation than those who are not treated with hypothermia.

Objective-Outcome prediction is challenging in comatose post-cardiac arrest survivors. We assessed the feasibility and prognostic utility of brain diffusion-weighted MRI (DWI) during the first week.Corresponding Author Christine AC Wijman, MD, PhD, Stanford Stroke Center, 701 Welch Road, B325, Palo Alto, CA 94304, Fax: (650) Tel: (650) NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptMethods-Consecutive comatose post-cardiac arrest patients were prospectively enrolled. MRI data of patients who met predefined specific prognostic criteria were used to determine distinguishing ADC thresholds. Group 1: death at 6 months and absent motor response or absent pupillary reflexes or bilateral absent cortical responses at 72 hours, or vegetative at 1 month. Group 2A: Glasgow outcome scale (GOS) score of 4 or 5 at 6 months. Group 2B: GOS of 3 at 6 months. The percentage of voxels below different apparent diffusion coefficient (ADC) thresholds was calculated at 50 × 10 −6 mm 2 /sec intervals.Results-Overall, 86% of patients underwent MR imaging. Fifty-one patients with 62 brain MRIs were included in the analyses. Forty patients met the specific prognostic criteria. The percentage of brain volume with an ADC value below 650-700 × 10 −6 mm 2 /sec best differentiated between group 1 and groups 2A and 2B combined (p<0.001), while the 400-450 × 10 −6 mm 2 /sec threshold best differentiated between groups 2A and 2B (p=0.003). The ideal time window for prognostication using DWI was between 49 to 108 hours after the arrest. When comparing MRI in this time window with the 72 hour neurological examination MRI improved the sensitivity for predicting poor outcome by 38% while maintaining 100% specificity (p=0.021).Interpretation-Quantitative DWI in comatose post-cardiac arrest survivors holds great promise as a prognostic adjunct.Approximately 350,000 cardiac arrests occur annually in the United States1. Up to half of these patients are successfully resuscitated. In the past, only 10% to 30% of comatose postcardiac arrest patients had good functional recovery. These numbers will likely improve with the increasing use of therapeutic hypothermia2 , 3.Post-cardiac arrest brain injury is a common cause of morbidity and mortality. Many comatose post-cardiac arrest patients die or survive with severe disability after a prolonged intensive care unit stay associated with a tremendous cost burden4 , 5. Conversely, the potential for premature withdrawal of life support from patients who may have a chance of functional recovery represents an additional ethical dilemma. Thus, early accurate identification of patients who have no likelihood of meaningful recovery is a very important health care issue.Although several prognostic variables have been studied in comatose post-cardiac arrest patients, the currently accepted variables (neurological examination, neurophysiologic tests, and serum markers) have substantive limitations. First, they identify only a subset of poor outcome patients with high specificity. Se...

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 Ն5 cm 3 underwent serial MRIs at prespecified intervals during the first month. Hematoma (H v ) and PHE (E v ) volumes were measured on fluid-attenuated inversion recovery images. Relative PHE was defined as E v /H v . 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 H v and E v on the first MRI were 39 and 46 cm 3 , respectively. Median peak absolute E v was 88 cm 3 . Larger hematomas produced a larger absolute E v (r 2 ϭ0.6) and a smaller relative PHE (r 2 ϭ0.7). Edema volume growth was fastest in the first 2 days but continued until 12Ϯ3 days. In multivariate analysis, a higher admission hematocrit was associated with a greater delay in peak PHE (Pϭ0.06). Higher admission partial thromboplastin time was associated with higher peak rPHE (Pϭ0.02). Edema volume growth was correlated with a decline in neurologic status at 48 hours (81 vs 43

Background and Purpose-Diffusion-weighted magnetic resonance imaging of the brain is a promising technique to help predict functional outcome in comatose survivors of cardiac arrest. We aimed to evaluate prospectively the temporal-spatial profile of brain apparent diffusion coefficient changes in comatose survivors during the first 8 days after cardiac arrest. Methods-Apparent diffusion coefficient values were measured by 2 independent and blinded investigators in predefined brain regions in 18 good-and 15 poor-outcome patients with 38 brain magnetic resonance imaging scans and were compared with those of 14 normal controls. The same brain regions were also assessed qualitatively by 2 other independent and blinded investigators. Results-In poor-outcome patients, cortical structures, in particular the occipital and temporal lobes, and the putamen exhibited the most profound apparent diffusion coefficient reductions, which were noted as early as 1.5 days and reached a nadir between 3 and 5 days after the arrest. Conversely, when compared with normal controls, good-outcome patients exhibited increased diffusivity, in particular in the hippocampus, temporal and occipital lobes, and corona radiata. By qualitative magnetic resonance imaging readings, 1 or more cortical gray matter structures were judged to be moderately to severely abnormal in all poor-outcome patients except for the 3 patients imaged within 24 hours after the arrest. Conclusions-Brain diffusion-weighted imaging changes in comatose, postcardiac arrest survivors in the first week after the arrest are region and time dependent and differ between good-and poor-outcome patients. With increasing use of magnetic resonance imaging in this context, it is important to be aware of these relations. (Stroke. 2010;41:1665-1672.)

Objective: Transient ischemic attacks (TIA) predict future stroke. However, there are no sensitive and specific diagnostic criteria for TIA and interobserver agreement regarding the diagnosis is poor. Diffusion-weighted MRI (DWI) demonstrates acute ischemic lesions in approximately 30% of TIA patients; the yield of perfusion-weighted MRI (PWI) is unclear. Methods:We prospectively performed both DWI and PWI within 48 hours of symptom onset in consecutive patients admitted with suspected hemispheric TIAs of Ͻ24 hours symptom duration. Two independent raters, blinded to clinical features, assessed the presence and location of acute DWI and PWI lesions. Lesions were correlated with suspected clinical localization and baseline characteristics. Clinical features predictive of a PWI lesion were assessed. Results:Forty-three patients met the inclusion criteria. Thirty-three percent had a PWI lesion and 35% had a DWI lesion. Seven patients (16%) had both PWI and DWI lesions and 7 (16%) had only PWI lesions. The combined yield for identification of either a PWI or a DWI was 51%. DWI lesions occurred in the clinically suspected hemisphere in 93% of patients; PWI lesions in 86%. PWI lesions occurred more frequently when the MRI was performed within 12 hours of symptom resolution, in patients with symptoms of speech impairment, and among individuals younger than 60 years. Transient ischemic attacks (TIA) are defined as sudden, temporary attacks (Ͻ24 hours) with focal symptoms attributable to dysfunction of one artery of the brain. The risk of stroke after a TIA is up to 10% in the first week following symptom onset. Conclusions:1 Recent studies demonstrated that a prompt etiologic investigation followed by the initiation of an appropriate prevention strategy can substantially reduce this risk.2,3 Hence, confirmation of the diagnosis of TIA is a major challenge since in most cases the clinical deficit has resolved at the time of evaluation and conventional brain imaging does not detect most conditions that masquerade as a TIA. 4 In multimodal MRI, diffusion-weighted imaging (DWI) demonstrates the presence of severe cytotoxic ischemic injury within minutes, which provides an estimate of the ischemic core, 5,6 and perfusion-weighted imaging (PWI) provides an assessment of cerebral hemodynamics.

ObjectiveTo validate quantitative diffusion-weighted imaging (DWI) MRI thresholds that correlate with poor outcome in comatose cardiac arrest survivors, we conducted a clinician-blinded study and prospectively obtained MRIs from comatose patients after cardiac arrest.MethodsConsecutive comatose post-cardiac arrest adult patients were prospectively enrolled. MRIs obtained within 7 days after arrest were evaluated. The clinical team was blinded to the DWI MRI results and followed a prescribed prognostication algorithm. Apparent diffusion coefficient (ADC) values and thresholds differentiating good and poor outcome were analyzed. Poor outcome was defined as a Glasgow Outcome Scale score of ≤2 at 6 months after arrest.ResultsNinety-seven patients were included, and 75 patients (77%) had MRIs. In 51 patients with MRI completed by postarrest day 7, the prespecified threshold of >10% of brain tissue with an ADC <650 ×10−6 mm2/s was highly predictive for poor outcome with a sensitivity of 0.63 (95% confidence interval [CI] 0.42–0.80), a specificity of 0.96 (95% CI 0.77–0.998), and a positive predictive value (PPV) of 0.94 (95% CI 0.71–0.997). The mean whole-brain ADC was higher among patients with good outcomes. Receiver operating characteristic curve analysis showed that ADC <650 ×10−6 mm2/s had an area under the curve of 0.79 (95% CI 0.65–0.93, p < 0.001). Quantitative DWI MRI data improved prognostication of both good and poor outcomes.ConclusionsThis prospective, clinician-blinded study validates previous research showing that an ADC <650 ×10−6 mm2/s in >10% of brain tissue in an MRI obtained by postarrest day 7 is highly specific for poor outcome in comatose patients after cardiac arrest.

A qualitative MRI scoring system helps assess hypoxic-ischemic brain injury severity following cardiac arrest and may provide useful prognostic information in comatose cardiac arrest patients.

In patients who remain comatose after cardiac arrest, quantitative DWI MRI findings correlate with early recovery of consciousness. A DWI MRI threshold of 650 × 10(-6) mm(2)/s in ≥10% of brain volume can differentiate patients with good versus poor outcome, though in this patient population the threshold was not 100% specific for poor outcome.