Conventional MRI does not reliably distinguish radiation necrosis from tumor recurrence after stereotactic radiosurgery.

Distinguishing radiation necrosis (RN) from tumor recurrence after stereotactic radiosurgery (SRS) for brain metastases is challenging. This study assesses the sensitivity (SN) and specificity (SP) of an MRI-based parameter, the "lesion quotient" (LQ), in characterizing tumor progression from RN. Records of patients treated with SRS for brain metastases between 01/01/1999 and 12/31/2009 and with histopathologic analysis of a subsequent contrast enhancing enlarging lesion at the treated site at a single institution were examined. The LQ, the ratio of maximal nodular cross sectional area on T2-weighted imaging to the corresponding maximal cross sectional area of T1-contrast enhancement, was calculated by a neuroradiologist blinded to the histopathological outcome. Cutoffs of <0.3, 0.3-0.6, and >0.6 have been previously suggested to have correlated with RN, mixed findings and tumor recurrence, respectively. These cutoff values were evaluated for SN, SP, positive predictive value (PPV) and negative predictive value (NPV). Logistic regression analysis evaluated for associated clinical factors. For the 51 patients evaluated, the SN, SP, PPV and NPV for identifying RN (LQ < 0.3) were 8, 91, 25 and 73 %, respectively. For the combination of recurrent tumor and RN (LQ 0.3-0.6) the SN, SP, PPV and NPV were 0, 64, 0 and 83 %. The SN, SP, PPV and NPV of the LQ for recurrent tumor (LQ > 0.6) were 59, 41, 62 and 39 %, respectively. Standard MRI techniques do not reliably discriminate between tumor progression and RN after treatment with SRS for brain metastases. Additional imaging modalities are warranted to aid in distinguishing between these diagnoses.

A 5-item scale to predict stroke outcome after cortical middle cerebral artery territory infarction: validation from results of the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) Study.

BACKGROUND AND PURPOSE: Various clinical, laboratory, and radiographic parameters have been identified as predictors of outcome for ischemic stroke. The purpose of this study was to combine these parameters into a validated scale for outcome prognostication in patients with a middle cerebral artery territory infarction. METHODS: We retrospectively reviewed 129 patients over a 2-year period and considered demographic, clinical, laboratory, and radiographic parameters as potential predictors of outcome. Inclusion criteria were unilateral hemispheric infarcts within the middle cerebral artery territory >15 mm in diameter. Our primary outcome measure was a favorable recovery defined as a modified Rankin Score was ≤2 at 30 days. A multivariable model was used to determine independent predictors of outcome and weighted to create a 5-item scale to predict stroke recovery. External validation of this model was done using data from the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) study. RESULTS: The 5 independent predictors of outcome were as follows: age (OR, 1.09; 95% CI, 1.03 to 1.14; P=0.001), National Institutes of Health Stroke Scale score (OR, 1.17; 95% CI, 1.06 to 1.30; P=0.003), infarct volume (OR, 1.01; 95% CI, 1.00 to 1.02; P=0.03), admission white blood cell count (8.5×10(3)/mm(3); OR, 1.16; 95% CI, 1.03 to 1.27; P=0.04), and presence of hyperglycemia (OR, 4.2; 95% CI, 1.1 to 16.4; P=0.04). Combining these variables into a point scale significantly improved prediction over the individual variables accounted alone as evidenced by the area underneath the receiver operating curve (OR, 0.91; 95% CI, 0.87 to 0.96; P=0.0001). When applied to the DEFUSE study population for validation, the model achieved a sensitivity of 83% and specificity of 86%. CONCLUSIONS: With validation from a prospective study of similar patients, this model serves as a useful clinical and research tool to predict stroke recovery after cortical middle cerebral artery territory infarction.

Statin use is independently associated with smaller infarct volume in nonlacunar MCA territory stroke.

BACKGROUND: Studies have shown an association between HMG-CoA reductase inhibitors (statins) and improved stroke outcomes, possibly secondary to neuroprotective properties. OBJECTIVE: To assess whether patients taking statins prior to ischemic stroke have smaller infarcts on magnetic resonance imaging (MRI), adjusting for other relevant clinical factors. DESIGN: We retrospectively reviewed the Cleveland Clinic Foundation (CCF) Neurology Inpatient Database from June 2002 through June 2004. Demographics, medications, stroke subtype, diffusion-weighted imaging (DWI) infarct volume, admission NIHSS, and hours to MRI were collected. Patients with a nonlacunar middle cerebral artery (MCA) territory infarct and MRI less than 48 hours from symptom onset were included (n= 143). A multivariable linear regression model was constructed to determine independent predictors of smaller infarct volume. RESULTS: A total of 143 patients were studied, including 38 patients taking statins at the time of their stroke. In univariate analysis, patients using statins were significantly more likely to have a history of hyperlipidemia, atrial fibrillation, and coronary artery disease and to be using coumadin, antiplatelet drugs, and angiotensin-converting enzyme inhibitors. Patients on statins had a tendency toward smaller infarcts in univariate analysis (median 25.4 cm(3) vs. 15.5 cm(3), P= 0.054). In multivariable linear regression analysis statin use, patient age, and TIA within the prior 4 weeks were independently associated with smaller DWI volumes; vessel occlusion on vascular imaging, and cardioembolic stroke subtype with larger infarct size. CONCLUSIONS: Statin use prior to the onset of nonlacunar MCA infarction was associated with a smaller infarct volume independent of other factors. Further studies utilizing both clinical and radiologic outcomes will be required to confirm these findings.