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Background: Brain magnetic resonance imaging (MRI) is frequently obtained in patients with infective endocarditis, yet its utility in predicting outcomes for valve replacement surgery in patients is unknown. The objective of this study was to determine how brain MRI findings impact clinical management and outcomes., Methods: Demographic and clinical data from electronic medical records at Mayo Clinic were retrospectively reviewed for patients hospitalized with definite or possible infective endocarditis according to the modified Duke criteria between January 1, 2007 and December 31, 2014. There were 364 patients included in the study., Results: Cardiac valve replacement surgery was performed in 195 of 364 (53.6%) patients, and 95 (48.7%) of the surgical patients underwent preoperative MRI, which was associated with preoperative neurologic symptoms in 56 of 95 (58.9%) patients (odds ratio = 12.92; 95% confidence interval, 5.98-27.93; P <.001). Postoperative neurologic complications occurred in 24 of 195 (12.3%) patients, including new ischemic stroke in 4 of 195 (2.1%) and new intracerebral hemorrhage in 3 of 195 (1.5%). No patients with microhemorrhages developed postoperative hemorrhage. No significant differences existed in rates of postoperative complications between patients with and those without preoperative MRI. There were no substantial associations between preoperative MRI findings and postoperative neurologic complications, functional outcomes as described by the modified Rankin Scale score, or 6-month mortality., Conclusions: In patients undergoing valve replacement surgery, preoperative MRI findings were not associated with differences in postoperative outcomes, irrespective of finding or timing of valve replacement surgery., (Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: The prognosis of comatose survivors is determined by clinical examination. Early laboratory indicators of poor prognosis (such as evoked potentials) have low sensitivity. The role of MR imaging as a confirmatory study was investigated., Methods: We studied fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted (DW) imaging in 10 patients comatose after cardiac arrest., Results: None of the 10 comatose patients had myoclonus status epilepticus or fixed, dilated pupils on neurologic examination, and none had abnormal somatosensory-evoked potentials. Eight patients showed diffuse signal abnormalities, predominantly in the cerebellum (n = 5), the thalamus (n = 8), the frontal and parietal cortices (n = 8), and the hippocampus (n = 9). One patient showed normal MR imaging results, and one patient had abnormalities in the thalamus and cerebellum and minimal abnormality on DW images; both later awakened. None of the patients with abnormal cortical structures on FLAIR MR images recovered beyond a severely disabled state., Conclusion: MR imaging in comatose survivors may parallel the pathologic findings in severe anoxic-ischemic injury, and extensive abnormalities may indicate little to no prospects for recovery. If confirmed, MR imaging may have a role as a prognosticating test in anoxic-ischemic coma.

Background and Purpose: The decision to proceed with surgery in cerebellar infarct with mass effect (CIMASS) in deteriorating patients is based on clinical features. The potential role of neuroimaging in predicting deterioration has not been systematically studied. In this study we determine the role of neuroimaging in predicting deterioration in CIMASS., Methods: -We retrospectively reviewed the clinical and neuroimaging features in 90 patients with cerebellar infarcts. We selected for detailed analysis CIMASS in 35 patients., Results: Eighteen patients remained stable and 17 deteriorated. Of these 17 patients, 8 were treated conservatively and 9 had surgery. Radiological features indicative of progression were more common in deteriorating patients compared with stable patients: fourth ventricular shift (82.3% versus 50%, P:=0.075, OR=4. 67), hydrocephalus (76.5% versus 11.1%, P:=0.0001, OR=26), brain stem deformity (47% versus 5.6%, P:=0.0065, OR=15.1), and basal cistern compression (35.3% versus 0%, P:=0.0076, OR=20.91). Differences in upward displacement of the aqueduct and pontomesencephalic junction from Twining's line, tonsillar descent on sagittal MRI, and infarct volumes between stable and deteriorating patients were not statistically significant., Conclusions: Hydrocephalus, brain stem deformity, and basal cistern compression may herald deterioration in CIMASS. Admission to a neurological-neurosurgical intensive care unit and consideration of preemptive surgery are warranted in these patients. Vertical displacement of tonsils or aqueduct, demonstrated by MR imaging, did not predict deterioration.

Background and Purpose: The cause of pretruncal (perimesencephalic) nonaneurysmal subarachnoid hemorrhage is not known. MRI of the brain or spine is often performed to exclude any other vascular abnormalities. Its diagnostic value is not known., Methods: We used MR imaging of the brain with routine sequences, gadolinium enhancement, and additional thin T1-weighted axial sections following a triple dose of contrast., Results: We performed MR imaging of the brain in 18 patients with a pretruncal nonaneurysmal subarachnoid hemorrhage. The focal nature of the subarachnoid hemorrhage exclusively in front of the brain stem was confirmed in 14 patients studied within 7 days of the ictus. No vascular abnormalities were found in 17 cases, including 14 patients with gadolinium enhancement. An incidental capillary telangiectasia was found in 1 patient. Fluid-attenuated inverse recovery MR additionally documented blood in the sulci due to cerebrospinal fluid recirculation of blood. Five patients underwent MR imaging of the spine, and no arteriovenous malformations were found., Conclusions: MR imaging did not reveal a source of pretruncal subarachnoid hemorrhage. The cost of MR imaging probably outweighs the benefit in the evaluation of this variant of subarachnoid hemorrhage.

Some clinicians have challenged the clinicopathologic correlation in patients with brain herniation from acute mass lesions. Earlier studies have questioned the significance of downward displacement of the brainstem in supratentorial herniation. Using recent generation MRI, we studied a patient with an acute hemorrhagic infarction. MRI demonstrated significant compression of the diencephalon with downward displacement of the midbrain and hyperintensity on T2-weighted sequences in the lateral mesencephalon during progression from early diencephalic stage to midbrain upper pons stage of herniation. This is the first intra vitam documentation of diencephalic herniation by MR imaging and confirms rostrocaudal deterioration usually found at autopsy.

We describe a characteristic distribution of cisternal blood in 52 patients with nonaneurysmal subarachnoid hemorrhage proved by a normal angiogram. On CT, the center of the bleeding was located immediately anterior to the brainstem in all patients, which was confirmed in four patients who were studied with MR imaging. Extension to the ambient cisterns or to the basal parts of the sylvian fissures was common, but the lateral sylvian or anterior interhemispheric fissures were never completely filled with blood. Rupture into the ventricular system did not occur. MR demonstrated downward extension of the blood anterior to the brainstem as far as the medulla, but failed to detect the source of hemorrhage. Our aim was to determine whether this so-called nonaneurysmal perimesencephalic hemorrhage could be distinguished from aneurysmal subarachnoid hemorrhage on early CT scans. Two neuroradiologists were shown a consecutive series of 221 CT scans of patients with subarachnoid hemorrhage who subsequently underwent angiography. Only one patient with a basilar artery aneurysm on angiography was incorrectly labeled by both observers as having a nonaneurysmal perimesencephalic pattern of hemorrhage. The high predictive value of the perimesencephalic pattern of hemorrhage for a normal angiogram (0.95 and 0.94, respectively, for the two observers) and the excellent interobserver agreement (kappa 0.87) demonstrate that nonaneurysmal perimesencephalic hemorrhage can be distinguished on CT in the majority of patients. Recognition of this pattern of hemorrhage is important as patients with this subset of subarachnoid hemorrhage have an excellent prognosis.