Computed tomography and magnetic resonance imaging findings in central nervous system listeriosis.

PURPOSE: To describe the imaging findings and determine the incidence of a characteristic worm-like pattern along the white matter tracts in neurolisteriosis on CT/MRI. METHODS: An IRB-approved retrospective study in 21 consecutive neurolisteriosis cases during January 2002-July 2020. At least one of the following is required: (1) Positive Listeria monocytogenes (LM) in blood with clinical signs of meningeal irritation and/or abnormal CSF profile, (2) positive LM in blood with signs of encephalitis, (3) positive LM in CSF, (4) positive LM from brain biopsy/aspiration. Six cases were excluded due to the lack of contrast-enhanced images, leaving a total of 15 cases for analysis (mean age 53.5 years ± 18.8 SD). The imaging studies were independently reviewed by two blinded readers. Demographic data, imaging findings, and incidence of the worm-like pattern were reported. The Cohen's kappa was used to calculate interrater reproducibility. RESULTS: Of the 12 patients with relevant imaging findings, nine cases (75%) had parenchymal lesions (eight cases in supratentorial compartment and one case in infratentorial compartment), four cases (33.3%) had leptomeningeal enhancement and two cases (16.7%) had hydrocephalus. Brain abscesses were found in eight cases and nodules evocative of abscess in one case. Restricted diffusion in the central area and hemosiderin deposition were observed in all cases. The involvement of white matter tract in a worm-like pattern was demonstrated in eight of nine patients with parenchymal lesions (88.9%). CONCLUSION: Abnormal findings in brain CT/MRI images are common in neurolisteriosis. The incidence of worm-like spread along the white matter tracts is high and may help diagnose suspicious patients.

High-density electric source imaging patterns and outcomes following temporal lobectomy in patients with hippocampal sclerosis.

OBJECTIVE: The objective of this study was to ascertain specific patterns of electrical source imaging (ESI) that are associated with a good surgical outcome (no seizure recurrence) using 256-channel high-density (HD) electroencephalography (EEG) in patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) who underwent temporal lobectomy. METHODS: Adult patients (age ≥ 18 years) were prospectively recruited from September 2016 to May 2020 at the authors' center. All patients underwent phase I presurgical evaluation and were subsequently advised to proceed with surgery based on consensus from a multidisciplinary epilepsy conference, without knowing HD-ESI results. All recruited patients were followed for at least 12 months after surgery. The outcome of interest was a status of no seizure recurrence, which was assessed at the end of the study. The association between ESI patterns and outcome was assessed using the chi-square or Fisher exact test. Associated p values as well as odds ratios and 95% CIs were reported. The diagnostic performance of the significant pattern associated with the outcome was also evaluated. RESULTS: Fifty-eight patients with known predictors for either good or worse surgical outcomes were recruited. The mean postoperative follow-up period was 33.34 (SD 13.88) months. Forty-seven patients had sufficient interictal epileptiform discharges for HD-ESI analysis. Thirteen of these 47 patients experienced seizure recurrence. The most common source localizations were at Brodmann area (BA) 20 (inferior temporal area) and BA 21 (middle temporal area). A specific ESI pattern of BA 21 without extratemporal sources was significantly associated with no seizure recurrence (p = 0.047). This pattern had a high positive predictive value of 100% and false-positive rate of 0% associated with no seizure recurrence following the surgery. CONCLUSIONS: A specific ESI pattern that was highly associated with no seizure recurrence following surgery was demonstrated by a 256-channel HD-EEG. If this pattern can be reproducibly proven in further studies, some TLE-HS patients may be able to proceed with surgery without further investigations.

Mid-cervical flame-shaped pseudo-occlusion: diagnostic performance of mid-cervical flame-shaped extracranial internal carotid artery sign on computed tomographic angiography in hyperacute ischemic stroke.

PURPOSE: Flame-shaped pseudo-occlusion of the extracranial internal carotid artery (ICA) is a flow-related phenomenon that creates computed tomographic angiography (CTA) and digital subtraction angiography (DSA) findings that mimic tandem intracranial-extracranial ICA occlusion or dissection. We aim to determine the diagnostic performance of mid-cervical flame-shaped extracranial ICA sign on CTA in hyperacute ischemic stroke patients. METHODS: We retrospectively included consecutive anterior circulation ischemic stroke patients presenting within 6 h of symptom onset who underwent 4D brain CTA and arterial-phase neck CTA using a 320-detector CT scanner during August 2012 to July 2015. Two blinded readers independently reviewed arterial-phase neck CTA and characterized the extracranial ICA configurations into mid-cervical flame-shaped, proximal blunt/beak-shaped, and tubular-shaped groups. 4D whole brain CTA was used as a reference standard for intracranial ICA occlusion detection. Diagnostic performance of the mid-cervical flame-shaped extracranial ICA sign and interobserver reliability were calculated. RESULTS: Of the 81 cases, 11 had isolated intracranial ICA occlusion, and 6 had true extracranial ICA occlusion. Mid-cervical flame-shaped extracranial ICA sign was found in 45.5% (5/11) of isolated intracranial ICA occlusions but none in the true extracranial ICA occlusion group. The sensitivity, specificity, PPV, NPV, and accuracy of the mid-cervical flame-shaped extracranial ICA sign for the detection of isolated intracranial ICA occlusion were 45.5, 100, 100, 92.1, and 92.6%, respectively. Interobserver reliability was 0.90. CONCLUSION: The mid-cervical flame-shaped extracranial ICA sign may suggest the presence of isolated intracranial ICA occlusion and allow reliable exclusion of tandem extracranial-intracranial ICA occlusion in hyperacute ischemic stroke setting.

ASPECTS CT in Acute Ischemia: Review of Current Data.

The Alberta Stroke Program Early CT score (ASPECTS) is a 10-point semiquantitative topographic scoring system developed for the assessment of early ischemic changes (EICs) on noncontrast-enhanced computed tomography (NCCT) in patients with acute ischemic stroke involving the middle cerebral artery (MCA) territory. One point is subtracted from a total score of 10, if an EIC is present in any part of each of the ASPECTS regions. Higher ASPECTS has been associated with better outcomes and a lower risk of symptomatic intracerebral hemorrhage. To date, there are still controversies regarding the utility of ASPECTS for selecting patients for intravenous and intra-arterial therapies. This article provides a comprehensive review regarding methodology, limitations, and interobserver reproducibility of ASPECTS, as well as application of ASPECTS in clinical care. The focus of this review is ASPECTS evaluation on NCCT. The application of ASPECTS on multimodal computed tomography and magnetic resonance imaging (MRI) is briefly described.

MRI Patterns of Isolated Lesions in the Medulla Oblongata.

BACKGROUND AND PURPOSE: Isolated lesions of the medulla oblongata are difficult to diagnose due to their rarity and high biopsy risk. Several individual case reports have been published, but a systematic descriptive study is lacking. Our study has three objectives that 1) provide a differential diagnosis, 2) describe magnetic resonance imaging (MRI) findings, and 3) propose a stepwise MRI-based approach to the isolated lesions of the medulla oblongata in nonstroke patients. METHODS: We performed an institutional Review Board-approved retrospective analysis of 34 consecutive cases of isolated medullary lesions from nonstroke causes identified from our imaging database between January 2000 and May 2015. Eleven were excluded due to lack of pretreatment or follow-up MRI. MR studies were reviewed by two blinded neuroradiologists. The diagnosis, demographic data, and MR findings were reported using frequencies and proportions. An MRI-based diagnostic algorithm was proposed. RESULTS: Most lesions were neoplasms (47%), followed by vascular malformations (15%), demyelinating/inflammatory lesions (15%), others (12%), unknown (8%), and infection (3%). Five MRI patterns were identified: 1) cystic lesion, 2) exophytic noncystic lesion, 3) intrinsic lesion with T2 hypointensity, 4) enhancing intrinsic lesion, and 5) nonenhancing intrinsic lesion. All showing patterns 1 and 2 were neoplasms or cysts. All showing pattern 3 were vascular malformations. Patterns 4 and 5 comprised of multiple etiologies. CONCLUSIONS: Neoplasms are the most common cause of isolated medullary lesions in nonstroke patients. Other differential diagnoses include vascular malformations, demyelinating/inflammatory lesions, and infections. A stepwise MRI-based approach can help differentiate between various etiologies.

Ultrafast Brain MRI: Clinical Deployment and Comparison to Conventional Brain MRI at 3T.

BACKGROUND AND PURPOSE: To compare an ultrafast brain magnetic resonance imaging (MRI) protocol to the conventional protocol in motion-prone inpatient clinical settings. METHODS: This retrospective study was HIPAA compliant and approved by the Institutional Review Board with waived inform consent. Fifty-nine inpatients (30 males, 29 females; mean age 55.1, range 23-93 years)who underwent 3-Tesla brain MRI using ultrafast and conventional protocols, both including five sequences, were included in the study. The total scan time for five ultrafast sequences was 4 minutes 59 seconds. The ideal conventional acquisition time was 10 minutes 32 seconds but the actual acquisition took 15-20 minutes. The average scan times for ultrafast localizers, T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted, T2*-weighted sequences were 14, 41, 62, 96, 80, 6 seconds, respectively. Two blinded neuroradiologists independently assessed three aspects: (1) image quality, (2) gray-white matter (GM-WM) differentiation, and (3) diagnostic concordance for the detection of six clinically relevant imaging findings. Wilcoxon signed-rank test was used to compare image quality and GM-WM scores. Interobserver reproducibility was calculated. RESULTS: The ultrafast T1-weighted sequence demonstrated significantly better image quality (P = .005) and GM-WM differentiation (P < .001) compared to the conventional sequence. There was high agreement (>85%) between both protocols for the detection of mass-like lesion, hemorrhage, diffusion restriction, WM FLAIR hyperintensities, subarachnoid FLAIR hyperintensities, and hydrocephalus. CONCLUSIONS: The ultrafast protocol achieved at least comparable image quality and high diagnostic concordance compared to the conventional protocol. This fast protocol can be a viable option to replace the conventional protocol in motion-prone inpatient clinical settings.