Neuroimaging of hemorrhage and vascular defects

Abbreviated MRI in the evaluation of dizziness: report turnaround times and impact on length of stay compared to CT, CTA, and conventional MRI

PURPOSE

Neuroimaging is often used in the emergency department (ED) to evaluate for posterior circulation strokes in patients with dizziness, commonly with CT/CTA due to speed and availability. Although MRI offers more sensitive evaluation, it is less commonly used, in part due to slower turnaround times. We assess the potential for abbreviated MRI to improve reporting times and impact on length of stay (LOS) compared to conventional MRI (as well as CT/CTA) in the evaluation of acute dizziness.

MATERIALS AND METHODS

We performed a retrospective analysis of length of stay via LASSO regression for patients presenting to the ED with dizziness and discharged directly from the ED over 4 years (1/1/2018-12/31/2021), controlling for numerous patient-level and logistical factors. We additionally assessed turnaround time between order and final report for various imaging modalities.

RESULTS

14,204 patients were included in our analysis. Turnaround time for abbreviated MRI was significantly lower than for conventional MRI (4.40 h vs. 6.14 h, p < 0.001) with decreased impact on LOS (0.58 h vs. 2.02 h). Abbreviated MRI studies had longer turnaround time (4.40 h vs. 1.41 h, p < 0.001) and was associated with greater impact on ED LOS than non-contrast CT head (0.58 h vs. 0.00 h), however there was no significant difference in turnaround time compared to CTA head and neck (4.40 h vs. 3.86 h, p = 0.06) with similar effect on LOS (0.58 h vs. 0.53 h). Ordering both CTA and conventional MRI was associated with a greater-than-linear increase in LOS (additional 0.37 h); the same trend was not seen combining CTA and abbreviated MRI (additional 0.00 h).

CONCLUSIONS

In the acute settings where MRI is available, abbreviated MRI protocols may improve turnaround times and LOS compared to conventional MRI protocols. Since recent guidelines recommend MRI over CT in the evaluation of dizziness, implementation of abbreviated MRI protocols has the potential to facilitate rapid access to preferred imaging, while minimizing impact on ED workflows.

Cranial Computer Tomography with Photon Counting and Energy-Integrated Detectors: Objective Comparison in the Same Patients

This study provides an objective comparison of cranial computed tomography (CT) imaging quality and radiation dose between photon counting detectors (PCCTs) and energy-integrated detectors (EIDs). We retrospectively analyzed 158 CT scans from 76 patients, employing both detector types on the same individuals to ensure a consistent comparison. Our analysis focused on the Computed Tomography Dose Index and the Dose-Length Product together with the contrast-to-noise ratio and the signal-to-noise ratio for brain gray and white matter. We utilized standardized imaging protocols and consistent patient positioning to minimize variables. PCCT showed a potential for higher image quality and lower radiation doses, as highlighted by this study, thus achieving diagnostic clarity with reduced radiation exposure, underlining its significance in patient care, particularly for patients requiring multiple scans. The results demonstrated that while both systems were effective, PCCT offered enhanced imaging and patient safety in neuroradiological evaluations.

Automatic segmentation of hemorrhagic transformation on follow-up non-contrast CT after acute ischemic stroke

Background

Hemorrhagic transformation (HT) following reperfusion therapies is a serious complication for patients with acute ischemic stroke. Segmentation and quantification of hemorrhage provides critical insights into patients' condition and aids in prognosis. This study aims to automatically segment hemorrhagic regions on follow-up non-contrast head CT (NCCT) for stroke patients treated with endovascular thrombectomy (EVT).

Methods

Patient data were collected from 10 stroke centers across two countries. We propose a semi-automated approach with adaptive thresholding methods, eliminating the need for extensive training data and reducing computational demands. We used Dice Similarity Coefficient (DSC) and Lin's Concordance Correlation Coefficient (Lin's CCC) to evaluate the performance of the algorithm.

Results

A total of 51 patients were included, with 28 Type 2 hemorrhagic infarction (HI2) cases and 23 parenchymal hematoma (PH) cases. The algorithm achieved a mean DSC of 0.66 ± 0.17. Notably, performance was superior for PH cases (mean DSC of 0.73 ± 0.14) compared to HI2 cases (mean DSC of 0.61 ± 0.18). Lin's CCC was 0.88 (95% CI 0.79-0.93), indicating a strong agreement between the algorithm's results and the ground truth. In addition, the algorithm demonstrated excellent processing time, with an average of 2.7 s for each patient case.

Conclusion

To our knowledge, this is the first study to perform automated segmentation of post-treatment hemorrhage for acute stroke patients and evaluate the performance based on the radiological severity of HT. This rapid and effective tool has the potential to assist with predicting prognosis in stroke patients with HT after EVT.

Medical malpractice and epidural hematomas: a retrospective analysis of 101 cases in the United States

Background

Neurosurgeons face particularly high rates of litigation compared to physicians in other fields. Malpractice claims are commonly seen after mismanagement of life-threatening medical emergencies, such as epidural haematomas. Due to the lack of legal analysis pertaining to this condition, the aim of this study is to identify risk factors associated with litigation in cases relating to the diagnosis and treatment of epidural haematomas.

Materials and methods

Westlaw Edge, an online database, was used to analyze malpractice cases related to epidural haematomas between 1986 and 2022. Information regarding plaintiff demographics, defendant specialty, reason for litigation, trial outcomes, and payouts for verdicts and settlements were recorded. Comparative analysis between cases that returned a jury verdict in favour of the plaintiff versus defendant was completed.

Results

A total of 101 cases were included in the analysis. Failure to diagnose was the most common reason for litigation (n = 64, 63.4%), followed by negligent care resulting in an epidural haematoma (n = 44, 43.6%). Spine surgery (n = 29, 28.7%), trauma (n = 28, 27.7%), and epidural injection/catheter/electrode placement (n = 21, 20.8%) were the primary causes of haematomas. Neurosurgeons (n = 18, 17.8%) and anesthesiologists (n = 17, 16.8%) were the two most common physician specialties cited as defendants. Most cases resulted in a jury verdict in favour of the defense (n = 54, 53.5%). For cases ending in plaintiff verdicts, the average payout was $3 621 590.45, while the average payment for settlements was $2 432 272.73.

Conclusion

Failure to diagnose epidural haematomas is the most common reason for malpractice litigation, with neurosurgeons and anesthesiologists being the most common physician specialties to be named as defendants. More than half of all cases returned a jury verdict in favour of the defense and, on average, settlements proved to be more cost-effective than plaintiff verdicts.

Day one postoperative MRI findings following electrode placement for deep brain stimulation: analysis of a large case series

Objective

This study sought to characterize postoperative day one MRI findings in deep brain stimulation (DBS) patients.

Methods

DBS patients were identified by CPT and had their reviewed by a trained neuroradiologist and neurosurgeon blinded to MR sequence and patient information. The radiographic abnormalities of interest were track microhemorrhage, pneumocephalus, hematomas, and edema, and the occurrence of these findings in compare the detection of these complications between T1/T2 gradient-echo (GRE) and T1/T2 fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) sequences was compared. The presence, size, and association of susceptibility artifact with other radiographic abnormalities was also described. Lastly, the association of multiple microelectrode cannula passes with each radiographic finding was evaluated. Ad-hoc investigation evaluated hemisphere-specific associations. Multiple logistic regression with Bonferroni correction (corrected p = 0.006) was used for all analysis.

Results

Out of 198 DBS patients reviewed, 115 (58%) patients showed entry microhemorrhage; 77 (39%) track microhemorrhage; 44 (22%) edema; 69 (35%) pneumocephalus; and 12 (6%) intracranial hematoma. T2 GRE was better for detecting microhemorrhage (OR = 14.82, p < 0.0001 for entry site and OR = 4.03, p < 0.0001 for track) and pneumocephalus (OR = 11.86, p < 0.0001), while T2 FLAIR was better at detecting edema (OR = 123.6, p < 0.0001). The relatively common findings of microhemorrhage and edema were best visualized by T2 GRE and T2 FLAIR sequences, respectively. More passes intraoperatively was associated with detection of ipsilateral track microhemorrhage (OR = 7.151, p < 0.0001 left; OR = 8.953, p < 0.0001 right). Susceptibility artifact surrounding electrodes possibly interfered with further detection of ipsilateral edema (OR = 4.323, p = 0.0025 left hemisphere only).

Discussion

Day one postoperative magnetic resonance imaging (MRI) for DBS patients can be used to detect numerous radiographic abnormalities not identifiable on a computed tomographic (CT) scan. For this cohort, multiple stimulating cannula passes intraoperatively was associated with increased microhemorrhage along the electrode track. Further studies should be performed to evaluate the clinical relevance of these observations.

Functional effects of haemoglobin can be rescued by haptoglobin in an in vitro model of subarachnoid haemorrhage

During subarachnoid haemorrhage, a blood clot forms in the subarachnoid space releasing extracellular haemoglobin (Hb), which causes oxidative damage and cell death in surrounding tissues. High rates of disability and cognitive decline in SAH survivors are attributed to loss of neurons and functional connections during secondary brain injury. Haptoglobin sequesters Hb for clearance, but this scavenging system is overwhelmed after a haemorrhage. Whilst exogenous haptoglobin application can attenuate cytotoxicity of Hb in vitro and in vivo, the functional effects of sub-lethal Hb concentrations on surviving neurons and whether cellular function can be protected with haptoglobin treatment remain unclear. Here we use cultured neurons to investigate neuronal health and function across a range of Hb concentrations to establish the thresholds for cellular damage and investigate synaptic function. Hb impairs ATP concentrations and cytoskeletal structure. At clinically relevant but sub-lethal Hb concentrations, we find that synaptic AMPAR-driven currents are reduced, accompanied by a reduction in GluA1 subunit expression. Haptoglobin co-application can prevent these deficits by scavenging free Hb to reduce it to sub-threshold concentrations and does not need to be present at stoichiometric amounts to achieve efficacy. Haptoglobin itself does not impair measures of neuronal health and function at any concentration tested. Our data highlight a role for Hb in modifying synaptic function in surviving neurons, which may link to impaired cognition or plasticity after SAH and support the development of haptoglobin as a therapy for subarachnoid haemorrhage.

Subacute Haemorrhage in the Seminal Vesicle as a Cause of Persistent Haematospermia: A Case Report

Haematospermia is a relatively uncommon condition that can be caused by a variety of factors, including infection, inflammation, trauma, and neoplastic disease. Bleeding from the seminal vesicle is considered to be a rare cause. We present a case of a 65-year-old man who had repeated episodes of haematospermia over the previous few years. Initial physical examination was unremarkable. Laboratory tests, including coagulation profile and prostate-specific antigen level, were within normal limits. A magnetic resonance imaging scan of his pelvis revealed a right seminal vesicle haemorrhage as the cause of his haematospermia. The patient was reassured and was managed conservatively.

B-Mode Ultrasound, a Reliable Tool for Monitoring Experimental Intracerebral Hemorrhage

Background: Magnetic resonance imaging (MRI) is currently used for the study of intracerebral hemorrhage (ICH) in animal models. However, ultrasound is an inexpensive, non-invasive and rapid technique that could facilitate the diagnosis and follow-up of ICH. This study aimed to evaluate the feasibility and reliability of B-mode ultrasound as an alternative tool for in vivo monitoring of ICH volume and brain structure displacement in an animal model.

Methods: A total of 31 male and female Sprague-Dawley rats were subjected to an ICH model using collagenase-IV in the striatum following stereotaxic references. The animals were randomly allocated into 3 groups: healthy (n = 10), sham (n = 10) and ICH (n = 11). B-mode ultrasound studies with a 13-MHz probe were performed pre-ICH and at 5 h, 48 h, 4 d and 1 mo post-ICH for the assessment of ICH volume and displacement of brain structures, considering the distance between the subarachnoid cisterns and the dura mater. The same variables were studied by MRI at 48 h and 1 mo post-ICH.

Results: Both imaging techniques showed excellent correlation in measuring ICH volume at 48 h (r = 0.905) and good at 1 mo (r = 0.656). An excellent correlation was also observed in the measured distance between the subarachnoid cisterns and the dura mater at 1 mo between B-mode ultrasound and MRI, on both the ipsilateral (r = 0.870) and contralateral (r = 0.906) sides of the lesion.

Conclusion: B-mode ultrasound imaging appears to be a reliable tool for in vivo assessment of ICH volume and displacement of brain structures in animal models.

Interrelation between Spectral Online Monitoring and Postoperative T1-Weighted MRI in Interstitial Photodynamic Therapy of Malignant Gliomas

Simple Summary

Treatment monitoring is highly important for the delivery and control of brain tumor therapy. For interstitial photodynamic therapy (iPDT), an intraoperative spectral online monitoring (SOM) setup was established in former studies to monitor photosensitizer fluorescence and treatment light transmission during therapy. In this work, data from patients treated with iPDT as the initial treatment for newly diagnosed glioblastoma (n = 11) were retrospectively analyzed. Observed changes in treatment light transmission were assessed, and changes in optical tissue absorption were calculated out of these. In addition, magnetic resonance imaging (MRI) data were recorded within 48 h after therapy and showed intrinsic T1 hyperintensity in the treated area in non-contrast-enhanced T1-weighted sequences. A 3D co-registration of intrinsic T1 hyperintensity lesions and the light transmission zones between cylindrical diffuser fiber pairs showed that reduction in treatment light transmission corresponding to increased light absorption had a spatial correlation with post-therapeutic intrinsic T1 hyperintensity (p ≤ 0.003).

Abstract

In a former study, interstitial photodynamic therapy (iPDT) was performed on patients suffering from newly diagnosed glioblastoma (n = 11; 8/3 male/female; median age: 68, range: 40–76). The procedure includes the application of 5-ALA to selectively metabolize protoporphyrin IX (PpIX) in tumor cells and illumination utilizing interstitially positioned optical cylindrical diffuser fibers (CDF) (2–10 CDFs, 2–3 cm diffusor length, 200 mW/cm, 635 nm, 60 min irradiation). Intraoperative spectral online monitoring (SOM) was employed to monitor treatment light transmission and PpIX fluorescence during iPDT. MRI was used for treatment planning and outcome assessment. Case-dependent observations included intraoperative reduction of treatment light transmission and local intrinsic T1 hyperintensity in non-contrast-enhanced T1-weighted MRI acquired within one day after iPDT. Intrinsic T1 hyperintensity was observed and found to be associated with the treatment volume, which indicates the presence of methemoglobin, possibly induced by iPDT. Based on SOM data, the optical absorption coefficient and its change during iPDT were estimated for the target tissue volumes interjacent between evaluable CDF-pairs at the treatment wavelength of 635 nm. By spatial comparison and statistical analysis, it was found that observed increases of the absorption coefficient during iPDT were larger in or near regions of intrinsic T1 hyperintensity (p = 0.003). In cases where PpIX-fluorescence was undetectable before iPDT, the increase in optical absorption and intrinsic T1 hyperintensity tended to be less. The observations are consistent with in vitro experiments and indicate PDT-induced deoxygenation of hemoglobin and methemoglobin formation. Further investigations are needed to provide more data on the time course of the observed changes, thus paving the way for optimized iPDT irradiation protocols.

Portable, bedside, low-field magnetic resonance imaging for evaluation of intracerebral hemorrhage

Radiological examination of the brain is a critical determinant of stroke care pathways. Accessible neuroimaging is essential to detect the presence of intracerebral hemorrhage (ICH). Conventional magnetic resonance imaging (MRI) operates at high magnetic field strength (1.5-3 T), which requires an access-controlled environment, rendering MRI often inaccessible. We demonstrate the use of a low-field MRI (0.064 T) for ICH evaluation. Patients were imaged using conventional neuroimaging (non-contrast computerized tomography (CT) or 1.5/3 T MRI) and portable MRI (pMRI) at Yale New Haven Hospital from July 2018 to November 2020. Two board-certified neuroradiologists evaluated a total of 144 pMRI examinations (56 ICH, 48 acute ischemic stroke, 40 healthy controls) and one ICH imaging core lab researcher reviewed the cases of disagreement. Raters correctly detected ICH in 45 of 56 cases (80.4% sensitivity, 95%CI: [0.68-0.90]). Blood-negative cases were correctly identified in 85 of 88 cases (96.6% specificity, 95%CI: [0.90-0.99]). Manually segmented hematoma volumes and ABC/2 estimated volumes on pMRI correlate with conventional imaging volumes (ICC = 0.955, p = 1.69e-30 and ICC = 0.875, p = 1.66e-8, respectively). Hematoma volumes measured on pMRI correlate with NIH stroke scale (NIHSS) and clinical outcome (mRS) at discharge for manual and ABC/2 volumes. Low-field pMRI may be useful in bringing advanced MRI technology to resource-limited settings.

Towards precision nanomedicine for cerebrovascular diseases with emphasis on Cerebral Cavernous Malformation (CCM)

Introduction: Cerebrovascular diseases encompass various disorders of the brain vasculature, such as ischemic/hemorrhagic strokes, aneurysms, and vascular malformations, also affecting the central nervous system leading to a large variety of transient or permanent neurological disorders. They represent major causes of mortality and long-term disability worldwide, and some of them can be inherited, including Cerebral Cavernous Malformation (CCM), an autosomal dominant cerebrovascular disease linked to mutations in CCM1/KRIT1, CCM2, or CCM3/PDCD10 genes.Areas covered: Besides marked clinical and etiological heterogeneity, some commonalities are emerging among distinct cerebrovascular diseases, including key pathogenetic roles of oxidative stress and inflammation, which are increasingly recognized as major disease hallmarks and therapeutic targets. This review provides a comprehensive overview of the different clinical features and common pathogenetic determinants of cerebrovascular diseases, highlighting major challenges, including the pressing need for new diagnostic and therapeutic strategies, and focusing on emerging innovative features and promising benefits of nanomedicine strategies for early detection and targeted treatment of such diseases.Expert opinion: Specifically, we describe and discuss the multiple physico-chemical features and unique biological advantages of nanosystems, including nanodiagnostics, nanotherapeutics, and nanotheranostics, that may help improving diagnosis and treatment of cerebrovascular diseases and neurological comorbidities, with an emphasis on CCM disease.

Comparison of T2*GRE and DSC-PWI for hemorrhage detection in acute ischemic stroke patients: Pooled analysis of the EPITHET, DEFUSE 2, and SENSE 3 stroke studies

AIMS

The objective of this study was to compare the diagnostic performance of the baseline pre-contrast images of dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) with conventional T2*gradient recalled echo (GRE) imaging for detection of hemorrhage in acute ischemic stroke patients.

MATERIAL AND METHODS

T2*GRE and DSC-PWI from 393 magnetic resonance imaging scans from 221 patients enrolled in three prospective stroke studies were independently evaluated by two readers blinded to clinical and other imaging data. Agreement between T2*GRE and DSC-PWI for the presence of hemorrhage, and acute hemorrhagic transformation, was assessed using the kappa statistic. Inter-reader agreement was also assessed using the kappa statistic.

RESULTS

Agreement between the baseline images of DSC-PWI and T2*GRE regarding the presence of hemorrhage was almost perfect (k_reader 1 : 0.90, 95% confidence interval 0.86-0.95 and k_reader 2 : 0.91, 95% confidence interval 0.87-0.96). Agreement between the sequences was still higher for detection of acute hemorrhagic transformation (k_reader 1 : 0.94, 95% confidence interval 0.91-0.98 and k_reader 2 : 0.95, 95% confidence interval 0.92-0.98). Inter-reader agreement for detection of hemorrhage was also almost perfect for both T2*GRE (k: 0.95, 95% confidence interval 0.91-0.98) and DSC-PWI (k: 0.96, 95% confidence interval 0.93-0.99). Acute hemorrhagic transformation detected on T2*GRE was missed on DSC-PWI by one or both readers in 5/393 (1.3%) scans.

CONCLUSION

The almost perfect statistical agreement between DSC-PWI and conventional T2*GRE suggests that DSC-PWI is sufficient for hemorrhage screening prior to thrombolysis in stroke patients. T2*GRE can therefore be omitted when DSC-PWI is included, thereby shortening the acute ischemic stroke magnetic resonance imaging protocol and expediting treatment. Trial registration: ClinicalTrials.gov Identifier: NCT02586415.

Galectins in the Pathogenesis of Cerebrovascular Accidents: An Overview

Due to limitations of neuroimaging, such as the isodense appearance of blood to neuronal tissue in subacute hemorrhagic stroke, a body of studies have been performed to evaluate candidate biomarkers which may aid in accurate determination of cerebrovascular accident type. Beyond aiding in the delineation of stroke cause, biomarkers could also confer useful prognostic information to help clinicians plan use of resources. One of the candidate biomarkers studied for detection of cerebrovascular accident (CVA) includes a class of proteins called galectins. Galectins bind β-galactoside through a highly conserved carbohydrate recognition domain, endowing an ability to interact with carbohydrate moieties on glycoproteins, some of which are relevant to CVA response. Furthermore, galectins-1, -2, -3, -9, and -12 are expressed in tissues relevant to CVA, and some exhibit characteristics (eg, extracellular secretion) that could render feasible their detection in serum. Galectins-1 and -3 appear to have the largest amounts of preclinical evidence, consistently demonstrating increased activity and expression levels during CVA. However, a lack of standardization of biochemical assays across cohort studies limits further translation of these basic science studies. This review aims to increase awareness of the biochemical roles of galectins in CVA, while also highlighting challenges and remaining questions preventing the translation of basic science observations into a clinically useful test.

Differentiation of Hemorrhage from Iodine Using Spectral Detector CT: A Phantom Study

BACKGROUND AND PURPOSE

Conventional CT often cannot distinguish hemorrhage from iodine extravasation following reperfusion therapy for acute ischemic stroke. We investigated the potential of spectral detector CT in differentiating these lesions.

MATERIALS AND METHODS

Centrifuged blood with increasing hematocrit (5%-85%) was used to model hemorrhage. Pure blood, blood-iodine mixtures (75/25, 50/50, and 25/75 ratios), and iodine solutions (0-14 mg I/mL) were scanned in a phantom with attenuation ranging from 12 to 75 HU on conventional imaging. Conventional and virtual noncontrast attenuation was compared and investigated for correlation with calculation of relative virtual noncontrast attenuation. Values for all investigated categories were compared using the Mann-Whitney U test. Sensitivity and specificity of virtual noncontrast, relative virtual noncontrast, conventional CT attenuation, and iodine quantification for hemorrhage detection were determined with receiver operating characteristic analysis.

RESULTS

Conventional image attenuation was not significantly different among all samples containing blood (P > .05), while virtual noncontrast attenuation showed a significant decrease with a decreasing blood component (P < .01) in all blood-iodine mixtures. Relative virtual noncontrast values were significantly different among all investigated categories (P < .01), with correct hemorrhagic component size estimation for all categories within a 95% confidence interval. Areas under the curve for hemorrhage detection were 0.97, 0.87, 0.29, and 0.16 for virtual noncontrast, relative virtual noncontrast, conventional CT attenuation, and iodine quantification, respectively. A ≥10-HU virtual noncontrast, ≥20-HU virtual noncontrast, ≥40% relative virtual noncontrast, and combined ≥10-HU virtual noncontrast and ≥40% relative virtual noncontrast attenuation threshold had a sensitivity/specificity for detecting hemorrhage of 100%/23%, 89%/95%, 100%/82%, and 100%/100%, respectively.

CONCLUSIONS

Spectral detector CT can accurately differentiate blood from iodinated contrast in a phantom setting.

Intracranial hemorrhage alters scalp potential distribution in bioimpedance cerebral monitoring: Preliminary results from FEM simulation on a realistic head model and human subjects

PURPOSE

Current diagnostic neuroimaging for detection of intracranial hemorrhage (ICH) is limited to fixed scanners requiring patient transport and extensive infrastructure support. ICH diagnosis would therefore benefit from a portable diagnostic technology, such as electrical bioimpedance (EBI). Through simulations and patient observation, the authors assessed the influence of unilateral ICH hematomas on quasisymmetric scalp potential distributions in order to establish the feasibility of EBI technology as a potential tool for early diagnosis.

METHODS

Finite element method (FEM) simulations and experimental left-right hemispheric scalp potential differences of healthy and damaged brains were compared with respect to the asymmetry caused by ICH lesions on quasisymmetric scalp potential distributions. In numerical simulations, this asymmetry was measured at 25 kHz and visualized on the scalp as the normalized potential difference between the healthy and ICH damaged models. Proof-of-concept simulations were extended in a pilot study of experimental scalp potential measurements recorded between 0 and 50 kHz with the authors' custom-made bioimpedance spectrometer. Mean left-right scalp potential differences recorded from the frontal, central, and parietal brain regions of ten healthy control and six patients suffering from acute/subacute ICH were compared. The observed differences were measured at the 5% level of significance using the two-sample Welch t-test.

RESULTS

The 3D-anatomically accurate FEM simulations showed that the normalized scalp potential difference between the damaged and healthy brain models is zero everywhere on the head surface, except in the vicinity of the lesion, where it can vary up to 5%. The authors' preliminary experimental results also confirmed that the left-right scalp potential difference in patients with ICH (e.g., 64 mV) is significantly larger than in healthy subjects (e.g., 20.8 mV; P < 0.05).

CONCLUSIONS

Realistic, proof-of-concept simulations confirmed that ICH affects quasisymmetric scalp potential distributions. Pilot clinical observations with the authors' custom-made bioimpedance spectrometer also showed higher left-right potential differences in the presence of ICH, similar to those of their simulations, that may help to distinguish healthy subjects from ICH patients. Although these pilot clinical observations are in agreement with the computer simulations, the small sample size of this study lacks statistical power to exclude the influence of other possible confounders such as age, sex, and electrode positioning. The agreement with previously published simulation-based and clinical results, however, suggests that EBI technology may be potentially useful for ICH detection.

Seven patients diagnosed as intracranial hemorrhage combined with intracranial tumor: case description and literature review

In the present study, 7 patients with brain hemorrhage combined with intracranial tumor were investigated for about 3 years. Furthermore, the previous reports related with such cases were also reviewed. In all of these patients, hemorrhage was a main characteristic of the diagnosed neoplasm. The clinical data were identified by computed tomography (CT) scanning in the present study. CT scanning results demonstrated that there was a neoplastic core with high or low density and multifocal clots generally at the borders of the tumors. Increase of tumor tissues with intravenous injection of approximate 70% hypaque was analyzed in all the 7 patients with brain hemorrhage. The parts that were increased showed peripheral distributions corresponding to the hemorrhage sites. In conclusion, the intracranial brain hemorrhage related with the several types of tumors, including hemangiopericytoma, metastatic carcinomas, oligodendroglioma, and glioblastoma multiforme, which may be helpful to these patients.

The active extravasation of contrast (spot sign) depicted on multidetector computed tomography angiography might predict structural vascular etiology and mortality in secondary intracranial hemorrhage

OBJECTIVE

Intracerebral hemorrhage (ICH) occurs in 10% to 15% of all strokes and is accompanied by high rates of mortality, disability, and neurological sequelae. Our aim was to assess the presence and prognostic implications of the active extravasation of contrast within the hemorrhage (spot sign) in a series of patients with secondary ICH.

METHODS

We analysed 59 subjects who arrived at a tertiary hospital with secondary ICH and a brain parenchyma hemorrhage greater than 2.0 cm in any axis.

RESULTS

Spot sign was observed in 11 subjects, including 8 patients with saccular aneurysm, 1 with arteriovenous malformation, 1 with coagulation disorder and 1 with venous sinus thrombosis. A 37.5% mortality rate was documented in the spot sign-negative group, whereas the presence of this imaging finding was followed by an 81.8% in-hospital mortality rate.

CONCLUSIONS

Spot sign was correlated with vascular etiology and was a predictor of mortality in our series of patients.

Simultaneous detection and separation of hyperacute intracerebral hemorrhage and cerebral ischemia using amide proton transfer MRI

PURPOSE

To explore the capability of amide proton transfer (APT) imaging in the detection of hemorrhagic and ischemic strokes using preclinical rat models.

METHODS

The rat intracerebral hemorrhage (ICH) model (n = 10) was induced by injecting bacterial collagenase VII-S into the caudate nucleus, and the permanent ischemic stroke model (n = 10) was induced by using a 4-0 nylon suture to occlude the origin of the middle cerebral artery. APT-weighted (APTw) MRI was acquired on a 4.7T animal imager and quantified using the magnetization transfer-ratio asymmetry at 3.5 ppm from water.

RESULTS

There was a consistently high APTw MRI signal in hyperacute ICH during the initial 12 h after injection of collagenase compared with the contralateral brain tissue. When hemorrhagic and ischemic stroke were compared, hyperacute ICH and cerebral ischemia demonstrated opposite APTw MRI contrasts-namely, hyperintense versus hypointense compared with contralateral brain tissue, respectively. There was a stark contrast in APTw signal intensity between these two lesions.

CONCLUSION

APT-MRI could accurately detect hyperacute ICH and distinctly differentiate hyperacute ICH from cerebral ischemia, thus opening up the possibility of introducing to the clinic a single MRI scan for the simultaneous visualization and separation of hemorrhagic and ischemic strokes at the hyperacute stage. Magn Reson Med 74:42-50, 2015. © 2014 Wiley Periodicals, Inc.

Temporal evolution of intraparenchymal hyperdensity after intra-arterial therapy in patients with ischemic stroke: optimal discrimination between hemorrhage and iodinated contrast

PURPOSE

CT hyperattenuation arising from iodinated contrast has a different temporal evolution than that arising due to hemorrhage. This paper presents a method for optimal discrimination between hemorrhage and iodinated contrast in a postintervention CT in stroke patients.

METHODS

We analyzed the brain computed tomography (CT) scans of consecutive patients with intraparenchymal hyperattenuation due to hemorrhage (n=41), those due to iodinated contrast alone (n=24), and those due to contrast mixed with hemorrhage after reperfusion therapy (n=14) in stroke patients. The difference between the maximum enhancement in hyperattenuation in the affected area and the corresponding contralateral area, dubbed Relative Maximum Enhancement (RME), was tracked over time. We fitted regression models to the RME changes due to hemorrhage and contrast to describe their temporal decay, and then derived the optimal discriminant curve that distinguishes the two. A computer algorithm coregistered the baseline and follow-up CT scans and performed pixel-by-pixel comparison to determine hemorrhage and iodinated contrast based on the RME changes with respect to the discriminant curve.

RESULTS

For both hemorrhage (k= -0.004, R (2) =0.7) and iodinated contrast (k= -0.064, R (2)  =0.9), the temporal evolution of RMEs were best fitted by exponential decay curves, with respective half-lives of 192.3 and 10.7 h. An exponential decay model (k= -0.026) for optimal discrimination of hemorrhage vs. contrast was fitted. The computer algorithm implementing this model was successful in predicting the presence of hemorrhage in a hyperdense lesion with sensitivity =93% and specificity =91%.

CONCLUSION

Intraparenchymal hemorrhage and contrast have markedly different decay half-lives that can be used to assess hemorrhage in a hyperdense lesion on a CT scan after intra-arterial therapy.

The role of advanced neuroimaging in intracerebral hemorrhage

In this report, the authors sought to summarize existing literature to provide an overview of the currently available techniques and to critically assess the evidence for or against their application in intracerebral hemorrhage (ICH) for management, prognostication, and research. Functional imaging in ICH represents a potential major step forward in the ability of physicians to assess patients suffering from this devastating illness due to the advantages over standing imaging modalities focused on general tissue structure alone, but its use is highly controversial due to the relative paucity of literature and the lack of consolidation of the predominantly small data sets that are currently in existence. Current data support that diffusion tensor imaging and tractography, diffusion-perfusion weighted MRI techniques, and functional MRI all possess major potential in the areas of highlighting motor deficits, motor recovery, and network reorganization. Novel clinical studies designed to objectively assess the value of each of these modalities on a wider scale in conjunction with other methods of investigation and management will allow for their rapid incorporation into standard practice.

Interobserver agreement and diagnostic accuracy of brain magnetic resonance imaging in dogs

OBJECTIVE

To evaluate interobserver agreement and diagnostic accuracy of brain MRI in dogs.

DESIGN

Evaluation study.

ANIMALS

44 dogs.

PROCEDURES

5 board-certified veterinary radiologists with variable MRI experience interpreted transverse T2-weighted (T2w), T2w fluid-attenuated inversion recovery (FLAIR), and T1-weighted-FLAIR; transverse, sagittal, and dorsal T2w; and T1-weighted-FLAIR postcontrast brain sequences (1.5 T). Several imaging parameters were scored, including the following: lesion (present or absent), lesion characteristics (axial localization, mass effect, edema, hemorrhage, and cavitation), contrast enhancement characteristics, and most likely diagnosis (normal, neoplastic, inflammatory, vascular, metabolic or toxic, or other). Magnetic resonance imaging diagnoses were determined initially without patient information and then repeated, providing history and signalment. For all cases and readers, MRI diagnoses were compared with final diagnoses established with results from histologic examination (when available) or with other pertinent clinical data (CSF analysis, clinical response to treatment, or MRI follow-up). Magnetic resonance scores were compared between examiners with κ statistics.

RESULTS

Reading agreement was substantial to almost perfect (0.64 < κ < 0.86) when identifying a brain lesion on MRI; fair to moderate (0.14 < κ < 0.60) when interpreting hemorrhage, edema, and pattern of contrast enhancement; fair to substantial (0.22 < κ < 0.74) for dural tail sign and categorization of margins of enhancement; and moderate to substantial (0.40 < κ < 0.78) for axial localization, presence of mass effect, cavitation, intensity, and distribution of enhancement. Interobserver agreement was moderate to substantial for categories of diagnosis (0.56 < κ < 0.69), and agreement with the final diagnosis was substantial regardless of whether patient information was (0.65 < κ < 0.76) or was not (0.65 < κ < 0.68) provided.

CONCLUSIONS AND CLINICAL RELEVANCE

The present study found that whereas some MRI features such as edema and hemorrhage were interpreted less consistently, radiologists were reasonably constant and accurate when providing diagnoses.

Meningeal osteochondroma simulating meningioma with metaplastic change: a rare golf-ball-like lesion of non-meningothelial mesenchymal origin

Non-meningothelial mesenchymal tumors of the central nervous system (CNS), including those originating from the meninges, histologically correspond to tumors of soft tissue or bone. These individual entities arising from the meninges are rare, and probably have their origin in the multipotent primitive mesenchymal stem cells of the dura. Though it is a common bone tumor, the meningeal origin of osteochondroma has only very rarely been reported. We describe a case of a 35-year-old female with a well-demarcated, golf-ball-like osteochondroma of meningeal origin which was enucleated en bloc on craniotomy. Such a lesion can resemble a meningioma that exhibits metaplastic (osseous) change on imaging. However, provided that there is clinico-radiological awareness of such tumors, magnetic resonance imaging (MRI) can guide the way to this rare differential diagnosis, as it reflects the pathologic appearance of osteochondroma and allows the thickness of the cartilage cap to be estimated in order to check for rare malignant change. Complete excision along with the cartilage cap usually offers a favorable prognosis without recurrence.

Neuroimaging for the anesthesiologist

This article provides an overview of neuroimaging modalities of particular interest to the anesthesiologist caring for neurosurgical patients. Imaging characteristics of neuropathologies and considerations for anesthetic management of diagnostic procedures are discussed.