Cerebrovascular Events After Continuous-Flow Left Ventricular Assist Devices.

BACKGROUND: Cerebrovascular events (CVE) are among the most common and serious complications after implantation of continuous-flow left ventricular assist devices (CF-LVAD). We studied the incidence, subtypes, anatomical distribution, and pre- and post-implantation risk factors of CVEs as well as the effect of CVEs on outcomes after CF-LVAD implantation at our institution. METHODS: Retrospective analysis of clinical and neuroimaging data of 372 patients with CF-LVAD between May 2005 and December 2013 using standard statistical methods. RESULTS: CVEs occurred in 71 patients (19%), consisting of 35 ischemic (49%), 26 hemorrhagic (37%), and 10 ischemic+hemorrhagic (14%) events. History of coronary artery disease and female gender was associated with higher odds of ischemic CVE (OR 2.84 and 2.5, respectively), and diabetes mellitus was associated with higher odds of hemorrhagic CVE (OR 3.12). While we found a higher rate of ischemic CVEs in patients not taking any antithrombotic medications, no difference was found between patients with ischemic and hemorrhagic CVEs. Occurrence of CVEs was associated with increased mortality (HR 1.62). Heart transplantation was associated with improved survival (HR 0.02). In patients without heart transplantation, occurrence of CVE was associated with decreased survival. CONCLUSIONS: LVADs are associated with high rates of CVE, increased mortality, and lower rates of heart transplantation. Further investigations to identify the optimal primary and secondary stroke prevention measures in post-LVAD patients are warranted.

Presurgical brain mapping of the language network in patients with brain tumors using resting-state fMRI: Comparison with task fMRI.

PURPOSE: To compare language networks derived from resting-state fMRI (rs-fMRI) with task-fMRI in patients with brain tumors and investigate variables that affect rs-fMRI vs task-fMRI concordance. MATERIALS AND METHODS: Independent component analysis (ICA) of rs-fMRI was performed with 20, 30, 40, and 50 target components (ICA20 to ICA50) and language networks identified for patients presenting for presurgical fMRI mapping between 1/1/2009 and 7/1/2015. 49 patients were analyzed fulfilling criteria for presence of brain tumors, no prior brain surgery, and adequate task-fMRI performance. Rs-vs-task-fMRI concordance was measured using Dice coefficients across varying fMRI thresholds before and after noise removal. Multi-thresholded Dice coefficient volume under the surface (DiceVUS) and maximum Dice coefficient (MaxDice) were calculated. One-way Analysis of Variance (ANOVA) was performed to determine significance of DiceVUS and MaxDice between the four ICA order groups. Age, Sex, Handedness, Tumor Side, Tumor Size, WHO Grade, number of scrubbed volumes, image intensity root mean square (iRMS), and mean framewise displacement (FD) were used as predictors for VUS in a linear regression. RESULTS: Artificial elevation of rs-fMRI vs task-fMRI concordance is seen at low thresholds due to noise. Noise-removed group-mean DiceVUS and MaxDice improved as ICA order increased, however ANOVA demonstrated no statistically significant difference between the four groups. Linear regression demonstrated an association between iRMS and DiceVUS for ICA30-50, and iRMS and MaxDice for ICA50. CONCLUSION: Overall there is moderate group level rs-vs-task fMRI language network concordance, however substantial subject-level variability exists; iRMS may be used to determine reliability of rs-fMRI derived language networks.

Case 236: Middle Interhemispheric Variant of Holoprosencephaly.

History A 13-year-old girl presented for evaluation and further management of spastic diplegia cerebral palsy. Absence of the corpus callosum was noted at screening prenatal head ultrasonography. She was born at full term via spontaneous vaginal delivery. Physical examination revealed decreased axial muscle tone and increased muscle tone in her extremities; the latter was more severe. She was nonambulatory. No midline craniofacial anomaly was seen. She had dysarthria but was able to speak in full sentences. She was in sixth grade with an individualized education program. She had mild behavioral problems, such as "acting out" in school. Brain magnetic resonance (MR) imaging, including three-dimensional T1- and T2-weighted sequences, was performed without intravenous administration of contrast material to evaluate the brain.

Neurovascular uncoupling in resting state fMRI demonstrated in patients with primary brain gliomas.

BACKGROUND: To demonstrate that the problem of brain tumor-related neurovascular uncoupling (NVU) is a significant issue with respect to resting state blood oxygen level dependent (BOLD) functional MRI (rsfMRI) similar to task-based BOLD fMRI, in which signal detectability can be compromised by breakdown of normal neurovascular coupling. METHODS: We evaluated seven de novo brain tumor patients who underwent resting state fMRI as part of comprehensive clinical fMRI exams at 3 Tesla. For each of the seven patients who demonstrated evidence of NVU on task-based motor fMRI, we performed both an independent component analysis (ICA) and an atlas-based parcellation-based seed correlation analysis (SCA) of the resting state fMRI data. For each patient, ipsilesional (IL) and contralesional (CL) regions of interest (ROIs) comprising primary motor and somatosensory cortices were used to evaluate BOLD signal changes on Z score maps derived from both ICA and SCA analysis for evidence of NVU. A subsequent two-tailed t-test was performed to determine whether statistically significant differences between the two sides were present that were consistent with NVU. RESULTS: In seven patients, overall decreased BOLD signal (based on suprathreshold voxels in ICA and SCA-derived Z-score maps) was noted in IL compared with CL ROIs (P < 0.01), consistent with NVU. CONCLUSION: We have demonstrated that NVU can result in false negative BOLD signal changes on rsfMRI comparable to previously published findings on standard motor task-based fMRI.

Imaging of cosmetic plastic procedures and implants in the body and their potential complications.

OBJECTIVE: Cosmetic plastic surgery procedures, as well as implants, are increasingly being performed. These implants are often encountered on routine imaging examinations, and radiologists are often asked to evaluate for complications or evidence of failure. Pectoral augmentation, gluteal augmentation, body lift and abdominoplasty, and penile and testicular prostheses are reviewed in this article. CONCLUSION: The typical appearance of common cosmetic implants and cosmetic techniques used in the human body is presented, along with the imaging spectrum of their potential complications.

Pediatric cardiac tumors: clinical and imaging features.

Cardiac tumors in children are rare, are more commonly benign, and differ in types when compared with those in adults. Rhabdomyoma, teratoma, and fibroma are the most common cardiac tumors in fetuses and neonates. In infants and children, the most common cardiac tumors are rhabdomyoma and fibroma, which are benign primary cardiac tumors, whereas in adults, thrombus is the most common cardiac mass and myxoma is the most common primary cardiac tumor. Sarcomas are the most common primary malignant cardiac tumors in both children and adults. Metastatic cardiac tumors are less common in children than in adults and include sarcoma, lymphoma, testicular cancer, and Wilms tumor. Patients with cardiac tumors can be asymptomatic or may present with murmur, arrhythmia, heart failure, or sudden death. Echocardiography is the primary modality for initial evaluation of symptomatic patients. Cardiac magnetic resonance imaging provides further characterization of cardiac masses and tumors for diagnostic purposes and can be used to assess cardiac and extracardiac involvement for treatment planning. Treatment varies from conservative management or surgical resection to transplantation, depending on the diagnosis and the patient's symptoms. Rhabdomyoma typically regresses spontaneously during early childhood and does not require surgical intervention if asymptomatic. However, fibroma is generally resected because it does not regress. An understanding of the types of cardiac tumors that occur in infants and children, their clinical implications and associations, and their imaging appearances will facilitate patient management.

The ASNR International Collaborations Committee: Cultivating a Global Learning Community.

The American Society of Neuroradiology has expanded its global presence, driven by the efforts of the International Collaborations Committee. This committee is actively involved in training radiologists and fostering collaborations worldwide in the fields of education, research, and community service. This article explores key initiatives of the committee, such as the Anne G. Osborn ASNR International Outreach Professor Program, the International Imaging Series, and Virtual Reading Rooms. Additionally, we provide insight into recent developments related to the pandemic and outline future opportunities.

The Current State of Functional MR Imaging for Trauma Prognostication.

In this review, we discuss the basics of functional MRI (fMRI) techniques including task-based and resting state fMRI, and overview the major findings in patients with traumatic brain injury. We summarize the studies that have longitudinally evaluated the changes in brain connectivity and task-related activation in trauma patients during different phases of trauma. We discuss how these data may potentially be used for prognostication, treatment planning, or monitoring and management of trauma patients.

Equity, diversity & inclusion in academic radiology: An elusive dream.

BACKGROUND: Disparities in sex and race/ethnicity continue to persist in the academic radiology. This study addresses the sex/racial underrepresentation and evolution in the academic radiology. PURPOSE: To evaluate academic radiology temporal trends disparities by analyzing sex and race/ethnicity diversity in academic degree and tenure status. MATERIALS AND METHODS: A retrospective cross-sectional analysis conducted using American Association of Medical College database between 2007 and 2018. Trends in academic degree, tenure status, race/ethnicity, and sex assessed with linear regression analysis and Poisson regression model for annual percent change with statistical significance of p < 0.05. RESULTS: Out of 107,213 radiologists 72%, n = 76,893 males and 64%, n = 68,738 white faculty with 1277 males and 872 females. White MD-degree radiologists constitute 67.2%, Asian (20.9%), Black (2.5%), Hispanic (3.2%), multiple (3.4%), unknown (1.8%) and "other" (1%) races with a similar PhD/other doctoral and dual-degree. White faculty recruitment trend (n2007 = 955, n2018 = 703) and representation (-0.82% per year; 95% CI, -1.00 to -0.63; p < 0.0001) decreased, while Asian URM decreased respectively (n2007 = 152, n2018 = 205) (0.68% per year; 95% CI, 0.58 to 0.77; p < 0.0001). Females were underrepresented in all categories. CONCLUSION: URM and females are underrepresented in academic radiology. Academic degree types and tenure track may contribute to White and male academic radiologists overrepresentation.

Cerebral venous sinus thrombosis associated with vaccine-induced thrombotic thrombocytopenia.

Thrombosis-thrombocytopenia syndrome and cerebral venous sinus thrombosis have been rarely reported in patients who have received severe acute respiratory syndrome coronavirus 2 adenoviral vector vaccines. Awareness of this potential adverse effect, recognizing early clinical symptoms and subtle signs of cerebral venous sinus thrombosis on head computed tomography and brain magnetic resonance imaging, appropriate vascular imaging, and unique treatment for this condition is critical. This is a report of a case of vaccine-induced thrombotic thrombocytopenia and associated cerebral venous sinus thrombosis with emphasis on imaging and clinical course.

Demographic Reporting in Publicly Available Chest Radiograph Data Sets: Opportunities for Mitigating Sex and Racial Disparities in Deep Learning Models.

OBJECTIVE: Data sets with demographic imbalances can introduce bias in deep learning models and potentially amplify existing health disparities. We evaluated the reporting of demographics and potential biases in publicly available chest radiograph (CXR) data sets. METHODS: We reviewed publicly available CXR data sets available on February 1, 2021, with >100 CXRs and performed a thorough search of various repositories, including Radiopaedia and Kaggle. For each data set, we recorded the total number of images and whether the data set reported demographic variables (age, race or ethnicity, sex, insurance status) in aggregate and on an image-level basis. RESULTS: Twenty-three CXR data sets were included (range, 105-371,858 images). Most data sets reported demographics in some form (19 of 23; 82.6%) and on an image level (17 of 23; 73.9%). The majority reported age (19 of 23; 82.6%) and sex (18 of 23; 78.2%), but a minority reported race or ethnicity (2 of 23; 8.7%) and insurance status (1 of 23; 4.3%). Of the 13 data sets with sex distribution readily available, the average breakdown was 55.2% male subjects, ranging from 47.8% to 69.7% male representation. Of these, 8 (61.5%) overrepresented male subjects and 5 (38.5%) overrepresented female subjects. DISCUSSION: Although most publicly available CXR data sets report age and sex on an image-basis level, few report race or ethnicity and insurance status. Furthermore, these data sets frequently underrepresent one of the sexes, more frequently the female sex. We recommend that data sets report standard demographic variables, and when possible, balance demographic representation to mitigate bias. Furthermore, for researchers using these data sets, we recommend that attention be paid to balancing demographic labels in addition to disease labels, as well as developing training methods that can account for these imbalances.

A comparison of economic demand and conditioned-cued reinstatement of methamphetamine-seeking or food-seeking in rats.

This study examined whether continued access to methamphetamine or food reinforcement changed economic demand for both. The relationship between demand elasticity and cue-induced reinstatement was also determined. Male Long-Evans rats were lever pressed under increasing fixed-ratio requirements for either food pellets or methamphetamine (20 µg/50 µl infusion). For two groups, demand curves were obtained before and after continued access (12 days, 2-h sessions) to the reinforcer under a fixed-ratio 3 schedule. A third group was given continued access to methamphetamine between determinations of food demand and a fourth group abstained from methamphetamine between determinations. All groups underwent extinction sessions, followed by a cue-induced reinstatement test. Although food demand was less elastic than methamphetamine demand, continued access to methamphetamine shifted the methamphetamine demand curve upward and the food demand curve downward. In some rats, methamphetamine demand also became less elastic. Continued access to food had no effect on food demand. Reinstatement was higher after continued access to methamphetamine relative to food. For methamphetamine, elasticity and reinstatement measures were correlated. Continued access to methamphetamine, but not food, alters demand in ways suggestive of methamphetamine accruing reinforcing strength. Demand elasticity thus provides a useful measure of abuse liability that may predict future relapse to renewed drug-seeking and drug use.

Melatonin enhances the anticonvulsant and proconvulsant effects of morphine in mice: role for nitric oxide signaling pathway.

Melatonin has different interactions with opioids including enhancing their analgesic effect and reversal of opioid tolerance and dependence. Opioids are known to exert dose-dependent anti- and proconvulsant effects in different experimental seizure paradigms. This study investigated the effect of melatonin on biphasic modulation of seizure susceptibility by morphine, in mouse model of pentylenetetrazole (PTZ)-induced clonic seizures. We further investigated the involvement of the nitric oxidergic pathway in this interaction, using a nitric oxide synthase inhibitor, NG-nitro-L-arginine-methyl-ester (L-NAME). Melatonin exerted anticonvulsant effect with doses as high as 40-80 mg/kg, but with a dose far bellow that amount (10 mg/kg), it potentiated both the anticonvulsant and proconvulsant effects of morphine on the PTZ-induced clonic seizures. Possible pharmacokinetic interaction of melatonin and morphine cannot be ruled out in the enhancement of two opposing effects of morphine on seizure threshold. L-NAME (1 mg/kg) reversed the anticonvulsant property of the combination of melatonin (10 mg/kg) plus morphine (0.5 mg/kg). Moreover, L-NAME (5 mg/kg) blocked the enhancing effect of melatonin (10 mg/kg) on proconvulsant activity of morphine (60 mg/kg). Our results indicate that co-administration of melatonin enhances both anti- and proconvulsant effects of morphine via a mechanism that may involve the nitric oxidergic pathway.

Agmatine potentiates morphine-induced conditioned place preference in mice: modulation by alpha2-adrenoceptors.

The effects of agmatine, an endogenous polyamine metabolite formed by decarboxylation of L-arginine, and its combination with morphine on conditioned place preference (CPP) has been investigated in male mice. Our data show that subcutaneous administration of morphine (1-7.5 mg/kg) significantly increases the time spent in the drug-paired compartment in a dose-dependent manner. Intraperitoneal administration of agmatine (1-40 mg/kg) alone does not induce either CPP or conditioned place aversion, while combination of agmatine and subeffective doses of morphine leads to potent rewarding effects. Lower doses of morphine (0.1, 0.05, and 0.01 mg/kg) are able to induce CPP in mice pretreated with agmatine 1, 5, and 10 mg/kg, respectively. Concomitant intraperitoneal administration of UK 14 304 (0.5 mg/kg), a highly selective alpha2-agonist, with per se noneffective dose of morphine (0.5 mg/kg) and also its combination with noneffective doses of agmatine (1 mg/kg) plus morphine (0.05 mg/kg) produces significant CPP. UK 14 304 (0.05, 0.5 mg/kg) alone, or in combination with agmatine (1, 5 mg/kg) have had no effect. We have further investigated the possible involvement of the alpha2-adrenoceptors in the potentiating effect of agmatine on morphine-induced place preference. Selective alpha2-antagonists, yohimbine (0.005 mg/kg) and RX821002 (0.1, 0.5 mg/kg), block the CPP induced by concomitant administration of agmatine (5 mg/kg) and morphine (0.05 mg/kg). Yohimbine (0.001-0.05 mg/kg) or RX821002 (0.05-0.5 mg/kg) alone or in combination with morphine (0.05 mg/kg) or agmatine (5 mg/kg) fail to show any significant place preference or aversion. Our results indicate that pretreatment of animals with agmatine enhances the rewarding properties of morphine via a mechanism which may involve alpha2-adrenergic receptors.

Rewarding properties of sildenafil citrate in mice: role of the nitric oxide-cyclic GMP pathway.

RATIONALE: Sildenafil citrate is widely prescribed for erectile dysfunction and acts by inhibiting phosphodiesterase type-5, resulting in accumulation of cyclic-guanosine monophosphate (cGMP) via activation of nitric oxide synthase (NOS). The nitric oxide (NO) system is relevant to the rewarding effects of various drugs of abuse. Several epidemiologic studies indicate that sildenafil is abused in a recreational fashion. OBJECTIVES: In the present study, the rewarding properties of sildenafil and probable involvement of the NO-cGMP pathway were investigated in adult male NMRI mice. METHODS: The ability of sildenafil citrate (1-40 mg/kg) to produce conditioned place preference (CPP) was studied in an unbiased CPP paradigm. The effects of NO precursor L-arginine, nonselective NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), and the inhibitor of guanylyl cyclase methylene blue (MB) on sildenafil-induced CPP were assessed. RESULTS: Mice that received sildenafil (20 and 40 mg/kg) in one environment during conditioning phase displayed a preference for this environment. Both L-NAME (5 mg/kg) and MB (1 mg/kg) in combination with sildenafil (20 mg/kg) suppressed the acquisition of sildenafil-induced place preference. Lower and per se noneffective dose of sildenafil (10 mg/kg) and L-arginine (60 mg/kg), when coadministered, exerted a significant place conditioning. CONCLUSIONS: Sildenafil shows rewarding properties that may involve the NO-cGMP pathway.

Involvement of nitric oxide system in enhancement of morphine-induced conditioned place preference by agmatine in male mice.

Agmatine recently has been suggested as a neurotransmitter, is able to interact with various effects of morphine like analgesia and dependence. In this study, the effects of agmatine on rewarding properties of morphine, and the possible involvement of nitric oxide (NO) system has been evaluated in an unbiased conditioned place preference (CPP) paradigm. Agmatine (1, 5 and 10mg/kg, i.p.) alone induced neither CPP nor conditioned place aversion (CPA). Morphine (0.01, 0.05, 0.1 and 0.5mg/kg, s.c.), while unable to show CPP or CPA, induced CPP in mice pretreated with agmatine. L-arginine (200mg/kg, i.p.), a NO precursor, significantly enhanced the effect of agmatine (5mg/kg) on morphine (0.5mg/kg)-induced place preference. NG-nitro-L-arginine methyl ester (L-NAME; 2.5mg/kg, i.p.), a non specific nitric oxide synthase (NOS) inhibitor, and aminoguanidine (50 and 100mg/kg, i.p.), a specific inducible NOS inhibitor, significantly reduced the effect of agmatine (5mg/kg) on morphine (0.5mg/kg)-induced place preference. These results suggest the possible involvement of inducible nitric oxide system in potentiating effects of agmatine on morphine-induced place preference.