Ventricular Anatomy Research Articles

Improving Successful Cannulation of External Ventricular Drain: 3D-Printed Surgical Guide for Inexperienced Neurosurgeons

ObjectiveExternal Ventricular Drain (EVD) is a fundamental neurosurgical procedure that is commonly performed by junior neurosurgeons. Expedient, successful cannulation of the ventricles can be lifesaving. Yet, the free-hand technique of EVD insertion is associated with significant mal-positioning rates. This study aims to improve EVD placement by junior neurosurgeons with the aid of a customized 3D printed surgical guide. MethodsA 3D printed surgical guide was developed and customized to our institution’s EVD insertion procedure. First year neurosurgical residents were taught how to perform pre-operative trajectory planning based on coronal brain images and how to use the surgical guide during standard EVD insertion procedure. Number of passes, accuracy of EVD placement, operative complications, need for revision, and surgeon’s experience with the guide were recorded. Results14 patients underwent guide-assisted EVD insertion by first year neurosurgical residents. Significantly, 6 (43%) patients had ventricular anatomy distorted by midline shift. All surgeons achieved successful ventricular cannulation using the EVD guide on first pass (100%). 13 out of 14 (93%) of the guide-assisted EVDs were optimally placed (Karkarla Grade 1). 1 (7%) guide-assisted EVD was suboptimally placed (Karkarla Grade 2). There was no intra or post-operative complication and there was no EVD revision. ConclusionsFor inexperienced surgeons, the 3D printed EVD guide can improve ventricular cannulation even in cases of altered ventricular anatomy. The benefit of 3D printing would also allow the guide to be widely adopted by other institutions worldwide.

Predictors of Hydrocephalus Risk After Stereotactic Radiosurgery for Vestibular Schwannomas: Utility of the Evans Index.

Hydrocephalus after Gamma Knife® stereotactic radiosurgery (SRS) for vestibular schwannomas is a rare but manageable occurrence. Most series report post-SRS communicating hydrocephalus in about 1% of patients, thought to be related to a release of proteinaceous substances into the cerebrospinal fluid. While larger tumor size and older patient age have been associated with post-SRS hydrocephalus, the influence of baseline ventricular anatomy on hydrocephalus risk remains poorly defined. A single-institution retrospective cohort study examining patients who developed symptomatic communicating hydrocephalus after undergoing Gamma Knife® SRS for unilateral vestibular schwannomas from 2011 to 2021 was performed. Patients with prior hydrocephalus and cerebrospinal fluid diversion or prior surgical resection were excluded. Baseline tumor volume, third ventricle width, and Evans Index (EI)-maximum width of the frontal horns of the lateral ventricles/maximum internal diameter of the skull-were measured on axial postcontrast T1-weighted magnetic resonance imaging. A total of 378 patients met the inclusion criteria; 14 patients (3.7%) developed symptomatic communicating hydrocephalus and 10 patients (2.6%) underwent shunt placement and 4 patients (1.1%) were observed with milder symptoms. The median age of patients who developed hydrocephalus was 69 years (IQR, 67-72) and for patients younger than age 65 years, the risk was 1%. For tumor volumes <1 cm3, the risk of requiring shunting was 1.2%. The odds of developing symptomatic hydrocephalus were 5.0 and 7.7 times higher in association with a baseline EI > 0.28 (P = .024) and tumor volume >3 cm3 (P = .007), respectively, in multivariate analysis. Fourth ventricle distortion on pre-SRS imaging was significantly associated with hydrocephalus incidence (P < .001). Patients with vestibular schwannoma with higher baseline EI, larger tumor volumes, and fourth ventricle deformation are at increased odds of developing post-SRS hydrocephalus. These patients should be counseled regarding risk of hydrocephalus and carefully monitored after SRS.

Load Dependency of Ventricular Pump Function: Impact on the Non-Invasive Evaluation of the Severity and the Prognostic Relevance of Myocardial Dysfunction.

Ventricular pump function, which is determined by myocyte contractility, preload and afterload, and, additionally, also significantly influenced by heart rhythm, synchrony of intraventricular contraction and ventricular interdependence, explains the difficulties in establishing the contribution of myocardial contractile dysfunction to the development and progression of heart failure. Estimating myocardial contractility is one of the most difficult challenges because the most commonly used clinical measurements of cardiac performance cannot differentiate contractility changes from alterations in ventricular loading conditions. Under both physiological and pathological conditions, there is also a permanent complex interaction between myocardial contractility, ventricular anatomy and hemodynamic loading conditions. All this explains why no single parameter can alone reveal the real picture of ventricular dysfunction. Over time there has been increasing recognition that a load-independent contractility parameter cannot truly exist, because loading itself changes the myofilament force-generating capacity. Because the use of a single parameter is inadequate, it is necessary to perform multiparametric evaluations and also apply integrative approaches using parameter combinations which include details about ventricular loading conditions. This is particularly important for evaluating the highly afterload-sensitive right ventricular function. In this regard, the existence of certain reluctance particularly to the implementation of non-invasively obtainable parameter combinations in the routine clinical praxis should be reconsidered in the future. Among the non-invasive approaches used to evaluate ventricular function in connection with its current loading conditions, assessment of the relationship between ventricular contraction (e.g., myocardial displacement or deformation) and pressure overload, or the relationship between ejection volume (or ejection velocity) and pressure overload, as well as the relationship between ventricular dilation and pressure overload, were found useful for therapeutic decision-making. In the future, it will be unavoidable to take the load dependency of ventricular function much more into consideration. A solid basis for achieving this goal will be obtainable by intensifying the clinical research necessary to provide more evidence for the practical importance of this largely unsolved problem.

Optimizing indirect targeting of the centromedian nucleus for deep brain stimulation by incorporating third ventricular anatomy.

Deep brain stimulation (DBS) of the centromedian nucleus (CM) is used to treat diverse brain diseases including epilepsy, Tourette syndrome, and disorders of consciousness. However, the CM is challenging to visualize on routine MRI. Many surgeons use an indirect targeting method based on established stereotactic coordinates. The authors aimed to quantify how often a DBS electrode's contacts were positioned within the CM using this approach, and to identify alternative indirect coordinates that are more accurate. Indirect targeting of the CM was performed on 100 MR images obtained in healthy adults, and the resulting coordinates were warped to a common brain template. To estimate positions of DBS contacts along this trajectory, the authors developed a probable electrode location (PEL) mask, modeled on trajectory angles obtained from prior clinical cases. Euclidean and x, y, and z distances between the centroids of the PEL mask and an atlas-based CM mask were measured and defined as error. The percentage of overlaps between the PEL mask and nearby thalamic nuclei was determined. To assess the clinical utility of this methodology, the analysis was validated using 20 MR images obtained in patients with generalized epilepsy, a common clinical indication for CM-DBS. Using standard indirect coordinates, the authors found the average Euclidean error to be 4.40 ± 1.05 mm, and the x, y, and z errors were 4.19 ± 0.97 mm, 0.73 ± 0.65 mm, and 0.66 ± 0.69 mm, respectively. The PEL mask overlap was 52% with the CM and 65% with the ventral posteromedial nucleus. Variation in third ventricular width was the dominant contributor to these errors (r = -0.71). To overcome this variation, the authors developed alternative indirect coordinates: 4.5 mm lateral to the posterolateral corner of the third ventricle at the level of the posterior commissure. With this refinement, the average Euclidean error was reduced to 1.24 ± 0.5 mm, with 84% of the PEL mask within the CM. The unavailability of advanced MRI for direct targeting limits access to CM-DBS in resource-constrained neurosurgical programs. Standard indirect coordinates do not provide optimal targeting of the CM, with most contacts laterally placed in the sensory thalamus. The proposed indirect approach may therefore increase the accuracy and availability of CM-DBS, while reducing side effects.

Revisiting the anatomy of the left ventricle in the light of knowledge of its development.

Despite centuries of investigation, certain aspects of left ventricular anatomy remain either controversial or uncertain. We make no claims to have resolved these issues, but our review, based on our current knowledge of development, hopefully identifies the issues requiring further investigation. When first formed, the left ventricle had only inlet and apical components. With the expansion of the atrioventricular canal, the developing ventricle cedes part of its inlet to the right ventricle whilst retaining the larger parts of the cushions dividing the atrioventricular canal. Further remodelling of the interventricular communication provides the ventricle with its outlet, with the aortic root being transferred to the left ventricle along with the newly formed myocardium supporting its leaflets. The definitive ventricle possesses inlet, apical and outlet parts. The inlet component is guarded by the mitral valve, with its leaflets, in the normal heart, supported by papillary muscles located infero-septally and supero-laterally. There is but a solitary zone of apposition between the leaflets, which we suggest are best described as being aortic and mural. The trabeculated component extends beyond the inlet to the apex and is confluent with the outlet part, which supports the aortic root. The leaflets of the aortic valve are supported in semilunar fashion within the root, with the ventricular cavity extending to the sinutubular junction. The myocardial-arterial junction, however, stops well short of the sinutubular junction, with myocardium found only at the bases of the sinuses, giving rise to the coronary arteries. We argue that the relationships between the various components should now be described using attitudinally appropriate terms rather than describing them as if the heart is removed from the body and positioned on its apex.

4-Dimensional Right Ventricular Outflow Tract Segmentation to Evaluate Candidacy for Transcatheter Pulmonary Valve Replacement.

Candidacy for transcatheter pulmonary valve replacement utilizing newer valve platforms is aided by industry-driven fit analyses. We report augmentation of this decision-making process by visualization of 4-dimensional cine imaging of patient-specific right ventricular outflow tract anatomy and a virtual valve model within a virtual reality platform.

Left Ventricular Outflow Tract Anatomy as a Predictor of Conduction Disturbances after Transcatheter Aortic Valve Implantation

Left Ventricular Outflow Tract Anatomy as a Predictor of Conduction Disturbances after Transcatheter Aortic Valve Implantation

Third Ventricle Diameter Is Inversely Related to Thalamic Massa Intermedia Thickness in Hydrocephalus Caused by Congenital Aqueductal Stenosis.

In fetuses with lateral ventriculomegaly and normal posterior fossa cerebrospinal spaces, third ventricle distention is a compelling clue that supports a diagnosis of aqueductal stenosis. However, this association assumes normal ventricular anatomy. Structural constraints can impair pressure-induced compliance. We aimed to determine how thalamic massa intermedia size alterations may impact the size of the third ventricle in the setting of congenital aqueductal stenosis. This retrospective study was performed at a single academic pediatric hospital after institutional review board approval. We searched our brain MRI reports for all examinations describing aqueductal stenosis and included all the patients who had both fetal and postnatal examinations. Patients with interhypothalamic adhesions and hydrocephalus unrelated to congenital aqueductal stenosis were excluded from this study. We evaluated all the MRIs for the presence of thalamic massa intermedia and documented third ventricle diameters (supraoptic recess, central and suprapineal recesses) and the thalamic massa intermedia circumference. The Spearman correlation was used to identify the potential relationship between the thalamic massa intermedia circumference and third ventricle size in fetal and postnatal MRIs. Patients were also stratified into 2 groups based on the presence or absence of thalamic massa intermedia. Mann-Whitney U tests were used to compare third ventricle diameters between these groups. The study included both fetal and postnatal studies from 59 patients. The overall third ventricle diameter was inversely proportional to the circumference of the thalamic massa intermedia in both groups (fetal: P = .001, ρ = -0.422; [95% CI, -0.628 to -0.181]; postnatal: P < .001, ρ = -0.653; [95% CI, -0.782 to -0.479]). Nonetheless, dilation of anterior and posterior recesses still occurred when the mid third ventricle was nondilated or less severely dilated in patients with an enlarged thalamic massa intermedia. Third ventricle dilation was most severe in patients lacking a thalamic massa intermedia compared with patients with a thalamic massa intermedia (P < .001). In patients with suspected congenital aqueductal stenosis, lack of marked third ventriculomegaly as conventionally measured can sometimes be explained by thickening of the thalamic massa intermedia. In this circumstance, it is important to evaluate the extreme recesses of the third ventricle for evidence of dilation on fetal MRI.

Development of an adjustable patient-specific rigid guide to improve the accuracy of external ventricular catheter placement.

The most common method for external ventricular drain (EVD) placement is the freehand approach, which has reported inaccuracy rates of 12.3%-44.9%, especially in the case of altered ventricular anatomy. Current assistive devices require added time or equipment or do not account for shifted ventricles. To improve the accuracy of emergent EVD placement in the setting of altered ventricular anatomy, the authors designed a patient-specific EVD (PS-EVD) guide. The PS-EVD guide has a tripod base and a series of differently angled inserts that lock in place at multiple rotational positions, allowing for numerous insertion angles. For testing, the authors designed a 3D-printed phantom skull with a gelatin brain analog containing ventricles simulating normal and altered ventricular anatomy. Low-resolution CT scans of the phantom were used to calculate the insertion angle in relation to the standard perpendicular entry. The corresponding insert at the correct rotational position within the base unit was positioned over the entry point on the phantom, and the catheter was inserted. Accuracy was evaluated with repeat CT scans. With normal ventricular anatomy, as well as abnormally shifted ventricles, proper use of the PS-EVD guide led to accurate catheter insertion into the ventricle in trials, as confirmed on coronal and sagittal CT images, including cases in which a perpendicular trajectory, such as with the Ghajar guide, was insufficient. The PS-EVD guide allows consistent and accurate EVD placement in phantom skulls with both normal and altered ventricular anatomy. Further trials comparing this device to the freehand approach are required.

Imaging Features of Arrhythmogenic Cardiomyopathies.

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by replacement of ventricular myocardium with fibrofatty tissue, predisposing the patient to ventricular arrhythmias and/or sudden cardiac death. Most cases of ACM are associated with pathogenic variants in genes that encode desmosomal proteins, an important cell-to-cell adhesion complex present in both the heart and skin tissue. Although ACM was first described as a disease predominantly of the right ventricle, it is now acknowledged that it can also primarily involve the left ventricle or both ventricles. The original right-dominant phenotype is traditionally diagnosed using the 2010 task force criteria, a multifactorial algorithm divided into major and minor criteria consisting of structural criteria based on two-dimensional echocardiographic, cardiac MRI, or right ventricular angiographic findings; tissue characterization based on endomyocardial biopsy results; repolarization and depolarization abnormalities based on electrocardiographic findings; arrhythmic features; and family history. Shortfalls in the task force criteria due to the modern understanding of the disease have led to development of the Padua criteria, which include updated criteria for diagnosis of the right-dominant phenotype and new criteria for diagnosis of the left-predominant and biventricular phenotypes. In addition to incorporating cardiac MRI findings of ventricular dilatation, systolic dysfunction, and regional wall motion abnormalities, the new Padua criteria emphasize late gadolinium enhancement at cardiac MRI as a key feature in diagnosis and imaging-based tissue characterization. Conditions to consider in the differential diagnosis of the right-dominant phenotype include various other causes of right ventricular dilatation such as left-to-right shunts and variants of normal right ventricular anatomy that can be misinterpreted as abnormalities. The left-dominant phenotype can mimic myocarditis at imaging and clinical examination. Additional considerations for the differential diagnosis of ACM, particularly for the left-dominant phenotype, include sarcoidosis and dilated cardiomyopathy. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Mechanical Circulatory Support for High-Risk Percutaneous Coronary Intervention.

This review will focus on the indications of mechanical circulatory support (MCS) for high-risk percutaneous coronary intervention (PCI) and then analyze in detail all MCS devices available to the operator, evaluating their mechanisms of action, pros and cons, contraindications, and clinical data supporting their use. Over the last decade, the interventional cardiology arena has witnessed an increase in the complexity profile of the patients and lesions treated in the catheterization laboratory. Patients with significant comorbidity burden, left ventricular dysfunction, impaired hemodynamics, and/or complex coronary anatomy often cannot tolerate extensive percutaneous revascularization. Therefore, a variety of MCS devices have been developed and adopted for high-risk PCI. Despite the variety of MCS available to date, a detailed characterization of the patient requiring MCS is still lacking. A precise selection of patients who can benefit from MCS support during high-risk PCI and the choice of the most appropriate MCS device in each case are imperative to provide extensive revascularization and improve patient outcomes. Several new devices are being tested in early feasibility studies and randomized clinical trials and the experience gained in this context will allow us to provide precise answers to these questions in the coming years.

Spontaneous delayed CSF rhinorrhea associated with encephalocele following surgical resection of a giant frontoparietal meningioma, an extremely rare entity and overlook of English literature

Introduction and importance: Spontaneous cerebrospinal fluid (CSF) rhinorrhea without a history of head trauma is rare. The authors describe a scarce case of spontaneous, nontraumatic, delayed CSF rhinorrhea due to ethmoidal encephalocele associated with frontoparietal giant meningioma. Case presentation: A 49-year-old male complained of a slowly growing skull mass lasting 10 years since a blunt head trauma and progressive hemiparesis 3 months ago and was referred to our center. There was a heterogeneous extra-axial mass (77×77×70 mm) with calcified components at his right frontal lobe, demonstrating notable adjacent parenchymal edema and a midline shift to the left. There was a sizeable extra-axial mass (113×95×80 mm) in his right front-temporoparietal lobe associated with adjacent invasion to calvarium leading to the lytic and sclerotic appearance of the calvarial bone showing intense heterogeneous contrast enhancement and an adjacent enhancing dural tail. A considerable mass effect on the adjacent frontotemporal cortex is evident, with mild parenchymal edema leading to a notable midline shift to the left, right uncal herniation, and left ventriculomegaly. On postoperation day 5, the patient developed a recurrent CSF leak exacerbated by hydrocephalus. He was rescheduled to undergo endoscopic endonasal surgery and dural repair on postoperative day 7. The postoperative course was uneventful. Clinical discussion: Frontoparietal lobe encephaloceles represent the least common cause of spontaneous CSF rhinorrhea. Early diagnosis and surgical management remain crucial to minimize the subsequent complications. Conclusion: The ventricular anatomy and CSF fluid dynamics alteration following tumor surgical resection seem to contribute to an environment by which a herniated ethmoidal encephalocele developed a delayed nontraumatic CSF leak.

Magnetic resonance imaging with upconversion nanoprobes capable of crossing the blood-cerebrospinal fluid barrier

The central nervous system (CNS) maintains homeostasis with its surrounding environment by restricting the ingress of large hydrophilic molecules, immune cells, pathogens, and other external harmful substances to the brain. This function relies heavily on the blood-cerebrospinal fluid (B-CSF) and blood-brain barrier (BBB). Although considerable research has examined the structure and function of the BBB, the B-CSF barrier has received little attention. Therapies for disorders associated with the central nervous system have the potential to benefit from targeting the B-CSF barrier to enhance medication penetration into the brain. In this study, we synthesized a nanoprobe ANG-PEG-UCNP capable of crossing the B-CSF barrier with high targeting specificity using a hydrocephalus model for noninvasive magnetic resonance ventriculography to understand the mechanism by which the CSF barrier may be crossed and identify therapeutic targets of CNS diseases. This magnetic resonance nanoprobe ANG-PEG-UCNP holds promising potential as a safe and effective means for accurately defining the ventricular anatomy and correctly locating sites of CSF obstruction.

Prognostic value of left ventricular structure and strain in chronic kidney disease patients by cardiovascular magnetic resonance imaging: a retrospective study.

Individuals suffering from chronic kidney disease (CKD) frequently face a heightened likelihood of experiencing cardiovascular complications, including heart failure and cardiac mortality. Cardiovascular magnetic resonance feature tracking (CMR-FT) is utilized to assess the micro-contraction function of the myocardium. The objective of this research is to explore the relationship between the left ventricular anatomy, myocardial strain, and the clinical outcomes in patients with CKD. A total of 77 patients with late-stage CKD were enrolled in this retrospective study. They underwent cardiac magnetic resonance imaging and were followed up, with no history of significant cardiac diseases. The patients were divided into two groups: those with a left ventricular global longitudinal strain (LVGLS) ≥ -15.2% (n=49) and those with LVGLS < -15.2% (n=28). The clinical endpoints were defined as hospitalization for heart failure or all-cause mortality. Over an average observation period of 22 ±9 months, 11 (14%) patients passed away and 30 (39%) were admitted to the hospital for heart failure, with eight encountering both incidents. Those with LVGLS ≥ -15.2% had markedly lower rates of event-free survival concerning heart failure admissions and overall mortality than their counterparts (log-rank P=0.014). Cox multivariable analysis indicated that reduced LVGLS consistently predicted a higher likelihood of combined outcomes of heart failure admissions and total mortality (HR: 3.40, 95% CI [1.35-8.56], P=0.009), even when factoring in age, diabetes, left atrial diameter, and left ventricular mass index (LVMI). However, the LVMI showed no significant correlation with the risk of heart failure admissions or overall mortality. Compared to patients with LVGLS < -15.2%, CKD patients with LVGLS ≥ -15.2% have an increased risk of heart failure hospitalization and all-cause mortality. The prognostic role of LVMI in assessing CKD patients among the Asian population requires further investigation.

Endoscopic Third Ventriculostomy: long term results

Objective: Hydrocephalus is a major cause of morbidity in the pediatric population, with potentially severe consequences if left untreated hydrocephalus.&#x0D; Endoscopic third ventriculostomy (ETV) has become the method of choice in the treatment of obstructive hydrocephalus. However, age, ventricular anatomy, and etiology could determine success rates (SR) of ETV. The aim of this study was to identify putative factors that could influence the outcome of ETV in children.&#x0D; Methods: Clinical data of 148 consecutive patients under 18 years of age who underwent 150 consecutive ETVs from January 2000 to January 2019 were reviewed. Data were analyzed with regards to clinical and radiological SR. The actual long-term SR was compared to that predicted by the ETV Success Score (ETVSS) model.&#x0D; Results/Discussion: The study group included 63 males (43%) and 85 females (57%) ranging in age from 11 days to 18 years (mean age of, 6.17 ± 1.02 years; median age 4.5 years) at surgery. Concerning the etiology of hydrocephalus, tumors and aqueductal stenosis (AS) were the most frequently observed, with each occurring in 43 cases (29%), followed by malformations in 31 (21%), cystic lesions in 7 (5%) and other etiologies in 67 patients (16%). The overall SR at the first ETV attempt was 80% (118/148), compared to 74.8% (variance 14.35, 95% CI 69.37–78.22) predicted by the ETVSS. Regarding age, SR was 58% in patients under 6 months of age, 65% in children between 6 months and 1 year, and 86% in children older than 1 year. SR for AS and hydrocephalus associated with posterior fossa tumors were 88 and 90%, respectively. Unsatisfactory results were related to previous intraventricular hemorrhage and infection. The overall complication rate in this series was 13%.&#x0D; The lower SR after ETV in young children may be explained by the poor CSF reabsorption capacity of newborn infants due to immaturity of the arachnoid granulations;&#x0D; Univariate and multivariate analysis showed in our series that both the etiology of hydrocephalus and patient´s age group were relevant factors predicting success.&#x0D; A literature review showed that SR in children under 6 months of age ranged from 32% to 45%, and in children older than one year it ranged from 56% to 71%. A few studies have analyzed the postoperative course and SR after a period of 3 years.&#x0D; Conclusion: ETV is safe and effective in children. In this series, the age of the patient and etiology of hydrocephalus were related to SR. Also, the ETVSS was accurate to predict outcome. Intraventricular hemorrhage, previous CNS infection, myelomeningocele, prematurity and recurrent shunt revisions have been associated with high failure rates of ETV in all age groups, particularly in infants under 6 months of age. In a long-term follow-up, surgical experience was statistically significant in reducing complications.

Fast cardiac magnetic resonance protocol. Feasibility of accelerated compressed sensing cine sequences in clinical practice

ObjectiveTo demonstrate the feasibility of cardiac magnetic resonance (CMR) cine sequences with compressed-sensing (CS) acceleration in the assessment of ventricular anatomy, volume, and function; and to present a fast CRM protocol that improves scan efficiency. MethodsProspective study of consecutive patients with indication for CMR who underwent CS short-axis (SA) cine imaging compared with conventional SA cine imaging. We analysed ejection fraction (EF), end-diastolic volume (EDV), stroke volume (SV), and myocardial thickness. Two blinded independent observers performed the reading. Inter- and intraobserver agreement was calculated for all the measurements. Image quality of conventional and CS cine sequences was also assessed. ResultsA total of 50 patients were included, 22 women (44%) with a mean age of 57.3 ± 13.2 years. Mean left ventricular EF was 59.1% ± 10.4% with the reference steady-state free precession sequences, versus 58.7% ± 10.6% with CS; and right ventricular EF with conventional imaging was 59.3% ± 5.7%, versus 59.5% ± 6.1% with CS. Mean left ventricular EDV for conventional sequences and CS were 166.8 and 165.1 ml respectively; left ventricular SV was 94.5 versus 92.6 ml; right ventricular EDV was 159.3 versus 156.4 ml; and right ventricular SV was 93.6 versus 91.2 ml, respectively. Excellent intra and interobserver correlations were obtained for all parameters (Intraclass correlation coefficient between 0.932 and 0.99; CI: 95%). There were also no significant differences in ventricular thickness (12.9 ± 2.9 mm vs 12.7 ± 3.1 mm) (p < .001). The mean time of CS SA was <40 sec versus 6–8 min for the conventional SA. The mean duration of the complete study was 15 ± 3 min. ConclusionsCine CS sequences are feasible for assessing biventricular function, volume, and anatomy, enabling fast CMR protocols.

Protocolo rápido de resonancia magnética cardiaca. Viabilidad de las secuencias cine aceleradas con compressed sensing en la práctica clínica

ObjectiveTo demonstrate the feasibility of cardiac magnetic resonance (CMR) cine sequences with compressed-sensing (CS) acceleration in the assessment of ventricular anatomy, volume, and function; and to present a fast CRM protocol that improves scan efficiency. MethodsProspective study of consecutive patients with indication for CMR who underwent CS short-axis (SA) cine imaging compared with conventional SA cine imaging. We analysed ejection fraction (EF), end-diastolic volume (EDV), stroke volume (SV), and myocardial thickness. Two blinded independent observers performed the reading. Inter- and intraobserver agreement was calculated for all the measurements. Image quality of conventional and CS cine sequences was also assessed. ResultsA total of 50 patients were included, 22 women (44%) with a mean age of 57.3±13.2 years. Mean left ventricular EF was 59.1%±10.4% with the reference steady-state free precession sequences, versus 58.7%±10.6% with CS; and right ventricular EF with conventional imaging was 59.3%±5.7%, versus 59.5%±6.1% with CS. Mean left ventricular EDV for conventional sequences and CS were 166.8 and 165.1ml respectively; left ventricular SV was 94.5 versus 92.6ml; right ventricular EDV was 159.3 versus 156.4 ml; and right ventricular SV was 93.6 versus 91.2ml, respectively. Excellent intra and interobserver correlations were obtained for all parameters (Intraclass correlation coefficient between 0.932 and 0.99; CI: 95%). There were also no significant differences in ventricular thickness (12.9±2.9mm vs. 12.7±3.1mm) (p<.001). The mean time of CS SA was <40 sec versus 6-8 min for the conventional SA. The mean duration of the complete study was 15±3 min. ConclusionsCine CS sequences are feasible for assessing biventricular function, volume, and anatomy, enabling fast CMR protocols.

143 Elucidating the Function of the Wnt Signaling Pathway in Hydrocephalus

INTRODUCTION: Although acquired hydrocephalus is commonly encountered by neurosurgeons, our understanding of the mechanisms underlying its pathogenesis remain poor. Furthermore, normal CSF physiology is dependent on the proper function of ventricular ependymal cells and choroid plexus epithelium (CPE), although few neurosurgical studies have addressed the functions of these cells. METHODS: Alteration of the Wnt pathway is achieved by generating FoxJ1-Cre;Apclox/lox and FoxJ1-Cre;Ctnnb1lox/lox mice, which express Cre upon induction with tamoxifen, as well as via intraventricular delivery of an AAV1-eGFP-Cre in Apclox/lox and Ctnnb1lox/lox mice. T2 weighted MRI with 3D volumetrics is applied to assess ventricular anatomy, in addition to standard molecular biology techniques to examine downstream signaling mechanisms. Kaolin and whole blood injection are used as models of obstructive and communicating hydrocephalus, respectively. RESULTS: B-catenin is strongly expressed in adult mouse ependyma and CPE, suggesting that the canonical Wnt pathway continues to be active after these cells have developed. Moreover, up-regulation of this pathway in adult FoxJ1-Cre;Apclox/lox mice results in significant ventricular enlargement (n = 3; p = 0.03). Both FoxJ1-Cre transgenic mice and intraventricular AAV1-eGFP-Cre drive selective expression within ependyma and CPE, suggesting that these may be useful models for investigating important molecular pathways within these cells. CONCLUSIONS: Our data suggests that the canonical Wnt signaling pathway plays a role in the maintenance of normal adult CSF dynamics. Moreover, we show selective targeting of ependyma and CPE using an adeno-associated virus, which may represent a novel strategy for modifying genes and/or proteins involved in CSF regulation.

Factors associated with the need for inotropic support following pulmonary artery banding surgery for CHD.

We aimed to identify factors independently associated with the need for inotropic support for low cardiac output or haemodynamic instability after pulmonary artery banding surgery for CHD. We performed a retrospective chart review of all neonates and infants who underwent pulmonary banding between January 2016 and June 2019 at our institution. Bivariate and multivariable analyses were performed to identify factors independently associated with the use of post-operative inotropic support, defined as the initiation of inotropic infusion(s) for depressed myocardial function, hypotension, or compromised perfusion within 24 hours of pulmonary artery banding. We reviewed 61 patients. Median age at surgery was 10 days (25%,75%:7,30). Cardiac anatomy was biventricular in 38 patients (62%), hypoplastic right ventricle in 14 patients (23%), and hypoplastic left ventricle in 9 patients (15%). Inotropic support was implemented in 30 patients (49%). Baseline characteristics of patients who received inotropic support, including ventricular anatomy and pre-operative ventricular function, were not statistically different from the rest of the cohort. Patients who received inotropic support, however, were exposed to larger cumulative doses of ketamine intraoperatively - median 4.0 mg/kg (25%,75%:2.8,5.9) versus 1.8 mg/kg (25%,75%:0.9,4.5), p < 0.001. In a multivariable model, cumulative ketamine dose greater than 2.5mg/kg was associated with post-operative inotropic support(odds ratio 5.5; 95% confidence interval: 1.7,17.8), independent of total surgery time. Inotropic support was administered in approximately half of patients who underwent pulmonary artery banding and more commonly occurred in patients who received higher cumulative doses of ketamine intraoperatively, independent of the duration of surgery.

Impact of Ventricular Geometric Characteristics on Myocardial Stiffness Assessment Using Shear-Wave Velocity in Healthy Children and Young Adults

Diastolic myocardial stiffness (MS) can serve as a key diagnostic parameter for congenital or acquired heart diseases. Using shear modulus and shear-wave velocity (SWV), shear-wave elastography (SWE) is an emerging ultrasound-based technique that can allow noninvasive assessment of MS. However, MS extrinsic parameters such as left ventricular geometric characteristics could affect shear-wave propagation. The aims of this study were to determine a range of normal values of MS using SWE in age groups of healthy children and young adults and to explore the impact of left ventricular geometric characteristics on SWE. Sixty healthy volunteers were recruited in the study and divided into 2 groups: neonates (0-1 months old, n=15) and >1month old (1month to 45years of age, n=45). SWE was performed using the Verasonics Vantage systems with a phased-array ultrasound probe. The anteroseptal basal segment was assessed in two views. SWE was electrocardiographically triggered during the end-diastolic phase. Conventional echocardiography was performed to assess ventricular function and anatomy. Results are presented as stiffness values along with mean velocity measurements and SDs. Simple and multivariate linear regression analyses were performed. For neonates, mean MS was 1.87±0.79kPa (range, 0.59-2.91kPa; mean SWV, 1.37±0.57m/sec), with high variability and no correlation with age (P=.239). For this age group, no statistically significant correlation was found between MS and any demographic or echocardiographic parameters (P>.05). For the >1month old group, a mean MS value of 1.67±0.53kPa was observed (range, 0.6-3kPa; mean SWV, 1.29±0.49m/sec) for healthy volunteers. When paired for age, no sex-related difference was observed (P=.55). In univariate linear regression analysis, age (r=0.83, P<.01), diastolic interventricular septal thickness (r=0.72, P<.01), and left ventricular end-diastolic diameter (r=0.67, P<.01) were the parameters with the highest correlation coefficients with MS. In a multiple linear regression analysis incorporating these three parameters as cofounding factors, age was the only statistically significant parameters (r=0.81, P=.02). Diastolic MS increases linearly in children and young adults. Diastolic MS correlates more robustly with age than with myocardial and left ventricular geometric characteristics. However, the geometry affects SWV, implying the need to determine well-established boundaries in future studies for the clinical application of SWE.