Clustering of match running and performance indicators to assess between- and within-playing position similarity in professional rugby league.

This study aimed to determine the similarity between and within positions in professional rugby league in terms of technical performance and match displacement. Here, the analyses were repeated on 3 different datasets which consisted of technical features only, displacement features only, and a combined dataset including both. Each dataset contained 7617 observations from the 2018 and 2019 Super League seasons, including 366 players from 11 teams. For each dataset, feature selection was initially used to rank features regarding their importance for predicting a player's position for each match. Subsets of 12, 11, and 27 features were retained for technical, displacement, and combined datasets for subsequent analyses. Hierarchical cluster analyses were then carried out on the positional means to find logical groupings. For the technical dataset, 3 clusters were found: (1) props, loose forwards, second-row, hooker; (2) halves; (3) wings, centres, fullback. For displacement, 4 clusters were found: (1) second-rows, halves; (2) wings, centres; (3) fullback; (4) props, loose forward, hooker. For the combined dataset, 3 clusters were found: (1) halves, fullback; (2) wings and centres; (3) props, loose forward, hooker, second-rows. These positional clusters can be used to standardise positional groups in research investigating either technical, displacement, or both constructs within rugby league.

Latent variable dose-response modelling of external training load measures and musculoskeletal responses in elite rugby league players.

Establishing dose-response relationships between training load and fatigue can help the planning of training. The aim was to establish the relative importance of external training load measurements to relate to the musculoskeletal response on a group and individual player level. Sixteen elite male rugby league players were monitored across three seasons. Two- to seven-day exponential weighted averages (EWMA) were calculated for total distance, and individualised speed thresholds (via 30-15 Intermittent Fitness Test) derived from global positioning systems. The sit and reach, dorsiflexion lunge, and adductor squeeze tests represented the musculoskeletal response. Partial least squares and repeated measures correlation analyses established the relative importance of training load measures and then investigated their relationship to the collective musculoskeletal response for individual players through the construction of latent variables. On a group level, 2- and 3-day EWMA total distance had the highest relative importance to the collective musculoskeletal response (p < 0.0001). However, the magnitude of relationships on a group (r value = 0.20) and individual (r value = 0.06) level were trivial to small. The lack of variability in the musculoskeletal response over time suggest practitioners adopting such measures to understand acute musculoskeletal fatigue responses should do so with caution.

Achieving a desired training intensity through the prescription of external training load variables in youth sport: More pieces to the puzzle required.

Identifying the external training load variables which influence subjective internal response will help reduce the mismatch between coach-intended and athlete-perceived training intensity. Therefore, this study aimed to reduce external training load measures into distinct principal components (PCs), plot internal training response (quantified via session Rating of Perceived Exertion [sRPE]) against the identified PCs and investigate how the prescription of PCs influences subjective internal training response. Twenty-nine school to international level youth athletes wore microtechnology units for field-based training sessions. SRPE was collected post-session and assigned to the microtechnology unit data for the corresponding training session. 198 rugby union, 145 field hockey and 142 soccer observations were analysed. The external training variables were reduced to two PCs for each sport cumulatively explaining 91%, 96% and 91% of sRPE variance in rugby union, field hockey and soccer, respectively. However, when internal response was plotted against the PCs, the lack of separation between low-, moderate- and high-intensity training sessions precluded further analysis as the prescription of the PCs do not appear to distinguish subjective session intensity. A coach may therefore wish to consider the multitude of physiological, psychological and environmental factors which influence sRPE alongside external training load prescription.

Time to embrace the complexity when analysing GPS data? A systematic review of contextual factors on match running in rugby league.

This systematic review aimed to identify and summarise associations between currently identified contextual factors and match running in senior male professional rugby league. Eligible articles included at least one contextual factor and used GPS to measure at least one displacement variable within competitive senior, male, professional rugby league matches. Of the 15 included studies, the identified contextual factors were grouped into factors related to individual characteristics (n = 3), match result (n = 4), team strength (n = 2), opposition strength (n = 3), match conditions (n = 6), technical and tactical demands (n = 6), spatial and temporal characteristics (n = 7), and nutrition (n = 1). Speed was the most commonly reported measure of match running (100%), followed by distance (47%), and acceleration (20%). Inconsistencies were found between studies for most contextual factors on match running. Higher speeds were generally associated with higher fitness, encountered earlier in the match and whilst defending. All 15 studies utilised a univariate approach to quantify associations of a contextual factor. The inconsistencies found in the associations of given contextual factors highlight the complex and multi-faceted nature of match running. Therefore, practitioners should consider contextual factors when analysing and interpreting GPS data.

The relative contribution of training intensity and duration to daily measures of training load in professional rugby league and union.

This study examined the relative contribution of exercise duration and intensity to team-sport athlete's training load. Male, professional rugby league (n = 10) and union (n = 22) players were monitored over 6- and 52-week training periods, respectively. Whole-session (load) and per-minute (intensity) metrics were monitored (league: session rating of perceived exertion training load [sRPE-TL], individualised training impulse, total distance, BodyLoad™; union: sRPE-TL, total distance, high-speed running distance, PlayerLoad™). Separate principal component analyses were conducted on the load and intensity measures to consolidate raw data into principal components (PC, k = 4). The first load PC captured 70% and 74% of the total variance in the rugby league and rugby union datasets, respectively. Multiple linear regression subsequently revealed that session duration explained 73% and 57% of the variance in first load PC, respectively, while the four intensity PCs explained an additional 24% and 34%, respectively. Across two professional rugby training programmes, the majority of the variability in training load measures was explained by session duration (~60-70%), while a smaller proportion was explained by session intensity (~30%). When modelling the training load, training intensity and duration should be disaggregated to better account for their between-session variability.

The peak duration-specific locomotor demands and concurrent collision frequencies of European Super League rugby.

Understanding the most demanding passages of European Super League competition can optimise training prescription. We established positional and match half differences in peak relative distances (m·min-1) across durations, and the number of collisions, high-speed- and very-high-speed-distance completed in the peak 10 min period. Moving-averages (10 s, 30 s, 1 min, 5 min, 10 min) of instantaneous speed (m·s-1) were calculated from 25 professional rugby league players during 25 matches via microtechnology. Maximal m·min-1 was taken for each duration for each half. Concurrently, collisions (n), high-speed- (5 to 7 m·s-1; m) and very-high-speed-distance (> 7 m·s-1; m) were coded during each peak 10 min. Mixed-effects models determined differences between positions and halves. Aside from peak 10 s, trivial differences were observed in peak m·min-1 between positions or halves across durations. During peak 10 min periods, adjustables, full- and outside-backs ran more at high-speed and very-high-speed whilst middle- and edge-forwards completed more collisions. Peak m·min-1 is similar between positional groups across a range of durations and are maintained between halves of the match. Practitioners should consider that whilst the overall peak locomotor "intensity" is similar, how they achieve this differs between positions with forwards also exposed to additional collision bouts.

Isolated Common Iliac Artery Aneurysms Treated Solely With Iliac Branch Stent-Grafts: Midterm Results of a Multicenter Registry.

PURPOSE: To assess early and midterm outcomes of iliac branch device (IBD) implantation without an aortic stent-graft for the treatment of isolated common iliac artery aneurysm (CIAA). METHODS: From December 2006 to June 2016, 49 isolated CIAAs in 46 patients were treated solely with an IBD at 7 vascular centers. Five patients were lost to follow-up, leaving 41 male patients (mean age 72.5±7.8 years) for analysis. Mean CIAA diameter was 39.1±10.5 mm (range 25-65). Thirty-two patients (2 with bilateral CIAAs) were treated with a Cook Zenith iliac branch device; 9 patients (1 bilateral) received a Gore Excluder iliac branch endoprosthesis. Primary endpoints were technical success, survival, aneurysm exclusion, device patency, and freedom from reintervention at 1 and 5 years. Freedom from major adverse events and aneurysm shrinkage at 1 year were also assessed. RESULTS: Thirty-day mortality and the IBD occlusion rate were 2.4% and 2.3%, respectively. At a mean follow-up of 40.2±33.9 months, no patient presented buttock claudication, erectile dysfunction, or bowel or spinal cord ischemia. Three patients died within 6 months after the procedure. Estimates of cumulative survival, device patency, and freedom from reintervention were 90.2%, 95.2%, and 95.7%, respectively, at 1 and 5 years. At 1 year, CIAA shrinkage ≥5 mm was recorded in 21 of 38 survivors. No evidence of endoleak, device migration, or disconnection was found on imaging follow-up. CONCLUSION: The use of IBDs without an aortic stent-graft for isolated CIAAs resulted in excellent patency, with low morbidity and mortality. This, in conjunction with no endoleak or migration and a low reintervention rate, supports the use of isolated IBDs as a stable and durable means of endovascular reconstruction in cases with suitable anatomy. Longer follow-up and a larger cohort are needed to validate these results.

Bone Density and Cross-sectional Geometry of the Proximal Femur Are Bilaterally Elevated in Elite Cricket Fast Bowlers.

The skeleton of a cricket fast bowler is exposed to a unique combination of gravitational and torsional loading in the form of substantial ground reaction forces delivered through the front landing foot, and anterior-posterior shear forces mediated by regional muscle contractions across the lumbo-pelvic region. The objectives of this study were to compare the hip structural characteristics of elite fast bowlers with recreationally active age-matched controls, and to examine unilateral bone properties in fast bowlers. Dual-energy X-ray absorptiometry of the proximal femur was performed in 26 elite male fast bowlers and 26 normally active controls. Hip structural analysis (GE Lunar; enCORE version 15.0) determined areal bone mineral density (BMD) of the proximal femur, and cross-sectional area, section modulus (Z), cross-sectional moment of inertia, and femoral strength index at the narrow region of the femoral neck. Mean femoral neck and trochanter BMD were greater in fast bowlers than in controls (p <0.001). All bone geometry properties, except for cross-sectional moment of inertia, were superior in fast bowlers (p <0.05) following adjustment for height and lean mass. There were no asymmetries in BMD or bone geometry when considering leg dominance of the fast bowlers (p > 0.05). Elite fast bowlers have superior bone characteristics of the proximal femur, with results inferring enhanced resistance to axial compression (cross-sectional area), and bending (Z) forces, and enhanced strength to withstand a fall impact as indicated by their higher femoral strength index. No asymmetries in hip bone properties were identified, suggesting that both torsional and gravitational loading offer significant osteogenic potential.

The pyramidalis-anterior pubic ligament-adductor longus complex (PLAC) and its role with adductor injuries: a new anatomical concept.

PURPOSE: Adductor longus injuries are complex. The conflict between views in the recent literature and various nineteenth-century anatomy books regarding symphyseal and perisymphyseal anatomy can lead to difficulties in MRI interpretation and treatment decisions. The aim of the study is to systematically investigate the pyramidalis muscle and its anatomical connections with adductor longus and rectus abdominis, to elucidate injury patterns occurring with adductor avulsions. METHODS: A layered dissection of the soft tissues of the anterior symphyseal area was performed on seven fresh-frozen male cadavers. The dimensions of the pyramidalis muscle were measured and anatomical connections with adductor longus, rectus abdominis and aponeuroses examined. RESULTS: The pyramidalis is the only abdominal muscle anterior to the pubic bone and was found bilaterally in all specimens. It arises from the pubic crest and anterior pubic ligament and attaches to the linea alba on the medial border. The proximal adductor longus attaches to the pubic crest and anterior pubic ligament. The anterior pubic ligament is also a fascial anchor point connecting the lower anterior abdominal aponeurosis and fascia lata. The rectus abdominis, however, is not attached to the adductor longus; its lateral tendon attaches to the cranial border of the pubis; and its slender internal tendon attaches inferiorly to the symphysis with fascia lata and gracilis. CONCLUSION: The study demonstrates a strong direct connection between the pyramidalis muscle and adductor longus tendon via the anterior pubic ligament, and it introduces the new anatomical concept of the pyramidalis-anterior pubic ligament-adductor longus complex (PLAC). Knowledge of these anatomical relationships should be employed to aid in image interpretation and treatment planning with proximal adductor avulsions. In particular, MRI imaging should be employed for all proximal adductor longus avulsions to assess the integrity of the PLAC.

Aqueductal cerebrospinal fluid pulsatility in healthy individuals is affected by impaired cerebral venous outflow.

PURPOSE: To investigate cerebrospinal fluid (CSF) dynamics in the aqueduct of Sylvius (AoS) in chronic cerebrospinal venous insufficiency (CCSVI)-positive and -negative healthy individuals using cine phase contrast imaging. MATERIALS AND METHODS: Fifty-one healthy individuals (32 CCSVI-negative and 19 age-matched CCSVI-positive subjects) were examined using Doppler sonography (DS). Diagnosis of CCSVI was established if subjects fulfilled ≥2 venous hemodynamic criteria on DS. CSF flow and velocity measures were quantified using a semiautomated method and compared with clinical and routine 3T MRI outcomes. RESULTS: CCSVI was associated with increased CSF pulsatility in the AoS. Net positive CSF flow was 32% greater in the CCSVI-positive group compared with the CCSVI-negative group (P = 0.008). This was accompanied by a 28% increase in the mean aqueductal characteristic signal (ie, the AoS cross-sectional area over the cardiac cycle) in the CCSVI-positive group compared with the CCSVI-negative group (P = 0.021). CONCLUSION: CSF dynamics are altered in CCSVI-positive healthy individuals, as demonstrated by increased pulsatility. This is accompanied by enlargement of the AoS, suggesting that structural changes may be occurring in the brain parenchyma of CCSVI-positive healthy individuals.

The airborne transmission of viruses causes tight transmission bottlenecks.

The transmission bottleneck describes the number of viral particles that initiate an infection in a new host. Previous studies have used genome sequence data to suggest that transmission bottlenecks for influenza and SARS-CoV-2 involve few viral particles, but the general principles of virus transmission are not fully understood. Here we show that, across a broad range of circumstances, tight transmission bottlenecks are a simple consequence of the physical process of airborne viral transmission. We use mathematical modelling to describe the physical process of the emission and inhalation of infectious particles, deriving the result that that the great majority of transmission bottlenecks involve few viral particles. While exceptions to this rule exist, the circumstances needed to create these exceptions are likely very rare. We thus provide a physical explanation for previous inferences of bottleneck size, while predicting that tight transmission bottlenecks prevail more generally in respiratory virus transmission.

Efficacy of Air Cleaning Units for preventing SARS-CoV-2 and other hospital-acquired infections on medicine for older people wards: A quasi-experimental controlled before-and- after study.

BACKGROUND: Nosocomial infections are costly and airborne transmission is increasingly recognised as important for spread. Air Cleaning Units (ACUs) may reduce transmission but little research has focused on their effectiveness on open wards. AIM: Assess whether ACUs reduce nosocomial SARS-CoV-2, or other, infections on older adult inpatient wards. METHODS: Quasi-experimental before-after study on two intervention-control ward pairs in a UK teaching hospital. Infections were identified using routinely collected electronic health records data during one year of ACU implementation and the preceding year ("core study period"). Extended analyses included 6 months additional data from one ward pair following ACU removal. Hazard ratios (HR) were estimated through Cox regression controlling for age, sex, ward and background infection risk. Time the ACUs were switched on was also recorded for intervention ward 2. FINDINGS: ACUs were initially feasible but compliance reduced towards the end of the study (average operation in first vs second half of ACU time on intervention ward 2: 77% vs 53%). 8171 admissions >48hrs (6112 patients, median age 85yrs) were included. Overall, incidence of ward-acquired SARS-CoV-2 was 3.8%. ACU implementation was associated with a non-significant trend of lower hazard for SARS-CoV-2 infection (HR core study period 0.90, 95% CI 0.53, 1.52; extended study period 0.78, 95% CI 0.53, 1.14). Only 1.5% of admissions resulted in other notable ward-acquired infections. CONCLUSION: ACUs may reduce SARS-CoV-2 infection to a clinically-meaningfully degree. Larger studies could reduce uncertainty, perhaps using a cross-over design, and factors influencing acceptability to staff and patients should be further explored.

Venous hemodynamics in neurological disorders: an analytical review with hydrodynamic analysis.

Venous abnormalities contribute to the pathophysiology of several neurological conditions. This paper reviews the literature regarding venous abnormalities in multiple sclerosis (MS), leukoaraiosis, and normal-pressure hydrocephalus (NPH). The review is supplemented with hydrodynamic analysis to assess the effects on cerebrospinal fluid (CSF) dynamics and cerebral blood flow (CBF) of venous hypertension in general, and chronic cerebrospinal venous insufficiency (CCSVI) in particular.CCSVI-like venous anomalies seem unlikely to account for reduced CBF in patients with MS, thus other mechanisms must be at work, which increase the hydraulic resistance of the cerebral vascular bed in MS. Similarly, hydrodynamic changes appear to be responsible for reduced CBF in leukoaraiosis. The hydrodynamic properties of the periventricular veins make these vessels particularly vulnerable to ischemia and plaque formation.Venous hypertension in the dural sinuses can alter intracranial compliance. Consequently, venous hypertension may change the CSF dynamics, affecting the intracranial windkessel mechanism. MS and NPH appear to share some similar characteristics, with both conditions exhibiting increased CSF pulsatility in the aqueduct of Sylvius.CCSVI appears to be a real phenomenon associated with MS, which causes venous hypertension in the dural sinuses. However, the role of CCSVI in the pathophysiology of MS remains unclear.

Changes of cine cerebrospinal fluid dynamics in patients with multiple sclerosis treated with percutaneous transluminal angioplasty: a case-control study.

PURPOSE: To investigate characteristics of cine phase contrast-calculated cerebrospinal fluid (CSF) flow and velocity measures in patients with relapsing-remitting (RR) multiple sclerosis (MS) receiving standard medical treatment who had been diagnosed with chronic cerebrospinal venous insufficiency (CCSVI) and underwent percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: This case-controlled, magnetic resonance (MR) imaging-blinded study included 15 patients with RR MS who presented with significant stenoses (≥50% lumen reduction on catheter venography) in the azygous or internal jugular veins. Eight patients underwent PTA in addition to medical therapy immediately following baseline assessments (case group) and seven had delayed PTA after 6 months of medical therapy alone (control group). CSF flow and velocity measures were quantified over 32 phases of the cardiac cycle by a semiautomated method. Outcomes were compared between groups at baseline and at 6 and 12 months of the study by mixed-effect model analysis. RESULTS: At baseline, no significant differences in CSF flow or velocity measures were detected between groups. At month 6, significant improvement in flow (P<.001) and velocity (P = .013) outcomes were detected in the immediate versus the delayed group, and persisted to month 12 (P = .001 and P = .021, respectively). Within-group flow comparisons from baseline to follow-up showed a significant increase in the immediate group (P = .033) but a decrease in the delayed group (P = .024). Altered CSF flow and velocity measures were associated with worsening of clinical and MR outcomes in the delayed group. CONCLUSIONS: PTA in patients with MS with CCSVI increased CSF flow and decreased CSF velocity, which are indicative of improved venous parenchyma drainage.

Jugular venous reflux and brain parenchyma volumes in elderly patients with mild cognitive impairment and Alzheimer's disease.

BACKGROUND: To determine whether or not jugular venous reflux (JVR) is associated with structural brain parenchyma changes in individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS: 16 AD patients (mean (SD): 81.9 (5.8) years), 33 MCI patients (mean (SD): 81.4 (6.1) years) and 18 healthy elderly controls (mean (SD): 81.5 (3.4) years) underwent duplex ultrasonography and magnetic resonance imaging scans to quantify structural brain parenchyma changes. Normalized whole brain (WB), gray matter (GM) and white matter (WM) volumes were collected, together with CSF volume. RESULTS: JVR was strongly associated with increased normalized WB (p = 0.014) and GM (p = 0.002) volumes across all three subject groups. There was a trend towards increased WB and GM volumes, which was accompanied by decreased CSF volume, in the JVR-positive subjects in both the MCI and AD groups. When the MCI and AD subjects were aggregated together significant increases were observed in both normalized WB (p = 0.009) and GM (p = 0.003) volumes for the JVR-positive group. No corresponding increases were observed for the JVR-positive subjects in the control group. Through receiver operating characteristic analysis of the brain volumetric data it was possible to discriminate between the JVR-positive and negative AD subjects with reasonable accuracy (sensitivity = 71.4%; specificity = 88.9%; p = 0.007). CONCLUSIONS: JVR is associated with intracranial structural changes in MCI and AD patients, which result in increased WB and GM volumes. The neuropathology of this unexpected and counterintuitive finding requires further investigation, but may suggest that JVR retrogradely transmits venous hypertension into the brain and leads to brain tissues swelling due to vasogenic edema.

Understanding adaptive gait in lower-limb amputees: insights from multivariate analyses.

BACKGROUND: In this paper we use multivariate statistical techniques to gain insights into how adaptive gait involving obstacle crossing is regulated in lower-limb amputees compared to able-bodied controls, with the aim of identifying underlying characteristics that differ between the two groups and consequently highlighting gait deficits in the amputees. METHODS: Eight unilateral trans-tibial amputees and twelve able-bodied controls completed adaptive gait trials involving negotiating various height obstacles; with amputees leading with their prosthetic limb. Spatiotemporal variables that are regularly used to quantify how gait is adapted when crossing obstacles were determined and subsequently analysed using multivariate statistical techniques. RESULTS AND DISCUSSION: There were fundamental differences in the adaptive gait between the two groups. Compared to controls, amputees had a reduced approach velocity, reduced foot placement distance before and after the obstacle and reduced foot clearance over it, and reduced lead-limb knee flexion during the step following crossing. Logistic regression analysis highlighted the variables that best distinguished between the gait of the two groups and multiple regression analysis (with approach velocity as a controlling factor) helped identify what gait adaptations were driving the differences seen in these variables. Getting closer to the obstacle before crossing it appeared to be a strategy to ensure the heel of the lead-limb foot passed over the obstacle prior to the foot being lowered to the ground. Despite adopting such a heel clearance strategy, the lead-foot was positioned closer to the obstacle following crossing, which was likely a result of a desire to attain a limb/foot angle and orientation at instant of landing that minimised loads on the residuum (as evidenced by the reduced lead-limb knee flexion during the step following crossing). These changes in foot placement meant the foot was in a different part of swing at point of crossing and this explains why foot clearance was considerably reduced in amputees. CONCLUSIONS: These results highlight that trans-tibial amputees use quite different gait adaptations to cross obstacles compared with controls (at least when leading with their prosthetic limb), indicating they are governed by different constraints; seemingly related to how they land on/load their prosthesis after crossing the obstacle.

A machine learning approach to identify important variables for distinguishing between fallers and non-fallers in older women.

Falls are a significant ongoing public health concern for older adults. At present, few studies have concurrently explored the influence of multiple measures when seeking to determine which variables are most predictive of fall risks. As such, this cross-sectional study aimed to identify those functional variables (i.e. balance, gait and clinical measures) and physical characteristics (i.e. strength and body composition) that could best distinguish between older female fallers and non-fallers, using a machine learning approach. Overall, 60 community-dwelling older women (≥65 years), retrospectively classified as fallers (n = 21) or non-fallers (n = 39), attended three data collection sessions. Data (281 variables) collected from tests in five separate domains (balance, gait, clinical measures, strength and body composition) were analysed using random forest (RF) and leave-one-variable-out partial least squares correlation analysis (LOVO PLSCA) to assess variable importance. The strongest discriminators from each domain were then aggregated into a multi-domain dataset, and RF, LOVO PLSCA, and logistic regression models were constructed to identify the important variables in distinguishing between fallers and non-fallers. These models were used to classify participants as either fallers or non-fallers, with their performance evaluated using receiver operating characteristic (ROC) analysis. The study found that it is possible to classify fallers and non-fallers with a high degree of accuracy (e.g. logistic regression: sensitivity = 90%; specificity = 87%; AUC = 0.92; leave-one-out cross-validation accuracy = 63%) using a combination of 18 variables from four domains, with the gait and strength domains being particularly informative for screening programmes aimed at assessing falls risk.

Assessment of cerebral venous return by a novel plethysmography method.

BACKGROUND: Magnetic resonance imaging and echo color Doppler (ECD) scan techniques do not accurately assess the cerebral venous return. This generated considerable scientific controversy linked with the diagnosis of a vascular syndrome known as chronic cerebrospinal venous insufficiency (CCSVI) characterized by restricted venous outflow from the brain. The purpose of this study was to assess the cerebral venous return in relation to the change in position by means of a novel cervical plethysmography method. METHODS: This was a single-center, cross-sectional, blinded case-control study conducted at the Vascular Diseases Center, University of Ferrara, Italy. The study involved 40 healthy controls (HCs; 18 women and 22 men) with a mean age of 41.5 ± 14.4 years, and 44 patients with multiple sclerosis (MS; 25 women and 19 men) with a mean age of 41.0 ± 12.1 years. All participants were previously scanned using ECD sonography, and further subset in HC (CCSVI negative at ECD) and CCSVI groups. Subjects blindly underwent cervical plethysmography, tipping them from the upright (90°) to supine position (0°) in a chair. Once the blood volume stabilized, they were returned to the upright position, allowing blood to drain from the neck. We measured venous volume (VV), filling time (FT), filling gradient (FG) required to achieve 90% of VV, residual volume (RV), emptying time (ET), and emptying gradient (EG) required to achieve 90% of emptying volume (EV) where EV = VV - RV, also analyzing the considered parameters by receiver operating characteristic (ROC) curves and principal component mathematical analysis. RESULTS: The rate at which venous blood discharged in the vertical position (EG) was significantly faster in the controls (2.73 mL/second ± 1.63) compared with the patients with CCSVI (1.73 mL/second ± 0.94; P = .001). In addition, respectively, in controls and in patients with CCSVI, the following parameters were highly significantly different: FT 5.81 ± 1.99 seconds vs 4.45 ± 2.16 seconds (P = .003); FG 0.92 ± 0.45 mL/second vs 1.50 ± 0.85 mL/second (P < .001); RV 0.54 ± 1.31 mL vs 1.37 ± 1.34 mL (P = .005); ET 1.84 ± 0.54 seconds vs 2.66 ± 0.95 seconds (P < .001). Mathematical analysis demonstrated a higher variability of the dynamic process of cerebral venous return in CCSVI. Finally, ROC analysis demonstrated a good sensitivity of the proposed test with a percent concordant 83.8, discordant 16.0, tied 0.2 (C = 0.839). CONCLUSIONS: Cerebral venous return characteristics of the patients with CCSVI were markedly different from those of the controls. In addition, our results suggest that cervical plethysmography has great potential as an inexpensive screening device and as a postoperative monitoring tool.

Cine cerebrospinal fluid imaging in multiple sclerosis.

PURPOSE: To investigate cerebrospinal fluid (CSF) dynamics in the aqueduct of Sylvius in multiple sclerosis (MS) patients and healthy controls (HC) using cine phase contrast imaging. MATERIALS AND METHODS: In all, 67 MS patients (48 relapsing-remitting [RR] and 19 secondary-progressive [SP]), nine patients with clinically isolated syndrome (CIS), and 35 age- and sex-matched HC were examined. CSF flow and velocity measures were quantified using a semiautomated method and compared with clinical and magnetic resonance imaging (MRI) disease outcomes. RESULTS: Significantly decreased CSF net flow was detected in MS patients compared to HC (-3.7 vs. -7.1 µL/beat, P = 0.005). There was a trend for increased net positive flow between SP, RR, and CIS patients. Altered CSF flow and velocity measures were associated with more severe T1 and T2 lesion volumes, lateral and fourth ventricular volumes, and third ventricular width in MS and CIS patients (P < 0.01 for all). In CIS patients, conversion to clinically definite MS in the following year was related to decreased CSF net flow (P = 0.007). There was a trend between increased annual relapse rate and altered CSF flow/velocity measures in RRMS patients (P < 0.05). CONCLUSION: CSF flow dynamics are altered in MS patients. More severe clinical and MRI outcomes in RRMS and CIS patients relate to altered CSF flow and velocity measures.