Running mechanics adjustments to perceptually-regulated interval runs in hypoxia and normoxia

ObjectivesWe determined whether perceptually-regulated, high-intensity intermittent runs in hypoxia and normoxia induce similar running mechanics adjustments within and between intervals.DesignWithin-participants repeated measures.MethodsNineteen trained runners completed a high-intensity intermittent running protocol (4 × 4-min intervals at a perceived rating exertion of 16 on the 6–20 Borg scale, 3-min passive recoveries) in either hypoxic (FiO₂ = 0.15) or normoxic (FiO₂ = 0.21) conditions. Running mechanics were collected over 10 consecutive steps, at constant velocity (∼15.0 ± 2.0 km.h⁻¹), at the beginning and the end of each 4-min interval. Repeated measure ANOVA were used to assess within intervals (onset vs. end of each interval), between intervals (interval 1, 2, 3 vs. 4) and FiO₂ (0.15 vs. 0.21) main effects and any potential interaction.ResultsParticipants progressively reduced running velocity from interval 1–4, and more so in hypoxia compared to normoxia for intervals 2, 3 and 4 (P < 0.01). There were no between intervals (across all intervals P > 0.298) and FiO₂ (across all intervals P > 0.082) main effects or any significant between intervals × within intervals × FiO₂ interactions (all P > 0.098) for any running mechanics variables. Irrespective of interval number or FiO₂, peak loading rate (+10.6 ± 7.7%; P < 0.001) and duration of push-off phase (+2.0 ± 3.1%; P = 0.001) increased from the onset to the end of 4-min intervals, whereas peak push-off force decreased (−4.0 ± 4.0%; P < 0.001).ConclusionsWhen carrying out perceptually-regulated interval treadmill runs, runners adjust to progressively slower velocities in hypoxia compared to normoxia. However, only subtle constant-velocity modifications of their mechanical behaviour occurred within each set, independently of FiO₂ or interval number.     

Aluminium salt-based antiperspirant coated prosthesis liners do not suppress local sweating during moderate intensity exercise in hot and temperate conditions

ObjectiveTo determine whether coating prosthesis liners with a 5% aluminium zirconium tetrachlorohydrate antiperspirant solution (AZCH) reduces local sweating on the thigh.DesignDouble-blinded counter-balanced crossover designMethodsFourteen able-bodied participants (age: 28 ± 5 y; body mass: 73.9 ± 7.9 kg, height: 1.73 ± 0.09 m; peak oxygen consumption [VO_2peak]: 50.7 ± 9.1 mlO₂⋅ kg⁻¹⋅ min⁻¹) simultaneously wore a prosthesis liner on each leg, one treated with AZCH and one untreated, for four days prior to running at 50% of VO_2peak for 60 min in a temperate (23.7 ± 0.7 °C and 42.2 ± 2.6% relative humidity) or hot (34.0 ± 1.6 °C and 40.8 ± 6.1% relative humidity) environment. Rectal temperature (T_re) and whole-body sweat rates (WBSR) were measured to characterize thermal strain. Local sweat rate (LSR) was measured bilaterally underneath the liners, continuously, and heat-activated-sweat gland density (HASGD) was measured bilaterally every 15 min.ResultsIn temperate condition, the mean change in T_re was 1.2±0.4 °C and WBSR was 723 ± 129 g⋅ h⁻¹, whereas in the hot condition, change in T_re was 1.2±0.5 °C and WBSR was 911 ± 231 g⋅ h⁻¹. In the temperate condition, AZCH treatment did not alter LSR (treated: 0.50±0.17 mg·cm^–2 min^–1, untreated: 0.50±0.17 mg·cm^–2 min^–1; P = 0.87) or HASGD (treated: 54±14 glands·cm^–2, untreated 55±14 glands·cm^–2; P = 0.38). In the hot condition, AZCH treatment paradoxically increased LSR (treated: 0.88 ± 0.38 mg·cm^–2 min^–1, untreated: 0.74 ± 0.28 mg·cm^–2 min^–1; P = 0.04) but not HASGD (treated: 52 ± 17 glands·cm^–2, untreated: 48 ± 19 glands·cm^–2; P = 0.77).ConclusionThese results indicate coating prosthesis liners with 5% AZCH is ineffective at reducing local sweating.     

Tattoos do not affect exercise-induced localised sweat rate or sodium concentration

ObjectivesSkin tattoos have been shown to reduce localised sweat rate and increase sweat sodium concentration ([Na⁺]) when sweating is artificially stimulated. This study investigated whether similar responses are observed with exercise-induced sweating.DesignUnblinded, within-participant control, single trial.MethodsTwenty-two healthy individuals (25.1 ± 4.8 y (Mean ± SD), 14 males) with a unilateral tattoo ≥11.4 cm² in size, ≥2 months in age, and shaded ≥50% participated in this investigation. Participants undertook 20 min of intermittent cycling (4 × 5 min intervals) on a stationary ergometer in a controlled environment (24.6 ± 1.1 °C; 64 ± 6% RH). Resultant sweat was collected into absorbent patches applied at two pairs of contralateral skin sites (pair 1: Tattoo vs. Non-Tattoo; pair 2: Control 1 vs. Control 2 (both non-tattooed)), for determination of sweat rate and sweat [Na⁺]. Paired samples t-tests were used to determine differences between contralateral sites.ResultsTattoo vs. Non-Tattoo: Neither sweat rate (Mean ± SD: 0.92 ± 0.37 vs. 0.94 ± 0.43 mg·cm⁻²·min⁻¹, respectively; p = 0.693) nor sweat [Na⁺] (Median(IQR): 37(32–52) vs. 37(31–45) mM·L⁻¹, respectively; p = 0.827) differed. Control 1 vs. Control 2: Neither sweat rate (Mean±SD: 1.19 ± 0.53 vs. 1.19 ± 0.53 mg·cm⁻²·min⁻¹, respectively; p = 0.917) nor sweat [Na⁺] (Median(IQR): 29(26–41) vs. 31(25–43) mM·L⁻¹, respectively; p = 0.147) differed. The non-significant differences for sweat rate and [Na⁺] between Tattoo vs. Non-Tattoo were inside the range of the within participant variability (sweat rate CVi = 5.4%; sweat [Na⁺] CVi = 4.4%).ConclusionsSkin tattoos do not appear to alter the rate or [Na⁺] of exercise-induced sweating. The influence of skin tattoos on localised sweat responses may have previously been over-estimated.     

Low intensity rowing with blood flow restriction over 5 weeks increases V̇O2max in elite rowers: A randomized controlled trial

ObjectivesThe present randomized controlled intervention study examined the effects of practical blood flow restriction (pBFR) on maximal oxygen uptake (V̇O₂max) during low intensity rowing.DesignThirty-one elite rowers were either assigned to the intervention (INT) or control (CON) group, using the minimization method (Strata: Gender, Age, Height, V̇O₂max).MethodWhile INT (n = 16; 4 female, 12 male, 21.9 ± 3.2 years, 180.4 ± 8.7 cm, 73.6 ± 10.9 kg, V̇O₂max: 63.0 ± 7.9 ml/min/kg) used pBFR during boat- and indoor-rowing training, CON (n = 15, 4 female, 11 male, 21.7 ± 3.7 years, 180.7 ± 8.1 cm, 72.5 ± 12.1 kg, V̇O₂max: 63.2 ± 8.5 ml/min/kg) completed the identical training without pBFR. pBFR of the lower limb was applied via customized elastic wraps. Training took place three times a week over 5 weeks (accumulated net pBFR: 60 min/week; occlusion per session: 2-times 10 min/session) and was used exclusively at low intensities (<2 mmol/L). A spiroergometric ramp test (V̇O₂max; 30–40 W/min increase) on rowing-ergometer and one-repetition maximum test of the squat exercise (SQ1RM) was employed to assess endurance and strength capacity.ResultsSignificant group × time interactions (η_p² = 0.26) in favor of INT were found for V̇O₂max (+9.1 ± 6.2%, Effect Size = 1.3) compared to CON (+2.5 ± 6.1%, ES = 0.3). SQ1RM (η_p² = 0.01) was not affected by the pBFR intervention.ConclusionsThis study revealed that 15 sessions of pBFR application with a cumulative total pBFR load of 5 h over a 5 weeks macrocycle remarkably increased V̇O₂max. Thus, pBFR might serve as a promising means to improve aerobic capacity in highly trained elite rowers.     

Effect of concentric and eccentric hamstring training on sprint recovery,strength and muscle architecture in inexperienced athletes

ObjectivesTo investigate whether five-weeks of concentric (CON) or eccentric (ECC) hamstring strength training have different effects on recovery from sprint running, eccentric strength and architecture of the biceps femoris long head (BF_LH).DesignCohort study.MethodsThirty males (age, 22.8 ± 4.1 y; height, 180.1 ± 6.4 cm; weight, 85.2 ± 14.6 kg) were allocated into either a CON or ECC group, both performing nine sessions of resistance training. Prior to and immediately after the five-week intervention, each participant’s BF_LH fascicle length (FL), pennation angle (PA), muscle thickness (MT), peak isometric KF torque and Nordic eccentric strength were assessed. Post-intervention, participants performed two timed sprint sessions (10 × 80 m) 48 h apart. Blood samples and passive KF torques were collected before, immediately after, 24 h and 48 h after the first sprint session.ResultsAfter five-weeks of strength-training, fascicles lengthened in the ECC (p < 0.001; d = 2.0) and shortened in the CON group (p < 0.001; d = 0.92), while PA decreased for the ECC (p = 0.001; d = 0.52) and increased in the CON group (p < 0.001; d = 1.69). Nordic eccentric strength improved in both ECC (p < 0.001; d = 1.49) and CON (p < 0.001; d = 0.95) groups. No between-group differences were observed in peak isometric strength (p = 0.480), passive KF torques (p = 0.807), sprint performance decrements between sprint sessions (p = 0.317) and creatine kinase (p = 0.818).ConclusionsDespite inducing significant differences in BF_LH muscle architecture, there were no significant between group differences in sprint performance decrements across two sprint sessions.     

Femoral torsion assessment with MRI in children: Should we use the bony or cartilaginous contours?

ObjectiveTo assess whether the use of cartilaginous contours at the femoral condyles instead of bony contours significantly changes femoral torsion measurements in children.Materials and MethodsFemoral torsion was measured in 32 girls (mean age 10.1 years ± 2.3 standard deviation) and 42 boys (10.9 years ± 2.5) on axial magnetic resonance (MR) images by two independent readers (R1,R2). The femoral condyle angle was measured using each the cartilaginous and bony contours of the distal femur. Cartilage thickness at femoral condyles was assessed. Intraclass-correlation-coefficient (ICC) and Pearson's correlation were used for statistical analysis.ResultsMean difference between cartilaginous and bony femoral torsion in girls was −1.1° ± 1.75 (range, −5.4° to 3.1°) for R1 and −1.64° ± 1.67 (−6.3° to 2.1°) for R2, in boys −1.5° ± 1.87 (−8.4° to 1.1°) for R1 and −2.28° ± 1.48 (−4.3° to 9.7°) for R2. Weak-to-moderate correlations between difference of cartilaginous-versus-bony measurements and cartilage thickness (r = −0.15 to −0.55, P < 0.001–0.46) or age (r = −0.33 to 0.46, P < 0.001–0.006) were found for both genders. Intermethod-ICC for cartilaginous versus bony femoral torsion measurements was 0.99/0.99 for R1/R2 in girls, and 0.99/0.98 in boys.ConclusionThere is only a small difference when measuring femoral torsion through cartilaginous versus bony contours, and no major difference in this between boys and girls.     

Dietary supplementation with New Zealand blackcurrant extract enhances fat oxidation during submaximal exercise in the heat

ObjectivesThis study investigated the effect of 7 days’ supplementation with New Zealand blackcurrant extract on thermoregulation and substrate metabolism during running in the heat.DesignRandomized, double-blind, cross-over study.MethodsTwelve men and six women (mean ± SD: Age 27 ± 6 years, height 1.76 ± 0.10 m, mass 74 ± 12 kg, V̇O_2max 53.4 ± 7.0 mL kg⁻¹ min⁻¹) completed one assessment of maximal aerobic capacity and one familiarisation trial (18 °C, 40% relative humidity, RH), before ingesting 2 × 300 mg day⁻¹ capsules of CurraNZ™ (each containing 105 mg anthocyanin) or a visually matched placebo (2 × 300 mg microcrystalline cellulose M102) for 7 days (washout 14 days). On day 7 of each supplementation period, participants completed 60 min of fasted running at 65% V̇O_2max in hot ambient conditions (34 °C and 40% relative humidity).ResultsCarbohydrate oxidation was decreased in the NZBC trial [by 0.24 g min⁻¹ (95% CI: 0.21–0.27 g min^-1)] compared to placebo (p =  0.014, d = 0.46), and fat oxidation was increased in the NZBC trial [by 0.12 g min⁻¹ (95% CI: 0.10 to 0.15 g min⁻¹)], compared to placebo (p = 0.008, d = 0.57). NZBC did not influence heart rate (p = 0.963), rectal temperature (p = 0.380), skin temperature (p = 0.955), body temperature (p = 0.214) or physiological strain index (p = 0.705) during exercise.ConclusionsSeven-days intake of 600 mg NZBC extract increased fat oxidation without influencing cardiorespiratory or thermoregulatory variables during prolonged moderate intensity running in hot conditions.     

Short term heat acclimation reduces heat strain during a first,but not second,consecutive exercise-heat exposure

ObjectivesDetermine whether five days of heat acclimation reduces cardiovascular and thermoregulatory strain during consecutive exercise-heat exposures on the sixth day in the heat.DesignPair-matched randomized control trial.MethodsTwenty-four males completed two, 120 min exercise sessions (Session 1, Session 2) in a single day before (Day 1) and after (Day 6) four additional days of exercise in either hot (HOT: 40 °C, 40% relative humidity, n = 16) or temperate (CON: 23 °C, 25% relative humidity, n = 8) environments. A mixed-methods heat acclimation approach was implemented. Day 2 consisted of 120 min of moderate-high intensity treadmill exercise. Days 3–5 consisted of 90 min of moderate-high intensity exercise, with HOT completing this in a hyperthermia clamped manner at rectal temperature ≥38.5 °C, and CON < 38.5 °C.ResultsSession 1 end of exercise rectal temperature and heart rate were lower on Day 6 compared to Day 1 for HOT (p = 0.012, p = 0.003) but not CON (p = 0.152, p = 0.437). Session 2 end of exercise rectal temperature was not different between days for HOT (p = 0.104) or CON (p = 0.275). Session 2 end of exercise heart rate was lower on Day 6 compared to Day 1 for HOT (p = 0.004) and CON (p = 0.039). Session 1 sweat sensitivity was greater on Day 6 compared to Day 1 for HOT (p = 0.039) but not CON (p = 0.257). Sweat rate was unchanged for HOT and CON between days during Session 1 (p = 0.184, p = 0.962) and Session 2 (p = 0.051, p = 0.793), respectively.ConclusionsFive days of heat acclimation reduced cardiovascular strain but not thermoregulatory strain during the second, consecutive exercise-heat exposure.ClinicalTrials.gov IdentifierNCT04053465.     

Effect of co-ligands on chemical and biological properties of 99mTc(III) complexes [99mTc(L)(CDO)(CDOH)2BMe] (L = Cl,F, SCN and N3; CDOH2 = cyclohexanedione dioxime)

Introduction^99mTc-Teboroxime ([^99mTcCl(CDO)(CDOH)₂BMe]) is a member of the BATO (boronic acid adducts of technetium dioximes) class of ^99mTc(III) complexes. This study sought to explore the impact of co-ligands on solution stability, heart uptake and myocardial retention of [^99mTc(L)(CDO)(CDOH)₂BMe] (^99mTc-Teboroxime: L = Cl; ^99mTc-Teboroxime(F): L = F; ^99mTc-Teboroxime(SCN): L = SCN; and ^99mTc-Teboroxime(N₃): L = N₃).MethodsRadiotracers ^99mTc-Teboroxime(L) (L = F, SCN and N₃) were prepared by reacting ^99mTc-Teboroxime with NaF, NaSCN and NaN₃, respectively. Biodistribution and imaging studies were carried out in Sprague–Dawley rats. Image quantification was performed to compare their heart retention and liver clearance kinetics.ResultsComplexes ^99mTc-Teboroxime(L) (L = F, SCN and N₃) were prepared in high yield with high radiochemical purity. All new radiotracers were stable for > 6 h in the kit matrix. In its HPLC chromatogram, ^99mTc-Teboroxime showed one peak at ~ 15.5 min, which was shorter than that of ^99mTc-Teboroxime(F) (~ 16.4 min). There were two peaks for ^99mTc-Teboroxime(SCN) at 16.5 and 18.3 min. ^99mTc-Teboroxime(N₃) appeared as a single peak at 18.4 min. Their heart retention and liver clearance curves were best fitted to the bi-exponential decay function. The half-times of fast/slow components were 1.6 ± 0.4/60.7 ± 8.9 min for ^99mTc-Teboroxime, 0.8 ± 0.2/101.7 ± 20.7 min for ^99mTc-Teboroxime(F), 1.2 ± 0.3/84.8 ± 16.6 min for ^99mTc-Teboroxime(SCN), and 2.9 ± 0.9/51.6 ± 5.0 min for ^99mTc-Teboroxime(N₃). The 2-min heart uptake followed the order of ^99mTc-Teboroxime (3.00 ± 0.37%ID/g) > ^99mTc-Teboroxime(N₃) (2.66 ± 0.01 %ID/g) ≈ ^99mTc-Sestamibi (2.55 ± 0.46 %ID/g) > ^99mTcN-MPO (2.38 ± 0.15 %ID/g). ^99mTc-Teboroxime remains the best in first-pass extraction. The best image acquisition window is 0–5 min for ^99mTc-Teboroximine and 0–15 min for ^99mTc-Teboroximine(N₃).ConclusionCo-ligands had significant impact on the heart uptake and myocardial retention of complexes [^99mTc(L)(CDO)(CDOH)₂BMe] (L = Cl, F, SCN and N₃). Future studies should be directed towards minimizing the liver uptake and radioactivity accumulation in the blood vessels while maintaining their high heart uptake.     

Difference in the craniocaudal gradient of the maximum pixel value change rate between chronic obstructive pulmonary disease patients and normal subjects using sub-mGy dynamic chest radiography with a flat panel detector system

ObjectivesTo compare the craniocaudal gradients of the maximum pixel value change rate (MPCR) during tidal breathing between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography.Materials and methodsThis prospective study was approved by the institutional review board and all participants provided written informed consent. Forty-three COPD patients (mean age, 71.6 ± 8.7 years) and 47 normal subjects (non-smoker healthy volunteers) (mean age, 54.8 ± 9.8 years) underwent sequential chest radiographs during tidal breathing in a standing position using dynamic chest radiography with a flat panel detector system. We evaluated the craniocaudal gradient of MPCR. The results were analyzed using an unpaired t-test and the Tukey–Kramer method.ResultsThe craniocaudal gradients of MPCR in COPD patients were significantly lower than those in normal subjects (right inspiratory phase, 75.5 ± 48.1 vs. 108.9 ± 42.0 s⁻¹ cm⁻¹, P < 0.001; right expiratory phase, 66.4 ± 40.6 vs. 89.8 ± 31.6 s⁻¹ cm⁻¹, P = 0.003; left inspiratory phase, 75.5 ± 48.2 vs. 108.2 ± 47.2 s⁻¹ cm⁻¹, P = 0.002; left expiratory phase, 60.9 ± 38.2 vs. 84.3 ± 29.5 s⁻¹ cm⁻¹, P = 0.002). No significant differences in height, weight, or BMI were observed between COPD and normal groups. In the sub-analysis, the gradients in severe COPD patients (global initiative for chronic obstructive lung disease [GOLD] 3 or 4, n = 26) were significantly lower than those in mild COPD patients (GOLD 1 or 2, n = 17) for both right and left inspiratory/expiratory phases (all P ≤ 0.005).ConclusionsA decrease of the craniocaudal gradient of MPCR was observed in COPD patients. The craniocaudal gradient was lower in severe COPD patients than in mild COPD patients.     

Perceived exertion responses to wheelchair propulsion differ between novice able-bodied and trained wheelchair sportspeople

ObjectivesTo investigate peripheral (RPE_P) and central (RPE_C) Ratings of Perceived Exertion during wheelchair propulsion in untrained able-bodied (AB) participants, and trained wheelchair rugby athletes with and without cervical spinal cord injury (CSCI).DesignCross-sectional study.Methods38 participants (AB: n = 20; wheelchair rugby athletes with CSCI: n = 9; without CSCI: n = 9) completed an incremental wheelchair propulsion test to exhaustion on a motorised treadmill. Gas exchange measures and heart rate (HR) were collected throughout. RPE_P and RPE_C on the Category Ratio-10 were verbally recorded each minute. Blood lactate concentration ([BLa]) was determined post-test.ResultsBetween 50–100% peak oxygen uptake (V̇O_2peak), RPE_P was greater than RPE_C in AB (p < 0.05), but not in athletes with (p = 0.07) or without (p = 0.16) CSCI. RPE_P was greater in AB compared to players with CSCI (Effect sizes: 1.24–1.62), as were respiratory exchange ratio (1.02 ± 0.10 vs 0.82 ± 0.11, p < 0.05) and [BLa]_peak (7.98 ± 2.53 vs 4.66 ± 1.57 mmol·L⁻¹). RPE_C was greater in athletes without CSCI compared to those with CSCI (Effect sizes: 0.70–1.38), as were HR (166 ± 20 vs 104 ± 15 beats·min⁻¹, p < 0.05) and ventilation (59.2 ± 28.8 vs 35.1 ± 16.6 L·min⁻¹, p = 0.01).ConclusionsRPE_P was dominant over RPE_C during wheelchair propulsion for untrained AB participants. For athletes with CSCI, lower RPE_P and RPE_C were reported at the same %V̇O_2peak compared to those without CSCI. The mechanism for this remains to be fully elucidated.     

Development and automation of a novel NET-PET tracer: [11C]Me@APPI

IntroductionThe norepinephrine transporter (NET) is an important target for research in neurology and psychology and is involved in the pathophysiology of many neurodegenerative diseases such as Alzheimer's disease and attention deficient hyperactivity disorder. For visualization of NET abundance and deregulation, a novel PET tracer – [¹¹C]Me@APPI – has been developed.MethodsFor precursor synthesis, a 4-step synthesis starting from N-phenyl-o-phenylenediamine was set up. Radiosynthesis was established and optimized using standard methods and subsequently automated in a GE TRACERlabFx C Pro synthesizer. Preclinical testing was performed comprising affinity and selectivity testing on human membranes as well as stability and blood–brain-barrier-penetration using in-vitro models.ResultsPrecursor molecule (APPI:0) and reference compound (Me@APPI) were synthesized with 26.5% and 21.4% overall yield, respectively. So far, 1.25 ± 0.72 GBq [¹¹C]Me@APPI with 54.35 ± 7.80 GBq/μmol specific activity were produced (n = 11). Affinity of reference compounds was determined as 8.08 ± 1.75 nM for Me@APPI and 19.31 ± 2.91 nM for APPI:0, respectively (n ≥ 9). IAM-chromatography experiments (n = 3) revealed a P_m value of 1.51 ± 0.34 for Me@APPI. Stability testing using human liver microsomes revealed that 99.5% of the tracer was found to be still intact after 60 minutes (n = 4).ConclusionPresent data indicate that [¹¹C]Me@APPI has promising properties to become a clinically useful NET-PET-tracer. Further in-vitro and in-vivo evaluations are currently under way.     

Correlation between intravoxel incoherent motion MR parameters and MR nodular grade of parotid glands in patients with Sjögren’s syndrome: A pilot study

PurposeTo explore the correlation between intravoxel incoherent motion (IVIM) magnetic resonance (MR) parameters and MR nodular grade of parotid glands in patients with Sjögren’s syndrome (SS).Materials and methodsA total of 31 consecutive patients with SS and 28 gender- and age-matched healthy volunteers underwent bilateral parotid 3.0T MR examination including the IVIM sequence (9 b values, 0–800 s/mm²). The apparent diffusion coefficient (ADC), diffusion coefficient D, pseudo-diffusion coefficient D^*, and perfusion fraction f of bilateral parotid glands were obtained, and the nodular grade of each parotid gland was evaluated according to the MR morphological appearance.ResultsSixty-two parotid glands in 31 patients with SS consisted of 32, 14, 8, and 8 parotid glands at MR nodular grades 0, 1, 2, and 3, respectively. In parotid glands of grade 0, 1, 2, 3 and healthy volunteers, the ADC values were (1.13 ± 0.25, 1.11 ± 0.17, 1.05 ± 0.24, 0.89 ± 0.04 and 1.00 ± 0.21) × 10⁻³ mm²/s, D values were (0.92 ± 0.13, 0.90 ± 0.19, 0.90 ± 0.03, 0.67 ± 0.03, 0.81 ± 0.03) × 10⁻³ mm²/s, f values were 0.20 ± 0.04, 0.18 ± 0.02, 0.15 ± 0.01, 0.11 ± 0.01, 0.15 ± 0.06, and D^*values were (53.89 ± 28.26, 41.78 ± 16.35, 51.24 ± 18.69, 31.83 ± 18.03, 36.83 ± 16.14) × 10⁻³ mm²/s respectively. The ADC, D, f, and D^* values of parotid glands in patients with SS at grade 0 were significantly higher than those in healthy volunteers (all P < 0.05). Significant differences were observed in the D and f values of parotid glands in patients with SS among different grades (P = 0.003, < 0.001, respectively). The IVIM parameters (D, f) of parotid glands at early (grades 0–1) and advanced (grades 2–3) stages in patients with SS were significantly higher and lower, respectively, than those in healthy volunteers (all P < 0.05). The D and f values inversely correlated with MR nodular grades significantly (r = − 0.297, P = 0.019; r = − 0.653, P < 0.001, respectively)ConclusionThe parotid glands with different MR nodular grades in patients with SS showed different IVIM parameters, reflecting different pathophysiological characteristics of parotid glands at different stages.     

Reproducibility and accuracy of ABC/2 and 3D techniques in ICH volume measurement

PurposeThe aims of this study were to validate 3D volume measurement and to compare ICH volume determined by conventional measurements.Materials and methodsData of all 50 patients were retrospectively collected. The ICH volume was compared using ABC/2 technique and 3D volumetric technique by two observers. Interobserver and intraobserver variations were calculated. Variability of measurements was analysed.ResultsThe mean volume was 41.43 ± 3.0 mm³ using 3D technique versus 45.37 ± 3.9 mm³ using ABC/2 technique. The coefficients of variation for interobserver and intraobserver variability of 3D and ABC/2 technique were 5.03% versus 6.28% and 2.78% versus 8.77%. ABC/2 technique generally overestimated ICH volume. The 95% confidence interval (CI) of 3D and ABC/2 technique was 29.4–53.5 mm³ and 32–58.6 mm³. There was no significance difference in volume measurement by variance ratio test (F-test), where p = 0.527. The correlation coefficient of ABC/2 and 3D method was 0.99 (p < 0.001, 95% CI 0.98–0.99). Box-and-whisker graph showed that ABC/2 technique generally overestimated the ICH volume with irregular margin.The results showed that (a) ICH volumes estimated by the ABC/2 technique do not significantly differ from 3D technique. (b) ABC/2 technique was accurate when estimating volume with regular margin but overestimated volume in irregular margin. (c) Reproducibility of 3D technique in ICH volume with irregular margin was higher. (d) Reproducibility of ABC/2 technique in ICH volume with regular margin was higher.Conclusions3D technique is the most reproducible technique. Although the ABC/2 technique slightly overestimates ICH volume with irregular margin, the difference was not significant. In view of the software requirement for 3D measurement, ABC/2 technique is considered a rapid and reliable volume measurement technique.     

Heart rate and blood lactate responses during Taekwondo training and competition

ObjectiveThe study investigated physical fitness characteristics of elite Taekwondo (TKD) players as well as their heart rate (HR) response and blood lactate concentration changes during TKD specific exercises and simulated competition.MethodsAnaerobic and aerobic power has been evaluated in eight elite TKD players (age: 20 ± 1 years, body mass: 70.8 ± 6 kg, Ht: 179.9 ± 4 cm). We also measured heart rate and blood lactate concentration during competition and specific-exercises (front kicks during 10 s, 1 and 3 min).ResultsMaximum oxygen uptake (VO₂max) and peak anaerobic power (Wpeak) averaged 56.22 ± 2.57 ml min^–1 kg^–1 and 12.1 ± 1.7 W kg^–1, respectively. HR and blood lactate [La] concentrations increased significantly during competition (F = 19.4, P < 0.001; F = 21.3, P < 0.001) compared to the resting value. HR and [La] values were significantly correlated with those measured during 10 s (R = 0.85, P < 0.05 and R = 0.79, P < 0.05, respectively) and 3-min specific exercises (R = 0.95, P < 0.01 and R = 0.76, P < 0.05).ConclusionsTKD requires high levels of both aerobic and anaerobic physical fitness. The correlation between specific exercises and competition is of practical interest for TKD players and trainers.     

Qualitative and quantitative analysis of diffusion-weighted imaging of gestational trophoblastic disease: Can it predict progression of molar pregnancy to persistent form of disease?

PurposeTo describe the diffusion-weighted imaging (DWI) appearance of gestational trophoblastic disease (GTD) and to determine its apparent diffusion coefficient (ADC) values. To evaluate the feasibility of DWI to predict progression of hydatidiform mole (HM) to persistent disease.MethodsDuring a period of 6 months, women with preliminary diagnosis of GTD, based on ultrasound and ßhCG levels, underwent 1.5T MRI (T2 high-resolution and DWI; b values 50, 400, 800; sagittal and perpendicular to the endometrium; and T1, T2 Turbo Spin Echo [TSE] axial images). Patients were followed for 6–12 months to monitor progression to persistent form of the disease. ADC values and image characteristics were compared between HM and persistent neoplasia and between GTD and non-molar pregnancy using Mann–Whitney U and Fisher’s exact tests, respectively.ResultsAmong the 23 studied patients, 19 (83%) were classified as molar and 4 (17%) as non-molar, based on pathology reports. After 6–12 months of follow-up, 5 (26%) cases progressed to persistent disease and 14 (74%) cases were benign HM. There was no significant difference between ADC values for HM (1.93 ± 0.33 × 10⁻³ mm²/s) and persistent neoplasia (2.03 ± 0.28 × 10⁻³ mm²/s) (P = 0.69). The ADC of non-molar pregnancies was (0.96 ± 0.46 × 10⁻³ mm²/s), which was significantly different from GTD (1.96  ± 0.32 × 10⁻³ mm²/s) (P = 0.001). Heterogeneous snowstorm appearance, focal intratumoral hemorrhage, myometrial contraction, and prominent myometrial vascularity were more common in GTD compared to non-molar pregnancy (P < 0.05).ConclusionHeterogeneous snowstorm appearance, focal intratumoral hemorrhage, myometrial contraction, and prominent myometrial vascularity are among the imaging characteristics of GTD. We cannot use ADC values to predict progression to persistent disease.     

Noise reduction angiographic imaging technology reduces radiation dose during bronchial artery embolization

PurposeComparison of radiation doses in patients undergoing angiographic bronchial artery embolization (BAE) before and after a noise reduction imaging technology upgrade.MethodsWe performed a retrospective study of 70 patients undergoing BAE. Procedures were performed before (n = 32) and after (n = 38) the technology upgrade containing additional filters and improved image-processing. Cumulative air kerma (AK), cumulative dose area product (DAP), number of exposure frames, total fluoroscopy time and amount of contrast agent were recorded. Mean values were calculated and compared using two-tailed t-tests. DSA image quality was assessed independently by two blinded readers and compared using the Wilcoxon signed-rank test.ResultsUsing the new technology resulted in a significant reduction of 59% in DAP (149.2 (103.1–279.1) vs. 54.8 (38.2–100.7) Gy*cm², p < 0.001) and a significant reduction of 60% for AK (1.3 (0.6-1.9) vs. 0.5 (0.3-0.9) Gy, p < 0.001) in comparison to procedures before the upgrade. There was no significant difference between the number of exposure frames in both groups (251 ± 181 vs. 254 ± 133 frames, p = 0.07), time of fluoroscopy (28.8 (18.5-50.4) vs. 28.1 (23.3–38.7) min, p = 0.73), or the amount of contrast agent used (139.5 ± 70.8 vs. 163.1 ± 63.1 ml, p = 0.11). No significant difference regarding image quality could be detected (3 (2,3) vs. 3 (2–4), p = 0.64).ConclusionsThe new angiographic noise reduction technology significantly decreases the radiation dose during bronchial artery embolization without compromising image quality or increasing time of fluoroscopy or contrast volume.