Apparent diffusion coefficient in the analysis of prostate cancer: determination of optimal b-value pair to differentiate normal from malignant tissue

PurposeDetermining optimal b-value pair for differentiation between normal and prostate cancer (PCa) tissues.MethodsForty-three patients with diagnosis or PCa symptoms were included. Apparent diffusion coefficient (ADC) was estimated using minimum and maximum b-values of 0, 50, 100, 150, 200, 500 s/mm2 and 500, 800, 1100, 1400, 1700 and 2000s/mm2, respectively. Diagnostic performances were evaluated when Area-under-the-curve (AUC) > 95%.Results15 of the 35 b-values pair surpassed this AUC threshold. The pair (50, 2000 s/mm2) provided the highest AUC (96%) with ADC cutoff 0.89 × 10–³ mm²/s, sensitivity 95.5%, specificity 93.2% and accuracy 94.4%.ConclusionsThe best b-value pair was b = 50, 2000 s/mm2.     

Lymph node metastasis in head and neck squamous carcinoma: Efficacy of intravoxel incoherent motion magnetic resonance imaging for the differential diagnosis

PurposeTo evaluate the value of pure molecular diffusion(D), perfusion-related diffusion (D*), perfusion fraction (f) and apparent diffusion coefficient (ADC) based on intravoxel incoherent motion (IVIM) theory for differential diagnosis of metastatic lymph nodes (LNs) in head and neck squamous cell carcinoma(HNSCC).Materials and methods29 patients with HNSCC and 20 patients with lymph node hyperplasia (LNH) were enrolled in this retrospective study, underwent magnetic resonance (MR) examination. IVIM Diffusion-weighted imaging (IVIM-DWI) was performed with 13 b values. D, D*, f and ADC values were compared between two groups. The diagnostic value of ADC, D, D* and D·D* value were evaluated by Receiver operating characteristic (ROC) curve. Two radiologists measured D, D*, f and ADC values independently.Results33 malignant LNs in HNSCC group and 22 benign LNs in LNH group (minimum diameter, ≥5 mm) were successfully examined, ADC(P < 0.05), D (P < 0.01) and f (P < 0.01) were significantly lower in malignant LNs than that in benign LNs, whereas D* was significantly higher (P < 0.01). The area under the ROC curve (AUC) for D·D* was 0.983 and was larger than that for D* (0.952), D (0.78) and ADC (0.67).ConclusionOur results indicate that IVIM DWI is feasible in the diagnosis of LN metastasis. D was significantly decreased in malignant LNs reflected increased nuclear-to-cytoplasmic ratio tissue, and D* was significantly increased reflected increased blood vessel generation and parenchymal perfusion in malignant LNs.     

The prediction of the treatment response of cervical nodes using intravoxel incoherent motion diffusion-weighted imaging

PurposeTo investigate the predictive role of Intravoxel Incoherent Motion Diffusion-Weighted Imaging (IVIM-DWI) parameters on cervical nodal response to chemo-radiotherapy (CRT) of head and neck squamous cell carcinoma (HNSCC).Materials and methodsPatients with pathologically confirmed HNSCC were included in the present prospective study, having at least one positive cervical lymph node (LN). They received concomitant CRT and underwent three serial IVIM-DWI investigations: before, at mid-treatment and after treatment completion. Tissue diffusion coefficient D, perfusion-related diffusion coefficient D* and perfusion fraction f were calculated by a bi-exponential fit. The two-sided Mann–Whitney rank test was used to compare the imaging parameters of patients with regional failure (RF) and regional control (RC). A p value lower than 0.05 was considered to be statistically significant.ResultsThirty-four patients were accrued. Twenty-four out of 34 LN (70.6%) showed persistent RC after a median follow-up time of 27.6 months (range: 12.0–50.2 months), while ten cases of RF (29.4%) were confirmed with a median time of 6.8 months (range: 1.5–19.5 months). Patients with RC showed significantly lower pre-treatment D values compared to the RF patients (p = 0.038). At mid-treatment, the patients with RF showed significantly higher D values (p = 0.025), and exhibited larger percent reductions in f and the product D* × f from the baseline (p = 0.008 and <0.001, respectively). No additional information was provided by the examination at the end of treatment.ConclusionPre-treatment and mid-treatment IVIM-DWI showed potential for prediction of treatment response of cervical LN in HNSCC patients.     

Plantar flexor muscle weakness may cause stiff-knee gait

AimThe iterative simulation studies proclaim that plantar flexor (PF) muscle weakness is one of the contributors of stiff knee gait (SKG), although, whether isolated PF weakness generates SKG has not been validated in able-bodied people or individuals with neuromuscular disorders. The aim of the study was to investigate the effects of isolated PF muscle weakness on knee flexion velocity and SKG in healthy individuals.MethodTwenty able-bodied young adults (23 ± 3 years) participated in this study. Passive stretch (PS) protocol was applied until the PF muscle strength dropped 33.1% according to the hand-held dynamometric measurement. Seven additional age-matched able-bodies were compared with participants’ to discriminate the influence of slow-walking. All participants underwent 3D gait analysis before and after the PS. Peak knee flexion angle, range of knee flexion between toe-off and peak knee flexion, total range of knee-flexion, and time of peak knee flexion in swing were selected to describe SKG pattern.ResultsAfter PS, the reduction of plantar flexor muscle strength (33.14%) caused knee flexion velocity drop at toe-off (p = 0.008) and developed SKG pattern by decreasing peak knee flexion (p = 0.0001), range of knee flexion in early swing (p = 0.006), and total knee flexion range (p = 0.002). These parameters were significantly correlated with decreased PF velocity at toe-off (p = 0.015, p = 0.0001, p = 0.005, respectively). The time of peak knee flexion was not significantly different between before and after stretch conditions (p = 0.130).ConclusionsThese findings verified that plantar flexor weakness cause SKG pattern by completing three of SKG parameters. Any treatment protocol that weakens the plantar flexor muscle might impact the SKG pattern.     

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.     

Computed diffusion-weighted MR imaging for visualization of pancreatic adenocarcinoma: Comparison with acquired diffusion-weighted imaging

ObjectiveTo assess the feasibility of computed diffusion-weighted imaging (cDWI) in comparison with directly acquired DWI for visualizing pancreatic adenocarcinomas.Materials and methodsPatients with pancreatic adenocarcinoma underwent DWI at b-values of 0, 1000 (DWI₁₀₀₀), 1500 (DWI₁₅₀₀) and 2000 (DWI₂₀₀₀) s/mm². From DWIs at b-values of 0 and 1000 s/mm², we generated cDWIs at b-values of 1500 (cDWI₁₅₀₀) and 2000 (cDWI₂₀₀₀) s/mm². DWI findings of pancreatic adenocarcinomas (clear hyperintensity; hyperintensity with an unclear distal border; and isointensity), the image quality and the tumor to pancreas contrast ratio (CR) were compared between directly acquired DWI and cDWI.ResultsAmong the 63 included patients, clear hyperintense tumors were seen in 35 on DWI₁₀₀₀, 50 on DWI₁₅₀₀, 50 on cDWI₁₅₀₀, 53 on DWI₂₀₀₀ and 44 on cDWI₂₀₀₀. Incidence of clear hyperintense tumors was significantly higher on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P = 0.013). There was no significant difference in the incidence of clear hyperintense tumors between DWI₁₅₀₀ and cDWI₁₅₀₀ (P > 0.999), but a lower incidence was seen on cDWI₂₀₀₀ than on DWI₂₀₀₀ (P = 0.028). Image quality was lower on cDWI than on DWI at b-values of 1500 (P = 0.002) and 2000 s/mm² (P < 0.001). The tumor to distal pancreas CR was significantly higher on cDWI₂₀₀₀ than on cDWI₁₅₀₀ (P < 0.001), and on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P < 0.001). The cDWI showed a significantly higher tumor to distal pancreas CR than DWI at b-values of 1500 (P = 0.004) and 2000 s/mm² (P < 0.001).ConclusionscDWI₁₅₀₀ generated from b-values of 0 and 1000 s/mm² should be considered more effective than DWI₁₀₀₀ and at least as effective as DWI₁₅₀₀.     

Assessment of early renal allograft dysfunction with blood oxygenation level-dependent MRI and diffusion-weighted imaging

PurposeTo investigate blood oxygenation level-dependent (BOLD) MRI and diffusion-weighted imaging (DWI) at 3 T for assessment of early renal allograft dysfunction.Materials and methods34 patients with a renal allograft (early dysfunction, 24; normal, 10) were prospectively enrolled. BOLD MRI and DWI were performed at 3 T. R2* and apparent diffusion coefficient (ADC) values were measured in cortex and medulla of the allografts. Correlation between R2* or ADC values and estimated glomerular filtration rate (eGFR) was investigated. R2* or ADC values were compared among acute rejection (AR), acute tubular necrosis (ATN) and normal function.ResultsIn all renal allografts, cortical or medullary R2* and ADC values were moderately correlated with eGFR (P < 0.05). Early dysfunction group showed lower R2* and ADC values than normal function group (P < 0.05). AR or ATN had lower R2* values than normal allografts (P < 0.05), and ARs had lower cortical ADC values than normal allografts (P < 0.05). No significant difference of R2* or ADC values was found between AR and ATN (P > 0.05).ConclusionBOLD MRI and DWI at 3 T may demonstrate early functional state of renal allografts, but may be limited in characterizing a cause of early renal allograft dysfunction. Further studies are needed.     

Influence of iron oxide nanoparticles (Fe3O4) on erythrocyte photohemolysis via photofrin and Rose Bengal sensitization

BackgroundIron oxide (Fe₃O₄) nanoparticles (IO-NP) were recently employed in medical applications as a diagnostic tool and drug carrier. Photofrin (PF) is a photosensitizer that clinically is used in Photodynamic therapy (PDT).Study designThe photosensitivity of PF and Rose Bengal (RB) mixed with (IO-NP) on red blood cells (RBCs) lysis was investigated. Second, Photohemolysis for post-irradiation (delayed) and during irradiation (continuous) with PF, RB and IO-NP combinations at different concentrations was investigated. Third, the photohemolysis rate, relative lysis steepness and power-concentration dependant parameter were evaluated by modeling and fitting the data using Gompertz function and power law.MethodsRBCs were isolated from healthy male human volunteer. Washed cells (7.86 × 10⁶ cells/mm³) were incubated with PF only or with IO-NP for 45 min at 37 °C then irradiated to a range of temperatures (4–41 °C). CPH results were recorded and evaluated using Gompertz function.ResultsThe relative steepness of the photohemolysis curves was approximately independent on light dose for delayed irradiation. The presence of IO-NP increases the rupturing time for 50% of the RBCs. Photohemolysis rate for delayed irradiation using the power law, led to 1.7 and 2.3 power dependence, respectively, for PF only and PF mixed with IO-NP. The power dependence of continuous irradiation measurements showed inverse proportionality for different concentrations of IO-NP combined with 2 μg/ml PF concentration and 1.5 μg/ml for RB concentration.ConclusionPhotosensitization of RBC with PF or RB mixed with IO-NP inhibited rupturing erythrocyte membrane and therefore a consideration should be taken against their combination in clinical applications.     

肺癌短期重复扫描ADC值和IVIM参数值的测量可重复性

目的:前瞻性评估肺癌短期重复扫描的ADC值及体素内不相干运动(IVIM)参数值的测量可重复性.方法:27个肺癌患者(27个病灶)进行2次自由呼吸DWI(b=0,300,800 s/mm2)及IVIM(10个b值,b=0～1000 s/mm2)扫描(间隔30～60min).2名独立测量者分别在ADC图、IVIM图上通过勾勒病灶获得ADC均值和D、D*、f值.采用配对样本t检验(正态分布)或Wilcoxon检验(非正态分布)比较重复测量、不同测量者和重复扫描的误差.各参数值的测量者内可重复性、测量者间一致性以及两次扫描的测量可重复性采用组内相关系数(ICC)、组间变异系数(WCV)和Bland-Altman法评价.结果:重复测量和重复扫描所得ADC均值、IVIM参数值差异均无统计学意义(P＞0.05).所有参数显示出好的测量者内可重复性和测量者间一致性,除了D*(WCV＞30％).重复扫描D值的可重复性最佳(ICC为0.905、0.883,WCV为7.63％、8.46％),ADC值的可重复性较好(ICC为0.829、0.823,WCV为10.65％、11.13％),而D*和f的可重复性相对较差(ICC为0.639～0.802;WCV为39.50％～58.14％).结论:当运用DWI或IVIM来监测肺癌疗效时,若ADC值、D、D*和f值的变化分别小于21.81％、16.58％、113.95％和84.77％,则很可能是由测量误差引起.需要改进IVIM扫描技术和后处理算法,提高D*和f的测量可重复性.     

Knee loading patterns of the non-paretic and paretic legs during post-stroke gait

BackgroundPost-stoke gait disorders could cause secondary musculoskeletal complications associated with excessive repetitive loading. The study objectives were to 1) determine the feasibility of measuring common proxies for dynamic medial knee joint loading during gait post-stroke with external knee adduction (KAM) and flexion moments (KFM) and 2) characterize knee loading and typical load-reducing compensations post-stroke.MethodsParticipants with stroke (n = 9) and healthy individuals (n = 17) underwent 3D gait analysis. The stroke and healthy groups were compared with unpaired t-tests on peak KAM and peak KFM and on typical medial knee joint load-reducing compensations; toe out and trunk lean. The relationship between KAM and load-reducing compensations in the stroke group were investigated with Spearman correlations.ResultsMean (SD) values for KAM and KFM in the healthy group[KAM = 2.20 (0.88)%BW*ht; KFM = 0.64 (0.60)%BW*ht] were not significantly different from the values for the paretic [KAM = 2.64 (0.98)%BW*ht; KFM = 1.26 (1.13)%BW*ht] or non-paretic leg of the stroke group[KAM = 2.23(0.62)%BW*ht; KFM = 1.10 (1.20)%BW*ht]. Post hoc one sample t-tests revealed greater loading in stroke participants on the paretic (n = 3), non-paretic (n = 1) and both legs (n = 2) compared to the healthy group. The angle of trunk lean and the angle of toe out were not related to KAM in the stroke group.DiscussionMeasurement of limb loading during a gait post-stroke is feasible and revealed excessive loading in individuals with mild to moderate stroke compared to healthy adults. Further investigation of potential joint degeneration and pain due to repetitive excessive loading associated with post-stroke gait is warranted.     

A tri-exponential model for intravoxel incoherent motion analysis of the human kidney: In silico and during pharmacological renal perfusion modulation

In the kidneys, there is both blood flow through the capillaries and flow of pre-urine through the tubuli and collecting ducts. We hypothesized that diffusion-weighted (DW) MRI measures both blood and pre-urine flow when using a tri-exponential intravoxel incoherent motion (IVIM) model. Our aim was to systematically investigate and optimize tri-exponential IVIM-analysis for the kidney and test its sensitivity to renal perfusion changes in humans.The tri-exponential fit probes the diffusion coefficient (D), the intermediate (D*_i) and fast (D*_f) pseudo-diffusion coefficients, and their signal fractions, f_D, f_i and f_f. First, we studied the effects of fixing the D*-coefficients of the tri-exponential fit using in silico simulations. Then, using a 3T MRI scanner, DW images were acquired in healthy subjects (18–24 years) and we assessed the within-subject coefficient of variation (wsCV, n = 6). Then, renal perfusion was modulated by Angiotensin II infusion during which DW imaging of the kidneys and phase contrast MRI of the renal artery was performed (n = 8). Radioisotope clearing tests were used to assess the glomerular filtration rate.Simulations showed that fixing the D*-coefficients - which could potentially increase the fit stability - in fact decreased the precision of the model. Changes in D*-coefficients were translated into the f-parameters instead. Fixing D*-coefficients resulted in a stronger response of the fit parameters to the intervention. Using this model, the wsCVs for D, f_D, f_i and f_f were 2.4%, 0.8%, 3.5%, 19.4% respectively. f_i decreased by 14% (p = 0.059) and f_f increased by 32% (p = 0.004) between baseline and maximal Angiotensin II dose. f_f inversely correlated to renal plasma flow (R = −0.70, p < 0.01) and f_i correlated to glomerular filtration rate (R = 0.39, p = 0.026).We validated a kidney-specific method for IVIM analysis using a tri-exponential model. The model is able to track renal perfusion changes induced by Angiotensin II.     

Combining dental and skeletal evidence in age classification: Pilot study in a sample of Italian sub-adults

BackgroundDental and skeletal maturation have proved to be reliable evidence for estimating age of children and prior studies and internationally accredited guidelines recommend to evaluate both evidence in the same subject to reduce error in age prediction. Nevertheless the ethical and legal justification of procedures that imply a double exposition of children stands as a relevant issue. This study aims to evaluate the accuracy of age estimation provided by a combination of skeletal and dental methods applied in the same sample of children.Materials and methodsThe sample consisted of 274 orthopantomographies and left hand-wrist X-rays of Italian children, (aged between 6 and 17 years) taken on the same day. Greulich and Pyle’s (GP), Tanner-Whitehouse’s version 3 (TW3) and Willems’ (W) and the Demirjian’s (D) methods were respectively applied for estimating skeletal and dental age. A combination of skeletal and dental age estimates through Linear Discriminant Analysis (LDA) is proposed to obtain a classifier respect to an age threshold.ResultsThe combination of D and TW3 obtained an improvement of accuracy in classifying female subjects respect to the 12 years threshold respect to the original methods (from about 77% using either original methods to 83.3% combining TW3 + D) as well as a consistent reduction of false positives rate (from 17% to 21% for original methods to 5.6% with TW3 + D). For males the LDA classifier (based on TW3 and W) enable a small improvement in accuracy, whilst the decreasing of false positives was as noticeable as for females (from 17.6 to 14.1% for original methods to 6.2% combining TW3 + W).ConclusionsAlthough the study is influenced by the limited size and the uneven age distribution of the sample, the present findings support the conclusion that age assessment procedures based on both dental and skeletal age estimation can improve the accuracy and reduce the occurrence of false positives.     

Reallocating time spent in physical activity intensities: Longitudinal associations with physical fitness (DADOS study)

ObjectivesFirstly, to investigate the longitudinal associations between accelerometer-derived physical activity (PA) intensities and physical fitness (PF) at 24-month follow-up in adolescents. Secondly, to examine how substituting time spent in low or moderate PA intensities with vigorous PA at baseline was related to PF at 24-month follow-up.DesignLongitudinal observational studyMethodThe DADOS (Deporte, ADOlescencia y Salud) study is a 3-year longitudinal research project carried out between years 2015–2017. The analyses included 189 adolescents (91 girls) aged 13.9 ± 0.3 years at baseline. PA was assessed by a wrist-worn GENEActiv triaxial accelerometer and expressed as minutes/day of light, moderate and vigorous PA. Cardiorespiratory, musculoskeletal and motor fitness were assessed by field tests and a global fitness z-score was calculated as the mean of the z-scores values of each fitness test. Association between PA intensities and PF were determined using linear regression. Isotemporal analyses estimating the association of reallocating PA intensities with PF were performed.ResultsBaseline vigorous PA was positively associated with cardiorespiratory fitness and global fitness score at follow-up in boys (β = 0.234;p = 0.002, β = 0.340;p < 0.001) and girls (β = 0.184;p = 0.043, β = 0.213;p = 0.004). In boys, baseline vigorous PA was also positively associated with musculoskeletal and motor fitness (β = 0.139;p = 0.035, β = 0.195;p = 0.021). The substitution of 10 min/day of light PA or moderate PA with 10 min/day of vigorous PA at baseline was positively associated with all PF components and global fitness score in boys (p < 0.001), and with global fitness score girls (p < 0.05).ConclusionThese findings highlight the need of promoting vigorous PA due to its specific influence on adolescent's PF.     

Homogeneity and reproducibility of in vivo fascicle length and pennation determined by ultrasonography in human vastus lateralis muscle

IntroductionEvaluate reliability of ultrasound measure to estimate muscle architecture.Methods and resultsUltrasound measurements were performed on the vastus lateralis muscle of 19 subjects. Test-retest measurements were performed at 10° and 100° of knee flexion, at rest and at 40% of MVC. Muscle thickness (MT) was measured on both sides and at the centre of the image. The fascicle pennation angle (θ) was estimated as the angle between a fascicle and the deep aponeurosis and as the average of the two angles between the same fascicle and its insertion into the aponeuroses. Fascicle length (FL) was estimated under the assumption of linearity as FL = M T * sin θ⁻¹. The most important factor influencing the measurement reproducibility of the pennation angle (θ) was the knee joint angle. For MT, reproducibility was higher during contraction at 10° of knee flexion. The different methods of estimation provided a good level of reproducibility for θ and MT. The estimation of the fascicle length was better for a 10° knee joint angle at 40% of MVC.ConclusionReproducibility of muscle architecture from ultrasonic measurements was better for a shortened position and contracted muscle, but poorly or not influenced by the method of calculation.     

R2*-relaxometry of the pancreas in patients with human hemochromatosis protein associated hereditary hemochromatosis

PurposeTo evaluate pancreatic iron in patients with human hemochromatosis protein associated hereditary hemochromatosis (HHC) using R2* relaxometry.Materials and methods81 patients (58 male, 23 female; median age 49.5, range 10–81 years) with HHC were retrospectively studied. All underwent 1.5 T magnetic resonance imaging (MRI) of the abdomen. A fat-saturated multi-gradient echo sequence with 12 echoes (TR = 200 ms; TE-initial 0.99 ms; Delta-TE 1.41 ms; 12 echoes; flip-angle: 20°) was used for the R2* quantification of the liver and the pancreas. Parameter maps were analyzed using regions of interest (3 in the liver and 2 in the pancreas) and R2* values were correlated.Results59/81 patients had a liver R2* ≥ 70 1/s of which 10/59 patients had a pancreas R2* ≥ 50 1/s. No patient presented with a liver R2* < 70 1/s and pancreas R2* ≥ 50 1/s. All patients with pancreas R2* values ≥ 50 1/s had liver R2* values ≥ 70 1/s. ROC analysis resulted in a threshold of 209.4 1/s for liver R2* values to identify HFE positive patients with pancreas R2* values ≥ 50 1/s with a median specificity of 78.87% and a median sensitivity of 90%.ConclusionIn patients with HHC R2* relaxometry of the pancreas should be performed when liver iron overload is present and can be omitted in cases with no sign of hepatic iron.     

Comparison of T2* relaxation times of articular cartilage of the knee in elite professional football players and age-and BMI-matched amateur athletes

ObjectiveRecent investigation has underlined the potential of quantitative MR imaging to be used as a complementary tool for the diagnosis of cartilage degeneration at an early state. The presented study analyses T2* relaxation times of articular cartilage of the knee in professional athletes and compares the results to age- and BMI (Body Mass Index)-matched healthy amateur athletes.Materials and methods22 professional football players and 22 age- and BMI-matched individuals were underwent knee Magnetic Resonance Imaging (MRI) at 3T including qualitative and quantitative analysis. Qualitative analysis included e.g. meniscal tears, joint effusion and bone edema. For quantitative analysis T2* (22 ET: 4.6-53.6 ms) measurements in 3D data acquisition were performed. Deep and superficial layers of 22 predefined cartilage segments were analysed. All data sets were postprocessed using a dedicated software tool. Statistical analysis included Student t-test, confidence intervals and a random effects model.ResultsIn both groups, T2* relaxation times were significantly higher in the superficial compared to the deep layers (p < 0.001). Professional athletes had significantly higher relaxation times in eight superficial and three deep cartilage layers in the predefined cartilage segments (p < 0.05). Highly significant differences were found in the weight-bearing segments of the lateral superficial femoral condyle (p < 0.001).ConclusionElevated T2* values in cartilage layers of professional football players compared to amateur athletes were noted. The effects seem to predominate in superficial cartilage layers.     

Stature estimation based on radial and ulnar lengths using three-dimensional images from multidetector computed tomography in a Japanese population

The aim of our study was to evaluate correlations between cadaver stature (CS) and radial and ulnar lengths based on three-dimensional (3D) computed tomography (CT) images, and to develop modern regression equations for estimating CS in a Japanese population. Measurements were performed on 245 Japanese subjects (123 males and 122 females) who underwent postmortem CT between May 2011 and December 2013. A 3D reconstructed image was used for assessment. The linear distances of the left radial (LR) and right radial (RR) lengths were measured as a straight-line distance from the most anteroproximal point of the head to the most distal end of the styloid process. The linear distances of the left ulnar (LU) and right ulnar (RU) lengths were measured as a straight-line distance from the most posteroproximal point of the olecranon to the most distal end of the styloid process. The correlation between CS and each parameter (LR, LU, RR, and RU) was assessed using Pearson product-moment correlation coefficients and regression analysis was performed for stature estimation. There were significant correlations between CS and each parameter regardless of sex, indicating that the radial and ulnar lengths measured on 3D CT images can be predictive of stature estimation. Simple regression equations for stature estimation calculated from LR provided the lowest standard error of estimation (SEE) (all subjects, SEE = 4.18 cm; males, SEE = 4.09 cm; females, SEE = 4.21 cm). In addition, multiple regression equations were more accurate and reliable than the single linear regression equations.     

Left and right atrial feature tracking in acute myocarditis: A feasibility study

PurposeThe present study aims at evaluating the feasibility and reproducibility of cardiac magnetic resonance (CMR) feature tracking (FT) derived strain and strain rate (SR) parameters of the left and right atrium (LA, RA) in patients with acute myocarditis as well as their potential to detect diastolic dysfunction. In addition, the diagnostic value of LA and RA strain parameters in the setting of acute myocarditis is investigated.MethodsCMR cine data of 30 patients with CMR-positive acute myocarditis were retrospectively analyzed. 25 age- and gender-matched healthy individuals served as a control. Analysis of longitudinal strain and SR of both atria was performed in two long-axis views using a dedicated FT-software. LA and RA deformation was analyzed including reservoir function (total strain [ε_s], peak positive SR [SR_s]), conduit function (passive strain [ε_e], peak early negative SR [SR_e]) and booster pump function (active strain [ε_a], peak late negative SR [SR_a]). Intra- and inter-observer reproducibility was assessed for all strain and SR parameters using Bland-Altman analyses, intra-class correlation coefficients (ICCs) and coefficients of variation (CV).ResultsFT analyses of both atria were feasible in all patients and controls. Reproducibility was good for reservoir and conduit function parameters and moderate for booster pump function parameters. Myocarditis patients demonstrated an impaired LA reservoir and conduit function when compared to healthy controls (LA ε_s: 32 ± 17 vs. 46 ± 13, p = 0.019; LA SR_s: 1.5 ± 0.5 vs. 1.8 ± 0.5, p = 0.117; LA SR_e: −1.3 ± 0.5 vs. −1.9 ± 0.5, p < 0.001), while LA booster pump function was preserved. In logistic regression and ROC-analyses, LA SR_e proved to be the best independent predictor of acute myocarditis (AUC 0.80), and using LA SR_e with a cut-off of −1.6 s⁻¹ resulted in a diagnostic sensitivity of 83% and a specificity of 80%. Changes in RA phasic function parameters showed a tendency to parallel those of the LA and showed no additional effect with respect to the diagnostic potential in acute myocarditis.ConclusionsMyocarditis patients exhibit an impaired atrial reservoir and conduit function, what might be indicative of ventricular diastolic dysfunction. LA SR_e was the best predictor for the presence of acute myocarditis in our study, pointing towards the discriminative power of atrial strain analysis in the CMR-based diagnosis of acute myocarditis.     

Physical fitness predicts adiposity longitudinal changes over childhood and adolescence

ObjectivesThe purpose of this study was to examine the influence of physical fitness (PF) on the development of subcutaneous adipose tissue in children followed longitudinally over a 9 year period ranging from childhood to adolescence.DesignThis longitudinal study followed 518 healthy participants (262 boys, 256 girls) over a 9-year period ranging from childhood (age 6) to adolescence (age 15). Adiposity (triceps and subscapular skinfolds), and fitness (60 s sit-ups, flexed arm hang, standing long jump, 50 m dash, 10 m shuttle run, sit-and-reach, and 20 m pacer run) were assessed at four annual time points during primary school, and on a follow up, 6 years later, during secondary school.MethodsGrowth in subcutaneous fat was modeled within a HLM statistical framework, using fitness components as time changing predictors.ResultsFlexed arm hang (β = ?0.059; p = 0.000), standing long jump (β = ?0.072; p = 0.000), 60 s sit-ups (β = ?0.041; p = 0.040), 50 m dash (β = 0.956; p = 0.000), and 20 m PACER (β = ?0.077; p = 0.000) tests, were found to predict changes on body fat growth over the years, independently of sex.ConclusionsImproving PF individual levels can positively influence adiposity deposition over the time period covering childhood and adolescence. That occurs independently of the typical sex differentiated adiposity growth.     

Validity and test-retest reliability of the Stride Analyzer in people with knee osteoarthritis

IntroductionSubjects with knee osteoarthritis walk differently compared to healthy subjects. Managing these gait alterations has been proven effective for reducing pain and increasing function. The Stride Analyzer is a low cost gait analysis tool but its clinimetric properties have not been investigated yet in subjects with symptomatic knee osteoarthritis. The aim of this study was to investigate the reliability and validity of the SA compared with the Gold standard (Vicon) in persons with knee OA.MethodsFifteen subjects with symptomatic knee osteoarthritis were instructed to walk at a self-selected speed in a gait laboratory. Temporospatial (TS) gait parameters were recorded simultaneously by the Stride Analyzer and by a 16-camera-infrared optoelectronic motion capturing system (Vicon). Validity and test-retest reliability of the Stride Analyzer were examined by Bland-Altman plots, intra-class correlation coefficients (ICC) and the standard error of measurement (SEM).ResultsTest-retest analyses showed good agreement for all TS parameters with ICC values ranging from 0.805 (single limb support right) to 0.949 (velocity) and SEM% values ranging from 0.78% (stance phase right (% of gait cycle)) to 4.52% (double limb support right (% of gait cycle)). Good agreement between Stride Analyzer and Vicon was found for the following TS parameters: velocity (z = 1.01), cadence (z = −0.85), stride length (z = 1.63) and gait cycle (z = 0.86). All other gait parameters showed lower ICC values (<0.689).InterpretationOur results suggest that the Stride Analyzer can be used in the clinical field to perform gait analysis in subjects with symptomatic knee osteoarthritis.