Absolute Cut-off Values Research Articles

P482 Diagnostic accuracy of contrast-enhanced ultrasound for fibrotic strictures of Crohn’s disease: a systematic review and meta-analysis of individual participant data

Abstract Background Crohn's disease (CD) often leads to the development of intestinal strictures, requiring effective differentiation between inflammatory and fibrotic for the optimal treatment strategies. Despite recent advances in drug development targeting fibrosis, current evaluation methods remain insufficient. Contrast-enhanced ultrasound (CEUS) is a promising modality for assessing vascularity and inflammation, yet its accuracy in fibrosis detection needs more validation. Methods A systematic review and meta-analysis were conducted using IPD to determine the diagnostic accuracy of CEUS in identifying intestinal fibrosis in CD. Our search included databases such as MEDLINE, EMBASE, and Web of Science up until March 23, 2023. Inclusion criteria required a confirmed diagnosis of CD and studies that evaluated the accuracy of CEUS parameters, including total area under the curve (AUC), wash-in AUC, wash-out AUC, peak enhancement, wash-in perfusion index, wash-in rate, wash-out rate, rise time, fall time, and mean transit time related to fibrosis in CD (Figure 1 (A)). The quality of included studies was assessed using the QUADAS-2 tool, with each study mandatorily using surgical specimen pathology as a reference standard in at least one instance. Results Our qualitative synthesis included eight studies encompassing 306 patients. These studies were generally assessed to have a high risk of bias. It is important to note that while peak enhancement and AUC were frequently examined across studies, neither parameter had established absolute cutoff values for the diagnosis of fibrosis. From the three studies where IPD was available, detailed data from 80 patients were included in the meta-analysis (colon n=11 and small bowel n= 69). Among them, 54 underwent surgical intervention with fibrosis being confirmed in 31. The highest diagnostic accuracy was observed for total AUC and wash-in AUC, with pooled sensitivity and specificity for predicting fibrosis at 0.86 (95% CI, 0.59–0.97) and 0.25 (95% CI, 0.03–0.76), respectively (Figure 1 (B)). Conclusion This meta-analysis with IPD pioneers the exclusive evaluation of CEUS for fibrotic strictures in CD. It reveals a significant risk of bias in the primary research and a notable absence of consensus on the CEUS parameters' threshold values for distinguishing fibrosis from inflammation. The observed low specificity highlights the need for innovative strategies in future research, such as integrating CEUS with techniques like elastography, to enhance the precision of fibrosis detection in CD. PROSPERO 2020 CRD42020214472. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020214472

How low can we (reliably) go? A method comparison of thyroid-stimulating hormone assays with a focus on low concentrations.

International guidelines concerning subclinical hyperthyroidism and thyroid cancer advice absolute cut-off values for aiding clinical decisions in the low range of thyroid-stimulating hormone (TSH) concentrations. As TSH assays are known to be poorly standardized in the normal to high range, we performed a TSH assay method comparison focusing on the low range. Sixty samples, selected to cover a wide range of TSH concentrations (<0.01 to 120 mIU/L) with oversampling in the lower range (<0.4 mIU/L), were used for the method comparison between three TSH immunoassays (Cobas, Alinity and Atellica). In addition, 20 samples were used to assess the coefficient of variation from duplicate measurements in these three methods. The TSH immunoassays showed standardization differences with a bias of 7-16% for the total range and 1-14% for the low range. This could lead to a different classification of 1.5% of all measured TSH concentrations <0.40 mIU/L measured in our laboratory over the last 6 months, regarding the clinically important cut-off value of TSH = 0.1 mIU/L. As the imprecision of the immunoassays varied from 1.6-5.5%, this could lead to a similar reclassification as the bias between immunoassays. We established the standardization differences of frequently used TSH assays for the total and low concentration ranges. Based on the proportional bias and the imprecision, this effect seems to have limited clinical consequences for the low TSH concentration range. Nevertheless, as guidelines mention absolute TSH values to guide clinical decision-making, caution must be applied when interpreting values close to these cut-offs.

Myocardial blood flow values based on 15O-water PET are insensitive to image reconstruction settings

Abstract Funding Acknowledgements Type of funding sources: None. Background For 15O-water PET, a cutoff hyperemic myocardial blood flow (MBF) value of 2.3 mL/g/min for significant ischemia has been established (1). For other tracers, different studies show a wide range of proposed cutoff values. The use of uniform absolute cutoff values for pathological hyperemic MBF or flow reserve in clinical decision making requires robust quantification of MBF, with comparable values across scanners, centres, and reconstruction methods. Purpose The aim of the present work was to assess the effect of different reconstruction methods on quantitative MBF values based on 15O-water PET. Methods 20 patients referred for assessment of ischemia underwent 4 min dynamic stress PET scans starting simultaneously with automated bolus injection of 400 MBq 15O-water on a digital PET/CT scanner. Images were reconstructed using 17 different reconstruction methods, with the clinical reconstruction used as reference: time-of-flight (TOF) ordered subsets expectation maximization (OSEM) with 3 iterations and 16 subsets, including point spread function recovery (PSF) and a 5 mm gaussian post-filter. Parameters that were varied were number of iterations (1-6), filter (3, 5 or 8 mm), exclusion of TOF and PSF, and using regularized reconstruction with 7 different values of the regularization parameter beta. Images were analyzed fully automatically using aQuant software, resulting in parametric MBF images and polar maps as well as regional MBF values. Correlation and agreement of MBF values based on each reconstruction were compared using regression and Bland-Altman analysis as well as Wilcoxon tests. Results Whole left ventricle MBF values ranged from 1.1 to 3.9 mL/g/min. Visually, there were only small differences in MBF images or polar maps between methods (Figure 1). Correlation between whole left ventricle MBF values based on the various reconstruction algorithms was high (r &amp;gt; 0.99). At the regional level, correlation coefficients were always &amp;gt; 0.94 (Figure 2). No significant bias was found between any of the reconstruction methods and the standard method (p &amp;gt; 0.65). Regression slopes relative to the standard method ranged from 0.993 to 1.080. Changes in reconstruction settings did not alter diagnosis in any patient. Conclusion Changes in reconstruction settings such as filter size, number of iterations, inclusion of time-of-flight or resolution recovery, and regularization, have negligible impact on MBF values based on 15O-water PET analyzed using the automated software. This is likely due to the fact that MBF is determined by the clearance rate of 15O-water rather than its uptake rate such as for other PET tracers, in addition to the used segmentation routines. These results also indicate that quantitative MBF measurements using 15O-water are likely to be robust across different types of PET scanners and hospitals, which is highly important for reliable clinical use of cut-off values for ischemia.

Left ventricular global longitudinal strain in predicting CRT response: one more J-shaped curve in medicine

The aim of the study was: (1) to verify the hypothesis that left ventricular global longitudinal strain (LVGLS) may be of additive prognostic value in prediction CRT response and (2) to obtain such a LVGLS value that in the best optimal way enables to characterize potential CRT responders. Forty-nine HF patients (age 66.5 ± 10 years, LVEF 24.9 ± 6.4%, LBBB 71.4%, 57.1% ischemic aetiology of HF) underwent CRT implantation. Transthoracic echocardiography was performed prior to and 15 ± 7 months after CRT implantation. Speckle-tracking echocardiography was performed to assess longitudinal left ventricular function as LVGLS. The response to CRT was defined as a ≥ 15% reduction in the left ventricular end-systolic volume (∆LVESV). Thirty-six (73.5%) patients responded to CRT. There was no linear correlation between baseline LVGLS and ∆LVESV (r = 0.09; p = 0.56). The patients were divided according to the percentile of baseline LVGLS: above 80th percentile; between 80 and 40th percentile; below 40th percentile. Two peripheral groups (above 80th and below 40th percentile) formed “peripheral LVGLS” and the middle group was called “mid-range LVGLS”. The absolute LVGLS cutoff values were − 6.07% (40th percentile) and − 8.67% (80th percentile). For the group of 20 (40.8%) “mid-range LVGLS” patients mean ΔLVESV was 33.3 ± 16.9% while for “peripheral LVGLS” ΔLVESV was 16.2 ± 18.8% (p < 0.001). Among non-ischemic HF etiology, all “mid-range LVGLS” patients (100%) responded positively to CRT (in “peripheral LVGLS”—55% responders; p = 0.015). Baseline LVGLS may have a potential prognostic value in prediction CRT response with relationship of inverted J-shaped pattern. “Mid-range LVGLS” values should help to select CRT responders, especially in non-ischemic HF etiology patients.

P961 Diagnostic use of proportion between ascending aorta and left atrium in patients referred for coronary artery calcium scoring

Abstract Background Non-contrast-enhanced cardiac computed tomography (NCE-CCT) is currently used for coronary artery calcium (CAC) scoring. Meanwhile, other cardiac, vascular and extra-cardiac structures can be evaluated. Data about ascending aorta (AA) and left atrium (LA) has been quantified separately in a few studies. Their mutual proportion has not been examined, as yet. Aim. We hypothesize that mutual proportion between AA and LA size might help for diagnosing their enlargement before absolute cut-off values are reached. Method Among 7950 patients who had NCE-CCT with a 64 raw scanner (Aquillion, Toshiba) within the last decade in our center, in 797 persons the AA diameter (at the level of pulmonary artery bifurcation) and LA diameter and area (highest value) were measured. Raw AAD values were qualified as abnormal if exceeded upper normal limit UNL) for age and height. Weight, BMI and BSA has not been used in order to avoid falsified results in obese patients. The ratio AAD:LAD was quantified as low (&amp;lt;0.8), normal (0.8-1.2) and high (&amp;gt;1.2). Results There were 45 patients (5.6%) who had AAD higher than age-height predicted UNL, including 24 patients with a raw AAD &amp;gt;43mm (3.0%). The other 752 has their AAD within limits. The means of AAD were 42.9 ± 3.2mm and 33.6 ± 3.6mm (p &amp;lt; 0.001). LA size differed significantly, both in diameters 38.5 ± 7.4 vs 34.2 ± 5.6mm (p &amp;lt; 0.001) and areas 2138 ± 593 vs 1837 ± 481 mm2 (p &amp;lt; 0.001). Data regarding mutual relationship are shown in the fig.1. It is seen that normal mutual proportion (AOLARel =1) in patients with high AAD means that LAD was also increased (left graph, red open square). In 603 patients with normal AAD corresponded with normal LAD. The AAD:LAD &amp;gt;1.2 in 845 subjects might suggest increased AAD in spite to normal raw diameter. Similar rules were found in respect to the LA area. Conclusions Ascending aorta and left atrium enlargement are infrequently recognized in patients referred to CAC scoring. Mutual proportion between AA and LA size might complement diagnostic approach of their abnormalities.

Perspective: The Application of A Priori Diet Quality Scores to Cardiovascular Disease Risk—A Critical Evaluation of Current Scoring Systems

ABSTRACTHealthy dietary habits are the cornerstone of cardiovascular disease (CVD) prevention. Numerous researchers have developed diet quality indices to help evaluate and compare diet quality across and within various populations. The availability of these new indices raises questions regarding the best selection relevant to a given population. In this perspective, we critically evaluate a priori–defined dietary indices commonly applied in epidemiological studies of CVD risk and mortality. A systematic literature search identified 59 observational studies that applied a priori–defined diet quality indices to CVD risk factors and/or CVD incidence and/or CVD mortality. Among 31 different indices, these scores were categorized as follows: 1) those based on country-specific dietary patterns, 2) those adapted from distinct dietary guidelines, and 3) novel scores specific to key diet-related factors associated with CVD risk.The strengths and limitations of these indices are described according to index components, calculation methods, and the application of these indices to different population groups. Also, the importance of identifying methodological challenges faced by researchers when applying an index are considered, such as selection and weighting of food groups within a score, since food groups are not necessarily equivalent in their associations with CVD. The lack of absolute cutoff values, emphasis on increasing healthy food without limiting unhealthy food intake, and absence of validation of scores with biomarkers or other objective diet assessment methods further complicate decisions regarding the best indices to use. Future research should address these limitations, consider cross-cultural and other differences between population groups, and identify translational challenges inherent in attempting to apply a relevant diet quality index for use in CVD prevention at a population level.

Clinical Application of Overlapping Confidence Intervals for Monitoring Changes in Serial Clinical Chemistry Test Results.

BackgroundInterpretation of changes in serial laboratory results is necessary for both clinicians and laboratories; however, setting decision limits is not easy. Although the reference change value (RCV) has been widely used for auto-verification, it has limitations in clinical settings. We introduce the concept of overlapping confidence intervals (CIs) to determine whether the changes are statistically significant in clinical chemistry laboratory test results.MethodsIn total, 1,202,096 paired results for 33 analytes routinely tested in our clinical chemistry laboratory were analyzed. The distributions of delta% absolute values and cut-off values for certain percentiles were calculated. The CIs for each analyte were set based on biological variation, and data were analyzed at various confidence levels. Additionally, we analyzed the data using RCVs and compared their clinical utility.ResultsMost analytes had low indexes of individuality with large inter-individual variability. The 97.5th percentile cut-offs for each analyte were much larger than conventional RCVs. The percentages of results exceeding RCV95% and RCV99% corresponded to those with no overlap at the 83.4% and 93.2% confidence levels, respectively.ConclusionsThe use of overlapping CIs in serial clinical chemistry test results can overcome the limitations of existing RCVs and replace them, especially for analytes with large intra-individual variation.

RELATIVE GRIP STRENGTH CUT-OFF VALUES AND METABOLIC SYNDROME IN THE ELDERLY: THE KOREA NATIONAL HEALTH AND NUTRITION EXAMINATION SURVEY 2014–2017

Background and objectiveThe study aimed to analyze the prevalence of metabolic syndrome (MetS) according to the absolute and relative hand grip strength (HGS) in people aged >60 years. Materials and methodsThe participants included 2721 adults aged between 60 and 79 years (1589 men and 1132 women) who completed measurements of HGS and variables related to MetS. The MetS criteria were based on the third report of the National Cholesterol Education Program; expert panel on detection, eval-uation, and treatment of high blood cholesterol in adults (NCEP-ATP III) guidelines; and waist circumference determined by the Korean Society for the Study of Obesity. HGS was measured three times for each hand and the highest value was retained. After dividing the HGS values into quar-tiles, the highest group was defined as G1 and the lowest as G4. The prevalence of MetS in each group was reported as an odds ratio (OR) calculated using logistic regression analysis. The absolute and relative HGS cut-off values were used for the receiver operating characteristic (ROC) curve. ResultsOf the total participants, 695 men (43.7%) and 646 women (57.1%) were diagnosed with MetS. The absolute cut-off values for HGS were 36.0 kg (AUC 0.533, p=0.015) for men and 19.6 kg (AUC 0.506, p=0.017) for women. The relative cut-off values were calculated as 57.5% (AUC 0.633, p=0.014) for men and 38.9% (AUC 0.617, p=0.017) for women. The participants were divided into quartiles based on the relative HGS. The risk of MetS in the group with the lowest relative HGS (G4) was 5.00 (p<0.001) times greater for men and 2.74 (p<0.001) times greater for women than the highest relative HGS (G1).ConclusionThe relative HGS value was higherin non-MetS subjects compared to the MetS subjects, and asthe relative HGS value was lower, the prevalence of MetS increased to 5.00 times for men and 2.74 times for women.

Clinical Guidelines and PTH Measurement: Does Assay Generation Matter?

PTH is an important regulator of calcium and phosphate homeostasis and bone remodeling. It is metabolized into PTH fragments, which are measured to a different extent by PTH assays of different generations because of differences in fragments recognized and lack of assay standardization. PTH is measured in the workup of several conditions, and clinical guidelines provide recommendations concerning these measurements. This review provides an overview of the impact of differences between PTH assays, applying distinct clinical guidelines for primary and secondary hyperparathyroidism and perioperative use of PTH measurements. Guidelines deal with PTH measurement in different ways, recommending either trend monitoring, the use of a fold increase of the upper reference limit, or an absolute PTH cutoff value. For classic primary hyperparathyroidism (PHPT), the type of PTH assay used will not affect diagnosis or management because the precise concentration of PTH is less relevant. In chronic kidney disease, the guideline recommends treating secondary hyperparathyroidism above a twofold to ninefold PTH increase, which will result in different clinical decisions depending on the assay used. For patients after bariatric surgery, guidelines state absolute cutoff values for PTH, but the impact of different generation assays is unknown because direct comparison of PTH assays has never been performed. During parathyroid surgery, PTH measurements with a third-generation assay reflect treatment success more rapidly than second-generation assays. Increased awareness among clinicians regarding the complexity of PTH measurements is warranted because it can affect clinical decisions.

Optimal Ultrasonographic Measurements for Diagnosing Carpal Tunnel Syndrome in Patients With Diabetic Sensorimotor Polyneuropathy: A Case-Control Study.

ObjectiveTo investigate the optimal sonographic method for diagnosing carpal tunnel syndrome (CTS) in patients with diabetic sensorimotor polyneuropathy (DSP).MethodsA total of 190 participants were divided into four groups based on DSP history and electrodiagnostic results of CTS. The absolute parameters were measured at baseline and the relative values were calculated: maximal cross-sectional area (CSA) of the median nerve throughout the carpal tunnel (Mmax), median nerve CSA at the forearm level (Mf), ulnar nerve CSA at the pisiform level (Upi), difference between Mmax and Mf (∆MM), and difference between Mmax and Upi (∆MU). Then, the optimal ultrasonographic parameters for diagnosing CTS, according to the presence of DSP, using absolute and relative cutoff values were analyzed.ResultsMedian and ulnar nerve CSAs were significantly larger in the DSP group than in the control group. In the DSP participants, the mean Mmax, ∆MM, and ∆MU values were significantly larger in patients with both DSP and CTS than in patients with DSP only. The Mmax thresholds of 9.5 mm2 in the control group and 11.5 mm2 in the DSP group showed the greatest sensitivity and specificity for diagnosing CTS. The ∆MM thresholds of 2.5 mm2 and ∆MU thresholds of 4.5 mm2 had the greatest sensitivity and specificity in both the DSP and control groups.ConclusionMeasurement of Mmax, ∆MM and ∆MU is an optimal ultrasonographic evaluation method for diagnosing CTS in patients with DSP.

Predicting ROSC in out-of-hospital cardiac arrest using expiratory carbon dioxide concentration: Is trend-detection instead of absolute threshold values the key?

AimGuidelines recommend detecting return of spontaneous circulation (ROSC) by a rising concentration of carbon dioxide in the exhalation air. As CO2 is influenced by numerous factors, no absolute cut-off values of CO2 to detect ROSC are agreed on so far. As trends in CO2 might be less affected by influencing factors, we investigated an approach which is based on detecting CO2-trends in real-time. MethodsWe conducted a retrospective case-control study on 169 CO2 time series from out of hospital cardiac arrests resuscitated by Muenster City Ambulance-Service, Germany. A recently developed statistical method for real-time trend-detection (SCARM) was applied to each time series. For each series, the percentage of time points with detected positive and negative trends was determined. ResultsROSC time series had larger percentages of positive trends than No-ROSC time series (p=0.003). The median percentage of positive trends was 15% in the ROSC time series (IQR: 5% to 23%) and 7% in the No-ROSC time series (IQR: 3% to 14%). A receiver operating characteristic (ROC) analysis yielded an optimal threshold of 13% to differentiate between ROSC and No-ROSC cases with a specificity of 58.4% and sensitivity of 73.9%; the area under the curve was 63.5%. ConclusionPatients with ROSC differed from patients without ROSC as to the percentage of detected CO2 trends, indicating the potential of our real-time trend-detection approach. Since the study was designed as a proof of principle and its calculated specificity and sensitivity are low, more research is required to implement CO2-trend-detection into clinical use.

P5248Variability of thoracic aortic diameters according to gender, age and body surface area: nomograms should replace absolute cut-off values?

P5248Variability of thoracic aortic diameters according to gender, age and body surface area: nomograms should replace absolute cut-off values?

Subclinical hypothyroidism: a 'laboratory-induced' condition?

In current literature and guidelines, there is a tendency to define absolute TSH concentrations at which patient follow-up or even pharmaceutical intervention should be initiated. As TSH concentrations depend on the analytical method/platform used for TSH quantification, absolute cut-off values may pose threats for uniform clinical decision-making. In this study we therefore set out to clarify to what extent the method/platform and the reference values applied for TSH influence the clinical interpretation of thyroid parameters. We retrospectively analyzed anonymous TSH results from the Dutch external quality assessment program (EQAS) in relation to reference values advised by different manufacturers. We also examined TSH/free thyroxin (fT4) reference ranges and prevalence of thyroid pathology among different Dutch laboratories, including four cases in which a switch in the measuring platform was made. Our data show that interpretation of thyroid parameters is not only influenced by between-method/platform variation, but is also substantially affected by the variation in TSH/fT4 reference intervals applied in individual laboratories. Additionally, we show that the transition to a novel analytical method/platform can result in a shift in the prevalence of thyroid pathology, especially for subclinical hypothyroidism. Subclinical hypothyroidism can be a 'laboratory-induced' condition. This is an undesirable situation in regard to the clinical implications such a diagnosis can have for patients.

Absolute Versus Relative Myocardial Blood Flow by Dynamic CT Myocardial Perfusion Imaging in Patients With Anatomic Coronary Artery Disease.

The purpose of this study was to evaluate differences in the diagnostic accuracy of absolute and relative territorial myocardial blood flow (MBF) derived from stress dynamic CT myocardial perfusion imaging (MPI) for the detection of significant coronary artery stenosis. Dynamic CT MPI and coronary CT angiography (CTA) datasets from a multicenter registry of 137 patients (mean age, 60.9 ± 8.4 years; 88 men) with suspected or known coronary artery disease were retrospectively analyzed. For each coronary territory, absolute MBF and the MBF relative to remote myocardium (MBF ratio) were calculated. Coronary CTA datasets were visually assessed for significant stenosis (≥ 50% luminal narrowing) in consensus by two observers. Significant stenosis was detected in 137 of 411 (33.3%) vessels. Mean absolute MBF and MBF ratio were statistically significantly lower in territories supplied by arteries with stenosis (80.7 ± 33.7 vs 140.0 ± 38.4 mL/100 mL/min and 0.52 vs 0.89, respectively; both p < 0.0001). ROC analysis showed better discrimination by MBF ratio than by absolute MBF (AUC, 0.925 vs 0.882; p = 0.0022) and increased sensitivity (90.7% vs 82.4%; p < 0.04) and specificity (93.1% vs 80.5%; p < 0.03) for MBF ratio and absolute MBF cutoff values of 0.71 or less and 103 mL/100 mL/min or less, respectively. In stress dynamic CT MPI, relative MBF provides superior diagnostic accuracy compared with absolute territorial MBF values for coronary CTA-detected significant coronary artery stenosis.

Inborn Error of Metabolism (IEM) screening in Singapore by electrospray ionization-tandem mass spectrometry (ESI/MS/MS): An 8 year journey from pilot to current program

IEM screening by ESI/MS/MS was introduced in Singapore in 2006. There were two phases; a pilot study followed by implementation of the current program. The pilot study was over a 4year period. During the pilot study, a total of 61,313 newborns were screened, and 20 cases of IEM were diagnosed (detection rate of 1:3065; positive predictive value (PPV) of 11%). Regular self-review, participation in external quality assessment and the Region 4 Genetic collaborative programs (http://www.region4genetics.org/) had led to the robust development of our current NBS MS/MS program. Overall, from July 2006 to April 2014, we screened a total of 177,267 newborns. The mean age at the time of sampling was 47.9h. Transportation of samples to the testing laboratory averaged 0.92day. Upon receipt of sample, the NBS result was available within 1.64days and within 3.8days if a second tier test was required. Using absolute cut-off values in place of the initial 99th percentile reference range for the analyte markers and the introduction of two 2nd tier tests (MMA and Succinylacetone) had significantly reduced the high recall rate from an initial 1.5% during the period 2006–07 to 0.12% in 2013. The NBS MS/MS program was supported by a centralized confirmatory/diagnostic testing laboratory and a rapid response team of metabolic specialists. The detection rate was 1: 3165 (1:2727 if maternal conditions were also included). There were 23 newborns affected with organic acidemias (incidence: 1:6565), 23 with fatty acid oxidation disorders (incidence: 1:6565), and 10 with amino acidopathies (incidence 1:17,726). The performance metrics for the screening test were acceptable (sensitivity: 95.59%, specificity: 99.85%, PPV: 20%, FPR: 0.15). Participation in the NBS MS/MS program by hospitals was voluntary, and in 2013, the uptake rate was 71% of the annual births. We hope that newborn screening by MS/MS will become a standard of care for all babies in Singapore.

Semi-automated landmark-based 3D analysis reveals new morphometric characteristics in the trochlear dysplastic femur

The authors hypothesise that the trochlear dysplastic distal femur is not only characterised by morphological changes to the trochlea. The purpose of this study is to describe the morphological characteristics of the trochlear dysplastic femur in and outside the trochlear region with a landmark-based 3D analysis. Arthro-CT scans of 20 trochlear dysplastic and 20 normal knees were used to generate 3D models including the cartilage. To rule out size differences, a set of landmarks were defined on the distal femur to isotropically scale the 3D models to a standard size. A predefined series of landmark-based reference planes were applied on the distal femur. With these landmarks and reference planes, a series of previously described characteristics associated with trochlear dysplasia as well as a series of morphometric characteristics were measured. For the previously described characteristics, the analysis replicated highly significant differences between trochlear dysplastic and normal knees. Furthermore, the analysis showed that, when knee size is taken into account, the cut-off values of the trochlear bump and depth would be 1 mm larger in the largest knees compared to the smallest knees. For the morphometric characteristics, the analysis revealed that the trochlear dysplastic femur is also characterised by a 10% smaller intercondylar notch, 6-8% larger posterior condyles (lateral-medial) in the anteroposterior direction and a 6% larger medial condyle in the proximodistal direction compared to a normal femur. This study shows that knee size is important in the application of absolute metric cut-off values and that the posterior femur also shows a significantly different morphology.

Defining Normal Distributions of Coronary Artery Calcium in Women and Men (from the Framingham Heart Study)

Coronary artery calcium (CAC) may improve risk stratification for patients with coronary heart disease (CHD) beyond traditional risk factors. Subjects from the Framingham Heart Study Offspring and Third Generation cohorts (48% women; mean age 53 years) underwent noncontrast electrocardiographically triggered cardiac multidetector computed tomography. The prevalence of absolute CAC (Agatston score [AS] >0, >100, and >400) and relative age- and gender-specific strata (25th, 50th, 75th, 90th, and 95th percentiles) were determined in a healthy subset free of clinically apparent cardiovascular disease or CHD risk factors (n = 1,586), the overall sample at risk (n = 3,238), and subjects at intermediate Framingham risk score (FRS; 6% to 20% 10-year CHD event risk; n = 1,177). Absolute AS and relative cutoffs for CAC increased with age and FRS, were higher in men compared with women in each of the 3 cohorts, and increased from the healthy subset to the overall cohort to subjects at intermediate risk. However, in subjects with CAC, there was substantial disagreement between absolute and relative cut-off values for labeling subjects as having increased CAC. In general, more subjects were considered to have increased CAC using relative cut-off values, especially in women and younger subjects. Fewer subjects at intermediate FRS had increased CAC using comparable absolute versus relative cutoffs (men 32% at AS >100 vs 36% at >75th percentile; women 24% at AS >100 vs 34% at >75th percentile). In conclusion, we provided distributions of CAC in a healthy subset, the overall cohort, and subjects at intermediate risk from the Framingham Heart Study for both absolute and relative cut-off values for CAC. Absolute cutoffs underestimated the proportion of subjects with increased CAC, specifically in women, younger persons, and persons at intermediate CHD risk.

Ability of Peripheral DXA Measurement to Diagnose Osteoporosis As Assessed By Central DXA Measurement

Abstract In order to evaluate the utility of peripheral measurement of bone mineral density (BMD) in the diagnosis of osteoporosis, we measured BMD at the spine and femoral neck with central dual-energy X-ray absorptiometry (DXA), at phalanx with AccuDXA (Schick) as well as proximal and distal forearm with pDXA (Norland) in 835 women ranging in age from 20 to 85 yr. In receiver operating characteristic (ROC) curves, where a positive case was defined as a T-score ≤ –2.5 either on spine or femoral neck, the areas under the curve were not significantly different between sites. At a T-score of –2.5 as determined by each peripheral apparatus, sensitivity and specificity were, respectively, 0.39 and 0.95 for phalanx and 0.75 and 0.85 for proximal forearm whereas they were 0.42 and 0.96 for distal forearm. Using optimal absolute BMD cutoff values improved the results. Sensitivity and specificity were, respectively, 0.79 and 0.83 for phalanx at an absolute BMD value of 0.436 and 0.84 and 0.79 for proximal forearm at a value of 0.703, whereas they were 0.90 and 0.75 for distal forearm at a value of 0.208. Combining the two forearm measurements improves the results slightly. At cutoff values of 0.641 and 0.252, respectively for proximal and distal forearms, sensitivity was 0.83 and specificity was 0.84. Therefore, a peripheral measurement of BMD together with a good clinical evaluation of the osteoporosis risk profile of the patient, can be an interesting tool for the diagnosis of osteoporosis in areas where central DXA is not available.