Absolute Cross-sectional Area Research Articles

Influence of body mass normalization on the correlations between muscle cross-sectional area and physical performance outcomes in older women.

Normalization is a method used to account for body mass in clinical practice and research. It is unclear if thismethod will improve the correlation between muscle cross-sectional area (CSA) and physical performance. We examinedthe correlations between quadriceps muscle morphology parameters and physical performance outcomes in older women.Material and methods: Twenty older women participated in this study. Ultrasound imaging was used to measure quadricepsmuscle CSA and echo intensity. Muscle CSA was expressed as an absolute value (cm2) and as a relative value normalized tobody mass (cm2/kg). Physical performance was assessed from timed up-and-go and 6-min walk tests. Relative CSAwas significantly related to timed up-and-go scores (r=-0.489, p=0.029) and 6-min walking speed (r=0.606, p=0.005), whereasabsolute CSA was not significantly associated with these performances (r=-0.231, p=0.327 and r=0.373, p=0.105). There wasa significant correlation between absolute CSA and body mass (r=0.456, p=0.043). There were also significant correlationsbetween echo intensity and timed up-and-go scores (r=0.556, p=0.011) and 6-min walking speed (r=-0.484, p=0.031). Our study showed that relative CSA correlated better than absolute CSA with physical performance. These findingssupport the need to normalize measurements of muscle CSA to body mass in older adults.

Interfacial thermal stresses of segmented thermoelectric generators

The segmented structure can effectively improve the performance of a thermoelectric generator (TEG), but the interfacial thermal stress between adjacent segments seriously threatens the reliability of segmented TEGs. Noticing this, we investigate the mechanical performance of a segmented TEG via theoretical and numerical methods. Results show that the structural stress depends on the ratio of cross-sectional areas between p- and n-type TE legs rather than the absolute cross-sectional areas, while the height ratio of different segments has a significant influence on structural stress. Different from structural stress, the thermal stress induced by unmatched thermal expansion between different segments increases rapidly with the increase of cross-sectional area, and can easily exceed 20% of the total interfacial stress. Besides, both the conversion efficiency and interfacial stress can be optimized by adjusting the ratio of cross-sectional areas. Our results provide the theoretical basis and guidance in the design of segmented TEGs.

Computational fluid dynamics model of laryngotracheal stenosis and correlation to pulmonary function measures

3D models of airway lumens were created from CT scans of 19 patients with laryngotracheal stenosis. Computational fluid dynamics (CFD) simulations were completed for each, and results were compared to measured peak inspiratory flow rate, grade of lumen constriction, and measures of airway geometry. Results demonstrate flow resistance and shear stress correlate with degree of lumen constriction and absolute cross-sectional area as well as flow rate. Flow recirculation depends on airway constriction but does not vary with flow rate. Resistance and wall shear stress did not correlate well with functional measures. Flow recirculation did differ between subjects with higher functional measures and subjects with lower functional measures. This analysis provides mathematical models to predict airway resistance, wall shear stress, and flow reversal according lumen constriction and inspiratory flow rate. It suggests aerodynamic factors such as flow recirculation play a role in differences in functional performance between patients with similar airway measures.

Quantitative anatomical analysis of the carpal tunnel in women and men

PurposeThe main objective of this study was to identify anatomical differences between men and women in the absolute and relative size of the carpal tunnel (CT), its inner structures, and related external anatomical structures in order to shed light on the higher prevalence of CT syndrome (CTS) in women. Basic proceduresWe have dissected the forearms and hands of ten men and ten women and compared the cross-sectional area (CSA) of the CT between the two sexes. The size of the CT relative to the tendons passing through it, the median nerve (MN), and to hand and wrist size was also compared between men and women. Main findingsThe absolute CSAs of the CT and other parameters were larger in men than in women. The CSA of the CT relative to the length of the capitate bone was also larger in men. However, no significant differences were observed between men and women in the size of the CT relative to its inner structures. Principal conclusionsThe size of the inner structures of the CT are in proportion to that of the CT itself in both sexes. These findings suggest that the etiology of CTS seems to be primarily related to workload and personal traits.

Achilles Tendon Length Is Not Related to 100-m Sprint Time in Sprinters.

This study examined the relationship between Achilles tendon (AT) length and 100-m sprint time in sprinters. The AT lengths at 3 different portions of the triceps surae muscle in 48 well-trained sprinters were measured using magnetic resonance imaging. The 3 AT lengths were calculated as the distance from the calcaneal tuberosity to the muscle-tendon junction of the soleus, gastrocnemius medialis, and gastrocnemius lateralis, respectively. The absolute 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = -.023 to .064, all Ps > .05). Furthermore, to minimize the differences in the leg length among participants, the 3 AT lengths were normalized to the shank length, and the relative 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = .023 to .102, all Ps > .05). Additionally, no significant correlations were observed between the absolute and relative (normalized to body mass) cross-sectional areas of the AT and personal best 100-m sprint time (r = .012 and .084, respectively, both Ps > .05). These findings suggest that the AT morphological variables, including the length, may not be related to superior 100-m sprint time in sprinters.

Neuromuscular ultrasound in ulnar neuropathy at the elbow: correlation with electrodiagnostic studies

IntroductionUlnar nerve entrapment is the second most common entrapment neuropathy in the upper limb after carpal tunnel syndrome, and, if left untreated, it may lead to significant functional impairment and disability.ObjectiveThe aim of this study was to perform clinical, electrodiagnostic (EDX), and neuromuscular ultrasound assessment for patients with ulnar neuropathy at the elbow, to determine the possible roles of neuromuscular ultrasound in the localization of the neuropathy, in the detection of its possible etiologies and in the determination of its severity.Patients and methodsA sample of 15 (22 elbows) patients was recruited and subjected to full medical history, neurological assessment, EDX studies, and neuromuscular ultrasound examination. Ten (20 elbows) age-matched and sex-matched healthy volunteers were also recruited and served as a control group.ResultsThis study revealed significantly enlarged ulnar nerve cross-sectional area (CSA) at the ulnar groove and below the elbow and supracondylar sites in patients compared with the control group. receiver-operating characteristic curve analysis revealed high diagnostic accuracy of the absolute CSA at the ulnar groove, and below the elbow and supracondylar sites, with an area under the curve of 0.8, 0.8, and 0.9, respectively, and the cutoff values were >9, >8, and >8, respectively. The area under the curve for the ‘maximum CSA/midforearm CSA ratio’ was 0.9, with a cutoff value of more than 1.3.ConclusionOur study data suggest that neuromuscular ultrasound (NMUS) examination may play a potentially important role in the assessment of ulnar neuropathy at the elbow. It can localize the lesion and disease severity, and it can differentiate between patients and controls, given its high diagnostic ability. Abnormalities in ultrasonographic features of ulnar nerve entrapment with regard to CSA and ratio between ‘maximum CSA and midforearm CSA’ at the elbow was correlated with EDX findings.

Jugular Anomalies in Multiple Sclerosis Are Associated with Increased Collateral Venous Flow.

To date, research on extracranial venous collaterals has been focused on structure, with relatively little attention paid to hemodynamics. We addressed this limitation by quantitatively comparing collateral flow in patients with multiple sclerosis and healthy controls by using phase-contrast MR imaging. We hypothesize that patients with MS with structurally anomalous internal jugular veins will have elevated collateral venous flow compared with healthy controls. The sample consisted of 276 patients with MS and 106 healthy controls. We used MRV to classify internal jugular veins as stenotic and nonstenotic based on an absolute cross-sectional area threshold in 276 patients with MS and 60 healthy controls; 46 healthy controls lacked this imaging. Individual and total vessel flows were quantified by using phase-contrast MR imaging on all patients. Veins were classified by extracranial drainage type: internal jugular veins (I), paraspinal (II), and superficial (III). Differences among healthy controls, patients with MS, nonstenotic patients, and stenotic subgroups in total venous flow by vessel type were evaluated in a general linear model for statistical analysis. In the MS group, 153 patients (55%) evidenced stenosis, whereas 12 (20%) healthy controls were classified as stenotic (P < .001). Compared with healthy controls, the MS group showed lower type I flow and increased type II flow. Stenosis was associated with reduced flow in the type I vessels [F(1272) = 68; P < .001]. The stenotic MS group had increased flow in the type II vessels compared with the nonstenotic MS group [F(1272) = 67; P < .001]. Compared with healthy controls, patients with MS exhibit reduced venous flow in the main extracerebral drainage vein (internal jugular vein). In contrast, flow in the paraspinal venous collaterals is elevated in patients with MS and exacerbated by venous stenosis. Collateral drainage may be a compensatory response to internal jugular vein flow reduction.

Influence of body adiposity on structural characteristics of skeletal muscle in men and women

The structure of skeletal muscle (SM) can be characterized by quantitative (size) and qualitative (composition) attributes, which are disparately reported to be influenced by body adiposity. This study tests the hypothesis that body adiposity exerts a systematic influence on these muscle characteristics and evaluates the possible functional implications for movements. Lower limb SM volume (VSM) and attenuation (ATTSM), an inverse measure of lipid infiltration in muscle, were determined with computed tomography in 21 men (BMI=21-36kgm(-2) ; age=31-71years.) and 18 women (BMI=19-35kgm(-2) ; age=32-76years.). After adjusting for age, a multivariate regression analysis revealed that body adiposity positively correlated (P<0·05-0·001) with absolute VSM and cross-sectional area (CSA) in both genders, while VSM per unit body mass (VSM/BM) decreased with adiposity (P<0·001) in women and was constant in men. ATTSM was higher in men (P<0·05) and decreased (P<0·05) with adiposity in both genders. The product of ATTSM by average muscle CSA (predictor of maximal strength) and by VSM/BM (predictor of maximal dynamic performance) was lower in women (P<0·001) and was reduced by age in both genders (P<0·05-0·01), while obesity had a negative effect (P<0·001) only on the predictor of performance. In conclusion, body adiposity significantly increases SM size and reduces ATTSM. Structural indicators accounting for both quantitative and qualitative characteristics of SM may be useful predictors of the effects of obesity on motor function at different ages. With rising body adiposity and advancing age, women appear mostly affected by the decline of SM features relevant for motor performance.

Size Variation Between Contralateral Infraclavicular Axillary Veins Within Individual Patients—Implications for Subclavian Venous Central Line Insertion*

Vein size and use of dynamic ultrasound guidance have been shown to be directly related to a reduction in insertion failure and complication rates during subclavian vein catheterization. We hypothesized that contralateral infraclavicular axillary vein sizes are significantly different within the same patient. We also aimed to demonstrate the relationship of subject's anthropomorphic indices with vein size and contralateral vein size difference. Prospective observational study. Operating theatre of a tertiary hospital. Fifty adult elective and emergency surgical patients. The largest dimensions of each patient's left and right infraclavicular axillary veins were measured with two-dimensional cross-sectional ultrasound examinations. The absolute difference between sides in individual patients was calculated using a paired difference t test and the relationship between hand dominance and vein size calculated by a paired difference t test of dominant side vein size minus nondominant side vein size Forty-five patients (90%) of patients were right hand dominant. The mean proportional cross-sectional area difference between left and right sides in individual patients was 59.7% (SEM 9.2%), with absolute cross-sectional area difference of 26.7 mm (SEM 2.8 mm). All test statistics reached statistical significance at p < 0.0001. There was no relationship between right hand dominance and ipsilateral infraclavicular axillary vein size (p = 1.0), nor was there any clinically significant correlation between subject's anthropomorphic indices and ipsilateral infraclavicular axillary vein size or contralateral vein size difference (largest Pearson's r = 0.22). Contralateral infraclavicular axillary vein sizes within the same patient are significantly different in the adult surgical population and bear no clear relation to patient hand dominance. The magnitude of contralateral difference or absolute ipsilateral infraclavicular axillary vein size cannot be predicted by a subject's anthropomorphic indices. All patients in whom subclavian central line insertion is planned should have both sides examined by ultrasound to determine which side has the largest vessel.

Morphometry of corpus callosum in Williams syndrome: shape as an index of neural development

Brain abnormalities in Williams syndrome (WS) have been consistently reported, despite few studies have devoted attention to connectivity between different brain regions in WS. In this study, we evaluated corpus callosum (CC) morphometry: bending angle, length, thickness and curvature of CC using a new shape analysis method in a group of 17 individuals with WS matched with a typically developing group. We used this multimethod approach because we hypothesized that neurodevelopmental abnormalities might result in both volume changes and structure deformation. Overall, we found reduced absolute CC cross-sectional area and volume in WS (mean CC and subsections). In parallel, we observed group differences regarding CC shape and thickness. Specifically, CC of WS is morphologically different, characterized by a larger bending angle and being more curved in the posterior part. Moreover, although CC in WS is shorter, a larger relative thickness of CC was found in all callosal sections. Finally, groups differed regarding the association between CC measures, age, white matter volume and cognitive performance. In conclusions, abnormal patterns of CC morphology and shape may be implicated in WS cognitive and behavioural phenotype.

Noninvasive test of nitrate-induced coronary vasomotion by 1.5-T whole-heart 3D magnetic resonance angiography using a T2-prepared SSFP sequence

This study was aimed to investigate the use of 1.5-T whole-heart 3D coronary MRA employing a T2-prepared SSFP sequence for assessing epicardial coronary artery vasodilation following exogenous nitrates. Navigator-gated whole-heart 3D coronary MRA was performed before and after sublingual nitroglycerin (NTG) in 22 volunteers and a T2-prepared SSFP sequence was used for imaging of coronary arteries without MR contrast agent. Coronary cross-sectional area was measured on pre- and post-NTG images of equivalent coronary segments in the major coronary arteries and whole-heart coronary vasodilation was analyzed quantitatively. Measurements were obtained by two independent investigators. Coronary vasodilation could be observed directly on multiplanar reformatted and three-dimensional volume-rendered MR images. On quantitative analysis, NTG administration results in the whole-heart coronary vasodilation by an average of 37.3 ± 12.7%. There was moderate yet significant correlation between the NTG-induced vasodilation and age (r = -0.52, P = 0.02). The mean absolute cross-sectional area of the coronary arteries was significantly higher after sublingual NTG in all the major coronary arteries. The coronary area measurements had an interobserver variability of 8 ± 3% and an intraobserver variability of 4 ± 2%. Non-contrast-enhanced 1.5-T SSFP whole-heart coronary MRA can noninvasively measure endothelium-independent coronary vasodilation over the entire heart with high feasibility and is a promising noninvasive method to explore whole-heart coronary smooth muscle cell function following exogenous nitrates in clinical practice.

Epidemiological Analysis of Chronic Rhinitis in Pediatric Patients

Nonallergic rhinitis is a poorly understood entity, especially among pediatric patients. The objective of this study was to identify clinical features that may distinguish phenotypes of allergic and nonallergic patients and to evaluate the usefulness of current diagnostic modalities. We reviewed medical records for 151 pediatric patients with perennial rhinitis, evaluated in a multidisciplinary allergy and otolaryngology clinic. Results obtained by standard history, validated sinus and Nasal Quality of Life Survey (SN-5), epicutaneous allergy testing, acoustic rhinometry, and sinus CT were compared. Nasal congestion was the most frequent primary presenting complaint (62%). Among subjects having a positive allergy test, associated eye symptoms were more frequent (p = 0.01) and responses to the SN-5 allergic domain were higher (p = 0.02). Sinus CT scores were similar among allergic and nonallergic subjects (median 7 and 8, respectively) and did not correlate with symptom scores (p = 0.6). Among nonallergic subjects, quality of life ratings weakly correlated with sinus CT scores (r = 0.4; p = 0.05). By rhinometry, absolute mean cross-sectional area was similar among allergic (0.32 cm(2)) and nonallergic (0.36 cm(2)) subjects and did not correlate with symptom scores (p = 0.8 for allergic and p = 0.6 for nonallergic subjects). Distinct groups of nonallergic patients including those with prominent conjunctival pruritus (n = 24), frequent cold symptoms (n = 3), and chronic sinus disease (n = 2) were observed. It is difficult to distinguish allergic and nonallergic rhinitis in patients with perennial disease, but associated eye symptoms and questionnaire responses are predictive of allergy. Acoustic rhinometry and sinus CT suggest that physical obstruction and sinus disease are not related to nasal symptoms including, surprisingly, the sensation of congestion.

高校生スポーツ選手の大殿筋断面積の競技種目特性

This study investigated the cross-sectional area of the gluteus maximus muscle in high school athletes with reference to sex- and sport-related differences. The subjects were 269 male and female athletes (age 17.2±0.7 yr) majoring in 12 events: sprinting, long-distance, throwing events, volleyball, badminton, boating, canoeing, sailing, soccer, basketball, wrestling and judo. Thirty-six untrained high-school students also participated as controls. The muscle cross-sectional area (CSA) was determined from an axial magnetic resonance image using a slice level through the greater trochanter. Fat-free mass (FFM) was also measured by air-plethysmography, and the relationship between CSA and FFM was analyzed. The CSA and FFM showed a high correlation (r=0.80 for males and 0.71 for females) and there was no gender difference in the regression equation (CSA=3.92*FFM0.83 for the pooled data). The absolute CSA was larger in males than in females. The largest CSA was found in judo and throwing-event athletes of both genders, and the smallest in canoeing and long-distance athletes, whose CSA was comparable to that of the controls. However, when the CSA was divided according to FFM0.83 in order to control for body-size difference in sex and sports events, there was no significant difference in the value between genders. Moreover, although the body-size controlled value was the largest in badminton and sprint athletes of both genders, no significant event-related differences were found for males, and only canoeists showed a value that was less than that for badminton and sprint athletes among females. In conclusion, the development of the gluteus maximus appears to show a sport-specific difference among high school athletes; however, compared with thigh muscle groups suggested in previous studies, no sports-specific tendency was apparent when FFM was controlled for.

Panoramic ultrasonography is a valid method to measure changes in skeletal muscle cross-sectional area

The purpose of this study was to examine the reliability and validity of the "panoramic" brightness mode ultrasonography (US) method to detect training-induced changes in muscle cross-sectional area (CSA) by comparison with results obtained using magnetic resonance imaging (MRI). Out of 27 young male volunteers, 20 subjects were assigned to training group and seven to non-training control group. Muscle CSAs of vastus lateralis were analyzed by MRI and US before and after 21 weeks of either heavy resistance training or control period. Measured by both the US and MRI, the resistance training induced significant increases (~13-14%, P < 0.001) in muscle CSA, whereas no changes were observed in control group. A high repeatability was found between the two consequent US measurements (intraclass correlation coefficient, ICC of 0.997) with standard error of measurement (SEM) of 0.38 cm(2) and smallest detectable difference of 1.1 cm(2). Validity of the US method against MRI in assessing CSA of VL produced ICC of 0.905 and SEM of 0.87 cm(2) with high limits of agreement analyzed by Bland and Altman method. However, the MRI produced systematically (10 +/- 4%, P < 0.01) larger CSA values than the US method. The US showed high agreement against MRI in detecting changes in muscle CSA (ICC of 0.929, SEM of 0.94 cm(2)). The results of this study showed that the panoramic US method provides repeatable measures of a muscle CSA although MRI produced larger absolute CSA values. Moreover, this US method detects training-induced changes in muscle CSA with a comparable degree of precision to MRI.

Relation Between Individual Plaque Components and Overall Plaque Burden in the Prospective, Multicenter Virtual Histology Intravascular Ultrasound Registry

The impact of total plaque burden on absolute and relative amounts of each virtual histologic (VH) intravascular ultrasound (IVUS) plaque component has yet to be studied. We analyzed gray-scale and VH-IVUS findings in the first 990 patients enrolled in the 3,000+ patient global VH-IVUS registry. Whole pullback plaque burden and absolute and relative cross-sectional areas of fibrous tissue, fibrofatty plaque, dense calcium, and necrotic core were analyzed using a linear regression statistical model. Overall, absolute cross-sectional areas of each of the 4 plaque components correlated with total plaque cross-sectional area; however, the correlation between fibrous tissue and total plaque cross-sectional area was stronger than the correlation between fibrofatty plaque, dense calcium, or necrotic core and total plaque cross-sectional area. This was also true overall for each of the subgroups analyzed (gender, age, and presence/absence of acute coronary syndromes). Slope of the regression line relating each plaque component to overall plaque mass showed that 50% of the plaque cross-sectional area increase was because of fibrous tissue with a more gradual increase in fibrofatty plaque, dense calcium, and necrotic core. However, when comparing relative amounts of each plaque component with total plaque cross-sectional area, there was no significant relation between the increase in fibrous tissue, fibrofatty plaque, dense calcium, and necrotic core and the increase in total plaque cross-sectional area. In conclusion, only the absolute area of each plaque component correlated to overall plaque area, not the relative amount of each plaque; therefore, VH-IVUS plaque component increases must be analyzed by controlling for increases in plaque mass.

A Means to Accommodate Residual Limb Movement During Optical Scanning: A Technical Note

A technique is described for correcting for subject movement while imaging the residual limb of a person with a transtibial amputation. Small reflective markers were placed on the residual limb, and then their motions tracked during scanning using two stationary cameras. The marker position measurements were used to generate appropriate translational and rotational transformation matrices so that limb motion could be corrected for during the 1.5-s scan interval. Evaluation tests showed good performance for moderate (2-4 mm) to high (5-8 mm) motion cases. The difference in mean absolute cross-sectional area between the test scan and a stationary reference scan was reduced by approximately one half when motion correction was used compared with when motion correction was not used. The algorithm broke down for exaggerated motion ( >or= 9 mm) cases, particularly in areas outside the region encompassed by the markers. The developed method is useful in prosthetics research where high resolution shape measurement is needed, for example in cases where residual limb shape or volume change is of interest.

Development of brain vessels in human embryos and fetuses in conditions of prenatal exposure to alcohol

Light and electron microscopy were used to study the characteristics of the formation of brain vascular structures at the early stages of development in conditions of maternal alcoholization during pregnancy. Computer morphometric methods using the Scion Image system for image analysis showed that fetuses at 11-12 weeks of development in conditions of prenatal alcohol exposure showed a decrease in the mean absolute cross-sectional area of vessels in the intermediate layer of the brain, with an increase in their relative area and an increase per unit area of sections, as compared with the control group. Vessels started to differentiate into arteries and veins from 10 weeks of development.

Exendin-4, but not dipeptidyl peptidase IV inhibition, increases small intestinal mass in GK rats

Long-term treatment with dipeptidyl peptidase IV inhibitors (DPPIV-I) or glucagon-like peptide (GLP)-1 analogs may potentially affect intestinal growth by down- or upregulating the intestinotrophic hormone GLP-2. This study compared the intestinotrophic effects of 12-wk administration of vehicle, exendin-4 (Ex-4; 5 nmol/kg bid sc), or DPPIV-I (NN-7201, 10 mg/kg qd orally) in GK rats. Some animals were observed additionally for 9 wk after the end of treatment. Both treatments lowered glycated hemoglobin A1c at wk 12 vs. control (Ex-4, -0.8%; DPPIV-I, -0.4%). Body weight was reduced by Ex-4 compared with control (361 +/- 4 vs. 399 +/- 5 g; P < 0.001) because of reduced food intake, whereas neither parameter was affected by DPPIV-I. Linear bone growth was unaffected by either treatment. After treatment end, food intake in Ex-4 animals increased, and, by wk 21, body weight was identical in all groups. The small intestine of Ex-4-treated animals was larger at wk 12 compared with control (length, 135.6 +/- 1.6 vs. 124.5 +/- 2.3 cm, P < 0.001; absolute weight, 8.4 +/- 0.2 vs. 6.4 +/- 0.4 g, P < 0.001), being most pronounced proximally, where the absolute cross-sectional area related to body weight increased by 24% because of increased mucosal thickness. These effects were reversible, and 9 wk after the end of treatment, no differences between Ex-4 and control were apparent. Plasma GLP-2 concentrations were unaltered by either treatment, and Ex-4 had no agonistic or antagonistic effects on the transfected GLP-2 receptor. DPPIV-I had no intestinal effects. In conclusion, the continued presence of Ex-4 is necessary to maintain weight loss in GK rats. Effective antihyperglycemic treatment with Ex-4 increases intestinal mass reversibly, whereas DPPIV-I lacks intestinal effects.

Clinical predictors in obstructive sleep apnea patients with computer-assisted quantitative videoendoscopic upper airway analysis.

To identify the clinical predictors and assist surgeons in their clinical management of obstructive sleep apnea (OSA). A prospective study with a new approach to analyze the static and dynamic upper airway morphology between patients with OSA and normal subjects. Quantitative computer-assisted videoendoscopy (validated with upper airway magnetic resonance imaging) was performed in 49 (43 males, 6 females) patients with OSA and compared with 39 (22 males, 17 females) controls (apnea-hypopnea index [AHI] < 5). Absolute cross-sectional areas and transverse and longitudinal diameters at the retropalatal and retrolingual levels were measured during end of quiet respiration and during Mueller's maneuver in the erect and supine positions, allowing us to study static and dynamic morphology (collapsibility) of the upper airway. Three thousand seven hundred forty-four (3,744) parameters were analyzed. In males, retropalatal and retrolingual areas during Mueller's maneuver in the supine position of 0.7981 cm (relative operating characteristics [ROC] = 0.9284, positive pressure ventilation [PPV] = 86.05%, negative pressure ventilation [NPV] = 84.62%) and 2.0648 cm (ROC = 0.8183, PPV = 76%, NPV = 83.33%), respectively, were found to be good predictors/cut-off values for OSA. The retropalatal area measured in the supine position (AS1 mol/L) and collapsibility of the retropalatal area in the supine position (CAS1) were found to have significant correlations with severity of OSA. In females, the areas measured during Mueller's maneuver in the supine position of 0.522 cm at the retropalatal level (ROC = 1, 100% PPV and NPV) and the transverse diameter at the retrolingual level during erect Mueller's maneuver of 1.1843 cm (ROC = 0.9056, PPV = 100%, NPV = 83.33%) were found to be predictive. All measurements at the retropalatal level and in the supine position had higher predictability. Area measurements obtained during Muller's maneuver were more predictive (ROC > 0.9910) than resting measurements (ROC >0.8371). Several sex and anatomic-site specific formulas with excellent predictability (ROC close or equal to 1) were also devised. Upper airway Mueller's studies are predictive and useful (independent samples t test/Mann-Whitney U test, ROC) in identifying patients with OSA. With these sex and anatomic-site specific OSA predictors/formulas and this innovative clinical method, we hope to assist other surgeons with quantitative clinical diagnosis, assessment, surgical planning, and outcome assessment tools for OSA patients.

Effect of passive myocardium on the compliance of porcine coronary arteries.

The objective of this study was to determine the effect of passive myocardium on the coronary arteries under distension and compression. To simulate distension and compression, we placed a diastolic-arrested heart in a Lucite box, where both the intravascular pressure and external (box) pressure were varied independently and expressed as a pressure difference (DeltaP = intravascular pressure - box pressure). The DeltaP-cross-sectional area relationship of the first several generations of porcine coronary arteries and the DeltaP-volume relationship of the coronary arterial tree (vessels >0.5 mm in diameter) were determined using a video densitometric technique in the range of +150 to -150 mmHg. The vasodilated left anterior descending (LAD) coronary artery of six KCl-arrested hearts were perfused with iodine and 3% Cab-O-Sil. The intravascular pressure was varied in a triangular pattern, whereas the absolute cross-sectional area of each vessel and the total arterial volume were calculated using video densitometry under different box pressures (0, 50, 100, and 150 mmHg). In the range of positive DeltaP, we found that the compliance of the proximal LAD artery in situ (4.85 +/- 3.8 x 10-3 mm2/mmHg) is smaller than that of the same artery in vitro (16.5 +/- 6 x 10-3 mm2/mmHg; P = 0.009). Hence, the myocardium restricts the compliance of the epicardial artery under distension. In the negative DeltaP range, the LAD artery does not collapse, whereas the same vessel readily collapses when tested in vitro. Hence, we conclude that myocardial tethering prevents collapse of large blood vessel under compression.