Single breath diffusing capacity for carbon monoxide: Effects of adjustment for inspired volume dead space, carbon dioxide, hemoglobin and carboxyhemoglobin

In order to assess the additive effects of taking into account dead space volume (V-D), carbon dioxide, hemoglobin (Hb) and carboxyhemoglobin on computation of single breath carbon monoxide diffusing capacity (D(L)COsb), we sequentially applied all the corrections recommended by the 1987 American Thoracic Society (ATS) document on D(L)COsb standardization. We used data from 739 men (333 nonsmokers and 406 current smokers) and 475 women (403 nonsmokers and 72 current smokers) who underwent measurement of D(L)COsb in the decade 1985-1994 at the Lung Function Laboratory of our institute. With respect to the unadjusted D(L)COsb value, significant small differences were found for all the corrected formulas, ranging from -0.18 to 1.48 ml/min/mm Hg in men and from -0.24 to 1.57 ml/min/mm Hg in women. After computing the percent change of D(L)COsb [(unadjusted-adjusted value) x 100/unadjusted value], we observed that the correction for V-D caused an underestimation of D(L)COsb of about 5.8% in men and 7.7% in women. However, when all the corrections were considered, these figures decreased to about 0.9% in males and 2.9% in females. Regarding specifically the correction for Hb, the adjusted value was slightly lower in men, while it was somewhat higher in women, with respect to the unadjusted D(L)COsb. In conclusion, the corrections suggested by ATS in the computation of D(L)COsb, when considered altogether, seem to account for a limited proportion of test variability in usual clinical conditions, especially in males

ECHOCARDIOGRAPHIC QUANTITATIVE TEXTURE ANALYSIS OF TISSUE ACOUSTIC PROPERTIES OF FRESH VERSUS ORGANIZED VENTRICULAR THROMBI

The age of a thrombus can be important clinical information in identifying patients at high risk for embolism, but recognizing the age of thrombi is difficult using only clinical data or a qualitative analysis of two-dimensional echocardiograms. We hypothesize that the quantitative analysis of image texture in two-dimensional echocardiograms would be an accurate method for in vivo differentiation of fresh from old ventricular thrombi. To test this hypothesis, we retrospectively evaluated two-dimensional echocardiographic images of cardiac thrombi detected in patients within the 1st week and at 6 months after an acute myocardial infarction with quantitative texture analysis. Of the quantitative texture measures of the first order, mean gray level, skewness, and kurtosis overlapped between fresh and old thrombi, but uniformity was significantly higher in older thrombi (0.036 +/- 0.008 for fresh vs 0.042 +/- 0.008 for old, P < 0.05). Of the second-order measures, entropy was significantly higher in fresh than in old thrombi (4.36 +/- 0.05 vs 4.58 +/- 0.05, P < 0.05), and angular second moment, correlation, and contrast overlapped. In conclusion, computerized quantitative texture analysis can help to differentiate fresh from old ventricular thrombi: old thrombi are characterized by a decrease in heterogeneity, which can be quantified by this technique

2-DIMENSIONAL ECHOCARDIOGRAPHY IN MYOCARDIAL AMYLOIDOSIS

Two-dimensional echocardiography is the best means of identifying early cardiac amyloid infiltration and gauging its subsequent progression. The early asymptomatic phase is characterized on echocardiography by a mild-to-moderate increase in left ventricular and/or right ventricular wall thicknesses. The distinctive combination of low electrocardiography voltage and increase in left ventricular mass on the echocardiogram, both compatible with substantial amyloid infiltration, is valuable in diagnosis and appears to indicate the severity of the disease. Other ancillary but common findings are left atrial dilatation, a small pericardial effusion, thickening of cardiac valves, papillary muscles, and interatrial septum. Finally, there is a peculiar texture of myocardial walls, with highly refractile areas that are typical, although not specific, of myocardial amyloidosis and can also be quantitatively described by digital image analysis techniques. The echocardiographic appearance of amyloidosis can closely mimic several other diseases. Asymmetric hypertrophy of the septum due to amyloid deposition may occur, simulating hypertrophic cardiomyopathy. The granular sparkling of myocardial walls is also found in myocarditis with severe fibrosis, and it is quite common in hypertrophic cardiomyopathy, as well as in other infiltrative diseases of the myocardium. It is not uncommon that the echocardiographic examination represents a turning point in the work-up of the patient, briskly orienting the clinician towards the correct diagnostic pathway. However, the likelihood of the cardiologist-echocardiographer to successfully and prespectively identify myocardial amyloidosis is substantially higher if all the clinical and electrocardiographic information is reviewed at the time of the echocardiographic examination

QUANTITATIVE TEXTURE ANALYSIS IN ECHOCARDIOGRAPHY - APPLICATION TO THE DIAGNOSIS OF MYOCARDITIS

Altered myocardial texture associated with inflammatory infiltration or fibrosis of the myocardium has already been described using qualitative and subjective analysis of two-dimensional echocardiograms. The aim of this work is to test whether quantitative analysis of regional image texture in two-dimensional echocardiograms would be an accurate method to identify myocarditis and myocardial fibrosis. A set of 20 two-dimensional studies with endomyocardial biopsy evaluation was examined in 13 patients. Biopsy-proven myocarditis was present in 8 studies; myocarditis and fibrosis in 4; fibrosis in 3; healing/healed myocarditis in 5. A control group of 8 normal subjects was also studied by echocardiography. After quantitative texture analysis of the first order, entropy appeared to consistently differentiate myocarditis from controls. Among second-order parameters, patients affected by myocarditis or fibrosis showed a decreased entropy and higher angular second moment versus controls. We conclude that myocarditis and fibrosis induce similar image texture alterations in ultrasonic images, with increased spatial heterogeneity of the gray level distribution, which can be differentiated from normal structures with digital image analysis techniques