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Clinical use of 3D echocardiography for serial assessment of left ventricular mass regression in hypertensive patients
Journal of the American Society o f Echocardiography Volume 8 Number 3
10D
AUTOMATED LEFT VENTRICULAR ENDOCARDIAL SURFACE DELINEATION USING 3D ECHOCARDIOGRAPHIC IMAGES AND KOHONEN NEURAL NETWORK. M Belohlavek MD, J Buithieu IVID,A Manduca Phi), DA Foley MD, T Behrenbeck MD PhD, JF GreenieafPhD, JB Seward MD. Mayo Clinic, Rochester, MN
Abstracts 387
12D
INCREASED LEFT VENTRICULAR M A S S BY 3D ECHO IN N O R M O T E N S I V E PATIENTS W I T H H Y P E R T E N S I V E RESPONSE T O E X E R C I S E Olakunie O. Akinboboye MD, Ruth Fernandez, Aasha S. OopaI MD, Zhanqing Shen MD, Donald C. Delisi, Matthew J. Schnellbaecher MD, David K. Blood MD, Donald L. King MD. Columbia University, New York, NY. Increased LV mass is the most significant predictor of cardiac morbidity and mortality except for age. One third of patients with hypertensive response to exercise (ExHBP) will progress to clinical hypertension within five years, however, the relationship of exercise induced hypertension to increased LV mass is unknown, The purpose of this study was to test the hypothesis that patients normotensive at rest but with hypertensive response to exercise have increased LV mass. 15 consecutive normotensive parle nts with atypical chest pain, negative treadmill stress test, and hypertensive response to exercise (systolic blood pressure increase with exercise >85 mm Hg in males and >60 mm Hg in females) were evaluated by 3D echo using a previously validated method for LV mass determination. Patients with documented coronary artery disease, valvular heart disease, diabetes, and abnormal resting ECG were excluded. 3D echo data sets of 8-10 non-parallel, unevenly spaced, non-intersecting short axis images were acquired using an acoustic spatial locater, line of intersection display and personal computer. Endocardial and epicardial boundaries were manually traced and volumes computed using a polyhedral surface reconstruction algorithm. Myocardial mass = myocardial volume x 1.05 g/ml, Mass was indexed to height2 (g/m2). Age and sex matched controls were drawn from a data base o f normal subjects whose LV mass had previously been determined by 3D echo. Data were analyzed to obtain range, mean, and standard deviation and the groups were compared using the unpaired T test. Results: m._..~n range mean mass index(g/m2) mass index(g/m2) _n mass (g) Control 10 111 g 28-52 g/m2 42 g/m2 ExHBP 15 157 g 38-68g/m2 54g/m2 The unpaired T test showed the two groups to be significantly different (T=-4.2, p<0.0004) Conclusion: Left ventricular mass index in nonnotensive patients with exercise induced hypertension is significantly increased in comparison to normal controls,
13D
WHAT IS A CLINICALLY S I G N I F I C A N T CHANGE OF LV EJECTION FRACTION BY 3D ECHO ? A DETERMINATION OF TEST-RETEST VARIABILITY Olakunle O. Akinboboye MD, Zhanqing Shen MD, Aasha S. Gopal MD, Matthew J. Schnellbaecher MD, Donald L. King MD. Columbia University, New York, New York. Reliable, serial, non-invasive measurement of left ventricular (LV) ejection fraction (EF) is essential for selecting and timing therapeutic nterventions. Three-dimensional echocardiography (3D ECHO) EF has previously been demonstrated to be comparable (F test, p=NS) to the radionuchde (MUGA) EF in the clinically relevant range of 3065%. The purpose of this study is to establish the test-retest variability of 3D ECHO for determination of LV EF, 22patients having clinically indicated MUGA underwent single data set 3D ECHO within 2 hours by two independent observers, one experienced (2 years) and one inexperienced (10 exam training set). Patients with MUGA EF _>70% were excluded because MUGA is imprecise above this level. Each observer performed two complete examinations in sequence. Between exams the patient sat up and was then re-positioned on the examination table. 8-10 short axis cross-sections of the LV were obtained using an acoustic spatial locater, line of intersection display and personal computer. The images were manually traced by the observer acquiring the exam. Volumes were computed by ventricular reconstruction and the EF calculated. Each observer was blinded to the other's results. 3D ECHO EF data were compared to MUGA EF by linear regression and limits of agreement analysis, Test-retest intraobserver and interobserver variability were calculated, Results: n = 22, EF range = 10-69%. Test - Retest Interobs Limits Intraobs r SEE Bias ~ Variab Vanab lnexp 0~97 4,4% -0.9% 9.1% ll.3%ofEF (combined) Exper 0,98 3.3% -0.6% 6.7% 4.7%ofEF 11.9% CONCLUSIONS: 3D ECHO EF is comparable to MUGA in the range i0-69% with high correlation, low variance, and no bias. 95% of the time 3D ECHO by an experienced observer will provide an EF within 6.7% of MUGA. With a single experienced observer test-retest intraobserver variability is very low. Thus, an EF change between two 3D ECHO examinations of greater than 9.4% (2 x 4.7%) obtained by the same experienced observer will be significant 95% of the time. 3D ECHO EF may be substituted for MUGA EF determination.
We have developed an initial working model of user-independent endocardial surface extraction which combines: [1] an algorithm for determining the probability of occurrence &the endocar~lium at certain image locations, and_J2] a higher level of processing represented by a Kohonen network. It effectively applies a priori shaoe an~t smootl~ness constraints to the data to generate the boundary surface approxamatton. Methods: We have combined previously developed algorithms for noise and speckle reduction with establishedtechniques for image gradient calculation. The endocardial ~radients were adiusted fdr angglar disparity with the vector direc%d from a user-ffesignated origin inside the left ventricular (LV) cavity. Each adjusted local ~radient provided the weighted probability nloccurrence of the LVendocardium at a particular image element location. This information was then present&l to a Kohonen neural net for LV endocardial delineation. Results: The Kohonen net automatically expands itself inside the LV cavity, generating a continuous smooth outline along areas with high probability of occurrence of the endocardium (figure). In areas of image dropout, the neural network makes logical assumptions of the endocardium location without escaping beyond endocaritial boundaries. Conclusions: Using a neural network, the LV cavity boundary can be delineated even in areas of image dropout. This 3D technique represents an important step in developing an accurate automated representation otthe LV cavity boundary for shape analysis and volume quantitation without geometric assumptmns. A 3D approach to a neural network is a unique advance in quantitative echocardiography.
Ao: aortaLV, RV: left,rightventricle
11D
Kohonennet: IS, TS: initial,tenninalstatus
C L I N I C A L USE OF 3D E C H O C A R D I O G R A P H Y FOR SERIAL ASSESSMENT OF LEFT VENTRICULAR MASS REGRESSION IN HYPERTENSIVE PATIENTS Aasha S. Gopal MD, Matthew J. Schnellbaecher MD, Zhanqing Shen MD, Andrew M. Keller MD, Olakunle O. Akinboboye MD, Peter M, Sapin MD, Donald L. King MD. Columbia University, NY, NY. Increased LV mass is an important, independent predictor of cardiac mortality. Measurement of its regression can be useful gauging the efficacy of therapy. LV mass computation by 3D echo has been validated and shown to be superior to 2D echo in normal subjects. The purpose of this study is to evaluate the clinical utility of 3D echo for serial assessment of LV mass regression in patients with uncontrolled hypertension following initiation of treatment. 20 consecutive patients (10F, 10M; ages 41 to 73 yrs) selected only for the presence of uncontrolled hypertension and increased septal and posterior wall thickness (_>1.2 cm) underwent 3D echo determination of LV mass at baseline, and after 6 and 12 weeks of antihypertensive therapy (Ca++channel blocker or ACEI and diuretics). 3D echo data sets of 8-10 short axis, non-parallel, non-intersecting cross-sections at end-diastole and end-systole were obtained using an acoustic spatial locater and a line of intersection display for guidance. Endocardial and epicardial boundaries were traced and volumes were computed. Mass index was calculated, Statistical analysis was carried out by repeated ANOVA using Tukey's test of the means. Results: Over the 12 week observation period there was a significant reduction of mass by 3D echo, p=0.0012, which was detected as early as 6 weeks following institution of drug therapy. The mean percent reduction of LV mass index by 6 weeks was 7.9% and by 12 weeks was 14.4%. Time mean Time Point Diff Betw 95% Point n index SD Comparison means C.I, 0 wks 20 74.9 14.9 II 0 -- 6 wks 5.95 _+5.27 6 wks 20 69.0 14.7 /I 0 -- i2 wks I0.76 .+5.58 I2 wks 16 64.2 12.9 II Conclusion: Serial 3D echocardiography is able to detect a 7.9% reduction of LV mass index in hypertensive patients 6 weeks after institution of treatment, Thus, 3D echocardiography is clinically useful for assessing regression of LV mass.
10D
AUTOMATED LEFT VENTRICULAR ENDOCARDIAL SURFACE DELINEATION USING 3D ECHOCARDIOGRAPHIC IMAGES AND KOHONEN NEURAL NETWORK. M Belohlavek MD, J Buithieu IVID,A Manduca Phi), DA Foley MD, T Behrenbeck MD PhD, JF GreenieafPhD, JB Seward MD. Mayo Clinic, Rochester, MN
Abstracts 387
12D
INCREASED LEFT VENTRICULAR M A S S BY 3D ECHO IN N O R M O T E N S I V E PATIENTS W I T H H Y P E R T E N S I V E RESPONSE T O E X E R C I S E Olakunie O. Akinboboye MD, Ruth Fernandez, Aasha S. OopaI MD, Zhanqing Shen MD, Donald C. Delisi, Matthew J. Schnellbaecher MD, David K. Blood MD, Donald L. King MD. Columbia University, New York, NY. Increased LV mass is the most significant predictor of cardiac morbidity and mortality except for age. One third of patients with hypertensive response to exercise (ExHBP) will progress to clinical hypertension within five years, however, the relationship of exercise induced hypertension to increased LV mass is unknown, The purpose of this study was to test the hypothesis that patients normotensive at rest but with hypertensive response to exercise have increased LV mass. 15 consecutive normotensive parle nts with atypical chest pain, negative treadmill stress test, and hypertensive response to exercise (systolic blood pressure increase with exercise >85 mm Hg in males and >60 mm Hg in females) were evaluated by 3D echo using a previously validated method for LV mass determination. Patients with documented coronary artery disease, valvular heart disease, diabetes, and abnormal resting ECG were excluded. 3D echo data sets of 8-10 non-parallel, unevenly spaced, non-intersecting short axis images were acquired using an acoustic spatial locater, line of intersection display and personal computer. Endocardial and epicardial boundaries were manually traced and volumes computed using a polyhedral surface reconstruction algorithm. Myocardial mass = myocardial volume x 1.05 g/ml, Mass was indexed to height2 (g/m2). Age and sex matched controls were drawn from a data base o f normal subjects whose LV mass had previously been determined by 3D echo. Data were analyzed to obtain range, mean, and standard deviation and the groups were compared using the unpaired T test. Results: m._..~n range mean mass index(g/m2) mass index(g/m2) _n mass (g) Control 10 111 g 28-52 g/m2 42 g/m2 ExHBP 15 157 g 38-68g/m2 54g/m2 The unpaired T test showed the two groups to be significantly different (T=-4.2, p<0.0004) Conclusion: Left ventricular mass index in nonnotensive patients with exercise induced hypertension is significantly increased in comparison to normal controls,
13D
WHAT IS A CLINICALLY S I G N I F I C A N T CHANGE OF LV EJECTION FRACTION BY 3D ECHO ? A DETERMINATION OF TEST-RETEST VARIABILITY Olakunle O. Akinboboye MD, Zhanqing Shen MD, Aasha S. Gopal MD, Matthew J. Schnellbaecher MD, Donald L. King MD. Columbia University, New York, New York. Reliable, serial, non-invasive measurement of left ventricular (LV) ejection fraction (EF) is essential for selecting and timing therapeutic nterventions. Three-dimensional echocardiography (3D ECHO) EF has previously been demonstrated to be comparable (F test, p=NS) to the radionuchde (MUGA) EF in the clinically relevant range of 3065%. The purpose of this study is to establish the test-retest variability of 3D ECHO for determination of LV EF, 22patients having clinically indicated MUGA underwent single data set 3D ECHO within 2 hours by two independent observers, one experienced (2 years) and one inexperienced (10 exam training set). Patients with MUGA EF _>70% were excluded because MUGA is imprecise above this level. Each observer performed two complete examinations in sequence. Between exams the patient sat up and was then re-positioned on the examination table. 8-10 short axis cross-sections of the LV were obtained using an acoustic spatial locater, line of intersection display and personal computer. The images were manually traced by the observer acquiring the exam. Volumes were computed by ventricular reconstruction and the EF calculated. Each observer was blinded to the other's results. 3D ECHO EF data were compared to MUGA EF by linear regression and limits of agreement analysis, Test-retest intraobserver and interobserver variability were calculated, Results: n = 22, EF range = 10-69%. Test - Retest Interobs Limits Intraobs r SEE Bias ~ Variab Vanab lnexp 0~97 4,4% -0.9% 9.1% ll.3%ofEF (combined) Exper 0,98 3.3% -0.6% 6.7% 4.7%ofEF 11.9% CONCLUSIONS: 3D ECHO EF is comparable to MUGA in the range i0-69% with high correlation, low variance, and no bias. 95% of the time 3D ECHO by an experienced observer will provide an EF within 6.7% of MUGA. With a single experienced observer test-retest intraobserver variability is very low. Thus, an EF change between two 3D ECHO examinations of greater than 9.4% (2 x 4.7%) obtained by the same experienced observer will be significant 95% of the time. 3D ECHO EF may be substituted for MUGA EF determination.
We have developed an initial working model of user-independent endocardial surface extraction which combines: [1] an algorithm for determining the probability of occurrence &the endocar~lium at certain image locations, and_J2] a higher level of processing represented by a Kohonen network. It effectively applies a priori shaoe an~t smootl~ness constraints to the data to generate the boundary surface approxamatton. Methods: We have combined previously developed algorithms for noise and speckle reduction with establishedtechniques for image gradient calculation. The endocardial ~radients were adiusted fdr angglar disparity with the vector direc%d from a user-ffesignated origin inside the left ventricular (LV) cavity. Each adjusted local ~radient provided the weighted probability nloccurrence of the LVendocardium at a particular image element location. This information was then present&l to a Kohonen neural net for LV endocardial delineation. Results: The Kohonen net automatically expands itself inside the LV cavity, generating a continuous smooth outline along areas with high probability of occurrence of the endocardium (figure). In areas of image dropout, the neural network makes logical assumptions of the endocardium location without escaping beyond endocaritial boundaries. Conclusions: Using a neural network, the LV cavity boundary can be delineated even in areas of image dropout. This 3D technique represents an important step in developing an accurate automated representation otthe LV cavity boundary for shape analysis and volume quantitation without geometric assumptmns. A 3D approach to a neural network is a unique advance in quantitative echocardiography.
Ao: aortaLV, RV: left,rightventricle
11D
Kohonennet: IS, TS: initial,tenninalstatus
C L I N I C A L USE OF 3D E C H O C A R D I O G R A P H Y FOR SERIAL ASSESSMENT OF LEFT VENTRICULAR MASS REGRESSION IN HYPERTENSIVE PATIENTS Aasha S. Gopal MD, Matthew J. Schnellbaecher MD, Zhanqing Shen MD, Andrew M. Keller MD, Olakunle O. Akinboboye MD, Peter M, Sapin MD, Donald L. King MD. Columbia University, NY, NY. Increased LV mass is an important, independent predictor of cardiac mortality. Measurement of its regression can be useful gauging the efficacy of therapy. LV mass computation by 3D echo has been validated and shown to be superior to 2D echo in normal subjects. The purpose of this study is to evaluate the clinical utility of 3D echo for serial assessment of LV mass regression in patients with uncontrolled hypertension following initiation of treatment. 20 consecutive patients (10F, 10M; ages 41 to 73 yrs) selected only for the presence of uncontrolled hypertension and increased septal and posterior wall thickness (_>1.2 cm) underwent 3D echo determination of LV mass at baseline, and after 6 and 12 weeks of antihypertensive therapy (Ca++channel blocker or ACEI and diuretics). 3D echo data sets of 8-10 short axis, non-parallel, non-intersecting cross-sections at end-diastole and end-systole were obtained using an acoustic spatial locater and a line of intersection display for guidance. Endocardial and epicardial boundaries were traced and volumes were computed. Mass index was calculated, Statistical analysis was carried out by repeated ANOVA using Tukey's test of the means. Results: Over the 12 week observation period there was a significant reduction of mass by 3D echo, p=0.0012, which was detected as early as 6 weeks following institution of drug therapy. The mean percent reduction of LV mass index by 6 weeks was 7.9% and by 12 weeks was 14.4%. Time mean Time Point Diff Betw 95% Point n index SD Comparison means C.I, 0 wks 20 74.9 14.9 II 0 -- 6 wks 5.95 _+5.27 6 wks 20 69.0 14.7 /I 0 -- i2 wks I0.76 .+5.58 I2 wks 16 64.2 12.9 II Conclusion: Serial 3D echocardiography is able to detect a 7.9% reduction of LV mass index in hypertensive patients 6 weeks after institution of treatment, Thus, 3D echocardiography is clinically useful for assessing regression of LV mass.