Integrated Backscatter Database

Taha Shaikh Cheng Yi Ph.D. Daniel Shindler M.D.

The images below depict the cyclic variation of integrated backscatter during periods of relaxation, stress, and recovery in individuals undergoing dobutamine stress echocardiography. The integrated backscatter was obtained from raw radiofrequency data reflected from the interventricular septum using the parasternal window. The data are not in phase with the cardiac cycle. A larger database is more than 300 k and will take long to download. It contains tables and links to graphs of 21 patients including the two patients shown below.

Patients undergoing dobutamine stress echocardiography were evaluated using the following method. Resting echocardiograms were performed using standard ultrasound equipment with arrangement to acquire raw radiofrequency ultrasound from a Hitachi EUB165 ultrasound machine. A 2.5 MHz transducer was applied to the chest, and images of the interventricular septum were obtained from the parasternal position. Radiofrequency ultrasound was acquired at rest, and the files were stored after being converted to digital format. As the dobutamine stress proceeded, radiofrequency information was again acquired at peak stress and the files saved as before. Finally, in the recovery period, once the heart rate had returned to normal, a third set of radiofrequency information was digitized in serial files. Integrated backscatter was then calculated in each file as a series of numbers. The tables show the mean integrated backscatter, standard deviation, maximum value, minimum value and range of each acquisition in individual patients. Each stage has an individual table and graph.

The graph images illustrate the temporal pattern of integrated backscatter during these three phases, namely, at rest (relaxed), during dobutamine stress, and in recovery. The radiofrequency ultrasound is displayed using an averaging technique demonstrating the variability between individual acquisitions in each stage as a three-dimensional graph.

It was initially attempted to synchronize the acquisition of radiofrequency ultrasound to the QRS complex of the surface electrocardiogram. This was not technically possible in all patients; hence, the graphs depict the variability of radiofrequency ultrasound through time, but do not begin at any particular point in the cardiac cycle.

Nevertheless, it is possible to discern in the graphs, the cyclic variability of the integrated backscattter.

The next three graphs and tables belong to a 72 year old female with resting antero septal left ventricular wall hypokinesis without evident thinning, scar or aneurysm. Two years prior to the study she suffered a non-Q wave anterior myocardial infarction. Cardiac catheterization at that time revealed a 40 percent proximal left anterior descending artery stenosis followed by a 95 percent mid left anterior descending artery stenosis. This second stenosis was sucessfully opened with balloon angioplasty.
Dobutamine-atropine stress showed limited improvement in contractility of the hypokinetic segment.

ID	STAGE	MEAN	STD	MAX	MIN	RANGE
s21	REST	327.65	80.55	450.45	0	450.45
s21	REST	200.53	91.05	412.09	18.98	393.11
s21	REST	296.95	138.69	653.61	28.74	624.87
s21	REST	670.66	128.21	965.82	153.33	812.49

ID	STAGE	MEAN	STD	MAX	MIN	RANGE
s21	STRESS	3908.67	1184.1	5509.52	300.69	5208.83
s21	STRESS	1455.31	459.63	2389.38	283.83	2105.55
s21	STRESS	2415.51	581.13	3491.31	460.04	3031.27
s21	STRESS	3762.71	1358.32	5762.51	596.85	5165.66
s21	STRESS	4266.42	972.6	6204.78	772.43	5432.35

ID	STAGE	MEAN	STD	MAX	MIN	RANGE
s21	RECOVERY	2513.68	544.14	3917.37	540.78	3376.59
s21	RECOVERY	1974.6	644.7	3415.28	375.2	3040.08
s21	RECOVERY	1858.86	644.8	3589.78	567.92	3021.86
s21	RECOVERY	8091.63	3662.32	15853.7	437.74	15416.0
s21	RECOVERY	183.85	30.83	252.62	47.5	205.12
s21	RECOVERY	3119.61	965.34	5077.45	359.19	4718.26
s21	RECOVERY	194.44	73.97	434.97	34.32	400.65

The next three graphs and tables belong to a 77 year old male with history of prior anterior wall myocardial infarction fifteen years ago. He suffered from Class III NYHA congestive heart failure. He was admitted for new onset of exertional chest pain.
Coronary arteriography showed a normal left main, the left anterior descending artery had a total proximal occlusion, the left circumflex artery had a 40 percent proximal occlusion, the obtuse marginal artery was totally occluded, the right coronary artery was dominant with a 90 percent proximal stenosis.
Dobutamine stress echo showed akinesis and increased reflectivity of the antero septal left ventricular wall from which the integrated backscatter was calculated. There was no improvement in contractility with dobutamine stress.

ID	STAGE	MEAN	STD	MAX	MIN	RANGE
d15	REST	28443	9043.56	49653.0	0	49653.0
d15	REST	32653.7	12238.6	58717.7	4382.1	54335.6
d15	REST	44729.6	19564.5	82195.1	5189.1	77006.0
d15	REST	20335.1	10720.5	39485.0	4404.26	35080.7
d15	REST	47748.4	14509.2	68912.6	6014.42	62898.2
d15	REST	41205.4	13619.7	61357.5	3070.82	58286.7
d15	REST	39956.1	21310.1	70217.84	1700.27	58517.5

ID	STAGE	MEAN	STD	MAX	MIN	RANGE
d15	STRESS	14095.5	4096.83	21348.7	2524.29	18824.4
d15	STRESS	12547.2	2676.35	17377.5	2984.8	14392.7
d15	STRESS	20587.8	9478.29	43444.6	2373.45	41071.1
d15	STRESS	21837.6	8005.51	38665.2	3202.7	35462.5
d15	STRESS	15056.6	4646.16	24078.4	2426.36	21652.0
d15	STRESS	20221.9	4447.95	31388.0	5369.54	26018.5
d15	STRESS	19808.1	6231.91	33376.7	2850.81	30525.9
d15	STRESS	16504.0	7209.67	35708.3	3275.11	32433.2
d15	STRESS	14297.7	3412	19465.3	1767.92	17697.4
d15	STRESS	16239.7	4003.77	25059.7	2495.59	22564.1

ID	STAGE	MEAN	STD	MAX	MIN	RANGE
d15	RECOVERY	16290.6	8776.86	30074.0	1112.97	28961.1
d15	RECOVERY	23742.2	11389.0	46489.6	2589.61	43900.0
d15	RECOVERY	30075.6	11894.6	56281.7	6399.1	49882.6
d15	RECOVERY	8188.83	3335.9	13577.0	2231.21	11345.8
d15	RECOVERY	4957.99	2106.2	9556.87	1185.7	8371.17
d15	RECOVERY	2363.88	1023.33	4628.62	209.05	4419.57

The contents and links on this page were last verified on December 10, 1998.

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