Left ventricular thrombus and systemic emboli complicating the cardiomyopathy of Duchenne's muscular dystrophy.

A 17-year-old boy with Duchenne's muscular dystrophy and congestive cardiomyopathy with a left ventricular thrombus is described. The patient presented with flank pain, and computed tomography of the abdomen revealed multiple bilateral renal infarcts. An echocardiogram delineated a left ventricular thrombus and generalized hypokinesis with a left ventricular ejection fraction of 25%. Heparin therapy was started, but the patient died of refractory congestive heart failure. Autopsy revealed diffuse skeletal myopathy consistent with Duchenne's muscular dystrophy as well as biventricular cardiomyopathy with a recent left ventricular apical-septal mural thrombus. Right atrial thrombus, a left upper lobe pulmonary embolus, and splenic and renal infarcts were also noted. To our knowledge, this is the first reported case of left ventricular thrombus with or without systemic emboli in the cardiomyopathy of Duchenne's muscular dystrophy.

Measurement variability of carotid atherosclerosis: real-time (B-mode) ultrasonography and angiography.

To quantify the within- and between-reader agreement of carotid B-mode ultrasonography and angiography interpretation, images from 117 patients examined by both modalities were read multiple times. Angiographic measurements were more reproducible than those of B-mode scans for all parameters except lesion width, but variations for B-mode scan measurements were similar to those for angiographic measurements. Within-reader agreement on the presence of ulceration was substantial for both modalities, whereas between-reader agreement was poor for B-mode scan and only moderate for angiography.

Doppler ultrasound in aortic stenosis: in vitro studies of pressure gradient determination.

Torricelli's equation expresses a simple relationship between fluid velocity and pressure gradient in orifice flow and is currently used in conjunction with noninvasive Doppler ultrasound to determine gradients in mitral stenosis, and aortic stenosis, as well as other cardiovascular orifices. In theory, however, the Torricelli equation overestimates the gradient in aortic stenosis and the Borda equation should be more applicable. A brief tutorial derivation of the Borda and Torricelli equations is presented. The applicability of Torricelli's equation in aortic stenosis was studied experimentally with a rigid wall, pulsatile flow analogue. Doppler ultrasound and manometric data were collected simultaneously. Percent stenosis, peak flow rate and fluid viscosity were varied. The results demonstrated that the Torricelli equation consistently overestimated the pressure gradient. At 61% area stenosis, the overestimation exceeded 100%. In vivo studies are required to determine the relevance of the observations to clinical situations.

Left coronary arterial blood flow: noninvasive detection by Doppler US.

Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs.

Doppler ultrasound in orifice flow. In vitro studies of the relationship between pressure difference and fluid velocity.

The validity of an orifice equation (Torricelli's law) which expresses a simple relationship between the pressure difference across an orifice and the maximum fluid velocity in the orifice was tested in vitro. An aqueous suspension of barium sulfate particles with a polymer added to attain variations in viscosity, was forced through orifices which ranged in diameter from 0.4 to 4.7 mm. The pressure difference across the orifice was determined with a transducer and the maximum fluid velocity in the orifice was determined with Doppler ultrasound. Tests were performed at Reynolds numbers, fluid viscosities, and pressure differences that spanned the following ranges: 400-25,000, 1-5 cP, and 3-100 mmHg, respectively. At pressure differences larger than 3 mmHg and fluid viscosity 3 cP (approximate viscosity of in vivo blood), Torricelli's law was demonstrated to be valid for orifice diameters larger than 1.6 mm. The validity of the law was found to be relatively insensitive to variations in orifice length.

Representations of rapidly oscillating structures on the Doppler display.

In cardiovascular applications of Doppler ultrasound, oscillating structures are at times within the sample volume of the transducer. When the period of oscillation is shorter than the time window of the Fourier transform, the velocities of the structure are not resolved in time by the frequency analyzer. The resulting display can differ considerably from that obtained from structures with linear velocities. The investigation characterizes this phenomenon with the use of theoretical relations, mechanical model experiments and patient data. The results demonstrate that the representations of rapidly oscillating structures on the Doppler display can be interpreted in terms of frequency of oscillation and also, to some extent, in terms of maximum displacement of the structure.

CW and pulsed Doppler echocardiography utilizing a stand-alone system.

An independent directional Doppler system operating in pulsed or continuous-wave mode and a real-time spectral analyzer with a 3 ms temporal resolution have been used to supplement conventional real-time and M-mode echocardiography. Examination techniques as well as findings in normal and abnormal hearts are presented. Continuous-wave Doppler is most useful for detection of peak frequency shifts for calculation of valvular gradients while pulsed Doppler is superior in the detection of small jets of abnormal flow and in display of spectral broadening. Real-time spectral analysis allows interactive selection of peak frequency shifts, can separate coincident flows by signal intensity and depicts high frequency valvular movements to rival the capabilities of M-mode.

Is routine angiography necessary prior to carotid endarterectomy?

The records of 111 consecutive patients undergoing evaluation for possible carotid endarterectomy at the University of Rochester were reviewed. All patients had noninvasive evaluation (oculoplethysmography-Gee and direct, continuous-wave Doppler ultrasonography) as well as selective carotid angiography. Patients were grouped by clinical presentation to ascertain the relative importance of angiography in determining the need for surgery. Arteriography added nothing to clinical and noninvasive evaluation in over two thirds of patients with hemispheric cerebral symptoms or asymptomatic carotid bruits. In contrast, we found that almost all patients with nonhemispheric symptoms required angiography for adequate evaluation prior to surgery. The implication of these findings on preoperative evaluation of patients with carotid surgery is discussed.

Frequency-dependent angle scattering of ultrasound by liver.

Ultrasonic scattering by one specimen of normal pig liver and two specimens of abnormal human liver has been measured as a function of angle and frequency at each angular position of transmit and receive transducers which were rotated in equal and opposite directions about the axis of a cylindrically shaped tissue sample. Mean data values were determined by averaging points at like frequencies and angular positions in scans made at intervals along the axis of the specimen. Sections of the specimens were obtained throughout its length and stained to emphasize structures containing collagen and connective tissue shown by acoustic microscopy to produce sound speed variations which are known to cause scattering. Using the stained sections as diffraction screens, calculations of scattering were carried out via Fourier transforms on a scale comparable to that in the acoustic studies for comparison with the acoustic data. In all specimens studied, mean acoustic scattering exhibited a general decrease in level with increasing scattering angle. The rate of decrease in acoustic scattering with angle agreed qualitatively with the calculations of average angular falloff of scattering by the stained sections. Lower rates of decrease were observed in tissues with more closely spaced collagen containing structures. Although the data derived from the few substantially different specimens studied is not intended to be representative of all liver, the results show a qualitative correspondence between acoustic scattering and visual appearance which depends on tissue components and their arrangement.

Automated water-path ultrasonic examination of scrotum.

A new method of examining the scrotum by ultrasound with an automated water-path scanner is described. This method allows immobility of the scrotum in a more acceptable and painless way than in contact scanning methods. Panoramic scans of the entire scrotum and precision tomographic plane placement are advantages over conventional techniques. A description of normal scrotal anatomy includes the mediastinum of the testis, an important scrotal landmark. Representative cases of benign and malignant scrotal disease are presented to emphasize the utility of water-path scanning.

Echocardiographic evaluation of cardiac abnormalities in Duchenne's dystrophy and myotonic muscular dystrophy.

Routine echocardiographic examinations were performed on 53 individuals with muscular dystrophy (29 with myotonic muscular dystrophy [MMD] and 24 with Duchenne's dystrophy [DD]). Five of 29 (17%) with MMD and six of 24 (25%) with DD had typical mitral valve prolapse evidenced by echocardiography. All patients with DD and mitral valve prolapse had severe thoracic skeletal deformities, while none with MMD and mitral valve prolapse had such abnormalities. Other echocardiographic parameters analyzed included the fractional shortening of the left ventricle (% delta S), excursions of the left ventricular posterior wall (LVPW) and the ventricular septum, pre-ejection period/left ventricular ejection time ratios (PEP/LVET), and thickness of the LVPW and ventricular septum. Abnormal prolongation of the PEP/LVET ratio and increased thicknesses of the LVPW and ventricular septum were noted in some individuals in the MMD group. Decreased % delta S with diminished excursion and diastolic velocity of the LVPW were noted in some with DD.

New techniques in cardiac imaging with ultrasound: state of the art.

Two-dimensional real-time ultrasonic imaging in the diagnosis of acquired and congenital cardiac lesions is reviewed. This technique provides anatomically correct cross-sectional images and demonstrates movements of valve leaflets and segments of heart walls. The imaging of blood flow through the use of ultrasonic contrast agents and the application of pulsed Doppler principles is also reviewed, and future trends are discussed.

Echogenic fluid: a pitfall in the ultrasonographic diagnosis of cystic lesions.

Although it is well known that biliary sludge can produce fine diffuse echoes within the gallbladder, it is less commonly appreciated that other cystic structures may contain echogenic fluid and therefore be mistaken sonographically for solid lesions. In this article three cases of splenic cysts and one case each of pyrometrocolpos, hydroureter, and pyonephrosis presented with diffuse fine echoes in the fluid. Three of these cases were misinterpreted as a result of this echogenic appearance. These cases serve to emphasize the need for awareness of the echogenicity of some types of fluid and the value of other signs of cystic lesions besides absence of internal echoes.

Limitations in the echocardiographic assessment of aortic root dimensions in the presence of aortic valve disease.

Aortic root M-mode echocardiograms were evaluated in 79 patients who had aortic valve replacement. Echocardiographic measurements of aortic root dimensions correlated poorly with surgical estimates. Inclusion of a portion of the sinuses of Valsalva in the former set of estimates probably accounts for this discrepancy.