Ultrasound Image Modality - Assignment Example

Ultrasound Image Modality Colour Flow Doppler Created from a colour flow Doppler ultrasound are coloured wavelengths or frequencies displayed on top of the B-mode image. The imaging from a colour flow Doppler applies pulsed wave ultrasound. The procedural action of colour flow and pulsed wave Dopplers varies. The average Doppler shift measured from thousands of signals on a given plane is encoded as red for positive Doppler shifts moving towards the transducer and blue for negative Doppler shifts moving away from the transducer. The simultaneous combination of B-mode signals and colour flow images produces a colour pixel overlaid on the B-mode image. Colour flow imaging uses high-intensity pulse wavelengths that are 3 – 4 times longer than B-mode image pulses, with an equivalent spatial resolution decrease.1 Use of Three-Dimensional Colour Flow Doppler for the Assessment of Mitral Regurgitation In previous clinical trials, gray scale version of three-dimensional displays has been recreated to determine mitral regurgitation. Regurgitant mitral flow jets could hardly be differentiated from adjoining structures of the heart. A regurgitant mitral flow displayed in colour-coded three-dimensional image was developed but eventually proved to be ineffective because the display failed to incorporate cardiac structures. Failure of the regurgitant flow to supply spatial information, jet origin and its course of action led to the reconstruction of a more enhanced coloured 3D regurgitant jet by transesophageal approach with Doppler colour flow mapping that displayed a combination of gray scale and colour flow information. OBJECTIVE: To reveal the possibility of three-dimensional recreation of regurgitant mitral flow jets using the new method of colour programmed digitized statistics obtained through transesophageal echocardiography (TEE). METHOD: 46 patients with detected mitral regurgitation on a prior transthoracic study and undergoing transesophageal echocardiography were evaluated. Patients with atrial fibrillation were not excluded from standard procedures. To measure regurgitant flow in 3D, a commercial ultrasound imaging system with a TEE probe was used. An alternation approach of data collection was employed for two-dimensional colour flow images at 3-degree spaces above 180 degrees. Three-dimensional colour flow jets were showed alongside gray scale information of the surrounding structures of the heart. RESULTS: Mitral regurgitant flow was effectively redone in all patients. The flow was displayed in the left atrial and two longitudinal courses. The total procedural time ranged between 10 and 15 minutes. 28 jets were essentially directed and 15 had unusual injuries. Out of the 46 patients, eight of them had periprosthetic mitral regurgitant flow. CONCLUSIONS: The possibility of 3D imaging of mitral regurgitant jets in most patients was proven. The use of the 3D colour flow Doppler through transesophageal echocardiography presents supplementary records than the two-dimensional test. It gives better data on the cause and degree of lesions, plus information on jet trajectories, predominantly in patients with paravalvular discharges. Moreover, this new technique defeats the natural restrictions of 2D echo Doppler, particularly in patients with unusual mitral regurgitation, by illustrating the maximum directions of jet flow.2 Continuous Wave Doppler Continuous wave Doppler applies continuous ultrasound generation together with continuous ultrasound reception. Doppler signals are achieved from all blood vessels that lie along the ultrasound beam’s pathway. Two disadvantages of the continuous wave Doppler ultrasound are its inability to establish the exact position of velocities along the ultrasound beam and its inability to create colour flow images. Availability of a comparatively low-cost Doppler ultrasound instruments use continuous wave probes able to supply Doppler signals with B-mode image exclusion. More popular use of continuous wave Doppler coupled with adult cardiac scanners is for the examination of high aortic velocities.3 Evaluation of Aortic Stenosis by Continuous Wave Doppler Ultrasound Aortic stenosis is the blood flow obstruction across the aortic valve. Aortic stenosis can be caused by congenital unicuspid or bicuspid valve, degenerative hardening of the valve, and rheumatic fever.4 Studies of the association of aortic valve gradient verified by continuous wave Doppler ultrasound and that verified at catheterization procedure have always been evaluated in nonconcurring calculations. An assessment from instantaneous continuous wave Doppler ultrasound and catheter measurements of pressure gradient in 44 adult patients was observed. OBJECTIVE: To detect the presence of aortic stenosis with the use of a noninvasive continuous wave Doppler. METHOD: Forty-four patients were assigned to a group: 24 patients with suspected aortic stenosis as Group A; and 20 healthy patients in Group B. Both groups were evaluated noninvasively by continuous wave Doppler ultrasound before cardiac catheterization procedure. Group A: Maximal velocity dimensions in ascending aorta = 3.0 to 5.8 m/s (mean 4.34 +/- 0.65 Group B: Maximal velocity dimensions in ascending aorta = 1.0 to 1.6 m/s (mean 1.28 +/- 0.16) From the maximal velocity in Group A patients, the peak and mean pressure gradients crosswise the aortic valve were computed using the Bernoulli equation. RESULTS: The parallel correlations with the peak aortic valve gradient was achieved at cardiac catheterization (r = 0.79). In 20 patients belonging to Group A, the peak Doppler gradient was within one-fourth of the gradient derived at cardiac catheterization. Three patients were detected with high aortic stenosis. There was also an under-estimation of aortic valve gradient by slightly over one-fourth of the gradient in those 3 patients. The Doppler study was unsuccessful in determining significant aortic stenosis in just one patient. A considerable overestimation of the aortic valve gradient through the continuous wave Doppler ultrasound was not seen in all patients. CONCLUSION: The CW Doppler method was principally useful in older patients with questionable results frequently yielded from other noninvasive examinations. A rare but crucial drawback of the technique is gradient underestimation transpiring when the direction of occurrence involving the ultrasound beam and aortic blood flow is excessive. The results show that continuous wave Doppler ultrasound can be used to unfailingly detect the pressure gradient in aortic stenosis patients.5 M-Mode Imaging The application of M-mode or Motion-mode ultrasound is usually used in cardiac and fetal cardiac imaging. Also called time-motion or TM-mode, it is useful for quantifying single dimensions of cardiac walls and chambers. The transducer beam of M-mode ultrasound is unmoving even as the signals from a moving anatomical structure are collected at different points. A particular beam in a sonographic examination is applied to create the one-dimensional M-mode picture, where motion from a body part, for example a heart valve, can be recorded as wavelength or frequency illustrations. The elevated sample frequency of up to one thousand pulses per second is functional in the measurement of pace and movement, mainly in cardiac structures, for example, the cardiac valves and the chamber walls.6 Diaphragm Movement in Pre-Cholecystectomy and Post-Cholecystectomy Using M-Mode Ultrasound Disorders of the respiratory tract in post-surgical procedure of the abdomen are given the usual explanation of alterations in diaphragmatic movement that are hardly certain and scientific. The purpose of this study is to measure these alterations by means of a noninvasive process. M-mode ultrasound is employed for the feasible calculations of diaphragmatic amplitude in 14 patients before and after cholecystectomy. Cholecystectomy may cause damaged respiratory and diaphragmatic dysfunctions. At present, the methods employed to study these effects are equally restraining and lengthy. The sonographic method this study applied is entirely nonrestrictive and can determine respiratory morphology and real-time movement. OBJECTIVE: To assess the assumption that respiratory performance and diaphragmatic activity are weakened after cholecystectomy. METHOD: Fourteen adult patients were investigated: 7 patients undergoing elective cholecystectomy (5 women, 2 men; with age range of 34 to 69 years old) and 7 other patients undergoing open cholecystectomy (5 women, 2 men; with age range of 28 to 72 years old). All patients were physically fit with no symptoms of cardio-respiratory disease. Smoking and obese patients, as well as those who had thoracic surgery, were disqualified from participating in the study. Every patient was carefully monitored for signs of respiratory or neuromuscular inconsistencies. A sector-scanning ultrasound system equipped with curved array probe was used, together with a B-mode to find the two-dimensional cross-section with the best angular approach; and an M-mode to demonstrate the movement of the body organ. The M-mode examined only the right side of the diaphragm while the B-mode examined only the left side. The line produced by signals initiated from the diaphragm moved up and down on the M-mode graph. The M-mode ultrasound was displayed on the LCD and constantly captured on videotape. The ultrasound technique can be reproduced and measurements are less isolated than those of radioscopy.7 The study was done a day before and a day after cholecystectomy. Lying in a semisupine position, with nose clipped, the patient was requested to breathe quietly for 10 minutes, through a mouthpiece attached to the pneumotachograph, before measurements were completed. Activities of the diaphragm were later documented in Motion-mode, while instantaneous B-mode imaging sustained a steady direction of frequency. Simultaneous records of spirometric statistics during silent breathing and during deep stimulations were confirmed. Patients were then requested to breathe in very deeply. This movement was observed in real time with the on-screen ultrasound tracing, which permitted exact startup and stop of the inspiration. RESULTS: Using M-mode ultrasound method, alterations in diaphragmatic movements before and after surgery were illustrated. This study exhibited a post-surgery reduction of the magnitude of diaphragm excursion throughout silent and deep inspiration, alongside an elevation in breathing speed both before and after cholecystectomy. In the course of the study, there were no instances of pneumonia after the surgery, no supplemental oxygen needed, and no development of respiratory inconsistencies. M-mode ultrasound provides immediate illustration of diaphragm movements in real-time. The noninvasive and nonrestricting process of M-mode ultrasound can be simply joined with supplementary techniques: pressure and airflow measurement, for a total assessment of respiratory irregularities after cholecystectomy and relative studies. M-mode ultrasound is comparatively trouble-free and generally accessible. New models of portable M-mode sonographs can perform the procedure at the patient’s bedside. In this study, M-mode sonographic technique recommends a realistic way for the assessment of postoperative diaphragmatic dysfunctions.8 Notes 1.Colin Deane, “Doppler Ultrasound: Principles and Practice,” Centrus (2002), http://www.centrus.com.br/DiplomaFMF/SeriesFMF/doppler/capitulos-html/chapter_01.htm (accessed 28 October 2010). 2. Lissa Sugeng, et al, “Dynamic three-dimensional color flow Doppler: an improved technique for the assessment of mitral regurgitation,” Echocardiography (Mount Kisco: N.Y) vol. 38, no. 2 (2003): 265-73. 3. Deane, 2002. 4. Jerry Balentine, “Aortic Stenosis,” Medscape (2010), http://emedicine.medscape.com/article/757200-overview (accessed 28 October 2010). 5. Marvin Berger, et al, “Evaluation of aortic stenosis by continuous wave Doppler ultrasound,” Journal of the American College of Cardiology, (1984) 3:150-156 6. “M-Mode,” Ultrasound – Technology Information Portal (2010), http://www.us-tip.com/serv1.php?dbs=M-Mode&type=db1 (accessed 28 October 2010). 7. Jean Ayoub, et al, “Non-invasive quantification of diaphragm kinetics using M-mode sonography,” Canadian Journal of Anesthesia (1997) 44: 739–44. 8. Jean Ayoub, et al, “Diaphragm Movement Before and After Cholecystectomy: A Sonographic Study,” Anesthesia and Analgesia, vol. 92, no. 3 (2001): 755-761. Bibliography Ayoub, Jean et al. “Non-invasive quantification of diaphragm kinetics using M-mode Sonography.” Canadian Journal of Anesthesia (1997) 44: 739–44. Ayoub, Jean et al. “Diaphragm Movement Before and After Cholecystectomy: A Sonographic Study.” Anesthesia and Analgesia. vol. 92, no. 3 (2001): 755-761. Balentine, Jerry. “Aortic Stenosis.” Medscape. (2010). http://emedicine.medscape.com/article/757200-overview (accessed 28 October 2010). Berger, Marvin. “Evaluation of aortic stenosis by continuous wave Doppler ultrasound.” Journal of the American College of Cardiology. (1984) 3:150-156. Deane, Colin. “Doppler Ultrasound: Principles and Practice.” Centrus (2002). http://www.centrus.com.br/DiplomaFMF/SeriesFMF/doppler/capitulos-html/chapter_01.htm (accessed 28 October 2010). “M-Mode.” Ultrasound – Technology Information Portal (2010). http://www.us-tip.com/serv1.php?dbs=M-Mode&type=db1 (accessed 28 October 2010). Sugeng, Lissa et al. “Dynamic three-dimensional color flow Doppler: an improved technique for the assessment of mitral regurgitation.” Echocardiography (Mount Kisco: New York) vol. 38, no. 2 (2003): 265-73. Read More