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Biomedical subjects

J Yoshikawa

Publications and source records attributed to J Yoshikawa.

At least 325 records · Page 18Linked to original sources

[Imaging diagnosis of hepatocellular carcinomas].

With the rapid progress of various imaging methods, including ultrasonography (US), computed tomography. (CT), digital subtraction angiography (DSA) and magnetic resonance imaging (MRI), it has become possible to detect small liver cancer less than 2 cm in diameter, and the prognosis of hepatocellular carcinomas is now improving rapidly. However, the accurate detection of smaller lesions about 1 cm in diameter and their differential diagnosis are difficult by conventional imaging methods such as US, CT and arteriography. For this purpose, we stressed the effectiveness of the combined use of CT and arteriography (the so-called CT arteriography), CT during arterial portography or Lipiodol CT. The promising future of MRI in this field is also discussed.

Appointments and Schedules↗

[Transesophageal echocardiographic findings of mitral valve prolapse].

Transesophageal echocardiography (TEE) is a new approach to the investigation of the heart, at a closer range without interference from lung tissue or ribs. In this study, we evaluated 15 patients with mitral valve prolapse by TEE. All patients had a pansystolic murmur and severe mitral regurgitation by left ventriculography. Seven patients underwent cardiac surgery. The presence of ruptured chordae tendineae was confirmed in all these patients at the time of operation. The transesophageal echocardiographic finding of mitral valve prolapse was a circular or coiled cusp or whip-like protrusion of a scallop into the left atrium in systole. TEE disclosed ruptured chordae tendineae in all of the seven patients with ruptured chordae tendineae confirmed by surgery, whereas transthoracic echocardiography disclosed only one. In the remaining patients, TEE disclosed chordal rupture in six. The prolapsed sites by TEE were coincident with those by cardiac surgery in each patient. By three-dimensional construction of the mitral valve using TEE, the direction of mitral regurgitant jet was correctly visualized. In conclusion, TEE is useful in evaluating patients with mitral valve prolapse and is a sensitive method for detecting ruptured chordae tendineae.

Chordae Tendineae↗

[Silent severe tricuspid regurgitation: a study by Doppler echocardiography].

Sixty-eight patients with severe tricuspid regurgitation proven by right ventriculography were examined using pulsed and continuous wave Doppler echocardiography and color Doppler flow imaging. Among the 68 patients, there was no tricuspid regurgitant murmur in 16 (24%) in whom laminar regurgitant flow signals were demonstrated by pulsed Doppler echocardiography. The area in which laminar flow was detected ranged from 8 to 46 mm2 (mean 19.5 +/- 9.8 mm2). The peak velocities in patients without regurgitant murmurs as measured by continuous wave Doppler echocardiography ranged from 1.1 to 1.9 m/sec (mean: 1.61 +/- 0.21 m/sec). Laminar regurgitant flow signals were obtained in six; and turbulent regurgitant flow signals in 46 of 52 patients with tricuspid regurgitant murmurs, and their peak velocities ranged from 1.7 to 5.1 m/sec (2.80 +/- 0.78 m/sec). The peak velocities of the regurgitant flow signals in patients without tricuspid regurgitant murmurs were significantly lower than those in patients with regurgitant murmurs (p less than 0.01). In six patients with laminar regurgitant flow signals and regurgitant murmurs, the areas of laminar flow signals ranged from 3 to 12 mm2 (mean 7.0 +/- 3.5 mm2) and were smaller than those of patients without regurgitant murmurs (p less than 0.001). A characteristic candle flame pattern of regurgitant flow signals was observed in all patients without murmurs. Thus, the absence of a tricuspid regurgitant murmur results from laminar regurgitant flow signals of low velocity and this is characterized by a candle flame pattern using color Doppler flow imaging.

Adolescent↗

[Doppler techniques in the detection of valvular regurgitation: their value and limitations].

To evaluate the clinical value of various Doppler techniques in detecting valvular regurgitation, we compared the sensitivity, timing and duration of regurgitation, and the peak velocity of regurgitant signals among conventional pulsed Doppler, color Doppler, continuous wave Doppler and HPRF Doppler echocardiography. 1. Sensitivity of Doppler techniques in detecting mitral regurgitation: Among fifty patients with mitral regurgitation confirmed by left ventriculography, mitral regurgitation was detected in 48 (96%) using color Doppler and pulsed Doppler echocardiography; in 41 (82%) by HPRF Doppler; and in 37 (74%) by continuous wave Doppler echocardiography. In 103 consecutive normal volunteers, mitral regurgitant signals were detected in 46 (45%) by color Doppler, in 39 (38%) by pulsed Doppler, in 16 (16%) by HPRF Doppler, and in 8 (8%) by continuous wave Doppler echocardiography. 2. Timing and duration of regurgitant signals: To assess the timing and duration of regurgitant signals, 43 patients with regurgitant signals of short duration during systole or diastole were studied using M-mode color Doppler echocardiography. Using the latter method, regurgitant signals throughout systole and the isovolumic relaxation period could be demonstrated in all but four patients who had regurgitant signals of short duration during systole, but suggesting mitral or tricuspid regurgitation. In all patients with regurgitant signals of short duration during diastole, aortic or pulmonary regurgitant signals throughout diastole could be demonstrated with M-mode color Doppler echocardiography. Thus, this technique is superior to conventional pulsed Doppler echocardiography for detecting accurate timing and duration of valvular regurgitation. 3. Peak velocity of regurgitant flow: To compare the peak velocity of regurgitant flow by continuous wave Doppler and by HPRF Doppler echocardiography, 20 patients with mitral regurgitation and 22 patients with tricuspid regurgitation were examined using the both methods. In patients with severe mitral regurgitation, the peak velocity detected by HPRF Doppler echocardiography correlated well (r = 0.96) with that detected by continuous wave Doppler echocardiography. However, in patients with mild mitral regurgitation, the peak velocity detected by HPRF Doppler echocardiography was higher than that detected by continuous wave Doppler echocardiography. In patients with severe tricuspid regurgitation, the peak velocity had a close correlation (r = 0.99) with the both techniques. In patients with mild tricuspid regurgitation, the peak velocity was higher by HPRF than by continuous wave Doppler echocardiography. In conclusion, color or pulsed Doppler echocardiography should be used for detecting valvular regurgitation. M-mode color Doppler echocardiography is superior to conventional pulsed Doppler echocardiography for detecting timing and duration of valvular regurgitation.(ABSTRACT TRUNCATED AT 400 WORDS)

Echocardiography, Doppler↗

Improved diagnosis and characterization of left ventricular pseudoaneurysm by Doppler color flow imaging.

Three patients with a left ventricular pseudoaneurysm are presented. Doppler color flow imaging helped to establish the diagnosis and was able to show additional blood flow abnormalities. The guided continuous wave Doppler interrogation of the shunting blood flow through the communication between the pseudoaneurysm and the left ventricle allowed the identification of a specific diagnostic flow pattern. Doppler color flow imaging offers advantages in patients with equivocal two-dimensional echocardiographic findings for elucidating confusing clinical findings and demonstrating additional and unsuspected flow abnormalities.

Aged↗

Color Doppler evaluation of valvular regurgitation in normal subjects.

To determine prospectively the prevalence of mitral, aortic, tricuspid, and pulmonary regurgitation in normal persons, 211 consecutive, apparently healthy volunteers were examined with a color Doppler flow imaging system. The subjects were divided into five age groups (group 1, 6-9 years old; group 2, 10-19 years old, group 3, 20-29 years old, group 4, 30-39 years old, and group 5, 40-49 years old). The prevalence rate of mitral regurgitation in the normal subjects was 38-45% in each group. The mitral regurgitant jets came from the posteromedial commissure in all but two subjects. No aortic regurgitant flow signals were detected in the normal subjects. Tricuspid regurgitation was detected in 15-77% in each group, and pulmonary regurgitation was detected in 28-88%. Regarding the tricuspid and pulmonic valves, the prevalence rate of regurgitation is age dependent (p less than 0.01) and tends toward the lower rate in groups over the age of 30 years. The tricuspid and pulmonary regurgitant jets came from the center of the coaptation of each valve. The area of the regurgitant jet signals in normal persons was significantly smaller (p less than 0.001) than that obtained from patients with organic valve disease. Our study shows that in a large proportion of normal persons under the age of 50 years color Doppler echocardiography permits recording of regurgitant signals behind all valves except the aortic. In conclusion, one should be aware of the existence and characteristics of regurgitation in normal persons when evaluating valvular regurgitation by Doppler techniques.

Adolescent↗

Problems in the management of elderly patients with valvular heart disease.

One hundred and nine patients over the age of 65 years with valvular heart disease have been reviewed. Of these, 57 patients were treated medically (medical group) and the remaining 52 patients underwent valve surgery (surgical group). Of the 57 patients who were treated medically, 46 (81%) were in NYHA Functional Class I or II, 7 were in Class III, and 4 were in Class IV. Among these, there were 8 deaths. The 5 year survival rate of the medical group, calculated by the actuarial method, was 90 +/- 5%. Eight patients had a nonfatal cerebrovascular accident. Of the 52 elderly patients who underwent valve surgery, 20 were in NYHA Functional Class II, 21 were in Class III, and 11 were in Class IV. Of these, there were 5 operative deaths (9.6%). Four patients died of postoperative low cardiac output syndrome and renal failure. One died of intraoperative aortic dissection. Of the 470 patients under the age of 65 years, there were 15 operative deaths (3.2%). Forty-one of the 47 hospital survivors have improved their cardiac functional classification, while 6 patients have remained in the same class as preoperatively. The average NYHA Class prior to operation was 2.7 improved to Class 1.3 after operation. The 3 year survival rate of the surgical group, calculated by the actuarial method, was 81 +/- 6%. Thus, the prognosis of asymptomatic elderly patients is good. Although operative mortality for the symptomatic elderly patients is relatively high, valve surgery can be performed with a satisfactory prognostic outlook.

Actuarial Analysis↗

Fatty metamorphosis in hepatocellular carcinoma: radiologic features in 10 cases.

We describe the sonographic, CT and angiographic findings in 10 cases of hepatocellular carcinoma in which extensive fatty metamorphosis occurred within the tumors. Fatty change was diffuse in smaller tumors (less than 3.5 cm) and focal in larger tumors (greater than 3.5 cm). Fatty metamorphosis characteristically caused a low-attenuation area on CT (less than -10 H) and a highly echogenic area on sonography. The sonographic appearance of small hepatocellular carcinomas with fatty metamorphosis was identical to the findings in cavernous hemangioma or focal fatty change of the liver. CT correctly revealed the presence of fat in these hepatocellular carcinomas. In these cases, hepatic arteriography showed no tumor stain; however, CT arteriography (dynamic CT during injection of contrast medium into the hepatic artery) was useful in showing the tumor, its capsule, and its internal septa. In the diagnosis of large hepatocellular carcinoma, the presence of intratumoral fat is not likely to be problematic, but small tumors that are diffusely infiltrated by fat must be distinguished from such benign conditions as focal fatty change, lipoma, and angiomyolipoma.

Aged↗

[Late complications of valve replacement: the benefits of non-invasive assessment].

Non-invasive techniques were assessed for their capabilities of detecting prosthetic valve malfunctions in 70 consecutive patients with angiographically-documented or surgically-proven prosthetic valve dysfunction. Their 74 dysfunctioning valves were studied using phonocardiography, M-mode and two-dimensional echocardiography and Doppler methods, including pulsed and continuous wave (CW) Doppler echocardiography and two-dimensional Doppler color flow mapping (2DD). These results were compared among the examinations, and also compared between 43 patients with 44 dysfunctioning mechanical valves and 27 patients with 30 dysfunctioning bioprosthetic valves. Symptoms related to valve malfunction were recognized in all patients with prosthetic valve endocarditis and in all patients but one with stenotic condition. In patients with valvular regurgitation, however, symptoms were observed in only six of the 21 patients with mechanical prostheses and in 12 of the 25 patients with bioprosthetic valves (p less than 0.01). Among 43 patients with 44 mechanical valve dysfunctions, the sensitivities of phonocardiography, M-mode and two-dimensional echocardiography and Doppler techniques were 85, 65 and 86 percent, respectively, in 20 patients with stenosis; 100, 57 and 80 percent in seven patients with transvalvular regurgitation; and 100, 50 and 100 percent in 14 patients with paravalvular regurgitation. Similarly, among 27 patients with bioprosthetic valve dysfunctions, the sensitivities of phonocardiography, M-mode and two-dimensional echocardiography and Doppler methods were 67, 100 and 100 percent, respectively, in three patients with stenotic condition; 85, 65 and 100 percent in 20 patients with transvalvular regurgitation; and 60, 40 and 100 percent in five patients with paravalvular regurgitation. Furthermore, 26 of the 27 patients with malfunctioning mechanical valves and 20 of the 24 patients with malfunctioning bioprostheses had abnormal findings using more than two techniques. In addition, each patient had at least one abnormal finding. In conclusion, malfunctioning mechanical or bioprosthetic prostheses could be detected using non-invasive techniques. The combined use of phonocardiography, M-mode and two-dimensional echocardiography and Doppler techniques is most helpful in detecting malfunctioning prostheses.

Adult↗

[Time analysis of mitral regurgitation in patients with mitral valve prolapse: a study by phonocardiography and Doppler techniques].

To assess the timing and duration of mitral regurgitation (MR) in patients with mitral valve prolapse (MVP), 20 subjects with mid-systolic click(s) and/or a late systolic murmur were studied using phonocardiography, two-dimensional echocardiography (2DE) and Doppler techniques including pulsed Doppler (PD), high pulse repetition frequency Doppler (HPRF), continuous wave Doppler (CW) and M-mode color Doppler (MD) methods and two-dimensional Doppler color flow mapping (2DD). The results were compared with those of 16 patients with a pansystolic murmur having late systolic accentuation. MVP with MR was observed in 15 of the 20 patients with mid-systolic clicks and/or a late systolic murmur and in all of the 16 patients with a pansystolic murmur. Using MD, MR signals were seen throughout systole and isovolumic relaxation period in all but one of these patients, and they were not related to the patterns of the systolic murmur. In only one, an MR signal was recorded just after the click. Five patients with a mid-systolic click lacked the findings of MVP, but two of them had MR signal only in early systole. Using PD and HPRF techniques, the timing and duration of MR signals in patients with mid-systolic clicks and/or a late systolic murmur were varied by changing the sites of the sample volume. Similarly, the timing and duration of MR signals in these patients were dependent on the ultrasonic beam direction by the CW method. In most patients with a pansystolic murmur having late systolic accentuation, however, MR signals throughout systole and the isovolumic relaxation period were demonstrated by each Doppler method. Therefore, PD, HPRF, and CW were not so efficiently sensitive or adequate techniques for investigating the timing and duration of MR, especially in patients with mid-systolic clicks and/or a late systolic murmur, who had mild or eccentric MR jets. In conclusion, 1) MR in MVP involves the entire systole and isovolumic relaxation period, 2) PD, HPRF and CW methods are not adequate for detecting mild or eccentric MR jets in patients with mid-systolic clicks and/or a late systolic murmur, and 3) MD is useful for the time analysis of MR in these patients.

Adolescent↗

[Ventricular free wall rupture following acute myocardial infarction: a two-dimensional echocardiographic assessment].

To assess the usefulness of two-dimensional echocardiography (2DE) in diagnosing ventricular free wall rupture following acute myocardial infarction, we studied the 2DE findings and the clinical pictures of seven consecutive patients with ventricular free wall rupture confirmed at the time of surgery or autopsy. Three patients had acute rupture; four, subacute rupture. All patients apparently had circulatory collapse despite continuing electrical activity at the onset of cardiac rupture. Four patients with subacute rupture recovered. In all patients, mild pericardial effusion was imaged by 2DE; however, this was not characteristic for cardiac rupture. In the patients with acute rupture, active left ventricular contractions were not observed after each QRS complex of the electrocardiogram. However, weak mitral valve motion was recorded at the time of cardiopulmonary resuscitation. The interesting and constant finding in acute rupture was the right ventricular collapse observed throughout the cardiac cycle. Diastolic right ventricular collapse was consistently observed in patients with subacute rupture, immediately after recovery from cardiogenic shock. Subacute cardiac rupture is a potentially curable lesion, and the clinical features and quick 2DE confirmation of cardiac tamponade allowed immediate surgery which saved two of the four patients.

Adult↗

[Color Doppler evaluation of a specific left ventricular flow pattern in a case of left ventricular pseudoaneurysm].

This report describes a case of left ventricular pseudoaneurysm examined by phonocardiography, two-dimensional echocardiography, Doppler color flow mapping, continuous wave and conventional pulsed Doppler echocardiography. The patient had early systolic and early diastolic murmurs. The pseudoaneurysm sac and the site of left ventricular rupture were identified by two-dimensional echocardiography. The flow between the left ventricle and the pseudoaneurysm were imaged by Doppler color flow mapping. Two jets from the left ventricle were directed toward the aneurysm during systole, and from the aneurysm toward the left ventricle in early diastole. Continuous wave Doppler and high pulse repetition frequency Doppler echocardiography demonstrated the maximum flow velocity in systole to be 3 m/sec and in early diastole, 1.7 m/sec. Those flow patterns between the left ventricle and the pseudoaneurysm could have been closely related to the murmur. Doppler echocardiography thus proved useful for detecting specific flow patterns related to a left ventricular pseudoaneurysm.

Aged↗

[A new diagnostic criteria of mitral valve prolapse syndrome].

The diagnosis of mitral valve prolapse (MVP) should depend on the presence of significant mitral regurgitation or mitral complex abnormality as far as MVP is a diseased status. Concerning the echocardiographic diagnosis, the site of prolapse is difficult to determine correctly. In this study, Doppler color flow mapping was used to detect mitral regurgitation, and to decide the site of prolapse. Our new criteria of MVP include: (1) Phonocardiographic or auscultatory findings suggestive of mitral regurgitation or mitral complex abnormality. (2) A systolic bulging or an apparent systolic ballooning of the mitral valve by two-dimensional echocardiography. (3) A mitral regurgitant signal with an acceleration flow at the site of prolapse by Doppler color flow mapping.

Echocardiography↗

Color Doppler flow mapping in cardiomyopathies and prosthetic valves.

The clinical significance of color Doppler flow mapping was assessed in patients with cardiomyopathies and prosthetic valves. Left and right ventricular obstruction and mitral regurgitation can be detected in patients with hypertrophic cardiomyopathy. Specific flow patterns in the left ventricle are clearly demonstrated in dilated cardiomyopathy. Concomitant regurgitation is easily detected in patients with dilated cardiomyopathy. The major role of this technique in patients with prosthetic valves exists in the detection of prosthetic valve regurgitation. In bioprosthetic valves, differentiation between transvalvular and paravalvular regurgitation is possible. The specific complications following the mechanical valve implantation, such as an aorto-right ventricular and aorto-left ventricular communication, can be detected using this technique. Although some problems remain, this technique is useful in the management of patients with cardiomyopathies and prosthetic valves.

Bioprosthesis↗

Value and limitations of color Doppler flow mapping in the detection and semiquantification of valvular regurgitation.

We compared color Doppler flow mapping data to angiographic data in 294 patients with suspected valvular regurgitation. Thirty-one patients had rheumatic mitral regurgitation and 37 had mitral regurgitation due to mitral valve prolapse by angiography. Ten patients had no angiographic regurgitation (4 rheumatic, 6 prolapse). The remaining patients included 86 with suspected aortic regurgitation and 130 with suspected tricuspid regurgitation. Angiographically 74 had aortic regurgitation and 111 tricuspid regurgitation. The maximum size of regurgitant jets was evaluated in each patient by color flow mapping. The width of the jets was also taken into consideration. In 29 of the 31 with rheumatic regurgitation and 67 of the 74 with aortic regurgitation by angiography, abnormal regurgitant signals were detected by color flow mapping. In both rheumatic mitral regurgitation and aortic regurgitation, color Doppler estimation of the jets correlated well with angiographic grading. The regurgitant jets in these regurgitation were not eccentric. In the 37 with mitral regurgitation in mitral valve prolapse by left ventriculography, abnormal jets were detected in 35 by color flow mapping. However, the regurgitant jets were eccentric and color Doppler estimation of the jets correlated poorly with angiographic grading. In patients with tricuspid regurgitation, color Doppler grading of regurgitation correlated poorly with right ventriculographic grading. A color Doppler underestimation was observed in 48%. In conclusion, color Doppler flow mapping is useful in the noninvasive detection and semiquantification of rheumatic mitral regurgitation and aortic regurgitation having non-eccentric jets, although this technique often underestimates the severity of regurgitation in mitral valve prolapse.

Aortic Valve Insufficiency↗