Ultrasound in medicine & biology
-
Ultrasound Med Biol · Jul 1999
Comparative StudyFetal transesophageal echocardiography utilizing a 10-F, 10-MHz intravascular ultrasound catheter--comparison with conventional maternal transabdominal fetal echocardiography in sheep.
The purpose of our study in fetal sheep was to assess the measurement agreement between fetal transesophageal echocardiography (FTEE) and conventional maternal transabdominal echocardiography (CMTFE) by the Bland-Altman method. We performed our study in 11 fetal sheep between 95-103 days of gestation (term = 145 days). FTEE was performed by imaging the fetal heart in horizontal planes utilizing a 10-F, 10-MHz intravascular ultrasound catheter. ⋯ Conversely, the variability between both techniques for measuring ventricular dimensions was inadequate. We conclude that FTEE permits measurement of great vessel and cardiac valve dimensions with high agreement with CMTFE measurements. This finding strengthens the applicability of FTEE as a monitoring tool during experimental open or fetoscopic fetal cardiac interventions.
-
Ultrasound Med Biol · Mar 1999
Ultrasound of radial, ulnar, median, and sciatic nerves in healthy subjects and patients with hereditary motor and sensory neuropathies.
This study was conducted to evaluate the capability of ultrasonography to visualize extremity nerves. Fifty healthy women and men and 10 patients suffering with hereditary motor and sensory neuropathy (HMSN) were examined. The radial nerve lateral to the humerus, ulnar nerve distal to the cubital tunnel, median nerve in the middle of the forearm and proximal to the palmar crease, sciatic nerve in the middle of the thigh and tibial and common peroneal nerves just distal to their bifurcation, were investigated, employing a 7.5-MHz electronic linear-array transducer. ⋯ Thicknesses were normal in 34, increased in 11 and decreased in six of 51 nerves. In conclusion, ultrasonography allows reliable imaging of the major arm nerves and, occasionally, facilitates visualization of the sciatic, tibial and peroneal nerves in healthy subjects. Nerve size and structure did not differ significantly between patients with HMSN and healthy subjects.
-
Ultrasound Med Biol · Mar 1998
Comparative StudyDiagnosis and monitoring of middle cerebral artery occlusion with contrast-enhanced transcranial color-coded real-time sonography in patients with inadequate acoustic bone windows.
Transcranial color-coded real-time sonography (TCCS) is an emerging diagnostic technique that allows noninvasive imaging of intracranial vessels within parenchymal structures. However, in some patients, transcranial ultrasound is particularly hindered by insufficient ultrasound penetration through the temporal bone. The present study evaluates whether or not application of an echo-contrast agent in ultrasound-refractory patients with middle cerebral artery (MCA) trunk occlusion enhances image acquisition enough to yield accurate diagnoses. ⋯ In the control group, the MCA trunk could be visualized in all subjects by CE-TCCS. CE-TCCS is a sensitive and specific ultrasound method for the diagnosis of MCA trunk occlusion that overcomes the anatomical hindrance of inadequate acoustic bone window. This technique may help to identify patients suitable for thrombolytic therapies and monitor their response.
-
The first ocular echogram was published in 1956. Since then, ophthalmic ultrasound has developed into a multifaceted diagnostic discipline, the basic methods being A-scan and B-scan, Doppler techniques and recently also three-dimensional approaches. Unique for ophthalmology is the newly invented, highly resolving equipment utilising ultrasound frequencies of 50 MHz and higher, so-called ultrasound biomicroscopy. ⋯ As for orbital pathology, imaging by CT and MR appears more complete. Ultrasound is valuable, however, in particular as part of the initial clinical work-up, and for the follow-up of orbital disease. Furthermore, tissue differentiation by way of ultrasound is of great value with regard to certain entities.
-
Ultrasound Med Biol · Jan 1997
Comparative StudyLower frequency (5 MHZ) intracardiac echocardiography in a large swine model: imaging views and research applications.
Our previous investigation indicated that, in the 50-114-kg weight range, the swine model provides transeosophageal echocardiographic normal values for cardiac structures comparable to those found in human adults. Intracardiac echocardiographic imaging using a 12.5-MHz ultrasound catheter is limited, due to ultrasonic attenuation. Transesophageal echocardiographic imaging of the right heart is also limited with its anterior anatomic location. ⋯ Major intracardiac anatomic landmarks (i.e., crista terminalis, right atrial appendage, coronary sinus orifice, interatrial septum, tricuspid valve, right ventricular outflow, pulmonary veins, mitral valve and left ventricular papillary muscles) were visualized in every swine. Thus, this 5-MHz multiplane transducer, as a prototype for a steerable low-frequency intracardiac ultrasound catheter, improved both whole heart and individual cardiac structure imaging from a single intracardiac location. Further technological development and refinement is needed for routine use in research and clinical imaging practice.