High-resolution real-time sonography (HRS) is usually performed in patients with occlusive cerebrovascular disease. Unfortunately, there is no standard imaging technique for carotid imaging. In this report, an imaging technique for detecting carotid plaques is introduced. At first, to get the most suitable image of the carotid bifurcation in the longitudinal projection, examination was carried out with a 7.5 MHz probe. The probe should maintain constant movement with the same slow speed to detect details of the plaque. The ultrasonic images were recorded with a video tape recorder simultaneously. After that, the most suitable multiple consecutive planes (5 to 7 planes) were re-photographed. Postoperatively, the detailed ultrasonographic images were reviewed and compared with the patho-morphological findings of the planes. A 57-year-old patient with an episode of amaurosis fugax was reported. He had ulcerated and calcified plaques in the left cervical carotid artery. The postoperative macro- and microscopic findings showed good correlations to the display of images at the preoperative ultrasonic examinations. The echo-density of all atheromatous plaques except for those accompanied by calcification, was lower than that of the normal media. It was very difficult to distinguish a true ulceration from a necrosis (or a bleeding space) in the arterial wall. In this case the detailed and consecutive display of the high-resolution B-mode scan was a very useful method to identify a fine structure of atheromatous plaques of the arterial wall in the cervical carotid artery.
We examined the usefulness of the three dimensional transcranial Doppler scanner (Trans-scan: TS), and compared it with the findings of carotid angiography (CAG) . The flow of Ml portion of middle cerebral artery was detectable in 9 cases out of 9 control groups (100%), 26out of 30 cases of cerebral infarction (87%) and 4 out of 4 cases of TIA (100%) . The blood flow courses and stenosis of the middle cerebral artery observed by TS agreed with those observed by CAG. The direction of the collateral blood flow was also observed by TS. But blood flow velocity could not be represented in some cases of serious cerebral arteriosclerosis which have tortuous arteries. This scanner could reproduce the angle at the time of measurement by the image and we found the reproducibility improved. TS was considered to have greater usefulness than the conventional method by transcranial Doppler.
Frequency Dependent Attenuation (FDA) measurment in liver, spleen, thyroid, and breast had been reported previously. We measured FDA of cerebrum, cerebellum and thalamus in normal brain tissue in infancy using the Spectral-Shift Zero-Crossing method. FDA values were as follows : cerebrum, 0.37±0.06dB/ cm/MHz (mean±SD) ; cerebellum, 0.52±0.14dB/cm/MHz; thalamus, 0.50±0.11dB/cm/MHz. Significant differences of FDA values were found between cerebrum and other two tissues. These data suggest FDA value shows the difference of water and lipid balance in the brain tissue. Therefore, FDA will be useful to estimate brain edema, bleeding and/or ischemia in newborns and young infants.
High echoes in both thalami have been reported only in asphyxiated neonates. We describe high echoes in both thalami in an infant with Japanese encephalitis. The patient was a 3-month old male infant. He had a high fever for 4 days and episodes of convulsions. On admission, his face was disinterested and he was stuporous. Few active movements were recognized. The anterior fontanel was tense. Neck stiffness and Kernig's sign were recognized. In the cerebrospinal fluid the white blood cells and protein were increased. The glucose was normal. After checking in to the hospitol, his general condition became better. On the 3rd day, the fever decreased and he could nurse. On the 5th day, his level of consciousness became normal. He was diagnosed as having Japanese encephalitis as indicated by an increase in the viral antibody titer. Serial brain ultrasonographic studies revealed high echoic lesions in both thalami in the acute phase, and calcification with acoustic shadows in the chronic phase. These findings were compatible with the ptahological findings in Japanese encephalitis.