Contrast technique is applied for observing blood propagation in the cardiac cavity, enhancing the Doppler signal and examining myocardial perfusion. So far, bubbles have not been able to pass through the capillaries because of their relatively large size. Progress of bubble technology has made bubbles smaller than the diameter of the pulmonary capillaries, thus allowing transpulmonic left ventricular cavity opacification . These bubbles, however, will not opacify the myocardium well because of their dissolution during flow in the blood. Not air but gas bubbles such as fluorocarbon have been found to persist for a long time in the blood, resulting in obvious myocardial opacification. Moreover, new ultrasound technology using second harmonic images is used to make the myocardial opacification clear. Intravenous myocardial contrast echocardiography is a promising tool in a clinical setting. The combination of new contrast agents and new ultrasound technology makes it possible to demonstrate perfusion images of peripheral organs such as the liver, kidney and uterus.
This study included 17 patients (5 men and 12 women) with a clinical diagnosis of moyamoya disease from conventional angiograms. Bilateral basal arteries were measured by the transtemporal approach with a 2-MHz pulsed Doppler instrument (TC-2 64B, EME) . Reliable TCD recordings were obtained in 28 out of 34 basal arteries (82.4%) . These TCD findings were classified into three patterns : 1) high-high pattern; the mean cerebral blood flow velocity (CBFV) was increased throughout the basal arteries by over 70 cm/s (7 arteries, 25.0%), 2) high-low pattern ; the mean CBFV was fastest (over 70 cm/s) at the ICA or proximal MCA, and the mean CBFV was markedly decreased distally (15 arteries, 53.6%), and 3) low-low pattern; the mean CBFV was less than 40 cm/s throughout the basal arteries (4 arteries, 15.4%) . The high-high pattern on TCD was seen predominantly in younger patients and those in the earlier stages of the disease. The high-low pattern was the most common one of CBFV as assessed by TCD in moyamoya patients. The low-low pattern on TCD was more common in the later stages following angiographic evaluation by Suzuki's criteria. The above patterns based on TCD findings show good correlation with the age of the patient and the clinical diagnosis at onset. TCD appears to be very useful for evaluation of patients with moyamoya disease.
We evaluated the efficacy of superficial temporal to middle cerebral artery (STA-MCA) bypass based on data obtained from Doppler sonography (DS) of the ophthalmic artery (OA) . [Materials and methods] Thirty-three cases of internal carotid artery (ICA) occlusion were examined. DS examination was performed before surgery, at 1 month after bypass, and during the follow-up period. [Results] 1) The abnormal DS findings were divided into two patterns : a stenosis pattern (SP; 9 cases) and a reversed flow pattern (RP; 24 cases) . 2) DS of the OA at 1 month after bypass among RP cases showed normograde flow in 2 cases and a decrease of reversed flow in 16. During the follow-up period, improvement of reversed flow (including normograde flow) could be seen in most of the patients who had RP preoperatively. 3) Angiographic findings in the ophthalmic artery were well correlated with the DS finding in the OA, not only in the preoperative, but also in the postoperative stage. [Conclusion] DS of the OA can be used to evaluate the effectiveness of STA-MCA bypass by comparing the OA findings before and after bypass. STA-MCA bypass brings about an improvement in retrograde OA flow.
We studied the pre- and postoperative single photon emission CT (SPECT) and TCD findings in nine patients who underwent endarterectomy (CEA) . Mean flow velocities in the middle cerebral artery (MCA - FVs) as well as postoperative cerebral blood flow (CBF) on SPECT were increased in six of these patients. The preoperative MCA - FVs of these six patients were less than these of controls. However, in the other three patients, whose pre-operative MCA-FVs were greater than those of the controls, postoperative CBF findings on SPECT failed to improve. Pre- and postoperative pulsatility index (PI) had no correlation with changes in cerebral blood flow (CBF) imaging on SPECT.
Ultrasonography was applied to 37 carotid arteries with occlusive lesions prior to carotid surgery. The relationship between plaque echogenicity and histological features of the carotid plaque, especially the presence or absence of hemorrhage, and between the plaque histology and clinical symptoms were examined retrospectively. The echogenicity of the plaque was divided into three grades, hypoechoic, isoechoic and hyperechoic, according to the degree of echogenicity compared to that of the intimal layer. Among the 37 carotid arteries, 9 were hypoechoic, 9 were isoechoic and 19 were hyperechoic. Plaque hemorrhage (PH) was found in 7 of the 9 hypoechoic, 2 of the 9 isoechoic and in none of the 19 hyperechoic plaques. Most of the cases of hypoechoic plaques were associated with hemorrhage. Neurological symptoms were found in 7 of 9 patients with PH and in 11 of 28 patients without PH. Plaque hemorrhage was found significantly more frequently in symptomatic lesions. It is considered possible to estimate PH by the echogenicity of the plaque and that PH plays an important role in the occurrence of clinical symptoms. In conclusion, ultrasonography, because of its potential for detecting plaque hemorrhage, is presented as one of the most important preoperative examination techniques in patients with occlusive carotid artery disease.
A 52-year-old man presented with a pontine abscess manifesting as diplopia and right hemiparesis initially misdiagnosed as a brain stem glioma. His condition worsened rapidly. Magnetic resonance (MR) imaging revealed a rapidly growing mass lesion in the pons. At first the patient was treated with antibiotics, but his consciousness deteriorated. The abscess was resolved after ultrasound-guided aspiration via a suboccipital approach and appropriate antibiotic therapy. We believe that this is the first report of a favorable outcome in a patient with a brain stem abscess treated by ultrasound- guided aspiration. The value of ultrasound-guided aspiration with color Doppler is explained with a review of the relevant literature.
Intravascular ultrasound sonography was employed in a patient with traumatic dissection of the cervical internal carotid artery (ICA) . A 21-year-old male presented with right hemiparesis and motor aphasia 36 days after a motorcycle accident. CT and MR imaging showed an infarction in the left middle cerebral artery area. Cerebral angiograms showed dissection and pseudoaneurysm in the left cervical ICA. Intravascular ultrasound images demonstrated multiple dissections of the ICA beginning at the C2 vertebral level up to the carotid canal. The extent of the dissection was larger than that shown by angiography. The minimum diameter of the true lumen was 3.0 mm. Balloon expansion to deliver short stents carried a high risk of distal embolism, and the diameter of the true lumen was not large enough to allow placement of a long stent. As a result, ligation of the proximal ICA combined with anastomosis of the superficial temporal artery to the middle cerebral artery was chosen as the treatment. Intravascular ultrasound imaging was useful for evaluating the morphology of the dissection and the true lumen in the cervical ICA and for selecting an appropriate treatment.