Recently, the technique of harmonic contrast imaging has been developed which exploits the nonlinear properties of ultrasound contrast agents by processing the second harmonic echo signal of the transmitted ultrasound pulse. The contrast agent employed is Levovist (Schering), which was released in Japan in 1999. The advantage of harmonic imaging is its selective imaging of differences between tissue and blood perfusion areas.
The purpose of the present study was to investigate a method of detecting human brain perfusion by ultrasound with second harmonic signals and contrast agents in eight patients with brain tumors. We used pulse inversion harmonic imaging, which is the latest technique for visualizing ultrasound contrast agents, thereby allowing us to image brain perfusion, and well enhanced perfusion images were obtained in all cases.We performed analysis resulting in wash-in wash-out curves, and concluded that this method could be used for diagnosis of brain hemodynamics.

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While the head-up tilt test (HUT) is useful for establishing a diagnosis of neurally mediated syncope (NMS), it exposes patients to the stress of syncopal or presyncopal attacks unnecessarily. In order to find any changes that might predict the manifestation of syncopal attacks, we carried out transcranial Doppler sonography (TCD) during HUT in four patients with syncope. Changes in heart rate (HR), blood pressure (BP), mean blood flow velocity (MFV) in the middle cerebral artery and pulsatility index (PI) were estimated during the whole HUT period. HUT was positive in two patients and negative in the other two. In the two patients with positive HUT, MFV declined gradually from the beginning of HUT, showing a marked drop at the time of presyncopal symptoms. PI also increased gradually for 10 min prior to syncope and showed marked elevation at the time of syncope. After treatment, the time to syncope was prolonged, and the severity and frequency of NMS were reduced in both patients. The slopes of MFV decline and PI elevation during HUT were also reduced after treatment. The gradual MFV decline associated with gradual PI elevation may reflect the dysfunction of the cerebrovascular autonomic nervous control system which may underlie the pathogenesis of NMS. The estimation of gradual changes in MVF and PI during HUT may make it possible to predict the manifestation of syncopal or presyncopal attacks. TCD monitoring during HUT may therefore be useful for predicting syncopal attacks and protecting patients from unnecessary stress.

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A method was developed to create microbubbles efficiently by adding one drop of Horizon^® to cold, agitated saline (one-drop method, or ODM) . We evaluated whether the ODM would improve the detection rate of high-intensity transient signals (HITS) in patients with intracardiac right-to-left shunts (RL-S) .
The subjects for the study were 98 patients who underwent transcranial color flow imaging (TC-CFI) between November 1999 and May 2000. These included 46 patients whose RL-S had been confirmed by transesophageal echocardiography. The detection rate of HITS on the bilateral middle cerebral arteries and/or basilar artery using TC-CFI with ODM was compared with that without ODM.
HITS were found in 17 (17.4%) of the 98 patients using TC-CFI without ODM. On the other hand, 25 patients (25.5%) were found to have HITS using TC-CFI with ODM. Among patients documented as having RL-S (47.8%), the ratio of HITS-positive patients was significantly higher when three arteries were examined under ODM than with single-artery examination (73.3% vs.35.5%) .
ODM is a simple and useful method for improving the detection rate of HITS in patients with RL-S.

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We report a 70-year-old man with bilateral occlusion of the carotid bifurcation, diagnosed by preoperative carotid ultrasonography. He was admitted for surgical treatment of a giant thoracic aortic aneurysm, and had a history of frequent TIAs and right hemiparesis. Contrast-enhanced 3D-MR angiography and conventional angiography confirmed bilateral occlusion of the carotid bifurcations. Since such a condition is very rare, we discuss the diagnostic value of carotid ultrasonography and its clinical significance.

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Carotid atherosclerosis is known to be a useful indicator of ischemic cerebrovascular disease and ischemic heart disease. Noninvasive ultrasonic assessment is a standard method for screening of carotid artery disease. This report is to certify the consensus in Japan for evaluating carotid atherosclerosis by ultrasonography.
The ultrasonic device employed needs to have a linear array transducer of over 5 MHz and/or similar ultrasonic ability. A Doppler subunit is a useful optional tool for evaluating blood flow velocity, which is an important parameter for assessing severe vascular lesions. Complete ultrasonic evaluation of the carotid artery tree must be done from the common carotid artery and carotid bulb to the internal carotid artery. Among several parameters, we selected the maximum intima-media thickness (max-IMT) of the whole carotid artery as the most valuable for assessing carotid atherosclerosis. Max-IMT on the far wall of the common carotid artery is a stable and essential item. In this report, max-IMT indicates the maximum wall thickness including the plaque lesion. Plaque score and mean IMT are optional authorized parameters of carotid atherosclerosis. Percentage area reduction is a standard ultrasonic measurement method for stenosis. Lesion echogenicity is expressed as hypo-, iso or hyperechoic. Medical management will depend on the severity of carotid atherosclerosis evaluated by ultrasonography.

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