Ultrasound has several advantages over CT or MRI, such as real-time data acquisition, mobility, cost-efficiency, and freedom from the risk of X-ray radiation injury and problems with the use of magnetic materials. Recent advances in ultrasonography, such as transcranial color-coded duplex imaging, broad bandwidth scanning, 3-dimensional ultrasound and ultrasonic contrast medium, have enabled the development of new methods of clinical diagnosis. The diagnostic usefulness of ultrasonography is described as a tool for neuronavigation where intraoperative findings must be displayed in real time. Ultrasonography will help surgeons to make appropriate judgements regarding surgical procedures in relation to intraoperative shift of the brain, especially in cases of cystic lesion, ventricular or multiple lesions, which tend to be responsible for large brain shifts. Ultrasound will provide anatomical findings over the course of surgery and make up for the deficits of other diagnostic tools such as MRI. Ultrasound-based neuronavigation will thus become popularized. The role of neurosonology in 21st century medicine is thus discussed by reference to neuronavigation as an example.
Ocular ischemic syndrome can be of either the acute type (amaurosis fugax, retinal artery occlusion and ischemic optic neuropathy) or the chronic type (venous stasis retinopathy and ischemic oculopathy). We carried out etiological studies on 35patients (19men, 16women, aged 62±16years) with retinal artery occlusion and 21patients (13men, 8women, aged 47±19 years) with amaurosis fugax. In all patients, carotid ultrasonography was performed to clarify the extent of carotid artery disease ipsilateral to the retinal artery occlusion and amaurosis fugax. All the patients underwent electrocardiography and transesophageal echocardiography. Arterial stenosis exceeding 50% of the diameter of the internal carotid artery ipsilateral to the symptomatic eye was more frequent in patients with retinal artery occlusion than in those with amaurosis fugax. Patent foramen ovale more frequent in the latter than in the former. Patients with venous stasis retinopathy and ischemic oculopathy (neovascular glaucoma) had occlusion of the ipsilateral carotid artery with reversed ophthalmic artery or severe stenosis of the ipilateral carotid artery with stenosis of the ipsilateral ophthalmic artery. Neurosonologic studies can provide valuable clinical data on ocular ischemic syndrome.
We investigated details of contrast TCD examination for detecting right-to-left shunts (RLS) in relation to respiratory maneuvers, especially the timing of a Valsalva maneuver (VM). We analyzed 14 patients with PFO proved by TEE. All underwent TCD (Multi-Dop X4-DWL) monitoring of the bilateral MCA. The following protocol with injections of 10mL of either agitated saline (PS)or agitated saline with one drop of Horizon® (ODM) as echo contrast; RM1: no VM, RM2: echo contrast injection during VM for 8seconds, RM3: VM for 5 seconds starting at the beginning of echo contrast injection, RM4: VM for 5 seconds 5 starting 5seconds after the beginning of echo contrast injection, RM5: VM for 5seconds starting 10seconds after the beginning of echo contrast injection, RM6: repetitive coughing between 2 and 13 seconds after the beginning of echo contrast injection. We counted contrast microembolic signals (cMES) for 60 seconds after the injection, and judged RLS to be positive if more than one cMES were detected. RM4 and RM5 with ODM, which demonstrated 12 cases to be RLS-positive, were the most sensitive maneuvers. Whichever test was used with PS, RLS was undetectable in no more than 8 cases. TCD with PS is an inadequate method for identifying RLS. The VM should be performed after the beginning of contrast injection.
Background and Objective: In transcranial color flow imaging, stability of the probe is a critical concern for the quality of recordings. We carried out TC-CFI monitoring with a new 6-axis probe holder to improve the consistency of the recording. Subjects and Methods: Three normal subjects and two patients with acute stroke underwent TC-CFI studies with the newly devised probe holder. The holder, fixed to the examinee's temple, supported the sonoprobe with three pairs of ball joints, which enabled it to move around 6 axes-namely X, Y, Z, yaw, pitch, and roll-independently. The examiner was allowed to designate and fix the probe at any position that yielded the best image via the temporal window. TC-CFI recording was continued for more than 10 min. During the recording, the examiner did not support or relocate the probe, and the examinees were asked to rise from a supine to a sitting position. Results: Serial recordings showed no significant change in imaging section, blood flow profile, or signal intensity throughout the measurement. Conclusions: The probe holder with 6-axis movement contributed to the consistency of TC-CFI recording, and may facilitate dynamic evaluation of blood flow in the brain.
The present study was conducted to evaluate the applicability of transcranial color-coded sonography (TCCS) for detection of hemispheric hyperperfusion syndrome after carotid endarterectomy (CEA). This prospective study included 125 consecutive patients who underwent CEA for severe carotid stenosis. TCCS studies were performed serially to evaluate MCA flow velocity before and after CEA. The regional CBF in the MCA territory was evaluated quantitatively before, and 4 and 14 days after CEA using single photon emission computed tomography (SPECT). By TCCS, we detected MCA in 112 (90%) of the 125 patients. Fourteen (13%) of them showed clinical symptoms of hyperperfusion syndrome after CEA. In patients with hyperperfusion syndrome, the affected MCA mean flow velocity ratio (after CEA/before CEA) was higher than that in patients without hyperperfusion (2.14 ±0.45 vs 1.26 ±0.26 times, p<0.001). All 14 patients with hyperperfusion syndrome had a marked change (≥1.5 times) in MCA mean flow velocity at any time point 1 to 4 days after CEA. The ratio of affected MCA mean flow velocity before CEA compared with that 4 days after CEA was significantly correlated with that for rCBF (R=0.44, p<0.0001). TCCS with echo contrast agents is applicable for evaluation of hyperperfusion syndrome after CEA.
High-intensity transient signals (HITS) revealed by transcranial Doppler (TCD) can be used to detect microthrombi as indicators of cerebral infarction. We postulated that HITS could also be used to detect bacterial clumps in the blood of patients with cardiovascular infection. We measured inflammatory reactions in laboratory tests and recorded TCD in the middle cerebral artery (MCA) and internal carotid artery (IC) continuously for 30 min in patients with pacemaker lead infection and infectious endocarditis. HITS was detected in two cases, and these decreased concomitantly with reduction of the inflammatory reaction. HITS revealed by TCD can detect emboli more than 10 μm in diameter. As bacterial clumps measure 0.3-30 μm, the signals represented as HITS may have been microemboli or bacterial clumps. Because they decreased with improvement of the inflammatory reaction, HITS may be useful not only clinically but also for monitoring of pathological status.