BACKGROUND: The cerebral blood flow velocity (CBFV) and rate pressure product (RPP) have been reported to benefit hemodynamics more during exercise in the recumbent position than during that in the upright position. However, it is unclear which angle is of the greatest benefit to hemodynamics during exercise in the recumbent position. This study aimed to evaluate the effect of the recumbent angle on CBFV and RPP during exercise. METHODS: In a balanced crossover study, 15 healthy volunteers (age, 18.7±1.1 years) were asked to perform the bicycle exercise four times in the upright and at recumbent angles of 67° (R), 47°R, and 15°R, with weekly intervals between each condition. The exercise intensity was set initially at 50 W and increased by 25 W every 2 minutes up to 150 W. CBFV in the middle cerebral artery (MCA) was measured using transcranial doppler sonography. All data were analyzed using two-way repeated-measures analysis of variance. RESULTS: CBFV at 15°R was significantly higher than that in the upright position and at 67°R at 10 minutes recovery (69±16 vs. 56±7 and 58±10 cm/s, respectively; P<0.05). The RPP was significantly lower at 67°R, 47°R, and 15°R than in the upright position immediately after exercise (176±23, 177±22, and 173±26, respectively, vs. 241±42 mmHg×beats/min×10⁻²; P<0.001). CONCLUSIONS: At an angle of less than 67°R, exercise increases CBFV and reduces RPP, relative to those during exercise in the upright position. This hemodynamic effect was most prominent at 15°R, where cerebral circulation was further increased in the recovery phase.
Cerebrovascular Circulation ; Cross-Over Studies ; Healthy Volunteers ; Hemodynamics ; Middle Cerebral Artery ; Posture ; Ultrasonography, Doppler, Transcranial

PURPOSE: To evaluate the efficacy and safety of cerebral monitoring by transcranial Doppler ultrasonography (TCD) for the detection of cerebral ischemia during carotid endarterectomy (CEA). METHODS: From August 2004 to December 2013, 159 CEAs were performed in a tertiary hospital. All procedures were performed under general anesthesia. Intraoperative TCD was routinely used to detect cerebral ischemia. Of the 159 patients, 102 patients were included in this study, excluding 27 patients who had a poor transtemporal isonation window and 30 patients who used additional cerebral monitoring systems such as electroencephalography or somatosensory evoked potentials. When mean flow velocity in the ipsilateral middle cerebral artery decreased by >50% versus baseline during carotid clamping carotid shunting was selectively performed. The carotid shunt rate and incidence of perioperative (<30 days) stroke or death were investigated by reviewing medical records. RESULTS: Carotid shunting was performed in 31 of the 102 patients (30%). Perioperative stroke occurred in 2 patients (2%); a minor ischemic stroke caused by embolism in one and an intracerebral hemorrhage in the other. Perioperative death developed in the latter patient. CONCLUSION: TCD is a safe cerebral monitoring tool to detect cerebral ischemia during CEA. It can reduce use of carotid shunt.
Anesthesia, General ; Brain Ischemia ; Cerebral Hemorrhage ; Constriction ; Electroencephalography ; Embolism ; Endarterectomy, Carotid* ; Evoked Potentials, Somatosensory ; Humans ; Incidence ; Medical Records ; Middle Cerebral Artery ; Stroke ; Tertiary Care Centers ; Ultrasonography, Doppler, Transcranial*

PURPOSE: We report the case of a patient diagnosed with central retinal artery occlusion caused by cardiac myxoma who underwent surgery to remove the myxoma. CASE SUMMARY: A 47-year-old woman came to our clinic presenting with a sudden decrease of visual acuity in the left eye. At the first visit, left eye visual acuity was hand motion, and intraocular pressure was 15.4 mmHg. A relative afferent pupillary defect was observed in the left eye. On fundus examination, a pale retina and cherry-red spot were observed at the posterior pole. On optical coherence tomography, macular edema was found. On fluorescein angiography and indocyanine green angiography, delayed blood circulation of the retina and choroid was found at early and late stages. Cerebral angiography was performed in the neurosurgery department and showed no occlusion of the ophthalmic artery. Cardiac ultrasonography and brain magnetic resonance imaging were performed. On cardiac ultrasonography, 4.46 × 2.09 cm cardiac myxoma was found. Resection of the cardiac myxoma was conducted in the thoracic and cardiovascular surgery department. Multiple cerebral infarcts were detected by brain imaging, and antithrombotic treatment was administered. After one month, blood circulation in the retina and choroid was observed in fluorescence angiography, but there was no improvement of visual acuity. At the 3-month follow-up visit, macular edema was decreased, but retinal atrophy and epiretinal membrane were observed on optical coherence tomography. CONCLUSIONS: Central retinal artery occlusion is a disease related to one's general condition. We experienced this case of central retinal artery occlusion caused by cardiac myxoma.
Angiography ; Atrophy ; Blood Circulation ; Brain ; Cerebral Angiography ; Choroid ; Epiretinal Membrane ; Female ; Fluorescein Angiography ; Follow-Up Studies ; Hand ; Humans ; Indocyanine Green ; Intraocular Pressure ; Macular Edema ; Magnetic Resonance Imaging ; Middle Aged ; Myxoma* ; Neuroimaging ; Neurosurgery ; Ophthalmic Artery ; Pupil Disorders ; Retina ; Retinal Artery Occlusion* ; Retinal Artery* ; Retinaldehyde ; Tomography, Optical Coherence ; Ultrasonography ; Visual Acuity

An 8-month old female presented with spontaneous subarachnoid hemorrhage and was treated successfully with endovascular coil embolization of the ruptured aneurysm. Transcranial Doppler ultrasound performed four days later demonstrated middle cerebral artery (MCA) velocities greater than 350 cm/sec on the right and greater than 200 cm/sec on the left, despite medical management. The patient demonstrated no focal neurological deficits, though examination was limited by our patient's sedation and intubation. Angiography revealed severe vasospasm of the supraclinoid internal carotid and MCA territories, bilaterally. The vasospasm was refractory to the administration of intra-arterial verapamil. Balloon angioplasty was attempted, but the device could not be advanced safely due to the small size of the patient's vessels and the stiffness of the device. A microcatheter (0.0165" diameter) was advanced over a J-shaped soft microwire (0.014" diameter) to perform mechanical angioplasty in the internal carotid artery and MCA vessels bilaterally. Dramatic improvement was seen angiographically and on transcranial Doppler, and no complications were seen.
Aneurysm ; Aneurysm, Ruptured ; Angiography ; Angioplasty ; Angioplasty, Balloon ; Carotid Artery, Internal ; Embolization, Therapeutic ; Female ; Humans ; Infant* ; Intubation ; Middle Cerebral Artery ; Subarachnoid Hemorrhage ; Ultrasonography ; Vasospasm, Intracranial* ; Verapamil

PURPOSE: Lacunar stroke, in the context of small vessel disease, is a type of cerebral infarction caused by occlusion of a penetrating artery. Pulsatility index (PI) is an easily measurable parameter in Transcranial Doppler ultrasound (TCD) study. PI reflects distal cerebral vascular resistance and has been interpreted as a surrogate marker of small vessel disease. We hypothesized that an increased PI, a marker of small vessel disease, might be associated with a larger infarct volume in acute lacunar stroke. MATERIALS AND METHODS: This study included 64 patients with acute lacunar stroke who underwent TCD and brain MRI. We evaluated the association between the mean PI value of bilateral middle cerebral arteries and infarct volume on diffusion-weighted MRI using univariate and multivariate linear regression. RESULTS: The mean infarct volume and PI were 482.18±406.40 mm3 and 0.86±0.18, respectively. On univariate linear regression, there was a significant positive association between PI and infarct volume (p=0.001). In the multivariate model, a single standard deviation increase of PI (per 0.18) was associated with an increase of 139.05 mm3 in infarct volume (95% confidence interval, 21.25 to 256.85; p=0.022). CONCLUSION: We demonstrated that PI was an independent determinant of infarct volume in acute lacunar stroke. The PI value measured in acute stroke may be a surrogate marker of the extent of ischemic injury.
Aged ; Cerebral Infarction/*diagnostic imaging/*physiopathology ; *Diffusion Magnetic Resonance Imaging ; Female ; Humans ; Linear Models ; Male ; Middle Aged ; Middle Cerebral Artery ; Pulsatile Flow/physiology ; Retrospective Studies ; Stroke, Lacunar/*diagnostic imaging/*physiopathology ; *Ultrasonography, Doppler, Transcranial ; Vascular Resistance/physiology

OBJECTIVETo explore the pattern of variations in middle cerebral artery peak systolic velocity (MCA PSV) and cardiothoracic ratio (CTR) during early pregnancy, establish their reference ranges and explore their correlation with the crown-rump length (CRL).

METHODSA total of 522 pregnant women with normal findings in antenatal examinations underwent routine color Doppler ultrasound examination to collect the data of MCA PSV, CTR and CRL. The reference ranges of MCA PSV and CTR for different CRL levels were established, and the correlation of MCA PSV and CTR with CRL was analyzed.

RESULTSDuring the first trimester, MCA PSV and CRL showed a moderate positive correlation with a correlation coefficient of 0.426 (P<0.001), while CTR and CRL showed no significant correlation (0.168, P<0.001). The reference range of MCA PSV was 14.35 (14.08-14.62) cm/s and that of CTR was 0.34 (0.33-0.34) during early pregnancy.

CONCLUSIONColor Doppler ultrasound is a safe and feasible modality to assess fetal MCA PSV and CTR for detecting fetal growth abnormalities in early pregnancy. The established reference ranges of MCA PSV and CTR offer a clinical theoretical basis for detecting α-thalassemia in early pregnancy.

Blood Flow Velocity ; Crown-Rump Length ; Female ; Fetal Diseases ; diagnostic imaging ; Humans ; Middle Cerebral Artery ; physiology ; Pregnancy ; Pregnancy Trimester, First ; Reference Values ; Systole ; Ultrasonography, Doppler, Color ; Ultrasonography, Prenatal

No abstract available.
*Aorta, Thoracic/ultrasonography ; Aortic Diseases/*complications/diagnosis ; Catheterization, Peripheral/*adverse effects ; Cerebral Angiography/*adverse effects ; Electrocardiography ; Fatal Outcome ; *Femoral Artery ; Heart Arrest/diagnosis/etiology ; Humans ; Male ; Middle Aged ; Myocardial Infarction/diagnosis/*etiology ; Punctures ; *Sinus of Valsalva/ultrasonography ; Thrombosis/diagnosis/*etiology

BACKGROUND: Doppler velocimetry studies of placental and fetal circulation can provide important information regarding fetal well­being providing an opportunity to improve fetal outcome. The present study was undertaken to evaluate the role of middle cerebral to umbilical artery pulsatility index ratio (MCA/UA PI Ratio) as a predictor of perinatal outcome in hypertensive pregnant patients admitted from January 2009- December 2011 at the De La Salle-University Medical Center
OBJECTIVES: To correlate the neonatal outcomes of hypertensive pregnant women at 28-34 weeks AOG with the middle cerebral artery and umbilical artery pulsalitility index ratio.
STUDY DESIGN: A retrospective cohort was done on records of patients with hypertension who delivered from January 2009 - Decem­ber 2011. Doppler ultrasound results of said patients that were available at the OB-GYN ultrasound section were recorded and the MCA/UA PI Ratio computed. Doppler results were then compared to neonatal outcomes
RESULTS: Results of the study shows that 10 out of the 17 hypertensive patients with decreased MCA/UA PI Ratio developed Intrau­terine growth restriction. 62.5% of those patients who had normal MCA/UA PI Ratio results delivered term, while 87.5% of those who had decreased MCA/UA PI Ratio delivered preterm (P <0.002). However results of the MCA/UA PI ratio has no association on APGAR scores at 1 and 3 minutes.
CONCLUSION: Decreased MCA/UA PI Ratio results have an association on the development of adverse neonatal outcomes in hyper­tensive pregnant women.

 

 

Human ; Male ; Female ; Pregnancy ; Umbilical Arteries ; Middle Cerebral Artery ; Ultrasonography, Prenatal ; Fetus ; Placenta ; Hypertension ; Ultrasonography, Doppler

BACKGROUND: The demographics of the stroke population consist mainly of elderly patients. Transcranial Doppler is an effective method for intracranial flow detection, but can be limited due to the poor temporal window (PTW), which is frequent in the elderly. Therefore, we investigated whether the low frequency 1.6-MHz probe can be useful to improve flow detection for PTW. METHODS: All 201 participants had a history of transient ischemic attack or minor ischemic stroke. Firstly, we analyzed the success rate of recording intracranial blood flow via temporal window by using 2.0-MHz (high frequency, HF) and 1.6-MHz (low frequency, LF) probes for a maximum of 10 minutes. Secondly, mean flow velocity (MFV) and pulsatile index (PI) of insonated spectrum of 25 patients with good temporal window were compared between the two probes. RESULTS: Seventy-eight patients were female and the mean age was 64.1+/-12.4 years. Among 402 windows, 125 (31.1%) were undetected when using the 2.0-MHz probe. Fifty-five patients were detected for the spectrum by the 1.6-MHz probe. However, 70 (17.4%) still remained as PTW. Between the two probes, there were no significant differences of variables from the middle cerebral arteries: MFVs (HF 61.0+/-14.1 vs. LF 61.3+/-14.8 cm/sec, p=0.403 in the right; HF 59.6+/-13.4 vs. LF 59.3+/-13.3 cm/sec, p=0.232 in the left) and PIs (HF 0.82+/-0.17 vs. LF 0.82+/-0.18, p=0.929 in the right; HF 0.82+/-0.20 vs. LF 0.83+/-0.17, p=0.605 in the left). CONCLUSIONS: Conventional 2.0-MHz probe had relatively high proportion of PTW but 1.6-MHz probe was feasible to improve flow detection for PTW.
Aged ; Cerebral Arteries ; Demography ; Female ; Humans ; Ischemic Attack, Transient ; Middle Cerebral Artery ; Stroke ; Temporal Bone ; Ultrasonography, Doppler, Transcranial

OBJECTIVETo evaluate the hemodynamic changes in the central branches of the middle cerebral artery in different stages of neonatal hypoxic-ischemic encephalopathy (HIE) and provide new evidence for clinical diagnosis of HIE.

METHODSFrom March, 2013 to July, 2013, a total of 136 newborn infants were diagnosed to have HIE in our center. We performed two-dimensional ultrasonography and color Doppler ultrasound for assessments of systolic velocity (Vs) and resistant index (RI) of the central branches of the middle cerebral artery. The data were compared with the results of a control group consisting of 251 normal full-term infants.

RESULTSInfants with mild HIE showed hyperechoic changes in the white matter around the ventricle, while in moderate and severe HIE, such hyperechoic changes were diffuse in both hemispheres with unclear echoes of the brain structures. Pulse Doppler assessments of hemodynamics of the central branches of the middle cerebral artery demonstrated a significant decrease in Vs and an increase in RI regardless of HIE severity (P<0.05). In addition, Vs and RI values in mild HIE infants differed significantly (P<0.05) from those in infants with moderate and severe HIE, who had comparable Vs and RI values (P>0.05).

CONCLUSIONTranscranial ultrasonography may provide dynamic information on cerebral blood flow in neonates and hemodynamic parameters of the central branches of the middle cerebral artery are valuable for clinical diagnosis and early intervention of HIE.

Brain ; blood supply ; Cerebrovascular Circulation ; Hemodynamics ; Humans ; Hypoxia-Ischemia, Brain ; diagnostic imaging ; Infant ; Infant, Newborn ; Middle Cerebral Artery ; diagnostic imaging ; Ultrasonography