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Microvascular blood flow velocities measured with a retinal function imager: inter-eye correlations in healthy controls and an exploration in multiple sclerosis
摘要： Background: The retinal microcirculation has been studied in various diseases including multiple sclerosis (MS). However, inter-eye correlations and potential differences of the retinal blood flow velocity (BFV) remain largely unstudied but may be important in guiding eye selection as well as the design and interpretation of studies assessing or utilizing retinal BFV. The primary aim of this study was to determine inter-eye correlations in BFVs in healthy controls (HCs). Since prior studies raise the possibility of reduced BFV in MS eyes, a secondary aim was to compare retinal BFVs between MS eyes, grouped based on optic neuritis (ON) history and HC eyes. Methods: Macular arteriole and venule BFVs were determined using a retinal function imager (RFI) in both eyes of 20 HCs. One eye from a total of 38 MS patients comprising 13 eyes with ON (MSON) and 25 eyes without ON (MSNON) history were similarly imaged with RFI. Results: OD (right) and OS (left) BFVs were not significantly different in arterioles (OD: 3.95 ± 0.59 mm/s; OS: 4.08 ± 0.60 mm/s, P = 0.10) or venules (OD: 3.11 ± 0.46 mm/s; OS: 3.23 ± 0.52 mm/s, P = 0.06) in HCs. Very strong inter-eye correlations were also found between arteriolar (r = 0.84, P < 0.001) and venular (r = 0.87, P < 0.001) BFVs in HCs. Arteriolar (3.48 ± 0.88 mm/s) and venular (2.75 ± 0.53 mm/s) BFVs in MSNON eyes were significantly lower than in HC eyes (P = 0.009 and P = 0.005, respectively). Similarly, arteriolar (3.59 ± 0.69 mm/s) and venular (2.80 ± 0.45 mm/s) BFVs in MSON eyes were also significantly lower than in HC eyes (P = 0.046 and P = 0.048, respectively). Arteriolar and venular BFVs in MSON and MSNON eyes did not differ from each other (P = 0.42 and P = 0.48, respectively). Conclusions: Inter-eye arteriolar and venular BFVs do not differ significantly in HCs and are strongly correlated. Our findings support prior observations that arteriolar and venular BFVs may be reduced in MS eyes. Moreover, this seems to be the case in both MS eyes with and without a history of ON, raising the possibility of global blood flow alterations in MS. Future larger studies are needed to assess differences in BFVs between MSON and MSNON eyes.
关键词： Blood flow velocity,Neurology,Multiple sclerosis,Optic neuropathy,Inter-eye correlation,Retinal function imager
更新于2025-09-11 14:15:04
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Blood Flow in Monocular Retinoblastoma Assessed by Color Doppler and Correlations With High-Risk Pathologic Features
摘要： PURPOSE. To use color Doppler to analyze blood ?ow in the retrobulbar central retinal artery (CRA) and central retinal vein (CRV) in monocular retinoblastoma. METHODS. This prospective study included patients with group D and E retinoblastomas managed with only enucleation. Peak blood velocities were assessed in the CRA and CRV of tumor-containing eyes (CRAv and CRVv, respectively). The resistivity index in the CRA (RIa) and pulse index in the CRV (PIv) were calculated and related to optic nerve invasion (ONi), choroid invasion (mCHi), and tumor volume. RIa and PIv were also calculated for healthy eyes. RESULTS. In total, 25 patients with a mean age of 30.8-months old were included. The means (SD) for CRAv, CRVv, RIa, and PIv were 26.94 (12.32) cm/s, 16.2 (9.56) cm/s, 0.88 (0.12) and 0.79 (0.29), respectively. Tumor volume was signi?cantly correlated with CRAv (P ? 0.025) and RIa (P ? 0.032). ONi was present in 19 eyes and correlated with a smaller PIv (P < 0.001). A PIv less than 0.935 had a sensitivity of 89.5% and speci?city of 83.3% for predicting ONi. mCHi was not correlated with ?ow values. Healthy eyes had a signi?cantly lower RIa (P < 0.001) and lower PIv than eyes with (P ? 0.009) and without (P < 0.001) ONi. tumor volume was directly CONCLUSIONS. correlated with CRAv and RIa, and lower PIv was correlated with optic nerve invasion when a predictive cut-off value of less than 0.935 was applied. Comparisons with healthy eyes showed that tumor-containing eyes were associated with higher RIa and PIv values.
关键词： histopathology,eye enucleation,blood flow velocity,retinoblastoma,color doppler ultrasonography
更新于2025-09-09 09:28:46
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[ACM Press the 3rd International Conference - Seoul, Republic of Korea (2018.08.22-2018.08.24)] Proceedings of the 3rd International Conference on Biomedical Signal and Image Processing - ICBIP '18 - Correction of Aliasing in Color Doppler Echocardiography Based on Image Processing Technique in Echodynamography
摘要： A study about the program of color Doppler to improve blood velocity estimation has been developed. Color Doppler echocardiographic images were acquired using Philips IE33 have a crucial issue the ambiguity of the offset beams when the correct velocity of the blood flow exceeds the velocity of the Nyquist limit. Therefore, velocity dealiasing is needed in quality control of color Doppler echocardiographic data to correct velocities using EDG (echodynamography) based on observer and machine interaction. The program is applied to echocardiography images of aortic stenosis subject as a technique to assess cardiovascular function. One challenging with color Doppler is correcting velocity aliasing. The observer determines the ambiguity area based on his or her knowledge. These results confirm the dealiasing and noise removing are vital elements in improving blood velocity estimation in cardiovascular diagnostic. Therefore, this study could use clinical tools based on color Doppler imaging.
关键词： Color Doppler,Blood flow velocity,Aliasing,Dealiasing,Smoothing
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Nara, Japan (2018.10.9-2018.10.12)] 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Blood Circulation Based on PPG Signals for Thermal Comfort Evaluation
摘要： This paper presents a new index for monitoring transition of blood circulation from Photoplethysmogram (PPG) signals for thermal comfort evaluation of users. Heat dissipation reaction through the dilation of blood vessels is person's intrinsic ability to control the thermal comfort. When body temperature is higher than normal temperature, blood circulation changes according to the dilation of blood vessels in distal end of the extremities. Blood circulation is often evaluated by an index of peripheral resistance corresponding to changes in blood flow velocity such as systolic/diastolic ratio (S/D) of flow velocities, resistance index and the pulsatility index. Unfortunately, such an index cannot be utilized in daily life for healthcare with using fitness trackers since the blood flow velocity is measured by either an ultrasonic Doppler blood flowmeter (UDF) or a Laser-Doppler flowmeter. Therefore, we propose a new index which is easily acquirable from PPG signals. First, a couple of variables correlating to the blood flow velocity is calculated from a rate of volumetric strain of Photoplethysmogram signals. Then the new index can be obtained as difference of these variables. Experimental results show the effectiveness of this index by confirming high correlation with S/D of UDF.
关键词： Peripheral blood circulation,volumetric strain,blood flow velocity,Photoplethysmogram signals
更新于2025-09-04 15:30:14