scholarly journals Pulsatile Flow Measurement by a Speckle Triangle Assessment

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuan Yuan ◽  
Yong Bi ◽  
Xiao Cao Gao ◽  
Wei Nan Gao
Keyword(s):  
Coronary Artery ◽  
Pulsatile Flow ◽  
Dynamic Range ◽  
Artery Bypass ◽  
High Dynamic Range ◽  
Laser Speckle ◽  
Flow Index ◽  
Mean Flow ◽  
Contrast Imaging ◽  
Phantom Experiment

The blood flow in the coronary artery (CA) is pulsatile and much higher than that measured in the brain, retina, and skin before. Its quantitative measurement is medically significant in the coronary artery bypass grafting (CABG). Here, to the best of our knowledge, we first detect the pulsatile flow using the laser speckle contrast imaging technique. Since the factors influencing the flow rate in the CA are complex, we developed a comprehensive model, a speckle triangle assessment (STA), to assess the characteristics of the flow: the speckle flow index (SFI), mean flow index (MFI), and pulsatility index (PI). The phantom experiment was performed and found that our customized setup possessed high dynamic range of the velocity measurement with good sensitivity. It also indicated that the pulsatile flow estimated by the speckle triangle assessment is promising to obtain a more accurate assessment of a coronary artery’s patency in the CABG.

Importance of Intraoperative Detection of Graft Patency by Using Transit Time Flowmetry and Its Impact on Revascularization of the Myocardium

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Mohamed Ayman Ezzat ◽  
Ahmed Abdel-Aziz Ibrahim ◽  
Yasser Mahmoud El Nahhas ◽  
Ahmed Mohamed Seif El-din ◽  
Mohamed Ahmed Gamal Mostafa
Keyword(s):  
Coronary Artery ◽  
Coronary Artery Bypass ◽  
Artery Bypass ◽  
Systolic Pressure ◽  
Graft Patency ◽  
Clinical Results ◽  
Mean Flow ◽  
Surgical Errors ◽  
Artery Disease ◽  
Surgery Department

Abstract Background Coronary artery bypass surgery (CABG) has contributed to an increase in survival, quality of life and life expectancy. The anastomotic quality and graft patency is directly associated with both early and long-term clinical results after CABG. It is a complication that can lead to refractory angina, myocardial infarction, arrhythmias, and even mortality. Objectives This study was aiming to evaluate the effect of use of TTFM on the outcome of CABG operations and it was carried out on 100 patients and examined 282 grafts, we use inotropic agents to maintain the systolic pressure at 90- 100 mmHg if the blood pressure was lower than that limit. Patients and Methods An observational exploratory study was carried on 100 patients operated in Police authority hospitals, cardiothoracic surgery department. The study period of the study was 6 months, study population: The included population will be patients with Coronary Artery Disease (CAD) undergoing Coronary Artery Bypass Grafting (CABG) surgery. Results TTFM data was described as two main readings which are MF in ml/min (mean flow), PI (pulsatility index) and it was measured for the all types of the grafts. In MF it was the highest in AO-OM system (34.5 ± 18.46) followed by LIMA- LAD system (33.0 ± 19.65) then AO-Diagonal (31.0 ± 26.38) and lastly AO-RCA(29.50 ± 32.22). For the PI the lowest measurements was 0.8 and it was for both LIMA to LAD and then 1.2 for AO-OM system and 1.4 for AO-DIAG system and 1.8 for AO-RCA system. The most important finding in this study which represents the usefulness of the usage of TTFM is how much grafts needed to be revised according to the grafts measurements and it was 14 grafts in 14 patients (one grafts for each patient) among 100 patients which account for 14%. Conclusion Regarding the other studies that compare the TTEM with other ways for detection of graft patency, they prefer the TTFM due to: TTFM is easy to use, accurate and relatively inexpensive, TTFM helps prevent missed technical surgical errors in distal and proximal anastomosis, it has shown that TTFM improved outcome in many situations, TTFM provides excellent documentation of the surgical outcome and allows for better understanding of procedural complications.

scholarly journals Deep Learning Enabled Laser Speckle Wavemeter with a High Dynamic Range

2020 ◽  
Vol 14 (9) ◽  
pp. 2000120 ◽  
Author(s):  
Roopam K. Gupta ◽  
Graham D. Bruce ◽  
Simon J. Powis ◽  
Kishan Dholakia
Keyword(s):  
Deep Learning ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Laser Speckle ◽  
High Dynamic

scholarly journals Guidelines for obtaining an absolute blood flow index with laser speckle contrast imaging

2021 ◽  
Author(s):  
Smrithi Sunil ◽  
Sharvari Zilpelwar ◽  
David A Boas ◽  
Dmitry D Postnov
Keyword(s):  
Blood Flow ◽  
Speckle Pattern ◽  
Quantitative Measure ◽  
Laser Speckle ◽  
Flow Index ◽  
Scattering Media ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Speckle Contrast ◽  
Blood Flow Index

Laser speckle contrast imaging (LSCI) is a technique broadly applied in research and clinical settings for full-field characterization of tissue perfusion. It is based on the analysis of speckle pattern contrast, which can be theoretically related to the decorrelation time - a quantitative measure of dynamics. A direct contrast to decorrelation time conversion, however, requires prior knowledge of specific parameters of the optical system and scattering media and thus is often impractical. For this reason, and because of the nature of some of the most common applications, LSCI is historically used to measure relative blood flow change. Over time, the belief that the absolute blood flow index measured with LSCI is not a reliable metric and thus should not be used has become more widespread. This belief has resulted from the use of LSCI to compare perfusion in different animal models and to obtain longitudinal blood flow index observations without proper consideration given to the stability of the measurement. Here, we aim to clarify the issues that give rise to variability in the repeatability of the quantitative blood flow index and to present guidelines on how to make robust absolute blood flow index measurements with conventional single-exposure LSCI. We also explain how to calibrate contrast to compare measurements from different systems and show examples of applications that are enabled by high repeatability.

scholarly journals Predicting successful lumbar plexus block using blood flow index measured by laser speckle contrast imaging

2019 ◽  
Author(s):  
Xi Wu ◽  
Pengcheng Li ◽  
Xiaohu Liu ◽  
Liangwei Meng ◽  
Dan Wang ◽  
...  
Keyword(s):  
Blood Flow ◽  
Femoral Nerve ◽  
Laser Speckle ◽  
Lateral Femoral Cutaneous Nerve ◽  
Lumbar Plexus ◽  
Flow Index ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Lumbar Plexus Block ◽  
Plexus Block

Abstract Background: Laser speckle contrast imaging (LSCI) is a powerful optical imaging technique for real-time and dynamic measurement of regional blood flow. The objective of this prospective observational study was to investigate blood flow after changes blockade of lumbar plexus or its three major branches respectively, with LSCI technique.Methods: This study included 47 adult patients scheduled for elective lower limb surgery. For the selective blockade of lumbar plexus, femoral nerve, obturator nerve, and lateral femoral cutaneous nerve, blood flow images and pinprick sensory scores of the blocked lower limb were recorded 5 min pre block and every 5 min for 30 min post block. Blood flow index (BFI) values of toes were calculated by LSCI software.Results: In this study, we have 21 cases of successful lumbar plexus blocks, 2 cases of failed lumbar plexus block, 8 cases of successful femoral nerve blocks, 8 cases of successful obturator nerve blocks, and 8 cases of successful lateral femoral cutaneous nerve blocks. The BFI values of all five toes were significantly increased as early as 5 min after successful lumbar plexus block, whereas no significant difference was found in BFI values after failed lumbar plexus block. BFI changes after successful selective blockade of femoral nerve, obturator nerve, or lateral femoral cutaneous nerve were negligible. BFI value of the big toe at 5 min after the successful lumbar plexus block was increased by 2.57 fold compared with the baseline value, which represented the highest increase among five tested toes. BFI value of the big toe at 10 min after lumbar plexus block showed great power to predict block outcome with a sensitivity of 100% and a specificity of 100%. The optimal cut-off value given by ROC analysis was 22.11 PU.Conclusions: Increased blood flow index measured by laser speckle contrast imaging is a reliable indicator of successful lumbar plexus block, but cannot indicate successful selective blocks of three major branches of the lumbar plexus. BFI value of the big toe at 10 min after lumbar plexus block could well predict block outcome with the cut-off value of 22.11 PU.Trial registration: NCT03169517 (Date of registration: May 25, 2017).

scholarly journals Predicting successful lumbar plexus block using blood flow index measured by laser speckle contrast imaging

2020 ◽  
Author(s):  
Xi Wu ◽  
Pengcheng Li ◽  
Xiaohu Liu ◽  
Liangwei Meng ◽  
Dan Wang ◽  
...  
Keyword(s):  
Blood Flow ◽  
Femoral Nerve ◽  
Laser Speckle ◽  
Lateral Femoral Cutaneous Nerve ◽  
Lumbar Plexus ◽  
Flow Index ◽  
Contrast Imaging ◽  
Laser Speckle Contrast Imaging ◽  
Lumbar Plexus Block ◽  
Plexus Block

Abstract Background: Laser speckle contrast imaging (LSCI) is a powerful optical imaging technique for real-time and dynamic measurement of regional blood flow. The objective of this prospective observational study was to investigate blood flow changes after blockade of lumbar plexus or its three major branches respectively, with LSCI technique. Methods: This study included 47 adult patients scheduled for elective lower limb surgery. For the selective blockade of lumbar plexus, femoral nerve, obturator nerve, and lateral femoral cutaneous nerve, blood flow images and pinprick sensory scores of the blocked lower limb were recorded 5 min pre block and every 5 min for 30 min post block. Blood flow index (BFI) values of toes were calculated by LSCI software. Results: In this study, we have 21 cases of successful lumbar plexus blocks, 2 cases of failed lumbar plexus block, 8 cases of successful femoral nerve blocks, 8 cases of successful obturator nerve blocks, and 8 cases of successful lateral femoral cutaneous nerve blocks. The BFI values of all five toes were significantly increased as early as 5 min after successful lumbar plexus block, whereas no significant difference was found in BFI values after failed lumbar plexus block. BFI changes after successful selective blockade of femoral nerve, obturator nerve, or lateral femoral cutaneous nerve were negligible. BFI value of the big toe at 5 min after the successful lumbar plexus block was increased by 2.57 fold compared with the baseline value, which represented the highest increase among five tested toes. BFI value of the big toe at 10 min after lumbar plexus block showed great power to predict block outcome with a sensitivity of 100% and a specificity of 100%. The optimal cut-off value given by ROC analysis was 22.11 PU. Conclusions: Increased blood flow index measured by laser speckle contrast imaging is a reliable indicator of successful lumbar plexus block, but cannot indicate successful selective blocks of three major branches of the lumbar plexus. BFI value of the big toe at 10 min after lumbar plexus block could well predict block outcome with the cut-off value of 22.11 PU.

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